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Beryllium increases the CD14(dim)CD16+ subset in the lung of chronic beryllium disease. Li Li,Hamzeh Nabeel,Gillespie May,Elliott Jill,Wang Jieru,Gottschall Eva Brigitte,Mroz Peggy M,Maier Lisa A PloS one CD14dimCD16+ and CD14brightCD16+ cells, which compose a minor population of monocytes in human peripheral blood mononuclear cells (PBMC), have been implicated in several inflammatory diseases. The aim of this study was to investigate whether this phenotype was present as a subset of lung infiltrative alveolar macrophages (AMs) in the granulomatous lung disease, chronic beryllium disease (CBD). The monocytes subsets was determined from PBMC cells and bronchoalveolar lavage (BAL) cells from CBD, beryllium sensitized Non-smoker (BeS-NS) and healthy subjects (HS) using flow cytometry. The impact of smoking on the AMs cell phenotype was determined by using BAL cells from BeS smokers (BeS-S). In comparison with the other monocyte subpopulations, CD14dimCD16+ cells were at decreased frequency in PBMCs of both BeS-NS and CBD and showed higher HLA-DR expression, compared to HS. The AMs from CBD and BeS-NS demonstrated a CD14dimCD16+phenotype, while CD14brightCD16+ cells were found at increased frequency in AMs of BeS, compared to HS. Fresh AMs from BeS-NS and CBD demonstrated significantly greater CD16, CD40, CD86 and HLA-DR than HS and BeS-S. The expression of CD16 on AMs from both CBD and BeS-NS was downregulated significantly after 10μM BeSO4 stimulation. The phagocytic activity of AMs decreased after 10μM BeSO4 treatment in both BeS-NS and CBD, although was altered or reduced in HS and BeS-S. These results suggest that Be increases the CD14dimCD16+ subsets in the lung of CBD subjects. We speculate that Be-stimulates the compartmentalization of a more mature CD16+ macrophage phenotype and that in turn these macrophages are a source of Th1 cytokines and chemokines that perpetuate the Be immune response in CBD. The protective effect of cigarette smoking in BeS-S may be due to the low expression of co-stimulatory markers on AMs from smokers as well as the decreased phagocytic function. 10.1371/journal.pone.0117276
No association between pyrite content and lung cell responses to coal particles. Zosky Graeme R,Bennett Ellen J,Pavez Macarena,Beamish B Basil Scientific reports There has been an increase in the identification of cases of coal workers' pneumoconiosis (CWP) in recent years around the world. While there are a range of possible explanations for this, studies have implicated the pyrite content of coal as a key determinant of CWP risk. However, experimental studies to support this link are limited. The aim of this study was to assess the association between the pyrite content, and subsequent release of bioavailable iron, in coal particles and the response of lung cells involved in the pathogenesis of CWP (epithelial cells, macrophages and fibroblasts). Using real-world Australian coal samples, we found no evidence of an association between the pyrite content of the coal and the magnitude of the detrimental cell response. We did find evidence of an increase in IL-8 production by epithelial cells with increasing bioavailable iron (p = 0.01), however, this was not linked to the pyrite content of the coal (p = 0.75) and we did not see any evidence of a positive association in the other cell types. Given the lack of association between the pyrite content of real-world coal particles and lung cell cytotoxicity (epithelial cells and macrophages), inflammatory cytokine production (epithelial cells, macrophages and fibroblasts), and cell proliferation (fibroblasts) our data do not support the use of coal pyrite content as a predictor of CWP risk. 10.1038/s41598-021-87517-z
Th17 can regulate silica-induced lung inflammation through an IL-1β-dependent mechanism. Journal of cellular and molecular medicine Silicosis is an occupational lung disease caused by the inhalation of silica dust and characterized by lung inflammation and fibrosis. Interleukin (IL)-1β is induced by silica and functions as the key pro-inflammatory cytokine in this process. The Th17 response, which is induced by IL-1β, has been reported very important in chronic human lung inflammatory diseases. To elucidate the underlying mechanisms of IL-1β and IL-17 in silicosis, we used anakinra and an anti-IL-17 monoclonal antibody (mAb) to block the receptor of IL-1β (IL-RI) and IL-17, respectively, in a mouse model of silicosis. We observed increased IL-1β expression and an enhanced Th17 response after silica instillation. Treatment with an IL-1 type I receptor (IL-1RI) antagonist anakinra substantially decreased silica-induced lung inflammation and the Th17 response. Lung inflammation and the accumulation of inflammatory cells were attenuated in the IL-17-neutralized silicosis group. IL-17 may promote lung inflammation by modulating the differentiation of Th1 and regulatory T cells (Tregs) and by regulating the production of IL-22 and IL-1β during the lung inflammation of silicosis. Silica may induce IL-1β production from alveolar macrophages and promote inflammation by initiating a Th17 response via an IL-1β/IL-1RI-dependent mechanism. The Th17 response could induce lung inflammation during the pathogenesis of silicosis by regulating the homoeostasis of the Th immune responses and affecting the production of IL-22 and IL-1β. This study describes a potentially important inflammatory mechanism of silicosis that may bring about novel therapies for this inflammatory and fibrotic disease. 10.1111/jcmm.12341
Cholesterol-dependent molecular mechanisms contribute to cationic amphiphilic drugs' prevention of silica-induced inflammation. European journal of cell biology Silicosis is considered an irreversible chronic inflammatory disease caused by the inhalation of crystalline silica (cSiO). The cycle of inflammation that drives silicosis and other particle-caused respiratory diseases is mediated by NLRP3 inflammasome activity in macrophages resulting in the release of IL-1β. Lysosomal membrane permeability (LMP) initiated by inhaled particles is the key regulatory step in leading to NLRP3 activity. In addition to its role in LMP, the lysosome is crucial to cellular cholesterol trafficking. Lysosomal cholesterol has been demonstrated to regulate LMP while cationic amphiphilic drugs (CADs) reduce cholesterol trafficking from lysosomes and promote endolysosomal cholesterol accumulation as seen in Niemann Pick disease. Using a bone marrow derived macrophage (BMdM) model, four CADs were examined for their potential to reduce cSiO-induced inflammation. Here we found that FDA-approved CAD drugs imipramine, hydroxychloroquine, fluvoxamine, and fluoxetine contributed to reduced LMP and IL-1β release in cSiO treated BMdM. These drugs inhibited lysosomal enzymatic activity of acid sphingomyelinase, decreased lysosomal proteolytic function, and increased lysosomal pH. CADs also demonstrated a significant increase in lysosomal-associated free cholesterol. Increased lysosomal cholesterol was associated with a significant reduction in cSiO induced LMP and IL-1β release. In contrast, reduced lysosomal cholesterol significantly exacerbated cSiO-induced IL-1β release and reduced the protective effect of CADs on IL-1β release following cSiO exposure. Taken together, these results suggest that CAD modification of lysosomal cholesterol may be used to reduce LMP and cSiO-induced inflammation and could prove an effective therapeutic for silicosis and other particle-caused respiratory diseases. 10.1016/j.ejcb.2023.151310
Inhibition of MARCO ameliorates silica-induced pulmonary fibrosis by regulating epithelial-mesenchymal transition. Yang Meng,Qian Xinlai,Wang Na,Ding Yingying,Li Haibin,Zhao Yingzheng,Yao Sanqiao Toxicology letters Epithelial-mesenchymal transition (EMT) is linked to fibrosis following exposure to silica. The scavenger receptor, macrophage receptor with collagenous structure (MARCO) plays an important role in silica-induced inflammation, however, the effect of MARCO on silica-induced fibrosis has not been identified. We hypothesized that MARCO would regulate EMT and be involved in the development of silicosis. Herein, we found that MARCO was highly expressed in lung tissue after exposure to silica and a MARCO inhibitor PolyG could alleviate pulmonary fibrosis in vivo. Our results confirmed that the expression of epithelial marker such as E-cadherin decreased, while the expression of mesenchymal markers, including vimentin and α-SMA increased after silica treatment. Furthermore, PolyG administration efficiently blocked the mRNA and protein expression of EMT markers and decreased the level of fibrosis-related transcription factors and proteins, such as Col1a1, Col3a1, Collagen I and Collagen III in the lungs of silica-exposed rats. The findings demonstrate that the macrophage membrane receptor MARCO controls the fibrotic response through regulating EMT in experimental silicosis and suggest a novel target for preventive intervention. 10.1016/j.toxlet.2018.10.031
Serum Osteopontin, KL-6, and Syndecan-4 as Potential Biomarkers in the Diagnosis of Coal Workers' Pneumoconiosis: A Case-Control Study. Pharmacogenomics and personalized medicine Background:Coal worker's pneumoconiosis (CWP) is a chronic occupational disease mainly caused by coal dust inhalation in miners. This study aimed to investigate the clinical value of Osteopontin (OPN), KL-6, Syndecan-4 and Gremlin-1 as serum biomarkers in CWP. Patients and Methods:We integrated reported lung tissues transcriptome data in pneumoconiosis patients with silica-exposed alveolar macrophage microarray data to identify four CWP-associated serum biomarkers. The serum concentrations of Osteopontin, Krebs von den Lungen-6 (KL-6), Syndecan-4 and Gremlin-1 were measured in 100 healthy controls (HCs), 100 dust-exposed workers (DEWs) and 200 patients of CWP. Receiver operating characteristic (ROC) curve analysis was used to determine the sensitivity, specificity, cut-off value and area under the curve (AUC) value of biomarkers. Results:The pulmonary function parameters decreased sequentially, and the serum OPN, KL-6, Syndecan-4 and Gremlin-1 concentrations were increased sequentially among the HC, DEW and CWP groups. Among all participants, multivariable analysis revealed that these four biomarkers were negatively correlated with the pulmonary function parameters (all <0.05). Compared with HCs, patients with higher OPN, KL-6, Syndecan-4 and Gremlin-1 had higher risk for CWP. The combination of OPN, KL-6, and Syndecan-4 can improve the diagnostic sensitivity and specificity of CWP patients differentiated from HCs or DEWs. Conclusion:OPN, KL-6 and Syndecan-4 are novel biomarkers that can be used for CWP auxiliary diagnosis. The combination of three biomarkers can improve the diagnostic values of CWP. 10.2147/PGPM.S409644
Inflammasome-Independent Leukotriene B Production Drives Crystalline Silica-Induced Sterile Inflammation. Hegde Bindu,Bodduluri Sobha R,Satpathy Shuchismita R,Alghsham Ruqaih S,Jala Venkatakrishna R,Uriarte Silvia M,Chung Dong-Hoon,Lawrenz Matthew B,Haribabu Bodduluri Journal of immunology (Baltimore, Md. : 1950) Silicosis is a lung inflammatory disease caused by chronic exposure to crystalline silica (CS). Leukotriene B (LTB) plays an important role in neutrophilic inflammation, which drives silicosis and promotes lung cancer. In this study, we examined the mechanisms involved in CS-induced inflammatory pathways. Phagocytosis of CS particles is essential for the production of LTB and IL-1β in mouse macrophages, mast cells, and neutrophils. Phagosomes enclosing CS particles trigger the assembly of lipidosome in the cytoplasm, which is likely the primary source of CS-induced LTB production. Activation of the JNK pathway is essential for both CS-induced LTB and IL-1β production. Studies with bafilomycin-A1- and NLRP3-deficient mice revealed that LTB synthesis in the lipidosome is independent of inflammasome activation. Small interfering RNA knockdown and confocal microscopy studies showed that GTPases Rab5c, Rab40c along with JNK1 are essential for lipidosome formation and LTB production. BI-78D3, a JNK inhibitor, abrogated CS-induced neutrophilic inflammation in vivo in an air pouch model. These results highlight an inflammasome-independent and JNK activation-dependent lipidosome pathway as a regulator of LTB synthesis and CS-induced sterile inflammation. 10.4049/jimmunol.1701504
Clinical significance of serum anti-GM-CSF autoantibody levels in autoimmune pulmonary alveolar proteinosis. Nishimura Masaki,Yamaguchi Etsuro,Takahashi Ayumu,Asai Nobuhiro,Katsuda Eisuke,Ohta Toyohiro,Ohtsuka Yoshinori,Kosaka Kenshi,Matsubara Ayako,Tanaka Hiroyuki,Yokoe Norihito,Kubo Akihito,Konno Satoshi,Baba Kenji Biomarkers in medicine AIM:Precise clinical significance of antigranulocyte-macrophage colony stimulating factor (GM-CSF) autoantibody levels in autoimmune pulmonary alveolar proteinosis (aPAP) has not been well studied. METHODS:We obtained sera from 50 healthy controls, 46 aPAP patients, 50 with sarcoidosis, 52 with idiopathic interstitial pneumonia and 75 with pneumoconiosis. The clinical course of aPAP patients was assessed by scoring computed tomography images in 19 patients. RESULTS:The cut-off level of anti-GM-CSF IgG for discrimination between aPAP and other diffuse lung diseases was 2.8 μg/ml with 100% sensitivity and 98% specificity. Antibody levels at baseline were significantly lower in the improved group than in the unimproved group (p = 0.008). CONCLUSION:Our results indicate the existence of threshold levels of serum anti-GM-CSF IgG for the development and persistence of aPAP. 10.2217/bmm-2017-0362
Glycogen metabolism reprogramming promotes inflammation in coal dust-exposed lung. Ecotoxicology and environmental safety Long-term coal dust exposure triggers complex inflammatory processes in the coal workers' pneumoconiosis (CWP) lungs. The progress of the inflammation is reported to be affected by disordered cell metabolism. However, the changes in the metabolic reprogramming associated with the pulmonary inflammation induced by the coal dust particles are unknown. Herein, we show that coal dust exposure causes glycogen accumulation and the reprogramming of glucose metabolism in the CWP lung. The glycogen accumulation caused by coal dust is mainly due to macrophages, which reprogram glycogen metabolism and trigger an inflammatory response. In addition, 2-deoxy-D-glucose (2-DG) reduced glycogen content in macrophages, which was accompanied by mitigated inflammation and restrained NF-κB activation. Accordingly, we have pinpointed a novel and crucial metabolic pathway that is an essential regulator of the inflammatory phenotype of coal dust-exposed macrophages. These results shed light on new ways to regulate CWP inflammation. 10.1016/j.ecoenv.2022.113913
Macrophage derived miR-7219-3p-containing exosomes mediate fibroblast trans-differentiation by targeting SPRY1 in silicosis. Toxicology Silicosis is one of the most serious occupational diseases with the main feature of inflammatory cell infiltration, fibroblasts activation, and large deposition of extracellular matrix in the lung. Increasing evidence indicates that macrophage-derived exosomes may play an important role in the development of silicosis by transferring their loaded microRNAs (miRNAs). Hence we carried out high-throughput sequencing to identify the expression of exosomal miRNA from macrophages exposed to silica or not in the previous study. Then we verified that miR-7219-3p was significantly up-regulated in macrophages and their exosomes after silica-exposure, as well as in the silicotic mice model by qRT-PCR, subsequent experiments confirmed that the increase of miR-7219-3p facilitated fibroblast to myofibroblast trans-differentiation (FMT), as well as cell proliferation and migration. Spouty1 (SPRY1), which served as a negative modulator of the Ras/ERK/MAPK signaling pathway, was verified as the target gene of miR-7219-3p, the knockdown or over-expression of SPRY1 apparently promoted or inhibited FMT via the Ras/ERK/MAPK signaling pathway. Furthermore, the inhibition of exosomal miR-7219-3p partially suppressed FMT and silica-induced pulmonary fibrosis in vitro and in vivo. In brief, our results demonstrated that exosomal miR-7219-3p played an important role in FMT and might be a novel therapeutic target of silicosis. 10.1016/j.tox.2022.153310
Polymorphism of FCGR3A gene in chronic beryllium disease. Liu Bing,Maier Lisa A,Hamzeh Nabeel,MacPhail Kristyn,Mroz Margaret M,Liu Hongbo,Li Li Genes and immunity Previously we showed that alveolar macrophages (AMs) from patients with chronic beryllium disease (CBD) and beryllium sensitization (BeS) demonstrated significantly greater cell surface CD16 (encoded by the FCGR3A gene) than controls. We hypothesized that these differences were related to polymorphisms in the FCGR3A gene. This study was to determine the association between FCGR3A polymorphisms in CBD, BeS versus controls as well as clinical data, providing potential information about disease pathogenesis, risk, and activity. A total of 189 CBD/154 BeS/150 controls (92 Be-exposed non-diseased and 58 healthy controls) were included in this study. Sequence-specific primers polymerase chain reaction (PCR-SSP) was used to determine FCGR3A 158V/F polymorphisms. We found significantly higher frequencies of the 158V allele (OR: 1.60 (CI: 1.17-2.19), p = 0.004) and 158VV homozygotes (OR: 2.97 (CI: 1.48-5.97) p = 0.007) in CBD versus controls. No differences were found in the frequencies of FCGR3A alleles or genotypes between BeS versus controls and CBD versus BeS. Average changes in exercise testing maximum workload (Wlm), maximum oxygen consumption (VOm), and diffusion capacity of carbon monoxide (DLCO) demonstrated greater decline over time in those CBD cases with the 158VV gene, modeled between 10 and 40 years from first beryllium exposure. The FCGR3A V158F polymorphism is associated with CBD compared to BeS and controls and may impact lung function in CBD. 10.1038/s41435-018-0046-8
Defense and protection mechanisms in lung exposed to asbestiform fiber: the role of macrophage migration inhibitory factor and heme oxygenase-1. Loreto Carla,Caltabiano Rosario,Graziano Adriana Carol Eleonora,Castorina Sergio,Lombardo Claudia,Filetti Vera,Vitale Ermanno,Rapisarda Giuseppe,Cardile Venera,Ledda Caterina,Rapisarda Venerando European journal of histochemistry : EJH Fluoro-edenite (FE), an asbestiform fiber, is responsible for many respiratory pathologies: chronic obstructive diseases, pleural plaques, fibrosis, and malignant mesothelioma. Macrophage migration inhibitory factor (MIF) is one of the first cytokines produced in response to lung tissue damage. Heme oxygenase-1 (HO-1) is a protein with protective effects against oxidative stress. It is up regulated by several stimuli including pro-inflammatory cytokines and factors that promote oxidative stress. In this research, the in vivo model of sheep lungs naturally exposed to FE was studied in order to shed light on the pathophysiological events sustaining exposure to fibers, by determining immunohistochemical lung expression of MIF and HO-1. Protein levels expression of HO-1 and MIF were also evaluated in human primary lung fibroblasts after exposure to FE fibers in vitro. In exposed sheep lungs, MIF and HO-1 immunoexpression were spread involving the intraparenchymal stroma around bronchioles, interstitium between alveoli, alveolar epithelium and macrophages. High MIF immunoexpression prevails in macrophages. Similar results were obtained in vitro, but significantly higher values were only detected for HO-1 at concentrations of 50 and 100 μg/mL of FE fibers. MIF and HO-1 expressions seem to play a role in lung self-protection against uncontrolled chronic inflammation, thus counteracting the strong link with cancer development, induced by exposure to FE. Further studies will be conducted in order to add more information about the role of MIF and HO-1 in the toxicity FE-induced. 10.4081/ejh.2020.3073
Role of SOD3 in silica-related lung fibrosis and pulmonary vascular remodeling. Respiratory research BACKGROUND:Work-place exposure to silica dust may lead to progressive lung inflammation culminating in the development of silicosis, an irreversible condition that can be complicated by onset of pulmonary hypertension (PH). The molecular mechanisms leading to the development of PH and lung fibrosis in response to silica are not well understood. Oxidant/antioxidant imbalance in the lung may promote fibroproliferation and vascular smooth muscle proliferation, ultimately leading to the development of PH. Herein, we analyze the development of PH and lung fibrosis in mice deficient in extracellular superoxide dismutase (SOD3), an enzyme with anti-oxidant activity. METHODS:PH and silicosis were induced in wild-type and Sod3 mice through intratracheal injection of crystalline silica at dose 0.4 g/kg. Pulmonary hypertension and lung fibrosis were characterized by changes in right ventricular systolic pressure (RVSP) and collagen deposition 28 days following silica injections. Vascular remodeling was analyzed using immunohistochemistry and morphometric analysis. The expression of genes were analyzed using qRT-PCR and Western blot. RESULTS:C57BL6 mice exposed to silica showed attenuated expression of Sod3 in the lung suggesting a protective role for Sod3. Consistent with this, Sod3 mice developed more severe fibrotic inflammatory nodules with increased collagen deposition. Furthermore, the expression of genes involved in tissue remodeling (Timp1), fibrotic lesion formation (Fsp1) and inflammatory response (Mcp1) were significantly elevated in Sod3 mice compared to Sod3 mice treated with silica. Infiltration of neutrophils and activated macrophages into affected lung was significantly higher in Sod3 deficient mice. In addition, silica produced more profound effects on elevation of RVSP in Sod3 compared to wild-type littermate. Increase in RVSP was concomitant with hypertrophy of pulmonary arteries located in silicotic nodules of both mouse strains, however, vascular remodeling in unaffected areas of lung was detected only in Sod3 mice. CONCLUSIONS:Our data suggest that Sod3 and extracellular oxidative stress may play an important role in the development of pneumoconiosis and pulmonary vascular remodeling following exposure to environmental and occupational silica. 10.1186/s12931-018-0933-6
Autoimmune/inflammatory syndrome induced by adjuvants (ASIA) 2013: Unveiling the pathogenic, clinical and diagnostic aspects. Perricone Carlo,Colafrancesco Serena,Mazor Roei D,Soriano Alessandra,Agmon-Levin Nancy,Shoenfeld Yehuda Journal of autoimmunity In 2011 a new syndrome termed 'ASIA Autoimmune/Inflammatory Syndrome Induced by Adjuvants' was defined pointing to summarize for the first time the spectrum of immune-mediated diseases triggered by an adjuvant stimulus such as chronic exposure to silicone, tetramethylpentadecane, pristane, aluminum and other adjuvants, as well as infectious components, that also may have an adjuvant effect. All these environmental factors have been found to induce autoimmunity by themselves both in animal models and in humans: for instance, silicone was associated with siliconosis, aluminum hydroxide with post-vaccination phenomena and macrophagic myofasciitis syndrome. Several mechanisms have been hypothesized to be involved in the onset of adjuvant-induced autoimmunity; a genetic favorable background plays a key role in the appearance on such vaccine-related diseases and also justifies the rarity of these phenomena. This paper will focus on protean facets which are part of ASIA, focusing on the roles and mechanisms of action of different adjuvants which lead to the autoimmune/inflammatory response. The data herein illustrate the critical role of environmental factors in the induction of autoimmunity. Indeed, it is the interplay of genetic susceptibility and environment that is the major player for the initiation of breach of tolerance. 10.1016/j.jaut.2013.10.004
Altered functions of alveolar macrophages and NK cells involved in asbestos-related diseases. Nishimura Yasumitsu,Maeda Megumi,Kumagai-Takei Naoko,Lee Suni,Matsuzaki Hidenori,Wada Yasuhiko,Nishiike-Wada Tamako,Iguchi Hiroshi,Otsuki Takemi Environmental health and preventive medicine Asbestos exposure causes asbestosis and malignant mesothelioma, disorders which remain difficult to cure. We focused on alveolar macrophages (AM) and natural killer (NK) cells in asbestosis and mesothelioma, respectively, and examined their functions upon exposure to asbestos or in patients with mesothelioma. Exposure to asbestos caused rat AM to exhibit high production of transforming growth factor-beta (TGF-β) with prolonged survival in the absence of other cells, not simultaneously with the apoptosis caused by asbestos. The NK cell line showed impaired cytotoxicity with altered expression of activating receptors upon exposure to asbestos, and primary NK cells in culture with asbestos and peripheral blood NK cells in mesothelioma shared a decrease in expression of NKp46, a representative activating receptor. The AM finding indicates that AM contribute to asbestosis by playing a direct role in the fibrogenic response, as well as the inflammatory response. The response of NK cells indicates that exposure to asbestos has an immune-suppressive effect, as well as a tumorigenic effect. Our studies therefore reveal novel effects of asbestos exposure on AM and tumor immunity, which may represent valuable information for construction of a strategy for prevention and cure of asbestosis and malignant mesothelioma. 10.1007/s12199-013-0333-y
[Research progress in pathogenesis of pneumoconiosis]. Jin F L,Zhang L X,Chen K,Tian Y G,Li J S Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases Pneumoconiosis is an occupational lung disease that is mainly caused by diffuse fibrosis of lung tissue due to long-term inhalation of productive dust during occupational activities and retention in the lungs. Macrophages, epithelial cells and other cells can release a large number of cytokines, such as transforming growth factor-β, monocyte chemotactic protein-1, etc. These cytokines can participate in pathologies such as local injury, inflammatory response, and pulmonary fibrosis. This article reviews the role of cytokines in the pathogenesis of pneumoconiosis in order to provide a basis for further research. 10.3760/cma.j.cn121094-20200219-00064
Type 2 Immune Mechanisms in Carbon Nanotube-Induced Lung Fibrosis. Frontiers in immunology T helper (Th) 2-dependent type 2 immune pathways have been recognized as an important driver for the development of fibrosis. Upon stimulation, activated Th2 immune cells and type 2 cytokines interact with inflammatory and tissue repair functions to stimulate an overzealous reparative response to tissue damage, leading to organ fibrosis and destruction. In this connection, type 2 pathways are activated by a variety of insults and pathological conditions to modulate the response. Carbon nanotubes (CNTs) are nanomaterials with a wide range of applications. However, pulmonary exposure to CNTs causes a number of pathologic outcomes in animal lungs, dominated by inflammation and fibrosis. These findings, alongside the rapidly expanding production and commercialization of CNTs and CNT-containing materials in recent years, have raised concerns on the health risk of CNT exposure in humans. The CNT-induced pulmonary fibrotic lesions resemble those of human fibrotic lung diseases, such as idiopathic pulmonary fibrosis and pneumoconiosis, to a certain extent with regard to disease development and pathological features. In fibrotic scenarios, immune cells are activated including varying immune pathways, ranging from innate immune cell activation to autoimmune disease. These events often precede and/or accompany the occurrence of fibrosis. Upon CNT exposure, significant induction and activation of Th2 cells and type 2 cytokines in the lungs are observed. Moreover, type 2 pathways are shown to play important roles in promoting CNT-induced lung fibrosis by producing type 2 pro-fibrotic factors and inducing the reparative phenotypes of macrophages in response to CNTs. In light of the vastly increased demand for nanosafety and the apparent induction and multiple roles of type 2 immune pathways in lung fibrosis, we review the current literature on CNT-induced lung fibrosis, with a focus on the induction and activation of type 2 responses by CNTs and the stimulating function of type 2 signaling on pulmonary fibrosis development. These analyses provide new insights into the mechanistic understanding of CNT-induced lung fibrosis, as well as the potential of using type 2 responses as a monitoring target and therapeutic strategy for human fibrotic lung disease. 10.3389/fimmu.2018.01120
Mechanisms of organ fibrosis: Emerging concepts and implications for novel treatment strategies. Molecular aspects of medicine Fibrosis, or tissue scarring, develops as a pathological deviation from the physiological wound healing response and can occur in various organs such as the heart, lung, liver, kidney, skin, and bone marrow. Organ fibrosis significantly contributes to global morbidity and mortality. A broad spectrum of etiologies can cause fibrosis, including acute and chronic ischemia, hypertension, chronic viral infection (e.g., viral hepatitis), environmental exposure (e.g., pneumoconiosis, alcohol, nutrition, smoking) and genetic diseases (e.g., cystic fibrosis, alpha-1-antitrypsin deficiency). Common mechanisms across organs and disease etiologies involve a sustained injury to parenchymal cells that triggers a wound healing response, which becomes deregulated in the disease process. A transformation of resting fibroblasts into myofibroblasts with excessive extracellular matrix production constitutes the hallmark of disease, however, multiple other cell types such as immune cells, predominantly monocytes/macrophages, endothelial cells, and parenchymal cells form a complex network of profibrotic cellular crosstalk. Across organs, leading mediators include growth factors like transforming growth factor-β and platelet-derived growth factor, cytokines like interleukin-10, interleukin-13, interleukin-17, and danger-associated molecular patterns. More recently, insights into fibrosis regression and resolution of chronic conditions have deepened our understanding of beneficial, protective effects of immune cells, soluble mediators and intracellular signaling. Further in-depth insights into the mechanisms of fibrogenesis can provide the rationale for therapeutic interventions and the development of targeted antifibrotic agents. This review gives insight into shared responses and cellular mechanisms across organs and etiologies, aiming to paint a comprehensive picture of fibrotic diseases in both experimental settings and in human pathology. 10.1016/j.mam.2023.101191
Gefitinib and fostamatinib target EGFR and SYK to attenuate silicosis: a multi-omics study with drug exploration. Signal transduction and targeted therapy Silicosis is the most prevalent and fatal occupational disease with no effective therapeutics, and currently used drugs cannot reverse the disease progress. Worse still, there are still challenges to be addressed to fully decipher the intricated pathogenesis. Thus, specifying the essential mechanisms and targets in silicosis progression then exploring anti-silicosis pharmacuticals are desperately needed. In this work, multi-omics atlas was constructed to depict the pivotal abnormalities of silicosis and develop targeted agents. By utilizing an unbiased and time-resolved analysis of the transcriptome, proteome and phosphoproteome of a silicosis mouse model, we have verified the significant differences in transcript, protein, kinase activity and signaling pathway level during silicosis progression, in which the importance of essential biological processes such as macrophage activation, chemotaxis, immune cell recruitment and chronic inflammation were emphasized. Notably, the phosphorylation of EGFR (p-EGFR) and SYK (p-SYK) were identified as potential therapeutic targets in the progression of silicosis. To inhibit and validate these targets, we tested fostamatinib (targeting SYK) and Gefitinib (targeting EGFR), and both drugs effectively ameliorated pulmonary dysfunction and inhibited the progression of inflammation and fibrosis. Overall, our drug discovery with multi-omics approach provides novel and viable therapeutic strategies for the treatment of silicosis. 10.1038/s41392-022-00959-3
The cGAS-STING Pathway: A Promising Immunotherapy Target. Ou Liang,Zhang Ao,Cheng Yuxing,Chen Ying Frontiers in immunology With the continuous development of immunotherapy, researchers have paid more attention to the specific immune regulatory mechanisms of various immune responses in different diseases. As a novel and vital innate immune signal pathway, the cGAS-STING signal pathway activated by nucleic acid substances, interplays with other immune responses, by which it participates in regulating cancer, autoimmune and inflammatory diseases, microbial and parasitic infectious diseases, and other diseases. With the exception of its role in innate immunity, the growing list of researches demonstrated expanding roles of the cGAS-STING signal pathway in bridging the innate immunity (macrophage polarization) with the adaptive immunity (T lymphocytes differentiation). Macrophages and T lymphocytes are the most representative cells of innate immunity and adaptive immunity, respectively. Their polarization or differentiation are involved in the pathogenesis and progression of various diseases. Here we mainly summarized recent advanced discoveries of how the cGAS-STING signal pathway regulated macrophages polarization and T lymphocytes differentiation in various diseases and vaccine applications, providing a promising direction for the development and clinical application of immunotherapeutic strategies for related diseases. 10.3389/fimmu.2021.795048
[The study of the impact by atractylenolide-1 on inflammatory cytokine, autophagy and apoptosis in alveolar macrophages of silicosis patients]. Tan S Y,Zou H,Yang C,Chen G,Chen S Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases To explore the effect of atractylenolide-1 (ATL-Ⅰ) on alveolar macrophages in silicosis patients. In December 2019, 12 male silicosis patients treated in Beidaihe Sanatorium for Chinese Coal Miners from July to September 2019 were selected by random sampling. Their alveolar macrophages were collected and divided into control group, ATL-Ⅰ group (100 μmol/L) and dimethyl sulfoxide (DMSO) group (100 μmol/L) . The exprossion levels of inflammatory factor interleukin-1β (IL-1β) , interleukin-6 (IL-6) , tumor necrosis factor α (TNF-α) were detected by enzyme-linked immunosorbent assay. The expression levels of autophagy associated protein microtubule associated protein light chain 3 (LC3) , autophagy substrate protein p62, lysosome associated membrane protein 2 (LAMP2) , apoptosis associated protein Cleaved caspase-3, nuclear factor kappa B (NF-κB) and its phosphorylated form (p-NF-κB) were detected by Western blot. Compared with the control group and DMSO group, the expression levels of IL-1β, IL-6, TNF-α in alveolar macrophages decreased significantly in the ATL-Ⅰ group (<0.05) , and the expression levels of p-NF-κB, the ratio of LC3-Ⅱ/LC3-Ⅰ also decreased significantly in the ATL-Ⅰ group (<0.05) . However, the expression levels of NF-κB, LAMP2, p62 and Cleaved caspase-3 in the ATL-Ⅰ group were not statistically different from those in the control group and DMSO group (>0.05) . There was no statistically significant differences in the expression of the above indexes between the control group and DMSO group (>0.05) . ATL-Ⅰ may reduce the release of inflammatory factors from alveolar macrophages and inhibit the activity of autophagy in silicosis patients, but it may not reduce the level of apoptosis. 10.3760/cma.j.cn121094-20200601-00310
Atractylenolide III alleviates the apoptosis through inhibition of autophagy by the mTOR-dependent pathway in alveolar macrophages of human silicosis. Chen Shi,Tang Kun,Hu Peiwu,Tan Shiyi,Yang Shang,Yang Chang,Chen Gang,Luo Yixiao,Zou Hui Molecular and cellular biochemistry Silica-induced apoptosis of alveolar macrophages (AMs) is an essential part of silicosis formation. Autophagy tends to present a bidirectional effect on apoptosis. Our previous study found that the blockade of autophagy degradation might aggravate the apoptosis of AMs in human silicosis. We presume that targeting the autophagic pathway is regarded as a promising new strategy for silicosis fibrosis. As a main active component of the Atractylodes rhizome, Atractylenolide III (ATL-III) has been widely applied in clinical anti-inflammation. However, the effect and mechanism of ATL-III on autophagy in AMs of silicosis are unknown. In this study, we found that ATL-III might inhibit autophagy by mTOR-dependent manner, thereby improving the blockage of autophagic degradation in AMs. ATL-III alleviated the apoptosis of AMs in human silicosis. Furthermore, Rapamycin reversed the protective effect of ATL-III in AMs. These results indicate that ATL-III may be a potentially protective ingredient targeting autophagy for workers exposed to silica dust. These findings also suggest that inhibition of autophagy may be an effective way to alleviate the apoptosis of AMs in silicosis. 10.1007/s11010-020-03946-w
Atractylenolide III Ameliorated Autophagy Dysfunction via Epidermal Growth Factor Receptor-Mammalian Target of Rapamycin Signals and Alleviated Silicosis Fibrosis in Mice. Laboratory investigation; a journal of technical methods and pathology Atractylenolide III (ATL-III) is a major active constituent of the natural plant Atractylodes rhizome. Our previous study has shown that ATL-III may alleviate alveolar macrophage apoptosis via the inhibition of the mammalian target of rapamycin (mTOR)-mediated autophagy of human silicosis. Therefore, we aimed to further explore the function of ATL-III in autophagy, apoptosis, and pulmonary fibrosis by establishing the ATL-III-intervened silicosis mouse model in this study. Meanwhile, we sought and then verified potential autophagy-related signaling pathways by matching differentially expressed genes (attained by RNA sequencing) and the autophagy database. In this study, RNA-sequencing results implied that the epidermal growth factor receptor, the crucial upstream activator of mTOR, was seen as a potential autophagy-regulatory molecule in the ATL-III-intervened silicosis mouse model. The finding of this study was that ATL-III might improve the disorder of autophagic degradation via the activation of epidermal growth factor receptor-mTOR signals in the pulmonary tissue of the silicosis mouse model. ATL-III also alleviated cell apoptosis and silicotic fibrosis. Overall, we supposed that ATL-III might be a potential protective medicine, which had a regulatory effect on autophagy, for the intervention of silicotic fibrosis. In the future, the therapeutic drugs for silicosis should be further focused on the development and application of such natural autophagy agents. 10.1016/j.labinv.2022.100024
Sodium tanshinone IIA sulfonate attenuates silica-induced pulmonary fibrosis in rats via activation of the Nrf2 and thioredoxin system. Zhu Zhonghui,Li Qiuyue,Xu Chunjie,Zhao Jing,Li Siling,Wang Yan,Tian Lin Environmental toxicology and pharmacology Silicosis is characterized by pulmonary fibrosis due to long-term inhalation of silica particles. Although the cause of this serious disease is known, its pathogenesis remains unclear and there are currently no specific treatments. Recent studies have shown that the anti-oxidant transcription factor Nrf2 is expressed at reduced levels in fibrotic foci, which may be related to disease progression. However, the molecular mechanisms by which this might occur have yet to be elucidated. Sodium tanshinone IIA sulfonate (STS), an extract of Salvia miltiorrhiza, is used in traditional Chinese medicine in the treatment of coronary heart disease. STS has been shown to play a strong anti-oxidative role in various organs. Here, we employed a rat model to explore the effects of STS on oxidative stress and the progression of fibrosis in silicosis. STS significantly reduced collagen deposition in the lungs, thereby antagonising silicosis. Immunohistochemical and immunofluorescence staining showed that Nrf2 was differentially expressed in lung cells during silica induced fibrosis, and chromatin immunoprecipitation-sequencing experiments demonstrated that Nrf2 promoted the expression of the antioxidant proteins thioredoxin and thioredoxin reductase. Our results suggest that the anti-fibrotic effects of STS may be related to upregulation of Nrf2 nuclear expression, especially in fibrotic lesions, and the promotion of thioredoxin and thioredoxin reductase expression. Our findings may open up new avenues for the development of STS as a treatment for silicosis. 10.1016/j.etap.2020.103461
[The study of smoking impact on autophagy in alveolar macrophages of human silicosis]. Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases To investigate the effect of smoking on autophagy in alveolar macrophages (AMs) of silicosis patients. In December 2019, a random sampling method was used to select 42 male patients with silicosis (19 cases of stage II and 23 cases of stage III) who were treated with large volume whole lung lavage from August to December 2017 in the Beidaihe sanatorium. According to the different smoking index of the study subjects (smoking index=smoking cigarette consumptions per day×years of smoking) , we divided them into high (Smoking index>400) , medium (200≤smoking index≤400) , low (smoking index <200) and non-smoking group. The levels of autophagy related proteins LC3, Beclin1, p62 and apoptosis related protein Cleaved Caspase-3 were detected by Western blot. The effects of smoking on autophagy activity of AMs in silicosis were analyzed. The ratio of autophagy related protein LC3 II/LC3 I, the expression of Beclin1, p62, and apoptosis related protein Cleaved Caspase-3 in the high smoking group were significantly higher than that of the middle, low smoking group and the non-smoking group (<0.05) . Smoking can aggravate the dysfunction of autophagic degradation in silicosis patients' AMs, which may accelerate the progress of silicosis through increasing apoptosis in AMs. 10.3760/cma.j.cn121094-20191226-00504
The emerging roles of a novel CCCH-type zinc finger protein, ZC3H4, in silica-induced epithelial to mesenchymal transition. Jiang Rong,Zhou Zewei,Liao Yan,Yang Fuhuang,Cheng Yusi,Huang Jie,Wang Jing,Chen Hong,Zhu Tiebing,Chao Jie Toxicology letters BACKGROUND:The epithelial to mesenchymal transition (EMT) contributes to fibrosis during silicosis. Zinc finger CCCH-type containing 4 protein (ZC3H4) is a novel CCCH-type zinc finger protein that activates inflammation in pulmonary macrophages during silicosis. However, whether ZC3H4 is involved in EMT during silicosis remains unclear. In this study, we investigated the circular ZC3H4 (circZC3H4) RNA/microRNA-212 (miR-212) axis as the upstream molecular mechanism regulating ZC3H4 expression and the downstream mechanism by which ZC3H4 regulates EMT as well as its accompanying migratory characteristics. METHODS:The protein levels were assessed via Western blotting and immunofluorescence staining. Scratch assays were used to analyze the increased mobility induced by silica. The CRISPR/Cas9 system and small interfering RNAs (siRNAs) were employed to analyze the regulatory mechanisms of ZC3H4 in EMT and migration changes. RESULTS:Specific knockdown of ZC3H4 blocked EMT and migration induced by silicon dioxide (SiO). Endoplasmic reticulum (ER) stress mediated the effects of ZC3H4 on EMT. circZC3H4 RNA served as an miR-212 sponge to regulate ZC3H4 expression, which played a pivotal role in EMT. Tissue samples from mice and patients confirmed the upregulation of ZC3H4 in alveolar epithelial cells. CONCLUSIONS:ZC3H4 may act as a novel regulator in the progression of SiO-induced EMT, which provides a reference for further pulmonary fibrosis research. 10.1016/j.toxlet.2019.02.014
Role of PI3K/Akt/mTOR pathway-mediated macrophage autophagy in affecting the phenotype transformation of lung fibroblasts induced by silica dust exposure. Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences OBJECTIVES:The phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway is one of the main signaling pathways related to autophagy. Autophagy plays a key role in the formation of silicosis fibrosis. The phenotypic transformation of lung fibroblasts into myofibroblasts is a hallmark of the transition from the inflammatory phase to the fibrotic phase in silicosis. This study aims to investigate whether the PI3K/Akt/mTOR pathway affects the phenotypic transformation of silicosis-induced lung fibroblasts into myofibroblasts via mediating macrophage autophagy. METHODS:The human monocytic leukemia cell line THP-1 cells were differentiated into macrophages by treating with 100 ng/mL of phorbol ester for 24 h. Macrophages were exposed to different concentrations (0, 25, 50, 100, 200, 400 μg/mL) and different times (0, 6, 12, 24, 48 h) of SiO dust suspension. The survival rate of macrophages was measured by cell counting kit-8 (CCK-8) method. Enzyme linked immunosorbent assay (ELISA) was used to measure the contents of transforming growth factor-β1 (TGF-β1) and tumor necrosis factor-α (TNF-α) in the cell supernatant. The co-culture system of macrophages and HFL-1 cells was established by transwell. A blank control group, a SiO group, a LY294002 group, a SC79 group, a LY294002+SiO group, and a SC79+SiO group were set up in this experiment. Macrophages in the LY294002+SiO group were pretreated with LY294002 (PI3K inhibitor) for 18 hours, and macrophages in the SC79+SiO group were pretreated with SC79 (Akt activator) for 24 hours, and then exposed to SiO (100 μg/mL) dust suspension for 12 hours. The expression of microtubule-associated protein 1 light chain 3 (LC3) protein in macrophages was detected by the immunofluorescence method. The protein expressions of PI3K, Akt, mTOR, Beclin-1, LC3 in macrophages, and collagen III (Col III), α-smooth muscle actin (α-SMA), fibronectin (FN), matrix metalloproteinase-1 (MMP-1), tissue metalloproteinase inhibitor-1 (TIMP-1) in HFL-1 cells were measured by Western blotting. RESULTS:After the macrophages were exposed to SiO dust suspension of different concentrations for 12 h, the survival rates of macrophages were gradually decreased with the increase of SiO concentration. Compared with the 0 μg/mL group, the survival rates of macrophages in the 100, 200, and 400 μg/mL groups were significantly decreased, and the concentrations of TGF-β1 and TNF-α in the cell supernatant were obviously increased (all <0.05). When 100 μg/mL SiO dust suspension was applied to macrophages, the survival rates of macrophages were decreased with the prolonged exposure time. Compared with the 0 h group, the survival rates of macrophages were significantly decreased (all <0.05), the concentrations of TGF-β1 and TNF-α in the cell supernatant were significantly increased, and the protein expression levels of Beclin-1 and LC3II were increased markedly in the 6, 12, 24, and 48 h groups (all <0.05). Immunofluorescence results demonstrated that after exposure to SiO (100 μg/mL) dust for 12 h, LC3 exhibited punctate aggregation and significantly higher fluorescence intensity compared to the blank control group (<0.05). Compared with the blank control group, the protein expressions of Col III, FN, α-SMA, MMP-1, and TIMP-1 in HFL-1 cells were up-regulated in the SiO group (all <0.05). Compared with the SiO group, the protein expressions of PI3K, Akt, and mTOR were down-regulated and the protein expressions of LC3II and Beclin-1 were up-regulated in macrophages (all <0.05), the contents of TNF-α and TGF-β1 in the cell supernatant were decreased (both <0.01), and the protein expressions of Col III, FN, α-SMA, MMP-1, and TIMP-1 in HFL-1 cells were down-regulated (all <0.05) in the LY294002+SiO group. Compared with the SiO group, the protein expressions of PI3K, Akt, and mTOR were up-regulated and the protein expressions of LC3II and Beclin-1 were down-regulated in macrophages (all <0.05), the contents of TNF-α and TGF-β1 in the cell supernatant were increased (both <0.01), and the protein expressions of Col III, FN, α-SMA, MMP-1, and TIMP-1 in HFL-1 cells were up-regulated (all <0.05) in the SC79+SiO group. CONCLUSIONS:Silica dust exposure inhibits the PI3K/Akt/mTOR pathway, increases autophagy and concentration of inflammatory factors in macrophages, and promotes the phenotype transformation of HFL-1 cells into myofibroblasts. The regulation of the PI3K/Akt/mTOR pathway can affect the autophagy induction and the concentration of inflammatory factors of macrophages by silica dust exposure, and then affect the phenotype transformation of HFL-1 cells into myofibroblasts induced by silica dust exposure. 10.11817/j.issn.1672-7347.2023.220581
Macrophages utilize the mitochondrial calcium uniporter for profibrotic polarization. Gu Linlin,Larson-Casey Jennifer L,Carter A Brent FASEB journal : official publication of the Federation of American Societies for Experimental Biology Fibrosis in multiple organs, including the liver, kidney, and lung, often occurs secondary to environmental exposure. Asbestos exposure is one important environmental cause of lung fibrosis. The mechanisms that mediate fibrosis is not fully understood, although mitochondrial oxidative stress in alveolar macrophages is critical for fibrosis development. Mitochondrial Ca levels can be associated with production of reactive oxygen species. Here, we show that patients with asbestosis have higher levels of mitochondrial Ca compared with normal patients. The mitochondrial calcium uniporter (MCU) is a highly selective ion channel that transports Ca into the mitochondrial matrix to modulate metabolism. Asbestos exposure increased mitochondrial Ca influx in alveolar macrophages from wild-type, but not MCU, mice. MCU expression polarized macrophages to a profibrotic phenotype after exposure to asbestos, and the profibrotic polarization was regulated by MCU-mediated ATP production. Profibrotic polarization was abrogated when MCU was absent or its activity was blocked. Of more importance, mice that were deficient in MCU were protected from pulmonary fibrosis. Regulation of mitochondrial Ca suggests that MCU may play a pivotal role in the development of fibrosis and could potentially be a therapeutic target for pulmonary fibrosis.-Gu, L., Larson-Casey, J. L., Carter, A. B. Macrophages utilize the mitochondrial calcium uniporter for profibrotic polarization. 10.1096/fj.201601371R
Human neutrophil peptide 1 promotes immune sterilization in vivo by reducing the virulence of multidrug-resistant Klebsiella pneumoniae and increasing the ability of macrophages. Biotechnology and applied biochemistry By studying the expression in patients and cell modeling in vitro, antimicrobial peptides for Klebsiella were screened. Killing curve and membrane permeability experiments are used to study the antibacterial effect of antimicrobial peptides in vitro. Cytotoxicity-related indicators including lipopolysaccharide (LPS), capsule polysaccharide (CPS), and outer membrane protein expression were measured. Intranasal inoculation of pneumoconiosis was used to construct a mouse infection model, and the survival rate and cytokine expression level were tested. Human neutrophil peptide 1 (HNP-1) showed a significant antibacterial effect, which improved the permeability of the outer membrane of K. pneumoniae. Moreover, HNP-1 decreased LPS, CPS content, and outer membrane proteins. K. pneumoniae infection decreased antimicrobial peptide, oxidative stress, and autophagy-related genes, while HNP-1 increased these genes. After coculture with macrophages, the endocytosis of macrophages is enhanced and the bacterial load is greater in the K. pneumoniae + peptide group. Besides, higher levels of pp38 and pp65 in the K. pneumoniae + peptide group. HNP-1 rescued the cytotoxicity induced by K. pneumoniae. The survival rate is significantly improved after K. pneumoniae is treated by HNP-1. All cytokines in the peptide group were significantly higher. HNP-1 promotes immune sterilization by reducing the virulence of multidrug-resistant K. pneumoniae and increasing the ability of macrophages. 10.1002/bab.2270
IL-10 producing B cells regulated 1,3-β-glucan induced Th responses in coordinated with Treg. Zhang Qi,Lu Yiping,Liu Fangwei Immunology letters Repeated exposure to fungi-contaminated dust can lead to multiple adverse effects on the lung, such as hypersensitivity pneumonitis, granuloma even irreversible fibrosis. 1,3-β-glucan, a major cell wall component of fungi, is considered as its exposure biomarker. Existing studies showed that a series of Th responses were involved in 1,3-β-glucan induced hypersensitivity pneumonitis, in which macrophages, Treg, and IL-10 producing B cells were reported to participate. The reciprocal interaction among those critical immune cells in 1,3-β-glucan induced inflammation was not investigated yet. To clarify the regulatory mechanism of IL-10 producing B cells on Th and Treg, the current study set up a primary cell co-culture system. The anti-CD22 antibody was injected intraperitoneally to generate IL-10 producing B cells deficiency mouse model. Cells were isolated and purified from C57BL∖6 mice in different groups. Flow cytometry was used to check the phenotype of different cell subtypes. CBA assay and real-time PCR were used to examine the levels of multiple cytokines. Our results indicated that IL-10 producing B cells could modulate the 1,3-β-glucan induced inflammatory response. The modulation of IL-10 producing B cells on Th response after 1,3-β-glucan treatment was cell contact independent. What's more, the modulation pattern of IL-10 producing B cells might be impaired without Treg response. IL-10-producing B cells regulated 1,3-β-glucan induced Th responses in co-ordination with Treg cells. 10.1016/j.imlet.2021.04.011
Therapeutic effects of adipose-tissue-derived mesenchymal stromal cells and their extracellular vesicles in experimental silicosis. Bandeira Elga,Oliveira Helena,Silva Johnatas D,Menna-Barreto Rubem F S,Takyia Christina M,Suk Jung S,Witwer Kenneth W,Paulaitis Michael E,Hanes Justin,Rocco Patricia R M,Morales Marcelo M Respiratory research BACKGROUND:Silicosis is an occupational disease that affects workers who inhale silica particles, leading to extensive lung fibrosis and ultimately causing respiratory failure. Mesenchymal stromal cells (MSCs) have been shown to exert therapeutic effects in lung diseases and represent an alternative treatment for silicosis. Recently, it has been suggested that similar effects can be achieved by the therapeutic use of extracellular vesicles (EVs) obtained from MSCs. The aim of this study was to investigate the effects of adipose-tissue-derived MSCs (AD-MSCs) or their EVs in a model of silicosis. METHODS:Silicosis was induced by intratracheal instillation of silica in C57BL/6 mice. After the onset of disease, animals received saline, AD-MSCs, or EVs, intratracheally. RESULTS:At day 30, AD-MSCs and EVs led to a reduction in collagen fiber content, size of granuloma, and in the number of macrophages inside granuloma and in the alveolar septa. In addition, the expression levels of interleukin 1β and transforming growth factor beta in the lungs were decreased. Higher dose of EVs also reduced lung static elastance when compared with the untreated silicosis group. CONCLUSIONS:Both AD-MSCs and EVs, locally delivered, ameliorated fibrosis and inflammation, but dose-enhanced EVs yielded better therapeutic outcomes in this model of silicosis. 10.1186/s12931-018-0802-3
Lipopolysaccharides promote pulmonary fibrosis in silicosis through the aggravation of apoptosis and inflammation in alveolar macrophages. Tan Shiyi,Yang Shang,Chen Mingke,Wang Yurun,Zhu Li,Sun Zhiqian,Chen Shi Open life sciences Alveolar macrophages (AMs) play an important defensive role by removing dust and bacteria from alveoli. Apoptosis of AMs is associated with lung fibrosis; however, the relationship between this apoptotic event and environmental factors, such as the presence of lipopolysaccharides (LPSs) in the workplace, has not yet been addressed. To investigate whether exposure to LPS can exacerbate fibrosis, we collected AMs from 12 male workers exposed to silica and incubated them in the presence and absence of LPS for 24 h. We show that the levels of cleaved caspase-3 and pro-inflammatory cytokines interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha were increased in these AMs following LPS treatment. Moreover, we demonstrate that LPS exposure aggravated apoptosis and the release of inflammatory factors in AMs in a mouse model of silicosis, which eventually promoted pulmonary fibrosis. These results suggest that exposure to LPS may accelerate the progression of pulmonary fibrosis in silicosis by increasing apoptosis and inflammation in AMs. 10.1515/biol-2020-0061
Thalidomide Alleviates Pulmonary Fibrosis Induced by Silica in Mice by Inhibiting ER Stress and the TLR4-NF-κB Pathway. International journal of molecular sciences Silicosis is the most prevalent occupational disease in China. It is a form of pulmonary fibrosis caused by the inhalation of silicon particles. As there is no cure for the potentially lethal and progressive condition, the treatment of silicotic fibrosis is an important and difficult problem to address. Thalidomide, a drug with anti-inflammatory and immunoregulatory properties, has been reported to have lung-protective effects. The purpose of this study was to observe the therapeutic effect of thalidomide on silicotic mice and to determine the protective mechanism. By using silicotic mice models and MH-S cells, we found the expression of endoplasmic reticulum stress (ER stress) and Toll-like receptor 4 (TLR4)-nuclear factor kappa-B (NF-κB) pathway as well as inflammation-related factors were upregulated in the macrophages of silicotic mice. The same indexes were detected in silica-stimulated MH-S cells, and the results were consistent with those in vivo. That is, silica activated ER stress and the TLR4-NF-κB pathway as well as the inflammatory response in vitro. Treating both silicotic mice and silica-stimulated MH-S cells with thalidomide inhibited ER stress and the TLR4-NF-κB pathway as well as the inflammatory response. The present study demonstrates thalidomide as a potential therapeutic agent against silicosis. 10.3390/ijms23105656
Intratracheally administered iron oxide nanoparticles induced murine lung inflammation depending on T cells and B cells. Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association Iron oxide nanoparticles (FeO NPs), produced in track traffic system and a wide range of industrial production, poses a great threat to human health. However, there is little research about the mechanism of FeO NPs toxicity on respiratory system. Rag1 mice which lack functional T and B cells were intratracheally challenged with FeO NPs, and interleukin (IL)-33 as an activator of group 2 innate lymphoid cells (ILC2s) to observe ILC2s changes. The lung inflammatory response to FeO NPs was alleviated in Rag1 mice compared with wild type (WT) mice. Infiltration of inflammatory cells and collagen deposition in tissue, leukocyte numbers (neutrophils, macrophages and lymphocytes), cytokine levels, such as IL-6, IL-13 and thymic stromal lymphopoietin (TSLP), and expression of Toll-like receptor (TLR)2, TLR4, and downstream myeloid differentiation factor (MyD)88, nuclear factor (NF)-κB and tumor necrosis factor (TNF)-α were decreased in lungs. FeO NPs markedly elevated ILC2s compared with the control, but ILC2s numbers were much lower compared with IL-33 in both WT and Rag1 mice. Furthermore, ILC2s amounts were strongly greater in Rag1 mice than WT mice. Our results suggested that FeO NPs induced sub-chronic pulmonary inflammation, which is majorly dependent on T cells and B cells rather than ILC2s. 10.1016/j.fct.2023.113735
3-methyadenine inhibits lipopolysaccharides-induced pulmonary inflammation at the early stage of silicosis via blocking NF-κB signaling pathway. Zhang Yujing,Huang Shuai,Tan Shiyi,Chen Mingke,Yang Shang,Chen Shi Toxicology and industrial health Occupational exposure to silica dust is related to pulmonary inflammation and silicosis. Lipopolysaccharides (LPSs) could aggravate apoptosis in alveolar macrophages (AMs) of human silicosis through autophagy, yet how the reduction of autophagy attenuated LPS-induced lung injury and the related mechanisms need to be investigated. In the study, we aim to understand the role of 3-methyladenine (3-MA), an inhibitor of autophagy, in LPS-mediated inflammatory responses and fibrosis. We collected AMs from observers/silicosis patients. The results showed that LPS induced NF-κB-related pulmonary inflammation in observers and silicosis patients, as confirmed by an increase in the expression of IL-1β, IL-6, TNF-α, and p65, which could be inhibited by 3-MA treatment. In mice models, at the early stage (7d) of silicosis, but not the late (28d) stage, blocking autophagy reversed the increased levels of IL-1β, IL-6, TNF-α, and p65 caused by LPS. Mechanism study revealed that LPS triggered the expression of LC3 II, p62, and cleaved caspase-3 at the early stage exposed to silica, which could be restored by 3-MA, while there was no difference in the expression of LAMP1 either at the early or late stage of silicosis in different groups. Similarly, 3-MA treatment did not prevent fibrosis characterized by destroyed alveoli, collagen deposition, and increased expression of α-SMA and Col-1 induced by LPS at the late stage of silicosis. The results suggested that 3-MA has a role in the protection of lung injury at the early stage of silicosis and provided an experimental basis for preventive strategies of pulmonary inflammation and silicosis. 10.1177/07482337211039426
The therapeutic effect of exosomal lncRNA MSTRG.91634.7 on mitochondrial dysfunction during SiO-induced lung fibrosis. International immunopharmacology Long-term silica (SiO) exposure led to irreversible lung fibrosis, in which epithelial-mesenchymal transition (EMT) played an essential role. A novel lncRNA MSTRG.91634.7 in the peripheral exosomes of silicosis patients was reported in our previous study, which could remold the pathological process of silicosis. However, whether its regulatory role on the development of silicosis was related to EMT process is unclear, and its mechanism remains to be further studied. In this study, up-regulating lncRNA MSTRG91634.7 restricted SiO-activated EMT and restored mitochondrial homeostasis binding to PINK1 in vitro. Moreover, overexpressing PINK1 could inhibit SiO-activated EMT in pulmonary inflammation and fibrosis in mice. Meanwhile, PINK1 contributed to restoring the SiO-induced mitochondrial dysfunction in mice lung. Our results revealed that exosomal lncRNA MSTRG.91634.7 from macrophages could restore mitochondrial homeostasis to restrict the SiO-activated EMT by binding to PINK1 during pulmonary inflammation and fibrosis due to SiO exposure. 10.1016/j.intimp.2023.110508
MSU Crystals induce sterile IL-1β secretion via P2X7 receptor activation and HMGB1 release. Marinho Ygor,Marques-da-Silva Camila,Santana Patricia Teixeira,Chaves Mariana Martins,Tamura Augusto Shuiti,Rangel Thuany Prado,Gomes-E-Silva Isabel Virgínia,Guimarães Marília Zaluar Passos,Coutinho-Silva Robson Biochimica et biophysica acta. General subjects BACKGROUD:The mechanism by which monosodium urate (MSU) crystals induce inflammation is not completely understood. Few studies have shown that MSU is capable of stimulating the release of IL-1β in the absence of LPS treatment. The purinergic P2X7 receptor is involved in the release of IL-1β in inflammatory settings caused by crystals, as is the case in silicosis. METHODS:We investigated the role of P2X7 receptor in sterile MSU-induced inflammation by evaluating peritonitis and paw edema. In in vitro models, we performed the experiments using peritoneal macrophages and THP-1 cells. We measured inflammatory parameters using ELISA and immunoblotting. We measured cell recruitment using cell phenotypic identification and hemocytometer counts. RESULTS:Our in vivo data showed that animals without P2X7 receptors generated less paw edema, less cell recruitment, and lower levels of IL-1β release in a peritonitis model. In the in vitro model, we observed that MSU induced dye uptake by the P2X7 receptor. In the absence of the receptor, or when it was blocked, MSU crystals induced less IL-1β release and this effect corresponded to the concentration of extracellular ATP. Moreover, MSU treatment induced HMGB1 release; pre-treatment with P2X7 antagonist reduced the amount of HMGB1 in cell supernatants. CONCLUSIONS:IL-1β secretion induced by MSU depends on P2X7 receptor activation and involves HMGB1 release. GENERAL SIGNIFICANCE:We propose that cell activation caused by MSU crystals induces peritoneal macrophages and THP-1 cells to release ATP and HMGB1, causing IL-1β secretion via P2X7 receptor activation. 10.1016/j.bbagen.2019.129461
In situ evidence of collagen V and signaling pathway of found inflammatory zone 1 (FIZZ1) is associated with silicotic granuloma in lung mice. Martins Vanessa,da Silva Adriana Lopes,Teodoro Walcy Rosolia,Velosa Ana Paula Pereira,Balancin Marcelo Luiz,Cruz Fernanda Ferreira,Silva Pedro Leme,Rocco Patrícia Rieken Macedo,Capelozzi Vera Luiza Pathology, research and practice Inhalation of silica particles causes silicosis: an occupational lung disease characterized by persistent inflammation with granuloma formation that leads to tissue remodeling and impairment of lung function. Although silicosis has been studied intensely, little is known about the crucial cellular mechanisms that initiate and drive the process of inflammation and fibrosis. Recently, found in inflammatory zone 1 (FIZZ1) protein, produced by alveolar macrophages and fibroblasts have been shown to induce the proliferation of myofibroblasts and their transdifferentiation, causing tissue fibrosis. Moreover, autoimmunogenic collagen V, produced by alveolar epithelial cells and fibroblasts, is involved in the pathophysiology of interstitial pulmonary fibrosis and bleomycin-induced lung fibrosis. Based on the aforementioned we hypothesized that FIZZ1 and collagen V may be involved in the silicotic granuloma process in mice lungs. Male C57BL/6 mice (N = 20) received intratracheal administration of silica particles (Silica; 20 mg in 50 μL saline) or saline (Control; 50 μL). After 15 days, the lung histology was performed through immunohistochemistry and morphometric analysis. Within silicotic granulomas, collagen V and FIZZ1 increased, while peroxisome proliferator-activated receptor gamma (PPARγ) positive cells decreased. In addition, the expression of proteins Notch-1, alpha smooth muscle actin (α-SMA) and macrophages163 (CD163) were higher in silicotic granulomas than control lungs. A significant positive correlation was found between collagen V and FIZZ1 (r = 0.70; p < 0.05), collagen V and Notch-1 (r = 0.72; p < 0.05), whereas Collagen V was inversely associated with peroxisome proliferator-activated receptor gamma (r=-0.69; p < 0.05). These findings suggested that collagen V association with FIZZ1, Notch-1 and PPARγ might be a key pathogenic mechanism for silicotic granulomas in mice lungs. 10.1016/j.prp.2020.153094
Profiling of the silica-induced molecular events in lung epithelial cells using the RNA-Seq approach. Chan Judy Y W,Tsui Joseph C C,Law Patrick T W,So Winnie K W,Leung Doris Y P,Sham Michael M K,Tsui Stephen K W,Chan Carmen W H Journal of applied toxicology : JAT Silicosis is a prolonged, irreversible and incurable occupational disease, and there is a significant number of newly diagnosed cases every year in Hong Kong. Due to the long latency of the disease, the diagnosis can be missed until detailed clinical examination at a later stage. For a better control of this deadly disease, detailing the pro-inflammatory and fibrotic events in the macrophage would be instrumental in understanding the pathogenesis of the disease and essential for the significant biomarkers discovery. In this in vitro study, human cell line model A549 lung epithelial cells were used. The immediate molecular events underneath the activation of quartz silica polymorphs were followed in a time course of 0, 0.5, 2, 8, 16 and 24 h. The transcriptome library was prepared and subjected to RNA-Seq analysis. Data analysis was performed by pathway analysis tools and verified by real-time PCR. The results showed that triggered genes were mainly found in the immune response and inflammatory pathways. An interesting finding was the association of the DNA-binding protein inhibitor (ID) family in the silica exposure to lung cells. The linkage of ID1, ID2 and ID3 to cancer may rationalize themselves to be the markers indicating an early response of silicosis. However, further studies are required to consolidate the roles of these genes in silicosis. Copyright © 2017 John Wiley & Sons, Ltd. 10.1002/jat.3471
CT/NIRF dual-modal imaging tracking and therapeutic efficacy of transplanted mesenchymal stem cells labeled with Au nanoparticles in silica-induced pulmonary fibrosis. Huang Jie,Huang Jie,Ning Xinyu,Luo Wei,Chen Mengling,Wang Zhangyan,Zhang Wei,Zhang Zhijun,Chao Jie Journal of materials chemistry. B Mesenchymal stem cells (MSCs) have shown promising therapeutic effects in cell-based therapies and regenerative medicine. Efficient tracking of MSCs is an urgent clinical need that will help us to understand their behavior after transplantation and allow adjustment of therapeutic strategies. However, no clinically approved tracers are currently available, which limits the clinical translation of stem cell therapy. In this study, a nanoparticle (NP) for computed tomography (CT)/fluorescence dual-modal imaging, Au@Albumin@ICG@PLL (AA@ICG@PLL), was developed to track bone marrow-derived mesenchymal stem cells (BMSCs) that were administered intratracheally into mice with silica-induced pulmonary fibrosis, which facilitated understanding of the therapeutic effect and the possible molecular mechanism of stem cell therapy. The AuNPs were first formed in bovine serum albumin (BSA) solution and modified with indocyanine green (ICG), and subsequently coated with a poly-l-lysine (PLL) layer to enhance intracellular uptake and biocompatibility. BMSCs were labeled with AA@ICG@PLL NPs with high efficiency without an effect on biological function or therapeutic capacity. The injected AA@ICG@PLL-labeled BMSCs could be tracked via CT and near-infrared fluorescence (NIRF) imaging for up to 21 days after transplantation. Using these NPs, the molecular anti-inflammatory mechanism of transplanted BMSCs was revealed, which included the downregulation of proinflammatory cytokines, suppression of macrophage activation, and delay of the fibrosis process. This study suggests a promising role for imaging-guided MSC-based therapy for pulmonary fibrosis, such as idiopathic pulmonary fibrosis (IPF) and pneumoconiosis. 10.1039/c9tb02652e
[Differential on N6-methyladenosine modification of circRNA in early inflammation of silicosis]. Luo W,Wang S,Li Y Q,Wang J,Yang S S,Chao J Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases To explore the difference of methylation of circRNA related m6A in early inflammation of silicosis and to elucidate the underlying molecular mechanism of circRNA involved in the process of silicosis. The activation markers of macrophages were detected by Western blotting (WB) in THP-1-derived macrophages. The cell viability was detected with CCK8, by which the stimulation concentration and time of silica were determined. The methylation of total RNA was determined by colorimetry, and the expression of RNA m6A methylase, demethylase and reading protein were detected by Western blotting in mouse model of silicosis. The differential expression of m6A modified circRNA in lung tissues form silicosis and control mice was obtained through Arraystar m6A circRNA epigenetic transcriptome Chip and verified by RT-PCR. The concentration of SiO(2) at 50 μg/cm(2) had the most significant effect on the activation markers and activity of macrophages. Compared with the control group, SiO(2) increased the total RNA m6A level of macrophages, and there were significant differences in the expression of methylase METTL3 and reading protein YTDHF3. High throughput sequencing analysis showed that compared with the control group, the methylation levels of 132 circRNA m6A in the lung of silicosis model mice were increased, while the methylation levels of 296 circRNA m6A were decreased, and then the target circSLC2A13 was screened based on the basic expression. Further verification showed that SiO(2) significantly increased the expression of circSLC2A13 and m6A modification in macrophages. The methylation of circRNA m6A is involved in the activation of macrophages in early inflammation of silicosis. 10.3760/cma.j.cn121094-20210312-00141
Impact of reactive iron in coal mine dust on oxidant generation and epithelial lung cell viability. Sun Yingying,Kinsela Andrew S,Cen Xiaotong,Sun Siqi,Collins Richard N,Cliff David I,Wu Yuxuan,Waite T David The Science of the total environment Coal workers' pneumoconiosis (CWP) is a preventable occupational lung disease caused by the chronic inhalation of coal mine dust. The inhalation of coal mine dusts can result in the development of a range of lung diseases termed coal mine dust lung diseases, which is not limited to CWP and includes silicosis, bronchitis, emphysema and cancer. For decades, the presence of elemental Fe, C and Si has been proposed to be the causal factors underlying CWP. The recent resurgence of CWP globally with examination of cases in the United States suggesting a potential but inconclusive role of Fe(II)-sulfide minerals. To obtain a better understanding of Australian coals, the existence and potential adverse impacts of iron minerals were examined using 24 representative Australian coal samples. The results of this work revealed that reduced iron minerals were widely distributed within samples obtained from Australian coal mines with pyrite and siderite being particularly abundant. Compared with carbon and crystalline silica, the presence of these specific iron minerals were negatively correlated to the viability of both alveolar macrophages (NR8383) and human lung epithelial cells (A549) (R = 0.689) under scenarios reflecting biologically-relevant inflammatory response conditions. Further analysis using Welch's unpaired t-test indicated that the presence of reduced iron minerals statistically enhanced acellular oxidant production (90% CI [0.74 to 2.55]) and inflammatory response (90% CI [0.15 to 36.96]). Compared with Fe(II)-hydroxide, Fe(II)- and Fe(III)-(phyllo)silicate and Fe(II)-sulfate mineralogies, pyrite and siderite bearing dusts are likely to have greater adverse impacts on epithelial lung cells under inflammatory response conditions in view of both their iron content and reactivity. 10.1016/j.scitotenv.2021.152277
Transcriptome analysis reveals a protective role of liver X receptor alpha against silica particle-induced experimental silicosis. Yao Wu,Yang Peiyan,Qi Yuanmeng,Jin Luheng,Zhao Ahui,Ding Mingcui,Wang Di,Li YiPing,Hao Changfu The Science of the total environment Silicosis, a severe and irreversible form of pulmonary fibrosis (PF) caused by long-term exposure to dust particles in production environments, is the biggest occupational health concern in China and most low-income countries. The transdifferentiation of pulmonary fibroblasts is the terminal event in silicosis, and specific transcription factors (TFs) play a crucial role in this condition. However, the relationship between TF-mediated regulation and silicosis remains unknown. We performed a transcriptomic analysis to elucidate this relationship, and our results revealed that two TFs, EGR2 and BHLHE40, were upregulated and five, i.e., TBX2, NR1H3 (LXRα), NR2F1, PPARG (PPARγ), and EPAS1, were downregulated in activated fibroblasts. Notably, PPARγ and LXRα expression was also decreased in an experimental mouse model of silicosis. The mechanism underlying these changes may involve TGF-β1 secretion from silica-exposed alveolar macrophages, causing PPARγ and LXRα downregulation, which in turn would result in aberrant α-SMA transcription. Our results suggest that LXRα is a potential target for the prevention of silicosis and PF. 10.1016/j.scitotenv.2020.141531
Trehalose Alleviates Crystalline Silica-Induced Pulmonary Fibrosis via Activation of the TFEB-Mediated Autophagy-Lysosomal System in Alveolar Macrophages. He Xiu,Chen Shi,Li Chao,Ban Jiaqi,Wei Yungeng,He Yangyang,Liu Fangwei,Chen Ying,Chen Jie Cells Silicosis is an occupational lung disease characterized by persistent inflammation and irreversible fibrosis. Crystalline silica (CS) particles are mainly phagocytized by alveolar macrophages (AMs), which trigger apoptosis, inflammation, and pulmonary fibrosis. Previously, we found that autophagy-lysosomal system dysfunction in AMs was involved in CS-induced inflammation and fibrosis. Induction of autophagy and lysosomal biogenesis by transcription factor EB (TFEB) nuclear translocation can rescue fibrotic diseases. However, the role of TFEB in silicosis is unknown. In this study, we found that CS induced TFEB nuclear localization and increased TFEB expression in macrophages both in vivo and in vitro. However, TFEB overexpression or treatment with the TFEB activator trehalose (Tre) alleviated lysosomal dysfunction and enhanced autophagic flux. It also reduced apoptosis, inflammatory cytokine levels, and fibrosis. Both pharmacologically inhibition of autophagy and TFEB knockdown in macrophages significantly abolished the antiapoptotic and anti-inflammatory effects elicited by either TFEB overexpression or Tre treatment. In conclusion, these results uncover a protective role of TFEB-mediated autophagy in silicosis. Our study suggests that restoration of autophagy-lysosomal function by Tre-induced TFEB activation may be a novel strategy for the treatment of silicosis. 10.3390/cells9010122
Differential immunological effects of silica nanoparticles on peripheral blood mononuclear cells of silicosis patients and controls. Frontiers in immunology Silicosis is a fibrotic disease caused by the inhalation of respirable silica particles, which are typically engulfed by alveolar macrophages and subsequently induce the release of inflammatory cytokines. Various animal experimental and human studies have focused on modeling silicosis, to assess the interactions of macrophages and other cell types with silica particles. There is still, however, limited knowledge on the differential response upon silica-exposure between silicosis patients and controls. We focused on studying the responsiveness of peripheral blood mononuclear cells (PBMCs) to silica nanoparticles (SiNPs) - Ludox and NM-200 - of silicosis patients and controls. The proliferative capacity of T- CD3 and B- CD19 cells, were evaluated Carboxyfluorescein succinimidyl ester (CFSE) assay. The activation status of lymphocyte subsets and response to silica were also evaluated by comparing the extent of micro-granuloma or aggregate formation with the cytokine secretion profiles between both groups of individuals. The proliferative capacity of CD19 cells was elevated in silicotic patients as opposed to controls. Subsets of regulatory T cells (CD4 CD25 and CD8 CD25) and immunoglobulins IgM and IgG were also significantly increased in patients. The number and the size of aggregates formed were higher with SiNPs stimulation in patients compared to controls. Multivariable analysis also elucidated the role of key cytokines like interleukin-1β (IL-1β), IL-6 and interferon-gamma (IFN-γ), which were upregulated in SiNP-stimulated PBMCs of patients compared to controls. Our model thus has potential to provide insights into the immunological effects of silica particles in lymphocytes of silicosis patients and controls. 10.3389/fimmu.2022.1025028
Therapeutic effects of bone marrow-derived mononuclear cells from healthy or silicotic donors on recipient silicosis mice. de Oliveira Helena D'Anunciação,de Melo Elga Bernardo Bandeira,Silva Johnatas Dutra,Kitoko Jamil Zola,Gutfilen Bianca,Barboza Thiago,de Souza Sergio Augusto Lopes,Takiya Christina Maeda,Rocco Patricia Rieken Macedo,Lopes-Pacheco Miquéias,Morales Marcelo Marcos Stem cell research & therapy BACKGROUND:Administration of bone marrow mononuclear cells (BMMCs) modulates lung inflammation and fibrosis in experimental silicosis. However, no studies have evaluated whether silicosis affects the efficacy of autologous BMMCs treatment. We hypothesized that BMMCs obtained from healthy or silicotic mice may improve lung function, but they might affect the inflammatory and fibrotic processes differently in experimental silicosis. METHODS:C57BL/6 mice were randomly divided into control (C) and silicosis (SIL) groups. Mice in the SIL group were instilled with silica particles intratracheally; the C animals received saline using the same protocol. On day 15, the animals were treated with saline (Sal) or BMMCs (2 × 10 cells) from healthy (BMMC-healthy) and silicotic (BMMC-sil) donors. Lung mechanics were measured, and lungs were collected for histology and molecular biology analysis. RESULTS:BMMCs obtained from healthy and silicotic donors presented similar percentages of cell populations. Tc-BMMCs tracking revealed preferential migration of cells to the liver, and only a few GFP BMMCs were observed in lung tissue 24 h after treatment, regardless of donor type. Both the SIL-BMMC-healthy and SIL-BMMC-sil groups showed improvement in lung function, a reduction in the fractional area of granuloma, and a decrease in the number of mononuclear and apoptotic cells in lung parenchyma. In addition, the number of F4/80 macrophages, the levels of interleukin-1 beta and transforming growth factor beta, and collagen fiber content in granuloma were reduced in SIL-BMMC-healthy mice, whereas mRNA expression of MMP-9 and procollagen I and III was reduced in the SIL-BMMC-sil group. CONCLUSIONS:Administration of BMMCs from healthy and silicotic donors reduced lung inflammation and fibrosis, thus improving lung function. In addition, BMMC-healthy exhibited a greater improvement in lung morpho-functional changes in murine model of silicosis. 10.1186/s13287-017-0699-7
Follistatin like-1 aggravates silica-induced mouse lung injury. Scientific reports Occupational inhalation of dust, such as crystalline silica, for prolonged periods in the workplace leads to fibrotic lung diseases worldwide. The mechanisms underlying the diseases are unknown, so that no effective treatment exists for these conditions. We found elevated levels of follistatin like 1 (FSTL1) in serum from patients with silicosis and in lungs from silica-induced mouse model. The induced Fstl1 regulated inflammation response via activation of nod-like receptor family, pyrin domain containing 3v (NLRP3) inflammasome-mediated IL-1β production from macrophages. Meanwhile, Fstl1 promoted fibrosis via positive regulation of TGF-β1 signaling. Haploinsufficiency of Fstl1 or blockage of FSTL1 with a neutralizing antibody was protective from silica-induced lung injury in mice in vivo. Our data suggest that Fstl1 plays an important role in lung fibrosis, and may serve as a novel therapeutic target for treatment of silicosis. 10.1038/s41598-017-00478-0
Extracellular cathepsin Z signals through the α integrin and augments NLRP3 inflammasome activation. The Journal of biological chemistry Respiratory silicosis is a preventable occupational disease that develops secondary to the aspiration of crystalline silicon dioxide (silica) into the lungs, activation of the NLRP3 inflammasome, and IL-1β production. Cathepsin Z has been associated with the development of inflammation and IL-1β production; however, the mechanism of how cathepsin Z leads to IL-1β production is unknown. Here, the requirement for cathepsin Z in silicosis was determined using WT mice and mice deficient in cathepsin Z. The activation of the NLRP3 inflammasome in macrophages was studied using WT and cathepsin Z-deficient bone marrow-derived murine dendritic cells and the human monocytic cell line THP-1. The cells were activated with silica, and IL-1β release was determined using enzyme-linked immunosorbent assay or IL-1β bioassays. The relative contribution of the active domain or integrin-binding domain of cathepsin Z was studied using recombinant cathepsin Z constructs and the α integrin neutralizing antibody. We report that the lysosomal cysteine protease cathepsin Z potentiates the development of inflammation associated with respiratory silicosis by augmenting NLRP3 inflammasome-derived IL-1β expression in response to silica. The secreted cathepsin Z functions nonproteolytically via the internal integrin-binding domain to impact caspase-1 activation and the production of active IL-1β through integrin α without affecting the transcription levels of NLRP3 inflammasome components. This work reveals a regulatory pathway for the NLRP3 inflammasome that occurs in an outside-in fashion and provides a link between extracellular cathepsin Z and inflammation. Furthermore, it reveals a level of NLRP3 inflammasome regulation that has previously only been found downstream of extracellular pathogens. 10.1016/j.jbc.2021.101459
5-Aminosalicylic Acid Modulates the Immune Response in Chronic Beryllium Disease Subjects. Day Brian J,Huang Jie,Barkes Briana Q,Gillespie May,Li Li,Maier Lisa A Lung INTRODUCTION:Chronic beryllium disease (CBD) is characterized by accumulation of macrophages and beryllium-specific CD4 T cells that proliferate and produce Th1 cytokines. 5-Amino salicylic acid (5-ASA) is currently used to treat inflammatory bowel disease and has both antioxidant and anti-inflammatory actions. We hypothesized that 5-ASA may be a beneficial therapeutic in CBD. METHODS:Seventeen CBD patients were randomized 3:1 to receive 5-ASA 500-mg capsules or placebo four times daily for 6 weeks orally. Primary study endpoints included changes in beryllium lymphocyte proliferation (BeLPT). Secondary endpoints included changes in bronchoalveolar lavage (BAL) fluid, cells, serum, and blood cell glutathione (GSH) levels, BAL cell TNF-α levels, lung function, and quality of life measures. RESULTS:5-ASA decreased BAL cell BeLPT by 20% within the 5-ASA treatment group. No significant changes were observed in serum, PBMCs, BALF, or BAL cell GSH levels in either the 5-ASA or placebo treatment group. 5-ASA treatment decreased ex vivo Be-stimulated BAL cell TNF-α levels within the 5-ASA group and when compared to placebo. Significant improvements were noted in quality of life measurements with 5-ASA treatment. CONCLUSIONS:5-ASA's ability to decrease BAL cell BeLPT and Be-stimulated BAL cell TNF-α levels suggests that 5-ASA may impact the beryllium-specific immune response in CBD. 5-ASA use in other non-infectious granulomatous lung diseases, such as sarcoidosis, may prove to be a useful alternative treatment to corticosteroids for those with mild to moderate disease. 10.1007/s00408-017-0062-x
Silica dust exposure induces autophagy in alveolar macrophages through switching Beclin1 affinity from Bcl-2 to PIK3C3. Yang Pan,Song Ruirui,Li Ning,Sun Kun,Shi Fan,Liu Heliang,Shen Fuhai,Jiang Shoufang,Zhang Lin,Jin Yulan Environmental toxicology Increased deposition of silica dust in pulmonary interstitial tissues leads to silicosis, in which autophagy plays a defensive role in silica dust-associated stress response and cell death. Our previous studies revealed that silica dust exposure contributed to autophagy in pulmonary macrophages in vivo, while the specific regulatory mechanism is still unclear. This study aimed to figure out the regulatory mechanism as well as the role of autophagy in the pathogenesis of experimental silicosis. We used 3-methyladenine (3-MA) and ABT-737 to suppress the expression of phosphatidylinositol 3-kinase catalytic subunit type 3 (PIK3C3) and B cell leukemia/lymphoma 2 (Bcl-2), two critical initiators of autophagy, and detected and evaluated the autophagy in NR8383 cells with or without silica dust exposure. We found that exposure of silica dust increased autophagy in NR8383 cells and elevated the expression of Beclin1 and PIK3C3, but it reduced the expression of Bcl-2. The relationship among Beclin1, PIK3C3, and Bcl-2 were then investigated using immunoprecipitation analysis, and we found that suppression of PIK3C3 and/or Bcl-2 using 3-MA and/or ABT-737 could alter the autophagy induced by silica dust in NR8383 cells, and the complexes of Beclin1/PIK3C3 and Beclin1/Bcl-2 were both downregulated, which may be that inhibition of PIK3C3 and Bcl-2 altered the affinity of Beclin1 with PIK3C3 and Bcl-2 and lead to the silence of PIK3C3 signaling. These findings indicate that silica dust exposure induces autophagy via changing the connectivity of Beclin1 from Bcl-2 to PIK3C3. 10.1002/tox.22910
TLR9 and IL-1R1 Promote Mobilization of Pulmonary Dendritic Cells during Beryllium Sensitization. Wade Morgan F,Collins Morgan K,Richards Denay,Mack Douglas G,Martin Allison K,Dinarello Charles A,Fontenot Andrew P,McKee Amy S Journal of immunology (Baltimore, Md. : 1950) Metal-induced hypersensitivity is driven by dendritic cells (DCs) that migrate from the site of exposure to the lymph nodes, upregulate costimulatory molecules, and initiate metal-specific CD4 T cell responses. Chronic beryllium disease (CBD), a life-threatening metal-induced hypersensitivity, is driven by beryllium-specific CD4 Th1 cells that expand in the lung-draining lymph nodes (LDLNs) after beryllium exposure (sensitization phase) and are recruited back to the lung, where they orchestrate granulomatous lung disease (elicitation phase). To understand more about how beryllium exposures impact DC function during sensitization, we examined the early events in the lung and LDLNs after pulmonary exposure to different physiochemical forms of beryllium. Exposure to soluble or crystalline forms of beryllium induced alveolar macrophage death/release of IL-1α and DNA, enhanced migration of CD80 DCs to the LDLNs, and sensitized HLA-DP2 transgenic mice after single low-dose exposures, whereas exposures to insoluble particulate forms beryllium did not. IL-1α and DNA released by alveolar macrophages upregulated CD80 on immature BMDC via IL-1R1 and TLR9, respectively. Intrapulmonary exposure of mice to IL-1R and TLR9 agonists without beryllium was sufficient to drive accumulation of CD80 DCs in the LDLNs, whereas blocking both pathways prevented accumulation of CD80 DCs in the LDLNs of beryllium-exposed mice. Thus, in contrast to particulate forms of beryllium, which are poor sensitizers, soluble or crystalline forms of beryllium promote death of alveolar macrophages and their release of IL-1α and DNA, which act as damage-associated molecular pattern molecules to enhance DC function during beryllium sensitization. 10.4049/jimmunol.1800303
Exercise training inhibits macrophage-derived IL-17A-CXCL5-CXCR2 inflammatory axis to attenuate pulmonary fibrosis in mice exposed to silica. The Science of the total environment Exposure to crystalline silica leads to health effects beyond occupational silicosis. Exercise training's potential benefits on pulmonary diseases yield inconsistent outcomes. In this study, we utilized experimental silicotic mice subjected to exercise training and pharmacological interventions, including interleukin-17A (IL-17A) neutralizing antibody or clodronate liposome for macrophage depletion. Findings reveal exercise training's ability to mitigate silicosis progression in mice by suppressing scavenger receptor B (SRB)/NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and Toll-like receptor 4 (TLR4) pathways. Macrophage-derived IL-17A emerges as primary source and trigger for silica-induced pulmonary inflammation and fibrosis. Exercise training effectively inhibits IL-17A-CXC motif chemokine ligand 5 (CXCL5)-Chemokine (C-X-C motif) Receptor 2 (CXCR2) axis in silicotic mice. Our study evidences exercise training's potential to reduce collagen deposition, preserve elastic fibers, slow pulmonary fibrosis advancement, and enhance pulmonary function post silica exposure by impeding macrophage-derived IL-17A-CXCL5-CXCR2 axis. 10.1016/j.scitotenv.2023.166443
Emodin attenuates silica-induced lung injury by inhibition of inflammation, apoptosis and epithelial-mesenchymal transition. International immunopharmacology Silicosis is a fatal pulmonary disease caused by the inhalation of silica dust, and characterized by inflammation and fibrosis of the lung, with no effective treatment to date. Here we investigate the effect of emodin, an anthraquinone derivative isolated from rhubarb using a mouse silicosis model and in vitro cultured human macrophages and alveolar epithelial cells. Results from histological examination indicated that emodin reduced the degree of alveolitis and fibrosis in the lungs of mice exposed to silica particles. We also demonstrated that emodin effectively inhibited the phosphorylation of Smad3 and NF-κB and reduced the levels of inflammatory factors in the lung tissue of mice treated with silica particles. In addition, we found that emodin inhibited apoptosis and demonstrated an anti-fibrotic effect by down-regulating the pro-apoptotic protein Bax and up-regulating the anti-apoptotic protein Bcl-2. Furthermore, emodin increased E-cadherin levels, reduced the expression of Vimentin, α-SMA and Col-I, as well as pro-inflammatory factors TGF-β1, TNF-α and IL-1β in vivo and in vitro. These results suggested that emodin can regulate epithelial-mesenchymal transition (EMT) through the inhibition of the TGF-β1/Smad3 signaling pathway and the NF-κB signaling pathway to prevent alveolar inflammation and apoptotic process. Overall, this study showed that emodin can alleviate pulmonary fibrosis in silicosis through regulating the inflammatory response and fibrotic process at multiple levels. 10.1016/j.intimp.2020.107277
A role for TNF-α in alveolar macrophage damage-associated molecular pattern release. Collins Morgan K,Shotland Abigail M,Wade Morgan F,Atif Shaikh M,Richards Denay K,Torres-Llompart Manolo,Mack Douglas G,Martin Allison K,Fontenot Andrew P,McKee Amy S JCI insight Chronic beryllium disease (CBD) is a metal hypersensitivity/autoimmune disease in which damage-associated molecular patterns (DAMPs) promote a break in T cell tolerance and expansion of Be2+/self-peptide-reactive CD4+ T cells. In this study, we investigated the mechanism of cell death induced by beryllium particles in alveolar macrophages (AMs) and its impact on DAMP release. We found that phagocytosis of Be led to AM cell death independent of caspase, receptor-interacting protein kinases 1 and 3, or ROS activity. Before cell death, Be-exposed AMs secreted TNF-α that boosted intracellular stores of IL-1α followed by caspase-8-dependent fragmentation of DNA. IL-1α and nucleosomal DNA were subsequently released from AMs upon loss of plasma membrane integrity. In contrast, necrotic AMs released only unfragmented DNA and necroptotic AMs released only IL-1α. In mice exposed to Be, TNF-α promoted release of DAMPs and was required for the mobilization of immunogenic DCs, the expansion of Be-reactive CD4+ T cells, and pulmonary inflammation in a mouse model of CBD. Thus, early autocrine effects of particle-induced TNF-α on AMs led to a break in peripheral tolerance. This potentially novel mechanism may underlie the known relationship between fine particle inhalation, TNF-α, and loss of peripheral tolerance in T cell-mediated autoimmune disease and hypersensitivities. 10.1172/jci.insight.134356
Prevention of crystalline silica-induced inflammation by the anti-malarial hydroxychloroquine. Burmeister Rachel,Rhoderick Joseph F,Holian Andrij Inhalation toxicology Inhalation of crystalline silica (cSiO) remains a significant occupational hazard and may lead to the development of silicosis. When cSiO particles are phagocytized by alveolar macrophages, they cause disruption of the lysosomal membrane which results in cell death. There are currently no pharmaceutical treatments directed at this mechanism of disease; however, many existing pharmaceuticals, such as hydroxychloroquine (HCQ), become sequestered in the lysosome through an ion-trapping mechanism. The objective of this research was to determine whether HCQ can prevent cSiO-induced toxicity by blocking LMP in alveolar macrophages. This study assessed the ability of treatment with HCQ to block toxicity and lysosomal membrane permeability in cSiO-exposed mouse bone-marrow derived macrophages. Additionally, C57Bl/6 mice were treated with HCQ by oral gavage before cSiO exposure, and the ability of HCQ to prevent lung injury and inflammation was assessed. studies demonstrated that HCQ attenuated activation of the NLRP3 inflammasome and blocked LMP. Mice treated with HCQ showed a modest trend towards decreased cSiO-induced toxicity. culture of alveolar macrophages collected from cSiO-treated mice showed significantly less NLRP3 inflammasome activation after exposure to HCQ. Our findings suggest that hydroxychloroquine blocks LMP and can significantly decrease cSiO-induced toxicity . HCQ may be a promising treatment for prevention of cSiO-induced lung damage. 10.1080/08958378.2019.1668091
TNFR/TNF-α signaling pathway regulates apoptosis of alveolar macrophages in coal workers' pneumoconiosis. Oncotarget We explored the role of TNFR/TNF-α signalingin apoptosis among alveolar macrophages (AM) and its relevance to the development of coal workers' pneumoconiosis (CWP). Purified alveolar macrophages (AMs) were prepared from bronchoalveolar lavage fluid harvested from 366 CWP patients and 120 healthy subjects enrolled inthe study. The purified AMs were then divided into control, SOD, anti-TNFR, TNFR and NFkB inhibitor groups and analyzed for apoptosis usingflow cytometry (sub-diploid peak) and western blotting (Bcl-2, Caspase-3 and Caspase-8 expression). We found thatAM apoptosis washigher amongCWP patients than thehealthycontrols. Expression ofBcl-2, Caspase-3 and Caspase-8 was higher inAMs from CWP patientsthan in those from the controlsand correlated with increased AM apoptosis. Univariate and multivariate analyses suggested that CWP grade, initial exposure time, exposure time inyears, and CWP onset agewereall associated with altered levels of Bcl-2, Caspase-3 and Caspase-8. Inhibition of TNFR/TNF-α signaling usinganti-TNFR antibody, SOD or NFkB inhibitionreduced AM apoptosisand decreased Bcl-2, Caspase-3 and Caspase-8 expression. These data suggestinhibition of a TNFR/TNF-α signaling pathway is a potentiallyeffective means ofalleviating CWP by inhibiting AM apoptosis. 10.18632/oncotarget.18921
Bioinformatics methods for identifying differentially expressed genes and signaling pathways in nano-silica stimulated macrophages. Zhang Lin,Hao Changfu,Li Juan,Qu Yaqian,Bao Lei,Li Yiping,Yue Zhongzheng,Zhang Miao,Yu Xinghao,Chen Huiting,Zhang Jianhui,Wang Di,Yao Wu Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine The incidence of disease relating to nanoparticle exposure has been rising rapidly in recent years, for which there is no effective treatment. Macrophage is suggested to play a crucial role in the development of pulmonary disease. To investigate the changes in macrophage after being stimulated by nanometer silica dust and to explore potential biomarkers and signaling pathways, the gene chip GSE13005 was downloaded from Gene Expression Omnibus database, which contained 21 samples: 3 samples per group and 7 groups in total. Macrophages in the control group were cultured in serum-free medium, while the experimental groups were treated with nanometer silica dust in different sizes and concentrations, respectively. To identify the differentially expressed genes and explore their potential functions, we adopted the gene ontology analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis and also constructed protein-protein interaction network. As a result, 1972 differentially expressed genes were identified from 22,690 microarray data in the gene chip, 1069 genes were upregulated and 903 genes were downregulated. Results of the gene ontology analysis indicated that the differentially expressed genes were widely distributed in intracellular and extracellular regions, regulating macrophage apoptosis, inflammatory response, and cell differentiation. The Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that the majority of differentially expressed genes were enriched in cytokine-cytokine receptor interaction, cancer or phagosome transcriptional misregulation. The top 10 hub genes, S100a9, Nos3, Psmd14, Psmd4, Lck, Atp6v1h, Jun, Foxh1, Pex14, and Fadd were identified from protein-protein interaction network. In addition, Nos3, Psmd14, Atp6v1h, and Jun were clustered into module M2 (r = 0.74, p < 0.01), which mainly regulates cell carcinogenesis and antivirus process. In conclusion, differentially expressed genes screened from this study may provide new insights into the exploration of mechanisms, biomarkers, and therapeutic targets for diseases relating to nanoparticle exposure. 10.1177/1010428317709284
Identification of circRNA expression profiles and the potential role of hsa_circ_0006916 in silicosis and pulmonary fibrosis. Toxicology Circular RNAs (circRNAs) are emerging as novel regulators in the biological development of various diseases, but their expression profiles, functions and mechanisms in silicosis and pulmonary fibrosis remain largely unexplored. In this study, we constructed a mouse model of pulmonary fibrosis by intratracheal injection of silica particles and then performed transcriptome RNA sequencing of lung tissues. The results showed that 78 circRNAs, 39 miRNAs and 262 mRNAs were differentially expressed. Among them, five circRNAs, three miRNAs and four mRNAs were further selected, and their abnormal expression was verified in mouse fibrotic lung tissues by RT-qPCR assay. The circRNA-associated ceRNA network including 206 ceRNA triplets was constructed based on abnormally expressed circRNAs, miRNAs and mRNAs, and miR-199b-5p, miR-296-5p and miR-708-5p were identified as hub miRNAs connected to circRNAs and mRNAs. Subsequently, GO and KEGG pathway enrichment analyses were performed to detect the potential roles of differentially expressed mRNAs in pulmonary fibrosis, which were mainly involved in immune response, Th17 cell differentiation, NF-κB signaling pathway and PI3K-Akt signaling pathway. Furthermore, we identified that hsa_circ_0006916 was up-regulated in pulmonary fibrosis. To characterize the potential role of hsa_circ_0006916, we transfected siRNA targeting hsa_circ_0006916 into alveolar macrophages and found that knockdown of hsa_circ_0006916 significantly increased the expression levels of M1 molecules IL-1β and TNF-α and reduced the expression level of M2 molecule TGF-β1, indicating that hsa_circ_0006916 may play an important role in the activation of M1-M2 polarization effect in macrophages. Our results provided important evidence on the possible contribution of these abnormal circRNAs to the development of silicosis and pulmonary fibrosis. 10.1016/j.tox.2022.153384
Alveolar macrophage-derived progranulin mediated pro-inflammatory Il-6 expression via regulating Creb1 in silicosis model. International immunopharmacology Progranulin (PGRN) is a secreted factor involved in inflammatory diseases. However, the function of PGRN in silica-induced lung inflammation has not been elucidated. In this study, we demonstrated that PGRN in serum and lung tissues was markedly increased in silicosis mouse model. And immunohistochemistry results showed that PGRN was mainly expressed in alveolar macrophages, which was further confirmed in silica-treated alvelar macrophages cell line (MH-S) in vitro. PGRN promoted pro-inflammatory cytokines transcription such as interleukin (Il)-6, tumor necrosis factor-α (Tnf-α) and Il-1β in MH-S cells, and the increasing of Il-6 was most obvious. Knockdown of PGRN blocked the silica-induced elevation of intracellular Il-6 in MH-S cells. Furthermore, we also found that PGRN could increase the phosphorylation of Cyclic AMP-responsive element-binding protein 1 (Creb1), a transcriptional regulator of Il-6. Inhibition of p-Creb1 by the phosphorylation inhibitor of Creb1 (666-15) decreased PGRN-induced intracellular Il-6 production in MH-S cells. In conclusion, PGRN was highly increased in silicosis mouse model and upregulated inflammatory cytokines expression. These findings suggested that PGRN might be a key mediator in silica-induced inflammation and provided a new clue for the diagnosis and drug therapy of silicosis. 10.1016/j.intimp.2022.108705
RAB20 deficiency promotes the development of silicosis NLRP3 inflammasome. Frontiers in immunology Silicosis is a worldwide serious occupational disease that is caused by inhalation of silica crystals. However, little is known about the pathogenesis mechanism of silicosis. We performed single-cell sequencing in bronchoalveolar lavage fluid (BALF) from mine workers with silicosis and their co-workers who did not develop silicosis, and found that the RAB20 deficiency in monocytes/macrophages was strongly linked to the development of silicosis. In the silicosis murine model, RAB20 knockout markedly enhanced the silica crystal-induced pulmonary interstitial fibrosis and respiratory dysfunction. Moreover, this process is strongly accompanied by IL-1β release and NLRP3 activation. , RAB20 knockout macrophages aggravated the crystalline silica-induced IL-1β release and NLRP3 inflammasome activation partly by increased ratio of crystalline silica/phagosomal areas/volumes to induce lysosomal injury. Thus, these findings provide novel molecular insights into the intricate mechanisms underlying lysosomal protein RAB20 that are necessary for environmental irritant-mediated innate immunity, and shed light on the future development of novel therapy target for the prevention of silicosis. 10.3389/fimmu.2022.967299
Clinical significance of CC16 and IL-12 in bronchoalveolar lavage fluid of various stages of silicosis. Annals of palliative medicine BACKGROUND:Identification of novel biomarkers for silicosis could be helpful for disease diagnosis and pathophysiological mechanism exploration. Our study aims to investigate the Clara cell secretory 16-kd protein (CC16) and interleukin-12 (IL-12) levels in bronchoalveolar lavage fluid (BALF) in patients with silicosis at various stages. METHODS:The enzyme-linked immunosorbent assay (ELISA) double antibody sandwich method was used to determine the CC16 and IL-12 in BALF levels from 79 patients with silicosis of various stages. Correlation analyses were performed between CC16 and IL-12 levels, and lung function and cytological counts in patients with silicosis at various stages. RESULTS:There were no significant differences in the BALF recovery volume, the number of cells, percentages of macrophages and lymphocytes in the alveolar lavage fluid of patients with silicosis in different stages (P>0.05); the percentage of neutrophils in stage I and stage II were higher than the control group (P<0.05) with statistically significant differences. The CC16 in BALF levels in stage I and II silicosis groups lower than the control group and stage III silicosis group with statistically significant differences (P<0.05), whereas CC16 levels in stage II silicosis group are higher than the stage I group (P<0.01). The IL-12 levels were higher than the control group (P<0.01), and the IL-12 levels in stage II and III silicosis group was higher than the stage I silicosis group (P<0.01). With the increase of the length of dust service, the CC16 and IL-12 levels decreased and showed a positive correlation between these indexes (correlation coefficient r=0.559, P<0.01). In addition, CC16 silicosis patient levels were positively correlated with FEV1/FVC and VCmax (r=0.242, 0.257; both P<0.05); IL-12 levels were negatively correlated with FEV1 and VC max (r=-0.250, -0.483; both P<0.05). CONCLUSIONS:The CC16 and IL-12 levels may have a specific reference value for the early diagnosis of silicosis and the assessment of lung function. 10.21037/apm-20-1838
The role of annexin A1 in the modulation of the NLRP3 inflammasome. Galvão Izabela,de Carvalho Renan V H,Vago Juliana P,Silva Alexandre L N,Carvalho Toniana G,Antunes Maísa M,Ribeiro Fabiola M,Menezes Gustavo B,Zamboni Dario S,Sousa Lirlândia P,Teixeira Mauro M Immunology Annexins are well-known Ca phospholipid-binding proteins, which have a wide variety of cellular functions. The role of annexin A1 (AnxA1) in the innate immune system has focused mainly on the anti-inflammatory and proresolving properties through its binding to the formyl-peptide receptor 2 (FPR2)/ALX receptor. However, studies suggesting an intracellular role of AnxA1 are emerging. In this study, we aimed to understand the role of AnxA1 for interleukin (IL)-1β release in response to activators of the nucleotide-binding domain leucine-rich repeat (NLR) and pyrin domain containing receptor 3 (NLRP3) inflammasome. Using AnxA1 knockout mice, we observed that AnxA1 is required for IL-1β release in vivo and in vitro. These effects were due to reduction of transcriptional levels of IL-1β, NLRP3 and caspase-1, a step called NLRP3 priming. Moreover, we demonstrate that AnxA1 co-localize and directly bind to NLRP3, suggesting the role of AnxA1 in inflammasome activation is independent of its anti-inflammatory role via FPR2. Therefore, AnxA1 regulates NLRP3 inflammasome priming and activation in a FPR2-independent manner. 10.1111/imm.13184
ZC3H4 regulates infiltrating monocytes, attenuating pulmonary fibrosis through IL-10. Respiratory research Silicosis is a pulmonary fibrosis-associated disease caused by the inhalation of large amounts of free silicon dioxide (SiO) that mainly manifests as early inflammation and late pulmonary fibrosis. As macrophage precursors, monocytes accumulate in the lung during early inflammation, but their role in the development of silicosis is unclear. Single-cell sequencing (cell numbers = 25,002), Western blotting, quantitative real-time PCR, ELISA and cell functional experiments were used to explore the specific effects of monocytes on fibroblasts. The CRISPR/Cas9 system was used to specifically knock down ZC3H4, a novel member of the CCCH zinc finger protein family, and was combined with pharmacological methods to explore the mechanism by which ZC3H4 affects chemokine and cytokine secretion. The results indicated that (1) SiO induced an infiltrating phenotype in monocytes; (2) infiltrating monocytes inhibited the activation, viability and migration of fibroblasts by regulating IL-10 but not IL-8; and (3) SiO downregulated IL-10 via ZC3H4-induced autophagy. This study revealed that ZC3H4 regulated the secretion function of monocytes, which, in turn, inhibited fibroblast function in early inflammation through autophagy signaling, thereby reducing pulmonary fibrosis. These findings provide a new idea for the clinical treatment of silicosis. 10.1186/s12931-022-02134-2
The role of macrophages in interstitial lung diseases: Number 3 in the Series "Pathology for the clinician" Edited by Peter Dorfmüller and Alberto Cavazza. European respiratory review : an official journal of the European Respiratory Society The finding of collections of macrophages/histiocytes in lung biopsy and bronchoalveolar lavage is relatively common in routine practice. This morphological feature in itself is pathological, but the exact clinical significance and underlying disease should be evaluated together with clinical data, functional respiratory and laboratory tests and imaging studies.Morphological characteristics of macrophages and their distribution along the different pulmonary structures should be examined carefully by pathologists. Indeed, haemosiderin-laden macrophages are associated with smoking-related diseases when pigment is fine and distribution is bronchiolocentric, while alveolar haemorrhage or pneumoconiosis are the main concerns when pigment is chunky or coarse and the macrophages show an intra-alveolar or perilymphatic location, respectively. In the same way, pulmonary accumulation of macrophages with foamy cytoplasm is generally associated with pathologies leading to broncho-bronchiolar obstruction ( diffuse panbronchiolitis, hypersensitivity pneumonia or cryptogenic organising pneumonia) or alternatively to exogenous lipoid pneumonia, some drug toxicity ( amiodarone exposure or toxicity) and metabolic disorders ( type B Niemann-Pick disease).This pathology-based perspectives article is aimed at concisely describing the diagnostic possibilities when faced with collection of macrophages in lung biopsy and cytology. 10.1183/16000617.0009-2017
lncRNA MIR155HG Accelerates the Progression of Sepsis via Upregulating MEF2A by Sponging miR-194-5p. Zhang Chao,Li Jing,Li Hongjing,Wang Guiling,Wang Qingqing,Zhang Xin,Li Baiteng,Xu Haixu DNA and cell biology Long noncoding RNA MIR155HG exerts important effects in the progression of multiple diseases. This study investigated the functions of MIR155HG in sepsis development. Blood samples were collected from 28 patients with sepsis and 28 without sepsis. The murine cardiac muscle cell line (HL-1) and macrophage cell line (RAW 264.7) treated with lipopolysaccharide (LPS) were used as the sepsis models. The levels of MIR155HG, miR-194-5p, and MEF2A were determined using real-time-quantitative polymerase chain reaction. Cell counting kit-8 and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assays were used to assess cell viability and apoptosis, respectively. The association between miR-194-5p and MIR155HG or MEF2A was confirmed using a dual-luciferase reporter assay. The levels of inflammatory cytokines were detected using enzyme-linked immunosorbent assay (ELISA). In this study, we demonstrated that MIR155HG expression was significantly increased in sepsis blood samples, RAW 264.7, and HL-1 cells treated with LPS. Silencing of MIR155HG promoted cell viability and obstructed cell apoptosis and inflammation of RAW 264.7 and HL-1 cells treated with LPS. MiR-194-5p depletion abrogated cell viability promotion and suppressive effect on cell apoptosis and inflammation caused by MIR155HG knockdown. In addition, MIR155HG upregulated MEF2A through interaction with miR-194-5p. Finally, rescue assays indicated that MEF2A overexpression abolished the inhibitory effect on sepsis progression induced by MIR155HG deletion. In conclusion, MIR155HG promotes sepsis progression in an sepsis model by modulating the miR-194-5p/MEF2A axis. This discovery provides a promising biomarker for sepsis therapy. 10.1089/dna.2021.0038
Anti‑fibrotic effects and the mechanism of action of miR‑29c in silicosis. Molecular medicine reports Despite increasing evidence suggesting a role for the miR‑29 family in the suppression of fibrosis, its role in silicosis remains unknown. The present study aimed to examine the anti‑fibrotic effects and specific mechanism of action of microRNA (miR)‑29c in pulmonary silicosis using animal and cell models. miR‑29c expression levels were examined in the lungs of silicotic rats via reveres transcription‑quantitative (RT‑q)PCR. A Transwell system employing co‑cultures of pulmonary fibroblasts and macrophages was used to establish an cell model of silicosis, and lentivirus was used to overexpress or knockdown miR‑29c in cultured cells. Changes in collagen type I α I (COL1α1), COL3α1, α‑smooth muscle actin (α‑SMA) and TGF‑β1 expression levels were determined via RT‑qPCR and western blotting. Data analysis was performed using R software. miR‑29c expression was significantly downregulated in the lungs of silicotic rats and in the pulmonary fibroblasts of the model of silicosis. Furthermore, COL1α1, COL3α1, α‑SMA and TGF‑β1 expression levels were significantly increased in cultured fibroblasts following 12 or 18 h exposure to SiO2. Lentiviral‑mediated knockdown of miR‑29c resulted in increased the expression levels of COL1α1, COL3α1, α‑SMA and TGF‑β1, while lentiviral‑mediated miR‑29c overexpression significantly suppressed the expression levels of these fibrosis‑related genes. Taken together, these results demonstrated that miR‑29c was significantly associated with silica‑induced pulmonary fibrosis and the expression levels of COL1α1, COL3α1, TGF‑β1 and α‑SMA are under the regulation of miR‑29c to different extents. This study therefore identified possible candidate molecular targets for preventing or delaying the occurrence and progression of silicosis. 10.3892/mmr.2021.11932
Single Intratracheal Quartz Instillation Induced Chronic Inflammation and Tumourigenesis in Rat Lungs. Scientific reports Crystalline silica (quartz) is known to induce silicosis and cancer in the lungs. In the present study, we investigated the relationship between quartz-induced chronic inflammation and lung carcinogenesis in rat lungs after a single exposure to quartz. F344 rats were treated with a single intratracheal instillation (i.t.) of quartz (4 mg/rat), and control rats were treated with a single i.t. of saline. After 52 or 96 weeks, the animals were sacrificed, and the lungs and other organs were used for analyses. Quartz particles were observed in the lungs of all quartz-treated rats. According to our scoring system, the lungs of rats treated with quartz had higher scores for infiltration of lymphocytes, macrophages and neutrophils, oedema, fibrosis, and granuloma than the lungs of control rats. After 96 weeks, the quartz-treated rats had higher incidences of adenoma (85.7%) and adenocarcinoma (81.0%) than control rats (20% and 20%, respectively). Quartz-treated and control rats did not show lung neoplastic lesions at 52 weeks after treatment. The number of lung neoplastic lesions per rat positively correlated with the degree of macrophage and lymphocyte infiltration, oedema, fibrosis, and lymph follicle formation around the bronchioles. In conclusion, single i.t. of quartz may induce lung cancer in rat along with chronic inflammation. 10.1038/s41598-020-63667-4
Macrophage autophagy protects mice from cerium oxide nanoparticle-induced lung fibrosis. Particle and fibre toxicology BACKGROUND:Cerium (Ce) is a rare earth element, rapidly oxidizing to form CeO, and currently used in numerous commercial applications, especially as nanoparticles (NP). The potential health effects of Ce remain uncertain, but literature indicates the development of rare earth pneumoconiosis accompanied with granuloma formation, interstitial fibrosis and inflammation. The exact underlying mechanisms are not yet completely understood, and we propose that autophagy could be an interesting target to study, particularly in macrophages. Therefore, the objective of our study was to investigate the role of macrophagic autophagy after pulmonary exposure to CeO NP in mice. Mice lacking the early autophagy gene Atg5 in their myeloid lineage and their wildtype counterparts were exposed to CeO NP by single oropharyngeal administration and sacrificed up to 1 month after. At that time, lung remodeling was thoroughly characterized (inflammatory cells infiltration, expression of fibrotic markers such as αSMA, TGFβ1, total and type I and III collagen deposition), as well as macrophage infiltration (quantification and M1/M2 phenotype). RESULTS:Such pulmonary exposure to CeO NP induces a progressive and dose-dependent lung fibrosis in the bronchiolar and alveolar walls, together with the activation of autophagy. Blockage of macrophagic autophagy protects from alveolar but not bronchiolar fibrosis, via the modulation of macrophage polarization towards M2 phenotype. CONCLUSION:In conclusion, our findings bring novel insight on the role of macrophagic autophagy in lung fibrogenesis, and add to the current awareness of pulmonary macrophages as important players in the disease. 10.1186/s12989-021-00398-y
Oxamate Attenuates Glycolysis and ER Stress in Silicotic Mice. International journal of molecular sciences Glycolysis and ER stress have been considered important drivers of pulmonary fibrosis. However, it is not clear whether glycolysis and ER stress are interconnected and if those interconnections regulate the development of pulmonary fibrosis. Our previous studies found that the expression of LDHA, a key enzyme involved in glycolysis, was increased in silica-induced macrophages and silicotic models, and it was closely related to silicosis fibrosis by participating in inflammatory response. However, whether pharmacological inhibition of LDHA is beneficial to the amelioration of silicosis fibrosis remains unclear. In this study, we investigated the effects of oxamate, a potent inhibitor of LDHA, on the regulation of glycolysis and ER stress in alveolar macrophages and silicotic mice. We found that silica induced the upregulation of glycolysis and the expression of key enzymes directly involved in ER stress in NR8383 macrophages. However, treatment of the macrophages and silicotic mice with oxamate attenuated glycolysis and ER stress by inhibiting LDHA, causing a decrease in the production of lactate. Therefore, oxamate demonstrated an anti-fibrotic role by reducing glycolysis and ER stress in silicotic mice. 10.3390/ijms23063013
Macrophage-derived MMP12 promotes fibrosis through sustained damage to endothelial cells. Journal of hazardous materials Macrophages are essential for the maintenance of endothelial cell function. However, the potential impact and mechanisms of crosstalk between macrophages and endothelial cells during silicosis progression remain unexplored. To fill this knowledge gap, a mouse model of silicosis was established. Single cell sequencing, spatial transcriptome sequencing, western blotting, immunofluorescence staining, tube-forming and wound healing assays were used to explore the effects of silicon dioxide on macrophage-endothelial interactions. To investigate the mechanism of macrophage-mediated fibrosis, MMP12 was specifically inactivated using siRNA and pharmacological approaches, and macrophages were depleted using disodium chlorophosphite liposomes. Compared to the normal saline group, the silica dust group showed altered macrophage-endothelial interactions. Matrix metalloproteinase family member MMP12 was identified as a key mediator of the altered function of macrophage-endothelial interactions after silica exposure, which was accompanied by pro-inflammatory macrophage activation and fibrotic progression. By using ablation strategies, macrophage-derived MMP12 was shown to mediate endothelial cell dysfunction by accumulating on the extracellular matrix. During the inflammatory phase of silicosis, MMP12 secreted by pro-inflammatory macrophages caused decreased endothelial cell viability, reduced migration, decreased trans-endothelial resistance and increased permeability; while during the fibrotic phase, macrophage-derived MMP12 sustained endothelial cell injury through accumulation on the extracellular matrix. 10.1016/j.jhazmat.2023.132733
Human umbilical cord mesenchymal stem cell-derived extracellular vesicles alleviated silica induced lung inflammation and fibrosis in mice via circPWWP2A/miR-223-3p/NLRP3 axis. Ecotoxicology and environmental safety Silicosis is a progressive inflammatory disease with poorly defined mechanisms and limited therapeutic options. Recent studies found that microRNAs (miRNAs) and circular RNAs (circRNAs) were involved in the development of respiratory diseases; however, the function of non-coding RNAs in silicosis was still needed to be further explored. We found that miR-223-3p was significantly decreased in macrophages and lung tissues of mice after silica treatment, which were consistent with the results of GEO database microarray analysis. Notably, NLRP3 is a target gene downstream of miR-223-3p. And circular RNA PWWP2A (circPWWP2A) was significantly elevated after silica stimulation. To elucidate the role of these RNAs in silica-induced inflammation in macrophages and lung tissues, we investigated the upstream molecular mechanisms of circPWWP2A on the inflammatory response. The inhibitory effect of miR-223-3p on its target NLRP3 was suppressed by circPWWP2A, which led to lung fibrosis. Our study found that circPWWP2A could adsorb miR-223-3p to regulate NLRP3 after silica stimulation in pulmonary fibrosis. And our results revealed that the circPWWP2A-miR-223-3p-NLRP3 axis was potentially instrumental in managing silica-induced inflammation and fibrosis. Previous studies have demonstrated that human umbilical cord mesenchymal stem cell-derived extracellular vesicles (hucMSC-EVs) exhibit anti-inflammatory and anti-fibrotic effects in multiple organs. However, the potential effectiveness of hucMSC-EVs against silicosis or the underlying mechanisms of their biological outcomes remains unclear. Therefore, we used 3D culture technology to extract hucMSC-EVs and observed their effects in macrophages and lung tissues, respectively. According to the EVmiRNA database, miR-223-3p was abundant in MSC-EVs. In addition, hucMSC-EVs may modulate lung function, reduce the secretion of inflammatory factors (NLRP3, IL-1β, IL-18 and cleaved Caspase-1) and attenuate the deposition of fibrosis-related factors (Collagen Ⅰ, Collagen Ⅲ, fibronectin and α-SMA). In vitro results evinced that hucMSC-EVs reduced the inflammatory response of macrophages and restricted the activation and proliferation of fibroblasts. Moreover, our study showed that hucMSCs-EVs acted as a mediator to transfer miR-223-3p to suppress circPWWP2A, thereby alleviating pulmonary fibrosis through the NLRP3 signaling pathway. These data may provide potentially novel strategies for investigating the pathogenesis of silicosis and developing novel treatments for this disease. 10.1016/j.ecoenv.2023.114537
[Research progress on immune pathogenesis of pneumoconiosis]. Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases Pneumoconiosis is a type of occupational disease with extensive influence and serious harm. It is a systemic disease of diffuse pulmonary fibrosis caused by the inhalation of industrial dust into the lungs, and pneumoconiosis can continue to progress without further dust exposure, eventually leading to respiratory failure and death. With the wide application of new materials, new technologies and new crafting, the increasing demand for industrial materials, the survival of a large number of dust-exposed workers during the industrial boom in the 20th century, the incidence and cumulative number of pneumoconiosis cases continued to remain high, which caused a vast economic burden to the society. The pathogenesis of pneumoconiosis is relatively complex and known to be related to mechanical stimulation, oxidative stress, inflammation, immune response, and genetic predisposition. The immune system, as the defense of the body, plays an important role in the development of pneumoconiosis. This paper reviews the recent progress on the immunological pathogenesis of pneumoconiosis. 10.3760/cma.j.cn121094-20210428-00235
Role of Nephronectin in Pathophysiology of Silicosis. Lee Suni,Honda Machiko,Yamamoto Shoko,Kumagai-Takei Naoko,Yoshitome Kei,Nishimura Yasumitsu,Sada Nagisa,Kon Shigeyuki,Otsuki Takemi International journal of molecular sciences Silicosis is a typical form of pneumoconiosis and is characterized as a type of lung fibrosis. Silica particles are captured and recognized upon by alveolar macrophages via the macrophage receptor with collagenous structure (MARCO) scavenger receptor, and thereafter the inflammasome is activated. Thereafter, various chemokines/cytokines play their roles to eventually form fibrosis. Additionally, silica particles chronically activate T helper cells which sets the background for the formation of silicosis-associated autoimmune disturbances. The occurrence and progression of lung fibrosis, the extracellular matrix-related molecules such as integrins and their ligands including fibronectin, vitronectin, laminin, and collagens, all play important roles. Here, the roles of these molecules in silicosis-related lung fibrosis are reviewed from the literature. Additionally, the measurement of serum nephronectin (Npnt), a new member of the integrin family of ligands, is discussed, together with investigations attempting to delineate the role of Npnt in silica-induced lung fibrosis. Serum Npnt was found to be higher in silicosis patients compared to healthy volunteers and seems to play a role in the progression of fibrosis with other cytokines. Therefore, serum Npnt levels may be employed as a suitable marker to monitor the progression of fibrosis in silicosis patients. 10.3390/ijms20102581
VX-765 attenuates silica-induced lung inflammatory injury and fibrosis by modulating alveolar macrophages pyroptosis in mice. Ecotoxicology and environmental safety Silicosis is a diffuse fibrotic lung disease in which excessive inflammatory responses are triggered by silica exposure. Pyroptosis, a pro-inflammatory mode of programmed cell death, is mediated by gasdermin and may play a pivotal role in the development of silicosis. The caspase-1 inhibitor, VX-765, was used in vivo and in vitro to investigate the effects of silica-induced early inflammatory injury and later lung fibrosis. Our findings show that VX-765 reduces inflammatory lung injury by inhibiting silica-induced pyroptosis of alveolar macrophages in a silicosis mouse model. VX-765 limits the infiltration of inflammatory M1 alveolar macrophages, decreasing expression of inflammatory cytokines, including IL-1β, TNF-α, IL-6, CCL2, and CCL3, and down-regulating endogenous DAMPs and inflammatory immune-related cell pattern recognition receptors TLR4 and NLRP3. Furthermore, VX-765 alleviates fibrosis by down-regulating α-smooth muscle actin (α-SMA), collagen, and fibronectin. In this study, we illustrate that Alveolar macrophages pyroptosis occur in the early stages of silicosis, and VX-765 can alleviate the development of silicosis by inhibiting the pyroptosis signaling pathway. These results may provide new insight into the prevention and treatment of early-stage silicosis. 10.1016/j.ecoenv.2022.114359
Dioscin Exerts Protective Effects Against Crystalline Silica-induced Pulmonary Fibrosis in Mice. Li Chao,Lu Yiping,Du Sitong,Li Siyi,Zhang Yiting,Liu Fangwei,Chen Ying,Weng Dong,Chen Jie Theranostics Inhalation of crystalline silica particles leads to pulmonary fibrosis, eventually resulting in respiratory failure and death. There are few effective drugs that can delay the progression of this disease; thus, patients with silicosis are usually only offered supportive care. Dioscin, a steroidal saponin, exhibits many biological activities and health benefits including its protective effects against hepatic fibrosis. However, the effect of dioscin on silicosis is unknown. METHODS:We employed experimental mouse mode of silicosis. Different doses of dioscin were gavaged to the animals 1 day after crystalline silica instillation to see the effect of dioscin on crystalline silica induced pulmonary fibrosis. Also, we used RAW264.7 and NIH-3T3 cell lines to explore dioscin effects on macrophages and fibroblasts. Dioscin was also oral treatment but 10 days after crystalline silica instillation to see its effect on established pulmonary fibrosis. RESULTS:Dioscin treatment reduced pro-inflammation and pro-fibrotic cytokine secretion by modulating innate and adaptive immune responses. It also reduced the recruitment of fibrocytes, protected epithelial cells from crystalline silica injury, inhibited transforming growth factor beta/Smad3 signaling and fibroblast activation. Together, these effects delayed the progression of crystalline silica-induced pulmonary fibrosis. The mechanism by which dioscin treatment alleviated CS-induced inflammation appeared to be via the reduction of macrophage, B lymphocyte, and T lymphocte infiltration into lung. Dioscin inhibits macrophages and fibroblasts from secreting pro-inflammatory cytokines and may also function as a modulator of T helper cells responses, concurrent with attenuated phosphorylation of the apoptosis signal-regulating kinase 1-p38/c-Jun N-terminal kinase pathway. Also, dioscin could block the phosphorylation of Smad3 in fibroblast. Oral treatment of dioscin could also effectively postpone the progression of established silicosis. CONCLUSION:Oral treatment dioscin delays crystalline silica-induced pulmonary fibrosis and exerts pulmonary protective effects in mice. Dioscin may be a novel and potent candidate for protection against crystalline silica-induced pulmonary fibrosis. 10.7150/thno.20270
Necroptosis in pulmonary macrophages promotes silica-induced inflammation and interstitial fibrosis in mice. Tao Huihui,Zhao Hui,Ge Deyong,Liao Jinjun,Shao Luocheng,Mo Aowei,Hu LeLin,Xu Keyi,Wu Jing,Mu Min,Li Bin,Tao Xinrong,Wang Jianhua Toxicology letters Silicosis is a disease characterized by extensive lung nodules and fibrosis caused by the prolonged inhalation of silica in occupational settings. However, the molecular mechanism of silicosis development is complex and not fully understood. Furthermore, the role of necroptosis, a death receptor-mediated and caspase-independent mode of inflammatory cell death, is not well understood in silicosis. Here, we demonstrate that the necroptotic signaling pathway of macrophages is significantly activated in the lungs of silicosis mouse models. Meanwhile, increased M1 macrophage infiltration and up-regulation of pro-inflammatory cytokines (TNF-α, IL-6) were observed in our silicosis model. Notably, the expression of the pro-fibrotic factor, TGF-β1, and fibrosis biomarkers α-SMA and collagen I were also unregulated; however, these phenomena were recovered by Nec-1, an inhibitor specific for RIP1 kinase-dependent necroptosis. We conclude that macrophage-mediated necroptosis promotes the progression of silicosis by enhancing lung inflammatory responses and fibrogenesis in a mouse model of silicosis. These findings provide new insights for drug discovery and clinical treatment of silicosis. 10.1016/j.toxlet.2021.11.015
Adenovirus-mediated Overexpression of FcγRIIB Attenuates Pulmonary Inflammation and Fibrosis. American journal of respiratory cell and molecular biology Progressive fibrosing interstitial lung diseases (PF-ILDs) result in high mortality and lack effective therapies. The pathogenesis of PF-ILDs involves macrophages driving inflammation and irreversible fibrosis. Fc-γ receptors (FcγRs) regulate macrophages and inflammation, but their roles in PF-ILDs remain unclear. We characterized the expression of FcγRs and found upregulated FcγRIIB in human and mouse lungs after exposure to silica. FcγRIIB deficiency aggravated lung dysfunction, inflammation, and fibrosis in silica-exposed mice. Using single-cell transcriptomics and experiments, FcγRIIB was found in alveolar macrophages, where it regulated the expression of fibrosis-related genes and . In mice with macrophage-specific overexpression of FcγRIIB and in mice treated with adenovirus by intratracheal instillation to upregulate FcγRIIB, silica-induced functional and histological changes were ameliorated. Our data from three genetic models and a therapeutic model suggest that FcγRIIB plays a protective role that can be enhanced by adenoviral overexpression, representing a potential therapeutic strategy for PF-ILDs. 10.1165/rcmb.2022-0056OC
Blocking Caspase-1/Gsdmd and Caspase-3/-8/Gsdme pyroptotic pathways rescues silicosis in mice. PLoS genetics Millions of patients suffer from silicosis, but it remains an uncurable disease due to its unclear pathogenic mechanisms. Though the Nlrp3 inflammasome is involved in silicosis pathogenesis, inhibition of its classic downstream factors, Caspase-1 and Gsdmd, fails to block pyroptosis and cytokine release. To clarify the molecular mechanism of silicosis pathogenesis for new therapy, we examined samples from silicosis patients and genetic mouse models. We discovered an alternative pyroptotic pathway which requires cleavage of Gsdme by Caspases-3/8 in addition to Caspase-1/Gsdmd. Consistently, Gsdmd-/-Gsdme-/- mice showed markedly attenuated silicosis pathology, and Gsdmd-/-Gsdme-/- macrophages were resistant to silica-induced pyroptosis. Furthermore, we found that in addition to Caspase 1, Caspase-8 cleaved IL-1β in silicosis, explaining why Caspase-1-/- mice also suffered from silicosis. Finally, we found that inhibitors of Caspase-1, -3, -8 or an FDA approved drug, dimethyl fumarate, could dramatically alleviate silicosis pathology through blocking cleavage of Gsdmd and Gsdme. This study highlights that Caspase-1/Gsdmd and Caspase-3/8/Gsdme-dependent pyroptosis is essential for the development of silicosis, implicating new potential targets and drug for silicosis treatment. 10.1371/journal.pgen.1010515
Coal dust exposure triggers heterogeneity of transcriptional profiles in mouse pneumoconiosis and Vitamin D remedies. Mu Min,Li Bing,Zou Yuanjie,Wang Wenyang,Cao Hangbing,Zhang Yajun,Sun Qixian,Chen Haoming,Ge Deyong,Tao Huihui,Hu Dong,Yuan Liang,Tao Xinrong,Wang Jianhua Particle and fibre toxicology BACKGROUND:Coal dust particles (CDP), an inevitable by-product of coal mining for the environment, mainly causes coal workers' pneumoconiosis (CWP). Long-term exposure to coal dust leads to a complex alternation of biological processes during regeneration and repair in the healing lung. However, the cellular and complete molecular changes associated with pulmonary homeostasis caused by respiratory coal dust particles remain unclear. METHODS:This study mainly investigated the pulmonary toxicity of respirable-sized CDP in mice using unbiased single-cell RNA sequencing. CDP (< 5 μm) collected from the coal mine was analyzed by Scanning Electron Microscope (SEM) and Mass Spectrometer. In addition, western blotting, Elisa, QPCR was used to detect gene expression at mRNA or protein levels. Pathological analysis including HE staining, Masson staining, immunohistochemistry, and immunofluorescence staining were performed to characterize the structure and functional alternation in the pneumoconiosis mouse and verify the reliability of single-cell sequencing results. RESULTS:SEM image and Mass Spectrometer analysis showed that coal dust particles generated during coal mine production have been crushed and screened with a diameter of less than 5 µm and contained less than 10% silica. Alveolar structure and pulmonary microenvironment were destroyed, inflammatory and death (apoptosis, autophagy, and necrosis) pathways were activated, leading to pneumoconiosis in post 9 months coal dust stimulation. A distinct abnormally increased alveolar type 2 epithelial cell (AT2) were classified with a highly active state but reduced the antimicrobial-related protein expression of LYZ and Chia1 after CDP exposure. Beclin1, LC3B, LAMP2, TGF-ß, and MLPH were up-regulated induced by CDP, promoting autophagy and pulmonary fibrosis. A new subset of macrophages with M2-type polarization double expressed MLPH + /CD206 + was found in mice having pneumoconiosis but markedly decreased after the Vitamin D treatment. Activated MLPH + /CD206 + M2 macrophages secreted TGF-β1 and are sensitive to Vitamin D treatment. CONCLUSIONS:This is the first study to reconstruct the pathologic progression and transcriptome pattern of coal pneumoconiosis in mice. Coal dust had obvious toxic effects on lung epithelial cells and macrophages and eventually induced pulmonary fibrosis. CDP-induced M2-type macrophages could be inhibited by VD, which may be related to the alleviation of the pulmonary fibrosis process. 10.1186/s12989-022-00449-y
Caveolin-1 negatively regulates inflammation and fibrosis in silicosis. He RongLing,Yuan XiangNing,Lv Xin,Liu QingXiang,Tao LiJian,Meng Jie Journal of cellular and molecular medicine Inhalation of crystalline silica causes silicosis, the most common and serious occupational disease, which is characterized by progressive lung inflammation and fibrosis. Recent studies revealed the anti-inflammatory and anti-fibrosis role of Caveolin-1 (Cav-1) in lung, but this role in silicosis has not been investigated. Thus, this study evaluated Cav-1 regulatory effects in silicosis. It was found that Cav-1 levels were significantly reduced in the lung from silicosis patients and silicotic mice. The silicosis models were established in C57BL/6 (wild-type) and Cav-1 deficiency (Cav-1 ) mice, and Cav-1 mice displayed wider alveolar septa, increased collagen deposition and more silicotic nodules. The mice peritoneal-derived macrophages were used to explore the role of Cav-1 in silica-induced inflammation, which plays a central role in mechanism of silicosis. Cav-1 inhibited silica-induced infiltration of inflammatory cells and secretion of inflammatory factors in vitro and in vivo, partly by downregulating NF-κB pathway. Additionally, silica uptake and expression of 4-hydroxynonenal in silicotic mice were observed, and it was found that Cav-1 absence triggered excessive silica deposition, causing a stronger oxidative stress response. These findings demonstrate the protective effects of Cav-1 in silica-induced lung injury, suggesting its potential therapeutic value in silicosis. 10.1111/jcmm.17045
Autophagy, an important therapeutic target for pulmonary fibrosis diseases. Zhao Hong,Wang Yiqun,Qiu Tingting,Liu Wei,Yao Pingbo Clinica chimica acta; international journal of clinical chemistry As an evolutionarily conserved intracellular degradation pathway, autophagy is essential to cellular homeostasis. Several studies have demonstrated that autophagy showed an important effect on some pulmonary fibrosis diseases, including idiopathic pulmonary fibrosis (IPF), cystic fibrosis lung disease, silicosis and smoking-induced pulmonary fibrosis. For example, autophagy mitigates the pathological progression of IPF by regulating the apoptosis of fibroblasts and the senescence of alveolar epithelial cells. In addition, autophagy ameliorates cystic fibrosis lung disease via rescuing transmembrane conductance regulators (CFTRs) to the plasma membrane. Furthermore, autophagy alleviates the silica-induced pulmonary fibrosis by decreasing apoptosis of alveolar epithelial cells in silicosis. However, excessive macrophage autophagy aggravates the pathogenesis of silicosis fibrosis by promoting the proliferation and migration of lung fibroblasts in silicosis. Autophagy is also involved in smoking-induced pulmonary fibrosis, coal workers' pneumoconiosis, ionizing radiation-mediated pulmonary fibrosis and heavy metal nanoparticle-mediated pulmonary fibrosis. In this review, the role and signalling mechanisms of autophagy in the progression of pulmonary fibrosis diseases have been systematically analysed. It has provided a new insight into the therapeutic potential associated with autophagy in pulmonary fibrosis diseases. In conclusion, the targeting of autophagy might prove to be a prospective avenue for the therapeutic intervention of pulmonary fibrosis diseases. 10.1016/j.cca.2019.12.016
Targeting Mechanics-Induced Fibroblast Activation through CD44-RhoA-YAP Pathway Ameliorates Crystalline Silica-Induced Silicosis. Li Siyi,Li Chao,Zhang Yiting,He Xiu,Chen Xi,Zeng Xinning,Liu Fangwei,Chen Ying,Chen Jie Theranostics Silicosis is pneumoconiosis of the lung, usually resulting from prolonged exposure to crystalline silica (CS). The hallmark of silicosis is excessive extracellular matrix (ECM) deposition produced by activated fibroblasts. Recent work demonstrated that excessive ECM-forming mechanical cues play an essential role in promoting fibroblast activation and perpetuating fibrotic pathologies. However, the detailed molecular mechanism still needs to be uncovered. : NIH-3T3 fibroblasts were cultured on either 1 kappa (soft) or 60 kappa (stiff) gel-coated coverslips. A series of knockdown and reverse experiments were performed to establish the signaling for mechanics-induced fibroblast activation. An experimental model of silicosis was established by one-time intratracheal instillation of CS suspension. The cluster of differentiation 44 (CD44) antibody (IM7), dihydrotanshinone I (DHI) and verteporfin (VP) were used to explore the effect of CD44-RhoA-YAP signaling blockade on mechanics-induced fibroblast activation and CS-induced pulmonary fibrosis. : Matrix stiffness could induce nuclear translocation of the Yes-associated protein (YAP) through CD44 in fibroblasts. This effect required RhoA activity and F-actin cytoskeleton polymerization but was independent of Hippo pathway kinases, Mst 1 and Lats 1, forming CD44-RhoA-YAP signaling pathway. Pharmacological upstream blocking by CD44 antibody or downstream blockade of YAP by DHI or VP could attenuate fibroblast migration, invasion, proliferation, and collagen deposition. Furthermore, CD44-RhoA-YAP signaling blockade could alleviate CS-induced fibrosis and improve pulmonary function . : CD44-RhoA-YAP signaling mediates mechanics-induced fibroblast activation. Targeting this pathway could ameliorate crystalline silica-induced silicosis and provide a potential therapeutic strategy to mitigate fibrosis. 10.7150/thno.35665
Pirfenidone ameliorates pulmonary inflammation and fibrosis in a rat silicosis model by inhibiting macrophage polarization and JAK2/STAT3 signaling pathways. Ecotoxicology and environmental safety Macrophages play an important role in causing silicosis eventually becoming an irreversible fibrotic disease, and there are no specific drugs for silicosis in the clinic so far. Pirfenidone has consistently been shown to have anti-inflammatory and anti-fibrotic effects, but the specific mechanism by which it ameliorates fibrosis in silicosis is unclear. A rat silicosis model was established in this study, and lung tissues and serum were collected by batch execution at 14, 28, and 56 days. Also, the effects of Pirfenidone on macrophage polarization and pulmonary fibrosis were evaluated in silicosis with early intervention and late treatment by histological examination, Enzyme-linked immunosorbent assay, Hydroxyproline assay, Western blot and Quantitative reverse transcription polymerase chain reaction. The results showed that Pirfenidone significantly reduced pulmonary fibrosis in rats with silicosis, and both early intervention and late treatment effectively inhibited the expression of α-SMA, Col-I, Vimentin, Hydroxyproline, IL-1β, IL-18, and the M2 macrophage marker CD206 and Arg-1, while only early intervention effectively inhibited E-cad, TGF-β1, TNF-α, and the M1 macrophage marker iNOS, CD86. Furthermore, Pirfenidone dramatically reduced the mRNA expression of the JAK2/STAT3. These findings imply that Pirfenidone may reduce pulmonary fibrosis in silicosis rats by inhibiting macrophage polarization via the JAK2/STAT3 signaling pathway. 10.1016/j.ecoenv.2022.114066
Silica-stimulated monocytes release fibroblast proliferation factors identical to interleukin 1. A potential role for interleukin 1 in the pathogenesis of silicosis. Schmidt J A,Oliver C N,Lepe-Zuniga J L,Green I,Gery I The Journal of clinical investigation Previous study strongly suggests that silicotic fibrosis is mediated by macrophages and their soluble mediators. The biochemical properties of the mediators involved in silicotic fibrosis, however, are as yet ill defined. The current study, therefore, determined whether human monocyte-macrophages treated with fibrogenic silica dust released factors capable of activating fibroblasts as measured by an increase in fibroblast proliferation. Silica, but not nonfibrogenic diamond dust, stimulated the release of fibroblast proliferation factors. Moreover, the level of fibroblast proliferation activity was comparable with the level of thymocyte proliferation (interleukin-1) activity in the same culture supernatants. The factors responsible for these seemingly diverse activities were found to behave identically when analyzed by gel filtration chromatography, size exclusion chromatography, isoelectrofocusing, ion exchange chromatography, and hydrophobic chromatography. Moreover, the response of these factors to four different proteases and heat (56 degrees C) was also identical, which shows that their comigration on various separation media could not be explained by noncovalent interaction between otherwise unrelated species. The data demonstrate that a monocyte-derived thymocyte proliferation factor having the molecular properties of interleukin 1 is capable of regulating fibroblast proliferation. In silicosis and other fibrotic diseases, the local release of interleukin 1 may contribute to abnormal connective tissue deposition by stimulating fibroblast proliferation, and thereby, amplifying other signals stimulating the synthesis of connective tissue components. 10.1172/JCI111350
Surface interactions with compartmentalized cellular phosphates explain rare earth oxide nanoparticle hazard and provide opportunities for safer design. Li Ruibin,Ji Zhaoxia,Chang Chong Hyun,Dunphy Darren R,Cai Xiaoming,Meng Huan,Zhang Haiyuan,Sun Bingbing,Wang Xiang,Dong Juyao,Lin Sijie,Wang Meiying,Liao Yu-Pei,Brinker C Jeffrey,Nel Andre,Xia Tian ACS nano Growing international exploitation of rare earth oxides (REOs) for commercial and biological use has increased the possibility of human exposure and adverse health effects. Occupational exposure to rare earth materials in miners and polishers leads to a severe form of pneumoconiosis, while gadolinium-containing MRI contrast agents cause nephrogenic systemic fibrosis in patients with renal impairment. The mechanisms for inducing these adverse pro-fibrogenic effects are of considerable importance for the safety assessment of REO particles as well as presenting opportunities for safer design. In this study, using a well-prepared REO library, we obtained a mechanistic understanding of how REOs induce cellular and pulmonary damage by a compartmentalized intracellular biotransformation process in lysosomes that results in pro-fibrogenic growth factor production and lung fibrosis. We demonstrate that rare earth oxide ion shedding in acidifying macrophage lysosomes leads to biotic phosphate complexation that results in organelle damage due to stripping of phosphates from the surrounding lipid bilayer. This results in nanoparticle biotransformation into urchin shaped structures and setting in motion a series of events that trigger NLRP3 inflammasome activation, IL-1β release, TGF-β1 and PDGF-AA production. However, pretreatment of REO nanoparticles with phosphate in a neutral pH environment prevents biological transformation and pro-fibrogenic effects. This can be used as a safer design principle for producing rare earth nanoparticles for biological use. 10.1021/nn406166n
Maintenance of alveolitis in patients with chronic beryllium disease by beryllium-specific helper T cells. Saltini C,Winestock K,Kirby M,Pinkston P,Crystal R G The New England journal of medicine Chronic beryllium disease is characterized by the accumulation of helper/inducer T cells, macrophages, and granulomas in the lungs. To evaluate the hypothesis that the proliferation of CD4+ (helper/inducer) T cells in the lungs of patients with this disorder is maintained by local activation of beryllium-specific T-cell clones, we studied T cells obtained from peripheral blood and by bronchoalveolar lavage in eight patients and five healthy controls. The proliferation of T cells in response to beryllium in vitro was confined to the CD4+ T cells from the patients and was dependent on the presentation of antigen in the presence of both major histocompatibility complex class II antigens and functional interleukin-2 receptors. T cells from the patients' lungs had a significantly greater response to beryllium than did T cells from their peripheral blood (stimulation index, 103 vs. 5; P less than 0.01). Lines and clones of cells developed from T cells from the patients' lungs showed dose-dependent proliferation in response to beryllium but did not respond to recall antigens or to other metals. Although all beryllium-specific T-cell clones were CD4+ and none were CD8+ (suppressor/cytotoxic), all beryllium-specific clones studied had different rearrangements of T-cell antigen receptors, suggesting that the response to beryllium involved T cells with diverse specificities for beryllium. We conclude that in patients with chronic beryllium disease, beryllium acts as a class II-restricted antigen, stimulating local proliferation and accumulation in the lung of beryllium-specific CD4+ (helper/inducer) T cells. Hence, chronic beryllium disease is a hypersensitivity disease in which beryllium is the specific antigen. 10.1056/NEJM198904273201702
Silica particles enhance peripheral thrombosis: key role of lung macrophage-neutrophil cross-talk. Nemmar Abderrahim,Nemery Benoit,Hoet Peter H M,Van Rooijen Nico,Hoylaerts Marc F American journal of respiratory and critical care medicine RATIONALE:Inflammation and thrombosis are related via interactions between leukocytes, platelets, the vasculature, and the coagulation system. However, the mechanisms behind these interactions remain poorly understood. OBJECTIVES:We have investigated the effects of the well known pulmonary inflammation induced by silica for the development of peripheral thrombogenicity in a hamster model of thrombosis. In addition, the consequences of pulmonary macrophage and circulating monocyte and neutrophil depletion on the thrombogenicity were investigated. METHODS:Silica particles (2-200 mug/hamster) were intratracheally instilled, and experimental thrombosis in photochemically induced femoral vein lesions was assessed 24 hours later, in association with cellular infiltration in the lung. MEASUREMENTS AND MAIN RESULTS:Intratracheally instilled silica particles (20 and 200 mug/hamster) triggered pulmonary inflammation, together with stimulation of peripheral platelet-rich thrombus formation. Both the selective depletion of lung macrophages by intratracheal administration of clodronate liposomes and the combined depletion of circulating monocytes and neutrophils by intraperitoneal injection of cyclophosphamide significantly reduced silica-induced influx of macrophages and neutrophils in bronchoalveolar lavage, and reduced peripheral thrombogenicity. Silica-induced lung inflammation was accompanied by increased neutrophil elastase levels in bronchoalveolar lavage and in plasma. Specific neutrophil elastase inhibition in the lung did not affect lung inflammation but reduced peripheral thrombogenicity. CONCLUSION:These findings uncover pulmonary macrophage-neutrophil cross-talk releasing neutrophil elastase into the blood circulation. Elastase, triggering activation of circulating platelets, may then predispose platelets to initiate thrombotic events on mildly damaged vasculature. 10.1164/rccm.200409-1202OC
Mesenchymal stem cells use extracellular vesicles to outsource mitophagy and shuttle microRNAs. Phinney Donald G,Di Giuseppe Michelangelo,Njah Joel,Sala Ernest,Shiva Sruti,St Croix Claudette M,Stolz Donna B,Watkins Simon C,Di Y Peter,Leikauf George D,Kolls Jay,Riches David W H,Deiuliis Giuseppe,Kaminski Naftali,Boregowda Siddaraju V,McKenna David H,Ortiz Luis A Nature communications Mesenchymal stem cells (MSCs) and macrophages are fundamental components of the stem cell niche and function coordinately to regulate haematopoietic stem cell self-renewal and mobilization. Recent studies indicate that mitophagy and healthy mitochondrial function are critical to the survival of stem cells, but how these processes are regulated in MSCs is unknown. Here we show that MSCs manage intracellular oxidative stress by targeting depolarized mitochondria to the plasma membrane via arrestin domain-containing protein 1-mediated microvesicles. The vesicles are then engulfed and re-utilized via a process involving fusion by macrophages, resulting in enhanced bioenergetics. Furthermore, we show that MSCs simultaneously shed micro RNA-containing exosomes that inhibit macrophage activation by suppressing Toll-like receptor signalling, thereby de-sensitizing macrophages to the ingested mitochondria. Collectively, these studies mechanistically link mitophagy and MSC survival with macrophage function, thereby providing a physiologically relevant context for the innate immunomodulatory activity of MSCs. 10.1038/ncomms9472
STING-dependent sensing of self-DNA drives silica-induced lung inflammation. Benmerzoug Sulayman,Rose Stéphanie,Bounab Badreddine,Gosset David,Duneau Laure,Chenuet Pauline,Mollet Lucile,Le Bert Marc,Lambers Christopher,Geleff Silvana,Roth Michael,Fauconnier Louis,Sedda Delphine,Carvalho Clarisse,Perche Olivier,Laurenceau David,Ryffel Bernhard,Apetoh Lionel,Kiziltunc Ahmet,Uslu Hakan,Albez Fadime Sultan,Akgun Metin,Togbe Dieudonnée,Quesniaux Valerie F J Nature communications Silica particles induce lung inflammation and fibrosis. Here we show that stimulator of interferon genes (STING) is essential for silica-induced lung inflammation. In mice, silica induces lung cell death and self-dsDNA release in the bronchoalveolar space that activates STING pathway. Degradation of extracellular self-dsDNA by DNase I inhibits silica-induced STING activation and the downstream type I IFN response. Patients with silicosis have increased circulating dsDNA and CXCL10 in sputum, and patients with fibrotic interstitial lung disease display STING activation and CXCL10 in the lung. In vitro, while mitochondrial dsDNA is sensed by cGAS-STING in dendritic cells, in macrophages extracellular dsDNA activates STING independent of cGAS after silica exposure. These results reveal an essential function of STING-mediated self-dsDNA sensing after silica exposure, and identify DNase I as a potential therapy for silica-induced lung inflammation. 10.1038/s41467-018-07425-1
Regulation of lung fibroblast proliferation and collagen synthesis by alveolar macrophages in experimental silicosis. I: Effect of macrophage conditioned medium from silica instilled rats. Benson S C,Belton J C,Scheve L G Journal of environmental pathology, toxicology and oncology : official organ of the International Society for Environmental Toxicology and Cancer Alveolar macrophages were lavaged from silica or saline instilled rats 0, 3, 7 and 14 days after exposure. Macrophages were cultured for twenty-four hours and the conditioned media assayed for the ability to stimulate rat lung fibroblast proliferation and collagen synthesis. Macrophages remained viable throughout the culture period. DNA synthesis was significantly elevated by macrophage conditioned media (MCM) from silica instilled rats (S-MCM) compared to untreated fibroblasts or fibroblasts exposed to MCM from saline instilled control animals (C-MCM). Stimulation of DNA synthesis was not observed when S-MCM was exposed to non-proliferating fibroblasts. Collagen synthesis quantitated as 3H-hydroxyproline accumulation or percent collagen synthesis was also increased by day 3 and day 7 S-MCM. Specific activity measurements of intracellular 3H-proline minimized the possibility that the increase in 3H-proline incorporation into collagen was a reflection of increased proline transport. Non-collagen protein synthesis was also increased in fibroblasts exposed to day 14 S-MCM. These results suggest that alveolar macrophages elaborate factors following silica exposure capable of altering the DNA and protein synthetic activity of lung fibroblasts. These changes in fibroblast DNA and protein metabolism are similar to those observed for lung tissue in vivo and lend further support to the hypothesis of macrophage mediation of the pulmonary response following silica exposure.
[Regulation role of superoxide dismutase coenzyme on Fas/FasL signal transduction and apoptosis in alveolar macrophages of pneumoconiosis patients]. Yao San-Qiao,Zhang Xi-Ying,Chen Zhi-Yuan Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases OBJECTIVE:To explore the role of superoxide dismutase (SOD) coenzyme in regulation of Fas/FasL signal transduction and apoptosis of alveolar macrophages in pneumoconiosis patients. METHODS:50 male and Han nationality cases, including the dust exposed workers, Phase I, II pneumoconiosis patients confirmed by local pneumoconiosis diagnosis group according to GBZ 70 - 2002 diagnosis standard, who underwent whole lung lavage treatment were chosen as subjects. Their alveolar macrophages (AMs) were collected and purified. The cells were divided into three groups: the untreated group, the Fas/FasL group and the SOD group. 5 x 10(6) purified AMs were added into incubating bottles containing DMEM for 2 hours for purifying, added with SOD coenzyme and other block reagents separately, and then incubated for 24 hours in CO(2) incubation. The cells were harvested and lysed. Western-blot were used to analyze the expressions of Fas, FasL, Caspases-8 and Caspases-3. Software of Quantity One 7.0 was used to analyze the relative quantity of Fas, FasL, Caspase-8 and Caspase-3. TUNEL and DNA fragment analysis were used to analyze AMs apoptosis. RESULTS:The apoptosis index in SOD coenzyme group (9.50 +/- 2.76)% and Fas/FasL group (14.01 +/- 2.56)% was significantly lower than that of in untreated group (19.18 +/- 2.83)% (P < 0.05). The catachrestic DNA ladder appeared in untreated group, was looming in Fas/FasL group, and was not found in the SOD group. The expressions of Fas, FasL, Caspase-8 and Caspase-3 of phase I and II in SOD group were higher than in the other two groups (P < 0.05). There was no significant difference in the expression of Fas, FasL, Caspase-8 and Caspase-3 among different phases of pneumoconiosis (P > 0.05). CONCLUSION:SOD coenzyme can effectively regulate Fas/FasL signal transduction and block AMs apoptosis.
Nitric oxide and reactive oxygen species production causes progressive damage in rats after cessation of silica inhalation. Porter Dale W,Millecchia Lyndell L,Willard Patsy,Robinson Victor A,Ramsey Dawn,McLaurin Jeffery,Khan Amir,Brumbaugh Kurt,Beighley Christoper M,Teass Alexander,Castranova Vincent Toxicological sciences : an official journal of the Society of Toxicology Our laboratory has previously reported results from a rat silica inhalation study which determined that, even after silica exposure ended, pulmonary inflammation and damage progressed with subsequent fibrosis development. In the present study, the relationship between silica exposure, nitric oxide (NO) and reactive oxygen species (ROS) production, and the resultant pulmonary damage is investigated in this model. Rats were exposed to silica (15 mg/m3, 6 h/day) for either 20, 40, or 60 days. A portion of the rats from each exposure were sacrificed at 0 days postexposure, while another portion was maintained without further exposure for 36 days to examine recovery or progression. The major findings of this study are: (1) silica-exposed rat lungs were in a state of oxidative stress, the severity of which increased during the postexposure period, (2) silica-exposed rats had significant increase in lung NO production which increased in magnitude during the postexposure period, and (3) the presence of silica particle(s) in an alveolar macrophage (AM) was highly associated with inducible nitric oxide synthase (iNOS) protein. These data indicate that, even after silica exposure has ended, and despite declining silica lung burden, silica-induced pulmonary NO and ROS production increases, thus producing a more severe oxidative stress. A quantitative association between silica and expression of iNOS protein in AMs was also determined, which adds to our previous observation that iNOS and NO-mediated damage are associated anatomically with silica-induced pathological lesions. Future studies will be needed to determine whether the progressive oxidative stress, and iNOS activation and NO production, is a direct result of silica lung burden or a consequence of silica-induced biochemical mediators. 10.1093/toxsci/kfj075
[Differential expression of PRDX4 in alveolar macrophages of patients with silicosis]. Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases To identify the differential expression of Peroxiredoxin 4 (PRDX4) in alveolar macrophages (AMs) from patients with silicosis in different phases using Western blot. From June 2017 to June 2018, Twelve pneumoconiosis patients in the pneumoconiosis Department of Beidaihe Sanitarium were selected by random sampling. A msong them, there were 4 groups, that was lung with dust, silicosis with grade one, silicosis with grade two, silicosis with grade three. There were 3 persons in each group, a total of 12. AMs was obtained by filtration and centrifugation. The intracellular protein was extracted and PRDX4 was detected by using Western blot method. It results showed that PRDX4 was expressed in AMs in 4 groups; with the increase of fibrosis, the average relative expression of PRDX4 in AMs was 0.258±0.026, 0.214±0.012, 0.180±0.004, 0.165±0.008. The highest expression level was in the lung with dust group, and the lowest was in the silicosis with grade three group. The difference of the expression level of PRDX4 protein in AMs between groups was statistically significant (<0.05) . This experiment verified that PRDX4 expressed differentially in AMs in patients with silicosis. With the development of silicosis, PRDX4 expression in AMs reduced significantly. 10.3760/cma.j.cn121094-20190417-00155
Trehalose alleviates apoptosis by protecting the autophagy-lysosomal system in alveolar macrophages during human silicosis. Life sciences BACKGROUND:Alveolar macrophages (AMs) are the primary targets of silicosis. Blockade of autophagy may aggravate the apoptosis of AMs. Trehalose (Tre), a transcription factor EB (TFEB) activator, may impact the autophagy-lysosomal system in AMs during silicosis. However, the mechanism by which Tre acts upon AMs in silicosis is unknown. METHODS:We collected AMs from twenty male workers exposed to silica and divided them into observer and silicosis patient groups. AMs from the two groups were then exposed to Tre. Western blot was used to measure the expression of autophagy-associated proteins. Lysosomal-associated membrane protein 1 (LAMP1) expression was observed using immunofluorescence and western blot. Apoptosis of the AMs was detected by TUNEL assay and western blot. RESULTS:Tre induced localization of TFEB to the nucleus in the AMs of both groups. After Tre exposure, LAMP1 levels increased and LC3 levels decreased in the AMs of both groups, suggesting that Tre may increase the function of the autophagy-lysosomal system. The LC3-II/I ratio in the Tre-exposed AMs was lower than in the AMs not exposed to Tre. The LC3-II/I ratio in AMs subjected to Tre plus Bafilomycin (Baf) was higher than the ratio in cells exposed to Tre or Baf individually. Additionally, p62 levels decreased after Tre stimulation in the AMs of both groups. This indicates that Tre may accelerate the process of autophagic degradation. We also found decreased levels of cleaved caspase-3 after Tre treatment in the AMs of both groups. However, p-mTOR (Ser2448) and p-mTOR (Ser2481) levels did not change significantly after Tre treatment, suggesting that the mTOR signaling pathway was not affected by Tre treatment. CONCLUSION:Our findings suggest that the restoration of autophagy-lysosomal function by Tre may be a potential protective strategy against silicosis. 10.1016/j.lfs.2020.118043
Dynamic changes of mononuclear phagocytes in circulating, pulmonary alveolar and interstitial compartments in a mouse model of experimental silicosis. Xiang Guo-An,Zhang Yi-Dan,Su Cheng-Cheng,Ma Yong-Qiang,Li Yu-Ming,Zhou Xin,Wei Lu-Qing,Ji Wen-Jie Inhalation toxicology CONTEXT:Silicosis is a devastating, irreversible lung fibrosis condition exposed to crystalline silica. The mononuclear phagocyte system plays an important role in the pathogenesis of silicosis. OBJECTIVE:The present study was aimed to explore the dynamic changes of mononuclear phagocytes in circulating, pulmonary alveolar and interstitial compartments in experimental silicosis model. MATERIALS AND METHODS:A mouse model of lung fibrosis was developed with crystalline silica particles (2 mg/40 μL via oropharyngeal instillation) using male C57BL/6 mice, and were killed on days 1, 3, 7, 14, and 28. The lung inflammation and fibrosis was investigated using hematoxylin-eosin staining and bronchoalveolar lavage fluid (BALF) analysis, Masson's trichrome staining, and immunofluorescence. Circulating monocyte subsets (Ly6C(hi) and Ly6C(lo)), polarization state of BALF-derived alveolar macrophages (AMϕ) and lung interstitial macrophages (IMϕ, derived from enzymatically digested lung tissue) were analyzed by flow cytometry. RESULTS:The percentage of Ly6C(hi) monocytes significantly increased on day 1 after silica exposure, which reached the peak level from day 7 till day 28. Moreover, M2 (alternative activation) AMϕ (PI - CD64 + CD206+) was dramatically and progressively increased from day 1 to day 28. A parallel increase in IMϕ with M2 polarization (PI-CD64 + CD11b + CD206+) was also observed from day 1 to day 28. CONCLUSION:Our data demonstrate a dynamic view of mononuclear phagocyte change in three compartments after silica challenge, which highlights the remodeling of mononuclear phagocyte system as a potential therapeutic target for silicosis. 10.1080/08958378.2016.1188186
4-1BB Signaling Promotes Alveolar Macrophages-Mediated Pro-Fibrotic Responses and Crystalline Silica-Induced Pulmonary Fibrosis in Mice. Lu Yiping,Li Chao,Du Sitong,Chen Xi,Zeng Xinning,Liu Fangwei,Chen Ying,Chen Jie Frontiers in immunology Silicosis is caused by exposure to crystalline silica (CS). We have previously shown that blocking 4-1BB signaling attenuated CS-induced inflammation and pulmonary fibrosis. However, the cells that express 4-1BB, which plays a vital role in promoting fibrosis, are still unknown. In this study, we demonstrated that the expression of 4-1BB is elevated in alveolar macrophages (AMs) in the lungs of CS-injured mice. CS exposure also markedly enhanced the expression of 4-1BB in macrophage-like, MH-S cells. In these cells, activation of the 4-1BB signaling with an agonist antibody led to upregulated secretion of pro-fibrotic mediators. Consistently, blocking 4-1BB downstream signaling or genetic deletion of 4-1BB alleviated pro-fibrotic responses , while treatment with a 4-1BB fusion protein promoted pro-fibrotic responses. experiments showed that blocking 4-1BB signaling decreased the expressions of pro-fibrotic mediators and fibrosis. These data suggest that 4-1BB signaling plays an important role in promoting AMs-mediated pro-fibrotic responses and pulmonary fibrosis. Our findings may provide a potential molecular target to reduce CS-induced fibrotic responses in occupational lung disease. 10.3389/fimmu.2018.01848
Superoxide anion release from blood monocytes and alveolar macrophages in patients with diffuse lung fibrosis. Sherson D,Nielsen H,Frederiksen J,Milman N,Struve-Christensen E,Petersen B N APMIS : acta pathologica, microbiologica, et immunologica Scandinavica Superoxide anion release (O2-) after stimulation with phorbol myristate acetate was measured in alveolar macrophages (AM) obtained by bronchoalveolar lavage and in blood monocytes from 47 patients with diffuse interstitial lung disease: idiopathic pulmonary fibrosis (N = 15), hypersensitivity pneumonitis (N = 7), pneumoconiosis (N = 6) and sarcoidosis (N = 19). Differential cell counts demonstrated a lymphocyte predominance in patients with hypersensitivity pneumonitis (HP) and sarcoidosis while the other groups had neutrophil predominance. No correlation between O2- activity in alveolar macrophages (AM) or blood monocytes (BM) compared to lung function (VC and diffusing capacity) could be demonstrated. Smoking pneumoconiotics had significantly decreased BM O2- release (1.25 +/- 0.25 (SEM) nmol/min/10(6) cells) and significantly increased AM/BM O2- ratios (2.04 +/- 0.26) compared to smokers with idiopathic pulmonary fibrosis (IPF) who had the following mean values: BM O2- release = 2.58 +/- 0.25 and AM/BM O2- ratio = 0.86 +/- 0.23. When matched for sex and smoking, a significantly increased AM/BM O2- ratio was seen among patients with HP (2.19 +/- 0.98) in comparison with patients who had sarcoidosis (0.40 +/- 0.18). Patients with either HP or pneumoconiosis had generally elevated AM O2- release and reduced BM O2- release. These results suggest that environmentally related interstitial lung disorders (HP and pneumoconiosis) may be associated with elevated AM O2- release relative to BM O2- release in comparison to non-environmentally related disorders (IPF or sarcoidosis).
The effects of asbestos inhalation on the distribution and enhancement of immunoassociated antigen expression of alveolar macrophage subpopulation. Inamoto T,Georgian M M,Kagan E,Ogimoto K The Journal of veterinary medical science We have studied the effects of in vivo asbestos exposure on the surface immune-associated (Ia) antigen expression and distribution of alveolar macrophage subpopulations defined by continuous iso-osmotic Percoll gradients (density range: 1.006 to 1.123 g/ml) using a rat model of asbestos inhalation. Two groups of rats were exposed by intermittent inhalation (6 hr/day for 5 days/week over 4 weeks) to either amphibole (crocidolite) or serpentine (chrysotile) asbestos. A group of control rats was sham-exposed to clean air only. Alveolar macrophages from rats of three groups were obtained by bronchoalveolar lavage. During exposure, distinct differences appeared within 7 days of asbestos exposure, and some of these findings persisted in the crocidolite-exposed group for as long as 2 to 5 months after the cessation of exposure. Furthermore, relatively greater proportions of Ia-antigen positive cells were detected in several density fractions obtained from both asbestos-exposed groups (especially the crocidolite-exposed group). Multinucleated alveolar macrophages were seen frequently in all Percoll fractions after both types of asbestos inhalation. A significant proportion of multinucleated alveolar macrophages in these fractions expressed surface Ia-antigen positivity. The finding of enriched numbers of higher-density phagocytes in bronchoalveolar lavage cell subpopulations from asbestos-exposed rats may reflect the presence of newly recruited-immature monocytes and/or macrophages at sites of intrapulmonary asbestos deposition. Also, increased proportions of Ia-antigen positive cells suggest that a part of them were functionally activated. 10.1292/jvms.54.829
Decreased sialidase activity in alveolar macrophages of guinea pigs exposed to coal mine dust. Terzidis-Trabelsi H,Lefèvre J P,Bignon J,Lambré C R Environmental health perspectives The origin of immune dysfunctions that are observed in pneumoconiotic miners still remains unknown. There is evidence that the carbohydrate moiety of membrane glycoconjugates is of primary importance in many functions of immunocompetent cells. The glycosylation, and especially the sialylation level of membrane components of various lymphocyte and macrophage subsets, vary depending on the state of cellular differentiation and activation. Sialidases, which may regulate the amount of sialic acids exposed on the cell membrane, can thus be considered as immunoregulatory enzymes. In this report, the sialidase activity has been measured in alveolar macrophages (AM) and in cell-free bronchoalveolar lavage fluid (BALF) from guinea pigs exposed for 4 months to coal mine dust at a concentration of 300 mg/m3. The samples were collected by bronchoalveolar lavage 2 months after cessation of exposure. The sialidase activity in the cell-free fluid and in the purified alveolar macrophages showed a 10-fold decrease (p less than 0.001). Kinetic parameters of the enzyme such as Km and optimum pH did not change. This changed activity was specific for sialidase, as two other lysosomal glycosidases, beta-galactosidase and N-acetylglucosaminidase, showed unchanged activities. These results suggest the possibility that, by inducing a decreased sialidase activity, exposure to coal mine dust may lead to a modified expression of AM membrane-associated sialic acids giving rise to altered immune functions (i. e., phagocytosis, antigen processing, response to cytokines, etc.). 10.1289/ehp.9297103
Protein expression in silica dust-induced transdifferentiated rats lung fibroblasts. Hao Chang Fu,Li Xiao Fang,Yao Wu Biomedical and environmental sciences : BES OBJECTIVE:To analyze the expression of different proteins in free silica-induced transdifferentiated rat lung fibroblasts. METHODS:Rat lung fibroblasts and alveolar macrophages were cultured. A transdifferentiation model of rat lung fibroblasts was established. Free silica was used as a stimulator for rat lung fibroblasts. Changes in α-SMA were detected by immunohistochemistry and Western blot, respectively. Protein of lung fibroblasts was extracted and analyzed by two-dimensional electrophoresis (2-DE). RESULTS:Six protein spots were identified by mass spectrometry, including glyceraldehyde 3-phosphate-dehydrogenase, peroxiredoxin 5, heterogeneous nuclear ribonucleoprotein A2, transgelin 2, keratin K6 and vimentin. CONCLUSION:Some proteins are changed in free silica-induced transdifferentiated rat lung fibroblasts. 10.3967/0895-3988.2013.09.006
Pulmonary inflammation and fibrosis in a murine model of asbestosis and silicosis. Possible role of tumor necrosis factor. Bissonnette E,Rola-Pleszczynski M Inflammation Prolonged asbestos and silica inhalation is associated with pulmonary inflammation and fibrosis. Several studies suggest that TNF may play a role in the development of inflammation and fibrosis. We studied TNF production in a murine model of asbestosis and silicosis. Asbestos fibers caused a significant inflammatory response at two weeks and pulmonary fibrosis beginning at one month. Pulmonary inflammation was principally caused by an accumulation of neutrophils (0.88 x 10(5) neutrophils/compared to 0.05 x 10(5) in controls). TNF production by bronchoalveolar cells was higher in asbestos-instilled mice at two weeks, but was significantly diminished in older mice. Pulmonary inflammation was observed until six months in silica-instilled mice. Neutrophils were also the principal protagonists of the inflammation. In this group, severe fibrosis was observed at two weeks. TNF production in silica-instilled mice was similar to controls, possibly due to the presence of large numbers of neutrophils (3.3 x 10(5)/lavage) that could adsorb TNF. In vitro experiments showed an augmentation of TNF production by bronchoalveolar cells in the presence of silica. Taken together, our data suggest that asbestos and silica stimulate alveolar macrophages to produce TNF, which can be involved in pulmonary inflammation and fibrosis.
Role of the alveolar macrophage in lung injury: studies with ultrafine particles. Oberdörster G,Ferin J,Gelein R,Soderholm S C,Finkelstein J Environmental health perspectives We conducted a series of experiments with ultrafine particles (approximately 20 nm) and larger particles (less than 200 nm) of "nuisance" dusts to evaluate the involvement of alveolar macrophages (AM) in particle-induced lung injury and particle translocation in rats. After intratracheal instillation of both ultrafine particles and larger particles of TiO2, we found a highly increased interstitial access of the ultrafine particles combined with a large acute inflammatory reaction as determined by lung lavage parameters. An additional experiment revealed that intratracheal instillation of phagocytized ultrafine TiO2 particles (inside AM) prevented both the pulmonary inflammatory reaction and the interstitial access of the ultrafine particles. Another experiment showed that the influx of polymorphonuclear cells (PMN) into the alveolar space unexpectedly decreased with higher doses of ultrafine particles, whereas alveolar epithelial permeability (protein leakage) increased. The divergence between PMN influx into the alveolar space and changes in alveolar epithelial permeability implies that they are separate events. Pulmonary inflammatory parameters determined by lung lavage analysis correlated best with the surface area of the retained particles rather than with their mass, volume, or numbers. Because higher doses resulted in an increased interstitialized fraction of particles, we suggest that inflammatory events induced by particles in the interstitial space can modify the inflammation in the alveolar space detectable by lung lavage. Our results demonstrate the dual role of AM for modifying particle-induced lung injury, i.e., both preventing such injury and contributing to it. We conclude that the increased pulmonary toxicity of ultrafine particles is related to their larger surface area and to their increased interstitial access.(ABSTRACT TRUNCATED AT 250 WORDS) 10.1289/ehp.97-1519541
[The role of pulmonary macrophages in the development of pulmonary fibrosis caused by asbestos]. Lewczuk E,Owczarek H,Stanislawska G Medycyna pracy The role of alveolar and interstitial macrophages in asbestos-induced pulmonary fibrosis is discussed. Asbestosis is thought to result from a series of cellular interaction involving the pulmonary macrophages and lung fibroblasts. Inhaled asbestos fibres activate serum complement-dependent chemoattractant for macrophages which accumulate at alveolar duct bifurcations playing a central role in phagocytosis fibers and forming early pulmonary lesions. After phagocytic stimulation macrophages release various chemotactic factors for neutrophils and other inflammatory cells including TNF, neutrophil chemotactic factor and many proinflammatory mediators such as prostaglandins, leukotrienes, thromboxane. Apart from that, macrophages produce free radical oxygen and release lysosome enzymes which may cause lung tissue injury. There is also concomitant accumulation of fibroblasts proliferating in response to macrophages-derived growth factors, interleukin-1 and fibronectin. As a result of those processes collagen production increase and pulmonary fibrosis develops.
Interferon-gamma production by specific lung lymphocyte phenotypes in silicosis in mice. Davis G S,Pfeiffer L M,Hemenway D R American journal of respiratory cell and molecular biology We recently described overproduction of interferon (IFN)-gamma by lung lymphocytes in mice with silicosis (11% of cells in air-control versus 19% of cells from silica-exposed mice; Davis and colleagues, Am. J. Respir. Cell Mol. Biol. 1999;20:813-824). We hypothesized that the increased IFN-gamma production might be due to selective enrichment of one lymphocyte phenotype. To test this hypothesis, small mononuclear cells from lung digest preparations of mice exposed 4 mo previously to cristobalite silica (70 mg/m(3), 12 d, 5 h/d) or to sham-air were stained for intracellular cytokines and surface antigen phenotypes, and examined by flow cytometry. Air-sham mouse lung digests included CD4(+) (16%) and CD8(+) (6%) T cells, gammadelta T-cell antigen receptor (TCR)(+) CD4(-)CD8(-) T cells (3%), natural killer (NK) cells (15%), B cells (6%), and macrophages (12%). The total number of lung lymphocytes was increased 1.7-fold in silicosis, but the phenotype frequencies did not change significantly. In the control lungs IFN-gamma was produced by three major phenotypes of lymphocytes: 5% of CD4(+) T cells, 5% of gammadelta-TCR(+) CD4(-)CD8(-) T cells, and 2% of NK cells. The percentage of each type producing IFN-gamma was increased 2- to 3-fold in silicosis. When multiplied by cell number, the increased percentages yielded a 3- to 5-fold increase in the total number of each IFN- gamma-producing phenotype in the lung. Our results demonstrate no selective phenotype enrichment but upregulated IFN-gamma production by at least three lymphocyte phenotypes. IFN-gamma may be an important signal driving lymphocyte differentiation and macrophage activation in silicosis. 10.1165/ajrcmb.22.4.3599
Pulmonary inflammation and crystalline silica in respirable coal mine dust: dose-response. Kuempel E D,Attfield M D,Vallyathan V,Lapp N L,Hale J M,Smith R J,Castranova V Journal of biosciences This study describes the quantitative relationships between early pulmonary responses and the estimated lung-burden or cumulative exposure of respirable-quartz or coal mine dust. Data from a previous bronchoalveolar lavage (BAL) study in coal miners (n = 20) and nonminers (n = 16) were used including cell counts of alveolar macrophages (AMs) and polymorphonuclear leukocytes (PMNs), and the antioxidant superoxide dismutase (SOD) levels. Miners' individual working lifetime particulate exposures were estimated from work histories and mine air sampling data, and quartz lung-burdens were estimated using a lung dosimetry model. Results show that quartz, as either cumulative exposure or estimated lung-burden, was a highly statistically significant predictor of PMN response (P < 0.0001); however cumulative coal dust exposure did not significantly add to the prediction of PMNs (P = 0.2) above that predicted by cumulative quartz exposure (P < 0.0001). Despite the small study size, radiographic category was also significantly related to increasing levels of both PMNs and quartz lung burden (P-values < 0.04). SOD in BAL fluid rose linearly with quartz lung burden (P < 0.01), but AM count in BAL fluid did not (P > 0.4). This study demonstrates dose-response relationships between respirable crystalline silica in coal mine dust and pulmonary inflammation, antioxidant production, and radiographic small opacities. 10.1007/bf02970133
iTRAQ-based secretome reveals that SiO induces the polarization of RAW264.7 macrophages by activation of the NOD-RIP2-NF-κB signaling pathway. Fu Rong,Li Qian,Fan Rong,Zhou Qinye,Jin Xiaohan,Cao Jin,Wang Jiabao,Ma Yongqiang,Yi Tailong,Zhou Maobin,Yao Sanqiao,Gao Hongsheng,Xu Zhongwei,Yang Zhen Environmental toxicology and pharmacology Silicosis is characterized by inflammation and pulmonary fibrosis due to long-term inhalation of crystalline silica (SiO). To clarify the role of macrophage polarization in the inflammatory response of silicosis, we used iTRAQ-coupled 2D LC-MS/MS to study the change in the secretome in RAW264.7 macrophages. We successfully screened 330 differentially expressed proteins, including 120 proteins with upregulated expression and 210 proteins with down-regulated expression (p < 0.05). Bioinformatics analysis showed that the differentially expressed proteins were mainly involved in biological processes, such as oxidative stress, mitochondrial damage, apoptosis and acute inflammatory response. In particular, the expression levels of mitochondrial apoptosis-related proteins, such as AKT1, BAX, HSPD1, TNF, CASP8 and DAP, were increased after SiO exposure. Taken together, our study indicated that SiO could induce macrophage polarization by activation of the NOD-RIP2-NF-κB signaling pathway in RAW264.7 macrophages. This may represent a potential mechanism in the development of silicosis. 10.1016/j.etap.2018.08.010
Asbestos-induced disruption of calcium homeostasis induces endoplasmic reticulum stress in macrophages. The Journal of biological chemistry Although the mechanisms for fibrosis development remain largely unknown, recent evidence indicates that endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR) may act as an important fibrotic stimulus in diseased lungs. ER stress is observed in lungs of patients with idiopathic pulmonary fibrosis. In this study we evaluated if ER stress and the UPR was present in macrophages exposed to chrysotile asbestos and if ER stress in macrophages was associated with asbestos-induced pulmonary fibrosis. Macrophages exposed to chrysotile had elevated transcript levels of several ER stress genes. Macrophages loaded with the Ca(2+)-sensitive dye Fura2-AM showed that cytosolic Ca(2+) increased significantly within minutes after chrysotile exposure and remained elevated for a prolonged time. Chrysotile-induced increases in cytosolic Ca(2+) were partially inhibited by either anisomycin, an inhibitor of passive Ca(2+) leak from the ER, or 1,2-bis(2-aminophenoxyl)ethane-N,N,N',N'-tetraacetic acid (BAPTA-AM), an intracellular Ca(2+) chelator known to deplete ER Ca(2+) stores. Anisomycin inhibited X-box-binding protein 1 (XBP1) mRNA splicing and reduced immunoglobulin-binding protein (BiP) levels, whereas BAPTA-AM increased XBP1 splicing and BiP expression, suggesting that ER calcium depletion may be one factor contributing to ER stress in cells exposed to chrysotile. To evaluate ER stress in vivo, asbestos-exposed mice showed fibrosis development, and alveolar macrophages from fibrotic mice showed increased expression of BiP. Bronchoalveolar macrophages from asbestosis patients showed increased expression of several ER stress genes compared with normal subjects. These findings suggest that alveolar macrophages undergo ER stress, which is associated with fibrosis development. 10.1074/jbc.M114.579870
Type I interferon signaling contributes to chronic inflammation in a murine model of silicosis. Giordano Giulia,van den Brûle Sybille,Lo Re Sandra,Triqueneaux Perrine,Uwambayinema Francine,Yakoub Yousof,Couillin Isabelle,Ryffel Bernhard,Michiels Thomas,Renauld Jean-Christophe,Lison Dominique,Huaux François Toxicological sciences : an official journal of the Society of Toxicology Lung disorders induced by inhaled inorganic particles such as crystalline silica are characterized by chronic inflammation and pulmonary fibrosis. Here, we demonstrate the importance of type I interferon (IFN) in the development of crystalline silica-induced lung inflammation in mice, revealing that viruses and inorganic particles share similar signaling pathways. We found that instillation of silica is followed by the upregulation of IFN-beta and IRF-7 and that granulocytes (GR1(+)) and macrophages/dendritic cells (CD11c(+)) are major producers of type I IFN in response to silica. Two months after silica administration, both IFNAR- and IRF-7-deficient mice produced significantly less pulmonary inflammation and chemokines (KC and CCL2) than competent mice but developed similar lung fibrosis. Our data indicate that type I IFN contributes to the chronic lung inflammation that accompanies silica exposure in mice. Type I IFN is, however, dispensable in the development of silica-induced acute lung inflammation and pulmonary fibrosis. 10.1093/toxsci/kfq158
Suppressive oligodeoxynucleotides inhibit silica-induced pulmonary inflammation. Sato Takashi,Shimosato Takeshi,Alvord W Gregory,Klinman Dennis M Journal of immunology (Baltimore, Md. : 1950) Inhalation of silica-containing dust particles induces silicosis, an inflammatory disease of the lungs characterized by the infiltration of macrophages and neutrophils into the lungs and the production of proinflammatory cytokines, chemokines, and reactive oxygen species (ROS). Synthetic oligodeoxynucleotides (ODN) expressing "immunosuppressive motifs" were recently shown to block pathologic inflammatory reactions in murine models of autoimmune disease. Based on those findings, the potential of suppressive ODN to prevent acute murine silicosis was examined. In vitro studies indicate that suppressive ODN blunt silica-induced macrophage toxicity. This effect was associated with a reduction in ROS production and p47phox expression (a subunit of NADPH oxidase key to ROS generation). In vivo studies show that pretreatment with suppressive (but not control) ODN reduces silica-dependent pulmonary inflammation, as manifest by fewer infiltrating cells, less cytokine/chemokine production, and lower levels of ROS (p < 0.01 for all parameters). Treatment with suppressive ODN also reduced disease severity and improved the survival (p < 0.05) of mice exposed to silica. 10.4049/jimmunol.180.11.7648
Multinucleated giant cells in bronchoalveolar lavage. Kern Izidor,Kecelj Peter,Kosnik Mitja,Mermolja Milivoj Acta cytologica OBJECTIVE:To determine the frequency, morphology and possible diagnostic significance of multinucleated giant cells (MGC) in bronchoalveolar lavage (BAL). STUDY DESIGN:Retrospectively we examined 671 BAL specimens. Enlarged cells having > or = 10 nuclei were defined as MGC. Cytomorphologic features were described. BAL specimens containing MGC were grouped according to clinicohistologic diagnosis into sarcoidosis, asbestosis, other interstitial lung diseases and different chronic, noninterstitial lung diseases. RESULTS:MGC were present in 10.7% of BAL specimens and occurred in low numbers. MGC were classified into Langhans' or foreign-body-type MGC (LF-MGC), alveolar macrophage-like MGC (AM-MGC) and nonspecific MGC (NS-MGC). LF-MGC were found most often in patients with sarcoidosis. AM-MGC were found in all groups of patients. NS-MGC were found most often in patients with asbestosis and other interstital lung diseases. CONCLUSION:MGC in BAL are not encountered frequently and are not numerous. Based on cytomorphologic features, three types of MGC can be distinguished. 10.1159/000326545
Lipopolysaccharides may aggravate apoptosis through accumulation of autophagosomes in alveolar macrophages of human silicosis. Chen Shi,Yuan Juxiang,Yao Sanqiao,Jin Yulan,Chen Gang,Tian Wei,Xi Jinkun,Xu Zhelong,Weng Dong,Chen Jie Autophagy Silica dust mainly attacks alveolar macrophages (AMs) and increases the apoptosis of AMs in silicosis patients. However, it is still unclear whether autophagy is affected. Autophagy mainly has defensive functions in response to stress, contributing to cell survival in adverse conditions, and conversely it has also been implicated in cell death. Lipopolysaccharide (LPS) induces autophagy and apoptosis in macrophages. The role of LPS in autophagy and apoptosis in AMs of silicosis patients is unknown. In this study, we collected AMs from 53 male workers exposed to silica and divided them into an observer (control) group, and stage I, II and III patient groups. We found increased levels of LC3B, SQSTM1/p62 and BECN1,whereas the phosphorylation of MTOR,and levels of LAMP2, TLR4, MYD88, TICAM1, as well as the number of lysosomes decreased with the development of silicosis. LPS stimulation triggered autophagy and increased levels of SQSTM1 in AMs. The autophagy inhibitor, 3-methyladenine (3MA), inhibited LPS-induced apoptosis in the AMs of silicosis patients. Moreover, 3MA reversed the LPS-induced decrease in BCL2 and the increase in BAX and CASP3 levels in AMs. These results suggest that autophagosomes accumulate in AMs during silicosis progression. LPS can induce the formation of autophagosomes through a TLR4-dependent pathway, and LPS may exacerbate the apoptosis in AMs. Blockade of the formation of autophagosomes may inhibit LPS-induced apoptosis via the intrinsic apoptotic pathway in AMs. These findings describe novel mechanisms that may lead to new preventive and therapeutic strategies for pulmonary fibrosis. 10.1080/15548627.2015.1109765
Genome-wide DNA methylation analysis in lung fibroblasts co-cultured with silica-exposed alveolar macrophages. Li Juan,Yao Wu,Zhang Lin,Bao Lei,Chen Huiting,Wang Di,Yue Zhongzheng,Li Yiping,Zhang Miao,Hao Changfu Respiratory research BACKGROUND:Exposure to crystalline silica is considered to increase the risk of lung fibrosis. The primary effector cell, the myofibroblast, plays an important role in the deposition of extracellular matrix (ECM). DNA methylation change is considered to have a potential effect on myofibroblast differentiation. Therefore, the present study was designed to investigate the genome-wide DNA methylation profiles of lung fibroblasts co-cultured with alveolar macrophages exposed to crystalline silica in vitro. METHODS:AM/fibroblast co-culture system was established. CCK8 was used to assess the toxicity of AMs. mRNA and protein expression of collagen I, α-SMA, MAPK9 and TGF-β1 of fibroblasts after AMs exposed to 100 μg /ml SiO for 0-, 24-, or 48 h were determined by means of quantitative real-time PCR, immunoblotting and immunohistochemistry. Genomic DNA of fibroblasts was isolated using MeDIP-Seq to sequence. R software, GO, KEGG and Cytoscape were used to analyze the data. RESULTS:SiO exposure increased the expression of collagen I and α-SMA in fibroblasts in co-culture system. Analysis of fibroblast methylome identified extensive methylation changes involved in several signaling pathways, such as the MAPK signaling pathway and metabolic pathways. Several candidates, including Tgfb1 and Mapk9, are hubs who can connect the gene clusters. MAPK9 mRNA expression was significantly higher in fibroblast exposed to SiO in co-culture system for 48 h. MAPK9 protein expression was increased at both 24-h and 48-h treatment groups. TGF-β1 mRNA expression of fibroblast has a time-dependent manner, but we didn't observe the TGF-β1 protein expression. CONCLUSION:Tgfb1 and Mapk9 are helpful to explore the mechanism of myofibroblast differentiation. The genome-wide DNA methylation profiles of fibroblasts in this experimental silicosis model will be useful for future studies on epigenetic gene regulation during myofibroblast differentiation. 10.1186/s12931-017-0576-z
Crucial role of interleukin-1beta and nitric oxide synthase in silica-induced inflammation and apoptosis in mice. Srivastava Kamal D,Rom William N,Jagirdar Jaishree,Yie Ting-An,Gordon Terry,Tchou-Wong Kam-Meng American journal of respiratory and critical care medicine Crystalline silica stimulates macrophages in vitro to release interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), and nitric oxide (NO) and induces apoptosis of macrophages. Because the fibrogenic potential of a particulate paralleled its ability to induce apoptosis in macrophages, we investigated the underlying mechanisms by which IL-1beta and NO mediate apoptosis and inflammation in murine silicosis. First, we demonstrated that silica induced NO production and apoptosis in vitro using the IC-21 macrophage cell line. Both NO release and apoptosis could be inhibited by neutralizing anti-IL-1beta antibody or the NO synthase (NOS) inhibitor N(G)-nitro-L-arginine-methyl ester (L-NAME), demonstrating the requirement for IL-1beta-mediated NO release in silica-induced apoptosis. We exposed IL-1beta knockout (IL-1beta(-/-)) mice, inducible NOS knockout (iNOS(-/-)) mice, and wild-type mice to 250 mg/m(3) silica for 5 h/d for 10 d using an inhalation chamber. Exposure of wild-type mice to silica resulted in lung inflammation, apoptosis, and significantly larger and more numerous silicotic lesions than in IL-1beta(-/-) mice over a 12-wk course. We also exposed iNOS(-/-) mice via inhalation in the same protocol and compared with wild-type mice and demonstrated that iNOS(-/-) mice had significantly reduced apoptosis and inflammation. These results demonstrated an association between apoptosis and inflammation in murine silicosis and support a potential role for IL-1beta-dependent NO-mediated apoptosis in the evolution of silicosis. 10.1164/ajrccm.165.4.2106009
Macrophage-derived exosomal lncRNA MSTRG.91634.7 inhibits fibroblasts activation by targeting PINK1 in silica-induced lung fibrosis. Toxicology letters Silicosis is a fibrotic lung disease caused by the inhalation of free crystalline silica. Its pathogenesis is extremely complex and involves a variety of cells. Exosomes emerge as a favorable candidate for communication between cells. LncRNA is a major component transported by exosomes in many inflammatory diseases. However, the role of exosomal lncRNA in the pathogenesis of silicosis is still unclear. In this study, the decreased expression of a novel exosomal lncRNA MSTRG.91634.7 in silicosis patients was identified according to high-throughput sequencing. Then, this macrophage-derived exosomal lncRNA MSTRG.91634.7 could regulate the fibroblast's activation by targeting PINK1 in a co-culture system of THP-1 and MRC-5. Finally, the mouse was exposed to 3 mg/50 μL silica to set up the silicosis model. AAV-ov-Pink1 was intratracheally injected to overexpress PINK1 in mice lungs. Our results suggested that PINK1, the target protein of lncRNA MSTRG.91634.7, participated in restricting the silica-induced lung inflammation and fibrosis in mice. 10.1016/j.toxlet.2022.10.004
Differences in cellular and inflammatory cytokine profiles in the bronchoalveolar lavage fluid in bagassosis and silicosis. Zhai Rihong,Ge Xianmin,Li Helin,Tang Zhongquan,Liao Ruiqing,Kleinjans Jos American journal of industrial medicine BACKGROUND:Little is known about the crucial mediators involved in the inflammation and fibrogenesis in bagassosis. The aim of this study was to characterize the cellular and cytokine patterns in the airways of bagassosis and to compare these with silicosis subjects and controls. METHODS:Bronchoalveolar lavage (BAL) was performed in 11 patients with bagassosis, 16 cases with silicosis, and 8 controls. Differential cell counts, total protein concentration, TNF-alpha, IL-1beta, IL-5, IL-6, and IL-8 were analyzed in the bronchoalveolar lavage fluid (BALF). RESULTS:Bagassosis was characterized with hypercellularity with neutrophilia in BALF; while the predominant cell in the BALF in silicosis was macrophage. Compared with control subjects, increased TNF-alpha, IL-1beta, IL-8, and IL-6 levels were found in the BALFs in both bagassosis and silicosis. Furthermore, IL-6 levels in the BALF of silicosis subjects were significantly higher than that seen in bagassosis. In contrast, bagassosis had higher level of IL-8 in BALF than that in silicosis. Relationship among these parameters were found between IL-8 levels and neutrophils, lymphocytes and IL-1 beta in bagassosis, macrophages and IL-1beta in silicosis. No significant differences of total protein concentrations and IL-5 in BALF were found between controls or bagassosis, and silicosis. CONCLUSIONS:The findings of this study suggest that neutrophils, TNF-alpha, IL-1beta, IL-8, and IL-6 are involved in the pathogenesis in bagassosis. The mechanisms underline the different cellular and cytokine profiles in bagassosis and silicosis warrant further investigation. 10.1002/ajim.20051
Excess iron promotes emergence of foamy macrophages that overexpress ferritin in the lungs of silicosis patients. Respirology (Carlton, Vic.) BACKGROUND AND OBJECTIVE:Inhalation of high concentrations of respirable crystalline silica (RCS) can lead to silicosis. RCS contains varying levels of iron, which can cause oxidative stress and stimulate ferritin production. This study evaluated iron-related and inflammatory markers in control and silicosis patients. METHODS:A cohort of stone benchtop industry workers (n = 18) were radiologically classified by disease severity into simple or complicated silicosis. Peripheral blood and bronchoalveolar lavage (BAL) were collected to measure iron, ferritin, C-reactive protein, serum amyloid A and serum silicon levels. Ferritin subunit expression in BAL and transbronchial biopsies was analysed by reverse transcription quantitative PCR. Lipid accumulation in BAL macrophages was assessed by Oil Red O staining. RESULTS:Serum iron levels were significantly elevated in patients with silicosis, with a strong positive association with serum ferritin levels. In contrast, markers of systemic inflammation were not increased in silicosis patients. Serum silicon levels were significantly elevated in complicated disease. BAL macrophages from silicosis patients were morphologically consistent with lipid-laden foamy macrophages. Ferritin light chain (FTL) mRNA expression in BAL macrophages was also significantly elevated in simple silicosis patients and correlated with systemic ferritin. CONCLUSION:Our findings suggest that elevated iron levels during the early phases of silicosis increase FTL expression in BAL macrophages, which drives elevated BAL and serum ferritin levels. Excess iron and ferritin were also associated with the emergence of a foamy BAL macrophage phenotype. Ferritin may represent an early disease marker for silicosis, where increased levels are independent of inflammation and may contribute to fibrotic lung remodelling. 10.1111/resp.14230
BBC3 in macrophages promoted pulmonary fibrosis development through inducing autophagy during silicosis. Liu Haijun,Cheng Yusi,Yang Jian,Wang Wei,Fang Shencun,Zhang Wei,Han Bing,Zhou Zewei,Yao Honghong,Chao Jie,Liao Hong Cell death & disease Following inhalation into the lungs, silica particles are engulfed by alveolar macrophages, which triggers endogenous or exogenous apoptosis signaling pathways. As an inducer of apoptosis, the role of BBC3/PUMA (BCL2-binding component 3) in macrophages during silicosis remains unknown. Here, we exposed U937 cell-derived macrophages (UDMs) to SiO in vitro to explore the function of BBC3 in SiO-induced disease. We found that SiO induced increased BBC3 expression, as well as macrophage activation and apoptosis. Knockdown of Bbc3 with specific siRNA significantly mitigated the SiO-induced effects. In addition, our results clearly showed increased levels of autophagy in macrophages exposed to SiO. However, inhibition of BBC3 decreased the occurrence of autophagy. Furthermore, we observed that the blockade of autophagy with 3-MA, an autophagy inhibitor, inhibited SiO-induced macrophage activation and apoptosis. In contrast, rapamycin, an autophagy inducer, further enhanced the effects induced by SiO. The conditioned medium from macrophages exposed to SiO promoted the proliferation and migration of fibroblasts, and the inhibition of BBC3/autophagy reduced the effects of the conditioned medium on fibroblasts. In the mouse model of silicosis, Bbc3 knockout mice clearly exhibited decreased levels of autophagy and fibrosis progression. These results suggest that downregulation of BBC3 expression may become a novel therapeutic strategy for the treatment of silicosis. 10.1038/cddis.2017.78
About the Transient Effects of Synthetic Amorphous Silica: An In Vitro Study on Macrophages. International journal of molecular sciences Silica (either crystalline or amorphous) is widely used for different applications and its toxicological assessment depends on its characteristics and intended use. As sustained inflammation induced by crystalline silica is at the root of silicosis, investigating the inflammatory effects induced by amorphous silicas and their persistence is needed. For the development of new grades of synthetic amorphous silicas, it is also desirable to be able to understand better the factors underlying potential adverse effects. Therefore, we used an optimized in vitro macrophage system to investigate the effects of amorphous silicas, and their persistence. By using different amorphous silicas, we demonstrated that the main driver for the adverse effects is a low size of the overall particle/agglomerate; the second driver being a low size of the primary particle. We also demonstrated that the effects were transient. By using silicon dosage in cells, we showed that the transient effects are coupled with a decrease of intracellular silicon levels over time after exposure. To further investigate this phenomenon, a mild enzymatic cell lysis allowed us to show that amorphous silicas are degraded in macrophages over time, explaining the decrease in silicon content and thus the transiency of the effects of amorphous silicas on macrophages. 10.3390/ijms24010220
[Expression of serum cytokines in patients with pneumoconiosis by antibody chip]. Xia Yu-jing,Hao Feng-tong,Xu Li-ming,Xue Chang-jiang,Niu Ying-mei Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases OBJECTIVE:To investigate the changes in expression of serum cytokines in patients with pneumoconiosis using cytokine antibody chips (CACs). METHODS:The CAC technology was applied to measure the serum levels of 60 cytokines in 12 patients with pneumoconiosis and 3 normal controls. RESULTS:In the patients with pneumoconiosis, the highly expressed serum cytokines included interleukin (IL)-1α, IL-1β, IL-2, ILs 4-16, macrophage colony-stimulating factor, interferon-γ, tumor necrosis factor (TNF)-α, TNF-β, human bone morphogenetic protein-6, fibroblast growth factor-7, neurotrophin-3, and stem cell factor, and the lowly expressed serum cytokines included recombinant human I-309, monocyte chemoattractant protein (MCP)-1, MCP-2, MCP-3, MCP-4, macrophage inflammatory protein (MIP)-1-δ, and MIP-3-α. CONCLUSION:Patients with pneumoconiosis have changes in the expression of most serum cytokines.
Effects of chemical composition on the lung cell response to coal particles: Implications for coal workers' pneumoconiosis. Respirology (Carlton, Vic.) BACKGROUND AND OBJECTIVE:Coal mine dust has a complex and heterogeneous chemical composition. It has been suggested that coal particle chemistry plays a critical role in determining the pathogenesis of coal workers' pneumoconiosis (CWP). In this study, we aimed to establish the association between the detrimental cellular response and the chemical composition of coal particles. METHODS:We sourced 19 real-world coal samples. Samples were crushed prior to use to minimize the impact of particle size on the response and to ensure the particles were respirable. Key chemical components and inorganic compounds were quantified in the coal samples. The cytotoxic, inflammatory and pro-fibrotic responses in epithelial cells, macrophages and fibroblasts were assessed following 24 h of exposure to coal particles. Principal component analysis (PCA) and stepwise regression were used to determine which chemical components of the coal particles were associated with the cell response. RESULTS:The cytotoxic, inflammatory and pro-fibrotic response varied considerably between coal samples. There was a high level of collinearity in the cell responses and between the chemical compounds within the coal samples. PCA identified three factors that explained 75% of the variance in the cell response. Stepwise multiple regression analysis identified K O (p <0.001) and Fe O (p = 0.011) as significant predictors of cytotoxicity and cytokine production, respectively. CONCLUSION:Our data clearly demonstrate that the detrimental cellular effects of exposure to coal mine dusts are highly dependent on particle chemistry. This has implications for understanding the pathogenesis of CWP. 10.1111/resp.14246
Regulation of TLR4 in silica-induced inflammation: An underlying mechanism of silicosis. Chan Judy Yuet Wa,Tsui Joseph Chi Ching,Law Patrick Tik Wan,So Winnie Kwok Wei,Leung Doris Yin Ping,Sham Michael Mau Kwong,Tsui Stephen Kwok Wing,Chan Carmen Wing Han International journal of medical sciences Silicosis is an incurable lung disease affecting millions of workers in hazardous occupations. It is caused by chronic exposure to the dust that contains free crystalline silica. Silica-induced lung damage occurs by several main mechanisms including cell death by apoptosis, fibrosis and production of cytokines. However, the signal pathways involved in these mechanisms are not fully characterized. In this study, the toll-like receptor 4 (TLR4)-related signal pathway was examined in silica-treated U937-differentiated macrophages. The expression level of TLR4 was measured by both quantitative PCR and Western blot. Confirmation of the involvement of MyD88/TIRAP and NFκB p65 cascade was performed by Western blot. The secretion of cytokines IL-1β, IL-6, IL-10 and TNFα was measured by enzyme-linked immunosorbent assay. Our results showed that TLR4 and related MyD88/TIRAP pathway was associated with silica-exposure in U937-differentiated macrophages. Protein expression of TLR4, MyD88 and TIRAP was upregulated when the U937-differentiated macrophages were exposed to silica. However, the upregulation was attenuated when TLR4 inhibitor, TAK-242 was present. At different incubation times of silica exposure, it was found that NFκB p65 cascade was activated at 10-60 minutes. Release of cytokines IL-1β, IL-6, IL-10 and TNFα was induced by silica exposure and the induction of IL-1β, IL-6 and TNFα was suppressed by the addition of TAK-242. In conclusion, our study demonstrated that TLR4 and related MyD88/TIRAP pathway was involved in silica-induced inflammation in U937-differentiated macrophages. Downstream NFκB p65 cascade was activated within 1 hour when the U937-differentiated macrophages were exposed to silica. The better understanding of early stage of silica-induced inflammatory process may help to develop earlier diagnosis of silicosis. 10.7150/ijms.24715
Fibroblast-derived CXCL14 aggravates crystalline silica-induced pulmonary fibrosis by mediating polarization and recruitment of interstitial macrophages. Journal of hazardous materials Exposure to crystalline silica (CS) particles in worksites and dwellings can lead to silicosis due to excessive fibroblast activation. Considering their immuno-regulatory activities, the contribution of pulmonary fibroblasts in the progression of silicosis has not been thoroughly characterized. Here, we demonstrate that exposure of the lung to CS particles leads to the upregulation of fibroblast-derived C-X-C motif chemokine ligand 14 (CXCL14). By employing an in vitro co-culture system, we demonstrated activated fibroblasts recruited bone marrow-derived macrophages (BMDMs) and favored alternative macrophage polarization (M2) mediated by CXCL14. Furthermore, in vivo studies echoed that systemic CXCL14 neutralizing or fibroblast-specific Cxcl14 knockout proved CXCL14 was indispensable for the recruitment and phenotype alteration of lung macrophages, especially interstitial macrophages (IMs), under stimulation by CS particles. Mechanistically, we showed that GLI2 and p21-mediated cellular senescence were mediators of CXCL14 production following CS exposure. Accordingly, GLI2 blockage and countering cellular senescence by reviving PINK1-mediated mitophagy may be efficient strategies to reduce CXCL14 expression in activated fibroblasts during silicosis. Our findings emphasize the immuno-regulatory function of fibroblasts in silicosis via CXCL14, providing intervention targets for CS-induced pulmonary fibrosis. 10.1016/j.jhazmat.2023.132489
[Giant cell interstitial pneumonia: a case report and literature review]. Cai Hou-rong,Cao Min,Meng Fan-qing,Wei Jing-yi,Hou Jie Zhonghua jie he he hu xi za zhi = Zhonghua jiehe he huxi zazhi = Chinese journal of tuberculosis and respiratory diseases OBJECTIVE:To highlight the characteristics of giant cell interstitial pneumonia (GIP). METHODS:The clinical, radiological and pathological data of a patient with GIP confirmed by open lung biopsy were presented, and relevant literatures were reviewed. RESULTS:Patients with GIP usually had a history of exposure to metal dust. Clinical presentations include cough and dyspnea on exertion, and pulmonary function testing showed a restrictive abnormality. On chest radiography and high-resolution CT scans, it presents as bilateral areas of ground-glass attenuation, areas of consolidation, diffuse small nodules, extensive reticular opacities and traction bronchiectasis. The main pathological findings include a desquamative interstitial pneumonia (DIP)-like reaction with intra-alveolar macrophages and numerous large multinucleated histiocytes that ingested inflammatory cells were admixed with macrophages. The finding of GIP is almost pathognomonic for hard metal pneumoconiosis. CONCLUSIONS:GIP is a very rare chronic interstitial pneumonia, and has no characteristic clinical manifestations. Radiographic findings are similar to other idiopathic interstitial pneumonias. Meticulous history taking on occupational exposure is important for the diagnosis of GIP.
Nicotine induces apoptosis through exacerbation of blocked alveolar macrophage autophagic degradation in silicosis. Chen Shi,Tan Shiyi,Yang Shang,Chen Gang,Zhu Li,Sun Zhiqian,Li Haibin,Yao Sanqiao Toxicology letters Silica dust mainly attacks alveolar macrophages (AMs). The apoptosis of AMs is correlated with the progress of silicosis. Our previous study showed that autophagic degradation was blocked in AMs from silicosis patients. However, the effects of nicotine on AM autophagy and apoptosis in silicosis are unknown. In this study, we collected AMs from twenty male workers exposed to silica and divided them into observer and silicosis patient groups, according to the tuberous pathological changes observed by X-ray. The AMs from both groups were exposed to nicotine. We found increased levels of LC3, p62, and cleaved caspase-3, decreased levels of LAMP2, and damaged lysosomes after nicotine stimulation of the AMs from both groups. We also found that the autophagy inhibitor 3-methyladenine (3MA) inhibited nicotine-induced apoptosis in the AMs. Furthermore, 3MA reversed both the nicotine-induced decrease in Bcl-2 and the increase in Bax in both groups. These results suggest that nicotine may induce apoptosis by blocking AM autophagic degradation in human silicosis. 10.1016/j.toxlet.2020.09.019
Rare pneumoconiosis induced by long-term amorphous silica exposure: the histological characteristics and expression of cyclooxygenase-2 as an antifibrogenic mediator in macrophages. Kumasaka Toshio,Akaike Yasushi,Nakamura Osamu,Yamazaki Kazuma,Moriyama Hiroshi,Takemura Tamiko Pathology international Pneumoconiosis induced by non-crystalline silica is considered rare, although silicosis resulting from contact with crystalline silica is a well-known hazard associated with progressive pulmonary fibrosis. Here we describe a patient with pneumoconiosis induced by diatomaceous earth composed of amorphous silica detected by two-dimensional imaging of chemical elements. The histology revealed that the disease was characterized by a granulomatous reaction in the lung. A large number of macrophages laden with yellow and black pigments accumulated in alveolar spaces and were incorporated into the interstitial sites. Bronchiolar walls were destroyed by palisade macrophages, suggesting airflow obstruction. Packed macrophages adhering to and covering the denuded interstitium indicated that macrophages might be incorporated into pulmonary interstitium in this fashion. Immunohistochemistry showed that cyclooxygenase-2, an antifibrogenic mediator, was intensely expressed in the macrophages compared with macrophages in control lungs. No birefringent material was found in the tissues. When two-dimensional analysis of chemical elements was performed using an electron probe microanalyzer with a wavelength-dispersive spectrometer, the resultant fine mapping of silicon and oxygen on the tissue indicated that the pigments phagocytosed by macrophages corresponded to amorphous silica. In conclusion, two-dimensional analysis of elements is very useful for pathologists in correlating the presence of chemical elements with histological changes. 10.1111/j.1440-1827.2011.02715.x
Altered M1/M2 polarization of alveolar macrophages is involved in the pathological responses of acute silicosis in rats in vivo. Toxicology and industrial health Alveolar macrophages play a vital role in the development of acute silicosis, but the dynamic changes of M1 and/or M2 phenotypes have not been elucidated. In this study, acute silicosis models of rat were established by a one-time dusting method, and the rats were sacrificed after 1, 3, 7, 14, and 28 days. The polarity states of macrophages were assessed by measuring the M1/M2 marker genes of alveolar macrophages and the M1/M2 marker proteins in bronchoalveolar lavage fluid. The pathological changes of lung tissues were examined with hematoxylin and Eosin and Masson's trichrome staining. Our results showed that in the early stages, alveolar macrophages were mainly polarized into M1; with time, the polarization of M2 gradually became dominant. Microscopic sections showed significant pathological responses of inflammation and fibrosis. This work suggested that the alteration of alveolar macrophage polarization was involved in the lung pathologic responses to acute silicosis. 10.1177/07482337221136949
The aggravate role of exosomal circRNA11:120406118|12040782 on macrophage pyroptosis through miR-30b-5p/NLRP3 axis in silica-induced lung fibrosis. International immunopharmacology Silica dust inhalation could lead to silicosis, and there is no specific biomarker for its early diagnosis and no effective treatment due to the lack of research on its pathogenesis. The homeostasis of macrophages was considered to be crucial during the development of silicosis from persistent chronic inflammation to irreversible fibrosis. However, its regulatory mechanism and the communication between macrophages and others are still not clear. Exosomal circRNAs emerge as favorable candidates for cellular communication. Therefore, our study aimed to illustrate the regulatory mechanism of silicosis from the view of exosomal circRNAs. Our study identified a novel exosomal circRNA, circRNA11:120406118|12040782, in the peripheral serum of silicosis patients. Furthermore, the detailed role of circRNA11:120406118|12040782 was investigated both in silicosis mouse model and in silica-stimulated macrophages and fibroblasts. On the one hand, circRNA11:120406118|12040782 was shown to regulate silica-stimulated macrophage pyroptosis through circRNA11:120406118|12040782/miR-30b-5p/NLRP3 network. And this macrophage-derived cirRNA could promote the activation of fibroblasts. On the other hand, overexpressing miR-30b-5p, the crucial component of circRNA11:120406118|12040782/miR-30b-5p/NLRP3 regulatory network, could inhibit pyroptosis and attenuate silica-induced lung inflammation and fibrosis in mice. Our findings suggested that exosomal circRNA11:120406118|12040782 could aggravate NLRP3-mediated macrophages pyroptosis through sponging miR-30b-5p in silicosis development, which provide an experimental basis and shed light on the early diagnosis and treatment of silicosis. 10.1016/j.intimp.2022.109476
Immunocytochemical characterization of lung macrophage surface phenotypes and expression of cytokines in acute experimental silicosis in mice. Orfila C,Lepert J C,Gossart S,Frisach M F,Cambon C,Pipy B The Histochemical journal The expression of the surface phenotypical profile and the cytokines TNF-alpha and IL-1beta from murine lung macrophages was studied in parenchymal lung tissue and bronchoalveolar fluid of mice, over a 2-week period, following a single intratracheal instillation of silica. The acute inflammatory reaction, confirmed by a significant augmentation of four times the control values of the number of macrophages recovered by lavage from experimental animals, was followed by organized granulomas in the interstitium. The immunohistochemical analysis of lung tissue sections after silica instillation demonstrated the increased alveolar and interstitial tissue expression of all surface antigens and cytokines studied, mainly Mac-1, F4/80 antigens, TNF-alpha and IL-1beta, which were occasionally observed in normal uninjected and saline-treated mice. These findings show that, after silica instillation, the expression of surface phenotypical markers of lung macrophages increased, and this change was concomitantly associated with an increased expression of the cytokines TNF-alpha and IL-1beta. These changes support the conclusion that an influx of the newly recruited and activated macrophage population, with a different phenotype, is induced by treatment during inflammation. The populational changes involve difference in functional activity and enhance TNF-alpha and IL-1beta expression. These cytokines, produced in the silicosis-induced inflammatory process, are associated with the development of fibrosis and may contribute to disease severity.
Spontaneous and stimulated release of tumor necrosis factor-alpha (TNF) from blood monocytes of miners with coal workers' pneumoconiosis. Borm P J,Palmen N,Engelen J J,Buurman W A The American review of respiratory disease It is generally accepted that fibrotic lung diseases are mediated by macrophage-derived cytokines. We investigated the release of the monokine tumor necrosis factor-alpha (TNF) from blood monocytes in a group of 66 coal miners and 12 non-dust-exposed individuals. Twenty-seven miners had simple Coal Workers' Pneumoconiosis (CWP). Control miners (n = 39) were matched with respect to age, years underground, and smoking. Monocytes were assayed for TNF release, spontaneously or in response to soluble (endotoxin) or particulate (coal mine dust, silica) stimulation. TNF was measured with a TNF-specific ELISA. Monocytes of all subjects responded to stimulants by the release of TNF. Dust-exposed controls' monocytes revealed higher TNF release as compared to normal controls. The greatest discriminator between control miners and cases (CWP) was coal mine dust-induced TNF release. Interestingly, the largest difference was observed between controls and those cases with a small number of opacities (0/1, 1/0, 1/1, and 1/2), giving an odds ratio of 6.3 to find an individual with a "high" dust-induced TNF release in the patient group. 10.1164/ajrccm/138.6.1589
[The role of pulmonary macrophages in the development of silicosis]. Kong Hai-xia,Chen Juan-juan,Liu Wei Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases
Macrophage activity in asbestos related diseases. Tarkowski M,Górski P Polish journal of occupational medicine and environmental health This paper indicates some immunological aspects of asbestos-related diseases and especially concerns the activity of macrophages--cells of immunological surveillance. Macrophages establish a very important population of cells which initiate or suppress specific immune response; they are responsible for effective T-cell activation, express antitumour activity. The process of lung fibrosis generated by the inhalation and deposition of asbestos fibres is also closely related to macrophage activity. An open question which is still to be resolved concerns asbestos-induced fibrosis; it may arise as a consequence of tissue injury and repair or change collagen synthesis. Another question is, to what extent macrophages may be protective cells and when they become undesirable? Since their overstimulation or damage in the case of chronic exposure to asbestos dust may be the reason of the increased release of inflammatory mediators, reactive oxygen intermediates which may in turn cause tissue injury, fibrosis or, in final effect, cancer. If so, we could then say that lung response (expressed by e.g. alveolar macrophage activity) to chemical insult may cause further damage to this tissue.
Imipramine blocks acute silicosis in a mouse model. Biswas Rupa,Trout Kevin L,Jessop Forrest,Harkema Jack R,Holian Andrij Particle and fibre toxicology BACKGROUND:Inhalation of crystalline silica is associated with pulmonary inflammation and silicosis. Although silicosis remains a prevalent health problem throughout the world, effective treatment choices are limited. Imipramine (IMP) is a FDA approved tricyclic antidepressant drug with lysosomotropic characteristics. The aim of this study was to evaluate the potential for IMP to reduce silicosis and block phagolysosome membrane permeabilization. METHODS:C57BL/6 alveolar macrophages (AM) exposed to crystalline silica ± IMP in vitro were assessed for IL-1β release, cytotoxicity, particle uptake, lysosomal stability, and acid sphingomyelinase activity. Short term (24 h) in vivo studies in mice instilled with silica (± IMP) evaluated inflammation and cytokine release, in addition to cytokine release from ex vivo cultured AM. Long term (six to ten weeks) in vivo studies in mice instilled with silica (± IMP) evaluated histopathology, lung damage, and hydroxyproline content as an indicator of collagen accumulation. RESULTS:IMP significantly attenuated silica-induced cytotoxicity and release of mature IL-1β from AM in vitro. IMP treatment in vivo reduced silica-induced inflammation in a short-term model. Furthermore, IMP was effective in blocking silica-induced lung damage and collagen deposition in a long-term model. The mechanism by which IMP reduces inflammation was explored by assessing cellular processes such as particle uptake and acid sphingomyelinase activity. CONCLUSIONS:Taken together, IMP was anti-inflammatory against silica exposure in vitro and in vivo. The results were consistent with IMP blocking silica-induced phagolysosomal lysis, thereby preventing cell death and IL-1β release. Thus, IMP could be therapeutic for silica-induced inflammation and subsequent disease progression as well as other diseases involving phagolysosomal lysis. 10.1186/s12989-017-0217-1
Lipid Uptake by Alveolar Macrophages Drives Fibrotic Responses to Silica Dust. Hou Xiaomin,Summer Ross,Chen Ziying,Tian Ying,Ma Jingjing,Cui Jie,Hao Xiaohui,Guo Lingli,Xu Hong,Wang Hongli,Liu Heliang Scientific reports Silicosis is a common occupational disease and represents a significant contributor to respiratory morbidity and mortality worldwide. Lipid-laden macrophages, or foam cells, are observed in the lungs of patients with silicosis but the mechanisms mediating their formation remain poorly understood. In this study, we sought to elucidate the mechanisms by which silica promotes foam cell formation in the lung, and to determine whether uptake of lipids alone is sufficient to drive TGF-β production by alveolar macrophages. Consistent with previous reports, we found that foam cells were markedly increased in the lungs of patients with silicosis and that these findings associated with both higher levels of intracellular lipid levels (oxidized LDL, ox-LDL) and elevated transcript levels for the lipid scavenger receptor CD36 and the nuclear receptor PPARγ. Employing a rat alveolar macrophage cell line, we found that exposure to silica dust or ox-LDL alone had a modest effect on the induction of foam cell formation and only silica was capable of inducing the production of TGF-β. In contrast, foam cell formation and TGF-β production were both dramatically increased when cells were exposed to a combination of silica dust and ox-LDL. Moreover, we found that these endpoints were markedly attenuated by either blocking CD36 or inhibiting the activity of PPARγ. Altogether, our findings suggest that foam cell formation and TGF-β production are driven by the simultaneous uptake of silica and lipids in alveolar macrophages and that strategies aimed at blocking lipid uptake by alveolar macrophages might be effective in ameliorating fibrotic responses to silica in the lung. 10.1038/s41598-018-36875-2
Macrophage-associated responses to chrysotile. Oberdörster G The Annals of occupational hygiene The different pulmonary macrophage (airway macrophages, alveolar macrophages, interstitial macrophages, intravascular macrophages, pleural macrophages) are an important part of the lungs' defences against non-fibrous and fibrous particles deposited by inhalation. The first line of defence is airway macrophages and alveolar macrophages (AM) which initially interact with deposited chrysotile fibres and subsequently release a number of mediators including growth regulatory and chemotactic proteins, arachidonic acid metabolites, proteases, NO and active oxygen species, all of which can affect--also adversely--specific target cells in the lung. Mechanical clearance via the mucociliary escalator and dissolution of phagocytized fibres in the acidic milieu of the phagolysosome in pulmonary macrophages are further important functions of AM. Chrysotile appears to be more toxic or at least has the same toxicity to AM as amphibole fibres when doses of a similar mass are administered. However, on a fibre number basis chrysotile appears to be less toxic to AM. The importance of the appropriate dose parameter--i.e. fibre mass, number or surface area--needs to be considered in in vitro as well as in in vivo studies. Short chrysotile fibres are cleared from rat lungs very rapidly whereas longer ones are cleared at a much slower rate. This is due to efficient phagocytosis of short fibres by AM accompanied by dissolution in the acidic milieu of the phagolysosome. Prediction of chrysotile clearance in primate lung based on results from rat studies result in an overall retention half-time of approximately 105 days, based on which no long-term accumulation of chrysotile in the primate lung is to be expected. Long-term inhalation studies in baboons exposed to chrysotile confirm the very fast build up of a low steady-state lung burden, consistent with a pulmonary retention half-time for chrysotile of approximately 90 days. Despite the fast clearance and low pulmonary accumulation of chrysotile, the resulting effects, such as asbestosis, were found to be of the same severity in rats as those induced by amphibole exposure. In the amphibole-exposed rats, the fibre lung burden continued to increase with exposure time. The potential contamination of chrysotile with tremolite cannot explain these results since there was no increased pulmonary accumulation of fibres in the chrysotile-exposed rats. Effects due to lung particle overload are not to be expected in long-term chrysotile inhalation studies since no accumulation occurs and one needs to distinguish clearly between a volumetric overload of the AM (not occurring with chrysotile) and failed or partial phagocytosis of long fibres.(ABSTRACT TRUNCATED AT 400 WORDS) 10.1093/annhyg/38.4.601
Silica-induced NLRP3 inflammasome activation in vitro and in rat lungs. Peeters Paul M,Eurlings Irene M J,Perkins Timothy N,Wouters Emiel F,Schins Roel P F,Borm Paul J A,Drommer Wolfgang,Reynaert Niki L,Albrecht Catrin Particle and fibre toxicology RATIONALE:Mineral particles in the lung cause inflammation and silicosis. In myeloid and bronchial epithelial cells the inflammasome plays a role in responses to crystalline silica. Thioredoxin (TRX) and its inhibitory protein TRX-interacting protein link oxidative stress with inflammasome activation. We investigated inflammasome activation by crystalline silica polymorphs and modulation by TRX in vitro, as well as its localization and the importance of silica surface reactivity in rats. METHODS:We exposed bronchial epithelial cells and differentiated macrophages to silica polymorphs quartz and cristobalite and measured caspase-1 activity as well as the release of IL-1β, bFGF and HMGB1; including after TRX overexpression or treatment with recombinant TRX. Rats were intratracheally instilled with vehicle control, Dörentruper quartz (DQ12) or DQ12 coated with polyvinylpyridine N-oxide. At days 3, 7, 28, 90, 180 and 360 five animals per treatment group were sacrificed. Hallmarks of silicosis were assessed with Haematoxylin-eosin and Sirius Red stainings. Caspase-1 activity in the bronchoalveolar lavage and caspase-1 and IL-1β localization in lung tissue were determined using Western blot and immunohistochemistry (IHC). RESULTS:Silica polymorphs triggered secretion of IL-1β, bFGF and HMGB1 in a surface reactivity dependent manner. Inflammasome readouts linked with caspase-1 enzymatic activity were attenuated by TRX overexpression or treatment. At day 3 and 7 increased caspase-1 activity was detected in BALF of the DQ12 group and increased levels of caspase-1 and IL-1β were observed with IHC in the DQ12 group compared to controls. DQ12 exposure revealed silicotic nodules at 180 and 360 days. Particle surface modification markedly attenuated the grade of inflammation and lymphocyte influx and attenuated the level of inflammasome activation, indicating that the development of silicosis and inflammasome activation is determined by crystalline silica surface reactivity. CONCLUSION:Our novel data indicate the pivotal role of surface reactivity of crystalline silica to activate the inflammasome in cultures of both epithelial cells and macrophages. Inhibitory capacity of the antioxidant TRX to inflammasome activation was evidenced. DQ12 quartz exposure induced acute and chronic functional activation of the inflammasome in the heterogeneous cell populations of the lung in associated with its crystalline surface reactivity. 10.1186/s12989-014-0058-0
Mixed Pneumoconiosis Associated with Diffuse Pulmonary Ossification in Wild Coyotes (Canis latrans). Nevárez-Garza Alicia M,Garza-Arredondo Aimé J,Zamora-Avila Diana E,Moreno-Degollado Gustavo,Rodriguez-Tovar Luis E Journal of comparative pathology Mixed pneumoconiosis is a pulmonary disease associated with several inhaled mineral irritants. Dust was found in the alveolar macrophages, alveolar and bronchial walls and pulmonary interstitial tissue of two female coyotes (Canis latrans). The dust contained large amounts of silica, coal, iron and copper particles, which were associated with severe pulmonary disease. Lung injury in the animals was characterized by pulmonary nodules, severe interstitial fibrosis, alveolar hyperplasia and bone formation within alveolar spaces. Coyotes inhaled mineral dust while roaming a field close to three mineral extraction zones. To our knowledge, this is the first report of the concomitant inhalation of multiple minerals in association with diffuse pulmonary ossification in the pulmonary parenchyma of two wild canine animals. 10.1016/j.jcpa.2021.10.001
Profiling of metabolites, proteins, and protein phosphorylation in silica-exposed BEAS-2B epithelial cells. PloS one Silicosis is an uncurable occupational disease induced by crystalline silica. Increased prevalence of silicosis has resulted in the increased need for development of treatment options. Although macrophages respond first to silica, epithelial cells are also involved in silicosis. However, changes in protein and metabolite levels have not been reported simultaneously. We used mass spectrometry to profile changes in metabolites, proteins, and phosphorylation in silica-exposed BEAS-2B epithelial cells. Silica exposure increased TCA cycle, alanine, aspartate and glutamate metabolism, and aerobic glycolysis activity. In addition, protein levels in the endoplasmic reticulum were significantly altered, and phosphorylation of MAPK signaling proteins was increased. The results of this study increased understanding the role of epithelial cells in silicosis. 10.1371/journal.pone.0273034
Fas ligand triggers pulmonary silicosis. Borges V M,Falcão H,Leite-Júnior J H,Alvim L,Teixeira G P,Russo M,Nóbrega A F,Lopes M F,Rocco P M,Davidson W F,Linden R,Yagita H,Zin W A,DosReis G A The Journal of experimental medicine We investigated the role of Fas ligand in murine silicosis. Wild-type mice instilled with silica developed severe pulmonary inflammation, with local production of tumor necrosis factor (TNF)-alpha, and interstitial neutrophil and macrophage infiltration in the lungs. Strikingly, Fas ligand-deficient generalized lymphoproliferative disease mutant (gld) mice did not develop silicosis. The gld mice had markedly reduced neutrophil extravasation into bronchoalveolar space, and did not show increased TNF-alpha production, nor pulmonary inflammation. Bone marrow chimeras and local adoptive transfer demonstrated that wild-type, but not Fas ligand-deficient lung macrophages recruit neutrophils and initiate silicosis. Silica induced Fas ligand expression in lung macrophages in vitro and in vivo, and promoted Fas ligand-dependent macrophage apoptosis. Administration of neutralizing anti-Fas ligand antibody in vivo blocked induction of silicosis. Thus, Fas ligand plays a central role in induction of pulmonary silicosis. 10.1084/jem.194.2.155
Inhibition of Gas6 promotes crystalline silica-induced inflammatory response of macrophages via blocking autophagy flux. Environmental toxicology Inhalation of crystalline silica (CS) can cause silicosis, which is one of the most serious interstitial lung diseases worldwide. Autophagy dysfunction is an essential step in silicosis progression. In this study, we aim to identify the effect of growth arrest-specific protein 6 (Gas6) during autophagy induction and macrophage inflammatory response caused by CS. After RAW 264.7 macrophages exposed to CS, the levels of Gas6 and autophagy markers (p62, Beclin1, and LC3-II/LC3-I) were increased, accompanied with enhanced inflammatory cytokines secretion. Using autophagy activator (rapamycin) repressed, whereas autophagy inhibitor (3-methyladenine) promoted inflammatory cytokines release. Besides, inhibition of Gas6 aggravated CS-induced inflammatory response, and autophagy inhibition facilitated the promoted effect of Gas6 silencing, resulting in elevated expression of inflammatory cytokines. These findings reveal the protective effects of Gas6 and autophagy in macrophages in response to CS exposure, and highlight the autophagy regulated by Gas6 may be a potential prevention target for CS-induced lung inflammatory response. 10.1002/tox.23539
Potential biomarker of coal workers' pneumoconiosis. Kim K A,Lim Y,Kim J H,Kim E K,Chang H S,Park Y M,Ahn B Y Toxicology letters It is well known that various cytokines and growth factors secreted from macrophages/monocytes play the key role in the pathogenesis of pneumoconiosis. These can act as biosensors for the prediction of pneumoconiosis. To evaluate which cytokines can be used as sensitive biomarkers in pneumoconiosis, we measured tumor necrosis factor-alpha (TNF-alpha), interleukin-8 (IL-8) and platelet-derived growth factor-AA (PDGF-AA) in supernatant of monocytes with or without coal dust (5 mg/ml) and serum in 42 coal miners with pneumoconiosis and ten healthy control. The coal-stimulated release of TNF-alpha and IL-8 from blood monocytes was significant increased in pneumoconiosis patients compared with controls. The level of TNF-alpha and IL-8 in blood serum was higher in subjects with pneumoconiosis than in controls.
On the relationship between activation and breakdown of macrophages in the pathogenesis of silicosis (an overview). Privalova L I,Katsnelson B A,Sharapova N Y,Kislitsina N S La Medicina del lavoro Silica particles cause considerable damage to macrophages resulting in their eventual breakdown. At the same time, the development of silicosis involves a number of mechanisms associated with the activation of macrophages. In suggesting schemes for the pathogenesis of this disease many authors associate the central part with activation, completely neglecting damage to cells. Our experiments have shown, however, that much of the activation phenomena could be reproduced in vitro or in vivo by exposing macrophages to macrophage breakdown products. Alternatively, the secondary character of activation is demonstrated by the fact that it reveals itself only at silica doses which cause part of the cells to lose their viability in the same culture. Our data show that the range of macrophage activation phenomena which could be considered as secondary with respect to the breakdown of cells includes the production of neutrophil attractants, enhanced co-operation with T lymphocytes, increase in phagocytic activity, enhancement of cellular O2 consumption and peroxidation, an increase in the activity of dehydrogenases, reduction in the activity of 5'-nucleotidase, and some other effects. Although not denying that small silica doses may be able to exert a direct activating influence upon the macrophage we do, however, believe that the most important and primary role in the pathogenesis of silicosis is played by the damage to and the breakdown of this cell.
Effects of silica, asbestos, and other particles on macrophage and neutrophil lysosomes. Allison A C,Morgan D M Frontiers of biology
Beryllium-stimulated apoptosis in macrophage cell lines. Sawyer R T,Fadok V A,Kittle L A,Maier L A,Newman L S Toxicology In vitro stimulation of bronchoalveolar lavage cells from patients with chronic beryllium disease (CBD) induces the production of TNF-alpha. We tested the hypothesis that beryllium (Be)-stimulated TNF-alpha might induce apoptosis in mouse and human macrophage cell lines. These cell lines were selected because they produce a range of Be-stimulated TNF-alpha. The mouse macrophage cell line H36.12j produces high levels of Be-stimulated TNF-alpha. The mouse macrophage cell line P388D.1 produces low, constitutive, levels of TNF-alpha and does not up-regulate Be-stimulated TNF-alpha production. The DEOHS-1 human CBD macrophage cell line does not produce constitutive or Be-stimulated TNF-alpha. Apoptosis was determined by microscopic observation of propidium iodide stained fragmented nuclei in unstimulated and BeSO(4)-stimulated macrophage cell lines. BeSO(4) induced apoptosis in all macrophage cell lines tested. Beryllium-stimulated apoptosis was dose-responsive and maximal after 24 h of exposure to 100 microM BeSO(4). In contrast, unstimulated and Al(2)(SO(4))(3)-stimulated macrophage cell lines did not undergo apoptosis. The general caspase inhibitor BD-fmk inhibited Be-stimulated macrophage cell line apoptosis at concentrations above 50 microM. Our data show that Be-stimulated macrophage cell line apoptosis was caspase-dependent and not solely dependent on Be-stimulated TNF-alpha levels. We speculate that the release of Be-antigen from apoptotic macrophages may serve to re-introduce Be material back into the lung microenvironment, make it available for uptake by new macrophages, and thereby amplify Be-stimulated cytokine production, promoting ongoing inflammation and granuloma maintenance in CBD.
Human alveolar macrophage cytokine release in response to in vitro and in vivo asbestos exposure. Perkins R C,Scheule R K,Hamilton R,Gomes G,Freidman G,Holian A Experimental lung research The lung macrophage is proposed to be involved in the development of asbestos-induced pulmonary fibrosis. Knowledge of the effects of long-term asbestos exposure on lung macrophage cytokine release should better define the role of the macrophage in fibrogenesis. This study examines the effects of acute in vitro asbestos exposure and chronic in vivo asbestos exposure on human alveolar macrophage cytokine release. As indicators of asbestos-induced macrophage activation, the cellular release of IL-1 beta, TNF-alpha, IL-6, GM-CSF, and PGE2 was measured during a 24-h in vitro culture. Alveolar macrophages from normal volunteers were cultured in vitro with chrysotile asbestos. Of the factors measured, only TNF-alpha was elevated in response to asbestos exposure. Alveolar macrophages from asbestos-exposed individuals were placed into one of two groups based on their exposure history. These two groups were matched for age, smoking history, and diagnosis; none met the criteria for asbestosis. Cells isolated from subjects that had been exposed to asbestos for more than 10 years secreted enhanced basal amounts of IL-1 beta, TNF-alpha, IL-6, and PGE2, while those who had been exposed for less than 10 years did not. The results indicate that while asbestos had minimal acute effects on cytokine production by the human alveolar macrophage, intense, chronic exposure to asbestos leads to the enhanced basal release of significant amounts of several cytokines that have activity for the fibroblast, even in the absence of overt fibrosis. 10.3109/01902149309071080
SiO stimulates macrophage stress to induce the transformation of lung fibroblasts into myofibroblasts and its relationship with the sphingomyelin metabolic pathway. Liu Jing,Guan Lan,Wang Erjin,Schuchman Edward H,He Xingxuan,Zeng Ming Journal of applied toxicology : JAT Silicosis is a serious occupational disease with the highest incidence in China. However, its pathogenesis has not been fully elucidated. Studies have shown that the sphingomyelin signaling pathway may play an important role in different fibrotic diseases but its role in silicosis-mediated fibrosis is still unclear. In this study, the supernatant of human peripheral blood mononuclear cell line (THP-1)-derived macrophages exposed to silica (SiO ) was used to stimulate the transformation of human embryonic lung fibroblast cell line (HFL-1) into myofibroblasts, and the intervention effect of recombinant human acid ceramidase (rAC) was observed. The results showed that SiO stimulated the production of reactive oxygen species and malondialdehyde in the supernatant of THP-1-derived macrophages and increased the secretion of TGF-β1, TNF-α, and IL-8. In addition, we found that the expression levels of α-SMA, FN, Col I, and Col III in HFL-1 cells increased. Meanwhile, the activities of ASMase and ACase and the expression levels of Cer, Sph, and S1P were increased. Intervention by rAC can suppress these changes to different degrees. In conclusion, the present study shows that SiO dust poisoning may stimulate HFL-1 cell differentiation into myofibroblasts by inducing oxidative stress in THP-1-derived macrophages, thereby promoting the secretion of a variety of inflammatory factors and activating the sphingolipid signaling pathway in HFL-1 cells. Exogenous rAC can effectively interfere with the stimulation of HFL-1 cells by silica in vitro. 10.1002/jat.4148
Bronchoalveolar cell differential count and the number of asbestos bodies correlate with survival in patients with asbestosis. Keskitalo Eerika,Varis Laura,Bloigu Risto,Kaarteenaho Riitta Occupational and environmental medicine OBJECTIVES:To determine cell differential counts and the number of asbestos bodies (ABs) in bronchoalveolar lavage (BAL) fluid obtained from patients with asbestosis, and to correlate the results with their survival. METHODS:The BAL cell differential counts and ABs from 91 patients with asbestosis were determined. The BAL cell differential counts were analysed in relation to smoking status. BAL cell differential counts and the number of ABs were correlated with the patients' survivals. RESULTS:A neutrophilic cell pattern was observed independently of smoking habits with both Papanicolau (8.4%) and May-Grunwald-Giemsa (6.5%) staining. Smoking and a high number of ABs (>2 AB/mL) were associated with high total cell counts and high macrophage and low lymphocyte differential counts. The median survival of the patients was 131.8 months. Shortened survival was associated with high numbers of ABs (78 vs 165 months; p=0.042) and low lymphocyte (77 vs 179 months; p=0.005), high neutrophil (102 vs 180 months; p=0.016) and high eosinophil (104 vs170 months; p=0.007) differential counts. CONCLUSION:A neutrophilic cell pattern was evident in BAL from patients with asbestosis. Smoking and ABs both affected the total cell count and the macrophage and lymphocyte differential counts. Several BAL parameters associated with patient survival, suggesting that BAL cell count analyses could be used in the estimation of the prognosis of patients with asbestosis. 10.1136/oemed-2018-105606
[Research of epigenetic modifications in pathogenesis of pneumoconiosis]. Wang H,Hu J A Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases Pneumoconiosis is the most common and severe occupational disease, has become a major public health problem in the world. Its causes are well known, but the pathogenesis of it is not completely clear and effective therapies are not currently available. Epigenetic modifications have been considered an initial event in the development of pneumoconiosis. Epigenetic regulatory mechanisms in pneumoconiosis include DNA methylation, non-coding RNA (ncRNA) , and histone modification. In recent years, many researchers have studied the effect of dust-induced pulmonary fibrosis-related gene expression at the epigenetic level on macrophage activation, lung fibroblast proliferation, activation, transdifferentiation, and epithelial or endothelial-mesenchymal transition (EMT/EndMT) to further elucidate the pathogenesis of pneumoconiosis. In this review, we discusses the epigenetic modifications in pneumoconiosis, with an aim to provide new insights into the early diagnosis, condition assessment and targeted therapy of this occupational disease. 10.3760/cma.j.issn.1001-9391.2019.04.019
Pulmonary dust foci as rat pneumoconiosis lesion induced by titanium dioxide nanoparticles in 13-week inhalation study. Particle and fibre toxicology BACKGROUND:Most toxicological studies on titanium dioxide (TiO) particles to date have concentrated on carcinogenicity and acute toxicity, with few studies focusing of pneumoconiosis, which is a variety of airspace and interstitial lung diseases caused by particle-laden macrophages. The present study examined rat pulmonary lesions associated with pneumoconiosis after inhalation exposure to TiO nanoparticles (NPs). METHODS:Male and female F344 rats were exposed to 6.3, 12.5, 25, or 50 mg/m anatase type TiO NPs for 6 h/day, 5 days/week for 13 weeks using a whole-body inhalation exposure system. After the last exposure the rats were euthanized and blood, bronchoalveolar lavage fluid, and all tissues including lungs and mediastinal lymph nodes were collected and subjected to biological and histopathological analyses. RESULTS:Numerous milky white spots were present in the lungs after exposure to 25 and 50 mg/m TiO NPs. Histopathological analysis revealed that the spots were alveolar lesions, characterized predominantly by the agglomeration of particle-laden macrophages and the presence of reactive alveolar epithelial type 2 cell (AEC2) hyperplasia. We defined this characteristic lesion as pulmonary dust foci (PDF). The PDF is an inflammatory niche, with decreased vascular endothelial cells in the interstitium, and proliferating AEC2 transformed into alveolar epithelial progenitor cells. In the present study, the AEC2 in the PDF had acquired DNA damage. Based on PDF induction, the lowest observed adverse effect concentration for pulmonary disorders in male and female rats was 12.5 mg/m and 6.3 mg/m, respectively. The no observed adverse effect concentration for male rats was 6.3 mg/m. There was a sex difference in lung lesion development, with females showing more pronounced lesion parameters than males. CONCLUSIONS:Inhalation exposure to TiO NPs caused PDF, an air-space lesion which is an alveolar inflammatory niche containing particle-laden macrophages and proliferating AEC2. These PDFs histopathologically resemble some pneumoconiosis lesions (pulmonary siderosis and hard metal pneumoconiosis) in workers and lung disease in smokers, suggesting that PDFs caused by exposure to TiO NPs in rats are an early pneumoconiosis lesion and may be a common alveolar reaction in mammals. 10.1186/s12989-022-00498-3
The phagocytosis and toxicity of amorphous silica. Costantini Lindsey M,Gilberti Renée M,Knecht David A PloS one BACKGROUND:Inhalation of crystalline silica is known to cause an inflammatory reaction and chronic exposure leads to lung fibrosis and can progress into the disease, silicosis. Cultured macrophages bind crystalline silica particles, phagocytose them, and rapidly undergo apoptotic and necrotic death. The mechanism by which particles are bound and internalized and the reason particles are toxic is unclear. Amorphous silica has been considered to be a less toxic form, but this view is controversial. We compared the uptake and toxicity of amorphous silica to crystalline silica. METHODOLOGY/PRINCIPAL FINDINGS:Amorphous silica particles are phagocytosed by macrophage cells and a single internalized particle is capable of killing a cell. Fluorescent dextran is released from endo-lysosomes within two hours after silica treatment and Caspase-3 activation occurs within 4 hours. Interestingly, toxicity is specific to macrophage cell lines. Other cell types are resistant to silica particle toxicity even though they internalize the particles. The large and uniform size of the spherical, amorphous silica particles allowed us to monitor them during the uptake process. In mCherry-actin transfected macrophages, actin rings began to form 1-3 minutes after silica binding and the actin coat disassembled rapidly following particle internalization. Pre-loading cells with fluorescent dextran allowed us to visualize the fusion of phagosomes with endosomes during internalization. These markers provided two new ways to visualize and quantify particle internalization. At 37 °C the rate of amorphous silica internalization was very rapid regardless of particle coating. However, at room temperature, opsonized silica is internalized much faster than non-opsonized silica. CONCLUSIONS/SIGNIFICANCE:Our results indicate that amorphous and crystalline silica are both phagocytosed and both toxic to mouse alveolar macrophage (MH-S) cells. The pathway leading to apoptosis appears to be similar in both cases. However, the result suggests a mechanistic difference between FcγRIIA receptor-mediated and non-opsonized silica particle phagocytosis. 10.1371/journal.pone.0014647
Silica-induced initiation of circular ZC3H4 RNA/ZC3H4 pathway promotes the pulmonary macrophage activation. Yang Xiyue,Wang Jing,Zhou Zewei,Jiang Rong,Huang Jie,Chen Lulu,Cao Zhouli,Chu Han,Han Bing,Cheng Yusi,Chao Jie FASEB journal : official publication of the Federation of American Societies for Experimental Biology Phagocytosis of silicon dioxide (SiO) into lung cells causes an inflammatory cascade that results in fibroblast proliferation and migration, followed by fibrosis. Circular RNAs (circRNAs) are a subclass of noncoding RNAs that are present within mammalian cells; however, researchers have not determined whether circRNAs are involved in the pathophysiologic process of silicosis. To elucidate the role of these RNAs in SiO-induced inflammation in pulmonary macrophages, we investigated the upstream molecular mechanisms and functional effects of circRNAs on cell apoptosis, proliferation, and migration. Primary cultures of alveolar macrophages from healthy donors and from patients and the RAW264.7 macrophage cell line were used to explore the functions of circZC3H4 RNA in macrophage activation. The experimental results indicated the following: 1) SiO concomitantly increased circZC3H4 RNA expression and increased ZC3H4 protein levels; 2) circular ZC3H4 (circZC3H4) RNA and ZC3H4 protein participated in SiO-induced macrophage activation; and 3) SiO-activated macrophages promoted fibroblast proliferation and migration via the circZC3H4 RNA/ZC3H4 pathway. The up-regulation of the ZC3H4 protein was confirmed in tissue samples from patients with silicosis. Our study elucidates a link between SiO-induced macrophage activation and the circZC3H4 RNA/ZC3H4 pathway, thereby providing novel insight into the potential use of ZC3H4 to develop novel therapeutic strategies for silicosis.-Yang, X., Wang, J., Zhou, Z., Jiang, R., Huang, J., Chen, L., Cao, Z., Chu, H., Han, B., Cheng, Y., Chao, J. Silica-induced initiation of circular ZC3H4 RNA/ZC3H4 pathway promotes the pulmonary macrophage activation. 10.1096/fj.201701118R
A Promising transwell co-culture cell model for silicosis. Toxicology in vitro : an international journal published in association with BIBRA Silicosis, one of the most ancient occupational diseases, has not been elucidated and addressed until now. Although some medicines were partly effective in the clinical treatment and certain plausible mechanisms were partially ascertained, it is still urgent and necessary to explore its real and specific pathogenesis. With the development of the cell co-culture technique, the transwell co-culture system has been applied in several scientific fields, which is able to simulate the pathogenic process in vivo to the largest extent. In this sense, a transwell co-culture cell model for silicosis including RFL-6 (lung fibroblasts of rats), RLE-6TN (type II alveolar epithelial cells of rats) and NR8383 (alveolar macrophages of rats) cells was successfully established and the developmental process of silicosis in this model could be roughly divided into three stages: inflammatory stage, progressive stage and fibrotic stage, as evidenced by the morphological features and the inflammatory cytokines and fibrotic proteins of supernatants and the cells in this system. Results of this project will pave the way for clarifying the mechanism of silicosis and building a practical platform for the further exploration of molecular initiating event (MIE) and adverse outcome pathway (AOP) of silicosis. 10.1016/j.tiv.2022.105318
Role of oxidants in interstitial lung diseases: pneumoconioses, constrictive bronchiolitis, and chronic tropical pulmonary eosinophilia. Rom William N Mediators of inflammation Oxidants such as superoxide anion, hydrogen peroxide, and myeloperoxidase from activated inflammatory cells in the lower respiratory tract contribute to inflammation and injury. Etiologic agents include inorganic particulates such as asbestos, silica, or coal mine dust or mixtures of inorganic dust and combustion materials found in World Trade Center dust and smoke. These etiologic agents are phagocytosed by alveolar macrophages or bronchial epithelial cells and release chemotactic factors that recruit inflammatory cells to the lung. Chemotactic factors attract and activate neutrophils, eosinophils, mast cells, and lymphocytes and further activate macrophages to release more oxidants. Inorganic dusts target alveolar macrophages, World Trade Center dust targets bronchial epithelial cells, and eosinophils characterize tropical pulmonary eosinophilia (TPE) caused by filarial organisms. The technique of bronchoalveolar lavage in humans has recovered alveolar macrophages (AMs) in dust diseases and eosinophils in TPE that release increased amounts of oxidants in vitro. Interestingly, TPE has massively increased eosinophils in the acute form and after treatment can still have ongoing eosinophilic inflammation. A course of prednisone for one week can reduce the oxidant burden and attendant inflammation and may be a strategy to prevent chronic TPE and interstitial lung disease. 10.1155/2011/407657
Dasatinib Reduces Lung Inflammation and Fibrosis in Acute Experimental Silicosis. Cruz Fernanda Ferreira,Horta Lucas Felipe Bastos,Maia Lígia de Albuquerque,Lopes-Pacheco Miquéias,da Silva André Benedito,Morales Marcelo Marco,Gonçalves-de-Albuquerque Cassiano Felippe,Takiya Christina Maeda,de Castro-Faria-Neto Hugo Caire,Rocco Patricia Rieken Macedo PloS one Silicosis is an occupational lung disease with no effective treatment. We hypothesized that dasatinib, a tyrosine kinase inhibitor, might exhibit therapeutic efficacy in silica-induced pulmonary fibrosis. Silicosis was induced in C57BL/6 mice by a single intratracheal administration of silica particles, whereas the control group received saline. After 14 days, when the disease was already established, animals were randomly assigned to receive DMSO or dasatinib (1 mg/kg) by oral gavage, twice daily, for 14 days. On day 28, lung morphofunction, inflammation, and remodeling were investigated. RAW 264.7 cells (a macrophage cell line) were incubated with silica particles, followed by treatment or not with dasatinib, and evaluated for macrophage polarization. On day 28, dasatinib improved lung mechanics, increased M2 macrophage counts in lung parenchyma and granuloma, and was associated with reduction of fraction area of granuloma, fraction area of collapsed alveoli, protein levels of tumor necrosis factor-α, interleukin-1β, transforming growth factor-β, and reduced neutrophils, M1 macrophages, and collagen fiber content in lung tissue and granuloma in silicotic animals. Additionally, dasatinib reduced expression of iNOS and increased expression of arginase and metalloproteinase-9 in silicotic macrophages. Dasatinib was effective at inducing macrophage polarization toward the M2 phenotype and reducing lung inflammation and fibrosis, thus improving lung mechanics in a murine model of acute silicosis. 10.1371/journal.pone.0147005
Abnormal secretion of interleukin-1 and tumor necrosis factor alpha by alveolar macrophages in coal worker's pneumoconiosis: comparison between simple pneumoconiosis and progressive massive fibrosis. Lassalle P,Gosset P,Aerts C,Fournier E,Lafitte J J,Degreef J M,Wallaert B,Tonnel A B,Voisin C Experimental lung research The aim of this study was to compare the secretion of tumor necrosis factor alpha (TNF alpha) and interleukin-1 (IL-1) by alveolar macrophages (AMs) harvested from patients with coal worker's pneumoconiosis (CWP) and control subjects. We observed higher levels of spontaneous TNF alpha and IL-1 secretion by AMs from patients with CWP than in those from healthy controls. We did not find any significant difference between the two groups in the incidence of simple pneumoconiosis and progressive massive fibrosis. In the group of coal miners without radiologic signs of pneumoconiosis, we found high levels of both cytokines in a subgroup of subjects still exposed to the mineral dust but not in the subgroup of subjects removed from exposure. These results indicate that AMs are involved in chronic lung inflammatory reactions to mineral dusts, partly by way of cytokine secretion. Moreover, cytokine secretion by AMs appears to be an early event that is detectable at the moment of mineral dust exposure. The results open new perspectives in the study of the mechanisms leading to CWP. 10.3109/01902149009064700
Dysregulation of the immune system caused by silica and asbestos. Maeda Megumi,Nishimura Yasumitsu,Kumagai Naoko,Hayashi Hiroaki,Hatayama Tamayo,Katoh Minako,Miyahara Naomi,Yamamoto Shoko,Hirastuka Junichi,Otsuki Takemi Journal of immunotoxicology Silica and asbestos cause pneumoconioses known as silicosis and asbestosis, respectively, that are each characterized by progressive pulmonary fibrosis. While local effects of inhaled silica particles alter the function of alveolar macrophages and sequential cellular and molecular biological events, general systemic immunological effects may also evolve. One well-known health outcome associated with silica exposure/silicosis is an increase in the incidence of autoimmune disorders. In addition, while exposure to silica--in the crystalline form--has also been seen to be associated with the development of lung cancers, it remains unclear as to whether or not silicosis is a necessary condition for the elevation of silica-associated lung cancer risks. Since asbestos is a mineral silicate, it would be expected to also possess generalized immunotoxicological effects similar to those associated with silica particles. However, asbestos-exposed patients are far better known than silicotic patients for development of malignant diseases such as lung cancer and mesothelioma, and less so for the development of autoimmune disorders. With both asbestos and crystalline silica, one important dysregulatory outcome that needs to be considered is an alteration in tumor immunity that allows for silica- or asbestos- (or asbestos-associated agent)-induced tumors to survive and thrive in situ. In this review, the immunotoxicological effects of both silica and asbestos are presented and contrasted in terms of their abilities to induce immune system dysregulation that then are manifest by the onset of autoimmunity or by alterations in host-tumor immunity. 10.3109/1547691X.2010.512579
Epithelial and extracellular matrix injury in quartz-inflamed lung: role of the alveolar macrophage. Donaldson K,Brown G M,Brown D M,Slight J,Li X Y Environmental health perspectives The bronchoalveolar leukocytes from quartz-inflamed lung were separated into macrophage-enriched and neutrophil-enriched populations on density gradients. Neutrophil-enriched populations showed the greatest activity in causing injury to epithelial cells and fibronectin in vitro. Inflammatory macrophage-enriched populations from quartz-exposed lung had the ability to cause fibronectin degradation but could not cause detachment injury to epithelial cells over and above that caused by control alveolar macrophages. Fibronectin damage in vivo could be an important factor in disordering the connective tissue scaffold of the lung, thereby favoring fibrosis. In vitro quartz stimulated more production of cytokines by alveolar macrophages than the inert particulate titanium dioxide. Cytokines could be important in upregulating adhesion molecules in the membranes of lung cells in vivo; this process could aid leukocyte/lung cell contact, allowing epithelial injury to be expressed, and could also be a factor leading to pathological change. 10.1289/ehp.9297221
Deposition and translocation of inhaled silica in rats. Quantification of particle distribution, macrophage participation, and function. Brody A R,Roe M W,Evans J N,Davis G S Laboratory investigation; a journal of technical methods and pathology Chronic exposure to silica dust causes fibrotic lung disease. Using brief exposures, we have attempted to define the initial patterns of dust deposition, anatomical compartments through which silica is translocated, and the participation of pulmonary macrophages in clearing the inhaled dust. To accomplish this, particle distribution and translocation at the alveolar level were studied in rats exposed to aerosolized alpha-quartz. Animals were exposed to 109 mg. per cu. m. of crystalline silica in inhalation chambers for 3 hours and sacrificed at varying times after exposure. The lungs were fixed by vascular perfusion through the right ventricle and tissue blocks were prepared for transmission and scanning electron microscopy. Lungs of additional animals were lavaged to recover populations of pulmonary macrophages for in vitro studies. Scanning electron microscopy in concert with back-scattered electron imaging showed that 24 hours postexposure there was a significant decrease in the number of silica particles per unit area of alveolar duct surface when compared with lung tissue from animals sacrificed immediately after exposure. Transmission electron microscopy revealed that silica crystals had been translocated to alveolar type I cells, interstitium, and macrophages. The percentage of silica-containing macrophages on alveolar surfaces increased from 36 +/- 2 per cent (mean +/- S.E.) immediately after exposure to 66 +/- 2 per cent during the 24 hours following exposure. This high percentage of macrophage participation was maintained through a 24-day postexposure period and then returned to 25 +/- 2 per cent 42 days after exposure. The percentage of silica-containing macrophages recovered by lavage were remarkably similar to those studied in situ: 24 +/- 4 per cent immediately postexposure, 62 +/- 3 per cent from 12 hours through 24 days, and 28 +/- 4 per cent 42 days postexposure. Although the percentage of macrophages with silica remained steady, the amount of silica per cell decreased during this 12-hour to 24-day period. Metabolic and viability studies of lavaged macrophages in vitro showed no differences between sham and silica-exposed animals. We propose that the events reported here represent normal, steady state clearance of a subpathogenic dose of potentially toxic particulates.
Wnt5a/Ca signaling regulates silica-induced ferroptosis in mouse macrophages by altering ER stress-mediated redox balance. Toxicology Silicosis is a chronic pulmonary disease characterized by diffuse fibrosis of lung caused by the deposition of silica dust (SiO). The inhaled silica-induced oxidative stress, ROS production and macrophage ferroptosis are key drivers of the pathological process of silicosis. However, mechanisms that involved in the silica-induced macrophage ferroptosis and its contributions to pathogenesis of silicosis remain elusive. In the present study, we showed that silica induced murine macrophage ferroptosis, accompanied by elevation of inflammatory responses, Wnt5a/Ca signaling activation, and concurrent increase of endoplasmic reticulum (ER) stress and mitochondrial redox imbalance in vitro and vivo. Mechanistic study further demonstrated that Wnt5a/Ca signaling played a key role in silica-induced macrophage ferroptosis by modulating ER stress and mitochondrial redox balance. The presence of Wnt5a/Ca signaling ligand Wnt5a protein increased the silica-induced macrophage ferroptosis by activating ER-mediated immunoglobulin heavy chain binding protein (Bip)-C/EBP homology protein (Chop) signaling cascade, reducing the expression of negative regulators of ferroptosis, glutathione peroxidase 4 (Gpx4) and solute carrier family 7 member 11 (Slc7a11), subsequentially increasing lipid peroxidation. The pharmacologic inhibition of Wnt5a signaling or block of calcium flow exhibited an opposite effect to Wnt5a, resulted in the reduction of ferroptosis and the expression of Bip-Chop signaling molecules. These findings were further corroborated by the addition of ferroptosis activator Erastin or inhibitor ferrostatin-1. These results provide a mechanism by which silica activates Wnt5a/Ca signaling and ER stress, sequentially leads to redox imbalance and ferroptosis in mouse macrophage cells. 10.1016/j.tox.2023.153514
Inhibition of alveolar macrophage spreading and phagocytosis by cotton bract tannin. A potential mechanism in the pathogenesis of byssinosis. Kreofsky T J,Russell J A,Rohrbach M S The American journal of pathology One of the major host-defense functions of alveolar macrophages is the phagocytosis and clearance of inhaled particles deposited in the lower airways and alveolar spaces. Recent studies have indicated that the condensed tannins present in cotton mill dust stimulate the secretion of neutrophil chemotactic factor and arachidonic acid from resident rabbit alveolar macrophages and that these responses may contribute to the acute pulmonary inflammatory reaction associated with byssinosis. To characterize further the effect of tannin on macrophage function, the ability of tannin to modulate alveolar macrophage spreading and phagocytosis in vitro was examined. Tannin caused a dose-dependent inhibition of alveolar macrophage spreading with nearly complete inhibition occurring at concentrations of 12.5 micrograms/ml. This inhibitory effect of tannin was not reversed with removal of tannin. Furthermore addition of tannin to previously spread macrophages actively caused the macrophages to round up. Examination of the structure of alveolar macrophages exposed to tannin by scanning and transmission electron microscopy revealed blebs on the surface of the cells and the loss of most of the cellular organelle structure, as compared to control macrophages. Tannin also modulated the ability of the alveolar macrophages to phagocytize unopsonized latex microspheres. The effect of tannin was biphasic. At the lowest concentration examined (3 micrograms/ml), tannin significantly enhanced phagocytosis of the latex microspheres. However, as the concentration was increased, phagocytosis decreased almost exponentially until at 50 micrograms/ml phagocytosis was significantly inhibited compared to control macrophages. These data indicate that tannin present in inhaled cotton mill dust could significantly decrease the ability of resident alveolar macrophages to phagocytize and thereby clear inhaled dust particles. This inhibitory effect would increase the time that particles remain exposed in the lower airway and alveolar spaces and thereby increase the time that potentially toxic compounds in the dust have to exert their biologic effect. This inhibition of macrophage function may therefore contribute to the pathogenesis of byssinosis.
Silica-induced inflammasome activation in macrophages: role of ATP and P2X7 receptor. Luna-Gomes Tatiana,Santana Patricia Teixeira,Coutinho-Silva Robson Immunobiology Silicosis is a fibrotic lung disease caused by the inhalation of silica particles, and is considered an occupational disease, given that these particles are present in the working environment of many mining and civil construction industries. NLRP3 inflammasome activation is an important mechanism during the inflammatory process of silicosis, and it promotes the production of cytokines, such as IL-1β and IL-18. ATP also plays an important role in silicosis. Specifically, extracellular ATP can activate P2X7 receptor, which then participates in the complete assembly of the NLRP3 inflammasome and its activation. Herein, we analyze the literature to provide a better understanding of the mechanisms underlying inflammasome activation and the role of P2X7 receptors in macrophages during silicosis. 10.1016/j.imbio.2015.05.004
Silica particles disorganize the polarization of pulmonary macrophages in mice. Zhao Youliang,Hao Changfu,Bao Lei,Wang Di,Li Yiping,Qu Yaqian,Ding Mingcui,Zhao Ahui,Yao Wu Ecotoxicology and environmental safety Silicosis is a fatal fibrotic lung disease caused by long-term silica particle exposure, in which pulmonary macrophages play an important role. However, the relationship between macrophage polarization and silicosis remains unclear. We established an experimental silicosis mouse model to investigate macrophage polarization during silicosis development. C57BL/c mice were exposed to silica by intra-tracheal instillation and sacrificed at different time points. Lung tissues and bronchoalveolar lavage fluid were collected for flow cytometry, quantitative reverse transcription polymerase chain reaction, enzyme-linked immunosorbent assays, western blotting, and histology examinations. The polarization of pulmonary macrophages was dysregulated during silicosis development. In the early stage of silicosis, M1 macrophages were induced and played a leading role in eliciting inflammatory; in the late stage, M2 macrophages were induced to promote tissue repair. Levels of several cytokines in lung tissue microenvironment changed with macrophage polarization. Inflammatory cytokines such as tumor necrosis factor-α and interleukin (IL)-1β and IL-6 were upregulated in the inflammation stage, while the anti-inflammatory cytokine IL-10 was upregulated in the fibrosis stage. Furthermore, we found that STAT (signal transducer and activator of transcription) and IRF (interferon regulatory factor) signaling pathway were involved in the regulation of macrophage polarization in silicosis. In summary, macrophage polarization is closely related to the occurrence and development of silicosis and may be a key point for further elucidating silicosis pathogenesis. 10.1016/j.ecoenv.2020.110364
Elucidation of alveolar macrophage cell response to coal dusts: Role of ferroptosis in pathogenesis of coal workers' pneumoconiosis. Sun Yingying,Kinsela Andrew S,Waite T David The Science of the total environment Causal factors underlying coal workers' pneumoconiosis (CWP) have been variously attributed to the presence of carbon, crystalline silica and reduced iron (Fe) minerals, especially pyrite and Fe/Si-amorphous compounds. The aim of this research was to assess the role of iron in CWP and, more specifically, the cytotoxicity of coal dusts with different elemental composition towards alveolar macrophages (AMs). Survival rate of AMs, alteration in the production of pro-inflammatory cytokine TNF-α, MDA (the lipid peroxidation product) and intracellular GSH were assessed using commercial assay kits. The quantitative interaction between iron and GSH was investigated by developing a numerical model. The presence of various reduced Fe minerals (viz. pyrite and siderite) in coal dusts exhibited a consistently acute adverse impact on the viability of AMs and enhanced the production of TNF-α. The presence of the clinically available Fe chelator deferiprone (DFP) and the cytosolic antioxidant glutathione (GSH) significantly increased the viability of AMs exposed to Fe bearing coal dusts, suggesting coal dusts containing reduced Fe minerals were likely contributors to the initial stages of AM cytotoxicity via a ferroptosis related pathway. Chemical kinetic modeling indicated that these results may be attributed to an enhanced consumption of GSH as a result of Fe redox cycling. FeGSH and GS produced from the interaction between ferric Fe and GSH facilitated the production of O which further oxidized GSH via a direct reaction between GSH and GS or GSO. These results suggest that coal dusts containing reduced Fe minerals and Fe compounds may elevate acute inflammation levels in AMs, indicating that crystalline silica may not be the only hazard of concern in mining environments. 10.1016/j.scitotenv.2022.153727
TNFR1/phox interaction and TNFR1 mitochondrial translocation Thwart silica-induced pulmonary fibrosis. Fazzi Fabrizio,Njah Joel,Di Giuseppe Michelangelo,Winnica Daniel E,Go Kristina,Sala Ernest,St Croix Claudette M,Watkins Simon C,Tyurin Vladimir A,Phinney Donald G,Fattman Cheryl L,Leikauf George D,Kagan Valerian E,Ortiz Luis A Journal of immunology (Baltimore, Md. : 1950) Macrophages play a fundamental role in innate immunity and the pathogenesis of silicosis. Phagocytosis of silica particles is associated with the generation of reactive oxygen species (ROS), secretion of cytokines, such as TNF, and cell death that contribute to silica-induced lung disease. In macrophages, ROS production is executed primarily by activation of the NADPH oxidase (Phox) and by generation of mitochondrial ROS (mtROS); however, the relative contribution is unclear, and the effects on macrophage function and fate are unknown. In this study, we used primary human and mouse macrophages (C57BL/6, BALB/c, and p47(phox-/-)) and macrophage cell lines (RAW 264.7 and IC21) to investigate the contribution of Phox and mtROS to silica-induced lung injury. We demonstrate that reduced p47(phox) expression in IC21 macrophages is linked to enhanced mtROS generation, cardiolipin oxidation, and accumulation of cardiolipin hydrolysis products, culminating in cell death. mtROS production is also observed in p47(phox-/-) macrophages, and p47(phox-/-) mice exhibit increased inflammation and fibrosis in the lung following silica exposure. Silica induces interaction between TNFR1 and Phox in RAW 264.7 macrophages. Moreover, TNFR1 expression in mitochondria decreased mtROS production and increased RAW 264.7 macrophage survival to silica. These results identify TNFR1/Phox interaction as a key event in the pathogenesis of silicosis that prevents mtROS formation and reduces macrophage apoptosis. 10.4049/jimmunol.1103516
Metabolic Adaptation of Macrophages as Mechanism of Defense against Crystalline Silica. Marrocco Antonella,Frawley Krystin,Pearce Linda L,Peterson James,O'Brien James P,Mullett Steven J,Wendell Stacy G,St Croix Claudette M,Mischler Steven E,Ortiz Luis A Journal of immunology (Baltimore, Md. : 1950) Silicosis is a lethal pneumoconiosis for which no therapy is available. Silicosis is a global threat, and more than 2.2 million people per year are exposed to silica in the United States. The initial response to silica is mediated by innate immunity. Phagocytosis of silica particles by macrophages is followed by recruitment of mitochondria to phagosomes, generation of mitochondrial reactive oxygen species, and cytokine (IL-1β, TNF-α, IFN-β) release. In contrast with LPS, the metabolic remodeling of silica-exposed macrophages is unclear. This study contrasts mitochondrial and metabolic alterations induced by LPS and silica on macrophages and correlates them with macrophage viability and cytokine production, which are central to the pathogenesis of silicosis. Using high-resolution respirometer and liquid chromatography-high-resolution mass spectrometry, we determined the effects of silica and LPS on mitochondrial respiration and determined changes in central carbon metabolism of murine macrophage cell lines RAW 264.7 and IC-21. We show that silica induces metabolic reprogramming of macrophages. Silica, as well as LPS, enhances glucose uptake and increases aerobic glycolysis in macrophages. In contrast with LPS, silica affects mitochondria respiration, reducing complex I and enhancing complex II activity, to sustain cell viability. These mitochondrial alterations are associated in silica, but not in LPS-exposed macrophages, with reductions of tricarboxylic acid cycle intermediates, including succinate, itaconate, glutamate, and glutamine. Furthermore, in contrast with LPS, these silica-induced metabolic adaptations do not correlate with IL-1β or TNF-α production, but with the suppressed release of IFN-β. Our data highlight the importance of complex II activity and tricarboxylic acid cycle remodeling to macrophage survival and cytokine-mediated inflammation in silicosis. 10.4049/jimmunol.2000628
Giant-cell interstitial pneumonia and hard-metal pneumoconiosis. A clinicopathologic study of four cases and review of the literature. Ohori N P,Sciurba F C,Owens G R,Hodgson M J,Yousem S A The American journal of surgical pathology We report four cases of giant-cell interstitial pneumonia that occurred in association with exposure to hard metals. All patients presented with chronic interstitial lung disease and had open-lung biopsies that revealed marked interstitial fibrosis, cellular interstitial infiltrates, and prominent intraalveolar macrophages as well as giant cells displaying cellular cannibalism. We also review the literature to determine the sensitivity and specificity of giant-cell interstitial pneumonia for hard-metal pneumoconiosis. Although hard-metal pneumoconiosis may take the form of usual interstitial pneumonia, desquamative interstitial pneumonia, and giant-cell interstitial pneumonia, the finding of giant-cell interstitial pneumonia is almost pathognomonic of hard-metal disease and should provoke an investigation of occupational exposure.
Role of nitric oxide in the progression of pneumoconiosis. Castranova V Biochemistry. Biokhimiia Conflicting evidence has been reported as to whether nitric oxide (NO) possesses anti-inflammatory or inflammatory properties. Data are presented indicating that in vitro or in vivo exposure to selected occupational dusts, i.e., crystalline silica, organic dust contaminated with endotoxin, or asbestos, results in upregulation of inducible nitric oxide synthase (iNOS) and the production of NO by alveolar macrophages and pulmonary epithelial cells. Nitric oxide production is associated temporally and anatomically with pulmonary damage, inflammation, and disease progression in response to occupational dusts. Blockage of inducible nitric oxide synthase by administration of NOS inhibitors or in iNOS knockout mice decreases the magnitude of injury and inflammation following in vivo exposure to silica, endotoxin, or asbestos. Therefore, NO may play an important role in the initiation and progression of pneumoconiosis.
Macrophage damage in relation to the pathogenesis of lung diseases. Brain J D Environmental health perspectives Pulmonary macrophages are important since their migratory patterns and behavior are often pivotal events in the pathogenesis of pulmonary disease. Alveolar macrophages act to decrease the probability of particle penetration through epithelial barriers, and their phagocytic and lytic potentials provide most of the known bactericadal properties of the lung. Macrophages are also involved in immune responses and in defense against neoplasms. Increased inert or infectious particles stimulate the recruitment of additional macrophages. Most free cells containing particles eventually reach the airways and are quickly carried to the pharynx and swallowed. In addition, evidence has now accumulated that macrophages play a part in the pathogenesis of pulmonary diseases. For example, the ingestion of some particles by macrophages causes a release of lysosomal enzymes into the macrophage cytoplasm. These enzymes may kill the macrophage, and dead or dying macrophages release a substance with attracts fibroblasts that elicit fibrogenic responses. Other toxic particles, such as cigarette smoke, my lead to a release of proteases and other toxic enzymes. All particles are capable of competitive inhibition of phagocytosis in macrophages and many may be cytotoxic and further depress phagocytosis. In addition, connective tissue macrophages may contribute to lung disease by concentrating and storing potent carcinogens or other toxic particles close to a reactive bronchial epithelium for long periods. Thus, even through macrophages serve as a first line of defense for the alveolar surface, they may also be capable of injuring the host while exercising their defensive role. 10.1289/ehp.803521
Health risk of chrysotile revisited. Critical reviews in toxicology This review provides a basis for substantiating both kinetically and pathologically the differences between chrysotile and amphibole asbestos. Chrysotile, which is rapidly attacked by the acid environment of the macrophage, falls apart in the lung into short fibers and particles, while the amphibole asbestos persist creating a response to the fibrous structure of this mineral. Inhalation toxicity studies of chrysotile at non-lung overload conditions demonstrate that the long (>20 µm) fibers are rapidly cleared from the lung, are not translocated to the pleural cavity and do not initiate fibrogenic response. In contrast, long amphibole asbestos fibers persist, are quickly (within 7 d) translocated to the pleural cavity and result in interstitial fibrosis and pleural inflammation. Quantitative reviews of epidemiological studies of mineral fibers have determined the potency of chrysotile and amphibole asbestos for causing lung cancer and mesothelioma in relation to fiber type and have also differentiated between these two minerals. These studies have been reviewed in light of the frequent use of amphibole asbestos. As with other respirable particulates, there is evidence that heavy and prolonged exposure to chrysotile can produce lung cancer. The importance of the present and other similar reviews is that the studies they report show that low exposures to chrysotile do not present a detectable risk to health. Since total dose over time decides the likelihood of disease occurrence and progression, they also suggest that the risk of an adverse outcome may be low with even high exposures experienced over a short duration. 10.3109/10408444.2012.756454
TNF-α-TNFR signal pathway inhibits autophagy and promotes apoptosis of alveolar macrophages in coal worker's pneumoconiosis. Journal of cellular physiology OBJECTIVE:Exposure to coal dust causes the development of coal worker's pneumoconiosis (CWP), which is associated with accumulating macrophages in the lower respiratory tract. This study was performed to investigate the effect of tumor necrosis factor-α (TNF-α)-tumor necrosis factor receptor (TNFR) signal pathway on autophagy and apoptosis of alveolar macrophages (AMs) in CWP. METHODS:AMs from controls exposed to coal dust and CWP patients were collected, in which expressions of TNF-α and TNFR1 were determined. Autophagy was observed by transmission electron microscopy, and apoptosis by light microscope and using terminal deoxynucleotidyl transferase dUTP nick-end labeling staining. AMs in CWP patients were treated with TNF-α or anti-TNF-α antibody. Besides, expressions of autophagy marker proteins, apoptosis-related factors, FAS, caspase-8, and receptor-interacting serine-threonine-protein kinase 3 (RIPK3) were determined by western Blot. Activities of caspase-3 and caspase-8 were determined by a fluorescence kit. Flow cytometry was applied to measure the expression of TNFR1 on the surface of the AM. RESULTS:TNF-α expression and TNFR1 expression on the surface of AM, as well as autophagy and apoptotic index were significantly increased in AMs of CWP patients. In response to the treatment of TNF-α, TNF-α expression and TNFR1 expression on the surface of AM as well as LC3I expression were increased, autophagy was decreased, and LC3, LC3II, Beclin1 and B-cell lymphoma 2 expressions decreased, whereas FAS expression and activity and expression of caspase-3 and caspase-8 increased, and apoptotic index increased. Moreover, the situations were reversed with the treatment of anti-TNF-α antibody. CONCLUSION:TNF-α-TNFR signal pathway was involved in the occurrence and development of CWP by activating FAS-caspase-8 and thus inhibiting autophagy while promoting apoptosis of AM. 10.1002/jcp.27061
How silicosis and coal workers' pneumoconiosis develop--a cellular assessment. Lapp N L,Castranova V Occupational medicine (Philadelphia, Pa.) In vitro and in vivo animal studies, as well as human investigations, strongly support the role of macrophage products in the development and progression of silicosis and coal workers' pneumoconiosis. Such products include enzymes and reactive oxygen species which may cause lung damage; cytokines which recruit and/or activate polymorphonuclear leukocytes and thus result in further oxidant damage to the lung; and fibrogenic factors which induce fibroblast proliferation and collagen synthesis. This mechanistic understanding of pulmonary disease should assist in developing strategies for prevention and treatment.
Fibroblast RNA and macrophage proteins (including the fibrogenic factor) in experimental silicosis. Kulonen E,Aalto M,Aho S,Lehtinen P,Potila M Environmental health perspectives A hypothesis is presented for the action of silica-treated macrophages on protein synthesis in fibroblasts and also a method for the isolation of silica-attached materials in lung tissue. The increased protein synthesis in the fibroblasts is due, at least partly, to an increase in mRNA. Silica prevents the suppressing "macrophage effect" of macrophage-originated ribonuclease on fibroblasts. However, under certain conditions, collagen synthesis is stimulated by silica-treated macrophage preparations to such an extent that the effect cannot be explained by the inhibition of macrophage ribonuclease alone. We therefore postulate the existence of a fibrogenic factor, which is released by the macrophages. This factor has been demonstrated and can be purified from lung homogenate of SiO2-treated rats. 10.1289/ehp.8351119
Immunologic aspects of pneumoconiosis. Scheule R K,Holian A Experimental lung research This review summarizes recent research bearing on the role played by cells of the immune system in the development of pneumoconiosis. Findings related to the cellular and humoral immune responses to silica and asbestos are highlighted. Experimental results from humans and animal models are integrated into our current understandings of cellular and cytokine-mediated pathways leading to the generation of immune responses that may contribute to fibrogenesis and fibrosis. Potential mechanisms leading to the generation of an immune response by particulates are discussed, together with the indirect effects of particulates on fibroblasts by way of the cytokine network in the lung. Finally, suggestions are given for future research to help further elucidate the relationships between the cellular components of the immune system of the lung and the fibroblast that lead to fibrosis. 10.3109/01902149109062872
Role of macrophage-derived cytokines in coal workers' pneumoconiosis. Vanhee D,Gosset P,Wallaert B,Tonnel A B Annals of the New York Academy of Sciences 10.1111/j.1749-6632.1994.tb39800.x
The role of macrophage-derived TGF-β1 on SiO-induced pulmonary fibrosis: A review. Zhang Zhao-Qiang,Tian Hai-Tao,Liu Hu,Xie Ruining Toxicology and industrial health Silicosis is an occupational fibrotic lung disease caused by inhaling large amounts of crystalline silica dust. Transforming growth factor-β1 (TGF-β1), which is secreted from macrophages, has an important role in the development of this disease. Macrophages can recognize and capture silicon dust, undergo M2 polarization, synthesize TGF-β1 precursors, and secrete them out of the cell where they are activated. Activated TGF-β1 induces cells from different sources, transforming them into myofibroblasts through autocrine and paracrine mechanisms, ultimately causing silicosis. These processes involve complex molecular events, which are not yet fully understood. This systematic summary may further elucidate the location and development of pulmonary fibrosis in the formation of silicosis. In this review, we discussed the proposed cellular and molecular mechanisms of production, secretion, activation of TGF-β1, as well as the mechanisms through which TGF-β1 induces cells from three different sources into myofibroblasts during the pathogenesis of silicosis. This study furthers the medical understanding of the pathogenesis and theoretical basis for diagnosing silicosis, thereby promoting silicosis prevention and treatment. 10.1177/0748233721989896
Cytokine polymorphisms in silicosis and other pneumoconioses. Yucesoy Berran,Vallyathan Val,Landsittel Douglas P,Simeonova Petia,Luster Michael I Molecular and cellular biochemistry Silicosis and coal workers' pneumoconiosis are complex multifactorial lung diseases whose etiopathogenesis are not well defined. It is generally accepted that fibrotic lung disorders are mediated by macrophage-derived cytokines and growth factors. There is evidence showing a crucial role for tumor necrosis factor-a (TNF-alpha) and interleukin-1 (IL-1) in inflammation caused by silica dust and in the transition from simple to progressive massive fibrosis. In this review we discuss genetic polymorphisms responsible for regulating the production of these proinflammatory cytokines and their role in modifying silicosis severity.
MCPIP1 Regulates Alveolar Macrophage Apoptosis and Pulmonary Fibroblast Activation After in vitro Exposure to Silica. Wang Xingang,Zhang Yuxia,Zhang Wei,Liu Haijun,Zhou Zewei,Dai Xiaoniu,Cheng Yusi,Fang Shencun,Zhang Yingming,Yao Honghong,Chao Jie Toxicological sciences : an official journal of the Society of Toxicology BACKGROUND:Silicosis is a fatal and fibrotic pulmonary disease caused by the inhalation of silica. After arriving at the alveoli, silica is ingested by alveolar macrophages (AMOs), in which monocyte chemotactic protein-induced protein 1 (MCPIP1) plays an essential role in controlling macrophage-mediated inflammatory responses. However, the mechanism of action of MCPIP1 in silicosis is poorly understood. METHODS:Primary rat AMOs were isolated and treated with SiO2 (50 µg/cm(2)). MCPIP1 and AMO activation/apoptosis markers were detected by immunoblotting. MCPIP1 was down-regulated using siRNA in AMOs. The effects of AMOs on fibroblast activation and migration were evaluated using a gel contraction assay, a scratch assay, and a nested collagen matrix migration model. RESULTS:After exposure to SiO2, MCPIP1 was significantly increased in rat AMOs. Activation and apoptosis markers in AMOs were up-regulated after exposure to SiO2 Following siRNA-mediated silencing of MCPIP1 mRNA, the markers of AMO activation and apoptosis were significantly decreased. Rat pulmonary fibroblasts (PFBs) cultured in conditional medium from AMOs treated with MCPIP1 siRNA and SiO2 showed significantly less activation and migration compared with those cultured in conditional medium from AMOs treated with control siRNA and SiO2 CONCLUSION: Our data suggest a vital role for MCPIP1 in AMO apoptosis and PFB activation/migration induced by SiO2. 10.1093/toxsci/kfw029
Effects of abnormal expression of fusion and fission genes on the morphology and function of lung macrophage mitochondria in SiO-induced silicosis fibrosis in rats in vivo. Zhang Zhao-Qiang,Zhang Chun-Zhi,Shao Bo,Pang Dao-Hua,Han Gui-Zhi,Lin Li Toxicology letters Silicosis is a serious occupational disease affecting millions of related workers. Many studies showed lung macrophages play an important role in the disease. However, the changes of macrophages are not fully characterized and the mechanisms need further investigations. The objectives of this work were to evaluate the effects of abnormal expression of fusion and fission genes on the morphology and function of lung macrophage mitochondria in SiO-induced silicosis fibrosis in rats. In this study, the rats were injected with 1 mL of SiO suspension (100 mg/mL) into the lungs to establish silicosis models, and killed after 30, 60, and 120 days. The rats which were injected with normal saline (1 mL) into lungs were used as control. The lungs of rats were taken for pathological observation. Lung macrophages were collected to measure the number, activity, level of MDA and SOD, and relative content of fusion (Mfn1, Mfn2) and fission (Fis, DRP) genes. Subsequently, mitochondria were extracted from the macrophages to measure the changes of function, including MDA, SOD, ATP, and ATPase. We found that silica dust inhalation led to the proliferation of collagen fibers in the lung tissue. During this process, the number and activity of macrophages increased, the degree of lipid peroxidation increased, and the expression of mitochondrial fusion and fission genes was abnormal. Moreover, the mitochondrial lipid peroxidation level in macrophages increased, the production of ATP and the activity of ATPase decreased, and the abnormal forms of mitochondria occurred. Our results indicated that the morphology and function of mitochondria in macrophages changed during the progress of silicosis, which were related to the abnormal expression of fusion and fission genes. 10.1016/j.toxlet.2019.04.029
Annexin A5 promotes macrophage activation and contributes to pulmonary fibrosis induced by silica particles. Luo C,Ji X,Fan J,Hou Z,Wang T,Wu B,Ni C Toxicology and industrial health OBJECTIVE:To investigate the contributions and underlying molecular mechanisms of annexin A5 toward silica-induced pulmonary fibrosis. METHODS:Male C57BL/6 mice were randomly divided into three groups and instilled intratracheally with silica, saline, or air. Mice were euthanized at 3, 7, 14, or 28 days following treatment. Annexin A5 levels in serum and lung tissues were detected by enzyme-linked immunosorbant assay (ELISA) assays or Western blots. The association of annexin A5 levels with silica-induced lung fibrosis was further investigated in the macrophage cell line, RAW264.7. Following exposure of these cells to silica at a concentration of 200 μg/ml for 6 or 12 h, the expression levels of transforming growth factor β1 (TGF-β1), interleukin 1α (IL-1α), Fas ligand (FasL), and their downstream targets were evaluated by Western blots. Furthermore, annexin A5 and FasL were knocked down by small interfering ribonucleic acid (siRNA) and TGF-β1 secretion into the cell culture medium was measured by ELISA assays or Western blots. RESULTS:Mice treated with silica demonstrated lung fibrosis at 28 days following exposure, whereas, in controls, only mild and transient inflammation was evident at day 3 and day 7 postinstillation and was not present at day 14. Furthermore, silica-exposed mice exhibited significantly (p < 0.05) elevated levels of annexin A5 in serum and lung tissues, relative to control groups. Consistent with these findings, silica exposure of RAW264.7 cells for 6 or 12 h, led to an annexin A5-dependent increase in the expression levels of TGF-β1, IL-1α, FasL, and their downstream target molecules. These silica-induced changes were reversed by siRNA-mediated knockdown of annexin A5, but downregulation of FasL led to increased annexin A5 expression and reduced levels of TGF-β1, IL-1α, and FasL downstream target molecules. CONCLUSIONS:These findings define a role of annexin A5 in promoting macrophage activation via Fas/FasL pathways in silica-induced lung fibrosis. 10.1177/0748233715572744
[Relationship between autoimmune diseases and pneumoconiosis]. Matsuoka Y,Tomita M,Yoshino I,Hosoda Y Sangyo igaku. Japanese journal of industrial health In recent years, with the aging of patients with pneumoconiosis, autoimmune diseases as a complication have been observed. One of the reasons for this may be that autoimmune diseases are prone to develop among the elderly. On the other hand, it has been reported that dust itself, such as silica for example, has adjuvant effect. A review of the recent literature published in Japan and abroad was made to clarify the relationship between pneumoconiosis and autoimmune diseases and the following results were obtained. 1) Disorders which accompany pneumoconiosis: Scleroderma, rheumatoid arthritis, systemic lupus erythematosus (SLE), and disorders of the kidney and liver have been reported. In Japan, about 30 cases of pneumoconiosis accompanied with autoimmune diseases have been reported. In many of the reports, patients with pneumoconiosis and scleroderma have a past history of exposure to silica. In both case studies and case control studies, patients with rheumatoid arthritis and history of silica exposure are prone to develop pneumoconiosis. 2) Immunological studies of patients with pneumoconiosis: As for humoral immunity, elevation of polyclonal gamma-globulin, especially IgG, has been often reported together with high positive rate of autoantibodies such as antinuclear antibodies. In cellular immunity, decreased delayed type skin reaction and decreased CD4/8 ratio have been reported. In human leukocyte antigen (HLA) typing the elevated frequency of DR4 has been reported. In the study of BAL increased production of superoxide anion O2- by alveolar macrophages has been observed. 3) EXPERIMENTAL STUDIES: Silica is well known for its toxicity to cells and also for its adjuvant effect. In the German Democratic Republic, patients with scleroderma and history of long term silica exposure are recognized as patients with occupational disease even though pneumoconiosis is not clearly demonstrated on X-ray film. It is difficult from this review to nrake a definite conclusion regarding the relation between silicosis and autoimmune diseases. There is a need to repeat this review of the literature on autoimmune diseases and pneumoconiosis in the near future. 10.1539/joh1959.34.421
Secretion and mRNA expression of TNF alpha and IL-6 in the lungs of pneumoconiosis patients. Vanhée D,Gosset P,Marquette C H,Wallaert B,Lafitte J J,Gosselin B,Voisin C,Tonnel A B American journal of respiratory and critical care medicine Exposure to coal-mine dust leads to coal workers' pneumoconiosis (CWP), characterized by the development of a perifocal and progressive fibrotic reaction. In order to confirm their in vivo participation in the pathogenesis of CWP, the expression of tumor necrosis factor (TNF) and interleukin-6 (IL-6) was evaluated in bronchoalveolar lavage (BAL) specimens collected from 12 patients with simple pneumoconiosis (SP) and six with progressive massive fibrosis (PMF), and in pulmonary tissue from one patient with SP and three with PMF. Expression of TNF and IL-6 was assessed using both in situ hybridization and immunohistochemistry. The number of positive cells found in BALF was significantly higher for patients with PMF (TNF = 55 +/- 6%; IL-6 = 46 +/- 12.8%) than for those with SP (TNF = 34 +/- 11.6%; IL-6 = 26 +/- 10.2%) or normal controls (TNF = 15 +/- 5.5%; IL-6 = 13.3 +/- 6%), and was correlated with cytokine concentrations in supernatants from alveolar macrophages (AM). In lung biopsies, the expression of messenger ribonucleic acid (mRNA) for TNF was associated with the presence of coal dust and was limited to lung macrophages; mRNA for IL-6 was detected in mononuclear phagocytes but also in other types of cells such as endothelial cells. Monokine synthesis was confirmed by immunohistochemistry. These data confirm that TNF and IL-6 production is increased in the lungs of pneumoconiotic patients. Moreover TNF and IL-6 expression was associated with the presence of coalmine dust particles, suggesting a direct role of mineral particles in the cytokine production and development of pneumoconiotic lesions in CWP. 10.1164/ajrccm.152.1.7599837
The pulmonary macrophage. Bowden D H Environmental health perspectives An overview of the pulmonary macrophage is provided, with particular emphasis on the origin of this cell and the adaptive mechanisms whereby the macrophagic system is able to respond to increased inhalant loads of organic and inorganic pollutants. Evidence is presented which favors an hematopoietic origin for the alveolar macrophage with a monocytic transportation compartment in the blood and an interstitial cell compartment in the lung in which cellular division and maturation may occur. Through the simple mechanism of increased cellular turnover this system of mononuclear phagocytes rapidly adapts to most inhalant challenges. In addition to its primary tasks phagocyte and destroyer of microorganisms the macrophage plays a pivotal role in the genesis of silicotic fibrosis, and it is possible that similar mechanisms may hold for a variety of cryptogenic fibroses. Paradoxically, destruction of collagen by the dual mechanisms of phagocytosis and the secretion of lytic enzymes may also occur. The relevance of this secretory function of the macrophage to the pathogenesis of destructive diseases of the lung such as emphysema remains to be determined. 10.1289/ehp.761655
[Macrophage apoptosis and the levels of interleukin-1 and interleukin-8 in the rats exposed to silica]. Jin Yu-Lan,Zhang Wen-Li,Yao San-Qiao,Fan Xue-Yun,Xu Ying-Jun,Bai Yu-Ping,Yuan Ju-Xiang Zhonghua lao dong wei sheng zhi ye bing za zhi = Zhonghua laodong weisheng zhiyebing zazhi = Chinese journal of industrial hygiene and occupational diseases OBJECTIVE:To study the roles of macrophage apoptosis, IL-1, and IL-8 in the pathogenesis of rat pulmonary fibrosis induced by silica. METHODS:Forty eight male Wistar rats were divided into the 4 control groups (24 rats) and 4 experimental groups (24 rats). Rats in the control groups were treated with 1 ml normal saline by trachea instillation, whereas the rats in experimental groups were exposed 1 ml silica suspension (100 mg/ml) by trachea instillation for 1, 7, 14 and 28 days, respectively. Six rats of each group were sacrificed, then the bronchoalveolar lavage fluid and lung tissues were collected, respectively. Pulmonary inflammation, fibrosis and other pathological changes were detected with H.E. staining. Morphological changes of the early stage apoptosis in macrophages were detected with transmission electron microscope (TEM). The early apoptosis rates of macrophages in BALF were also assessed using Annexin V-FITC/PI kit. The IL-1 and IL-8 levels of serum were measured with the ELISA. RESULTS:The apoptotic rates (11.48% +/- 0.24%, 16.03% +/- 0.68%, 15.53% +/- 1.07%, 18.92% +/- 2.70%, respectively) of macrophage in the experimental groups increased obviously with time, as compared to the controls (5.47% +/- 2.06%, 6.39% +/- 0.215, 9.07% +/- 0.61% and 8.54% +/- 0.16%, Respectively) (P < 0.05). The IL-1 levels of serum in the experimental groups were 23.64 +/- 0.84, 23.38 +/- 1.10, 22.21 +/- 0.86 and 24.29 +/- 1.31 pg/ml, respectively, which were significantly higher than those (18.52 +/- 1.23, 18.40 +/- 1.6, 17.92 +/- 2.21 and 18.53 +/- 2.64 pg/ml, respectively) in the control groups (P < 0.05) without time-effect relationship. The serum IL-8 levels on the 1st, 7th and 14th days in the experimental groups were 21.32 +/- 1.44, 21.90 +/- 2.08 and 22.00 +/- 2.80 pg/ml, respectively, which were significantly higher than those (17.69 +/- 1.09, 16.98 +/- 2.09 and 17.54 +/- 1.62 pg/ml, respectively) in the control groups (P < 0.05). CONCLUSION:The early macrophage apoptosis and changes of IL-1 and IL-8 may in lungs may play an important role in the development of pulmonary fibrosis induced by silica.
Crystalline silica-induced macrophage pyroptosis interacting with mitophagy contributes to pulmonary fibrosis via modulating mitochondria homeostasis. Journal of hazardous materials Environmental exposure to crystalline silica (CS) can lead to silicosis. Alveolar macrophages (AMs) play a crucial role in the pathogenesis of silicosis. Previously, we demonstrated that enhancing AMs mitophagy exerted protective effects on silicosis with a restrained inflammatory response. However, the exact molecular mechanisms are elusive. Pyroptosis and mitophagy are two different biological processes that determine cell fate. Exploring whether there were interactions or balances between these two processes in AMs would provide new insight into treating silicosis. Here we reported that crystalline silica induced pyroptosis in silicotic lungs and AMs with apparent mitochondria injury. Notably, we identified a reciprocal inhibitory effect between mitophagy and pyroptosis cascades in AMs. By enhancing or diminishing mitophagy, we demonstrated that PINK1-mediated mitophagy helped clear damaged mitochondria to negatively regulate CS-induced pyroptosis. While constraining pyroptosis cascades by NLRP3, Caspase1, and GSDMD inhibitors, respectively, displayed enhanced PINK1-dependent mitophagy with lessened CS-injured mitochondria. These observed effects were echoed in the mice with enhanced mitophagy. Therapeutically, we demonstrated abolishing GSDMD-dependent pyroptosis by disulfiram attenuated CS-induced silicosis. Collectively, our data demonstrated that macrophage pyroptosis interacting with mitophagy contributes to pulmonary fibrosis via modulating mitochondria homeostasis, which may provide potential therapeutic targets. 10.1016/j.jhazmat.2023.131562
Beryllium disease. Saltini C,Amicosante M The American journal of the medical sciences Berylliosis is an environmental chronic inflammatory disorder of the lung caused by inhalation of insoluble beryllium (Be) dusts and characterized by the accumulation of CD4+ T cells and macrophages in the lower respiratory tract. In response to Be inhalation, noncaseating granuloma formation and, eventually, fibrosis. The immunopathogenic process is maintained by Be-specific lung CD4+ T-lymphocytes. Consistent with the disease immunopathology, these Be-specific T cells have a T-helper 1 phenotype producing interleukin-2 and interferon-gamma, the macrophage-activating cytokine driving the granulomatous reaction. Previous studies have demonstrated that the glutamic acid in position 69 of the human leukocyte antigen class II b chain is strongly associated with increased susceptibility to Be in exposed workers, suggesting that human leukocyte antigen gene markers may be used as epidemiological probes to identify population groups at higher risk. 10.1097/00000441-200101000-00013
MicroRNA-205-5p targets E2F1 to promote autophagy and inhibit pulmonary fibrosis in silicosis through impairing SKP2-mediated Beclin1 ubiquitination. Qian Qingzeng,Ma Qinghua,Wang Bin,Qian Qingqiang,Zhao Changsong,Feng Fumin,Dong Xiaona Journal of cellular and molecular medicine Silicosis is an occupational disease characterized by extensive pulmonary fibrosis, and the underlying pathological process remains uncertain. Herein, we explored the molecular mechanism by which microRNA-205-5p (miR-205-5p) affects the autophagy of alveolar macrophages (AMs) and pulmonary fibrosis in mice with silicosis through the E2F transcription factor 1 (E2F1)/S-phase kinase-associated protein 2 (SKP2)/Beclin1 axis. Alveolar macrophages (MH-S cells) were exposed to crystalline silica (CS) to develop an in vitro model, and mice were treated with CS to establish an in vivo model. Decreased Beclin1 and increased SKP2 and E2F1 were identified in mice with silicosis. We silenced or overexpressed miR-205-5p, E2F1, SKP2 and Beclin1 to investigate their potential roles in pulmonary fibrosis in vivo and autophagy in vitro. Recombinant adenovirus mRFP-GFP-LC3 was transduced into the MH-S cells to assay autophagic flow. Knocking down Beclin1 promoted pulmonary fibrosis and suppressed the autophagy. Co-immunoprecipitation and ubiquitination assays suggested that SKP2 induced K48-linked ubiquitination of Beclin1. Furthermore, chromatin immunoprecipitation-PCR revealed the site where E2F1 bound to the SKP2 promoter between 1638 bp and 1645 bp. As shown by dual-luciferase reporter gene assay, the transfection with miR-205-5p mimic inhibited the luciferase activity of the wild-type E2F1 3'untranslated region, suggesting that miR-205-5p targeted E2F1. Additionally, miR-205-5p overexpression increased autophagy and reduced the pulmonary fibrosis, while overexpression of E2F1 or SKP2 or inhibition of Beclin1 could annul this effect. The current study elucidated that miR-205-5p targeted E2F1, thereby inhibiting SKP2-mediated Beclin1 ubiquitination to promote macrophage autophagy and inhibit pulmonary fibrosis in mice with silicosis. 10.1111/jcmm.16825
Cyclophilin A accelerates SiO-induced macrophage foaming. Cellular signalling Silicosis is a common occupational disease characterized by lung inflammation, fibrosis and pulmonary dysfunction caused by long-term inhalation of free SiO. Cell foaming and the change of CyPA have been observed in SiO-induced macrophages, but the specific mechanism of CyPA in SiO-induced foam cells remains poorly understood. The purpose of this study is to explore the mechanism of CyPA in SiO-induced macrophage foaming and its effect on silicosis. We found that overexpression of CyPA promoted the macrophage foaming and the expression of COL I and α-SMA, while silencing CyPA inhibites the macrophage foaming and the expression of COL I and α-SMA. After blocking the expression of CD36 on the basis of overexpression CyPA, we found it inhibites the macrophage foaming. In conclusion, CyPA can affect the foaming of macrophages and may participate in silicosis fibrosis. 10.1016/j.cellsig.2022.110562
Cytokines and cytokine network in silicosis and coal workers' pneumoconiosis. Vanhée D,Gosset P,Boitelle A,Wallaert B,Tonnel A B The European respiratory journal The alveolar macrophage (AM) is a critically important cell playing a prominent role in lung inflammation via the production of oxygen radicals, enzymes, arachidonic acid metabolites, and also a large panel of cytokines. Among interstitial lung disorders, silicosis and coal workers' pneumoconiosis (CWP) are the most widespread fibrotic lung diseases. Although their pathophysiology remains incompletely understood, several lines of evidence suggest the participation of cytokines produced by AMs at least in the initiation of the alveolitis. In vitro exposure of AMs (obtained from healthy subjects) to coal dust particles triggered a significant release of tumour necrosis factor (TNF) and interleukin-6, by comparison with titanium dioxide used as a biologically inert control dust. Moreover, it appeared that coal mine dust was more aggressive than similar concentrations of pure silica, suggesting that cytokine secretion induced by coal mine dust was not exclusively related to the presence of silica but resulted from a complex interaction between the different components. In silicosis and CWP, bronchoalveolar lavage showed a large influx of mononuclear phagocytes, with an increased spontaneous production of oxidants, fibronectin, neutrophil chemotactic factor, and also of interleukin-6 and TNF-alpha. This spontaneous cytokine release was associated with an increased cytokine messenger ribonucleic acid (mRNA) expression in the lungs of coal miners.(ABSTRACT TRUNCATED AT 250 WORDS)
Prevalence and pathogenesis of pneumoconiosis in coal workers. Heppleston A G Environmental health perspectives Dust dose and composition do not appear to account wholly for changes in the prevalence of coal workers' pneumoconiosis in Europe. In certain coal pits high progression evidently occurred with relatively low dust exposure or vice versa, whereas progression in relation to dust levels might be variable. Exceptionally high quartz concentrations occur in coal mine dust when pneumoconiosis may progress with unusual rapidity. Under such circumstances lesions resembling silicotic nodules may be found, but with the customarily lower levels of quartz the pathological features assume the form characteristic of coal workers. Morphological changes in relation to dust content of human and animal lungs, as well as cellular behavior, have not accounted completely for the epidemiological findings. Considering all the pathological evidence helps explain the pathogenesis of pneumoconiosis and vagaries of progression. The origin of progressive massive fibrosis cannot be explained simply in terms of dust burden or immunological features, and the role of an infective factor cannot be dismissed. Moreover, lipid secretion by alveolar epithelium introduces a new element that could affect the development of simple and complicated pneumoconiosis. In vitro, cytotoxicity appeared to be too variable for predictive purposes, though direct assay of fibrogenicity using the macrophage fibrogenic factor suggested that dust dose was more important than dust composition. Assessing individual susceptibility presents serious obstacles. 10.1289/ehp.8878159
Silicosis and coal workers' pneumoconiosis. Castranova V,Vallyathan V Environmental health perspectives Exposure to coal mine dust and/or crystalline silica results in pneumoconiosis with initiation and progression of pulmonary fibrosis. This review presents characteristics of simple and complicated coal workers' pneumoconiosis (CWP) as well as pathologic indices of acute and chronic silicosis by summarizing results of in vitro, animal, and human investigations. These results support four basic mechanisms in the etiology of CWP and silicosis: a) direct cytotoxicity of coal dust or silica, resulting in lung cell damage, release of lipases and proteases, and eventual lung scarring; b) activation of oxidant production by pulmonary phagocytes, which overwhelms the antioxidant defenses and leads to lipid peroxidation, protein nitrosation, cell injury, and lung scarring; c) activation of mediator release from alveolar macrophages and epithelial cells, which leads to recruitment of polymorphonuclear leukocytes and macrophages, resulting in the production of proinflammatory cytokines and reactive species and in further lung injury and scarring; d) secretion of growth factors from alveolar macrophages and epithelial cells, stimulating fibroblast proliferation and eventual scarring. Results of in vitro and animal studies provide a basis for proposing these mechanisms for the initiation and progression of pneumoconiosis. Data obtained from exposed workers lend support to these mechanisms. 10.1289/ehp.00108s4675
NOX4 modulates macrophage phenotype and mitochondrial biogenesis in asbestosis. He Chao,Larson-Casey Jennifer L,Davis Dana,Hanumanthu Vidya Sagar,Longhini Ana Leda F,Thannickal Victor J,Gu Linlin,Carter A Brent JCI insight Macrophage activation is implicated in the development of pulmonary fibrosis by generation of profibrotic molecules. Although NADPH oxidase 4 (NOX4) is known to contribute to pulmonary fibrosis, its effects on macrophage activation and mitochondrial redox signaling are unclear. Here, we show that NOX4 is crucial for lung macrophage profibrotic polarization and fibrotic repair after asbestos exposure. NOX4 was elevated in lung macrophages from subjects with asbestosis, and mice harboring a deletion of NOX4 in lung macrophages were protected from asbestos-induced fibrosis. NOX4 promoted lung macrophage profibrotic polarization and increased production of profibrotic molecules that induce collagen deposition. Mechanistically, NOX4 further augmented mitochondrial ROS production and induced mitochondrial biogenesis. Targeting redox signaling and mitochondrial biogenesis prevented the profibrotic polarization of lung macrophages by reducing the production of profibrotic molecules. These observations provide evidence that macrophage NOX4 is a potentially novel therapeutic target to halt the development of asbestos-induced pulmonary fibrosis. 10.1172/jci.insight.126551
Macrophage-derived exosomes mediate silica-induced pulmonary fibrosis by activating fibroblast in an endoplasmic reticulum stress-dependent manner. Journal of cellular and molecular medicine Macrophages play a key role in silicosis, and exosomes are potent mediators of intercellular communication. This suggests that macrophage-derived exosomes have a potential contribution to the pathogenesis of silicosis. To investigate whether macrophage-derived exosomes promote or inhibit lung fibrosis, in vitro, silica-exposed macrophage-derived exosomes (SiO -Exos) were collected and cocultured with fibroblasts. The expression of collagen I and α-SMA was evaluated. Furthermore, the endoplasmic reticulum (ER) stress markers BIP, XBP1s and P-eIF2α were assessed after treatment with or without the ER stress inhibitor 4-PBA. In vivo, mice were pre-treated with the exosome secretion inhibitor GW4869 prior to silica exposure. After sacrifice, lung tissues were histologically examined, and the expression of proinflammatory cytokines (TNF-α, IL-1β and IL-6) in bronchoalveolar lavage fluid (BALF) was measured. The results showed that the expression of collagen I and α-SMA was up-regulated after treatment with SiO -Exos, accompanied by increased expression of BIP, XBP1s and P-eIF2α. Pre-treatment with 4-PBA reversed this effect. More importantly, an in vivo study demonstrated that pre-treatment with GW4869 decreased lung fibrosis and the expression of TNF-α, IL-1β and IL-6 in BALF. These results suggested that SiO -Exos are profibrogenic and that the facilitating effect is dependent on ER stress. 10.1111/jcmm.16524
SPP1 derived from silica-exposed macrophage exosomes triggers fibroblast transdifferentiation. Huang Ruoxuan,Hao Changfu,Wang Di,Zhao Qiuyan,Li Chao,Wang Chen,Yao Wu Toxicology and applied pharmacology The occurrence and development of silicosis is related to the interaction of multiple cells through signal transmission caused by silica dust. Including inflammatory changes reduced by macrophages and phenotypic transdifferentiation reduced by lung fibroblasts. As a communication medium between cells, exosomes have become a hot research topic. To explore the role of exosomal proteins in the occurrence and development of silicosis and the possible intervention targets, this study conducted proteomic analysis of macrophage-derived exosomes induced by silica, to identify specific proteins for intervention. In this study, we used proteomic analysis to screen exosomal protein profiles from the RAW264.7 macrophages exposed to silica. A total of 291 proteins were differentially expressed, of which 178 were upregulated and 113 were downregulated. By performing functional annotation and analysis of the differentially expressed proteins, we identified proteins SPP1, HMGB3, and HNRNPAB, which were consistent with the proteomics analysis. The involvement of SPP1 protein in fibrosis was studied further. Knocking down the expression of SPP1 in exosomes resulted in a decrease in fibrosis-related indicators. These results help to understand that exosomal protein can mediate cell communication and play a key role in the transition from fibroblasts to myofibroblasts. Further, this study also provided strategies and scientific basis for future studies on the intervention of silicosis. 10.1016/j.taap.2021.115559
Glycolytic Reprogramming in Silica-Induced Lung Macrophages and Silicosis Reversed by Ac-SDKP Treatment. Mao Na,Yang Honghao,Yin Jie,Li Yaqian,Jin Fuyu,Li Tian,Yang Xinyu,Sun Ying,Liu Heliang,Xu Hong,Yang Fang International journal of molecular sciences Glycolytic reprogramming is an important metabolic feature in the development of pulmonary fibrosis. However, the specific mechanism of glycolysis in silicosis is still not clear. In this study, silicotic models and silica-induced macrophage were used to elucidate the mechanism of glycolysis induced by silica. Expression levels of the key enzymes in glycolysis and macrophage activation indicators were analyzed by Western blot, qRT-PCR, IHC, and IF analyses, and by using a lactate assay kit. We found that silica promotes the expression of the key glycolysis enzymes HK2, PKM2, LDHA, and macrophage activation factors iNOS, TNF-α, Arg-1, IL-10, and MCP1 in silicotic rats and silica-induced NR8383 macrophages. The enhancement of glycolysis and macrophage activation induced by silica was reduced by Ac-SDKP or siRNA- treatment. This study suggests that Ac-SDKP treatment can inhibit glycolytic reprogramming in silica-induced lung macrophages and silicosis. 10.3390/ijms221810063
circRNA Mediates Silica-Induced Macrophage Activation Via HECTD1/ZC3H12A-Dependent Ubiquitination. Theranostics Phagocytosis of silicon dioxide (SiO) into lung cells causes an inflammatory cascade that results in fibroblast proliferation and migration, followed by fibrosis. Circular RNAs (circRNAs) are a subclass of non-coding RNAs detected within mammalian cells; however, researchers have not determined whether circRNAs are involved in the pathophysiological process of silicosis. The upstream molecular mechanisms and functional effects on cell apoptosis, proliferation and migration were investigated to elucidate the role of circRNAs in SiO-induced inflammation in pulmonary macrophages. Primary cultures of alveolar macrophages from healthy donors and patients as well as the RAW264.7 macrophage cell line were used to explore the functions of circHECTD1 (HECT domain E3 ubiquitin protein ligase 1) in macrophage activation. The results of the experiments indicated that 1) SiO concomitantly decreased circHECTD1 levels and increased HECTD1 protein expression; 2) circHECTD1 and HECTD1 were involved in SiO-induced macrophage activation via ubiquitination; and 3) SiO-activated macrophages promoted fibroblast proliferation and migration via the circHECTD1/HECTD1 pathway. Tissue samples from silicosis patients confirmed the upregulation of HECTD1. Our study elucidated a link between SiO-induced macrophage activation and the circHECTD1/HECTD1 pathway, thereby providing new insight into the potential use of HECTD1 in the development of novel therapeutic strategies for treating silicosis. 10.7150/thno.21648
Silica crystals and aluminum salts activate the NALP3 inflammasome through phagosomal destabilization. Hornung Veit,Bauernfeind Franz,Halle Annett,Samstad Eivind O,Kono Hajime,Rock Kenneth L,Fitzgerald Katherine A,Latz Eicke Nature immunology Inhalation of silica crystals causes inflammation in the alveolar space. Prolonged exposure to silica can lead to the development of silicosis, an irreversible, fibrotic pulmonary disease. The mechanisms by which silica and other crystals activate immune cells are not well understood. Here we demonstrate that silica and aluminum salt crystals activated inflammasomes formed by the cytoplasmic receptor NALP3. NALP3 activation required phagocytosis of crystals, and this uptake subsequently led to lysosomal damage and rupture. 'Sterile' lysosomal damage (without crystals) also induced NALP3 activation, and inhibition of either phagosomal acidification or cathepsin B activity impaired NALP3 activation. Our results indicate that the NALP3 inflammasome senses lysosomal damage as an endogenous 'danger' signal. 10.1038/ni.1631
Tetrandrine alleviates silicosis by inhibiting canonical and non-canonical NLRP3 inflammasome activation in lung macrophages. Acta pharmacologica Sinica Silicosis caused by inhalation of silica particles leads to more than ten thousand new occupational exposure-related deaths yearly. Exacerbating this issue, there are currently few drugs reported to effectively treat silicosis. Tetrandrine is the only drug approved for silicosis treatment in China, and despite more than decades of use, its efficacy and mechanisms of action remain largely unknown. Here, in this study, we established silicosis mouse models to investigate the effectiveness of tetrandrine of early and late therapeutic administration. To this end, we used multiple cardiopulmonary function test, as well as markers for inflammation and fibrosis. Moreover, using single cell RNA sequencing and transcriptomics of lung tissue and quantitative microarray analysis of serum from silicosis and control mice, our results provide a novel description of the target pathways for tetrandrine. Specifically, we found that tetrandrine attenuated silicosis by inhibiting both the canonical and non-canonical NLRP3 inflammasome pathways in lung macrophages. Taken together, our work showed that tetrandrine yielded promising results against silicosis-associated inflammation and fibrosis and further lied the groundwork for understanding its molecular targets. Our results also facilitated the wider adoption and development of tetrandirne, potentially accelerating a globally accepted therapeutic strategy for silicosis. 10.1038/s41401-021-00693-6
New Insights into Pathomechanisms and Treatment Possibilities for Lung Silicosis. Adamcakova Jana,Mokra Daniela International journal of molecular sciences Inhalation of silica particles is an environmental and occupational cause of silicosis, a type of pneumoconiosis. Development of the lung silicosis is a unique process in which the vicious cycle of ingestion of inhaled silica particles by alveolar macrophages and their release triggers inflammation, generation of nodular lesions, and irreversible fibrosis. The pathophysiology of silicosis is complex, and interactions between the pathomechanisms have not been completely understood. However, elucidation of silica-induced inflammation cascades and inflammation-fibrosis relations has uncovered several novel possibilities of therapeutic targeting. This article reviews new information on the pathophysiology of silicosis and points out several promising treatment approaches targeting silicosis-related pathways. 10.3390/ijms22084162
Silica-related diseases in the modern world. Hoy Ryan F,Chambers Daniel C Allergy Silicosis is an ancient and potentially fatal pneumoconiosis caused by exposure to respirable crystalline silica. Silicosis is historically a disease of miners; however, failure to recognize and control the risk associated with silica exposure in contemporary work practices such as sandblasting denim jeans and manufacturing of artificial stone benchtops has led to re-emergence of silicosis around the world. This review outlines the mineralogy, epidemiology, clinical and radiological features of the various forms of silicosis and other silica-associated diseases. Perspective is provided on the most recent studies shedding light on pathogenesis, including the central role of innate immune effector cells and subsequent inflammatory cascades in propagating pulmonary fibrosis and the extrapulmonary manifestations, which uniquely characterize this pneumoconiosis. Clinical conundrums in differential diagnosis, particularly between silicosis and sarcoidosis, are highlighted, as is the importance of obtaining a careful occupational history in the patient presenting with pulmonary infiltrates and/or fibrosis. While silicosis is a completely preventable disease, unfortunately workers around the world continue to be affected and experience progressive or even fatal disease. Although no treatments have been proven, opportunities to intervene to prevent progressive disease, founded in a thorough cellular and molecular understanding of the immunopathology of silicosis, are highlighted. 10.1111/all.14202
Macrophage Autophagy and Silicosis: Current Perspective and Latest Insights. Tan Shiyi,Chen Shi International journal of molecular sciences Silicosis is an urgent public health problem in many countries. Alveolar macrophage (AM) plays an important role in silicosis progression. Autophagy is a balanced mechanism for regulating the cycle of synthesis and degradation of cellular components. Our previous study has shown that silica engulfment results in lysosomal rupture, which may lead to the accumulation of autophagosomes in AMs of human silicosis. The excessive accumulation of autophagosomes may lead to apoptosis in AMs. Herein, we addressed some assumptions concerning the complex function of autophagy-related proteins on the silicosis pathogenesis. We also recapped the molecular mechanism of several critical proteins targeting macrophage autophagy in the process of silicosis fibrosis. Furthermore, we summarized several exogenous chemicals that may cause an aggravation or alleviation for silica-induced pulmonary fibrosis by regulating AM autophagy. For example, lipopolysaccharides or nicotine may have a detrimental effect combined together with silica dust via exacerbating the blockade of AM autophagic degradation. Simultaneously, some natural product ingredients such as atractylenolide III, dioscin, or trehalose may be the potential AM autophagy regulators, protecting against silicosis fibrosis. In conclusion, the deeper molecular mechanism of these autophagy targets should be explored in order to provide feasible clues for silicosis therapy in the clinical setting. 10.3390/ijms22010453
Dioscin Alleviates Crystalline Silica-Induced Pulmonary Inflammation and Fibrosis through Promoting Alveolar Macrophage Autophagy. Du Sitong,Li Chao,Lu Yiping,Lei Xue,Zhang Yiting,Li Siyi,Liu Fangwei,Chen Ying,Weng Dong,Chen Jie Theranostics Occupational exposure to crystalline silica (CS) particles leads to silicosis, which is characterized by chronic inflammation and abnormal tissue repair. Alveolar macrophages (AMs) play a crucial role in the process of silicosis. Previously, we demonstrated positive effect of dioscin on silicosis through modulating macrophage-elicited innate immune response. However, the concrete molecular mechanism remains to be discovered. We established experimental model of silicosis with wildtype and Atg5Dppa3 mice and oral administrated dioscin daily to explore the effects of dioscin on macrophages and pulmonary fibrosis. AM cell line MH-S with Atg5 silence was used to explore specific function of dioscin on macrophage-derived inflammation and the underlying molecular mechanism. Dioscin could promote autophagy in macrophages. Dioscin-triggered AMs autophagy limited mitochondrial reactive oxygen species (mtROS) mass stimulated by CS, reduced mitochondria-dependent apoptosis pathway activation and facilitated cell survival. Relieved oxidative stress resulted in decreased secretion of inflammatory factors and chemokines. Dioscin treatment alleviated macrophage-derived inflammation and subsequent abnormal collagen repair. All the dioscin's protective effects were diminished in Atg5Dppa3 mice. Dioscin promoting autophagy leads to reduced CS-induced mitochondria-dependent apoptosis and cytokine production in AMs, which may provide concrete molecular mechanism for the therapy of silicosis. 10.7150/thno.29682
Epigenetic Changes and Functions in Pneumoconiosis. Oxidative medicine and cellular longevity Pneumoconiosis is one of the most common occupational diseases in the world, and specific treatment methods of pneumoconiosis are lacking at present, so it carries great social and economic burdens. Pneumoconiosis, coronavirus disease 2019, and idiopathic pulmonary fibrosis all have similar typical pathological changes-pulmonary fibrosis. Pulmonary fibrosis is a chronic lung disease characterized by excessive deposition of the extracellular matrix and remodeling of the lung tissue structure. Clarifying the pathogenesis of pneumoconiosis plays an important guiding role in its treatment. The occurrence and development of pneumoconiosis are accompanied by epigenetic factors (e.g., DNA methylation and noncoding RNA) changes, which in turn can promote or inhibit the process of pneumoconiosis. Here, we summarize epigenetic changes and functions in the several kinds of evidence classification (epidemiological investigation, , and experiments) and main types of cells (macrophages, fibroblasts, and alveolar epithelial cells) to provide some clues for finding specific therapeutic targets for pneumoconiosis and even for pulmonary fibrosis. 10.1155/2022/2523066