Earthworm extract attenuates silica-induced pulmonary fibrosis through Nrf2-dependent mechanisms.
Yang Jingjin,Wang Ting,Li Yan,Yao Wenxi,Ji Xiaoming,Wu Qiuyun,Han Lei,Han Ruhui,Yan Weiwen,Yuan Jiali,Ni Chunhui
Laboratory investigation; a journal of technical methods and pathology
Silicosis is an occupational pulmonary fibrosis caused by inhalation of silica (SiO) and there are no ideal drugs to treat this disease. Earthworm extract (EE), a natural nutrient, has been reported to have anti-inflammatory, antioxidant, and anti-apoptosis effects. The purpose of the current study was to test the protective effects of EE against SiO-induced pulmonary fibrosis and to explore the underlying mechanisms using both in vivo and in vitro models. We found that treatment with EE significantly reduced lung inflammation and fibrosis and improved lung structure and function in SiO-instilled mice. Further mechanistic investigations revealed that EE administration markedly inhibited SiO-induced oxidative stress, mitochondrial apoptotic pathway, and epithelial-mesenchymal transition in HBE and A549 cells. Furthermore, we demonstrate that Nrf2 activation partly mediates the interventional effects of EE against SiO-induced pulmonary fibrosis. Our study has identified EE to be a potential anti-oxidative, anti-inflammatory, and anti-fibrotic drug for silicosis.
The CDR1as/miR-7/TGFBR2 Axis Modulates EMT in Silica-Induced Pulmonary Fibrosis.
Yao Wenxi,Li Yan,Han Lei,Ji Xiaoming,Pan Honghong,Liu Yi,Yuan Jiali,Yan Weiwen,Ni Chunhui
Toxicological sciences : an official journal of the Society of Toxicology
Silicosis is one of the typical forms of pneumoconiosis characterized by abnormal proliferation of fibroblasts and deposition of extracellular matrix. Recent findings have shown that microRNAs and circular RNAs (circRNAs) are implicated in many diseases. However, the function of noncoding RNAs in pulmonary fibrosis remain to be elucidated. Here, miR-7 was found significantly decreased in silica-treated pulmonary epithelial cells as well as in fibrotic lung tissues of mice. Elevated expression of miR-7 via agomir injection relieved lung fibrosis in vivo. Further molecular study showed that miR-7 played its role against pulmonary fibrosis by blocking epithelial-mesenchymal transition (EMT) progression of human bronchial epithelial cells and A549 cells. Notably, transforming growth factor beta receptor 2 (TGFBR2) was identified as a target gene of miR-7 with bioinformatics tools, which was verified by dual luciferase receptor gene assay in human bronchial epithelial cells and A549 cells. Silica induced elevation of TGFBR2 could be abolished by exogenous expression of miR-7. Furthermore, bioinformatics software indicated that circRNA CDR1as had several binding sites for miR-7. The inhibitory effects of miR-7 on EMT and its target TGFBR2 were suppressed by circRNA CDR1as, which contributed to pulmonary fibrosis. Our studies also revealed overexpressed miR-7 could repress fibrogenesis of lung fibroblasts induced by TGF-β1. Collectively, circRNA CDR1as stimulated by silica could sponge miR-7 to release TGFBR2, plays an important role during pulmonary fibrosis by promoting EMT process. These results indicated that the interaction between miR-7 and circRNA CDR1as may exert important functions and provide potential therapeutic targets in lung fibrotic diseases.
[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.
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
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.
NLRP3 inflammasome inhibition attenuates silica-induced epithelial to mesenchymal transition (EMT) in human bronchial epithelial cells.
Li Xiang,Yan Xiaopei,Wang Yanli,Wang Jingjing,Zhou Fang,Wang Hong,Xie Weiping,Kong Hui
Experimental cell research
Silicosis is an incurable and progressive lung disease characterized by chronic inflammation and fibroblasts accumulation. Studies have indicated a vital role for epithelial-mesenchymal transition (EMT) in fibroblasts accumulation. NLRP3 inflammasome is a critical mediator of inflammation in response to a wide range of stimuli (including silica particles), and plays an important role in many respiratory diseases. However, whether NLRP3 inflammasome regulates silica-induced EMT remains unknown. Our results showed that silica induced EMT in human bronchial epithelial cells (16HBE cells) in a dose- and time-dependent manner. Meanwhile, silica persistently activated NLRP3 inflammasome as indicated by continuously elevated extracellular levels of interleukin-1β (IL-1β) and IL-18. NLRP3 inflammasome inhibition by short hairpin RNA (shRNA)-mediated knockdown of NLRP3, selective inhibitor MCC950, and caspase-1 inhibitor Z-YVAD-FMK attenuated silica-induced EMT. Western blot analysis indicated that TAK1-MAPK-Snail/NF-κB pathway involved NLRP3 inflammasome-mediated EMT. Moreover, pirfenidone, a commercially and clinically available drug approved for treating idiopathic pulmonary fibrosis (IPF), effectively suppressed silica-induced EMT of 16HBE cells in line with NLRP3 inflammasome inhibition. Collectively, our results indicate that NLRP3 inflammasome is a promising target for blocking or retarding EMT-mediated fibrosis in pulmonary silicosis. On basis of this mechanism, pirfenidone might be a potential drug for the treatment of silicosis.
SB203580 inhibits epithelial-mesenchymal transition and pulmonary fibrosis in a rat silicosis model.
Yan Wang,Xiaoli Li,Guoliang An,Zhonghui Zhu,Di Liang,Ximeng Lian,Piye Niu,Li Chen,Lin Tian
To investigate the role of p38 MAPK in silicosis, we explored the effects of SB203580 as a specific inhibitor of p38 MAPK in the silicosis model in rats. Rats were exposed to 50mg/ml silica intratracheally. From the first day after instillation, rats were injected with SB203580 1mg/kg/d. Rats were sacrificed at 7 and 15days after exposure of silica. The results demonstrated SB203580 could prevent the activation of p38. TGF-β1 in bronchoalveolar lavage fluid, the expression of vimentin and α-SMA in the lung tissue was down-regulated and E-cadherin was up-regulated after intervention with SB203580 at 7days and 15days. The percentage of the cells staining with SP-C and vimentin doubly was lower in SB203580 treated group than in silica group at 7days and 15days. SB203580 also inhibited the increase of ZEB-1, ZEB-2 and Twist at 7days. Histopathologic examination showed the decrease in the number of nodules and the blue areas of collagen fibers in the lung after SB203580 treatment. The content of hydroxyproline and the expression of collagen I and III decreased in SB203580 treated group than in silica group. These results suggested that p38 MAPK/ZEB-1 (ZEB-2, Twist) pathway was involved at 7days after silica instillation and p38 MAPK was pivotal for EMT in silicosis fibrosis in rats.