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Macrophage migration inhibitory factor is regulated by HIF-1α and cAMP and promotes renal cyst cell proliferation in a macrophage-independent manner. Journal of molecular medicine (Berlin, Germany) Progressive cyst growth leads to decline of renal function in polycystic kidney disease. Macrophage migration inhibitory factor (MIF) was found to be upregulated in cyst-lining cells in a mouse model of polycystic kidney disease and to promote cyst growth. In addition, MIF can be secreted by tubular cells and may contribute to cyst growth in an autocrine manner. However, the underlying mechanisms leading to induction of MIF in cyst-lining cells remained elusive. Here, we demonstrate that hypoxia-inducible transcription factor (HIF) 1α upregulates MIF in cyst-lining cells in a tubule-specific PKD1 knockout mouse. Pharmacological stabilization of HIF-1α resulted in significant increase of MIF in cyst epithelial cells whereas tubule-specific knockout of HIF-1α prevented MIF upregulation. Identical regulation could be found for ABCA1, which has been shown to act as a transport protein for MIF. Furthermore, we show that MIF and ABCA1 are direct target genes of HIF-1α in human primary tubular cells. Next to HIF-1α and hypoxia, we found MIF being additionally regulated by cAMP which is a strong promotor of cyst growth. In line with these findings, HIF-1α- and cAMP-dependent in vitro cyst growth could be decreased by the MIF-inhibitor ISO-1 which resulted in reduced cyst cell proliferation. In conclusion, HIF-1α and cAMP regulate MIF in primary tubular cells and cyst-lining epithelial cells, and MIF promotes cyst growth in the absence of macrophages. In line with these findings, the MIF inhibitor ISO-1 attenuates HIF-1α- and cAMP-dependent in vitro cyst enlargement. KEY MESSAGES: • MIF is upregulated in cyst-lining cells in a polycystic kidney disease mouse model. • MIF upregulation is mediated by hypoxia-inducible transcription factor (HIF) 1α. • ABCA1, transport protein for MIF, is also regulated by HIF-1α in vitro and in vivo. • MIF is additionally regulated by cAMP, a strong promotor of cyst growth. • MIF-inhibitor ISO-1 reduces HIF-1α- and cAMP-dependent cyst growth. 10.1007/s00109-020-01964-1
HIF-1α (Hypoxia-Inducible Factor-1α) Promotes Macrophage Necroptosis by Regulating miR-210 and miR-383. Karshovska Ela,Wei Yuanyuan,Subramanian Pallavi,Mohibullah Rokia,Geißler Claudia,Baatsch Isabelle,Popal Aamoun,Corbalán Campos Judit,Exner Nicole,Schober Andreas Arteriosclerosis, thrombosis, and vascular biology OBJECTIVE:Inflammatory activation changes the mitochondrial function of macrophages from oxidative phosphorylation to reactive oxygen species production, which may promote necrotic core formation in atherosclerotic lesions. In hypoxic and cancer cells, HIF-1α (hypoxia-inducible factor) promotes oxygen-independent energy production by microRNAs. Therefore, we studied the role of HIF-1α in the regulation of macrophage energy metabolism in the context of atherosclerosis. Approach and Results: Myeloid cell-specific deletion of reduced atherosclerosis and necrotic core formation by limiting macrophage necroptosis in apolipoprotein E-deficient mice. In inflammatory bone marrow-derived macrophages, deletion of increased oxidative phosphorylation, ATP levels, and the expression of genes encoding mitochondrial proteins and reduced reactive oxygen species production and necroptosis. microRNA expression profiling showed that HIF-1α upregulates and downregulates levels in lesional macrophages and inflammatory bone marrow-derived macrophages. In contrast to , which inhibited oxidative phosphorylation and enhanced mitochondrial reactive oxygen species production, increased ATP levels and inhibited necroptosis. The effect of miR-210 was due to targeting 2,4-dienoyl-CoA reductase, which is essential in the β oxidation of unsaturated fatty acids. affected the DNA damage repair pathway in bone marrow-derived macrophages by targeting poly(ADP-ribose)-glycohydrolase (Parg), which reduced energy consumption and increased cell survival. Blocking the targeting of Parg by prevented the protective effect of deletion in macrophages on atherosclerosis and necrotic core formation in mice. CONCLUSIONS:Our findings unveil a new mechanism by which activation of HIF-1α in inflammatory macrophages increases necroptosis through microRNA-mediated ATP depletion, thus increasing atherosclerosis by necrotic core formation. 10.1161/ATVBAHA.119.313290
Tubular epithelial cell-derived extracellular vesicles induce macrophage glycolysis by stabilizing HIF-1α in diabetic kidney disease. Molecular medicine (Cambridge, Mass.) BACKGROUND:Albuminuria is a hallmark of diabetic kidney disease (DKD) that promotes its progression, leading to renal fibrosis. Renal macrophage function is complex and influenced by macrophage metabolic status. However, the metabolic state of diabetic renal macrophages and the impact of albuminuria on the macrophage metabolic state are poorly understood. METHODS:Extracellular vesicles (EVs) from tubular epithelial cells (HK-2) were evaluated using transmission electron microscopy, nanoparticle tracking analysis and western blotting. Glycolytic enzyme expression in macrophages co-cultured with HSA-treated HK-2 cell-derived EVs was detected using RT-qPCR and western blotting. The potential role of EV-associated HIF-1α in the mediation of glycolysis was explored in HIF-1α siRNA pre-transfected macrophages co-cultured with HSA-treated HK-2 cell-derived EVs, and the extent of HIF-1α hydroxylation was measured using western blotting. Additionally, we injected db/db mice with EVs via the caudal vein twice a week for 4 weeks. Renal macrophages were isolated using CD11b microbeads, and immunohistofluorescence was applied to confirm the levels of glycolytic enzymes and HIF-1α in these macrophages. RESULTS:Glycolysis was activated in diabetic renal macrophages after co-culture with HSA-treated HK-2 cells. Moreover, HSA-treated HK-2 cell-derived EVs promoted macrophage glycolysis both in vivo and in vitro. Inhibition of glycolysis activation in macrophages using the glycolysis inhibitor 2-DG decreased the expression of both inflammatory and fibrotic genes. Mechanistically, EVs from HSA-stimulated HK-2 cells were found to accelerate macrophage glycolysis by stabilizing HIF-1α. We also found that several miRNAs and lncRNAs, which have been reported to stabilize HIF-1α expression, were increased in HSA-treated HK-2 cell-derived EVs. CONCLUSION:Our study suggested that albuminuria induced renal macrophage glycolysis through tubular epithelial cell-derived EVs by stabilizing HIF-1α, indicating that regulation of macrophage glycolysis may offer a new treatment strategy for DKD patients, especially those with macroalbuminuria. 10.1186/s10020-022-00525-1
Indoxyl Sulfate Contributes to mTORC1-Induced Renal Fibrosis via The OAT/NADPH Oxidase/ROS Pathway. Nakano Takehiro,Watanabe Hiroshi,Imafuku Tadashi,Tokumaru Kai,Fujita Issei,Arimura Nanaka,Maeda Hitoshi,Tanaka Motoko,Matsushita Kazutaka,Fukagawa Masafumi,Maruyama Toru Toxins Activation of mTORC1 (mechanistic target of rapamycin complex 1) in renal tissue has been reported in chronic kidney disease (CKD)-induced renal fibrosis. However, the molecular mechanisms responsible for activating mTORC1 in CKD pathology are not well understood. The purpose of this study was to identify the uremic toxin involved in mTORC1-induced renal fibrosis. Among the seven protein-bound uremic toxins, only indoxyl sulfate (IS) caused significant activation of mTORC1 in human kidney 2 cells (HK-2 cells). This IS-induced mTORC1 activation was inhibited in the presence of an organic anion transporter inhibitor, a NADPH oxidase inhibitor, and an antioxidant. IS also induced epithelial-mesenchymal transition of tubular epithelial cells (HK-2 cells), differentiation of fibroblasts into myofibroblasts (NRK-49F cells), and inflammatory response of macrophages (THP-1 cells), which are associated with renal fibrosis, and these effects were inhibited in the presence of rapamycin (mTORC1 inhibitor). In in vivo experiments, IS overload was found to activate mTORC1 in the mouse kidney. The administration of AST-120 or rapamycin targeted to IS or mTORC1 ameliorated renal fibrosis in Adenine-induced CKD mice. The findings reported herein indicate that IS activates mTORC1, which then contributes to renal fibrosis. Therapeutic interventions targeting IS and mTORC1 could be effective against renal fibrosis in CKD. 10.3390/toxins13120909
Distinct roles of HMGB1 in the regulation of P‑glycoprotein expression in the liver and kidney of mice with lipopolysaccharide‑induced inflammation. Molecular medicine reports The role of high mobility group box 1 (HMGB1) in the regulation of efflux transporters in the liver and kidney remains unclear, although it has been reported that HMGB1 can increase P‑glycoprotein (P‑gp) expression in the brain. The present study aimed to clarify the involvement of HMGB1 in the regulation of P‑gp expression in the liver and kidney of mice with lipopolysaccharide (LPS)‑induced inflammation. Mice were treated with LPS or LPS + glycyrrhizin (GL); GL is as an HMGB1 inhibitor. Subsequently, the expression levels of transporters, such as P‑gp, and HMGB1 receptors, such as toll‑like receptor (TLR)4 and receptor for advanced glycation end‑products (RAGE), were determined by quantitative PCR and LC‑MS/MS‑based targeted proteomics. For the study, HepG2 and KMRC‑1 cells were used, as was a co‑culture of KMRC‑1 and differentiated THP‑1 cells. The mRNA and protein expression levels of and in the kidneys of LPS + GL‑treated mice were significantly decreased compared with those in LPS mice. The results indicated that HMGB1 had little effect on the expression of and in the liver, since there was little change in of Mdr1a and Mdr1b expression between the LPS and LPS + GL‑treated mice. Notably, regarding mRNA expression, KMRC‑1 cells were more responsive to LPS than HepG2 cells, and KMRC‑1 cells treated with LPS exhibited increased levels compared with control KMRC‑1 cells. In differentiated THP‑1 cells, LPS treatment decreased the mRNA expression levels of , whereas they were restored to control levels by HMGB1. In conclusion, HMGB1 in the plasma and TLR4 in macrophages may be involved in the regulation of P‑gp expression in the kidneys of inflamed mice. 10.3892/mmr.2022.12858
Identification of Fibrotic Biomarkers Associated with Macrophages in Diabetic Nephropathy. Medical science monitor : international medical journal of experimental and clinical research BACKGROUND Diabetic nephropathy (DN) is the main cause of end-stage renal disease. Renal fibrosis is an important pathological feature of kidney injury, and the therapeutic means are very limited. The functions of macrophages play important roles in renal fibrosis. There is a complicated link between altered immune metabolism and oxidative stress. Hence, we designed this study to identify the oxidative stress- and macrophage-relevant biomarkers reflecting fibrosis in DN. MATERIAL AND METHODS Differential expression analysis was performed based on the GSE96804 dataset. xCell and weighted gene co-expression network analysis were used to determine the distinctions in infiltrating immune cells between DN and control specimens. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were conducted. A protein-protein interaction network was constructed to identify the hub genes. Hub genes were validated in an external dataset, GSE30528, and cell models. RESULTS MMP2, CASP3, and HIF-1alpha were identified as biomarkers, which were upregulated in the DN group and positively correlated with the infiltration of macrophages and M1 macrophages. In vitro, the 3 genes were highly expressed in murine MPC5 cells treated with high glucose and human THP-1 macrophages treated with advanced glycation end products. CONCLUSIONS Our results provided biomarkers for predicting the fibrotic progression of DN and confirmed that MMP2, CAPS3, and HIF-1alpha have good diagnostic value. They might be involved in the progression of DN fibrosis by regulating oxidative stress and macrophage recruitment or polarization. 10.12659/MSM.940847
Overexpression of Sirt6 promotes M2 macrophage transformation, alleviating renal injury in diabetic nephropathy. Ji Liqiang,Chen Yifang,Wang Hongqiang,Zhang Wei,He Lanxiang,Wu Jingmin,Liu Yinghui International journal of oncology In this study, we aimed to investigate the associations between Sirt6, macrophages and diabetic nephropathy (DN). Immunohistochemical, western blot and RT‑qPCR analyses were performed to detect the expression levels of Sirt6, the markers of podocytes and monocytes and related inflammatory factors in the tissues of rats with streptozocin‑induced DN. A series of cell experiments in isolated culture or the co‑culture of macrophages and podocytes were conducted to examine the effects of the overexpression of Sirt6 on macrophage transformation, podocyte apoptosis and associated genes, and analyses were performed using RT‑qPCR, flow cytometry and western blot analysis, where appropriate. In the rat model of DN, injured podocytes were represented by the decreased protein expression levels of Nephrin and Sirt6, and by an increased Desmin expression. Additionally, the M1 phenotype transformation of macrophages was evidenced by the increased expression levels of CD86, tumor necrosis factor (TNF)‑α and inducible nitric oxide synthase (iNOS), and by the decreased expression levels of CD206, Sirt6, interleukin (IL)‑4 and IL‑10. In vitro assays of macrophages and podocytes demonstrated that glucose promoted macrophage M1 transformation and podocyte apoptosis in a dose‑dependent manner and attenuated Sirt6 expression. Macrophages transformed into the M2 phenotype following the overexpression of Sirt6 by the successful transfection of macrophages with a Sirt6 overexpression plasmid. Sirt6 was also overexpressed in podocytes. In a Transwell co‑culture system, the overexpression of Sirt6 in macrophages (but not the overexpression of Sirt6 in podocytes) protected the podocytes from high‑glucose‑induced injury. However, the apoptosis of the podocytes overexpressing Sirt6 (induced by transfection with a Sirt6 overexpression plasmid) still increased when these podocytes were co‑cultured with macrophages in high‑glucose medium. These protective effects were evidenced by the inhibition of apoptosis, the upregulation of the expression levels of Bcl‑2 and CD206, as well as by the decreased expression levels of Bax and CD86. On the whole, the findings of this study suggest that Sirt6 protects podocytes against injury in a mimicked diabetic kidney microenvironment by activating M2 macrophages, indicating that Sirt6 can act as an immune response regulatory factor in DN‑associated renal inflammatory injury. 10.3892/ijo.2019.4800
TNF-α/HMGB1 inflammation signalling pathway regulates pyroptosis during liver failure and acute kidney injury. Wang Yao,Zhang Haiyue,Chen Qian,Jiao Fangzhou,Shi Chunxia,Pei Maohua,Lv Jian,Zhang Hong,Wang Luwen,Gong Zuojiong Cell proliferation OBJECTIVE:Acute kidney injury (AKI) is a common complication of acute liver failure (ALF). Pyroptosis is a necrosis type related to inflammation. This study aimed to investigate the role of TNF-α/HMGB1 pathway in pyroptosis during ALF and AKI. METHODS:An ALF and AKI mouse model was generated using LPS/D-Gal, and a TNF-α inhibitor, CC-5013, was used to treat the mice. THP-1 cells were induced to differentiate into M1 macrophages, then challenged with either CC-5013 or an HMGB1 inhibitor, glycyrrhizin. pLVX-mCMVZsGreen-PGK-Puros plasmids containing TNF-α wild-type (WT), mutation A94T of TNF-α and mutation P84L of TNF-α were transfected into M1 macrophages. RESULTS:Treatment with CC-5013 decreased the activation of TNF-α/HMGB1 pathway and pyroptosis in the treated mice and cells compared with the control mice and cells. CC-5013 also ameliorated liver and kidney pathological changes and improved liver and renal functions in treated mice, and the number of M1 macrophages in the liver and kidney tissues also decreased. The activation of TNF-α/HMGB1 pathway and pyroptosis increased in the M1 macrophage group compared with the normal group. Similarly, the activation of TNF-α/HMGB1 pathway and pyroptosis in the LPS + WT group also increased. By contrast, the activation of the TNF-α/HMGB1 pathway and pyroptosis decreased in the LPS + A94T and LPS + P84L groups. Moreover, glycyrrhizin inhibited pyroptosis. CONCLUSION:The TNF-α/HMGB1 inflammation signalling pathway plays an important role in pyroptosis during ALF and AKI. 10.1111/cpr.12829
Oridonin Alleviates IRI-Induced Kidney Injury by Inhibiting Inflammatory Response of Macrophages via AKT-Related Pathways. Yan Ying,Tan Rui-Zhi,Liu Peng,Li Jian-Chun,Zhong Xia,Liao Yuan,Lin Xiao,Wei Cong,Wang Li Medical science monitor : international medical journal of experimental and clinical research BACKGROUND Acute kidney injury (AKI) is one of the most common complications in clinic, but there is still no effective treatment. Oridonin, extracted from Rabdosia rubescens, has been identified to promote inhibitory effects on tumor, inflammatory and fibrosis by previous study. This study aimed to assess the kidney-protective role of Oridonin in AKI and the underlying mechanism by which Oridonin improves AKI in vivo and inhibits inflammation in LPS-induced bone marrow-derived macrophages (BMDM) in vitro. MATERIAL AND METHODS SPF C57BL/6J male mice (8 - 10 weeks old, body weight 20 - 25 g) were divided into 3 groups - sham group, AKI group, and Oridonin-treated AKI group - with 6 mice in each group. In the in vitro study, LPS-induced inflammatory BMDM cells were treated with Oridonin and agonist of AKT. The expression and secretion levels of inflammation-related indicators and AKT-related signaling molecules were detected by real-time PCR, ELISA, Western blot, and immunofluorescence. Also, various methods are used to assess renal function and pathological changes. RESULTS The results showed that Oridonin treatment significantly improved the serum creatinine and BUN levels in AKI mice. Interestingly, treatment with Oridonin also resulted in decreased the infiltration of macrophages in renal tissues of AKI mice, which was associated with decreased expression and activation of AKT and its related signaling pathways, such as NF-kappaB and STAT3, suggesting that Oridonin attenuates AKI kidney injury via a mechanism associated with reducing the inflammatory response of macrophages in the AKI kidney. This was investigated in vitro in macrophages, and the results showed that Oridonin reduced the LPS-stimulated inflammatory response in macrophages. Mechanistically, the addition of Oridonin reversed LPS-induced downregulation of AKT, NF-kappaB, and STAT3 expression and inflammatory response in macrophages, suggesting that Oridonin has a protective role, via the AKT-related signaling pathways, in reducing the inflammatory response of macrophages in AKI mice. This was further confirmed by adding agonist of AKT of IGF-1 to block the inhibitory effect of Oridonin on inflammatory response in vitro. CONCLUSIONS Oridonin ameliorates AKI kidney injuries by suppressing AKT-mediated inflammatory response of macrophages. 10.12659/MSM.921114