Dataset Information

Blockade of C5aR1 alleviates liver inflammation and fibrosis in a mouse model of NASH by regulating TLR4 signaling and macrophage polarization.

ABSTRACT:

Background

Nonalcoholic steatohepatitis (NASH) is an advanced form of chronic fatty liver disease, which is a driver of hepatocellular carcinoma. However, the roles of the C5aR1 in the NASH remain poorly understood. Here, we aimed to investigate the functions and mechanisms of the C5aR1 on hepatic inflammation and fibrosis in murine NASH model.

Methods

Mice were fed a normal chow diet with corn oil (ND + Oil), a Western diet with corn oil (WD + Oil) or a Western diet with carbon tetrachloride (WD + CCl₄) for 12 weeks. The effects of the C5a-C5aR1 axis on the progression of NASH were analyzed and the underlying mechanisms were explored.

Results

Complement factor C5a was elevated in NASH mice. C5 deficiency reduced hepatic lipid droplet accumulation in the NASH mice. The hepatic expression levels of TNFα, IL-1β and F4/80 were decreased in C5-deficient mice. C5 loss alleviated hepatic fibrosis and downregulated the expression levels of α-SMA and TGFβ1. C5aR1 deletion reduced inflammation and fibrosis in NASH mice. Transcriptional profiling of liver tissues and KEGG pathway analysis revealed that several pathways such as Toll-like receptor signaling, NFκB signaling, TNF signaling, and NOD-like receptor signaling pathway were enriched between C5aR1 deficiency and wild-type mice. Mechanistically, C5aR1 deletion decreased the expression of TLR4 and NLRP3, subsequently regulating macrophage polarization. Moreover, C5aR1 antagonist PMX-53 treatment mitigated the progression of NASH in mice.

Conclusions

Blockade of the C5a-C5aR1 axis reduces hepatic steatosis, inflammation, and fibrosis in NASH mice. Our data suggest that C5aR1 may be a potential target for drug development and therapeutic intervention of NASH.

SUBMITTER: Jiang K

PROVIDER: S-EPMC10423130 | biostudies-literature | 2023 Sep

REPOSITORIES: biostudies-literature

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Publications

Blockade of C5aR1 alleviates liver inflammation and fibrosis in a mouse model of NASH by regulating TLR4 signaling and macrophage polarization.

Jiang Keqing K Lu Shibang S Li Dongxiao D Liu Mingjiang M Jin Hu H Lei Biao B Wang Sifan S Long Kang K He Songqing S Zhong Fudi F

Journal of gastroenterology 20230525 9

<h4>Background</h4>Nonalcoholic steatohepatitis (NASH) is an advanced form of chronic fatty liver disease, which is a driver of hepatocellular carcinoma. However, the roles of the C5aR1 in the NASH remain poorly understood. Here, we aimed to investigate the functions and mechanisms of the C5aR1 on hepatic inflammation and fibrosis in murine NASH model.<h4>Methods</h4>Mice were fed a normal chow diet with corn oil (ND + Oil), a Western diet with corn oil (WD + Oil) or a Western diet with carbon t ...[more]

PMID: 37227481

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Project description:Background & aimsNOD-like receptor protein 3 (NLRP3) inflammasome activation occurs in Non-alcoholic fatty liver disease (NAFLD). We used the first small molecule NLRP3 inhibitor, MCC950, to test whether inflammasome blockade alters inflammatory recruitment and liver fibrosis in two murine models of steatohepatitis.MethodsWe fed foz/foz and wild-type mice an atherogenic diet for 16weeks, gavaged MCC950 or vehicle until 24weeks, then determined NAFLD phenotype. In mice fed an methionine/choline deficient (MCD) diet, we gavaged MCC950 or vehicle for 6weeks and determined the effects on liver fibrosis.ResultsIn vehicle-treated foz/foz mice, hepatic expression of NLRP3, pro-IL-1β, active caspase-1 and IL-1β increased at 24weeks, in association with cholesterol crystal formation and NASH pathology; plasma IL-1β, IL-6, MCP-1, ALT/AST all increased. MCC950 treatment normalized hepatic caspase 1 and IL-1β expression, plasma IL-1β, MCP-1 and IL-6, lowered ALT/AST, and reduced the severity of liver inflammation including designation as NASH pathology, and liver fibrosis. In vitro, cholesterol crystals activated Kupffer cells and macrophages to release IL-1β; MCC950 abolished this, and the associated neutrophil migration. MCD diet-fed mice developed fibrotic steatohepatitis; MCC950 suppressed the increase in hepatic caspase 1 and IL-1β, lowered numbers of macrophages and neutrophils in the liver, and improved liver fibrosis.ConclusionMCC950, an NLRP3 selective inhibitor, improved NAFLD pathology and fibrosis in obese diabetic mice. This is potentially attributable to the blockade of cholesterol crystal-mediated NLRP3 activation in myeloid cells. MCC950 reduced liver fibrosis in MCD-fed mice. Targeting NLRP3 is a logical direction in pharmacotherapy of NASH.Lay summaryFatty liver disease caused by being overweight with diabetes and a high risk of heart attack, termed non-alcoholic steatohepatitis (NASH), is the most common serious liver disease with no current treatment. There could be several causes of inflammation in NASH, but activation of a protein scaffold within cells termed the inflammasome (NLRP3) has been suggested to play a role. Here we show that cholesterol crystals could be one pathway to activate the inflammasome in NASH. We used a drug called MCC950, which has already been shown to block NLRP3 activation, in an attempt to reduce liver injury in NASH. This drug partly reversed liver inflammation, particularly in obese diabetic mice that most closely resembles the human context of NASH. In addition, such dampening of liver inflammation in NASH achieved with MCC950 partly reversed liver scarring, the process that links NASH to the development of cirrhosis.

Project description:ObjectiveM6A methylation-regulated macrophages play an important role in the occurrence and development of arteriosclerosis. However, their role in lower extremity arteriosclerosis remains unclear. Therefore, this study aims to explore the key factors that regulate arteriosclerosis methylation in the lower extremities and the mechanism by which they affect arteriosclerosis by influencing macrophage polarization.MethodsThe m6A methylation levels in peripheral blood mononuclear cells (PBMCs) of patients with lower extremity atherosclerosis was investigated using the Dot blot method. Additionally, the expression levels of RNA methyltransferases and demethylases were examined using ELISA and Western blotting. Inflammatory macrophages were established using RAW264.7 cells stimulated with LPS (100 ng/mL), and the expression of ALKBH5 and ITGB1 was evaluated using Western blotting. Immunofluorescence staining was conducted to assess the expression of M1 macrophage markers (F4/80+CD86) and M2 macrophage markers (F4/80+CD206) in renal tissue. ELISA was employed to measure the levels of cytokines (IL-6, IL-1β, TNF-a, IL-10, and TGF-β) and plasma lipid levels in mice. An atherosclerosis model was established in ApoE-/- mice through balloon pull surgery and high-fat feeding. Oil Red O staining and hematoxylin and eosin (HE) staining were performed to measure the area of atherosclerotic plaques and the size of the necrotic core in mouse femoral artery, respectively. Additionally, Starbase2.0 was used for downstream target gene prediction of ALKBH5. The half-life of ITGB1 was evaluated using RT-qPCR.ResultsThe m6A methylation levels were significantly increased in PBMCs of patients with lower extremity atherosclerosis. Among them, the expression of the RNA demethylase ALKBH5 was the lowest in PBMCs of patients with lower extremity atherosclerosis. Further analysis revealed that ALKBH5 can alleviate the progression of lower extremity atherosclerosis and promote the polarization of M2 macrophages. ALKBH5 can reduce the stability of ITGB1 through demethylation. Mechanistically, ALKBH5 influences macrophage polarization and mitigates lower extremity atherosclerosis by affecting the demethylation of ITGB1.ConclusionALKBH5 promotes M2 macrophage polarization and alleviates lower extremity atherosclerosis by regulating the demethylation of ITGB1. A deeper understanding of this process not only helps elucidate the molecular mechanisms of atherosclerosis but also provides possibilities for the development of new therapeutic strategies.

Dataset Information

Blockade of C5aR1 alleviates liver inflammation and fibrosis in a mouse model of NASH by regulating TLR4 signaling and macrophage polarization.

Background

Methods

Results

Conclusions

Publications

Blockade of C5aR1 alleviates liver inflammation and fibrosis in a mouse model of NASH by regulating TLR4 signaling and macrophage polarization.

Similar Datasets

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