Short hairpin RNA attenuates liver fibrosis by regulating the peroxisome proliferator-activated receptor-γ and nuclear factor-κB pathways in hepatitis B virus-induced liver fibrosis in mice

Abstract Background: Progressive liver fibrosis, caused by chronic viral infection and metabolic disorders, results in the development of cirrhosis and hepatocellular carcinoma. However, no antifibrotic therapies have been approved to date. In our previous study, adeno-associated virus (AAV) short hairpin RNAs (shRNAs) targeting hepatitis B virus (HBV) and transforming growth factor (TGF)-β administration could persistently inhibit HBV replication and concomitantly prevent liver fibrosis. However, the differentially expressed proteins and critical regulatory networks of AAVshRNA treatment remain unclear. Accordingly, in this study, our major goal was we aimed to analyze differentially expressed proteins in the liver of AAV-shRNAs-treated mice with HBV infection and liver fibrosis using isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics and to elucidate the underlying antifibrotic mechanisms. Results: In total 2743 proteins were recognized by iTRAQ-based quantitative proteomics analysis. Gene ontology analysis suggested that the differentially expressed proteins were mostly participated in peptide metabolism in the biological process category, cytosolic ribosomes in the cell component category, and structural constituents of ribosomes in the molecular function category. Kyoto Encyclopedia of Genes and Genomespathway analysis indicated that oxidative stress and the peroxisome proliferator-activated receptor (PPAR) signaling pathway were actived after treatment. Verification studies showed that AAVshRNAs inhibited hepatic stellate cell activation and inflammation by suppressing nuclear factor-κB p65 phosphorylation and α-smooth muscle actin expression via upregulation of PPAR-γ. Hepatocytes steatosis was also decreased by activating PPAR signaling pathway and improving lipid metabolism. TGF-β level was decreased owning to increase PPAR-γ expression and directly inhibition using AAVshRNAs targeting TGF-β. TGF-β-induced oxidative stress was suppressed by increasing glutathione S-transferase Pi 1 and reducing peroxiredoxin 1. Conclusions: Our results indicated that AAV-shRNAs were effective for modulating liver fibrosis by reducing oxidative stress, inflammation and activating PPAR signaling pathway.