miR-192 inhibits the activation of hepatic stellate cells by targeting Rictor

Abstract

The activation of hepatic stellate cells (HSCs) is regarded as the primary driving factor of liver fibrosis. miR-192, a miRNA associated with hepatocellular carcinoma and enriched in HSCs, has an undisclosed role in HSC activation and liver fibrosis. In this study, a CCl4-induced rat liver fibrosis model and transforming growth factor-beta 1 (TGF-β1)-treated HSC lines (LX-2 and HSC-T6) were used to detect miR-192 and Rictor levels in vivo and in vitro. Bioinformatic analysis and a dual luciferase assay were used to predict and confirm the interaction of Rictor with miR-192. Gain- and/or loss-of-function methods evaluated molecular changes and HSC activation phenotypes, detected by quantitative real-time PCR, western blotting, and immunofluorescence. We observed a gradual downregulation of miR-192 and upregulation of Rictor during CCl4-induced liver fibrosis/cirrhosis in rats. Enriched miR-192 was downregulated, while Rictor was upregulated in TGF-β1-activated HSCs. miR-192 inhibited the activation of HSCs by directly targeting Rictor. High miR-192/low Rictor expression attenuated the fibrotic-related gene expression by AKT/mTORC2 signaling. In conclusion, miR-192 could inhibit the activation of HSCs by directly targeting Rictor in the AKT/mTORC2 signaling pathway. This study provides insights into potential therapeutic targets for liver fibrosis and cirrhosis.

Keywords

• liver fibrosis
• microrna-192
• rictor
• hepatic stellate cell
• smad