MicroRNA-370 Attenuates Hepatic Fibrogenesis by Targeting Smoothened

Abstract

Background and Aims: Recent research shows that abnormal expression of microRNA plays an important role in the process of hepatic fibrosis. miR-370 has been reported to be involved in liver function and is suppressed during hepatic carcinogenesis. The aim of this study was to investigate the role of miR-370 in hepatic fibrosis. Methods: The expression levels of miR-370 in rat fibrotic livers and activated hepatic stellate cells (HSCs) were evaluated by quantitative real-time PCR. The effect of miR-370 on the activation of HSCs was analyzed by flow cytometric analyses, real-time PCR and Western blot. Adenovirus carrying miR-370 was injected through the tail vein to access the effect of miR-370 on hepatic fibrosis induced by CCl4 in rats. The downstream targets of miR-370 were predicted by the Target Scan database and verified by luciferase assays, real-time PCR and Western blot in HSCs and were further confirmed by immunohistochemistry in vivo. Results: Real-time PCR showed that miR-370 expression was significantly reduced in rat fibrotic livers and TGFβ1-stimulated HSCs. Overexpression of miR-370 inhibited the proliferation of HSC-T6 cells via inducing cell apoptosis and suppressed the activation of HSCs. Upregulation of miR-370 obviously attenuated the CCl4-induced liver fibrosis in rats. miR-370 was directly bound to the 3′UTR of Smoothened (SMO) and suppressed the expression of SMO in HSCs and fibrotic livers. Conclusions: Our study demonstrated that miR-370 plays an inhibitory role in hepatic fibrogenesis by targeting SMO. Restoration of miR-370 may have beneficial effects on the treatment of liver fibrosis.