Abstract
We explored the role of microRNA-30a (miR-30a) and the mechanism involved in hepatic fibrosis. MiR-30a overexpression was achieved by miR-30a mimics transfection in hepatic stellate cells (HSCs) (HSC-T6, LX-2), and miR-30a agomir (ago-miR-30a) treatment in mice. MiR-30a levels were measured using TaqMan miRNA assay system, and the localization of miR-30a was detected by fluorescence in situ hybridization (FISH). The interaction of miR-30a and Beclin1 was confirmed by dual-luciferase reporter assay. Autophagic flux was analysed using tandem mRFP-GFP-LC3 fluorescence microscopy, electron microscopy and Western blot of LC3-II/I ratio. MiR-30a was notably down-regulated in activated HSCs and LX-2-exosomes induced by TGF-β1; overexpression of miR-30a down-regulated extracellular matrix (ECM), such as α-SMA, TIMP-1, and Collagen I expression, and suppressed cell viability in HSCs. MiR-30a was significantly down-regulated in hepatic fibrosis mice and overexpression of miR-30a prevented BDL-induced fibrogenesis, concomitant with the down-regulation of ECM. MiR-30a inhibited HSCs autophagy and increased lipid accumulation in HSCs and in mice fibrotic hepatic tissues. MiR-30a inhibited its downstream effector of Beclin1 by direct targeting its 3'-UTR region. Moreover, Knock-down of Beclin1 by small interfering RNA (siRNA) inhibited HSC autophagy and activation in LX-2 cells. In conclusion, miR-30a is down-regulated in hepatic fibrosis models and its overexpression prevents liver fibrogenesis by directly suppressing Beclin1-mediated autophagy; therefore, miR-30a may be a new potential therapeutic target for controlling hepatic fibrosis.