miRNA-338-3p/CDK4 signaling pathway suppressed hepatic stellate cell activation and proliferation

BACKGROUND Activated hepatic stellate cell (HSC) is the main fibrogenic cell type in the injured liver. miRNA plays an important role in activation and proliferation of HSC. METHODS Our previous study examined the expression profiles of microRNAs in quiescent and activated HSC. Real-time PCR and western blot were used to detect the expression of Collagen type I (Col 1) and Alpha-Smooth Muscle Actin (α-SMA). CCK-8 and Edu assay was used to measure the proliferation rate of HSC. Luciferase reporter gene assay was used to tested the binding between miR-338-3p and Cyclin-dependent kinase 4 (CDK4). RESULTS We found overexpression of miR-338-3p could inhibit Col 1 and α-SMA, two major HSC activation markers, whereas miR-338-3p inhibitor could promote them. Besides, miR-338-3p overexpression could suppress the growth rate of HSC. Further, we found that CDK4, a pleiotropic signaling protein, was a direct target gene of miR-338-3p. Moreover, we found that overexpression of CDK4 could block the effects of miR-338-3p. CONCLUSIONS We found miR-338-3p is an anti-fibrotic miRNA which inhibits cell activation and proliferation. Our findings suggest that miR-338-3p/CDK4 signaling pathway participates in the regulation of HSC activation and growth and may act as a novel target for further anti-fibrotic therapy.