MicroRNA-200a suppresses epithelial-to-mesenchymal transition in rat hepatic stellate cells via GLI family zinc finger 2

摘要

Hepatic stellate cells (HSCs) have an important role in liver fibrosis. Epithelial-to-mesenchymal transition (EMT), which is promoted by the Hedgehog (Hh) signaling pathway, is involved in the activation of HSCs. MicroRNAs (miRNAs/miRs) have been reported to be involved in the progression of liver fibrosis. A previous study indicated that the activation of HSCs was suppressed by miR-200a via targeting transforming growth factor-2 and -catenin. However, whether miR-200a is able to regulate the EMT in HSCs has remained elusive. The present study revealed that miR-200a was decreased in vitro and in vivo during liver fibrosis. Furthermore, miR-200a overexpression resulted in the inhibition of proliferation, -SMA expression and extracellular matrix production of activated HSCs. Of note, miR-200a overexpression reduced myofibroblastic markers, including -SMA, type I collagen and desmin, and increased the epithelial cell marker E-cadherin. These results were further confirmed by immunofluorescence staining. Further study showed that the expression of genes associated with Hh signaling, including Hhip, Shh and Gli1, were not affected by miR-200a. However, Gli2, a downstream signaling protein of the Hh pathway, was inhibited by miR-200a and confirmed as a target of miR-200a using a dual luciferase reporter assay. In addition, the inhibition of the Hh pathway by miR-200a resulted in an increase of BMP-7 and Id2 as well as a reduction of Snai1 and S100A4. Collectively, the results of the present study demonstrated that miR-200a suppressed the EMT process in HSCs, at least in part, via Gli2.