MicroRNA­200a suppresses epithelial­to­mesenchymal transition in rat hepatic stellate cells via GLI family zinc finger 2.

ABSTRACT

Hepatic stellate cells (HSCs) have an important role in liver fibrosis. Epithelial­to­mesenchymal 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 miR­200a via targeting transforming growth factor­ß2 and ß­catenin. However, whether miR­200a is able to regulate the EMT in HSCs has remained elusive. The present study revealed that miR­200a was decreased in vitro and in vivo during liver fibrosis. Furthermore, miR­200a overexpression resulted in the inhibition of proliferation, α­SMA expression and extracellular matrix production of activated HSCs. Of note, miR­200a overexpression reduced myofibroblastic markers, including α­SMA, type I collagen and desmin, and increased the epithelial cell marker E­cadherin. 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 miR­200a. However, Gli2, a downstream signaling protein of the Hh pathway, was inhibited by miR­200a and confirmed as a target of miR­200a using a dual luciferase reporter assay. In addition, the inhibition of the Hh pathway by miR­200a resulted in an increase of BMP­7 and Id2 as well as a reduction of Snai1 and S100A4. Collectively, the results of the present study demonstrated that miR­200a suppressed the EMT process in HSCs, at least in part, via Gli2.