miR-219-3p regulates the occurrence of hepatic fibrosis by targeting Smad2

Abnormal expression of microRNA (miR)-219-3p has been widely identified in different tumors. However, whether miR-219-3p is involved in the progression of hepatic fibrosis (HF) has never been explored. The present study showed that compared with healthy controls, the levels of miR-291-3p in peripheral blood were decreased in patients with HF. Furthermore, much lower levels of miR-291-3p were identified in fibrotic liver tissues compared with that of normal liver tissues. Receiver operating characteristic curve analysis showed that the levels of miR-291-3p in peripheral blood may screen patients with HF from healthy controls. Reverse transcription quantitative polymerase chain reaction analysis showed that overexpression of miR-291-3p significantly suppressed the mRNA levels of Snai1, vascular endothelial-specific cadherin (VE-cadherin), Vimentin, transforming growth factor (TGF)-β1, and glial fibrillary acidic protein (GFAP). The protein levels of Snai1, VE-cadherin, Vimentin, TGF-β1, and GFAP were also decreased in hepatic stellate cells transfected with miR-291-3p mimics. Further study indicated that mothers against decapentaplegic homolog 2 (Smad2) was a target gene of miR-291-3p. More importantly, silencing of Smad2 could abolish miR-291-3p inhibition-induced TGF-β1 signaling activation. In summary, reduced peripheral blood miR-291-3p may be involved in the progression of HF via targeting Smad2.