Suppressive effect of microRNA-29b on hepatic stellate cell activation and its crosstalk with TGF-β1/Smad3.
The microRNA (miR)-29 family is closely associated with fibrotic processes by virtue of its low expression in many tissues during organ fibrosis. The present study investigated whether miR-29b overexpression suppressed hepatic stellate cell (HSC) activation and its interactions with transforming growth factor (TGF)-β1/mothers against decapentaplegic homolog 3 (Smad3), a classical signal transduction pathway contributing to the activation of HSCs. The results showed that transfection of LX-2 (human HSC) cells with miR-29b mimic or pSUPER-Smad3 silencing (si)RNA resulted in significantly increased expression of miR-29b and decreased expression of Smad3. miR-29b overexpression inhibited proliferation of LX-2 cells 24 h after transfection. Both miR-29b overexpression and Smad3 silencing antagonized the effects of TGF-β1 on the expression of α-smooth muscle actin (α-SMA) and collagen type I (col-1). Furthermore, infection with miR-29b mimics suppressed Smad3 and TGF-β1 expression, suggesting that miR-29b inhibited LX-2 activation mediated by both Smad3 and TGF-β1. Nevertheless, primary miR-29a/b1, miR-29b2/c and mature miR-29b were downregulated by TGF-β1 and stimulated by Smad3 silencing, suggesting that TGF-β1/Smad3 signalling pathway regulate not just mature miR-29b but also its transcription. In summary, our results show overwhelming evidence corroborating the suppressive effect of miR-29b on TGF-β1-induced LX-2 cell activation. The results also revealed the existence of crosstalk between miR-29b and TGF-β1/Smad3 during LX-2 activation, suggesting a feedback loop between miR-29b and TGF-β1/Smad3 signalling that promotes liver fibrosis. Copyright © 2016 The Authors. Cell Biochemistry and Function published by John Wiley & Sons, Ltd.
Department of Gastroenterology, Jinshan Hospital of Fudan University, Shanghai, China.
Chunli
C
Liang
Department of Gastroenterology, Jinshan Hospital of Fudan University, Shanghai, China.
Shurui
S
Bu
Department of Gastroenterology, Jinshan Hospital of Fudan University, Shanghai, China.
Xiaoming
X
Fan
D000199:Actins / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism; D005786:Gene Expression Regulation; D055166:Hepatic Stellate Cells / Q000166:cytology* / Q000378:metabolism*; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D051900:Smad3 Protein / Q000378:metabolism*; D014162:Transfection; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism*
C541116:ACTA2 protein, human; D000199:Actins; D024042:Collagen Type I; C532045:MIRN29a microRNA, human; D035683:MicroRNAs; D051900:Smad3 Protein; D053773:Transforming Growth Factor beta1
TGF-β1/Smad3; crosstalk; gene transfection; hepatic stellate cell; miR-29b