Smad7 inhibits collagen expression in human hepatic satellite cells in vitro

Objective To investigate the effect of Smad7 on the expressions of collagen I and α-smooth muscle actin(α-SMA) in HSC-T6 cell line activated by transforming growth factor-β1(TGF-β1).Methods HSC-T6 cells stably expressing M2-flag protein were selected after co-infection of the cells with pTRE-Smad7-M2-flag and pTet-on.The optimal dose of doxycycline for inducing Smad7 was determined,and the effects of Smad7 over-expression on the expressions of collagen I and α-SMA in the cells activated by TGF-β1 and on Smad2/3 phosphorylation were evaluated using Western blotting.Results The optimal dose of doxycycline for inducing Smad7 expression was 2 mg/L.Smad7 over-expression induced by doxycycline decreased the expressions of collagen I and α-SMA in HSC-T6 cells activated by TGF-β1,and down-regulated the level of Smad2/3 phosphorylation.Conclusion Smad7 over-expression inhibits Smad2/3 phosphorylation,and decreases the expression of collagen I and α-SMA in HSC-T6 cells induced by TGF-β1 to inhibit the progression of liver fibrosis.