Ligustrazine Attenuates Liver Fibrosis by Targeting miR-145 Mediated Transforming Growth Factor-β/Smad Signaling in an Animal Model of Biliary Atresia

To investigate therapeutic target for ligustrazine during liver fibrosis in an ethanol-induced biliary atresia rat model and transforming growth factor-β (TGF-β) induced hepatic stellate cell activation cell model, and the underlying mechanism, a total of 30 rats were randomly assigned into five groups (n = 6 per group): control, sham, ethanol-induced biliary atresia model, model plus pirfenidone, and model plus ligustrazine groups. The liver changes were assessed using H&E and Masson staining and transmission electron microscopy. Expression of miR-145 and mRNA and protein levels of TGF-β/smads pathway-related proteins were detected. HSC-T6 cells were infected with LV-miR or rLV-miR-145 in the presence or absence of SMAD3 inhibitor SIS3 and treated with 2.5 ng/ml TGF-β1 and then with ligustrazine. Collected cells were subjected to detect the expression of miR-145 and mRNA and protein expression levels of TGF-β/smads pathway–related proteins. Ligustrazine rescued liver fibrogenesis and pathology for ethanol-caused bile duct injury, revealed by decreased α-smooth muscle actin and collagen I expression and liver tissue and cell morphology integrity. Further experiments showed that ligustrazine inhibited intrinsic and phosphorylated Smad2/3 protein expression and modification. Similar results were obtained in cells. In addition, ligustrazine altered miR-145 expression in both animal and cell models. Lentivirus mediated miR-145 overexpression and knockdown recombinant virus showed that miR-145 enhanced the TGF-β/Smad pathway, which led to hepatic stellate cell activation, and ligustrazine blocked this activation. This work validated that ligustrazine-regulated miR-145 mediated TGF-β/Smad signaling to inhibit the progression of liver fibrosis in a biliary atresia rat model and provided a new therapeutic strategy for liver fibrosis.

SIGNIFICANCE STATEMENT

With an ethanol-induced biliary atresia rat model, ligustrazine was found to rescue liver fibrogenesis and pathology for ethanol caused bile duct injury, revealed by decreased α-smooth muscle actin and collagen I expression and liver tissue and cell morphology integrity. Furthermore, we found ligustrazine upregulated miR-145 expression and inhibited TGF-β/SMAD signaling pathway both in vivo and in vitro. In addition, overexpression and knockdown of miR-145 confirmed that miR-145 is involved in the ligustrazine inhibition of liver fibrosis through the TGF-β/SMAD signaling pathway.