The expression of epithelial-mesenchymal transition-related proteins in biliary epithelial cells is associated with liver fibrosis in biliary atresia.

BACKGROUND

The epithelial-mesenchymal transition (EMT) has been implicated as a key mechanism in the pathogenesis of liver fibrosis. The miR-200 family has been shown to inhibit EMT.

METHODS

Liver fibrosis levels were assessed with Masson's trichrome staining of liver samples obtained from biliary atresia (BA) patients. The expressions of cytokeratin-7 (CK-7) and α-smooth muscle actin (α-SMA) in the liver sections were detected by immunohistochemical and immunofluorescent staining. EMTs were induced by transforming growth factor (TGF)-β1 in human biliary epithelial cells (BECs) in vitro.

RESULTS

We showed that the EMT-related proteins CK-7 and α-SMA colocalized to the intrahepatic BECs in the liver sections of patients with BA. The level of α-SMA expression was related to liver fibrosis stage in BA. EMT in primary human intrahepatic BECs was induced by TGF-β1 in vitro. miR-200b is one member of the miR-200 family and significantly inhibited TGF-β1-mediated EMT in BECs.

CONCLUSION

Together, these data suggest that the occurrence of EMT in BECs might contribute to BA fibrosis. miR-200b significantly affects the development and progression of TGF-β1-dependent EMT and fibrosis in vitro.