TGFB1 and Hepatic fibrosis: Treating PCK cholangiocytes with transforming growth factor-β1 (TGF-β1), a potent inducer of EMT induces the expression of vimentin and fibronectin in vitro, indicating that PCK cholangiocytes acquire mesenchymal features in response to TGF-β1 and participate in progressive hepatic fibrosis by producing extracellular matrix molecules.