title: Role of epimorphin in bile duct formation of rat liver epithelial stem-like cells: involvement of small G protein RhoA and C/EBPβ.
abstract: Epimorphin/syntaxin 2 is a high conserved and very abundant protein involved in epithelial morphogenesis in various organs. We have shown recently that epimorphin (EPM), a protein exclusively expressed on the surface of hepatic stellate cells and myofibroblasts of the liver, induces bile duct formation of hepatic stem-like cells (WB-F344 cells) in a putative biophysical way. Therefore, the aim of this study was to present some of the molecular mechanisms by which EPM mediates bile duct formation. We established a biliary differentiation model by co-culture of EPM-overexpressed mesenchymal cells (PT67(EPM)) with WB-F344 cells. Here, we showed that EPM could promote WB-F344 cells differentiation into bile duct-like structures. Biliary differentiation markers were also elevated by EPM including Yp, Cx43, aquaporin-1, CK19, and gamma glutamyl transpeptidase (GGT). Moreover, the signaling pathway of EPM was analyzed by focal adhesion kinase (FAK), extracellular regulated kinase 1/2 (ERK1/2), and RhoA Western blot. Also, a dominant negative (DN) RhoA-WB-F344 cell line (WB(RhoA-DN)) was constructed. We found that the levels of phosphorylation (p) of FAK and ERK1/2 were up-regulated by EPM. Most importantly, we also showed that RhoA is necessary for EPM-induced activation of FAK and ERK1/2 and bile duct formation. In addition, a dual luciferase-reporter assay and CHIP assay was performed to reveal that EPM regulates GGT IV and GGT V expression differentially, possibly mediated by C/EBPβ. Taken together, these data demonstrated that EPM regulates bile duct formation of WB-F344 cells through effects on RhoA and C/EBPβ, implicating a dual aspect of this morphoregulator in bile duct epithelial morphogenesis.
authors.affiliation: Stem Cell and Regenerative Medicine Lab, Beijing Institute of Transfusion Medicine, Beijing, China.
authors.forename: Yali
authors.initials: Y
authors.lastname: Jia
authors.forename: Hailei
authors.initials: H
authors.lastname: Yao
authors.forename: Junnian
authors.initials: J
authors.lastname: Zhou
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.forename: Quan
authors.initials: Q
authors.lastname: Zeng
authors.forename: Hongfeng
authors.initials: H
authors.lastname: Yuan
authors.forename: Lei
authors.initials: L
authors.lastname: Shi
authors.forename: Xue
authors.initials: X
authors.lastname: Nan
authors.forename: Yunfang
authors.initials: Y
authors.lastname: Wang
authors.forename: Wen
authors.initials: W
authors.lastname: Yue
authors.forename: Xuetao
authors.initials: X
authors.lastname: Pei
mesh_terms: D000818:Animals; D051398:Aquaporin 1 / Q000378:metabolism; D001652:Bile Ducts / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D018920:Coculture Techniques; D018031:Connexin 43 / Q000378:metabolism; D051549:Glutathione S-Transferase pi / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D015854:Up-Regulation; D005723:gamma-Glutamyltransferase / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: C496022:Aqp1 protein, rat; D022782:CCAAT-Enhancer-Binding Protein-beta; C545014:Cebpb protein, rat; D018031:Connexin 43; D008562:Membrane Glycoproteins; C504581:Stx2 protein, rat; D051398:Aquaporin 1; D005723:gamma-Glutamyltransferase; D051549:Glutathione S-Transferase pi; D011494:Protein Kinases; D020742:rhoA GTP-Binding Protein