title: Isolation and characterization of a putative liver progenitor population after treatment of fetal rat hepatocytes with TGF-beta.
abstract: The "in vitro" establishment of a physiological model of bipotential liver progenitors would be useful for analyzing the molecular mechanisms involved in regulating growth and differentiation, as well as studying their potential role/s in liver physiology and pathology. The transforming growth factor-beta (TGF-beta) induces de-differentiation of fetal rat hepatocytes (FH), concomitant with changes in morphology. The aim of this work was to isolate and characterize this population of TGF-beta-treated fetal hepatocytes (TbetaT-FH) and test whether they can behave as liver progenitors. The TbetaT-FH isolated cell lines show high expression of Thy-1 and low expression of c-Kit. They express liver-specific proteins, such as albumin and alpha-fetoprotein, and mesenchymal markers, such as vimentin. TbetaT-FH maintain expression of the hnf3beta gene, but lose expression of hnf1beta, hnf4, and hnf6. They express c-met and show an increase in proliferation in response to HGF. Interestingly, the transdifferentiation process is coincident with changes in the expression of genes related to the oxidative metabolism. TbetaT-FH cultured in the presence of EGF + DMSO change morphology, towards epithelial cells, gaining expression of CK19 and c-Kit, markers found in hepatoblasts and bile duct cells. Furthermore, TbetaT-FH form duct-like structures when cultured on Matrigel. TbetaT-FH show also potential to revert to an hepatocyte phenotype when submitted to a long-term "in vitro" differentiation protocol towards hepatocytic lineage. In summary, our results support the hypothesis that hepatocytes can function as facultative liver stem cells and demonstrate that TGF-beta might play an essential role in the transdifferentiation process.
authors.affiliation: Departamento de Bioquímica y Biología Molecular II, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Gaelle
authors.initials: G
authors.lastname: del Castillo
authors.forename: Alberto
authors.initials: A
authors.lastname: Alvarez-Barrientos
authors.forename: Irene
authors.initials: I
authors.lastname: Carmona-Cuenca
authors.forename: Margarita
authors.initials: M
authors.lastname: Fernández
authors.forename: Aránzazu
authors.initials: A
authors.lastname: Sánchez
authors.forename: Isabel
authors.initials: I
authors.lastname: Fabregat
mesh_terms: D000418:Albumins / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D019070:Cell Lineage / Q000187:drug effects; D002469:Cell Separation; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D005333:Fetus / Q000166:cytology* / Q000187:drug effects*; D022781:Hepatocytes / Q000166:cytology* / Q000187:drug effects*; D006801:Humans; D008099:Liver / Q000166:cytology* / Q000187:drug effects; D010641:Phenotype; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
chemical_list: D000418:Albumins; D017382:Reactive Oxygen Species; D016212:Transforming Growth Factor beta; D004121:Dimethyl Sulfoxide