Isolation and characterization of a putative liver progenitor population after treatment of fetal rat hepatocytes with TGF-Beta

✍ Scribed by Gaelle del Castillo; Alberto Álvarez-Barrientos; Irene Carmona-Cuenca; Margarita Fernández; Aránzazu Sánchez; Isabel Fabregat

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 425 KB
• Volume: 215
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.21370

✦ Synopsis

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‐β) 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‐β‐treated fetal hepatocytes (TβT‐FH) and test whether they can behave as liver progenitors. The TβT‐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. TβT‐FH maintain expression of the hnf3β gene, but lose expression of hnf1β, 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. TβT‐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, TβT‐FH form duct‐like structures when cultured on Matrigel. TβT‐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‐β might play an essential role in the transdifferentiation process. J. Cell. Physiol. 215: 846–855, 2008. © 2008 Wiley‐Liss, Inc.