Differentiation of neonatal rat epithelial cells from biliary origin into immature hepatic cells by sequential exposure to hepatogenic cytokines and growth factors reflecting liver development.
It was investigated whether cryopreserved rat liver epithelial cells (RLEC) from biliary origin are capable of undergoing hepatic differentiation upon sequential exposure to liver-specific factors (fibroblast growth factor (FGF)-4, hepatocyte growth factor (HGF), insulin-transferrin-sodium-selenite (ITS), dexamethasone (Dex) and oncostatin M (OSM)), reflecting liver embryogenesis in vivo. As differentiation progressed, cells acquired a hepatic morphology (polygonal-to-cuboidal shaped, binucleated cells), corresponding well with the phenotypic changes observed. Biliary cytokeratin (CK)19 and connexin (Cx)43-expression both gradually decreased; CK19-expression disappeared even completely. In contrast, hepatic CK18-expression persisted throughout the culture time. Hepatocyte nuclear factor (HNF)3beta, alpha-foetoprotein (AFP), transthyretin (TTR), HNF4, albumin (ALB), HNF1alpha, multidrug resistance protein (MRP)2 and Cx32 were expressed at specific stages during RLEC-differentiation, thereby showing a progressive hepatic maturation. Indeed, immature AFP and mature ALB were sequentially expressed, in line with the in vivo liver embryogenesis. Expression of the early and mid-late 'liver-enriched' transcription factors (LETF) HNF3beta and HNF4 declined and translocated to the cytosol, respectively, while the late LETF HNF1alpha underwent a nuclear upregulation. In conclusion, RLEC are bipotent cells, capable of differentiation into immature hepatocytes in a hepatic-stimulating micro-environment. The robustness of the sequential conditions, developed before for hepatic 'transdifferentiation' of rat bone marrow stem cells (rBMSC), was hereby confirmed.
Snykers
Sarah
S
Department of Toxicology, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, B-1090 Brussels, Belgium. Sarah.Snykers@vub.ac.be
De Kock
Joery
J
Vanhaecke
Tamara
T
Rogiers
Vera
V
D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D018031:Connexin 43 / Q000235:genetics / Q000378:metabolism; D015925:Cryopreservation; D016207:Cytokines / Q000494:pharmacology*; D003907:Dexamethasone / Q000494:pharmacology; D004847:Epithelial Cells; D051519:Fibroblast Growth Factor 4 / Q000494:pharmacology; D005786:Gene Expression Regulation; D017228:Hepatocyte Growth Factor / Q000494:pharmacology; D022781:Hepatocytes / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology; D053539:Keratin-19 / Q000235:genetics / Q000378:metabolism; D053683:Oncostatin M / Q000494:pharmacology; D010641:Phenotype; D051381:Rats; D018038:Sodium Selenite / Q000494:pharmacology; D013997:Time Factors; D014168:Transferrin / Q000494:pharmacology
D018031:Connexin 43; D016207:Cytokines; D051519:Fibroblast Growth Factor 4; D007328:Insulin; D053539:Keratin-19; D014168:Transferrin; D053683:Oncostatin M; D017228:Hepatocyte Growth Factor; D003907:Dexamethasone; D018038:Sodium Selenite