Characterization and hepatic differentiation of skin-derived precursors from adult foreskin by sequential exposure to hepatogenic cytokines and growth factors reflecting liver development.

In the present study, we investigated whether precursor cells isolated from the dermis of infant human foreskin are capable to differentiate into hepatocyte-like cells upon sequential and gradual exposure to hepatogenic factors [fibroblast growth factor (FGF)-4, hepatocyte growth factor (HGF), insulin-transferrin-selenite (ITS), dexamethasone and oncostatin M (OSM)], mimicking the liver embryogenesis in vivo. Undifferentiated human skin-derived precursors (hSKP) are characterized by a fibroblast-like shape. Yet, they already express typical hepatic proteins, including cytokeratin (CK)-18, hepatocyte nuclear factor (HNF)-4 and HNF-1alpha. Microarray analysis further reveals gene expression of (i) the stemness markers nestin, POU5F1 (OCT-4), telomerase reverse transcriptase (TERT) and thymocyte differentiation antigen (THY)-1, (ii) biliary CK14 and CK19, (iii) biliary/foetal hepatic connexin (Cx)-43, and (iv) adult hepatic CK18, HNF-4 and HNF-1alpha. Upon differentiation, cells undergo morphological and phenotypic changes. As such, hSKP adopt a more polygonal-to-cuboidal cell shape. At the protein level, Cx43 expression is downregulated whereas typical hepatic markers, including alfa-foetoprotein (AFP), prealbumin (TTR) and albumin (ALB), become expressed in accordance to in vivo patterns observed during hepatogenesis. In conclusion, these data show for the first time that hSKP are capable to "trans" differentiate into hepatocyte-like cells upon mimicking the in vivo micro-environment of developing hepatocytes in vitro.