Susceptibility of chimeric mice with livers repopulated by serially subcultured human hepatocytes to hepatitis B virus.
We previously identified a small population of replicative hepatocytes in long-term cultures of human adult parenchymal hepatocytes (PHs) at a frequency of 0.01%-0.09%. These hepatocytes were able to grow continuously through serial subcultures as colony-forming parenchymal hepatocytes (CFPHs). In the present study, we generated gene expression profiles for cultured CFPHs and found that they expressed cytokeratin 19, CD90 (Thy-1), and CD44, but not mature hepatocyte markers such as tryptophan-2,3-dioxygenase (TO) and glucose-6-phosphatase (G6P), confirming that these cells are hepatic progenitor-like cells. The cultured CFPHs were resistant to infection with human hepatitis B virus (HBV). To examine the growth and differentiation capacity of the cells in vivo, serially subcultured CFPHs were transplanted into the progeny of a cross between albumin promoter/enhancer-driven urokinase plasminogen activator-transgenic mice and severe combined immunodeficient (SCID) mice. The cells were engrafted into the liver and were able to grow for at least 10 weeks, ultimately reaching a maximum occupancy rate of 27%. The CFPHs in the host liver expressed differentiation markers such as TO, G6P, and cytochrome P450 subtypes and could be infected with HBV. CFPH-chimeric mice with a relatively high replacement rate exhibited viremia and had high serum levels of hepatitis B surface antigen.


CONCLUSIONS
Serially subcultured human hepatic progenitor-like cells from postnatal livers successfully repopulated injured livers and exhibited several phenotypes of mature hepatocytes, including susceptibility to HBV. In vitro-expanded CFPHs can be used to characterize the differentiation state of human hepatic progenitor-like cells.
D000293:Adolescent; D000818:Animals; D002478:Cells, Cultured; D002648:Child; D003114:Colony-Forming Units Assay; D015925:Cryopreservation; D005260:Female; D020869:Gene Expression Profiling; D006515:Hepatitis B virus; D022781:Hepatocytes / Q000166:cytology / Q000502:physiology* / Q000637:transplantation* / Q000821:virology; D006801:Humans; D007223:Infant; D008297:Male; D051379:Mice; D016513:Mice, SCID; D008822:Mice, Transgenic; D018183:Transplantation Chimera