Hepatoblast-like progenitor cells derived from embryonic stem cells can repopulate livers of mice.

Background & Aims: Hepatocyte-like cells can be derived from pluripotent stem cells such as embryonic stem (ES) cells, but ES cell-derived hepatic cells with extensive capacity to repopulate liver have not been identified. We aimed to identify and purify ES cell-derived hepatoblast-like progenitor cells and to explore their capacity for liver repopulation in mice after in vitro expansion.

Methods: Unmanipulated mouse ES cells were cultured under defined conditions and allowed to undergo stepwise hepatic differentiation. The derived hepatic cells were examined by morphologic, fluorescence-activated cell sorting, gene expression, and clonal expansion analyses. The capacities of ES cell-derived hepatic progenitor cells to repopulate liver were investigated in mice that were deficient in fumarylacetoacetate hydrolase (Fah) (a model of liver injury).

Results: Mouse ES cells were induced to differentiate into a population that contained hepatic progenitor cells; this population included cells that expressed epithelial cell adhesion molecule (EpCAM) but did not express c-Kit. Clonal hepatic progenitors that arose from single c-Kit(-)EpCAM(+) cells could undergo long-term expansion and maintain hepatoblast-like characteristics. Enriched c-Kit(-)EpCAM(+) cells and clonally expanded hepatic progenitor cells repopulated the livers of Fah-deficient mice without inducing tumorigenesis.

Conclusions: ES cell-derived c-Kit(-)EpCAM(+) cells contain a population of hepatoblast-like progenitor cells that can repopulate livers of mice.