Differentiation of Human Embryonic Stem Cells into Functional Hepatocyte-Like Cells (Method)

Abstract

Hepatocytes derived from human embryonic stem cells (ESCs) are a potential cell source for regenerative medicine. However, the successful differentiation of human ESCs into mature hepatocytes has been difficult to achieve because the definitive mechanisms governing hepatocyte differentiation have not yet been well defined. The CD45−CD49f±Thy1+gp38+ mesenchymal cells that reside in murine fetal livers induce hepatic progenitor cells to differentiate into mature hepatocytes by direct cell-cell contact. A cell line named MLSgt20 was also successively established from these mesenchymal cells. These MLSgt20 cells possess the ability to promote the hepatic maturation of not only murine ESCs, but also human ESC-derived endodermal cells. To promote this maturation, human ESCs are treated with a two-step procedure for hepatic maturation; first, human ESCs are differentiated into endodermal cells, then human ESC-derived endodermal cells are matured into functional hepatocytes by co-culture with the MLSgt20 cells, thereby forming cell aggregates. These human ESC-derived hepatocyte-like cells possess hepatic functions.