The liver is the largest internal organ and it provides many essential metabolic, exocrine and endocrine functions. Hepatocytes are the principal cell type in the liver and these along with biliary epithelial cells are derived from the embryonic endoderm. Embryological experiments in animal models have demonstrated that liver development occurs through a progressive series of reciprocal tissue interactions between the embryonic endoderm and nearby mesoderm. In the last ten years many of the genes and molecular pathways that regulate hepatogenesis have been identified. Recently application of this knowledge has enabled researchers to produce “hepatic-like” tissue from embryonic stem (ES) cells in vitro, which may ultimately lead to therapeutically useful tissue for transplantation. This review summarizes the current understanding of the molecular pathways controlling liver and biliary system development focusing on studies in the mouse embryo where this process is best understood.
Copyright: © 2008 Aaron M. Zorn.