Embryonic Stem Cell-Derived Endothelial Cells

Embryonic stem (ES) cells established from the inner cell mass of blastocysts possess pluripotent differentiation potential and unlimited self-renewal capacity. Thus, ES cells serve as a promising cell source for regenerative medicine. Another indispensable role of ES cells is its potency to dissect differentiation processes of mammalian cells in vitro. Until now, embyroid bodies, which form as aggregates of ES cells, are often used to induce various cell types including endothelial cells, neural cells, cardiomyocytes, and blood cells (Rathjen et al. 2001) (see Outline). Though the embryoid body method is convenient for inducing differentiation, it has several limitations in dissecting cellular and molecular mechanisms during differentiation such as: i) Difficulty to dissect the differentiation mechanisms by highlighting cells and signals of interest among the complicated cellular interactions in embryoid bodies; ii) Difficulty to directly observe differentiating cells at the cellular level by microscopy; iii) Inability to conduct single cell analysis of differentiation; iv) Difficulty in dissociating cell aggregates and obtaining single cell suspensions of induced cells. To overcome these difficulties in embryoid body cultures,we developed a novel ES cell differentiation system employing 2-dimensional culture conditions.