[Immortalization of endothelial cells differentiated from mouse embryonic stem cells]

This study is designed to immortalize endothelial cells differentiated from embryonic stem cells. The embryoid bodies (EB) formed in vitro from embryonic stem cells, were induced to differentiate into many "round cells" (the precursor of endothelial cells) by retinoic acid (RA) and transforming growth factor-beta1 (TGF-beta1). These "round cells" later formed the vascular tube-like structures. Studies by scanning electronic microscopy and light microscopy and immunocytochemistry, demonstrated that these tube-like structures were constituted by a large number of round and flat cells, which were positive for "vWF" and "CD34"staining. These results indicate they are vascular endothelial cells. To immortalize these cells, human telomerase reverse transcriptase (hTERT) cDNA was transfected into "round cells" by lipofectine. hTERT mRNA expression in transfected cells was confirmed by Dot blot, RT-PCR. Furthermore, 95% these transfected cells maintain the characteristic of endothelial cell, can proliferate in large quantity in vitro, and are able to form tubular structures. These results suggest that hTERT cDNA transfection can immortalize the induced endothelial cells and therefore may provide a new source of seed cells for vascular engineering.