Defective angiogenesis in mice lacking endoglin

Endoglin is a transforming growth factor-beta (TCF-beta) binding protein ex pressed on the surface of endothelial cells. Loss-of-function mutations in the human endoglin gene ENG cause hereditary hemorrhagic telangiectasia (HH T1), a disease characterized by vascular malformations. Here it is shown th at by gestational day 11.5, mice lacking endoglin die from defective vascul ar development. However, in contrast to mice lacking TGF-beta, vasculogenes is was unaffected. Loss of endoglin caused poor vascular smooth muscle deve lopment and arrested endothelial remodeling. These results demonstrate that endoglin is essential for angiogenesis and suggest a pathogenic mechanism for HHT1.