Endothelin-1, a regulator of angiogenesis in the chick chorioallantoic membrane.
We investigated the angiogenic properties of endothelin-1 (ET-1) using a novel experimental approach involving the constant production and release of ET-1, which was achieved by grafting stably transfected Chinese hamster ovary (CHO) (CHO-ET-1) cell aggregates onto the chorioallantoic membrane (CAM) ectoderm. Macroscopic observation showed that CHO-ET-1 cell aggregates formed highly vascularized nodules surrounded by radially rearranged vessels, with a strong angiogenic response. 5-Bromo-2'-deoxy-uridine (BrdU) studies showed an increase in endothelial cell proliferation in the CAM vasculature around CHO-ET-1 nodules. An angiogenic response was also observed with gelatin sponges containing conditioned medium from CHO-ET-1 cells. The specific involvement of ET-1 in the angiogenic effect mediated by CHO-ET-1 was demonstrated by the reduction or abolition of neovascularized CHO-ET-1 nodules by (1) bosentan, a mixed antagonist of ET(A)/ET(B) receptors, (2) an ET(A) receptor antagonist (Ru69986) and (3) phosporamidon, an inhibitor of endothelin-converting enzyme-1 (ECE-1). We also demonstrated that VEGF was involved in CHO-ET-1-mediated angiogenesis, by using a specific inhibitor of VEGF tyrosine kinase receptor activity (PTK787/ZK 222584), which abolished CHO-ET-1 nodule formation and CAM neovascularization. Thus, our results show that exogenous ET-1 mediates angiogenesis in vivo.
Cruz
A
A
Collège de France and INSERM U36, Paris, France.
Parnot
C
C
Ribatti
D
D
Corvol
P
P
Gasc
J M
JM
D000482:Allantois / Q000098:blood supply*; D000818:Animals; D016466:CHO Cells; D002642:Chick Embryo; D002823:Chorion / Q000098:blood supply*; D006224:Cricetinae; D003470:Culture Media / Q000494:pharmacology; D046508:Culture Techniques; D019332:Endothelin-1 / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000196:embryology; D018919:Neovascularization, Physiologic / Q000187:drug effects*
D003470:Culture Media; D019332:Endothelin-1