PERMISSIVE ROLE OF NITRIC-OXIDE IN ENDOTHELIN-INDUCED MIGRATION OF ENDOTHELIAL-CELLS

Endothelin (ET) synthesis is enhanced at sites of ischemia or in injur ed vessels. The purpose of this study was to explore the possibility o f autocrine stimulation of endothelial cell migration by members of th e endothelin family. Experiments with microvascular endothelial cell t ransmigration in a Boyden chemotactic apparatus showed that endothelin s 1 and 3, as well as a selective agonist of ET(B) receptor IRL-1620, equipotently stimulated migration. Endothelial cell migration was unaf fected by the blockade of ET(A) receptor, but it was inhibited by ET(B ) receptor antagonism. Based on our previous demonstration of signalin g from the occupied ET(B) receptor to constitutive nitric oxide (NO) s ynthase (Tsukahara, H., Ende, H., Magazine, H. I., Bahou, W. F., and G oligorsky, M. S. (1994) J. Biol. Chem. 269, 21778-21785), we next exam ined the contribution of ET-stimulated NO production to endothelial ce ll migration. In three independent cellular systems, 1) migration and wound healing by microvascular endothelial cells, 2) wound healing by Chinese hamster ovary cells stably expressing ET(B) receptor with or w ithout endothelial NO synthase, and 3) application of antisense oligod eoxynucleotides targeting endothelial NO synthase in human umbilical v ein endothelial cells, an absolute requirement for the functional NO s ynthase in cell migration has been demonstrated. These findings establ ish the permissive role of NO synthesis in endothelin stimulated migra tion of en dothelial cells.