Nitric oxide production contributes to the angiogenic properties of vascular endothelial growth factor in human endothelial cells.
Vascular endothelial growth factor (VEGF) is a regulator of vasculogenesis and angiogenesis. To investigate the role of nitric oxide (NO) in VEGF-induced proliferation and in vitro angiogenesis, human umbilical vein endothelial cells (HUVEC) were used. VEGF stimulated the growth of HUVEC in an NO-dependent manner. In addition, VEGF promoted the NO-dependent formation of network-like structures in HUVEC cultured in three dimensional (3D) collagen gels. Exposure of cells to VEGF led to a concentration-dependent increase in cGMP levels, an indicator of NO production, that was inhibited by nitro-L-arginine methyl ester. VEGF-stimulated NO production required activation of tyrosine kinases and increases in intracellular calcium, since tyrosine kinase inhibitors and calcium chelators attenuated VEGF-induced NO release. Moreover, two chemically distinct phosphoinositide 3 kinase (PI-3K) inhibitors attenuated NO release after VEGF stimulation. In addition, HUVEC incubated with VEGF for 24 h showed an increase in the amount of endothelial NO synthase (eNOS) protein and the release of NO. In summary, both short- and long-term exposure of human EC to VEGF stimulates the release of biologically active NO. While long-term exposure increases eNOS protein levels, short-term stimulation with VEGF promotes NO release through mechanisms involving tyrosine and PI-3K kinases, suggesting that NO mediates aspects of VEGF signaling required for EC proliferation and organization in vitro.
Papapetropoulos
A
A
Department of Pharmacology and Molecular Cardiobiology Division, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536-0812, USA.
García-Cardeña
G
G
Madri
J A
JA
Sessa
W C
WC
D000818:Animals; D002455:Cell Division; D002478:Cells, Cultured; D016228:Endothelial Growth Factors / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology* / Q000378:metabolism; D006801:Humans; D008222:Lymphokines / Q000502:physiology*; D018919:Neovascularization, Physiologic; D009569:Nitric Oxide / Q000096:biosynthesis / Q000502:physiology*; D051381:Rats; D015398:Signal Transduction; D013997:Time Factors; D014471:Umbilical Veins / Q000166:cytology; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D009569:Nitric Oxide