Predominant role of endothelial nitric oxide synthase in vascular endothelial growth factor-induced angiogenesis and vascular permeability.
Nitric oxide (NO) plays a critical role in vascular endothelial growth factor (VEGF)-induced angiogenesis and vascular hyperpermeability. However, the relative contribution of different NO synthase (NOS) isoforms to these processes is not known. Here, we evaluated the relative contributions of endothelial and inducible NOS (eNOS and iNOS, respectively) to angiogenesis and permeability of VEGF-induced angiogenic vessels. The contribution of eNOS was assessed by using an eNOS-deficient mouse, and iNOS contribution was assessed by using a selective inhibitor [l-N(6)-(1-iminoethyl) lysine, l-NIL] and an iNOS-deficient mouse. Angiogenesis was induced by VEGF in type I collagen gels placed in the mouse cranial window. Angiogenesis, vessel diameter, blood flow rate, and vascular permeability were proportional to NO levels measured with microelectrodes: Wild-type (WT) > or = WT with l-NIL or iNOS(-/-) > eNOS(-/-) > or = eNOS(-/-) with l-NIL. The role of NOS in VEGF-induced acute vascular permeability increase in quiescent vessels also was determined by using eNOS- and iNOS-deficient mice. VEGF superfusion significantly increased permeability in both WT and iNOS(-/-) mice but not in eNOS(-/-) mice. These findings suggest that eNOS plays a predominant role in VEGF-induced angiogenesis and vascular permeability. Thus, selective modulation of eNOS activity is a promising strategy for altering angiogenesis and vascular permeability in vivo.
Edwin L. Steele Laboratory, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, 100 Blossom Street, Boston, MA 02114, USA. dai@steele.mgh.harvard.edu
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Fukumura
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Kadambi
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Izumi
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D000818:Animals; D001775:Blood Circulation / Q000502:physiology; D002199:Capillary Permeability / Q000502:physiology*; D016228:Endothelial Growth Factors / Q000502:physiology*; D005260:Female; D018398:Homeodomain Proteins / Q000235:genetics / Q000502:physiology; D008222:Lymphokines / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018919:Neovascularization, Physiologic / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000502:physiology*; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D018398:Homeodomain Proteins; D008222:Lymphokines; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; C064658:RAG-1 protein; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496317:Nos2 protein, mouse; C496315:Nos3 protein, mouse