title: Vascular endothelial growth factor receptor-1 modulates vascular endothelial growth factor-mediated angiogenesis via nitric oxide.
abstract: The known responses of vascular endothelial growth factor (VEGF) are mediated through VEGF receptor-2 (VEGFR-2/KDR) in endothelial cells. However, it is unknown whether VEGFR-1 (Flt-1) is an inert decoy or a signaling receptor for VEGF during physiological or pathological angiogenesis. Here we report that VEGF-stimulated nitric oxide (NO) release is inhibited by blockade of VEGFR-1 and that VEGFR-1 via NO negatively regulates of VEGFR-2-mediated proliferation and promotes formation of capillary networks in human umbilical vein endothelial cells (HUVECs). Inhibition of VEGFR-1 in a murine Matrigel angiogenesis assay induced large aneurysm-like structures. VEGF-induced capillary growth over 14 days was inhibited by anti-VEGFR-2-blocking antibody as determined by reduced tube length between capillary connections (P < 0.0001) in an in vitro angiogenesis assay. In contrast, loss of VEGFR-1 activity with a neutralizing anti-VEGFR-1 antibody resulted in an increase in the accumulation of endothelial cells (P < 0.0001) and a dramatic decrease in the number of capillary connections that were restored by the addition of NO donor. Porcine aortic endothelial (PAE) cells expressing human VEGFR-1 but not VEGFR-2 plated on growth factor-reduced Matrigel rearranged into tube-like structures that were prevented by anti-VEGFR-1 antibody or a cGMP inhibitor. VEGF stimulated NO release from VEGFR-1- but not VEGFR-2-transfected endothelial cells and placenta growth factor-1 stimulated NO release in HUVECs. Blockade of VEGFR-1 increased VEGF-mediated HUVEC proliferation that was inhibited by NO donors, and potentiated by NO synthase inhibitors. These data indicate that VEGFR-1 is a signaling receptor that promotes endothelial cell differentiation into vascular tubes, in part by limiting VEGFR-2-mediated endothelial cell proliferation via NO, which seems to be a molecular switch for endothelial cell differentiation.
authors.affiliation: Department of Reproductive and Vascular Biology, The Medical School, University of Birmingham, Edgbaston, Birmingham, United Kingdom.
authors.forename: B
authors.initials: B
authors.lastname: Bussolati
authors.forename: C
authors.initials: C
authors.lastname: Dunk
authors.forename: M
authors.initials: M
authors.lastname: Grohman
authors.forename: C D
authors.initials: CD
authors.lastname: Kontos
authors.forename: J
authors.initials: J
authors.lastname: Mason
authors.forename: A
authors.initials: A
authors.lastname: Ahmed
mesh_terms: D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D016228:Endothelial Growth Factors / Q000494:pharmacology / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology*; D006801:Humans; D008222:Lymphokines / Q000494:pharmacology / Q000502:physiology*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D009603:Nitroso Compounds / Q000494:pharmacology; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D020033:Protein Isoforms / Q000276:immunology; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D020794:Receptor Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D017978:Receptors, Growth Factor / Q000235:genetics / Q000502:physiology; D040262:Receptors, Vascular Endothelial Growth Factor; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D042442:Vascular Endothelial Growth Factors
chemical_list: D016228:Endothelial Growth Factors; D008222:Lymphokines; C436287:N-glucopyranosyl-N2-acetyl-S-nitrosopenicillaminamide; D020030:Nitric Oxide Donors; D009603:Nitroso Compounds; D020033:Protein Isoforms; D011518:Proto-Oncogene Proteins; D017978:Receptors, Growth Factor; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D009569:Nitric Oxide; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor; D040281:Vascular Endothelial Growth Factor Receptor-1; D010396:Penicillamine