title: Vascular endothelial growth factor (VEGF)-D and VEGF-A differentially regulate KDR-mediated signaling and biological function in vascular endothelial cells.
abstract: Vascular endothelial growth factor (VEGF)-D binds to VEGF receptors (VEGFR) VEGFR2/KDR and VEGFR3/Flt4, but the signaling mechanisms mediating its biological activities in endothelial cells are poorly understood. Here we investigated the mechanism of action of VEGF-D, and we compared the signaling pathways and biological responses induced by VEGF-D and VEGF-A in endothelial cells. VEGF-D induced KDR and phospholipase C-gamma tyrosine phosphorylation more slowly and less effectively than VEGF-A at early times but had a more sustained effect and was as effective as VEGF-A after 60 min. VEGF-D activated extracellular signal-regulated protein kinases 1 and 2 with similar efficacy but slower kinetics compared with VEGF-A, and this effect was blocked by inhibitors of protein kinase C and mitogen-activated protein kinase kinase. In contrast to VEGF-A, VEGF-D weakly stimulated prostacyclin production and gene expression, had little effect on cell proliferation, and stimulated a smaller and more transient increase in intracellular [Ca(2+)]. VEGF-D induced strong but more transient phosphatidylinositol 3-kinase (PI3K)-mediated Akt activation and increased PI3K-dependent endothelial nitric-oxide synthase phosphorylation and cell survival more weakly. VEGF-D stimulated chemotaxis via a PI3K/Akt- and endothelial nitric-oxide synthase-dependent pathway, enhanced protein kinase C- and PI3K-dependent endothelial tubulogenesis, and stimulated angiogenesis in a mouse sponge implant model less effectively than VEGF-A. VEGF-D-induced signaling and biological effects were blocked by the KDR inhibitor SU5614. The finding that differential KDR activation by VEGF-A and VEGF-D has distinct consequences for endothelial signaling and function has important implications for understanding how multiple ligands for the same VEGF receptors can generate ligand-specific biological responses.
authors.affiliation: Department of Medicine, The Rayne Institute, University College London, 5 University Street, London WC1E 6JJ, UK.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Jia
authors.forename: Azadeh
authors.initials: A
authors.lastname: Bagherzadeh
authors.forename: Roy
authors.initials: R
authors.lastname: Bicknell
authors.forename: Michael R
authors.initials: MR
authors.lastname: Duchen
authors.forename: Dan
authors.initials: D
authors.lastname: Liu
authors.forename: Ian
authors.initials: I
authors.lastname: Zachary
mesh_terms: D000818:Animals; D004730:Endothelium, Vascular / Q000502:physiology*; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D051379:Mice; D018919:Neovascularization, Physiologic / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology / Q000502:physiology*; D042643:Vascular Endothelial Growth Factor D / Q000494:pharmacology / Q000502:physiology*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: D007211:Indoles; C416849:SU 5614; D042461:Vascular Endothelial Growth Factor A; D042643:Vascular Endothelial Growth Factor D; D040301:Vascular Endothelial Growth Factor Receptor-2