VEGF-A induces expression of eNOS and iNOS in endothelial cells via VEGF receptor-2 (KDR).
Vascular Endothelial Growth Factor-A (VEGF-A) is an endothelial-specific growth factor that induces angiogenesis, i.e., sprouting of capillaries from preexisting vessels in vivo. Endothelial nitric oxide synthase (eNOS) is an essential molecule in mediating VEGF-A-induced angiogenesis and endothelial function via production of nitric oxide (NO). Moreover, the protein level of eNOS is upregulated in response to VEGF-A. While VEGF-A-induced NO release in human trophoblast cells appears to be initiated via VEGF receptor-1, it is not clear which of the VEGF-receptors is mediating the signal for induction of eNOS protein expression. In addition, it is unclear whether other NOS isoforms are upregulated in response to VEGF-A stimulation. To address these questions, we stimulated human umbilical vein endothelial cells (HUVEC) with VEGF-A for 24 hours and evaluated expression of eNOS and iNOS protein. VEGF-A induces expression of both members of the NOS family. Using porcine aortic endothelial cells overexpressing either VEGF receptor-2 (PAE/KDR cells) or VEGF receptor-1 (PAE/Flt-1 cells), we have studied the regulation of iNOS and eNOS expression in response to VEGF-A stimulation. The activation of VEGF receptor-2 leads to an upregulation of both eNOS and iNOS protein, while stimulation of VEGF receptor-1 did not generate such a signal. Therefore, only VEGF receptor-2 mediates stimulation of eNOS and iNOS expression. We conclude that the two VEGF receptors have different and distinct functions regarding NO formation and NO release during VEGF-A-induced angiogenesis.
Kroll
J
J
Department of Internal Medicine II (Cardiology), Ulm University Medical Center, Ulm, Germany.
Waltenberger
J
J
D000818:Animals; D002478:Cells, Cultured; D016228:Endothelial Growth Factors / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology*; D004790:Enzyme Induction; D006801:Humans; D008222:Lymphokines / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D017978:Receptors, Growth Factor / Q000378:metabolism*; D040262:Receptors, Vascular Endothelial Growth Factor; D013552:Swine; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D011518:Proto-Oncogene Proteins; D017978:Receptors, Growth Factor; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; C496319:NOS2 protein, human; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor; D040281:Vascular Endothelial Growth Factor Receptor-1