Vascular Endothelial Growth Factor Increases Endothelial Nitric Oxide Synthase Transcription In Huvec Cells

Although it is known that VEGF increases eNOS protein, the mechanisms responsible remain unclear. To determine if VEGF alters eNOS transcription, human umbilical vein endothelial cells were transfected with reporters under the control of the eNOS promoter and stimulated with VEGF₁₆₅. VEGF significantly increased eNOS-mRNA after 2 hours exposure. VEGF significantly increased eNOS reporter activity as early as one hour (268±32%), but this increase returned to baseline after 6 hours. Using deletion constructs, the VEGF response region was initially localized to within the -722/-494 region. GMSA indicated that VEGF increased DNA binding to both a cAMP-like and AP1-like response elements. Site-specific mutations and heterologous constructs indicated that the site centered at AP1-like site was both necessary and sufficient to meditate VEGF transcriptional activation. These results indicate that VEGF rapidly activates eNOS transcription prior to a rise eNOS-mRNA, an effect mediated by a cis-trans interaction localized to an AP1-like site within the eNOS promoter.