Abstract
Nitric oxide (NO) seems to play a pivotal role in the vascular endothelial growth factor (VEGF)-induced endothelial cell proliferation. This study was designed to
investigate the role and intracellular signal pathway of endothelial nitric oxide
synthase (eNOS) activation induced by VEGF. ECV 304 cells were treated with
betaVEGF(165) and then cell proliferation, eNOS protein and mRNA expression levels
were analyzed to elucidate the functional role of eNOS in cell proliferation induced
by VEGF. After exposure of cells to betaVEGF(165) , eNOS activity and cell growth were
increased by approximately two-fold in the betaVEGF(165) -treated cells compared to
the untreated cells. In addition, VEGF stimulated eNOS expression at both the
mRNA and protein levels in a dose-dependent manner. Phosphatidylinositol-3
kinase (PI-3K) inhibitors were used to assess PI-3K involvement in eNOS regulation.
LY294002 was found to attenuate VEGF-stimulated eNOS expression.
Wortmannin was not as effective as LY294002, but the reduction effect was detectable.
Cells activated by VEGF showed increased ERK1/2 levels. Moreover,
the VEGF-induced eNOS expression was reduced by the PD98059, MAPK pathway
inhibitor. This suggests that eNOS expression might be regulated by PI-3K
and the ERK1/2 signaling pathway. In conclusion, betaVEGF(165) induces ECV 304 cell
proliferation via the NO produced by eNOS. In addition, eNOS may be regulated
by the PI-3K or mitogen-activated protein kinase pathway.