Important role of Nox4 type NADPH oxidase in angiogenic responses in human microvascular endothelial cells in vitro.
OBJECTIVE
Redox signaling mediated by Nox2-containing NADPH oxidase has been implicated in angiogenic responses both in vitro and in vivo. Because Nox4 type NADPH oxidase is also highly expressed in endothelial cells, we studied the role of Nox4 in angiogenic responses in human endothelial cells in culture.


RESULTS
Inhibition of Nox4 expression by small interfering RNA reduced angiogenic responses as assessed by the tube formation and wound healing assays, in both human microvascular and umbilical vein endothelial cells. Overexpression of wild-type Nox4 enhanced, whereas expression of a dominant negative form of Nox4 suppressed the angiogenic responses in endothelial cells. These effects were mimicked by exogenous H2O2 and the antioxidant compound ebselen, respectively. Overexpression of Nox4 enhanced receptor tyrosine kinase phosphorylation and the activation of extracellular signal-regulated kinase (Erk). Inhibition of the Erk pathway reduced the endothelial angiogenic responses. Nox4 expression also promotes proliferation and migration of endothelial cells, and reduced serum deprivation-induced apoptosis.


CONCLUSIONS
Nox4 type NADPH oxidase promotes endothelial angiogenic responses, at least partly, via enhanced activation of receptor tyrosine kinases and the downstream Erk pathway.
Datla
Srinivasa Raju
SR
Bernard O'Brien Institute of Microsurgery, University of Melbourne, Victoria 3065, Australia.
Peshavariya
Hitesh
H
Dusting
Gregory J
GJ
Mahadev
Kalyankar
K
Goldstein
Barry J
BJ
Jiang
Fan
F
D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology* / Q000378:metabolism; D006801:Humans; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology
D017382:Reactive Oxygen Species; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498910:NOX4 protein, human