Endothelium-dependent coronary vasodilatation requires NADPH oxidase-derived reactive oxygen species.
OBJECTIVE
To determine the functional significance of physiological reactive oxygen species (ROS) levels in endothelium-dependent nitric oxide (NO)-mediated coronary vasodilatation.


RESULTS
Endothelium-derived NO is important in regulating coronary vascular tone. Excess ROS have been shown to reduce NO bioavailability, resulting in endothelial dysfunction and coronary diseases. NADPH oxidase is a major source of ROS in endothelial cells (ECs). By using lucigenin-based superoxide production and dichlorfluorescein diacetate (DCFH-DA) fluorescence-activated cell sorter assays, we found that mouse heart ECs from NADPH oxidase-knockdown (p47(phox-/-)) animals have reduced NADPH oxidase activity (>40%) and ROS levels (>30%) compared with wild-type mouse heart ECs. Surprisingly, a reduction in ROS did not improve coronary vasomotion; rather, endothelium-dependent vascular endothelial growth factor-mediated coronary vasodilatation was reduced by greater than 50% in p47(phox-/-) animals. Western blots and L-citrulline assays showed a significant reduction in Akt/protein kinase B (PKB) and endothelial NO synthase phosphorylation and NO synthesis, respectively, in p47(phox-/-) coronary vessels and mouse heart ECs. Adenoviral expression of constitutively active endothelial NO synthase restored vascular endothelial growth factor-mediated coronary vasodilatation in p47(phox-/-) animals.


CONCLUSIONS
Endothelium-dependent vascular endothelial growth factor regulation of coronary vascular tone may require NADPH oxidase-derived ROS to activate phosphatidylinositol 3-kinase-Akt-endothelial NO synthase axis.
Feng
Jun
J
Department of Surgery, Beth Israel Deaconess Medical Center, Boston, Mass., USA.
Damrauer
Scott M
SM
Lee
Monica
M
Sellke
Frank W
FW
Ferran
Christiane
C
Abid
Md Ruhul
MR
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects / Q000201:enzymology*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology*; D004789:Enzyme Activation; D016166:Free Radical Scavengers / Q000494:pharmacology; D005822:Genetic Vectors; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019255:NADPH Oxidases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014161:Transduction, Genetic; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D042461:Vascular Endothelial Growth Factor A; D014665:Vasodilator Agents; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt