Role of gp91phox (Nox2)-containing NAD(P)H oxidase in angiogenesis in response to hindlimb ischemia.
BACKGROUND
Neovascularization is potentially important for the treatment of ischemic heart and limb disease. We reported that reactive oxygen species (ROS) derived from gp91phox (Nox2)-containing NAD(P)H oxidase are involved in angiogenesis in mouse sponge models as well as in vascular endothelial growth factor (VEGF) signaling in cultured endothelial cells. The role of gp91phox-derived ROS in neovascularization in response to tissue ischemia is unknown, however.


RESULTS
Here, we show that neovascularization in the ischemic hindlimb is significantly impaired in gp91phox-/- mice as compared with wild-type (WT) mice as evaluated by laser Doppler flow, capillary density, and microsphere measurements. In WT mice, inflammatory cell infiltration in the ischemic hindlimb was maximal at 3 days, whereas capillary formation was prominent at 7 days when inflammatory cells were no longer detectable. Increased O2*- production and gp91phox expression were present at both time points. The dihydroethidium staining of ischemic tissues indicates that O2*- is mainly produced from inflammatory cells at 3 days and from neovasculature at 7 days after operation. Relative to WT mice, ischemia-induced ROS production in gp91phox-/- mice at both 3 and 7 days was diminished, whereas VEGF expression was enhanced and the inflammatory response was unchanged. Infusion of the antioxidant ebselen into WT mice also significantly blocked the increase in blood flow recovery and capillary density after ischemia.


CONCLUSIONS
gp91phox-derived ROS play an important role in mediating neovascularization in response to tissue ischemia. NAD(P)H oxidases and their products are potential therapeutic targets for regulating angiogenesis in vivo.
Tojo
Taiki
T
Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Ga 30322, USA.
Ushio-Fukai
Masuko
M
Yamaoka-Tojo
Minako
M
Ikeda
Satoshi
S
Patrushev
Nikolay
N
Alexander
R Wayne
RW
D000818:Animals; D002196:Capillaries / Q000254:growth & development; D005786:Gene Expression Regulation; D006614:Hindlimb / Q000098:blood supply* / Q000473:pathology; D007249:Inflammation / Q000473:pathology; D007511:Ischemia; D008562:Membrane Glycoproteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D018919:Neovascularization, Physiologic; D017382:Reactive Oxygen Species / Q000378:metabolism; D012039:Regional Blood Flow; D013481:Superoxides / Q000378:metabolism; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics
D008562:Membrane Glycoproteins; D017382:Reactive Oxygen Species; D042461:Vascular Endothelial Growth Factor A; D013481:Superoxides; C488842:Cybb protein, mouse; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases