Inhibition of NAD(P)H oxidase activity blocks vascular endothelial growth factor overexpression and neovascularization during ischemic retinopathy
Inhibition of NAD(P)H oxidase activity blocks vascular endothelial growth factor overexpression and neovascularization during ischemic retinopathy
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DOI：
10.1016/s0002-9440(10)63001-5
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发表时间：
2005-08-01
影响因子：
6
通讯作者：
Caldwall, RB
中科院分区：
文献类型：
--
作者：
Al-Shabrawey, M;Bartoli, M;Caldwall, RB
由于氧化应激与缺血性视网膜病变中血管内皮生长因子（VEGF）表达的上调密切相关，我们评估了NAD(P)H氧化酶在引起VEGF过表达和视网膜新生血管中的作用。在氧诱导视网膜病变的小鼠模型中，双氢乙酯成像分析显示视网膜新生血管区与相对视网膜缺氧相关的超氧化物形成增加。体外化学发光实验证实了缺氧刺激视网膜血管内皮细胞形成超氧化物的作用。NAD(P)H氧化酶活性的特异性抑制剂（apocynin, gp91ds-tat）阻断了超氧化物的形成，表明NAD(P)H氧化酶是超氧化物形成的主要来源。Western blot和免疫定位分析显示，视网膜缺血增加了NAD(P)H氧化酶催化亚基gp91phox的表达，该亚基主要定位于血管内皮细胞。用罗布麻素治疗小鼠可阻断缺血诱导的氧化应激增加，使VEGF表达正常化，并阻止视网膜新生血管形成。Apocynin和gp91ds在体外也阻断了缺氧导致VEGF表达升高的作用，证实了NAD(P)H氧化酶在缺氧诱导的VEGF表达升高中的特殊作用。总之，NAD(P)H氧化酶活性是缺氧刺激下VEGF表达增加和视网膜新生血管形成所必需的。抑制NAD(P)H氧化酶为视网膜病变的治疗提供了新的靶点。
Because oxidative stress has been strongly implicated in up-regulation of vascular endothelial growth factor (VEGF) expression in ischemic retinopathy, we evaluated the role of NAD(P)H oxidase in causing VEGF overexpression and retinal neovascularization. Dihydroethidium imaging analyses showed increased superoxide formation in areas of retinal neovascularization associated with relative retinal hypoxia in a mouse model for oxygen-induced retinopathy. The effect of hypoxia in stimulating superoxide formation in retinal vascular endothelial cells was confirmed by in vitro chemiluminescence assays. The superoxide formation was blocked by specific inhibitors of NAD(P)H oxidase activity (apocynin, gp91ds-tat) indicating that NAD(P)H oxidase is a major source of superoxide formation. Western blot and immunolocalization analyses showed that retinal ischemia increased expression of the NAD(P)H oxidase catalytic subunit gp91phox, which localized primarily within vascular endothelial cells. Treatment of mice with apocynin blocked ischemia-induced increases in oxidative stress, normalized VEGF expression, and prevented retinal neovascularization. Apocynin and gp91ds-tat also blocked the action of hypoxia in causing increased VEGF expression in vitro, confirming the specific role of NAD(P)H oxidase in hypoxia-induced increases in VEGF expression. in conclusion, NAD(P)H oxidase activity is required for hypoxia-stimulated increases in VEGF expression and retinal neovascularization. Inhibition of NAD(P)H oxidase offers a new therapeutic target for the treatment of retinopathy.