Mechanisms of endothelial response to oxidative aggression:: Protective role of autologous VEGF and induction of VEGFR2 by H2O2
Mechanisms of endothelial response to oxidative aggression:: Protective role of autologous VEGF and induction of VEGFR2 by H2O2
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DOI：
10.1152/ajpheart.01277.2005
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发表时间：
2006-09-01
影响因子：
4.8
通讯作者：
Caramelo, Carlos
中科院分区：
文献类型：
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作者：
Gonzalez-Pacheco, Francisco R.;Deudero, Juan J. P.;Caramelo, Carlos
血管内皮细胞(EC)对活性氧(ROS)的防御机制还不够清楚。我们提出了一种假设，即血管内皮生长因子(VEGF)及其受体是这一反应的相关元件。在单层内皮细胞瞬时暴露于H_2O_2的条件下，研究细胞存活率、血管内皮生长因子及其受体(VEGFR1和VEGFR2)的表达以及转录因子的激活。用野生型和突变型kappa Bα(I kappa Bα)抑制物进一步研究了核因子-kappa B在诱导VEGFR2表达中的作用。H_2O_2浓度为60 mU/M时，对EC有明显的损伤作用，而较低浓度(2~4 mU/M)则表现为细胞保护作用。通过特异性的血管内皮生长因子阻断，细胞保护作用转变为内皮细胞损伤模式，从而揭示了自体血管内皮生长因子的主要作用。暴露于H_2O_2可增加内皮细胞中血管内皮生长因子及其受体2的mRNA和蛋白表达，但不影响血管内皮细胞生长因子受体1的表达。此外，H_2O_2攻击还伴随着核因子-kappaB、激活蛋白-1和特异性蛋白-1核结合的增加。ROS清除剂吡咯烷二硫代氨基甲酸酯的抑制和I kappa Bα的阻断作用支持了NF-kappa B作为H_2O_2诱导VEGFR2基因表达的中介作用。外源性血管内皮细胞生长因子受体2(VEGFR2)表达增加，并诱导内皮细胞表达核因子-kappaB。综上所述，自体血管内皮细胞生长因子在低浓度ROS诱导的EC保护中具有重要作用。ROS不仅能诱导血管内皮生长因子的表达，还能诱导血管内皮细胞生长因子2的表达。ROS增加VEGFR2的作用主要是通过依赖于NF-kappaB的途径来实现的。
The defense mechanisms of endothelial cells (EC) against reactive oxygen species (ROS) are insufficiently characterized. We have addressed the hypothesis that vascular endothelial growth factor (VEGF) and its receptors are relevant elements in this response. Cell viability, VEGF and VEGF receptor (VEGFR1 and VEGFR2) expression, and transcription factor activation were studied on transient exposure of monolayer EC to H2O2. Wild-type and mutant inhibitors of kappa B alpha (I kappa B alpha) constructions were used to further assess the role of NF-kappa B in the induction of VEGFR2 expression. A concentration of H2O2 >= 60 mu M elicited clear-cut damaging effects on EC, whereas lower concentrations (2-4 mu M) were cytoprotective. The cytoprotective effect was shifted to an EC-damaging pattern by means of specific VEGF blockade, therefore revealing a major role of autologous VEGF. Exposure to H2O2 increased VEGF and VEGFR2 mRNA and protein in EC, without affecting VEGFR1 expression. Also, H2O2 challenge was accompanied by increased NF-kappa B, activator protein-1, and specific protein- 1 nuclear binding. A role of NF-kappa B as the mediator of the H2O2 induction of VEGFR2 mRNA expression was supported by inhibition by the ROS scavenger pyrrolidine dithiocarbamate and by the blocking effect of transfected I kappa B alpha. Exposure to exogenous VEGF also increased VEGFR2 and induced NF-kappa B in EC. In summary, autologous VEGF is instrumental for EC protection induced by low concentrations of ROS. ROS induce expression not only of VEGF but also of VEGFR2. VEGFR2 increase by ROS is mainly driven through a NF-kappa B-dependent pathway.