The expression of the NADPH oxidase subunit p22phox is regulated by a redox-sensitive pathway in endothelial cells
The expression of the NADPH oxidase subunit p22phox is regulated by a redox-sensitive pathway in endothelial cells
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DOI：
10.1016/j.freeradbiomed.2004.09.036
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发表时间：
2005-03-01
影响因子：
7.4
通讯作者：
Görlach, A
中科院分区：
文献类型：
--
作者：
Djordjevic, T;Pogrebniak, A;Görlach, A
内皮功能障碍的特征在于活性氧（ROS）水平增加和血栓前状态。血栓形成与内皮细胞中ROS产生之间的联系机制尚不清楚。我们研究了凝血酶在调节NADPH氧化酶依赖的ROS产生及其亚基p22 phox在内皮细胞系EaHy 926中的表达中的作用。凝血酶引起活性氧产生的双相增加，在15分钟内达到峰值，但也在3小时。延迟反应伴随着p22 phox mRNA和蛋白表达的增加。双光子共聚焦激光显微镜显示p22 phox和ROS的产生之间的共定位。维生素C或diphenyleneiodonium的抗氧化剂处理废除凝血酶诱导的ROS的产生和p22 phox的表达，而H2 O2升高ROS的产生和p22 phox的水平。这两种反应都依赖于p38 MAP激酶和磷脂酰肌醇-3-激酶（PI 3激酶）/Akt。最后，p22 phox所需的凝血酶或H2 O2刺激的增殖。这些数据表明，凝血酶迅速增加ROS的生产在内皮细胞，导致，通过激活p38 MAP激酶和PI 3激酶/Akt，在上调p22 phox伴随着延迟增加ROS的产生和增强的增殖。这些发现表明一种正反馈机制，其中ROS，可能产生的NADPH氧化酶，导致p22 phox的水平升高，因此，持续的ROS生成中所观察到的内皮功能障碍。(C)2004年爱思唯尔公司All rights reserved.
Endothelial dysfunction is characterized by increased levels of reactive oxygen species (ROS) and a prothrombotic state. The mechanisms linking thrombosis to ROS production in the endothelium are not well understood. We investigated the role of thrombin in regulating NADPH oxidase-dependent ROS production and expression of its subunit p22phox in the endothelial cell line EaHy926. Thrombin elicited a biphasic increase in ROS generation peaking within 15 min, but also at 3 h. The delayed response was accompanied by increased p22phox mRNA and protein expression. Two-photon confocal laser microscopy showed colocalization between p22phox and ROS production. Antioxidant treatment with vitamin C or diphenyleneiodonium abrogated thrombin-induced ROS production and p22phox expression, whereas H2O2 elevated ROS production and p22phox levels. Both responses were dependent on p38 MAP kinase and phosphatidylinositol-3-kinase (PI3 kinase)/Akt. Finally, p22phox was required for thrombin- or H2O2-stimulated proliferation. These data show that thrombin rapidly increases ROS production in endothelial cells, resulting, via activation of p38 MAP kinase and PI3 kinase/Akt, in upregulation of p22phox accompanied by a delayed increase in ROS generation and enhanced proliferation. These findings suggest a positive feedback mechanism whereby ROS, possibly generated by the NADPH oxidase, lead to elevated levels of p22phox and, thus, sustained ROS generation as is observed in endothelial dysfunction. (C) 2004 Elsevier Inc. All rights reserved.