Reactive oxygen species mediate the activation of Akt/protein kinase B by angiotensin II in vascular smooth muscle cells
Reactive oxygen species mediate the activation of Akt/protein kinase B by angiotensin II in vascular smooth muscle cells
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DOI：
10.1074/jbc.274.32.22699
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发表时间：
1999-08-06
影响因子：
4.8
通讯作者：
Griendling, KK
中科院分区：
文献类型：
--
作者：
Ushio-Fukai, M;Alexander, RW;Griendling, KK
血管紧张素II是一种肥大/抗凋亡激素，在血管平滑肌细胞(VSMCs)中利用活性氧(ROS)作为生长相关的信号分子。最近，细胞存活蛋白激酶Akt/蛋白激酶B(PKB)被认为参与蛋白质合成。在这里，我们显示血管紧张素II引起Akt/PKB的快速磷酸化(6+/-0.4倍增加)。外源H_2O_2(50-200 mU M)也能刺激Akt/PKB的磷酸化(最大增加8~+/-0.2倍)，提示Akt/PKB的激活是氧化还原敏感的。血管紧张素II和H_2O_2对血管紧张素II和H_2O_2的激活均被磷脂酰肌醇3-激酶(PI3-K)抑制剂Wortmannin和LY294002(2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one)，所阻断，提示PI3-K是AKT/PKB激活的上游介质，此外，黄素氧化酶的抑制剂二苯碘或过表达过氧化氢酶以阻断血管紧张素II诱导的细胞内H_2O_2的产生显著抑制血管紧张素II诱导的AKT/PKB的磷酸化，表明ROS在激动剂诱导的AKT/PKB激活中起作用。在感染显性阴性Akt/PKB的VSMCs中，血管紧张素II刺激的[H-3]亮氨酸掺入减弱。因此，我们的研究表明Akt/PKB是血管紧张素II信号通路的一部分，并为ROS协调的高度组织化的信号机制提供了洞察力，这些信号机制介导了血管平滑肌细胞对血管紧张素II的肥大反应。
Angiotensin II, a hypertrophic/anti-apoptotic hormone, utilizes reactive oxygen species (ROS) as growth-related signaling molecules in Vascular smooth muscle cells (VSMCs). Recently, the cell survival protein kinase Akt/protein kinase B (PKB) was proposed to be involved in protein synthesis. Here we show that angiotensin II causes rapid phosphorylation of Akt/PKB (6- +/- 0.4-fold increase). Exogenous H2O2 (50-200 mu M) also stimulates Akt/PKB phosphorylation (maximal 8- +/- 0.2-fold increase), suggesting that Akt/PKB activation is redox-sensitive. Both angiotensin II and H2O2 stimulation of Akt/PKB are abrogated by the phosphatidylinositol 3-kinase (PI3-K) inhibitors wortmannin and LY294002 (2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one), suggesting that PI3-K is an upstream mediator of Akt/PKB activation in VSMCs, Furthermore, diphenylene iodonium, an inhibitor of flavin-containing oxidases, or overexpression of catalase to block angiotensin II-induced intracellular H2O2 production significantly inhibits angiotensin II-induced Akt/PKB phosphorylation, indicating a role for ROS in agonist-induced Akt/PKB activation. In VSMCs infected with dominant-negative Akt/PKB, angiotensin II-stimulated [H-3]leucine incorporation is attenuated. Thus, our studies indicate that Akt/PKB is part of the remarkable spectrum of angiotensin II signaling pathways and provide insight into the highly organized signaling mechanisms coordinated by ROS, which mediate the hypertrophic response to angiotensin II in VSMCs.