The role of mitochondrial protein thiol modification in endothelial dysfunction

描述（由申请人提供）：线粒体现在作为血管细胞中的一个位点出现，能够调节细胞质中氧化还原细胞信号事件。发生这种情况的机制尚未得到很好的理解，这是本建议的重点。我们最近的研究表明，通过Keap1/Nrf-2系统诱导内源性细胞内抗氧化剂是通过线粒体蛋白硫醇的翻译后修饰来调节的。这一点很重要，因为已知血管中内源性抗氧化蛋白（如血红素加氧酶-1）的缺乏与动脉粥样硬化病变的增加有关，而过度表达则具有保护作用。有趣的是，我们已经证明线粒体蛋白硫醇的修饰通过抑制内源性抗氧化途径导致内皮细胞功能障碍。此外，线粒体硫醇修饰导致乙酰胆碱对主动脉环内皮依赖性血管松弛的减弱。我们的初步数据还表明，线粒体硫醇修饰导致生物能量途径从线粒体氧化磷酸化转向效率较低的糖酵解途径，这可能导致生物能量缺乏。综上所述，这些发现导致了线粒体蛋白硫醇和氧化还原状态的调节将改变血管内皮细胞功能的假设。这将通过追求以下具体目标进行测试：1：确定线粒体蛋白硫醇和氧化还原状态在内皮细胞（EC）对氧化应激的易感性中的作用；2：确定线粒体硫醇修饰和氧化还原状态改变在血管内皮功能障碍中的作用；3 .在动脉粥样硬化小鼠模型中，确定线粒体蛋白硫醇修饰在线粒体氧化应激增加时内皮细胞功能障碍中的机制作用。从完成这些特定目标中获得的信息将深入了解线粒体，特别是线粒体蛋白硫醇在确定与动脉粥样硬化相关的内皮细胞功能障碍中的作用。

DESCRIPTION (provided by applicant): The mitochondrion is now emerging as a site in vascular cells capable of regulating redox cell signaling events in the cytosol. The mechanisms through which this occurs are not well understood and are the focus of this proposal. Our recent studies suggest that the induction of the endogenous intracellular antioxidants through the Keap1/Nrf-2 system is modulated by post-translational modification of mitochondrial protein thiols. This is important because it is known that deficiencies of endogenous antioxidant proteins, such as heme oxygenase-1, in the vasculature are associated with increased development of atherosclerotic lesions, while over-expression is protective. Interestingly, we have shown that modification of mitochondrial protein thiols leads to endothelial cell dysfunction by inhibition of the endogenous antioxidant pathway. In addition, mitochondrial thiol modification results in the attenuation of the endothelium-dependent vasorelaxation of aortic rings in response to acetylcholine. Our preliminary data also demonstrate that mitochondrial thiol modification causes a switch in bioenergetic pathways away from mitochondrial oxidative phosphorylation and toward the less efficient glycolytic pathway, potentially contributing to a bioenergetic deficiency. Taken together these findings have led to the hypothesis that modulation of mitochondrial protein thiol and redox status will alter vascular endothelial cell function. This will be tested by pursuit of the following specific aims: 1: Determine the role of mitochondrial protein thiols and redox status in the susceptibility of endothelial cells (EC) to oxidative stress; 2: Determine the role of mitochondrial thiol modification and altered redox status in vascular endothelial dysfunction; and 3: Determine the mechanistic role of mitochondrial protein thiol modification in endothelial cell dysfunction during increased mitochondrial oxidative stress in atherosclerotic mouse models. The information gained from the accomplishment of these specific aims will give insight into the role of the mitochondrion, particularly mitochondrial protein thiols, in determining endothelial cell dysfunction associated with atherosclerosis. PUBLIC HEALTH RELEVANCE: Oxidative damage is an early event in the development of diseases associated with inflammation. Mitochondria are in cells are often a target for oxidative damage, and some of the most sensitive sites for this damage are the amino acid residues on proteins that contain reactive protein thiols. This project tests the hypothesis that mitochondrial protein thiols are damaged in atherosclerosis and contribute to vascular dysfunction.