Mitochondrial Oxidative Stress In Angiotensis II Induced Endothelial Dysfunction

血管紧张素 II 诱导的内皮功能障碍中的线粒体氧化应激

基本信息

批准号：
7987252
负责人：
Sergey Dikalov
金额：
$ 40.17万
依托单位：
EMORY UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-07-15 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7987252
关键词：
Acute Affect Aftercare Angiotensin II Animals Antioxidants Aorta Attenuated Biological Availability Blood Pressure Blood Vessels Cations Cells Charge Cultured Cells Data Development Disease Dose Electrons Endothelial Cells Endothelium Feedback Functional disorder Health Hydrogen Peroxide Hypertension Impairment Individual Lead Mediating Membrane Potentials Mitochondria Mus NADPH Oxidase Nitric Oxide Organelles Oxidation-Reduction Oxidative Stress Pathogenesis Pathway interactions Play Production Protein Isoforms Reactive Oxygen Species Recovery Regulation Relaxation Respiration Role SOD2 gene SRC gene Site Small Interfering RNA Societies Source Supplementation Techniques Therapeutic Agents Time Tissues Transfection United States Vasodilation Work cell growth regulation cellular targeting feeding human CYBA protein human SOD2 protein hypertension treatment improved inhibitor/antagonist mimetics mitochondrial K(ATP) channel mitochondrial dysfunction mutant new therapeutic target overexpression prevent public health relevance tempol

项目摘要

DESCRIPTION (provided by applicant): With more than 50 million individuals affected, the United States is facing a serious challenge in the treatment of hypertension. Oxidative stress is strongly implicated in the pathogenesis of hypertension; however, the role of mitochondrial oxidative stress is not clear. We have found that angiotensin II induces mitochondrial oxidative stress via PKC-dependent activation of NADPH oxidases. This result in activation of mitoKATP channels leading to mitochondrial dysfunction and increase in O27 and H2O2 production by mitochondria. Through a positive feedback loop, the increased mitochondrial H2O2 lead to further activation of cellular NADPH oxidases via c-Scr pathway, resulting in increased cellular O27 production and diminished NO7 bioavailability. This vicious cycle is responsible for overproduction of vascular O27, diminished endothelial NO7 and result in endothelial dysfunction. We suggest that we can interrupt this vicious cycle in endothelial cells by inhibition of mitochondrial oxidative stress using mitochondria-targeted antioxidants. Indeed, treatment of endothelial cells with mitochondria- targeted SOD mimetic mitoTEMPO or inhibition of mitoKATP channels reduced mitochondrial oxidative stress, improved mitochondrial respiration, blocked AngII-induced endothelial oxidative stress and restored NO7. This proposal will investigate the upstream and downstream cellular regulations of mitochondrial ROS. We will examine the role of NOX by depletion or overexpression of specific NOX isoforms using siRNA and transfection techniques. The role of mitochondrial PKC5 in stimulation of mitoKATP dependent production of mitochondrial ROS will be examined. The downstream effect of mitochondrial ROS in redox regulation of c-Src dependent activation of NADPH oxidase will be studied using constitutively active mutant c-Src Y527F. In this proposal we will examine the role of mitochondrial impairment in endothelial dysfunction. Our preliminary data showed that overexpression of mitochondrial superoxide dismutase (SOD2) inhibited AngII-induced endothelial oxidative stress and restored NO7. We suggest that a cross-talk between mitochondrial dysfunction and mitochondrial oxidative stress may constitute a mitochondrial impairment, which drives endothelial dysfunction. In this proposal we will study the effect of mitoTEMPO, SOD2 depletion or overexpression on mitochondrial and endothelial functions. Finally, we will investigate the role of mitochondrial ROS in Ang II - and DOCA-salt induced hypertension using C57Blk/6, tgSOD2 and SOD2() mice. For the first time we have found that treatment of hypertensive animals with mitoTEMPO significantly reduced vascular oxidative stress, increased NO7, improved endothelial dependent relaxation and attenuated hypertension, while the same dose of non-targeted antioxidant TEMPOL did not. The overall objective of this proposal is to gain a clear understanding of the role of mitochondrial oxidative stress in endothelial dysfunction and hypertension, which may provide critical information for the development of new mitochondria-targeted therapeutic agents to treat hypertension. PUBLIC HEALTH RELEVANCE: Oxidative stress is strongly implicated in the pathogenesis of hypertension; however, the role of mitochondrial oxidative stress is not clear. Our preliminary data showed that inhibition of mitochondrial oxidative stress significantly improves endothelial function and attenuates hypertension. This work will study the role of mitochondrial oxidative stress in endothelial dysfunction and provide a novel therapeutic target to treat and prevent hypertension.

描述（由申请人提供）：在受影响的超过5000万个人中，美国在治疗高血压方面面临严重的挑战。氧化应激与高血压的发病机理非常重要。但是，线粒体氧化应激的作用尚不清楚。我们发现，血管紧张素II通过PKC依赖性NADPH氧化酶诱导线粒体氧化应激。这导致线粒体激活线粒体功能障碍并增加了线粒体的O27和H2O2产生。通过正反馈回路，线粒体H2O2的增加导致通过C-SCR途径进一步激活细胞NADPH氧化酶，从而导致细胞O27产生增加并降低NO7生物利用度。这种恶性循环导致血管O27的过量生产，内皮NO7减少，并导致内皮功能障碍。我们建议我们可以使用靶向线粒体靶向的抗氧化剂来抑制线粒体氧化应激，从而在内皮细胞中中断这种恶性循环。实际上，用线粒体靶向的SOD模拟线粒体处理内皮细胞或抑制MitokATP通道可减少线粒体氧化应激，改善线粒体呼吸，阻断ANGII诱导的内皮氧化应激，并恢复NO7。该建议将研究线粒体ROS的上游和下游细胞法规。我们将使用siRNA和转染技术来检查NOX的作用或过表达特定NOX同工型的作用。线粒体PKC5在刺激线粒体ROS产生的刺激中的作用。线粒体ROS对NADPH氧化酶的氧化还原依赖性激活的下游效应将使用组成性活性突变体C-SRC Y527F研究。在此提案中，我们将研究线粒体损伤在内皮功能障碍中的作用。我们的初步数据表明，线粒体超氧化物歧化酶（SOD2）的过表达抑制了Angii诱导的内皮氧化应激，并恢复了NO7。我们建议线粒体功能障碍与线粒体氧化应激之间的串扰可能构成线粒体损伤，可驱动内皮功能障碍。在此提案中，我们将研究mitotempo，SOD2耗竭或过表达对线粒体和内皮功能的影响。最后，我们将使用C57BLK/6，TGSOD2和SOD2（）小鼠研究线粒体ROS在ANG II和DOCA -SALT诱导的高血压中的作用。我们第一次发现，用丝蒂姆波的治疗高血压动物显着降低了血管氧化应激，增加了NO7，改善了内皮依赖性弛豫和减轻高血压，而相同剂量的非靶向抗氧化剂tempol则没有。该提案的总体目的是清楚地了解线粒体氧化应激在内皮功能障碍和高血压中的作用，这可能为开发新的线粒体靶向治疗剂的发展提供关键信息，以治疗高血压。公共卫生相关性：氧化应激与高血压的发病机理非常重要；但是，线粒体氧化应激的作用尚不清楚。我们的初步数据表明，线粒体氧化应激的抑制可显着改善内皮功能并减轻高血压。这项工作将研究线粒体氧化应激在内皮功能障碍中的作用，并为治疗和预防高血压提供新的治疗靶标。