Nicotinamide nucleotide transhydrogenase regulates redox balance in atherosclerosis

烟酰胺核苷酸转氢酶调节动脉粥样硬化的氧化还原平衡

• 批准号: 10083960
• 负责人: DAVID M KRZYWANSKI
• 金额: $ 21.8万
• 依托单位: LOUISIANA STATE UNIV HSC SHREVEPORT
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10083960
• 关键词: Animals; Atherosclerosis; Bioenergetics; Biology; Blood Vessels; Cardiovascular Diseases; Cells; Data; Development; Disease; Endothelium; Enzymes; Equilibrium; Excision; High Fat Diet; Human; Lipids; Metabolic Pathway; Mitochondria; Mus; NAD(P)+ transhydrogenase; NADP; Oxidation-Reduction; Phenotype; Plasma; Production; Reactive Oxygen Species; Reduced Glutathione; Regulation; Role; Serum; Superoxide Dismutase; Superoxides; Testing; Vascular Endothelial Cell; chronic inflammatory disease; endothelial dysfunction; glutathione peroxidase; mimetics; oxidant stress; preservation; vascular inflammation

Atherosclerosis, a progressive chronic inflammatory disease of the vessel wall, is regulated by oxidant stress throughout the course of disease development. Endothelial dysfunction is a critical, initiating step in the development of atherosclerosis and increasing evidence implicates mitochondrial reactive oxygen species (ROS) as an important contributor to endothelial dysfunction and vascular inflammation. Nicotinamide nucleotide transhydrogenase (NNT) is emerging as an important enzyme in the regulation of mitochondrial NADPH levels which can have a significant impact on a number of metabolic pathways through the regulation of mitochondrial redox tone (balance of ROS production and removal). Our preliminary data supports this concept and indicates that that the absence of NNT in C57Bl/6J (6J) cells led to distinct mitochondrial bioenergetic profiles and a pro-oxidative mitochondrial phenotype characterized by increased superoxide production and reduced glutathione peroxidase activity. Interestingly, we found that 6J animals are more susceptible to high fat diet induced plaque formation compared to C57Bl/6N (6N). Plaque formation was driven by increased plasma lipids in both animals. However, treatment with the mitochondria targeted superoxide dismutase mimetic MitoTEMPO had distinct effects on serum lipids and plaque formation in the 6N and 6J animals. MitoTEMPO treatment reduced plasma lipids in the 6N animals but not the 6J, and surprisingly, exacerbated plaque formation in the 6J animals, demonstrating a critical role for the production of mitochondrial reactive oxygen species in the development of atherosclerosis in these animals. Building upon these findings, we propose that the loss of NNT activity contributes to a pro-oxidative mitochondrial phenotype that exacerbates the progression of atheroscelrosis by enhancing mitochondrial ROS production, endothelial dysfunction, and vascular inflammation. To test this hypothesis, studies are proposed that will determine i) if NNT inhibits mitochondrial ROS production and preserves normal endothelial •NO function in human vascular endothelial cells; ii) if reduced NNT expression will increase mitochondrial ROS production and stimulate Nox activity that contributes to endothelial dysfunction; and iii) if endothelial NNT critically regulates mitochondrial redox tone and vascular function in mice treated with high fat diet. Data from the proposed studies will identify NNT as a master regulator of mitochondrial function and ROS production whose absence exacerbates the development of atherosclerosis by promoting endothelial dysfunction and vascular inflammation, leading to increased plaque development.

动脉粥样硬化是一种进行性慢性血管壁炎性疾病，在整个疾病发展过程中受到氧化应激的调节。内皮功能障碍是动脉粥样硬化发展的关键起始步骤，越来越多的证据表明线粒体活性氧（ROS）是内皮功能障碍和血管炎症的重要贡献者。烟酰胺核苷酸转氢酶（NNT）是一种重要的线粒体NADPH水平调节酶，通过调节线粒体氧化还原张力（ROS产生和清除的平衡）对许多代谢途径产生重大影响。我们的初步数据支持这一概念，并表明在C57 Bl/6 J（6 J）细胞中NNT的缺乏导致不同的线粒体生物能量谱和促氧化线粒体表型，其特征在于超氧化物产生增加和谷胱甘肽过氧化物酶活性降低。有趣的是，我们发现与C57 B1/6 N（6 N）相比，6 J动物对高脂肪饮食诱导的斑块形成更敏感。在两只动物中，斑块形成由血浆脂质增加驱动。然而，用线粒体靶向超氧化物歧化酶模拟物MitoTEMPO治疗对6 N和6 J动物的血脂和斑块形成具有明显的影响。MitoTEMPO处理降低了6 N动物的血浆脂质，但没有降低6 J动物的血浆脂质，并且令人惊讶地，加剧了6 J动物中的斑块形成，证明了线粒体活性氧物质的产生在这些动物中动脉粥样硬化的发展中的关键作用。基于这些发现，我们提出NNT活性的丧失有助于促氧化线粒体表型，其通过增强线粒体ROS产生、内皮功能障碍和血管炎症而加剧动脉粥样硬化的进展。为了检验这一假设，提出了研究，其将确定i）NNT是否抑制线粒体ROS产生并保留人血管内皮细胞中的正常内皮·NO功能; ii）NNT表达降低是否会增加线粒体ROS产生并刺激Nox活性，从而导致内皮功能障碍;和iii）在用高脂肪饮食处理的小鼠中，内皮NNT是否关键地调节线粒体氧化还原张力和血管功能。来自拟议研究的数据将确定NNT作为线粒体功能和ROS产生的主要调节剂，其缺乏通过促进内皮功能障碍和血管炎症加剧动脉粥样硬化的发展，导致斑块发展增加。