权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

NADPH Oxidase, Mitochondrial Dysfunction and Diabetic Retinopathy

NADPH 氧化酶、线粒体功能障碍和糖尿病视网膜病变

基本信息

批准号：
8534341
负责人：
RENU A. KOWLURU
金额：
$ 5.05万
依托单位：
WAYNE STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-04-01 至 2016-02-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8534341
关键词：
Address Age Anabolism Apoptosis Apoptotic Attenuated Biological Models Blindness Blood Vessels Blood capillaries Cell Survival Cells Ceramides Characteristics Complications of Diabetes Mellitus Cytosol DNA Data Development Diabetes Mellitus Diabetic Retinopathy Diabetic mouse Disease Drug Delivery Systems Effectiveness Endothelial Cells Event Fright Fumonisin B1 Functional disorder G-Protein Signaling Pathway Generations Glucose Holoenzymes Human Hyperglycemia Hyperlipidemia In Vitro Inflammatory Laboratories Lesion Lipids Mediating Membrane Mitochondria Modeling Molecular Mus NADPH Oxidase Obesity Oxidative Stress Palmitates Pathogenesis Pathology Pathway interactions Patients Pericytes Phagocytes Phosphorylation Rattus Reaction Reactive Oxygen Species Regulation Research Retina Retinal Retinal Diseases Retinopathy of Prematurity Rodent Model Role Saturated Fatty Acids Severities Signal Pathway Signal Transduction Signaling Protein Source Specific qualifier value Staging Superoxides Testing Therapeutic Vascular Endothelial Growth Factors Vision Work base capillary cytochrome c diabetic diabetic rat in vivo Model inhibitor/antagonist insight mitochondrial dysfunction mutant novel oxidative damage prenylation prevent retinal apoptosis retinal damage young adult

项目摘要

DESCRIPTION (provided by applicant): Retinopathy remains one of the most feared debilitating complications of diabetes. In the pathogenesis of diabetic retinopathy, superoxide levels are significantly elevated, mitochondria are dysfunctional and their DNA is damaged resulting in a vicious cycle of increased superoxide accumulation. Emerging evidence implicates NADPH oxidase (Nox) also as a potential source of reactive oxygen species (ROS) with detrimental effects on cell survival. Our preliminary data show that hyperglycemia activates Rac1/Nox2 signaling axis in the retina and its capillary cells prior to mitochondrial dysregulation suggesting that Nox2 activation represents an early event in diabetes-induced mitochondrial dysfunction and cell apoptosis. Thus, our overall hypothesis is that Nox2-derived ROS in diabetes damage retinal mitochondria leading to their dysfunction, and apoptosis of capillary cells is accelerated resulting in the development of diabetic retinopathy. We propose to test this hypothesis methodically by addressing complementary questions proposed under three specific aims. The first aim will investigate the mechanism(s) by which hyperglycemia activates Nox2 in the retina, and will test the hypothesis that in hyperglycemia Rac1-mediated Nox2 activation and ROS generation initiate mitochondrial damage and cellular apoptosis. Since the severity of retinopathy is associated directly with hyperlipidemia, in the second aim, the mechanism(s) by which lipotoxic conditions promote the development of diabetic retinopathy will be investigated. Our working model predicts that lipotoxic conditions promote Rac1-mediated Nox2 activation and ROS generation to initiate mitochondrial damage and cellular apoptosis. The third aim will determine the effect of regulation of Nox2 on the development of diabetic retinopathy, and will test the hypothesis that inhibition of Nox2 will attenuate mitochondrial damage and subsequent development of diabetic retinopathy. These proposed studies are based on compelling preliminary data generated via multi-disciplinary collaborative efforts between two PIs using valid in vitro and in vivo model systems. We propose to utilize known selective inhibitors of the Tiam1/Rac1/Nox2 signaling pathways; data from these studies will be confirmed via the use of inactive mutants and siRNAs for key signaling proteins in this pathway. In vitro findings will be further validated in vivo models (stz-induced diabetic rats and mice, and Zucker diabetic fatty rats), and also in the retina from human donors with diabetic retinopathy. We expect to demonstrate the role of Rac-1-mediated Nox2 derived ROS as the 'initiator' of mitochondrial dysfunction in the pathogenesis of retinopathy. This should reveal novel targets for therapies to prevent retinopathy in the early stages of its development, and offer patients additional therapeutic means to prevent/retard this sight-threatening complication of diabetes.

描述（由申请人提供）：视网膜病变仍然是糖尿病最可怕的衰弱性并发症之一。在糖尿病视网膜病变的发病机制中，超氧化物水平显著升高，线粒体功能失调，DNA受损，导致超氧化物积累增加的恶性循环。越来越多的证据表明，NADPH氧化酶（Nox）也是活性氧（ROS）的潜在来源，对细胞存活有不利影响。我们的初步数据显示，在线粒体失调之前，高血糖激活视网膜及其毛细血管细胞中的Rac1/Nox2信号轴，这表明Nox2激活代表了糖尿病诱导的线粒体功能障碍和细胞凋亡的早期事件。因此，我们的总体假设是糖尿病中nox2来源的ROS损伤视网膜线粒体导致其功能障碍，毛细血管细胞凋亡加速导致糖尿病视网膜病变的发生。我们建议通过解决三个具体目标下提出的互补问题来有条不紊地检验这一假设。第一个目的是研究高血糖激活视网膜中Nox2的机制，并验证在高血糖中rac1介导的Nox2激活和ROS生成引发线粒体损伤和细胞凋亡的假设。由于视网膜病变的严重程度与高脂血症直接相关，在第二个目标中，脂毒性疾病促进糖尿病视网膜病变发展的机制将被研究。我们的工作模型预测，脂毒性条件会促进rac1介导的Nox2激活和ROS生成，从而引发线粒体损伤和细胞凋亡。第三个目的是确定Nox2调控对糖尿病视网膜病变发展的影响，并验证抑制Nox2会减轻线粒体损伤和糖尿病视网膜病变后续发展的假设。这些拟议的研究是基于通过两个pi之间使用有效的体外和体内模型系统的多学科合作努力产生的令人信服的初步数据。我们建议利用已知的Tiam1/Rac1/Nox2信号通路的选择性抑制剂；这些研究的数据将通过对该途径中关键信号蛋白的失活突变体和sirna的使用得到证实。体外研究结果将在体内模型（stz诱导的糖尿病大鼠和小鼠，Zucker糖尿病脂肪大鼠）以及患有糖尿病视网膜病变的人类供体视网膜中进一步验证。我们希望证明rac -1介导的Nox2衍生ROS在视网膜病变发病机制中作为线粒体功能障碍的“发起者”的作用。这将揭示新的治疗靶点，在其发展的早期阶段预防视网膜病变，并为患者提供额外的治疗手段，以预防/延缓这种威胁视力的糖尿病并发症。