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：
8826750
负责人：
RENU A. KOWLURU
金额：
$ 37.24万
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 2018-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8826750
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 Targeting 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 targeted treatment young adult

项目摘要

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 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.

视网膜病仍然是糖尿病最令人恐惧的并发症之一。在发病机理糖尿病性视网膜病，超氧化物水平显着升高，线粒体功能失调，其DNA 受损，导致超氧化物积累增加的恶性循环。新兴的证据涉及 NADPH氧化酶（NOX）也作为活性氧（ROS）的潜在来源，对对细胞存活。我们的初步数据表明，高血糖激活Rac1/nox2信号轴及其在线粒体失调之前的毛细血管细胞，表明NOX2激活代表早期糖尿病引起的线粒体功能障碍和细胞凋亡中的事件。因此，我们的总体假设是糖尿病中的NOX2衍生的ROS损害视网膜线粒体导致其功能障碍和凋亡毛细血管细胞的加速导致糖尿病性视网膜病的发展。我们建议通过解决下提出的互补问题来进行有条理地检验这一假设三个具体目标。第一个目的将研究高血糖激活NOX2的机制视网膜，并将检验以下假设：在高血糖中，Rac1介导的NOX2激活和ROS 生成启动线粒体损伤和细胞凋亡。由于视网膜病的严重程度是相关的直接与高脂血症，在第二个目标中，脂肪毒性促进的机制将研究糖尿病性视网膜病的发展。我们的工作模型预测脂毒条件促进Rac1介导的NOX2激活和ROS产生以启动线粒体损伤和细胞凋亡。第三个目标将确定NOX2调节对糖尿病发展的影响视网膜病，并将检验以下假设：NOX2的抑制作用将减轻线粒体损伤和随后发展糖尿病性视网膜病。这些提出的研究基于通过多学科生成的引人入胜的初步数据使用有效的体外和体内模型系统之间的两个PI之间的协作工作。我们建议利用 TIAM1/RAC1/NOX2信号通路的已知选择性抑制剂；这些研究的数据将是通过使用非活性突变体和siRNA来确认该途径中的键信号蛋白。体外在体内模型（STZ诱导的糖尿病大鼠和小鼠以及Zucker糖尿病脂肪的体内）中，发现结果将得到进一步验证。大鼠），以及糖尿病性视网膜病的人类捐助者的视网膜中。我们希望证明 RAC-1介导的NOX2衍生成ROS作为线粒体功能障碍的“引发剂”。视网膜病。这应该揭示疗法的新靶标，以防止视网膜病变在其早期阶段开发，并为患者提供其他治疗手段，以防止/阻碍这种威胁性糖尿病并发症。