Role of H-Ras in retinal cell death in diabetes

H-Ras 在糖尿病视网膜细胞死亡中的作用

• 批准号: 9902447
• 负责人: RENU A. KOWLURU
• 金额: $ 37.72万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9902447
• 关键词: Affect; Amino Acids; Apoptosis; Apoptotic; Binding; Biological; Blindness; Blood Vessels; Blood capillaries; Cell Death; Cells; Complications of Diabetes Mellitus; Cystathionine beta-Synthase; Cysteine; DNA; DNA Methylation; DNA Modification Methylases; DNA Modification Process; Data; Deacetylase; Development; Diabetes Mellitus; Diabetic Retinopathy; Diabetic mouse; Disease; Electron Transport; Endothelial Cells; Environment; Enzyme Activation; Enzymes; Epigenetic Process; Equilibrium; Event; Free Radicals; Functional disorder; Funding; Gelatinase B; Gene Expression; Gene Expression Regulation; Genetic Transcription; Glucose; Goals; Homeostasis; Homocysteine; Human; Hydrogen Sulfide; Hyperglycemia; Impairment; In Vitro; Maintenance; Matrix Metalloproteinases; Mediating; Mediator of activation protein; Metabolic; Metabolism; Methylation; Mitochondria; Mitochondrial DNA; Modification; Molecular; Molecular Genetics; NF-kappa B; Neurons; Oxidative Stress; Pathogenesis; Patients; Pharmacology; Physical condensation; Physiological; Plasma; Play; Process; Proteins; Publishing; RAS genes; Regulation; Research; Respiration; Retina; Retinal Diseases; Rodent; Rodent Model; Role; SIRT1 gene; Sodium; Sulfhydryl Compounds; Testing; Therapeutic; Tissues; Transcription Factor AP-1; Transferase; Translating; Vision; Work; base; diabetic; diabetic patient; histone methylation; histone modification; in vivo; inhibitor/antagonist; innovation; mitochondrial dysfunction; mouse model; new therapeutic target; novel; overexpression; p65; predictive modeling; prevent; promoter; recruit; translational impact; young adult

ABSTRACT Diabetic retinopathy remains a major cause of blindness, and despite cutting edge research in the field, the molecular mechanism of its pathogenesis remains unclear. Our studies have documented a critical role of matrix metalloproteinase 9 (MMP-9) in diabetic retinopathy, and have demonstrated that cytosolic MMP-9 activation is an early event, that is followed by its mitochondrial accumulation, mitochondrial dysfunction and mtDNA damage, initiating a vicious cycle of free radicals. Epigenetic modifications play a critical role in MMP-9 transcription, and in diabetes, MMP-9 promoter DNA undergoes dynamic methylation-hydroxymenthlation and histone modifications. MMP-9 is also regulated by homocysteine, a thiol-containing non-protein amino acid, and diabetic patients have elevated plasma homocysteine levels. Increased homocysteine is implicated in cellular and metabolic abnormalities including mitochondrial damage and epigenetic modifications. Homocysteine is also a precursor of hydrogen sulfide (H2S), and due to impaired homocysteine metabolism, plasma levels of H2S are decreased in diabetic patients. Based on these, our central hypothesis is that in diabetes, high homocysteine activates MMP-9 and disturbs mitochondrial dynamics, and the damaged mitochondria accelerates apoptosis resulting in the development of diabetic retinopathy. Aim 1 will investigate the mechanism(s) by which homocysteine activates MMP-9 in diabetes, and the model predicts that high homocysteine activates MMP-9 by (i) damaging interactions between MMP-9 and its tissue inhibitor, Timp1, and (ii) inducing epigenetic modifications and increasing the ratio of MMP-9-Timp1. Aim 2 will determine the mechanism(s) by which homocysteine impairs mitochondrial dynamics, and will test the hypothesis that homocysteine increases mitochondrial fragmentation, and dysfunctional mitophagy in diabetes fails to properly remove the fragmented mitochondria. Aim 3 will examine the therapeutic potential of regulating homocysteine-H2S metabolic balance on inhibition of diabetic retinopathy. The plan will employ in vitro (retinal endothelial cells) and in vivo (retinal microvessels from rodents) models of diabetic retinopathy, and will utilize fully optimized molecular biological and pharmacological approaches. Our overall goal is to identify novel regulatory mechanisms involved in the pathogenesis of diabetic retinopathy, specifically at the level of regulation of homocysteine-H2S. The proposal is based on a testable central hypothesis, and our proposed studies are innovative and carry a significant translational impact as they are expected to identify novel therapeutic targets to prevent the development and progression of diabetic retinopathy. This will offer patients additional therapeutic means to prevent/halt this sight-threatening complication of diabetes.

抽象的 糖尿病性视网膜病仍然是失明的主要原因，尽管该领域的尖端研究，但 其发病机理的分子机制尚不清楚。我们的研究记录了 糖尿病性视网膜病中基质金属蛋白酶9（MMP-9），并证明了胞质MMP-9 激活是一个早期事件，随后是其线粒体积累，线粒体功能障碍和 mtDNA损坏，引发了自由基的恶性循环。表观遗传修饰在MMP-9中起关键作用 转录，在糖尿病中，MMP-9启动子DNA经历动态甲基化 - 羟基化和 组蛋白修饰。 MMP-9也受同型半胱氨酸的调节，含硫醇的非蛋白氨基酸， 糖尿病患者的血浆同型半胱氨酸水平升高。同型半胱氨酸的增加与 细胞和代谢异常，包括线粒体损伤和表观遗传修饰。 同型半胱氨酸也是硫化氢（H2S）的前体，并且由于同型半胱氨酸代谢受损而导致 糖尿病患者的血浆水平降低。基于这些，我们的中心假设是 糖尿病，高同型半胱氨酸激活MMP-9和干扰线粒体动力学，并受损 线粒体加速凋亡，导致糖尿病性视网膜病的发展。 AIM 1将研究同型半胱氨酸在糖尿病中激活MMP-9的机制，模型 预测高同型半胱氨酸会通过（i）MMP-9及其组织之间的损害相互作用激活MMP-9 抑制剂，TIMP1和（ii）诱导表观遗传修饰并增加MMP-9-TIMP1的比率。 AIM 2意志 确定同型半胱氨酸会损害线粒体动力学的机制，并将测试 假设同型半胱氨酸会增加线粒体碎裂，并且糖尿病功能失调的线粒体 无法正确去除碎片的线粒体。 AIM 3将检查调节的治疗潜力 同型半胱氨酸-H2S代谢平衡抑制糖尿病性视网膜病。该计划将在体外使用（视网膜 内皮细胞）和体内（来自啮齿动物的视网膜微血管）的糖尿病性视网膜病模型，并将利用 完全优化的分子生物学和药理方法。我们的总体目标是确定小说 与糖尿病性视网膜病的发病机理有关的调节机制，特别是在 同型半胱氨酸-H2S的调节。该提案基于可检验的中心假设，我们的提议 研究具有创新性，并具有重大的翻译影响，因为他们预计将确定新颖 预防糖尿病性视网膜病的发展和进展的治疗靶标。这将为病人提供 防止/停止这种威胁糖尿病并发症的其他治疗方法。