Pathogenic Role of DNA-Damage Response Pathway in the Diabetic Retina

DNA 损伤反应途径在糖尿病视网膜中的致病作用

• 批准号: 9542820
• 负责人: PARTHA S SARKAR
• 金额: $ 34.88万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9542820
• 关键词: Acetylation; Affect; Animal Model; Animals; Antioxidants; Apoptosis; Apoptotic; Awareness; Biochemical Pathway; Biogenesis; Blood Vessels; Brain; Cell Death; Cells; Chronic; Clinical Trials; Complications of Diabetes Mellitus; Consensus; DNA Damage; Data; Development; Diabetes Mellitus; Diabetic Retinopathy; Disease; Down-Regulation; Energy Metabolism; Exclusion; Exposure to; Genetic Transcription; Goals; Homeostasis; Human; Hyperglycemia; Individual; Inflammation; Inflammatory; Insulin-Dependent Diabetes Mellitus; Investigation; Knowledge; Link; Machado-Joseph Disease; Mediating; Metabolic; Metabolic Pathway; Mitochondria; Modification; Molecular; Nerve Degeneration; Neurons; Nuclear; Oxidation-Reduction; Oxidative Phosphorylation; Oxidative Stress; Pathogenicity; Pathway interactions; Patients; Phosphotransferases; Photoreceptors; Play; Production; Regulation; Research; Retina; Retinal; Retinal Diseases; Role; Signal Pathway; Signal Transduction; Site; Stimulus; Testing; Transcription Coactivator; Virulence Factors; Work; ataxia telangiectasia mutated protein; base; cytokine; diabetic; ds-DNA; experimental study; genome integrity; insight; mitochondrial dysfunction; novel; oxidative DNA damage; repaired; response; sensor; tissue culture; virtual

Diabetic retinopathy has been associated with oxidative stress, mitochondrial dysfunction, and chronic activation of inflammatory and degenerative pathways. Substantial evidence implicates the retinal mitochondrial ‒ oxidative stress axis as a major unifying pathogenic factor for virtually all diabetes-induced cellular changes implicated in the development of retinal complications. Therapies directed against these individual pathways have provided disappointing results in human clinical trials. Likewise, clinical trials utilizing antioxidants have produced equally ambiguous results. Taken together, these trials suggest a significant knowledge gap regarding underlying mechanism(s) linking oxidative stress to activation of pro-inflammatory and pro-degenerative pathways in diabetic retinas. Based on our previous work in Spinocerebellar ataxia type 3 patients, together with new data provided in this revised application using relevant retinal cells, we propose the novel hypothesis that ROS-mediated DNA damage in diabetes chronically activates the DNA damage response (DDR) ATM (ataxia-telangiectasia mutated) pathway. There is a strong link between increased DNA damage accumulation and development of diabetic complications including retinopathy. Also, there is a growing consensus that ATM not only acts as a DNA damage sensor to coordinate repair of damaged sites to maintain genome integrity but also plays a critical role in modulating the activities of cellular metabolic sensors to interfere with mitochondrial function, cellular energy homeostasis, inflammation, and apoptosis. How the DDR-ATM pathway interconnects various signaling components to disrupt cellular energy metabolism and enhance pro-degenerative signaling is the subject of intense investigation but remains unexplored in the retina. Our recent studies have shown that chronic activation of the DDR pathway interferes with mitochondrial function by suppressing PGC-1α activity, a key transcription co-activator that regulates mitochondrial biogenesis, oxidative phosphorylation, and cellular energy homeostasis. Our new preliminary data demonstrating increased DNA damage and ATM activation in diabetic retina supports our hypothesis. The experiments proposed in this application will test the central hypothesis that diabetes-induced oxidative stress causes double stranded DNA damage resulting in ATM activation, leading to downregulation of PGC1α that impacts multiple pathogenic pathways observed in diabetic retinas. We hypothesize that ATM activation induces a significant amplification of diabetes-induced oxidative stress via mitochondrial disruption by multiple mechanisms (aim 1), vascular and neuronal degeneration (aim 2), and chronic inflammation (aim 3). These aims have the potential to establish a unifying molecular mechanism that links enhanced DNA damage to chronic oxidative, degenerative, and inflammatory abnormalities observed in diabetes. The greatest impact of our work is to provide a regulatory mechanism offering a novel explanation for how hyperglycemia impacts mitochondrial dysfunction to amplify oxidative, inflammatory and degenerative changes in the retina. PHS 398/2590 (Rev. 06/09) Page Continuation Format Page

糖尿病视网膜病变与氧化应激、线粒体功能障碍和慢性 炎症和退行性途径的激活。大量证据表明视网膜 线粒体 - 氧化应激轴是几乎所有糖尿病诱发的主要统一致病因素 与视网膜并发症的发展有关的细胞变化。针对这些的治疗 个别途径在人体临床试验中提供了令人失望的结果。同样，临床试验利用 抗氧化剂也产生了同样模糊的结果。总而言之，这些试验表明， 关于氧化应激与促炎症激活之间的潜在机制的知识差距 和糖尿病视网膜的促退行性途径。基于我们之前对脊髓小脑共济失调类型的研究 3 名患者，连同本修订后的申请中使用相关视网膜细胞提供的新数据，我们建议 糖尿病中 ROS 介导的 DNA 损伤会长期激活 DNA 损伤的新假设 反应（DDR）ATM（共济失调毛细血管扩张突变）途径。 DNA 增加之间存在密切联系 糖尿病并发症（包括视网膜病变）的损害累积和发展。另外，还有一个 越来越多的共识认为，ATM 不仅充当 DNA 损伤传感器来协调受损位点的修复， 维持基因组完整性，而且在调节细胞代谢传感器的活动中也发挥着关键作用 干扰线粒体功能、细胞能量稳态、炎症和细胞凋亡。如何 DDR-ATM 通路将各种信号成分互连起来，破坏细胞能量代谢并 增强促退行性信号传导是深入研究的主题，但在视网膜中仍未得到探索。 我们最近的研究表明，DDR 通路的慢性激活会干扰线粒体 通过抑制 PGC-1α 活性发挥功能，PGC-1α 是调节线粒体的关键转录辅激活因子 生物发生、氧化磷酸化和细胞能量稳态。我们的新初步数据 糖尿病视网膜中 DNA 损伤和 ATM 激活增加支持了我们的假设。这 本申请中提出的实验将检验糖尿病诱导的氧化作用的中心假设 压力导致双链 DNA 损伤，导致 ATM 激活，导致 PGC1α 下调 这会影响糖尿病视网膜中观察到的多种致病途径。我们假设 ATM 激活 通过多种途径破坏线粒体，显着放大糖尿病引起的氧化应激 机制（目标 1）、血管和神经元变性（目标 2）和慢性炎症（目标 3）。这些 目标有可能建立一个统一的分子机制，将增强的 DNA 损伤与 糖尿病中观察到的慢性氧化、退行性和炎症异常。最大的影响是 我们的工作是提供一种调节机制，为高血糖如何影响提供新的解释 线粒体功能障碍会加剧视网膜的氧化、炎症和退行性变化。 PHS 398/2590（修订版 06/09） 页面延续 格式页面