Regulation of Retinal Cell Death in Diabetes

糖尿病视网膜细胞死亡的调节

• 批准号: 9124905
• 负责人: Steven F Abcouwer
• 金额: $ 55.76万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9124905
• 关键词: Address; Adult; Affect; Apoptosis; Area; Blindness; Blood Vessels; Brain; Cell Death; Cell Survival; Cell physiology; Cells; Cessation of life; Color Visions; Complex; Contrast Sensitivity; Data; Defect; Diabetes Mellitus; Diabetic Retinopathy; Diabetic mouse; Disease; Enzymes; Equilibrium; Exhibits; Eye; FRAP1 gene; Functional disorder; Genes; Genetic Translation; Glaucoma; Goals; Grant; Health; Human; Hyperglycemia; Insulin; Insulin Receptor; Knock-out; Knowledge; Lead; Left; LoxP-flanked allele; Mediating; Mission; Modification; Molecular; Morphology; Mus; Nerve Degeneration; Neural Retina; Nutrient; Optic Nerve Injuries; Pathology; Pathway interactions; Patients; Persons; Phosphorylation; Phosphotransferases; Polyribosomes; Population; Pre-Clinical Model; Preventive treatment; Protein Biosynthesis; Protein Phosphatase 2A Regulatory Subunit PR53; Protein phosphatase; Proteins; Public Health; Rapamycin-Binding Proteins; Raptors; Rattus; Receptor Signaling; Regulation; Research; Retina; Retinal; Retinal Diseases; Retinal Ganglion Cells; Rodent; Rodent Model; Role; Signal Pathway; Signal Transduction; Specificity; Staging; Synapses; Techniques; Testing; Vision; Visual; Visual impairment; Western Blotting; Work; axonal degeneration; bevacizumab; clinically relevant; diabetic; diabetic rat; disability; improved; in vivo; innovation; knock-down; loss of function; macular edema; member; neuron loss; neurosensory; neurovascular unit; novel; protein degradation; protein expression; receptor; recombinase; research study; retinal neuron; targeted treatment; vector

 DESCRIPTION (provided by applicant): There is a fundamental gap in understanding how diabetes impacts the retinal neurons that provide vision. Because of this, current therapies intervene in latter stages of the disease, when blood vessels are affected. Anti-VEGF therapy limits damage in advanced diabetic retinopathy (DR), but does not address damage to the neurosensory retina. Hence, the long-term goal of this project is to define the mechanisms that cause retinal ganglion cell (RGC) dysfunction in patients with DR. The overall objective is to define the roles of mechanistic target of rapamycin complex 2 (mTORC2) signaling in the interactions between hyperglycemia and protein synthesis that lead to RGC dysfunction and subsequent vision loss in DR. The project will utilize diabetic rats and mice, which are the standard pre-clinical models of DR, and which exhibit the early neurodegenerative changes of human DR. The central hypothesis is that diabetes-induced defects in mTORC2 signaling impair protein synthesis, axonal function and survival of retinal ganglion cells. The rationale for this work is that identifying pathways causing RGC dysfunction and death will ultimately lead to preventive treatments and better vision for persons with diabetes. The hypothesis is supported by strong preliminary data showing: 1) prominent mTOR and Rictor expression in RGCs; 2) reduced mTOR expression in diabetic human donor eyes; and 3) the ability to conditionally knockout of Rictor expression in adult mice. The hypothesis will be tested in two specific aims: 1) to define the mechanisms by which diabetes impairs retinal mTORC2 activity and the cell-specific effects of diabetes on protein synthesis, and 2) to define the consequences of impaired mTORC2 activity on retinal ganglion cell protein synthesis, survival and morphology. The first aim will examine the effect of diabetes on mTORC2 complex member protein expression in human retinas, use diabetic rodent models to determine the molecular mechanisms by which diabetes reduces retinal mTORC2 activity and protein synthesis, and examine the cell-specificity of these effects. The second aim will employ in vivo spatial and cell- specific targete loss-of-function studies to disrupt mTORC complexes by knockout of the mTOR-associated proteins Rictor and Raptor in inner retinal neurons and determine the effects on protein turnover, axonal function and cell survival. The proposal is innovative because it: 1) expands the novel observation of diminished mTORC2 activity in DR and investigates the unexplored area of mTOR function in the neural retina; 2) will be the first to examine the cell-specific alterations i retinal mTORC complexes and protein synthesis leading to loss of neuronal integrity in DR; and 3) will use innovative techniques, including translatomics to define cell-specific changes in retinal mRNA translation, and targeted AAV-cre recombinase vectors to delete Rictor, Raptor and protein phosphatase PP2A genes in RGC. The work is significant because it will elucidate clinically relevant means to restore defective signaling pathways responsible for loss of RGC function in retinal diseases that have universal importance to vision and implications for the NEI Audacious Goals Initiatives.

 描述(申请人提供)：在理解糖尿病如何影响提供视力的视网膜神经元方面有一个根本的空白。正因为如此，目前的治疗方法在疾病的后期阶段进行干预，当血管受到影响时。抗血管内皮生长因子治疗限制了晚期糖尿病视网膜病变(DR)的损害，但不能解决对神经感觉性视网膜的损害。因此，该项目的长期目标是确定导致DR患者视网膜神经节细胞(RGC)功能障碍的机制。总体目标是确定雷帕霉素复合体2的机械性靶点(MTORC2)信号在高血糖和蛋白质合成之间的相互作用中的作用，这些相互作用导致DR的RGC功能障碍和随后的视力丧失。该项目将利用糖尿病大鼠和小鼠，它们是DR的标准临床前模型，并展示人类DR的早期神经退行性变化。中心假说是糖尿病导致的mTORC2信号缺陷影响蛋白合成、轴突功能和视网膜神经节细胞的存活。这项工作的基本原理是，确定导致RGC功能障碍和死亡的途径最终将为糖尿病患者带来预防性治疗和更好的视力。这一假说得到了强有力的初步数据的支持，这些数据表明：1)视网膜神经节细胞中mTOR和Rictor的显著表达；2)糖尿病人供体眼中mTOR表达的减少；以及3)成年小鼠有条件地敲除Rictor表达的能力。这一假设将在两个特定目标下进行检验：1)确定糖尿病损害视网膜mTORC2活性的机制以及糖尿病对蛋白质合成的细胞特异性影响；2)确定mTORC2活性受损对视网膜神经节细胞蛋白质合成、存活率和形态的影响。第一个目标是研究糖尿病对人视网膜mTORC2复合体成员蛋白表达的影响，使用糖尿病啮齿动物模型来确定糖尿病降低视网膜mTORC2活性和蛋白质合成的分子机制，并检查这些影响的细胞特异性。第二个目标将利用体内空间和细胞特异性靶向功能丧失研究，通过敲除视网膜内神经元中mTOR相关蛋白Rictor和Raptor来破坏mTORC复合体，并确定对蛋白质周转、轴突功能和细胞存活的影响。该建议具有创新性，因为它：1)扩大了对DR中mTORC2活性降低的新观察，并调查了神经视网膜中mTOR功能的未知领域；2)将首次检测导致DR中神经元完整性丧失的细胞特异性改变I视网膜mTORC复合体和蛋白质合成；以及3)将使用创新技术，包括转译基因组学来定义视网膜mRNA翻译中细胞特异性的变化，以及靶向AAV-cre重组酶载体，以删除RGC中的Rictor、Raptor和蛋白磷酸酶PP2A基因。这项工作意义重大，因为它将阐明临床上相关的方法，以恢复导致视网膜疾病中RGC功能丧失的有缺陷的信号通路，这些信号通路对视力具有普遍重要性，并对NEI大胆目标倡议产生影响。