Role of mTORC1 in Retinal Ganglion Cell Physiology and Disease

mTORC1 在视网膜神经节细胞生理和疾病中的作用

• 批准号: 10673155
• 负责人: Steven F Abcouwer
• 金额: $ 52.21万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10673155
• 关键词: Address; Affect; Binding Proteins; Biological Assay; Brain; Cause of Death; Cell Size; Cell Survival; Cell physiology; Cells; Cellular Metabolic Process; Cellular Stress; Characteristics; Clinical; Complex; DNA Damage; Data; Dendrites; Development; Diabetes Mellitus; Diabetic Retinopathy; Disease; Enterobacteria phage P1 Cre recombinase; Exhibits; FRAP1 gene; Functional disorder; Ganglion Cell Layer; Genes; Glaucoma; Goals; Growth; Growth Factor; In Situ; Knowledge; Label; Maintenance; Mediating; Messenger RNA; Metabolic; Metabolism; Multiprotein Complexes; Mus; Nerve Degeneration; Nerve Fibers; Neural Retina; Neurons; Neuropathy; Nutrient availability; Pathway interactions; Peptide Initiation Factors; Phosphotransferases; Physiology; Play; Predisposition; Protein Biosynthesis; Proteins; Retina; Retinal Diseases; Retinal Ganglion Cells; RiboTag; Role; Signal Pathway; Signal Transduction; Stress; Synaptic plasticity; Testing; Thinness; Time; Tissues; Translating; Translational Repression; Translations; Tuberous Sclerosis; Up-Regulation; Vision; Work; adeno-associated viral vector; axon guidance; cell growth; cell motility; cell regeneration; conditional knockout; diabetic; diabetic patient; experimental study; ganglion cell; in vivo; inhibitor; innovation; mRNA Translation; method development; negative affect; nervous system disorder; novel; prevent; protein expression; response; retinal neuron; translatome

PROJECT SUMMARY This work addresses a fundamental knowledge gap in our understanding of retinal physiology and function that has significant bearing on the early effects of diabetes on the neural retina. Mechanistic target of rapamycin (mTOR) kinase forms the core of two multi-protein complexes: mTOR complex 1 (mTORC1) containing the protein Raptor, and mTORC2 complex containing the protein Rictor. The mTOR signaling network is essential for cellular responses to trophic signals, control of cell metabolism, protein synthesis, cell growth and cell motility. Numerous studies show a key role for mTOR complexes in neuronal function, including axon guidance, dendrite arborization and synaptic plasticity; and numerous neurological disorders are associated with dysfunctions of the mTOR signaling pathway. In contrast, knowledge of the roles of mTOR complexes in retinal physiology and disease is very limited. We propose to test a distinct cell-specific role for mTORC1 in normal retinal ganglion cell (RGC) physiology and to determine if loss of mTORC1 activity is a key contributor to loss of RGC function and viability in diabetes. The proposed study is based on our prior findings that diabetes causes progressive loss of total retinal protein synthesis (Fort, P.E. et al. 2014, Diabetes 63(9):3077-90) and preliminary data showing that: 1) mouse RGC exhibit a high rate of protein synthesis that is dependent upon mTORC1 function, and 2) negating mTORC1 function in the inner retina caused eventual loss of RGC, similar to the neurodegeneration causes by diabetes. mTORC1 activity is required for 5' cap- dependent translation of mRNAs encoding the protein-synthetic machinery. Thus, in Specific Aim 1 we plan to examine the role of mTORC1 activity in RGC protein synthesis and maintenance of RGC function and viability. We will test the hypothesis that loss of mTORC1 function in RGC inhibits translation of a discrete set of mRNAs, eventually leading to a decrease in the general protein synthetic capacity, visual function and viability of RGC. The proposal is also based upon the premise that diabetes causes stress and damage to the neural retina, and RGC in particular. Deactivation of mTORC1 decreases 5' cap-dependent protein translation in response to a number of cellular stresses. Preliminary data also show that diabetes diminishes RGC protein synthesis coinciding with increased expression of the stress-responsive inhibitor of mTORC1 called regulated in development and DNA damage (REDD1). Thus, in Specific Aim 2 we plan to determine if the effects of diabetes on RGC mRNA translation, function and viability are due to lack of mTORC1 activity leading to a reduction in protein synthesis capacity. We will test the hypothesis that maintaining mTORC1 activity and RGC protein translation during diabetes prevents RGC loss and dysfunction. Defining the role of mTORC1 in RGC will greatly increase our knowledge of RGC physiology and of the ways in which diabetes affects the neural retina.

项目总结 这项工作解决了我们在理解视网膜生理学和视网膜生理学方面的一个基本知识差距 对糖尿病对神经视网膜的早期影响有重大影响的功能。的机械性目标 雷帕霉素(MTOR)激酶形成两个多蛋白复合体的核心：mTOR复合体1(MTORC1) 含有蛋白质Raptor的mTORC2复合体，以及含有蛋白质Rictor的mTORC2复合体。MTOR信令 网络对于细胞对营养信号的反应、控制细胞新陈代谢、蛋白质合成、细胞 生长和细胞运动。大量研究表明，mTOR复合体在神经元功能中起着关键作用， 包括轴突引导、树突树枝形成和突触可塑性；以及许多神经疾病 与mTOR信号通路功能障碍有关。相比之下，对mTOR作用的了解 复合体在视网膜生理学和疾病方面的研究非常有限。我们建议测试一种不同的细胞特异性作用 MTORC1在正常视网膜神经节细胞(RGC)生理中的作用，并确定mTORC1活性的丧失是否是关键 是糖尿病患者RGC功能和生存能力丧失的原因之一。建议的研究是基于我们先前的发现。 糖尿病导致视网膜总蛋白合成的进行性丧失(Fort，P.E.等人)。2014，糖尿病 63(9)：3077-90)和初步数据显示：1)小鼠RGC表现出较高的蛋白质合成率，即 依赖于mTORC1功能，以及2)否定视网膜内部的mTORC1功能导致最终丧失 与糖尿病引起的神经退行性变相似。5‘CAP-需要mTORC1活动 编码蛋白质合成机制的mRNAs的依赖翻译。因此，在具体目标1中，我们计划 检测mTORC1活性在RGC蛋白合成和RGC功能维持中的作用 和生存能力。我们将检验这样一种假设，即RGC中mTORC1功能的丧失抑制了a 一组离散的mRNA，最终导致一般蛋白质合成能力的下降，视觉 研资局的功能和生存能力。该提案还基于这样一个前提，即糖尿病会导致压力和 对神经视网膜的损害，特别是对RGC的损害。MTORC1失活降低5‘端帽子依赖性 蛋白质翻译对一系列细胞压力的反应。初步数据还显示，糖尿病 抑制RGC蛋白质合成，与应激反应抑制因子的表达增加一致 MTORC1在发育和DNA损伤中被称为调控基因(Redd1)。因此，在具体目标2中，我们计划 确定糖尿病对RGC mRNA翻译、功能和活性的影响是否是由于缺乏 MTORC1活性导致蛋白质合成能力下降。我们将检验这一假设 糖尿病期间维持mTORC1活性和RGC蛋白翻译可防止RGC丢失和功能障碍。 明确mTORC1在RGC中的作用将极大地增加我们对RGC生理和途径的了解 糖尿病会影响神经视网膜。