mTORC1-TFEB pathway in degeneration of the RPE

RPE 变性中的 mTORC1-TFEB 通路

• 批准号: 9986127
• 负责人: Yan Chen
• 金额: $ 38万
• 依托单位: UNIVERSITY OF OKLAHOMA HLTH SCIENCES CTR
• 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 2021-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9986127
• 关键词: Adenoviruses; Affect; Age; Age related macular degeneration; Aging; Atrophic; Autophagocytosis; Biogenesis; Cell physiology; Cells; Cellular Membrane; Cellular Metabolic Process; Clinical; Complex; Defect; Dependence; Disease; Disease Progression; Endosomes; Enzymes; Etiology; Event; Excision; FRAP1 gene; Functional disorder; Genes; Goals; Health; Homologous Gene; Impairment; Ingestion; Intervention; Knock-out; Knowledge; Link; Location; Lysosomes; Measures; Mediating; Melanosomes; Membrane; Membrane Fusion; Methods; Microtubules; Mitochondria; Modeling; Mus; Neurodegenerative Disorders; Ocular Pathology; Organelles; Oxidative Stress; Pathologic; Pathway interactions; Patients; Phagocytosis; Phenotype; Photoreceptors; Physiological; Pigments; Preventive; Process; Protein Kinase; Proteins; Publishing; Regulation; Retina; Retinal; Retinal Degeneration; Retinal Diseases; Role; Satellite Viruses; Signal Pathway; Signal Transduction; Sirolimus; Sorting - Cell Movement; Structure of retinal pigment epithelium; Testing; Therapeutic; Therapeutic Effect; Time; Tuberous sclerosis protein complex; Vacuolar Protein Sorting; Vesicle; Vision; base; bevacizumab; design; gene therapy; genome wide association study; improved; innovation; knock-down; mouse model; novel; overexpression; photoreceptor degeneration; prevent; protein biomarkers; protein transport; recombinase-mediated cassette exchange; spatiotemporal; subretinal injection; success; trafficking; transcription factor

The long-term goal of this project is to elucidate the mechanisms by which membrane trafficking is regulated in retinal pigment epithelium (RPE) cells, and to understand the role of defects in this regulation in retinal diseases including age-related macular degeneration (AMD). The RPE is responsible for the removal of daily shed photoreceptor outer segments (POS) by phagocytosis, which activates tightly controlled processes of membrane trafficking and organelle transport. In our published and preliminary studies, we found that phagocytosis activated signaling pathway mediated by the mechanistic target of rapamycin (mTOR). Under physiological conditions, mTOR activation was transient. Aging and degeneration, however, rendered mTOR activation to become prolonged after morning burst. In our newly developed murine model of RPE-specific deletion of mTORC1 upstream suppressor TSC1, constitutively high mTOR activity led to RPE and photoreceptor degeneration, likely caused by deregulated membrane trafficking and delayed POS degradation. We further identified VPS11, a key component of the membrane tethering complexes, was downregulated in TSC1-deficient RPE cells possibly due to inhibition on the transcription factor EB (TFEB). Based on those novel findings, we hypothesize that hyperactivation of mTORC1 can cause RPE and photoreceptor degeneration due to defective membrane trafficking. Enhancing TFEB-mediated expression of RPE trafficking proteins can restore the cellular functions and prevent the degenerative phenotype in retina of TSC1RPE mice. The hypothesis will be tested by three specific aims. Aim 1 is to further characterize the retinal phenotype of mice with conditional knockout of TSC1 in the RPE. Aim 2 is to determine whether overactivation of mTOR inhibits RPE intracellular trafficking and membrane fusion by inhibiting TFEB-mediated VPS11 expression. Aim 3 is to determine whether TFEB gene therapy can prevent or rescue RPE degeneration. Results from the proposed studies are expected to further establish the critical roles of mTOR in controlling the RPE and photoreceptor interaction. Although anti-VEGF therapy has achieved unprecedented success, the majority of AMD patients have the atrophic form of the disease whose etiology is still largely unknown and treatment options are very limited. Identifying novel targets downstream of mTOR in degenerating RPE cells can facilitate the design of therapeutic strategies to prevent or at least delay the disease progression at early stage of AMD.

该项目的长期目标是阐明膜运输的机制 视网膜色素上皮（RPE）细胞，并了解缺陷在该调节中的作用 包括与年龄相关的黄斑变性（AMD）在内的疾病。 RPE负责每天删除 通过吞噬作用的脱落光感受器的外部片段（POS），该吞噬作用激活了紧密控制的过程 膜贩运和细胞器运输。在我们发表的初步研究中，我们发现 吞噬作用激活的信号通路是由雷帕霉素（MTOR）的机械靶标介导的。在下面 生理条件，mTOR激活是短暂的。但是，老化和变性使MTOR呈现 早晨爆发后的激活延长。在我们新开发的RPE特异性鼠模型中 MTORC1上游抑制剂TSC1的删除，组成性高的MTOR活性导致RPE和 受感受器的变性可能是由于膜运输和延迟POS降解引起的。 我们进一步确定了VPS11，这是膜束缚复合物的关键组成部分，在 由于对转录因子EB（TFEB）的抑制，可能导致TSC1缺陷型RPE细胞。基于这些 新发现，我们假设MTORC1的过度激活会引起RPE和感光体 由于膜运输有缺陷而导致的变性。增强TFEB介导的RPE表达 运输蛋白可以恢复细胞功能并防止视网膜中的退化表型 TSC1RPE小鼠的。该假设将通过三个特定目的进行检验。目标1是进一步描述 RPE中有条件敲除TSC1的小鼠的视网膜表型。目标2是确定是否 MTOR的过度活化通过抑制TFEB介导的RPE抑制RPE细胞内运输和膜融合 VPS11表达。 AIM 3是确定TFEB基因疗法是否可以预防或挽救RPE 退化。预计拟议研究的结果将进一步确立MTOR的关键作用 控制RPE和感光器相互作用。尽管抗VEGF疗法已经实现了前所未有的 成功，大多数AMD患者具有该疾病的萎缩形式，其病因仍然很大 未知和治疗方案非常有限。识别MTOR下游的新颖目标 退化的RPE细胞可以促进治疗策略的设计，以防止或至少延迟 AMD早期的疾病进展。