How Do Muller Glia Control Circuit-Specific Retinal Synaptogenesis?

穆勒胶质细胞如何控制特定电路的视网膜突触发生？

基本信息

批准号：
9328930
负责人：
Sehwon Koh
金额：
$ 6.1万
依托单位：
DUKE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-01 至 2019-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9328930
关键词：
Age related macular degeneration Astrocytes Binding Biological Models Blocking Antibodies Brain CARTPT gene Calcium Channel Cell Culture Techniques Cells Development Doctor of Philosophy Electron Microscopy Enterobacteria phage P1 Cre recombinase Excitatory Synapse Eye diseases Functional disorder Glaucoma Goals Impairment In Vitro Inner Plexiform Layer Integrins Knock-out Knockout Mice LoxP-flanked allele Maintenance Methods Molecular Muller&apos s cell Mus Natural regeneration Neuraxis Neurodegenerative Disorders Neuroglia Neurons Outcome Pathway interactions Pharmaceutical Preparations Protein Family Rattus Retina Retinal Retinal Degeneration Retinal Diseases Retinal Ganglion Cells Rodent Role Signal Transduction Specificity Subgroup Sum Synapses Testing Thrombospondin 1 Thrombospondins Time Transgenic Mice Viral Vision Work base brain cell cell type cellular targeting effective therapy experimental study gabapentin gene therapy insight molecular targeted therapies nervous system disorder neural circuit novel novel therapeutics promoter receptor repaired small hairpin RNA synaptogenesis therapeutic target thrombospondin 2

Age related macular degeneration Astrocytes Binding Biological Models Blocking Antibodies Brain CARTPT gene Calcium Channel Cell Culture Techniques Cells Development Doctor of Philosophy Electron Microscopy Enterobacteria phage P1 Cre recombinase Excitatory Synapse Eye diseases Functional disorder Glaucoma Goals Impairment In Vitro Inner Plexiform Layer Integrins Knock-out Knockout Mice LoxP-flanked allele Maintenance Methods Molecular Muller&apos s cell Mus Natural regeneration Neuraxis Neurodegenerative Disorders Neuroglia Neurons Outcome Pathway interactions Pharmaceutical Preparations Protein Family Rattus Retina Retinal Retinal Degeneration Retinal Diseases Retinal Ganglion Cells Rodent Role Signal Transduction Specificity Subgroup Sum Synapses Testing Thrombospondin 1 Thrombospondins Time Transgenic Mice Viral Vision Work base brain cell cell type cellular targeting effective therapy experimental study gabapentin gene therapy insight molecular targeted therapies nervous system disorder neural circuit novel novel therapeutics promoter receptor repaired small hairpin RNA synaptogenesis therapeutic target thrombospondin 2

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项目摘要

Synapses are the basic functional units of the central nervous system (CNS). Synaptic dysfunction and synapse loss are hallmarks of neurological disorders including retinal degeneration. However, there currently are no effective therapies that can repair or regenerate these synaptic impairments. Therefore, my long- term goal is to develop cell- and gene-based therapies to repair and/or regenerate these impaired synaptic circuits. In particular, I aim to identify novel cellular and molecular targets for the treatment of retinal degenerative diseases such as age-related macular degeneration and glaucoma. Recent studies have shown that glial cells are important regulators of synapse formation, maintenance and function in the brain. Particularly, astrocytes, major glia cell type in brain, secrete thrombospondin (TSP) family proteins that induce excitatory synapse formation. Unlike brain, Muller glia (MG) are the major glial cell type of the retina, however, how MG regulate neuronal connectivity in the retina remains unclear. In my preliminary experiments, I found that MG secretes TSP1 and TSP2 during early development of the retinal circuitry. TSP1, TSP2 and their synaptogenic receptor α2δ-1 are enriched in the outer and inner plexiform synaptic layers (OPL and IPL, respectively) of the retina. Transgenic mice lacking α2δ-1 (α2δ-1 KO) have dramatically decreased number of synapses in the IPL further supporting their involvements in retinal circuitry development. Particularly, TSP1 is specifically localized at two synaptic sublaminae within the IPL. In vitro studies using purified Retinal Ganglion Cell (RGC) cultures demonstrated that TSP1 specifically promotes synapse formation of On-Off Direction-Selective RGCs (ooDSGCs). TSP1-induced synaptogenesis is inhibited by a function-blocking antibody against Integrin β1, another known receptor of TSP1 that is enriched in ooDSGCs. On the other hand, TSP2 induces formation of synapses onto all RGCs. Based on these findings, I hypothesize that, in the retina, MG-secreted TSPs control different aspects of retinal excitatory synapse development through their common receptor α2δ-1. I further postulate that TSP1 regulates formation of ooDSGCs connectivity through an interaction with Integrin β1 which confers circuit specificity. To test these hypotheses, here I propose two specific aims; 1) To determine the requirement of MG-secreted TSP1 and 2 and their common synaptogenic receptor α2δ-1 for retinal synapse development and function. 2) To determine the role of TSP1/Integrin β1 interaction for the formation of On-Off DSGC specific circuitry. The proposed studies would provide a significant step forward in our understanding of how MG control retinal synaptic development in a circuit specific manner and also would facilitate development of novel therapeutic strategy to repair impaired synaptic circuits. !

突触是中枢神经系统（CNS）的基本功能单位。突触功能障碍和突触丧失是神经系统疾病的标志，包括残留变性。但是，目前没有可以修复或再生这些合成障碍的有效疗法。因此，我的长期术语目标是开发基于细胞和基因的疗法来修复和/或再生这些受损的突触电路。特别是，我旨在确定新型的细胞和分子靶标，以治疗残留退化性疾病，例如与年龄相关的黄斑变性和青光眼。最近的研究表明，神经胶质细胞是突触形成，维持和在大脑中的功能。特别是，星形胶质细胞，大脑中的主要神经胶质细胞类型，秘密血小板传播（TSP）家族诱导兴奋性突触形成的蛋白质。与大脑不同，Muller Glia（mg）是主要的神经胶质细胞类型但是，视网膜MG如何调节视网膜中的神经元连通性尚不清楚。在我的初步实验，我发现MG在其余的早期开发过程中分泌TSP1和TSP2 电路。 TSP1，TSP2及其突触受体α2δ-1富含外部和内丛状视网膜的突触层（OPL和IPL）。缺乏α2δ-1（α2δ-1 KO）的转基因小鼠具有 IPL中突触的数量急剧减少，进一步支持其参与视网膜电路发展。特别是，TSP1在IPL内的两个突触sublaminae中特异性定位。体外使用纯化的视网膜神经节细胞（RGC）培养的研究表明，TSP1专门促进启用方向选择性RGC（OODSGC）的突触形成。 TSP1诱导的突触发生被抑制通过针对整合素β1的功能阻断抗体，这是另一个已知的TSP1受体，它富含在 OODSGC。另一方面，TSP2诱导突触形成所有RGC。基于这些发现，我假设在视网膜中，由MG分泌的TSP控制视网膜的不同方面兴奋性突触通过其公共受体α2δ-1的发育。我进一步假设TSP1调节通过与整合素β1的相互作用，形成OODSGCS的连通性，该β1赋予电路特异性。到检验这些假设，在这里我提出了两个具体目标。 1）确定分泌MG的需求 TSP1和2及其常见的突触受体α2δ-1用于视网膜突触发育和功能。 2）确定TSP1/整合蛋白β1相互作用在启用DSGC形成中的作用特定电路。拟议的研究将在我们理解如何 MG以特定方式控制视网膜突触发育，也将促进修复受损的突触电路的新型热策略。呢