Mechanisms underlying CD3ζ guided assembly of retinal circuits

CD3γ 引导视网膜电路组装的机制

• 批准号: 10034400
• 负责人: Ning Tian
• 金额: $ 38.13万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-30 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10034400
• 关键词: Adult; Affect; Axon; Brain; Cell physiology; Cells; Central Nervous System Diseases; Cone; Data; Defect; Development; Disease; Economic Burden; Ensure; Etiology; Eye; Eye diseases; Fostering; Genetic; Glaucoma; Glutamate Receptor; Glutamates; Growth; Impairment; Label; Lead; Light; Major Histocompatibility Complex; Mediating; Methods; Molecular Genetics; Mus; Mutation; Natural regeneration; Nervous system structure; Neurons; Output; Phenotype; Play; Population; Positioning Attribute; Regulation; Retina; Retinal Diseases; Retinal Ganglion Cells; Role; Series; Signal Transduction; Specific qualifier value; Specificity; Structure; Synapses; Techniques; Testing; Vision; Visual; Visual impairment; Visual system structure; Wild Type Mouse; base; cell type; design; effective therapy; in vivo; insight; knock-down; malformation; mutant; nervous system disorder; neural circuit; neuron development; novel; overexpression; postnatal development; prevent; receptor; response; retinal neuron; small hairpin RNA; social; synaptic function; synaptogenesis; tool; visual processing

The mammalian nervous system is composed of billions of neurons, and the precise assembly of these neurons into circuits ensures proper functionality. In the retina, the diverse but precise wiring between bipolar cells (BCs) and retinal ganglion cells (RGCs) serve as the structural basis for circuit processing of visual signals from outer retina to the inner retina. Defects in these wirings lead to severe retinal diseases. The most common example of these diseases is glaucoma, which imputes a significant social and economic burden on the US population. A major obstacle to developing effective therapies to regenerate BC to RGC wirings is our poor understanding of the structure of these circuits and the mechanisms ensuring BCs and RGCs to wire up precisely. In this proposal, we illustrate the cellular strategy of function specific BC to RGC wiring and how CD3ζ selectively instruct RGCs to target various BC types for wiring. To illustrate the assembly of function-specific circuits, we developed a novel transcellular labeling technique to label BCs synaptically wired to function-specific RGCs. Our results on a specific type of DS-RGCs, BD-RGCs, are comparable to those from EM connectomic studies. Our results also show that two different RGC types synapse with distinct BC types, suggesting RGC type-specific wiring with BC types. These studies position us to examine more RGC types and to reveal the underlying mechanisms guiding the assemble of each RGC type with various BC types. Toward this end, we found that mutation of CD3ζ, a receptor for class I major histocompatibility complex (MHCI), eliminates synaptic connections of cone BCs to BD-RGCs but increase synaptic connections of cone BCs to J-RGCs, thus allowing RGC type-specific synaptic regulation. The defects in synaptic wiring of cone BCs to BD-RGCs in CD3ζ mutants significantly impair the light-evoked responses of BD-RGCs, suggesting that precise BC-RGC synaptic wirings are necessary to ensure function specificity of RGCs. To further test this idea, we will identify the BC types wired to additional 4 RGC types and the synaptic function of these RGCs to reveal the cellular strategy responsible for specifying RGC function. We will also examine how CD3ζ instructs synapse formation and function of these RGCs. To uncover the mechanisms underlying CD3ζ-mediated synaptic assembly, we showed that knockdown or overexpress CD3ζ in RGCs of wildtype mice or CD3ζ mutants only induced phenotypes in transduced RGCs, suggesting a cell-autonomous mechanism. To further expand our understanding of the mechanisms, we will perform a series analyses to determine whether CD3ζ is specifically required for the dendritic development of RGCs, whether it is sufficient for the dendritic development of RGCs, and whether it is required to maintain dendritic stability in adults. Thus, we will examine the roles of CD3ζ in the BCs to RGCs wiring using our newly generated molecular and genetic tools. Collectively, our studies seek to reveal the strategy and mechanisms that control RGCs type-specific circuit formation. These studies will constitute a significant step forward in understanding the mechanisms underlying the development of function-specific circuits.

哺乳动物神经系统由数十亿个神经元组成，这些神经元的精确组装 神经元进入圆圈可确保正确的功能。在视网膜中，潜水员但精确的双极线 细胞（BCS）和视网膜神经节细胞（RGC）作为视觉信号电路处理的结构基础 从外视网膜到内部视网膜。这些线路的缺陷导致严重的残留疾病。最常见的 这些疾病的例子是青光眼，该疾病对美国构成了重要的社会和经济伯恩。 人口。开发有效疗法以使BC再生为RGC接线的主要障碍是我们的贫穷 了解这些电路的结构以及确保BC和RGC的机制 恰恰。在此提案中，我们说明了功能特定BC的细胞策略至RGC接线以及CD3ζ如何 有选择地指示RGC针对布线的各种BC类型。说明函数特定的组装 电路，我们开发了一种新型的跨细胞标签技术，用于标记BCS突触特定于功能特异性 RGCS。我们在特定类型的DS-RGC（BD-RGC）上的结果与EM Connectomic的结果相当 研究。我们的结果还表明，两种不同的RGC类型具有不同BC类型的突触，这表明RGC 具有卑诗省类型的特定类型接线。这些研究使我们对更多的RGC类型进行了分配，并揭示了 引导每种RG​​C类型的各种BC类型的基础机制。为此，我们 发现CD3ζ的突变是I类主要组织相容性复合物（MHCI）的接收器，消除了突触 锥体BC与BD-RGC的连接，但增加了锥体BCS与J-RGC的合成连接，从而允许 RGC特异性突触调节。 CD3ζ突变体中BD-RGC的锥体BCS突触接线的缺陷 明显损害了BD-RGC的光诱发响应，这表明精确的BC-RGC突触连接 对于确保RGC的功能特异性是必要的。为了进一步测试这个想法，我们将确定BC类型有线 对于其他4种RGC类型和这些RGC的突触功能，以揭示负责的细胞策略 指定RGC功能。我们还将检查CD3ζ如何指导突触的形成和功能 RGCS。为了发现CD3ζ介导的合成组件的基础机制，我们表明敲低 在野生型小鼠或CD3ζ突变体的RGC中过表达CD3ζ仅在转导的RGC中诱导表型， 提出一种细胞自主机制。为了进一步扩展我们对机制的理解，我们将 执行一系列分析以确定是否需要特异性的CD3ζ进行树突发展 RGC，是否足以用于RGC的树突开发，以及是否需要维护 成年人的树突状稳定性。这是，我们将使用我们的新来检查CD3ζ在BCS中的作用与RGC接线 产生的分子和遗传工具。总体而言，我们的研究试图揭示策略和机制 该控制RGCS类型特异性电路的形成。这些研究将构成重要的一步 了解功能特定电路发展的基础机制。