Mechanisms Underlying Type II Cadherin Guided Assembly of Retinal Circuits

II 型钙粘蛋白引导视网膜电路组装的潜在机制

• 批准号: 9886125
• 负责人: Xin Duan
• 金额: $ 40.25万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9886125
• 关键词: Address; Adopted; Anatomy; Atlases; Axon; Biological Assay; Biological Models; Bipolar Neuron; Brain; Brain region; Cadherins; Cell Adhesion Molecules; Cell Communication; Cells; Chimeric Proteins; Clustered Regularly Interspaced Short Palindromic Repeats; Code; Complex; Defect; Detection; Development; Disease; Ensure; Etiology; Eye; Eye diseases; Family; Genes; Genetic; Genetic Techniques; Goals; Individual; Injections; Interneurons; Knowledge; Lead; Location; Logic; Mediating; Methods; Molecular; Molecular Profiling; Nervous system structure; Neuraxis; Neurites; Neurons; Nose; Pattern; Physiological; Positioning Attribute; Process; Proteins; Retina; Retinal Ganglion Cells; Role; Series; Signal Transduction; Specific qualifier value; Specificity; Structure; Study models; Synapses; System; Testing; To specify; Translating; Vision; Visual; axon guidance; base; combinatorial; differential expression; experimental study; extracellular; gain of function; ganglion cell; genetic approach; in utero; in vivo; innovation; insight; mutant; nervous system disorder; neural circuit; neurodevelopment; neuronal patterning; novel; postsynaptic; relating to nervous system; retinal neuron; segregation; starburst amacrine cell; synaptogenesis; tool; visual information

In the eye, complex retinal circuits are wired together for precise neural computation. The diverse but precise wiring between interneurons and retinal ganglion cells serve as the structural basis for circuit processing of different visual features. These parallel circuits are wired up precisely, as defects may lead to several eye diseases and neurological disorders. To investigate the mechanisms behind how diverse neuronal types precisely integrate into distinct parallel retinal circuits, we developed methods that allow for targeted genetic access of the unique On-Off direction-selective circuit, which conveys direction-selectivity signals, as the ideal model system. Our previous studies now position us to examine the role of Type II Cadherins (Cdhs) in assembling this circuit as individual proteins or in combinations. We showed that two Cdhs, Cdh9 and Cdh8, instruct parallel ON and OFF bipolar cell input to ON vs. OFF sublaminae of the ON-OFF direction-selective circuit, thus allowing precise segregation of ON and OFF channels. However, the molecular mechanisms underlying this assembly remain elusive. To investigate the molecular mechanisms underlying the differential functions of Cdh9 vs. Cdh8, we will perform a series of anatomical and functional analyses. We will identify the specific portion of the cadherin molecule, extracellular versus intracellular domains, that are responsible for their distinct functions, as well as the specific timing of their actions in forming synapses between bipolar cells and ganglion cells. We also found that Cdh9 from bipolar neurons heterophilically recognizes the two closely-related Cdhs, Cdh6 and Cdh10, from postsynaptic Ventral-pointing ON-OFF direction-selective ganglion cells (ooDSGCs) and starburst amacrine cells (SACs). We will use this established genetic system to reveal how combinatorial Cdhs act together to wire up parallel direction-selective circuits. We will examine genetically and functionally how Cdh6-9-10 single, double, and triple combinations pattern the Ventral-ooDSGC interaction with SACs. To further expand our understanding of the combinatorial cadherin code in neuronal patterning, we will test the role of Cdh11, which is identified as a Nasal-pointing ooDSGC enriched gene through molecular profiling. Thus, we will generate new molecularly and genetically targeted methods to examine the roles of Cdh11 and its closely related Cdh8 in the wiring of Nasal-pointing direction-selective circuits. Furthermore, we established an in utero injection system to ectopically introduce individual Type II Cdhs onto Ventral-ooDSGCs or Nasal-ooDSGCs to pinpoint combinatorial Cdhs in regulating DS-circuit patterning. Collectively, our studies seek to reveal how Cdh combinations control the formation of parallel but distinct DS circuits. Comprehensive studies on Type II Cdh function would be a major advance for a long-standing question in mammalian neural development. These studies will be a major step forward in understanding how multiple genes interact to specify the wiring of complex neural circuits. The identified mechanisms will have significant relevance to selective circuit wiring throughout the central nervous system.

在眼中，复杂的视网膜电路被连接在一起以进行精确的神经计算。多样但精确的 中间神经元和视网膜神经节细胞之间的接线是电路处理的结构基础 不同的视觉特征。这些平行电路是精确接线的，因为缺陷可能导致几只眼睛 疾病和神经系统疾病。研究如何多样化的神经元类型背后的机制 精确地整合到不同的平行视网膜电路中，我们开发了允许靶向遗传的方法 访问唯一传达方向选择信号的唯一开关方向选择电路是理想的 模型系统。我们以前的研究现在将我们定位为检查II型钙粘蛋白（CDH）在 将该电路作为单个蛋白质或组合组合组装。我们证明了两个CDHS CDH9和CDH8， 指示平行于打开和关闭双极单元的输入到ON vs. Off On-Off On-Off Subliended选择性的sublaminae 电路，从而可以精确的开口和关闭通道的分离。但是，分子机制 该大会的基础仍然难以捉摸。研究差异差异的分子机制 CDH9与CDH8的功能，我们将执行一系列解剖和功能分析。我们将确定 钙粘蛋白分子的特定部分，细胞外与细胞内结构域，这些部分负责 它们的独特功能以及其在双极细胞之间形成突触时作用的特定时间 和神经节细胞。我们还发现，来自双极神经元的CDH9异质上识别出两个密切相关的CDHS CDH6和CDH10，来自突触后腹侧腹侧开关式神经节细胞。 （OODSGCS）和Starburst Amacrine细胞（SACS）。我们将使用这个既定的遗传系统来揭示如何 组合CDH共同作用以连接并行方向选择电路。我们将从遗传和 在功能上，CDH6-9-10如何单，双重和三组合模式腹侧 - 辅助相互作用 与囊。为了进一步扩展我们对神经元模式中组合钙粘蛋白代码的理解，我们 将测试CDH11的作用，CDH11被识别为通过分子富含基因的鼻腔指向OODSGC 分析。因此，我们将生成新的分子和遗传靶向方法，以检查 CDH11及其在鼻孔方向选择电路的接线中密切相关的CDH8。此外，我们 建立了一个在子宫内注射系统，以异位将单个II型CDH引入腹侧 - 辅助工具或鼻腔内OODSGC，以在调节DS电路模式下查明组合CDH。共同 我们的研究试图揭示CDH组合如何控制平行但DS电路的形成。 关于II型CDH功能的全面研究将是一个长期存在的问题的重大进步 哺乳动物神经发育。这些研究将是理解多重多重的重要一步 基因相互作用以指定复杂神经回路的接线。确定的机制将具有重要的 与整个中枢神经系统的选择性电路接线相关。