Molecular Mechanisms Regulating Inhibitory Circuitry in the Spinal Cord

调节脊髓抑制电路的分子机制

基本信息

批准号：
10413154
负责人：
Julia Anna Kaltschmidt
金额：
$ 36.26万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-07-01 至 2024-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10413154
关键词：
Adhesions Adhesives Afferent Neurons Anatomy Animal Behavior Attenuated Axon Binding Biological Assay Cell Adhesion Cell Adhesion Molecules Cholera Toxin Protomer B Coupled Development Disease Distal Dyes Electrophysiology (science)Extensor Flexor Foundations Functional disorder Generations Goals Health In Vitro Individual Injections Injury Interneurons Knowledge Label Limb structure Measures Mediating Medical Methodology Mission Molecular Motor Motor Neurons Mus Muscle Muscle function Neuraxis Neurodegenerative Disorders Neurologic Neurons Neurotrophin 3 Phenotype Physiological Process Proprioceptor Proteins Public Health Reporter Research Role Schizophrenia Science Sensory Signal Transduction Specificity Spinal Spinal Cord Spinal cord injury Synapses Tamoxifen Testing Tracer United States National Institutes of Health Work contactin density differential expression effective therapy experimental study fluorophore improved in vivo innovation knowledge base mouse genetics nervous system disorder neural circuit neuronal circuitry neuropsychiatry neurotransmitter release presynaptic protein complex receptor relating to nervous system sensory input synaptogenesis targeted treatment

项目摘要

Establishing specific neuronal circuits is fundamental for the generation of coordinated muscle function. However, the signals underlying the specificity of connection between interneurons and their targets in the mammalian central nervous system (CNS) remain largely unknown to date. Our long-term research goal is to understand the rules of interneuron circuit wiring and the molecular mechanisms that control it. The objective of the proposed research is to describe how a combination of adhesive and neurotrophic signals determine GABAergic interneuron circuit connectivity. A class of GABAergic interneurons, termed GABApre, forms synaptic contacts with the terminals of proprioceptive sensory afferents, and thus directly controls proprioceptive sensory input through an inhibitory strategy known as presynaptic inhibition. We will test the hypothesis that the connectivity of a class of spinal GABAergic neurons varies between functionally-distinct sensory neurons and that this connectivity is mediated via (ii) differential expression of muscle-derived neurotrophin (NT)-3 and (ii) a matrix of IgSF adhesion proteins. The rationale underlying this proposal is that through understanding the mechanisms underlying GABAergic interneuron circuit formation, we will enhance our understanding of — and ultimately control over — inhibitory neuronal circuit development and function in vivo. We will test our hypothesis with the following three aims: #1) Determine the functional specificity of GABAergic interneuron circuitry; #2) Investigate the influence of muscle-derived NT-3 on GABApre synapse formation; and #3) Assess the role of Contactin-5 in GABApre-sensory synapse formation. In the first aim, we combine timed tamoxifen injections, mouse genetics and CTb labeling to analyze whether the specific connectivity of individual GABApre interneurons may be functionally relevant. In the second aim, we examine the expression of Gabrg1 in functionally distinct proprioceptive sensory neurons and assess consequences of changing NT-3 levels on both Gabrg1 expression and GABApre terminal number. In the third aim, we perturb cell adhesion signaling using mouse genetics and perform phenotypic analysis using molecular, micro-anatomic and functional assays, including an electrophysiological measure of presynaptic inhibition. We also use an in vitro binding assay to screen for new adhesion molecule candidates relevant for GABApre synaptic specificity in vivo. The research proposed in this application is innovative because it combines a molecularly-defined interneuronal circuit with a unique constellation of methodologies to integrate functional specificity with target-derived signals. The research will provide an understanding of functional diverse GABApre circuitry and also advance our understanding of how basic circuit paradigms may be adapted for diverse motor functions. The proposed work is significant because it will contribute to fundamental knowledge of the formation of circuit-level mechanisms and neural strategies used in the CNS; this in turn will advance our efforts to develop effective therapies to rebuild circuitry and muscle function after spinal cord injury or other neurological diseases.

建立特定的神经回路是产生协调的肌肉功能的基础。然而，中间神经元与其目标之间的连接特异性背后的信号迄今为止，我们对哺乳动物中枢神经系统（CNS）的了解仍然很大程度上未知。了解中间神经元电路布线的规则以及控制它的分子机制。拟议的研究旨在描述粘附信号和神经营养信号的组合如何决定 GABA 能中间神经元回路连接一类 GABA 能中间神经元，称为 GABA pre，形成突触。与本体感觉传入神经末梢接触，从而直接控制本体感觉通过称为突触前抑制的抑制策略输入我们将检验以下假设：一类脊髓 GABA 能神经元的连接在功能不同的感觉神经元和这种连接是通过 (ii) 肌肉源性神经营养素 (NT)-3 的差异表达和 (ii) 该提议的基本原理是通过了解 IgSF 粘附蛋白的矩阵。 GABAergic 中间神经元回路形成的机制，我们将增强我们对 - 和最终控制——抑制性神经回路的发育和体内功能我们将检验我们的假设。具有以下三个目标：#1) 确定 GABA 能中间神经元电路的功能特异性；#2) 研究肌肉来源的 NT-3 对 GABA 前突触形成的影响；#3) 评估 Contactin-5 在 GABA 前感觉突触形成中的作用第一个目标是结合定时注射他莫昔芬，小鼠遗传学和 CTb 标记来分析个体 GABApre 的特异性连接是否中间神经元可能具有功能相关性。在第二个目标中，我们检查了 Gabrg1 的表达。功能上不同的本体感觉感觉神经元，并评估改变 NT-3 水平对两者的影响 Gabrg1 表达和 GABApre 末端数量在第三个目标中，我们使用干扰细胞粘附信号传导。小鼠遗传学并使用分子、显微解剖和功能分析进行表型分析，包括突触前抑制的电生理学测量。我们还使用体外结合测定。筛选与体内 GABApre 突触特异性相关的新粘附分子候选物。本申请中提出的方法具有创新性，因为它将分子定义的中间神经元电路与该研究将功能特异性与目标衍生信号相结合的独特方法论。将提供对功能多样的 GABApre 电路的理解，并加深我们对基本电路范式如何适应不同的运动功能所提出的工作意义重大。因为它将有助于电路级机制和神经元形成的基础知识中枢神经系统中使用的策略；这反过来将推动我们开发有效疗法来重建回路的努力以及脊髓损伤或其他神经系统疾病后的肌肉功能。