Nanoscale organization of the inhibitory synapse during synaptic plasticity

突触可塑性过程中抑制性突触的纳米级组织

• 批准号: 10453907
• 负责人: Katharine Rachel Smith
• 金额: $ 7.77万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-12-01 至 2024-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10453907
• 关键词: Architecture; Behavior; Brain; Brain Diseases; Cognition; Disease; Disease model; Equilibrium; Future; Goals; Growth; Imaging Techniques; Inhibitory Synapse; Interneurons; Learning; Lighting; Location; Mediating; Memory; Microscopy; Molecular; Neuraxis; Neurons; Pathology; Regulation; Resolution; Site; Slice; Stroke; Structure; Synapses; Synaptic plasticity; Testing; Time; Work; autism spectrum disorder; gephyrin; nanoscale; nervous system disorder; neuronal circuitry; neuronal excitability; novel; novel therapeutic intervention; postsynaptic; presynaptic; receptor; scaffold; synaptic function; synaptic inhibition

Project Summary The correct balance between excitation and inhibition (E/I balance) in neuronal circuits is essential for learning and memory, cognition and behavior. Disrupted inhibition leading to elevated neuronal and circuit excitability is thought to underlie the pathology of numerous neurological disorders, therefore a comprehensive understanding of the molecular mechanisms involved in synaptic inhibition will have the potential to direct new therapeutic strategies for treating these conditions. GABAergic inhibitory synapses mediate the majority of synaptic inhibition in the central nervous system, and their plasticity controls neuronal excitability and function. The number of GABAA receptors (GABAARs) at inhibitory postsynaptic sites is a key determinant of inhibitory synapse strength and hence neuronal inhibition. Therefore defining mechanisms by which synaptic GABAARs are clustered and how they are altered in synaptic plasticity is imperative for understanding inhibition and its disruption in brain disorders. Using the versatile super-resolution imaging technique, Structured Illumination Microscopy (SIM), we find that GABAARs and their scaffold, gephyrin, form nanoscale subsynaptic domains (SSDs) in the inhibitory postsynaptic domain, are modulated during plasticity, and form closely associated pairs with presynaptic release SSDs in the active zone, suggesting that a modular nanoscale architecture for the inhibitory synapse may be important for their plasticity and function. Our goal is to determine the mechanisms that control inhibitory nanoscale organization, understand how this organization influences inhibitory synaptic function and is altered during synaptic plasticity, and determine how these facets differ between diverse inhibitory synapse subtypes. This proposal will (1) determine the mechanisms underlying the formation of postsynaptic inhibitory SSDs during activity-dependent synapse growth, (2) define the mechanisms and functional relevance of postsynaptic SSD clustering opposite presynaptic release sites, and (3) examine how subcellular location and interneuron input influence inhibitory nanoscale organization. These aims will test our overarching hypothesis that inhibitory synaptic nanoscale organization underlies inhibitory synaptic strength, and its dynamic regulation is a crucial mechanism for synaptic plasticity. These proposed studies will be significant, being the first comprehensive mechanistic and functional examination of inhibitory synapse architecture at nanoscale resolution (in both culture and slice) and in real-time during short- and long-term plasticity paradigms. The widespread importance of this work is that it will greatly expand our understanding of the detailed mechanisms that control inhibitory synaptic plasticity and inhibition, which is critical for maintaining E/I balance and neuronal function. Moreover, determining the nanoscale structure of inhibitory synapses in healthy brains will pave the way for future studies in disease models to provide novel understanding of how inhibitory synapse structure, function and E/I balance are disrupted in neuropathological disorders.

项目摘要 神经元回路中兴奋和抑制之间的正确平衡(E/I平衡)对学习至关重要 以及记忆、认知和行为。干扰抑制导致神经元和回路兴奋性升高 被认为是许多神经疾病的病理基础，因此 对涉及突触抑制的分子机制的理解将有可能指导新的 治疗这些疾病的治疗策略。GABA能抑制性突触介导大部分 中枢神经系统中的突触抑制，其可塑性控制神经元的兴奋性和功能。 抑制性突触后部位的GABAA受体(GABAAR)的数量是抑制性的关键决定因素 突触强度，因此神经元抑制。因此定义了突触GABA受体的机制 以及它们在突触可塑性中是如何改变的，这对于理解抑制及其 大脑紊乱中的干扰。使用多功能的超分辨率成像技术，结构照明 显微镜下(SIM)，我们发现GABAARs和它们的支架--吉普林形成了纳米级的突触亚域 (SSD)位于抑制性突触后区域，在可塑性过程中受到调制，并形成紧密关联的对 随着突触前释放SSD在活动区，表明模块化的纳米级架构 抑制性突触可能对它们的可塑性和功能起重要作用。我们的目标是确定 控制抑制性纳米组织，了解这种组织如何影响抑制性突触 功能，并在突触可塑性过程中被改变，并确定这些方面在不同的 抑制性突触亚型。这一提议将(1)确定形成的机制 活性依赖的突触生长过程中的突触后抑制SSD，(2)定义机制和 突触后SSD聚集相对突触前释放部位的功能相关性，以及(3)检查如何 亚细胞定位和神经元间输入影响抑制性纳米结构。这些目标将考验我们的 压倒一切的假设认为，抑制性突触的纳米级组织是抑制性突触强度的基础， 其动态调节是突触可塑性的重要机制。这些拟议的研究将是 意义重大，首次对抑制性突触进行全面的机制和功能检查 纳米级分辨率(培养和切片)的体系结构以及在短期和长期期间的实时 可塑性范式。这项工作的广泛重要性在于，它将极大地扩大我们对 控制抑制突触可塑性和抑制的详细机制，这是维持突触可塑性的关键 E/I平衡与神经元功能。此外，确定抑制性突触的纳米级结构 健康的大脑将为未来在疾病模型中的研究铺平道路，以提供对如何 在神经病理障碍中，抑制性突触的结构、功能和E/I平衡被破坏。