Molecular mechanisms of excitatory postsynaptic diversity

兴奋性突触后多样性的分子机制

• 批准号: 10542808
• 负责人: JASON P WEICK
• 金额: $ 37.88万
• 依托单位: UNIVERSITY OF NEW MEXICO HEALTH SCIS CTR
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-01 至 2025-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10542808
• 关键词: AMPA Receptors; Active Biological Transport; Acute; Address; Affect; Affective; Animals; Behavior; Behavioral; Brain; Cell surface; Cells; Chronic; Cultured Cells; Data; Dendritic Spines; Development; Disparate; Elements; Excitatory Synapse; Family; Family member; Gene Family; Genes; Glutamates; Goals; Hippocampus; Image; In Vitro; Individual; Integral Membrane Protein; Knock-out; Knockout Mice; Knowledge; Label; Long-Term Potentiation; Maintenance; Mental Depression; Molecular; Molecular Profiling; Morphology; Motor; Neurons; Pathway interactions; Pattern; Physiological; Play; Population; Post-Translational Protein Processing; Preparation; Presynaptic Terminals; Process; Property; Proteins; Proteome; Publishing; Regulation; Role; Scaffolding Protein; Second Messenger Systems; Shapes; Signaling Protein; Site; Slice; Stimulus; Surface; Synapses; Synaptic plasticity; Techniques; Time; Vesicle; Work; anxiety-like behavior; behavior test; cognitive function; ex vivo imaging; experience; fear memory; information processing; knockout animal; member; nerve supply; neural network; novel; outcome disparities; overexpression; postsynaptic; postsynaptic neurons; protein expression; protein transport; receptor expression; recruit; response; subcellular targeting; synaptic function; trafficking

Unique patterns of synaptic connectivity between neurons, and the differential strength of those synapses, are fundamental to the information processing capability of the brain. Synaptic strength is determine by the number, composition, and post-translational modifications of post-synaptic AMPA receptors (AMPARs). These features of AMPARs are regulated by a host of second messenger pathways, scaffolding proteins, and trafficking proteins in post-synaptic densities (PSDs). For synapses that display primarily postsynaptic plasticity, the proteins responsible for regulating AMPAR surface expression are thought to be shared across glutamatergic PSDs. Thus, it remains unknown whether fundamental differences in synaptic strength between synapses exist due to unique protein signatures of individual PSDs. Neuron-specific genes (NSG1-3) encode single transmembrane proteins involved in the secretory trafficking of multiple scaffold and signaling proteins, including postsynaptic AMPARs. Studies in cultured cells as well as acute hippocampal slice preparations have established that disrupting NSG1-3 function independently causes severe alterations in basal synaptic activity and plasticity. Interestingly, our published and preliminary evidence show that NSG1 and NSG2 chronically reside within a subset of synapses in excitatory hippocampal neurons. In addition, our data show that knockout (KO) of these proteins differentially affects network function and induces behavioral deficits. This study will be significant because it will identify whether multiple members of the NSG family are restricted to a unique subpopulation of excitatory synapses, and confer unique functional properties via the promotion of AMPAR surface expression. We will use a combination of validated and novel techniques to address these important questions in three specific aims: Specific Aim 1. Determine whether NSG proteins define unique population(s) of excitatory synapses. We will use in vitro time lapse, and ex vivo imaging to determine whether NSG1 and NSG2 are specifically targeted to a subset of hippocampal synapses or trafficked between them. Specific Aim 2. Determine whether individual NSG proteins differentially affect synaptic function. Using physiological recordings and glutamate uncaging we will determine whether NSG1/2 are differentially involved in promoting surface AMPAR expression during basal or activity-dependent conditions. Specific Aim 3: Determine whether KO of NSG proteins leads to specific, dissociable behavioral deficits. Using established and novel behavioral tests in single and double KO mice we will determine whether NSG1/2 proteins play unique or overlapping roles in shaping motor, affective, and cognitive function in live animals.

神经元之间突触连接的独特模式以及这些突触的差异强度是 大脑信息处理能力的基础。突触强度由数量决定， 突触后 AMPA 受体 (AMPAR) 的组成和翻译后修饰。这些功能 AMPAR 受到许多第二信使途径、支架蛋白和运输蛋白的调节 突触后密度（PSD）。对于主要表现出突触后可塑性的突触，蛋白质 负责调节 AMPAR 表面表达的蛋白被认为是谷氨酸能 PSD 所共有的。 因此，目前尚不清楚突触之间的突触强度是否存在由于以下原因而存在的根本差异： 各个 PSD 的独特蛋白质特征。神经元特异性基因 (NSG1-3) 编码单跨膜 参与多种支架和信号蛋白分泌运输的蛋白质，包括突触后蛋白 AMPAR。对培养细胞以及急性海马切片制剂的研究已经证实： 破坏 NSG1-3 功能会独立导致基础突触活动和可塑性的严重改变。 有趣的是，我们发表的初步证据表明 NSG1 和 NSG2 长期存在于一个 兴奋性海马神经元中的突触子集。此外，我们的数据显示，这些 蛋白质对网络功能有不同的影响并诱发行为缺陷。这项研究将具有重大意义 因为它将确定 NSG 家族的多个成员是否仅限于一个独特的亚群 兴奋性突触，并通过促进 AMPAR 表面表达赋予独特的功能特性。 我们将结合使用经过验证的新技术和新颖的技术来解决三个重要问题 具体目标： 具体目标 1. 确定 NSG 蛋白是否定义了独特的兴奋性突触群体。 我们将使用体外延时和离体成像来确定 NSG1 和 NSG2 是否具有特异性 针对海马突触的子集或在它们之间运输。 具体目标 2. 确定各个 NSG 蛋白是否对突触功能有不同的影响。 使用生理记录和谷氨酸解禁，我们将确定 NSG1/2 是否存在差异 参与在基础或活性依赖性条件下促进表面 AMPAR 表达。 具体目标 3：确定 NSG 蛋白的 KO 是否会导致特定的、可分离的行为缺陷。 使用单和双 KO 小鼠中已建立的和新颖的行为测试，我们将确定 NSG1/2 是否 蛋白质在塑造活体动物的运动、情感和认知功能方面发挥着独特或重叠的作用。