SynDIG1/Prrt1 regulation of extrasynaptic GluA1-containing AMPARs during plasticity

SynDIG1/Prrt1 在可塑性过程中对突触外含 GluA1 AMPAR 的调节

• 批准号: 10656455
• 负责人: ELVA D DIAZ
• 金额: $ 62.53万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-24 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10656455
• 关键词: AMPA Receptors; Acute; Address; Age; Alzheimer' s Disease; Biological Assay; Brain; Brain Diseases; Cell surface; Cells; Chemicals; Cognitive; Color; Complex; DLG4 gene; Data; Defect; Dissociation; Down-Regulation; Drug Targeting; Electrophysiology (science); Epilepsy; Etiology; Exhibits; Family; Genes; Glycine; Hippocampus; Image; Integral Membrane Protein; Investigation; Knock-out; Knockout Mice; Knowledge; Label; Learning; Long-Term Depression; Long-Term Potentiation; Maintenance; Mediating; Membrane Proteins; Memory; Mental Depression; Mental disorders; Methods; Microscopy; Modeling; Molecular; Mus; N-Methylaspartate; Nervous System; Neurons; PHluorin; Permeability; Postsynaptic Membrane; Proline; Proteins; Proteomics; Regulation; Role; Schizophrenia; Seizures; Site; Slice; Stimulus; Stroke; Surface; Synapses; Synaptic Receptors; Synaptic Transmission; Synaptic plasticity; Testing; Tetanus; Up-Regulation; Variant; Viral; Visualization; Wild Type Mouse; Work; cognitive skill; density; domain mapping; drug development; in vivo; insight; interdisciplinary approach; knock-down; morris water maze; mutant; nervous system disorder; neural network; neuromechanism; neuron loss; neurotransmission; novel; object recognition; postsynaptic; pre-clinical; receptor; receptor function; recruit; synaptic depression; ultra high resolution

Activity-dependent variation in synaptic AMPA receptor (AMPAR) content, referred to as ‘synaptic plasticity’, is a mechanism whereby information is stored in neural networks that give rise to higher order cognitive skills such as learning and memory. During long-term potentiation (LTP), a widely studied form of synaptic plasticity, extrasynaptic AMPARs are recruited from nearby reserve pools, including perisynaptic regions on the cell surface and intracellular compartments, and subsequent anchored with the postsynaptic density (PSD). A large body of evidence spanning decades of investigation has established mechanisms by which AMPARs are anchored within the PSD. In contrast, the molecular mechanisms that govern AMPAR synaptic targeting to establish reserve pools of extrasynaptic receptors are largely unknown. Given that recruitment of reserve pools of extrasynaptic AMPARs underlies the rapid strengthening of synapses that occurs during LTP, the molecular mechanisms that establish such reserve pools are critical to our understanding of synaptic plasticity and represent a major gap in our knowledge. SynDIG (Synapse Differentiation Induced Gene) defines a family of four genes (SynDIG1-4) that encode brain- specific transmembrane proteins. Here we will determine the function of SynDIG4 (SD4), also known as Prrt1 (Proline-rich transmembrane protein 1) in the regulation of the reserve pool of AMPARs. Proteomic studies indicate that SD4 is a component of AMPAR complexes; however, SD4 is not enriched in the PSD, but instead colocalizes with GluA1-containing AMPARs at non-synaptic sites. Remarkably, tetanus-induced LTP, which is dependent on GluA1, is abolished in acute hippocampal slices from SD4 knockout (KO) while theta-burst stimulation LTP (TBS-LTP), which is independent of GluA1, is not impaired. Furthermore, SD4 KO mice exhibit profound deficits in two independent cognitive assays (Morris water maze, novel object recognition), demonstrating a critical role for SD4 in hippocampal-dependent learning and memory. Moreover, extrasynaptic AMPARs are reduced in SD4 KO compared with wild-type (WT) neurons. Given that reserve pools of extrasynaptic AMPARs are critical for synaptic plasticity, we hypothesize that SD4 maintains such reserve pools of extrasynaptic GluA1-containing AMPARs that are deployed during tetanus-induced LTP. In this collaborative dual-PI application we propose a comprehensive multidisciplinary approach to investigate SD4-dependent regulation of extrasynaptic GluA1-containing AMPARs with molecular, cellular, and electrophysiological methods. In Aim 1 we will define the mechanism by which SD4 maintains extrasynaptic GluA1-containing AMPARs. In Aim 2 we will determine whether synaptic targeting of reserve pools of GluA1- containing AMPARs during plasticity requires SD4. In Aim 3 we will test whether homomeric GluA1-dependent synapse plasticity mechanisms require SD4 ex vivo at multiple ages. The results of these studies will provide molecular insight into fundamental mechanisms that govern establishment and maintenance of the reserve pools of extrasynaptic AMPARs critical for synaptic plasticity and address a major gap in our knowledge.

突触AMPA接收器（AMPAR）含量的活动依赖性变化，称为“突触可塑性” 信息在神经网络中存储的机制，引起高阶认知技能 例如学习和记忆。在长期增强期间（LTP），这是一种广泛研究的突触可塑性形式， 在附近的储备池中招募了外突触的AMPAR，包括细胞上的塞突触区域 表面和细胞内室，随后以突触后密度（PSD）锚定。一个大 跨越数十年调查的证据体已经建立了AMPAR的机制 锚定在PSD中。相反，控制AMPAR突触靶向的分子机制 建立外部挑战受体的储备池在很大程度上是未知的。鉴于招募储备池 外突触的基础是LTP期间发生的突触的快速加强 建立此类储备池的机制对于我们对突触可塑性的理解至关重要 在我们的知识上代表了一个主要差距。 syndig（突触分化诱导的基因）定义了四个基因（Syndig1-4）的家族，该家族编码脑 特定的跨膜蛋白。在这里，我们将确定Syndig4（SD4）的功能，也称为PRRT1 （富含脯氨酸的跨膜蛋白1）在AMPAR储备库的调节中。蛋白质组学研究 表明SD4是AMPAR复合物的组成部分。但是，SD4在PSD中不丰富，而是 与非突触部位的含GLUA1的AMPAR共定位。值得注意的是，Tetanius引起的LTP， 取决于GLUA1，在SD4敲除（KO）的急性海马切片中废除，而Theta-Burst 刺激LTP（TBS-LTP）与GLUA1无关。此外，SD4 KO小鼠展出 深刻的定义了两个独立的认知测定法（莫里斯水迷宫，新颖的对象识别）， 证明SD4在海马依赖性学习和记忆中的关键作用。此外，外突触 与野生型（WT）神经元相比，SD4 KO中的AMPAR降低。鉴于那个储备池 外鼻室对突触可塑性至关重要，我们假设SD4维护此类储备池 在Tetanius诱导的LTP期间部署的含外抗gluA1的AMPAR。 在此协作双PI应用程序中，我们提出了一种全面的多学科方法来调查 SD4依赖性调节与分子，细胞和细胞和细胞的含外抗glua1的AMPAR 电生理方法。在AIM 1中，我们将定义SD4维持外突触的机制 含GLUA1的AMPAR。在AIM 2中，我们将确定是否将突触靶向Glua1-的储备库 - 在可塑性期间包含AMPAR需要SD4。在AIM 3中，我们将测试是否依赖于GluA1 突触塑性机制需要多个年龄的SD4离体。这些研究的结果将提供 分子洞悉管理和维护储量的基本机制 突触外的AM比对突触可塑性至关重要，并解决了我们所知的主要差距。