Molecular mechanism of CPG15 mediated activity-dependent synaptic plasticity

CPG15介导的活性依赖性突触可塑性的分子机制

• 批准号: 10330440
• 负责人: Dalila G. Ordonez
• 金额: $ 0.56万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-01 至 2022-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10330440
• 关键词: AMPA Receptors; Acids; Affinity; Anatomy; Axon; Binding; Biological Assay; Boston; Brain; Cell surface; Co-Immunoprecipitations; Communities; Complex; Data; Data Analyses; Dendritic Spines; Development; Engineering; Environment; Event; Excitatory Synapse; Extracellular Protein; Eye; Fostering; Future; Genes; Glutamate Receptor; Glutamates; Glycosylphosphatidylinositols; Goals; Growth; Image; In Vitro; Inhibitory Synapse; Institutes; International; Investigation; Knockout Mice; Label; Lateral; Learning; Light; Link; Maps; Mediating; Mediator of activation protein; Membrane; Memory; Modeling; Molecular; Monitor; Mutate; Neurodegenerative Disorders; Neurodevelopmental Disorder; Neurons; Neurosciences; Ocular Dominance; PHluorin; Pattern; Phenotype; Physiological; Play; Postdoctoral Fellow; Postsynaptic Membrane; Process; Proteins; Proteome; Research Personnel; Resolution; Rodent; Role; Series; Signal Transduction; Site; Stimulus; Structure; Surface; Synapses; Synaptic plasticity; Testing; Time; Tissues; Training; Translating; Transmembrane Domain; Vertebral column; Visual Cortex; Visualization; Work; career; cell type; critical developmental period; density; deprivation; experience; extracellular; hippocampal pyramidal neuron; imaging system; in vitro testing; in vivo; in vivo evaluation; in vivo imaging; innovation; knock-down; link protein; live cell imaging; member; neural circuit; neuronal circuitry; post-doctoral training; postsynaptic; postsynaptic density protein; presynaptic density protein 95; prevent; protein complex; receptor; receptor binding; recruit; response; success; synaptic pruning; synaptogenesis; tool development; two-photon; visual deprivation; visual processing

): Cortical function relies on complex neuronal circuits composed of multiple cell types and millions of connecting synapses. During late development, immature cortical networks are progressively optimized via a process known as synaptic pruning. During this period, neurons are particularly sensitive to external stimuli, and activity- dependent signals guide circuit refinement through selective stabilization or elimination of specific synaptic connections. Elucidating the molecular mechanisms underlying activity-dependent synapse selection is key to understanding this fundamental aspect of brain development and plasticity. Activity-regulated genes are prime molecular applicants for mediating the effects of neuronal activity on synapse formation and elimination. One example is applicant plasticity gene 15 (CPG15), which encodes a small glycosylphosphatidylinositol (GPI)- linked protein attached to the cell surface. CPG15 has been previously implicated in axonal and dendritic growth and the maturation of excitatory synapses. New preliminary results reveal that CPG15 knockdown reduces recruitment of the postsynaptic density protein 95 (PSD95) to newly formed dendritic spines of pyramidal neurons, thus reducing spine stabilization. This finding is mechanistically puzzling given that CPG15 is extracellular while PSD95 is intracellular, and neither protein possesses a transmembrane domain. Recently, investigation of the AMPA-type glutamate receptor proteome identified CPG15 as part of the protein complex that co-precipitates with AMPA receptor subunits. To test the role of CPG15 in spine stabilization, our goal is to investigate the effect of CPG15 direct interaction with AMPA receptors to mediate the recruitment of PSD95 to newly formed excitatory synapses. With the power of combined in vitro and in vivo approaches, our data can reveal, for the first time and in unprecedented detail, the timing and sequence of AMPAR and PSD95 recruitment and shed light onto molecular signals that control the formation and continuous adaptation of neuronal networks. The in vitro and in vivo analyses of the CPG15 knockout mouse could easily be translated to a KO model for any neurodevelopmental or neurodegenerative disorder and provide crucial training in in vivo imaging, molecular tool development, and sophisticated data analysis, all applicable to my future work as an independent researcher. Training with Dr. Nedivi, my sponsor and an internationally recognized expert in the field of synaptic plasticity and in vivo 2-photon imaging, is an ideal fit for the project proposed and for my career goals as outlined in the training plan. Being an active member of the vibrant neuroscience community at MIT and Boston, will help me establish scientific relationships with leaders in the field and postdoctoral fellows who will become my colleagues in the future. The Nedivi lab, the Picower Institute for Learning and Memory, and MIT foster innovative work at the interface of neuroscience and engineering, an ideal fit for my academic growth. This outstanding postdoctoral training environment will facilitate my success in launching a career as an independent investigator.

皮质功能依赖于由多种细胞类型和数以百万计的连接突触组成的复杂神经回路。在发育后期，未成熟的皮层网络通过一个被称为突触修剪的过程逐渐优化。在此期间，神经元对外部刺激特别敏感，活动依赖信号通过选择性稳定或消除特定突触连接来指导电路优化。阐明活动依赖性突触选择的分子机制是理解大脑发育和可塑性这一基本方面的关键。活动调节基因是介导神经元活动对突触形成和消除影响的主要分子申请人。一个例子是适应性基因15 (CPG15)，它编码附着在细胞表面的小糖基磷脂酰肌醇（GPI）连接蛋白。CPG15先前与轴突和树突生长以及兴奋性突触的成熟有关。新的初步结果表明，CPG15敲低可减少锥体神经元新形成的树突棘上突触后密度蛋白95 （PSD95）的募集，从而降低脊柱的稳定性。这一发现在机制上令人费解，因为CPG15是细胞外的，而PSD95是细胞内的，两种蛋白质都不具有跨膜结构域。最近，对AMPA型谷氨酸受体蛋白质组的研究发现，CPG15是与AMPA受体亚基共沉淀的蛋白质复合物的一部分。为了测试CPG15在脊柱稳定中的作用，我们的目标是研究CPG15与AMPA受体的直接相互作用在介导PSD95向新形成的兴奋性突触募集中的作用。通过体外和体内结合的方法，我们的数据可以首次以前所未有的细节揭示AMPAR和PSD95募集的时间和序列，并揭示控制神经元网络形成和持续适应的分子信号。CPG15敲除小鼠的体外和体内分析可以很容易地转化为任何神经发育或神经退行性疾病的KO模型，并在体内成像，分子工具开发和复杂的数据分析方面提供重要的训练，这些都适用于我未来作为独立研究人员的工作。Nedivi博士是我的赞助人，也是突触可塑性和体内双光子成像领域的国际知名专家。与Nedivi博士一起培训，对于我提出的项目和培训计划中概述的职业目标来说是一个理想的选择。作为麻省理工学院和波士顿充满活力的神经科学社区的积极成员，将帮助我与该领域的领导者和博士后建立科学关系，他们将成为我未来的同事。Nedivi实验室、Picower学习与记忆研究所和麻省理工学院在神经科学和工程的界面上促进创新工作，这非常适合我的学术成长。这个优秀的博士后培养环境将有助于我成功地开启独立研究者的职业生涯。