Exploring the mechanisms of Semaphorin/Plexin-mediated synapse formation in the intact hippocampus

探索完整海马中 Semaphorin/Plexin 介导的突触形成机制

• 批准号: 10373966
• 负责人: Susannah Adel
• 金额: $ 3.54万
• 依托单位: BRANDEIS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-16 至 2023-03-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10373966
• 关键词: Adult; Affinity; Alzheimer' s Disease; Attention; Biological Assay; Brain; CD100 antigen; Cell Communication; Cell physiology; Cells; Chimera organism; Clinical; Cognition Disorders; Complex; Cytoskeletal Modeling; Data; Development; Down Syndrome; ERBB2 gene; Ephrins; Epilepsy; Excitatory Synapse; Exhibits; Extracellular Domain; Family; Genes; Glutamates; Heterodimerization; Hippocampus (Brain); Homo; Imaging technology; Inhibitory Synapse; Ion Channel Gating; Knock-out; Knockout Mice; Ligands; Link; Mediating; Mental disorders; Modeling; Molecular; Molecular Conformation; Mus; Nervous system structure; Neuraxis; Neurodegenerative Disorders; Neuroglia; Neurotransmitters; Pathway interactions; Pharmacology; Play; Process; Property; Protein Family; Proteins; RNA Interference; Receptor Protein-Tyrosine Kinases; Recombinants; Research; Rodent; Role; SEMA3F gene; Scaffolding Protein; Seizures; Semaphorins; Signal Pathway; Signal Transduction; Slice; Specific qualifier value; Synapses; Synaptic Vesicles; Testing; Time; To specify; Transgenic Mice; Transmembrane Domain; Work; autism spectrum disorder; axon guidance; cell type; density; developmental neurobiology; excitatory neuron; experimental study; forward genetics; gamma-Aminobutyric Acid; gene discovery; genetic manipulation; genome-wide; high resolution imaging; in vivo; inhibitor; inhibitory neuron; knock-down; mutant; nervous system development; novel; overexpression; plexin; postsynaptic; postsynaptic neurons; presynaptic; receptor; resilience; response; reverse genetics; synaptic function; synaptogenesis; tool

Project Summary: In the mammalian central nervous system, two main types of synapses – glutamatergic and GABAergic – play opposing roles in exciting or inhibiting the postsynaptic cell. While it is critical that upon cell-cell contact, new synapses form the correct postsynaptic specialization (excitatory or inhibitory), the molecular pathways specifying this identity remain a fundamental mystery in developmental neurobiology. This process is presumably regulated by trans-synaptic ligand/receptor partners that belong to protein families (e.g. Neuroligins/Neurexins, Ephrins/Ephs, Semaphorins/Plexins) which have been demonstrated to regulate both excitatory and inhibitory synapse formation. Semaphorins (Semas) and Plexins are families of widely expressed and functionally versatile transmembrane or secreted ligands and their transmembrane receptors that first gained attention for their roles in axon guidance during nervous system development. Class 4 Semas and Plexin-B receptors are expressed in mammalian hippocampus (in excitatory and inhibitory neurons and in glia) and promote synapse formation both during development and in adulthood. Our previous studies revealed Sema4D to be one of few molecules having synaptogenic function restricted to inhibitory synapses; the extracellular domain of Sema4D induces inhibitory synapse formation on a rapid timescale (~30 mins) through the Plexin-B1 receptor. Additionally, Sema4A promotes formation of both inhibitory and excitatory synapses in hippocampus via the Plexin-B1 or Plexin-B2 receptors, respectively. The ability to rapidly drive synapse formation by application of Sema4A or Sema4D, as well as the observations that these Semas regulate inhibitory and excitatory synapse formation in unique ways requiring different Plexin-B receptors, are central to our proposed strategy to identify the distinct signaling conformations that instruct synapse identity (excitatory or inhibitory) downstream of Plexin-B receptor engagement. Further, we previously showed that Sema4D protein application increases resilience to seizure in adult mice in vivo, a finding that supports the potential clinical impact of this work. The proposed research uses a combination of transgenic mice, organotypic hippocampal slice culture, gene knockdown, and expression of mutant forms of Plexin-B receptors to examine the divergent roles of 1) unique Plexin-B signaling domains, 2) a novel mechanism gating Plexin-B1 signaling in cis, and 3) contributions from Plexin-B coreceptors, in excitatory and inhibitory synapse formation promoted by class 4 semaphorins.

项目摘要： 在哺乳动物中心神经系统中，两种主要突触类型 - 谷氨酸和加巴能 在令人兴奋或抑制突触后细胞中的角色。 突触形成了正确的突触后专业化（兴奋或抑制），即分子途径 指定这种身份仍然是发展神经生物学的基本谜团 可以由跨突触的配体/受体定制，与蛋白质家族相关的伙伴（例如， 神经素/神经毒素，晶状体/ephs，词素/丛蛋白）已被证明可以调节这两者 精确和抑制性突触形成。 信号蛋白（SEMA）和丛蛋白是广泛表达且功能多功能的跨膜或 分泌的配体及其跨膜受体表明，对轴突指导中角色的门控注意 在神经系统的发展过程中。 海马（在兴奋性和吸入性神经元中以及在神经胶质中）并促进突触形成 发展和成年。 我们以前的研究表明，SEMA4D是少数具有突触功能的分子之一 抑制突触； 时间尺度（〜30分钟）通过plexin-b1受体。 通过plexin-b1或plexin-b2接受的抑制性和兴奋性突触 能够通过SEMA4A或SEMA4D快速驱动突触形成，以及观察 这些SEMAS以独特的方式调节抑制性和兴奋性突触形成方式，方式需要Plexin-B 受体，是我们支撑策略的核心，以确定不同的信号传导构象 指导Plexin-B受体下游的突触身份（兴奋性或入侵） 参与。 体内成年小鼠癫痫发作的弹性，这一发现支持了潜在的临床影响 这项工作。 支撑研究结合了转基因小鼠，器官型海马切片培养，基因。 敲低和丛集受体突变形式的表达，以检查1）独特的作用。 plexin-b信号域，2）一种新型的机制门控在顺式中的机制，以及3） PLEXIN-B核心，在4类信号素促进的兴奋性和吸入性突触形成中。