Molecular mechanisms underlying cortical interneuron synaptic specificity

皮质中间神经元突触特异性的分子机制

• 批准号: 10558671
• 负责人: HIROKI TANIGUCHI
• 金额: $ 38.23万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-15 至 2025-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10558671
• 关键词: Address; Adhesions; Automobile Driving; Axon; Binding; Biological Assay; Brain; Brain Diseases; Brain Injuries; Cells; Data; Development; Disease; Ectopic Expression; Electroporation; Ensure; Epilepsy; Equilibrium; Etiology; Functional disorder; Gene Expression; Gene Transfer; Generations; Goals; Individual; Interneurons; Knock-out; Knockout Mice; Location; Medial; Mediating; Modeling; Molecular; Morphology; Mus; Neurons; Phenotype; Physiology; Play; Prefrontal Cortex; Presynaptic Terminals; Property; Proteins; Role; Schizophrenia; Series; Shapes; Signal Transduction; Specificity; Synapses; System; Testing; Therapeutic; Transplantation; Viral Genes; autism spectrum disorder; cell type; experimental study; genome editing; hippocampal pyramidal neuron; in vivo; insight; malformation; mouse genetics; neurofascin; novel; permissiveness; postsynaptic neurons; presynaptic; presynaptic neurons; receptor; repaired; stereotypy; success; synaptogenesis

Project Summary/Abstract Cortical inhibitory GABAergic interneurons (INs), which develop intricate local circuits, critically regulate higher- order brain functions by balancing and shaping neuronal activity. Consistent with its indispensable role in normal brain functions, malformation/malfunction of the inhibitory system is implicated in a wide array of brain disorders such as schizophrenia, autism, and epilepsy. Despite their importance, the molecular mechanisms underlying the wiring of IN local circuits remain largely unknown. Cortical INs comprise diverse cell types that are defined by morphology, physiology, and gene expression. Notably, different IN subtypes also show distinct synaptic specificity at laminar/cellular as well as subcellular levels. Although subtype-specific synaptic connectivity is considered a critical property of INs to ensure functional diversity of the inhibitory system, the molecular mechanisms underlying IN synaptic specificity remains poorly understood. The objective of this proposal is to determine the molecular mechanisms by which IN subtypes establish layer/cell type- and subcellular domain-specific synapses. To achieve this goal, we will perform a series of experiments using chandelier cells (ChCs), which exclusively innervate axon initial segments (AISs) of layer-specific pyramidal neurons (PNs). The ChC is known to critically regulate PN spike generation and has been implicated in schizophrenia and epilepsy. Besides their functional significance, the stereotypy of their synaptic organization make ChCs an attractive model to study the molecular mechanisms for IN synaptic specificity. Our preliminary data has shown that: (1) IgSF11 proteins that are known to bind with each other are expressed in both ChCs and layer-specific target PNs, (2) Gldn proteins that are known to bind to AIS-enriched proteins, NF186, are preferentially expressed in ChCs, (3) IgSF11 in ChCs plays an essential role in their presynaptic development, (4) Gldn and NF186 appear to play a role in initiating ChC synapses, and (5) IgSF11 that is free from the Gldn-NF186 system appears not to induce ChC synapses. Based on our findings, we propose to test the hypothesis that the layer-specific synaptogenic action and the subcellular domain-specific recognition mediated through IgSF11 homophilic interactions and Gldn-NF186 interactions, respectively, cooperatively determine ChC synaptic specificity. We will pursue the following specific aims to test our hypothesis. In Aim 1, we will determine the role of the IgSF11 homophilic interaction between pre- and postsynaptic neurons in layer-specific synapse formation by ChCs. In Aim 2, we will determine the role of Gldn and NF186 in ChC synapse formation on AISs. In Aim 3, we will determine the regulatory role of NF186/Gldn in gating IgSF11 signaling to induce ChC presynaptic boutons at AISs. Upon completion of this study, we will gain not only important insights into molecular mechanisms for IN wiring but also a clue to developing therapeutic strategies to functionally repair disordered/damaged brains.

项目概要/摘要 皮质抑制性 GABA 能中间神经元 (IN) 形成复杂的局部回路，关键性地调节高级 通过平衡和塑造神经元活动来调节大脑功能。与其不可或缺的作用相一致 正常的大脑功能，抑制系统的畸形/故障与大脑的多种功能有关 精神分裂症、自闭症和癫痫等疾病。尽管它们很重要，但分子机制 IN 本地电路的布线背后仍然很大程度上未知。皮质 IN 包含多种细胞类型 由形态学、生理学和基因表达来定义。值得注意的是，不同的 IN 亚型也表现出不同的 层/细胞以及亚细胞水平的突触特异性。尽管亚型特异性突触 连接性被认为是 IN 的一个关键特性，以确保抑制系统的功能多样性， IN 突触特异性的分子机制仍然知之甚少。此举的目的 建议是确定 IN 亚型建立层/细胞类型的分子机制 - 和亚细胞域特异性突触。为了实现这个目标，我们将进行一系列的实验 使用枝形吊灯细胞（ChCs），它专门支配特定层的轴突初始段（AIS） 锥体神经元（PN）。众所周知，ChC 严格调节 PN 尖峰的产生，并已被牵涉其中 用于精神分裂症和癫痫症。除了它们的功能意义之外，它们的突触的刻板印象 组织使 ChC 成为研究 IN 突触特异性分子机制的有吸引力的模型。 我们的初步数据表明： (1) 表达已知相互结合的 IgSF11 蛋白 在 ChC 和层特异性目标 PN 中，(2) 已知可与富含 AIS 的蛋白质结合的 Gldn 蛋白质， NF186，优先在 ChC 中表达，(3) ChC 中的 IgSF11 在其突触前发挥重要作用 (4) Gldn 和 NF186 似乎在启动 ChC 突触中发挥作用，(5) 游离的 IgSF11 Gldn-NF186 系统似乎不会诱导 ChC 突触。根据我们的发现，我们建议测试 层特异性突触发生作用和亚细胞域特异性识别的假设 分别通过 IgSF11 同嗜性相互作用和 Gldn-NF186 相互作用介导 确定 ChC 突触特异性。我们将追求以下具体目标来检验我们的假设。在目标 1 中， 我们将确定突触前和突触后神经元之间 IgSF11 同亲相互作用的作用 ChC 形成层特异性突触。在目标 2 中，我们将确定 Gldn 和 NF186 在 ChC 中的作用 AIS 上的突触形成。在目标 3 中，我们将确定 NF186/Gldn 在门控 IgSF11 中的调节作用 信号传导在 AIS 处诱导 ChC 突触前接触。完成本次学习，我们将收获的不仅是 对 IN 接线分子机制的重要见解，也是制定治疗策略的线索 功能性修复紊乱/受损的大脑。