The role of acetylcholine signaling in the axonal wiring of cortical interneurons

乙酰胆碱信号在皮质中间神经元轴突布线中的作用

• 批准号: 10372840
• 负责人: HIROKI TANIGUCHI
• 金额: $ 23.63万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-01 至 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10372840
• 关键词: Acetylcholine; Action Potentials; Address; Adult; Attention deficit hyperactivity disorder; Axon; Brain; Brain Diseases; Brain Pathology; CRISPR/Cas technology; Calcium Channel; Cells; Cholinergic Receptors; Data; Defect; Development; Disease; Electroporation; Epilepsy; Equilibrium; Event; Exhibits; Filopodia; Gene Dosage; Gene Transfer; Generations; Genes; Germ Lines; Goals; Individual; Interneurons; Knockout Mice; Link; Mediating; Mental Depression; Modeling; Molecular; Morphogenesis; Morphology; Mus; Mutation; Neurons; Neurotransmitters; Nicotine; Phenotype; Production; Role; Schizophrenia; Series; Shapes; Signal Pathway; Signal Transduction; Signaling Molecule; System; T-Type Calcium Channels; Testing; Transplantation; Varicosity; Vertebral column; Viral Genes; basal forebrain; base; cholinergic; cholinergic neuron; cognitive function; experimental study; gain of function; gain of function mutation; genome editing; hippocampal pyramidal neuron; in vivo; loss of function; loss of function mutation; malformation; mouse genetics; mutant; novel; postnatal; prevent; relating to nervous system; stereotypy; transmission process

Project Summary/Abstract The cholinergic system, using acetylcholine (ACh) as a neurotransmitter, shapes plasticity and cognitive functions in the adult cortex by tuning cortical activity, and has been implicated in brain disorders such as epilepsy, attention-deficit hyperactivity disorder, depression, and schizophrenia. However, the role of ACh signaling in development of cortical circuits in normal and diseased conditions remains poorly understood. In particular, little is known about whether and how ACh signaling regulates the wiring of inhibitory interneurons (INs), cellular components critical for cortical computations. Cortical INs generally develop highly branched axons to establish local, dense circuit modules. Despite representing a crucial event during the wiring of IN circuits, the cellular and molecular mechanisms underlying IN axonal arborization remain elusive. The objective of our proposal is to establish the role of ACh signaling in shaping IN axonal arbors in vivo. We will also provide evidence that disease-relevant mutations in genes that are essential for ACh signaling could impact IN axonal branching, and that the axonal phenotype could be ameliorated by manipulating downstream components in ACh signaling. To achieve this goal, we will perform a series of experiments using the chandelier cell (ChC), which exclusively innervates axon initial segments of pyramidal neurons (PNs) and thus powerfully controls spike generation in PNs. Because of its stereotypy of the axonal organization, the ChC serves as an ideal model to study IN axonal morphogenesis. Our preliminary data has shown that (1) Axonal filopodia arising from varicosities serve as precursors of branches in vivo, (2) Filopodia initiation as well as the basal Ca2+ levels in ChC axonal varicosities are regulated by signaling from nicotinic AChRs (nAChRs) to T-type voltage dependent calcium channels (T- VDCCs), independently of action potentials/network activity, (3) CRISPR/Cas9-mediated T-VDCC loss-of- function (LOF) in single ChCs significantly reduces their axonal branching points, and (4) Systemic nicotine administration to developing postnatal mice increases ChC axonal arbors. Based on these results, we propose to test the hypothesis that the nAChR-T-VDCC signaling pathway shapes ChC axonal arborization, and disease- relevant mutations in ACh signaling molecules cause wiring defects in ChCs. In Aim 1, we will elucidate the role of the nAChR-T-VDCC signaling pathway in ChC axonal arborization in vivo. In Aim 2, we will determine the effect of the epilepsy-related gain-of-function (GOF) mutation in nAChRs on ChC axonal arborization, and elucidate whether manipulating T-VDCCs can be a way to revert the nAChR GOF phenotype. Our study will provide first evidence for the developmental role of ACh signaling in the wiring of INs in the normal and diseased cortices as well as a novel hint for developing strategies to prevent and ameliorate brain disorders associated with ACh signaling.

项目摘要/摘要 胆碱能系统利用乙酰胆碱(ACh)作为神经递质，塑造可塑性和认知能力 通过调节皮质活动在成人皮质中发挥作用，并与癫痫等脑部疾病有关， 注意力缺陷多动障碍、抑郁症和精神分裂症。然而，ACh信号在其中的作用 正常和疾病条件下皮质环路的发育仍然知之甚少。尤其是，几乎没有 已知ACh信号是否以及如何调节抑制性中间神经元(INS)的连接 对大脑皮层计算至关重要的组件。皮质INS通常发育成高度分支的轴突，以建立 本地密集电路模块。尽管代表着IN电路布线过程中的一个关键事件，但蜂窝和 轴突树枝形成的分子机制仍然难以捉摸。 我们建议的目标是确定ACh信号在轴突形成中的作用 在活体内。我们还将提供证据，证明与疾病相关的基因突变对ACh至关重要 信号可以影响轴突分支，轴突表型可以通过 操纵ACH信令中的下游组件。为了实现这一目标，我们将实施一系列 使用枝形吊灯细胞(CHC)的实验，该细胞专门支配锥体轴突的起始段 神经元(PNS)，从而有力地控制PNS中的棘波产生。 由于其对轴突组织的刻板印象，CHC是研究轴突的理想模型 形态发生。我们的初步数据表明：(1)静脉曲张引起的轴索足可作为 活体分支的前体；(2)CHC轴索静脉曲张的丝状足起始和基础钙水平 受烟碱型AChRs(NAChRs)到T型电压依赖性钙通道(T- VDCC)，与动作电位/网络活动无关，(3)CRISPR/Cas9介导的T-VDCC丢失。 单个CHC的功能(LOF)显著减少其轴突分支点，以及(4)全身尼古丁 给发育中的小鼠用药可增加CHC轴突粗壮。基于这些结果，我们提出了 为了验证nAChR-T-VDCC信号通路形成CHC轴突树枝的假设，以及疾病- ACh信号分子中的相关突变会导致CHC的线路缺陷。在目标1中，我们将阐明 研究nAChR-T-VDCC信号通路在CHC轴突分支中的作用。在目标2中，我们将确定 NAChRs癫痫相关功能增强(GOF)突变对CHC轴突分支的影响 阐明操纵T-VDCC是否可以逆转nAChR GOF表型。 我们的研究将为ACh信号在INS连接中的发育作用提供第一个证据。 正常和病变的大脑皮层以及开发预防和改善大脑的策略的新提示 与ACh信号相关的疾病。