Early mechanisms mediating the organization of the axon initial segment impact the formation of axo-axonic synapses

介导轴突初始段组织的早期机制影响轴突突触的形成

基本信息

批准号：
10291333
负责人：
Rochelle Marie Hines
金额：
$ 43.1万
依托单位：
UNIVERSITY OF NEVADA LAS VEGAS
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-07-15 至 2024-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10291333
关键词：
ANK3 gene Adult Anions Award Axon Brain Cations Cells Childhood Neurological Disorder Collaborations Complement Complex Data Development Disease Engineering Environment Functional disorder Future Genes Goals Grant Health Histologic Histology Human Immunohistochemistry Impairment Inhibitory Synapse Institution Knowledge Light Manuscripts Maps Medial Mediating Medical Mental Health Mentors Methods Microscopy Molecular Morphology Mus Mutation Neurodevelopmental Disorder Neurons Opsin Outcome Pathologic Pattern Play Principal Investigator Probability Process Production Proteins Publishing Peer Reviews Research Research Project Grants Resolution Resources Role STEM career Schools Seizures Self Efficacy Signal Transduction Site Students Symptoms Synapses Technical Expertise Techniques Time Training Tweens Western Blotting Work base betaIV spectrin cell type collybistin experimental study frontal lobe graduate student insight mouse model neural circuit neural patterning neurodevelopment neurofascin neurotransmission novel postnatal development protein aggregation receptor relating to nervous system skills stem success synaptogenesis training opportunity undergraduate research undergraduate student

项目摘要

PROJECT SUMMARY Brain development is a complex process that requires the production and differentiation of numerous cells and cell types, with the additional challenge of spatial and temporal precision in the neural circuitry that connects these cells. Improper formation of neural circuitry leads to impaired control over brain activity patterns and is broadly thought to contribute to a number of childhood neurological disorders. Multiple lines of research suggest that inhibitory GABAergic circuitry in particular contributes to the pathophysiology of neurodevelopmental disor- ders, yet these disorders remain poorly treated. This project is focused on the GABAergic synapse formed be- tween a chandelier cell and a specialized neuronal compartment called the axon initial segment (AIS), forming an axo-axonic synapse. Chandelier cells exert powerful control over neural activity patterns exerting shunting inhibition at the AIS of large groups of principal cells, which impacts their probability of generating an electrical signal. Axo-axonic synapses are characterized by GABAA receptors containing the α2 subunit and collybistin, a specific interacting partner we have recently identified. We have developed and characterized a mouse model with a substitution mutation in the GABAA receptor α2 subunit (Gabra2-1) that diminishes interaction with colly- bistin, causing reduced numbers of axo-axonic synapses and spontaneous seizures during development. On this premise, we hypothesize that the α2 subunit contributes to the organization of the AIS in order to facilitate the formation of axo-axonic synapses. In this proposal we will examine axo-axonic synapse development and AIS organization using immunohistochemistry and expansion microscopy, as well as circuit dysfunction using cortical field recordings. We will examine how these changes correlate with symptom onset in the Gabra2-1 mouse and also evaluate novel methods to replace lost control by using a novel light activated cation channel targeted to the AIS. Relevance to human health: The proposed project is expected to yield detailed information about how the AIS organizes during development, as well as the formation of axo-axonic synapses in both typical and pathological conditions, providing both basic knowledge about brain development and translational insights for neurodevelopmental disorders. This proposal also offers a novel means of actively manipulating the AIS, a site known for its potential to control cortical activity patterns. Outcomes: This work will be conducted entirely by undergraduate and graduate students at UNLV, which is one of the nation’s most diverse campuses. Thus, this project will provide instrumental training opportunities for the diversification of the biomedical workforce, as well as enhance the research environment of our institution.

项目概要大脑发育是一个复杂的过程，需要大量细胞的产生和分化细胞类型，以及连接神经回路的空间和时间精度的额外挑战这些细胞的神经回路形成不当会导致对大脑活动模式的控制受损。多项研究表明，广泛认为会导致许多儿童神经系统疾病。抑制性 GABA 能回路尤其有助于神经发育障碍的病理生理学然而，这些疾病的治疗效果仍然不佳。该项目的重点是形成的 GABA 突触。枝形细胞和称为轴突初始段（AIS）的特殊神经室之间，形成轴突突触对神经活动模式施加强大的控制，从而产生分流。对大群主细胞的 AIS 进行抑制，这会影响它们产生电的概率轴突突触的特征是含有 α2 亚基和 Collybistin（一种）的 GABAA 受体。我们最近确定了特定的相互作用伙伴，我们开发并表征了小鼠模型。 GABAA 受体 α2 亚基 (Gabra2-1) 发生取代突变，减少与 colly- 的相互作用 bistin，导致发育过程中轴突突触数量减少和自发性癫痫发作。在此前提下，我们认为α2亚基有助于AIS的组织，以促进轴突突触的形成在本提案中，我们将研究轴突突触的发育和使用免疫组织化学和扩展显微镜观察 AIS 组织，以及使用我们将研究这些变化与 Gabra2-1 中症状发作的关系。小鼠并评估通过使用新型光激活阳离子通道来替代失去控制的新方法针对 AIS 与人类健康的相关性：拟议项目预计将产生详细信息。关于 AIS 在发育过程中如何组织，以及两种典型的轴突突触的形成和病理状况，提供有关大脑发育的基本知识和转化见解该提案还提供了一种主动操纵 AIS 的新方法，即一种以其控制皮质活动模式的潜力而闻名。结果：这项工作将完全进行。由内华达大学拉斯维加斯分校的本科生和研究生组成，该校是全国最多元化的校园之一。该项目将为生物医学劳动力的多样化提供有益的培训机会，因为并改善我们机构的研究环境。