Molecular Organization and Function of Paranodal Axo-glial Junctions

节旁轴胶质细胞连接的分子组织和功能

基本信息

批准号：
10439660
负责人：
MANZOOR A. BHAT
金额：
$ 38.75万
依托单位：
UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
依托单位国家：
美国
项目类别：
财政年份：
2001
资助国家：
美国
起止时间：
2001-05-01 至 2024-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10439660
关键词：
ANK3 gene Ablation Action Potentials Address Affect Alleles Amino Acids Anodes Appearance Architecture Area Arthrogryposis Axon CNTNAP1 gene Code Complex Congenital Neuropathy Contracture Cytoskeletal Proteins Defect Disease Electrophysiology (science)Future Genes Genetic Health Human In Vitro Invertebrates Joints Knowledge Lead Maintenance Membrane Modeling Molecular Motor Motor Neurons Mus Muscle Muscle Weakness Muscular Atrophy Mutant Strains Mice Mutation Myelin Nerve Neural Conduction Neuromuscular Junction Neurons Nodal Pathology Phenotype Physiological Play Point Mutation Potassium Channel Process Property Proteins Publishing Ranvier&apos s Nodes Role Scaffolding Protein Septate Sodium Spectrin Structure Tertiary Protein Structure Therapeutic Therapeutic Intervention Time TimeLine WHRN gene Work base betaIV spectrin contactin deafness design disability functional restoration gain of function genetic approach human model in vivo insight interest motor disorder mouse model mutant neurofascin neuromuscular neuropathology novel preservation prevent protein complex protein structure restoration voltage

项目摘要

Molecular Organization and Function of Paranodal Axo-glial Junctions Myelinated axons are organized into molecularly and functionally distinct domains defined by the presence of specific protein complexes that allow rapid saltatory action potential propagation. The paranodal domain contains the axo-glial junctions (AGJs) that are established by axonal Contactin-associated protein 1 (Cntnap1 or Caspr1), and Contactin (Cntn) and myelin/glial Neurofascin 155 (NF155). The nodal domains (nodes of Ranvier) are organized by neuronal Neurofascin 186 (NF186), voltage-gated sodium (Nav) channels, and two cytoskeletal scaffolding proteins Ankyrin G (AnkG) and βIV Spectrin (βIVSpec). In myelin-related diseases, this domain structure is compromised, leading to a decrease or loss of nerve conduction and muscle weakness. Our work demonstrated specific functions of the above proteins in the organization, maturation and maintenance of axonal domains. We used a novel genetic strategy for nodal domain reorganization in βIVSpec mutants, which allowed restoration of nodal function and prevented motor dysfunction. Importantly, recent identification of human CNTNAP1 mutations that are associated with severe AGJ and myelin defects further highlight the importance of AGJ proteins in nerve structure and function. We have generated new mouse models of three specific human CNTNAP1 mutations (Cys323Arg, Arg388Pro and Arg764Cys). These single amino acid changes in Cntnap1 affect its stability, transport and interactions with Cntn, and lead to disruption of the paranodal domains, and cause severe motor disability. While significant advances have been made regarding the organization of axonal domains; there still remain fundamental overarching questions related to AGJs and neuromuscular health: What impact do human mutations have on AGJ formation and physiological properties of axons? How does progressive disruption of axonal domains affect axons and the muscles they innervate? How does declining nerve activity change neuromuscular junctions (NMJs) and lead to muscle atrophy? In this revised application, we will use mouse models of human CNTNAP1 mutations and axonal domain disorganization and reorganization models to dissect the mechanisms that underlie the organization, maintenance and restoration of axonal domains. Our Specific Aims address three key gaps in knowledge: (1) What impact do human mutations in mouse Cntnap1 have on its structure/function, AGJ formation and axonal domain organization; and do these Cntnap1 mutations cause loss and/or gain of function phenotypes? (2) How does the timeline of axonal domain disorganization in NF186/AnkG mutants correlate with decline in nerve conduction leading to progressive motor disability? And (3) Does nodal domain reorganization and restoration of nerve conduction in bIV Spectrin mutants prevent/reverse muscle atrophy? Collectively, our studies will significantly advance our understanding of how human AGJ- and myelin-related pathologies impact axonal and neuromuscular health; and may offer critical insights into the timelines of functional restoration and potential avenues for future therapeutic interventions for these devastating neuropathologies.

偏射道轴 - 胶质连接的分子组织和功能髓鞘轴突被组织成分子和功能上不同的域，这些结构域的定义特定的蛋白质复合物，可以快速salony作用电势传播。偏an道路域包含由轴突接触蛋白相关蛋白1建立的轴向胶质连接（AGJ）（CNTNAP1或CASPR1），以及Contectin（CNTN）和髓磷脂/神经胶质神经素155（NF155）。节点域（Ranvier的节点）由神经元神经素186（NF186）组织，电压门控钠（NAV）通道，和两个细胞骨架脚手架蛋白Ankyrin G（ANKG）和βIV谱（βIVSPEC）。在与髓鞘有关的中疾病，这种域结构受到损害，导致神经传导和肌肉的降低或丧失弱点。我们的工作证明了上述蛋白质在组织中的特定功能，成熟和维护轴突域。我们使用了一种新型的遗传策略，用于βivspec中的淋巴结域重组突变体，可以恢复淋巴结功能并防止运动功能障碍。重要的是，最近与严重AGJ和髓磷脂缺陷相关的人类CNTNAP1突变的鉴定突出了AGJ蛋白在神经结构和功能中的重要性。我们已经生成了新鼠标三个特定人类CNTNAP1突变的模型（Cys323arg，arg388Pro和arg764Cys）。这些 CNTNAP1的氨基酸变化会影响其稳定性，运输和与CNTN的相互作用，并导致破坏偏阳结构域，并导致严重的运动障碍。尽管已经取得了重大进展关于轴突域的组织；仍然存在与 AGJ和神经肌肉健康：人类突变对AGJ形成和生理有什么影响轴突的特性？轴突域的渐进式破坏如何影响轴突和肌肉支配？神经活动下降如何改变神经肌肉连接（NMJ）并导致肌肉萎缩？在此修订后的应用中，我们将使用人CNTNAP1突变的鼠标模型和轴突领域混乱和重组模型，以剖析组织的基础的机制，轴突域的维护和恢复。我们的具体目的解决了知识的三个关键差距：（1）小鼠CNTNAP1中人类突变对其结构/功能，AGJ形成和轴突有什么影响领域组织；这些CNTNAP1突变是否会导致功能表型的损失和/或获得？（2）如何 NF186/ANKG突变体中的轴突结构域混乱的时间表是否与Neve的下降相关导致渐进运动残疾的传导？（3）进行淋巴结域的重组和恢复 BIV光谱突变体中神经传导预防/反向肌肉萎缩？总的来说，我们的学习将显着提高我们对人类AGJ和与髓磷脂相关的病理如何影响轴突和神经肌肉健康；并可能对功能恢复和潜力的时间表提供关键的见解这些毁灭性神经病理学的未来治疗干预措施的途径。