Maintenance and Reorganization of Molecular Domains in Myelinated Axons

有髓轴突分子域的维护和重组

• 批准号: 8910170
• 负责人: ANNA M TAYLOR
• 金额: $ 5.24万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-02-01 至 2018-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8910170
• 关键词: Ablation; Action Potentials; Address; Adult; Affect; Alternative Splicing; Antibodies; Axon; Behavioral; Binding; Biochemical; Cell Adhesion Molecules; Cell surface; Cells; Data; Demyelinating Diseases; Demyelinations; Deterioration; Development; Disease; Event; Future; Gated Ion Channel; Genes; Genetic; Health; Individual; Inflammatory; Lead; Maintenance; Mammals; Molecular; Movement; Multiple Sclerosis; Mus; Muscle; Muscle function; Myelin; Neural Conduction; Neuroglia; Neurons; Patients; Phenotype; Protein Isoforms; Ranvier' s Nodes; Reporting; Research Personnel; Role; Sodium Channel; Techniques; Therapeutic; Time; TimeLine; Transgenic Mice; axonal degeneration; base; design; disability; improved; innovation; insight; molecular domain; mouse model; myelination; neurofascin; neurotransmission; nodal protein; novel; prevent; public health relevance; repaired; restoration; voltage; young adult

 DESCRIPTION (provided by applicant): Intricate molecular interactions between neurons and supporting glia cells are essential for the rapid propagation of action potentials and form the basis for myelinated axons to achieve saltatory conduction. Previously, the cell surface adhesion molecule Neurofascin (Nfasc) has been shown to have a dual-role, essential to the establishment of axonal domains from both the glial and neuronal interface. While the neuron-specific isoform (NF186) is indispensable for clustering of voltage-gated sodium channels at nodes of Ranvier; the glial-specific isoform (NF155) is required for myelinating glial cells to organize the paranode. Although many studies have used mouse models during development to address the roles of NF155 and NF186 in assembling paranodes and nodes, respectively; researchers have only begun to elucidate their roles in the maintenance and long-term health of the myelinated axons. Furthermore, no studies have addressed their potential to reestablish disrupted molecular domains in adults. In this proposal, we seek to define the role of NF155 and NF186 in the maintenance and repair of molecular domains in myelinated axons. We hypothesize that loss of Nfasc from adults leads to a sequential disruption of molecular domains that is reversible during a critical time frame. The proposed studies utilize novel spatio-temporally controlled transgenic mouse models to genetically ablate Nfasc in adult mice and then to re-express Nfasc at various time points. These mice will be evaluated through a combination of immunohistochemical, biochemical, ultrastructual, electrophysiological, and behavioral techniques in the following specific aims: Aim 1: To ascertain the long-term consequences of disrupted paranodal axo-glial junctions and the potential to restore the paranodal domain in myelinated axons. Aim 2: To elucidate the sequence in which the molecular components at nodes of Ranvier disorganize and potentially reorganize in myelinated axons. This innovative approach will lead to a better understanding of the critical time frame in which axo-glial interactions can be repaired and could ultimately aid in the design of future therapies to restore demyelinated axons and increase mobility in demyelinating diseases, such as multiple sclerosis.

 描述(申请人提供)：神经元和支持神经胶质细胞之间复杂的分子相互作用对于动作电位的快速传播是必不可少的，并形成有髓轴突实现跳跃性传导的基础。以前，细胞表面黏附分子神经束蛋白(NFasc)被证明具有双重作用，对于从神经胶质和神经元界面建立轴突结构域是必不可少的。神经元特异性异构体(NF186)对于兰维尔结节上电压门控钠通道的聚集是必不可少的，而神经胶质特异性异构体(NF155)是形成髓鞘的神经胶质细胞组织旁阳极所必需的。尽管许多研究在发育过程中使用了小鼠模型来分别研究NF155和NF186在组装副神经节和结节中的作用，但研究人员才开始阐明它们在有髓轴突的维持和长期健康中的作用。此外，还没有研究表明它们有可能在成人体内重建被破坏的分子结构域。在这个提案中，我们试图确定NF155和NF186在有髓轴突分子结构域的维持和修复中的作用。我们假设，从成年人身上失去NFasc会导致分子结构域的顺序破坏，这在关键的时间框架内是可逆的。本研究利用新的时空控制转基因小鼠模型，在成年小鼠体内进行基因消融，然后在不同的时间点重新表达NFasc。这些小鼠将通过结合免疫组织化学、生化、超微结构、电生理和行为学技术进行评估，具体目的如下：目的1：确定结旁轴突连接中断的长期后果以及修复有髓轴突的结旁区域的可能性。目的2：阐明有髓轴突Ranvier节点处分子成分解体和重组的顺序。这种创新的方法将导致更好地理解轴突-神经胶质相互作用可以修复的关键时间框架，并最终可能有助于设计未来的治疗方案，以恢复脱髓鞘的轴突，并增加多发性硬化症等脱髓鞘疾病的流动性。