NR/CAM AND FORMATION OF NODE OF RANVIER

NR/CAM 和 RANVIER 节点的形成

• 批准号: 6394178
• 负责人: MARTIN H GRUMET
• 金额: $ 23.46万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-03 至 2003-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6394178
• 关键词: Schwann cells; ankyrins; biological signal transduction; gene expression; genetically modified animals; immunocytochemistry; laboratory mouse; mixed tissue /cell culture; myelination; neural cell adhesion molecules; neurogenesis; neurogenetics; node of Ranvier; protein isoforms; sodium channel

DESCRIPTION (Verbatim from the Applicant's Abstract): Myelinated nerve fibers are critical for efficient propagation of impulses via saltatory conduction. Myelin is organized anatomically and physiologically into longitudinal segments (internodes) that are interrupted by the nodes of Ranvier. High concentrations of voltage-gated sodium channels are located in the node, and specific potassium channels are restricted primarily to the paranodal regions. The nodes are critical for saltatory conduction along the nerve, but the molecular signals that determine node formation are poorly understood. Recent studies demonstrated that a subset of cell adhesion molecules (CAMs) in the Ig Superfamily (i.e., Nr-CAM and neurofascin) are specifically localized to the node at early stages of its formation. We have recently demonstrated that a recombinant form of Nr-CAM can perturb node formation using a co-culture system involving dorsal root ganglion (DRG) neurons and Schwann cells. The results strongly indicate a role for Nr-CAM and its ligands in node formation. Therefore, we propose to explore the functions of Nr-CAM and proteins that can interact with it, i.e., TAG-1, contactin, RPTPbeta, neurofascin and ankyrin, in the formation and maintenance of the node of Ranvier. Our first goal is to determine the patterns of expression of Nr-CAM and proteins known to interact with it in neurons and Schwann cells at different stages of nerve differentiation. We will also use mice that we have recently generated that are null for the Nr-CAM protein to search for potential alterations in the structure and development of the node and in nerve conduction. Our second goal is to analyze the role of Nr-CAM and proteins that can interact with it in node formation using a Schwann cell-neuron co-culture system. Recombinant forms of CAMs as Fc fusion proteins and specific antibodies against Nr-CAM and its binding partners will be used to test their ability to perturb node formation in the co-culture system. Node formation will be analyzed by staining with antibodies against ankyrin and sodium channels that normally become clustered at the nodes in culture. Our third goal is to identify specific binding regions in the Nr-CAM receptors involved in node formation and to analyze molecular mechanisms that signal protein clustering at nodes. The proposed studies will clarify the functions of Nr-CAM and its binding partners in node development in the PNS and may also provide new insights into the molecular basis of nerve development in the CNS. In the future, such information may lead to new therapeutic strategies to prevent injury and restore function in myelinated nerves that become damaged and remyelinated in multiple sclerosis.

描述（来自申请人摘要的逐字）：有髓神经纤维 是通过跳跃传导有效传播脉冲的关键。 髓鞘在解剖学和生理学上组织成纵向节段 （节间）被兰维尔的节点中断。高浓度 的电压门控钠通道位于节点，和特定的 钾通道主要局限于结旁区。节点 对于沿着神经的跳跃式传导是至关重要的，但是分子 决定节点形成的信号知之甚少。最近的研究 证明了IG中的细胞粘附分子（CAM）亚群 超家族（即，Nr-CAM和神经成束蛋白）特异性定位于 节点在其形成的早期阶段。 我们最近已经证明，重组形式的Nr-CAM可以干扰 使用涉及背根神经节（DRG）的共培养系统的结形成 神经元和雪旺细胞。结果强烈表明Nr-CAM和 它的配体参与了节点的形成。因此，我们建议探讨 Nr-CAM和可以与之相互作用的蛋白质，即，TAG-1，接触素， RPTP β、神经成束蛋白和锚蛋白在淋巴结形成和维持中的作用 关于Ranvier 我们的第一个目标是确定Nr-CAM的表达模式， 已知在不同温度下，神经元和许旺细胞中与之相互作用的蛋白质 神经分化的阶段。我们还将使用最近 生成的Nr-CAM蛋白无效，以搜索潜在的 在结构和发展的节点和神经的变化 传导我们的第二个目标是分析Nr-CAM和蛋白质的作用， 可以在雪旺细胞-神经元共培养的节点形成中与之相互作用 系统作为Fc融合蛋白和特异性抗体的CAM的重组形式 针对Nr-CAM及其结合伴侣的抗体将用于测试它们的能力， 干扰共培养系统中的结形成。节点形成将是 通过用抗锚蛋白和钠通道的抗体染色来分析， 在培养过程中通常会聚集在节点上。我们的第三个目标是 确定参与节点的Nr-CAM受体中的特异性结合区域 形成并分析信号蛋白质聚集的分子机制 结 这些研究将阐明Nr-CAM的功能及其与肿瘤细胞的结合， 在PNS节点开发的合作伙伴，也可能提供新的见解， 中枢神经系统神经发育的分子基础。未来这类 信息可能会导致新的治疗策略，以防止损伤， 恢复受损和再生髓鞘的有髓鞘神经的功能， 多发性硬化