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（逐字研究申请人的摘要）：髓神经纤维 对于通过盐酸传导有效地传播冲动至关重要。 髓鞘在解剖和生理上组织成纵向段 （节间）被Ranvier节点中断。高浓度 电压门控钠通道位于节点中，具体 钾通道主要局限于偏峰区域。节点 对于沿神经的盐酸传导至关重要，但是分子 确定淋巴结形成的信号知之甚少。最近的研究 证明了Ig中细胞粘附分子（CAM）的子集 超家族（即NR-CAM和Neurofascin）专门定位于 在其形成的早期阶段节点。 我们最近证明了NR-CAM的重组形式可以扰动 使用涉及背根神经节（DRG）的共培养系统的节点形成 神经元和雪旺细胞。结果强烈表明NR-CAM和 它的配体在节点形成中。因此，我们建议探索功能 可以与之相互作用的NR-CAM和蛋白质的 RPTPBETA，Neurofascin和Ankyrin在节点的形成和维护中 Ranvier。 我们的第一个目标是确定NR-CAM和 已知可以在不同的神经元和schwann细胞中与之相互作用的蛋白质 神经分化的阶段。我们还将使用最近有的老鼠 生成的NR-CAM蛋白搜索潜力的无效 节点和神经的结构和发展的改变 传导。我们的第二个目标是分析NR-CAM和蛋白质的作用 可以使用Schwann细胞神经元共培养在节点形成中与之相互作用 系统。 CAM的重组形式为FC融合蛋白和特定抗体 针对NR-CAM及其约束伙伴将用于测试其能力 共培养系统中的扰动淋巴结形成。节点形成将是 通过用抗体和针对Ankyrin和钠通道的抗体染色来分析 通常在文化中的节点聚集。我们的第三个目标是 确定与节点相关的NR-CAM受体中的特定结合区域 形成并分析了信号蛋白聚类的分子机制 节点。 拟议的研究将阐明NR-CAM及其结合的功能 PNS节点开发的合作伙伴，也可能提供新的见解 中枢神经系统中神经发展的分子基础。将来，这样 信息可能会导致新的治疗策略，以防止伤害和 恢复髓神经的功能，并在 多发性硬化症。