Cell type-specific roles of calpain-2 in formation of peripheral myelinated nerves

calpain-2 在周围有髓神经形成中的细胞类型特异性作用

• 批准号: 9805892
• 负责人: Keiichiro Susuki
• 金额: $ 7.5万
• 依托单位: WRIGHT STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-15 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9805892
• 关键词: 1 year old; AVIL gene; Action Potentials; Adult; Afferent Neurons; Age; Alleles; Animal Behavior; Axon; Behavior; Biological Assay; Biology; Calcium; Calpain; Caspase; Cytoskeleton; Data; Demyelinating Diseases; Development; Disease; Electron Microscopy; Embryo; Erinaceidae; Family; Functional disorder; Future; Gene Expression; Gene Proteins; Growth; Immune; Immunofluorescence Microscopy; Injury; Knock-out; Knockout Mice; Knowledge; Length; Limb structure; LoxP-flanked allele; Maintenance; Mediating; Messenger RNA; Molecular; Multiple Sclerosis; Mus; Mutant Strains Mice; Myelin; Myelin Sheath; Myelinated nerve fiber; Natural regeneration; Nerve; Nerve Fibers; Nerve compression syndrome; Nervous System Trauma; Nervous system structure; Neural Conduction; Neuraxis; Neurons; Nodal; Organ; Patients; Peripheral; Peripheral Nerves; Peripheral Nervous System; Peripheral Nervous System Diseases; Process; Public Health; Publishing; Ranvier' s Nodes; Reporting; Research; Role; Rotarod Performance Test; Schwann Cells; Structure; Testing; Translational Research; Western Blotting; axonal degeneration; base; cell type; disability; disabling symptom; effective therapy; in vivo; injured; injury and repair; innovation; m-calpain; mouse model; mu-calpain; mutant; myelination; nerve conduction study; nervous system development; novel; novel therapeutics; postnatal; postnatal development; sciatic nerve; spinal nerve posterior root; tool; translational impact

Project summary/abstract Both Schwann cells and neurons are essential for the formation of myelinated nerve fibers in the peripheral nervous system (PNS). In addition to the electrical insulation of axons by myelin sheaths, Schwann cells assemble nodes of Ranvier, the excitable axonal domains required for rapid and efficient action potential propagation. Furthermore, Schwann cells actively modulate PNS degeneration and regeneration. However, the cellular and molecular mechanisms of how these structures are formed, maintained, and disrupted in disease conditions remain poorly understood. This critical gap in knowledge limits the field’s ability to manipulate the Schwann cells and neurons for treatment of PNS diseases and injuries. The overall objective of this application is to identify a critical molecular mechanism in the process of PNS myelinated nerve formation and injury. The prior studies and preliminary data provided here have identified activation of calpains, calcium-dependent intracellular cysteine proteases, and elevation of calpain-2 levels are involved in these processes. The constitutive knockout of calpain-2 in mice results in embryonic lethality before myelin is formed, further emphasizing the importance of calpain-2 in development of multiple organs including nervous system. The central hypothesis is that calpain-2 modulates formation and injury of peripheral myelinated nerves. To begin to test this hypothesis, this application will generate conditional knockout mice lacking calpain-2 in myelinating Schwann cells (Aim 1) or in sensory neurons (Aim 2). Specific aim one will test the hypothesis that Schwann cell calpain-2 mediates PNS myelination. Specific aim two will test the hypothesis that axonal calpain-2 modulates PNS node of Ranvier structures. Myelin and nodal structures in PNS, nerve conduction along PNS myelinated axons, and animal behavior will be examined during postnatal development and in adult conditional knockout and control mice. This application is conceptually innovative, in that we propose that calpain-2 is a key modulator of myelinated nerve formation in PNS. This application will generate novel calpain-2 conditional knockout mice, which will be used in future studies to determine Schwann cell-specific or neuron-specific roles of calpain-2 in PNS injury and repair. The proposed research is significant, because completion of the aims will identify calpain-2 as a potential modulator of myelinated nerve formation and remodeling in the PNS. Furthermore, future research, utilizing conditional knockout mice generated in this application, is expected to uncover cell type-specific roles of calpain-2 in PNS injuries and will substantially impact future translational research aimed at the development of novel therapies for a wide variety of PNS diseases and injuries.

项目概要/摘要 雪旺氏细胞和神经元都是形成有髓神经纤维所必需的。 外周神经系统（PNS）。除了髓鞘对轴突的电绝缘外， 细胞组装Ranvier节点，快速和有效的动作电位所需的可兴奋轴突域 传播此外，雪旺细胞积极调节PNS的变性和再生。但 这些结构如何在疾病中形成、维持和破坏的细胞和分子机制 人们对情况仍然知之甚少。知识上的这一关键差距限制了该领域操纵 用于治疗PNS疾病和损伤的雪旺细胞和神经元。本申请的总体目标 目的是明确PNS有髓神经形成和损伤过程中的关键分子机制。的 先前的研究和这里提供的初步数据已经确定了钙蛋白酶的激活， 细胞内半胱氨酸蛋白酶和钙蛋白酶-2水平的升高参与这些过程。的 小鼠中钙蛋白酶-2的组成型敲除导致髓鞘形成之前的胚胎死亡， 强调钙蛋白酶-2在包括神经系统在内的多器官发育中的重要性。的 中心假设是钙蛋白酶-2调节外周有髓神经的形成和损伤。开始 为了验证这一假设，该应用将产生在髓鞘形成中缺乏钙蛋白酶-2的条件性敲除小鼠， 雪旺细胞（Aim 1）或感觉神经元（Aim 2）。具体目标之一是检验许旺 细胞钙蛋白酶-2介导PNS髓鞘形成。具体目标二将检验轴突钙蛋白酶-2 调节Ranvier结构的PNS结。PNS中的髓鞘和结节结构，沿PNS的神经传导沿着 有髓轴突和动物行为将在出生后发育和成年条件下进行检查。 敲除小鼠和对照小鼠。该应用在概念上是创新的，因为我们提出钙蛋白酶-2是一种 PNS中有髓神经形成的关键调节物。该应用将产生新的钙蛋白酶-2条件 敲除小鼠，这将用于未来的研究，以确定雪旺细胞特异性或神经元特异性的作用 钙蛋白酶-2在PNS损伤和修复中的作用。这项研究具有重要的意义，因为目标的完成将 鉴定钙蛋白酶-2作为PNS中有髓神经形成和重塑的潜在调节剂。 此外，未来的研究，利用条件敲除小鼠在此应用中产生的，预计将 揭示钙蛋白酶-2在PNS损伤中的细胞类型特异性作用，并将对未来的翻译产生重大影响。 研究旨在为各种PNS疾病和损伤开发新的治疗方法。