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: 10011907
• 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 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10011907
• 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; Neuronal Injury; 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; conditional knockout; disability; disabling symptom; effective therapy; in vivo; 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.

项目摘要/摘要 Schwann细胞和神经元对于形成髓神经纤维至关重要 周围神经系统（PNS）。除了通过髓鞘鞘的轴突电绝缘，Schwann 细胞组装Ranvier的节点，Ranvier是快速有效的动作电位所需的令人兴奋的轴突域 传播。此外，雪旺细胞积极调节PNS变性和再生。但是， 这些结构如何形成，维持和破坏疾病的细胞和分子机制 条件仍然很少理解。在知识方面，这种关键差距限制了该领域操纵该领域的能力 用于治疗PNS疾病和损伤的Schwann细胞和神经元。该应用程序的总体目标 是在PNS髓神经形成和损伤过程中确定关键的分子机制。这 此处提供的先前的研究和初步数据已经确定了钙依赖性钙的激活 这些过程中涉及细胞内半胱氨酸蛋白酶和Calpain-2水平的升高。 在形成髓磷脂之前，小鼠Calpain-2的组成型敲除导致胚胎致死性，进一步 强调Calpain-2在包括神经系统在内的多个器官发展中的重要性。 中心假设是Calpain-2调节外周髓神经的形成和损伤。开始 检验此假设，该应用将产生有条件的敲除小鼠，缺乏Calpain-2 Schwann细胞（AIM 1）或感觉神经元（AIM 2）。特定目标将检验Schwann的假设 细胞Calpain-2介导PNS髓鞘形成。具体目标两个将检验轴突钙蛋白酶-2的假设 调节Ranvier结构的PNS节点。 PNS中的髓磷脂和淋巴结结构，沿PNS的神经传导 骨髓轴突和动物行为将在产后发育和成人条件下检查 敲除和控制小鼠。该应用在概念上是创新的，因为我们建议Calpain-2是一个 PNS中髓神经形成的关键调节剂。该应用程序将产生新颖的Calpain-2条件 敲除小鼠，将在以后的研究中用于确定雪旺细胞特异性或神经元特异性角色 PNS损伤和修复中的Calpain-2。拟议的研究很重要，因为目标的完成将 识别calpain-2作为髓鞘神经形成和PNS中重塑的潜在调节剂。 此外，未来的研究，利用本应用程序中产生的条件敲除小鼠，预计将 发现Calpain-2在PNS损伤中的细胞类型特异性角色，并将大大影响未来的翻译 旨在开发各种PNS疾病和损伤的新疗法的研究。