Examining neuronal resilience in a mouse model of sporadic ALS

检查散发性 ALS 小鼠模型的神经元弹性

• 批准号: 10381720
• 负责人: VIRGINIA M LEE
• 金额: $ 35.22万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10381720
• 关键词: Acute; Amyotrophic Lateral Sclerosis; Area; Attenuated; Autopsy; Axon; Brain; Cells; Code; Complement; Complementary DNA; Denervation; Development; Disease; Disease Progression; Electrophysiology (science); Fiber; Financial compensation; Gene Targeting; Genes; Grouping; Health; Human; Image; Immune; Impairment; Individual; Injury; Intramuscular; Lasers; Measures; Mediating; Microglia; Modeling; Molecular; Molecular Profiling; Motor; Motor Endplate; Motor Neurons; Movement; Mus; Muscle; Nerve; Nerve Crush; Neurodegenerative Disorders; Neuroglia; Neuromuscular Junction; Neurons; Onset of illness; Paralysed; Pathogenesis; Pathologic; Pathway interactions; Patients; Pattern; Pharmacology; Physiology; Population; Preparation; Process; Proteins; RNA; Recovery; Resistance; Sampling; Series; Silver; Spinal Cord; Synapses; Techniques; Time; TimeLine; Tissues; Tracer; Transgenes; adeno-associated viral vector; base; coping mechanism; design; esterase; experimental study; gait examination; insight; kinematics; knock-down; motor behavior; mouse model; muscle physiology; muscle reinnervation; nerve damage; nerve supply; neuron loss; overexpression; prevent; protein TDP-43; reinnervation; resilience; response; restoration; sciatic nerve; sporadic amyotrophic lateral sclerosis; therapeutic target; therapy development; tibialis anterior muscle; transcriptome; transcriptome sequencing; transcriptomics; transgene expression

Project Summary/Abstract Following an injury to the brain, healthy neurons that are adjacent to the damaged area can sometimes take over the functions performed by the impaired neurons. This process has been best studied after acute nerve damage, but there is evidence that compensation by surviving neurons is also happening in the early stages of neurodegenerative diseases. In amyotrophic lateral sclerosis (ALS), the fiber type grouping in muscle samples taken from patients suggests that after an initial loss of connections between motor neurons (MNs) and muscles, new nerves are able to reconnect to allow patients to maintain movement during the disease process. A second observation made at the time of autopsy is that the vast majority of patients have an accumulation of a mislocalized protein called TDP-43 in the surviving MNs. However, because these cells are inaccessible in early disease stages, the molecular mechanisms for coping with disease processes in the MNs that send out new connections to muscles are unknown. In order to determine the dynamic responses that could allow a subpopulation of MNs to cope specifically with mislocalized TDP-43 and send out new axonal connections to muscles to prevent paralysis, we developed a mouse model in which we can induce neuronal expression of mislocalized human TDP-43, called rNLS8 mice. We then showed that rNLS8 mice have certain subsets of MNs that are uniquely vulnerable to disease, and that surviving MNs can effectively take the place of these cells, even late into the disease course. In this study, we will now identify the populations of MNs responsible for the reinnervation and restoration of function of vulnerable muscles after the initial TDP-43 triggered MN loss (Aim 1), using a combination of neuronal tracing techniques, muscle physiology, and imaging at the neuromuscular junction. We will then look for the upstream contribution of the brain's immune cells, microglia, to MN plasticity and the resultant circuit changes (Aim 2) by pharmacologically eliminating microglia and selectively reintroducing microglial derived factors that have been previously shown to influence neuronal function. Finally, molecular differences between MNs that innervate the same muscle before and after TDP-43 triggered axonal dieback will be uncovered by RNA- Sequencing and the top gene targets will be validated for their effect on motor function during ALS-like disease in rNLS8 mice (Aim 3). Completion of these studies should provide valuable insights into the potential mechanisms by which subsets of MNs can tolerate a build-up of cytoplasmic TDP-43. Moreover, understanding the mechanisms of neuronal compensation could allow for the development of therapies aimed at supporting surviving cells in order to extend their natural plasticity to slow disease and maintain function in patients.

项目摘要/摘要 在大脑受伤后，与受损区域相邻的健康神经元有时会受到 在受损神经元执行的功能上。急性神经后最好对此过程进行研究 损坏，但有证据表明，幸存神经元的赔偿也正在发生 神经退行性疾病。在肌萎缩性侧索硬化症（ALS）中，肌肉样品中的纤维类型组 从患者中取出的表明，运动神经元（MN）和肌肉之间的最初连接丧失后， 新神经能够重新连接，使患者在疾病过程中保持运动。第二 尸检时进行的观察是，绝大多数患者的积累 存活的MN中称为TDP-43的错误定位蛋白。但是，由于这些细胞在早期无法访问 疾病阶段，用于应对MN中疾病过程的分子机制发送了新的 与肌肉的联系是未知的。为了确定可以允许的动态响应 MNS的亚群专门针对错误定位的TDP-43，并将新的轴突连接发送到 肌肉预防瘫痪，我们开发了一种小鼠模型，我们可以诱导神经元表达 错误定位的人类TDP-43，称为RNLS8小鼠。然后，我们表明RNLS8小鼠具有某些MN的子集 独特容易受到疾病的攻击，幸存的MN可以有效地代替这些细胞，甚至 进入疾病的后期。 在这项研究中，我们现在将确定负责加重和恢复的MN的种群 最初的TDP-43触发MN损失后脆弱肌肉的功能（AIM 1），使用神经元组合 在神经肌肉连接处进行追踪技术，肌肉生理和成像。然后，我们将寻找 大脑的免疫细胞，小胶质细胞对MN可塑性的上游贡献，并且最终的电路变化 （AIM 2）通过药理学消除小胶质细胞并有选择地重新引入小胶质细胞衍生因子 以前已显示出影响神经元功能。最后，MN之间的分子差异 在TDP-43触发轴突死亡之前和之后，将相同的肌肉支配将被RNA-发现 测序和最高基因靶标将在ALS样疾病期间对运动功能的影响进行验证 在RNLS8小鼠中（AIM 3）。这些研究的完成应提供对潜力的宝贵见解 MN子集可以耐受细胞质TDP-43的堆积的机制。而且，理解 神经元补偿的机制可以允许开发旨在支持的疗法 存活的细胞以扩展其自然可塑性以减慢疾病并维持患者的功能。