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: 10610826
• 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 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10610826
• 关键词: Acute; Amyotrophic Lateral Sclerosis; Area; Attenuated; Autopsy; Axon; Brain; Cell Survival; Cells; Code; Compensation; Complement; Complementary DNA; Cytoplasm; Denervation; Development; Disease; Disease Progression; Electrophysiology (science); Fiber; 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; Neuronal Plasticity; Neurons; Onset of illness; Paralysed; Pathogenesis; Pathologic; Pathway interactions; Patients; Pattern; Physiology; Population; Predisposition; Preparation; Process; Protein Secretion; Proteins; RNA; Recovery; Resistance; Sampling; Series; Silver; Spinal Cord; Synapses; Techniques; Time; Tissues; Tracer; Transforming Growth Factor Beta 2; Transgenes; adeno-associated viral vector; comparison control; coping; 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; neuronal survival; overexpression; pharmacologic; prevent; protein TDP-43; protein expression; reinnervation; resilience; response; restoration; sciatic nerve; sporadic amyotrophic lateral sclerosis; therapeutic target; therapy development; tibialis anterior muscle; timeline; 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.

项目总结/摘要 在大脑受伤后，与受损区域相邻的健康神经元有时可能会 受损神经元的功能。这一过程在急性神经损伤后得到了最好的研究。 损伤，但有证据表明，通过幸存的神经元补偿也发生在早期阶段， 神经退行性疾病在肌萎缩侧索硬化症（ALS）中，肌肉样本中的纤维类型分组 从病人身上提取的数据表明，在运动神经元（MN）和肌肉之间的连接最初丧失后， 新的神经能够重新连接，使患者能够在疾病过程中保持运动。第二 在尸检时观察到，绝大多数患者都有一种 一种叫做TDP-43的错误定位蛋白。然而，由于这些细胞在早期无法进入， 疾病阶段，在MN中应对疾病过程的分子机制， 与肌肉的联系尚不清楚。为了确定可能允许一个 MN的亚群专门科普错误定位的TDP-43，并发出新的轴突连接， 为了防止肌肉瘫痪，我们开发了一种小鼠模型，在这种模型中，我们可以诱导神经元表达 错误定位的人TDP-43，称为rNLS 8小鼠。然后，我们发现rNLS 8小鼠具有某些MN亚群， 这些细胞特别容易受到疾病的影响，而且存活的MNs甚至可以有效地取代这些细胞 在病程的后期。 在这项研究中，我们现在将确定负责神经再支配和恢复的MN群体。 在初始TDP-43触发MN损失后脆弱肌肉的功能（目的1），使用神经元和神经元的组合， 追踪技术、肌肉生理学和神经肌肉接头成像。然后我们将寻找 大脑免疫细胞小胶质细胞对MN可塑性的上游贡献以及由此产生的回路变化 (Aim 2）通过快速消除小胶质细胞并选择性地重新引入小胶质细胞衍生因子， 已经被证明会影响神经元的功能。最后，MN之间的分子差异， 在TDP-43触发轴突死亡之前和之后，神经支配相同的肌肉将被RNA- 将验证测序和顶级基因靶点对ALS样疾病期间运动功能的影响 在rNLS 8小鼠中（Aim 3）。这些研究的完成应该提供有价值的见解的潜力 MN亚群可耐受细胞质TDP-43积聚的机制。此外，理解 神经元补偿机制可以开发旨在支持的疗法 存活的细胞，以延长其天然可塑性，以减缓疾病并维持患者的功能。