Effects of Aging on Neuronal Lysosomal Damage Responses Driven by CMT2B-linked Rab7

衰老对 CMT2B 相关 Rab7 驱动的神经元溶酶体损伤反应的影响

基本信息

批准号：
10678789
负责人：
Ryan J Mulligan
金额：
$ 3.66万
依托单位：
UNIVERSITY OF VIRGINIA
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-04-01 至 2027-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10678789
关键词：
ARHGEF5 gene Acceleration Acute Address Affect Age Aging Alleles Alzheimer&apos s Disease Amputation Apoptosis Autophagocytosis Binding Brain Cell Death Cell Membrane Permeability Cells Cessation of life Charcot-Marie-Tooth Disease Complex Cytosol Data Disease Distal Endosomes Enzymes Esters Event Exhibits Exposure to Extravasation GTP Binding Galectin 3 Goals Guanosine Triphosphate Guanosine Triphosphate Phosphohydrolases Health Heterozygote Hour Human Hyperactivity Image Intraventricular Lead Leucine Link Lipofuscin Longevity Lysosomes Maintenance Mediating Membrane Monitor Monomeric GTP-Binding Proteins Motor Mus Mutation Nature Nervous System Neurodegenerative Disorders Neuroglia Neuronal Dysfunction Neurons Organelles Organism Pathology Pathway interactions Patients Peripheral Nervous System Diseases Population Process Property Proteins Proteome Proteomics Quality of life Role Sensory Slice Sorting Stress Stroke Synapsins System Tamoxifen Testing Therapeutic Ulcer Work age effect age related aged aging population cell motility cell type design experimental study first responder late endosome lysosomal proteins mutant nervous system disorder neurological pathology neuronal cell body neuropathology novel novel therapeutic intervention postmitotic prevent protective pathway protein degradation proteostasis proteotoxicity recruit repaired response sensor tau Proteins

项目摘要

Project Summary/Abstract The endosomal-lysosomal system is responsible for cellular protein degradation, and thus for protein homeostasis (proteostasis) in all cells. Neurons are spatially complex, large cell types, and must survive for the lifetime of an organism. This makes maintenance of the neuronal proteome unusually challenging. Disruption of lysosomal protein degradation can lead to accumulation of toxic aggregates, neuronal dysfunction, and death. Normal protein degradation can be disrupted via direct damage to lysosomes, which leads to leakage of luminal lysosomal contents into the cytosol in a process known as lysosomal membrane permeabilization (LMP), which can facilitate cell death. LMP is often causally linked to neurological pathologies that disproportionately affect aging populations. Even though lysosomes are critical to neuronal proteostasis, the response of neurons to LMP on a mechanistic level is poorly understood. Further, despite the intimate relationship between endosomal and lysosomal function, the role of endosomes in LMP responses is unknown. The small GTPase Rab7 is a master regulator of late endosomes and lysosomes. It is also critical for autophagy. Mutations in Rab7 lead to Charcot Marie-Tooth 2B (CMT2B) disease, a progressive peripheral neuropathy. My preliminary data suggest that Rab7 is an acute responder to LMP. Following LMP, Rab7 accumulates on various enlarged vesicular compartments, including late endosomes (LEs) and lysosomes (Lys), in a hyperactive, GTP-bound state. Within neurons, this response is exclusively localized to the soma. In this proposal, I aim to discover (1) the requirement of Rab7 activation for downstream LMP responses, such as galectin-3 accumulation on Lys and enlargement of LEs, (2) the impact of CMT2B mutant alleles on known LMP responses and Rab7 activation post LMP induction, and (3) the impact of age on Rab7 mediated neuronal degradation and LMP responses. I posit that Rab7 activation is essential in coordinating early responses for endosomal damage control in LMP. I will test the hypothesis that Rab7 activation following LMP is an essential response that mediates a protective pathway in neurons, which is disrupted in CMT2B mutant alleles. In Aim 1, I will explore the necessity of Rab7 activation in (1) galectin-3 mediated lysophagy and (2) LE vacuolization in response to LMP. In Aim 2, I will test whether Lys/LE responses and Rab7 activation in response to LMP are impacted in CMT2B. In Aim 3, I will determine whether aging disrupts Rab7 mediated (1) cargo degradation and (2) LMP responses in wild- type and mutant CMT2B neurons. Together, these experiments will determine homeostatic mechanisms in neurons that address lysosomal insults and whether this is impacted in disease. My long-term goal is to discover and characterize compensatory endosomal response mechanisms to lysosomal disruptions in LMP that will be broadly applicable to neurological disorders for the ultimate design of better therapeutics.

项目摘要/摘要内体 - 溶菌体系统负责细胞蛋白质降解，因此，对于所有细胞中的蛋白质稳态（蛋白质稳定）。神经元在空间上是复杂的，大细胞类型，并且必须在生物体的一生中生存。这使维护神经元蛋白质组异常地具有挑战性的。溶酶体蛋白降解的破坏会导致有毒骨料积累，神经元功能障碍和死亡。正常蛋白质降解可以通过直接损害溶酶体来破坏，而溶酶体在称为溶酶体膜的过程中导致腔溶酶体含量泄漏到细胞质中通透性（LMP），可以促进细胞死亡。 LMP通常与神经病理学有关这不成比例地影响老龄化人群。即使溶酶体对神经元蛋白质症至关重要，但神经元在机械水平上对LMP的反应知之甚少。此外，尽管很亲密内体和溶酶体功能之间的关系，内体在LMP反应中的作用尚不清楚。小型GTPase RAB7是晚期内体和溶酶体的主要调节剂。这也是至关重要的自噬。 Rab7的突变导致Charcot Marie-Tooth 2b（CMT2B）疾病，一种进行性周边神经病。我的初步数据表明RAB7是对LMP的急性响应者。遵循LMP，RAB7 积聚在各种扩大的囊泡室，包括晚期内体（LES）和溶酶体（LYS），以GTP结合的过度活跃状态。在神经元内，这种反应仅本地化为soma。在这个提案，我旨在发现（1）RAB7激活对下游LMP响应的要求，例如 Galectin-3在LYS上积累和LES的扩大，（2）CMT2B突变等位基因对已知LMP的影响 LMP诱导后的反应和RAB7激活，以及（3）年龄对RAB7介导的神经元的影响降解和LMP响应。我认为Rab7激活对于协调早期响应至关重要 LMP中的内体损伤控制。我将检验以下假设：LMP之后的Rab7激活是介导A的必要反应神经元中的保护途径，该途径在CMT2B突变等位基因中被破坏。在AIM 1中，我将探讨必要性（1）Galectin-3介导的溶液和（2）响应LMP的Rab7激活。在AIM 2中，我将测试LYS/LE响应和RAB7对LMP的激活是否受到CMT2B的影响。在AIM 3中，我将确定衰老是否会破坏RAB7介导的（1）货物降解和（2）野生中的LMP反应类型和突变CMT2B神经元。这些实验将共同确定稳态机制解决溶酶体侮辱以及是否对疾病影响的神经元。我的长期目标是发现并表征对LMP中溶酶体干扰的代偿性内体反应机制广泛适用于神经系统疾病，以实现更好的治疗剂的最终设计。