Mechanisms of nuclear pore complex homeostasis and injury in ALS/FTD and related neurodegenerative diseases

ALS/FTD 及相关神经退行性疾病中核孔复合物稳态和损伤的机制

• 批准号: 10706361
• 负责人: Alyssa Coyne
• 金额: $ 24.9万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-15 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10706361
• 关键词: Amyotrophic Lateral Sclerosis; Antisense Oligonucleotides; Autopsy; Biochemical; Biology; C9ORF72; Cell Nucleus; Cellular Stress; Data; Defect; Degradation Pathway; Dementia; Disease; Event; Frontotemporal Dementia; Future; Genes; Homeostasis; Human; Image; Individual; Injury; Investigation; Lighting; Link; Maintenance; Mammalian Cell; Mediating; Membrane Proteins; Messenger RNA; Metabolism; Microscopy; Modeling; Molecular; Motor Cortex; Mutation; Nature; Nerve Degeneration; Neurodegenerative Disorders; Neurons; Nuclear Envelope; Nuclear Inner Membrane; Nuclear Pore; Nuclear Pore Complex; Nuclear Pore Complex Proteins; Pathogenesis; Pathogenicity; Pathologic; Pathology; Pathway interactions; Patients; Pharmacology; Play; Pore Proteins; Prevalence; Reproducibility; Resolution; Role; Sampling; Series; Spinal; Structure; System; Techniques; Testing; Tissue Model; Tissues; Work; Yeasts; base; cell type; env Gene Products; experimental study; exportin 1 protein; frontotemporal lobar dementia-amyotrophic lateral sclerosis; genetic manipulation; genomic locus; high resolution imaging; improved; induced pluripotent stem cell; insight; molecular subtypes; neuronal survival; new therapeutic target; novel; nucleocytoplasmic transport; programs; recruit; response; sporadic amyotrophic lateral sclerosis; therapeutic target

Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD) comprise a spectrum of devastating and fatal neurodegenerative diseases. While over 20 genetic loci have been linked to ALS and FTD, about 90% of ALS cases are sporadic in nature. Recent studies have identified alterations in the nuclear pore complex (NPC) and nucleocytoplasmic transport (NCT) as a prominent pathomechanism underlying familial and sporadic ALS. However, the molecular mechanisms underlying these pathologic disruptions remain largely unknown. Our recent studies have established that there is a reproducible and robust reduction of eight nucleoporins (Nups) from the NPC in C9orf72 iPSN and postmortem patient neuronal nuclei. Recent work suggests that the ESCRT-III pathway plays a fundamental role in the surveillance and maintenance of properly assembled and functioning NPCs in yeast. Critically, work in these non-CNS systems suggests that recruitment of CHMP7 to the nuclear envelope initiates downstream events leading to degradation of Nups and NPCs. Indeed, the reduction of Nups from the NPC in C9orf72 human neurons appears to be the result of aberrant activation of CHMP7 and ESCRT-III mediated degradation pathways and not the result of Nup mislocalization or alterations in Nup mRNA metabolism. However, little is actually known about how these initial discoveries relate to the far more common sporadic ALS (sALS). Using super resolution structured illumination microscopy (SIM) on a subset of sALS iPSC derived spinal neurons, we have generated preliminary data that strongly suggests NPC and Nup defects are a prevalent pathology in sALS. Notably, in about 50% of sALS iPSNs and postmortem motor cortex samples examined to date, we also observe robust CHMP7 pathology, reminiscent of our studies in C9orf72 ALS/FTD. Collectively, these early studies have led us to hypothesize that in human neurons, aberrant activation of the ESCRT-III pathway may be a substantial contributor to disruptions in the NPC, NCT, and overall cellular survival thus highlighting the potential for CHMP7 as a therapeutic target in ALS and related neurodegenerative diseases characterized by NPC injury. Here, we will use iPSNs and postmortem human CNS tissue to comprehensively define the alterations to individual Nups and NPCs in sALS pathogenesis (Aim 1). Furthermore, we will evaluate the contribution of CHMP7 and aberrant ESCRT-III mediated degradation to NPC injury in sALS (Aim 2). Finally, we will define the mechanism by which CHMP7 is pathologically “activated” to initiate NPC injury in sALS (Aim 3). Collectively, these experiments will significantly advance our understanding of the mechanisms underlying NPC homeostasis in human neurons and sALS disease and provide novel insights into potential new therapeutic targets. Moreover, the proposed studies will set the stage for future investigations into the role of CHMP7 and Nup degradation in the pathogenesis of FTD and other related neurodegenerative diseases.

肌萎缩侧索硬化症（ALS）和额颞叶痴呆（FTD）包括一系列毁灭性和致命的神经退行性疾病。虽然有20多个基因位点与ALS和FTD有关，但约90%的ALS病例本质上是散发的。最近的研究发现，核孔复合物（NPC）和核胞质转运（NCT）的改变是家族性和散发性ALS的重要病理机制。然而，这些病理破坏的分子机制在很大程度上仍然未知。我们最近的研究已经证实，在C9orf72 iPSN和死后患者的神经元核中，NPC中有8种核孔蛋白（Nups）可重复和显著减少。最近的研究表明，ESCRT-III通路在酵母中适当组装和功能的npc的监视和维持中起着重要作用。至关重要的是，在这些非中枢神经系统中的研究表明，CHMP7向核膜的募集启动了下游事件，导致Nups和NPCs的降解。事实上，C9orf72人类神经元NPC中Nup的减少似乎是CHMP7和ESCRT-III介导的降解途径异常激活的结果，而不是Nup错定位或Nup mRNA代谢改变的结果。然而，对于这些最初的发现与更常见的散发性肌萎缩侧索硬化症（sALS）之间的关系，实际上知之甚少。使用超分辨率结构照明显微镜（SIM）对sALS iPSC衍生的脊髓神经元子集进行观察，我们获得了初步数据，强烈表明NPC和Nup缺陷是sALS中普遍存在的病理。值得注意的是，在迄今为止检查的约50%的ALS ipsn和死后运动皮层样本中，我们还观察到强大的CHMP7病理，这让人想起我们在C9orf72 ALS/FTD中的研究。总的来说，这些早期研究使我们假设，在人类神经元中，ESCRT-III通路的异常激活可能是鼻咽癌、NCT和整体细胞存活中断的重要因素，从而突出了CHMP7作为ALS和以鼻咽癌损伤为特征的相关神经退行性疾病的治疗靶点的潜力。在这里，我们将使用ipsn和死后的人类中枢神经系统组织来全面定义单个nup和NPCs在sALS发病机制中的变化（目的1）。此外，我们将评估CHMP7和异常ESCRT-III介导的降解对sALS中鼻咽癌损伤的贡献（目的2）。最后，我们将定义CHMP7在脊髓侧索硬化症中病理“激活”引发鼻咽癌损伤的机制（目的3）。总的来说，这些实验将显著促进我们对人类神经元和als疾病中NPC稳态机制的理解，并为潜在的新治疗靶点提供新的见解。此外，拟议的研究将为未来研究CHMP7和Nup降解在FTD和其他相关神经退行性疾病发病机制中的作用奠定基础。