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: 10282471
• 负责人: Alyssa Coyne
• 金额: $ 13.01万
• 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 2022-07-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10282471
• 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）和额颞叶痴呆症（FTD）包括一系列破坏性和致命的神经退行性疾病。虽然超过20个基因位点与ALS和FTD相关，但约90%的ALS病例本质上是散发性的。最近的研究已经确定核孔复合体（NPC）和核质转运（NCT）的改变是家族性和散发性ALS的重要病理机制。然而，这些病理性破坏的分子机制仍然是未知的。我们最近的研究已经确定，在C9 orf 72 iPSN和死后患者神经元细胞核中，来自NPC的八种核孔蛋白（Nups）存在可再现的和稳健的减少。最近的工作表明，ESCRT-III途径在监视和维持酵母中正确组装和发挥功能的NPC中起着重要作用。重要的是，在这些非CNS系统中的工作表明，CHMP 7向核膜的募集引发下游事件，导致NUP和NPC的降解。事实上，在C9 orf 72人神经元中来自NPC的Nup的减少似乎是CHMP 7和ESCRT-III介导的降解途径的异常激活的结果，而不是Nup错误定位或Nup mRNA代谢改变的结果。然而，关于这些最初的发现与更常见的散发性ALS（sALS）的关系，实际上知之甚少。在sALS iPSC衍生的脊髓神经元的子集上使用超分辨率结构照明显微镜（SIM），我们已经产生了初步数据，其强烈表明NPC和Nup缺陷是sALS中的普遍病理。值得注意的是，在迄今为止检查的约50%的sALS iPSN和死后运动皮层样品中，我们还观察到稳健的CHMP 7病理学，这让人想起我们在C9 orf 72 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途径的异常激活可能是NPC、NCT和总体细胞存活中断的重要因素，从而突出了CHMP 7作为ALS和以NPC损伤为特征的相关神经退行性疾病的治疗靶标的潜力。在这里，我们将使用iPSNs和死后的人CNS组织来全面定义sALS发病机制中个体NUP和NPC的改变（目的1）。此外，我们将评估CHMP 7和异常ESCRT-III介导的降解对sALS中NPC损伤的贡献（目的2）。最后，我们将定义CHMP 7被病理性“激活”以引发sALS中NPC损伤的机制（目的3）。总的来说，这些实验将显着推进我们对人类神经元和sALS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，拟定研究将为未来研究CHMP 7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。