Nuclear pore complex quality control in ALS/FTD

ALS/FTD 中核孔复合物的质量控制

• 批准号: 10393661
• 负责人: Charles Patrick Lusk
• 金额: $ 77.24万
• 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: 2021-05-01 至 2026-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10393661
• 关键词: ALS patients; Accounting; Alzheimer' s Disease; Amyotrophic Lateral Sclerosis; Antisense Oligonucleotide Therapy; Antisense Oligonucleotides; Autopsy; Biochemical; Biological Assay; Brain; C9ORF72; Cell Line; Clinical; Complex; Data; Defect; Degradation Pathway; Dementia; Disease; Disease Pathway; Event; Excision; Genes; Genetic Transcription; Homeostasis; Human; Huntington Disease; Impairment; Individual; Injury; Investigation; Lead; Link; Mammalian Cell; Mediating; Molecular; Nature; Nerve Degeneration; Neurodegenerative Disorders; Neurons; Nuclear; Nuclear Envelope; Nuclear Export; Nuclear Pore; Nuclear Pore Complex; Nuclear Pore Complex Proteins; Nucleoplasm; Pathogenesis; Pathologic; Pathway interactions; Patients; Peptides; Pharmacology; Phenotype; Proteins; Quality Control; RNA; RNA metabolism; Series; Spinal; Work; Yeasts; base; disease-causing mutation; experimental study; frontotemporal lobar dementia-amyotrophic lateral sclerosis; genetic manipulation; human tissue; imaging approach; individual patient; induced pluripotent stem cell; knock-down; molecular imaging; novel; nucleocytoplasmic transport; sporadic amyotrophic lateral sclerosis; stressor; therapeutic candidate; therapeutic target

PROJECT SUMMARY/ABSTRACT Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD), the second most common form of dementia, comprise a spectrum of fatal neurodegenerative diseases. An intronic GGGGCC (G4C2) hexanucleotide repeat expansion (HRE) in the C9orf72 gene, have been linked to ALS and FTD, although clinically two distinct diseases. The C9orf72 HRE is the most common cause of both familial and sporadic ALS accounting for ~40% and ~8% of patients respectively. Overall, about 10% of ALS cases are familial with the remaining 90% being sporadic. The molecular mechanisms underlying disease pathogenesis remain poorly understood. Defects in nucleocytoplasmic transport (NCT) and the nuclear pore complex (NPC) have recently emerged as a prominent pathomechanism underlying multiple neurodegenerative diseases including C9orf72 ALS/FTD, subsets of sporadic ALS, Alzheimer’s Disease, and Huntington’s Disease. However, little is known about the nature of the injury to the NPC and its individual nucleoporin components themselves. Using induced pluripotent stem cell derived spinal neurons (iPSNs) and postmortem human tissue, we have amassed data that loss of the transmembrane nucleoporin POM121 from NPCs initiates a pathological cascade impacting NPC composition, function and downstream cellular survival. Notably, loss of POM121 is mediated by pathologic G4C2 repeat RNA and not dipeptide repeat poly peptides or loss of C9ORF72 protein. Given that POM121 protein is not mislocalized and POM121 RNA metabolism is unaltered, we hypothesized that POM121 and subsequently altered nucleoporin proteins are aberrantly degraded in the early stages of C9orf72 ALS/FTD pathogenesis. Recent work in yeast and non-neuronal mammalian cells has shown that nuclear CHMP7 “activates” ESCRT-III mediated degradation of nuclear pore complexes and nuclear envelope components during nuclear pore surveillance and homeostasis. Our new preliminary data suggests that the loss of POM121 from the nucleoplasm and NPCs is initiated by nuclear accumulation of CHMP7. Mechanistically, increased nuclear CHMP7 appears to be the result of G4C2 repeat RNA mediated impaired nuclear export. Thus, our data strongly implicate a CHMP7 degradative pathway in disease pathogenesis. Intriguingly, knockdown of CHMP7 mitigates NPC injury in C9orf72 iPSNs making CHMP7 an attractive therapeutic target in neurodegeneration. In this proposal we will comprehensively investigate this new pathway including studies to 1) Determine the degradative pathway by which CHMP7 mediates nucleoporin removal from NPCs in iPSNs, 2) Investigate the mechanism by which pathologic G4C2 repeat RNA initiates CHMP7 mediated NPC injury. And finally, 3) using a large battery of individual patient iPSN spinal neuron cell lines, evaluate the ability of CHMP7 antisense oligonucleotides to mitigate C9orf72 ALS/FTD and sporadic ALS mediated alterations in the nuclear pore complex and nucleocytoplasmic transport and downstream sensitivity to stressors in iPSNs.

项目概要/摘要 肌萎缩侧索硬化症 (ALS) 和额颞叶痴呆 (FTD) 是第二种最常见的疾病 痴呆症包括一系列致命的神经退行性疾病。内含子 GGGGCC (G4C2) C9orf72 基因中的六核苷酸重复扩增 (HRE) 已与 ALS 和 FTD 相关，尽管 临床上两种不同的疾病。 C9orf72 HRE 是家族性和散发性 ALS 的最常见原因 分别占患者的约40%和约8%。总体而言，大约 10% 的 ALS 病例与家族有关 其余90%是零星的。疾病发病机制的分子机制仍不清楚 明白了。最近，核细胞质运输（NCT）和核孔复合物（NPC）的缺陷 成为包括 C9orf72 在内的多种神经退行性疾病的重要病理机制 ALS/FTD、散发性 ALS、阿尔茨海默病和亨廷顿病的子集。然而，鲜为人知 关于 NPC 损伤的性质及其各个核孔蛋白成分本身。使用诱导 多能干细胞衍生的脊髓神经元（iPSN）和死后人体组织，我们积累了数据 NPC 中跨膜核孔蛋白 POM121 的丢失会引发病理级联反应，影响 NPC 组成、功能和下游细胞存活。值得注意的是，POM121 的丢失是由 病理性 G4C2 重复 RNA 而不是二肽重复多肽或 C9ORF72 蛋白丢失。鉴于 POM121 蛋白没有错误定位，POM121 RNA 代谢也没有改变，我们假设 POM121 和随后改变的核孔蛋白在 C9orf72 的早期阶段异常降解 ALS/FTD 发病机制。最近在酵母和非神经元哺乳动物细胞中的研究表明，核 CHMP7“激活”ESCRT-III介导的核孔复合物和核膜降解 核孔监视和稳态过程中的成分。我们的新初步数据表明 POM121 从核质和 NPC 中的丢失是由 CHMP7 的核积累引发的。 从机制上讲，核 CHMP7 增加似乎是 G4C2 重复 RNA 介导受损的结果 核出口。因此，我们的数据强烈暗示 CHMP7 降解途径与疾病发病机制有关。 有趣的是，CHMP7 的敲低减轻了 C9orf72 iPSN 中的 NPC 损伤，使 CHMP7 成为有吸引力的选择 神经退行性疾病的治疗目标。在本提案中，我们将全面研究这条新途径 包括以下研究： 1) 确定 CHMP7 介导核孔蛋白去除的降解途径 来自 iPSN 中的 NPC，2) 研究病理性 G4C2 重复 RNA 启动 CHMP7 的机制 介导 NPC 损伤。最后，3) 使用大量个体患者 iPSN 脊髓神经元细胞系， 评估 CHMP7 反义寡核苷酸减轻 C9orf72 ALS/FTD 和散发性 ALS 的能力 介导核孔复合体和核细胞质运输以及下游敏感性的改变 iPSN 中的压力源。