Nuclear pore complex quality control in ALS/FTD

ALS/FTD 中核孔复合物的质量控制

• 批准号: 10615677
• 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/10615677
• 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; Image; Impairment; Individual; Injury; Investigation; Link; Mammalian Cell; Mediating; Membrane; 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; Phenotype; Proteins; Quality Control; RNA; RNA metabolism; Series; Spinal; Vertebral column; Work; Yeasts; disease-causing mutation; efficacy evaluation; experimental study; frontotemporal lobar dementia amyotrophic lateral sclerosis; genetic manipulation; human tissue; imaging approach; individual patient; induced pluripotent stem cell; knock-down; novel; nucleocytoplasmic transport; pharmacologic; 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.

项目摘要/摘要 肌萎缩性侧索硬化症（ALS）和额颞痴呆（FTD），第二种最常见的形式 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张（HRE）已与ALS和FTD相关，尽管 临床上两种不同的疾病。 C9orf72 hre是家庭和零星ALS的最常见原因 分别为约40％和约8％的患者。总体而言，约有10％的ALS病例是 剩下的90％是零星的。疾病发病机理的分子机制仍然很差 理解。核眼质运输（NCT）和核孔复合物（NPC）缺陷已有 成为一种重要的多种神经退行性疾病（包括C9ORF72）的突出的病理机制 ALS/FTD，零星ALS的亚集，阿尔茨海默氏病和亨廷顿氏病。但是，鲜为人知 关于NPC及其单个核元组件本身的伤害的性质。使用诱导 多能干细胞衍生的脊柱神经元（IPSN）和验尸后人体组织，我们已经积累了数据 NPC中跨膜核Porin POM121的损失启动了病理级联 NPC组成，功能和下游细胞存活。值得注意的是，POM121的损失是由 病理G4C2重复RNA，而不是二肽重复多肽或C9ORF72蛋白的丧失。鉴于 POM121蛋白不会误定位，POM121 RNA代谢没有改变，我们假设 POM121并随后改变的核孔蛋白蛋白在C9orf72的早期阶段异常降解 ALS/FTD发病机理。最近在酵母和非神经哺乳动物细胞中的工作表明核 CHMP7“激活” ESCRT-III介导的核孔复合物和核包膜的降解 核孔监测和稳态期间的组件。我们的新初步数据表明 CHMP7核积累中POM121的损失。 从机械上讲，增加的核CHMP7似乎是G4C2重复RNA介导的受损的结果 核出口。这是我们的数据强烈暗示疾病发病机理中CHMP7降解途径。 有趣的是，CHMP7的敲低减轻C9ORF72 IPSN中的NPC损伤，使CHMP7成为吸引人 神经退行性中的治疗靶标。在此提案中，我们将全面研究这一新途径 包括到1）确定CHMP7介导核孔的降解途径的降解途径 来自IPSN中的NPC，2）研究病理G4C2重复RNA启动CHMP7的机制 介导的NPC损伤。最后，3）使用大量的单个患者IPSN脊柱神经元细胞系， 评估CHMP7反义寡核苷酸减轻C9ORF72 ALS/FTD和零星ALS的能力 核孔复合物和核眼质转运和下游灵敏度的介导的改变 给IPSN中的压力源。