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.

项目总结/摘要 肌萎缩性侧索硬化症（ALS）和额颞叶痴呆（FTD），第二种最常见的形式， 痴呆症包括一系列致命的神经变性疾病。内含子GGGGCC（G4 C2） C9 orf 72基因中的六核苷酸重复扩增（HRE）与ALS和FTD有关，尽管 临床上两种不同的疾病。C9 orf 72 HRE是家族性和散发性ALS的最常见原因 分别占患者的40%和8%。总的来说，大约10%的ALS病例是家族性的， 剩下的90%是零星的。疾病发病机制的分子机制仍然很差 明白核质转运（NCT）和核孔复合体（NPC）的缺陷， 作为多种神经退行性疾病（包括C9 orf 72）的重要病理机制出现 ALS/FTD、散发性ALS亚组、阿尔茨海默病和亨廷顿病。然而， 关于NPC损伤的性质及其单个核孔蛋白组分本身。使用诱导 多能干细胞衍生的脊髓神经元（iPSNs）和死后人体组织，我们已经积累了数据 NPCs跨膜核孔蛋白POM 121的缺失引发了一个病理性级联反应， NPC组成、功能和下游细胞存活。值得注意的是，P0 M121的损失是由以下介导的： 病理性G4 C2重复RNA而非二肽重复多肽或C9 ORF 72蛋白缺失。鉴于 POM 121蛋白没有错误定位，POM 121 RNA代谢没有改变，我们假设， POM 121和随后改变的核孔蛋白在C9 orf 72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， CHMP 7“激活”ESCRT-III介导的核孔复合物和核膜的降解 在核孔监视和稳态过程中的组分。我们新的初步数据表明， POM 121从核质和NPC的丢失是由CHMP 7的核积累引发的。 从机制上讲，增加的核CHMP 7似乎是G4 C2重复RNA介导的受损的结果。 核出口。因此，我们的数据强烈暗示了疾病发病机制中的CHMP 7降解途径。 有趣的是，CHMP 7的敲除减轻了C9 orf 72 iPSN中的NPC损伤，使得CHMP 7成为一种有吸引力的 神经变性的治疗靶点。在本提案中，我们将全面研究这一新途径 包括以下研究：1）确定CHMP 7介导核孔蛋白去除的降解途径 2）研究病理性G4 C2重复RNA启动CHMP 7的机制 介导NPC损伤。最后，3）使用大量的个体患者iPSN脊髓神经元细胞系， 评价CHMP 7反义寡核苷酸减轻C9 orf 72 ALS/FTD和散发性ALS的能力 介导的核孔复合体和核质转运及下游敏感性的改变 在iPSNs的压力源。