Understanding and Manipulating the Degradation of the C9orf72 Repeat Expansion RNA

了解和操纵 C9orf72 重复扩增 RNA 的降解

• 批准号: 10387697
• 负责人: Soraya I Shehata
• 金额: $ 3.91万
• 依托单位: UNIVERSITY OF COLORADO
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10387697
• 关键词: Adenosine; Affect; C9ORF72; Cell Nucleus; Cells; Cytoplasm; Degradation Pathway; Development; Dipeptides; Disease; Enzymes; Eukaryotic Cell; Excision; Exonuclease; Fellowship; Fluorescent in Situ Hybridization; Future; Genes; Genetic; Genetic Transcription; Goals; Inherited; Introns; Knowledge; Learning; Methods; Modification; Mutate; Mutation; Neurodegenerative Disorders; Neurons; Nuclear; Oligonucleotides; Pathogenesis; Pathologic; Patients; Persons; Phosphodiesterase I; Process; Proteins; RNA; RNA Decay; RNA Degradation; RNA Sequences; RNA-Binding Proteins; Resistance; Structure; Tail; Testing; Therapeutic; Therapeutic Intervention; Time; Toxic effect; Translating; Translations; Ubiquitination; Untranslated RNA; Uridine; Work; burden of illness; c9FTD/ALS; design; exosome; frontotemporal lobar dementia-amyotrophic lateral sclerosis; mRNA Precursor; neurotoxicity; novel therapeutic intervention; prevent; recruit; response

PROJECT SUMMARY/ABSTRACT Understanding and Manipulating the Degradation of the C9orf72 Repeat Expansion RNA Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are progressive, fatal neurodegenerative diseases. The most common cause of hereditary ALS and FTD is an expansion of the G4C2 sequence in an intron of the C9orf72 gene (c9ALS/FTD). A hallmark pathologic feature of c9ALS/FTD is the presence of repeat expansion RNA foci in neuronal nuclei, which is unusual because introns are usually degraded too rapidly to be easily detected. The accumulating G4C2 repeat expansion RNA is thought to contribute to c9ALS/FTD disease development in two ways: it can sequester RNA-binding proteins and disrupt their function, and it can be exported into the cytoplasm for translation into toxic dipeptide repeat proteins. The persistence of the repeat expansion RNA suggests that it forms a stable RNA structure that resists the normal intron degradation machinery. However, eukaryotic cells contain specific mechanisms for the degradation of RNAs with strong secondary structures. Such RNAs are post-transcriptionally modified with 3' oligo-uridine or oligo-adenosine tails that then recruit processive 3' to 5' exonucleases to degrade the RNA. I hypothesize that the C9orf72 repeat RNA is a poor substrate for normal intronic degradation pathways and that 3’ end tailing determines its rate of decay. To test this, the goal of this proposal is two-fold: I will determine the composition of the repeat expansion RNA that accumulates into nuclear foci to learn where intronic degradation is stalling (Aim 1), and I will examine the changes to the sequence and levels of the G4C2 repeat expansion RNA in response to perturbations to 3’ end tailing, tail removal, and RNA degradation (Aim 2). Taken together, these studies present an exciting opportunity to discover the mechanisms that promote degradation of the toxic repeat expansion RNA and, potentially, the ability to accelerate its decay to reduce toxicity. If successful, the knowledge gained from this work could guide future therapeutic design for c9ALS/FTD.

项目摘要/摘要 了解和操纵C9orf72重复扩展RNA的降解 肌萎缩性外侧硬化症（ALS）和额颞痴呆（FTD）是渐进的，致命的 神经退行性疾病。遗传ALS和FTD的最常见原因是G4C2的扩展 C9ORF72基因（C9ALS/FTD）内含子中的序列。 C9als/ftd的标志性病理特征是 神经元核中存在重复扩展RNA焦点，这是不寻常的，因为介绍通常是 降解太快而无法检测到。累积的G4C2重复扩展RNA被认为是 通过两种方式促进C9ALS/FTD疾病的发展：它可以隔离RNA结合蛋白并破坏 它们的功能，可以将其导出到细胞质中，以转化为有毒的二肽重复蛋白。 重复膨胀RNA的持久性表明它形成了一种稳定的RNA结构，可抵抗 正常内含子降解机械。但是，真核细胞包含特定机制 具有强次结构的RNA降解。此类RNA在转录后通过3'修改 寡尿尿或寡腺苷的尾巴，然后募集3'至5'外丝丝的过程以降解RNA。我 假设C9orf72重复RNA是正常内含子降解途径的较差的底物，并且 3'结束尾巴决定了其衰减速率。为了测试这一点，该提案的目标是两个方面：我将确定 重复膨胀RNA的组成，积聚在核灶中以学习内含子的位置 退化正在停滞（AIM 1），我将检查序列和水平的变化 G4C2重复膨胀RNA，响应3'末端尾巴，尾部去除和RNA降解 （目标2）。综上所述，这些研究提供了一个令人兴奋的机会，可以发现 促进有毒重复膨胀RNA的定义，并有可能加速其衰减的能力 降低毒性。如果成功，这项工作所获得的知识可以指导未来的治疗设计 C9als/ftd。