Understanding SHRF, an RNA exosome-linked disease with multi-organ involvement

了解 SHRF，一种与 RNA 外泌体相关的多器官受累疾病

• 批准号: 10305689
• 负责人: Bingwei Lu
• 金额: $ 23.61万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-12-01 至 2022-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10305689
• 关键词: 9q34; Address; Affect; Animal Model; Atrophic; Autophagocytosis; Biological Models; Biology; Birth; Brain imaging; Cell Culture Techniques; Cell Nucleus; Cell model; Cell physiology; Cerebellar Cortex; Chromosomes; Complex; Defect; Dentate nucleus; Disease; Disease model; Drosophila genus; Engineering; Enzymes; Eukaryotic Cell; Exhibits; Face; Facies; Funding Opportunities; Genes; Genetic; Genomics; Hearing; Human; Inferior; Institutes; Intellectual functioning disability; KH Domain; Knowledge; Label; Lead; Light; Link; Maintenance; Malignant Neoplasms; Mammalian Cell; Mission; Modeling; Muscle; Mutation; Neonatal; Neurodegenerative Disorders; Neurons; Olives - dietary; Pathogenesis; Patients; Peroxidases; Pontine structure; Pontocerebellar hypoplasia; Positioning Attribute; Post-Transcriptional Regulation; Process; Proteins; Pulmonary Fibrosis; RNA; RNA Binding; RNA-Binding Proteins; Regulation; Research; Retinitis Pigmentosa; Rewards; Ribonucleases; Risk; Role; Signal Pathway; Structure; Testing; Tissues; Transcript; United States National Institutes of Health; Visual; Visual impairment; ascorbate; base; body system; cell type; disease phenotype; exosome; experience; fetal; fly; hearing impairment; in vivo; induced pluripotent stem cell; insight; keratinocyte; myelination; nervous system development; new technology; novel; scaffold

Project Summary Short stature, hearing loss, retinitis pigmentosa, and distinctive facies (SHRF) is a rare autosomal recessive disorder characterized by short stature, brachydactyly, dysmorphic facial features, hearing loss, and visual impairment. Patients also exhibit mild intellectual disability. SHRF is caused by homozygous or compound heterozygous mutation in the EXOSC2 gene, which encodes a subunit of the RNA exosome complex, a conserved multi-subunit ribonucleolytic complex that controls the 3´ to 5´ processing and degradation of various RNAs in all eukaryotic cells. Nine subunits (EXOSC1-9) form a catalytically inert core that serves as a scaffold for two ribonuclease subunits (EXOSC10 and Dis3). EXOSC2 and EXOSC3 are S1 and KH domain containing RNA-binding proteins that form the exosome cap structure. Intriguingly, despite the sequence similarity and similar positions in the exosome structure occupied by EXOSC2 and EXOSC3, mutations in these subunits result in distinct diseases, with mutations in EXOSC2 causing SHRF and mutations in EXOSC3 causing Pontocerebellar Hypoplasia type 1b (PCH1b), a rare autosomal recessive neonatal/fetal neurodegenerative disease characterized by hypoplasia and atrophy of the cerebellar cortex, dentate nuclei, pontine nuclei and inferior olives. That mutation in core subunits of a seemingly universally required RNA exosome complex can result in distinct diseases reflects inherent complexity in the organization, function, and regulation of this fundamental machinery of post-transcriptional gene regulation. But our understanding of the mechanistic basis underlying these processes is very limited. We hypothesize that RNA exosome subunits are assembled into different subcomplexes with different RNA substrate engagements, and that these subcomplexes may function in a tissue or cell type-specific manner. To test this hypothesis, we propose to employ the recently developed proximity labeling using the engineered enzyme ascorbate peroxidase 2 (APEX2) to systematically identify proteins and RNAs in the immediate proximity of EXOSC2 in mammalian cell culture models, including iPSC-derived neuronal and muscle models, and in vivo Drosophila models. The functional involvement of newly identified factors in exosome biology and SHRF pathogenesis will be tested in Drosophila models. Successful execution of this project will not only lead to new knowledge on the composition, regulation, and tissue-specific requirement of the RNA exosome complex, but also shed light on the pathogenesis of RNA exosome-linked diseases, from SHRF, PCH, SMA and pulmonary fibrosis to cancer, diseases affecting multiple body systems. It is therefore expected that findings from this study will be applicable to the missions of multiple NIH Institutes or Centers (ICs), one of the stated Research Objectives of this R21 funding opportunity.

项目概要 身材矮小、听力损失、色素性视网膜炎和独特面容 (SHRF) 是一种罕见的常染色体隐性遗传病 以身材矮小、短指、面部特征畸形、听力丧失和视力丧失为特征的疾病 损害。患者还表现出轻度智力障碍。 SHRF是由纯合子或复合子引起的 EXOSC2 基因的杂合突变，该基因编码 RNA 外泌体复合物的一个亚基， 保守的多亚基核糖核酸复合物，控制 3' 至 5' 的加工和降解 所有真核细胞中都有不同的RNA。九个亚基 (EXOSC1-9) 形成催化惰性核心，充当 两个核糖核酸酶亚基（EXOSC10 和 Dis3）的支架。 EXOSC2和EXOSC3是S1和KH域 含有形成外泌体帽结构的RNA结合蛋白。有趣的是，尽管顺序 EXOSC2 和 EXOSC3 所占据的外泌体结构的相似性和相似位置，突变 这些亚基会导致不同的疾病，其中 EXOSC2 突变会导致 SHRF，而 EXOSC3 突变会导致 SHRF 导致脑桥小脑发育不全 1b 型 (PCH1b)，一种罕见的常染色体隐性遗传新生儿/胎儿 以小脑皮质、齿状核发育不全和萎缩为特征的神经退行性疾病， 脑桥核和下橄榄核。看似普遍需要的 RNA 核心亚基的突变 外泌体复合物可导致不同的疾病，反映了组织、功能和功能的固有复杂性 转录后基因调控这一基本机制的调控。但我们的理解是 这些过程背后的机械基础非常有限。我们假设 RNA 外泌体亚基是 组装成具有不同 RNA 底物接合的不同子复合物，并且这些 亚复合物可以以组织或细胞类型特异性的方式发挥作用。为了检验这个假设，我们建议 采用最近开发的邻近标记，使用工程酶抗坏血酸过氧化物酶 2 (APEX2) 系统地鉴定哺乳动物中 EXOSC2 附近的蛋白质和 RNA 细胞培养模型，包括 iPSC 衍生的神经元和肌肉模型，以及体内果蝇模型。这 新发现的因子在外泌体生物学和 SHRF 发病机制中的功能参与将在 果蝇模型。该项目的成功执行不仅会带来关于 RNA 外泌体复合物的组成、调节和组织特异性要求，同时也揭示了 RNA 外泌体相关疾病的发病机制，从 SHRF、PCH、SMA 和肺纤维化到癌症， 影响多个身体系统的疾病。因此，预计这项研究的结果将 适用于多个 NIH 研究所或中心 (IC) 的任务，其中规定的研究目标之一 这个 R21 融资机会。