Preclinical models and therapies for myotonic dystrophy type 2

2 型强直性肌营养不良的临床前模型和治疗

基本信息

批准号：
10021457
负责人：
CHARLES A THORNTON
金额：
$ 23.12万
依托单位：
UNIVERSITY OF ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-09-30 至 2023-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10021457
关键词：
3&apos Untranslated Regions ACTA1 gene Actins Address Adult Aging Animal Model Antisense Oligonucleotides Biology Brain C9ORF72 CUG repeat Cell Nucleus Characteristics Clinical Clinical Trials Consensus Sequence Cornea Data Development Disease Electroporation Exons Family Frontotemporal Dementia Fuchs&apos Endothelial Dystrophy Genes Genetic Genetic Transcription Human Infant Inflammation Injury Introns Location Methods Modeling Mus Muscle Muscular Dystrophies Mutation Myopathy Myotonia Myotonic dystrophy type 1 Myotonic dystrophy type 2 Nerve Degeneration Neuraxis Nuclear Pathogenicity Pathology Patients Pattern Peptides Pharmaceutical Preparations Phenotype Poly A Population Pre-Clinical Model Process Production Property Proteins RNA RNA-Binding Proteins Research Site Skeletal Muscle TCF7L2 gene Testing Therapeutic Therapeutic Effect Therapeutic Studies Toxic effect Transgenes Transgenic Mice Translation Initiation Translational Research Translations Untranslated RNA congenital myopathy design effective therapy follow-up in vivo knock-down metabolic abnormality assessment mouse model muscle stress nucleic acid binding protein pre-clinical therapy process repeatability skeletal small molecule small molecule therapeutics targeted therapy trials targeted treatment therapeutic development transcriptome transcriptomics

项目摘要

Myotonic dystrophy type 2 (DM2) is an autosomal dominant form of muscular dystrophy, resulting from expansion of a CCTG repeat in CNBP, the gene encoding Cellular Nucleic Acid Binding Protein. The discovery of the DM2 mutation provided critical support for the concept that expanded repeats in non-coding regions give rise to dominant acting RNAs. A unifying model for RNA toxicity in myotonic dystrophy type 1 (DM1), DM2, and potentially other repeat expansion diseases is that RNA binding proteins are sequestered by expanded RNA repeats, giving rise to pervasive changes in the transcriptome when the functions of RNA binding proteins are lost. However, 3 of the 4 commonest RNA dominant diseases result from repeat expansions in introns. Once transcribed, introns are rapidly excised and degraded, therefore the concept that intronic repeats act as a sink for RNA binding proteins seems implausible. More surprisingly, recent studies also indicate that intronic expanded repeats in patients with DM2 or familial ALS undergo translation in the central nervous system, through a process of Repeat Associated Non-AUG (RAN) translation, resulting in production of deleterious tetra- or di-peptide repeat proteins. Whether this occurs in skeletal muscle has not been determined. Therapeutic development for DM1 has advanced rapidly, but has hardly begun for DM2, partly due to the lack of animal models. DM1 and DM2 many share many clinical features, but also have important differences. For example, DM1 often effects skeletal muscle in infants, leading to congenital myopathy, but this does not occur in DM2. In Aim 1 of this proposal we have developed transgenic mouse models of DM2, that express expanded CCUG repeat (CCUGexp) RNA in an intron or in the 3′ untranslated region. To better understand differences between DM1 and DM2, we will use these models, and previous models for DM1, to compare toxicities and transcriptomic effects of expanded RNA repeats in introns versus exons, and the relative toxicities of CCUG versus CUG repeats. We will also study the metabolism of intronic RNA repeats. In particular, we will follow up on preliminary data suggesting that processing of an intron containing expanded CCUG repeats is altered, leading to intron retention. In Aim 2 we will determine the conditions under which RAN translation of intronic CCUGexp RNA occurs in skeletal muscle in vivo. Using transgenic mice, and an electroporation model for transient expression of CCUGexp RNA, we will quantify RAN translation, and test the hypothesis that RAN translation is promoted or pre-conditioned by muscle stress. Finally in Aim 3 we will study therapeutic effects in the new mouse models, using antisense oligonucleotide and small molecule drugs. Overall, this project will clarify mechanisms important to DMpathogenesis and initiate the process of therapeutic development for DM2.

强直性肌营养不良 2 型 (DM2) 是一种常染色体显性遗传的肌营养不良症，由 CNBP 中 CCTG 重复序列的扩展，CNBP 是编码细胞核酸结合蛋白的基因。 DM2 突变的研究为非编码区重复序列扩展的概念提供了关键支持引起强直性肌营养不良 1 型 (DM1) 中 RNA 毒性的统一模型， DM2 和其他潜在的重复扩增疾病是 RNA 结合蛋白被隔离 RNA 重复序列扩展，当 RNA 的功能发挥作用时，转录组会发生普遍变化然而，4 种最常见的 RNA 显性疾病中有 3 种是由重复引起的。内含子一旦转录，就会被迅速切除和降解，因此有这样的概念：更令人惊讶的是，最近的研究表明，内含子重复序列充当 RNA 结合蛋白的接收器似乎不太可信。还表明 DM2 或家族性 ALS 患者的内含子扩展重复序列在中枢神经系统，通过重复相关非 AUG (RAN) 翻译过程，产生有害的四肽或二肽重复蛋白的产生是否发生在骨骼肌中尚未确定。 DM1 的治疗开发进展迅速，但 DM2 的治疗开发尚未开始，部分由于缺乏动物模型，DM1和DM2有许多共同的临床特征，但也有。例如，DM1 经常影响婴儿的骨骼肌，导致先天性畸形。肌病，但这不会发生在 DM2 中。在该提案的目标 1 中，我们开发了转基因小鼠。 DM2 模型，在内含子或 3' 非翻译区表达扩展的 CCUG 重复 (CCUGexp) RNA 为了更好地理解 DM1 和 DM2 之间的差异，我们将使用这些模型以及之前的模型。 DM1 模型，比较内含子中扩展 RNA 重复序列与外显子，以及 CCUG 与 CUG 重复序列的相对毒性我们还将研究内含子的代谢。特别是，我们将跟进表明内含子加工的初步数据。含有 CCUG 重复的扩展被改变，导致内含子保留。在目标 2 中，我们将确定内含子 CCUGexp RNA 的 RAN 翻译在体内骨骼肌中发生的条件。转基因小鼠和 CCUGexp RNA 瞬时表达的电穿孔模型，我们将量化 RAN 翻译，并测试 RAN 翻译是由肌肉促进或预先调节的假设最后，在目标 3 中，我们将使用反义研究新小鼠模型的治疗效果。总的来说，该项目将阐明对寡核苷酸和小分子药物很重要的机制。 DM 发病机制并启动 DM2 治疗开发过程。