Pathogenic mechanisms and therapeutics for the cardiac manifestations of myotonic dystrophy type 1

1型强直性肌营养不良心脏表现的发病机制和治疗

• 批准号: 9915976
• 负责人: Thomas A Cooper
• 金额: $ 43.16万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-15 至 2023-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9915976
• 关键词: 3' Untranslated Regions; Adult; Affect; Alleles; Alternative Splicing; Arrhythmia; Binding; CUG repeat; Cardiac; Cardiac Myocytes; Cause of Death; Cell Culture Techniques; Cessation of life; Chimeric Proteins; DNA; Data Set; Disease; Down-Regulation; Doxycycline; Electrophysiology (science); Event; Exhibits; Exons; Fetal Proteins; Gastrointestinal tract structure; Gene Expression; Genes; Genetic; Genetic Transcription; Genomic Segment; Goals; Guide RNA; Heart; Human; Incidence; Individual; Interruption; Investigation; Knock-out; Life; Link; Mediating; Messenger RNA; MicroRNAs; Modeling; Molecular; Molecular Analysis; Mus; Muscular Dystrophies; Mutate; Myocardial dysfunction; Myotonic Dystrophy; Myotonic dystrophy type 1; Neuraxis; Nuclear RNA; Pathogenesis; Pathogenicity; Pathway interactions; Patients; Phenocopy; Phenotype; Physiological; Protein Isoforms; Protein Kinase C; Publishing; RNA; RNA Degradation; RNA Polymerase II; RNA Processing; RNA Splicing; RNA Transcription Inhibition; RNA-Binding Proteins; Regulation; Signal Pathway; Signal Transduction; Skeletal Muscle; Sodium Channel; Subcellular structure; System; Testing; Tetracyclines; Therapeutic; Tissue Sample; Tissues; Toxic effect; Trans-Activators; Transgenes; Transgenic Mice; Up-Regulation; Validation; Ventricular Dysfunction; Withdrawal; base; efficacy testing; endonuclease; expectation; heart function; in vivo; inducible gene expression; loss of function; mortality; mouse model; mutant; novel; novel therapeutic intervention; protein activation; skeletal muscle wasting; small molecule; sudden cardiac death; therapeutic evaluation; transcriptome; transcriptome sequencing; vector; voltage

Project Summary / Abstract Myotonic dystrophy (DM) is the most common cause of adult onset muscular dystrophy and the second most common cause of muscular dystrophy overall. At least 50% of individuals affected by DM type 1 (DM1) have cardiac involvement, primarily conduction abnormalities and life threatening arrhythmias. Cardiac involvement is the second leading cause of mortality in DM1 responsible for 25% of disease-related deaths. The pathogenic cause of DM1 is well established to be toxicity of the expanded CUG repeat- containing (CUGexp) RNA expressed from the expanded DMPK allele. The CUGexp RNA disrupts RNA processing, signaling pathways and microRNA regulation. However the specific molecular mechanisms by which expression of CUGexp RNA in heart tissue causes conduction abnormalities, arrhythmias and ventricular dysfunction are unknown. Therapeutic approaches applied to DM1 have focused on skeletal muscle and heart presents a separate set of issues with regard to both the details of disease mechanisms and therapeutic approaches. We developed a mouse model for tetracycline (tet)-inducible expression of CUGexp RNA specifically in cardiomyocytes. The tet-inducible transgene expresses 960 interrupted CUG repeats in the context of a human DMPK genomic segment containing exons 11-15. Expression of CUG960 RNA produces most of the cardiac conduction abnormalities and propensity for the arrhythmias that are likely to be responsible for cardiac sudden death in DM1. The mice also show robust splicing changes as observed in DM1 heart tissue. Importantly molecular and electrophysiological abnormalities are reversible upon shutting off expression of CUG960 RNA. In this project we will use the mouse model to identify and test hypotheses for the molecular basis for heart pathogenesis in DM1 and apply novel therapeutic approaches. The goal of the first aim is to use in vivo and ex vivo electrophysiological analyses in combination with detailed analyses of intracellular structure, transcriptome and signaling changes to identify the basis for the cardiac manifestations induced by CUG960 RNA. The key results will be tested in DM1 tissue samples for validation. The second aim is to use genetic rescue of the cardiac features to test hypothesized disease mechanisms, and with the expectation that multiple mechanisms contribute to pathogenesis, to determine the contributions of different mechanisms. The third aim is to apply approaches using deactivated Cas9 to target CUG960 RNA for transcriptional or post-transcriptional downregulation. Upon completion of this project we anticipate having an understanding of the molecular and physiological pathways linking CUGexp RNA to cardiac dysfunction and to have optimized a therapeutic approach to reverse DM1 cardiac features.

项目概要/摘要 强直性肌营养不良 (DM) 是成人发病的肌营养不良的最常见原因，也是第二位原因 总体上是肌营养不良症的最常见原因。至少 50% 的人受到 1 型糖尿病的影响 (DM1) 有心脏受累，主要是传导异常和危及生命的心律失常。 心脏受累是 DM1 死亡的第二大原因，占 25% 的疾病相关死亡 死亡人数。 DM1 的致病原因已明确是扩展的 CUG 重复序列的毒性。 含有从扩展的 DMPK 等位基因表达的 (CUGexp) RNA。 CUGexp RNA 破坏 RNA 加工、信号传导途径和 microRNA 调控。然而具体的分子机制 心脏组织中 CUGexp RNA 的表达会导致传导异常、心律失常和 心室功能障碍尚不清楚。适用于 DM1 的治疗方法主要集中在骨骼 肌肉和心脏在疾病机制的细节方面提出了一组单独的问题 和治疗方法。我们开发了四环素（tet）诱导表达的小鼠模型 CUGexp RNA 特异性存在于心肌细胞中。第960章 被人欺负 在包含外显子 11-15 的人类 DMPK 基因组片段中重复。 CUG960的表达 RNA 产生大部分心脏传导异常和心律失常倾向， 可能是导致 DM1 心源性猝死的原因。小鼠还表现出强大的剪接变化： 在 DM1 心脏组织中观察到。重要的是分子和电生理异常是可逆的 关闭 CUG960 RNA 的表达后。在本项目中我们将使用小鼠模型进行识别和测试 DM1 心脏发病机制的分子基础假设并应用新的治疗方法。 第一个目标是结合使用体内和离体电生理分析 详细分析细胞内结构、转录组和信号传导变化，以确定其基础 CUG960 RNA 诱导的心脏表现。主要结果将在 DM1 组织样本中进行测试 验证。第二个目标是利用心脏特征的基因拯救来测试假设的疾病 机制，并期望多种机制有助于发病机制，以确定 不同机制的贡献。第三个目标是应用使用停用 Cas9 的方法 靶向 CUG960 RNA 进行转录或转录后下调。该项目完成后 我们期望了解连接 CUGexp RNA 的分子和生理途径 心脏功能障碍并优化了逆转 DM1 心脏特征的治疗方法。