RNA Toxicity and Cardiac Pathology

项目总结： 强直性肌营养不良症(DM1)是成人和儿童中最常见的肌营养不良症，是一种常染色体 由糖尿病蛋白激酶(DMPK)基因扩大的CTG重复导致的显性遗传疾病 与突变RNA的核滞留和随后的RNA毒性有关。心脏是人体的主要器官之一 在DM1中受影响。高达75%的成年DM1患者存在心脏传导问题，猝死 由于心律失常是DM1最常见的死亡原因之一。不幸的是，其发病机制 DM1的心脏表现还不是很清楚。DM1中心脏病的临床焦点一直在 心律失常和传导异常。值得注意的是，dm1中心脏缺陷的病理已经有了历史。 与间质纤维化、心脏传导组织脂肪渗出和纤维化有关。我们报道了 第一个可诱导的小鼠RNA毒性和心脏传导缺陷模型，并展示了其潜在的 通过沉默有毒RNA的产生，使DM1表型可逆性。最近使用的是DM200鼠标模型， 我们首次在DM1中展示了反义寡核苷酸(ASO)治疗心脏病的潜力。 我们还发现了与心脏中RNA毒性相关的纤维化改变的证据。在过去的十年里， 新的心脏MRI研究的出现导致了对心脏疾病的了解的证据和兴趣的增加 DM1纤维化及其在DM1临床病理中的作用。我们建议使用DM200小鼠模型作为 用于在临床前模型中开发和研究这些想法和概念并尝试理解 心脏纤维成脂变化的细胞和分子驱动因素。我们将在三个月内完成这项工作 目标独立但相辅相成。首先，我们将开发和评估心脏mri作为rna的生物标志物。 对心脏有毒性。第二，我们将确定心脏PDGFRA+Ve细胞在纤维/脂肪形成中的作用。 心脏对RNA毒性的病理反应。第三，基于转化生长因子β增加的初步证据 ，我们将表征转化生长因子β在心脏核糖核酸毒性中的作用，并研究其治疗反应 针对纤维化和转化生长因子β(包括针对转化生长因子β2和转化生长因子β3的异构体特异性抗体)的治疗。 重要的是，我们将在治疗试验中验证CMR协议和参数：a)下一代 针对有毒核糖核酸的ASO和b)针对纤维化和转化生长因子β的治疗。我们的目标是了解 与DM1中的RNA毒性相关的心脏病理驱动因素，并评估和建立潜在的 心脏核磁共振作为监测疾病进展和治疗反应的工具的应用。

Project Summary: Myotonic dystrophy (DM1), the most common form of muscular dystrophy in adults and children, is an autosomal dominant genetic disorder caused by an expanded CTG repeat in the DM protein kinase (DMPK) gene that leads to nuclear retention of the mutant RNA and subsequent RNA toxicity. The heart is one of the primary organs affected in DM1. Cardiac conduction problems are present in up to 75% of adult DM1 cases, and sudden death due to cardiac arrhythmias is one of the most common causes of death in DM1. Unfortunately, the pathogenesis of cardiac manifestations in DM1 is not well understood. Clinical focus for cardiac disease in DM1 has been on arrhythmias and conduction abnormalities. Of note, the pathology of cardiac defects in DM1 has been historically associated with interstitial fibrosis, and fatty infiltration and fibrosis of cardiac conduction tissues. We reported the first inducible mouse model of RNA toxicity and cardiac conduction defects and demonstrated the potential for reversibility of DM1 phenotypes by silencing toxic RNA production. Recently using the DM200 mouse model, we showed for the first time, the potential for antisense oligonucleotides (ASOs) to treat cardiac disease in DM1. We also found evidence for fibrotic changes associated with RNA toxicity in the heart. In the past decade, the advent of new cardiac MRI studies has led to evidence of and an increased interest in understanding cardiac fibrosis in DM1 and its role in the clinical pathology of DM1. We propose to use the DM200 mouse model as a tool for developing and investigating these ideas and concepts in a pre-clinical model and to try to understand the cellular and molecular drivers of fibro-adipogenic changes in the heart. We will do this through three independent but complementary aims. First, we will develop and evaluate cardiac MRI as a biomarker for RNA toxicity in the heart. Second, we will determine the role of cardiac PDGFRA+ve cells in fibro/adipogenic pathologic responses to RNA toxicity in the heart. Third, based on preliminary evidence of increased TGFβ in the heart, we will characterize the role of TGFβs in RNA toxicity in the heart, and study the therapeutic response to therapies targeting fibrosis and TGFβ (including isoform specific antibodies against TGFβ2 and TGFβ3). Importantly, we will validate the CMR protocols and parameters in therapeutic trials using: a) next generation ASOs that target the toxic RNA and b) the therapies targeting fibrosis and TGFβs. Our goals are to understand the drivers of cardiac pathology associated with RNA toxicity in DM1, and to evaluate and establish the potential utility of cardiac MRI as a tool to monitor disease progression and response to therapy.