Identifying the RNA Splicing and Gene Expression Changes that cause Congenital Myotonic Dystrophy

摘要 先天性强直性肌营养不良是强直性肌营养不良最严重的形式，导致 虚弱，呼吸困难，出生时喂养困难。在童年时期，孩子们经常 有智力障碍、疲劳、行为担忧和虚弱。重要的是，许多人 这些症状不同于那些患有强直性肌营养不良的成年人。在患有肌强直的成年人中 营养不良是一种有毒的RNA重复扩张，导致全球对RNA剪接的错误调控。它不是 明确先天性强直性肌营养不良是否存在相同的机制。这样的信息是 至关重要，因为治疗强直性肌营养不良的新疗法针对的是这个问题。这份提案是专门设计的 目的探讨先天性强直性肌营养不良的发病机制。调查人员将评估 肌肉样本中RNA剪接和基因表达的变化，然后验证这些变化 通过招募100名15岁以下先天性心脏病儿童的DM1细胞模型的变化 强直性肌营养不良。儿童将接受身体机能和体能测试 基线访问时的认知和肌肉的细针抽吸将被收集。儿童 患有先天性强直性肌营养不良的患者将在12个月后返回进行临床评估。这些 儿童将与30例组织病理学正常的肌肉活检进行比较。 在目标1中，我们将初步评估RNA剪接的变化，并将这些变化与 临床结果衡量标准，以确定哪些特定的转录本与 症状。关键的RNA剪接事件将被评估为临床功能的预测因子 为期12个月的访问。在目标2中，我们还将评估在类似的 方式，这在强直性肌营养不良症中还没有做过。曾经的关键基因表达和RNA 剪接签名已经确定，AIM 3将在DM1细胞模型中对它们进行评估 MBNL1封存和其他剪接调节因子在特定剪接事件中的作用。这 是DM1的关键致病机制之一。在这个项目完成时，我们将确定 并进行了初步实验以了解这些事件的作用 在疾病的机制中。通过更好地了解先天性肌强直的发病机制 营养不良，我们允许这些儿童接受强直性肌强直的疾病修改治疗 营养不良，以及为药物开发确定新的治疗靶点。

Abstract Congenital myotonic dystrophy, the most severe form of myotonic dystrophy, causes weakness, breathing problems, and feeding problems at birth. During childhood, children often have intellectual impairment, fatigue, behavioral concerns and weakness. Importantly, many of the symptoms are distinct from those adults with myotonic dystrophy. In adults with myotonic dystrophy, a toxic RNA repeat expansion leads to global misregulation of RNA splicing. It is not clear if the same mechanism is involved in congenital myotonic dystrophy. Such information is critical since new treatments for myotonic dystrophy target this issue. This proposal is designed to evaluate the pathogenesis of congenital myotonic dystrophy. The investigators will evaluate changes in RNA splicing and gene expression in muscle samples and then validate these changes in a DM1 cell model by enrolling 100 children below the age of 15 with congenital myotonic dystrophy. Children will be evaluated with measures of physical function and cognition at the baseline visit and a fine needle aspirate of the muscle will be collected. Children with congenital myotonic dystrophy will return for a clinical evaluation at 12 months. These children will be compared to 30 histopathologically normal muscle biopsies. In Aim 1, we will initially evaluate changes in RNA splicing and correlate these with the clinical outcome measures to identify those specific transcripts that most directly correlate with symptoms. Key RNA splicing events will be evaluated as predictors of clinical function at the 12-month visit. In Aim 2, we will also evaluate secondary gene expression changes in a similar manner, which has not been done in myotonic dystrophy. Once key gene expression and RNA splicing signatures have been identified, Aim 3 will evaluate them in a DM1 cell model to assess the role of MBNL1 sequestration and other splicing regulators for a particular splice event. This is a key pathogenic mechanism in DM1. At the completion of this project, we will have identified key biomarkers and performed preliminary experiments to understand the role of these events in the mechanism of disease. By better understanding the pathogenesis of congenital myotonic dystrophy, we allow these children access to disease modifying therapies in myotonic dystrophy, as well as identify new therapeutic targets for drug development.