Project 2

项目2

• 批准号: 10473542
• 负责人: PRADEEP P.A. MAMMEN
• 金额: $ 55.05万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-15 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10473542
• 关键词: 17 year old; ATAC-seq; Adult; Age; Age-Years; Applications Grants; Atrophic; Attention; Attenuated; Autophagocytosis; Autopsy; Becker Muscular Dystrophy; Birth; CRISPR/Cas technology; Cardiac; Cardiac Myocytes; Cardiomyopathies; Childhood; DNA Sequence Alteration; Data; Data Set; Development; Disease; Duchenne muscular dystrophy; Dystrophin; Gene Expression; Genes; Genome; Goals; Growth; Heart; Heart Hypertrophy; Hot Spot; Human; Image; Immunohistochemistry; Innovative Therapy; Investigation; Laboratories; Left; Left Ventricular Mass; Life; Link; Longevity; Magnetic Resonance Imaging; Measures; Metabolism; Mission; Modality; Molecular; Molecular Profiling; Morbidity - disease rate; Muscle; Muscular Atrophy; Mutation; Neuromuscular Diseases; Pathologic; Patients; Phenotype; Proteins; Public Health; Pyruvate; Quantitative Reverse Transcriptase PCR; Sampling; Signal Pathway; Site; Structure; Symptoms; Techniques; Testing; Therapeutic; Time; United States National Institutes of Health; Ventricular; Weight; Western Blotting; age group; cardiac magnetic resonance imaging; clinical phenotype; coronary fibrosis; exome sequencing; genome editing; heart function; heart metabolism; imaging modality; implantation; improved; induced pluripotent stem cell derived cardiomyocytes; innovation; left ventricular assist device; magnetic resonance imaging biomarker; mdx mouse; molecular phenotype; mortality; mouse model; muscular dystrophy mouse model; new therapeutic target; next generation sequencing; novel therapeutics; sex; skeletal muscle wasting; therapeutic genome editing; transcriptome sequencing

Project Summary/Abstract for Project 2 Duchenne muscular dystrophy (DMD) is a recessive X-linked neuromuscular disorder resulting from mutations in the dystrophin gene, which ultimately produces progressive muscle wasting and atrophy. Importantly, DMD patients develop cardiac fibrosis and a decrease in cardiac function leading to advanced cardiomyopathy, which is currently the major contributor to mortality in DMD patients. The mission of the UT Southwestern Wellstone Center is to develop CRISPR/Cas9 genome editing as a therapeutic modality for DMD patients; however, issues related to DMD-associated cardiomyopathy will continue to persist. Project 1 proposes to use genome editing to target the 12 “hot spots” within the dystrophin gene making a truncated dystrophin protein and converting a DMD patient into a Becker muscular dystrophy (BMD) patient. Thus, the overall goal of Project 2 is to develop novel therapies to attenuate the morbidity and mortality associated with DMD- associated cardiomyopathy. Significant strides have been made in treating non-DMD cardiomyopathy; however, there are no definitive therapies to effectively induce long term reverse cardiac remodeling and improve overall cardiac function within DMD patients. Our group has undertaken a cardiac MRI study demonstrating that adult DMD patients have very low left ventricular (LV) mass as well as low LV concentricity as compared to age-, sex-, and weight-matched control patients. Once a DMD patient develops symptoms related to advanced cardiomyopathy, the DMD heart starts to dilate and enlarge resembling the structure of advanced dilated non-ischemic cardiomyopathy. These observations raise the question whether the development of pathological cardiac hypertrophy is the primary mechanism underlying DMD-associated cardiomyopathy. Does the observed low LV mass and concentricity arise due to prolonged immobility or are independent of a DMD patient’s ability to ambulate? Data from the Mammen Laboratory indicates that mdx mice, a murine model of DMD, have altered cardiac metabolism and also have low cardiac mass due to a decrease in proliferative gene expression during the first week of life. Therefore, the central hypothesis of Project 2 is that low LV mass and concentricity in DMD-associated cardiomyopathy leads to progressive cardiomyopathy independent of a DMD patient’s ability to ambulate. To test our central hypothesis, we will pursue the following three specific aims: Specific Aim 1: Characterize the clinical and molecular phenotypes in ambulatory and non-ambulatory DMD patients as a function of patient age. Specific Aim 2: Define the cardiac phenotype in BMD-associated cardiomyopathy as a function of patient age and site of the genetic mutation. Specific Aim 3: Determine the molecular phenotypes of human DMD and BMD cardiomyocytes.

项目 2 的项目摘要/摘要 杜氏肌营养不良症 (DMD) 是一种由突变引起的隐性 X 连锁神经肌肉疾病 存在于肌营养不良蛋白基因中，最终导致进行性肌肉萎缩和萎缩。重要的是，DMD 患者出现心脏纤维化和心功能下降，导致晚期心肌病， 目前，这是导致 DMD 患者死亡的主要原因。 UT西南大学的使命 Wellstone 中心将开发 CRISPR/Cas9 基因组编辑作为 DMD 患者的治疗方式； 然而，与 DMD 相关的心肌病相关的问题将继续存在。项目1拟采用 基因组编辑以肌营养不良蛋白基因内的 12 个“热点”为目标，形成截短的肌营养不良蛋白 将 DMD 患者转变为贝克尔肌营养不良症 (BMD) 患者。因此，总体目标是 项目 2 是开发新疗法以降低与 DMD 相关的发病率和死亡率 相关的心肌病。非DMD心肌病的治疗已取得重大进展； 然而，没有明确的疗法可以有效诱导长期逆转心脏重塑 改善 DMD 患者的整体心脏功能。我们小组进行了心脏 MRI 研究 证明成年 DMD 患者的左心室 (LV) 质量非常低，左心室同心度也较低 与年龄、性别和体重匹配的对照患者相比。一旦 DMD 患者出现症状 与晚期心肌病相关，DMD 心脏开始扩张并增大，类似于心脏的结构 晚期扩张型非缺血性心肌病。这些观察结果提出了一个问题： 病理性心脏肥大的发展是 DMD 相关的主要机制 心肌病。观察到的低 LV 质量和同心度是否是由于长时间不动而产生的，还是 与 DMD 患者的行走能力无关吗？ Mammen 实验室的数据表明 mdx 小鼠是一种 DMD 小鼠模型，其心脏代谢发生了改变，并且心脏质量也较低，这是由于 生命第一周增殖基因表达减少。因此，中心假设 项目 2 是 DMD 相关心肌病的低左心室质量和同心度导致进行性进展 心肌病与 DMD 患者的行走能力无关。为了检验我们的中心假设，我们将 追求以下三个具体目标： 具体目标 1：表征临床和分子表型 在动态和非动态 DMD 患者中，作为患者年龄的函数。具体目标 2：定义 BMD 相关心肌病的心脏表型与患者年龄和遗传部位有关 突变。具体目标 3：确定人 DMD 和 BMD 心肌细胞的分子表型。