Pathogenesis of Emery-Dreifuss Muscular Dystrophy

金刚砂肌营养不良症的发病机制

• 批准号: 6611620
• 负责人: Howard J Worman
• 金额: $ 34.58万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-15 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6611620
• 关键词: autosomal dominant trait; cell differentiation; cell growth regulation; clinical research; fibroblasts; fluorescence microscopy; gene expression; gene mutation; genetic disorder; genetic regulation; genetically modified animals; human subject; laboratory mouse; lamins; lipodystrophy; membrane proteins; microarray technology; molecular pathology; muscular dystrophy; nuclear membrane; pathologic process; patient oriented research; protein localization; protein transport; sex linked trait; thymopoietin; tissue /cell culture

DESCRIPTION (provided by applicant): Emery-Dreifuss muscular dystrophy (EDMD) is characterized by region muscle contractures, slow progressive muscle wasting and cardiomyopathy with atrioventricular conduction block. Indistinguishable forms of EDMD are inherited in autosomal dominant and X-linked manners. Mutations in emerin, an integral protein of the nuclear envelope inner membrane, cause X-linked EDMD. Autosomal dominant EDMD is caused by mutations in the LMNA gene, which encodes the nuclear envelope intermediate filament proteins lamins A and C. It is not known how mutations in nuclear envelope proteins cause muscular dystrophy. We hypothesize that mutations in these chromatin-associated proteins cause changes in the expression of genes responsible for muscle cell differentiation or survival. Our goal is to test this hypothesis using a combination of studies in transfected cells, patients' cells and tissues and animals models. In the first specific aim, we will use fluorescence microscopy and photobleaching methods to investigate how lamin A and C mutants from patients with autosomal dominant EDMD influence the mobility of emerin in the inner nuclear membrane. We will determine if mutant lamins A and C cause emerin to "escape" from the inner nuclear membrane into the continuous endoplasmic reticulum. As patients with X-linked EDMD do not have emerin in the inner nuclear membrane, this finding would demonstrate a connection between the X-linked and autosomal dominant forms of the disease. In the second aim, we will use microarrays to compare gene expression in cells from patients with autosomal dominant EDMD to X-linked EDMD and Dunnigan-type partial lipodystrophy, a disease caused by mutations in different regions of lamins A and C. This will establish if emerin and lamin mutations responsible for EDMD alter expression of the same genes. We will also use microarrays to determine gene expression profiles in muscles from lamin A/C "knockout" mice that develop muscular dystrophy and compare the results to what is known about pathologic alterations in gene expression in Duchenne muscular dystrophy. The results will be confirmed in tissues from human subjects with EDMD. In Aim 3, we will generate transgenic mice expressing human lamin A mutants and determine if they develop pathological abnormalities of EDMD and similar gene expression changes. This work will help establish how abnormalities in the nuclear envelope cause muscular dystrophy.

描述（由申请方提供）：Emery-Dreifuss肌营养不良症（EDMD）的特征为局部肌肉挛缩、缓慢进行性肌肉萎缩和伴有房室传导阻滞的心肌病。 EDMD的不可区分形式以常染色体显性和X连锁方式遗传。 Emerin是核膜内膜的一种完整蛋白，其突变导致X连锁EDMD。 常染色体显性EDMD是由LMNA基因突变引起的，LMNA基因编码核膜中间丝蛋白核纤层蛋白A和C。目前尚不清楚核膜蛋白的突变如何导致肌营养不良症。 我们推测，这些染色质相关蛋白的突变导致负责肌细胞分化或存活的基因表达的变化。 我们的目标是使用转染细胞、患者细胞和组织以及动物模型中的研究组合来测试这一假设。 在第一个具体的目标，我们将使用荧光显微镜和光漂白的方法来研究如何核纤层蛋白A和C突变体的常染色体显性遗传EDMD患者的影响的流动性Emerin的内核膜。 我们将确定是否突变核纤层蛋白A和C导致emerin“逃逸”从内核膜进入连续内质网。 由于X连锁EDMD患者的内核膜中没有emerin，这一发现将证明X连锁和常染色体显性形式的疾病之间的联系。 在第二个目标中，我们将使用微阵列比较常染色体显性EDMD患者与X连锁EDMD和Dunnigan型部分脂肪营养不良（一种由核纤层蛋白A和C不同区域突变引起的疾病）细胞中的基因表达。 这将确定EDMD的emerin和lamin突变是否改变了相同基因的表达。 我们还将使用微阵列来确定来自核纤层蛋白A/C“敲除”小鼠的肌肉中的基因表达谱，并将结果与已知的杜氏肌营养不良症中基因表达的病理改变进行比较。 将在EDMD人类受试者的组织中证实结果。在目标3中，我们将产生表达人核纤层蛋白A突变体的转基因小鼠，并确定它们是否发生EDMD的病理异常和类似的基因表达变化。 这项工作将有助于确定核被膜异常如何导致肌肉萎缩症。