Nuclear mechanics and mechanotransduction in muscular laminopathies

肌肉核纤层蛋白病的核力学和机械转导

基本信息

批准号：
8842171
负责人：
Jan Lammerding
金额：
$ 39.65万
依托单位：
CORNELL UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-01-01 至 2016-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8842171
关键词：
Actins Address Adrenergic Agonists Adult Affect Animals Biological Assay Biopsy Cardiac Cardiac Myocytes Cell Death Cell Nucleus Cell physiology Cells Clinical Treatment Congenital Heart Defects Cytoplasm Cytoplasmic Organelle Cytoskeletal Proteins Cytoskeleton Data Defect Development Dilated Cardiomyopathy Disease Drosophila genus Drosophila melanogaster Emery-Dreifuss Muscular Dystrophy Event Familial partial lipodystrophy Fibroblasts Gene Expression Regulation Genes Genetic Goals Health Heart Contractilities Heart Diseases Heart Rate Human In Vitro Inherited Iowa Lamin Type A Lamins Larva Lead Leg Limb-Girdle Muscular Dystrophies Link Measures Mechanical Stress Mechanics Modeling Molecular Muscle Muscle Cells Muscular Dystrophies Mutate Mutation Myocardium Myopathy Normal tissue morphology Nuclear Nuclear Envelope Nuclear Lamin Nuclear Structure Nuclear Translocation Outcome Pathway interactions Patients Phenotype Play Progressive Disease Property Proteins Reporter Reporting Rupture Serum Response Factor Severities Signal Pathway Signal Transduction Skeletal Muscle Stress Structure Testing Tissues Universities arm design disease phenotype env Gene Products factor A fly human disease improved in vivo induced pluripotent stem cell insight lamin C loris mouse model mutant myocardin novel prevent protein function research study response transcription factor wasting

项目摘要

DESCRIPTION (provided by applicant): More than one-third of all cases of dilated cardiomyopathy are caused by inherited mutations, with 5% to 10% of these mutations being linked to the LMNA gene, which encodes the nuclear envelope proteins lamin A and C. Importantly, mutations in the LMNA gene are also responsible for a broad spectrum of other diseases, including Emery-Dreifuss muscular dystrophy, limb-girdle muscular dystrophy and familial partial lipodystrophy. Despite recent advances, the mechanism(s) responsible for the often muscle-specific defects caused by different lamin mutations remains elusive. The central hypothesis of this proposal is that lamin mutations can cause skeletal and cardiac muscle disease through two, possibly overlapping mechanisms: (i) loss of structural function of lamins A and C, leading to rupture of the more fragile nucleus in mechanically stressed tissues; (ii) disturbing (mechanosensitive) signaling pathways that results in impaired function of muscle cells. Specific LMNA mutations may differentially affect these distinct aspects of lamin function, resulting in a broad spectrum of disease phenotypes. My long term goal is to understand the molecular mechanism(s) by which mutations in the nearly ubiquitously expressed lamins can lead to muscle-specific phenotypes and to explore to what extent impaired nuclear structure and altered cellular sensitivity to mechanical stress contribute to the muscle-specific phenotypes. In the first aim, we will test the hypothesis that altered nuclear mechanics result in increased nuclear rupture in mechanically stressed tissue. By using a genetic reporter assay that can detect even transiently compromised nuclear envelope integrity in cardiac myocytes in three mouse models of muscular laminopathies, we can directly assess whether mutations in nuclear envelope proteins cause increased rates of nuclear rupture in cardiac tissue. In the second aim, we will determine the relationship between impaired nuclear mechanics and the severity of muscular phenotypes in laminopathies. Using drosophila melanogaster models expressing a panel of lamin mutations with variable muscle involvement, we will relate effects of the mutations on the mechanical properties of nuclei in intact muscle tissue in drosophila larvae with the severity of muscle defects in adult flies. In the third aim, we will investigate the interplay between lamin mutations responsible for dilated cardiomyopathy and a specific signaling pathway, myocardin-related transcription factor A (MRTF-A). We will explore the mechanism(s) responsible for the impaired nuclear translocation of MRTF-A in lamin A/C-deficient and mutant cells we recently discovered and assess the functional consequences of impaired MRTF-A signaling on cellular function. Studying the effects of lamin mutations on nuclear structure and cellular signaling will improve our understanding of normal and tissue-specific functions of these proteins and lead to new insights into the molecular mechanisms responsible for dilated cardiomyopathy, Emery-Dreifuss muscular dystrophy and other laminopathies, potentially providing new targets for the treatment of these diseases.

描述（由申请人提供）：超过三分之一的扩张型心肌病病例是由遗传性突变引起的，其中 5% 至 10% 的突变与 LMNA 基因相关，该基因编码核膜蛋白核纤层蛋白 A 和 C重要的是，LMNA 基因突变还导致多种其他疾病，包括 Emery-Dreifuss 肌营养不良症、肢带型肌营养不良症和家族性部分性肌营养不良症。脂肪营养不良。尽管最近取得了进展，但由不同核纤层蛋白突变引起的肌肉特异性缺陷的机制仍然难以捉摸。该提议的中心假设是核纤层蛋白突变可以通过两种可能重叠的机制引起骨骼和心肌疾病：（i）核纤层蛋白A和C的结构功能丧失，导致机械应力组织中更脆弱的细胞核破裂； (ii) 干扰（机械敏感）信号通路，导致肌肉细胞功能受损。特定的 LMNA 突变可能会对核纤层蛋白功能的这些不同方面产生不同的影响，从而导致广泛的疾病表型。我的长期目标是了解几乎普遍表达的核纤层蛋白中的突变可导致肌肉特异性表型的分子机制，并探索受损的核结构和改变的细胞对机械应力的敏感性在多大程度上导致肌肉-特定的表型。在第一个目标中，我们将检验这样的假设：核力学的改变会导致机械应力组织中核破裂的增加。通过使用基因报告分析，可以检测三种肌纤维病小鼠模型中心肌细胞中短暂受损的核膜完整性，我们可以直接评估核膜蛋白的突变是否会导致心脏组织核破裂率增加。在第二个目标中，我们将确定受损的核力学与核纤层蛋白病中肌肉表型的严重程度之间的关系。使用表达一组具有不同肌肉参与的核纤层蛋白突变的果蝇模型，我们将把突变对果蝇幼虫完整肌肉组织中细胞核机械特性的影响与成年果蝇肌肉缺陷的严重程度联系起来。在第三个目标中，我们将研究导致扩张型心肌病的核纤层蛋白突变与特定信号通路心肌素相关转录因子 A (MRTF-A) 之间的相互作用。我们将探索我们最近发现的核纤层蛋白 A/C 缺陷和突变细胞中 MRTF-A 核转位受损的机制，并评估 MRTF-A 信号传导受损对细胞功能的功能影响。研究核纤层蛋白突变对核结构和细胞信号传导的影响将提高我们对这些蛋白质的正常和组织特异性功能的理解，并可能对导致扩张型心肌病、埃默里-德莱福斯肌营养不良和其他核纤层蛋白病的分子机制产生新的见解。为这些疾病的治疗提供新的靶点。