Nuclear mechanics and mechanotransduction in muscular laminopathies

描述(申请人提供)：细胞核是真核细胞的显著特征，由核膜与周围的细胞质隔开。核膜蛋白Lamin A/C和Emerin的突变会导致Emery-Dreifuss肌营养不良症、四肢带状肌营养不良症、家族性部分脂肪营养不良症和其他各种称为椎板病的疾病。潜在的疾病机制尚不清楚，部分原因是核膜蛋白的功能尚未完全确定。我的长期目标是了解这些无处不在表达的蛋白质突变导致这种组织特有表型的分子机制(S)。这一建议的中心主题是肌肉特异性表型产生于核膜功能的特定异常，从结构功能受损到转录调控异常，导致适应性和保护性通路受损。我的具体目标是：1.表征与Emery-Dreifuss肌营养不良症相关的突变对细胞核稳定性和细胞对机械应变的敏感性的具体影响。利用最近建立的技术，我将检验这一假设，即Emery-Dreifuss肌营养不良症患者的皮肤成纤维细胞特定地损害了核的稳定性和机械敏感基因的异常调节，导致在应变下细胞活力下降。来自家族性部分脂营养不良患者和健康对照组的细胞将分别作为非特异性缺陷和正常核膜功能的对照。2.确定这些突变对核力学和基因调控的肌肉特异性影响。为了验证细胞核稳定性和机械转导中的组织特异性缺陷导致Emery-Dreifuss肌营养不良症肌肉表型的假设，我将比较来自Emery-Dreifuss肌营养不良症小鼠模型的肌肉细胞的核力学、应变诱导的基因调控和应变下的细胞活力，与来自相同动物的成纤维细胞和来自野生型小鼠的细胞进行比较。研究这些突变的特定细胞缺陷将有助于我们更好地理解核膜的正常和组织特异性功能，并导致对Emery-Dreifuss肌营养不良和其他椎板病(如四肢带状肌营养不良)的分子机制的新见解，可能为这些疾病的治疗提供新的靶点。

DESCRIPTION (provided by applicant): The nucleus is the distinguishing feature of eukaryotic cells and is separated from the surrounding cytoplasm by the nuclear envelope. Mutations in the nuclear envelope proteins lamin A/C and emerin cause Emery- Dreifuss muscular dystrophy, limb-girdle muscular dystrophy, familial partial lipodystrophy, and a variety of other diseases referred to as laminopathies. The underlying disease mechanism is unclear, in part because the function of the nuclear envelope proteins is incompletely defined. My long term goal is to understand the molecular mechanism(s) by which mutations in these ubiquitously expressed proteins can lead to such tissue-specific phenotypes. The central theme of this proposal is that muscle-specific phenotypes arise from specific abnormalities in nuclear envelope function, ranging from impaired structural function to abnormal transcriptional regulation, resulting in impaired adaptive and protective pathways. My specific aims are to: 1. Characterize the specific effects of mutations linked to Emery-Dreifuss muscular dystrophy on nuclear stability and cellular sensitivity to mechanical strain. Using recently established techniques, I will test the hypothesis that skin fibroblasts from Emery-Dreifuss muscular dystrophy patients have specifically impaired nuclear stability and abnormal regulation of mechanosensitive genes, resulting in decreased cell viability under strain. Cells from familial partial lipodystrophy patients and healthy control subjects will serve as controls for non-specific defects and normal nuclear envelope function, respectively. 2. Identify the muscle-specific effects of these mutations on nuclear mechanics and gene regulation. To test the hypothesis that tissue-specific defects in nuclear stability and mechanotransduction contribute to the muscular phenotype in Emery-Dreifuss muscular dystrophy, I will compare nuclear mechanics, strain- induced gene regulation, and cell viability under strain in muscle cells derived from mouse models of Emery- Dreifuss muscular dystrophy with fibroblasts from the same animals and with cells from wild-type littermates. Studying the specific cellular defects of these mutations will help to improve our understanding of normal and tissue-specific functions of the nuclear envelope and lead to new insights into the molecular mechanisms responsible for Emery-Dreifuss muscular dystrophy and other laminopathies such as limb-girdle muscular dystrophy, potentially providing new targets for the treatment of these diseases.