Mitochondrial inner membrane architecture in skeletal muscle pathophysiology

骨骼肌病理生理学中的线粒体内膜结构

• 批准号: 9979767
• 负责人: Bingwei Lu
• 金额: $ 34.43万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-17 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9979767
• 关键词: ATP phosphohydrolase; Aging; Amyotrophic Lateral Sclerosis; Animal Model; Animals; Apoptosis; Architecture; Binding; Biochemical; Bioenergetics; Biological; Biology; Buffers; C9ORF72; Calcium; Cell division; Cell physiology; Cells; Complex; Crista ampullaris; Cytosol; Degenerative Disorder; Denervation; Development; Dipeptides; Disease; Drosophila genus; Functional disorder; Genetic; Genetic Models; Genetic Screening; Goals; Health; Inner mitochondrial membrane; Lead; Link; Maintenance; Medicine; Membrane; Membrane Structure and Function; Metabolism; Mitochondria; Mitochondrial Encephalomyopathies; Mitochondrial Myopathies; Modeling; Molecular; Molecular Genetics; Molecular Target; Motion; Motor Neuron Disease; Muscle; Muscle Development; Muscle Mitochondria; Muscle function; Myopathy; Neuromuscular Junction; Notch Signaling Pathway; Numbness; Organelles; Outer Mitochondrial Membrane; PINK1 gene; Pathogenesis; Pathology; Pathway interactions; Peptide Hydrolases; Play; Process; Proteins; Proteomics; Quality Control; Regulation; Ribosomes; Role; Signal Pathway; Signal Transduction; Site; Skeletal Muscle; Structure; Synapses; System; Tissues; Toxic effect; Translations; age related; age related neurodegeneration; experimental study; fly; gene product; insight; mitochondrial dysfunction; muscle degeneration; muscle form; muscular structure; neuromuscular; normal aging; notch protein; novel; novel therapeutics; parkin gene/protein; proteostasis; sarcopenia; skeletal muscle wasting; stem cells; tool

Project Summary Muscle is a contractile tissue that generates forces and motions vital for animal survival. The molecular and cellular mechanisms governing its structural and functional integrity are not well understood. Selective dysfunction and degeneration of neuromuscular tissues have been observed in disease conditions featuring mitochondrial abnormality, emphasizing the particular importance of mitochondria to the functionality and integrity of muscle tissues. Mitochondria play important roles in cellular bioenergetics as well as other essential aspects of cellular physiology. The mitochondrial processes that are essential for the structural and functional integrity of skeletal muscle, and how these processes are regulated in health and disease are poorly defined. It is becoming increasingly clear that fundamental mechanisms underlying the development, function, and maintenance of skeletal muscle are conserved across metazoans. Thus genetic model organisms are poised to make significant contributions to our understanding of these mechanisms. In our previous studies, we have used Drosophila as a model to demonstrate the importance of Numb/Notch signaling and asymmetric progenitor cell division during muscle development, and PINK1/Parkin-directed mitochondrial quality control in skeletal muscle maintenance. We have also used the fly neuromuscular junction (NMJ) as a model to dissect synaptic mechanisms involved in age- related neurodegenerative diseases. In our most recent studies, we have found that protein quality control in the mitochondrial intermembrane space (IMS) is important for skeletal muscle function and maintenance. We found that dipeptide repeats (DPRs) derived from unconventional translation of the GGGGCC (G4C2) hexanucleotide repeat expansion in C9ORF72, the most common genetic cause of amyotrophic lateral sclerosis (ALS) called c9ALS, disrupt mitochondrial function by altering IMS proteostasis and inner membrane (IM) architecture. Our genetic modifier screens identified a number of signaling pathways in mitigating this ALS-related muscle pathology. The goal of this proposal is to use proteomic, molecular genetic, and cell biological tools to define the mechanism of action of the identified genetic pathways, in an effort to achieve a holistic view of the regulation and function of mitochondrial IM architecture in skeletal muscle function and maintenance. Two Specific Aims will help us reach this goal. In Aim 1, we will examine the molecular mechanisms of how c9ALS disease gene product disrupts muscle mitochondrial IMS/IM structure and function. Novel genetic tools will be used to perform ultrastructural studies and find the interactome of DPR within these structures. In Aim 2, we will delineate the cellular quality control mechanisms that maintain IMS/IM integrity by restraining the synthesis or promoting the metabolism of DPR. The role of these quality control mechanisms in maintaining mitochondrial and skeletal muscle structure and function during normal aging will also be examined. These studies will significantly advance our understanding of the role of mitochondria in maintaining skeletal muscle structure and function. Results from this study promise to inform the development of novel and rational muscle-targeting medicine for ALS and conditions such as sarcopenia.

项目概要 肌肉是一种收缩组织，可产生对动物生存至关重要的力和运动。分子和细胞 控制其结构和功能完整性的机制尚不清楚。选择性功能障碍和 在以线粒体为特征的疾病中观察到神经肌肉组织的退化 异常，强调线粒体对肌肉功能和完整性的特殊重要性 组织。线粒体在细胞生物能学以及细胞的其他重要方面发挥着重要作用 生理。对于骨骼的结构和功能完整性至关重要的线粒体过程 肌肉，以及这些过程在健康和疾病中如何调节，目前还不清楚。它正在成为 越来越清楚的是，骨骼发育、功能和维护的基本机制 肌肉在后生动物中是保守的。因此，遗传模型生物体有望做出重大贡献 有助于我们理解这些机制。在我们之前的研究中，我们使用果蝇作为 模型证明 Numb/Notch 信号传导和不对称祖细胞分裂过程中的重要性 肌肉发育，以及骨骼肌维护中 PINK1/Parkin 指导的线粒体质量控制。我们 还使用果蝇神经肌肉接头（NMJ）作为模型来剖析与年龄相关的突触机制 相关的神经退行性疾病。在我们最近的研究中，我们发现蛋白质质量控​​制 线粒体膜间隙（IMS）对于骨骼肌功能和维持很重要。我们发现 源自 GGGGCC (G4C2) 六核苷酸重复序列的非常规翻译的二肽重复序列 (DPR) C9ORF72 的扩增是肌萎缩侧索硬化症 (ALS) 称为 c9ALS 的最常见遗传原因， 通过改变 IMS 蛋白质稳态和内膜 (IM) 结构来破坏线粒体功能。我们的基因 修饰筛选确定了许多缓解这种 ALS 相关肌肉病理的信号通路。目标 该提案的目的是使用蛋白质组学、分子遗传学和细胞生物学工具来定义 已确定的遗传途径，以努力全面了解线粒体的调节和功能 骨骼肌功能和维护中的 IM 架构。两个具体目标将帮助我们实现这一目标。瞄准 1、我们将研究c9ALS疾病基因产物如何破坏肌肉线粒体的分子机制 IMS/IM结构和功能。新型遗传工具将用于进行超微结构研究并找到 这些结构中 DPR 的相互作用组。在目标 2 中，我们将描述细胞质量控制机制 通过抑制DPR的合成或促进代谢来维持IMS/IM的完整性。这些品质的作用 正常衰老过程中维持线粒体和骨骼肌结构和功能的控制机制将 也予以检查。这些研究将显着增进我们对线粒体在 维持骨骼肌的结构和功能。这项研究的结果有望为以下领域的发展提供信息 针对 ALS 和肌肉减少症等疾病的新型合理的肌肉靶向药物。