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: 10441283
• 负责人: Bingwei Lu
• 金额: $ 34.09万
• 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/10441283
• 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; Parkin; 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; 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.

项目摘要 肌肉是一种收缩组织，产生对动物存活至关重要的力和运动。分子和细胞 尚不清楚管理其结构和功能完整性的机制。选择性功能障碍和 在具有线粒体的疾病状况中，已经观察到神经肌肉组织的变性 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基本方面中起重要作用 生理。线粒体过程对于骨骼的结构和功能完整性至关重要 肌肉以及这些过程在健康和疾病中的调节方式的定义很差。它正在变成 越来越清楚的是，骨骼发育，功能和维护的基本机制 肌肉是在整个后生动物中保守的。因此，遗传模型生物有望产生重要 对我们对这些机制的理解的贡献。在我们以前的研究中，我们使用果蝇作为 模型以证明麻木/缺口信号传导和非对称祖细胞分裂的重要性 肌肉发育和骨骼肌维护中的PINK1/PARKIN指导的线粒体质量控制。我们 还使用蝇神经肌肉连接（NMJ）作为模型，以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 线粒体膜间空间（IMS）对于骨骼肌功能和维护很重要。我们发现 GGGGCC（G4C2）六核苷酸重复的非常规翻译得出的二肽重复序列（DPRS） C9ORF72的扩张，这是肌萎缩性侧索硬化症（ALS）的最常见遗传原因，称为C9ALS， 通过更改IMS蛋白质和内膜（IM）体系结构来破坏线粒体功能。我们的遗传 修饰符屏幕在减轻与ALS相关的肌肉病理学时鉴定了许多信号通路。目标 该建议的是使用蛋白质组学，分子遗传和细胞生物学工具来定义 确定的遗传途径是为了实现线粒体调节和功能的整体视图 IM骨骼肌功能和维护中的体系结构。两个具体的目标将有助于我们实现这一目标。目标 1，我们将研究C9als病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。在AIM 2中，我们将描绘出细胞质量控制机制 通过限制合成或促进DPR的代谢来维持IMS/IM的完整性。这些质量的作用 在正常衰老期间维持线粒体和骨骼肌结构以及功能的控制机制将 也可以检查。这些研究将大大提高我们对线粒体在 维持骨骼肌结构和功能。这项研究的结果承诺将为发展提供信息 针对ALS和疾病（例如肌肉减少症）的新颖和理性肌肉靶向医学。