Deciphering mechanisms of myoblast fusion

破译成肌细胞融合机制

• 批准号: 10442423
• 负责人: Douglas Paul Millay
• 金额: $ 39.92万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10442423
• 关键词: Area; Biochemical; Biochemistry; Cell membrane; Cells; Cellular biology; Chronic; Chronic Disease; Data; Disease; Disease Progression; Ectopic Expression; Event; Exercise; Fibroblasts; Generations; Genetic; Goals; Integral Membrane Protein; Investigation; Knowledge; Lipids; Mammalian Cell; Membrane; Membrane Fusion; Membrane Lipids; Membrane Proteins; Molecular; Muscle; Muscle Cells; Muscle Development; Muscular Dystrophies; Myoblasts; Myopathy; Natural regeneration; Pathogenesis; Pathologic; Pathology; Phase; Process; Proteins; Reaction; Regenerative Medicine; Risk; Role; Skeletal Muscle; Stress; System; Time; Transmembrane Domain; Work; base; design; experimental study; improved; indexing; insight; mdx mouse; mouse model; muscle physiology; muscle regeneration; myogenesis; novel; novel strategies; novel therapeutic intervention; progenitor; protein function; proteoliposomes; reconstitution

Project Summary/Abstract Despite the importance of myoblast fusion for normal muscle development and physiology, relatively little is known about the molecules that directly function to remodel membranes during the myoblast fusion reaction. Elucidation of fusion mechanisms is critical to fully understand muscle development and to identify novel therapeutic strategies to augment skeletal muscle disease. We previously discovered that myomaker (Mymk) and myomerger (Mymx) are essential for the fusion of skeletal muscle progenitors. Moreover, ectopic expression of these two membrane proteins induces fusion of otherwise non-fusogenic cells (fibroblasts). For the first time, this establishes a cell-based reconstitution system with myoblast fusogens, however many questions exist as to how these two proteins induce fusion. We have recently found that myomaker and myomerger drive fusion through a unique cellular mechanism, by dividing their independent membrane remodeling activities to distinctly impact the fusion process. It stands to reason that the membrane-remodeling activities of myomaker and myomerger must be highly regulated or they could have the potential to compromise cellular integrity. Indeed, our preliminary experiments probing the requirement of myomaker for fusion during dystrophic disease progression unexpectedly revealed that myomaker expression in dystrophic myofibers is deleterious. In this project we will: 1) determine the membrane-remodeling activities of myomaker that control lipid mixing (hemifusion) 2) identify and interrogate the additional factors required for hemifusion 3) elucidate the mechanisms by which myomerger elicits membrane stresses that drive fusion pore formation. Additionally, we will study these fusogens in the context of chronic muscle disease (muscular dystrophy). We will use cell biology, biochemistry, and genetic mouse models to study and define the activities of myomaker and myomaker, thereby elucidating the mechanisms of myoblast fusion. We will also develop a reconstituted proteoliposome system for myoblast fusion. These studies will provide unique insight into the mechanisms of mammalian myoblast fusion. Overall, this work promises to open up a new area of investigation into the cell biology of muscle and positively impact the possibility to harness fusion to improve regenerative medicine.

项目概要/摘要 尽管成肌细胞融合对于正常肌肉发育和生理学很重要，但相对较少 已知在成肌细胞融合反应期间直接发挥重塑膜功能的分子。 阐明融合机制对于充分了解肌肉发育和识别新的融合机制至关重要 增强骨骼肌疾病的治疗策略。我们之前发现 myomaker (Mymk) 和 myomerger (Mymx) 对于骨骼肌祖细胞的融合至关重要。此外，异位 这两种膜蛋白的表达诱导其他非融合细胞（成纤维细胞）的融合。为了 这是第一次用成肌细胞融合剂建立了基于细胞的重建系统，但许多 关于这两种蛋白质如何诱导融合存在疑问。我们最近发现 myomaker 和 myomerger 通过独特的细胞机制驱动融合，通过分裂它们的独立膜 重塑活动明显影响融合过程。按理说，膜重塑 myomaker 和 myomerger 的活动必须受到严格监管，否则它们可能有可能 损害细胞完整性。事实上，我们的初步实验探讨了 myomaker 的需求 营养不良性疾病进展期间的融合意外地揭示了营养不良性疾病中肌细胞标记的表达 肌纤维是有害的。在这个项目中，我们将：1）确定 myomaker 的膜重塑活动 控制脂质混合（半融合）2) 识别并询问半融合所需的其他因素 3) 阐明 myomerger 引发膜应力以驱动融合孔形成的机制。 此外，我们将在慢性肌肉疾病（肌营养不良）的背景下研究这些融合剂。我们 将使用细胞生物学、生物化学和遗传小鼠模型来研究和定义 myomaker 的活动 和 myomaker，从而阐明成肌细胞融合的机制。我们还将开发重组的 用于成肌细胞融合的蛋白脂质体系统。这些研究将提供对机制的独特见解。 哺乳动物成肌细胞融合。总的来说，这项工作有望开辟细胞研究的新领域 肌肉生物学并对利用融合改善再生医学的可能性产生积极影响。