Deciphering mechanisms of myoblast fusion

破译成肌细胞融合机制

• 批准号: 10646466
• 负责人: Douglas Paul Millay
• 金额: $ 39.45万
• 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/10646466
• 关键词: Area; Biochemical; Biochemistry; Cell Membrane Permeability; 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; Permeability; Phase; Process; Proteins; Reaction; Regenerative Medicine; Role; Skeletal Muscle; Stress; System; Time; Transmembrane Domain; Work; 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; risk mitigation

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.

项目摘要/摘要 尽管肌细胞融合对于正常肌肉发育和生理学很重要，但相对较少的是 关于在成肌细胞融合反应期间直接重塑膜的分子已知。 阐明融合机制对于充分理解肌肉发育和识别新颖的机制至关重要 增加骨骼肌疾病的治疗策略。我们以前发现Myomaker（MyMK） 和Myomerger（MYMX）对于骨骼肌祖细胞的融合至关重要。而且，异位 这两种膜蛋白的表达诱导了原本非菌基因细胞（成纤维细胞）的融合。为了 第一次，这是用成肌细胞固定物建立基于细胞的重构系统，但是许多 关于这两种蛋白如何诱导融合的问题存在问题。我们最近发现Myomaker和 Myomerger驱动融合通过独特的细胞机制，通过分开其独立膜 重塑活动以明显影响融合过程。有理由认为膜变形 Myomaker和Myomerger的活动必须受到高度监管，否则它们可能有潜力 损害细胞完整性。确实，我们的初步实验探测了Myomaker的要求 营养不良疾病进展过程中的融合意外表明肌瘤的表达在营养不良中 肌纤维是有害的。在这个项目中，我们将：1）确定Myomaker的膜重新塑造活动 控制脂质混合（半分解）2）识别并审问半分解所需的其他因素3） 阐明肌分肌引发膜压力的机制驱动融合孔的形成。 此外，我们将在慢性肌肉疾病（肌肉营养不良）的背景下研究这些熔融。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的活性 和Myomaker，从而阐明了成肌细胞融合的机制。我们还将开发一个重组 用于肌细胞融合的蛋白质体系统。这些研究将提供对机制的独特见解 哺乳动物肌细胞融合。总体而言，这项工作有望为细胞开辟新的调查领域 肌肉的生物学，并积极影响利用融合改善再生医学的可能性。