Investigating mechanisms of vertebrate myoblast fusion using zebrafish as a model

以斑马鱼为模型研究脊椎动物成肌细胞融合机制

• 批准号: 10213657
• 负责人: Elizabeth H Chen
• 金额: $ 34.98万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10213657
• 关键词: Actins; Animals; Biochemical; Biological; Biology; Cell Adhesion Molecules; Cell Therapy; Cell membrane; Cells; Cytoskeleton; Defect; Degenerative Disorder; Development; Disease; Drosophila genus; Electron Microscopy; Embryo; Event; Exhibits; F-Actin; Future; Genes; Genetic; Health; Human; Image; Invaded; Knowledge; Life; Location; Maintenance; Mass Spectrum Analysis; Mechanics; Mediating; Membrane; Membrane Fusion; Modeling; Molecular; Mus; Muscle; Muscle Development; Muscle Fibers; Muscle satellite cell; Myoblasts; Myopathy; Natural regeneration; Orthologous Gene; Patients; Process; Property; Proteins; Resolution; Site; Skeletal Muscle; System; Testing; Therapeutic; Vertebrates; Zebrafish; congenital myopathy; in vivo; in vivo Model; insight; molecular marker; mouse model; muscle physiology; muscle regeneration; mutant; novel; polymerization; satellite cell; sensor; therapeutic development

PROJECT SUMMARY Myoblast fusion, the process in which mononucleate myoblasts fuse to form multinucleate, contractile muscle fibers, is essential for skeletal muscle development, maintenance and regeneration. Insights into the molecular and cellular mechanisms of myoblast fusion to date have mainly come from studies of a genetic system, the fruit fly Drosophila. Studies in Drosophila have uncovered a handful of evolutionarily conserved regulators of myoblast fusion, ranging from cell adhesion molecules to actin polymerization regulators to mechanical sensors. More importantly, Drosophila studies have identified a novel cellular mechanism underlying myoblast fusion at the site of fusion – an attacking cell aggressively invades its fusion partner using actin-propelled membrane protrusions, whereas the receiving cell increases mechanical tension to resist the invasion, leading to cell membrane juxtaposition, fusogen engagement and plasma membrane fusion. Besides evolutionarily conserved fusion-promoting proteins, recent studies in zebrafish and mouse have identified a pair of vertebrate-specific fusogenic proteins, Myomaker and Myomixer (also known as Myomerger and Minion). However, how and where these proteins facilitate myoblast fusion is largely unknown. Compared to Drosophila studies, a major issue that hinders the study of the mechanisms underlying vertebrate myoblast fusion is the lack of knowledge of the precise sites of fusion. While myoblast fusion appears to occur at undefined location(s) along a broad cell-cell contact zone in cultured mammalian myoblasts, the sites of myoblast fusion in an intact animal remain completely unknown. Thus, it is imperative to identify the sites of fusion in vivo and provide a cellular framework upon which future studies can be built. Zebrafish is an excellent vertebrate model to study myoblast fusion in vivo, due to the large number of small and transparent zebrafish embryos and their rapid ex-utero development. In this proposal, we will use zebrafish as an in vivo model to define the sites of myoblast fusion in an intact vertebrate animal with molecular markers. In addition, we will study the localization and potential interaction between the fusogens, Myomaker and Myomixer. Furthermore, we will explore the interaction between the fusogens and the cell adhesion molecules and the actin cytoskeleton. Insights from the proposed studies will have a broad impact on understanding the fundamental principles of muscle development and regeneration, and ultimately may be exploited for the development of therapeutic strategies to optimize satellite cell-mediated muscle regeneration in patients with muscle degenerative diseases.

项目摘要 肌细胞融合，单核细胞肌细胞融合形成多核，收缩肌肉的过程 纤维对于骨骼肌发育，维护和再生至关重要。对分子的见解 迄今为止，成肌细胞融合的细胞机制主要来自对遗传系统的研究 飞果蝇。果蝇的研究发现了一些进化的调节剂 从细胞粘附分子到肌动蛋白聚合调节剂到机械传感器的成肌细胞融合。 更重要的是，果蝇研究已经确定了在成肌融合的基础的新型细胞机制 Fusion的位置 - 攻击细胞使用肌动蛋白膜的膜积极入侵其融合伴侣 突起，而接收电池会增加机械张力以抵抗侵袭，从而导致细胞 膜并置，融合原和质膜融合。除了进化保守 融合促蛋白，斑马鱼和小鼠的最新研究鉴定了一对脊椎动物特异性 融合蛋白，肌瘤制造剂和肌反应蛋白（也称为Myomerger and Minion）。但是，如何以及在哪里 这些蛋白质最喜欢的成肌细胞融合在很大程度上是未知的。与果蝇研究相比 阻碍研究脊椎动物肌细胞融合的机制的研究是缺乏对 精确的融合位置。而肌细胞融合似乎沿着宽细胞细胞发生在不确定的位置 培养的哺乳动物肌细胞中的接触区，完整动物中肌细胞融合的位点保持完全 未知。这是必须识别体内融合的位点，并提供一个细胞框架 可以建立未来的研究。斑马鱼是一个出色的脊椎动物模型，用于研究体内成肌细胞融合 大量的小且透明的斑马鱼胚胎及其快速的前发育。在此提案中， 我们将使用斑马鱼作为体内模型来定义与完整脊椎动物中的成肌细胞融合的位点 分子标记。此外，我们将研究融合剂之间的定位和潜在相互作用， Myomaker和Myomixer。此外，我们将探索熔融与细胞之间的相互作用 粘附分子和肌动蛋白细胞骨架。拟议研究的见解将对 了解肌肉发育和再生的基本原理，最终可能是 开发用于优化卫星细胞介导的肌肉再生的治疗策略的开发 肌肉退行性疾病的患者。