Mechanisms of resealing and rebuilding in muscle repair

肌肉修复对于维持正常的肌肉功能是必不可少的。肌肉损伤，无论是由于创伤还是 过度使用，与肌膜完整性的丧失有关。重新密封被破坏的肌膜是一种 肌肉修复所需的关键步骤。肌营养不良亚型是由基因突变引起的 削弱肌膜，使其容易破裂，并需要强大的修复机制。其他 肌营养不良亚型源于基因驱动的修复蛋白缺陷，而这些基因 紊乱说明了有助于膜稳定性和膜的蛋白质和机制。 修理。对受损肌肉和营养不良肌肉的研究发现了肌肉修复的阶段，以及 立即重新封存阶段，然后是重建阶段。肌膜再密封是通过 在肌膜断裂部位形成帽状结构。我们和其他人已经证明，这个上限是 富含膜联蛋白，尤其是膜联蛋白A6，一种肌肉营养不良症的修饰物。显性负值 膜联蛋白A6通过对膜联蛋白组装的影响，破坏修复帽的形成，导致 膜渗漏过多，修复效果不佳。修复帽由一环“肩部”蛋白质支撑 这有助于加强再密封过程，这些蛋白包括dyferlin、MG53和EHD蛋白。 在肌肉细胞质内，紧邻肌膜破坏的是一个活跃的区域，它富含 肌动蛋白和脱铁蛋白相关蛋白Fer1L5。此外，肌动蛋白聚合是正常再密封所必需的。 最近的研究强调了肌肉重建的作用，肌肉重建是在肌膜重新密封之后进行的，包括 肌节集合。通过这个研究项目，我们先前展示了费林蛋白的作用 和膜联蛋白通过优化高分辨率实时可视化进行肌膜再密封。我们也 开发了新的遗传工具来阐明这些蛋白质在膜事件中的相互作用。我们现在 建议研究再密封蛋白在它们与Aim 1中肌动蛋白富集区相互作用中的作用。 目的2，我们将研究在肌肉修复过程中再封闭和重建的分子和时间重叠。在……里面 目的3，我们将使用生物活性脱细胞基质来定义和探索细胞外基质的作用。 在健康和疾病中调节细胞对肌肉修复的作用的膜联蛋白。这项工作的成果 将发现新的蛋白质-细胞相互作用，以指导促进肌肉修复的药理学。

Muscle repair is essential to maintain normal muscle function. Muscle injury, whether due to trauma or overuse, is associated with a loss of muscle membrane integrity. Resealing the disrupted sarcolemma is a critical step needed for muscle repair. Subtypes of muscular dystrophy arise from genetic mutations that weaken the sarcolemma, rendering it prone to disruption and requiring robust repair mechanisms. Other subtypes of muscular dystrophy arise from genetically-driven deficits in repair proteins, and these genetic disorders have illustrated proteins and mechanisms that contribute to membrane stability and membrane repair. Studies of injured muscle and dystrophic muscle have uncovered phases of muscle repair, an immediate resealing phase followed by a rebuilding phase. Sarcolemmal resealing occurs through the formation of a cap at the site of muscle membrane disruption. We and others have shown that this cap is enriched for annexin proteins, especially annexin A6, a modifier of muscular dystrophy. Dominant negative annexin A6 disrupts the formation of the repair cap, through its effects on annexin assembly, leading to excessive membrane leak and ineffective repair. The repair cap is supported by a ring of “shoulder” proteins that serve to reinforce the resealing process, and these proteins include dysferlin, MG53, and EHD proteins. Within the muscle cytoplasm immediately abutting sarcolemmal disruption is an active area that is enriched for actin and the dysferlin related protein, Fer1L5. Moreover, actin polymerization is required for normal resealing. Recent work highlighted the role of muscle rebuilding, which follows sarcolemma resealing and includes sarcomere assembly. Through this research program, we previously demonstrated the role of ferlin proteins and annexins in sarcolemmal resealing by optimizing high-resolution real-time visualization. We also developed novel genetic tools to elucidate the interaction of these proteins in membrane events. We now propose to investigate the role of resealing proteins in their interaction with the actin-rich region in Aim 1. In Aim 2, we will examine the molecular and temporal overlap of resealing and rebuilding during muscle repair. In Aim 3, we will use biologically active decellularized matrices to define and probe the role of extracellular annexins in regulating cellular contributions to muscle repair in health and disease. The outcomes of this work will discover new protein-cellular interactions to guide the pharmacology of promoting muscle repair.