MG53-Mediated Membrane Repair in Muscle Physiology and Disease

MG53 介导的肌肉生理学和疾病中的膜修复

• 批准号: 8545523
• 负责人: Jianjie Ma
• 金额: $ 32.83万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-16 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8545523
• 关键词: Acute; Affect; Animal Model; Binding; Biochemical; Biochemical Markers; Biological Process; Caveolae; Cell membrane; Cell physiology; Cells; Cholesterol; DYSF gene; Data; Defect; Degenerative Disorder; Disease; Docking; Familial generalized lipodystrophy; Functional disorder; Gene Mutation; Goals; Human; Injury; Knock-out; Life; Link; Lipodystrophy; Mediating; Membrane; Modeling; Molecular; Mus; Muscle; Muscle Cells; Muscle Fibers; Muscular Dystrophies; Mutation; Natural regeneration; Paper; Physiological; Physiology; Polymerase; Prevention; Process; Proteins; Publishing; RNA Interference; Recovery; Regenerative Medicine; Regulation; Research Design; Role; Signal Transduction; Site; Skeletal Muscle; Structure; TRIM Family; Testing; Therapeutic Agents; Transcript; Transgenic Organisms; Translating; base; caveolin-3; cell injury; cellular imaging; genetic manipulation; human disease; improved; in vivo; injured; membrane assembly; muscular dystrophy mouse model; novel; novel therapeutic intervention; overexpression; reconstruction; release factor; repaired; research and development; research study; response; restoration; sensor

DESCRIPTION (provided by applicant): Repair of acute damage to the plasma membrane is an important aspect of normal cellular physiology and disruption of this process can result in pathophysiology in a number of human diseases including muscular dystrophy. We recently discovered that MG53, a muscle-specific TRIM-family protein, is an essential component of the membrane repair machinery. While our published data define the sensor function for MG53 in cell membrane repair, the molecular mechanisms underlying the nucleation process remain to be defined. Since MG53 can discriminate between intact and injured membrane, a membrane-delimited signal would likely be involved in tethering of MG53 to the injured site. In pilot studie, we found that PTRF is an obligatory factor for MG53-mediated nucleation of the membrane repair response, for cells lacking endogenous expression of PTRF show defective membrane resealing. While RNAi- silencing of PTRF leads to defective membrane repair in muscle fibers, overexpression of PTRF can rescue this defect in dysferlin-/- muscle but not in mg53-/- muscle, suggesting that the functional role of PTRF in membrane repair likely requires the presence of MG53. While many studies have explored the function of PTRF in regulating caveolae structure of the plasma membrane, our data present a new biological function for PTRF as an anchoring molecule for MG53 for initiation of the cell membrane repair response. Since mutations in PTRF have been identified in human disorders with lipodystrophy and muscular dystrophy, conditions that often involve compromised membrane integrity or resealing capacity, targeting the functional interaction between MG53 and PTRF, or restoration of the disrupted MG53-PTRF interaction in the diseased states, may represent an attractive avenue for treatment or prevention of degenerative diseases involving compromised membrane repair. The long-term goal of this project is to understand the cellular and molecular mechanism for membrane repair in muscle physiology and diseases. Specifically, we will focus on testing the hypothesis that "PTRF acts as a docking protein for MG53-mediated cell membrane repair, and restoration of membrane integrity in muscular dystrophy can be achieved through enhancement of MG53/PTRF function at the interface of membrane injury". Our proposed studies will focus on defining the molecular mechanism underlying the functional interaction between MG53 and PTRF for initiation of the cell membrane repair response in skeletal muscle (Aim 1); and exploring the physiological role of MG53 and PTRF in muscle physiology and diseases and test if enhancement of PTRF-MG53 function can improve membrane integrity in muscular dystrophy (Aim 2). Through tailored-expression of MG53 and PTRF and the use of biochemical markers, live cell imaging, ex vivo and in vivo animal model studies, the designed experiments will provide key proof-of-principle data for targeting MG53/PTRF-mediated cell membrane repair in treatment of muscular dystrophy.

描述（由申请人提供）：质膜急性损伤的修复是正常细胞生理学的一个重要方面，该过程的破坏可能导致包括肌营养不良在内的许多人类疾病的病理生理学。我们最近发现 MG53，一种肌肉特异性 TRIM 家族蛋白，是膜修复机制的重要组成部分。虽然我们发表的数据定义了 MG53 在细胞膜修复中的传感器功能，但成核过程背后的分子机制仍有待定义。由于 MG53 可以区分完整的膜和受损的膜，膜分隔信号可能参与 MG53 与受损部位的束缚。在初步研究中，我们发现 PTRF 是 MG53 介导的膜修复反应成核的必要因素，因为缺乏 PTRF 内源表达的细胞表现出有缺陷的膜重新密封。虽然 PTRF 的 RNAi 沉默会导致肌纤维中的膜修复缺陷，但 PTRF 的过度表达可以挽救 Dysferlin-/- 肌肉中的这种缺陷，但不能挽救 mg53-/- 肌肉中的这种缺陷，这表明 PTRF 在膜修复中的功能作用可能需要MG53的存在。虽然许多研究探索了 PTRF 在调节质膜小窝结构中的功能，但我们的数据提出了 PTRF 作为 MG53 锚定分子启动细胞膜修复反应的新生物学功能。由于在患有脂肪营养不良和肌营养不良的人类疾病中已经鉴定出 PTRF 突变，这些疾病通常涉及膜完整性或重新密封能力受损，目标是 MG53 和 PTRF 之间的功能相互作用，或在疾病状态下恢复被破坏的 MG53-PTRF 相互作用，可能是治疗或预防涉及膜修复受损的退行性疾病的一种有吸引力的途径。该项目的长期目标是了解肌肉生理学和疾病中膜修复的细胞和分子机制。具体来说，我们将重点检验以下假设：“PTRF充当MG53介导的细胞膜修复的对接蛋白，并且可以通过增强膜损伤界面处的MG53/PTRF功能来恢复肌营养不良症中的膜完整性” 。我们提出的研究将侧重于定义 MG53 和 PTRF 之间功能相互作用的分子机制，以启动骨骼肌细胞膜修复反应（目标 1）；探索 MG53 和 PTRF 在肌肉生理学和疾病中的生理作用，并测试增强 PTRF-MG53 功能是否可以改善肌营养不良症中的膜完整性（目标 2）。通过MG53和PTRF的定制表达以及生化标记物、活细胞成像、离体和体内动物模型研究的使用，设计的实验将为靶向MG53/PTRF介导的细胞膜修复提供关键的原理验证数据用于治疗肌营养不良症。