MG53 mediated myocardial repair for ischemic heart disease

描述(由申请人提供)： 摘要在美国，缺血性心脏病仍然是最大的死亡原因，每年占死亡人数的三分之一以上。急性缺血性损伤和慢性心肌病会导致心脏组织的永久性丢失，最终导致心力衰竭。开发新的治疗方法，可以直接针对缺血/再灌注(IR)损伤中心肌细胞死亡的原因，将具有广泛的翻译潜力。我们最近的发现表明，MG53是TRIM家族(TRIM72)中一个新的肌肉特异性成员，对于肌肉损伤的修复是必不可少的，也为心血管疾病的治疗提供了一个靶点。这一应用重点是验证我们的假设，即MG53是缺血再灌注损伤后心肌修复的必需分子，细胞外重组MG53可能促进心肌修复和预防缺血性心脏病。在特定的目标1，我们将研究氧化应激、缺血或急性损伤条件下MG53介导的心肌修复的机制。本提案的目的2将利用野生型和MG53-/-动物模型确定重组MG53对心肌缺血再灌注损伤的保护作用。具体地说，我们将确定在再灌注前后应用MG53蛋白是否可以预防或减轻缺血再灌注所致的心肌损伤。这些实验的实现可能为靶向MG53治疗缺血性心脏病的可行性提供必要的原则证明研究。 公共卫生相关性： 项目简介在大多数西方国家，缺血性心脏病是最常见的死亡原因。开发新的治疗方法，可以直接针对缺血/再灌注(IR)损伤中心肌细胞死亡的原因，将具有广泛的翻译潜力。在再生医学中，有一条很有潜力成为治疗靶点的途径是单个细胞在损伤后修复质膜的过程。我们最近发现MG53是TRIM蛋白家族(TRIM72)中的一个新的肌肉特异性成员，它在骨骼肌的动态膜修复过程中起着重要作用(1-3)。然而，MG53在心肌保护中的作用仍不清楚。在这一应用中，我们将进行实验，以探讨MG53在心肌缺血/再灌注损伤后修复中的作用。首先，我们将使用野生型和MG53基因敲除小鼠模型来研究在氧化应激、缺血或急性损伤条件下MG53介导的心肌细胞膜损伤修复的机制。我们还将通过对野生型和MG53基因敲除小鼠的心肌表现进行综合评估，包括超声心动图、免疫组织化学和共聚焦显微镜，来评估重组MG53蛋白对心肌缺血再灌注损伤的保护作用。这一结果将为为心血管疾病患者开发有效的基于蛋白质的心脏修复疗法的原则验证研究提供新的见解。

DESCRIPTION (provided by applicant): Abstract Ischemic heart disease remains as the single largest leading causes of death in the U.S.A. accounting for more than 1 in 3 deaths per annum. Acute ischemic injury and chronic cardiomyopathy lead to permanent loss of cardiac tissue and ultimately heart failure. Developing novel therapeutic approaches that can directly target the causes of cardiomyocyte death during Ischemia/Reperfusion (IR) injury will have broad translational potential. Our recent findings suggest that MG53, a novel muscle-specific member of the TRIM family of proteins (TRIM72), is essential for repair of muscle damage, and also provide a therapeutic target for treatment of cardiovascular diseases. This application focuses on testing our hypothesis that "MG53 is an essential molecule for myocardial repair following ischemia-reperfusion injury, and extracellular recombinant MG53 may promote myocardial repair and prevent ischemic heart disease". In specific aim 1, we will examine the mechanism underlying MG53-mediated myocardial repair under conditions of oxidative-stress, ischemia or acute injury with isolated cardiomyocytes from neonatal mice. Aim 2 of this proposal will establish the efficacy of recombinant MG53 in protection against IR injury to the heart muscle using the wild type and mg53-/- animal models. Specifically, we will determine if the application of MG53 protein prior to or after reperfusion can prevent or attenuate ischemia-reperfusion induced myocardial injury. Fulfillment of the proposed experiments may provide the essential proof-of-principle studies on the feasibility of targeting MG53 in treatment of ischemic heart disease. PUBLIC HEALTH RELEVANCE: Project Narrative Ischemic heart disease is the most common cause of death in most Western countries. Developing novel therapeutic approaches that can directly target the causes of cardiomyocyte death during Ischemia/reperfusion (IR) injury will have broad translational potential. One pathway with great potential as a therapeutic target in regenerative medicine is the process by which individual cells repair their plasma membrane following injury. We recently found that MG53 is a novel, muscle-specific member of the TRIM family of proteins (TRIM72), which contributes to the dynamic membrane repair process in skeletal muscle (1-3). However, the role of MG53 in myocardial protection remains unknown. In this application, we will conduct experiments to investigate the impacts of MG53 in myocardial repair following Ischemia/reperfusion injury. Initially, we will use both wild type and MG53 knockout mice models to investigate the mechanism underlying MG53-mediated repair of membrane damage to cardiomyocytes under conditions of oxidative-stress, ischemia or acute injury. We will also assess the efficacy of recombinant MG53 protein in protection against IR injury to the heart muscle using comprehensive evaluation of myocardial performance, including echocardiography, immunohistochemistry and confocal microscopy with the wild type and MG53 knockout mice. The results will provide novel insights into proof-of-principle studies to develop effective protein-based therapies for cardiac repair in patients with cardiovascular diseases.