Caveolae, mitochondria, and cardiac protection.

描述（由申请人提供）：心肌缺血/再灌注损伤是由线粒体功能障碍介导的，其中受损的线粒体在再灌注时利用氧气产生活性氧（ROS）而不是能量。活性氧具有破坏潜能。迄今为止发现的预防再灌注损伤最有益的实验干预措施是缺血预处理（IPC），它发生在心肌在致死性缺血再灌注之前暴露于短暂的缺血再灌注事件时。以前的工作已经评估了产生IPC的单一平行途径，利用导致心脏保护的膜受体激活的线性模型；然而，对于IPC的时间效率（即质膜与线粒体的快速耦合）和空间三维性（即许多途径的同时激活），还没有提出单一的、统一的机制。信号转导中的一个新观点（即，在具有动态电位的离散细胞室中组织的多蛋白复合物的存在）为IPC的时间/空间难题提供了一个可能的解决方案。两种膜结构蛋白caveolin-3 （Cav-3）和connexin43 （Cx43）存在于动态膜微环境中，为质膜富脂或间隙连接微域的多蛋白复合物提供空间组织。关于Cav-3和Cx43在预处理心肌中的相互作用和运输，以及这些蛋白的翻译后修饰对心脏保护的影响，我们知之甚少。我们的数据表明，小泡、小泡蛋白、Cx43和线粒体密切相关，并且这种关联可能在IPC中起作用。本研究旨在解决以下具体假设：1:IPC诱导的小泡蛋白和Cx43的翻译后修饰优化了小泡/线粒体相互作用，以减少缺血-再灌注损伤过程中产生的有害ROS。2：小泡蛋白和Cx43在ipc诱导的小泡与线粒体相互作用中是必不可少的。3 .小泡蛋白/Cx43的过表达可以增强小泡与线粒体的相互作用，从而模拟IPC。这项工作的长期目标是确定与心脏保护相关的新型信号机制，并确定在产生预处理表型中协调众多信号网络的关键分子。心脏病引起的伤害是致命的，会导致死亡。在心脏中发现的某些蛋白质控制着损伤程度。这项研究的目标是发现预防心脏病发作损伤的关键蛋白质，从而可以适当地设计药物。

DESCRIPTION (provided by applicant): Myocardial ischemia/reperfusion injury is mediated by mitochondrial dysfunction in which damaged mitochondria utilize oxygen at reperfusion for the generation of reactive oxygen species (ROS) rather than energy. ROS have destructive potential. The most beneficial experimental intervention thus far identified for preventing reperfusion injury is ischemic preconditioning (IPC), which occurs when the myocardium is exposed to brief ischemia-reperfusion events prior to lethal ischemia-reperfusion. Previous work has evaluated single parallel pathways that produce IPC utilizing a linear model of membrane receptor activation leading to cardiac protection; however, no single, unifying mechanism has been proposed for IPC to account for its temporal efficiency (i.e., rapid coupling of plasma membrane to mitochondria) and spatial 3-dimensionality (i.e., simultaneous activation of numerous pathways). An emerging idea in signal transduction (i.e., the existence of multi-protein complexes organized in discrete cellular compartments with dynamic potential) suggests a possible solution to this temporal/spatial conundrum of IPC. Two membrane structural proteins, caveolin-3 (Cav-3) and connexin43 (Cx43), exist in dynamic membrane microenvironments, and provide spatial organization to multi-protein complexes in lipid- rich or gap junctional microdomains of the plasma membrane. Little is known regarding Cav-3 and Cx43 interaction and trafficking in the preconditioned myocardium and the effect of post-translational modifications of these proteins on cardiac protection. Our data suggest a close association of caveolae, caveolin, Cx43, and mitochondria and a possible role for this association in IPC. The aims will address the following specific hypotheses: 1: The post-translational modification of caveolin and Cx43 induced by IPC optimizes caveolae/mitochondria interaction to reduce deleterious ROS generated during ischemic-reperfusion injury. 2: Caveolin and Cx43 are essential for IPC-induced interaction of caveolae and mitochondria. 3: Overexpression of caveolin/Cx43 can augment the interaction of caveolae and mitochondria to mimic IPC. The long-term goal of this work is to identify novel signaling mechanisms relevant to cardiac protection and determine the molecules critical in coordinating a multitude of signaling networks in producing a preconditioning phenotype. PUBLIC HEALTH RELEVANCE Injury form a heart attack is lethal and results in death. Certain proteins found in the heart control the degree of injury. It is the goal of this study to discover key proteins involved in protection against a heart attack injury so that drugs can be appropriately designed.