Role of The Mitok ATP Channel in Digitalis Signaling in the Heart

心肌梗死继发缺血性损伤是世界范围内死亡的主要原因。洋地黄，最古老的和 最具特色的心力衰竭药物，保护缺血-再灌注损伤，它通过 激活线粒体ATP敏感性钾通道(MitoKATp)。这个项目的中心假设是 哇巴因激活的信号被传递到线粒体，导致mitoKATp的开放增加 保护心脏的活性氧簇(ROS)的产生和存活蛋白的激活。我们的 长期目标是揭示通过以下途径调节洋地黄诱导的心脏保护的机制 激活Na，K-ATPase/mitoKATp途径。在此期间，我们将重点研究 从肌膜Na，K-ATPase到线粒体的信号传递。目标1将检验假设 洋地黄可引起功能活跃的腔隙微域(信号体)的形成，这些微域与 线粒体外膜，导致mitoKATp开放和线粒体通透性抑制 过渡。目的2将研究信号小体循环和信号小体功能的持续性。目标3 将使用电子显微镜和免疫金标记法研究信号体的组装和运输。 目的4将在兔心脏模型中研究洋地黄保护和信号转导的关键方面，其 心功能和洋地黄的药理作用更接近于人类心脏。各种实验性的 将使用各种方法。信号小体将从灌流的心脏中提纯并进行功能测试 从未经处理的心脏分离的线粒体的活性。这些生理学研究的结果将是 由对灌流心脏梗死面积的平行研究支持。纯化的信号体也将受到 进行生化和结构分析，以确定它们的组成和来源。

Cardiac infarction followed by ischemic injury is a major cause of death worldwide. Digitalis, the oldest and best characterized heart failure drug, protects against ischemia-reperfusion injury, and it does so through activation of the mitochondrial ATP-sensitive K+ channel (mitoKATp). The central hypothesis of this project is that ouabain-activated signals are relayed to mitochondria, resulting in mitoKATp opening, increased production of reactive oxygen species (ROS) and activation of survival kinases that protect the heart. Our long-term goal is to uncover the mechanisms that regulate digitalis-induced cardioprotection through activation of the Na,K-ATPase / mitoKATp pathway. During this period, we will focus on the mechanism of signal transmission from the sarcolemmal Na,K-ATPase to mitochondria. Aim 1 will test the hypothesis that digitalis causes formation of functionally active caveolar microdomains (signalosomes) that interact with the mitochondrial outer membrane, leading to mitoKATp opening and inhibition of the mitochondrial permeability transition. Aim 2 will investigate signalosome recycling and the persistence of signalosome function. Aim 3 will investigate signalosome assembly and transport using electron microscopy and immunogold labeling. Aim 4 will investigate key aspects of digitalis protection and signaling in the rabbit heart model, whose cardiac function and digitalis pharmacology are closer to those in human heart. A variety of experimental approaches will be used. Signalosomes will be purified from perfused hearts and tested for functional activity on mitochondria isolated from untreated hearts. Results of these physiological studies will be supported by parallel studies of infarct size on perfused hearts. Purified signalosomes will also be subjected to biochemical and structural analyses to characterize their composition and origin.