Molecular examination of mitochondrial calcium control

摘要 心脏中的Ca 2+升高可以作为心脏能量输出增加的信号。 通过直接增加电子传递链的活性来增强线粒体， 选择模板。然而，与此同时， 急性心肌梗死后发生损伤可引起心肌细胞坏死， 通过线粒体通透性转换孔（PTP）的开放的凋亡性死亡。 线粒体Ca 2+单向转运体（MCU）复合物通过线粒体内的Ca 2+转运体转运Ca 2+。 线粒体基质中，它可以影响能量的产生， 急性缺血性损伤时PTP开放。因此，MCU的复杂性和许多 最近描述的构成它的基因可能是新的治疗靶点， 以减少心肌细胞死亡或改变心脏代谢为目标的药物设计 性能构成MCU的基因最近才被发现，因此， 关于线粒体Ca 2+的遗传相关性，该领域仍处于起步阶段 调节与体内心脏生理和病理生理。在这里，我们建议使用 缺乏这些线粒体Ca 2+处理的关键分子调节因子的小鼠， 解码并区分基线时生理和病理Ca 2+信号 和疾病。我们的首要目标是研究线粒体Ca 2+如何流入， 外排调节心脏的生命、死亡和代谢。然而，没有一个心脏 我们领域的实验室具有基本的专业知识，既可以表征复杂的 线粒体Ca 2+处理的生物物理学，同时采用必要的 小鼠遗传学和细胞生物学，以真正实现该项目的既定目标。因此，我们认为， 我们要求更新我们的合作双PI提案，该提案将是50/50的努力 在Molkentin和Bers实验室之间， 遗传学和心脏生理学与创新的评估线粒体和 细胞内Ca ~（2+）显像和PTP活性。我们的目标是：目标1： 检查MCUb和MCU复合物如何调节肌细胞[Ca]Mito以影响 目的2：阐明NCLX对心肌缺血再灌注损伤的调节作用， 功能，PTP开放和IR损伤后细胞死亡，目的3：确定替代/ 缓慢的[Ca]Mito流入效应器，其在心脏中独立于MCU运行。两个PI 在与多个共享出版物和联合出版物合作方面有着良好的记录 赠款。因此，它们代表了两种不同实验室技能的理想融合， 需要真正了解线粒体Ca 2+调节及其对心脏的影响， 生理学和疾病反应。

Abstract Ca2+ elevations in the heart can serve as a signal for augmented energy output from the mitochondria by directly increasing the activity of the electron transport chain and select dehydrogenases. However, at the same time sustained elevations in Ca2+ that occurs acutely after myocardial infarction injury can cause cardiomyocyte necrotic and apoptotic death through opening of the mitochondrial permeability transition pore (PTP). The mitochondrial Ca2+ uniporter (MCU) complex imports Ca2+ across the inner membrane into the mitochondrial matrix where it can affect both energy production and PTP opening during acute ischemic injury. Hence the MCU complex and many of the more recently described genes that constitute it could be novel therapeutic targets for drug design with the goal of reducing cardiomyocyte death or altering cardiac metabolic performance. The genes that comprise the MCU were only recently identified hence the field is still in its infancy with respect to genetically correlating mitochondrial Ca2+ regulation with cardiac physiology and pathophysiology in vivo. Here we propose to use mice lacking some of these key molecular regulators of mitochondrial Ca2+ handling to decode and differentiate between physiological and pathological Ca2+ signals at baseline and with disease. Our overarching goal is to examine how mitochondrial Ca2+ influx and efflux regulates cardiac life, death and metabolism. However, no single cardiac laboratory in our field has the underlying expertise to both characterize the complex biophysics of mitochondrial Ca2+ handling and at the same time employ the necessary mouse genetics and cell biology to truly achieve the stated goals of this project. Hence, we are requesting to renew our collaborative dual-PI proposal that will be 50/50 effort between the Molkentin and Bers laboratory, to wed the very best in mouse molecular genetics and cardiac physiology with innovative assessment of mitochondrial and intracellular Ca2+ imagining and PTP activity, respectively. Our Aims will be: Aim 1: Examine how MCUb and the MCU complex regulates myocyte [Ca]Mito to affect metabolism and PTP opening with IR injury, Aim 2: Elucidate NCLX regulation in cardiac function, PTP opening and cell death after IR injury, and Aim 3: Identify the alternate / slow [Ca]Mito influx effectors that operate independent of MCU in the heart. The 2 PIs have a strong track record of working together with multiple shared publications and joint grants. Hence, they represent an ideal melding of 2 divergent laboratory skill sets that are needed to truly understand mitochondrial Ca2+ regulation and its effect on cardiac physiology and disease responsiveness.