Inhibition of MCUR1-MCU mediated mitochondrial Ca2+ uptake prevents I/R injury

抑制 MCUR1-MCU 介导的线粒体 Ca2 摄取可预防 I/R 损伤

基本信息

批准号：
8694610
负责人：
MADESH MUNISWAMY
金额：
$ 38.94万
依托单位：
TEMPLE UNIV OF THE COMMONWEALTH
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-04-01 至 2018-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8694610
关键词：
ATP Hydrolysis ATP Synthesis Pathway Address Animal Model Autophagocytosis Biochemical Biochemistry Bioenergetics Biological Models Buffers Cardiac Cardiac Myocytes Cardiovascular Diseases Cell Death Cell Membrane Permeability Cell Survival Cell membrane Cells Cellular biology Charge Complex Coupling Disease Down-Regulation Heart Homeostasis Hypoxia Image Inner mitochondrial membrane Ion Channel Ions Ischemia Learning Maintenance Mediating Membrane Potentials Membrane Transport Proteins Mica Mitochondria Mitochondrial Matrix Mitochondrial Membrane Protein Molecular Mus Mutagenesis Nature Outcome Oxidation-Reduction Oxidative Stress Pathologic Processes Pathway interactions Pattern Phenotype Phosphorylation Physiological Physiological Processes Play Production Proteins RNA Interference Reaction Reactive Oxygen Species Regulation Reperfusion Injury Reperfusion Therapy Rest Role Shapes Side Signal Transduction Staging Study models Technology Therapeutic Intervention Tissues Transcriptional Regulation Translating base calcium uniporter cell type driving force in vivo in vivo Model mitochondrial dysfunction mitochondrial membrane mitochondrial permeability transition pore oxidation prevent public health relevance small hairpin RNA spatiotemporal uptake

项目摘要

DESCRIPTION (provided by applicant): Mitochondrial bioenergetics is crucial for cell survival and death. The bioenergetic maintenance primarily depends on the integrity of mitochondrial membranes. The impermeable nature of the mitochondrial inner membrane sets the stage for redox reactions to generate ATP. Mitochondria also participate in cytosolic Ca2+ phenotype via rapid Ca2+ buffering. There are two sides to the effects of Ca2+ on mitochondrial function. Under physiological conditions, Ca2+ is beneficial for mitochondrial function to stimulate oxidation-phosphorylation and ATP synthesis. It is questionable whether these effects remain the same under pathological conditions when mitochondrial Ca2+ ([Ca2+]m) overload occurs. While [Ca2+]m signaling is crucial for both physiological and pathological processes, molecules that facilitate [Ca2+]m uptake remain unclear. [Ca2+]m buffering is exquisitely controlled by inner mitochondrial membrane transporters, exchangers and uniporter. Several proteins have been implicated to participate in [Ca2+]m uptake, including LETM1, MICU1 and MCU. Our targeted RNAi screen identified a mitochondrial inner membrane protein, Mitochondrial Ca2+ Uniporter Regulator 1 (MCUR1) that augments [Ca2+]m uptake. MCUR1 silencing abrogates [Ca2+]m uptake under normal mitochondrial membrane potential. Our results demonstrate that MCUR1 interacts with the Ru360 sensitive core component of the mitochondrial uniporter complex, Mitochondrial Ca2+ Uniporter (MCU). Based on our recent discovery, we hypothesize that MCUR1 promotes MCU-dependent [Ca2+]m overload during I/R injury, triggering mitochondrial membrane depolarization, that results in bioenergetic collapse and mitochondrial dysfunction. This proposal applies RNAi technology, mutagenesis of MCUR1 and MCU channel, biochemical, state-of-the-art imaging and an animal model system to understand how MCUR1 elicits cardiomyocyte [Ca2+]m uptake. Based on our recent identification of MCUR1 as a regulator of the uniporter complex, here in Aim 1, we will characterize the MCUR1 role in cardiomyocyte [Ca2+]m uptake, critical regions of MCUR1-MCU interaction and transcriptional regulation of MCUR1. In Aim 2 we will investigate how MCUR1 controls mitochondrial bioenergetics, ROS production and autophagy. Finally, in Aim 3 we will apply cardiac ischemia/reperfusion in vivo murine model studies to show that knockdown of MCUR1 ameliorates I/R-induced mitochondrial dysfunction and cardiomyocyte damage. Overall, the results of these studies will advance our understanding of how MCU activity is augmented under pathophysiological conditions, and suggest new strategies for controlling [Ca2+]m influx as a new treatment for cardiovascular diseases.

描述（由申请人提供）：线粒体生物能学对于细胞的生存和死亡至关重要。生物能的维持主要取决于线粒体膜的完整性。线粒体内膜的不渗透性为氧化还原反应生成 ATP 奠定了基础。线粒体还通过快速 Ca2+ 缓冲参与胞质 Ca2+ 表型。 Ca2+ 对线粒体功能的影响有两个方面。在生理条件下，Ca2+有利于线粒体功能，刺激氧化磷酸化和ATP合成。当线粒体 Ca2+ ([Ca2+]m) 超载发生时，这些效应在病理条件下是否保持不变是值得怀疑的。虽然 [Ca2+]m 信号传导对于生理和病理过程都至关重要，但促进 [Ca2+]m 吸收的分子仍不清楚。 [Ca2+]m 缓冲由线粒体内膜转运蛋白、交换蛋白和单向转运蛋白精确控制。多种蛋白质参与 [Ca2+]m 吸收，包括 LETM1、MICU1 和 MCU。我们的靶向 RNAi 筛选发现了一种线粒体内膜蛋白，即线粒体 Ca2+ 单向转运蛋白调节器 1 (MCUR1)，它可以增强 [Ca2+]m 的吸收。 MCUR1 沉默会消除正常线粒体膜电位下的 [Ca2+]m 摄取。我们的结果表明，MCUR1 与线粒体单向转运蛋白复合物线粒体 Ca2+ 单向转运蛋白 (MCU) 的 Ru360 敏感核心成分相互作用。基于我们最近的发现，我们假设 MCUR1 在 I/R 损伤期间促进 MCU 依赖性 [Ca2+]m 过载，引发线粒体膜去极化，从而导致生物能崩溃和线粒体功能障碍。该提案应用 RNAi 技术、MCUR1 和 MCU 通道诱变、生化、最先进的成像和动物模型系统来了解 MCUR1 如何引发心肌细胞 [Ca2+]m 摄取。基于我们最近确定 MCUR1 作为单向转运蛋白复合物的调节剂，在目标 1 中，我们将描述 MCUR1 在心肌细胞 [Ca2+]m 摄取、MCUR1-MCU 相互作用的关键区域以及 MCUR1 转录调控中的作用。在目标 2 中，我们将研究 MCUR1 如何控制线粒体生物能、ROS 产生和自噬。最后，在目标 3 中，我们将应用心脏缺血/再灌注体内小鼠模型研究来表明 MCUR1 的敲低可改善 I/R 诱导的线粒体功能障碍和心肌细胞损伤。总的来说，这些研究的结果将增进我们对 MCU 活性如何在病理生理条件下增强的理解，并提出控制 [Ca2+]m 流入的新策略作为心血管疾病的新治疗方法。