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Dynamin-Related Protein Drp1 Regulates Cardiac Excitation-Contraction-Bioenergetics Coupling

动力相关蛋白 Drp1 调节心脏兴奋-收缩-生物能耦合

基本信息

批准号：
10063889
负责人：
Shey-Shing Sheu
金额：
$ 62.87万
依托单位：
THOMAS JEFFERSON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-01-01 至 2023-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10063889
关键词：
Actins Adrenergic Receptor Adult Architecture Binding Biochemistry Bioenergetics Biological Assay Biological Markers Brain Cardiac Cardiac Myocytes Cardiomyopathies Cell Death Cell Nucleus Cell Volumes Cell division Cells Cellular biology Cessation of life Chronic Coupling Cytoskeleton Data Diabetes Mellitus Disease Dynamin Echocardiography Electron Microscopy Electrons Endoplasmic Reticulum Energy Metabolism Exhibits F-Actin Face Fibroblasts Fluorescence Resonance Energy Transfer Frequencies Functional disorder Gap Junctions Generations Genes Guanosine Triphosphate Heart Heart Hypertrophy Heart failure Hot Spot Image In Situ In Vitro Infusion procedures Injury Isoproterenol Knock-in Knock-out Knowledge Lead Left Link Location Malignant Neoplasms Mammalian Cell Mediating Membrane Membrane Potentials Messenger RNA Microfilaments Microscopy Mitochondria Molecular Molecular Biology Movement Muscle Cells Myocardial dysfunction Myocardium Myofibrils NMR Spectroscopy Neurodegenerative Disorders Northern Blotting Optic Atrophy Organelles Oxidation-Reduction Phosphorylation Physiological Physiology Process Production Proteins Quality Control RNA Interference Rattus Reactive Oxygen Species Regulation Reporting Research Personnel Resolution Respiration Role Sarcolemma Sarcoplasmic Reticulum Signal Pathway Signal Transduction Site Skeletal Muscle Stress Techniques Testing Therapeutic Agents Tissues Ventricular Work Workload base calmodulin-dependent protein kinase II cell injury cell type density human disease insight mitochondrial membrane mitochondrial permeability transition pore mouse model oocyte maturation overexpression recruit respiratory targeted treatment

项目摘要

Project Summary/Abstract Mitochondrial dynamics, including fission, fusion, and movement, is a fundamental mechanism in regulating mitochondrial function. Dynamin-related protein 1 (Drp1) is the major GTP hydrolyzing protein that is responsible for fission. Studies have shown that Drp1 is abundantly expressed in adult cardiac myocytes. Paradoxically, compared to numerous cell types, adult cardiac myocytes exhibit very low frequency in mitochondrial fission. This dichotomy between the abundance of Drp1 and scarcity of mitochondrial fission has prompted us to investigate the non-canonical roles of Drp1 in cardiac muscle cells. We hypothesize that Drp1 is strategically accumulated in the mitochondria associated sarcoplasmic reticulum (SR) membrane (MAM). During excitation- contraction coupling, the localized high Ca2+ in the SR-mitochondria junctions further increases the translocation of nearby cytosolic Drp1 to mitochondria. Then, Drp1 is anchored firmly in the MAM by actin. The activation of Drp1 leads to enhanced mitochondrial respiration for ATP generation as such the heart can work most effectively and sustainably. However, excessive Drp1 activation leads to persistent mitochondrial transition pore opening and excessive reactive oxygen species (ROS) generation that causes cell injury and death. The following three specific aims are proposed to test this hypothesis. Aim 1: To determine whether and how Drp1 is preferentially localized in the SR-mitochondria junctions. Aim 2: To determine the molecular mechanisms by which Drp1 regulates excitation-contraction-bioenergetics coupling. Aim 3: To determine how chronic over activation of Drp1 leads to dysfunction in the stressed heart. We will employ multiple techniques, including biochemistry (from in vitro to in situ assays), molecular biology (gene knock in or knock out, overexpression, RNA interference), cell biology (confocal, fluorescence resonance energy transfer, super-resolution microscopy, electron microscopy), cardiac physiology (echocardiogram, NMR spectroscopy), and isoproterenol infusion mouse model of cardiac hypertrophy and failure, to obtain experimental results that will lead to mechanistic insights. Successful completion of the proposed aims will allow us to introduce a new paradigm that describes the regulation of excitation-contraction-bioenergetics-ROS nexus by Drp1 through localized Ca2+ activation and actin anchoring. This fundamental signaling mechanism will describe not only how a healthy heart can perform perpetually in face of enormous workload but also why the over activation of this unique process can lead to heart failure. Finally, this new knowledge will provide new insights in developing and discovering therapeutic agents targeting Drp1-mediated signaling pathways for treating heart failure.

项目总结/摘要线粒体动力学，包括分裂，融合和运动，是一个基本的机制，调节线粒体功能。动力蛋白相关蛋白1（Dynamin-related protein 1，Drp 1）是GTP的主要水解酶负责裂变的蛋白质。研究表明，Drp 1在哺乳动物中大量表达，成体心肌细胞有趣的是，与许多细胞类型相比，成年心肌细胞线粒体分裂的频率很低这种丰富的 drp 1和线粒体分裂的缺乏促使我们研究非经典的作用， Drp 1在心肌细胞中的表达。我们假设Drp 1是策略性地积累在线粒体相关肌浆网（SR）膜（MAM）。在激发过程中- 收缩偶联，SR-线粒体连接中的局部高Ca 2+进一步增加附近的胞质Drp 1易位到线粒体。然后，Drp 1牢固地锚定在通过肌动蛋白。Drp 1的激活导致线粒体对ATP的呼吸增强因此，这一代人的心脏可以最有效和可持续地工作。但过度 drp 1激活导致持续的线粒体过渡孔开放和过度的反应性氧物质（ROS）的产生导致细胞损伤和死亡。以下三种特定目的是为了检验这一假设。目的1：确定Drp 1是否以及如何被优先定位在SR-线粒体连接处。目的2：确定其分子量 Drp 1调节兴奋-收缩-生物能量学耦合的机制。目标3：确定Drp 1的慢性过度激活如何导致应激心脏功能障碍。我们将采用多种技术，包括生物化学（从体外到原位测定），分子生物学，生物学（基因敲入或敲除，过表达，RNA干扰），细胞生物学（共聚焦，荧光共振能量转移，超分辨率显微镜，电子显微镜），心脏生理学（超声心动图，NMR光谱学）和异丙肾上腺素输注小鼠心肌肥大和衰竭模型，以获得将导致机械的洞察力。成功完成拟议目标将使我们能够推出新的该范式描述了兴奋-收缩-生物能学-ROS关系的调节， Drp 1通过局部Ca 2+激活和肌动蛋白锚定。这个基本的信号这一机制不仅描述了一个健康的心脏如何在面对疾病时永远发挥作用，巨大的工作量，但也为什么过度激活这个独特的过程会导致心脏失败最后，这些新知识将为开发和发现用于治疗心力衰竭的靶向Drp 1介导的信号传导途径的治疗剂。