Removal of damaged mitochondria by alternative autophagy

通过替代自噬去除受损的线粒体

• 批准号: 10452680
• 负责人: Junichi Sadoshima
• 金额: $ 57.15万
• 依托单位: RBHS-NEW JERSEY MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-15 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10452680
• 关键词: Aging; Autophagocytosis; Autophagosome; Biogenesis; Cardiac; Cardiac Myocytes; ChIP-seq; Chronic; Chronic Phase; Consumption; Development; Diabetes Mellitus; Differentiation and Growth; Excision; Functional disorder; Funding; Genes; Genetic Transcription; Goals; Heart; Heart Diseases; Heart Hypertrophy; Heart failure; High Fat Diet; Homeostasis; Impairment; Inflammation; Intervention; Ischemia; Knockout Mice; Knowledge; Lead; Mediating; Metabolism; Mitochondria; Molecular; Morphology; Mus; Myocardial dysfunction; Organelles; Parkin; Pathologic; Phase; Play; Production; Property; Proteins; Quality Control; RIPK1 gene; Role; Stress; TFE3 gene; Testing; Transcription Coactivator; Up-Regulation; cell type; diabetic cardiomyopathy; diabetic patient; heart cell; improved; in vivo; lipidomics; loss of function; mitochondrial dysfunction; mouse model; myocardial injury; novel; obese person; prevent; programs; protein complex; response; transcriptome

Summary Mitochondria are central intracellular organelles that mediate metabolism and ATP production. In order to maintain the function of mitochondria during stress, cardiomyocytes (CMs) have multiple layers of quality control mechanisms mediating mitochondrial fission/fusion, degradation and biogenesis. Mitophagy, a mitochondria-selective form of autophagy, is a major mechanism of degradation of damaged mitochondria and protects the heart against heart failure. In general, mitophagy is induced by the same molecular mechanisms commonly used by general autophagy, including “autophagy-related” (Atg) molecules, and additional molecules, including Pink1/Parkin. However, increasing lines of evidence suggest that mitophagy is also induced independently of conventional autophagy. During the past funding cycle, we have shown that an unconventional form of mitophagy plays a more critical role in protecting the heart during ischemia than the conventional form of mitophagy. This unconventional form of mitophagy, called alternative mitophagy, utilizes molecular machinery distinct from that used by conventional mitophagy, namely the Ulk1-Rab9-Rip1-Drp1 protein complex. Currently, the functional significance and the molecular mechanisms of alternative mitophagy remain poorly understood. Our long-term goal is to demonstrate the functional significance of alternative mitophagy in the heart during chronic and more pathologically relevant conditions in vivo, elucidate the underlying molecular mechanisms, and eventually apply our knowledge to treat heart disease by stimulating alternative mitophagy. Interestingly, although conventional autophagy and mitophagy are activated in response to high fat diet (HFD) consumption in the mouse model of diabetic cardiomyopathy, their activation is transient and they protect the heart only during the early phase of HFD consumption. On the other hand, an unconventional form of mitophagy is activated in a more prolonged manner and appears to play an essential role in protecting the heart during the chronic phase of HFD consumption. We here hypothesize that alternative mitophagy is the predominant form of mitophagy in the heart during the chronic phase of HFD consumption and plays an essential role in protecting the heart against diabetic cardiomyopathy. Alternative mitophagy is activated through a TFE3-dependent transcriptional program and the direct association of a large protein complex, containing Drp1 and Drp1 interacting proteins, with mitochondria. We will test our hypothesis using unique indicators of mitophagy, genetically altered mouse models, morphological analyses, including immunogold analyses, lipidomics, transcriptome analyses, and ChIP-sequencing analyses. Our study will demonstrate a novel and targetable mitochondrial quality control mechanism during the chronic development of diabetic cardiomyopathy. Our study should lead to the development of novel interventions to maintain the quality of mitochondria in diabetic patients and alleviate their cardiac complications, including cardiac hypertrophy/dysfunction, lipotoxicity, and inflammation.

总结 线粒体是介导代谢和ATP产生的中心细胞内细胞器。为了 维持线粒体的功能，在压力下，心肌细胞（CM）具有多层质量 调节线粒体分裂/融合、降解和生物发生的控制机制。线粒体自噬a 线粒体选择性自噬是降解受损线粒体的主要机制， 防止心脏衰竭一般来说，线粒体自噬由相同的分子机制诱导， 通常由一般自噬使用，包括“自噬相关”（Atg）分子，和另外的 分子，包括Pink 1/Parkin。然而，越来越多的证据表明，线粒体自噬也是 诱导独立于传统的自噬。在过去的融资周期中，我们已经表明， 非常规形式的线粒体自噬在缺血期间保护心脏方面起着比 线粒体自噬的传统形式。这种非传统的线粒体自噬形式，称为替代性线粒体自噬， 分子机制不同于传统的线粒体自噬，即Ulk 1-Rab 9-Rip 1-Drp 1 蛋白质复合物目前，选择性线粒体自噬的功能意义和分子机制 人们对它了解仍然很少。我们的长期目标是证明替代性的功能意义 在体内慢性和更多病理学相关条件下心脏中的线粒体自噬，阐明 潜在的分子机制，并最终应用我们的知识来治疗心脏病， 选择性线粒体自噬有趣的是，尽管传统的自噬和线粒体自噬在反应中被激活， 在糖尿病心肌病小鼠模型中，高脂饮食（HFD）消耗，它们的激活是短暂的 并且它们仅在食用HFD的早期阶段保护心脏。另一方面， 非传统形式的线粒体自噬以更长的方式被激活，似乎在细胞分裂中起着重要的作用。 在HFD消耗的慢性阶段保护心脏的作用。我们在此假设 交替性线粒体自噬是慢性期心脏线粒体自噬的主要形式， HFD的消耗在保护心脏免受糖尿病心肌病方面发挥着重要作用。 选择性线粒体自噬通过TFE 3依赖性转录程序激活，而直接线粒体自噬通过TFE 3依赖性转录程序激活。 含有Drp 1和Drp 1相互作用蛋白的大蛋白复合物与 线粒体我们将使用线粒体自噬的独特指标来测试我们的假设， 模型，形态学分析，包括免疫金分析，脂质组学，转录组学分析， ChIP测序分析。我们的研究将证明一种新的和有针对性的线粒体质量控制 糖尿病性心肌病慢性发展过程中的机制。我们的研究应该会导致 开发新的干预措施，以维持糖尿病患者线粒体的质量， 他们的心脏并发症，包括心脏肥大/功能障碍、脂毒性和炎症。