Cardiac Mitohormesis Protects Against Diabetic Cardiomyopathy Through Mitophagy

项目总结 这份提案描述了一个为期五年的职业发展计划，为候选人Sang-Ging博士做准备 作为一名独立调查员的职业生涯。这项计划将扩大王博士的科学背景 通过提供额外的线粒体生物学和专业知识方面的技术培训和专业知识进行心血管研究 干细胞生物学，这是王博士已经取得重大成就的领域。导师是Dr。 约瑟夫·吴，医学/心脏病学教授，斯坦福大学心血管研究所所长 斯坦福大学。被推荐的导师是一位在干细胞方面拥有丰富专业知识的内科科学家。 他是心血管疾病建模方面的专家。K99阶段将由结构化的 主要导师的指导，与咨询委员会的补充会议，正式的课程作业， 一项具有挑衅性的研究项目，以及一项职业转型计划。 糖尿病正处于流行阶段，预计到2025年将有3亿人患有糖尿病。 心血管疾病是这些患者的主要死因，其中 因素是冠心病(CAD)。然而，糖尿病患者也患有糖尿病心肌病。 (DCM)不受高血压或冠心病的血管影响。DCM背后的机制是 目前尚不清楚，目前还没有具体有效的治疗方法。在所有细胞中，包括心脏细胞 自噬/溶酶体系统提供蛋白分解机制来调节蛋白质的周转和 退化。有丝分裂是一种自噬过程，它专门移除受损的线粒体，并可能 在营养过剩的情况下，对心脏功能的正确维持至关重要。有丝分裂在细胞分裂中的作用 糖尿病心脏目前尚不清楚，在这项建议中，王博士打算了解 DCM中的有丝分裂吞噬，并探索调节有丝分裂的潜在机制，这可能有助于 翻译科学。 将王博士在线粒体生物学方面的专业知识与他在干细胞生物学和 他在与吴博士合作期间正在开发的基因组学/蛋白质组学生物学使他处于独特的地位 能够研究人类心肌细胞有丝分裂的重要性及其分子机制 以前所未有的方式与之相关的。王博士已经生成了初步数据 证明人类诱导的多能干细胞来源的心肌细胞有丝分裂功能受损 (IPSC-CMS)虽然存在异质性反应，但仍处于高血糖状态。王博士将寻求 结论：吞噬核分裂功能受损增加了IPSC-CMS对高血糖的易感性 并潜在地鉴定吞噬有丝分裂的分子特征，这在未来可能对 预测对过量葡萄糖的反应(目标1)。王博士的初步结果还显示， 有趣的现象是，抵抗高血糖应激的细胞与激活 尽管经典自噬受损，但非经典有丝分裂吞噬。因此，王博士将调查 丝裂原吞噬功能受损的机制基础以及轻度ROS对有丝分裂功能的潜在调节(目标2)。 这是因为王博士观察到，用抗氧化剂治疗IPSC-CMS会恶化有害的 高血糖的影响，表明ROS(有丝分裂兴奋)的适应性作用。在最终目标中，王博士将 获得来自患有和不患有DCM的糖尿病患者的额外IPSC系，以及引入 已知的糖尿病易感基因进入等基因的健康品系。这些线路组将为王博士提供一个 药品筛选的原则证明平台应基于两种形式：(I)目前的测试 现有的抗糖尿病药物，因为一些药物与不良心脏结果有关，以及(Ii) 检测可能预防高血糖损害的丝裂原诱导剂，这是基于我的 更早的发现(目标3)。这项工作的意义在于识别合适的线粒体。 动态平衡是预防扩张型心肌病的一项要求，它可能涉及非典范的有丝分裂，强调 氧化应激作为有丝分裂激素分子的重要性，并提供了一种独特的人类心脏细胞- 基于平台的药物检测。在强有力的指导环境中完成这些研究将为 为王博士过渡到他自己的独立研究项目奠定了基础。

PROJECT SUMMARY This proposal describes a five-year career development program to prepare the candidate, Dr. Sang-Ging Ong, for a career as an independent investigator. This program will expand Dr. Ong's scientific background in cardiovascular research by providing additional technical training and expertise in mitochondria biology and stem cell biology, areas in which Dr. Ong has already made significant achievements. The mentor is Dr. Joseph Wu, a Professor of Medicine/Cardiology and Director of the Stanford Cardiovascular Institute at Stanford University. The proposed mentor is a physician scientist with significant expertise in stem cell biology and is an expert in cardiovascular disease modeling. The K99 phase will consist of structured mentorship by the primary mentor, complementary meetings with the advisory committee, formal coursework, a provocative research project, and a program of career transition. Diabetes is at epidemic proportions with 300 million people expected to suffer from diabetes by 2025. Cardiovascular disease is the major cause of death among these patients of which the major contributing factor is coronary artery disease (CAD). However, diabetic patients also suffer from diabetic cardiomyopathy (DCM) independent of the vascular effects of hypertension or CAD. The mechanisms underlying DCM are unclear, and there are currently no specific effective treatments for it. In all cells, including those of heart muscle, the autophagy/lysosome system provides proteolytic mechanisms to regulate protein turnover and degradation. Mitophagy is an autophagic process that specifically removes damaged mitochondria and may be crucial for the proper maintenance of cardiac function when in excess nutrient. The role of mitophagy in the diabetic heart is currently unknown, and in this proposal, Dr. Ong intends to understand the importance of mitophagy in DCM, and explore the underlying mechanisms that regulate mitophagy which may help in translational science. Combining Dr. Ong's expertise in mitochondrial biology with his skills in stem cell biology and genomics/proteomics biology that he is developing while working with Dr. Wu puts him in a unique position to be able to study the importance of mitophagy in human cardiac cells and the molecular mechanisms pertaining to it in ways that have not been done before. Dr. Ong has generated preliminary data demonstrating that mitophagy is impaired in human induced pluripotent-stem cells-derived cardiomyocytes (iPSC-CMs) subjected to hyperglycemia although there is a heterogeneous response. Dr. Ong will seek to conclusively prove that impaired mitophagy increases the susceptibility of iPSC-CMs to hyperglycemic damage, and to potentially identify a molecular signature of mitophagy which may be useful in the future for predicting response to excess glucose (Aim 1). Dr. Ong's preliminary results have also revealed an interesting phenomenon in that cells resistant to hyperglycemic stress are associated with an activation of non-canonical mitophagy despite impaired canonical autophagy. Hence Dr. Ong will investigate the mechanistic basis of impaired mitophagy and also the potential regulation of mitophagy by mild ROS (Aim 2). This is due to Dr. Ong's observation that treatment of iPSC-CMs with antioxidants worsen the detrimental effects of hyperglycemia, indicating an adaptive role of ROS (mitohormesis). In the final aim, Dr. Ong will obtain additional iPSC lines derived from diabetic patients with and without DCM, as well as introducing known diabetes susceptibility genes into isogenic healthy lines. These groups of lines will provide Dr. Ong a proof-of-principle platform for drug screening which shall be based on two formats: (i) testing for currently available anti-diabetic drugs as some drugs have been associated with adverse cardiac outcomes, and (ii) testing for mitophagy inducers which may protect against hyperglycemic damage which is based on my earlier findings (Aim 3). The implications of this work will be the identification of proper mitochondrial homeostasis as a requirement for prevention of DCM which may involve non-canonical mitophagy, highlight the importance of oxidative stress as mitohormetic molecules, and provide a unique human cardiac cells- based platform for drug testing. Completing these studies in a strong mentored environment will lay the foundation for Dr. Ong's transition to his own independent research program.