Cardiac Mitohormesis Protects Against Diabetic Cardiomyopathy Through Mitophagy

项目摘要 这份建议书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。 王，作为一名独立调查员的职业生涯。该计划将扩大王博士的科学背景， 通过提供线粒体生物学方面的额外技术培训和专业知识， 在干细胞生物学领域，王博士已经取得了重大成就。导师是博士。 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。建议的导师是一位在干细胞方面具有重要专业知识的医生科学家 生物学和心血管疾病建模专家。K99阶段将包括结构化的 主要导师的指导，与咨询委员会的补充会议，正式课程， 一个具有挑战性的研究项目和一个职业转型项目。 糖尿病是一种流行病，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死亡的主要原因， 冠状动脉疾病（CAD）。然而，糖尿病患者也患有糖尿病心肌病 (DCM)与高血压或CAD的血管效应无关。DCM的潜在机制是 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， 在肌肉中，自噬/溶酶体系统提供蛋白水解机制来调节蛋白质周转， 降解线粒体自噬是一种自噬过程，专门清除受损的线粒体， 是至关重要的适当维护心脏功能时，在过量的营养。线粒体自噬在 糖尿病心脏目前尚不清楚，在本提案中，Ong博士打算了解以下方面的重要性： 线粒体自噬在扩张型心肌病中的作用，并探索调节线粒体自噬的潜在机制， 转化科学 结合Ong博士在线粒体生物学方面的专业知识和他在干细胞生物学方面的技能， 他与吴博士合作开发的基因组学/蛋白质组学生物学使他处于一个独特的位置， 能够研究线粒体自噬在人类心肌细胞中的重要性及其分子机制 以前所未有的方式与之相关。王博士已经生成了初步数据 证明人诱导多能干细胞衍生的心肌细胞中线粒体自噬受损 （iPSC-CM），尽管存在异质性应答。王博士会努力 结论性地证明受损的线粒体自噬增加了iPSC-CM对高血糖的易感性， 损伤，并可能识别线粒体自噬的分子特征，这可能在未来用于 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， 一个有趣的现象是，抗高血糖应激的细胞与 非典型的线粒体自噬，尽管受损的典型自噬。因此，王博士将调查 线粒体自噬受损的机制基础以及轻度ROS对线粒体自噬的潜在调节（Aim 2）。 这是由于Ong博士的观察，即用抗氧化剂治疗iPSC-CM会使iPSC-CM的有害作用恶化。 高血糖症的影响，表明ROS的适应性作用（mitochormesis）。在最后的目标中，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 将已知的糖尿病易感基因导入同基因健康系。这些线路组将为Ong博士提供 药物筛选的原理验证平台，应基于两种形式：（一）测试目前 可用的抗糖尿病药物，因为某些药物与不良心脏结局相关，以及（ii） 测试线粒体自噬诱导剂，可以防止高血糖损伤，这是基于我的 早期发现（目标3）。这项工作的意义将是确定适当的线粒体 体内平衡作为预防扩张型心肌病的必要条件，可能涉及非典型的线粒体自噬， 氧化应激作为有丝分裂激素分子的重要性，并提供了人类心肌细胞独特的- 基于平台的药物测试。在一个强有力的指导环境中完成这些研究将奠定 王博士的过渡到他自己的独立研究计划的基础。

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.