Mechanistic insights into the cardioprotective effects of mABC1 protein

项目简介/摘要申请人侯赛因·阿德哈里，医学博士，博士，2004年在约翰霍普金斯医院完成住院医师和研究员培训，此后一直担任西北大学医学、分子药理学和生物化学助理教授。他刚刚完成了K08资助(2005年资助，优先级分数为120)，并有一项有效的R01资助，该资助是在2007年资助的，分数为第4个百分位数。应聘者对在学术机构从事基础科学研究和病人护理有着浓厚的兴趣，西北大学已经并将继续提供良好的支持环境。Ardehali博士的长期目标是成为心脏生物学领域的一名成功的研究者，并将基础科学发现应用于临床实践，希望开发治疗缺血性心脏病的新方法。该提案详细介绍了Ardehali博士的研究生涯发展计划，该计划包括四个目标：1)参加科学丰富计划，2)在他的临床和科学优势的基础上建立不同的研究领域，3)提高实验室的方法能力，4)培养与该领域领先科学家的合作。申请人的主要关注点是一种新的线粒体蛋白--线粒体ATP结合盒蛋白1(MABC1)的功能特征。申请人已经证明，mABC1的过度表达可以防止细胞死亡，但该蛋白的主要功能尚不清楚。申请人实验室的最新结果表明，在分离的心肌细胞中，mABc1的下调导致线粒体铁增加，胞质铁硫簇(Fe/S)含有蛋白质的活性降低。他还培育了心脏特异的mABC1基因敲除(KO)和转基因(TG)动物。心脏特异的mABC1KO导致线粒体铁积累并导致心肌病的发生，而mABC1Tg小鼠对阿霉素诱导的心脏毒性具有抵抗力，并具有较低的线粒体铁水平。综上所述，这些结果提示mABc1参与了线粒体铁的稳态和铁/S簇的转运，心脏中该蛋白的过表达对阿霉素引起的心脏毒性具有保护作用。这一建议的中心假设是mABC1受mTOR途径调控，mABC1的心脏保护作用是通过减少自噬和改善线粒体的生物发生和功能来实现的。在目标1中，申请者将评估mTOR途径对mABC1的调控。在目标2中，将评估mABC1调节对细胞铁通量的影响，目标3将通过研究线粒体功能和自噬对mABC1调节的响应来评价mABC1的细胞保护作用的机制。建议的研究是符合逻辑和令人信服的实验序列，旨在跟进我们的关键观察结果，即mABc1对细胞死亡具有保护作用，并在线粒体铁稳态和铁/S簇输出线粒体方面发挥作用。

DESCRIPTION (provided by applicant): The Project Summary/Abstract The applicant, Hossein Ardehali, M.D., Ph.D., completed his residency and fellowship training at The Johns Hopkins Hospital in 2004 and has been an Assistant Professor of Medicine, Molecular Pharmacology and Biological Chemistry at Northwestern University since then. He just completed a K08 grant (funded in 2005 with a priority score of 120), and has an active R01 grant that was funded in 2007 with a score of 4th percentile. The candidate has a solid interest in pursuing basic science research along with patient care in an academic institution, and Northwestern has and will continue to provide an excellent supportive environment. Dr. Ardehali's long term goals are to become a successful investigator in the field of cardiobiology and to apply basic science discoveries to clinical practice with the hope of developing new treatments for ischemic heart disease. This proposal details Dr. Ardehali's research career development plan that integrates four objectives: 1) to attend scientific enrichment programs, 2) to establish distinct areas of research that builds upon his clinical and scientific strengths, 3) to improve the methodological capability of the lab, and 4) to cultivate collaboration with leading scientists in the field. The applicant's major focus is on functional characterization of a novel mitochondrial protein, mitochondrial ATP-binding cassette protein 1 (mABC1). The applicant had shown that overexpression of mABC1 leads to protection against cell death, but the primary function of the protein is not known. Recent results from the applicant's lab indicate that downregulation of mABC1 in isolated cardiomyocytes results in an increase in mitochondrial iron and a reduction in the activity of cytosolic iron-sulfur cluster (Fe/S) containing proteins. He has also generated cardiac specific mABC1 knockout (KO) and transgenic (TG) animals. Heart specific mABC1 KO results in mitochondrial iron accumulation and leads to the development of cardiomyopathy, while mABC1 TG mice are resistant to doxorubicin-induced cardiotoxicity and have lower mitochondrial iron levels. Together, these results suggest that mABC1 is involved in mitochondrial iron homeostasis and the transport of Fe/S clusters out of the mitochondria, and overexpression of the protein in the heart protects against doxorubicin induced cardiotoxicity. The central hypothesis of this proposal is that mABC1 is regulated by mTOR pathway and that the cardioprotective effects of mABC1 are through a reduction in autophagy and an improvement in mitochondrial biogenesis and function. In Aim 1, the applicant will evaluate regulation of mABC1 by mTOR pathway. In Aim 2, the effects of mABC1 modulation on cellular iron flux will be assessed, and Aim 3 will evaluate the mechanism for the cytoprotective effects of mABC1 by studying mitochondrial function and autophagy in response to mABC1 modulation. The proposed studies are logical and compelling sequence of experiments designed to follow up on our key observation that mABC1 is protective against cell death and plays a role in mitochondrial iron homeostasis and Fe/S cluster export out of mitochondria.