Mechanisms of Mitochondrial Ultrastructural Changes and Metabolic Dysfunction Caused by Calcium Overload

项目摘要/摘要： 心肌缺血/再灌注(IR)是一种由钙引起的线粒体功能障碍的损伤 超载。虽然线粒体钙动力学和分子通路已经被广泛研究，但很少 已知线粒体如何积累和储存钙，以及钙超载如何影响线粒体 功能。这一点很重要，因为心肌梗塞后心脏组织和细胞死亡的主要原因是 由线粒体钙超载介导。由于没有适当的治疗方法，因此 钙储存及其对线粒体功能的影响有待进一步研究。在这里，我们展示了初步的 结果揭示了在钙化过程中冠突结构和线粒体功能之间前所未有的联系 超载。目前的数据表明，在钙超载期间保留结缔组织可以预防 钙超载。证实这一假设将增加一种令人兴奋的新治疗方法，并将 即刻发挥蛋白不被认为是治疗IR损伤的药物靶点。这项提案的目标是 1)表征和量化钙隔离系统及其对线粒体的直接影响 功能，2)确定与线粒体超微结构相关的冠突重构对功能的影响 钙超载，以及3)确定已知的钙隔离系统的调节器如何改变 线粒体功能。该提案中的实验方法将使用最新的先进低温- EM、荧光分光光度法、体外心脏灌流系统和高分辨率呼吸测量法。生物能量和 功能数据将从健康、缺血和IR损伤的分离的心肌线粒体中进行测量 豚鼠的心脏。此外，来自该奖学金的支持将用于获得试验性和 学术技能是提案成功的关键。这些将通过采用高质量的 在密歇根州立大学开设的课程、实践培训、研讨会以及地区和国家会议。采集 通过F31线粒体和细胞生理学奖获得的科学专业知识将为 通过演讲、海报和手稿写作改善科学交流。通过以下方式获得的机会 F31奖将继续并扩大这项工作，以涵盖以下生物能量后果 线粒体钙超载和线粒体超微结构与以下病理生理情景相关 作为IR损伤。奖学金获得者、赞助商、共同赞助商、 合作者，机构对卓越的承诺是通向独立的最佳途径，这将 帮助释放作为一名成功科学家的潜力。

Project Summary/Abstract: Myocardial ischemia/reperfusion (IR) is an injury preceded by mitochondrial dysfunction caused by calcium overload. While mitochondrial calcium dynamics and molecular pathways have been extensively studied, little is known on how mitochondria accumulate and store calcium and how calcium overload effects mitochondrial function. This is significant since the main cause of cardiac tissue and cell death after a myocardial infarction is mediated by mitochondrial calcium overload. As there are no adequate treatments available, the nature of calcium storage and its impact on mitochondrial function requires further study. Herein, we show preliminary results that reveal an unprecedented link between cristae structure and mitochondrial function during calcium overload. The presented data suggest that preserving cristae during calcium overload confer protection against calcium overload. Confirming this hypothesis will add an exciting new therapeutic approach and puts in immediate play proteins not considered as drug targets to treat IR injury. The objectives of this proposal are 1) to characterize and quantify the calcium sequestration system and the direct effects on mitochondrial function, 2) to determine the functional impact of cristae remodeling in mitochondria ultrastructure associated with calcium overload, and 3) establish how known modulators of the calcium sequestration system alter mitochondrial function. The experimental approach in this proposal will use recent methods of advanced cryo- EM, spectrofluorimetry, ex vivo heart perfusion system, and high-resolution respirometry. Bioenergetic and functional data will be measured from isolated cardiac mitochondria from healthy, ischemic, and IR injured guinea pig hearts. In addition, support from this fellowship will be directed to acquire experimental and academic skills sets that are key to the proposal success. These will be approached by taking high-quality courses offered at MSU, hands-on training, workshops, and regional and national conferences. Gathering scientific expertise via the F31 Award in mitochondria and cellular physiology will provide opportunities for improving scientific communication through talks, posters, and manuscript writing. The opportunity granted via the F31 Award will continue and expand this work to encompass the bioenergetic consequences between mitochondrial calcium overload and mitochondrial ultrastructure related to a pathophysiological scenario such as IR injury. The combined efforts of the fellowship award, extensive expertise of sponsors, co-sponsors, collaborator, and the institution’s commitment to excellence is an optimal pathway to independence that will help unlock the potential as a successful scientist.