Mechanisms of regulation of mitochondrial H+ leak and thermogenesis

项目摘要 线粒体通过将营养物质转化为质子(H+)的电化学梯度来控制细胞代谢 通过线粒体膜(IMM)产生细胞的通货三磷酸腺苷(ATP)和热量(称为 线粒体产热作用)。H+在两种形式的能量之间分配的精确平衡 生产，三磷酸腺苷和热量，定义了细胞的代谢动态平衡。棕色脂肪和米色脂肪线粒体 专门通过解偶联蛋白1(UCP1)产生热量。然而，即使在其他组织中， 线粒体产热作用占线粒体总能量产生的25%，因此可以 对整个身体的生理有相当大的影响。线粒体产热不仅对 保持核心体温，也是燃烧多余卡路里以防止饮食的过程。 诱导性肥胖。此外，它还减少了线粒体产生的活性氧物种(ROS)，以 保护细胞免受氧化损伤。此外，化学解偶联剂，如2，4-二硝基苯酚(DNP)， 被认为不依赖于蛋白质而增加H+泄漏，是迄今为止最有效的减肥药物。 因此，线粒体产热是细胞新陈代谢的强大调节器，也是一种 对这一基本过程的理解将有助于制定治疗策略 与许多与线粒体功能障碍相关的病理疾病作斗争，包括代谢综合征 以及与年龄相关的疾病。不幸的是，控制急性激活的确切分子机制 线粒体的生热作用还不是很清楚。这种信息的缺乏在很大程度上是由于缺乏 直接测量跨IMM的H+电流的方法。基于以下方面的方法论开发 膜片钳技术首次允许通过每个组织的IMM直接研究H+泄漏和 线粒体转运蛋白UCP1和ADP/ATP转运蛋白的首次生物物理特征 (AAC)，它们是这次H+泄漏的调解人。这种独特的方法现在提供了前所未有的高度- 1)线粒体离子通道和转运体的直接功能分析 线粒体生热作用；2)化学解偶联剂如DNP的作用机制。使用 结合现代细胞和分子技术的新的线粒体膜片钳实验，这 研究项目将为控制细菌产热能力的机制提供新的见解 线粒体以及如何将其作为治疗的靶点。

Project Summary Mitochondria control cell metabolism by converting nutrients into an electrochemical gradient of protons (H+) across the inner mitochondrial membrane (IMM) to generate ATP, the currency of the cell, and heat (called mitochondrial thermogenesis). A precise balance in the distribution of H+ between the two forms of energy production, ATP and heat, defines the metabolic homeostasis of the cell. Brown fat and beige fat mitochondria specialize in the production of heat via the uncoupling protein 1 (UCP1). However, even in other tissues, mitochondrial thermogenesis accounts for 25% of total mitochondrial energy production and can therefore have a considerable impact on the physiology of the entire body. Mitochondrial thermogenesis is not only essential for maintaining core body temperature, it is also the process by which excess calories are burned to prevent diet- induced obesity. In addition, it reduces the production of reactive oxygen species (ROS) by the mitochondria to protect cells from oxidative damage. In addition, chemical uncouplers such as 2,4-dinitrophenol (DNP), which are believed to increase H+ leak independently of proteins, are the most effective anti-obesity drugs to date. Thus, mitochondrial thermogenesis is a powerful regulator of cellular metabolism, and a mechanistic understanding of this fundamental process will help in the development of therapeutic strategies to combat many pathologies associated with mitochondrial dysfunction, including metabolic syndrome and age-related disorders. Unfortunately, the precise molecular mechanisms that control the acute activation of thermogenesis in the mitochondria are poorly defined. This lack of information is largely due to a dearth of methods for direct measurement of H+ currents across the IMM. The development of a methodology based on the patch-clamp technique allows for the first time the direct study of H+ leak through the IMM of each tissue and the first biophysical characterization of mitochondrial transporters, such as UCP1 and the ADP/ATP transporter (AAC), which are the mediators of this H+ leak. This unique approach now provides an unprecedented high- resolution direct functional analysis of 1) the mitochondrial ion channels and transporters responsible for mitochondrial thermogenesis and 2) the mechanisms of action of chemical uncouplers such as DNP. Using the new mitochondrial patch-clamp assay combined with modern cellular and molecular techniques, this research project will provide new insights into the mechanisms that control the thermogenic capacity of the mitochondria and how they can be targeted for therapeutic purposes.