Mitochondrial ROS mapping and control with sub-organellar resolution

这个项目旨在促进我们对线粒体如何在严重应激下保持其功能的理解。线粒体是动物细胞的基本组成部分，对正常的细胞代谢和生理至关重要。线粒体功能障碍与衰老和许多人类疾病有关，因此维持其正常功能是非常重要的。线粒体产生称为活性氧簇(ROS)的小分子，它对细胞内的信号传递很重要，但在高水平时会造成极大的破坏。该项目将阐明线粒体内ROS在哪里产生，以及它们的水平是如何保持的。这反过来将使我们能够更好地了解它们的局部影响，因为它们是由内部线粒体结构决定的，这是开发有效和有针对性的策略来控制它们的第一步。这是绝对关键的，因为保持它们水平的精细平衡使得ROS在低水平时作为信号分子是有益的，或者在高水平时恢复为细胞的破坏剂。我们将合成一系列小的化学分子，这些小分子可以专门检测不同的ROS，并通过针对这些标记特异地附着在这些探针上的选择性蛋白质标记，将它们定位在特定的线粒体亚室中。在健康条件下，这些蛋白质标签的输入是由线粒体跨膜能量梯度提供动力的。我们已经发现，一种抗氧化蛋白质是由一个不需要这种能量梯度的系统输入的，这是值得注意的，因为这种梯度在严重的氧化还原压力条件下会受到影响。我们将利用我们在受损线粒体中这一新的输入途径的知识，首次研究ROS在这种受损线粒体中的分布和影响。我们的发现为探索以前难以捉摸的具有前所未有的亚线粒体分辨率的ROS分布的机制提供了第一个机会。这对于有效地保护细胞免受有害的氧化应激是至关重要的。我们在这个项目中提出的跨学科方法将进一步加深我们对线粒体靶向和细胞应激机制的理解，并可能为理解真核细胞中氧化应激信号的协调提供一个新的范式。

This project aims to advance our understanding of how mitochondria are able to retain their function under severe stress. Mitochondria are fundamental components of animal cells that are essential for proper cell metabolism and physiology. Mitochondrial dysfunction is linked to ageing, and to numerous human pathologies and so the maintenance of their normal function is very important. Mitochondria produce small molecules called reactive oxygen species (ROS) which are important for signalling in the cell but at high levels become highly damaging. The project will elucidate where within mitochondria ROS are produced, and how their levels are maintained. This will in turn allow us to understand better their localised effects as they are dictated by the internal mitochondrial architecture as a first step to develop efficient and targeted strategies to control them. This is absolutely critical because maintaining a fine balance of their levels makes all the difference for ROS being beneficial as signalling molecules in low levels or reverting to damaging agents for the cell at high levels.We will synthesise a series of small chemical molecules that can specifically detect distinct ROS and localise them in specific sub-mitochondrial compartments by targeting to these compartments selective protein tags that specifically attach to these probes. Under healthy conditions the import of these protein tags is powered by the mitochondrial transmembrane energy gradient. We have discovered that one antioxidant protein is imported by a system that does not require this energy gradient, which is remarkable and just as well since that gradient is compromised under severe redox stress conditions. We will make use of our knowledge of this new import pathway in compromised mitochondria to address for the first time the ROS distribution and effects in such damaged mitochondria. Our findings offer the first opportunity to explore the mechanisms of a previously elusive ROS distribution with unprecedented sub-mitochondrial resolution. This is critical to effectively defend cells against deleterious oxidative stress. Our interdisciplinary approach outlined in this project will further our understanding of mitochondrial targeting and cell stress mechanisms and it is likely to provide a novel paradigm for understanding the coordination of oxidative stress signalling in eukaryotic cells.