Iron in Mitochondrial Physiology and Disease

描述（由申请人提供）：细胞铁代谢的很大一部分发生在线粒体中，包括铁进口，铁硫簇组装和血红素生物合成。一些血红素和铁硫簇被安装到呼吸复合物中，而另一些则被输出到细胞质和其他细胞区室。整个系统受到严格监管。在本项目中，我们将从系统生物学的角度研究线粒体中的铁成分和铁相关过程，以获得对健康和疾病状态代谢的新见解。从酵母和人类细胞中分离和完整的线粒体将进行M“斯堡尔光谱，电子顺磁共振，电子吸收光谱和电感耦合等离子体发射质谱来评估细胞器的“铁组”。这种生物物理方法将用于研究从不同条件下生长的野生型酵母细胞（发酵与呼吸；缺铁与富铁）和不同遗传菌株中分离的线粒体。所研究的酵母菌株（在Yah1p、Atm1p、Mrs3p/4p和Mtm1p中缺失）已知会影响铁代谢，通常是通过导致铁在线粒体中积累。在人类中也有类似的情况，同源蛋白的缺陷导致铁的积累。将对积累的铁进行表征，并对其反应性进行研究。在线粒体中用于“运输”铁的低分子量单核非血红素复合物将通过色谱法分离，然后通过质谱法和核磁共振波谱法鉴定。这些复合物的代谢功能也将被研究。将人HL60细胞线粒体铁组与酵母线粒体铁组进行比较，并从铁线粒体生化和生理学的角度解释差异。该项目意义重大，因为将探索线粒体中与疾病相关的铁积累机制，并将分离和鉴定用于细胞运输的铁复合物。这类知识可能允许更好地控制进出细胞器的铁运输。这些铁复合物也可能在产生活性氧（ROS）中发挥作用，活性氧被认为是细胞损伤和衰老的某些方面的原因。公共卫生相关性：铁在细胞过程中极为重要；它以血红素群和铁硫团簇的形式存在。摄入的铁被包装起来，然后送到线粒体，一种细胞器，在那里它被转化成这些形式。包装材料的结构将被确定；这种结构可能“告诉”铁在细胞内的去向。将开发方法来检测从酵母和人类细胞分离的线粒体中所有不同形式的铁。在某些遗传状态下，铁聚集并可引起疾病；这种聚集的铁将被表征，试图消除它。

DESCRIPTION (provided by applicant): A significant portion of cellular iron metabolism occurs in the mitochondria, including iron import, iron-sulfur cluster assembly and heme biosynthesis. Some heme and iron-sulfur clusters are installed into respiratory complexes, while others are exported to the cytosol and other cellular compartments. The entire system is tightly regulated. In this project, iron components and iron-related processes in mitochondria will be investigated from a systems-biology perspective to gain new insights into the metabolism of healthy and diseased states. Isolated and intact mitochondria from yeast and human cells will be subjected to M"ssbauer spectroscopy, electron paramagnetic resonance, electronic absorption spectroscopy and inductively coupled plasma emission mass spectrometry to evaluate the "iron-ome" of the organelle. This biophysical approach will be used to study mitochondria isolated from wild-type yeast cells grown under different conditions (fermenting vs. respiring; Fe deficient vs. Fe replete) and from different genetic strains. The yeast strains to be investigated (depleted in Yah1p, Atm1p, Mrs3p/4p, and Mtm1p) are known to affect iron metabolism, generally by causing iron to accumulate in the mitochondria. There are analogous situations in humans, in which defects in homologous proteins result in iron accumulation. The accumulated iron will be characterized and its reactivity investigated. Low molecular weight mononuclear nonheme complexes that are used in "trafficking" iron in the mitochondria will be isolated by chromatography, and then identified by mass spectrometry and NMR spectroscopy. The metabolic function of these complexes will also be investigated. The iron-ome of mitochondria from human HL60 cells will be compared to that of yeast mitochondria and differences will be interpreted in terms of iron mitochondrial biochemistry and physiology. The project is significant because the mechanism of disease-related Fe accumulation in mitochondria will be explored and iron complexes that are used in cellular trafficking will be isolated and identified. Such knowledge may allow better control of iron trafficking into and out of the organelle. These iron complexes may also play a role in generating reactive oxygen species (ROS) which are thought to be responsible for some aspects of cellular damage and aging. PUBLIC HEALTH RELEVANCE: Iron is exceedingly important in cellular processes; it is found as heme groups and iron-sulfur clusters. Ingested iron is packaged and then sent to the mitochondria, a cellular organelle, where it is converted into these forms. The structure of the packaging material will be determined; this structure probably "tells" the iron where to go within the cell. Methods will be developed to detect all of the different forms of iron in mitochondria isolated from yeast and human cells. In some genetic states, iron aggregates and can cause disease; this aggregated iron will be characterized in an attempt to eliminate it.