Mitochondrial Calcium Signaling in Cell Intrinsic Immunity

项目总结 免疫系统的吞噬细胞需要迅速爆发的能量来吞噬细胞并及时杀死病原体 举止。需要能量的大分子复合体，如液泡ATPase(V-ATPase)和NADPH 氧化酶(NOX)复合体被招募到吞噬小体中，以酸化、氧化、杀死和消化致病物质。 基因表达对新陈代谢机制的重新编程太慢了，不能满足急剧增长的需求 能量和代谢物。前哨吞噬细胞如何传递对病原体的识别以切换 细胞新陈代谢的主要齿轮如此之快？我们的初步数据表明，钙离子选择性， 线粒体离子通道，MCU，在快速连接感觉的信号回路中起着关键作用 病原体对吞噬小体杀灭所必需的代谢产物的受体。追寻这些诱人的线索 现在已经为假设吞噬小体-线粒体的组装接近奠定了坚实的科学基础 结构(PMPA)和线粒体钙信号促进细胞内源性免疫。在Aim1中，我们定义 白念珠菌引发线粒体-吞噬小体相互作用的机制。在目标2中，我们定义了 激活的巨噬细胞中钙离子信号的调节机制。在目标3中，我们定义了关键 线粒体钙的代谢输出--驱动微生物死亡的信号。这项研究在概念上是创新的，因为 它揭示了病原体线粒体生理学、免疫代谢和 微生物杀戮。创新包括监测执行初级巨噬细胞的mCa~(2+)升高的工具 基于吞噬作用和电子断层扫描的线粒体-吞噬小体相互作用的三维重建。这个 研究有可能揭示对其他特殊吞噬过程具有显著意义的设计原理 例如清除凋亡细胞、有毒碎片和突触修剪。从翻译/临床前的角度来看， 我们的发现可能为新的免疫调节疗法揭示新的分子靶点和途径。

PROJECT SUMMARY The phagocytes of the immune system require a rapid burst of energy to phagocytose and kill pathogens in a timely manner. Energy demanding macromolecular complexes such as vacuolar ATPase (V-ATPase) and NADPH oxidase (NOX) complexes are recruited to the phagosome to acidify, oxidize, kill, and digest the pathogenic cargo. Reprogramming of the metabolic machinery by gene expression is too slow to meet the sharply increased demand for energy and metabolites. How do the sentinel phagocytes transmit the recognition of pathogens to switch the primary gears of cellular metabolism so rapidly? Our preliminary data indicated that the Ca2+-selective, mitochondrial ion channel, MCU, plays a crucial role in the signaling circuits that rapidly connect the sensory receptors of pathogens to the metabolic outputs necessary for phagosomal killing. Pursuing these tantalizing leads has now laid a strong scientific foundation to hypothesize that assembly of phagosome-mitochondria proximity architecture (PMPA) and mitochondrial Ca2+-signaling fuels cell-intrinsic immunity. In Aim1, we define the mechanisms underlying mitochondria-phagosome interactions triggered by C. albicans. In Aim 2, we define mechanisms through which mCa2+-signaling is regulated in activated macrophages. In Aim 3, we define the key metabolic outputs of mCa2+-signaling that drive microbial killing. This research is conceptually innovative because it unravels fascinating new connections between pathogen mitochondrial physiology, immunometabolism and microbial killing. Innovations include tools to monitor mCa2+-elevations in primary macrophages executing phagocytosis and Electron Tomography based 3D reconstructions of Mitochondria-Phagosome interactions. The research has the potential to reveal design principles that are of salience to other specialized phagocytic processes such as clearance of apoptotic cells, toxic debris, and synaptic pruning. From a translational/preclinical perspective, our findings may reveal novel molecular targets and pathways for new immunomodulatory therapies.