Mitochondria as crucial regulators of innate immune outcomes during Mycobacterium tuberculosis infection

项目总结 我们对宿主线粒体健康和动态平衡如何调节的理解存在一个根本性的差距 传染病后果。本申请的总体目标是定义 病原体诱导的线粒体损伤和宿主线粒体突变对天然免疫结果的影响 结核分枝杆菌(Mtb)在体外巨噬细胞和人类疾病的小鼠模型中的感染。 由于线粒体起源于细菌祖先，它们释放了许多与损伤相关的分子。 细菌感染时激活先天免疫途径的凝集素模式(湿气)。尽管他们很清楚 调节先天免疫的潜力，线粒体抑制扭曲先天免疫反应的能力 在感染过程中仍未得到充分研究。有几条证据有力地证明了线粒体的动态平衡 对控制分枝杆菌感染结果至关重要。首先，全基因组关联研究频繁 确定线粒体相关基因(如LRRK2、TFAM、Polg)中的SNPs，使其对Myco-C易感 细菌感染。其次，分枝杆菌感染本身已被证明会破坏线粒体并释放 线粒体抑制与强大的先天免疫反应有关，包括I型干扰素。 抑制、炎性小体激活和炎性细胞死亡。此应用程序的中心假设是 结论：(1)结核分枝杆菌已经进化为直接损伤线粒体，以增强I型干扰素的表达和 诱导细菌前免疫重编程和(2)富亮氨酸重复序列蛋白2(LRRK2)启动子突变 分枝杆菌的易感性，因为它们损害了线粒体网络的稳定性，并引发了过量的细胞 感染结核分枝杆菌的巨噬细胞死亡，从而导致体内感染结核分枝杆菌时的过度炎症。要完全AP- 要了解线粒体-Mtb界面的生物学特性，需要同时考虑宿主和病原体。 为此，本提案的以病原体为重点的目标1旨在鉴定新的结核分枝杆菌毒力因子， 破坏线粒体内稳态，并将线粒体抑制物质的释放与I型干扰素的产生联系起来 结核杆菌感染的巨噬细胞。Aim 2将焦点转移到宿主上，并研究驱动 携带普通人的巨噬细胞的线粒体损伤和炎性细胞死亡途径 突变，Lrrk2G2019S。最后，目标3将把这些巨噬细胞表型与高炎症表型联系起来。 在感染Mtb的Lrrk2G2019S小鼠中进行观察，并确定药物治疗线粒体相关因子是否 LRRK2可以改变结核分枝杆菌感染的转归。这个项目意义重大，因为阐明了有丝分裂的作用- 干预性功能障碍在加剧肺结核疾病中的作用使治疗干预措施的设计成为可能 纠正线粒体缺陷，平衡扭曲的免疫反应，以改善患者的预后。这个AP- Proach具有创新性，因为它挑战了现有的概念范式，采用了复杂的技术 处于结核分枝杆菌研究的前沿，并利用寄主病原体两侧PI的独特专业知识 界面。

PROJECT SUMMARY There is a fundamental gap in our understanding of how host mitochondrial health and homeostasis modulate infectious disease outcomes. The overall objective of this application is to define the molecular contributions of pathogen-induced mitochondrial damage and host mitochondrial mutations to innate immune outcomes during Mycobacterium tuberculosis (Mtb) infection in macrophages ex vivo and in mouse models of human disease. Because mitochondria are of bacterial ancestral origin, they release many of the same damage-associated mo- lecular patterns (DAMPs) that activate innate immune pathways during bacterial infection. In spite of their clear potential to regulate innate immunity, the ability of mitochondrial DAMPs to skew innate immune responses during infection remains understudied. Several lines of evidence strongly argue that mitochondrial homeostasis is crucial for controlling mycobacterial infection outcomes. First, genome-wide association studies frequently identify SNPs in mitochondrial-associated genes (e.g. LRRK2, TFAM, POLG) that confer susceptibility to myco- bacterial infection. Second, mycobacterial infection itself has been shown to damage mitochondria and release mitochondrial DAMPs that are associated with potent innate immune responses, including type I interferon ex- pression, inflammasome activation, and inflammatory cell death. The central hypotheses of this application pre- dict that (1) Mtb has evolved to damage mitochondria directly in order to enhance type I IFN expression and induce pro-bacterial immune reprogramming and (2) mutations in leucine rich repeat kinase 2 (LRRK2) confer mycobacterial susceptibility because they compromise mitochondria network stability and trigger excessive cell death in Mtb-infected macrophages, which leads to hyperinflammation during Mtb infection in vivo. To fully ap- preciate the biology at the mitochondrial-Mtb interface, one needs to consider both the host and the pathogen. To this end, pathogen-focused Aim 1 of this proposal is designed to identify novel Mtb virulence factors that disrupt mitochondrial homeostasis and link the release of mitochondrial DAMPs to type I interferon production in Mtb-infected macrophages. Aim 2 shifts focus to the host and investigates the molecular mechanisms that drive mitochondrial damage and inflammatory cell death pathways in macrophages that harbor a common human mutation, Lrrk2G2019S. Lastly, Aim 3 will link these macrophage phenotypes to the hyperinflammatory phenotype observed in Mtb-infected Lrrk2G2019S mice and determine whether drugging mitochondrial-associated factors like LRRK2 can alter the outcome of Mtb infection. This project is significant because elucidating the role mitochon- drial dysfunction plays in exacerbating tuberculosis disease enables the design of therapeutic interventions that correct mitochondrial defects and balance skewed immune responses to improve patient outcomes. This ap- proach is innovative because it challenges existing conceptual paradigms, employs sophisticated technologies at the cutting-edge of Mtb research, and leverages the unique expertise of PIs on each side of the host-pathogen interface.