The immunometabolite itaconate drives S. aureus lung infection

项目总结/摘要 金黄色葡萄球菌导致社区获得性肺炎和医疗保健相关肺炎， 肺功能和死亡风险增加，特别是在已有肺部疾病的患者中。这些 感染很难根除，因为S.金黄色葡萄球菌可以转变为适应性表型， 和生物膜，其保护细菌免受宿主吞噬细胞和抗微生物因子以及抗生素的侵害。 宿主对病原体的免疫反应的一个关键组成部分是产生调节代谢物， 衣康酸，它在免疫细胞中由酶免疫应答基因1（Irg 1）合成。衣康 平衡宿主免疫细胞中的促炎和抗炎信号传导，并对细菌施加代谢压力。我们 最近证明衣康酸盐抑制S.金黄色葡萄球菌糖酵解和重组葡萄球菌代谢 以促进生物膜形成。衣康酸还限制了关键能量产生途径的使用，这表明， 它可以促进耐缺氧持续细胞的形成。衣康酸在驱动S.金黄色肺 如果不研究其对宿主对S. 金黄色。初步数据表明，Irg 1在中性粒细胞中高度表达，并与 在S.金黄色葡萄球菌肺部感染，这不同于抗- 在其他细胞类型和感染模型中已经定义了衣康酸盐的炎症作用。 本研究旨在进一步研究衣康酸作为宿主-病原体动态的中心介质 在S.金黄色葡萄球菌肺部感染和S.金黄色葡萄球菌适应肺部。目标1将定义 衣康酸在调节宿主对S.利用代谢组学、吞噬作用 测定、氧化爆发测定和scRNA测序，以1）确定嗜中性粒细胞是否是肿瘤的主要来源， 衣康酸在S.金黄色葡萄球菌感染，2）确定衣康酸盐对中性粒细胞效应子功能的影响，以及3） 鉴定嗜中性粒细胞和其他免疫细胞中衣康酸盐差异调节的途径 在体内感染期间的种群。目的2将定义衣康酸在驱动S.金黄色葡萄球菌适应 通过使用细菌qRT-PCR、ATP定量、抗生素耐受性测定和流式细胞术对1） 确定衣康酸盐是否驱动促进体内持久细胞形成的转录变化，2）建立 衣康酸盐暴露驱动能量代谢降低和离体抗生素耐受性增加，以及3） 量化S。金黄色葡萄球菌分裂和生长对体内衣康酸盐的反应。这些研究将共同定义 宿主免疫代谢在S.金黄色葡萄球菌肺部感染

PROJECT SUMMARY/ABSTRACT Staphylococcus aureus causes community-acquired and healthcare-associated pneumonias that drive a decline in lung function and an increased risk of mortality, especially in patients with preexisting lung disease. These infections are difficult to eradicate because S. aureus can transition to adaptive phenotypes like persister cells and biofilm, which protect the bacteria against host phagocytes and antimicrobial factors, as well as antibiotics. A key component of the host immune response to pathogens is the production of regulatory metabolites like itaconate, which is synthesized in immune cells by the enzyme Immune-Responsive Gene 1 (Irg1). Itaconate balances pro- and anti-inflammatory signaling in host immune cells and exerts metabolic stress on bacteria. We recently demonstrated that itaconate inhibits S. aureus glycolysis and restructures staphylococcal metabolism to promote biofilm formation. Itaconate also limited the use of key energy-producing pathways, suggesting that it may promote the formation of antibiotic-tolerant persister cells. The role of itaconate in driving S. aureus lung infections cannot be completely understood without also investigating its impact on the host response to S. aureus. Preliminary data demonstrate that Irg1 is highly expressed in neutrophils and is associated with increased pro-inflammatory cytokine production during S. aureus lung infection, which differs from the anti- inflammatory effects of itaconate that have been defined in other cell types and infection models. This proposal aims to further investigate itaconate as a central mediator of the host-pathogen dynamic during S. aureus lung infection and a potential driver of S. aureus adaptation to the lung. Aim 1 will define the role of itaconate in regulating the host immune response to S. aureus by using metabolomics, phagocytosis assays, oxidative burst assays, and scRNA-sequencing to 1) determine if neutrophils are a major source of itaconate during S. aureus infection, 2) define the impact of itaconate on neutrophil effector function, and 3) identify the pathways that are differentially regulated by itaconate in neutrophils and other immune cell populations during in vivo infection. Aim 2 will define the role of itaconate in driving S. aureus adaptation to the lung by using bacterial qRT-PCR, ATP quantification, antibiotic tolerance assays, and flow cytometry to 1) determine if itaconate drives transcriptional changes that promote persister cell formation in vivo, 2) establish that itaconate exposure drives reduced energy metabolism and increased antibiotic tolerance ex vivo, and 3) quantify S. aureus division and growth in response to itaconate in vivo. Together, these studies will define the role of host immunometabolism in driving inflammation and bacterial persistence during S. aureus lung infection.