Defining SaeR/S-dependent Neutrophil-S. aureus Interactions that Determine the Outcome of Infection

金黄色葡萄球菌(S.aureus)是美国最常见的细菌感染原因之一， 在医院和社区中对各种类型的感染负责，从轻微到致命不等 设置。在社区中，金黄色葡萄球菌通常会引起皮肤和软组织感染，估计有12- 每年门诊就诊人数为1300万人次(在美国)但也会导致严重的症状，包括坏死性 没有潜在风险的个体的筋膜炎和脓毒症。S。最具临床意义的方面之一。 金黄色葡萄球菌感染是金黄色葡萄球菌耐药的高流行率，是金黄色葡萄球菌发展的先天能力 对抗生素的耐药性使开发具有长期潜力的疗法变得非常困难 对金黄色葡萄球菌的疗效。本申请中提出的研究将拓宽我们对宿主的理解- 病原体的相互作用，为未来旨在新型智能设计的研究提供了基础 治疗细菌感染的疫苗和疗法。为此，这个项目将研究金黄色葡萄球菌如何利用 赛尔/S双组分基因调控系统逃避天然免疫。萨尔/S制度对 逃避中性粒细胞杀伤；然而，确切的机制依赖于Saer/S导致中性粒细胞 功能障碍没有定义。三个具体的目标将检验萨尔/S介导的向上- 金黄色葡萄球菌毒力基因的调节破坏了正常情况下会清除的有效的中性粒细胞反应 感染。在目标一中，通过rna-seq表达的宿主病原体rna将被用来确定直接的 SAER/S调控的细菌基因对人中性粒细胞基因表达的影响及解决 SAER/S组分同时对中性粒细胞和病原体基因表达的个体贡献。在……里面 目的二，研究Saer/S依赖的中性粒细胞人髓过氧化物酶的变化。 活性和产生的ROS改变中性粒细胞的凋亡和中性粒细胞 胞外陷阱(网)的形成。在第三个目标中，我们将利用一种新的体外中性粒细胞启动模型，通过 刺激PBMC确定SAER/S介导的初始免疫细胞相互作用对随后 中性粒细胞功能。这些体外原代人类细胞研究将与小鼠模型相辅相成 彻底评估这些免疫反应。本提案中概述的实验结果 将提高我们对宿主-病原体相互作用的整体理解，通过具体描述新的 SAER/S-金黄色葡萄球菌用来克服有效的中性粒细胞反应的机制。集体地 这项研究将解决我们的长期目标，即表征宿主之间的相互反应路径 和病原体，将突出病原体引起感染和宿主 解决疾病。研究结果将为疫苗和免疫治疗的发展提供有价值的信息。

Staphylococcus aureus (S. aureus) is one of the most frequent causes of bacterial infections in the U.S. and is responsible for diverse types of infections ranging in severity from mild to fatal in both hospital and community settings. In the community, S. aureus typically causes skin-and-soft-tissue infections with an estimated 12 – 13 million outpatient visits per-year (in the U.S.) but can also cause severe manifestations including necrotizing fasciitis and sepsis in individuals with no underlying risk. One of the most clinically significant aspects of S. aureus infections is the high prevalence of drug resistance and the innate ability for S. aureus to develop resistance to antibiotics making it very difficult to develop therapeutics that will have potential for long-term efficacy on S. aureus. The research proposed in this application will broaden our understanding of host- pathogen interactions, providing the foundation for future studies aimed at the intelligent design of novel vaccines and therapies to treat bacterial infection. To that end, this project will study how S. aureus uses the SaeR/S two-component gene regulatory system to evade innate immunity. The SaeR/S system is essential for evasion of neutrophil killing; however, exact mechanisms dependent on SaeR/S resulting in neutrophil dysfunction are not defined. Three specific Aims will test the hypothesis that the SaeR/S-mediated up- regulation of S. aureus virulence genes undermines an effective neutrophil response that would normally clear infection. In Aim One, host pathogen RNA expression via RNA-seq will be used to determine the direct influence of SaeR/S-regulated bacterial genes on human neutrophil gene expression as well as resolve the individual contribution of SaeR/S components on neutrophil and pathogen gene expression simultaneously. In Aim Two, we will determine how SaeR/S-dependent changes in neutrophil human myeloperoxidase (MPO) activity and the production reactive oxygen species (ROS) alters neutrophil apoptosis and neutrophil extracellular trap (NET) formation. In Aim Three, we will utilize a novel ex vivo model of neutrophil priming by stimulated PBMCs to determine the role of initial SaeR/S-mediated immune cell interactions on subsequent neutrophil function. These ex vivo primary human cell studies will be complemented with murine models of infection to thoroughly evaluate these immune responses. Findings from experiments outlined in this proposal will improve our overall understanding of host-pathogen interactions by specifically characterizing novel SaeR/S-mediated mechanisms used by S. aureus to overcome an effective neutrophil response. Collectively this research will address our long-term objective to characterize reciprocal response pathways between host and pathogen that will highlight key factors needed for both the pathogen to cause infection and for the host to resolve disease. Results will provide valuable information for vaccine and immunotherapeutic development.