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

定义 SaeR/S 依赖性中性粒细胞-S。

• 批准号: 10194360
• 负责人: Tyler K Nygaard
• 金额: $ 60.9万
• 依托单位: MONTANA STATE UNIVERSITY - BOZEMAN
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-16 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10194360
• 关键词: Address; Antibiotic Resistance; Antibiotics; Apoptosis; Autophagocytosis; Bacterial Genes; Bacterial Infections; Cell Communication; Cell Culture System; Cell Culture Techniques; Cells; Communities; Complement; Cytolysis; Data; Development; Disease; Drug resistance; Effectiveness; Environment; Event; Foundations; Functional disorder; Future; Gene Expression; Genes; Genetic Transcription; High Prevalence; Hospitals; Human; Immune; Immune response; Immunotherapeutic agent; Individual; Infection; Inflammation Mediators; Intelligence; Life; Link; Mediating; Methods; Modeling; Molecular; Morbidity - disease rate; Natural Immunity; Necrotizing fasciitis; Neutrophil Infiltration; Outcome; Outpatients; Pathogenesis; Pathway interactions; Peripheral Blood Mononuclear Cell; Peroxidases; Phagocytosis; Play; Population; Production; Public Health; Publishing; RNA; Reactive Oxygen Species; Regulation; Regulator Genes; Reporting; Research; Resistance development; Risk; Role; Sepsis; Severities; Signal Transduction; Skin; Soft Tissue Infections; Staphylococcus aureus; Staphylococcus aureus infection; System; TNF gene; Testing; Therapeutic; Time; Transcript; Up-Regulation; Vaccines; Virulence; Visit; antimicrobial; base; clinically significant; combat; community setting; design; emerging pathogen; experimental study; extracellular; improved; in vivo; leukotoxin; monocyte; mortality; mouse model; neutrophil; next generation sequencing; novel; novel therapeutics; novel vaccines; pathogen; prevent; response; sensory system; skin abscess; transcriptome; transcriptome sequencing

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.

金黄色葡萄球菌 (S. aureus) 是美国细菌感染最常见的原因之一， 在医院和社区造成多种类型的感染，严重程度从轻微到致命 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 – 每年门诊量达 1300 万人次（在美国），但也可能导致严重的症状，包括坏死 无潜在风险的个体发生筋膜炎和败血症。 S. 最具临床意义的方面之一。 金黄色葡萄球菌感染是耐药性的高发生率和金黄色葡萄球菌天生的发展能力 对抗生素的耐药性使得开发具有长期潜力的治疗方法变得非常困难 对金黄色葡萄球菌的功效。本申请中提出的研究将拓宽我们对宿主的理解 病原体相互作用，为未来旨在智能设计新型病原体的研究奠定了基础 治疗细菌感染的疫苗和疗法。为此，该项目将研究金黄色葡萄球菌如何利用 SaeR/S 双组分基因调控系统可逃避先天免疫。 SaeR/S 系统对于 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。三个具体目标将检验 SaeR/S 介导的上行假设 金黄色葡萄球菌毒力基因的调节破坏了通常会清除的有效中性粒细胞反应 感染。在目标一中，通过 RNA-seq 的宿主病原体 RNA 表达将用于确定直接 SaeR/S 调节的细菌基因对人中性粒细胞基因表达的影响，并解决了 SaeR/S 成分同时对中性粒细胞和病原体基因表达的个体贡献。在 目标二，我们将确定中性粒细胞人髓过氧化物酶 (MPO) 中 SaeR/S 依赖性变化如何 活性氧 (ROS) 的活性和产生改变中性粒细胞凋亡和中性粒细胞 细胞外陷阱（NET）的形成。在目标三中，我们将利用一种新型的中性粒细胞启动离体模型 刺激 PBMC 以确定初始 SaeR/S 介导的免疫细胞相互作用对后续的作用 中性粒细胞功能。这些离体原代人类细胞研究将得到小鼠模型的补充 感染以彻底评估这些免疫反应。本提案中概述的实验结果 通过具体描述新的特征，将提高我们对宿主与病原体相互作用的整体理解 金黄色葡萄球菌使用 SaeR/S 介导的机制来克服有效的中性粒细胞反应。集体 这项研究将解决我们的长期目标，即描述宿主之间的相互反应途径 和病原体，将突出病原体引起感染和宿主感染所需的关键因素 解决疾病。结果将为疫苗和免疫治疗的开发提供有价值的信息。