Human neutrophils and Staphylcoccus aureus: microbial targets and responses

人类中性粒细胞和金黄色葡萄球菌：微生物靶标和反应

• 批准号: 8762232
• 负责人: William M. Nauseef
• 金额: --
• 依托单位: IOWA CITY VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8762232
• 关键词: Abscess; Address; Agonist; Antibiotic Resistance; Antibiotics; Apoptosis; Apoptotic; Biological Models; Biology; Cells; Chronic; Clinical; Collection; Complex; Cytoplasmic Granules; Data; Development; Disease; Disease Progression; Elements; Equus caballus; Experimental Models; Failure; Genus staphylococcus; Growth; Healthcare Systems; Host Defense; Human; IL8 gene; Immune; Immune system; In Vitro; Infection; Infection Control; Inflammation; Inflammatory Response; Ingestion; Institution; Interleukin-1; Interleukin-6; Mediating; Medical center; Microbe; Modeling; Molecular; Morbidity - disease rate; Mus; NADPH Oxidase; Necrosis; Neoplasm Metastasis; Organism; Outcome; Outpatients; Oxidants; Oxidases; Pathogenesis; Patients; Phagocytes; Phagocytosis; Phagosomes; Phase; Phospholipase C; Prevalence; Prevalence Study; Production; Recruitment Activity; Relapse; Relative (related person); Resolution; Staging; Staphylococcal Infections; Staphylococcus aureus; Surveys; System; Testing; Therapeutic; Toxin; Translating; Veterans; Virulence Factors; Work; aged; analytical tool; antimicrobial; base; cytokine; extracellular; human disease; immunogenic; in vitro Model; in vivo; insight; killings; macrophage; microbial; mortality; neutrophil; novel; novel therapeutics; programs; public health relevance; response; targeted treatment; tool; uptake

DESCRIPTION (provided by applicant): Infection with Staphylococcus aureus (SA) remains an important clinical challenge despite potent antibiotics. Novel therapeutic advances await elucidation of the molecular bases for persistence, chronicity, and metastatic spread - i.e. the hallmarks of SA infection. The remarkable proclivity of SA to produce severe and chronic human disease reflects, in part, the array of virulence factors it expresses, including a phosphoinositol-specific phospholipase C (PI-PLC) that is secreted during its late logarithmic growth phase. PI-PLC is secreted during infection and is immunogenic, making it a candidate as a virulence factor. Human polymorphonuclear leukocytes (PMN) are at the front-line of cellular innate immune-mediated host defense against SA infection, and PMN exert ~ all of their antimicrobial effort against SA internalized within phagosomes. During PMN phagocytosis and coincident with activation of the phagocyte NADPH oxidase, granules fuse with nascent phagosomes and release their contents into the phagosome, thereby exposing the ingested microbe to an array of toxic agents and a flux of oxidants that collaborate to kill microbes in phagosomes. However, despite the presence of this potent PMN antimicrobial system, 10-20% of ingested SA remain viable, but not replicating, in PMN. In response to PMN toxins in phagosomes, persisting viable SA stimulate PMN to initiate transcriptional programs that dictate the fate of PMN. SA-laden PMN have two potential fates: they may progress from atypical apoptosis to necrosis, with release of viable SA, or can be ingested by macrophages (Mf), thereby triggering phenotypic responses that promote further inflammation. Whereas Mf uptake of typical apoptotic PMN occurs without triggering proinflammatory cascades (i.e. a non phlogistic response), we have recently demonstrated that Mf ingestion of SA-PMN promoted aberrant cytokine responses. Persistence of SA within phagocytes has profound clinical consequences, as signature features of SA infection are relapse, metastases, and failure of antibiotics to which SA are susceptible. In murine infection models, PMN-associated SA recovered from an abscess can transmit infection to na¿ve mice, demonstrating that PMN can serve as a "Trojan horse", covertly entering macrophages (Mf) and then disseminating to cause metastatic infection. Given our preliminary data, we propose studies to test the overall hypothesis that SA PI-PLC serves as a virulence factor for SA by virtue of its ability to undermine phagocyte innate host defense. We hypothesize that PI-PLC may contribute to SA infection at two distinct stages: (1) early in infection, before effective cellular host defenses have been engaged and organisms ingested, extracellular PI-PLC will attack vulnerable substrates, including those on recruited phagocytes, and undermine their capacity to respond normally (Aim 1); and (2) later, after ingestion by phagocytes PI-PLC-expressing SA within phagosomes will alter PMN-Mf interactions, interfere with normal resolution of inflammation, and promote infection and dissemination (Aim 2). Our Specific Aims include: Aim 1. To determine the impact of extracellular SA PI-PLC on phagocyte function and innate host defense - focusing on priming of PMN NADPH oxidase and direct agonist effects phagocytes, and Aim 2. To determine the contribution of PI-PLC expressed within PMN on initiation and promotion of SA infection - focusing on PMN and Mf fate in vitro and consequences in infection in vivo. We have generated the analytical tools and developed experimental models necessary to study the effects of PI-PLC on phagocyte responses, and our ongoing studies of interactions between PMN containing viable SA and Mf provide a framework to model in vitro the fate of SA-laden PMN as might occur in infection.

描述（由申请人提供）： 金黄色葡萄球菌（SA）感染仍然是重要的临床挑战目的地潜在的抗生素。新的治疗进展正在等待分子碱基的持久性，慢性和转移扩散 - 即SA感染的标志。 SA产生严重和慢性人类疾病的显着倾向反映了它表达的一系列病毒因素，包括在其晚期对数生长阶段分泌的磷酸肌醇特异性磷脂酶C（PI-PLC）。 PI-PLC在感染期间分泌，具有免疫原性，使其成为候选病毒因子。人类多形核白细胞（PMN）处于细胞先天免疫介导的宿主防御SA感染的前线，PMN施加〜对SA在吞噬体内内化的所有抗菌作用。在PMN吞噬作用和激活吞噬细胞氧化物的激活期间，颗粒与新生的吞噬体融合并将其含量释放到吞噬体中，从而将摄入的微生物暴露于一系列有毒药物和氧化剂的氧化剂和氧化剂中，以合作杀死鼠类中的微生物中的微生物中的微生物。但是，在PMN中，有10-20％的摄入的SA摄入的SA仍然可以生存但不复制。为了响应吞噬体中的PMN毒素，持续存在的SA刺激PMN启动转录程序决定了PMN的命运。含SA的PMN有两个潜在的命运：它们可能从非典型凋亡到坏死，释放可行的SA，或者可以被巨噬细胞（MF）摄入，从而触发表型反应，从而促进进一步的感染。尽管MF摄入典型的凋亡PMN发生而不会触发促炎的级联反应（即非Phlogistic反应），但我们最近证明，SA-PMN的MF摄入促进了异常的细胞因子反应。吞噬细胞中SA的持久性具有深远的临床后果，因为SA感染的签名特征是SA易感的抗生素的缓解，转移和抗生素失败。在鼠感染模型中，从脓肿中恢复的与PMN相关的SA可以将感染传播到Na�Ve小鼠，表明PMN可以用作“特洛伊木马”，掩盖进入巨噬细胞（MF），然后发散以引起转移性感染。鉴于我们的初步数据，我们提出了研究，以检验SA PI-PLC的总体假设，即SA PI-PLC是SA的病毒因素，因为它可以破坏吞噬细胞先天的宿主防御。我们假设PI-PLC可能会在两个不同的阶段导致SA感染：（1）感染的早期，在有效的细胞宿主防御剂已参与之前，组织摄入的组织，细胞外PI-PLC将攻击脆弱的底物，包括在招募的吞噬细胞上，并使他们的能力响应响应正常（AIM 1）； （2）稍后，在吞噬体内表达PI-PLC的SA摄入吞噬体将改变PMN-MF相互作用，干扰正常的感染分辨率，并促进感染和传播（AIM 2）。我们的具体目的包括：目标1。确定细胞外SA PI -PLC对吞噬细胞功能和先天宿主防御的影响 - 重点是启动PMN NADPH氧化物和直接的激动剂效应吞噬细胞，并旨在确定PMN在PMN中表达的PI -PLC对SA的贡献对SA的贡献对SA的启动和促进对PMN和MFATO的促进，从而在PMN和Mfate In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In Intros发出注入。我们已经生成了分析工具，并开发了研究PI-PLC对吞噬细胞反应的影响所需的实验模型，并且我们对含有可行SA和MF的PMN相互作用的持续研究提供了一个框架，可以在体外模拟SA-LADENPMN的命运。