Neutrophil Accumulation in Bacterial Pneumonia

细菌性肺炎中的中性粒细胞积聚

• 批准号: 8830467
• 负责人: Samithamby Jeyaseelan
• 金额: $ 36.39万
• 依托单位: LOUISIANA STATE UNIV A&M COL BATON ROUGE
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2016-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8830467
• 关键词: Accounting; Acute; Acute Lung Injury; Acute respiratory infection; Address; Adoptive Transfer; Adult Respiratory Distress Syndrome; Affect; Age; Alveolar Macrophages; Anti-Inflammatory Agents; Anti-inflammatory; Antimicrobial Resistance; Attenuated; Bacteria; Bacterial Infections; Bacterial Pneumonia; Biological; Caspase-1; Cells; Chronic Obstructive Airway Disease; Cleaved cell; Community Hospitals; Data; Defense Mechanisms; Development; Equilibrium; Event; Family; Genes; Goals; Gram-Negative Bacteria; Health; Health Care Costs; Health Status; Host Defense; Host Defense Mechanism; Host resistance; Human; IL18 gene; Immune; Immune response; Immune system; In Vitro; Individual; Infection; Inflammatory; Inflammatory Response; Injury; Interleukin-1; Interleukin-17; Interleukin-18; Investigation; Klebsiella Infections; Klebsiella pneumonia bacterium; Knockout Mice; Laboratories; Lead; Lower Respiratory Tract Infection; Lower respiratory tract structure; Lung; Lung Inflammation; Lung diseases; Mediating; Mediator of activation protein; Modeling; Morbidity - disease rate; Multi-Drug Resistance; Mus; Myelogenous; Myeloid Cells; Natural Immunity; Neutrophil Infiltration; Organ; Pathway interactions; Phagocytosis; Play; Pneumonia; Population; Predisposition; Prevention strategy; Production; Proteins; Public Health; Recombinants; Recruitment Activity; Research; Respiratory System; Respiratory tract structure; Rest; Role; Signal Transduction; Small Interfering RNA; Staging; System; Systemic infection; Therapeutic Intervention; Tissues; bacterial resistance; burden of illness; cell type; cytokine; disability-adjusted life years; extracellular; global health; improved; in vivo; killings; macrophage; marenostrin; migration; mortality; neutrophil; novel; novel therapeutics; overexpression; pathogen; prevent; receptor; response; restoration; sensor; therapeutic target; toll-like receptor 4

DESCRIPTION (provided by applicant): Lung infections are a leading cause of morbidity, mortality and health care costs worldwide. Rapid clearance of pathogens from the respiratory tract is dependent on effective innate immune responses in the lung. Understanding the innate defense mechanisms in the lower respiratory tract is critical for the development of novel treatment and/or prevention strategies to reduce this burden of disease. The signaling cascades triggering innate immune responses consist of a delicate balance between pro- inflammatory responses that facilitate pathogen clearance, and counteracting anti-inflammatory responses that control excessive systemic inflammatory host responses. In general, it is poorly understood how these pathways converge to regulate host defense while minimizing inflammatory tissue injury. The long-term goal of this research is to understand how multiple innate immune events are integrated into effective antimicrobial resistance. As a model to elucidate the basic host defense mechanisms, we have focused on a primary pathogen, Klebsiella pneumoniae because this extracellular Gram-negative bacterium causes severe pneumonia; and the extensive spread of multiple drug-resistant K. pneumoniae strains worldwide. Although K. pneumoniae signals via Toll-like receptor (TLR)-4 and 9, a few studies have also indicated the involvement of NOD-like receptors (NLRs) as cytosolic immune sensors. Some NLRs termed "inflammasomes" can activate caspase-1 in order to cleave IL-1¿ and IL-18. We have previously shown the NLR family CARD domain containing 4 (NLRC4; IPAF) as a new sensor to K. pneumoniae in human and mouse macrophages that regulates caspase-1 dependent maturation of the inflammatory cytokines, IL1¿ and IL18. IL-1R1 knockout (KO) mice show greater susceptibility than NLRC4 KO mice to intrapulmonary K. pneumoniae infection, suggesting the involvement of other more prominent NLR proteins. Our preliminary data demonstrate that (1) human lungs with bacterial pneumonia show higher expression of NLR family pyrin domain containing 6 (NLRP6) inflammasome; (2) neutrophils show the highest expression of NLRP6 during resting stage and upon bacterial infection; (3) as compared with other NLRs (NOD1, NOD2, NLRP3 and NLRC4), NLRP6 is most prominent for bacterial clearance in the lungs during Klebsiella pneumonia; (4) neutrophils produce IL-17A and IL-17F in the lungs during bacterial pneumonia; and (5) NLRP6 knockdown human alveolar macrophages produce attenuated levels of IL-1¿ and IL-18 proteins following K. pneumoniae LPS challenge. Our key findings support a critical yet unrecognized function for NLRP6 during Klebsiella infection. This renewal proposal seeks to address the central hypothesis that NLRP6 is a key mediator of host defense during gram-negative bacterial pneumonia via induction of IL-17; thus, NLRP6 is a potential therapeutic target that could augment host defenses to acute respiratory infections. The Aims are: (1) Determine the effects of NLRP6 on bacterial clearance and neutrophil function following K. pneumoniae challenge.; (2) Determine the effects of NLRP6-dependent IL-17 production on host resistance to bacterial pneumonia.; (3) Identify functional alterations in alveolar macrophages caused by NLRP6 disruption with bacterial pneumonia.; and (4) Explore if manipulation of NLRP6 signaling can augment host resistance during Klebsiella pneumonia. A unique combination of in vivo and in vitro systems, including conditional KO mice, lentiviral transduction, adoptive transfer, and cytokine restoration strategies will be employed to address these Aims. Proving that the specific inflammasome plays a critical role in lung inflammation and host defense will lead to a major paradigm shift and ultimately lead to new therapeutic and prevention strategies of the treatment of ALI and ARDS in bacterial pneumonia because prior studies of the role of NLRs and other cytosolic sensors have been exclusively confined to in vitro studies and systemic Infection models.

描述（由适用提供）：肺部感染是全球发病率，死亡率和医疗保健成本的主要原因。从呼吸道中快速清除病原体取决于肺中有效的先天免疫回报。了解下呼吸道中的先天防御机制对于减少这种疾病燃烧的新型治疗和/或预防策略至关重要。信号级联触发先天免疫反应的级联反应包括促进炎症反应之间的微妙平衡，促进病原体清除率，并抵消控制过多的全身炎症宿主反应的抗炎反应。通常，鲜为人知的是，这些途径如何融合以调节宿主防御，同时最大程度地减少炎症组织损伤。这项研究的长期目标是了解如何将多个先天免疫事件整合到有效的抗菌抗性中。作为阐明基本宿主防御机制的模型，我们专注于原发性病原体Klebsiella肺炎，因为这种细胞外革兰氏阴性细菌会导致严重的肺炎。以及全球多种耐药性肺炎菌株的广泛传播。尽管K.肺炎通过Toll样受体（TLR）-4和9信号，但一些研究也表明NOD样受体（NLR）作为胞质免疫传感器。一些称为“炎症”的NLR可以激活caspase-1，以清除IL-1和IL-18。我们先前已经显示了包含4个（NLRC4; ipaf）的NLR家族卡结构域，作为人和小鼠巨噬细胞中肺炎的新传感器，可调节炎症细胞因子，IL1€和IL18的caspase-1依赖性成熟。 IL-1R1基因敲除（KO）小鼠比NLRC4 KO小鼠对肺内肺炎的肺炎感染的敏感性更大，这表明其他更突出的NLR蛋白的参与。我们的初步数据表明，（1）肺炎细菌的人肺表现出含有6（NLRP6）炎症体的NLR家族pyrin结构域的较高表达； （2）中性粒细胞在静止阶段和细菌感染期间表现出最高的NLRP6表达； （3）与其他NLR（NOD1，NOD2，NLRP3和NLRC4）相比，NLRP6在肺炎克雷伯氏菌期间最突出的细菌清除率最为突出； （4）肺炎细菌期间肺中性粒细胞在肺部产生IL-17A和IL-17F； （5）NLRP6敲低的人肺泡巨噬细胞在K.肺炎LPS挑战时产生了衰减的IL-1和IL-18蛋白水平。我们的主要发现支持克雷伯菌感染期间NLRP6的关键但无法识别的功能。该更新提案旨在解决中心假设，即NLRP6是通过诱导IL-17诱导革兰氏阴性细菌期间宿主防御的关键介体。因此，NLRP6是一个潜在的治疗靶标，可以将宿主防御力增强到急性呼吸道感染。目的是：（1）确定K.肺炎挑战后NLRP6对细菌清除和中性粒细胞功能的影响。 （2）确定NLRP6依赖性IL-17产生对宿主对肺炎细菌的抗性的影响。 （3）确定由肺炎细菌造成的NLRP6破坏引起的肺泡巨噬细胞的功能改变。 （4）探索在克雷伯氏菌肺炎期间对NLRP6信号的操纵是否会增强宿主的耐药性。体内和体外系统的独特组合将采用有条件的KO小鼠，慢病毒转移，自适应转移和细胞因子恢复策略来解决这些目标。证明特定的炎症体在肺部感染和宿主防御中起着至关重要的作用，将导致重大的范式转移，并最终导致新的治疗和预防策略在细菌肺炎中治疗Ali和ARDS的治疗策略，因为先前研究NLRS和其他细胞粘膜传感器的作用和其他细胞质传感器的作用已被排他性地限制在综合研究和系统中。