Mechanisms of host protection against pathogen-associated proteases in acute lung injury

急性肺损伤中宿主针对病原体相关蛋白酶的保护机制

• 批准号: 10231500
• 负责人: Janet Sojung Lee
• 金额: $ 57.42万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10231500
• 关键词: Acute Lung Injury; Admission activity; Adult Respiratory Distress Syndrome; Alpha Granule; Alveolar; Bacteria; Bacterial Infections; Bacterial Pneumonia; Biology; Blood Platelets; Blood capillaries; Cathepsins; Cell Survival; Cells; Cleaved cell; Clinical; Critical Care; Data; Elastases; Environment; Epithelial Cells; Exhibits; Extracellular Matrix; Goals; Host Defense; Human; Infection; Inflammation; Inflammatory; Inflammatory Response; Injury; Integration Host Factors; Knockout Mice; Leukocyte Elastase; Lower respiratory tract structure; Lung; Lung Inflammation; Lung infections; Mediating; Metalloproteases; Modeling; Molecular; Morbidity - disease rate; Mus; Mutation; N-terminal; Neutrophil Activation; Outcome; Pathogenicity; Pathway interactions; Patients; Peptide Hydrolases; Platelet Activation; Positioning Attribute; Predisposition; Production; Property; Proteins; Proteolysis; Proteolytic Processing; Pseudomonas; Pseudomonas aeruginosa; Pseudomonas aeruginosa infection; Publishing; RNA Interference; Reporter; Respiratory Failure; Respiratory Tract Infections; Role; Serine Protease; Site; Source; Structure of parenchyma of lung; System; Thrombospondin 1; Translating; Type II Secretion System Pathway; Virulence; Virus; Work; antimicrobial drug; base; conditional knockout; cytokine; design; extracellular; fungus; improved; in vivo; indexing; inhibitor/antagonist; intravital microscopy; lung injury; mortality; neutralizing antibody; neutrophil; pathogen; repaired; resilience; respiratory; response; targeted treatment; tissue injury

Project Summary/Abstract: The broad, long term objective is to identify host-protective mechanisms that counter pathogen-initiated lung inflammation and injury. Many pathogens secrete proteases to cause direct damage to the lung, but bacteria, fungi and viruses can also co-opt host proteases to increase pathogenicity and promote lung injury. We have studied Pseudomonas aeruginosa (PA) as a model of infection-induced injury to probe how a pathogen-encoded protease called Pseudomonas elastase LasB, a metalloprotease released into the extracellular milieu by the PA type II secretion system, induces lung tissue damage and secondary trigger of host-derived serine proteases such as neutrophil elastase (NE). We previously identified thrombospondin-1 (TSP-1), a matricellular protein secreted by a variety of cells following injury that disarms both pathogen-encoded LasB and host protease NE, to limit lung injury and inflammation. Key questions that have arisen from this work is how an unregulated proteolytic environment drives excessive inflammatory response and dysregulated repair following injury, and what are the host factors that calibrate this response in the lung. Our preliminary findings suggest that a feed-forward neutrophilic inflammatory response occurs in the proteolytic environment of PA infection through N-terminal processing of IL-36γ that is exaggerated in the absence of TSP-1. Moreover, platelet TSP-1 appears protective against PA-induced lung injury, but the precise mechanism related to TSP-1's role at the alveolar-capillary interface remains unknown. Furthermore, we show that PA elastase activity in clinical strains confer excessive inflammation and injury in mice and is associated with worse clinical outcomes when compared with non-elastase producers. Based upon these findings, we propose the following aims utilizing genetically deficient mice, cell-specific conditional knockout systems, and PA clinical respiratory isolates obtained from the ICU to (1) elucidate the mechanisms by which TSP-1 counters the hyperinflammatory response mediated by proteolytic processing of the pro-inflammatory cytokine IL-36γ; (2) examine the contribution of TSP-1 and platelet TSP-1 in protection against alveolar barrier disruption and stabilization of the early provisional matrix following lung injury; (3) determine whether PA ICU respiratory isolates with elastolytic properties drive unwarranted inflammation and persistent tissue injury in the susceptible host. A better understanding of host biology during severe respiratory infection could prove useful in the rational design of targeted therapeutics against pathogen-derived proteases and deregulated host inflammation as adjuncts to current antimicrobial agents and supportive pulmonary and critical care management.

项目摘要/摘要：广泛的长期目标是确定宿主保护机制 反病原体引起的肺部感染和损伤。许多病原体秘密蛋白酶引起直接的 对肺的损害，但是细菌，真菌和病毒也可以选择宿主蛋白酶以增加致病性 并促进肺损伤。我们已经研究了铜绿假单胞菌（PA）作为感染诱导的模型 探测病原体编码的蛋白酶如何称为假单胞菌弹性酶LASB的伤害，金属蛋白酶 PA II型分泌系统释放到细胞外环境中，诱导肺组织损伤和 宿主衍生的序列蛋白酶（如中性粒细胞弹性酶（NE））的次要触发因素。我们以前已经确定 血小板传播-1（TSP-1），一种由多种细胞分泌的基质蛋白，损伤后多种细胞 病原体编码的LASB和宿主蛋白酶NE，以限制肺损伤和注射。关键问题 这项工作产生的是不受管制的蛋白水解环境如何驱动过量的炎症 受伤后的响应和不调节修复失调，在校准此反应的宿主因素是什么 肺。我们的初步发现表明，在 PA感染的蛋白水解环境通过IL-36γ的N末端加工而被夸大 缺乏TSP-1。此外，血小板TSP-1似乎可以防止PA诱导的肺损伤，但精度 与TSP-1在肺泡毛细血管界面上的作用有关的机制仍然未知。此外，我们显示 临床菌株中PA弹性酶的活性会议会议过度炎症和小鼠损伤，并且相关 与非弹性酶生产者相比，临床结果较差。根据这些发现，我们 提案以下目的是利用普遍缺陷的小鼠，特定于细胞的条件敲除系统和 PA从ICU获得的PA临床呼吸系统株（1）阐明了TSP-1的机制 反理通过促炎细胞因子的蛋白水解加工介导的高炎症反应 IL-36γ; （2）检查TSP-1和血小板TSP-1在保护肺泡屏障中的贡献 肺损伤后早期临时基质的破坏和稳定； （3）确定PA ICU是否 具有弹性特性的呼吸隔离株驱动着不必要的注射和持续的组织损伤 敏感的主人。对严重呼吸道感染期间宿主生物学的更好理解可能会被证明有用 在针对病原体衍生蛋白酶和放松宿主的有针对性治疗的合理设计中 炎症是当前抗菌剂的辅助以及支持性肺和重症监护的炎症 管理。