Mechanisms of PVL-induced Acute Lung Injury

PVL引起的急性肺损伤的机制

• 批准号: 8277422
• 负责人: Binh An Diep
• 金额: $ 42.83万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-15 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8277422
• 关键词: Accounting; Active Immunization; Acute; Acute Lung Injury; Alveolar; Antibodies; Attenuated; Cells; Cessation of life; Chemotactic Factors; Communities; Complement; Conflict (Psychology); Cytolysis; Cytoplasmic Granules; Data; Development; Disease; Epidemic; Exotoxins; FOLH1 gene; Genes; Hemolysin; Human; Immunity; Individual; Infection; Inflammation; Inflammatory Response; Injury; Interleukin-8; Knowledge; Leucocidin; Lung; Lung Inflammation; Measures; Mediating; Modeling; Mus; Necrosis; Oryctolagus cuniculus; Panton-Valentine leukocidin; Parents; Passive Immunization; Pathogenesis; Patients; Permeability; Pharmaceutical Preparations; Phenols; Play; Pneumonia; Predisposition; Prevention approach; Process; Prophylactic treatment; Pulmonary Edema; Recruitment Activity; Relative (related person); Rodent; Role; Staphylococcus aureus; Testing; Therapeutic Intervention; Time; Tissues; Toxin; Virulence; Virulent; base; chemokine; cytotoxic; cytotoxicity; defined contribution; design; gene complementation; human disease; immunogenicity; lung injury; methicillin resistant Staphylococcus aureus; mortality; mutant; neutrophil; novel therapeutic intervention; pandemic disease; prevent; public health relevance; research study; synergism; treatment strategy

DESCRIPTION (provided by applicant): Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), especially the pandemic USA300 clone, is associated with severe infections and high mortality rates, particularly in patients with pneumonia. USA300 produces Panton-Valentine leukocidin (PVL), a potent exotoxin that lyses polymorphonuclear leukocytes (PMNs). It has been generally assumed that PVL accounts for hypervirulence of USA300 and has a key role in pathogenesis of necrotizing pneumonia, but data from rodent infection models are conflicting. Rodent PMNs are less susceptible than human PMNs to PVL cytotoxicity, which may account for the inconclusive results. Rabbit and human PMNs are similar in their susceptibility to PVL. Postulating that PMNs play a role in the tissue destructive process (and therefore susceptibility of this target cell to PVL effects matters), we developed a rabbit model of pneumonia. In this model, an isogenic PVL-negative USA300 mutant was attenuated in its capacity to cause lethal pneumonia compared to the PVL-positive parent; virulence was fully restored in the PVL-complemented mutant. Infection with the PVL-positive strain was remarkably similar to the human disease. Airspace instillation of purified PVL alone induced rapid onset of acute lung injury and lung inflammation. The overall objective of this project is to determine the mechanisms of PVL-induced acute lung injury, lung inflammation and lethal necrotizing pneumonia. Four specific aims are proposed. Aim 1. To determine the role of host inflammatory response in PVL-induced necrotizing pneumonia. We hypothesize that PVL-induced acute lung injury is mediated by PMNs. To test this hypothesis, we will determine whether blocking interleukin 8, the principal chemokine that recruits PMNs into the lung, attenuates PVL-induced acute lung injury and lung inflammation. Aim 2. To determine whether PVL and related bicomponent toxins, leukocidin (LukED) and -haemolysin (HlgABC), individually or synergistically induce acute lung injury and lung inflammation. We will investigate whether deletion of the lukED and hlgABC genes attenuates virulence; whether gene complementation restores virulence; and determine the levels of LukED and HlgABC expression during infection. Potential synergism among PVL, LukED and HlgABC in inducing acute lung injury and lung inflammation also will be investigated as this information has important implications for designing therapeutic interventions. Aim 3. To determine the relative effects of PVL, -hemolysin (HLA), and -type phenol-soluble modulins (PSM-) on acute lung injury and necrotizing pneumonia in the rabbit model. These experiments will determine whether other exotoxins similar in their activities to PVL contribute to virulence in the pneumonia model. Aim 4. To determine whether passive and active immunization protects against PVL-induced lung injury and death in the rabbit pneumonia model. Our proposed experiments will increase knowledge of the role of PVL and related toxins in pathogenesis of lung injury and establish a basis for the development of new therapeutic approaches. PUBLIC HEALTH RELEVANCE: Because of the high mortality rate associated with necrotizing hemorrhagic pneumonia caused by Panton Valentine leukocidin (PVL)-producing Staphylococcus aureus, there is an urgent need to understand better the mechanisms of this toxin-mediated disease and develop new therapeutic approaches. We propose to use a rabbit model to investigate the mechanisms of PVL and related toxins in causing acute lung injury and lung inflammation. Specific treatment strategies to block the toxigenic effects of PVL will be evaluated in the rabbit model.

描述（由申请人提供）：与社区相关的甲氧西林金黄色葡萄球菌（CA-MRSA），尤其是大流行的USA300克隆，与严重的感染和高死亡率有关，尤其是在肺炎患者中。 USA300产生Panton-Valentine Liukocidin（PVL），这是一种有效的外毒素，可溶解多形核白细胞（PMNS）。通常假定PVL解释了USA300的过度投资性，并且在坏死性肺炎的发病机理中具有关键作用，但是来自啮齿动物感染模型的数据是相互矛盾的。啮齿动物PMN比人类PMN对PVL细胞毒性不太敏感，这可能解释了不确定的结果。兔子和人类PMN的敏感性相似。假设PMN在组织破坏性过程中起作用（因此该目标细胞对PVL效应很重要），我们开发了肺炎的兔模型。在此模型中，与PVL阳性父母相比，将同源性PVL阴性的USA300突变体衰减，以引起致命性肺炎。毒力在PVL补充的突变体中完全恢复。 PVL阳性菌株的感染与人类疾病非常相似。空域对单独纯化的PVL滴注会引起急性肺损伤和肺部炎症的快速发作。该项目的总体目的是确定PVL诱导的急性肺损伤，肺部炎症和致命坏死性肺炎的机制。提出了四个具体目标。目的1。确定宿主炎症反应在PVL诱导的坏死性肺炎中的作用。我们假设PVL诱导的急性肺损伤是由PMN介导的。为了检验这一假设，我们将确定阻断白介素8（主要趋势PMN中的主要趋化因子）是否会减弱PVL诱导的急性肺损伤和肺部炎症。目的2。确定PVL和相关的双成分毒素，白细胞素（LUKED）和-Haemolysin（HLGABC）是单独或协同诱导急性肺损伤和肺部炎症。我们将研究LUKED和HLGABC基因的缺失是否会减轻毒力。基因互补是否恢复毒力；并确定感染过程中LUKED和HLGABC表达的水平。 PVL，LUKED和HLGABC在诱发急性肺损伤和肺部炎症中的潜在协同作用也将被研究，因为此信息对设计治疗干预措施具有重要意义。目的3。确定PVL，-Hemolysin（HLA）和-Type苯酚可溶性模量（PSM-）对兔模型中急性肺损伤和坏死性肺炎的相对影响。这些实验将确定其他外毒素在活性中与PVL相似，在肺炎模型中有助于毒力。目标4。确定被动和主动免疫是否可以防止兔肺炎模型中PVL诱导的肺损伤和死亡。我们提出的实验将增加对PVL和相关毒素在肺损伤发病机理中的作用的了解，并为开发新的治疗方法的发展提供基础。 公共卫生相关性：由于由Panton Valentine Liukocidin（PVL）产生的金黄色葡萄球菌引起的死亡率高死亡率与坏死性肺炎相关，因此迫切需要更好地了解这种毒素介导的疾病的机制，并开发出新的治疗方法。我们建议使用兔模型研究PVL和相关毒素在引起急性肺损伤和肺部炎症中的机制。将在兔模型中评估阻止PVL毒素作用的特定治疗策略。