Polymicrobial interactions in the lung.

描述(申请人提供)：铜绿假单胞菌是一种机会致病菌，也是慢性阻塞性肺疾病(COPD)、社区获得性肺炎(CAP)、呼吸机相关肺炎(VAP)、非CF型支气管扩张和囊性纤维化(CF)患者的重要病原体。最近的研究表明，肺部的病毒感染和铜绿假单胞菌感染是协同作用的，并极大地促进了与COPD、CF、CAP、VAP和非CF支气管扩张相关的发病率和死亡率。我研究的长期目标是阐明铜绿假单胞菌和呼吸道病毒协同作用导致肺部疾病的细胞和分子机制。我的短期研究目标是阐明铜绿假单胞菌感染干扰宿主清除呼吸道病毒的机制。铜绿假单胞菌分泌一种名为Cif(CFTR抑制因子)的蛋白质，最初命名为Cif，是因为它能够抑制CFTR介导的呼吸道细胞分泌氯的能力，该蛋白质由PA2934(或cif)基因编码。CIF是由实验室和临床分离的铜绿假单胞菌分泌的，通过下调CFTRCl的分泌和粘液纤毛的清除来抑制宿主的免疫反应。此外，Cif减少了TAP1(与抗原处理相关的转运蛋白)的丰度，我最近的初步研究发现，TAP1抑制了I类MHC分子对甲型流感病毒抗原的呈递，并抑制了细胞毒性T淋巴细胞(CTL)清除病毒感染的能力。我的初步数据还表明，宿主在应对病毒病原体时释放的细胞因子，即干扰素-3，增加了铜绿假单胞菌Cif的分泌。目前对分泌的细菌蛋白如何抑制宿主对病毒病原体的免疫反应知之甚少，也没有多少数据阐明宿主免疫反应如何改变微生物病原体释放细菌毒素的方式。因此，我将使用体外生化、高分辨率成像和体内免疫学技术来测试这一建议中的下列四个特定目标：(1)测试Cif减少抗原提呈和CTL介导的清除的假设；(2)测试Cif减少流感病毒抗原提呈和CTL介导的清除的假设；(3)测试铜绿假单胞菌和RSV混合感染通过减少RSV的病毒抗原提呈和CTL清除并促进铜绿假单胞菌定植而使每个病原体受益的假设；以及(4)测试宿主免疫反应增加铜绿假单胞菌毒力因子分泌的假设。我预计这些研究将阐明铜绿假单胞菌如何降低肺部清除病毒感染的能力，并最终确定新的治疗方法来控制铜绿假单胞菌和呼吸道病毒的联合感染。 公共卫生相关性：铜绿假单胞菌是一种机会致病菌，也是慢性阻塞性肺疾病(COPD)、社区获得性肺炎(CAP)、呼吸机相关肺炎(VAP)、非纤维性支气管扩张症和囊性纤维化(CF)患者的重要病原体。最近的研究表明，肺部的病毒感染和铜绿假单胞菌感染是协同作用的，并极大地促进了与COPD、CF、CAP、VAP和非CF支气管扩张相关的发病率和死亡率。我研究的长期目标是阐明铜绿假单胞菌和呼吸道病毒协同作用导致肺部疾病的细胞和分子机制，并最终确定控制铜绿假单胞菌和呼吸道病毒联合感染的新的治疗方法。

DESCRIPTION (provided by applicant): Pseudomonas aeruginosa is an opportunistic pathogen and an important pathogen in patients with chronic obstructive pulmonary disorder (COPD), community acquired pneumonia (CAP), ventilator-associated pneumonia (VAP), non-CF bronchiectasis and cystic fibrosis (CF). Recent studies suggest that viral and P. aeruginosa infections of the lung are synergistic and dramatically contribute to the morbidity and mortality associated with COPD, CF, CAP, VAP, and non-CF bronchiectasis. The long-term goal of my research is to elucidate the cellular and molecular mechanisms whereby P. aeruginosa and respiratory viruses synergize to cause lung disease. My short-term research goal is to elucidate the mechanism whereby P. aeruginosa infection interferes with host clearance of respiratory virus. P. aeruginosa secretes a protein called Cif (CFTR Inhibitory Factor, originally named because of its ability to inhibit CFTR-mediated Cl secretion by airway cells), which is coded by the PA2934 (or cif) gene. Cif, which is secreted by laboratory and clinical isolates of P. aeruginosa, inhibits the host immune response by down-regulating CFTR Cl secretion and mucociliary clearance. In addition, Cif reduces the abundance of TAP1 (Transporter Associated with Antigen Processing), which my recent preliminary studies reveal, suppresses influenza A virus antigen presentation by class I MHC molecules and the ability of cytotoxic T lymphocytes (CTL) to clear viral infections. My preliminary data also demonstrate that cytokines, namely interferon-3, released by the host in response to viral pathogens, increase the secretion of Cif from P. aeruginosa. Very little is known about how secreted bacterial proteins suppress the host immune response to viral pathogens, and there is minimal data elucidating how the host immune response alters the release of bacterial toxins from microbial pathogens. Accordingly, I will use in vitro biochemical, high resolution imaging, and in vivo immunological techniques to test the following four specific aims in this proposal: (1) Test the hypothesis that Cif reduces antigen presentation and CTL-mediated clearance; (2) Test the hypothesis that Cif reduces influenza virus antigen presentation and CTL-mediated clearance; (3) Test the hypothesis that P. aeruginosa and RSV co-infection benefits each pathogen by reducing viral antigen presentation and CTL-clearance of RSV and promoting P. aeruginosa colonization; and (4) Test the hypothesis that the host immune response increases virulence factor secretion by P. aeruginosa. I anticipate that these studies will elucidate how P. aeruginosa reduces the ability of the lung to clear viral infections and, ultimately, identify new therapeutic approaches to control combined P. aeruginosa and respiratory virus infections. PUBLIC HEALTH RELEVANCE: Pseudomonas aeruginosa is an opportunistic pathogen and an important pathogen in patients with chronic obstructive pulmonary disorder (COPD), community acquired pneumonia (CAP), ventilator-associated pneumonia (VAP), non-CF bronchiectasis and cystic fibrosis (CF). Recent studies suggest that viral and P. aeruginosa infections of the lung are synergistic and dramatically contribute to the morbidity and mortality associated with COPD, CF, CAP, VAP, and non-CF bronchiectasis. The long-term goal of my research is to elucidate the cellular and molecular mechanisms whereby P. aeruginosa and respiratory viruses synergize to cause lung disease and, ultimately, identify new therapeutic approaches to control combined P. aeruginosa and respiratory virus infections.