CHARACTERIZATION OF PSEUDOMONAS PHOSPHOLIPASES INVOLVED IN VIRULENCE

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。所列机构为 中心，不一定是研究者的机构。 囊性纤维化（CF）患者发病和死亡的最常见原因是铜绿假单胞菌感染引起的肺系统衰竭。铜绿假单胞菌对肺损伤的一个潜在机制是肺表面活性物质的破坏。表面活性物质功能障碍可导致小气道闭合和肺功能严重下降。虽然CF肺中表面活性物质功能障碍的临床意义尚未完全了解，但表面活性物质功能障碍可能导致急性加重期间肺功能降低。我们认为铜绿假单胞菌分泌的几种毒力因子在感染过程中降解表面活性剂，导致肺功能下降。 来自小鼠肺部感染模型的初步证据显示，铜绿假单胞菌感染的小鼠显示广泛的气道闭合。这种封闭的一部分是由于分泌的溶血性磷脂酶C，PlcH，但在plcH缺失菌株中仍然存在显着的表面活性剂功能障碍。我们假设PA 4921编码的分泌脂肪酶是铜绿假单胞菌肺部感染过程中表面活性剂降解的额外介质之一。在这项研究中，我们将验证预测的酶活性的PA 4921，并确定其诱导肺表面活性物质的转录调控机制。初步表征后，我们将在野生型和囊性纤维化跨膜调节因子敲除（CFTR KO）小鼠中检查PA 4921在肺力学改变中的作用。将在铜绿假单胞菌感染期间测量肺力学、表面活性物质组成和表面活性物质功能。将检测肺滴注纯化PA 4921酶是否足以改变肺力学和催化表面活性剂降解。这些实验将使我们能够确定PA 4921是否是适用于CF加重的潜在治疗靶点

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The most common cause of morbidity and mortality in patients with Cystic Fibrosis (CF) is pulmonary system failure caused by Pseudomonas aeruginosa infection. One potential mechanism of P. aeruginosa damage to the lung is destruction of lung surfactant. Surfactant dysfunction can lead to small airway closure and severely decreased lung function. While the clinical significance of surfactant dysfunction in the CF lung is not fully understood, surfactant dysfunction may result in reduced lung function during exacerbations. We propose that several virulence factors secreted by P. aeruginosa function to degrade surfactant during infection resulting in decreased lung function. Preliminary evidence from a mouse lung infection model shows that P. aeruginosa infected mice show extensive airway closure. Some of this closure is due to the secreted hemolytic phospholipase C, PlcH, but in a plcH deletion strain there remains significant surfactant dysfunction. It is our hypothesis that the secreted lipase encoded by PA4921 is one of the additional mediators of surfactant degradation during P. aeruginosa lung infection. In this study we will verify the predicted enzymatic activity of PA4921 and determine the transcriptional regulatory mechanism governing its induction in pulmonary surfactant. Following the initial characterization, we will examine the role of PA4921 in alteration of lung mechanics in both wild type and Cystic Fibrosis Transmembrane Regulator knock-out (CFTR KO) mice. Lung mechanics, surfactant composition, and surfactant function will be measured during P. aeruginosa infection. Pulmonary instillation of purified PA4921 enzyme will be tested for sufficiency to alter lung mechanics and catalyze surfactant degradation. These experiments will allow us to determine if PA4921 is a potential therapeutic target applicable to CF exacerbations