Defining the Role of the Plasminogen Activator Protease in the Early Events that Establish Primary Pneumonic Plague

项目摘要 肺鼠疫是由鼠疫耶尔森氏菌引起的最致命的疾病形式。感染后早期，鼠疫耶尔森氏菌 在肺部颠覆宿主的先天免疫机制，并在致死前大量复制 宿主炎症反应。因此，一旦识别出症状，肺鼠疫就很难治疗。 本方案引入耶尔森氏菌纤溶酶原激活物蛋白水解酶(Pla)作为早期 肺内宿主/病原体的相互作用。解放军是公认的毒力因素，已知是必不可少的 肺鼠疫的发病机制不明。这里提出的工作考察了 在肺部感染过程中，聚乳酸既是粘附素又是一种蛋白酶。这项工作的目标是定义 关键耶尔森氏菌毒力因子Pla在肺鼠疫早期事件中的作用 鼠疫杆菌抵抗宿主炎症反应的清除，以建立肺部的初始复制阶段。 这项提议的战略概述如下： 明确目标1.明确Pla介导的T3s在肺鼠疫中的作用。血小板的粘附素功能 在肺鼠疫早期，促进肺泡巨噬细胞靶向3型分泌物(T3s)。目标1 将产生并测试Pla的突变体，以了解Pla如何调节黏附，并表征 Pla介导的黏附和体内T3s的重要性。此外，PlA介导的T3s对宿主细胞的影响 将在感染期间评估对T3s的先天免疫反应，以了解鼠疫杆菌如何限制宿主 感染早期的反应性。 特定目的2.鉴定肺鼠疫期间Pla的新的蛋白降解功能。初步数据 已发现Pla的两个新功能可能与发病机制有关。蛋白质组学的方法将是 用于在原发肺炎鼠疫期间早期鉴定和表征Pla蛋白分解活性。 具体目标3.确定关键宿主细胞类型和动态，负责建立早期Pre-Pre 肺炎鼠疫期间的炎症期。初步数据显示，Pla的删除 破坏鼠疫杆菌限制肺部早期先天免疫反应的能力。在目标3中，我们将评估主机 PLA存在和不存在时肺内细胞动力学和先天免疫反应的研究 鼠疫杆菌能够颠覆最初的炎症反应，并在肺部建立感染。

Project Summary Pneumonic plague is the deadliest form of disease caused by Yersinia pestis. Early after infection, Y. pestis subverts host innate immune mechanisms in the lung and replicates to high numbers before the onset of lethal host inflammatory responses. As a result, pneumonic plague is difficult to treat once symptoms are recognized. This proposal introduces the Yersinia Plasminogen activator protease (Pla) as an important mediator of early host/pathogen interactions in the lung. Pla is well-established virulence factor known to be essential to the pathogenesis of pneumonic plague via an unknown function. The work proposed here examines the dual role of Pla, as both an adhesin and a protease, during pulmonary infection. The objective of this work is to define the function of the critical Yersinia virulence factor Pla in the early events of pneumonic plague to understand how Y. pestis resists clearance by host inflammatory responses to establish an initial replicative phase in the lungs. The strategy for this proposal is outlined below: Specific Aim 1. Define the role of Pla-mediated T3S during pneumonic plague. The adhesin function of Pla facilitates targeting of alveolar macrophages for type 3 secretion (T3S) early during pneumonic plague. Aim 1 will generate and test mutants of Pla to understand how Pla mediates adherence, and characterize the importance of Pla-mediated adherence and T3S in vivo. Further, the impact of Pla-mediated T3S on host cell innate immune responses to T3S will be evaluated during infection to understand how Y. pestis limits host responsiveness early during infection. Specific Aim 2. Characterize novel proteolytic functions of Pla during pneumonic plague. Preliminary data has identified two novel functions of Pla that may contribute to pathogenesis. A proteomics approach will be used to identify and characterize Pla proteolytic activity early during primary pneumonic plague. Specific Aim 3. Identify key host cell types and dynamics responsible for establishing an early pre- inflammatory disease phase during pneumonic plague. Preliminary data indicates that deletion of Pla disrupts the ability of Y. pestis to limit early innate immune responses in the lung. In Aim 3 we will evaluate host cell dynamics and innate immune responses in the lung in the presence and absence of Pla to understand how Y. pestis is able to subvert initial inflammatory responses and establish infection in the lung.