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

项目摘要 鼠疫是由鼠疫耶尔森氏菌引起的最致命的一种疾病。感染后早期，Y.鼠疫 破坏宿主在肺中的先天免疫机制，并在致命性疾病发生前大量复制。 宿主炎症反应。因此，肺鼠疫一旦发现症状就很难治疗。 该建议引入耶尔森氏菌纤溶酶原激活物蛋白酶（Pla）作为早期纤溶酶原激活物的重要介体。 肺中的宿主/病原体相互作用。Pla是一种公认的毒力因子，已知其对 肺鼠疫的发病机制通过一个未知的功能。这里提出的工作审查的双重作用， 在肺部感染中作为粘附素和蛋白酶的Pla。这项工作的目标是确定 关键耶尔森氏菌毒力因子Pla在肺鼠疫早期事件中的作用，以了解其如何 Y.鼠疫抵抗宿主炎症反应的清除，以在肺中建立初始复制阶段。 这项建议的战略概述如下： 具体目标1。明确肺鼠疫中Pla介导的T3 S的作用。Pla的粘附功能 促进肺鼠疫早期肺泡巨噬细胞3型分泌（T3 S）的靶向。要求1 将产生和测试Pla的突变体，以了解Pla如何介导粘附，并表征 PLA介导的粘附和T3 S在体内的重要性。此外，Pla介导的T3 S对宿主细胞的影响也可能与其对细胞周期的影响有关。 将在感染期间评估对T3 S的先天免疫应答以了解Y.鼠疫限制宿主 在感染早期的反应。 具体目标2。肺鼠疫期间新的蛋白水解功能的特点。初步数据 已经确定了两个新的功能，可能有助于发病机制。蛋白质组学方法将 用于在原发性肺鼠疫早期鉴定和表征Pla蛋白水解活性。 具体目标3。确定负责建立早期预处理的关键宿主细胞类型和动态 肺鼠疫期间的炎性疾病阶段。初步数据表明，删除Pla 破坏了Y的能力。以限制肺部的早期先天免疫反应。在目标3中，我们将评估主机 细胞动力学和先天性免疫反应在肺的存在和不存在的Pla，以了解如何 Y.鼠疫能够破坏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.