Mucosal colonization and dissemination of P. aeruginosa

描述（由申请人提供）：本项目的中心目标是更好地了解免疫功能低下患者中由LPS-smooth菌株P. aeruginosa菌株引起的感染的发病机制和免疫。基于发起人实验室和合作者先前的研究，我们建立了中性粒细胞减少期间铜绿假单胞菌胃肠道定植和全身传播的可重复小鼠模型。使用该模型的初步研究已经确定了胃肠道定植和传播所必需的几个因素。值得注意的是，不需要在定植过程中发挥重要作用的毒力因子，即丸和鞭毛，而需要lps -外核多糖和o侧链。中性粒细胞减少的持续时间和强度与环磷酰胺剂量有关，对于确定传播所需的毒力因素很重要。这些初步实验得出以下可验证的假设：P. aeruginosa在胃肠道粘膜定殖、易位和引起菌血症所需的表面因子尚不完全清楚。这些因素的鉴定可以在小鼠模型中完成，该模型将定义病原体毒力因素（定植和易位因素）和宿主免疫反应（细胞和体液免疫效应物）。这些发现可能会导致有效破坏粘膜定植和传播的方法，并减少铜绿假单胞菌感染对免疫功能低下宿主的影响。在Aim 1中，P. aeruginosa建立胃肠道定植、易位和传播所需的毒力因子将使用微阵列和TraSH（转座子位点杂交）技术进行鉴定，并将创建突变体用于定植/传播模型中进行测试。在Aim 2中，宿主免疫效应物（细胞和体液先天免疫）的作用是防止铜绿假单胞菌定植和传播所必需的，将进一步描述。候选人寻求一个密集的，正式的，有指导的培训，以提供必要的智力和技术工具，以实现独立作为一个科学家。作为儿科血液学/肿瘤学和传染病的专家，他的长期目标是制定预防或改善铜绿假单胞菌感染后果的策略和潜在治疗方法。

DESCRIPTION (provided by applicant): The central goal of this project is to gain a better understanding of the pathogenesis of and immunity to infections caused by LPS-smooth strains P. aeruginosa strains in immunocompromised patients. Based on previous studies by the sponsor's laboratory and collaborators, we have established a reproducible mouse model of P. aeruginosa gastrointestinal-colonization and systemic spread during neutropenia. Preliminary studies using this model have identified several factors that are necessary for gastrointestinal colonization and dissemination. Of note, virulence factors expected to play an important role in colonization, namely pill and flagella, were not needed whereas LPS-outer core polysaccharide and O-side chains were. The duration and intensity of neutropenia, related to cyclophosphamide dose, was important in identifying virulence factors needed for dissemination. These preliminary experiments have led to the following testable hypothesis: Surface factors of P. aeruginosa needed to colonize the gastrointestinal mucosa and to translocate and cause bacteremia are not fully known. Identification of such factors can be accomplished in a murine model that will define both pathogen virulence factors (colonization and translocation factors) and host immune responses (cellular and humoral immune effectors). The findings could lead to means to effectively disrupt mucosal colonization and dissemination and diminish the impact of P. aeruginosa infection in immunocompromised hosts. In Aim 1, virulence factors needed by P. aeruginosa to establish gastrointestinal colonization, translocation, and dissemination will be identified by use of microarray and TraSH (transposon site hybridization) technology, and mutants will be created for testing in the colonization/dissemination model. In Aim 2, the role of host immune effectors (cellular and humoral innate immunity) that are necessary for preventing P. aeruginosa colonization and dissemination will be further delineated. The candidate seeks an intensive, formal, and mentored training to provide the necessary intellectual and technical tools to achieve independence as a scientist. As a specialist in pediatric hematology/oncology and infectious diseases, his long-term goal is to develop strategies and potential therapies to prevent or ameliorate the consequences of P. aeruginosa infections.