Defining the molecular steps in the interaction of pathogenic bacteria with alveolar macrophages a key step in pathogenesis and disease

我们最近证明，据报道，细菌是唯一的细胞外病原体，在侵袭性感染之前，在巨噬细胞的特定亚群中经历了细胞内复制的阶段。这种相互作用由巨噬细胞受体CD169 （siglec1）介导。与CD169的相互作用和CD169+巨噬细胞的摄取已被报道用于一系列唾液化病原体。其他具有唾液化表面碳水化合物或蛋白质的细菌极有可能具有相同或相似的cd169结合相关表型。虽然CD169+细胞的摄取已经被描述，但CD169+细胞中细菌细胞内复制的发生，导致这种细胞内复制的具体步骤以及这些事件在感染发病机制中的作用，最近才被我们的团队发现肺炎链球菌。该项目的基础假设是细菌和CD169+细胞之间相互作用中的特定分子事件可以指导感染预防策略的优化。为了验证这一假设，该项目将解决以下两个目标：-表征CD169+巨噬细胞中不同病原体细胞内命运的步骤-表征参与这种相互作用的微生物因素。为了设计一种强大的方法，该项目将从两个模型病原体开始解决这些相互作用。上面列出的其他物种可在实验室中获得，并记录在HBA表格上，并将在项目的后期阶段使用，以测试结果的更广泛有效性。猪肺泡和滤泡周围脾巨噬细胞是CD169+细胞的主要来源。该学生所在的实验室最近建立了原代猪脾和肺泡巨噬细胞培养模型。这些模型将用于研究细菌与CD169+细胞相互作用的具体步骤，包括吞噬、液泡成熟和细胞死亡机制。这些工具将包括共聚焦显微镜、细胞荧光法、细胞因子分析、基因表达谱和细菌突变体检测。为了测试对感染结果的影响，将在小鼠模型中进行一系列有限的实验性感染。培训范围包括共聚焦显微镜、细胞荧光学、细胞和器官培养、细菌学、下一代序列分析和动物处理。CASE项目的总体目标是在紧密的学术与工业互动中，为学生提供一个关于前沿科学主题的多学科培训计划。

We have recently demonstrated that bacteria, reported to be exclusive extracellular pathogens, undergo a phase of intracellular replication in a specific subset of macrophages prior to invasive infection. This interaction is mediated by the macrophage receptor CD169 (siglec1). Interaction with CD169 and uptake by CD169+ macrophages has been reported for a series of sialylated pathogens. Other bacteria with sialylated surface carbohydrates or proteins highly likely to share the same or similar CD169-binding associated phenotypes. While uptake by CD169+ cells has been described, the occurrence of bacterial intracellular replication in CD169+ cells, the specific steps leading to this intracellular replication and the role of these events in the pathogenesis of infection, have only been discovered most recently by our group for Streptococcus pneumoniae. The hypothesis at the basis of this project is that specific molecular events in the interaction between bacteria and CD169+ cells can guide optimisation of strategies for infection prevention. To test this hypothesis the project will address the following two objectives:- Characterisation of the steps in the intracellular fate of different pathogens, in CD169+ macrophages- Characterisation of the microbial factors involved in this interaction In order to design a robust approach, the project will address these interactions starting with two model pathogens. The other species listed above are available in the lab and recorded on the HBA forms and will be utilised in the later phases of the project to test the broader validity of the findings. As main source of CD169+ cells, porcine alveolar and peri-follicular splenic macrophages will be used. The laboratory hosting the student has recently set up models for primary porcine splenic and alveolar macrophage cultures. These models will be exploited to investigate the specific steps in the interaction of the bacteria with CD169+ cells including phagocytosis, vacuole maturation and mechanism of cell death. The tools will include confocal microscopy, cytofluorimetry, cytokine assays, gene expression profiling and the testing of panels of bacterial mutants. To test the impact on the outcome of infection a limited series of experimental infection in murine models will be performed.The training will range from confocal microscopy, cytofluorimetry, cell and organ culture, bacteriology, next generation sequence analysis, to animal handling. The overall aim of the CASE project is to provide the student with a multidisciplinary training program on a cutting edge scientific topic within a tight academic-industrial interaction.