The role of the Rab32/BLOC3 host defence pathway in controlling Staphylococcus aureus infections

S.金黄色葡萄球菌是畜牧业和兽医学中的一个新问题，我们最近的研究表明牲畜如何成为致病性金黄色葡萄球菌的来源。我们最近发现了一种抗微生物运输途径，该途径可以阻止伤寒沙门氏菌（伤寒的病原体）在小鼠巨噬细胞中的存活。该途径的核心成分是小的GTdR ab 32及其鸟嘌呤核苷酸交换因子BLOC 3（2，3）。金黄色葡萄球菌的毒力和宿主特异性可能与其基因型有关。金黄色葡萄球菌S.金黄色葡萄球菌可能已经进化出了中和这一途径的策略，从而获得在特定宿主免疫细胞内生存的能力，从而增加其致病潜力。人和动物来源的金黄色葡萄球菌菌株对RAB 32/BLOC-3途径的敏感性。具体而言，我们将回答以下问题：1）毒力与RAB 32/BLOC-3通路敏感性之间是否存在相关性？2)有没有什么分子证据可以解释易感性的差异？2)研究了S.金黄色葡萄球菌与来自不同物种的巨噬细胞。具体来说，我们将回答以下问题：1）细菌是否主动侵入巨噬细胞？2)它们是如何在巨噬细胞内存活的？3)是否存在宿主限制/特异性？如果是，限制/特异性是否取决于宿主或细菌因素？Baldassarre博士在粘附受体和肌动蛋白细胞骨架等领域拥有广泛的分子生物学专业知识。这些细胞系统对巨噬细胞吞噬作用和微生物杀伤至关重要。它们也是S.金黄色葡萄球菌感染菲茨杰拉德教授是S.金黄色葡萄球菌的致病性，并使用一系列的分子和基因组工具，以了解起源和进化的S。金黄色葡萄球菌感染的人类和牲畜。两名主管的存在与重叠和互补的专业知识将确保学生将在整个项目中得到全面的指导。它还将保证在一系列技术方面的一流培训，例如：-微生物技术，包括分子生物学，细菌生理学，无菌技术，微生物的生长和培养;-分子技术，如PCR，克隆，基因敲除的创建（包括CRISPR/Cas9）;哺乳动物细胞培养和S. - 显微镜技术，包括荧光宽视野和共聚焦显微镜，实时成像和3D重建。

S. aureus is an emerging problem in animal agriculture and veterinary medicine and our recent studies have shown how livestock could represent a source of pathogenic S. aureus (1) with the potential to spread in human populations.We have recently discovered an antimicrobial traffic pathway that prevents the survival of Salmonella Typhi, the agent of typhoid fever, in mouse macrophages. Central components of this pathway are the small GTPase Rab32 and its guanine nucleotide exchange factor BLOC3 (2,3).Our hypothesis is that this pathway is also critical for the killing of S. aureus and it may be responsible for the virulence and host-specificity of different S. aureus strains. S. aureus may have evolved strategies to neutralise this pathway gaining the ability to survive inside specific host immune cells and therefore increasing their pathogenic potential.In this project we will test the above hypothesis pursuing the following aims.We will: 1) Test a range of S. aureus strains, of both human and animal origin, for their sensitivity to the RAB32/BLOC-3 pathway. Specifically, we will answer the following questions: 1) Is there any correlation between virulence and the RAB32/BLOC-3 pathway sensitivity? 2) Is there any molecular evidence that can explain any difference in susceptibility?2) Study the interaction of S. aureus with macrophages from different species. Specifically, we will answer the following questions: 1) Do the bacteria actively invade the macrophages? 2) How they survive inside the macrophages? 3) Is there any host restriction/specificity? If so, is the restriction/specificity depending on host or bacterial factors?Dr Baldassarre has an extensive molecular biology expertise in fields such as adhesion receptors and actin cytoskeleton. Those are cellular systems crucial for macrophage phagocytosis and microbial killing. They are also systems hijacked during S. aureus infection. Prof Fitzgerald is an expert in S. aureus pathogenicity and uses a range of molecular and genomic tools to understand the origin and evolution of S. aureus infection in human and livestock.The presence of two supervisors with both overlapping and complementary expertise will ensure that the student will receive a full guidance throughout the project. It will also guarantee a first-class training in a range of techniques such as:- microbial techniques including molecular biology, bacterial physiology, sterile technique, growth and culture of microorganisms;- molecular techniques such as PCR, cloning, creation of gene knockouts (including CRISPR/Cas9); mammalian cell cultures and S. aureus infection;- microscopy techniques including fluorescent wide field and confocal microscopy, live imaging and 3D reconstruction.