The reverse transmigration of Salmonella-infected cells into the bloodstream

沙门氏菌感染细胞逆向迁移进入血流

• 批准号: 8957744
• 负责人: MICAH WORLEY
• 金额: $ 45万
• 依托单位: UNIVERSITY OF LOUISVILLE
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-20 至 2019-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8957744
• 关键词: Animal Model; Apical; Bacteria; Binding; Biochemical Genetics; Biological Assay; Blood Circulation; Cell membrane; Cell surface; Cells; Cessation of life; Communicable Diseases; Coupling; Data; Defect; Dendritic Cells; Endothelium; Equilibrium; Equus caballus; Gastrointestinal tract structure; Genetic; Human; Immune response; In Vitro; Infection; Inflammation; Integration Host Factors; Investigation; Knowledge; Lead; Lymphatic System; Mediating; Microbe; Modeling; Molecular; Multi-Drug Resistance; Mus; Oral mucous membrane structure; Organ; Pathogenesis; Pathway interactions; Process; Property; Proteins; Public Health; Regulation; Route; Salmonella; Salmonella infections; Salmonella typhimurium; Sepsis; Site; Spleen; Structure of parenchyma of lung; Testing; Tissues; Travel; Virulence Factors; Work; cancer type; cell motility; cell type; combat; human BCAR1 protein; in vitro Assay; in vivo; innovation; insight; microbial; microbial host; migration; monolayer; mutant; novel; palmitoylation; pathogen; public health relevance; research study; resistant strain; tool

 DESCRIPTION (provided by applicant): Salmonella is a major public health problem. There are more than one billion new Salmonella infections of humans each year that lead to more than three million deaths. The problem is greatly exacerbated by the emergence of multi-drug resistant strains. In addition to public health concerns, S. Typhimurium is also studied because it is a model pathogen without parallel for dissecting basic pathogenic processes as it combines the advantages of excellent genetics with tractable animal models of infection. Salmonella is believed to exploit migratory host cells as Trojan horses to spread from the gastrointestinal (GI) tract to internal organs. Dendritic cells are one such cell type, which can reenter the bloodstream by traversing endothelium in the basal to apical direction in a normal host process referred to as reverse transmigration. Reverse transmigration is likely relevant to numerous infectious processes including the spread of pathogenic microbes from the GI tract, lung tissue and the oral mucosa to the systemic circulation. Not surprisingly, infected cells do not normally reverse transmigrate, presumably because this could create a serious bloodstream infection. The host likely has mechanisms to detect conserved microbial components and balances the need to resolve inflammation with inhibiting the spread of microbes appropriately. Salmonella Typhimurium exploits the reverse transmigration pathway to deeper tissue, manipulating the migratory properties of infected cells to enter the bloodstream within them directly from the GI tract as an unappreciated component of its pathogenesis. Salmonella achieves this in part by secreting the type III effector SrfH into infected cells to subvert the host protein TRIP6 to stimulate reverse transmigration. In Aim 1, we will employ a variety of biochemical and genetic tools to delineate mechanistically exactly how the SrfH/TRIP6 interaction promotes travel through the reverse transmigration pathway. As a mutant deficient in type III secretion generally has a larger defect in triggering the reverse transmigration of infected cells than a srfH mutant, additional microbial and host factors must be involved. In Aim 2, we will utilize an in vitro revere transmigration assay along with murine intra-host dissemination experiments to determine the impact of the 9 host factors that are known to regulate the reverse transmigration of uninfected cells on the reverse transmigration of ones infected with Salmonella. Also, we will determine if these molecules are perturbed during infections. Finally, we will utilize the in vitro assay to identify the additional type III effector(s) involved in exploiting the reverse transmigration pathway to the bloodstream.

 描述（由申请人提供）：沙门氏菌是一个主要的公共卫生问题。每年有超过10亿人新感染沙门氏菌，导致300多万人死亡。多药耐药菌株的出现大大加剧了这一问题。除了公共卫生问题，S。鼠伤寒也被研究，因为它 是解剖基本致病过程的一种无与伦比的模式病原体，因为它结合了优良的遗传学优势和易于处理的感染动物模型。沙门氏菌被认为利用迁移宿主细胞作为特洛伊木马从胃肠道（GI）传播到内脏。树突状细胞是这样一种细胞类型，其可以通过在称为逆迁移的正常宿主过程中以基底至顶端方向穿过内皮而重新进入血流。逆轮回可能与许多感染过程有关，包括病原微生物从胃肠道、肺组织和口腔粘膜传播到体循环。毫不奇怪，受感染的细胞通常不会逆转移，大概是因为这可能会造成严重的血液感染。宿主可能具有检测保守的微生物成分的机制，并在解决炎症的需要与适当抑制微生物传播之间取得平衡。鼠伤寒沙门氏菌利用反向迁移途径进入更深的组织，操纵受感染细胞的迁移特性，直接从胃肠道进入它们体内的血流，作为其发病机制的一个不受重视的组成部分。沙门氏菌通过分泌III型效应物SrfH进入受感染的细胞来破坏宿主蛋白TRIP 6以刺激逆迁移来实现这一点。在目标1中，我们将采用各种生物化学和遗传学工具来精确地描述SrfH/TRIP 6相互作用如何通过逆轮回途径促进旅行。由于III型分泌缺陷的突变体通常在触发感染细胞的反向迁移方面比srfH突变体具有更大的缺陷，因此必须涉及额外的微生物和宿主因素。在目标2中，我们将利用体外逆转移行试验沿着小鼠宿主内播散实验，以确定已知调节未感染细胞逆转移行的9种宿主因子对沙门氏菌感染细胞逆转移行的影响。此外，我们将确定这些分子在感染过程中是否受到干扰。最后，我们将利用体外试验来鉴定参与利用血液逆迁移途径的其他III型效应物。