Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
Department of Molecular Genetics and Microbiology, College of Medicine, Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA.
Infect Immun. 2018 Sep 21;86(10). doi: 10.1128/IAI.00360-18. Print 2018 Oct.
causes the severe disease melioidosis. The bacterium subverts the host immune system and replicates inside cells, and host mortality results primarily from sepsis-related complications. Lipopolysaccharide (LPS) is a major virulence factor and mediator of sepsis that many pathogens capable of intracellular growth modify to reduce their immunological "footprint." The binding strength of LPS for human LPS binding protein (hLBP) was measured using surface plasmon resonance. The structures of lipid A isolated from under different temperatures were analyzed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and the gene expression of two lipid A remodeling genes, and , was investigated. The LPS was characterized for its ability to trigger tumor necrosis factor alpha (TNF-α) release and to activate caspase-11-triggered pyroptosis by introduction of LPS into the cytosol. Lipid A from long-term chronic-infection isolates was isolated and characterized by MALDI-TOF MS and also by the ability to trigger caspase-11-mediated cell death. Lipid A from 1026b and mutants were characterized by positive- and negative-mode MALDI-TOF MS to ultimately identify their role in lipid A structural modifications. Replication of and mutants and their complements within macrophages showed that lipid A remodeling can effect growth in host cells and activation of caspase-11-mediated cytotoxicity.
导致严重疾病类鼻疽。该细菌颠覆了宿主的免疫系统，并在细胞内复制，而宿主的死亡率主要是由与败血症相关的并发症导致的。脂多糖（LPS）是一种主要的毒力因子和败血症的介质，许多能够在细胞内生长的病原体都会对其进行修饰，以减少其免疫“足迹”。使用表面等离子体共振测量了 LPS 与人 LPS 结合蛋白（hLBP）的结合强度。通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）分析了在不同温度下从 中分离出的脂质 A 的结构，并研究了两个脂质 A 重塑基因 和 的基因表达。通过将 LPS 引入细胞质，研究了 LPS 触发肿瘤坏死因子-α（TNF-α）释放和激活 caspase-11 触发细胞焦亡的能力。通过 MALDI-TOF MS 分离和表征了来自长期慢性感染分离株的脂质 A，并通过其触发 caspase-11 介导的细胞死亡的能力进行了表征。通过正模式和负模式 MALDI-TOF MS 对 1026b 和 突变体的脂质 A 进行了表征，最终确定了它们在脂质 A 结构修饰中的作用。在巨噬细胞内复制 和 突变体及其互补物表明，脂质 A 的重塑可以影响宿主细胞内的生长和 caspase-11 介导的细胞毒性的激活。
