Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland 21201, United States.
Department of Pharmaceutical Science, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201, United States.
J Proteome Res. 2020 Mar 6;19(3):1258-1266. doi: 10.1021/acs.jproteome.9b00765. Epub 2020 Feb 24.
Sepsis remains one of the most lethal and costly conditions treated in U.S. hospitals, with approximately 50% of cases caused by Gram-negative bacterial infections. Septic shock is induced when lipopolysaccharide (LPS), the main component of Gram-negative outer bacterial membrane, signals through the Toll-like receptor 4 (TLR4) complex. Lethal endotoxemia, a model for septic shock, was induced in WT C57BL6 and TLR4 mice by administration of LPS. WT LPS treated mice showed high morbidity, while PBS treated LPS and treated TLR4 mice did not. ANOVA analysis of label-free quantification of longitudinal serum proteome revealed 182 out of 324 proteins in LPS injected WT mice that were significantly changed across four time points (0, 6, 12, and 18 h). No significant changes were identified in the two control groups. From the 182 identified proteins, examples of known sepsis biomarkers were validated by ELISA, which showed similar trends as MS proteomics data. Longitudinal analysis within individual mice produced 3-fold more significantly changed proteins than pair-wise comparison. A subsequent global analysis of WT and TLR4 mice identified pathways activated independent of TLR4. These pathways represent possible compensatory mechanisms that allow for control of Gram-negative bacterial infection regardless of host immune status.
败血症仍然是美国医院治疗中最致命和最昂贵的病症之一，其中约 50%的病例由革兰氏阴性细菌感染引起。当革兰氏阴性细菌外膜的主要成分脂多糖 (LPS) 通过 Toll 样受体 4 (TLR4) 复合物发出信号时，就会引发败血症性休克。通过给予 LPS，在 WT C57BL6 和 TLR4 小鼠中诱导致死性内毒素血症，这是败血症性休克的模型。WT LPS 处理的小鼠表现出高发病率，而 PBS 处理的 LPS 和处理的 TLR4 小鼠则没有。对 LPS 注射的 WT 小鼠的纵向血清蛋白质组进行无标记定量的方差分析，在四个时间点（0、6、12 和 18 小时），发现了 324 种蛋白质中有 182 种发生了显著变化。在两个对照组中未发现显著变化。从鉴定出的 182 种蛋白质中，通过 ELISA 验证了一些已知的败血症生物标志物，结果与 MS 蛋白质组学数据相似。与两两比较相比，对单个小鼠进行的纵向分析产生了 3 倍以上的显著变化蛋白。随后对 WT 和 TLR4 小鼠进行的全球分析确定了独立于 TLR4 激活的途径。这些途径代表了可能的代偿机制，无论宿主免疫状态如何，都可以控制革兰氏阴性细菌感染。
