Wang Ziyan, Zhu Fei
College of Animal Science and Technology, Zhejiang Agriculture and Forestry University, Hangzhou, China.
PLoS One. 2018 Jan 5;13(1):e0190490. doi: 10.1371/journal.pone.0190490. eCollection 2018.
Staphylococcus aureus is an important pathogen which is often the cause of major morbidity and mortality in both hospital and community settings. For this reason, we investigated the host cell early immune resoponse to S. aureus infection using genome-wide analysis. To do this, we infected Mus musculus RAW264.7 cells with S. aureus alone or in the presence of free peptidoglycan (PG), which appears in the S. aureus cell wall. Post infection, we performed a genome-wide analysis of RAW246.7 cells to identify significant changes in the gene expression profile. Further, we analyzed the infected RAW246.7 cells with transmission electron microscopy looking for the presence of bacterial cells inside the host cell. We also used flow cytometry to determine whether cells had induced apoptosis. The results showed that S. aureus induced apoptosis in the RAW246.7 cells but did not effectively clear away intracellular bacteria cells. However, S. aureus + PG treatment inhibited the apoptosis and activated the host cell inflammation response, possibly involving NF-κB and JAK-STAT pathways, as identified by genome-wide analysis, in RAW246.7 cells. Our study demonstrated for the first time that an independent application of free PG was capable of activating immune responses the host cells.
金黄色葡萄球菌是一种重要的病原体，在医院和社区环境中常常导致严重的发病和死亡。因此，我们使用全基因组分析研究了宿主细胞对金黄色葡萄球菌感染的早期免疫反应。为此，我们单独用金黄色葡萄球菌或在游离肽聚糖（PG）存在的情况下感染小家鼠RAW264.7细胞，游离肽聚糖存在于金黄色葡萄球菌细胞壁中。感染后，我们对RAW246.7细胞进行全基因组分析，以确定基因表达谱中的显著变化。此外，我们用透射电子显微镜分析感染的RAW246.7细胞，寻找宿主细胞内细菌细胞的存在。我们还使用流式细胞术来确定细胞是否诱导了凋亡。结果表明，金黄色葡萄球菌诱导RAW246.7细胞凋亡，但不能有效清除细胞内细菌细胞。然而，金黄色葡萄球菌+PG处理抑制了凋亡并激活了宿主细胞炎症反应，全基因组分析确定这可能涉及RAW246.7细胞中的NF-κB和JAK-STAT途径。我们的研究首次证明，游离PG的单独应用能够激活宿主细胞的免疫反应。
