BACKGROUND:Staphylococcus aureus, a leading cause of chronic or acute infections, is traditionally considered an extracellular pathogen despite repeated reports of S. aureus internalization by a variety of non-myeloid cells in vitro. This property potentially contributes to bacterial persistence, protection from antibiotics and evasion of immune defenses. Mechanisms contributing to internalization have been partly elucidated, but bacterial processes triggered intracellularly are largely unknown. RESULTS:We have developed an in vitro model using human lung epithelial cells that shows intracellular bacterial persistence for up to 2 weeks. Using an original approach we successfully collected and amplified low amounts of bacterial RNA recovered from infected eukaryotic cells. Transcriptomic analysis using an oligoarray covering the whole S. aureus genome was performed at two post-internalization times and compared to gene expression of non-internalized bacteria. No signs of cellular death were observed after prolonged internalization of Staphylococcus aureus 6850 in epithelial cells. Following internalization, extensive alterations of bacterial gene expression were observed. Whereas major metabolic pathways including cell division, nutrient transport and regulatory processes were drastically down-regulated, numerous genes involved in iron scavenging and virulence were up-regulated. This initial adaptation was followed by a transcriptional increase in several metabolic functions. However, expression of several toxin genes known to affect host cell integrity appeared strictly limited. CONCLUSION:These molecular insights correlated with phenotypic observations and demonstrated that S. aureus modulates gene expression at early times post infection to promote survival. Staphylococcus aureus appears adapted to intracellular survival in non-phagocytic cells.

译文

背景:尽管反复报道金黄色葡萄球菌在体外被多种非髓样细胞内在化,但金黄色葡萄球菌是慢性或急性感染的主要原因,传统上被认为是一种细胞外病原体。该特性可能有助于细菌持久性,保护免受抗生素侵害和逃避免疫防御。促成内在化的机制已被部分阐明,但在细胞内触发的细菌过程在很大程度上是未知的。
结果:我们开发了一种使用人肺上皮细胞的体外模型,该模型显示了长达2周的细胞内细菌持久性。使用原始方法,我们成功地收集并扩增了从感染的真核细胞中回收的少量细菌RNA。在两个内在化后的时间使用覆盖整个金黄色葡萄球菌基因组的寡核苷酸阵列进行转录组学分析,并将其与非内在化细菌的基因表达进行比较。在上皮细胞中金黄色葡萄球菌6850长时间内在化后,未观察到细胞死亡的迹象。内化后,观察到细菌基因表达的广泛改变。尽管主要的代谢途径(包括细胞分裂,营养物质运输和调节过程)被大幅下调,但许多与铁清除和毒力有关的基因却被上调。在最初的适应之后,是几种代谢功能的转录增加。但是,已知影响宿主细胞完整性的几种毒素基因的表达似乎受到严格限制。
结论:这些分子洞察力与表型观察结果相关,并证明金黄色葡萄球菌在感染后早期调节基因表达以促进存活。金黄色葡萄球菌似乎适合非吞噬细胞中的细胞内存活。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录