Program of Molecular Pathogenesis, Helen L and Martin S. Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, 540 First Avenue, New York City, NY 10016, USA.
Cell Microbiol. 2013 Jun;15(6):891-909. doi: 10.1111/cmi.12085. Epub 2012 Dec 24.
Staphylococcus (S.) aureus is a frequent cause of severe skin infections. The ability to control the infection is largely dependent on the rapid recruitment of neutrophils (PMN). To gain more insight into the dynamics of PMN migration and host-pathogen interactions in vivo, we used intravital two-photon (2-P) microscopy to visualize S. aureus skin infections in the mouse. Reporter S. aureus strains expressing fluorescent proteins were developed, which allowed for detection of the bacteria in vivo. By employing LysM-EGFP mice to visualize PMN, we observed the rapid appearance of PMN in the extravascular space of the dermis and their directed movement towards the focus of infection, which led to the delineation of an abscess within 1 day. Moreover, tracking of transferred labelled bone-marrow neutrophils showed that PMN localization to the site of infection is dependent on the presence of G-protein-coupled receptors on the PMN, whereas Interleukin-1 receptor was required on host cells other than PMN. Furthermore, the S. aureus complement inhibitor Ecb could block PMN accumulation at thesite of infection. Our results establish that 2-P microscopy is a powerful tool to investigate the orchestration of the immune cells, S. aureus location and gene expression in vivo on a single cell level.
金黄色葡萄球菌（S. aureus）是严重皮肤感染的常见原因。控制感染的能力在很大程度上取决于中性粒细胞（PMN）的快速募集。为了更深入地了解PMN 迁移和体内宿主-病原体相互作用的动态，我们使用活体双光子（2-P）显微镜观察小鼠皮肤金黄色葡萄球菌感染。开发了表达荧光蛋白的报告金黄色葡萄球菌菌株，这使得可以在体内检测到细菌。通过使用 LysM-EGFP 小鼠来可视化 PMN，我们观察到 PMN 在真皮的血管外空间中迅速出现，并向感染焦点定向移动，这导致在 1 天内划定脓肿。此外，追踪转导的标记骨髓中性粒细胞表明，PMN 定位于感染部位取决于 PMN 上 G 蛋白偶联受体的存在，而白细胞介素-1 受体除 PMN 之外的宿主细胞上是必需的。此外，金黄色葡萄球菌补体抑制剂 Ecb 可以阻止 PMN 在感染部位的积聚。我们的结果表明，2-P 显微镜是一种强大的工具，可以在单细胞水平上研究免疫细胞、金黄色葡萄球菌位置和基因表达的协调作用。
