Further Insight into the Mechanism of Human PMN Lysis following Phagocytosis of Staphylococcus aureus.
Further Insight into the Mechanism of Human PMN Lysis following Phagocytosis of Staphylococcus aureus.
复制标题
在金黄色葡萄球菌吞噬作用后，进一步了解了人类PMN裂解的机制。
DOI：
10.1128/spectrum.00888-21
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发表时间：
2021-10-31
影响因子：
3.7
通讯作者：
DeLeo FR
中科院分区：
文献类型：
--
作者：
Rungelrath V;Porter AR;Malachowa N;Freedman BA;Leung JM;Voyich JM;Otto M;Kobayashi SD;DeLeo FR
金黄色葡萄球菌是一种重要的人类病原体，可导致从轻微的浅表皮肤感染到坏死性肺炎、心内膜炎和败血症等危及生命的各种疾病。中性粒细胞(PMN，特别是中性粒细胞)对于宿主抵御金黄色葡萄球菌感染是必不可少的，而且微生物很容易被吞噬。大多数摄入的细菌都会被杀死，但一些金黄色葡萄球菌菌株--如流行的USA300菌株--吞噬后引起PMN裂解的能力增强。虽然已经取得了进展，但金黄色葡萄球菌吞噬后的裂解机制仍不完全确定。在这里，我们验证了一种假设，即在PMN溶解之前，吞噬小体的完整性被破坏，金黄色葡萄球菌从PMN吞噬小体逃逸到细胞质中。我们使用USA300野生型和等基因缺失菌株来评估和/或验证选定的金黄色葡萄球菌分子在这一细胞溶解过程中的作用。与野生型USA300菌株相比，ΔagR、ΔHla、ΔlukGH和ΔPSM菌株在吞噬后3小时和/或6小时对人PMN的裂解显著减少，这与之前的研究一致。最值得注意的是，共聚焦显微镜结合选择性通透性分析表明，吞噬体膜的完整性在金黄色葡萄球菌吞噬后的PMN裂解之前基本保持不变。我们得出结论，中性粒细胞裂解不需要金黄色葡萄球菌从吞噬小体逃逸到细胞质，这些都是独立的现象。这一发现与金黄色葡萄球菌(通过选定的分子)通过一种未知的信号机制触发人PMN裂解的能力是一致的。重要信息金黄色葡萄球菌USA300菌株具有在吞噬后引起人中性粒细胞快速溶解的能力。尽管这一现象可能有助于USA300作为一种人类病原体的成功，但我们对其机制的了解仍然不完整。在这里，我们使用选择性通透性分析结合共聚焦显微镜来证明USA300包含在人中性粒细胞吞噬小体中，直到宿主细胞裂解。因此，与巨噬细胞的过程一致，金黄色葡萄球菌在细胞溶解之前未能逃脱到中性粒细胞细胞质中。
Staphylococcus aureus is an important human pathogen that can cause a variety of diseases ranging from mild superficial skin infections to life-threatening conditions like necrotizing pneumonia, endocarditis, and septicemia. Polymorphonuclear leukocytes (PMNs; neutrophils in particular herein) are essential for host defense against S. aureus infections, and the microbe is phagocytosed readily. Most ingested bacteria are killed, but some S. aureus strains—such as the epidemic USA300 strain—have an enhanced ability to cause PMN lysis after phagocytosis. Although progress has been made, the mechanism for lysis after phagocytosis of S. aureus remains incompletely determined. Here, we tested the hypothesis that disruption of phagosome integrity and escape of S. aureus from the PMN phagosome into the cytoplasm precedes PMN lysis. We used USA300 wild-type and isogenic deletion strains to evaluate and/or verify the role of selected S. aureus molecules in this cytolytic process. Compared to the wild-type USA300 strain, Δagr, Δhla, ΔlukGH, and Δpsm strains each caused significantly less lysis of human PMNs 3 h and/or 6 h after phagocytosis, consistent with previous studies. Most notably, confocal microscopy coupled with selective permeabilization assays demonstrated that phagosome membrane integrity is largely maintained prior to PMN lysis after S. aureus phagocytosis. We conclude that PMN lysis does not require escape of S. aureus from the phagosome to the cytoplasm and that these are independent phenomena. The findings are consistent with the ability of S. aureus (via selected molecules) to trigger lysis of human PMNs by an undetermined signaling mechanism. IMPORTANCE S. aureus strain USA300 has the ability to cause rapid lysis of human neutrophils after phagocytosis. Although this phenomenon likely contributes to the success of USA300 as a human pathogen, our knowledge of the mechanism remains incomplete. Here, we used a selective permeabilization assay coupled with confocal microscopy to demonstrate that USA300 is contained within human neutrophil phagosomes until the point of host cell lysis. Thus, consistent with a process in macrophages, S. aureus fails to escape into the neutrophil cytoplasm prior to cytolysis.