Staphylococcus aureus is a major cause of prosthetic joint infection (PJI), which is characterized by biofilm formation. S. aureus biofilm skews the host immune response toward an anti-inflammatory profile by the increased recruitment of myeloid-derived suppressor cells (MDSCs) that attenuate macrophage proinflammatory activity, leading to chronic infection. A screen of the Nebraska Transposon Mutant Library identified several hits in the ATP synthase operon that elicited a heightened inflammatory response in macrophages and MDSCs, including atpA, which encodes the alpha subunit of ATP synthase. An atpA transposon mutant (ΔatpA) had altered growth kinetics under both planktonic and biofilm conditions, along with a diffuse biofilm architecture that was permissive for leukocyte infiltration, as observed by confocal laser scanning microscopy. Coculture of MDSCs and macrophages with ΔatpA biofilm elicited significant increases in the proinflammatory cytokines interleukin 12p70 (IL-12p70), tumor necrosis factor alpha (TNF-α), and IL-6. This was attributed to increased leukocyte survival resulting from less toxin and protease production by ΔatpA biofilm as determined by liquid chromatography with tandem mass spectrometry (LC-MS/MS). The enhanced inflammatory response elicited by ΔatpA biofilm was cell lysis-dependent since it was negated by polyanethole sodium sulfanate treatment or deletion of the major autolysin, Atl. In a mouse model of PJI, ΔatpA-infected mice had decreased MDSCs concomitant with increased monocyte/macrophage infiltrates and proinflammatory cytokine production, which resulted in biofilm clearance. These studies identify S. aureus ATP synthase as an important factor in influencing the immune response during biofilm-associated infection and bacterial persistence.

中文翻译：

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金黄色葡萄球菌 ATP 合酶通过影响先天免疫促进生物膜持久性。


金黄色葡萄球菌是假体关节感染 (PJI) 的主要原因，其特点是形成生物膜。金黄色葡萄球菌生物膜通过增加骨髓源性抑制细胞（MDSC）的募集而使宿主免疫反应偏向抗炎模式，从而减弱巨噬细胞促炎活性，从而导致慢性感染。内布拉斯加州转座子突变体库的筛选发现了 ATP 合酶操纵子中的几个命中点，这些命中点在巨噬细胞和 MDSC 中引发了增强的炎症反应，其中包括编码 ATP 合酶 α 亚基的atpA 。通过共焦激光扫描显微镜观察到， atpA转座子突变体 (Δ atpA ) 在浮游和生物膜条件下都改变了生长动力学，并且具有允许白细胞浸润的弥漫生物膜结构。 MDSC 和巨噬细胞与 Δ atpA生物膜共培养可引起促炎细胞因子白细胞介素 12p70 (IL-12p70)、肿瘤坏死因子 α (TNF-α) 和 IL-6 显着增加。这是由于 Δ atpA生物膜产生的毒素和蛋白酶减少导致白细胞存活率增加，如液相色谱串联质谱法 (LC-MS/MS) 所测定的。 Δ atpA生物膜引起的增强炎症反应是细胞裂解依赖性的，因为它可以通过聚茴香脑硫酸钠处理或删除主要自溶素 Atl 来消除。在 PJI 小鼠模型中，Δ atpA感染的小鼠 MDSC 减少，同时单核细胞/巨噬细胞浸润和促炎细胞因子产生增加，从而导致生物膜清除。 这些研究确定金黄色葡萄球菌ATP 合酶是影响生物膜相关感染和细菌持久性期间免疫反应的重要因素。