Institute for Clinical Research, Mie National Hospital, Mie, Japan.
J Leukoc Biol. 2012 Aug;92(2):333-41. doi: 10.1189/jlb.0112009. Epub 2012 May 17.
Colonization by SA is associated with exacerbation of AD. Eosinophilic inflammation is a cardinal pathological feature of AD, but little is known about possible direct interaction between SA and eosinophils. PAFR appears to be involved in phagocytosis of Gram-positive bacteria by leukocytes. The objective of this study was to investigate whether SA directly induces eosinophil effector functions via PAFR in the context of AD pathogenesis. Peripheral blood eosinophils were cultured with heat-killed SA, and EDN release, superoxide generation, and adhesion to fibronectin-coated plates were measured. Cytokines, released in the supernatants, were quantified by multiplex bead immunoassays. FISH-labeled SA was incubated with eosinophils and visualized by confocal laser-scanning microscopy. PAFR-blocking peptide and PAFR antagonists were tested for inhibitory effects on SA-induced reactions. SA induced EDN release and superoxide generation by eosinophils in a dose-dependent manner. IL-5 significantly enhanced SA-induced EDN release. IL-5 and IL-17A significantly enhanced SA-induced superoxide generation. SA enhanced eosinophil adhesion to fibronectin, which was blocked by anti-CD49d, and induced eosinophil secretion of various cytokines/chemokines (IL-2R, IL-9, TNFR, IL-1 β, IL-17A, IP-10, TNF-α, PDGF-bb, VEGF, and FGF-basic). After incubation of eosinophils with SA, FISH-labeled SA was visualized in the eosinophils' cytoplasm, indicating phagocytosis. A PAFR-blocking peptide and two PAFR antagonists completely inhibited those reactions. In conclusion, SA directly induced eosinophil activation via PAFR. Blockade of PAFR may be a novel, therapeutic approach for AD colonized by SA.
金黄色葡萄球菌（SA）定植与 AD 恶化有关。嗜酸性粒细胞炎症是 AD 的主要病理特征，但对于 SA 与嗜酸性粒细胞之间可能存在的直接相互作用知之甚少。PAFR 似乎参与了白细胞吞噬革兰氏阳性菌的过程。本研究旨在探讨 SA 是否通过 PAFR 在 AD 发病机制中直接诱导嗜酸性粒细胞效应功能。用热灭活的 SA 培养外周血嗜酸性粒细胞，测量 EDN 释放、超氧化物生成和黏附在纤维连接蛋白包被的平板上的情况。通过多重珠免疫分析测定上清液中释放的细胞因子。用 FISH 标记的 SA 孵育嗜酸性粒细胞，并用共聚焦激光扫描显微镜观察。用 PAFR 阻断肽和 PAFR 拮抗剂测试其对 SA 诱导反应的抑制作用。SA 以剂量依赖的方式诱导嗜酸性粒细胞释放 EDN 和生成超氧化物。IL-5 显著增强了 SA 诱导的 EDN 释放。IL-5 和 IL-17A 显著增强了 SA 诱导的超氧化物生成。SA 增强了嗜酸性粒细胞对纤维连接蛋白的黏附，这一过程被抗 CD49d 阻断，并诱导嗜酸性粒细胞分泌各种细胞因子/趋化因子（IL-2R、IL-9、TNFR、IL-1β、IL-17A、IP-10、TNF-α、PDGF-bb、VEGF 和 FGF-basic）。在将嗜酸性粒细胞与 SA 孵育后，在嗜酸性粒细胞的细胞质中观察到 FISH 标记的 SA，表明发生了吞噬作用。PAFR 阻断肽和两种 PAFR 拮抗剂完全抑制了这些反应。总之，SA 通过 PAFR 直接诱导嗜酸性粒细胞活化。阻断 PAFR 可能是治疗金黄色葡萄球菌定植的 AD 的一种新的治疗方法。
