Department of Physiology, Immunology Laboratory, University of Calcutta, University Colleges of Science and Technology, Calcutta, West Bengal, India.
Scand J Immunol. 2014 Aug;80(2):127-43. doi: 10.1111/sji.12195.
Effects of blocking toll-like receptor-2 (TLR-2) on the survival of Staphylococcus aureus (S. aureus) and cytokine production in peritoneal macrophages of Swiss albino mice were analysed. Macrophages were infected with S. aureus in the presence and absence of anti-TLR-2 antibody. Tumour necrosis factor-α (TNF-α) interleukin-6 (IL-6), interferon-gamma (IFN-γ), interleukin-1β (IL-1β), interleukin-12 (IL-12) and interleukin-10 (IL-10) concentrations were measured. Expressions of TLR-2, NF-κB, MyD 88 were analysed by Western Blot. Expression of TLR-2 was increased in S. aureus-infected macrophages with respect to control and was MyD 88 independent. TLR2 blocking significantly reduced TNF-α, IL-6, IL-1β and IL-10 and increased IFN-γ and IL-12 production. Decreased catalase activity and increased superoxide dismutase (SOD) by S. aureus with concomitant increase in H2 O2 and nitric oxide (NO) were observed in the case of prior TLR-2 blocking. To understand whether catalase contributing in the intracellular survival, was of bacterial origin or not, 3-amino, 1, 2, 4-triazole (ATZ) was used to inhibit specifically macrophage-derived catalase. Catalase enzyme activity from the whole staphylococcal cells in the presence of ATZ suggested that the released catalase were of extracellular origin. From the intracellular survival assay, it was evident that pretreatment of macrophages with ATZ reduces the bacterial burden in macrophages when infected with the recovered bacteria only from the anti-TLR-2 antibody-treated macrophages after phagocytosis. Catalase protein expression from the whole staphylococcal cells recovered after phagocytosis also indicated the catalase release from S. aureus. Capturing of S. aureus via TLR-2 induces inflammatory reactions through activation of NF-κB-signalling pathways which was MyD88-independent.
分析了阻断 Toll 样受体-2(TLR-2)对金黄色葡萄球菌(S. aureus)在瑞士白化小鼠腹腔巨噬细胞中存活和细胞因子产生的影响。在存在和不存在抗 TLR-2 抗体的情况下,用 S. aureus 感染巨噬细胞。测量肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)、干扰素-γ(IFN-γ)、白细胞介素-1β(IL-1β)、白细胞介素-12(IL-12)和白细胞介素-10(IL-10)的浓度。通过 Western Blot 分析 TLR-2、NF-κB、MyD88 的表达。与对照相比,S. aureus 感染的巨噬细胞中 TLR-2 的表达增加,并且与 MyD88 无关。TLR2 阻断显著降低 TNF-α、IL-6、IL-1β 和 IL-10 的产生,增加 IFN-γ 和 IL-12 的产生。在 TLR-2 阻断之前,观察到 S. aureus 降低了过氧化氢酶的活性,增加了超氧化物歧化酶(SOD),同时增加了 H2O2 和一氧化氮(NO)的产生。为了了解过氧化氢酶是否有助于细菌的胞内存活,是来自细菌还是其他来源,使用 3-氨基-1,2,4-三唑(ATZ)来特异性抑制巨噬细胞衍生的过氧化氢酶。在存在 ATZ 的情况下,从整个金黄色葡萄球菌细胞中提取的过氧化氢酶酶活性表明,释放的过氧化氢酶来自细胞外。从细胞内存活实验中可以看出,在用 ATZ 预处理巨噬细胞后,在用从抗 TLR-2 抗体处理的巨噬细胞中回收的细菌感染时,仅从回收的细菌感染时,巨噬细胞中的细菌负荷减少。从吞噬作用后回收的整个金黄色葡萄球菌细胞中提取的过氧化氢酶蛋白表达也表明,金黄色葡萄球菌从细胞内释放了过氧化氢酶。金黄色葡萄球菌通过 TLR-2 的捕获通过 NF-κB 信号通路的激活诱导炎症反应,该通路与 MyD88 无关。