金黄色葡萄球菌通过TLR2/PI3K信号诱导巨噬细胞的炎症反应和自噬

TLR2 modulates Staphylococcus aureus-induced inflammatory response and autophagy in macrophages through PI3K signaling pathway

目的探究巨噬细胞表面Toll样受体2(TLR2)在介导金黄色葡萄球菌(SA)诱导哮喘炎症反应中的分子机制。方法通过SA刺激小鼠RAW264.7巨噬细胞系建立炎症反应模型,分别用TLR2小干扰RNA(si RNA)和磷脂酰肌醇3激酶(PI3K)抑制剂3-甲基腺嘌呤(3-MA)处理。Western blot法检测细胞裂解液中TLR2、髓样分化因子88(My D88)、PI3K、核因子κBp65(NF-κBp65)磷酸化的NF-κBp65(p-NF-κBp65)以及自噬蛋白beclin-1和微管相关蛋白1轻链3B(LC3B)的水平,ELISA检测细胞上清液肿瘤坏死因子α(TNF-α)和白细胞介素6(IL-6)的分泌水平,激光共聚焦显微镜观察自噬溶酶体的数量。结果 SA刺激巨噬细胞活化TLR2等多种信号通路。TLR2 si RNA显著抑制PI3K、p-NF-κBp65以及自噬蛋白beclin-1和LC3B的表达,此外,自噬溶酶体的数量和TNF-α和IL-6的分泌也显著减少。3-MA在抑制自噬和炎症反应方面与TLR2 si RNA的作用效果相同。结论 TLR2通过PI3K信号通路调控金黄色葡萄球菌诱导巨噬细胞的炎症反应和自噬。

Objective To investigate the molecular mechanisms of Toll-like receptor 2（ TLR2） taking part in inflammatory response in Staphylococcus aureus（ SA）-induced asthma. Methods We established the cell inflammatory response model through stimulating mouse RAW264. 7 macrophages with SA. The TLR2, myeloid differentiation factor 88（ My D88）,phosphoinositide-3 kinase（ PI3 K）,nuclear factor κBp65（ NF-κBp65）,phospho-NF-κBp65,beclin-1 and microtubule-associated protein 1 light chain 3 B（ LC3 B） were detected by Western blot analysis after treatment with TLR2 smal interfering RNA（ si RNA） and 3-methyladenine（ 3-MA）,and the tumor necrosis factor α（ TNF-α） and interleukin 6（ IL-6） were determined by ELISA. In addition,the number of autolysosomes was observed by the laser scanning confocal microscope. Results SA-stimulated macrophages activated various signaling pathways including TLR2. TLR2 si RNA markedly repressed the expressions of PI3 K,phospho-NF-κBp65,the autophagy protein beclin-1 and LC3 B as well as the number of autolysosomes and the production of TNF-and IL-6. We also demonstrated that 3-MA had the same effect on autophagy and inflammation as TLR2 si RNA did. Conclusion TLR2 modulates SA-induced inflammatory response and autophagy in macrophages through PI3 K signaling pathway.