肿瘤坏死因子α、干扰素γ刺激对肺泡巨噬细胞表面主要模式识别受体表达的影响

目的观察脓毒症主要相关细胞因子肿瘤坏死因子α(TNFα)和干扰素γ(IFNγ)对巨噬细胞表面主要模式识别受体(PRRs)表达的影响。方法分离培养小鼠肺泡巨噬细胞,用TNFα、IFNγ(终浓度均为20ng/ml)分别刺激细胞3h、6h、12h,通过逆转录聚合酶链反应和免疫组织化学检测细胞内PRRs,包括白细胞分化抗原14(CD14)、Toll样受体4(TLR4)、清道夫受体(SR)、细菌脂蛋白受体TLR2和细菌DNA受体TLR9mRNA表达及其蛋白表达。结果TNFα和IFNγ表现为不同程度地上调与炎细胞激活作用有关的PRRs(CD14、TLR2、TLR9)(P<0.05),下调与炎细胞防御作用有关的SR(P<0.05),而对TLR4基因及蛋白表达无显著刺激作用(P>0.05)。结论效应细胞释放的促炎因子TNFα、IFNγ能从基因转录和蛋白水平上对细胞表面PRRs产生明显的反馈调控作用,对于促进失控性炎症反应的发生具有一定病理生理意义。

The effects of TNF alpha and IFN gamma on the expression of pattern recognition receptors on the surface of mouse alveolar macrophages

Objective To investigate the effects of tumor necrosis factor alpha (TNF alpha) and interferon gamma (IFN gamma) on the expression of pattern recognition receptors (PRRs) on the surface of mouse alveolar macrophages. Methods Alveolar macrophages from mouse were cultured in DMEM supplemented with 10% (V/V) endotoxin-free calf serum. After the alveolar macrophages were stimulated with TNF alpha and IFN gamma (concentration, 20 ng/ml ) for 3 h, 6 h and 12 h, the expression of PRRs, including cluster of differentiation 14(CD14), scavenger receptor (SR), toll-like receptor 4 (TLR4), TLR2 and TLR9 mRNA and proteins were examined by RT-PCR and immunohistochemistry. Results The expressions of CD14, TLR2 and TLR9 receptors, which were related with cellular activation,were up-regulated by the stimulation of TNF alpha and IFN gamma(P<0.05), while SR, which was related with cellular defense action, was down-regulated(P<0.05).Although the expression of TLR4 was up-regulated, there was no statistical significance(P>0.05). Conclusions The cytokines such as TNF alpha and IFN gamma could also produce feedback regulation on the expression of PRRs at the levels of genes and proteins. Such regulation on the PRRs expression would be significant for further amplification of inflammation cascade and eventually leading to uncontrolled inflammation.