白细胞介素-4负调控NF-κB通路抑制炎症反应的机制研究

摘要：目的 探讨白细胞介素（IL）-4 对于脂多糖（LPS）诱导的 Ana-1 细胞髓样分化因子 88（MyD88）/核因子 （NF）-κB信号通路的影响。方法 将小鼠巨噬细胞Ana-1分为LPS组（给予50 μg/L LPS刺激）和LPS+IL-4组（10 μg/L IL-4预培养1 h后，给予LPS 刺激）。在0、0.5、1和2 h时收集细胞培养上清液。采用RT-PCR 检测MyD88和 NF-κB mRNA的相对表达水平；Western blot法检测MyD88、NF-κB总蛋白、NF-κB p65蛋白表达水平；ELISA法检测 NF-κB p65胞核/胞浆比例，以及细胞培养上清液中IL-6和肿瘤坏死因子（TNF）-α含量。结果 随着细胞培养时间 的延长，LPS组MyD88、NF-κB mRNA和蛋白表达水平，NF-κB p65胞核/胞浆比例，IL-6和TNF-α水平均呈逐渐升高 的趋势（P＜0.05）；而 LPS+IL-4 组 MyD88 mRNA 表达水平无明显变化（P＞0.05），MyD88 蛋白表达水平、NF-κB mRNA和蛋白表达水平、NF-κB p65胞核/胞浆比例、IL-6和TNF-α水平则均呈先升高后降低的趋势（P＜0.05）；LPS+ IL-4组MyD88 mRNA和蛋白表达水平、NF-κB p65胞核/胞浆比例、IL-6和TNF-α水平在1 h和2 h时显著低于LPS组 （P＜0.05），而2组不同时间点NF-κB mRNA和蛋白表达水平比较差异均无统计学意义（P＞0.05）。结论 IL-4发挥 抗炎作用可能与抑制MyD88/NF-κB信号通路活化有关，IL-4可下调促炎细胞因子IL-6和TNF-α的表达。

Mechanism of interleukin-4 negatively regulating NF-κB pathway to inhibit inflammatory response

Abstract: Objective To investigate the effect of interleukin (IL) -4 on MyD88/NF-κB signaling pathway in Ana-1 cells induced by lipopolysaccharides (LPS). Methods The mouse macrophages Ana-1 were divided into LPS group (given 50 μg/L LPS stimulation) and LPS+IL-4 group (given LPS stimulation after 10 μg/L IL-4 pre-culture for 1 hour). Cell culture supernatants were collected at 0, 0.5, 1 and 2 hours. The relative expression levels of MyD88 and NF-κB mRNA were detected by RT-PCR. The expression levels of MyD88, total protein of NF - κB and NF - κB p65 were detected by Western blot assay. The content ratio in nucleus and cytoplasm of NF-κB p65 and the contents of interleukin (IL)-6 and tumor necrosis factor (TNF)-α in cell culture supernatant were detected by ELISA. Results With the prolongation of cell culture time, the expression levels of MyD88 and NF-κB mRNA and proteins, the ratio of NF-κB p65 nuclei/cytoplasm, IL- 6 and TNF-a levels increased gradually (P＜0.05). There was no significant difference in the expression of MyD88 in LPS+ IL-4 group (P＞0.05). The expression of MyD88 protein, NF-κB mRNA and protein, the nuclear/cytoplasmic ratio of NF- κB p65 and levels of IL-6 and TNF-α increased first and then decreased (P＜0.05). The expression of MyD88 protein, the nuclear/cytoplasmic ratio of NF-κB p65 and levels of IL-6 and TNF-α at 1 h and 2 h were significantly decreased in LPS+ IL-4 group than those of LPS group (P＜0.05). There were no significant differences in the expression levels of NF- κB mRNA and proteins in different time points between two groups (P＞0.05). Conclusion IL-4 may play an antiinflammatory role by inhibiting the activation of MyD88/NF-κB signaling pathway. IL-4 can down-regulate the expression of pro-inflammatory cytokines IL-6 and TNF-α.