颗粒物和CD4^+T淋巴细胞IFN-γDNA甲基化在儿童变应性鼻炎发病中的机制研究

The study of atmospheric particulate matters and IFN-γDNA methylation in CD4^+ T cells from patients with AR children

目的:探讨大气污染环境对AR儿童CD4+TIFN-γ基因启动子区域甲基化的表观遗传调控及相关转录水平表达的影响。方法:对35例6~12岁确诊为持续性AR患儿进行随访,收集患儿血样及设立匹配30例为正常对照组,均进行IFN-γ基因启动子区域的甲基化克隆测序并使用实时定量逆转录聚合酶链反应检测其mRNA表达水平。根据上海市环境局提供的PM10和PM2.5数据,结合居住地址和气象监测点经纬度资料,利用克里格插值法,同时使用上海地区颗粒物穿透率系数模型和儿童室内外活动时间的调查,对PM2.5和PM10的个人综合暴露评估。结果:AR组CD4+T淋巴细胞中IFN-γ基因启动子区域平均甲基化水平明显高于对照组(P<0.05);其中位点-299、+119、+168甲基化程度有差异(P=0.004,P=0.029,P=0.035);AR组IFN-γ转录水平明显降低(P<0.05),并与其平均DNA甲基化水平呈负性相关(r=-0.341,P<0.01)。校正后AR患儿长期暴露的颗粒物PM2.5浓度与其IFN-γ基因启动子区域甲基化程度呈正相关(β=1.441,SD=0.672,P<0.05)。结论:AR患儿IFN-γ基因启动子区域甲基化高水平可能受到PM2.5的影响。

Objective：To investigate the possible effects of meteorological and environmental factors on AR of children and IFN-γgene specific DNA methylation levels in CD4＋T cells of patients with AR.Method：Undergoing follow-up on 35 pediatric AR patients（6-12years）.Data on daily sulfur dioxide（SO2）,nitrogen dioxide（NO2）,particulate matter of diameter smaller than 10 micrometer（PM10）and particulate matter of diameter smaller than2.5micrometer（PM2.5）,the average of ozone（O3）per 8hours was available as average values derived from the data of 6state-controlled monitoring stations distributed across Pudong district,Shanghai.We quantified IFN-γ（interferon-γ）gene specific DNA methylation levels in CD4＋T cells from 35 patients with AR and 30 healthy controls.mRNA levels of IFN-γgene were measured by real-time reverse transcriptase-PCR.Methods of personal exposure assessment of PM2.5and PM10 were measured.Result：Compared with control,IFN-γpromoter region was hypermethylated in AR CD4＋T cells（P〈0.05）.Of all observed CpG sites in IFN-γpromoter region,there were significant differences in CpG-299,CpG＋119,CpG＋168（P=0.004,P=0.029,P=0.035）.IFN-γmRNA expression was significantly increase in CD4＋T cells（P〈0.05）.The level of IFN-γmRNA expression was negatively correlated to mean level of methylation in IFN-γpromoter region.After adjusting,level of long exposure PM2.5 was positively correlated with level of methylation in IFN-γpromoter region.Conclusion：Level of methylation in IFN-γpromoter region may be affected by long exposure PM2.5.