PM2.5短期暴露人群外周血淋巴细胞MGMT甲基化修饰改变及其生物学意义

doi:10.3969/j.issn.1004-616x.2025.03.002

摘要/Abstract

摘要： 目的：筛查健康成人短期PM_2.5暴露后O6-甲基鸟嘌呤-DNA甲基转移酶基因(MGMT) 特异CpG位点甲基化修饰改变及其生物学意义。方法：在PM_2.5高污染地区河北石家庄市河北医科大学招募30名健康男性志愿者进行为期35 d的定组研究，基于个体时间-活动模式评估个体每日PM_2.5外暴露水平；分别在PM_2.5高、低暴露时间点下采集志愿者外周血，分离淋巴细胞提取DNA，采用焦磷酸测序法检测MGMT甲基化水平。同时定量分析尿1-羟基芘(1-OHP)、8-羟基-2′-脱氧鸟苷(8-OHdG)水平和血浆促炎细胞因子肿瘤坏死因子α(TNF-α)浓度，评估PM_2.5短期暴露对DNA氧化损伤和炎症反应的影响。结果：PM_2.5高暴露时间点前3天的环境PM_2.5平均浓度(110.09 μg/m³)是低暴露时间点(47.37 μg/m³)的2.32倍，PM_2.5内暴露水平指标尿1-OHP浓度是低暴露时间点的1.73倍(P<0.01)，尿8-OHdG和血浆TNF-α浓度分别是低暴露下的1.18倍和1.66倍(均为P<0.01)。PM_2.5高暴露时间点机体DNA氧化损伤和炎症反应增加的同时，MGMT CpG位点1、3、4、5、6、10的甲基化率分别下降37.31%、42.60%、19.69%、15.29%、34.95%和32.12%(均为P<0.05)；其中CpG位点1、3和10的低甲基化修饰不仅与PM_2.5内暴露水平1-OHP呈负相关(β≥-0.40，P<0.05)，还与DNA氧化损伤(β≥-0.46，P<0.05)和炎症反应(β≥-0.26，P<0.05)呈负相关。这些CpG热点甲基化修饰改变均与个体PM_2.5移动平均浓度呈负相关(β≥-0.53，P<0.05)。结论：MGMT基因低甲基化修饰CpG热点1、3和10，与PM_2.5内、外暴露和生物学效应均存在相关性，可作为人群PM_2.5暴露的潜在生物标志物。

关键词: 短期PM_2.5暴露, 定组研究, MGMT基因, DNA甲基化, 特异性CpG位点

Abstract: OBJECTIVE： This study aimed to screen for methylation changes at MGMT CpG sites and their biological significance in blood lymphocytes from healthy adults who were exposed to short-term PM_2.5. METHODS： Thirty healthy male undergraduates from Hebei Medical University participated in a 35-day panel study， during which daily PM_2.5 exposure was assessed based on individual time-activity patterns. MGMT methylation was quantified by pyrophosphate sequencing of DNA extracted from peripheral blood lymphocytes at low and high PM_2.5 exposure time points. Additionally， urinary 1-hydroxypyrene (1-OHP)， 8-hydroxy- 2'-deoxyguanosine (8-OHdG)， and plasma tumor necrosis factor-alpha (TNF-α) levels were analyzed. RESULTS： The average ambient PM_2.5 concentration for the three days before the high exposure (110.09 μg/m³) was 2.32 times higher than at low exposure (47.37 μg/m³)，while urinary 1-OHP levels，indicating internal exposure，were 1.73 times higher (P<0.01). Urinary 8-OHdG and plasma TNF-α levels were 1.18-fold and 1.66-fold higher，respectively，than those under low exposure (all P<0.01). Increase in oxidative DNA damage and inflammatory response was accompanied by a decrease in the methylation levels of MGMT CpG sites 1， 3，4，5，6，and 10 by 37.31%，42.60%，19.69%，15.29%，34.95% and 32.12%，respectively (all P<0.05). Hypomethylation at CpG sites 1，3，and 10 was negatively correlated with urinary 1-OHP (β≥-0.40，all P<0.05)，8-OHdG (β≥-0.46，all P<0.05)，and TNF-α (β≥-0.26，all P<0.05). Altered methylation at these hot CpG sites was negatively correlated with the moving average concentrations of PM_2.5 (lag0-2) (β≥-0.53，all P< 0.05). CONCLUSION： MGMT hypomethylation modifications at hot CpG sites 1，3 and 10 were found to be associated with both external and internal PM_2.5 exposure as well as biological effects，indicating their potential as biomarkers for PM_2.5 exposure in the population.

Key words: short-term PM_2.5 exposure, panel study, MGMT gene, DNA methylation, specific CpG sites

中图分类号:

R114

刘文洁, 叶丽珠, 蒋悦, 陈燊, 陈雯. PM_2.5短期暴露人群外周血淋巴细胞MGMT甲基化修饰改变及其生物学意义[J]. 癌变·畸变·突变, 2025, 37(3): 183-189.

LIU Wenjie, YE Lizhu, JIANG Yue, CHEN Shen, CHEN Wen. Altered MGMT methylation and biological significance in blood lymphocytes from short-term PM_2.5-exposed population[J]. Carcinogenesis, Teratogenesis & Mutagenesis, 2025, 37(3): 183-189.

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