Department of Toxicology, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China.
Department of Toxicology, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China; Boji Drug Evaluation Center, Boji Medical Technology Co., Ltd, Guangzhou, China.
Environ Int. 2024 Apr;186:108645. doi: 10.1016/j.envint.2024.108645. Epub 2024 Apr 10.
Benzene is a broadly used industrial chemicals which causes various hematologic abnormalities in human. Altered DNA methylation has been proposed as epigenetic biomarkers in health risk evaluation of benzene exposure, yet the role of methylation at specific CpG sites in predicting hematological effects remains unclear. In this study, we recruited 120 low-level benzene-exposed and 101 control male workers from a petrochemical factory in Maoming City, Guangdong Province, China. Urinary S-phenylmercapturic acid (SPMA) in benzene-exposed workers was 3.40-fold higher than that in control workers (P < 0.001). Benzene-induced hematotoxicity was characterized by reduced white blood cells counts and nuclear division index (NDI), along with an increased DNA damage and urinary 8-hydroxy-2'-deoxyguanosine (all P < 0.05). Methylation levels of TRIM36, MGMT and RASSF1a genes in peripheral blood lymphocytes (PBLCs) were quantified by pyrosequencing. CpG site 6 of TRIM36, CpG site 2, 4, 6 of RASSF1a and CpG site 1, 3 of MGMT methylation were recognized as hot CpG sites due to a strong correlation with both internal exposure and hematological effects. Notably, integrating hot CpG sites methylation of multiple genes reveal a higher efficiency in prediction of integrative damage compared to individual genes at hot CpG sites. The negative dose-response relationship between the combined methylation of hot CpG sites in three genes and integrative damage enabled the classification of benzene-exposed individuals into high-risk or low-risk groups using the median cut-off value of the integrative index. Subsequently, a prediction model for integrative damage in benzene-exposed populations was built based on the methylation status of the identified hot CpG sites in the three genes. Taken together, these findings provide a novel insight into application prospect of specific CpG site methylation as epi-biomarkers for health risk assessment of environmental pollutants.
苯是一种广泛使用的工业化学品，会导致人类出现各种血液异常。已提出 DNA 甲基化改变作为苯暴露健康风险评估的表观遗传生物标志物，但特定 CpG 位点的甲基化在预测血液学效应中的作用尚不清楚。在这项研究中，我们从广东省茂名市一家石化厂招募了 120 名低水平苯暴露男性工人和 101 名对照男性工人。苯暴露工人的尿 S-苯巯基尿酸（SPMA）水平是对照组的 3.40 倍（P<0.001）。苯引起的血液毒性表现为白细胞计数和核分裂指数（NDI）降低，同时 DNA 损伤和尿液 8-羟基-2'-脱氧鸟苷（均 P<0.05）增加。通过焦磷酸测序定量检测外周血淋巴细胞（PBLCs）中 TRIM36、MGMT 和 RASSF1a 基因的甲基化水平。TRIM36 的 CpG 位点 6、RASSF1a 的 CpG 位点 2、4、6 和 MGMT 的 CpG 位点 1、3 由于与内部暴露和血液学效应均具有很强的相关性，被认为是热点 CpG 位点。值得注意的是，整合多个基因的热点 CpG 位点甲基化在预测综合损伤方面比单个基因的热点 CpG 位点具有更高的效率。三个基因的热点 CpG 位点联合甲基化与综合损伤之间的负剂量-反应关系使得可以使用综合指数的中位数截断值将苯暴露个体分为高危或低危组。随后，基于三个基因中鉴定的热点 CpG 位点的甲基化状态，建立了苯暴露人群综合损伤的预测模型。总之，这些发现为特定 CpG 位点甲基化为环境污染物健康风险评估的表观遗传生物标志物的应用前景提供了新的见解。
