Short-term personal PM2.5 exposure and change in DNA methylation of imprinted genes: Panel study of healthy young adults in Guangzhou city, China

DNA methylation (DNAm) plays a significant role in deleterious health effects inflicted by fine particulate matter (PM₂.₅) on the human body. Recent studies have reported that DNAm of imprinted control regions (ICRs) in imprinted genes may be a sensitive biomarker of environmental exposure. Less is known about specific biomarkers of imprinted genes after PM₂.₅ exposure. The relationship between PM₂.₅ and its chemical constituents and DNAm of ICRs in imprinted genes after short-term exposure was investigated to determine specific human biomarkers of its adverse health effects. A panel study was carried out in healthy young people in Guangzhou, China. Mixed-effects models were used to evaluate the influence of PM₂.₅ and its constituent exposure on DNAm while controlling for potential confounders. There was no significant correlation between DNAm and personal PM₂.₅ exposure mass. DNAm changes in eight ICRs (L3MBTL1, NNAT, PEG10, GNAS Ex1A, MCTS2, SNURF/SNRPN, IGF2R, and RB1) and a non-imprinted gene (CYP1B1) were significantly associated with PM₂.₅ constituents. Compared to non-imprinted genes, imprinted gene methylation was more susceptible to interference with PM₂.₅ constituent exposure. Among those genes, L3MBTL1 was the most sensitive to personal PM₂.₅ constituent exposure. Moreover, transition metals derived from traffic sources (Cd, Fe, Mn, and Ni) significantly influenced DNAm of the imprinted genes, suggesting the importance of more targeted measures to reduce toxic constituents. Bioinformatics analysis indicated that imprinted genes (RB1) may be correlated with pathways and diseases (non-small cell lung cancer, glioma, and bladder cancer). The present study suggests that screening the imprinted gene for DNAm can be used as a sensitive biomarker of PM₂.₅ exposure. The results will provide data for prevention of PM₂.₅ exposure and a novel perspective on potential mechanisms on an epigenetic level.