Epigenetic signatures of phthalate exposure and potential risks: a DNA methylation analysis using Infinium MethylationEPIC BeadChip

Phthalates are common environmental pollutants known to disrupt various regulatory systems and are associated with several health issues, such as impaired immune response, developmental toxicity, hormonal disruption, and type 2 diabetes. Epigenetic modifications, such as DNA methylation, can serve as early indicators of environmental toxicant exposure due to their rapid alteration in response to varying environmental factors without altering the underlying DNA sequence. To investigate the impact of phthalate exposure on human health and the affected regulatory mechanisms, this study analysed a DNA methylation dataset generated using the Illumina Infinium MethylationEPIC BeadChip (EPIC BeadChip) array, along with the concentrations of 15 urinary phthalate metabolites from 389 participants. The results revealed sex-specific differences in phthalate concentrations, with females exhibiting relatively higher levels than males. These differences may reflect a combination of factors, including lifestyle behaviours and potential differences in exposure sources. Furthermore, differentially methylated CpG sites (DMCs) were identified only in the mono-ethylhexyl phthalate (MEHP) dataset, where a total of 53 DMCs were detected, including 11 that were consistently detected across multiple MEHP concentration comparisons. Additionally, the functional analysis showed that these DMCs are primarily involved in protein and nucleotide binding, immune response, ion channel regulation, and membrane-associated pathways. This study provides high-potential phthalate-related methylation markers, their associated genes, and the functions they are involved in. These findings offer valuable insights for the research on environmental toxicants and epigenetics, while supporting clinical applications related to phthalates.