Genome-wide analysis of histone trimethylation reveals a global impact of bisphenol A on telomeric binding proteins and histone acetyltransferase factors: Complementing in vitro and human data from the INMA cohort.

Abstract

Abstract Objective: To assess the genetic and epigenetic effects promoted by Bisphenol A(BPA) exposure in adolescent males from the Spanish INMA-Granada birth cohort, as well as in human cells. Methods: DNA methylation was analysed using MEDIP. Repeat number variation in genomic DNA was evaluated, along with the analysis of H3K4me3 by using chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq). All experiments were performed with material extracted from whole blood of adolescents from INMA. The epidemiological study was complemented by in vitro assessments of human (HeLa) cells exposed to BPA, specifically, immunofluorescence evaluation of histone modification levels, gene expression analysis and ChIP‒qPCR analysis. Results: Adolescents in the high urinary BPA group presented higher genetic instability of Satellite A (SATA) repetitive region compared to those in the low BPA group. We also observed decreased DNA methylation at the promoters of the imprinted genes H19, KCNQ1, and IGF2; at LINE1 retroelements; and at the ARID2, EGFR1 and ESRRA genes. Genome-wide sequencing revealed increased H3K4me3 occupancy at the promoters of genes encoding histone acetyltransferases, telomeric DNA binding factors and DNA repair genes. These results were supported by studying HeLa cells exposed to 10 nMBPA in vitro. Exposure of cells to BPA caused a global increase in histone H4 acetylation and a decrease in H3K9me3 levels. In exposed cells, changes in the expression of genes encoding DNA repair factors (ATM, ARID2) were observed, and the expression of several genesencoding telomeric DNA binding factors (SMG7, TERT, TEN1, UPF1, ZBTB48) increased. Moreover, increased binding of ESR1 to KAT5, KMT2E and TERF2IP promoters and decreased ESR1 binding at the RARA promoter were observed. Conclusion: Genome-wide analysis of histone trimethylation and BPA exposure in the in adolescents from the INMA cohort revealed a global impact of BPA on the expression of genes encoding telomeric binding proteins and histone acetyltransferase factors, which showed parallels with HeLa cells exposed to a human-relevant dose.