Obesogen effect of bisphenol S alters mRNA expression and DNA methylation profiling in male mouse liver.

Environmental pollution is increasingly considered an important factor involved in the obesity incidence. Endocrine disruptors (EDs) are important actors in the concept of DOHaD (Developmental Origins of Health and Disease), where epigenetic mechanisms play crucial roles. Bisphenol A (BPA), a monomer used in the manufacture of plastics and resins is one of the most studied obesogenic endocrine disruptor. Bisphenol S (BPS), a BPA substitute, has the same obesogenic properties, acting at low doses with a sex-specific effect following perinatal exposure. Since the liver is a major organ in regulating body lipid homeostasis, we investigated gene expression and DNA methylation under low-dose BPS exposure. The BPS obesogenic effect was associated with an increase of hepatic triglyceride content. These physiological disturbances were accompanied by genome-wide changes in gene expression (1366 genes significantly modified more than 1.5-fold). Gene ontology analysis revealed alteration of gene cascades involved in protein translation and complement regulation. It was associated with hepatic DNA hypomethylation in autosomes and hypermethylation in sex chromosomes. Although no systematic correlation has been found between gene repression and hypermethylation, several genes related to liver metabolism were either hypermethylated (Acsl4, Gpr40, Cel, Pparδ, Abca6, Ces3a, Sgms2) or hypomethylated (Soga1, Gpihbp1, Nr1d2, Mlxipl, Rps6kb2, Esrrb, Thra, Cidec). In specific cases (Hapln4, ApoA4, Cidec, genes involved in lipid metabolism and liver fibrosis) mRNA upregulation was associated with hypomethylation. In conclusion, we show for the first time wide disruptive physiological effects of low-dose of BPS, which raises the question of its harmlessness as an industrial substitute for BPA.