Epigenetic Effects of Exposure to Insecticide on Early Differentiation of Mouse Embryonic Stem Cells

Abstract

Increasing evidence indicates that insecticides induce various diseases via DNA methylation. DNA methylation plays an important role during cell differentiation and exhibits its greatest vulnerability to environmental factors during embryogenesis. Therefore, it is important to evaluate the effects on DNA methylation at the early stage of cell differentiation to understand developmental toxicity. However, DNA methylation induced by insecticides and the associated effects on cell differentiation are unclear. In this research, we introduced a high-content approach utilizing mouse embryonic stem cells harboring enhanced green fluorescent protein fused with methyl CpG-binding protein to evaluate global DNA methylation induced by various insecticides. DNA methylation was assessed in 22 genes after pesticide exposure to investigate the relationships with biological processes such as cell cycle, cell apoptosis, and cell differentiation. Exposure to acetamiprid, imidacloprid, carbaryl, and o,p'-DDT increased the granular intensity, indicating their global DNA-methylating effects. Exposure to imidacloprid decreased DNA methylation in genes such as Cdkn2a, Dapk1, Cdh1, Mlh1, Timp3, and Rarb, indicating the potential influence of the DNA methylation pattern on cell differentiation. We developed a promising approach for evaluating global DNA methylation, and our findings suggested that imidacloprid might exhibit developmental effects through DNA methylation pattern.