Tracing the epigenetic trajectory of EDC toxicity: Maternal BPAF drives uterine injuries via DNA methylation reprogramming.

Uterine development can be disrupted by endocrine-disrupting chemicals (EDCs) following early-life exposure; however, the longitudinal epigenetic mechanisms underlying this process remain elusive. Here, the dynamic epigenomic landscape of the mouse uterus was investigated following maternal exposure to bisphenol AF (BPAF), a typical and readily accessible EDC, across three critical developmental stages: postnatal day 10 (PND10), PND21, and PND90. Epigenetic clock analysis revealed that BPAF exposure significantly accelerated epigenetic aging at PND10 and increased the proportion of highly methylated CpG sites at PND90. Analysis of differentially methylated regions (DMRs) demonstrated that the number of DMRs peaked at PND21 and that the majority were located in distal regulatory regions, suggesting that this stage represents a critical window linking early epigenetic perturbations to later-life methylation alterations. DNA pull-down and siRNA-mediated knockdown experiments further demonstrated that BPAF-induced hypermethylation directly impaired the binding of the transcription factor forkhead box L2 (FOXL2), and that FOXL2 is functionally required for dysregulation of the guanine nucleotide-binding protein, alpha stimulating (Gnas)-matrix metalloproteinase 9 (MMP9) axis. This disruption established a pathogenic regulatory axis centered on the differentially methylated gene Gnas, which was subsequently associated with downstream estrogen signaling pathways and the target effector protein MMP9, ultimately leading to the late-onset uterine injuries observed at PND90. In summary, this study demonstrates that maternal BPAF exposure induces epigenetic reprogramming of the mouse uterus and comprehensively delineated the longitudinal evolutionary trajectory of late-onset reproductive toxicity. These findings provide a novel molecular perspective for understanding the cross-developmental pathogenic mechanisms of EDCs.