Unraveling ER dimerization dynamics in endocrine disruption based on a BRET-focused approach.

Endocrine-disrupting chemicals (EDCs) are exogenous compounds that interact with the estrogen receptor (ER), thereby disrupting estrogen-mediated signaling. In a previous study, we employed a bioluminescence resonance energy transfer (BRET) system to assess ER dimerization for detecting EDCs. To further determine whether the BRET assay could be used independently to identify EDCs, we investigated ER-EDC interactions before and after dimerization. Results from isothermal titration calorimetry (ITC) and dynamic light scattering (DLS) revealed that ER dimerization can be mediated by EDCs. Consequently, the BRET assay proved effective in detecting dimerization and clarifying its relevance to EDC-induced signaling disruption. Additionally, to examine EDC-induced transcriptional changes, we performed chromatin immunoprecipitation sequencing (ChIP-seq), followed by gene ontology (GO) analysis. These analyses demonstrated that EDCs affect various signaling pathways, including those involved in antibody-dependent cytotoxicity, bone morphogenetic protein (BMP) signaling in cardiac induction, and hepatocyte growth factor receptor signaling. Overall, this study elucidates the molecular mechanisms by which EDCs influence ER dimerization and signaling. These findings highlight the utility of the BRET-based assay for EDC detection and contribute to a deeper understanding of the systemic effects of EDCs on endocrine disruption.