Widespread environmental chemicals disrupt GRα and PPARγ signaling: Evidence from an integrated experimental and...

Glucocorticoid receptor alpha (GRα) and peroxisome proliferator-activated receptor gamma (PPARγ) are key nuclear receptors that regulate metabolic and endocrine homeostasis. However, the potential of environmental contaminants to interfere with these receptors remains insufficiently characterized. We evaluated the ligand-dependent modulatory effects of 47 environmentally relevant compounds on GRα and PPARγ. Primary screening was conducted using transfected dual-luciferase reporters under non-cytotoxic doses in HEK-293T cells, followed by secondary validation through qPCR analysis of canonical target genes under native GRα and PPARγ expression in Hepa1-6 and AML12 cells, respectively. Among the tested compounds, TPHP, and chlorpyrifos (CP) suppressed GRα-mediated transcription, whereas benzophenone-3 (BP-3), CdCl₂ and dibutyl phthalate (DBP) enhanced GRα-dependent transcription. TBBPA-BHEE, TPHP, DBP, BP-3, and CdCl₂ increased PPARγ-mediated transcription. Molecular docking suggested that key residues, including ASN564 and THR739 in GRα and TYR473 in PPARγ, may be involved in ligand binding and ligand-receptor interactions. Integration with published literature and ToxCast bioactivity profiles further supported the screening findings. Notably, DBP activated GRα signaling, which, to our knowledge, has not been previously reported. This study establishes an integrated screening framework to identify environmental contaminants that modulate GRα and PPARγ signaling, expanding our understanding of receptor-disrupting environmental chemicals.