Background: Bisphenol A (BPA) is known for endocrine disrupting activity. In order to replace BPA, a number of bisphenol analogues have been designed. However, their activity profile is poorly described and little information exists about their endocrine disrupting potential and interactions with nuclear receptors. An understanding of such interaction may unravel mechanism of their molecular action and provide valuable inputs for risk assessment. BPA binds and activates peroxisome proliferator-activated receptors (PPARs) and retinoid X receptors (RXRs) which act as transcription factors and regulate genes involved in glucose, lipid, and cholesterol metabolism and adipogenesis.
Methods: We studied binding efficiency of 18 bisphenol analogues and BPA with human PPARs and RXRs. Using Maestro Schrodinger 9.4, docking scores of bisphenols were compared with the known endogenous and exogenous ligands of hPPARs and hRXRs.
Results: BPA showed good binding efficiency. Several analogues also showed higher binding efficiency than BPA. BPPH which has high tendency to be absorbed in tissues showed the strongest binding with hPPARα, hPPARβ, hPPARγ, and hRXRα whereas two of the most toxic bisphenols, BPM and BPAF showed strongest binding with hRXRβ and hRXRγ.
Conclusions: Some of the bisphenol analogues showed a stronger binding affinity with PPAR and RXR compared to BPA implying that BPA substitutes may not be fully safe and chemico-biological interactions indicate their toxic potential. These results may also serve to plan further studies for determining safety profile of bisphenol analogues and be helpful in risk characterization.
Keywords: Endocrine disrupting chemicals; bisphenol analogues; nuclear receptors; risk characterization.