Molecular Mechanism Of Bisphenol A On Androgen Receptor Antagonism

Bisphenol A?BPA?is one of the highest production volume chemicals,with an annual global production of more than 3.6 million tons.BPA is widely used in manufacturing polycarbonate plastics and epoxy resins due to remarkable properties of BPA-based products such as durable and tough.Due to its widespread use in industry and daily life,BPA can be released from products and migrate in environment.It is almost ubiquitous in the environment and has been detected in water,soil,air,food,and human tissues.BPA is a typical endocrine-disrupting chemicals?EDCs?.It has anti-androgenic effects and affects the growth and reproduction of male.The previous studies have shown that BPA interfered with the normal function of AR by the AR-mediated pathway,but molecular mechanism of its action is still unclear.In this study,we attempted to explore the molecular mechanism of BPA on AR antagonism.This study will provide scientific basis for the toxicological mechanism of BPA and health risk assessment of BPA,and provide an important reference for the molecular mechanism of EDCs selective interference with different steroid hormone receptors.In this study,the in vitro assays such as reporter gene assay,western blotting,co-immunoprecipitation and immunofluorescence experiments were carried out to determine the effects of BPA on AR transcriptional activity,degradation and stabilization of AR protein,dissociation of chaperone?90-k Da heat shock protein,Hsp90?with AR,and AR nuclear translocation.The in silico study such as molecular docking and molecular dynamics simulations were conducted to simulate the binding mode of BPA with AR.The MTS assay results indicated that BPA at concentrations of 10^-10-10^-4 M had no effects on CHO-K1 cell viability.In reporter gene assay,BPA caused a significant antagonistic effect on 5?-dihydrotestosterone?DHT?-induced AR transcriptional activity at concentrations of 10^-9-10^-5 M.The results of molecular docking and molecular dynamics simulations indicated the availability of BPA binding to the ligand binding domain?LBD?of AR and the bond of BPA made structure of LBD more stable.In addition,we found that BPA at concentrations of 10^-7-10^-5 M prevented the inhibition of receptor degradation caused by DHT binding to AR,and this effect was most pronounced at a BPA concentration of 10^-5 M,reducing the AR expression to 52%of the positive control.BPA exposure also abolished DHT-dependent dissociation of AR from its co-chaperone Hsp90 and resulted in the blockage of DHT-induced AR nuclear translocation.In conclusion,this study showed that BPA as an antiandrogen affected multiple steps of AR activation and function,which provided new data for further understanding the molecular mechanism of BPA on AR antagonism.