Humans are chronically exposed to multiple exogenous substances, including environmental pollutants, drugs and dietary components. Many of these compounds are suspected to impact human health, and their combination in complex mixtures could exacerbat ...
Humans are chronically exposed to multiple exogenous substances, including environmental pollutants, drugs and dietary components. Many of these compounds are suspected to impact human health, and their combination in complex mixtures could exacerbate their harmful effects. Here we demonstrate that a pharmaceutical oestrogen and a persistent organochlorine pesticide, both exhibiting low efficacy when studied separately, cooperatively bind to the pregnane X receptor, leading to synergistic activation. Biophysical analysis shows that each ligand enhances the binding affinity of the other, so the binary mixture induces a substantial biological response at doses at which each chemical individually is inactive. High-resolution crystal structures reveal the structural basis for the observed cooperativity. Our results suggest that the formation of 'supramolecular ligands' within the ligand-binding pocket of nuclear receptors contributes to the synergistic toxic effect of chemical mixtures, which may have broad implications for the fields of endocrine disruption, toxicology and chemical risk assessment.
Organizational Affiliation:
Inserm U1054, Montpellier 34090, France.,Inserm, U1194, Montpellier 34298, France.,Inserm U661, Montpellier 34094, France.,CNRS UMR5203, Institut de Génomique Fonctionnelle, Montpellier 34094, France.,CHU de Montpellier, Institut de Recherche en Biothérapie, Montpellier 34295, France.,INRA UMR 1331, TOXALIM, Sophia-Antipolis 06903, France.,ICM, Institut régional du Cancer de Montpellier, Montpellier 34298, France.,IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier 34298, France.,NovAliX, Illkirch 67400, France.,CNRS UMR5048, Centre de Biochimie Structurale, Montpellier 34090, France.,Université de Montpellier, Montpellier 34090, France.,Inserm U1040, Montpellier 34295, France.
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