| Structural highlights
Function
[NR1I2_HUMAN] Nuclear receptor that binds and is activated by variety of endogenous and xenobiotic compounds. Transcription factor that activates the transcription of multiple genes involved in the metabolism and secretion of potentially harmful xenobiotics, drugs and endogenous compounds. Activated by the antibiotic rifampicin and various plant metabolites, such as hyperforin, guggulipid, colupulone, and isoflavones. Response to specific ligands is species-specific. Activated by naturally occurring steroids, such as pregnenolone and progesterone. Binds to a response element in the promoters of the CYP3A4 and ABCB1/MDR1 genes.[1] [2] [3] [4] [5] [6]
Publication Abstract from PubMed
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.
Synergistic activation of human pregnane X receptor by binary cocktails of pharmaceutical and environmental compounds.,Delfosse V, Dendele B, Huet T, Grimaldi M, Boulahtouf A, Gerbal-Chaloin S, Beucher B, Roecklin D, Muller C, Rahmani R, Cavailles V, Daujat-Chavanieu M, Vivat V, Pascussi JM, Balaguer P, Bourguet W Nat Commun. 2015 Sep 3;6:8089. doi: 10.1038/ncomms9089. PMID:26333997[7]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Lehmann JM, McKee DD, Watson MA, Willson TM, Moore JT, Kliewer SA. The human orphan nuclear receptor PXR is activated by compounds that regulate CYP3A4 gene expression and cause drug interactions. J Clin Invest. 1998 Sep 1;102(5):1016-23. PMID:9727070 doi:10.1172/JCI3703
- ↑ Zhang J, Kuehl P, Green ED, Touchman JW, Watkins PB, Daly A, Hall SD, Maurel P, Relling M, Brimer C, Yasuda K, Wrighton SA, Hancock M, Kim RB, Strom S, Thummel K, Russell CG, Hudson JR Jr, Schuetz EG, Boguski MS. The human pregnane X receptor: genomic structure and identification and functional characterization of natural allelic variants. Pharmacogenetics. 2001 Oct;11(7):555-72. PMID:11668216
- ↑ Geick A, Eichelbaum M, Burk O. Nuclear receptor response elements mediate induction of intestinal MDR1 by rifampin. J Biol Chem. 2001 May 4;276(18):14581-7. Epub 2001 Jan 31. PMID:11297522 doi:10.1074/jbc.M010173200
- ↑ Li Y, Ross-Viola JS, Shay NF, Moore DD, Ricketts ML. Human CYP3A4 and murine Cyp3A11 are regulated by equol and genistein via the pregnane X receptor in a species-specific manner. J Nutr. 2009 May;139(5):898-904. doi: 10.3945/jn.108.103572. Epub 2009 Mar 18. PMID:19297428 doi:10.3945/jn.108.103572
- ↑ Watkins RE, Maglich JM, Moore LB, Wisely GB, Noble SM, Davis-Searles PR, Lambert MH, Kliewer SA, Redinbo MR. 2.1 A crystal structure of human PXR in complex with the St. John's wort compound hyperforin. Biochemistry. 2003 Feb 18;42(6):1430-8. PMID:12578355 doi:10.1021/bi0268753
- ↑ Teotico DG, Bischof JJ, Peng L, Kliewer SA, Redinbo MR. Structural basis of human pregnane X receptor activation by the hops constituent colupulone. Mol Pharmacol. 2008 Dec;74(6):1512-20. doi: 10.1124/mol.108.050732. Epub 2008 Sep, 2. PMID:18768384 doi:10.1124/mol.108.050732
- ↑ Delfosse V, Dendele B, Huet T, Grimaldi M, Boulahtouf A, Gerbal-Chaloin S, Beucher B, Roecklin D, Muller C, Rahmani R, Cavailles V, Daujat-Chavanieu M, Vivat V, Pascussi JM, Balaguer P, Bourguet W. Synergistic activation of human pregnane X receptor by binary cocktails of pharmaceutical and environmental compounds. Nat Commun. 2015 Sep 3;6:8089. doi: 10.1038/ncomms9089. PMID:26333997 doi:http://dx.doi.org/10.1038/ncomms9089
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