Aryl hydrocarbon receptor-mediated up-regulation of ATP-driven xenobiotic efflux transporters at the blood-brain barrier.

Published

Journal Article

Many widespread and persistent organic pollutants, e.g., 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), activate the aryl hydrocarbon receptor (AhR), causing it to translocate to the cell nucleus, where it transactivates target genes. AhR's ability to target the blood-brain barrier is essentially unexplored. We show here that exposing isolated rat brain capillaries to 0.05-0.5 nM TCDD roughly doubled transport activity and protein expression of P-glycoprotein, an ATP-driven drug efflux pump and a critical determinant of drug entry into the CNS. These effects were abolished by actinomycin D or cycloheximide or by the AhR antagonists resveratrol and α-naphthoflavone. Brain capillaries from TCDD-dosed rats (1-5 μg/kg, i.p.) exhibited increased transport activity and protein expression of 3 xenobiotic efflux pumps, P-glycoprotein, multidrug resistance-associated protein 2, and breast cancer resistance polypeptide, as well as expression of Cyp1a1 and Cyp1b1, both AhR target genes. Consistent with increased P-glycoprotein expression in capillaries from TCDD-dosed rats, in situ brain perfusion indicated significantly reduced brain accumulation of verapamil, a P-glycoprotein substrate. These findings suggest a new paradigm for the field of environmental toxicology: toxicants acting through AhR to target xenobiotic efflux transporters at the blood-brain barrier and thus reduce brain accumulation of CNS-acting therapeutic drugs.

Full Text

Duke Authors

Cited Authors

  • Wang, X; Hawkins, BT; Miller, DS

Published Date

  • February 2011

Published In

Volume / Issue

  • 25 / 2

Start / End Page

  • 644 - 652

PubMed ID

  • 21048045

Pubmed Central ID

  • 21048045

Electronic International Standard Serial Number (EISSN)

  • 1530-6860

International Standard Serial Number (ISSN)

  • 0892-6638

Digital Object Identifier (DOI)

  • 10.1096/fj.10-169227

Language

  • eng