Activation of PKC isoform beta(I) at the blood-brain barrier rapidly decreases P-glycoprotein activity and enhances drug delivery to the brain.

Published

Journal Article

P-glycoprotein is an ATP (adenosine triphosphate)-driven drug efflux transporter that is highly expressed at the blood-brain barrier (BBB) and is a major obstacle to the pharmacotherapy of central nervous system diseases, including brain tumors, neuro-AIDS, and epilepsy. Previous studies have shown that P-glycoprotein transport activity in rat brain capillaries is rapidly reduced by the proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha) acting through protein kinase C (PKC)-dependent signaling. In this study, we used isolated rat brain capillaries to show that the TNF-alpha-induced reduction of P-glycoprotein activity was prevented by a PKCbeta(I/II) inhibitor, LY333531, and mimicked by a PKCbeta(I/II) activator, 12-deoxyphorbol-13-phenylacetate-20-acetate (dPPA). Western blotting of brain capillary extracts with phospho-specific antibodies showed that dPPA activated PKCbeta(I), but not PKCbeta(II). Moreover, in intact rats, intracarotid infusion of dPPA potently increased brain accumulation of the P-glycoprotein substrate, [(3)H]-verapamil without compromising tight junction integrity. Thus, PKCbeta(I) activation selectively reduced P-glycoprotein activity both in vitro and in vivo. Targeting PKCbeta(I) at the BBB may prove to be an effective strategy for enhancing the delivery of small molecule therapeutics to the brain.

Full Text

Duke Authors

Cited Authors

  • Rigor, RR; Hawkins, BT; Miller, DS

Published Date

  • July 2010

Published In

Volume / Issue

  • 30 / 7

Start / End Page

  • 1373 - 1383

PubMed ID

  • 20197783

Pubmed Central ID

  • 20197783

Electronic International Standard Serial Number (EISSN)

  • 1559-7016

International Standard Serial Number (ISSN)

  • 0271-678X

Digital Object Identifier (DOI)

  • 10.1038/jcbfm.2010.21

Language

  • eng