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J Cereb Blood Flow Metab. 2017 Apr;37(4):1199-1212. doi: 10.1177/0271678X16650216. Epub 2016 Jan 1.

PPAR-α, a lipid-sensing transcription factor, regulates blood-brain barrier efflux transporter expression.

Author information

1
Signal Transduction Laboratory, National Institute of Environmental Health Sciences (NIEHS), National Institute of Health, Research Triangle Park, NC, USA.

Abstract

Lipid sensor peroxisome proliferator-activated receptor alpha (PPAR- α) is the master regulator of lipid metabolism. Dietary release of endogenous free fatty acids, fibrates, and certain persistent environmental pollutants, e.g. perfluoroalkyl fire-fighting foam components, are peroxisome proliferator-activated receptor alpha ligands. Here, we define a role for peroxisome proliferator-activated receptor alpha in regulating the expression of three ATP-driven drug efflux transporters at the rat and mouse blood-brain barriers: P-glycoprotein (Abcb1), breast cancer resistance protein (Bcrp/Abcg2), and multidrug resistance-associated protein 2 (Mrp2/Abcc2). Exposing isolated rat brain capillaries to linoleic acid, clofibrate, or PKAs increased the transport activity and protein expression of the three ABC transporters. These effects were blocked by the PPAR- α antagonist, GW6471. Dosing rats with 20 mg/kg or 200 mg/kg of clofibrate decreased the brain accumulation of the P-glycoprotein substrate, verapamil, by 50% (in situ brain perfusion; effects blocked by GW6471) and increased P-glycoprotein expression and activity in capillaries ex vivo. Fasting C57Bl/6 wild-type mice for 24 h increased both serum lipids and brain capillary P-glycoprotein transport activity. Fasting did not alter P-glycoprotein activity in PPAR- α knockout mice. These results indicate that hyperlipidemia, lipid-lowering fibrates and exposure to certain fire-fighting foam components activate blood-brain barrier peroxisome proliferator-activated receptor alpha, increase drug efflux transporter expression and reduce drug delivery to the brain.

KEYWORDS:

Blood–brain barrier; P-glycoprotein; PPAR; fasting; fibrate

PMID:
27193034
PMCID:
PMC5453444
DOI:
10.1177/0271678X16650216
[Indexed for MEDLINE]
Free PMC Article

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