Lipopolysaccharide-activated microglia lower P-glycoprotein function in brain microvascular endothelial cells.
P-glycoprotein, an efflux transporter that is highly expressed at the blood-brain barrier (BBB), is involved in the traffic of several compounds across the BBB. BBB disruption under pathological conditions is observed in parallel with microglial activation. Previous studies of the interaction between rat brain endothelial cells (RBECs) and microglia have shown that lipopolysaccharide (LPS) activated microglia increase the permeability of RBECs through a mechanism involving NADPH oxidase. In this study, to investigate whether LPS-activated microglia are linked to P-gp dysfunction at the BBB, we examined the effect of LPS on P-gp function in a coculture system with RBECs and rat microglia. When LPS at a concentration showing no effect on the RBEC monolayer was added for 6h to the abluminal side of the RBEC monolayer and RBEC/microglia cocultures, cellular accumulation of the P-gp substrate rhodamine 123, in RBECs, was increased by LPS in the RBEC/microglia coculture. This increased accumulation of rhodamine 123 in RBECs was blocked by diphenyleneiodoniumchloride, an NADPH oxidase inhibitor. P-gp expression on RBECs was not influenced by treatment with LPS in either RBEC monolayers or RBEC/microglia cocultures. These findings suggest that activated microglia induce P-gp dysfunction at the BBB through an NADPH oxidase-dependent pathway.
Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan.
Junichi
J
Matsumoto
Shinya
S
Dohgu
Fuyuko
F
Takata
Tsuyoshi
T
Nishioku
Noriko
N
Sumi
Takashi
T
Machida
Hiroyuki
H
Takahashi
Atsushi
A
Yamauchi
Yasufumi
Y
Kataoka
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001812:Blood-Brain Barrier / Q000378:metabolism; D001921:Brain / Q000098:blood supply*; D002478:Cells, Cultured; D018920:Coculture Techniques; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D005456:Fluorescent Dyes; D008070:Lipopolysaccharides / Q000494:pharmacology*; D017628:Microglia / Q000187:drug effects / Q000378:metabolism*; D055806:Microvessels / Q000187:drug effects / Q000378:metabolism*; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009861:Onium Compounds / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D020112:Rhodamine 123
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D005456:Fluorescent Dyes; D008070:Lipopolysaccharides; D009861:Onium Compounds; D020112:Rhodamine 123; C007517:diphenyleneiodonium; D019255:NADPH Oxidases