title: P-glycoprotein traffics from the nucleus to the plasma membrane in rat brain endothelium during inflammatory pain.
abstract: P-glycoprotein (PgP), a drug efflux pump in blood-brain barrier endothelial cells, is a major clinical obstacle for effective central nervous system drug delivery. Identifying PgP regulatory pathways that can be exploited clinically is critical for improving central nervous system drug delivery. We previously found that PgP activity increases in rat brain microvessels concomitant with decreased central nervous system drug delivery in response to acute peripheral inflammatory pain. In the current study, we tested the hypothesis that PgP traffics to the luminal plasma membrane of the microvessel endothelial cells from intracellular stores during peripheral inflammatory pain. Using immunofluorescence microscopy, we detected PgP in endothelial cell nuclei and in the luminal plasma membrane in control animals. Following peripheral inflammatory pain, luminal PgP staining increased while staining in the nucleus decreased. Biochemical analysis of nuclear PgP content confirmed our visual observations. Peripheral inflammatory pain also increased endothelial cell luminal staining of polymerase 1 and transcript release factor/cavin1 and serum deprivation response protein/cavin2, two caveolar scaffold proteins, without changing caveolin1 or protein kinase C delta binding protein/cavin3 location. Our data (a) indicate that PgP traffics from stores in the nucleus to the endothelial cell luminal membrane in response to peripheral inflammatory pain; (b) provide an explanation for our previous observation that peripheral inflammatory pain inhibits central nervous system drug uptake; and (c) suggest a novel regulatory mechanism for PgP activity in rat brain.
authors.affiliation: Department of Pharmacology, University of Arizona, Tucson, USA mtome@email.arizona.edu.
authors.forename: Margaret E
authors.initials: ME
authors.lastname: Tome
authors.affiliation: Department of Pharmacology, University of Arizona, Tucson, USA.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Herndon
authors.affiliation: Department of Pharmacology, University of Arizona, Tucson, USA.
authors.forename: Charles P
authors.initials: CP
authors.lastname: Schaefer
authors.affiliation: Department of Pharmacology, University of Arizona, Tucson, USA.
authors.forename: Leigh M
authors.initials: LM
authors.lastname: Jacobs
authors.affiliation: Department of Pharmacology, University of Arizona, Tucson, USA.
authors.forename: Yifeng
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Pharmacology, University of Arizona, Tucson, USA.
authors.forename: Chelsea K
authors.initials: CK
authors.lastname: Jarvis
authors.affiliation: Department of Pharmacology, University of Arizona, Tucson, USA.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Davis
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D001812:Blood-Brain Barrier / Q000000981:diagnostic imaging / Q000378:metabolism*; D002351:Carrageenan / Q000494:pharmacology; D051242:Caveolin 1 / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D055806:Microvessels / Q000000981:diagnostic imaging / Q000378:metabolism; D020078:Neurogenic Inflammation / Q000000981:diagnostic imaging / Q000378:metabolism*; D021381:Protein Transport; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D051242:Caveolin 1; C105104:Cavin3 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D012965:Sodium Chloride; D002351:Carrageenan
keywords: Caveolin1; P-glycoprotein; polymerase 1 and transcript release factor/cavin1; protein kinase C delta binding protein/cavin3; serum deprivation response protein/cavin2; trafficking