title: P-glycoprotein and breast cancer resistance protein expression and function at the blood-brain barrier and blood-cerebrospinal fluid barrier (choroid plexus) in streptozotocin-induced diabetes in rats.
abstract: The aim of the study was to investigate the influence of diabetes mellitus type 1 on expression and function of the ATP-binding cassette transport proteins P-glycoprotein (Pgp, Abcb1) and breast cancer resistance protein (Bcrp, Abcg2) at the blood-brain barrier and the blood-cerebrospinal fluid barrier formed by the choroid plexus. In brain capillary endothelial cells forming the blood-brain barrier, Pgp and Bcrp are located in the luminal membrane while apical/sub-apical localization was described for Pgp in choroid plexus epithelial cells. Alterations in expression or function may lead to damages in barrier integrity and may cause brain defects after long term diabetes. Diabetes was induced by i.p.-streptozotocin injection 14days prior to performing experiments. RNA and protein expression were analyzed in choroid plexus and blood-brain barrier capillaries by RT-PCR and Western blot, respectively. Pgp and Bcrp expression was increased in blood-brain barrier capillaries; in choroid plexus, only Bcrp showed elevated gene expression. Protein expression was not altered. Functional analyses were carried out using confocal laser-scanning microscopy in intact isolated brain capillaries with the fluorescent Pgp substrate NBD-Cyclosporin A (NBD-CsA) and BODIPY® FL prazosin as substrate for Bcrp. Consistent with protein expression data, no changes in diabetic animals occurred, suggesting an unaltered function of Pgp and Bcrp.
authors.affiliation: Department Pharmaceutical Technology and Biopharmacy, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany. reichel@uni-hd.de
authors.forename: Valeska
authors.initials: V
authors.lastname: Reichel
authors.forename: Simone
authors.initials: S
authors.lastname: Burghard
authors.forename: Isabel
authors.initials: I
authors.lastname: John
authors.forename: Olga
authors.initials: O
authors.lastname: Huber
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis / Q000235:genetics*; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis / Q000235:genetics*; D000818:Animals; D001812:Blood-Brain Barrier / Q000378:metabolism* / Q000503:physiopathology; D002831:Choroid Plexus / Q000378:metabolism* / Q000503:physiopathology; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015854:Up-Regulation / Q000235:genetics
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; C489249:Abcg2 protein, rat; D012333:RNA, Messenger