title: Vasopressin type 1A receptor up-regulation by cyclosporin A in vascular smooth muscle cells is mediated by superoxide.
abstract: Based on our previous results, we investigated whether cyclosporin A (CsA)-induced vasopressin type 1A receptor up-regulation was mediated by free radicals. We report that CsA analogues with different affinities for cyclophilin and calcineurin were able to up-regulate vasopressin type 1A receptor and to generate free radicals in smooth muscle cells independently of calcineurin. Further, we demonstrate that the antioxidant N-acetyl-L-cysteine blocked the increase in vasopressin type 1A receptor mRNA and protein levels induced by CsA and that low concentrations of prooxidants were able to directly increase vasopressin type 1A receptor mRNA and protein levels. In addition, short exposure to CsA or pro-oxidants was sufficient to significantly increase vasopressin type 1A receptor mRNA and protein levels. Using cell-permeable forms of superoxide dismutase and catalase, we finally show that superoxide mediates the CsA-induced effects on vasopressin type 1A receptor. These results provide strong evidence that CsA-induced superoxide generation is causally involved in vasopressin type 1A receptor expression and demonstrate for the first time that low physiological concentrations of radicals, most probably superoxide, are able to directly affect cellular signaling to increase vasopressin type 1A receptor expression in rat aortic smooth muscle cells.
authors.affiliation: Pharmacology Group, School of Pharmacy, University of Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Krauskopf
authors.forename: Philippe
authors.initials: P
authors.lastname: Lhote
authors.forename: Manfred
authors.initials: M
authors.lastname: Mutter
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Dufour
authors.forename: Urs T
authors.initials: UT
authors.lastname: Ruegg
authors.forename: Timo M
authors.initials: TM
authors.lastname: Buetler
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology; D019703:Calcineurin / Q000494:pharmacology; D002374:Catalase / Q000378:metabolism; D021983:Cyclophilins / Q000494:pharmacology; D016572:Cyclosporine / Q000494:pharmacology*; D005609:Free Radicals / Q000378:metabolism; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D017483:Receptors, Vasopressin / Q000096:biosynthesis*; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D005609:Free Radicals; D012333:RNA, Messenger; D017483:Receptors, Vasopressin; D013481:Superoxides; D016572:Cyclosporine; D002374:Catalase; D013482:Superoxide Dismutase; D019703:Calcineurin; D021983:Cyclophilins