title: Nitric oxide down-regulates the expression of the catalytic NADPH oxidase subunit Nox1 in rat renal mesangial cells.
abstract: Glomerular mesangial cells can produce high amounts of nitric oxide (NO) and reactive oxygen species (ROS). Here we analyzed the impact of NO on the ROS-generating system, particularly on the NADPH oxidase Nox1. Nox1 mRNA and protein levels were markedly decreased by treatment of mesangial cells with the NO-releasing compound DETA-NO in a concentration- and time-dependent fashion. By altering the cGMP signaling system with different inhibitors or activators, we revealed that the effect of NO on Nox1 expression is at least in part mediated by cGMP. Analysis of a reporter construct comprising the 2547 bp of the nox1 promoter region revealed that a stimulatory effect of IL-1beta on nox1 transcription is counteracted by an inhibitory effect of IL-1beta-evoked endogenous NO formation. Moreover, pretreatment of mesangial cells with DETA-NO attenuated platelet-derived growth factor (PDGF)-BB or serum stimulated production of superoxide as assessed by real-time EPR spectroscopy and dichlorofluorescein formation. Transfection of mesangial cells with siRNAs directed against Nox1 and Nox4 revealed that inhibition of Nox1, but not Nox4 expression, is responsible for the reduced ROS formation by NO. Obviously, there exists a fine-tuned crosstalk between NO and ROS generating systems in the course of inflammatory diseases.
authors.affiliation: Pharmazentrum Frankfurt (ZAFES), Klinikum der Johann Wolfgang-Goethe-Universität, Frankfurt am Main, Germany.
authors.forename: Miriam
authors.initials: M
authors.lastname: Plesková
authors.forename: Karl-Friedrich
authors.initials: KF
authors.lastname: Beck
authors.forename: Meik Helmut
authors.initials: MH
authors.lastname: Behrens
authors.forename: Andrea
authors.initials: A
authors.lastname: Huwiler
authors.forename: Birgit
authors.initials: B
authors.lastname: Fichtlscherer
authors.forename: Oliver
authors.initials: O
authors.lastname: Wingerter
authors.forename: Ralf P
authors.initials: RP
authors.lastname: Brandes
authors.forename: Alexander
authors.initials: A
authors.lastname: Mülsch
authors.forename: Josef
authors.initials: J
authors.lastname: Pfeilschifter
mesh_terms: D000818:Animals; D020134:Catalytic Domain; D002478:Cells, Cultured; D003001:Cloning, Molecular; D015536:Down-Regulation; D015971:Gene Expression Regulation, Enzymologic; D007375:Interleukin-1 / Q000494:pharmacology; D050527:Mesangial Cells / Q000187:drug effects / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D000074624:NADPH Oxidase 1; D009569:Nitric Oxide / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D034741:RNA, Small Interfering; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D024363:Transcription Initiation Site; D014226:Triazenes / Q000494:pharmacology
chemical_list: C105351:1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)-1-triazene; D007375:Interleukin-1; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D014226:Triazenes; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D009247:NADH, NADPH Oxidoreductases; D000074624:NADPH Oxidase 1; C000614712:NOX1 protein, rat