title: Catalase potentiates interleukin-1beta-induced expression of nitric oxide synthase in rat vascular smooth muscle cells.
abstract: The role of reactive oxygen species (ROS) in regulating the expression of the inducible nitric oxide synthase (iNOS) was studied in rat aortic vascular smooth muscle cells (VSMC). We hypothesized that ROS regulate iNOS expression through the mitogen-activated protein kinases ERK and p38(MAPK). We found that interleukin-1beta (IL-1beta) stimulated the production of hydrogen peroxide (H2O2) which could be inhibited by loading the cells with the H2O2-scavenging enzyme catalase. Inhibition of the upstream ERK1,2 activator MEK1,2 with U0126 prevented IL-1beta-stimulated iNOS expression, while the p38MAPK inhibitor SB03580 potentiated iNOS expression. Loading the cells with catalase enhanced ERK activation and iNOS expression but had no effect on p38MAPK activation or PDGF-induced ERK activation. These data indicated that H2O2 negatively regulates iNOS expression through ERK inhibition independently of p38MAPK. The present results outline a novel role for H2O2 in suppressing signaling pathways leading to gene expression such as iNOS in VSMC in response to cytokines.
authors.affiliation: Center for Cardiovascular Sciences, Albany Medical College, 47 New Scotland Avenue (MC8), Albany, NY 12208, USA.
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Guikema
authors.forename: Roman
authors.initials: R
authors.lastname: Ginnan
authors.forename: Harold A
authors.initials: HA
authors.lastname: Singer
authors.forename: David
authors.initials: D
authors.lastname: Jourd'heuil
mesh_terms: D000818:Animals; D002374:Catalase / Q000502:physiology*; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006861:Hydrogen Peroxide / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D007375:Interleukin-1 / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors
chemical_list: D007093:Imidazoles; D007375:Interleukin-1; D016328:NF-kappa B; D011725:Pyridines; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D002374:Catalase; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580