title: N-acetyl-L-cysteine enhances interleukin-1beta-induced nitric oxide synthase expression.
abstract: The effect of N-acetyl-L-cysteine on interleukin-1beta-induced nitric oxide synthase expression was studied in rat vascular smooth muscle cells to determine if the reduction/oxidation state would modulate cytokine-induced changes. Interleukin-1beta induced the production of nitrite, a stable metabolite of nitric oxide in a time- and dose-dependent manner. Cytokine-induced nitrite production was enhanced by the addition of N-acetyl-L-cysteine in a dose-dependent manner, with a >50% increase produced by the addition of 1 mmol/L N-acetyl-L-cysteine. There was no influence on nitrite production when the cells were treated with N-acetyl-L-cysteine alone. Northern and Western blot analyses revealed that the upregulation of interleukin-1beta-induced nitric oxide production by N-acetyl-L-cysteine resulted from an enhanced expression of inducible nitric oxide synthase. Interferon-gamma or tumor necrosis factor-alpha when used alone had no influence on nitrite production in the absence or presence of N-acetyl-L-cysteine. Nitrite accumulation was higher by the cells treated with interleukin-1beta combined with either interferon-gamma or tumor necrosis factor-alpha compared with those treated with interleukin-1beta alone. N-Acetyl-L-cysteine upregulated nitrite production and inducible nitric oxide synthase expression induced by combination treatment with interleukin-1beta and either interferon-gamma or tumor necrosis factor-alpha. However, N-acetyl-L-cysteine had no significant influence in cytokine-induced activation of nuclear factor-kappaB or signal transducer and activator of transciption-1, as assessed by electrophoretic mobility shift assays. These results demonstrate that N-acetyl-L-cysteine possibly acted as a thiol-containing reducing agent and facilitated the expression of inducible nitric oxide synthase in rat vascular smooth muscle cells by cytokines through a mechanism that is independent of nuclear factor-kappaB or signal transducer and activator of transciption-1.
authors.affiliation: Department of Biochemistry, Whitaker Cardiovascular Institute, Boston University School of Medicine, Mass 02118, USA.
authors.forename: B
authors.initials: B
authors.lastname: Jiang
authors.forename: M
authors.initials: M
authors.lastname: Haverty
authors.forename: P
authors.initials: P
authors.lastname: Brecher
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D004357:Drug Synergism; D004586:Electrophoresis; D007375:Interleukin-1 / Q000494:pharmacology*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000096:biosynthesis* / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D007375:Interleukin-1; D009573:Nitrites; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D000111:Acetylcysteine