N-acetylcysteine inhibits induction of nitric oxide synthase in 3T3-L1 adipocytes.
The present study was designed to determine whether N-acetylcysteine (NAC), a potent antioxidant, modulates nitric oxide (NO) production stimulated by lipopolysaccharide (LPS) and tumor necrosis factor-alpha (TNF-alpha) in adipocytes. Stimulation by the combination of 5 microg/ml of LPS and 100 ng/ml of TNF-alpha (LT) significantly enhanced NO production in 3T3-L1 adipocytes. Preincubation of the cells with NAC (5-20 mM) for 24 h suppressed the increased NO production in a dose-dependent manner. The production of NO was decreased by 49% at the concentration of 20 mM of NAC. The decrease in NO production by NAC was accompanied by a decrease in inducible nitric oxide synthase (iNOS) protein, detected by immunoblot analysis, and iNOS mRNA, determined by real-time reverse-transcriptase coupled polymerase chain reaction analysis. Nuclear factor-kappa B (NF-kappa B) was significantly activated by LT-treatment, while the pretreatment with 20 mM of NAC prevented the activity by 42%. Pyrrolidine dithiocarbamate (PDTC), a NF-kappaB inhibitor, also inhibited the LT-mediated NO production dose-dependently. One hundred microM of PDTC inhibited the NO production by 46%. We also investigated the effect of NAC and PDTC on the production of interleukein-6 (IL-6), which is regulated transcriptionally by NF-kappa B in 3T3-L1 adipocytes. IL-6 production was markedly increased by LT stimulus, and the enhanced secretion of IL-6 was suppressed in a dose-dependent manner by pretreatment with NAC or PDTC. These results suggest that NAC regulates iNOS expression and NO production in adipocytes through the modulating activation of NF-kappa B.
Araki
Shunsuke
S
Department of Pediatrics, School of Medicine, University of Occupational and Environmental Health, Japan.
Dobashi
Kazushige
K
Kubo
Kazuyasu
K
Kawagoe
Rinko
R
Yamamoto
Yukiyo
Y
Shirahata
Akira
A
D041721:3T3-L1 Cells / Q000201:enzymology* / Q000378:metabolism; D000111:Acetylcysteine / Q000494:pharmacology*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002478:Cells, Cultured; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D004790:Enzyme Induction / Q000187:drug effects; D015850:Interleukin-6 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D018384:Oxidative Stress; D011759:Pyrrolidines / Q000494:pharmacology; D013268:Stimulation, Chemical; D013859:Thiocarbamates / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D000975:Antioxidants; D015850:Interleukin-6; D008070:Lipopolysaccharides; D016328:NF-kappa B; D011759:Pyrrolidines; D013859:Thiocarbamates; D014409:Tumor Necrosis Factor-alpha; C020972:pyrrolidine dithiocarbamic acid; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D000111:Acetylcysteine