Nitric oxide-dependent N-nitrosating activity of rat pleural mesothelial cells

Recent studies have demonstrated that nitric oxide (NO)-derived N-nitrosating agents may promote mutagenesis and carcinogenesis from the nitrosative deamination of DNA bases via the formation of nitrosamine intermediates. The objective of this study was to determine if pleural mesothelial cells (PMC) stimulated with proinflammatory cytokines could promote the N-nitrosation of a primary aromatic amine via the L-arginine-dependent formation of NO-derived N-nitrosation agents. N-nitrosating activity was determined by measuring the N-nitrosation of a model amine, 2,3-diaminonapthalene, to yield its fluorescent triazole (1-naptho-2,3-triazole) derivative. Results show that specific combinations of TNF, IL-1, interferon gamma, and LPS significantly increased N-nitrosating activity. There was a significant positive correlation between nitrite plus nitrate and triazole production. Triazole formation was inhibited by NG-nitro-L-arginine methyl ester, suggesting that triazole was derived from L-arginine-dependent formation of NO. These data indicate that PMC have the capacity to promote the N-nitrosation of primary aromatic amines via the formation of NO.