Abstract:Objective and Design: Cytokine expression is controlled by transcription factors including NFB, which has recently been found to exist in human neutrophils. We previously showed that exogenous nitric oxide (NO) induces neutrophil apoptosis and hypothesized that this NO effect could be mediated by inhibition of NFB activation.Materials and methods: Isolated human neutrophils were incubated with or without S-nitrosoglutathione (GSNO 0.1mM-5mM; Sigma) for 2 h. Neutrophils were either unstimulated or stimulated with TNF or n-formyl methionyl leucine phenylalanine (fMLP). Viability was assessed by vital dye cytotoxicity assay. After nuclear extraction and measurement of protein concentration, NFB binding was determined by electrophoretic mobility shift assay. Effects of GSNO on activation of IB, which inhibits intranuclear translocation of NFB, were measured by Western immunoblot technique. For comparison, experiments were also performed in the presence of the NFB inhibitor PDTC.Results: TNF increased nuclear NFB activity compared to unstimulated neutrophils (p0.001, n=5). GSNO (500 M) decreased TNF-induced NFB activity (p0.05) and inhibited NFB activity whether given prior to or during TNF exposure. IB was significantly degraded at 30 and 120 min of TNF exposure compared to control neutrophils (p0.05). GSNO exposure (500 M) inhibited IB degradation in the presence of TNF. PDTC enhanced neutrophil cell death and DNA fragmentation, in association with decreased NFB activity, similar to GSNO effects.Conclusion: Neutrophils possess NFB activity that is increased by stimulation with TNF. GSNO inhibits NFB activity in association with inhibiting TNF-induced degradation of IB. GSNO effects are similar to those seen with NFB inhibition by PDTC. Inhibition of NFB could represent a potential anti-inflammatory effect of GSNO.