Anti-HBE1 (aa 55-83) polyclonal antibody

Mucin over-production is one of the hallmarks of chronic airway diseases such as chronic obstructive pulmonary disease, asthma, and cystic fibrosis. NF-kappa B activation in airway epithelial cells has been shown to play a positive inflammatory role in chronic airway diseases; however, the role of NF-kappa B in mucin gene expression is unresolved. In this study, we have shown that the proinflammatory cytokines, IL-1 beta and IL-17A, both of which utilize the NF-kappa B pathway, are potent inducers of mucin (MUC)5AC mRNA and protein synthesis by both well-differentiated primary normal human bronchial epithelial cells and the human bronchial epithelial cell line, HBE1. MUC5AC induction by these cytokines was both time- and dose-dependent and occurred at the level of promoter activation, as measured by a reporter gene assay. These effects were attenuated by the small molecule inhibitor NF-kappa B inhibitor 111, as well as p65 small-interfering RNA, suggesting that the regulation of MUC5AC expression by these cytokines is via an NF-kappa B-based transcriptional mechanism. Further investigation of the promoter region identified a putative NF-kappa B binding site at position-3594/-3582 in the promoter of MUC5AC as critical for the regulation of MUC5AC expression by both IL-1 beta and IL-17A.. Chromatin immunoprecipitation analysis confirmed enhanced binding of the NF-kappa B subunit p50 to this region following cytokine stimulation. We conclude that an NF-kappa B-based transcriptional mechanism is involved in MUC5AC regulation by IL-1 beta and IL-17A in the airway epithelium. This is the first demonstration of the participation of NF-kappa B and its specific binding site in cytokine-mediated airway MUC5AC expression. The Journal of Immunology, 2009, 183: 6236-6243.

Neutrophil-dependent reactions catalysed by myeloperoxidase (MPO) are thought to play important roles in the pulmonary pathobiology of cystic fibrosis (CF). Aerosolized thiol antioxidants such as glutathione (GSH) and N-acetylcysteine (NAC) are currently being utilized as therapeutics to modify CF respiratory tract oxidative processes. This study hypothesized that MPO in CF airway lining fluids may be a target of such therapeutics. MPO activity in sputum from 21 adult CF patients was found to be inversely associated with lung function (FEV1). In contrast, systemic inflammation (assessed by plasma C-reactive protein) was not correlated with lung function. Ex vivo studies revealed that GSH and NAC effectively scavenged N-chloramines in sputum and inhibited sputum MPO activity with potency exquisitely dependent upon MPO activity levels. Detailed kinetic analyses revealed that NAC and GSH inhibit MPO by distinct mechanisms. Activation of the key pro-inflammatory transcription factor NF-kappa B in cultured HBE1 cells was inhibited by GSH. The findings reveal that MPO activity and its reactive products represent useful predictors of the doses of inhaled thiol antioxidants required to ameliorate airway oxidative stress and inflammation in CF patients and provide mechanistic insight into the antioxidative/anti-inflammatory mechanisms of action of GSH and NAC when administered into the CF lung.