Expression and activation of the major subunit of NF-kB, protein p65, in COPD bronchial glands

Activation of NF-kB is involved in the regulation of many inducible genes that en- code for inflammatory proteins potentially relevant to the pathogenesis of chronic obstructive pulmonary disease (COPD) and we have previously demonstrated NF- kB activation in sputum macrophages during COPD exacerbations. In vitro, p65 (the major NF-kB subunit) also has a role in MUC5AC secretion from bronchial epithelial cells. The aim of our study was to investigate by immunohistochemistry the localization and activation of p65 in the bronchial rings, obtained during lung resection surgery, of smokers (current and ex) with or without COPD com- pared with non-smoker subjects. We examined formalin-fixed paraffin-embedded bronchial rings by immunohistochemistry for identification of p65+ cells. The number of p65 +ve cells was determined among the mucous cells in the bronchial submucosal glands. Nuclear staining for p65, an index of its activation, was also counted. Samples from 9 age-matched non-smokers subjects, 29 smokers with normal lung function and 29 smokers with COPD were obtained. We were unable to detect any significant differences in p65 expression and nuclear localization in the bronchial mucous glands between the 3 group of subjects. This data suggests that the NF-kB pathway is not critical for MUC5AC secretion in the bronchial glands of COPD patients.