Mechanisms of persistent NF-κB activity in the bronchi of an animal model of asthma

F. Bureau*, S. Delhalle, G. Bonizzi, L. Fievez, S. Dogne, N. Kirschvink, A. Vanderplasschen, M. P. Merville, V. Bours, P. Lekeux

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

123 Citations (Scopus)


In most cells trans-activating NF-κB induces many inflammatory proteins as well as its own inhibitor, IκB-α, thus assuring a transient response upon stimulation. However, NF-κB-dependent inflammatory gene expression is persistent in asthmatic bronchi, even after allergen eviction. In the present report we used bronchial brushing samples (BBSs) from heaves-affected horses (a spontaneous model of asthma) to elucidate the mechanisms by which NF-κB activity is maintained in asthmatic airways. NF-κB activity was high in granulocytic and nongranulocytic BBS cells. However, NF-κB activity highly correlated to granulocyte percentage and was only abrogated after granulocytic death in cultured BBSs. Before granulocytic death, NF-κB activity was suppressed by simultaneous addition of neutralizing anti-IL-1β and anti-TNF-α Abs to the medium of cultured BBSs. Surprisingly, IκB-β, whose expression is not regulated by NF-κB, unlike IκB-α, was the most prominent NF-κB inhibitor found in BBSs. The amounts of IκB-β were low in BBSs obtained from diseased horses, but drastically increased after addition of the neutralizing anti-IL-1β and anti-TNF-α Abs. These results indicate that sustained NF-κB activation in asthmatic bronchi is driven by granulocytes and is mediated by IL-1β and TNF-α. Moreover, an imbalance between high levels of IL-1β- and TNF-α-mediated IκB-β degradation and low levels of IκB-β synthesis is likely to be the mechanism preventing NF-κB deactivation in asthmatic airways before granulocytic death.

Original languageEnglish
Pages (from-to)5822-5830
Number of pages9
JournalJournal of Immunology
Issue number10
Publication statusPublished - 15 Nov 2000
Externally publishedYes


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