Ikappa-B kinase-2 inhibitor blocks inflammation in human airway smooth muscle and a rat model of asthma.

Abstract

Nuclear factor (NF)-kappaB is a transcription factor known to regulate the expression of many inflammatory genes, including cytokines, chemokines, and adhesion molecules. NF-kappaB is held inactive in the cytoplasm, bound to I-kappaB. The removal of I-kappaB, via the actions of inhibitor of kappaB (I-kappaB) kinase-2 (IKK-2), allows NF-kappaB to enter the nucleus. To determine the impact of inhibiting IKK-2 on in vitro and in vivo models of airway inflammation. The effect of inhibiting IKK-2 was assessed in stimulated, cultured, primary human airway smooth muscle cells and an antigen-driven rat model of lung inflammation. The release of cytokines from cultured cells and inflammatory cytokine expression and cellular burden in the lung were determined. Two structurally distinct molecules and dominant negative technology demonstrated that inhibition of IKK-2 activity completely blocked cytokine release from cultured cells, whereas the two glucocorticoid comparators had limited impact on granulocyte colony-stimulating factor, interleukin 8, and eotaxin release. In addition, in an in vivo antigen-driven model of airway inflammation, the IKK-2 inhibitor blocked NF-kappaB nuclear translocation, which was associated with a reduction in inflammatory cytokine gene and protein expression, airway eosinophilia, and late asthmatic reaction, similar in magnitude to that obtained with budesonide. This study demonstrates that inhibiting IKK-2 results in a general reduction of the inflammatory response in vitro and in vivo. Compounds of this class could have therapeutic utility in the treatment of asthma and may, in certain respects, possess a beneficial efficacy profile compared with that of a steroid.