Inflammatory activation of airway epithelial cells by pyocyanin

Despite the appreciated in vivo role of the redox-active Pseudomonas virulence factor pyocyanin in Pseudomonas airway infections and the recognized importance of airway epithelial cells in combating bacterial pathogens, little is known about pyocyanin’s effect on airway epithelial cells. We find that exposure of bronchiolar epithelial cells to pyocyanin results in MUC2/MUC5AC induction and mucin secretion mediated by reactive oxygen species production, activation of the epidermal growth factor receptor pathway and release of inflammatory cytokines (IL-1b, IL-6, TGFa, TNFa). Microarray analysis identified 286 pyocyanin-induced genes in airway epithelial cells, including many of the inflammatory mediators elevated in cystic fibrosis airways (G-CSF, GM-CSF, CXCL1, SAA). We also found several novel pyocyanin-responsive genes of potential importance in the infection process (IL-24, CXCL2, CXCL3, CCL20, SOD2). This comprehensive study uncovers numerous details of pyocyanin’s proinflammatory action and establishes airway epithelial cells as key responders following exposure to this microbial toxin. H292 cells were treated with or without 8 uM pyocyanin for 48 hrs in serum-free RPMI medium. RNA was isolated in four independent experiments, collected, processed and subjected to microarray analysis simultaneously (biological repeats).