The discovery of novel antiinflammatory targets to treat
inflammation in the
cystic fibrosis (CF) lung stands to benefit patient populations suffering with this disease. The Pseudomonas aeruginosa quorum sensing autoinducer N-3-oxododecanoyl
homoserine lactone (3O-C12) is an important bacterial
virulence factor that has been reported to induce proinflammatory
cytokine production from a variety of cell types. The goal of this study was to examine the ability of 3O-C12 to induce proinflammatory
cytokine production in normal and CF bronchial epithelial cells, and better understand the cellular mechanisms by which this
cytokine induction occurs. 3O-C12 was found to induce higher levels of
IL-6 production in the CF cell lines IB3-1 and CuFi, compared to their corresponding control cell lines C38 and NuLi. Systems biology and network analysis revealed a high predominance of over-represented innate immune pathways bridged together by
calcium-dependant
transcription factors governing the transcriptional responses of A549 airway cells to stimulation with 3O-C12. Using
calcium-flux assays, 3O-C12 was found to induce larger and more sustained increases in intracellular
calcium in IB3-1 cells compared to C38, and blocking this
calcium flux with
BAPTA-AM reduced the production of
IL-6 by IB3-1 to the levels produced by C38. These data suggest that 3O-C12 induces proinflammatory
cytokine production in airway epithelial cells in a
calcium-dependent manner, and that dysregulated
calcium storage or signalling in CF cells results in an increased production of proinflammatory
cytokines.