Characterization of hydrogen peroxide production by Duox in bronchial epithelial cells exposed to Pseudomonas aeruginosa

Abstract 

Hydrogen peroxide production by the NADPH oxidase Duox1 occurs during activation of respiratory epithelial cells stimulated by purified bacterial ligands, such as lipopolysaccharide. Here, we characterize Duox activation using intact bacterial cells of several airway pathogens. We found that only Pseudomonas aeruginosa, not Burkholderia cepacia or Staphylococcus aureus, triggers H₂O₂ production in bronchial epithelial cells in a calcium-dependent but predominantly ATP-independent manner. Moreover, by comparing mutant Pseudomonas strains, we identify several virulence factors that participate in Duox activation, including the type-three secretion system. These data provide insight on Duox activation by mechanisms unique to P. aeruginosa.

Abbreviations: ALI, air–liquid interface, ASL, airway surface liquid, CF, cystic fibrosis, CFTR, cystic fibrosis transmembrane conductance regulator, DPI, diphenylene iodonium, Duox, dual oxidase, H₂O₂, hydrogen peroxide, HRP, horse-radish peroxidase, HTBE, human tracheobronchial epithelial cells, LPS, lipopolysaccharide, Nox, NADPH oxidase, OSCN⁻, hypothiocyanite, RLU, relative luminescence unit, RT, reverse transcription, SCN⁻, thiocyanate, TLR, toll-like receptor, T3SS, type-three secretion system

Keywords: NADPH oxidase, Hydrogen peroxide, Duox, Dual oxidase, Epithelial cell, Pseudomonas