Skip to Content
Merck
  • The Pseudomonas toxin pyocyanin inhibits the dual oxidase-based antimicrobial system as it imposes oxidative stress on airway epithelial cells.

The Pseudomonas toxin pyocyanin inhibits the dual oxidase-based antimicrobial system as it imposes oxidative stress on airway epithelial cells.

Journal of immunology (Baltimore, Md. : 1950) (2008-09-20)
Balázs Rada, Kristen Lekstrom, Sorin Damian, Corinne Dupuy, Thomas L Leto
ABSTRACT

The dual oxidase-thiocyanate-lactoperoxidase (Duox/SCN(-)/LPO) system generates the microbicidal oxidant hypothiocyanite in the airway surface liquid by using LPO, thiocyanate, and Duox-derived hydrogen peroxide released from the apical surface of the airway epithelium. This system is effective against several microorganisms that infect airways of cystic fibrosis and other immunocompromised patients. We show herein that exposure of airway epithelial cells to Pseudomonas aeruginosa obtained from long-term cultures inhibits Duox1-dependent hydrogen peroxide release, suggesting that some microbial factor suppresses Duox activity. These inhibitory effects are not seen with the pyocyanin-deficient P. aeruginosa strain PA14 Phz1/2. We show that purified pyocyanin, a redox-active virulence factor produced by P. aeruginosa, inhibits human airway cell Duox activity by depleting intracellular stores of NADPH, as it generates intracellular superoxide. Long-term exposure of human airway (primary normal human bronchial and NCI-H292) cells to pyocyanin also blocks induction of Duox1 by Th2 cytokines (IL-4, IL-13), which was prevented by the antioxidants glutathione and N-acetylcysteine. Furthermore, we showed that low concentrations of pyocyanin blocked killing of wild-type P. aeruginosa by the Duox/SCN(-)/LPO system on primary normal human bronchial epithelial cells. Thus, pyocyanin can subvert Pseudomonas killing by the Duox-based system as it imposes oxidative stress on the host. We also show that lactoperoxidase can oxidize pyocyanin, thereby diminishing its cytotoxicity. These data establish a novel role for pyocyanin in the survival of P. aeruginosa in human airways through competitive redox-based reactions between the pathogen and host.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Bovine Serum Albumin, lyophilized powder, crystallized, ≥98.0% (GE)
Sigma-Aldrich
Bovine Serum Albumin, lyophilized powder, essentially γ-globulin free, ≥98% (agarose gel electrophoresis)
Sigma-Aldrich
Bovine Serum Albumin, heat shock fraction, protease free, fatty acid free, essentially globulin free, pH 7, ≥98%
Sigma-Aldrich
Bovine Serum Albumin, heat shock fraction, low endotoxin, pH 7, ≥98%
Sigma-Aldrich
Bovine Serum Albumin, lyophilized powder, essentially globulin free, low endotoxin, ≥98% (agarose gel electrophoresis)
Sigma-Aldrich
Bovine Serum Albumin, heat shock fraction, low endotoxin, pH 7, ≥98%
Sigma-Aldrich
Bovine Serum Albumin, heat shock fraction, pH 5.2, ≥96%
Sigma-Aldrich
Bovine Serum Albumin, heat shock fraction, pH 7, ≥98%
Sigma-Aldrich
Bovine Serum Albumin, heat shock fraction, protease free, pH 7, ≥98%
Sigma-Aldrich
Bovine Serum Albumin, heat shock fraction, suitable for RIA, pH 5.2, ≥96%
Sigma-Aldrich
Bovine Serum Albumin, lyophilized powder, essentially fatty acid free, ≥97% (agarose gel electrophoresis), 1X Crystallized
Sigma-Aldrich
Bovine Serum Albumin, cold ethanol fraction, pH 5.2, ≥96%
Sigma-Aldrich
Bovine Serum Albumin, heat shock fraction, pH 7, ≥98%
Sigma-Aldrich
Bovine Serum Albumin, lyophilized powder, essentially IgG free, ≥96% (agarose gel electrophoresis)
Sigma-Aldrich
Bovine Serum Albumin, lyophilized powder, ≥96% (agarose gel electrophoresis)
Sigma-Aldrich
Bovine Serum Albumin, lyophilized powder, essentially globulin free, BioReagent, suitable for cell culture
Sigma-Aldrich
Bovine Serum Albumin, heat shock fraction, microbiologically tested, ≥96% (agarose gel electrophoresis)
Sigma-Aldrich
Bovine Serum Albumin, dimer mol wt ~132 kDa
Sigma-Aldrich
Bovine Serum Albumin, heat shock fraction, protease free, low endotoxin, suitable for cell culture, pH 7, ≥98%
Sigma-Aldrich
Bovine Serum Albumin, lyophilized powder, suitable for (for molecular biology), Non-acetylated
Sigma-Aldrich
Bovine Serum Albumin, lyophilized powder, γ-irradiated, Globulin Free, BioXtra, suitable for cell culture
Sigma-Aldrich
Bovine Serum Albumin, heat shock fraction, protease free, essentially globulin free, pH 7, ≥98%
Sigma-Aldrich
Bovine Serum Albumin, lyophilized powder, BioReagent, suitable for cell culture
Sigma-Aldrich
Bovine Serum Albumin, lyophilized powder, 1× crystallized, ≥97% (agarose gel electrophoresis)
Sigma-Aldrich
Bovine Serum Albumin, lyophilized powder, essentially globulin free, ≥99% (agarose gel electrophoresis)
Sigma-Aldrich
Bovine Serum Albumin, heat shock fraction, lyophilized powder, essentially fatty acid free, ≥98% (agarose gel electrophoresis)
Sigma-Aldrich
Bovine Serum Albumin, For use as a marker in SDS-PAGE
Sigma-Aldrich
Bovine Serum Albumin, heat shock fraction, protease free, suitable for hybridization, pH 7, ≥98%
Sigma-Aldrich
Bovine Serum Albumin, pH <5.0, powder
Sigma-Aldrich
Bovine Serum Albumin, lyophilized powder, ≥96% (agarose gel electrophoresis)