title: Pyocyanin induces oxidative stress in human endothelial cells and modulates the glutathione redox cycle.
abstract: Pyocyanin is a redox active virulence factor produced by the human pathogen Pseudomonas aeruginosa. Treatment of endothelial cells with pyocyanin (1-50 microM) resulted in the dose-dependent formation of hydrogen peroxide that was detected in the extracellular medium. Total intracellular glutathione levels decreased in response to pyocyanin in a dose-dependent manner from a control value of 19.9 +/- 2.7 nmol/mg protein to 10.0 +/- 2.4 nmol/mg protein. Prior treatment of cells with catalase afforded complete protection against loss of glutathione. Total intracellular soluble thiols decreased from 95.0 +/- 6.2 nmol/mg protein to 78.6 +/- 2.3 nmol/mg protein at the highest test dose. Intracellular levels of NADPH increased up to 2.4-fold in response to pyocyanin exposure. It is concluded that pyocyanin exposes endothelial cells to oxidative stress by the generation of hydrogen peroxide, which subsequently depletes intracellular glutathione and increases intracellular levels of mixed disulfides.
authors.affiliation: Centre for Infectious Diseases, University of Sydney, Westmead Hospital, Westmead, NSW, Australia. mmuller@med.usyd.edu.au
authors.forename: Michael
authors.initials: M
authors.lastname: Muller
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D002470:Cell Survival; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D005609:Free Radicals; D005978:Glutathione / Q000737:chemistry / Q000378:metabolism*; D005980:Glutathione Reductase / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology; D008956:Models, Chemical; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D011550:Pseudomonas aeruginosa / Q000378:metabolism; D011710:Pyocyanine / Q000737:chemistry* / Q000494:pharmacology*; D017382:Reactive Oxygen Species; D013997:Time Factors; D014471:Umbilical Veins / Q000166:cytology
chemical_list: D000900:Anti-Bacterial Agents; D005609:Free Radicals; D017382:Reactive Oxygen Species; D009249:NADP; D011710:Pyocyanine; D006861:Hydrogen Peroxide; D005980:Glutathione Reductase; D005978:Glutathione