Paraoxonase 2 is down-regulated by the Pseudomonas aeruginosa quorumsensing signal N-(3-oxododecanoyl)-L -homoserine lactone and attenuates oxidative stress induced by pyocyanin
| Autor: | Petra Wilgenbus, Marion Goldeck, Sebastian Altenhöfer, Puneet K. Chowdhary, John F. Teiber, Donovan C. Haines, Gerald L. Kramer, Ulrich Förstermann, Junhui Xiao, Ines Witte, Sven Horke, Robert W. Haley |
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| Rok vydání: | 2010 |
| Předmět: |
Small interfering RNA
Cell Survival Blotting Western Down-Regulation Virulence Biology medicine.disease_cause Biochemistry Cell Line chemistry.chemical_compound Pyocyanin 4-Butyrolactone Homoserine Lactonase medicine Humans RNA Small Interfering Molecular Biology Calcimycin chemistry.chemical_classification Reactive oxygen species Gene knockdown Aryldialkylphosphatase Pseudomonas aeruginosa Quorum Sensing Biological Transport Cell Biology Cell biology Enzyme Activation Oxidative Stress chemistry Pyocyanine biology.protein Calcium Oxidative stress |
| Zdroj: | Biochemical Journal. 426:73-83 |
| ISSN: | 1470-8728 0264-6021 |
| Popis: | Two virulence factors produced by Pseudomonas aeruginosa are pyocyanin and N-(3-oxododecanoyl)-L-homoserine lactone (3OC12). Pyocyanin damages host cells by generating ROS (reactive oxygen species). 3OC12 is a quorum-sensing signalling molecule which regulates bacterial gene expression and modulates host immune responses. PON2 (paraoxonase-2) is an esterase that inactivates 3OC12 and potentially attenuates Ps. aeruginosa virulence. Because increased intracellular Ca2+ initiates the degradation of PON2 mRNA and protein and 3OC12 causes increases in cytosolic Ca2+, we hypothesized that 3OC12 would also down-regulate PON2. 3OC12 and the Ca2+ ionophore A23187 caused a rapid cytosolic Ca2+ influx and down-regulated PON2 mRNA, protein and hydrolytic activity in A549 and EA.hy 926 cells. The decrease in PON2 hydrolytic activity was much more extensive and rapid than decreases in protein, suggesting a rapid post-translational mechanism which blocks PON2's hydrolytic activity. The Ca2+ chelator BAPTA/AM [1,2-bis-(o-aminophenoxy)ethane-N,N,N′,N′-tetra-acetic acid tetrakis(acetoxymethyl ester)] diminished the ability of 3OC12 to decrease PON2, demonstrating that the effects are mediated by Ca2+. PON2 also has antioxidative properties and we show that it protects cells from pyocyanin-induced oxidative stress. Knockdown of PON2 by transfecting cells with siRNA (small interfering RNA) rendered them more sensitive to, whereas overexpression of PON2 protected cells from, pyocyanin-induced ROS formation. Additionally, 3OC12 potentiated pyocyanin-induced ROS formation, presumably by inactivating PON2. These findings support a key role for PON2 in the defence against Ps. aeruginosa virulence, but also reveal a mechanism by which the bacterium may subvert the protection afforded by PON2. |
| Databáze: | OpenAIRE |
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