Possible role of bacterial siderophores in inflammation. Iron bound to the Pseudomonas siderophore pyochelin can function as a hydroxyl radical catalyst.

Coffman, Thomas J.; Cox, Charles D.; Edeker, Brian L.; Britigan, Bradley E.

doi:10.1172/jci114805

Cited by 67 publications

(55 citation statements)

References 61 publications

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“…The strong inhibitory activity of V-PCH, and the fact that both V(IV) and V(V) were detected in association with PCH, were strongly suggestive of V-PCH undergoing a redox cycle which could result in the generation of toxic superoxide anions (O − # ), as already described for ferripyochelin (Coffman et al, 1990 ;Britigan et al, 1997). On the other hand, it is well known that V(IV) can auto-oxidize in neutral aqueous solutions, yielding O − # and vanadate (Liochev & Fridovich, 1987).…”

Section: Effect Of Vanadium On Resistance Of P Aeruginosa To Paraquatsupporting

confidence: 67%

“…This result suggests that V-PCH can undergo an oxidative cycle that can result in the generation of superoxide radicals (O − # ). It is well known that ferripyochelin can undergo such a redox cycle, resulting in the production of cell-damaging active oxygen species (Coffman et al, 1990 ;Britigan et al, 1997). Stern et al (1992) also demonstrated that V(IV)-desferrioxamine has a redoxcycling activity and generates active oxygen species.…”

Section: Discussionmentioning

confidence: 99%

“…Protochelin is a tri-catecholate with the highest affinity for iron and is produced only under conditions of extreme oxygen stress. Like protochelin, PVD from P. aeruginosa can form a 1 : 1 complex with iron and protect the cells from oxidative damage due to the Fenton reaction (Coffman et al, 1990). Indeed, these authors showed that O − # could reduce and release iron bound to Fe-PCH but not Fe-PVD.…”

Section: Discussionmentioning

confidence: 99%

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Vanadium interferes with siderophore-mediated iron uptake in Pseudomonas aeruginosa

et al. 2000

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Vanadium is a metal that under physiological conditions can exist in two oxidation states, V(IV) (vanadyl ion) and V(V) (vanadate ion).Here, it was demonstrated that both ions can form complexes with siderophores. Pseudomonas aeruginosa produces two siderophores under iron-limiting conditions, pyoverdine (PVD) and pyochelin (PCH). Vanadyl sulfate, at a concentration of 1-2 mM, strongly inhibited growth of P. aeruginosa PAO1, especially under conditions of severe iron limitation imposed by the presence of non-utilizable Fe(III) chelators. PVD-deficient mutants were more sensitive to vanadium than the wild-type, but addition of PVD did not stimulate their growth. Conversely, PCH-negative mutants were more resistant to vanadium than the wild-type strain. Both siderophores could bind and form complexes with vanadium after incubation with vanadyl sulfate (1 :1, in the case of PVD ; :1, in the case of PCH). Although only one complex with PVD, V(IV)-PVD, was found, both V(IV)-and V(V)-PCH were detected. V-PCH, but not V-PVD, causedstrong growth reduction, resulting in a prolonged lag phase. Exposure of PAO1 cells to vanadium induced resistance to the superoxide-generating compound paraquat, and conversely, exposure to paraquat increased resistance to V(IV). Superoxide dismutase (SOD) activity of cells grown in the presence of V(IV) was augmented by a factor of two. Mutants deficient in the production of Fe-SOD (SodB) were particularly sensitive to vanadium, whilst sodA mutants deficient for Mn-SOD were only marginally affected. In conclusion, it is suggested that V-PCH catalyses a Fenton-type reaction whereby the toxic superoxide anion O N 2 is generated, and that vanadium compromises PVD utilization.

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Section: Effect Of Vanadium On Resistance Of P Aeruginosa To Paraquatsupporting

confidence: 67%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Vanadium interferes with siderophore-mediated iron uptake in Pseudomonas aeruginosa

et al. 2000

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“…Recently, we found that iron bound to the P. aeruginosa siderophore pyochelin was capable of catalyzing the formation of hydroxyl radical from a continuous flux of 0 /H202 generated by stimulated neutrophils or a cell-free enzymatic system (21 ). These data suggested that ferripyochelin might contribute to Pseudomonas-mediated tissue injury via the generation of cytotoxic hydroxyl radical.…”

Section: Introductionmentioning

confidence: 94%

Interaction of the Pseudomonas aeruginosa secretory products pyocyanin and pyochelin generates hydroxyl radical and causes synergistic damage to endothelial cells. Implications for Pseudomonas-associated tissue injury.

Britigan¹,

Roeder²,

Rasmussen³

et al. 1992

J. Clin. Invest.

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135

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IntroductionPyocyanin, a secretory product of Pseudomonas aeruginosa, has the capacity to undergo redox cycling under aerobic conditions with resulting generation of superoxide and hydrogen peroxide. By using spin trapping techniques in conjunction with electron paramagnetic resonance spectrometry (EPR), superoxide was detected during the aerobic reduction of pyocyanin by NADH or porcine endothelial cells. No evidence of hydroxyl radical formation was detected. Chromium oxalate eliminated the EPR spectrum of the superoxide-derived spin adduct resulting from endothelial cell exposure to pyocyanin, suggesting superoxide formation close to the endothelial cell plasma membrane. We have previously reported that iron bound to the P. aeruginosa siderophore pyochelin (ferripyochelin) catalyzes the formation of hydroxyl free radical from superoxide and hydrogen peroxide via the Haber-Weiss reaction. In the present study, spin trap evidence of hydroxyl radical formation was detected when NADH and pyocyanin were allowed to react in the presence of ferripyochelin. Similarly, endothelial cell exposure to pyocyanin and ferripyochelin also resulted in hydroxyl radical production which appeared to occur in close proximity to the cell surface. As assessed by 51Cr release, endothelial cells which were treated with pyocyanin or ferripyochelin alone demonstrated minimal injury. However, endothelial cell exposure to the combination of pyochelin and pyocyanin resulted in 55% specific 51Cr release. Injury was not observed with the substitution of iron-free pyochelin and was diminished by the presence of catalase or dimethyl thiourea. These data suggest the possibility that the P. aeruginosa secretory products pyocyanin and pyochelin may act synergistically via the generation of hydroxyl radical to damage local tissues at sites of pseudomonas infection. (J. Clin. Invest. 1992. 90:2187-2196

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“…Pyochelin stimulates bacterial growth in murine infections (9), reverses iron deprivation caused by human serum and transferrin (1), and efficiently removes iron from transferrin (42). Fe(III)-pyochelin is capable of catalyzing hydroxyl radical formation (6) and may play a role in the tissue destruction associated with Pseudomonas infections (41). Mutants with defects in pyochelin-mediated Fe(III) transport were observed to be markedly less virulent than wildtype strains of P. aeruginosa (35).…”

mentioning

confidence: 99%

Cloning of the outer membrane high-affinity Fe(III)-pyochelin receptor of Pseudomonas aeruginosa

Ankenbauer

1992

J Bacteriol

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Possible role of bacterial siderophores in inflammation. Iron bound to the Pseudomonas siderophore pyochelin can function as a hydroxyl radical catalyst.

Cited by 67 publications

References 61 publications

Vanadium interferes with siderophore-mediated iron uptake in Pseudomonas aeruginosa

Vanadium interferes with siderophore-mediated iron uptake in Pseudomonas aeruginosa

Interaction of the Pseudomonas aeruginosa secretory products pyocyanin and pyochelin generates hydroxyl radical and causes synergistic damage to endothelial cells. Implications for Pseudomonas-associated tissue injury.

Cloning of the outer membrane high-affinity Fe(III)-pyochelin receptor of Pseudomonas aeruginosa

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