In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 99, No. 18 ( 2002-09-03), p. 11599-11604
Kurzfassung:
1-Cys peroxiredoxin (1-cysPrx) is a novel antioxidant enzyme able to reduce phospholipid hydroperoxides in vitro by using glutathione as a reductant. This enzyme is widely expressed and is enriched in lungs. A fusion protein of green fluorescent protein with 1-cysPrx was stably expressed in a lung-derived cell line (NCI-H441) lacking endogenous enzyme. Overexpressing cells (C17 or C48) degraded H 2 O 2 and t -butylhydroperoxide more rapidly and showed decreased sensitivity to oxidant stress as measured by 51 Cr release. On exposure to • OH generated by Cu 2+ -ascorbate (Asc), overexpressing cells compared with H441 showed less increase in thiobarbituric acid-reactive substance and phosphatidylcholine hydroperoxide content. This effect was reversed by depletion of cellular glutathione. Diphenyl-1-pyrenoylphosphonium fluorescence, used as a real-time probe of membrane phospholipid peroxidation, increased immediately on exposure to Cu 2+ -Asc and was abolished by preincubation of cells with Trolox (a soluble vitamin E) or Tempol (a radical scavenger). The rate of diphenyl-1-pyrenoylphosphonium fluorescence increase with Cu 2+ -Asc exposure was markedly attenuated in C17 and C48 cells as compared with H441. Annexin V-Cy3 was used to detect phosphatidylserine translocation from the inner to outer leaflet of the plasma membrane. Cu 2+ -Asc treatment induced phosphatidylserine translocation within 2 h in H441 cells but none was observed in C48 cells up to 24 h. These results indicate that 1-cysPrx can scavenge peroxides but in addition can reduce peroxidized membrane phospholipids. Thus, the enzyme can protect cells against oxidant-induced plasma membrane damage, thereby playing an important role in cellular defense against oxidant stress.
Materialart:
Online-Ressource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.182384499
Sprache:
Englisch
Verlag:
Proceedings of the National Academy of Sciences
Publikationsdatum:
2002
ZDB Id:
209104-5
ZDB Id:
1461794-8
SSG:
11
SSG:
12
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