| 1. |
- Abdiu, Avni, 1963-, et al.
(författare)
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Thioredoxin blood level increases after severe burn injury
- 2000
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Ingår i: Antioxidants and Redox Signaling. - 1523-0864 .- 1557-7716. ; 2:4, s. 707-716
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the thioredoxin (TRX) levels in severely burned patients and the possible origin of TRX, based on the recent understanding that TRX is a potent antioxidant with cytoprotective functions. Serum and plasma samples from burns patients and healthy blood donors were collected during the first 10 post-bum days and analyzed in a sandwich TRX enzyme-linked immunosorbent assay (ELISA). The TRX levels found were correlated to a panel of blood tests. The presence of TRX in platelets was investigated by immunoelectron microscopy and Western blotting. TRX serum levels of the severely burned patients showed a significant increase, with a mean serum TRX concentration on the day of injury of 76.5 ▒ 19.5 ng/ml (mean ▒ SD) and on post-burn day one 122.6 ▒ 66.9 ng/ml, compared to control blood donor levels of 22.7 ▒ 12.2 ng/ml (p = 0.0041 and 0.0117, respectively). A second peak of increase was found on post-burn days 7 to 9 with a four- to five-fold rise in concentration compared to controls. TRX elevation correlated well with increased platelet (p = 0.007) and leukocyte counts (p = 0.002). We also demonstrated by immunoelectron microscopy and Western blotting the presence of TRX in platelets. In conclusion, our demonstration of TRX release in burn injuries indicates that the TRX system is involved in a rapid antioxidant defense, coagulation processes, cell growth, and control of the extracellular peroxide tone intimately linked to cytoprotection and wound healing in burns. One of the cell types that delivers TRX promptly and efficiently into the blood may be the platelet.
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| 2. |
- Arnér, Elias S. J., et al.
(författare)
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Analysis of the inhibition of mammalian thioredoxin, thioredoxin reductase, and glutaredoxin by cis-diamminedichloroplatinum (II) and its major metabolite, the glutathione-platinum complex
- 2001
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Ingår i: Free Radical Biology & Medicine. - : Elsevier. - 0891-5849 .- 1873-4596. ; 31:10, s. 1170-1178
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Tidskriftsartikel (refereegranskat)abstract
- Several studies have demonstrated a correlation between cellular toxicity of cis-diamminedichloroplatinum (II) (cisplatin, CDDP) and inhibited intracellular activity of the thioredoxin system, i.e., thioredoxin (Trx), thioredoxin reductase (TrxR), and NADPH. Conversely, increased cellular activity of the Trx system confers resistance to CDDP. In this study, we have analyzed the interaction of CDDP with Trx and TrxR in order to clarify the mechanism. The inhibition with time-dependent kinetics by CDDP of NADPH-reduced (but not oxidized) TrxR was irreversible, strongly suggesting covalent modification of the reduced selenocysteine-containing active site. Assuming second order kinetics, the rate constant of TrxR inhibition by CDDP was 21 +/- 3 M(-1) x s(-1). Transplatin was found to be an even more efficient inhibitor, with a second order rate constant of 84 +/- 22 M(-1) x s(-1), whereas carboplatin (up to 1 mM) gave no inhibition of the enzyme under the same conditions. Escherichia coli Trx or human or bacterial glutaredoxin (Grx) activities were in comparison only slightly or not at all inhibited by either CDDP, transplatin, or carboplatin. However, glutaredoxins were found to be inhibited by the purified glutathione adduct of cisplatin, bis-(glutathionato)platinum(II) (GS-Platinum complex, GS-Pt), with an IC50 = 350 microM in the standard beta-hydroxyethyl disulfide-coupled assay for human Grx. Also the mammalian Trx system was inhibited by GS-Pt with similar efficiency (IC(50) = 325 microM), whereas neither the E. coli Trx system nor glutathione reductase were inhibited. Formation of GS-Pt is a major route for cellular elimination of CDDP. The fact that GS-Pt inhibits the mammalian Trx as well as Grx systems shows that CDDP may exert effects at several stages of its metabolism, including after conjugation with GSH, which are intimately linked with the cellular disulfide/dithiol redox regulatory systems.
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| 3. |
- Tanaka, Toru, et al.
(författare)
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Thioredoxin-2 (TRX-2) is an essential gene regulating mitochondria-dependent apoptosis
- 2002
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Ingår i: EMBO Journal. - : Wiley-Blackwell. - 0261-4189 .- 1460-2075. ; 21:7, s. 1695-703
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Tidskriftsartikel (refereegranskat)abstract
- Thioredoxin-2 (Trx-2) is a mitochondria-specific member of the thioredoxin superfamily. Mitochondria have a crucial role in the signal transduction for apoptosis. To investigate the biological significance of Trx-2, we cloned chicken TRX-2 cDNA and generated clones of the conditional Trx-2-deficient cells using chicken B-cell line, DT40. Here we show that TRX-2 is an essential gene and that Trx-2-deficient cells undergo apoptosis upon repression of the TRX-2 transgene, showing an accumulation of intracellular reactive oxygen species (ROS). Cytochrome c is released from mitochondria, while caspase-9 and caspase-3, but not caspase-8, are activated upon inhibition of the TRX-2 transgene. In addition, Trx-2 and cytochrome c are co-immunoprecipitated in an in vitro assay. These results suggest that mitochondrial Trx-2 is essential for cell viability, playing a crucial role in the scavenging ROS in mitochondria and regulating the mitochondrial apoptosis signaling pathway.
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