In:
Journal of Cellular and Molecular Medicine, Wiley, Vol. 13, No. 8b ( 2009-08-02), p. 2200-2209
Abstract:
In this study, we aimed to determine the contribution of peroxynitrite‐dependent sulfhydryl group (SH) oxidation to the contractile dysfunction in permeabilized left ventricular human cardiomyocytes using a comparative approach with the SH‐oxidant 2,2′‐dithiodipyridine (DTDP). Additionally, different antioxidants: dithiothreitol (DTT), reduced glutathione (GSH) or N‐acetyl‐L‐cysteine (NAC) were employed to test reversibility. Maximal isometric active force production ( F o ) and the maximal turnover rate of the cross‐bridge cycle ( k tr,max ) illustrated cardiomyocyte mechanics. SH oxidation was monitored by a semi‐quantitative Ellman’s assay and by SH‐specific protein biotinylation. Both peroxynitrite and DTDP diminished F o in a concentration‐dependent manner (EC 50,peroxynitrite = 49 μM; EC 50,DTDP = 2.75 mM). However, k tr,max was decreased only by 2.5‐mM DTDP, but not by 50 μM peroxynitrite. The diminution of F o to zero by DTDP was paralleled by the complete elimination of the free SH groups, while the peroxynitrite‐induced maximal reduction in free SH groups was only to 58 ± 6% of the control (100%). The diminutions in F o and free SH groups evoked by 2.5‐mM DTDP were completely reverted by DTT. In contrast, DTT induced only a partial restoration in F o (Δ F o, :∼13%; P 〈 0.05) despite full reversion in protein SH content after 50 μM peroxynitrite. Although, NAC or DTT were equally effective on F o after peroxynitrite exposures, NAC or GSH did not restore F o or k tr,max after DTDP treatments. Our results revealed that the peroxynitrite‐evoked cardiomyocyte dysfunction has a small, but significant component resulting from reversible SH oxidation, and thereby illustrated the potential benefit of antioxidants during cardiac pathologies with excess peroxynitrite production.
Type of Medium:
Online Resource
ISSN:
1582-1838
,
1582-4934
DOI:
10.1111/jcmm.2009.13.issue-8b
DOI:
10.1111/j.1582-4934.2008.00445.x
Language:
English
Publisher:
Wiley
Publication Date:
2009
detail.hit.zdb_id:
2076114-4
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