• Open Access

Identification of protein targets underlying dietary nitrate-induced protection against doxorubicin cardiotoxicity

Authors

  • Lei Xi,

    Corresponding author
    1. VCU Pauley Heart Center, Division of Cardiology, Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA
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  • Shu-Guang Zhu,

    1. VCU Pauley Heart Center, Division of Cardiology, Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA
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  • Daniel C. Hobbs,

    1. VCU Pauley Heart Center, Division of Cardiology, Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA
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  • Rakesh C. Kukreja

    1. VCU Pauley Heart Center, Division of Cardiology, Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA
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Lei XI, M.D., Division of Cardiology, Box 980204, Virginia Commonwealth University, 1101 East Marshall Street, Room 7-020C, Richmond, VA 23298-0204, USA. Tel.: (804)-628-5533 Fax: (804)-828-8700 E-mail: lxi@vcu.edu

Abstract

We recently demonstrated protective effect of chronic oral nitrate supplementation against cardiomyopathy caused by doxorubicin (DOX), a highly effective anticancer drug. The present study was designed to identify novel protein targets related to nitrate-induced cardioprotection. Adult male CF-1 mice received cardioprotective regimen of nitrate (1 g NaNO3 per litre of drinking water) for 7 days before DOX injection (15 mg/kg, i.p.) and continued for 5 days after DOX treatment. Subsequently the heart samples were collected for proteomic analysis with two-dimensional differential in-gel electrophoresis with 3 CyDye labelling. Using 1.5 cut-off ratio, we identified 36 proteins that were up-regulated by DOX in which 32 were completely reversed by nitrate supplementation (89%). Among 19 proteins down-regulated by DOX, 9 were fully normalized by nitrate (47%). The protein spots were further identified with Matrix Assisted Laser Desorption/Ionization-Time-of-Flight (MALDI-TOF)/TOF tandem mass spectrometry. Three mitochondrial antioxidant enzymes were altered by DOX, i.e. up-regulation of manganese superoxide dismutase and peroxiredoxin 3 (Prx3), and down-regulation of Prx5, which were reversed by nitrate. These results were further confirmed by Western blots. Nitrate supplementation also significantly improved animal survival rate from 80% in DOX alone group to 93% in Nitrate + DOX group 5 days after the DOX treatment. In conclusion, the proteomic analysis has identified novel protein targets underlying nitrate-induced cardioprotection. Up-regulation of Prx5 by nitrate may explain the observed enhancement of cardiac antioxidant defence by nitrate supplementation.

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