The critical role of intracellular zinc in adenosine A2 receptor activation induced cardioprotection against reperfusion injury

McIntosh, Rachel; Lee, SungRyul; Ghio, Andrew J.; Xi, Jinkun; Zhu, Min; Shen, Xiangjun; Chanoit, Guillaume; Zvara, David A.; Xu, Zhelong

doi:10.1016/j.yjmcc.2010.02.001

« Previous Next »Journal of Molecular and Cellular Cardiology
Volume 49, Issue 1 , Pages 41-47, July 2010

The critical role of intracellular zinc in adenosine A₂ receptor activation induced cardioprotection against reperfusion injury

Rachel McIntosh
- Department of Anesthesiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- These authors contributed equally to this work.
SungRyul Lee
- Department of Anesthesiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- These authors contributed equally to this work.
Andrew J. Ghio
- Human Studies Division, US Environmental Protection Agency, Chapel Hill, NC 27599, USA
- These authors contributed equally to this work.
Jinkun Xi
- Department of Anesthesiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
Min Zhu
- Department of Anesthesiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
Xiangjun Shen
- Department of Anesthesiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
Guillaume Chanoit
- Department of Anesthesiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
David A. Zvara
- Department of Anesthesiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
Zhelong Xu
- Department of Anesthesiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Corresponding author. Tel.: +1 919 843 4174.

Received 14 October 2009; received in revised form 26 January 2010; accepted 1 February 2010. published online 08 February 2010.

Abstract

Exogenous zinc can protect cardiac cells from reperfusion injury, but the exact roles of endogenous zinc in the pathogenesis of reperfusion injury and in adenosine A₂ receptor activation-induced cardioprotection against reperfusion injury remain unknown. Adenosine A₁/A₂ receptor agonist 5′-(N-ethylcarboxamido) adenosine (NECA) given at reperfusion reduced infarct size in isolated rat hearts subjected to 30min ischemia followed by 2h of reperfusion. This effect of NECA was partially but significantly blocked by the zinc chelator N,N,N′,N′-tetrakis-(2-pyridylmethyl) ethylenediamine (TPEN), and ZnCl₂ given at reperfusion mimicked the effect of NECA by reducing infarct size. Total tissue zinc concentrations measured with inductively coupled plasma optical emission spectroscopy (ICPOES) were decreased upon reperfusion in rat hearts and this was reversed by NECA. NECA increased intracellular free zinc during reperfusion in the heart. Confocal imaging study showed a rapid increase in intracellular free zinc in isolated rat cardiomyocytes treated with NECA. Further experiments revealed that NECA increased total zinc levels upon reperfusion in mitochondria isolated from isolated hearts. NECA attenuated mitochondrial swelling upon reperfusion in isolated hearts and this was inhibited by TPEN. Similarly, NECA prevented the loss of mitochondrial membrane potential (ΔΨm) caused by oxidant stress in cardiomyocytes. Finally, both NECA and ZnCl₂ inhibited the mitochondrial metabolic activity. NECA-induced cardioprotection against reperfusion injury is mediated by intracellular zinc. NECA prevents reperfusion-induced zinc loss and relocates zinc to mitochondria. The inhibitory effects of zinc on both the mPTP opening and the mitochondrial metabolic activity may account for the cardioprotective effect of NECA.