Oxidant stress during simulated ischemia primes cardiomyocytes for cell death during reperfusion

Emmanuel Robin, Robert D. Guzy, Gabriel Loor, Hirotaro Iwase, Gregory B. Waypa, Jeremy D. Marks, Terry L. Vanden Hoek, Paul T. Schumacker*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

108 Scopus citations

Abstract

Ischemia-reperfusion injury induces oxidant stress, and the burst of reactive oxygen species (ROS) production after reperfusion of ischemic myocardium is sufficient to induce cell death. Mitochondrial oxidant production may begin during ischemia prior to reperfusion because reducing equivalents accumulate and promote superoxide production. We utilized a ratiometric redox-sensitive protein sensor (heat shock protein 33 fluorescence resonance energy transfer (HSP-FRET)) to assess oxidant stress in cardiomyocytes during simulated ischemia. HSP-FRET consists of the cyan and yellow fluorescent protein fluorophores linked by the cysteine-containing regulatory domain from bacterial HSP-33. During ischemia, ROS-mediated oxidation of HSP-FRET was observed, along with a decrease in cellular reduced glutathione levels. These findings were corroborated by measurements using redox-sensitive green fluorescent protein, another protein thiol ratiometric sensor, which became 93% oxidized by the end of simulated ischemia. However, cell death did not occur during ischemia, indicating that this oxidant stress is not sufficient to induce death before reperfusion. However, interventions that attenuate ischemic oxidant stress, including antioxidants or scavengers of residual O2 that attenuate/prevent ROS generation during ischemia, abrogated cell death during simulated reperfusion. These findings reveal that, in isolated cardiomyocytes, sublethal H2O2 generation during simulated ischemia regulates cell death during simulated reperfusion, which is mediated by the reperfusion oxidant burst.

Original languageEnglish (US)
Pages (from-to)19133-19143
Number of pages11
JournalJournal of Biological Chemistry
Volume282
Issue number26
DOIs
StatePublished - Jun 29 2007

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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