Novel mechanisms of myocardial ischemia, ischemia-reperfusion, and protection by myocardial conditioning: Infarct size-limiting effect of epoxyeicosatrienoic acid analog EET-B is mediated by hypoxia-inducible factor-1α via downregulation of prolyl hydroxylase 3

Jan Neckář, Anna Hsu, Md Abdul Hye Khan, Garrett J. Gross, Kasem Nithipatikom, Michaela Cyprová, Daniel Benák, Markéta Hlaváčková, Dita Sotáková-Kašparová, J R Falck, David Sedmera, František Kolář, John D. Imig

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Epoxyeicosatr-ienoic acids (EETs) decrease cardiac ischemia-reperfusion injury; however, the mechanism of their protective effect remains elusive. Here, we investigated the cardioprotective action of a novel EET analog, EET-B, in reperfusion and the role of hypoxia-inducible factor (HIF)-1β in such action of EET-B. Adult male rats were subjected to 30 min of left coronary artery occlusion followed by 2h of reperfusion. Administration of 14,15-EET (2.5 mg/kg) or EET-B (2.5 mg/kg) 5 min before reperfusion reduced infarct size expressed as a percentage of the area at risk from 64.3 ± 1.3% in control to 42.6 ± 1.9% and 46.0 ± 1.6%, respectively, and their coadministration did not provide any stronger effect. The 14,15-EET antagonist 14,15-epoxyei-cosa-5(Z)-enoic acid (2.5 mg/kg) inhibited the infarct size-limiting effect of EET-B (62.5 ± 1.1%). Similarly, the HIF-1β inhibitors 2-methoxyestradiol (2.5 mg/kg) and acriflavine (2 mg/kg) completely abolished the cardioprotective effect of EET-B. In a separate set of experiments, the immunoreactivity of HIF-1β and its degrading enzyme prolyl hydroxylase domain protein 3 (PHD3) were analyzed in the ischemic areas and nonischemic septa. At the end of ischemia, the HIF-1β immunogenic signal markedly increased in the ischemic area compared with the septum (10.31 ± 0.78% vs. 0.34 ± 0.08%). After 20 min and 2 h of reperfusion, HIF-1β immunoreactivity decreased to 2.40 ± 0.48% and 1.85 ± 0.43%, respectively, in the controls. EET-B blunted the decrease of HIF-1β immunoreactivity (7.80 ± 0.69% and 6.44 ± 1.37%, respectively) and significantly reduced PHD3 immunogenic signal in ischemic tissue after reperfusion. In conclusion, EET-B provides an infarct size-limiting effect at reperfusion that is mediated by HIF-1β and downregulation of its degrading enzyme PHD3. NEW & NOTEWORTHY The present study shows that EET-B is an effective agonistic 14,15-epoxyeicosatrienoic acid analog, and its administration before reperfusion markedly reduced myocardial infarction in rats. Most importantly, we demonstrate that increased hypoxia-inducible factor-1β levels play a role in cardioprotection mediated by EET-B in reperfusion likely by mechanisms including downregulation of the hypoxia-inducible factor-1β-degrading enzyme prolyl hydroxylase domain protein 3.

Original languageEnglish (US)
Pages (from-to)H1148-H1158
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume315
Issue number5
DOIs
StatePublished - Oct 2018

Keywords

  • Epoxyeicosatrienoic acid
  • Heart
  • Hypoxia-inducible factor-1β
  • Ischemia-reperfusion
  • Prolyl hydroxylase 3

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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