SDF-1/CXCR4 mediates acute protection of cardiac function through myocardial STAT3 signaling following global ischemia/reperfusion injury

Am J Physiol Heart Circ Physiol. 2011 Oct;301(4):H1496-505. doi: 10.1152/ajpheart.00365.2011. Epub 2011 Aug 5.

Abstract

Stromal cell-derived factor-1α (SDF-1) has been reported to mediate cardioprotection through the mobilization of stem cells into injured tissue and an increase in local angiogenesis after myocardial infarction. However, little is known regarding whether SDF-1 induces acute protection following global myocardial ischemia/reperfusion (I/R) injury and if so, by what molecular mechanism. SDF-1 binding to its cognate receptor CXCR4 has been shown to activate STAT3 in a variety of cells. STAT3 is a cardioprotective factor and may mediate SDF-1/CXCR4-induced acute protection. We hypothesized that SDF-1 would improve myocardial function through CXCR4-increased STAT3 activation following acute I/R. Isolated mouse hearts were subjected to 25-min global ischemia/40-min reperfusion and divided into groups of 1) vehicle; 2) SDF-1; 3) AMD3100, a CXCR4 inhibitor; 4) SDF-1 + AMD3100; 5) Stattic, a STAT3 inhibitor; 6) SDF-1 + Stattic; 7) cardiomyocyte-restricted ablation of STAT3 (STAT3KO); 8) STAT3KO + SDF-1; 9) Ly294002, an inhibitor of the Akt pathway; and 10) SDF-1 + Ly294002. Reagents were infused into hearts within 5 min before ischemia. SDF-1 administration significantly improved postischemic myocardial functional recovery in a dose-dependent manner. Additionally, pretreatment with SDF-1 reduced cardiac apoptotic signaling and increased myocardial STAT3 activation following acute I/R. Inhibition of the SDF-1 receptor CXCR4 neutralized these protective effects by SDF-1 in hearts subjected to I/R. Notably, inhibition of the STAT3 pathway or use of STAT3KO hearts abolished SDF-1-induced acute protection following myocardial I/R. Our results represent the first evidence that the SDF-1/CXCR4 axis upregualtes myocardial STAT3 activation and, thereby, mediates acute cardioprotection in response to global I/R.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Biotransformation / drug effects
  • Blotting, Western
  • Caspases / physiology
  • Chemokine CXCL12 / physiology*
  • Extracellular Signal-Regulated MAP Kinases / physiology
  • Heart / physiology*
  • In Vitro Techniques
  • L-Lactate Dehydrogenase / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Myocardial Reperfusion Injury / pathology*
  • Oncogene Protein v-akt / physiology
  • Receptors, CXCR4 / physiology*
  • STAT3 Transcription Factor / genetics
  • STAT3 Transcription Factor / physiology*
  • Signal Transduction / physiology

Substances

  • Chemokine CXCL12
  • Cxcl12 protein, mouse
  • Receptors, CXCR4
  • STAT3 Transcription Factor
  • Stat3 protein, mouse
  • L-Lactate Dehydrogenase
  • Oncogene Protein v-akt
  • Extracellular Signal-Regulated MAP Kinases
  • Caspases