Deletion of CXCR4 in cardiomyocytes exacerbates cardiac dysfunction following isoproterenol administration

Gene Ther. 2014 May;21(5):496-506. doi: 10.1038/gt.2014.23. Epub 2014 Mar 20.

Abstract

Altered alpha- and beta-adrenergic receptor signaling is associated with cardiac hypertrophy and failure. Stromal cell-derived factor-1α (SDF-1α) and its cognate receptor CXCR4 have been reported to mediate cardioprotection after injury through the mobilization of stem cells into injured tissue. However, little is known regarding whether SDF-1/CXCR4 induces acute protection following pathological hypertrophy and if so, by what molecular mechanism. We have previously reported that CXCR4 physically interacts with the beta-2 adrenergic receptor and modulates its downstream signaling. Here we have shown that CXCR4 expression prevents beta-adrenergic receptor-induced hypertrophy. Cardiac beta-adrenergic receptors were stimulated with the implantation of a subcutaneous osmotic pump administrating isoproterenol and CXCR4 expression was selectively abrogated in cardiomyocytes using Cre-loxP-mediated gene recombination. CXCR4 knockout mice showed worsened fractional shortening and ejection fraction. CXCR4 ablation increased susceptibility to isoproterenol-induced heart failure, by upregulating apoptotic markers and reducing mitochondrial function; cardiac function decreases whereas fibrosis increases. In addition, CXCR4 expression was rescued with the use of cardiotropic adeno-associated viral-9 vectors. CXCR4 gene transfer reduced cardiac apoptotic signaling, improved mitochondrial function and resulted in a recovered cardiac function. Our results represent the first evidence that SDF-1/CXCR4 signaling mediates acute cardioprotection through modulating beta-adrenergic receptor signaling in vivo.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic beta-Agonists / administration & dosage*
  • Adrenergic beta-Agonists / adverse effects
  • Animals
  • Apoptosis
  • Cardiomegaly / chemically induced
  • Cardiomegaly / genetics*
  • Cardiotonic Agents
  • Chemokine CXCL12 / genetics
  • Dependovirus / genetics
  • Fibrosis / chemically induced
  • Fibrosis / genetics
  • Gene Knockout Techniques
  • Gene Transfer Techniques
  • Genetic Vectors / genetics
  • Glycogen Synthase Kinase 3 / biosynthesis
  • Glycogen Synthase Kinase 3 beta
  • Heart Failure / chemically induced
  • Heart Failure / genetics*
  • Isoproterenol / administration & dosage*
  • Isoproterenol / adverse effects
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mitochondria / genetics
  • Mitochondria / pathology
  • Myocytes, Cardiac / cytology
  • Receptors, Adrenergic, beta / metabolism
  • Receptors, CXCR4 / biosynthesis
  • Receptors, CXCR4 / genetics*
  • Signal Transduction
  • Stroke Volume / drug effects
  • Stroke Volume / genetics

Substances

  • Adrenergic beta-Agonists
  • CXCR4 protein, mouse
  • Cardiotonic Agents
  • Chemokine CXCL12
  • Receptors, Adrenergic, beta
  • Receptors, CXCR4
  • Glycogen Synthase Kinase 3 beta
  • Glycogen Synthase Kinase 3
  • Isoproterenol