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Cyclin-dependent kinase 2 signaling regulates myocardial ischemia/reperfusion injury

David A Liem1, Peng Zhao, Ekaterini Angelis

  • 1Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA.

Journal of Molecular and Cellular Cardiology
|August 12, 2008
PubMed

Insights

Inhibition of cyclin-dependent kinase-2 (Cdk2) reduces heart cell death and infarct size during ischemia/reperfusion (I/R) injury. The retinoblastoma gene product (Rb) plays a protective role against this cardiac injury.

Area of Science:

  • Cardiovascular Biology
  • Molecular Cardiology
  • Cell Cycle Regulation

Background:

  • Ischemia/reperfusion (I/R) injury is a significant cause of heart damage.
  • Cell cycle proteins, including cyclin-dependent kinase-2 (Cdk2) and retinoblastoma gene product (Rb), are implicated in I/R injury and apoptosis.
  • Cdk2 activation leads to Rb inactivation, promoting apoptosis in cardiac cells.

Purpose of the Study:

  • To investigate the role of Cdk2 and Rb in myocardial I/R injury.
  • To determine if inhibiting Cdk2 activity offers cardioprotection.
  • To elucidate the specific role of Rb as a target in Cdk2-mediated I/R injury.

Main Methods:

  • Inhibition of Cdk2 activity in cultured cardiac myocytes and in vivo mouse models of I/R injury.
  • Assessment of infarct size (IFS), myocyte apoptosis, TUNEL positive nuclei, and caspase-3 activity.
  • Utilizing cardiac-specific Rb-deficient mice (CRb(L/L)) to evaluate the consequences of Rb loss during I/R injury.

Main Results:

  • Blocking Cdk2 activity reduced apoptosis in cultured cardiac myocytes.
  • In vivo inhibition of Cdk2 led to a 36% reduction in IFS and decreased apoptotic myocytes.
  • Loss of Rb in CRb(L/L) mice significantly exacerbated I/R injury, with a 140% increase in IFS, 92% increase in TUNEL positive nuclei, and 36% increase in caspase-3 activity.

Conclusions:

  • Cdk2 signaling pathways are critical regulators of cardiac I/R injury.
  • Inhibition of Cdk2 demonstrates cardioprotective effects against I/R injury.
  • The retinoblastoma gene product (Rb) plays a significant protective role in the heart during I/R injury.

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