AAV6-mediated Cardiac-specific Overexpression of Ribonucleotide Reductase Enhances Myocardial Contractility

Mol Ther. 2016 Feb;24(2):240-250. doi: 10.1038/mt.2015.176. Epub 2015 Sep 21.


Impaired systolic function, resulting from acute injury or congenital defects, leads to cardiac complications and heart failure. Current therapies slow disease progression but do not rescue cardiac function. We previously reported that elevating the cellular 2 deoxy-ATP (dATP) pool in transgenic mice via increased expression of ribonucleotide reductase (RNR), the enzyme that catalyzes deoxy-nucleotide production, increases myosin-actin interaction and enhances cardiac muscle contractility. For the current studies, we initially injected wild-type mice retro-orbitally with a mixture of adeno-associated virus serotype-6 (rAAV6) containing a miniaturized cardiac-specific regulatory cassette (cTnT(455)) composed of enhancer and promotor portions of the human cardiac troponin T gene (TNNT2) ligated to rat cDNAs encoding either the Rrm1 or Rrm2 subunit. Subsequent studies optimized the system by creating a tandem human RRM1-RRM2 cDNA with a P2A self-cleaving peptide site between the subunits. Both rat and human Rrm1/Rrm2 cDNAs resulted in RNR enzyme overexpression exclusively in the heart and led to a significant elevation of left ventricular (LV) function in normal mice and infarcted rats, measured by echocardiography or isolated heart perfusions, without adverse cardiac remodeling. Our study suggests that increasing RNR levels via rAAV-mediated cardiac-specific expression provide a novel gene therapy approach to potentially enhance cardiac systolic function in animal models and patients with heart failure.

Publication types

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

MeSH terms

  • Animals
  • Dependovirus / genetics*
  • Disease Models, Animal
  • Genetic Therapy
  • Genetic Vectors / administration & dosage
  • Heart Ventricles / physiopathology
  • Humans
  • Mice
  • Myocardial Contraction*
  • Myocardial Infarction / physiopathology
  • Myocardial Infarction / therapy*
  • Organ Specificity
  • Rats
  • Ribonucleoside Diphosphate Reductase / genetics
  • Ribonucleotide Reductases / genetics*
  • Troponin T / genetics*


  • TNNT2 protein, human
  • Troponin T
  • Ribonucleotide Reductases
  • ribonucleotide reductase M2
  • Ribonucleoside Diphosphate Reductase