Abstract 335: Inhibition of Histone Deacetylases Post Myocardial Infarction, Upregulates Wisp-1, a Novel Regulator of Cardiac Angiogenesis

Abstract

Introduction: Re-establishing vasculature after a myocardial infarction (MI) may spare cardiomyocytes from death due to lack of sufficient oxygen. WISP-1 -a secreted matricellular protein that regulates angiogenesis in certain cancers- promotes cell survival in isolated cardiomyocytes in vitro . However, the potential role WISP-1 plays post-MI, has not been evaluated. Histone deacetylase inhibition (HDACi) attenuate adverse effects of an MI in small animal models but it is unclear which genes and or targets contribute to this benefit. Our preliminary data shows that Wisp-1 is upregulated 15-fold in response to MI injury compared to sham-operated mice, but is upregulated 45-fold in mice that are subjected to an MI injury and treated with the HDAC inhibitor, Vorinostat. Therefore, we hypothesized that HDACi mediated upregulation of Wisp-1 contributes to beneficial angiogenesis, post-MI . Methods: To test this, we subjected 10-12 week old male mice to ligation of the L.A.D. coronary artery or a sham operation. Mice were injected daily with either DMSO/vehicle, or Vorinostat. Seven days post-MI, mice were euthanized and their heart tissue was assessed for the expression of Wisp-1 and microvasculature. We also assessed the impact of recombinant WISP-1, and respective lentiviral mediated upregulation and shRNA mediated suppression of WISP-1 expression on human coronary artery endothelial cells (HCAECs). Results: In vivo , HDACi mediated upregulation and expression of Wisp-1 /Wisp-1 is observed at the border zone of infarction and its expression is proximal to microvasculature. Recombinant WISP-1 protein promotes expression of pro-angiogenic genes and phenotypic characteristics in HCAECs. Lastly, lentiviral activation and shRNA-targeted suppression of endogenous WISP-1 respectively enhances and reduces endothelial cell network branching in vitro . Conclusion: Therapeutic interventions after a heart attack impact the extent of infarct injury, cell survival and overall prognosis. Our studies shown here identify a novel pro-angiogenic target, Wisp-1, that may be useful in post-MI treatment modalities.