Abstract 14756: The Aging-Regulated Protein PNUTS Is Essential for Myocardial and Endothelial Cell Survival in vivo
Introduction: Phosphatase 1 Nuclear Targeting Subunit (PNUTS, PPP1R10) is a nuclear protein described to act as a binding platform for the PP1 phosphatase complex. PNUTS has recently found to be implicated in cell cycle, cell proliferation in cancer cells and protection against DNA damage response and apoptosis in cardiomyocytes. PNUTS expression is markedly repressed in the heart during aging.
Hypothesis: Our objective is to elucidate the potential role of PNUTS in the endothelium and myocardium and determine the mechanism by which PNUTS regulates cardiac homeostasis and endothelial cell function.
Methods: Therefore, we generated constitutive and conditional PNUTS-deficient mice by crossing PNUTSflox/flox with the cardiac deletor line Myh6-Cre and the endothelial deletor Cdh5-CreERT2 and analyze their phenotypes.
Results: The constitutive deletion of PNUTS was found to be embryonically lethal, as no PNUTS-/- mice or embryos were born. Cardiac-specific Myh6-Cre PNUTSflox/flox led to loss of PNUTS since first day of birth, which caused cardiac dilation, apoptosis and perinatal lethality. The inducible endothelial-specific Cdh5-CreERT2 PNUTSflox/flox were treated with tamoxifen in the adulthood, leading to PNUTS deletion. Two weeks later, these mice presented signs of distress, as shivering, difficulty to breath and erected fur, followed by death. Upon necropsy, the animals presented peritoneal ascites and more fragile aortas than WT mice. Sprouting assays in aortic rings showed a dramatic decrease of the angiogenic capability of endothelial cells in knock out compared to WT mice. Histology revealed pulmonary edema and renal casts along with glomerulosclerotic-like renal cortex, indicative of vascular leakage in multiple organs.
Conclusions: This work suggests that PNUTS is essential for cardiac and endothelial cell survival. Ongoing work aims at testing the hypothesis that loss of PNUTS induces apoptosis in endothelial cells, leading to renal and respiratory failure and eventually death. Also, we plan to identify the mechanism by which PNUTS causes lethality in Myh6-Cre PNUTSflox/flox pups.
Author Disclosures: N. Lozano-Vidal: None. D. Berghäuser: None. M. Muhly-Reinholz: None. S. Dimmeler: None. R.A. Boon: None.
- © 2016 by American Heart Association, Inc.