Abstract 17773: Peptide Inhibition of PTEN Increases Mouse Survival after Sudden Cardiac Arrest
Introduction: We recently reported that TAT fusion proteins designed to activate versus inhibit the Akt related phosphatase PTEN in heart cells respectively worsen or significantly improve ischemia/reperfusion injury and contractile functional recovery. We therefore designed a short 20 amino acid peptide PTEN inhibitor, TAT-PTEN9c, for rapid tissue delivery and tissue protection after mouse sudden cardiac arrest (SCA). TAT-PTEN9c contains a TAT protein transduction domain fused to the PTEN C-terminal 9 amino acids of the PDZ-domain binding motif. We hypothesized that TAT-PTEN9c blocks PTEN membrane localization and activation, with corresponding tissue Akt activation and improved SCA survival.
Methods: Mouse cardiomyocytes were isolated from 1-3 day old mouse pups. Western blot was used to determine the efficacy of TAT-PTEN9c for enhancing Akt phosphorylation in mouse cardiomyocytes exposed to oxidant (H2O2) stress. C57BL6 mice were subjected to an established potassium-induced 8 min SCA protocol. MAP, ETCO2, body temperature and ECG were recorded until 4 h after successful cardiopulmonary resuscitation (CPR). TAT-PTEN9c (7.8 mg/kg) was given intravenously (IV) immediately after CPR (n=10) and a 2nd dose in an additional 5 mice was given at 60 min. IV administration of TAT-GFP was used to measure the kinetics of heart and brain tissue TAT protein delivery.
Results: The designed TAT-PTEN9c peptide significantly enhanced Akt activation in neonatal mouse cardiomyoctes in a concentration-dependent manner. 30 mice with successful CPR were randomly assigned to receive either saline or TAT-PTEN9c. Survival (versus cardiovascular collapse and death) was significantly increased in TAT-PTEN9c treated group compared with that of saline control at 2 h (14/15, 93% vs. 9/15, 60%, P < 0.05) and at 4 h (10/15, 67% vs. 6/15, 40%, P < 0.05) after CPR. Western blot and immunohistochemistry showed that TAT protein transduction in heart and brain was diffuse and occurred within 5 min after IV administration.
Conclusion: TAT-PTEN9c can be used after CPR in a mouse SCA model to rapidly enhance Akt activation in critical organs and prevent early cardiovascular collapse and death.
Author Disclosures: X. Zhu: None. H. Wang: None. Y. Wang: None. J. Li: None. A.R. Leff: None. T.L. Vanden Hoek: None.
- © 2014 by American Heart Association, Inc.