Akt activation as treatment for dilated cardiomyopathy

San Diego State University, San Diego CA

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Abstract

DESCRIPTION (the applicant's description verbatim): Primary degenerative changes in the failing heart include remodeling associated with loss of structural organization and cardiomyocyte apoptosis. Optimal treatment strategies must approach the long term goal of a molecular approach that promotes myocardial integrity and inhibits apoptosis to prevent ventricular dilation. Myocardial pathogenesis is inhibited by activation of Akt kinase, although the potential therapeutic effect of Akt activation has never been examined in the context of dilated cardiomyopathy. Recent results have demonstrated nuclear translocation of activated Akt correlates with prevention of dilation in mouse transgenic models of cardiomyopathy. The hypothesis of this proposal is that nuclear translocation of activated Akt inhibits the initiation and progression of dilation and heart failure. Insulin-like growth factor-1 (IGF-1) or the cellular oncogene Tcl-1 initiate nuclear translocation of Akt. In addition, we have discovered similar Akt activation by genistein, a phytoestrogen compound found in soy-based dietary products that exhibits estrogen agonist properties. Innovative approaches to be used involve mice that are genetically engineered or pharmacologically treated to activate Akt, with concurrent experiments to demonstrate beneficial effects of Akt activation in rescuing a transgenic mouse model of dilated cardiomyopathy. The specific aims are: 1) to reproducibly and precisely induce Akt activation by IGF-1, genistein treatment, and Tcl-l expression; 2) to prevent pathologic and degenerative changes by activation of Akt; 3) to show that beneficial effects of Akt activation are dependent upon induction of phosphoinositide 3-kinase. Biochemical, molecular, and confocal microscopic approaches used in combination will demonstrate the efficacy of Akt activation by the various inductive stimuli as well as the impact of the different treatments upon the pathogenesis of dilation. The significance of the study is the identification and characterization of a therapeutic pathway for treatment of heart failure, along with new approaches for the activation of Akt in the heart. This study will demonstrate the relationship between Akt activation and inhibition of cardiomyopathy, providing novel directions for therapeutic treatment to induce Akt translocation and mitigate heart failure.