Abstract 13507: Human Cardiac Progenitor Cells Engineered with βARK-ct Have Increased Survival and Proliferation
Rationale: Failing human hearts are characterized by activated adrenergic signaling leading to receptor desensitization and upregulated GRK2. βARK-ct, a GRK2 inhibitory peptide, rescues the failing heart by resensitization of the non-responsive β-AR system and improves cardiac function through combined GRK2 downregulation, increased cardiomyocyte survival and normalization of the neurohormonal axis. However, salutary effects of βARK-ct in the context of human cardiac progenitor cells (hCPCs) function remain unexplored.
Objective: Extend cardioprotective effects of βARK-ct to the hCPC population and understand the role played by βARK-ct in augmenting hCPC survival and proliferation. Ex vivo modification of hCPCs with βARK-ct will augment hCPC ability to survive β-AR hyperactivity following commitment to cardiac lineages in a failing heart.
Methods and Results: Human CPCs positive for the stem cell marker c-kit were isolated from patients undergoing left ventricular assist device (LVAD) implantation. hCPCs were engineered to express βARK-ct, a GRK2 inhibitory peptide fused to GFP using a lentivirus expression system. βARK-ct engineering of hCPCs increased viability, proliferation and metabolic activity. Cardiac differentiation ability of βARK-ct expressing hCPCs was increased as evidenced by mRNA levels of cardiac markers such as SMA, GATA-4, vWf, cTnT. hCPCs expressing βARK-ct demonstrated enhanced survival in response to H2O2 induced oxidative stress and was concomitant with increased AKT phosphorylation. Furthermore, enhanced survival in βARK-ct engineered hCPCs was associated with increased eNOS phosphorylation and this effect was abrogated in the presence of PI3K inhibitor LY294002.
Conclusion: Genetic engineering of human CPCs with βARK-ct enhances viability proliferation and survival. The prosurvival effect of βARK-ct engineering on hCPCs is mediated by activation of AKT/eNOS pathway.
- © 2012 by American Heart Association, Inc.