Abstract 20270: Apelin Enhances Cardiac Differentiation of Human Embryonic Stem Cells
Introduction: Human embryonic stem cells (hESC) have demonstrated the potential to restore the injured myocardium. Recent protocols aimed at cardiac differentiation of hESC, however, have not achieved high efficiency. The objective of our study is to establish a robust cardiac differentiation protocol. Apelin is a novel exogenous protein which serves as a critical gradient for migration of mesodermal cells fated to contribute to the myocardial lineage during embryonic development. We examined the effects of apelin on the cardiac differentiation efficiency of hESC. We hypothesized that a temporally specific exposure of apelin along with known cardiac differentiation factors will facilitate differentiation.
Methods: hESC (H7 line, Wicell) was used to form embryoid bodies (EBs), and exposed to the following factors: 1) different dosage of apelin 50, 100 or 500 nM for 14 days, 2) BMP4 10 ng/ml, activin-A 3 ng/ml, and bFGF 5 ng/ml for 5 days followed by DKK1 150 ng/ml and VEGF 10 ng/ml for 9 days, and 3) combined protocol: apelin 100 nM plus the differentiation factors in #2. End-point analyses included cardiac-specific gene expression (n=3) and the percentage of contractile EBs (n=3, 17 EBs each).
Results: EBs stayed viable and structural integrity was maintained in the presence of apelin (Fig. A). The 500 and 100 nM apelin demonstrated higher percentage of contractile EBs compared to 50nM (19±8%, 12±0% vs. 8±7%, day 21, p<0.05) (Fig. B). The combined protocol with apelin, BMP4 and activin-A resulted in the highest percentage of contracting EBs in all groups (39±9% vs. 8±7%∼19±8%, day 21, p<0.05) (Fig. B). In addition, the combined protocol increased expression of cardiac-specific genes troponinT, atrial natriuretic peptide and myosin heavy-chain.
Conclusions: Apelin showed synergistic benefits on the hESC cardiac differentiation when combined with the known differentiation factors. Increased cardiac-specific gene expression and contractile properties were detected.
- © 2010 by American Heart Association, Inc.