BMP2 Induces Direct Differentiation into Cardiomyocytes from Human Embryonic Stem Cells during Short-Tem Culture In Vitro

Abstract

Objective: Human embryonic stem cells (hESCs) can proliferate indefi nitely and differentiate into most of cell types in vitro. Previous studies of differentiation into cardiomyocytes from hESCs generally used embryoid body (EB) and growth factors. However, the effi ciency of reported differentiation strategy using EB was not suffi cient enough for further clinical application. Methods: We tried to develop an effi cient protocol using combination of activin A and bone morphogenetic protein-2 (BMP2) to induce direct differentiation from hESCs into cardiomyocytes. This was an attempt to develop a novel effi cient protocol. Results: Using our differentiation protocol, beating cardiomyocytes were generated at 14 days and the beating lasted for more than 3 weeks in vitro. Expression of undifferentiated state marker Oct4 was down-regulated and mesodermal marker Brachyury was expressed at early stage. Thereafter, expressions of cardiac-specifi c markers such as Nkx 2.5, cardiac troponin (cTn) I, myosin heavy chain (MHC), α-actinin and smooth muscle actin were confi rmed at 20 days. The expression of calcium channels markers such as Kv 1.4, 2.1, 4.3, HCN1, 2, 4 was detected from early stage of differentiation by RT-PCR. Conclusion: We demonstrated that differentiation from hESCs into cardiomyocytes was successfully induced by direct differentiation protocol using BMP2 during a short-term culture in vitro (SC1150 and No. 2009- 0071924).