The efficient induction of cardiomyocyte differentiation from embryonic stem (ES) cells is crucial for cardiac regenerative medicine. Although Wnts play important roles in cardiac development, complex questions remain as to when, how and what types of Wnts are involved in cardiogenesis. We found that Wnt2 was strongly up-regulated during cardiomyocyte differentiation from ES cells. Therefore, we investigated when and how Wnt2 acts in cardiogenesis during ES cell differentiation. Wnt2 was strongly expressed in the early developing murine heart. We applied this embryonic Wnt2 expression pattern to ES cell differentiation, to elucidate Wnt2 function in cardiomyocyte differentiation. Wnt2 knockdown revealed that intrinsic Wnt2 was essential for efficient cardiomyocyte differentiation from ES cells. Moreover, exogenous Wnt2 increased cardiomyocyte differentiation from ES cells. Interestingly, the effects on cardiogenesis of intrinsic Wnt2 knockdown and exogenous Wnt2 addition were temporally restricted. During cardiomyocyte differentiation from ES cells, Wnt2 didn't activate canonical Wnt pathway but utilizes JNK/AP-1 pathway which is required for cardiomyocyte differentiation from ES cells. Therefore we conclude that Wnt2 plays strong positive stage-specific role in cardiogenesis through non-canonical Wnt pathway in murine ES cells.
Bibliographical noteFunding Information:
This study was supported in part by research grants from the Ministry of Education, Science and Culture, Japan , the Program for Promotion of Fundamental Studies in Health Science of the National Institute of Biomedical Innovation, Japan , and by the Keio Gijuku Academic Development Funds . We are grateful to Hitoshi Niwa for providing the ES cell line EB3, to Andrew P McMahon for the cDNAs of mouse Wnt2 , and to Jan Kitajewski for the Wnt2 expression plasmid.
- Embryonic stem cell
- Induced pluripotent stem cells
- Mesodermal cells
- Non-canonical pathway