Role of Wnt signaling in cardiac differentiation from mouse embryonic stem cells and induced pluripotent stem cells

Role of Wnt signaling in cardiac differentiation from mouse embryonic stem cells and induced pluripotent stem cells

Asako Shigeno1, Takahiro Sogo1, Tomohide Takaya2, Yoji Kojima2, Koji Hasegawa3, Teruhisa Kawamura1.

  1. Career-Path Promotion Unit for Young Life Scientists, Kyogo University, Kyoto, Japan.
  2. Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
  3. Division of Translational Research, Kyoto Medical Center, National Hospital Organization, Kyoto, Japan.

World Congress of Cardiology Scientific Sessions 2010 (Beijing, China), 2010/06/18 (Talk).

Abstract

While myocardial regeneration therapy is an important approach for end-staged heart failure, clinical application of embryonic stem (ES) cells may be hindered because of the ethical issue surrounding the manipulation of oocytes and immune rejection. Recent technologies to create induced pluripotent stem (iPS) cells from mouse and human fibroblasts overcome the problems accompanied with ES cell-based regeneration therapy. Although latest studies suggest that iPS cells have potential to differentiate into cardiac myocytes under a certain culture condition, questions still remain regarding the efficiency and uniformity among different iPS cell lines. Increasing body of developmental and stem cell studies suggests that both canonical and non-canonical Wnt signaling may play a pivotal role in cardiogenesis. Thus, we tested the effects of Wnt signaling activation on cardiac differentiation from both ES and iPS cells. When mouse ES cells were treated with one of canonical Wnt ligands, Wnt3a at an early phase of differentiation, gene expressions of early cardiac marker genes such as BrachyuryT, Flk1, and Isl1 were elevated. On the other hand, early Wnt3a stimulation increased the levels of Wnt11, Wnt5a, and Dkk1, and decreased those of Wnt3a and Tcf3, suggesting the switching of Wnt signaling activation from canonical to non-canonical one. In addition, bi-phase treatment using Wnt3a at an early phase and Wnt11 at a late phase revealed additive effects of cardiac differentiation from mouse ES cells. Finally, we examined whether this strategy can be employed to create cardiac myocytes from iPS cells. iPS cells were created by retroviral transduction of Oct4, Sox2, Klf4 with or without cMyc in mouse embryonic fibroblasts, and multiple lines were tested for cardiac differentiation protocol using hanging drop methods. Some iPS cell lines display lower efficiency of cardiac differentiation, compared with a certain ES cell line. Interestingly, early Wnt3a treatment improved the efficiency in these iPS cell lines. These findings suggest that modulation of canonical and non-canonical Wnt signaling pathways may be a powerful tool to establish the cardiac regeneration therapy using iPS cells as well as ES cells.