Wnt Activation and Reduced Cell-Cell Contact Synergistically Induce Massive Expansion of Functional Human iPSC-Derived Cardiomyocytes

Cell Stem Cell. 2020 Jul 2;27(1):50-63.e5. doi: 10.1016/j.stem.2020.06.001.

Abstract

Modulating signaling pathways including Wnt and Hippo can induce cardiomyocyte proliferation in vivo. Applying these signaling modulators to human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in vitro can expand CMs modestly (<5-fold). Here, we demonstrate massive expansion of hiPSC-CMs in vitro (i.e., 100- to 250-fold) by glycogen synthase kinase-3β (GSK-3β) inhibition using CHIR99021 and concurrent removal of cell-cell contact. We show that GSK-3β inhibition suppresses CM maturation, while contact removal prevents CMs from cell cycle exit. Remarkably, contact removal enabled 10 to 25 times greater expansion beyond GSK-3β inhibition alone. Mechanistically, persistent CM proliferation required both LEF/TCF activity and AKT phosphorylation but was independent from yes-associated protein (YAP) signaling. Engineered heart tissues from expanded hiPSC-CMs showed comparable contractility to those from unexpanded hiPSC-CMs, demonstrating uncompromised cellular functionality after expansion. In summary, we uncovered a molecular interplay that enables massive hiPSC-CM expansion for large-scale drug screening and tissue engineering applications.

Keywords: GSK3; Wnt signaling; cardiomyocytes; expansion; induced pluripotent stem cells; maturation; proliferation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Differentiation
  • Cells, Cultured
  • Glycogen Synthase Kinase 3 beta
  • Humans
  • Induced Pluripotent Stem Cells*
  • Myocytes, Cardiac

Substances

  • Glycogen Synthase Kinase 3 beta