Efficient Differentiation of Human Pluripotent Stem Cells to Angioblasts and Endothelial Cells Via Small Molecule Activation of Wnt Signaling

Heart disease is the leading cause of morbidity and mortality in industrialized countries. One possible treatment for heart disease involves producing heart cells in vitro and tranplanting these cells to restore the function of damaged tissue. We and others have previously described mthods to generate large numbers of heart muscle cells from human pluripotent stem cells (hPSCs), which have the potential to facilitate heart regeneration. However, the heart is not merely composed of muscle cells, but also contains vascular endothelial, smooth muscle cells, and cardiac fibroblasts. Thus, engineering heart tissue patches which contain both cardiomyocytes and support cells representing a more desirable approach for cell-based therapies to treat heart disease. Here we describe a method for the simple and efficient conversion of hPSCs to CD34+CD31+ angioblasts with bipotent differentiation potential, capable of generating smooth muscle and endothelial cells. We systematically optimized Wnt, FGF2, and VEGF signaling activity during angioblast differentiation and then illustrate that appropriate temporal activation of regulators of Wnt signaling alone, in the absence of exogenous FGF2 and VEGF signaling, is sufficient to drive multiple hPSC lines to differentiate to greater than 50% CD34+CD31+ angioblasts. These angioblasts can be further enriched to 99% purity with a single step of simple magnetic separation based on CD31 or CD34 expression. Single-cell clonal differentiation assays revealed that CD34+CD31+ angioblasts generated by Wnt pathway activation were bipotent and could differentiate to functional endothelial and smooth muscle cells.