Cooperative Effect of Erythropoietin and TGF-β Inhibition on Erythroid Development in Human Pluripotent Stem Cells.

Patient-specific human induced-pluripotent stem cells (hiPSCs) represent important cell sources to treat patients with acquired blood disorders. To realize the therapeutic potential of hiPSCs, it is crucial to understand signals that direct hiPSC differentiation to a hematopoietic lineage fate. Our previous study demonstrated that CD34(+)CD31(+) cells derived from human pluripotent stem cells (hPSCs) contain hemato-endothelial progenitors (HEPs) that give rise to hematopoietic cells and endothelial cells. Here, we established a serum-free and feeder-free system to induce the differentiation of hPSC-derived CD34(+)CD31(+) progenitor cells to erythroid cells. We show that extracellular matrix (ECM) proteins promote the differentiation of CD34(+)CD31(+) progenitor cells into CD235a(+) erythroid cells through CD41(+)CD235a(+) megakaryocyte-erythroid progenitors (MEP). Erythropoietin (EPO) is a predominant factor for CD34(+)CD31(+) progenitor differentiation to erythroid cells, whereas transforming growth factor beta (TGF-β) inhibits the development of CD34(+)CD31(+) progenitor cells. Apoptosis of progenitor cells is induced by TGF-β in early erythroid differentiation. Suppression of TGF-β signaling by SB431542 at early stage of CD34(+)CD31(+) progenitor differentiation induces the erythroid cell generation. Together, these findings suggest that TGF-β suppression and EPO stimulation promote erythropoiesis of CD34(+)CD31(+) progenitor cells derived from hPSCs.