Single-cell transcriptome of early hematopoiesis guides arterial endothelial-enhanced functional T cell generation from human PSCs

Human pluripotent stem cells (hPSCs) provide a powerful platform for studying the dynamic molecular network towards hematopoiesis. To date, a comprehensive roadmap at single-cell resolution for hPSC-derived hematopoietic differentiation has not been established. Here, we performed extensive single-cell transcriptomic analyses to map fate choices and gene expression programs during hematopoietic differentiation of hPSCs and identified strategies to improve the quantity and quality of hPSC-derived hematopoietic cells. By focusing specifically on cell populations and molecular events involved in endothelial-to-hematopoietic transition (EHT), the EHT was identified accompanying by a decline in aerobic metabolism and providing hypoxia in vitro enhances arterial and hematopoietic differentiation. Furthermore, arterial endothelial cells are validated as a critical regulator of definitive hematopoietic progenitor specification. Collectively, our study provides benchmark datasets to understand the origins of human hematopoiesis and presents an advance for guiding the generation of functional hematopietic cells in vitro for clinical applications. Overall design: The study constructed the first hematopoietic landscape of hPSCs at the single-cell level and identify novel strategies for promoting definitive hematopoietic differentiation of hPSCs for applications in hematological biology.