Bone morphogenetic protein 4 induces hematopoietic stem cell development from murine hemogenic endothelial cells in culture

Hematopoietic stem cells (HSCs) develop from hemogenic endothelial cells (HECs) during mouse embryogenesis. Understanding the signaling molecules required for HSC development is crucial for the in vitro derivation of HSCs. We previously induced HSCs from embryonic HECs, isolated at embryonic day 10.5 (E10.5), in serum-free culture conditions with stem cell factor, thrombopoietin, and an endothelial feeder layer. Here, we aimed to elucidate signal requirements for inducing HSCs from earlier-stage HECs. Single-cell RNA sequencing (RNA-seq) analysis detected bone morphogenetic protein (BMP) signaling activation in E9.5 HECs. Adding BMP4 to the culture conditions led to the induction of HSCs from E9.5 HECs. Furthermore, isolating BMP4 receptor-expressing HECs from E9.5 embryos enriched progenitors with HSC-forming ability. This study identified BMP4 as an essential factor promoting the differentiation of early HECs into HSCs, opening up new possibilities for the in vitro derivation of HSCs. [Display omitted] •Single-cell RNA-seq analysis detects BMP signaling activation in early HECs•BMP4 is required for inducing transplantable HSCs from early HECs in culture•Early HECs that can form HSCs express BMP4 receptor Ogawa and colleagues reproduce the developmental process of hematopoietic stem cells (HSCs) from mouse embryo-derived immature hemogenic endothelial cells (HECs) in culture. BMP4 was newly identified as an essential factor in inducing HSC development from immature HECs. The BMP4 receptor serves as a valuable marker for isolating HSC-competent immature HECs to dissect the early steps of HSC development.