Kobayashi, MichihiroTarnawsky, Stefan P.Wei, HaichaoMishra, AkanshaAzevedo Portilho, NathaliaWenzel, PamelaDavis, BrianWu, JiaqianHadland, BrandonYoshimoto, Momoko2019-09-052019-09-052019-07-09Kobayashi, M., Tarnawsky, S. P., Wei, H., Mishra, A., Azevedo Portilho, N., Wenzel, P., … Yoshimoto, M. (2019). Hemogenic Endothelial Cells Can Transition to Hematopoietic Stem Cells through a B-1 Lymphocyte-Biased State during Maturation in the Mouse Embryo. Stem cell reports, 13(1), 21–30. doi:10.1016/j.stemcr.2019.05.025https://hdl.handle.net/1805/20794Precursors of hematopoietic stem cells (pre-HSCs) have been identified as intermediate precursors during the maturation process from hemogenic endothelial cells to HSCs in the aorta-gonad-mesonephros (AGM) region of the mouse embryo at embryonic day 10.5. Although pre-HSCs acquire an efficient adult-repopulating ability after ex vivo co-culture, their native hematopoietic capacity remains unknown. Here, we employed direct transplantation assays of CD45-VE-cadherin(VC)+KIT+(V+K+) cells (containing pre-HSCs) into immunodeficient neonatal mice that permit engraftment of embryonic hematopoietic precursors. We found that freshly isolated V+K+ cells exhibited significantly greater B-1 lymphocyte-biased repopulating capacity than multilineage repopulating capacity. Additionally, B cell colony-forming assays demonstrated the predominant B-1 progenitor colony-forming ability of these cells; however, increased B-2 progenitor colony-forming ability emerged after co-culture with Akt-expressing AGM endothelial cells, conditions that support pre-HSC maturation into HSCs. Our studies revealed an unexpected B-1 lymphocyte bias of the V+K+ population and acquisition of B-2 potential during commitment to the HSC fate.en-USAttribution-NonCommercial-NoDerivs 3.0 United StatesAGMB-1a cellsHematopoietic stem cells (HSCs)Hemogenic endothelial cellsMouse embryospre-HSCArticle