Prospective isolation of mouse and human hematopoietic stem cells using PLXDC2

Numerous strategies exist to isolate hematopoietic stem cells (HSCs) using complex combinations of markers and flow cytometry. However, robust identification of HSCs using imaging techniques is substantially more challenging which has prompted the recent development of HSC reporter mice. To date, very few molecules used in these reporters have been useful for human HSC identification. Here we report that PLXDC2 is a useful marker for both mouse and human cord blood HSCs. Using a green fluorescent protein (GFP) knock-in at the Plxdc2 locus in mice (hereafter denoted as Plxdc2-GFP), we showed that Plxdc2-GFP is highly expressed in HSCs with 1 in 2.8 Plxdc2-GFP⁺CD150⁺ cells giving long-term multi-lineage reconstitution in transplantation. Moreover, we developed a novel human PLXDC2 antibody and showed that human PLXDC2⁺ HSCs have higher long-term multilineage reconstitution ability compared with PLXDC2^- HSCs in a xenograft model. This study identifies PLXDC2 as a highly relevant molecule in HSC identification.