Transcriptional and protein-level profiling of engraftable human fetal liver (fl)-derived hematopoietic stem cells (HSCS)

We provide an in-depth characterization of engraftable fetal liver (FL) HSCs as these have been shown to possess superior engraftment potential compared to cord blood (CB) and bone marrow (BM) HSCs. We have single cell profiled 26,407 FL cells, of which 7,235 highly-enriched functional FL HSCs, both at the transcriptional and protein level to uncover the detailed molecular signature of engraftment potential. Following dissociation of human FL, cells were divided into either CD34+-enriched cells or CD34- flowthrough cells via magnetic bead separation. The CD34- live cell fraction was further subdivided into GYPA+ and GYPA- via fluorescence activated cell sorting (FACS). From the CD34+-enriched fraction live CD34+ cells were sorted (CD34+bulk). In a separate sample, we further enriched this population using FACS based on GPI-80 expression (GPI-80+), a marker tightly linked to engraftment potential to focus our analysis on HSCs capable of long-term engraftment. Prior to sorting, cells were stained with a panel of oligo-tagged antibodies so that the antibody-derived tags (ADTs) corresponding to the cell surface markers present on each cell would also be captured in the sequencing data.