The EPCR⁺population is enriched with LT-HSCs in culture. (A) Schematic representation of the experimental design to determine the impact of EPCR expression levels on HSPC activity in CB cultures expanded with UM171 (38 nM). (B) FACS profiles showing the percentage of EPCR subsets and their distribution in CD34⁺ and CD34⁺CD45RA^– populations after culture (mean ± SD, 5 biological replicates). (C) CFU-GEMM counts for sorted EPCR subsets after culture (mean ± SD, 3 technical replicates, 2 biological replicates); *P < .05 (Mann-Whitney U test, 1-sided). Human (Hu) CD45 engraftment (D) and lineage potential (E) assessed for each NSG recipient (identified as NSG-ID) of the indicated sorted cells after 7 days of culture; n = 3 to 20 mice per condition (each geometric shape corresponds to a biological replicate; horizontal bars indicate median values). (F) Frequency of LT-HSCs within EPCR^–, EPCR^Low, and EPCR⁺ populations. Estimated LT-HSC frequencies (red lines) and 95% confidence intervals (gray boxes) presented as 1/number of sorted cells at day 7. Significance level *P < .05 (Mann-Whitney U test, 1-sided).