Improved engraftment of genome-edited human HSPCs in TBI- and busulfan-conditioned mice
(A) Schematic depicting the AAV6 vector genome used for HDR, the experimental design, and timeline. (B) Human cell engraftment measured by human CD45 and HLA double-positive cells and presented as the percentage of total CD45 cells in the bone marrow, peripheral blood, and spleen of NSG-MPSI mice 20 weeks post-transplantation. Each dot/square represents a mouse. Three different human HSPCs donors were transplanted into n = 14 mice for total body irradiation (TBI) and n = 12 for busulfan (BU); two-tailed Mann-Whitney test. (C) Percentage of indels in human cells that did not undergo HDR engrafted in the bone marrow of primary recipients. Dashed line represents the average of indels found in the transplanted cells. (D) Fraction of edited alleles in human cells engrafted in the bone marrow of primary recipient mice. Dashed line represents the fraction of edited alleles in the transplanted HSPC population (input) as measured by ddPCR; two-tailed unpaired t test. (E) Fraction of edited alleles in the bone marrow of secondary recipient mice, after 36 weeks in vivo (20 weeks in primary and 16 weeks in secondary recipient mice), measured by ddPCR. Each dot represents a mouse (TBI, n = 5; BU, n = 4); two-tailed unpaired t test. (F and G) Percentage of edited alleles in the input HSPC population and after transplant in primary and secondary recipient mice conditioned with BU or TBI. Each dot represents a mouse, and each shade of pink or yellow represents a different human cell donor. Lines link recipients of cells with their respective donors. Input: independent donor HSPCs before transplantation (n = 3). Primary: human cells in the bone marrow after 20 weeks in vivo (TBI, n = 13; BU, n = 12). Secondary: edited cells in the bone marrow of serially transplanted recipient mice, 36 weeks total in vivo (TBI, n = 5; BU, n = 4). All data are shown as median. (F) Ordinary one-way ANOVA with post-hoc Tukey. (G) Kruskal-Wallis with Dunn’s post-hoc test. ns, not significant.