Figure 3. HBB^S-to-HBB^G base editing alleviates pathology in a mouse model of SCD.

(a) Lineage negative (Lin⁻) HSPCs from the bone marrow of Townes SCD mice (CD45.2, human HBB^S/S) were electroporated with ABE8e-NRCH and sgRNA RNP or not electroporated, then transplanted into irradiated CD45.1 C57BI/6 recipient mice. Unedited HBB^A/S HSPCs from Townes sickle-cell trait mice transplanted into irradiated CD45.1 C57BI/6 mice, and non-transplanted HBB^A/S Townes mice were used as healthy controls. (b) HBB^S-to-HBB^G editing efficiency in cells cultured 3 days after electroporation (pre-transplant) or in PBMCs collected 16 weeks post-transplant. ns, not significant by two-tailed Student’s t-test. (c) Percentage of β^G among β-like globin proteins by RP-HPLC analysis of blood. (d-g) Hematologic indices 16 weeks post-transplant. Statistical significance was assessed using one-way ANOVA, with Šidák’s multiple comparisons test to calculate p-values. Differences among edited HBB^S/S, transplanted HBB^A/S, and non-transplanted HBB^A/S mice were not significant. Bar values and error bars reflect mean±SD of n=6 mice (unedited HBB^S/S, edited HBB^S/S), n=2 mice (HBB^A/S), or n=5 mice (non-transplanted HBB^A/S). (h) Spleens were imaged from each mouse 16 weeks after transplantation with Townes mouse HSPCs. Representative images are shown.