Gaucher disease type 1 is a lysosomal storage disorder caused by GBA1 mutations that reduce glucocerebrosidase activity, leading to glycolipid buildup, particularly in macrophages. To develop a curative approach, we established a high-efficiency genome editing platform for human and murine hematopoietic stem-progenitor cells using CRISPR/Cas9, recombinant adeno-associated virus serotype 6. To enhance homology-directed DNA repair while minimizing genotoxicity, we incorporated a new 53BP1 inhibitor, a ubiquitin variant that promotes DNA end resection and significantly increases editing efficiency. This enabled precise insertion of a human GBA1 transgene-driven by a macrophage-specific promoter-into the mouse Rosa26 and human CCR5 safe-harbor loci. To assess efficacy, we established a rapidly progressive Gaucher disease mouse model by inducing hematopoietic-specific Gba1 deletion in a D427V background. Transplantation of edited cells corrected hematologic and visceral abnormalities, normalized lipid storage, and was effective under myeloablative and reduced-intensity busulfan conditioning. Notably, therapeutic benefit was achieved with only ~ 3% edited allele engraftment. These findings offer strong proof-of-concept for ex vivo genome editing as a mutation-agnostic, potentially curative strategy for Gaucher disease and support its clinical advancement.
Keywords: CRISPR; Gaucher; busulfan; genome editing; hematopoietic; irradiation; transplantation.