In vivo genome editing of human haematopoietic stem cells for treatment of blood disorders using mRNA delivery.

Ex vivo autologous haematopoietic stem cell (HSC) gene therapy provides a promising treatment option for haematological disorders. However, current methods involve complex processes and chemotherapeutic conditioning, leading to limited accessibility for treatment and major side effects. Here we develop antibody-free targeted lipid nanoparticles (LNPs) for mRNA delivery to HSCs in vivo, enabling efficient base editing of the γ-globin gene (HBG1/2) promoter target in human HSCs to reactivate fetal haemoglobin in derived erythroid cells. Delivery of ABE8e/sgRNA mRNA with optimized LNPs achieves efficient in vivo base editing of HBG1/2 in transfusion-dependent β-thalassaemia (TDT) patient-derived HSCs engrafted in immunodeficient NCG-X mice, showing restored globin chain balance in erythroid cells. Our research indicates that using LNPs for genome editor delivery achieves efficient editing of endogenous genes of human HSCs. This non-viral delivery system eliminates the need for collecting or mobilizing HSCs, providing a potent and one-time treatment potential for blood disorders such as sickle cell disease and TDT.