In vivo engineering of hematopoietic stem cells by targeted lipid nanoparticles within humanized mice

An optimal delivery system for genetic medicines must target quiescent human HSCs to ensure long-term therapeutic efficacy. Here, we screened 15 lipid nanoparticles (LNPs) with different PEG-lipid structures and reported an LNP named LNPDP that demonstrated efficient delivery of reporter mRNA to human HSPCs both in ex vivo and in vivo settings, when conjugated with the anti-CD34 antibody (CD34/LNPDP).

Using CRISPR/Cas editing cargos, CD34/LNPDP achieved high editing efficiency in human HSPCs ex vivo. Subtle transcriptomic alterations were detected following LNP treatment, primarily attributed to the cellular uptake of exogenous cholesterol. Intrafemoral administration of CD34/LNPDP in humanized mice resulted in efficient editing of the erythroid-specific BCL11A enhancer within human HSPCs, which enables the sustained long-term reactivation of fetal hemoglobin (HbF) expression in erythroid cells.