Ultrasound-mediated gene delivery specifically targets liver sinusoidal endothelial cells for sustained FVIII expression in hemophilia A mice

Abstract

The ability to target the native production site of factor VIII (FVIII)— liver sinusoidal endothelial cells (LSECs)— can improve the outcome of hemophilia A (HA) gene therapy. By testing a matrix of ultrasound-mediated gene delivery (UMGD) parameters for delivering a GFP plasmid into the livers of HA mice, we were able to define specific conditions for targeted gene delivery to different cell types in the liver. Subsequently, two conditions were selected for experiments to treat HA mice via UMGD of an endothelial-specific human FVIII plasmid: low energy (LE; 50 W/cm2, 150μs PD) to predominantly target endothelial cells or high energy (HE; 110 W/cm2, 150 μs PD) to predominantly target hepatocytes. Both groups of UMGD-treated mice achieved persistent FVIII activity levels of ∼10% over 84 days post-treatment, however, half of the HE-treated mice developed low-titer inhibitors, while none of the LE mice did. Plasma transaminase levels and histological liver examinations revealed minimal transient liver damage that was lower in the LE group compared to the HE group. These results indicate that UMGD can safely target LSECs with a lower energy condition to achieve persistent FVIII gene expression. It demonstrates that this novel technology is highly promising for therapeutic correction of HA.