Targeting DNA-LNPs to Endothelial Cells Improves Expression Magnitude, Duration, and Specificity

. Herein, we report the first instances of extrahepatic DNA-LNP targeting. DNA-LNPs conjugated to antibodies against PECAM-1 or VCAM-1 target the endothelium of the lungs and brain/spleen, respectively. These LNPs drive robust transgene expression in their target organs, with greater magnitude and duration than untargeted LNPs. Lung specificity of PECAM-targeted transgene expression increases over two weeks, resulting in markedly higher lung-to-liver expression ratios than our previous PECAM-targeted mRNA-LNPs. Off-target liver DNA expression declines to undetectable levels but persists in the lungs, while mRNA expression uniformly decreases due to its short half-life. We further improve this expression specificity by replacing full-length antibodies with Fab fragments. Single-cell analysis reveals a key mechanism underlying the improvements in organ-specificity: target organ expression is dominated by long-lived endothelial cells, while off-target liver delivery and expression are in non-endothelial cells with shorter half-lives. Collectively, these studies demonstrate that targeted DNA-LNPs achieve high levels of organ- and cell-type-specific transgene expression and thus provide a therapeutic platform for dozens of endothelial-centric diseases.