Amplified genome editing by <i>in vivo</i> editor production

Genome editing enzymes have vast therapeutic potential. However, achieving sufficient delivery <i>in vivo</i> remains a major challenge, because editing machinery is confined to the subset of transfectable cells in a tissue. Here, we tested the possibility that genome editing could be amplified <i>in vivo</i> by programming transfected cells to produce and transfer editing enzymes in lipid vesicles to neighboring cells. Our data show that this NANoparticle-Induced Transfer of Enzyme (NANITE) strategy tripled editing efficiency in cultured cells relative to non-spreading controls. Furthermore, a single intravenous injection of the NANITE plasmid into mice induced ~3-fold higher levels of liver editing at the <i>Ttr</i> locus relative to non-spreading controls, with corresponding reductions in serum transthyretin levels. Amplifying therapeutic enzymes <i>in situ</i> offers a nonviral and non-infectious strategy to overcome low delivery efficiencies and reduce effective dose requirements.