Engineered Exosomes for the Delivery of Bioactive Cargo Using Transmembrane VSV-G

Vesicular stomatitis virus glycoprotein (VSVG) can both load protein cargo onto exosomes and increase their delivery ability via a pseudotyping mechanism. By fusing a set of fluorescent and luminescent reporters with VSVG, we show the successful targeting and incorporation of VSVG fusions into exosomes by gene transfection and fluorescence tracking. VSVG pseudotyping of exosomes does not affect the size or distributions of the exosomes, and both the full-length VSVG and the VSVG without the ectodomain integrate into the exosomal membrane, suggesting that the ectodomain is not required for protein loading. Finally, exosomes pseudotyped with full-length VSVG are internalized by multiple-recipient cell types to a greater degree compared to exosomes loaded with VSVG without the ectodomain, confirming a role of the ectodomain in cell tropism. This invention provides a new genetically encoded pseudotyping platform to load and enhance the intracellular delivery of therapeutic proteins via exosome-based vehicles to target cells.