EVs are being recognized as vectors for
drug delivery. In particular. EV loading with targeting and therapeutic agents brings along an interesting opportunity to translate EVs into a bio-mimetic selective
delivery system. Indeed. EVs constitute a physiological carrier being potentially less immunogenic than artificial delivery vehicles. The inventors now developed a novel method to control the loading of a cargo into EVs
on demand. These EVs are equipped, if necessary, with non-viral fusogen, therefore enhancing EV-cargo delivery into
acceptor cells. To acutely measure this process, they follow the fate of a
luciferase-tagged cargo. Cargo loading was enabled through a
drug-reversible inducible dimerization
system. Briefly, donor cells were transfected with plasmids encoding for
FKBP-tagged CD63, a classical membrane EV marker, and FRB-Nanoluciferase (NLuc) that is normally cytosolic. Upon addition of the dimerizing
drug. FRB-Nluc interacts with
FKBP-CD63 and is recruited into secreted EVs. This is accompanied by an enhanced delivery into
acceptor cells. This phenomenon can be further enhanced when EVs are equipped with syncitin1, a mammalian fusogenic
protein that trigger fusion between EV membrane and the
plasma membrane of
acceptor cells. Using this novel process, the inventors further demonstrated that the catalytic domain of the Diphteria
toxin (DTA), that is responsible for
protein synthesis inhibition and ultimately
cell death, can be delivered to acceptor cells via functionalized EVs. This led to
protein synthesis inhibition and death of acceptor cells. This novel method and the derived applications promise to open new
doors in precision care
medicine, especially when EVs will be equipped with antibodies raised against
cell specific antigens.