The most exciting development in Exosome research is that of exosome engineering. Work already being carried out suggests that by their innate purpose, exosomes can be used as the ultimate “nanovehicles”, delivering custom cargos into target cells. Tools already exist to allow you to package and traffic nucleic acids, and even small molecules into target cells. miRNA cane be delivered for knock down studies, small molecules for biochemical or therapeutic studies. The possibilities are endless.
Generating Exosomes with custom cargo – Exo-Fect vs. XMIR/AXMIR
There are two different options for generating exosomes with custom RNA cargo, and the choice of which to use depends on what your experimental goals are and what materials you’re working with.
Exo-Fect is a novel nucleic acid transfer agent that enables the transfection of nucleic acids and small molecules directly into isolated exosomes in less than an hour. The Exo-Fect system can be used to deliver a wider variety of cargo to exosomes, such as plasmids, larger RNAs like mRNAs, and small molecules. The exosomes need to be either isolated or purchased first, and are then “exofected” (exosomes are “transfected”).
XMIR and AXMIR kits, allow you to simply fuse a sense (XMIR) or antisense (AXMIR) miRNA oligo to the XMIR/AXMIR RNA tag and transfect into the exosome-producing cells of your choice. For some studies, this may result in a larger supply of custom exosomes, and the XMIRXpress lentiviral system allows stable exosome packaging cell lines to be made for a constant supply of miRNA-loaded exosomes. This system is good for knocking down expression of a target in the recipient cells, or for studying other biological functions.
To summarise, the Exo-Fect system enables flexibility with cargo material and the ability to customize cargo when your exosomes are generated by difficult-to-transfect cell lines. The XMIR/AXMIR system enables generation of stable exosome packaging cell lines.
Use Exosomes as Transfection Vehicles
EV Shuttle Kits form the next generation of technology for transfection of cells that are typically resistant to many other methods (ie. Lipofectamine®). EV shuttle kits utilise exosomes for this purpose, enabling the efficient and gentle transfer of RNA and DNA into cells that previously could only be nucleofected.
Label Exosome Cargo
What happens to exosome cargo once it is delivered to a cell? You can now find out by fluorescently labelling RNA or protein in isolated exosomes, and then delivering the exosomes to target cells. With Exo-Glow, Exo-Red for RNA and Exo-Green for proteins – the fate of exosomal RNA or proteins can be tracked once they’ve been delivered to the recipient cells.
Package Proteins inside Exosomes
XPack is the protein equivalent of XMIR/AXMIR (for miRNA), and tags proteins for incorporation into exosomes. An optimised peptide sequence targets a protein to the interior exosomal membrane, allowing the fusion protein to be packaged into exosomes for secretion. Available for immediate use are pre-made XPack-GFP and XPack-Luciferase reporters for tracking exosomes. Alternatively, you can design your own exosome-targeted protein for custom exosomes.