Preparation of therapeutic exosomes using membrane proteins
The present invention relates to methods of preparing a therapeutic exosome using a protein newly-identified to be enriched on the surface of exosomes. Specifically, the present invention provides methods of using the proteins for affinity purification of exosomes. It also provides methods of localizing a therapeutic peptide on exosomes, and targeting exosomes to a specific organ, tissue or cell by using the proteins. The methods involve generation of surface-engineered exosomes that include one or more of the exosome proteins at higher density, or a variant or a fragment of the exosome protein.
1. A pharmaceutical composition comprising:
a. an exosome comprising a scaffold protein which comprises Prostaglandin F2 Receptor Negative Regulator (PTGFRN) or a functional fragment thereof, wherein the scaffold protein is present at a density that is higher than the density of the scaffold protein in a native exosome, and:
b. an excipient.
2. The pharmaceutical composition of claim 1 , wherein the scaffold protein comprises the amino acid sequence as set forth in SEQ ID NO: 1 without the PTGFRN signal peptide.
3. The pharmaceutical composition of claim 1 , wherein the scaffold protein comprises the amino acid sequence as set forth in SEQ ID NO: 33.
4. The pharmaceutical composition of claim 1 , wherein the exosome further comprises a therapeutic protein.
5. The pharmaceutical composition of claim 1 , wherein the density of the scaffold protein is 2-fold to 1000-fold higher than the density of the scaffold protein in a native exosome.
6. The pharmaceutical composition of claim 5 , wherein the exosome further comprises a targeting moiety.
7. The pharmaceutical composition of claim 6 , wherein the targeting moiety is specific to an organ, a tissue, or a cell.
8. The pharmaceutical composition of claim 1 , wherein the density of the scaffold protein is 32-fold to 400-fold higher than the density of the scaffold protein in a native exosome.
9. The pharmaceutical composition of claim 1 , wherein the density of the scaffold protein is 100-fold to 200-fold higher than the density of the scaffold protein in a native exosome.
10. The pharmaceutical composition of claim 4 , wherein the therapeutic protein is selected from the group consisting of:
(a) an antibody or an antigen-binding fragment thereof,
(b) an enzyme or a functional fragment thereof
(c) a ligand or a functional fragment thereof,
(d) a receptor or a functional fragment,
(e) an antimicrobial peptide or a functional fragment,
(f) a functional fragment of any of (a)-(e), or
(g) any combination of (a)-(f).
11. The pharmaceutical composition of claim 4 , wherein the therapeutic protein is fused to the scaffold protein.
12. The pharmaceutical composition of claim 1 , wherein the exosome further comprises atherapeutic compound.
13. The pharmaceutical composition of claim 12 , wherein the therapeutic compound is selected from the group consisting of a nucleotide, an amino acid, a lipid, a carbohydrate, a small molecule, and any combination thereof.
14. The pharmaceutical composition of claim 12 , wherein the therapeutic compound is conjugated to the scaffold protein.
15. The pharmaceutical composition of claim 1 , wherein the composition is substantially free of contaminating proteins.