Exosomes from clonal progenitor cells

1. A method of isolating an exosome having angiogenic activity comprising:

(a) incubating a clonal endothelial progenitor cell that expresses CD31 and CD34 in a basal endothelial cell growth medium or buffer for a time sufficient to allow the clonal endothelial progenitor cell to exocytose exosomes into the growth medium or buffer;

(b) harvesting the growth medium or buffer obtained from step (a); and

(c) isolating the exosomes from the growth medium or buffer obtained from step (b).

2. The method of claim 1 , wherein the buffer is PBS.

3. The method of claim 1 , wherein the growth medium is EGM-MV2.

4. The method of claim 1 , further comprising adding a precipitating agent to the growth medium or buffer obtained from step (b).

5. The method of claim 4 , wherein the precipitating agent comprises polyethylene glycol.

6. The method of claim 1 , wherein step (c) comprises centrifuging the growth medium or buffer.

7. The method of claim 1 , wherein the time of step (a) is about 16 hours.

8. The method of claim 1 , further comprising incubating the growth medium or buffer obtained from step (b).

9. The method of claim 8 , wherein the growth medium or buffer obtained from step (b) is incubated for about 16 hours.

10. The method of claim 8 , wherein the growth medium or buffer obtained from step (b) is incubated at about 4° C.

11. The method of claim 1 , wherein the clonal endothelial progenitor cell is a human cell.

12. The method of claim 1 , wherein the clonal endothelial progenitor cell expresses PCDHB2 and/or one or more other genes listed in Table 1.

13. The method of claim 1 , wherein the clonal endothelial progenitor cell is a cell from the 30-MV2-6 cell line.

14. The method of claim 1 , wherein step (a) comprises incubating about 1,000 to about 100,000 of the clonal endothelial progenitor cell per cm 2 of a tissue culture vessel.

15. The method of claim 1 , wherein the growth medium or buffer comprises a growth factor, a cytokine, a hormone, a serum, a serum substitute, an antibiotic, a vitamin, a small molecule drug, a TGFB inhibitor, or a combination thereof.

16. The method of claim 15 , wherein the TGFB inhibitor is SB43154.

17. The method of claim 1 , further comprising enclosing the isolated exosomes obtained from step (c) within a matrix or scaffold.

18. The method of claim 1 , further comprising combining the isolated exosomes obtained from step (c) with a pharmaceutically acceptable carrier.

19. The method of claim 1 , wherein the exosome is capable of inducing angiogenesis in a iron-angiogenic cell, wherein the non-angiogenic cell is a cell that exhibits reduced tube formation relative to a HUVEC cell in complete endothelial cell growth medium.

20. The method of claim 1 , wherein the exosome comprises elevated levels of hsa-miR-155- 5 p miRNA, hsa-miR-18a-5p miRNA, hsa-miR-374a-5p miRNA, hsa-miR-126-3p miRNA, or any combination thereof, relative to that in bone-marrow-derived mesenchymal stem cell exosomes.