Abstract

Overcoming Barriers to Therapeutic Exosome Production using Highly Scalable and Pure Embryonic Progenitor Cell Lines

David Larocca, Vice President Research and Development, ReCyte Therapeutics

Stem cell derived exosomes have shown promise in animal models as an alternative to stem cells for a wide range of regenerative medicine applications including ischemia, myocardial infarct, stroke, atherosclerosis, and wound healing.  However, production of therapeutic exosomes for clinical use will require scalable, stable and relatively pure production cell lines.  Commonly used adult stem cells such as MSCs typically suffer from poor proliferative capacity, donor variability, and population heterogeneity. These limitations may present a formidable barrier to translation of early preclinical studies to the clinic.  To address the limitations of stem cell purity and scalability, we derived hundreds of clonally pure and highly scalable human embryonic progenitor cell lines from pluripotent stem cells. We are currently investigating their potential as a scalable source of therapeutic exosomes.  Using angiogenic exosomes as a case-study, we identified 6 scalable embryonic progenitor cell lines with angiogenic activity in a HUVEC tube forming assay including endothelial, pericyte and smooth muscle cell lines.  The embryonic endothelial cell line, 30-MV2-6, expanded to over 75 population doublings (pd) compared to 16pd for adult bone-marrow MSCs.  Moreover, 30-MV2-6 exosomes had >50-fold higher levels of the angiogenic miR-126 and 6-fold higher angiogenic potency than MSC exosomes. The 30-MV2-6 exosome production was stable to at least 50pd and the potential to scale on a hollow fiber bioreactor was demonstrated. We have identified a variety of distinct cell types including endothelial, smooth muscle, cartilage, bone, fat and pericyte cell lines in our library of over 250 progenitor cell lines. Our data indicates the potential of this library to provide a richly diverse source of exosome production lines that can be mined for variety of therapeutic exosomes.