Enabling a robust scalable manufacturing process for therapeutic exosomes through oncogenic immortalization of human ESC-derived MSCs
1 Institute of Medical Biology, A*STAR, 8A Biomedical Grove, 138648 Singapore
2 Laboratory of Experimental Cardiology, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands
3 National University of Singapore, Graduate School for Integrative Sciences and Engineering, 28 Medical Drive, 117456 Singapore
4 Bioprocessing Technology Institute, A*STAR, 20 Biopolis Way, 138671 Singapore
5 Department of Surgery, YLL School of Medicine, NUS, 5 Lower Kent Ridge Road, 119074 Singapore
6 Interuniversity Cardiology Institute of the Netherlands, Catharijnesingel 52, 3511 GC Utrecht, the Netherlands
Journal of Translational Medicine 2011, 9:47 doi:10.1186/1479-5876-9-47Published: 25 April 2011
Exosomes or secreted bi-lipid vesicles from human ESC-derived mesenchymal stem cells (hESC-MSCs) have been shown to reduce myocardial ischemia/reperfusion injury in animal models. However, as hESC-MSCs are not infinitely expansible, large scale production of these exosomes would require replenishment of hESC-MSC through derivation from hESCs and incur recurring costs for testing and validation of each new batch. Our aim was therefore to investigate if MYC immortalization of hESC-MSC would circumvent this constraint without compromising the production of therapeutically efficacious exosomes.
The hESC-MSCs were transfected by lentivirus carrying a MYC gene. The transformed cells were analyzed for MYC transgene integration, transcript and protein levels, and surface markers, rate of cell cycling, telomerase activity, karyotype, genome-wide gene expression and differentiation potential. The exosomes were isolated by HPLC fractionation and tested in a mouse model of myocardial ischemia/reperfusion injury, and infarct sizes were further assessed by using Evans' blue dye injection and TTC staining.
MYC-transformed MSCs largely resembled the parental hESC-MSCs with major differences being reduced plastic adherence, faster growth, failure to senesce, increased MYC protein expression, and loss of in vitro adipogenic potential that technically rendered the transformed cells as non-MSCs. Unexpectedly, exosomes from MYC-transformed MSCs were able to reduce relative infarct size in a mouse model of myocardial ischemia/reperfusion injury indicating that the capacity for producing therapeutic exosomes was preserved.
Our results demonstrated that MYC transformation is a practical strategy in ensuring an infinite supply of cells for the production of exosomes in the milligram range as either therapeutic agents or delivery vehicles. In addition, the increased proliferative rate by MYC transformation reduces the time for cell production and thereby reduces production costs.