Suppression of Epithelial to Mesenchymal Transitioning (EMT) Enhances Ex Vivo Reprogramming of Human Exocrine Pancreatic Tissue towards Functional Insulin Producing β-Like Cells*
Due to the lack of tissue available for islet transplantation, new sources of β-cells have been sought for the treatment of type 1 diabetes. The aim of this study was to determine whether the human exocrid fraction from the islet isolation procedure could be reprogrammed to provide additional islet tissue for transplantation. The exocrine enriched cells rapidly dedifferentiated in culture and grew as a mesenchymal monolayer. Genetic lineage tracing confirmed that these mesenchymal cells arose in part through a process of epithelial to mesenchymal transitioning (EMT). A protocol was developed whereby transduction of these mesenchymal cells with adenoviruses containing Pdx1, Ngn3, MafA and Pax4 generated a population of cells that were enriched in glucagon-secreting α-like cells. Transdifferentiation or reprogramming towards insulin secreting β-cells was enhanced, however, when using unpassaged cells in combination with inhibition of EMT by inclusion of ROCK and TGF-β1 inhibitors. Resultant cells were able to secrete insulin in response to glucose and on transplantation, to normalise blood glucose levels in streptozotocin diabetic NOD/Scid mice. In conclusion, reprogramming of human exocrine enriched tissue can best be achieved using fresh material under conditions whereby EMT is inhibited. .rather than allowing the culture to expand as a mesenchymal monolayer.
- Received September 12, 2012.
- Accepted April 13, 2013.
- © 2013 by the American Diabetes Association.
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