Exosome-Mediated Differentiation of Mouse Embryonic Fibroblasts and Exocrine Cells into β-Like Cells and the Identification of Key miRNAs for Differentiation.

Diabetes is a concerning health malady worldwide. Islet or pancreas transplantation is the only long-term treatment available; however, the scarcity of transplantable tissues hampers this approach. Therefore, new cell sources and differentiation approaches are required. Apart from the genetic- and small molecule-based approaches, exosomes could induce cellular differentiation by means of their cargo, including miRNA. We developed a chemical-based protocol to differentiate mouse embryonic fibroblasts (MEFs) into β-like cells and employed mouse insulinoma (MIN6)-derived exosomes in the presence or absence of specific small molecules to encourage their differentiation into β-like cells. The differentiated β-like cells were functional and expressed pancreatic genes such as Pdx1, Nkx6.1, and insulin 1 and 2. We found that the exosome plus small molecule combination differentiated the MEFs most efficiently. Using miRNA-sequencing, we identified miR-127 and miR-709, and found that individually and in combination, the miRNAs differentiated MEFs into β-like cells similar to the exosome treatment. We also confirmed that exocrine cells can be differentiated into β-like cells by exosomes and the exosome-identified miRNAs. A new differentiation approach based on the use of exosome-identified miRNAs could help people afflicted with diabetes.