IN VITRO REPROGRAMMING OF MURINE GALL BLADDER CELLS TOWARDS THE BETA CELL FATE

Diabetes mellitus type I is characterized by the loss of insulin‐secreting β‐cells in pancreatic islets. One suitable cell therapy approach would involve an autologous source of cells that could be expanded and reprogrammed in vitro to β‐cells, which could then be transplanted back to the patient without the need of long‐term immune suppression. We hypothesized that gall bladder cells (GBCs) could fulfill these requirements, as removal of the human gall bladder is a minimally invasive surgery. Additionally, the extrahepatobiliary system and ventral pancreas share a common development origin, and therefore we reasoned that these cells would be more readily reprogrammable to β‐cells. To attempt to reprogram GBCs to a β‐cell fate, we used the transcription factors Neurog3, Pdx1 and MafA. Reprogramming to the pancreatic fate was dependant on expression of Neurog3 as the combination of Pdx1 and MafA was insufficient to induce significant expression of β‐cell‐specific genes. In both primary and passaged cultures, robust expression of pancreatic endocrine genes was detected in reprogrammed GBCs compared to controls. Importantly, the passaged GBCs expressed similar mRNA levels of pancreatic‐specific genes as the primary cultures, indicating these cells can first be expanded to large numbers prior to the reprogramming steps in order to generate a large number of β‐like cells for transplantation.