Generation of insulin-secreting cells from mouse gallbladder stem cells by small molecules in vitro

BackgroundStem cell-derived pancreatic beta -like cells hold great promise for treating diabetes. Gallbladder belongs to the extrahepatic bile duct system and possesses stem-like cells. These stem cells could be expanded in vitro and have the potential of differentiating into hepatocytes, cholangiocytes, or pancreatic cells. As the gallbladder is highly available, gallbladder stem cells provide a new cell source of pancreatic beta -like cells. In this study, we aimed to investigate an approach for the generation of pancreatic beta -like cells from gallbladder stem cells (GSCs) without genetic modification.MethodsA CK19Cre(ERT);Rosa26R-GFP mouse was used to isolate CK19(+) cells, which represented EpCAM(+) stem cells in the gallbladder. They were cultured in the modified Kubota's medium for expansion and further analyzed. Then, we developed a strategy to screen a combination of small molecules that can generate insulin-secreting cells from gallbladder stem cells. These cells were identified with markers of pancreatic cells. Finally, they were seeded into the cellulosic sponge and transplanted to the diabetic mice for functional examination in vivo.ResultsGallbladder stem cells could be expanded for more than 15 passages. They expressed typical hepatic stem cell markers including CK19, EpCAM, Sox9, and albumin. By screening method, we found that adding Noggin, FR180204, and cyclopamine could efficiently induce gallbladder stem cells differentiating into insulin-secreting cells. These cells expressed Pdx1, Nkx6.1, and insulin but were negative for Gcg. After transplantation with the cellulosic sponge, they could ameliorate hyperglycemia in the diabetic mice.ConclusionThis study provides a new approach which can generate insulin-secreting cells from the gallbladder without genetic modification. This offers an option for beta cell therapy in treating type 1 diabetes.