c-Jun N-terminal kinase 1 is deleterious to the function and survival of murine pancreatic islets

Inhibition of c-jun N-terminal kinase (JNK) favours pancreatic islet function and survival. Since two JNK isoforms are present in the pancreas (JNK1 and JNK2), we addressed their specific roles in experimental islet transplantation. C57BL/6J (wild-type [WT]), Jnk1 (also known as Mapk8)−/− and Jnk2 (also known as Mapk9)−/− mice were used as donor/recipients in a syngeneic islet transplantation model. Islet cell composition, function, viability, production of cytokines and of vascular endothelial growth factor (VEGF) were also studied in vitro. Jnk1 −/− islets secreted more insulin in response to glucose and were more resistant to cytokine-induced cell death compared with WT and Jnk2 −/− islets (p