Localization of microRNA-375 in perinatal rat pancreas

Abstract MicroRNA (miRNA)-375 is highly expressed in the pancreatic endocrine islets. Maintaining appropriate miR-375 levels is very important for beta cell development, function and proliferation. The aim of the current study was to investigate the regulation and localization of miR-375 in rat perinatal pancreas at embryonic day 20 (E20), postnatal day 0 (D0) and day 2 (D2). Expression levels of miR-375 were measured by in situ hybridization on fixed neonatal rat pancreas. Interestingly, while miR-375 was detectable at robust levels at all three time points, the major site of expression of miR-375 at D0 and D2 was in pancreatic exocrine cells. Our data show that miR-375 has a dynamic change of expression in pancreatic exocrine tissue during the perinatal period. Moreover, these findings indicate that pancreatic endocrine cells may not always be the major source of expression of miR-375 in pancreas. We suggest that the marked change of miR-375 levels in exocrine cells following birth could regulate processes involved in the adaptation of the exocrine pancreas to digestion of external nutrients derived from milk.