Reassessing the abundance of miRNAs in the human pancreas and rodent cell lines and its implication

Abstract

miRNAs are critical for pancreas development and function. However, we found that there are discrepancies of pancreatic miRNA abundance in published datasets. To obtain a more relevant profile that is close to the true profile, we profiled small RNAs from human islets cells, acini, and four rodent pancreatic cell lines routinely used in diabetes and pancreatic research using a bias reduction protocol for small RNA sequencing. In contrast to the previous notion that miR-375-3p is the sole dominant pancreatic miRNA, we found that miR-148a-3p and miR-7-5p were equally abundant in islets. In silico studies using predicted and validated targets of these three miRNAs revealed that they possibly work in cooperation to modulate cell differentiation in endocrine and exocrine cells. Our results also suggest, compare to the well characterized miR-375, both miR-148a-3p and miR-7-5p may play more critical roles in human pancreas development and function. Moreover, according to in silico predicted targets, we found that miR-375-3p had a much broader target spectrum by targeting the coding sequence and the 5 untranslated region rather than the conventional 3 untranslated region, suggesting additional unexplored roles for miR-375-3p beyond pancreas. Our study provides a valuable resource for studying miRNAs in pancreas.