MicroRNA-19b downregulates insulin 1 through targeting transcription factor NeuroD1

MiR-17-92 cluster miRNAs are disclosed to contribute to the development of multiple organs and tumorigenesis, but their roles in pancreas development remains unclear. In this study, we found that miR-19b, a member of miR-17-92, was highly expressed in the pancreatic progenitor cells, and miR-19b could target the 3′ UTR of NeuroD1 mRNA to decrease its protein and mRNA levels. Functional analysis showed that miR-19b exerted little effect on the proliferation of pancreatic progenitors, whereas it inhibited the expression of insulin 1, but not insulin 2 in MIN6 cells. These results suggest that miR-19b can downregulate insulin 1 expression through targeting transcription factor NeuroD1, and thus regulate the differentiation and function of β-cells.

► Little is known about which miRNAs regulate the proliferation or differentiation of pancreatic progenitor cells. ► We found that miR-19b, a member of miR-17-92, was highly expressed in the pancreatic progenitor cells. ► MiR-19b could target 3′ UTR of NeuroD1 mRNA to decrease its protein and mRNA levels. ► MiR-19b also inhibited insulin 1 expression in pancreatic β-cell due to the reducing of NeuroD1. ► Our results indicate that miR-19b is involved in regulation of β-cell differentiation and function.