Expression And Interaction Of MiR-7a And Isl-1 In Mouse Islets

It has been proved that both microRNA-7a(miR-7a)and LIM-homeodomain transcription factor Isl-1 are important factors regulating insulin synthesis and secretion,but the functional relationship between Isl-1 and miR-7a in pancreatic islet cells is unclear.The aims of this study were thus to identify the interactions of Isl-1 and miR-7a in regulating insulin synthesis and secretion.1.ByImmunofluorescence double staining,The results presented here demonstrate that miR-7a and Isl-1 are co-expressed in mouse pancreatic islet cells.2.The further in vivo experiments show that miR-7a2 deletion upregulates Isl-1 and insulin gene expressions,enhances the glucose-stimulated insulin secretion,and these are confirmed by the in vitro experiments in NIT cells using miR-7a inhibitor and mimic.3.Further,we identified the target gene of miR-7a using dual-luciferase reporter assay,and the results demonstrate that Raf1 is a direct target gene of miR-7a,modeling MEK/ERK signaling pathway to regulate Isl1 expression,and thus influencing insulin expression and secretion.These novel findings are crucial for understanding the mechanisms of insulin secretion,and the future studies of the therapeutic strategy in medicine.