Fig. 4

Exosomal miR-146a directly targets Numb in β-cells. a Immunofluorescent staining for NUMB expression in pancreatic sections (scale bar 20 μm). RT-qPCR analyses of the mRNA levels of Numb in islets transfected with miR-146a mimics (b) or treated with an miR-146a inhibitor combined with bmMDEs (d). Western blotting for NUMB in INS-1 cells transfected with miR-146a mimics (c) or treated with an miR-146a inhibitor combined with bmMDEs (e), β-actin was used as the loading control. f Schematic of the sequence that miR-146a targets in the WT or mutated 3′UTR of Numb mRNA. g Luciferase activity of Numb WT or mutated 3′UTR reporter plasmids in INS-1 cells transfected with miR-146a mimics or miR-NC mimics as indicated. A GSIS assay was performed to detect insulin stimulation in islets transfected with Numb overexpression (h) or siRNA (m). RT-qPCR analyses for Pdx1, Foxo1, Ngn3, and Oct4 in islets transfected with Numb overexpression (i–l) or siRNA (n–q). Data are presented as the mean ± SEM (^∗P < 0.05; ^∗∗P < 0.01; ^***P < 0.001)