Fig. 4

Exosomal miR-21 derived from hypoxic ADSCs activates PI3K/AKT signalling by targeting SPRY1 in the HUVECs. A Schematic representation of the putative binding sites for miR-21-5p in the SPRY1 3′-UTR. Predicted consequential pairings of the target regions and miR-21 (underlined) were based on data from TargetScan (www.targetscan.org). B Luciferase reporters containing wild-type or mutant 3′-UTR of SPRY1 genes were co-transfected with miR-21-NC or miR-21 mimics into HEK293 cells. Two days after transfection, the dual luciferase activity was measured. C–G qRT-PCR was performed to measure the mRNA level of SPRY1, PI3K, AKT VEGFA and HIF-1α in the HUVECs in different groups. H Western blot was performed to measure the level of SPRY1, PI3K, AKT VEGFA and HIF-1α in the HUVECs in different groups