Fig. 3

Exosomes derived from HK-2 cells treated with HG induced endoplasmic reticulum (ER) stress in MMCs through miR-92a-1-5p. A TEM analysis revealed ER structure of MMCs treated with NG or HG-treated HK-2 cell-derived exosomes with 10 μg for 72 h. ^* as ER structure. B qPCR was used to measure X-box binding protein 1 spliced and unspliced (XBPs-1/XBPμ-1) ratio in MMCs treated with NG or HG-treated HK-2 cell-derived exosomes for 48 h. C After treatment with NG or HG-treated HK-2 cell-derived exosomes for 48 h, activating transcription factor 6 (ATF-6), C/EBP homologous protein (CHOP), phospho-inositol-requiring transmembrane kinase/endoribonuclease 1α (IRE1α) and phospho-protein kinase RNA-like endoplasmic reticulum kinase (PERK) expression in MMCs were assessed by Western blotting. D The levels of ATF-6 in MCs of kidneys in mice and humans. The kidney sections of non-diabetic db/m mice (n = 4) and diabetic db/db mice (n = 4) at 12th week, and human donors (UTUC with normal kidney function and normal glomeruli) (n = 4) and patients with DN (n = 4) were co-stained with ATF-6 (brown) and α-SMA (green), as the marker of MCs. Arrow shows as MCs. E The Ontology analysis of cell component for potential genes targeted by miR-92a-1-5p using DAVID database and STRING database. F TEM analysis revealed ER structure of MMCs transfected with miR-92a-1-5p mimic (100 nM) or mimic control (miR-NC, 100 nM) for 24 h and then treated under NG condition for 48 h. G The ratio of XBPs-1/XBPμ-1 in MMCs transfected with miR-92a-1-5p mimic for 24 h and then treated under NG condition for 48 h was examined using qPCR. H Western blotting analysis of ATF-6, phospho-IRE1α and phospho-PERK, and CHOP expression in MMCs transfected with miR-92a-1-5p for 24 h and then treated under NG condition for 48 h. The images quantification was performed using the IHC Profiler Plugin of ImageJ Software. The bar graph represents the mean ± S.E.M. of at least three independent experiments. *p < 0.05, **p < 0.01, ***p < 0.001 by Student’s t-test