Fig 2: OM-MSCs alleviated the OGD/R-induced GA stress response in N2a cells through PEDF production. (a, b) The protein level of PEDF in N2a cells was measured by western blotting. (c, d) Apoptosis percentage was evaluated using flow cytometry analysis. (e, f) The protein expression of GOLPH3 and SPCA1 was determined using western blotting. (g) Intracellular ROS level was measured by flow cytometry analysis using an oxidation-sensitive fluorescent probe (DCFH-DA). (h) Intracellular Ca2+ concentration in N2a cells was examined by flow cytometry analysis using a Fluo-3/AM kit. (i) The representative image of GA ultramicrostructure changes by using a transmission electron microscope (scale bar = 2.0 μm). The GA was indicated by the red arrow. Data were displayed as mean ± SD based on three independent experiments. ∗p < 0.05, ∗∗p < 0.01, and ∗∗∗p < 0.001 compared with the normal group; #p < 0.05, ##p < 0.01, and ###p < 0.001 compared with the OGD/R group; &p < 0.05, &&p < 0.01, and &&&p < 0.001 compared with the OGD+OM-MSC group.

Fig 3: Characterisation of RP11 - RPE cells revealed polarity and functional defects. a Schematic of RPE differentiation timeline; b Bright-field images of iPSC-derived RPE: representative examples from at least ten independent experiments, scale bar 100 µm; c Immunostaining for basolateral markers BEST1 and Na+/K+-ATPase: representative images from three independent experiments, scale bar 50 µm; d Correct basolateral distribution of collagen IV (C-IV) and apical MERTK in unaffected control (WT3) but not RP11 RPE cells: representative images from three independent experiments, scale bar 50 µm; e, f ELISA assays for apical and basal secretion of PEDF and VEGF, respectively, in control and RP11 - RPE cells; g Trans-epithelial resistance measurements revealed a significant difference between patient and RP11 - RPE cells; h Reduced phagocytic capacity in RP11 - RPE cells. Statistical significance is calculated for MFI (mean fluorescence intensity) values. e–h Data shown as mean ± SEM, n = 3. Statistical significance of pairwise comparisons is indicated by n.s.: not significant; ***p < 0.001; ****p < 0.0001 (Student’s paired t test). b–h Data obtained from RPE at week 21 of differentiation

Fig 4: OM-MSCs promoted the phosphorylation of the PI3K/Akt/mTOR pathway via PEDF. (a, b) The ratios of p-Akt/Akt protein and p-mTOR/mTOR protein were evaluated by western blotting. OM-MSCsPEDFsiRNA: knockdown of PEDF in OM-MSCs by transfecting PEDF-specific siRNA; MSCsNCsiRNA: OM-MSCs were transfected with normal control siRNA. Data were displayed as mean ± SD based on three independent experiments. ∗∗∗p < 0.001 compared with the normal group; #p < 0.05, ##p < 0.01, and ###p < 0.001 compared with the OGD/R group; &p < 0.05, &&p < 0.01 compared with the OGD/R+OM-MSC group.

Fig 5: CD9+CD55low APCs promote adipocyte lipolysis.a Volcano plot of differentially secreted proteins in culture medium of CD9+CD55low APCs between T2D patients with obesity and lean control subjects. The increased proteins and decreased proteins are highlighted in red and blue. b The concentration of PEDF in the culture medium of CD9+CD55low APCs from lean control individuals (n = 8) and T2D patients with obesity (n = 8). c Correlation between frequency of CD9+CD55low APCs and serum FFA levels (n = 40). d–f Human primary adipocytes were isolated from lean control subjects and co-cultured with CD9+CD55low APCs from lean control individuals or T2D patients with obesity; meanwhile, neutralizing PEDF antibody (25 μg ml−1) was added in the lower chamber. Three days after co-culture, culture mediums and adipocytes were collected. d Illustration of the co-culture experiments. e,f Levels of FFA (e) and glycerol (f) in culture medium (n = 4 per group), FFA, free fatty acid. For g–m, eight-weeks old PD mice were treated with tamoxifen to deplete APC. One week later, 1×106 CD9+CD55low APCs from lean control subjects and T2D patients with obesity were transferred in situ into eWAT of receipt mice, which were subsequently challenged with HFD. Serum and eWAT were collected at the indicated time points. g Schematic of the cell transplantation experiment. h eWAT weight of mice in three groups (n = 5 per group). i Representative H&E images of eWAT in three groups. j, Quantification of adipocyte diameter (n = 5 per group). k,l Levels of FFA (k) and glycerol (l) in serum of mice at each time point (n = 5 per group). m Five days after HFD feeding, the eWAT of receipt mice was collected to harvest SVF. Flow cytometry analysis was conducted to detect transplanted human APCs by staining with anti-human PDGFRA and anti-human CD9 antibodies. Representative plots indicate transferred human APCs in the eWAT of recipient mice. Data are means ± SD. The following tests were used. a Unpaired two side Welch’s t test. b Two-tailed unpaired Student’s t test. c Spearman’s bivariate correlation test (One-tailed) were used. e, f, h, j–l One-way ANOVA followed by Tukey’s multiple comparison test. Source data are provided as a Source data file.