Fig. 5: CD9⁺CD55^low APCs promote adipocyte lipolysis.

a Volcano plot of differentially secreted proteins in culture medium of CD9⁺CD55^low 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⁺CD55^low APCs from lean control individuals (n = 8) and T2D patients with obesity (n = 8). c Correlation between frequency of CD9⁺CD55^low APCs and serum FFA levels (n = 40). d–f Human primary adipocytes were isolated from lean control subjects and co-cultured with CD9⁺CD55^low 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⁺CD55^low 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.