Fig. 5: Metformin requires ZEB1 expression in macrophages for its anti-inflammatory effects in psoriatic disease lesions.

a Schematic of the protocols used in the Imiquimod (IMQ) mouse model. Ten-to-twelve weeks age male mice treated with Imiquimod and either PBS, doxycycline, or lactate. b H&E staining of histological ear sections of mice either untreated and treated with Imiquimod, Lactate + Imiquimod, or Doxycycline + Imiquimod. Scale bar, 50 μm. c Quantification of the epidermal ear thickness assessed in four pictures from at least four mice per condition as in (b) (n = 3,5,4,4 mice for each condition). Quantification of the ear thickness of four mice per condition. d Lactate levels in the supernatant of peritoneal macrophages from wild-type mice left untreated or treated with PBS + Imiquimod, Doxycycline + Imiquimod, or Lactate + Imiquimod (n = 3,4,3,4). e Western blot for ZEB1, MT-CO1, TOMM20 and GAPDH in peritoneal wild-type macrophages treated as in (b). f Representative pictures from three independent experiments of Zeb1^WT and Zeb1^∆M mice after 7 days of treatment with PBS, Metformin, Imiquimod or Metformin + Imiquimod. g As in (f), but ear sections were counterstained for H&E. Scale bar: 50 μm. h As in (f), epidermal ear thickness in four mice per genotype and condition in three independent experiments was quantified by ImageJ. Four separate areas in two pictures were quantified for each mouse ear (n = 4). I CD68 and ZEB1 staining along with DAPI in the skin samples from healthy donors and psoriatic patients as well as synovial membrane samples from osteoarthritis and PsA patients. Representative captions of at least two independent experiments. Scale bar: 25 μm. j MFI quantification and representative FACS plots for MTG staining in CD14+ PBMCs from six PsA patients relative to the MTG’s MFI of six healthy controls (n = 6). k As in (j), but CH₂-DCFDA staining in CD14⁺ PBMCs from four healthy donors and four PsA patients (n = 4). Graph bars in Fig. 4 represent mean values +/− SEM with two-tailed unpaired Mann–Whitney test. p ≤ 0.001 (***), p ≤ 0.01 (**) or p ≤ 0.05 (*) levels, or non-significant (ns) for values of p > 0.05. Numerical values had been added for 0.05 < p < 0.075. Raw data along p values for statistical analyses are included in the Source Data file.