Fig. 6. FXII interacts with uPAR to signal on tubular cell surface.

a, b Representative immunoblots (a loading control: β-Actin) and dot-plot summarizing results (b) for uPAR expression in kidney lysates of normoglycemic controls (C) and hyperglycemic (DM) wild type (WT) and F12^-/- mice. Dot-plot reflecting mean ± SEM of 6 mice per group; two-way ANOVA with Tukeys’s multiple comparison test. c, d Representative histogram (c) and dot-plot summarizing the results (d) of uPAR surface staining determined by flow cytometry (mean fluorescence intensity, MFI) in HKC-8 cells exposed to purified human FXII (62 nM) in the presence of Zn²⁺ (10 µM) for 6, 24, and 48 h. Dot-plot reflecting mean ± SEM of 3 independent experiments; one-way ANOVA with Tukeys’s multiple comparison test. e, f Representative images of proximity ligation assay (PLA, e) and dot-plot summarizing results (f) in PTCs exposed to normal (5 mM) or high (25 mM) glucose for 24 h. PLA signals representing FXII and uPAR interaction are immunofluorescently detected, red; DAPI nuclear counterstain, blue; phalloidin for cytoskeleton, green. Scale bars represent 20 μm. Dot-plot reflecting mean ± SEM of 3 independent experiments quantifying 30 cells from each condition with each dot representing the number of PLA signals/cell; two-tailed unpaired student’s t test. g, h Representative histological images of proximity ligation assay (g, PLA, red dots representing FXII and uPAR interaction) and dot-plot summarizing results (h) in human kidney sections of nondiabetic controls (C) or diabetic patients with DKD (DKD); DAPI nuclear counterstain (blue). Scale bars represent 20 μm. Dot-plot reflecting mean ± SEM of 5 samples per group with each dot representing the mean of PLA signals/field for one sample; two-tailed unpaired student’s t test. Source data are provided as a “Source Data” file.