Fig. 1
Enhanced trapping of MT4-MMP-null peritoneal macrophages due to increased αM integrin (Itgam) levels and activity. a Representative flow cytometry dot plots and histograms of mouse peritoneal macrophages stained for CD45, Itgam, and F4/80 in basal conditions (left) and 72 h after thioglycollate (TG) injection (right). b Number of macrophages (Itgam+F4/80+) collected in the peritoneal eluate of wild-type and MT4-MMP-null mice at the indicated times after TG injection; n = 3 mice in basal and n = 12 mice at 72 h per genotype in one in basal and four in 72 h independent experiments, respectively. c Representative confocal microscopy images (left) and quantification (right) of monocytes/macrophages (Itgam+) in the peritoneal membrane 72 h after TG injection; n = 6 mice per genotype in two independent experiments; scale bar, 50 µm. d Flow cytometry analysis of Itgam cell-surface levels in TG-elicited macrophages (Itgam+F4/80+) obtained 72 h after TG injection; n = 20 mice per genotype in four independent experiments. e qPCR analysis of Itgam mRNA in TG-elicited macrophages adhered to plastic overnight; n = 6 samples per genotype in two independent experiments. f Itgam integrin affinity assessed as the number of C3-opsonized red blood cells (RBCs) bound to TG-elicited peritoneal macrophages adhered to glass; n = 6 samples per genotype from two independent experiments. g Representative fluorescence images of TG-elicited macrophages adhered to fibrinogen for 24 h and labeled for F-actin in the presence or absence of Itgam blocking antibody M1/70 or IgG isotype control (left). The histogram shows quantification of the cell area (right). Scale bar, 30 µm. n = 6 samples per genotype in two independent experiments. Data were tested by two-way ANOVA followed by Bonferroni’s post test in f, by two-tailed Student’s t-test in b, c, d, and e, and by one-way ANOVA followed by Bonferroni’s post test in g. Results are expressed as mean ± SEM. *p < 0.05, **p < 0.01, and ***p < 0.001
