Fig. 7. GPR97-mediated PAR2 activation enhances neutrophil-mediated bacterial phagocytosis and killing as well as endothelial cell activation and dysfunction.

a, b Phagocytosis a and killing b of live bacteria (E. coli n = 10, S. typhimurium n = 13 for phagocytosis assay n = 11 for killing assay, and S. aureus n = 8 for phagocytosis assay n = 11 for killing assay) by neutrophils incubated without or with GPR97^E-mFc. mFc was included as a negative control. Data are means ± SEM. P value was determined by one-way ANOVA. c The expressional analyses of cell activation markers (E-selectin, ICAM-1, VCAM-1 and eNOS) of HUVECs co-cultured with neutrophils in the absence or presence of GPR97^E-mFc. mFc was included as a negative control. HUVECs treated without or with LPS were used as a negative and a positive control, respectively. n = 3 independent experiments. Data are means ± SEM and p value was determined by two-sided unpaired student’s t-test. d, e Endothelial cell permeability assays of HUVECs co-cultured with neutrophils. d Assays were done in HUVEC-neutrophil co-culture in the absence or presence of GPR97^E-mFc for 20 h at 37 °C. mFc was included as a negative control. HUVECs alone treated without or with mFc were negative control groups, while those treated with thrombin were the positive control. n = 4 independent experiments. e The HUVEC-neutrophil co-culture was treated without or with aIgGs in the absence or presence of protease inhibitors/PAR2 antagonists/blocking Abs as indicated. HUVECs alone treated without or with aIgGs were included as controls. n = 3 independent experiments. Data are means ± SEM and p value was determined by two-way ANOVA. ns, non-significant. Source data are provided in the Source Data file.