Figure 4.

PAR-1 siRNA diminishes PAR-1 expression and inhibits leukocyte elastase (LE)-induced apoptosis in BEAS-2B cells. (A) The selective pharmacologic inhibitor of PAR-1, SCH79797, attenuates epithelial apoptosis by leukocyte elastase and thrombin. The data represent the mean ± SEM of n = 3 experiments. (B) Upper panel represents PAR-1 expression and the lower panel illustrates α-actin protein expression using with Western blot analysis. (C) PAR-1, cell surface receptor as detected by FACS analysis. Cells were incubated with a FITC-conjugated PAR-1 murine monoclonal antibody 72 h after transfection with control siRNA (iv), PAR-1A siRNA (ii), and PAR-1C siRNA (iii). Histogram (i) represents staining with FITC-conjugated isotype control murine IgG₁. Representative data each from one of five experiments are shown. (D) PAR-1 siRNA reduces leukocyte elastase–induced lung epithelial apoptosis. BEAS-2B cells were treated with leukocyte elastase 0.1 U/ml or buffer 12 h after transfection with siRNA. Values are mean ± SD; ++P < 0.01 compared with the sample of control siRNA transfection and buffer only incubation, **P < 0.01 compared with the sample of control siRNA transfection and leukocyte elastase treatment (n = 5).