Effect of APC or PC-gla/MeizoTh on the HMGB1-mediated NF-κB activation and TNF-α expression. Confluent HUVECs were incubated with HMGB1 (1 μg/mL for 16 hours) after treating cells with APC (100nM) for 3 hours. The activation of NF-κB (A) or the induction of TNF-α (B) in HUVECs was analyzed as described in “Methods.” In the presence of Abs, cells were first preincubated with function-blocking Abs to PAR-1 or EPCR (25 μg/mL for 30 minutes) before treating cells with APC. (C-D) The same as panels A and B, except that instead of 100nM APC, 2nM MeizoTh (white bars) or 2nM PC-gla/MeizoTh (black bars) was used in the experiments. All results are shown as means ± SDs of 5 different experiments. **P < .01 compared with HMGB1.