The Effect of siRNA knockdown of pattern recognition receptors on the HMGB1-mediated NF-κB activation and TNF-α expression in HUVECs. Confluent HUVECs were transfected with the control siRNA (1 μg for 3 days) or siRNA (1 μg for 3 days) specific for TLR2, TLR4, and RAGE individually or in combination of 3 before incubating cells with HMGB1 (1 μg/mL for 16 hours). The activation of NF-κB (A) or the induction of TNF-α (B) in HUVECs was analyzed as described in “Methods.” **P < .01 compared with HMGB1; ^#P < .05 compared with TLR2; ^#P < .02 compared with TLR4; ⁺P < .05 compared with RAGE; and ⁺P < .02 compared with either TLR2 or TLR4.