Effect of siRNA knockdown of the RAGE and P2Y₁receptors on the HMGB1- and H4-mediated cell permeability in the absence and presence of polyP-70. (A-C) Confluent endothelial cells were transfected with the control siRNA (1 µg for 3 days) or siRNA (1 µg for 3 days) specific for RAGE and P2Y₁, individually or in combination of 2 before monitoring cell permeability in response to HMGB1 (40 nM), H4 (3.5 µM), and polyP-70 (50 µM). (D-E) The same as (A-B), except that permeability in response to a low concentration of either HMGB1 (10 nM) or H4 (0.44 μM) was evaluated in the presence of a low concentration of polyP-70 (2.5 μM). (F-J) The same as (A-E), except that the effect of siRNA knockdown of RAGE and P2Y₁ on the expression of either VCAM-1 (gray bar) or E-selectin (black bar) in response to different stimuli was studied. All results are shown as mean ± standard deviation of 3 different experiments. *P < .05; **P < .01.