Effect of authentic peroxynitrite and cyclic stretch on CD154-induced IL12-p40 mRNA and protein expression. (A-C) Urate (10μM, 30-minute preincubation) and methyl-β-cyclodextrine (MCD; 5μM, 30-minute preincubation) attenuate the peroxynitrite (160μM, 1 hour) mediated decrease in CD154-induced IL12-p40 mRNA (6-hour incubation) and protein (24-hour incubation) abundance in human umbilical vein endothelial cells (HUVEC) under static conditions (n = 3-5; *P < .05 vs CD154; #P < .05 vs CD154 + peroxynitrite). (D-E) Urate reverse the stretch-mediated (16 hours, 15% elongation, 0.5 Hz) decrease in CD154-stimulated IL12-p40 mRNA and protein levels (n = 3-4; *P < .05 vs CD154; #P < .05 vs CD154 + cyclic stretch). (F) Urate attenuates the peroxynitrite-mediated decrease in CD154-stimulated IL12-p40 protein abundance (24-hour incubation) in THP-1 cells (n = 3; *P < .05 vs CD154; #P < .05 vs CD154 + peroxynitrite). Specific stimulation of CD40 with mouse myeloma cells expressing human CD154 was verified (A,F) by preincubating these cells with a neutralizing anti-CD154 Ab (40 μg/mL).