Transcription factor DNA-binding assays confirm that CD40-dependent EC activation by Jurkat D1.1 (CD154⁺) T cells is coordinated through NF-κB, AP-1, and other MAPK-regulated activities. Nuclear extracts from HUVECs transfected with siRNA-2 (▭) or msiRNA-2 (▬) and stimulated with Jurkat D1.1 for 4 hours were analyzed through an ELISA-based assay (see “Nuclear extractions and transcription factor activity assays” for details). The histogram represents the relative DNA-binding levels of NF-κB (NF-κB p50, NF-κB p65, c-Rel), AP-1 (c-Jun, c-Fos, FosB, JunB, JunD, Fra-1, Fra-2), and several other MAPK-regulated (CREB-1, ATF-2, c-Myc, STAT-1, Mef-2) transcription factors. Data represent the average plus or minus SEM from 3 different experiments (*P < .05, vs msiRNA-2).