H-2g induces IκB phosphorylation by IKKβ labeled with γ–[³²P] ATP, which in turn causes NFκB activation in HMVECs. The effect is inhibited by JAK2 and PI3 kinase inhibitors, and antisense ODNs directed against JAK2 and PI3K. HMVECs were stimulated with H-2g (100 nM) for 15 minutes. (A) In the inhibition study, HMVECs were pretreated with AG490 (50 μM), LY294002 (20 μM), or PD98059 (20 μM) for 2 hours before stimulation with H-2g, and inhibitors were also present during the stimulation with H-2g. AG490 and LY294002 inhibited H-2g–induced EC NFκB while PD98059 had no effect. (B) Transient transfection of HMVECs with sense (▪) and antisense (□) ODNs to JAK2, PI3K, and Erk1/2 confirmed the results obtained using chemical inhibitors: JAK2 and PI3K antisense ODNs inhibited H-2g–induced EC IKKβ activation. Nontransfected cells were used as a control. Results are representative of 4 independent experiments. ^* indicates a significant difference (P < .05) between the respective groups.