Thrombin induces translocation of c-fos and c-jun to the nucleus and activates the OSM promoter via a putative AP-1 transcription factor binding motif in human monocyte-derived macrophages. (A) MDMs were incubated for 30, 60, 90, and 120 minutes at 37°C with α-thrombin (1 U/mL). Thereafter, nuclear extracts were prepared from these cells and levels of c-fos and c-jun in these extracts were determined as described in “Analysis of specific binding of AP-1 to DNA.” Values are given as x-fold control and represent mean values ± SD of 3 independent determinations performed for 3 different donors. (B) MDMs were transfected with OSM promoter deletion mutant constructs and with a promoter construct with a mutated AP-1 binding motif indicated by X as described in “Transfection of macrophages.” Twenty-four hours after transfection, cells were incubated for 24 hours in the presence (▩) or absence (□) of α-thrombin (1 U/mL). Luciferase activity was determined as described in “Transfection of macrophages” and is given in percentage of control. Values are given in percentage of control and represent mean values ± SD of 3 determinations. Experiments were performed 2 times with MDMs obtained from 2 different donors with similar results. A representative experiment is shown. *P < .001 (c-fos); §P < .001 (c-jun).