Stimulation of bEnd.3 cells with TNF- plus OSM cooperatively increases mRNA for P- and E-selectin. (A) bEnd.3 cells were treated with 25 ng/mL murine OSM, 100 U/mL murine TNF-, or a combination of both cytokines. After the indicated time, total RNA was isolated and analyzed by Northern blotting. (B) bEnd.3 cells were treated with fresh medium in the presence or absence of 25 ng/mL murine OSM, 100 U/mL murine TNF-, or a combination of both cytokines, in the presence or absence of 10 μg/mL cycloheximide or 5 μg/mL actinomycin D (Act. D). After 3 hours, total RNA was isolated and analyzed by Northern blotting.