Figure 2. A) Dexamethasone inhibits TNF--induced CD38 mRNA expression in HASM cells. Results of quantitative real-time PCR shown as fold change in CD38 mRNA expression in control cells and in cells treated with 50 ng/ml TNF- for 22 h alone, or TNF- in the presence of 0.01, 0.1, and 1 µM dexamethasone. C + D refers to cells exposed to 1 µM dexamethasone. Different letters denote significant (P<0.05) differences between treatments in this and other figures. Note significant inhibition of TNF--induced CD38 expression in the presence of 0.1 and 1 µM dexamethasone; n = 5. Values are mean ± SE in this and other figures. B) Nuclear extracts were prepared from HASM cells and assayed for NF-B binding to ³²P end-labeled NF-B oligonucleotide probe by EMSA. Effect of different concentrations of dexamethasone pretreatment (1 h) on TNF- (10 ng/ml)-induced NF-B activation was also measured. Specificity of NF-B binding was determined using 100-fold excess of unlabeled probe as well as a nonspecific competitor (activating protein-2). Specificity of NF-B complex is demonstrated by gel supershift using p65 or the p50 antibody. Note TNF--induced NF-B activation is decreased by 1 µM dexamethasone as well as by the NF-B inhibitory peptides (SN-50 and SN-50M). Representative of 3 assays.