Regulation of CCL2 Gene Expression Figure 7. Activation of the glucocorticoid receptor increases expression of the MKP-1/DUSP1 gene and decreases IL-1b-stimulated p38 MAPK phosphorylation. A, B. 832/13 cells were transfected with either 3X GRE-luciferase (A) or MKP-1- luciferase (B); 24 h post-transfection cells were treated for 4 h with 10 nM Dex, BD or FP. Luciferase promoter activity was quantified and normalized to total cellular protein. #p,0.01 vs. DMSO (black bar), **p,0.01 vs. DMSO. C. 832/13 cells or D. Rat islets were treated with 10 nM Dex, BD or FP for 6 h. E. 832/13 cells were stimulated for 6 h with 0, 0.1, 1 or 10 nM Dex. F. 832/13 cells were treated with 10 nM Dex for 0, 3, 6 or 12 h. B-F. Total RNA was isolated and MKP-1 mRNA abundance was measured and normalized to RS9. @ p,0.1 vs. DMSO, *p,0.05 vs. DMSO, n.s. = not significant vs. DMSO. G. 832/13 cells were treated with 10 nM Dex for 0.5, 1, 2, 4 or 8 h. Immunoblot analysis was performed with antibodies against MKP-1 using b Actin as a control for equal protein loading. The image shown is representative of two independent experiments. Data showing promoter activity and mRNA abundance are represented as means 6 SEM from 3–4 individual experiments. doi:10.1371/journal.pone.0046986.g007 PLOS ONE | www.plosone.org 13 October 2012 | Volume 7 | Issue 10 | e46986