GR and PPARγ Function in a Combinatorial Manner to Inhibit LPS Responses (A) Combinatorial interactions between GR and PPARγ agonists at a genome-wide level. Peritoneal macrophages were stimulated with LPS in the absence or presence of Dex alone, GW7845 alone, or the combination of Dex plus GW7845. Each agonist was used at 1 μM. The panel illustrates LPS-target genes exhibiting a > 40% reduction of the LPS response in the presence of at least one agonist. Effects of agonists on the LPS response are color coded according to the legend in Figure 1C. Red arrows indicate genes in which one agonist abolished strong inhibitory effects of the other agonist. Blue arrows indicate genes in which the combination of Dex and GW7845 resulted in stronger inhibition of the LPS response than either agonist alone. Expression data was collected using Affymetrix U74A microarrays and represents results obtained from two independent experiments. (B) Confirmation of combinatorial effect of GR and PPARγ agonists on regulation of LPS-target genes by Northern blotting. Macrophages were treated with LPS for 6 h in the presence of the indicated concentrations (10 nM, 1 μM) of agonists. (C) Confirmation of combinatorial effect of GR and LXR agonists on regulation of LPS-target genes by Northern blotting. (D) Confirmation of combinatorial effect of GR and PPARγ agonists (1 μM) on iNOS expression by real-time quantitative PCR. (E) Combinatorial interactions between GR and PPARγ at the promoter levels. RAW 264.7 cells were transfected with a luciferase reporter plasmid under transcriptional control of the iNOS promoter, PPARγ and RXRα expression plasmids. Cells were treated with the indicated combinations of LPS (100 ng/ml), Dex (10 nM, 1 μM) and GW7845 (10 nM, 1 μM), analyzed for luciferase activity 24 h later. (F) In vivo effects of combinations of GR and PPARγ agonists on the response to intraperitoneal injection of LPS. Six C57BL6 mice were pretreated with the indicated combinations of GW7845 (1 mg/kg) and Dex (1 mg/kg) for 7 days, injected intraperitoneally with LPS (1 mg) and circulating levels of IL-12 p40 were measured by ELISA 8 h later. (G) In vivo effects of combinations of GR and LXR agonists on the response to intraperitoneal injection of LPS. Six C57BL6 mice were pretreated with the indicated combinations of Dex (1 mg/kg) and T1317 (10 mg/kg) for 7 days, injected intraperitoneally with LPS (1 mg) and circulating levels of TNFα were measured by ELISA 6 h later.