were significantly reduced at the 8-, 24- and 48-h time points in the FITCCmpd A-treated mice. IL-4 levels in the Dex-treated mice were also strongly down-regulated, in line with its inhibitory effect on the NF-AT transcription factor. Kinetic analysis of IFN-c protein amounts demonstrated that Cmpd A reduced levels at 8 h compared with the FITC/veh cohort, but at the 24- and 48-h time points the suppressive effect disappeared. Dex had no significant effect on IFN-c protein levels. We next examined the effect of Cmpd A on the protein levels of two pro-inflammatory cytokines previously shown to play a role in cutaneous inflammation, TNF-a and transforming growth factor-b at 24 h post-challenge. TNF-a protein levels are strongly reduced by the two doses of Cmpd A examined. Similarly, Cmpd A reduced the levels of TGF-b, however, not to the same level as Dex treatment. These experiments importantly demonstrate that the oral administration of the CRTH2 antagonist Cmpd A effectively reduced the levels of a number of key pro-inflammatory cytokines produced locally at the site of inflammation. Cmpd A reduced the levels of the CXC chemokines MIP-2 and GRO-a A dermal neutrophilic infiltrate has previously been shown in both human acute 
AD lesions, as well as this FITC model of allergic cutaneous inflammation. Furthermore, other critical cell types in addition to CD4+ T lymphocytes involved mediating allergic contact dermatitis include dermis-localized mast cells and epithelial cells including keratinocytes. These three cell types are capable of producing either or both the CXC chemokines MIP-2, the functional analog of human IL-8, and GRO-a. Both these chemokines have the ability to recruit neutrophils to sites of skin inflammation. We wanted to investigate whether blocking CRTH2 would impact the production of these CXC chemokines and the subsequent neutrophil influx. Mice were administered Cmpd A 1 h prior to FITC ear challenge, and GRO-a and MIP-2 protein levels were measured at 8 and 24 h. Cmpd A had little effect on the chemokine levels at 8 h; however, there was a significant decrease in both MIP-2 and GRO-a protein at 24 h. Challenged ears from mice of the same cohort were isolated at 24 h and stained for the expression of GR-1, a glycosyl-phosphatidylinositol-linked protein 86 FITC-induced skin inflammation is CRTH2 dependent Fig. 2. Heatmap of select genes down-regulated in FITC-challenged ears treated with Cmpd A at 4, 8 and 24 h. Total RNA was extracted and analyzed using purchase 345627-80-7 Illumina BeadArrays. Levels of gene expression were investigated in four treatment groups at 4-, 8- and 24-h time points using Illumina BeadArrays. The groups included Veh-treated animals, challenged animals/drug Veh, challenged animals/Cmpd A treated and challenged animals/ Dex. The array PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19825579 data are representative of three independent experiments. The fold changes are noted on the respective color scales. In the clustergrams, genes are grouped into cytokines, cytokine receptors, CC chemokines, CC chemokine receptors and CXC chemokines. CD antigens, mucin cluster and adenosine pathway. arachidonic acid pathway, signaling molecules and transcription factors. Levels of S100 calcium-binding protein A9 , as determined by RTqPCR. The data were normalized relative to b-actin and are presented as fold increases or decreases between FITC + Veh/veh, FITC + Cmpd A/FITC and FITC + Dex/FITC-treated mice. The RTqPCR is representative of two independent experiments performed in duplic