A novel CC chemokine receptor 4 antagonist RS-1269 inhibits ovalbumin-induced ear swelling and lipopolysaccharide-induced endotoxic shock in mice.

There is growing evidence that chemokines recruit leukocytes in allergic, inflammatory and immune responses. CC chemokine receptor 4 (CCR4) is implicated as a preferential marker for T helper 2 cells, and the cells selectively respond to CC chemokine ligand 17 (CCL17) and CCL22. We searched for compounds having a profile as a CCR4 antagonist from an in-house library and have previously reported that 3-{2-[(2R)-2-phenyl-4-(4-pyridin-4-ylbenzyl)morpholin-2-yl]ethyl}quinazoline-2,4(1H,3H)-dione (named RS-1154) was capable of significantly inhibiting the binding of [(125) I]CCL17 to human CCR4-expressing CHO cells. From further synthesis of its derivatives, we newly focused on 3-(isobutyrylamino)-N-{2-[(2R)-2-phenyl-4-(4-pyridin-4-ylbenzyl)morpholin-2-yl]ethyl}benzamide (RS-1269), which showed potency comparable to RS-1154 in inhibiting CCL17-induced migration of DO11.10 mice-derived T helper 2 cells with an IC(50) value of 5.5 nM in vitro. We then investigated the pharmacological effects of RS-1269 on ovalbumin-induced ear swelling and lipopolysaccharide-induced endotoxic shock in mice. The ear thickness was significantly decreased by oral administration of RS-1269 at the dose of 30 mg/kg. Treatment with lipopolysaccharide significantly increased the serum level of tumour necrosis factor-α. Compared with an anti-CCL17 antibody, RS-1269 significantly inhibited the production at the dose of 100 mg/kg. These results raise the possibility that RS-1269 or one of its derivatives has potential to serve as a prototype compound to develop therapeutic agents for atopic dermatitis and inflammatory diseases.

Novel CC chemokine receptor 4 antagonist RS-1154 inhibits ovalbumin-induced ear swelling in mice.

CC chemokine ligand 17 (CCL17/thymus and activation-regulated chemokine: TARC) and CCL22 (macrophage-derived chemokine: MDC) selectively bind to CC chemokine receptor 4 (CCR4). The CCR4 system is considered to be responsible for the pathology of allergic diseases such as atopic dermatitis. To find and develop potential medicines against allergic diseases, we screened an in-house library to search for compounds having a profile as a CCR4 antagonist. From among the screening hits, we focused on 3-{2-[(2R)-2-phenyl-4-(4-pyridin-4-ylbenzyl)morpholin-2-yl]ethyl}quinazoline-2,4(1H,3H)-dione (named RS-1154), which had been newly synthesized in our laboratory. This compound inhibited the binding of [(125)I]CCL17 to human CCR4-expressing CHO cells with an IC(50) value of 27.7 nM and moreover inhibited CCL17-induced migration of DO11.10 mice-derived T helper 2 cells with an IC(50) value of 1.5 nM in vitro. We then examined the effect of RS-1154 in an ovalbumin-induced ear swelling assay. The ear thickness was decreased by intravenous administration of anti-CCL17 or anti-CCL22 antibodies, suggesting that the CCR4 system is involved in the ear swelling. Though partially, the oral administration of RS-1154 also significantly ameliorated the ear swelling at the doses of 30 and 100 mg/kg. Furthermore, the serum level of interleukin-4 decreased after the administration of RS-1154. In this study, we succeeded in obtaining a newly-synthesized compound, RS-1154, which has a potential to inhibit the chemotaxis of T helper 2 cells in vitro and to ameliorate ovalbumin-induced ear swelling in vivo. These results raise the possibility that RS-1154 or one of derivatives might become a therapeutic agent for atopic dermatitis patients.

Deorphanization of Dresden G protein-coupled receptor for an odorant receptor.

Dresden G protein-coupled receptor (D-GPCR) is one of orphan G protein-coupled receptors (GPCR). Here we report the identification of the ligands and the characterization of D-GPCR. We investigated over 5000 compounds to evoke the response mediated by D-GPCR and identified 3-methyl-valeric acid and 4-methyl-valeric acid as agonists using a cAMP assay. It is of interest that they dramatically enhanced the intracellular cAMP accumulation and the CRE-luciferase activity in CHO-K1 cells and HEK293 cells expressing the chimeric protein of D-GPCR with a rhodopsin-tag at its N-terminus. Our results established new characteristics of D-GPCR as an olfactory receptor. First, agonists of D-GPCR belong to odorants. Second, D-GPCR mRNA is expressed in the olfactory bulb. In addition, D-GPCR was reported to have similar sequences and its genome locus nearby other olfactory receptors. These results suggest D-GPCR is an olfactory receptor.