CCR3 antagonist 1

Macrophage inflammatory protein-1

Macrophage inflammatory protein (MIP)-1alpha was identified 15 years ago as the first of now four members of the MIP-1 CC chemokine subfamily. These proteins termed CCL3 (MIP-1alpha), CCL4 (MIP-1beta), CCL9/10 (MIP-1delta), and CCL15 (MIP-1gamma) according to the revised nomenclature for chemokines are produced by many cells, particularly macrophages, dendritic cells, and lymphocytes. MIP-1 proteins, which act via G-protein-coupled cell surface receptors (CCR1, 3, 5), e.g. expressed by lymphocytes and monocytes/macrophages (MPhi), are best known for their chemotactic and proinflammatory effects but can also promote homoeostasis. The encouraging results of preclinical studies in murine models of inflammation, i.e. asthma, arthritis, or multiple sclerosis, have led to the development of potent CCR3 and 5 antagonists, some of which are currently being tested in first clinical trials.

A small molecule antagonist of chemokine receptors CCR1 and CCR3. Potent inhibition of eosinophil function and CCR3-mediated HIV-1 entry

We describe a small molecule chemokine receptor antagonist, UCB35625 (the trans-isomer J113863 published by Banyu Pharmaceutical Co., patent WO98/04554), which is a potent, selective inhibitor of CCR1 and CCR3. Nanomolar concentrations of UCB35625 were sufficient to inhibit eosinophil shape change responses to MIP-1alpha, MCP-4, and eotaxin, while greater concentrations could inhibit the chemokine-induced internalization of both CCR1 and CCR3. UCB35625 also inhibited the CCR3-mediated entry of the human immunodeficiency virus-1 primary isolate 89.6 into the glial cell line, NP-2 (IC(50) = 57 nm). Chemotaxis of transfected cells expressing either CCR1 or CCR3 was inhibited by nanomolar concentrations of the compound (IC(50) values of CCR1-MIP-1alpha = 9.6 nm, CCR3-eotaxin = 93.7 nm). However, competitive ligand binding assays on the same transfectants revealed that considerably larger concentrations of UCB35625 were needed for effective ligand displacement than were needed for the inhibition of receptor function. Thus, it appears that the compound may interact with a region present in both receptors that inhibits the conformational change necessary to initiate intracellular signaling. By virtue of its potency at the two major eosinophil chemokine receptors, UCB35625 is a prototypic therapy for the treatment of eosinophil-mediated inflammatory disorders, such as asthma and as an inhibitor of CCR3-mediated human immunodeficiency virus-1 entry.

CCR3 antagonist impairs estradiol-induced eosinophil migration to the uterus in ovariectomized mice

Eosinophils are abundant in the reproductive tract, contributing to the remodeling and successful implantation of the embryo. However, the mechanisms by which eosinophils migrate into the uterus and their relationship to edema are still not entirely clear, since there are a variety of chemotactic factors that can cause migration of these cells. Therefore, to evaluate the role of CCR3 in eosinophil migration, ovariectomized C57BL/6 mice were treated with CCR3 antagonist SB 328437 and 17β-estradiol. The hypothesis that the CCR3 receptor plays an important role in eosinophil migration to the mouse uterus was confirmed, because we observed reduction in eosinophil peroxidase activity in these antagonist-treated uteruses. The antagonist also influenced uterine hypertrophy, inhibiting edema formation. Finally, histological analysis of the orcein-stained uteruses showed that the antagonist reduced eosinophil migration together with edema. These data showed that the CCR3 receptor is an important target for studies that seek to clarify the functions of these cells in uterine physiology.

Novel peptide nanoparticle-biased antagonist of CCR3 blocks eosinophil recruitment and airway hyperresponsiveness

Background: Chemokine signaling through CCR3 is a key regulatory pathway for eosinophil recruitment into tissues associated with allergic inflammation and asthma. To date, none of the CCR3 antagonists have shown efficacy in clinical trials. One reason might be their unbiased mode of inhibition that prevents receptor internalization, leading to drug tolerance.
Objective: We sought to develop a novel peptide nanoparticle CCR3 inhibitor (R321) with a biased mode of inhibition that would block G protein signaling but enable or promote receptor internalization.
Methods: Self-assembly of R321 peptide into nanoparticles and peptide binding to CCR3 were analyzed by means of dynamic light scattering and nuclear magnetic resonance. Inhibitory activity on CCR3 signaling was assessed in vitro by using flow cytometry, confocal microscopy, and Western blot analysis in a CCR3⁺ eosinophil cell line and blood eosinophils. In vivo effects of R321 were assessed by using a triple-allergen mouse asthma model.
Results: R321 self-assembles into nanoparticles and binds directly to CCR3, altering receptor function. Half-maximal inhibitory concentration values for eotaxin-induced chemotaxis of blood eosinophils are in the low nanomolar range. R321 inhibits only the early phase of extracellular signal-regulated kinase 1/2 activation and not the late phase generally associated with β-arrestin recruitment and receptor endocytosis, promoting CCR3 internalization and degradation. In vivo R321 effectively blocks eosinophil recruitment into the blood, lungs, and airways and prevents airway hyperresponsiveness in a mouse eosinophilic asthma model.
Conclusions: R321 is a potent and selective antagonist of the CCR3 signaling cascade. Inhibition through a biased mode of antagonism might hold significant therapeutic promise by eluding the formation of drug tolerance.

Suppression of laser-induced choroidal neovascularization by a CCR3 antagonist

Purpose: To evaluate the efficacy of a novel CCR3 antagonist for laser injury-induced choroidal neovascularization (CNV) in mice.
Methods: We evaluated YM-344031, a novel and selective small-molecule CCR3 antagonist. CNV was induced by laser injury in C57BL/6J mice, and its volume was measured after 7 days by confocal microscopy. Leakage from the CNV was also measured after 7 days by fluorescein angiography. The CCR3 antagonist was administered by gavage at 1 hour before and 1 day after the laser injury, or intravitreous injection immediately after the laser injury. After the laser injury, ELISA, Western blot analysis, and real-time RT-PCR for VEGF-A expression in the RPE/choroid, and immunohistochemistry for CCR3, CCL11, Ki67, and Rac1 was performed.
Results: Both oral administration and intravitreous injection of YM-344031 significantly suppressed the CNV volume (P < 0.0001 and P < 0.01, respectively). Pathologically significant leakage was significantly less common in YM-344031-injected mice (P < 0.0001). The mean VEGF protein level was significantly increased in vehicle-injected eyes after the laser injury (P < 0.05). Although the YM-344031-injected eyes did not show VEGF-A suppression after the laser injury, VEGF164 mRNA upregulation was significantly suppressed in YM-344031-injected mice (P < 0.05), and intravitreous injection of YM-344031 appeared to suppress CCR3, CCL11 (eotaxin), Ki67, and Rac1 expression after the laser injury.
Conclusions: The present data suggest that the CCR3 antagonist YM-344031 can suppress CNV, via suppression of the upregulation of VEGF164 mRNA in VEGF isoform after the laser injury. Although our findings may warrant further investigation, YM-344031 may have potential as a new therapy for age-related macular degeneration.