C-C Chemokine Receptor Type 3 Research Articles

Blockade of CC Chemokine Receptor Type 3 Diminishes Pain and Enhances Opioid Analgesic Potency in a Model of Neuropathic Pain.

Neuropathic pain is a serious clinical issue, and its treatment remains a challenge in contemporary medicine. Thus, dynamic development in the area of animal and clinical studies has been observed. The mechanisms of neuropathic pain are still not fully understood; therefore, studies investigating these mechanisms are extremely important. However, much evidence indicates that changes in the activation and infiltration of immune cells cause the release of pronociceptive cytokines and contribute to neuropathic pain development and maintenance. Moreover, these changes are associated with low efficacy of opioids used to treat neuropathy. To date, the role of CC chemokine receptor type 3 (CCR3) in nociception has not been studied. Similarly, little is known about its endogenous ligands (C-C motif ligand; CCL), namely, CCL5, CCL7, CCL11, CCL24, CCL26, and CCL28. Our research showed that the development of hypersensitivity in rats following chronic constriction injury (CCI) of the sciatic nerve is associated with upregulation of CCL7 and CCL11 in the spinal cord and dorsal root ganglia (DRG). Moreover, our results provide the first evidence that single and repeated intrathecal administration of the CCR3 antagonist SB328437 diminishes mechanical and thermal hypersensitivity. Additionally, repeated administration enhances the analgesic properties of morphine and buprenorphine following nerve injury. Simultaneously, the injection of SB328437 reduces the protein levels of some pronociceptive cytokines, such as IL-6, CCL7, and CCL11, in parallel with a reduction in the activation and influx of GFAP-, CD4- and MPO-positive cells in the spinal cord and/or DRG. Moreover, we have shown for the first time that an inhibitor of myeloperoxidase-4-aminobenzoic hydrazide may relieve pain and simultaneously enhance morphine and buprenorphine efficacy. The obtained results indicate the important role of CCR3 and its modulation in neuropathic pain treatment and suggest that it represents an interesting target for future investigations.

A multi-cellular molecular signaling and functional network map of C-C motif chemokine ligand 18 (CCL18): a chemokine with immunosuppressive and pro-tumor functions.

The C-C Motif Chemokine Ligand 18 (CCL18) is a beta-chemokine sub-family member with immunomodulatory functions in primates. CCL18-dependent migration and epithelial-to-mesenchymal transition of oral squamous cell carcinoma, squamous cell carcinoma of head and neck, breast cancer, hepatocellular carcinoma, non-small cell lung carcinoma, ovarian cancer, pancreatic ductal carcinoma and bladder cancer cells are well-established. In the tumor niche, tumor-associated macrophages produce CCL18 and its overexpression is correlated with reduced patient survival in multiple cancers. Although multiple receptors including C-C chemokine receptor type 3 (CCR3), type 6 (CCR6), type 8 (CCR8) and G-protein coupled estrogen receptor (GPER1) are reported for CCL18, thePhosphatidylinositol Transfer Protein, Membrane-Associated 3 (PITPNM3) receptor is currently considered as its predominant receptor. Characterization of the molecular events and check points associated with the immunosuppressive and cancer progression support functions induced by CCL18 for their potential towards therapeutic applications is an area of active research. Hence, in this study, we assembled 917 signaling events reported to be induced by CCL18 through their studied receptors in diverse cell types as an integrated knowledgebase for reference, data integration and gene-set enrichment analysis of global transcriptomic and/or proteomics datasets.

CCR3 gene overexpression in patients with Down syndrome.

Chromosome 21 trisomy or Down syndrome (DS) is the most common genetic cause of intellectual disability (ID). DS is also associated with hypotonia, muscle weakness, autoimmune diseases, and congenital heart disease. C-C chemokine receptor type 3 (CCR3) plays a role in inflammatory, autoimmune, and neuronal migration mechanisms. The present study aimed to evaluate the expression of the CCR3 gene by NGS and qRT-PCR in patients with DS and normal controls (NC). The CCR3 gene was over-expressed in DS patients compared to NC. These data suggest that an over-expression of the CCR3 gene is associated with the phenotype of patients with DS.

CCR3-shRNA promotes apoptosis and inhibits chemotaxis and degranulation of mouse mast cells.

Mast cells (MCs) are the major effector cells of allergic rhinitis (AR). The present study aimed to investigate the effects of C-C chemokine receptor type 3 (CCR3) on the proliferation, apoptosis, chemotaxis and activated degranulation of mouse MCs. Mouse bone marrow-derived MCs were cultured in vitro, purified and identified using toluidine blue staining and flow cytometry. Three different CCR3-short hairpin (shRNA) lentiviral vectors were constructed and transfected into MCs, and the mRNA and protein expression levels of CCR3 were assessed by reverse transcription-quantitative PCR and western blotting. Proliferation and apoptosis of the MCs were measured using Cell Counting kit-8 (CCK-8) assays and flow cytometry, respectively. MC chemotaxis was assessed by Transwell assay and quantified using flow cytometry. The activation of MC degranulation was examined using ELISAs. The results demonstrated that MCs were appropriately isolated, and identified that CCR3-shRNA2 presented the higher knockdown effect among the three shRNAs tested. Following 96 h of transfection, the results of CCK-8 and flow cytometry assays demonstrated that CCR3-shRNA2 inhibited MC proliferation and promoted MC apoptosis. The results from the Transwell assay indicated that CCR3-shRNA2 restrained MC chemotaxis, whereas ELISA results demonstrated that CCR3-shRNA2 suppressed MC degranulation. In conclusion, CCR3-shRNA2 effectively downregulated CCR3 mRNA and protein expression levels in mouse MCs. In addition, CCR3-shRNA2 promoted MC apoptosis and suppressed the proliferation, chemotaxis and degranulation of mouse MCs, suggesting that CCR3-shRNA2 may serve as a therapeutic tool for the treatment of allergic rhinitis.

Estrogen regulates the proliferation and inflammatory expression of primary stromal cell in benign prostatic hyperplasia.

BackgroundTo investigate the expression of estrogen receptor (ER) in prostate tissues of benign prostatic hyperplasia (BPH) individuals, and the effects of estrogen regulating the proliferation and inflammatory expressions of primary prostate stromal cells in BPH.MethodsA total of 44 human BPH prostate tissues were collected to explore the expression of ER by immunohistochemistry (IHC). Cell proliferation, mRNA and protein expressions were analyzed in primary prostate stromal cells treated with estrogen or estrogen plus fulvestrant through cell count kit-8 (CCK-8) assay, quantitative real-time polymerase chain reaction (qPCR), IHC and western blot, respectively.ResultsFirstly, ERβ was positive, and ERα was negative in the transition zone of prostate among all the 44 individuals with BPH. Secondly, the effects could be partially inhibited by fulvestrant, of estrogen promoting the proliferation of primary prostate stromal cells cultured in dulbecco’s modified eagle medium (DMEM) supplemented with 2% fetal bovine serum (FBS). Thirdly, estrogen up-regulates the mRNA levels of C-C chemokine receptor type 3 (CCR3), CD40 ligand (CD 40L), C-X-C motif chemokine ligand 9 (CXCL9) and interleukin 10 (IL10), and down-regulates the mRNA levels of C-C chemokine receptor type 4 (CCR4) and interleukin 17C (IL17C). Then, the protein expressions of CCR3, CCR4, CD40L, IL10 and IL17C are positive, and CXCL9 is negative in the third-generation primary prostate stromal cells. Finally, the effects could be partially inhibited by fulvestrant, of estrogen up-regulating the protein levels of CD40L and IL10.ConclusionsThe expressions of ER in human BPH prostate tissues are zone-dependent. Estrogen promoting the proliferation of primary prostate stromal cells cultured in DMEM supplemented with 2% FBS. The expressions of CCR3, CCR4, CD 40L, IL17C, CXCL9 and IL10 are regulated by estrogen in primary prostate stromal cells.

Bioinformatic analysis of eosinophil activity and its implications for model and target species.

Eosinophils are important immune cells that have been implicated in resistance to gastrointestinal nematode (GIN) infections in both naturally and experimentally infected sheep. Proteins of particular importance appear to be IgA-Fc alpha receptor (FcαRI), C-C chemokine receptor type 3 (CCR3), proteoglycan 3 (PRG3, major basic protein 2) and EPX (eosinophil peroxidase). We used known human nucleotide sequences to search the ruminant genomes, followed by translation to protein and sequence alignments to visualize differences between sequences and species. Where a sequence was retrieved for cow, but not for sheep and goat, this was used additionally as a reference sequence. In this review, we show that eosinophil function varies among host species. Consequently, investigations into the mechanisms of ruminant immune responses to GIN should be conducted using the natural host. Specifically, we address differences in protein sequence and structure for eosinophil proteins.

Role of eosinophils in a murine model of inflammatory bowel disease

Ulcerative colitis (UC) is a form of inflammatory bowel disease (IBD), which is triggered spontaneously by unknown mechanisms and manifests as chronic and relapsing inflammatory conditions in the colon. Eosinophil infiltration is often observed in the colonic tissue of ulcerative colitis patients. However, the role of eosinophils in the disease has not been well defined. The aim of this study is to investigate the role of eosinophils in colonic inflammation using the murine model of spontaneous colitis. CC chemokine receptor type 3 (CCR3) and interleukin (IL)-10 double knockout mice (CCR3−/−;IL-10−/−) were utilized to evaluate the function of eosinophils in colitis. The levels of colitis were evaluated by colonoscopy, histology, and real-time PCR measurements to determine expression levels of inflammatory cytokines in the colonic tissue. The levels of cytokines produced by T cells in mesenteric lymph nodes were evaluated by ELISA. There was no significant difference in endoscopic and histological scores between the groups of CCR3−/−;IL-10−/− mice and control CCR3+/−;IL-10−/− mice. There was also no significant difference in the expression levels of pro-inflammatory cytokines in the intestinal tissue between the two groups. Similar results were found for IL-17A and interferon gamma (IFN-γ) production from mesenteric lymph node-derived T cells. Our data indicate that eosinophils do not play a significant role in the immunopathology of colitis in IL-10−/− mice.

Eotaxins and C-C chemokine receptor type 3 in Parkinson's disease.

Parkinson's disease (PD) is one of the most common neuroinflammatory disorders and inflammatory processes seem to play an important role in the pathogenesis of PD. Chemokines as inflammatory mediators, which are involved in the recruitment of leukocytes, can play a role in the pathogenesis of PD. The aim of this study was to examine the serum level of eotaxins (CCL11, CCL24, and CCL26) and the expression of C-C chemokine receptor type 3 (CCR3) in patients with PD compared with healthy subjects. In this study, we measured the serum levels of CCL11, CCL24, and CCL26 with ELISA. In addition, gene and protein expression of CCR3 were measured by RT-PCR and flow cytometry techniques in PD patients (n = 30) and age- and sex-matched healthy subjects (n = 30). All patients suffering from PD were assessed clinically through Unified Parkinson's Disease Rating Scale, Motor Examination (UPDRS ME). The results of this study showed that there was no significant alteration in the serum level of these chemokines and also their receptor among patients with PD and healthy subjects. No significant correlation was observed between the eotaxins serum levels and the clinical measures of PD severity. Based on the results, it can be concluded that eotaxins cannot be considered as appropriate targets for the diagnosis or treatment of PD.

C‑C chemokine receptor type 3 gene knockout alleviates inflammatory responses in allergic rhinitis model mice by regulating the expression of eosinophil granule proteins and immune factors.

The present study aimed to investigate the effects of C-C chemokine receptor type 3 (CCR3) gene knockout on allergic rhinitis (AR) in mice, as well as the underlying molecular mechanisms. Ovalbumin was administrated to CCR3+/+ and CCR3−/− BALB/c mice to establish an AR model. The mice were divided into four groups: i) Normal control (CG), ii) AR model (AR), iii) CCR3 knockout CG (CCR3−/−CG) and iv) AR model with CCR3 knockout (CCR3−/−AR). Histological sections of nasal mucosae were examined by hematoxylin and eosin staining, which revealed that CCR3 knockout suppressed the invasion of inflammatory cells and relieved the damage of nasal mucosae. Peripheral blood smear and nasal-washing smears were evaluated by Wright's staining. Eosinophil (EOS) numbers in nasal mucosae, peripheral blood, and nasal washings of the various groups were ranked in the order: AR>CCR3−/−AR>CG>CCR3−/−. mRNA expression levels of CCR3, EOS peroxidase (EPO), EOS cationic protein (ECP), and major basic protein (MBP) in the peripheral serum and nasal washings were detected by reverse transcription-polymerase chain reaction. Interferon-γ (IFN-γ), interleukin (IL)-4, IL-10, and immunoglobulin E (IgE) protein levels in the peripheral serum and nasal washings were investigated by ELISA. CCR3 mRNA expression was not detected in the CCR3−/− and CCR3−/−AR groups, whereas expression levels in the AR group were markedly higher compared with expression in the CG group. Compared with the CG-associated groups (i.e., the CG and CCR3−/−CG groups), the levels of EPO, ECP, MBP, IL-4, and IgE were significantly increased in the AR-associated groups (that is, R and CCR3−/−AR). In addition, the CCR3−/−AR group mice produced significantly lower levels of EPO, ECP, MBP, IL-4 and IgE compared with the AR group, whereas the expression levels of IFN-γ and IL-10 were increased. CCR3 gene knockout may alleviate EOS invasion and the inflammatory response in AR model mice by reducing the expression levels of EPO, ECP, MBP, IL-4, and IgE, and increasing the expression of IL-10 and IFN-γ.

Exopolysaccharide from Bifidobacterium longum subsp. longum 35624™ modulates murine allergic airway responses.

Interactions between the host and the microbiota are thought to significantly influence immunological tolerance mechanisms at mucosal sites. We recently described that the loss of an exopolysaccharide (EPS) from Bifidobacterium longum 35624™ eliminated its protective effects in colitis and respiratory allergy murine models. Our goal was to investigate the immune response to purified EPS from B. longum 35624, determine if it has protective effects within the lung and identify the protective mechanisms. Isolated EPS from B. longum 35624 cultures was used for in vitro, ex vivo and in vivo studies. Human monocyte-derived dendritic cells (MDDCs) were used to investigate in vitro immunological responses to EPS. Cytokine secretion, expression of surface markers and signalling pathways were examined. The ovalbumin (OVA) respiratory allergy murine model was used to evaluate the in vivo immunomodulatory potential of EPS. In addition, interleukin (IL)-10 knockout (KO) mice and anti-Toll-like receptor (TLR)-2 blocking antibody were used to examine the underlying protective mechanisms of intranasal EPS administration. Stimulation of human MDDCs with EPS resulted in IL-10 secretion, but not proinflammatory cytokines. IL-10 secretion was TLR-2-dependent. Eosinophil recruitment to the lungs was significantly decreased by EPS intranasal exposure, which was associated with decreased expression of the Th2-associated markers C-C motif chemokine 11 (CCL11), C-C chemokine receptor type 3 (CCR3), IL-4 and IL-13. TLR-2-mediated IL-10 secretion was shown to be required for the reduction in eosinophils and Th2 cytokines. EPS-treatment reduced eosinophil recruitment within the lung in a respiratory inflammation mouse model, which is both TLR-2 and IL-10 mediated. EPS can be considered as a novel molecule potentially reducing the severity of chronic eosinophil-related airway disorders.

Functional expression of CCL8 and its interaction with chemokine receptor CCR3

BackgroundChemokines and their cognate receptors play important role in the control of leukocyte chemotaxis, HIV entry and other inflammatory diseases. Developing an effcient method to investigate the functional expression of chemokines and its interactions with specific receptors will be helpful to asses the structural and functional characteristics as well as the design of new approach to therapeutic intervention.ResultsBy making systematic optimization study of expression conditions, soluble and functional production of chemokine C-C motif ligand 8 (CCL8) in Escherichia coli (E. coli) has been achieved with approx. 1.5 mg protein/l culture. Quartz crystal microbalance (QCM) analysis exhibited that the purified CCL8 could bind with C-C chemokine receptor type 3 (CCR3) with dissociation equilibrium constant (KD) as 1.2 × 10−7 M in vitro. Obvious internalization of CCR3 in vivo could be detected in 1 h when exposed to 100 nM of CCL8. Compared with chemokine C-C motif ligand 11 (CCL11) and chemokine C-C motif ligand 24 (CCL24), a weaker chemotactic effect of CCR3 expressing cells was observed when induced by CCL8 with same concentration.ConclusionThis study delivers a simple and applicable way to produce functional chemokines in E. coli. The results clearly confirms that CCL8 can interact with chemokine receptor CCR3, therefore, it is promising area to develop drugs for the treatment of related diseases.

Expression of CCR3, SOX5 and LC3 in patients with elderly onset rheumatoid arthritis and the clinical significance.

This study investigated the expression of C-C chemokine receptor type 3 (CCR3), transcription factor SOX5 (SOX5) and microtubule-associated protein 1 light chain 3 (LC3) in patients with elderly onset rheumatoid arthritis (EORA) and the clinical significance. Ninety patients with elderly onset rheumatoid arthritis were selected in our hospital from January to December in 2016 to serve as patient group. At the same time, 50 healthy people were selected as control group. Levels of CCR3, SOX5 and LC3 in serum of two groups were detected by enzyme-linked immunosorbent assay (ELISA). Expression levels of CCR3, SOX5 and LC3 mRNA in peripheral blood mononuclear cells (PBMCs) were detected by reverse transcription-PCR (RT-PCR). Expression level of CCR3 mRNA in patient group was 0.752±0.054, which was significantly higher than that in control group (0.287±0.032, t=8.932, P<0.05). Levels of CCR3, SOX5 and LC3 in serum of patients in patient group were significantly higher than those in control group (P<0.05). Positive correlations were found between serum levels of CCR3 and SOX5 (r=0.613, P<0.05), serum levels of CCR3 and LC3 (r=0.637, P<0.05), and serum levels of SOX5 and LC3 (r=0.645, P<0.05). CCR3, SOX5 and LC3 are highly expressed in PBMC and serum, which may be closely related to the occurrence and development of EORA. These indexes may be used as indicators of clinical diagnosis and prognosis of patients with EORA.

CCR3 Is Associated with the Death of a Photoreceptor Cell-line Induced by Light Exposure.

The C-C chemokine receptor type 3 (CCR3) is the receptor for eotaxins (CCL-11, 24, 26), RANTES (CCL-5) and MCP-3 (CCL-7). It was reported that an inhibition of CCR3 by antagonists or antibodies reduces the degree of laser-induced choroidal neovascularization in mice, a model for wet age-related macular degeneration (AMD). Although several chemokine receptors have the potential of reducing the degree of the chronic inflammation in experimental dry AMD, the association of CCR3 remains unknown. The purpose of this study was to determine the role played by CCR3 in the death of 661W cells which are cells of a murine photoreceptor-derived cell line as an in vitro model of dry AMD. The expression of CCR3 was increased in the 661W cells after light exposure. Inhibition of CCR3 reduced the rate of cell death induced by light exposure. A blockade of CCR3 signaling by CCR3 silencing and two kinds of CCR3 antagonists, SB 328437 and SB 297006, reduced the rate of light-induced cell death. In addition, CCR3 inhibition decreased the level of reactive oxygen species and the activation of caspase-3/7 induced by light exposure. These findings indicated that the CCR3 blockade should be considered for the treatment of the dry AMD.

Role of Interleukin-17A on the Chemotactic Responses to CCL7 in a Murine Allergic Rhinitis Model.

BackgroundThe proinflammatory cytokine interleukin (IL)-17A is associated with eosinophil infiltration into the nasal mucosa in a mouse model of ovalbumin-induced allergic rhinitis. Chemotaxis of eosinophils is mediated primarily through C-C chemokine receptor type 3 (CCR3). However, the mechanism underlying the IL-17A-mediated enhancement of eosinophil recruitment via chemoattractants/chemokines remains unknown.ObjectivesIn this study, we assessed the contribution of IL-17A to eosinophil-related inflammation via the CCL7/CCR3 pathway in experimental allergic rhinitis.MethodsIL-17A knockout (KO) and wild-type (WT) BALB/c mice were injected intraperitoneally and challenged intranasally with OVA to induce allergic rhinitis. Various parameters of the allergic response were evaluated, and mRNA and protein levels of CCL7 and CCR3 in nasal tissue and serum were compared between the two groups. The chemotactic response to CCL7 with or without IL-17A in bone marrow-derived eosinophils (bmEos) from BALB/c mice was measured.ResultsIn the allergic rhinitis model, IL-17A deficiency significantly decreased nasal symptoms, serum IgE levels, and eosinophil recruitment to the nasal mucosa. CCL7 and CCR3 mRNA and protein levels were decreased in the nasal mucosa of IL-17A KO mice compared with the WT mice. BmEos showed a significantly increased chemotactic response to -low concentration of CCL7 in the presence of IL-17A compared with its absence.ConclusionThe suppression of nasal inflammation due of IL-17A deficiency in allergic rhinitis is partly responsible for the regulation of CCL7 secretion and eosinophil infiltration, which may be regulated via the CCL7/CCR3 pathway.

High-level production of biologically active chemokines in Escherichia coli

The chemokines eotaxin-1 (CCL11) and eotaxin-2 (CCL24), belonging to the CC chemokines family, play key roles in the inflammatory response, allergic asthma and other diseases. When expressed in Escherichia coli, chemokines are prone to form inclusion bodies devoid of biological activity, and it is hard to refold them properly. Here an expression and purification protocol for high-level production of soluble and biologically active CCL11 and CCL24 in E. coli has been established. A final yield of 8.7mg/l for CCL11 and 3.9mg/l for CCL24 has been obtained and the purified proteins were characterized with SDS-PAGE, mass spectrometry and circular dichroism. High binding affinity of purified chemokines with CC chemokine receptor type 3 (CCR3) has been confirmed with surface plasmon resonance (SPR) and the KD values are 3.7×10−7M and 3.0×10−7M, respectively, for CCL11 and CCL24. This report provides a straightforward strategy for the efficient production of soluble and biologically active chemokines in E. coli.

Eosinophil adoptive transfer system to directly evaluate pulmonary eosinophil trafficking in vivo

Most in vivo studies of granulocytes draw conclusions about their trafficking based on examination of their steady-state tissue/blood levels, which result from a combination of tissue homing, survival, and egress, rather than direct examination of cellular trafficking. Herein, we developed a unique cell transfer system involving the adoptive transfer of a genetically labeled, bone-marrow-derived unique granulocyte population (eosinophils) into an elicited inflammatory site, the allergic lung. A dual polychromatic FACS-based biomarker-labeling system based on the IL4-eGFP transgene (4get) or Cd45.1 allele was used to track i.v. transferred eosinophils into the airway following allergen or T(H)2-associated stimuli in the lung in multiple mouse strains. The system was amenable to reverse tagging of recipients, thus allowing transfer of nonlabeled eosinophils and competitive tracking of multiple populations of eosinophils in vivo. The half-life of eosinophils in the blood was 3 h, and migration to the lung was dependent upon the dosage of transferred eosinophils, sensitive to pertussis toxin pretreatment, peaked at ∼24 h after adoptive transfer, and revealed a greater than 8-d eosinophil half-life in the lung. Eosinophil migration to the lung was dependent upon recipient IL-5 and IL-13 receptor α1 and donor eosinophil C-C chemokine receptor type 3 (CCR3) and interleukin 1 receptor-like 1 (ST2) in vivo. Taken together, this unique eosinophil transfer system provides an unprecedented opportunity to examine airway eosinophil migration without the need for extensive efforts to acquire donor source and time-consuming genetic crossing and has already been used to identify a long eosinophil half-life in the allergic lung and a definite role for ST2 in regulating eosinophil trafficking.

Successful Treatment with Tacrolimus in a Case of the Glucocorticoid-Dependent Recurrent Cutaneous Eosinophilic Vasculitis

Successful Treatment with Tacrolimus in a Case of the Glucocorticoid-Dependent Recurrent Cutaneous Eosinophilic Vasculitis

Upregulation of CCR3 by Age-Related Stresses Promotes Choroidal Endothelial Cell Migration via VEGF-Dependent and -Independent Signaling

To explore the molecular mechanisms by which the C-C chemokine receptor type 3 (CCR3) and chemokine (C-C motif) ligand 11 (CCL11) regulate choroidal endothelial cell (CEC) migration and the interactions with the vascular endothelial growth factor (VEGF) signaling pathway. Human retinal sections from young and aged donor normal eyes were immunolabeled. By real-time PCR, CCR3 mRNA was measured in retinal pigmented epithelium (RPE)/choroids obtained from young and aged human donor eyes and in cultured CECs exposed to hydrogen peroxide. CCR3 ligand and CCL11- or VEGF-stimulated CEC migration was also measured in the presence of the CCR3 inhibitor or control using fluorescence microscopy. Activation of Rac1, phosphorylated Akt as a readout for phosphoinositol 3-kinase signaling, and VEGFR2 activation were measured in CECs incubated with CCL11, VEGF, or combined CCL11/VEGF. CCR3 was expressed to a greater level in older compared with that in younger human retinas or RPE/choroids. Ligand-activated CCR3 increased CEC migration, which was inhibited by the CCR3 inhibitor. Rac1 activity, p-Akt, and p-VEGFR2 were significantly increased in CECs incubated with CCL11. The CCR3 inhibitor prevented VEGF-induced CEC migration and Rac1 activation in CECs. Rac1 activity was additively increased in CECs treated with CCL11 and VEGF compared with that in cells with CCL11 or VEGF treatment alone. Ligand-activated CCR3 caused VEGFR2 phosphorylation and coimmunoprecipitation of VEGFR2 and CCR3. Activated CCR3 promotes CEC migration and Rac1 activation and causes an association with and activation of VEGFR2. Cross-talk between CCR3 and VEGF signaling exists and may be important in choroidal neovascularization in human age-related macular degeneration.