Critically-ill COVID-19 susceptibility gene CCR3 shows natural selection in sub-Saharan Africans

The prevalence of COVID-19 critical illness varies across ethnicities, with recent studies suggesting that genetic factors may contribute to this variation. The aim of this study was to investigate natural selection signals of genes associated with critically-ill COVID-19 in sub-Saharan Africans. Severe COVID-19 SNPs were obtained from the HGI website. Selection signals were assessed in 661 sub-Sahara Africans from 1000 Genomes Project using integrated haplotype score (iHS), cross-population extended haplotype homozygosity (XP-EHH), and fixation index (Fst). Allele frequency trajectory analysis of ancient DNA samples were used to validate the existing of selection in sub-Sahara Africans. We also used Mendelian randomization to decipher the correlation between natural selection and critically-ill COVID-19. We identified that CCR3 exhibited significant natural selection signals in sub-Sahara Africans. Within the CCR3 gene, rs17217831-A showed both high iHS (Standardized iHS = 2) and high XP-EHH (Standardized XP-EHH = 2.5) in sub-Sahara Africans. Allele frequency trajectory of CCR3 rs17217831-A revealed natural selection occurring in the recent 1,500 years. Natural selection resulted in increased CCR3 expression in sub-Sahara Africans. Mendelian Randomization provided evidence that increased blood CCR3 expression and eosinophil counts lowered the risk of critically ill COVID-19. Our findings suggest that sub-Saharan Africans are resistant to critically ill COVID-19 due to natural selection and identify CCR3 as a potential novel therapeutic target.

Chemokine profiling of melanoma-macrophage crosstalk identifies CCL8 and CCL15 as prognostic factors in cutaneous melanoma

During cancer evolution, tumor cells attract and dynamically interact with monocytes/macrophages. To find biomarkers of disease progression in human melanoma, we used unbiased RNA sequencing and secretome analyses of tumor-macrophage co-cultures. Pathway analysis of genes differentially modulated in human macrophages exposed to melanoma cells revealed a general upregulation of inflammatory hallmark gene sets, particularly chemokines. A selective group of chemokines, including CCL8, CCL15, and CCL20, was actively secreted upon melanoma-macrophage co-culture. Because we previously described the role of CCL20 in melanoma, we focused our study on CCL8 and CCL15 and confirmed that in vitro both chemokines contributed to melanoma survival, proliferation, and 3D invasion through CCR1 signaling. In vivo, both chemokines enhanced primary tumor growth, spontaneous lung metastasis, and circulating tumor cell survival and lung colonization in mouse xenograft models. Finally, we explored the clinical significance of CCL8 and CCL15 expression in human skin melanoma, screening a collection of 67 primary melanoma samples, using multicolor fluorescence and quantitative image analysis of chemokine-chemokine receptor content at the single-cell level. Primary skin melanomas displayed high CCR1 expression, but there was no difference in its level of expression between metastatic and nonmetastatic cases. By contrast, comparative analysis of these two clinically divergent groups showed a highly significant difference in the cancer cell content of CCL8 (p = 0.025) and CCL15 (p < 0.0001). Kaplan-Meier curves showed that a high content of CCL8 or CCL15 in cancer cells correlated with shorter disease-free and overall survival (log-rank test, p < 0.001). Our results highlight the role of CCL8 and CCL15, which are highly induced by melanoma-macrophage interactions in biologically aggressive primary melanomas and could be clinically applicable biomarkers for patient profiling. © 2024 The Pathological Society of Great Britain and Ireland.

Keras/TensorFlow in Drug Design for Immunity Disorders

Homeostasis of the host immune system is regulated by white blood cells with a variety of cell surface receptors for cytokines. Chemotactic cytokines (chemokines) activate their receptors to evoke the chemotaxis of immune cells in homeostatic migrations or inflammatory conditions towards inflamed tissue or pathogens. Dysregulation of the immune system leading to disorders such as allergies, autoimmune diseases, or cancer requires efficient, fast-acting drugs to minimize the long-term effects of chronic inflammation. Here, we performed structure-based virtual screening (SBVS) assisted by the Keras/TensorFlow neural network (NN) to find novel compound scaffolds acting on three chemokine receptors: CCR2, CCR3, and one CXC receptor, CXCR3. Keras/TensorFlow NN was used here not as a typically used binary classifier but as an efficient multi-class classifier that can discard not only inactive compounds but also low- or medium-activity compounds. Several compounds proposed by SBVS and NN were tested in 100 ns all-atom molecular dynamics simulations to confirm their binding affinity. To improve the basic binding affinity of the compounds, new chemical modifications were proposed. The modified compounds were compared with known antagonists of these three chemokine receptors. Known CXCR3 compounds were among the top predicted compounds; thus, the benefits of using Keras/TensorFlow in drug discovery have been shown in addition to structure-based approaches. Furthermore, we showed that Keras/TensorFlow NN can accurately predict the receptor subtype selectivity of compounds, for which SBVS often fails. We cross-tested chemokine receptor datasets retrieved from ChEMBL and curated datasets for cannabinoid receptors. The NN model trained on the cannabinoid receptor datasets retrieved from ChEMBL was the most accurate in the receptor subtype selectivity prediction. Among NN models trained on the chemokine receptor datasets, the CXCR3 model showed the highest accuracy in differentiating the receptor subtype for a given compound dataset.

CCR3 gene knockout inhibits proliferation, differentiation, and migration of eosinophils in allergic rhinitis model mice

Allergic rhinitis (AR) is characterized by various bothersome clinical symptoms of the nasal mucosa that impaired the quality of daily life. Different chemokine receptors play a crucial role in the recruitment of inflammatory cells in AR. However, the effect of CC chemokine receptor (CCR) 3 on the function of eosinophils (EOS) is still unclear. We investigated the effect of CCR3 on EOS in a murine model of OVA-mediated allergic rhinitis using CCR3-deficient (CCR3-/-) mice. In vitro, bone marrow of CCR3-/- and wild-type (WT) mice were used to investigate the induction and development of EOS. In vivo, Allergic rhinitis was initiated in CCR3-/- and wild-type (WT) mice by passive transfer OVA, followed by detecting the eosinophil infiltration of the nasal mucosa and bone marrow. Then CD34+ progenitor cells in bone marrow and blood were evaluated by IHC analysis. Furthermore, the degranulation proteins of EOS in nasal mucosa, marrow, blood and NALF were determined by IHC, real-time PCR analysis and Western blot. We found that CCR3 gene can regulate the growth and development of primary cultured eosinophils. Knockout CCR3 gene can inhibit the proliferation and degranulation of EOS. The infiltration of eosinophils in the nasal mucosa following OVA-challenged, was significantly higher in WT mice compared with those stimulated with phosphate-buffered saline (PBS) for WT, but that was not seen in similarly treated CCR3-/- mice. Besides, the number of CD34+ progenitor cells in bone marrow and blood were also suppressed in CCR3-/- mice. The degranulation proteins of EOS expressed in nasal mucosa, marrow, blood and NALF were decreased in CCR3-/- AR mice compared with WT-AR mice. And the clinical symptoms were significantly alleviated. The expression of granulation proteins in NALF were not detected in both untreated CCR3-/- mice and WT mice. These results demonstrate a contribution of CCR3 to both the growth, migration, and degranulation of EOS during allergic rhinitis.

C-C Motif Chemokine Receptor 3-Mediated Extracellular Signal-Regulated Kinase 1/2 and p38 Mitogen-Activated Protein Kinase Signaling: Promising Targets for Human Airway Epithelial Mucin 5AC Induction by Eotaxin-2 and Eotaxin-3

INTRODUCTION

Eotaxin-2 and -3 of the C-C chemokine subfamily function as potent chemoattractant factors for eosinophil recruitment and various immune responses in allergic and inflammatory airway diseases. Mucin 5AC (MUC5AC), a major gel-forming secretory mucin, is overexpressed in airway inflammation. However, the association between mucin secretion and eotaxin-2/3 expression in the upper and lower airway epithelial cells has not been fully elucidated. Therefore, in this study, we investigated the effects of eotaxin-2/3 on MUC5AC expression and its potential signaling mediators.

METHODS

We analyzed the effects of eotaxin-2 and -3 on NCI-H292 human airway epithelial cells and primary human nasal epithelial cells (HNEpCs) via reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay, and western blotting. Along with immunoblot analyses with specific inhibitors and small interfering RNA (siRNA), we explored the signaling pathway involved in MUC5AC expression following eotaxin-2/3 treatment.

RESULTS

In HCI-H292 cells, eotaxin-2/3 activated the mRNA expression and protein production of MUC5AC. A specific inhibitor of C-C motif chemokine receptor 3 (CCR3), SB328437, suppressed eotaxin-2/3-induced MUC5AC expression at both the mRNA and protein levels. Eotaxin-2/3 induced the phosphorylation of extracellular signal-regulated kinase (ERK)-1/2 and p38, whereas pretreatment with a CCR3 inhibitor significantly attenuated this effect. Induction of MUC5AC expression with eotaxin-2/3 was decreased by U0126 and SB203580, specific inhibitors of ERK1/2 and p38 mitogen-activated protein kinase (MAPK), respectively. In addition, cell transfection with ERK1/2 and p38 siRNAs inhibited eotaxin-2/3-induced MUC5AC expression. Moreover, specific inhibitors (SB328437, U0126, and SB203580) attenuated eotaxin-2/3-induced MUC5AC expression in HNEpCs.

CONCLUSION

Our results imply that CCR3-mediated ERK1/2 and p38 MAPK are involved in the signal transduction of eotaxin-2/3-induced MUC5AC overexpression.

Strategies for acquisition of resonance assignment spectra of highly dynamic membrane proteins: a GPCR case study

In protein nuclear magnetic resonance (NMR), chemical shift assignment provides a wealth of information. However, acquisition of high-quality solid-state NMR spectra depends on protein-specific dynamics. For membrane proteins, bilayer heterogeneity further complicates this observation. Since the efficiency of cross-polarization transfer is strongly entwined with protein dynamics, optimal temperatures for spectral sensitivity and resolution will depend not only on inherent protein dynamics, but temperature-dependent phase properties of the bilayer environment. We acquired 1-, 2-, and 3D homo- and heteronuclear experiments of the chemokine receptor CCR3 in a 7:3 phosphatidylcholine:cholesterol lipid environment. 1D direct polarization, cross polarization (CP), and T2' experiments indicate sample temperatures below - 25 °C facilitate higher CP enhancement and longer-lived transverse relaxation times. T1rho experiments indicate intermediate timescales are minimized below a sample temperature of - 20 °C. 2D DCP NCA experiments indicated optimal CP efficiency and resolution at a sample temperature of - 30 °C, corroborated by linewidth analysis in 3D NCACX at - 30 °C compared to - 5 °C. This optimal temperature is concluded to be directly related the lipid phase transition, measured to be between - 20 and 15 °C based on rINEPT signal of all-trans and trans-gauche lipid acyl conformations. Our results have critical implications in acquisition of SSNMR membrane protein assignment spectra, as we hypothesize that different lipid compositions with different phase transition properties influence protein dynamics and therefore the optimal acquisition temperature.

Rebalancing liver-infiltrating CCR3+ and CD206+ monocytes improves diet-induced NAFLD

Melatonin has been reported to improve nonalcoholic fatty liver disease (NAFLD), and exploring the underlying mechanisms will be beneficial for better treatment of NAFLD. Choline-deficient high-fat diet (CDHFD)- and methionine/choline-deficient diet (MCD)-fed mice with melatonin intervention exhibit significantly decreased liver steatosis, lobular inflammation, and focal liver necrosis. Single-cell RNA sequencing reveals that melatonin selectively inhibits pro-inflammatory CCR3⁺ monocyte-derived macrophages (MoMFs) and upregulates anti-inflammatory CD206⁺ MoMFs in NAFLD mice. Liver-infiltrating CCR3⁺CD14⁺ MoMFs are also significantly increased in patients with NAFLD. Mechanistically, melatonin receptor-independent BTG2-ATF4 signaling plays a role in the regulation of CCR3⁺ MoMF endoplasmic reticulum stress, survival, and inflammation. In contrast, melatonin upregulates CD206⁺ MoMF survival and polarization via MT1/2 receptors. Melatonin stimulation also regulates human CCR3⁺ MoMF and CD206⁺ MoMF survival and inflammation in vitro. Furthermore, CCR3 depletion antibody monotherapy inhibits liver inflammation and improves NAFLD in mice. Thus, therapies targeting CCR3⁺ MoMFs may have potential benefits in NAFLD treatment.

Chemokine Receptors-Structure-Based Virtual Screening Assisted by Machine Learning

Chemokines modulate the immune response by regulating the migration of immune cells. They are also known to participate in such processes as cell-cell adhesion, allograft rejection, and angiogenesis. Chemokines interact with two different subfamilies of G protein-coupled receptors: conventional chemokine receptors and atypical chemokine receptors. Here, we focused on the former one which has been linked to many inflammatory diseases, including: multiple sclerosis, asthma, nephritis, and rheumatoid arthritis. Available crystal and cryo-EM structures and homology models of six chemokine receptors (CCR1 to CCR6) were described and tested in terms of their usefulness in structure-based drug design. As a result of structure-based virtual screening for CCR2 and CCR3, several new active compounds were proposed. Known inhibitors of CCR1 to CCR6, acquired from ChEMBL, were used as training sets for two machine learning algorithms in ligand-based drug design. Performance of LightGBM was compared with a sequential Keras/TensorFlow model of neural network for these diverse datasets. A combination of structure-based virtual screening with machine learning allowed to propose several active ligands for CCR2 and CCR3 with two distinct compounds predicted as CCR3 actives by all three tested methods: Glide, Keras/TensorFlow NN, and LightGBM. In addition, the performance of these three methods in the prediction of the CCR2/CCR3 receptor subtype selectivity was assessed.

Pharmacological Evidence of the Important Roles of CCR1 and CCR3 and Their Endogenous Ligands CCL2/7/8 in Hypersensitivity Based on a Murine Model of Neuropathic Pain

Neuropathic pain treatment remains a challenging issue because the therapies currently used in the clinic are not sufficiently effective. Moreover, the mechanism of neuropathy is still not entirely understood; however, much evidence indicates that chemokines are important factors in the initial and late phases of neuropathic pain. To date, the roles of CCR1, CCR3 and their endogenous ligands have not been extensively studied; therefore, they have become the subject of our research. In the present comprehensive behavioral and biochemical study, we detected significant time-dependent and long-lasting increases in the mRNA levels of CCR1 and/or CCR3 ligands, such as CCL2/3/4/5/6/7/8/9, in the murine spinal cord after chronic constriction injury of the sciatic nerve, and these increases were accompanied by changes in the levels of microglial/macrophage, astrocyte and neutrophil cell markers. ELISA results suggested that endogenous ligands of CCR1 and CCR3 are involved in the development (CCL2/3/5/7/8/9) and persistence (CCL2/7/8) of neuropathic pain. Moreover, intrathecal injection of CCL2/3/5/7/8/9 confirmed their possible strong influence on mechanical and thermal hypersensitivity development. Importantly, inhibition of CCL2/7/8 production and CCR1 and CCR3 blockade by selective/dual antagonists effectively reduced neuropathic pain-like behavior. The obtained data suggest that CCL2/7/8/CCR1 and CCL7/8/CCR3 signaling are important in the modulation of neuropathic pain in mice and that these chemokines and their receptors may be interesting targets for future investigations.

Bullous pemphigoid-What do we know about the most recent therapies?

INTRODUCTION

Bullous pemphigoid (BP) is the most common subtype of autoimmune blistering diseases that primarily affects the elderly and is classically defined by the presence of IgG and/or complement C3 against the BP180 and BP230 hemidesmosome proteins. However, most recent studies have introduced the role of specific eosinophil receptors and chemokine mediators in the pathogenesis of BP which are helpful in identifying new targets for future treatments.

AREAS COVERED

This review will focus on the involvement of eosinophils in BP, including the processes that lead to their recruitment, activation, and regulation. Subsequently, covering new therapeutic options in relation to the role of eosinophils. Eotaxin enhances the recruitment of eosinophils in BP, with CCR3 chemoreceptor that is expressed on eosinophils being identified as a key binding site for eotaxin-1. The pathogenic role of IgE and IL-4 in BP is corroborated by successful treatments with Omalizumab and Dupilumab, respectively. IL-5, IL-17 and IL-23 inhibitors may be effective given their roles in promoting eosinophilia.

EXPERT OPINION

Further research into inhibitors of eotaxin, IL-4, IL-5, IL-17, IL-23, CCR3, and specific complement factors are warranted as preliminary studies have largely identified success in treating BP with these agents. Learning from novel treatments for other IgG-mediated autoimmune diseases may be beneficial.

Rapid GPR183-mediated recruitment of eosinophils to the lung after Mycobacterium tuberculosis infection

Influx of eosinophils into the lungs is typically associated with type II responses during allergy and fungal and parasitic infections. However, we previously reported that eosinophils accumulate in lung lesions during type I inflammatory responses to Mycobacterium tuberculosis (Mtb) in humans, macaques, and mice, in which they support host resistance. Here we show eosinophils migrate into the lungs of macaques and mice as early as one week after Mtb exposure. In mice this influx is CCR3 independent and instead requires cell-intrinsic expression of the oxysterol receptor GPR183, which is highly expressed on human and macaque eosinophils. Murine eosinophils interact directly with bacilli-laden alveolar macrophages, which upregulate the oxysterol-synthesizing enzyme Ch25h, and eosinophil recruitment is impaired in Ch25h-deficient mice. Our findings show that eosinophils are among the earliest cells from circulation to sense and respond to Mtb infection of alveolar macrophages and reveal a role for GPR183 in the migration of eosinophils into lung tissue.

Eosinophils are usually associated with allergy or type II responses. Here, Bohrer et al. show that eosinophils are rapidly recruited to the lungs after respiratory infection with the intracellular pathogen Mycobacterium tuberculosis through the oxysterol sensor GPR183.

Overexpression of VEGF in the MOPC 315 Plasmacytoma Induces Tumor Immunity in Mice

Vascular endothelial growth factor (VEGF) has important effects on hematopoietic and immune cells. A link between VEGF expression, tumor progression, and metastasis has been established in various solid tumors; however, the impact of VEGF expression by hematopoietic neoplasias remains unclear. Here, we investigated the role of VEGF in plasma cell neoplasia. Overexpression of VEGF in MOPC 315 tumor cells (MOPCSVm) had no effect on their growth in vitro. However, constitutive ectopic expression of VEGF dramatically reduced tumorigenicity of MOPC 315 when implanted subcutaneously into BALB/c mice. Mice implanted with MOPCSVm effectively rejected tumor grafts and showed strong cytotoxic T lymphocyte (CTL) activity against parental MOPC 315 cells. MOPCSVm implants were not rejected in nude mice, suggesting the process is T-cell-dependent. Adoptive transfer of splenocytes from recipients inoculated with MOPCSVm cells conferred immunity to naïve BALB/c mice, and mice surviving inoculation with MOPCSVm rejected the parental MOPC 315 tumor cells following a second inoculation. Immunohistochemical analysis showed that MOPCSVm induced a massive infiltration of CD3+ cells and MHC class II+ cells in vivo. In addition, exogenous VEGF induced the expression of CCR3 in T cells in vitro. Together, these data are the first to demonstrate that overexpression of VEGF in plasmacytoma inhibits tumor growth and enhances T-cell-mediated antitumor immune response.

Expression of the Chemokine Receptor CCR1 in Burkitt Lymphoma Cell Lines Is Linked to the CD10-Negative Cell Phenotype and Co-Expression of the EBV Latent Genes EBNA2, LMP1, and LMP2

Chemokines and their receptors regulate the migration of immune cells and the dissemination of cancer cells. CCR1, CCR2, CCR3, and CCR5 all belong to a single protein homology cluster and respond to the same inflammatory chemokines. We previously reported that CCR1 and CCR2B are induced upon Epstein-Barr virus (EBV) infection of B cells in vitro. EBV is present in almost all cases of endemic Burkitt lymphoma (BL); however, the contribution of EBV in the pathogenesis of the disease is not fully understood. Here, we analyzed the relation of the expression of CCR1, CCR2, CCR3, and CCR5, the EBV DNA load and expression of EBV latent genes in nine EBV-carrying and four EBV-negative BL cell lines. We revealed that CCR1 is expressed at high mRNA and protein levels in two CD10-negative BL cell lines with co-expression of the EBV latent genes EBNA2, LMP1, and LMP2. Low levels of CCR2 transcripts were found in three BL cell lines. CCR3 and CCR5 transcripts were hardly detectable. Our data suggest that in vivo, CCR1 may be involved in the dissemination of BL cells and in the selection of BL cells with restricted EBV gene expression programs.

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.

Cholesterol Is a Dose-Dependent Positive Allosteric Modulator of CCR3 Ligand Affinity and G Protein Coupling

Cholesterol as an allosteric modulator of G protein-coupled receptor (GPCR) function is well documented. This quintessential mammalian lipid facilitates receptor–ligand interactions and multimerization states. Functionally, this introduces a complicated mechanism for the homeostatic modulation of GPCR signaling. Chemokine receptors are Class A GPCRs responsible for immune cell trafficking through the binding of endogenous peptide ligands. CCR3 is a CC motif chemokine receptor expressed by eosinophils and basophils. It traffics these cells by transducing the signal stimulated by the CC motif chemokine primary messengers 11, 24, and 26. These behaviors are close to the human immunoresponse. Thus, CCR3 is implicated in cancer metastasis and inflammatory conditions. However, there is a paucity of experimental evidence linking the functional states of CCR3 to the molecular mechanisms of cholesterol–receptor cooperativity. In this vein, we present a means to combine codon harmonization and a maltose-binding protein fusion tag to produce CCR3 from E. coli. This technique yields ∼2.6 mg of functional GPCR per liter of minimal media. We leveraged this protein production capability to investigate the effects of cholesterol on CCR3 function in vitro. We found that affinity for the endogenous ligand CCL11 increases in a dose-dependent manner with cholesterol concentration in both styrene:maleic acid lipid particles (SMALPs) and proteoliposomes. This heightened receptor activation directly translates to increased signal transduction as measured by the GTPase activity of the bound G-protein α inhibitory subunit 3 (Gα_i3). This work represents a critical step forward in understanding the role of cholesterol-GPCR allostery in regulation of signal transduction.

Platelets Independently Recruit into Asthmatic Lungs and Models of Allergic Inflammation via CCR3

Platelet activation and pulmonary recruitment occur in patients with asthma and in animal models of allergic asthma, in which leukocyte infiltration, airway remodeling, and hyperresponsiveness are suppressed by experimental platelet depletion. These observations suggest the importance of platelets to various characteristics of allergic disease, but the mechanisms of platelet migration and location are not understood. The aim of this study was to assess the mechanism of platelet recruitment to extravascular compartments of lungs from patients with asthma and after allergen challenge in mice sensitized to house dust mite (HDM) extract (contains the DerP1 [Dermatophagoides pteronyssinus extract peptidase 1] allergen); in addition, we assessed the role of chemokines in this process. Lung sections were immunohistochemically stained for CD42b⁺ platelets. Intravital microscopy in allergic mice was used to visualize platelets tagged with an anti-mouse CD49b-PE (phycoerythrin) antibody. Platelet-endothelial interactions were measured in response to HDM (DerP1) exposure in the presence of antagonists to CCR3, CCR4, and CXCR4. Extravascular CD42b⁺ platelets were detected in the epithelium and submucosa in bronchial biopsy specimens taken from subjects with steroid-naive mild asthma. Platelets were significantly raised in the lung parenchyma from patients with fatal asthma compared with postmortem control-lung tissue. Furthermore, in DerP1-sensitized mice, subsequent HDM exposure induced endothelial rolling, endothelial adhesion, and recruitment of platelets into airway walls, compared with sham-sensitized mice, via a CCR3-dependent mechanism in the absence of aggregation or interactions with leukocytes. Localization of singular, nonaggregated platelets occurs in lungs of patients with asthma. In allergic mice, platelet recruitment occurs via recognized vascular adhesive and migratory events, independently of leukocytes via a CCR3-dependent mechanism.

In Silico Identification of Cholesterol Binding Motifs in the Chemokine Receptor CCR3

CC motif chemokine receptor 3 (CCR3) is a Class A G protein-coupled receptor (GPCR) mainly responsible for the cellular trafficking of eosinophils. As such, it plays key roles in inflammatory conditions, such as asthma and arthritis, and the metastasis of many deadly forms of cancer. However, little is known about how CCR3 functionally interacts with its bilayer environment. Here, we investigate cholesterol binding sites in silico through Coarse-Grained Molecular Dynamics (MD) and Pylipid analysis using an extensively validated homology model based on the crystal structure of CCR5. These simulations identified several cholesterol binding sites containing Cholesterol Recognition/Interaction Amino Acid Consensus motif (CRAC) and its inversion CARC motifs in CCR3. One such site, a CARC site in TM1, in conjunction with aliphatic residues in TM7, emerged as a candidate for future investigation based on the cholesterol residency time within the binding pocket. This site forms the core of a cholesterol binding site previously observed in computational studies of CCR2 and CCR5. Most importantly, these cholesterol binding sites are conserved in other chemokine receptors and may provide clues to cholesterol regulation mechanisms in this subfamily of Class A GPCRs.

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.

Eotaxins and Their Receptor as Biomarkers of Colorectal Cancer

Colorectal cancer (CRC) is one of the most common malignancies. Despite the availability of diagnostic tests, an increasing number of new cases is observed. That is why it is very important to search new markers that would show high diagnostic utility. Therefore, we made an attempt to assess the usefulness of eotaxins, as there are few studies that investigate their significance, in patients with CRC. The study included 80 subjects (CRC patients and healthy volunteers). Serum concentrations of all eotaxins were measured using a multiplexing method (Luminex), while CCR3 was measured by immunoenzymatic assay (ELISA). CRP levels were determined by immunoturbidimetry and classical tumor marker levels (CEA and CA 19-9) and were measured using chemiluminescent microparticle immunoassay (CMIA). The highest usefulness among the proteins tested showed CCR3. Its concentrations were significantly higher in the CRC group than in healthy controls. The diagnostic sensitivity, specificity, positive and negative predictive value, and the area under the ROC curve (AUC) of CCR3 were higher than those of CA 19-9. The maximum values for sensitivity, negative predictive value, and AUC were obtained for a combination of CCR3 and CRP. Our findings suggest the potential usefulness of CCR3 in the diagnosis of CRC, especially in combination with CRP or CEA.

CC Chemokine Ligand 7 Derived from Cancer-Stimulated Macrophages Promotes Ovarian Cancer Cell Invasion

In the tumor microenvironment, macrophages have been suggested to be stimulated by tumor cells, becoming tumor-associated macrophages that promote cancer development and progression. We examined the effect of these macrophages on human ovarian cancer cell invasion and found that conditioned medium of macrophages stimulated by ovarian cancer cells (OC-MQs) significantly increased cell invasion. CC chemokine ligand 7 (CCL7) expression and production were significantly higher in OC-MQs than in the control macrophages. Peritoneal macrophages from patients with ovarian cancer showed higher CCL7 expression levels than those from healthy controls. Inhibition of CCL7 using siRNA and neutralizing antibodies reduced the OC-MQ-CM-induced ovarian cancer cell invasion. CC chemokine receptor 3 (CCR3) was highly expressed in human ovarian cancer cells, and a specific inhibitor of this receptor reduced the OC-MQ-CM-induced invasion. Specific signaling and transcription factors were associated with enhanced CCL7 expression in OC-MQs. CCL7-induced invasion required the expression of matrix metalloproteinase 9 via activation of extracellular signal-related kinase signaling in human ovarian cancer cells. These data suggest that tumor-associated macrophages can affect human ovarian cancer metastasis via the CCL7/CCR3 axis.

Development of Anti-Mouse CC Chemokine Receptor 3 Monoclonal Antibodies for Flow Cytometry

CC chemokine receptor 3 (CCR3), also known as CD193, belongs to class A of G protein-coupled receptors and is present in high levels in eosinophils, basophils, and airway epithelial cells. CCR3 is considered the therapeutic target for human immunodeficiency virus (HIV) infections and allergic diseases; therefore, the development of sensitive monoclonal antibodies (mAbs) for CCR3 has been desired. This study aimed to establish a specific and sensitive mAb against mouse CCR3 (mCCR3) useful for flow cytometry analysis by employing the Cell-Based Immunization and Screening (CBIS) method. The generated anti-mCCR3 mAb, C₃Mab-2 (rat IgG_2b, kappa), was found to react with mCCR3-overexpressed Chinese hamster ovary-K1 (CHO/mCCR3) cells, according to flow cytometric analysis. Also, it reacted with P388 (mouse lymphoid neoplasm) or J774-1 (mouse macrophage-like) cells, which express endogenous mCCR3. Taken together, C₃Mab-2, generated by the CBIS method, can be a valuable tool for detecting mCCR3 on the surface of mouse cells.

The Chemokine Receptor CCR3 Is Potentially Involved in the Homing of Prostate Cancer Cells to Bone: Implication of Bone-Marrow Adipocytes

Bone metastasis remains the most frequent and the deadliest complication of prostate cancer (PCa). Mechanisms leading to the homing of tumor cells to bone remain poorly characterized. Role of chemokines in providing navigational cues to migrating cancer cells bearing specific receptors is well established. Bone is an adipocyte-rich organ since 50 to 70% of the adult bone marrow (BM) volume comprise bone marrow adipocytes (BM-Ads), which are likely to produce chemokines within the bone microenvironment. Using in vitro migration assays, we demonstrated that soluble factors released by human primary BM-Ads are able to support the directed migration of PCa cells in a CCR3-dependent manner. In addition, we showed that CCL7, a chemokine previously involved in the CCR3-dependent migration of PCa cells outside of the prostate gland, is released by human BM-Ads. These effects are amplified by obesity and ageing, two clinical conditions known to promote aggressive and metastatic PCa. In human tumors, we found an enrichment of CCR3 in bone metastasis vs. primary tumors at mRNA levels using Oncomine microarray database. In addition, immunohistochemistry experiments demonstrated overexpression of CCR3 in bone versus visceral metastases. These results underline the potential importance of BM-Ads in the bone metastatic process and imply a CCR3/CCL7 axis whose pharmacological interest needs to be evaluated.

[Effect of CCR3 gene on related inflammatory cells in respiratory allergic diseases]

Respiratory allergic disease mainly include asthma and allergic rhinitis.According to their extremely similarpathogenesis and inflammatory pathological changes,asthma and allergic rhinitis,are regarded as the concept of "one airway, one disease". In recent years, The research on the target of allergens in the pathogenesis mechanism is more in-depth, and the CCR3 gene is a major research target. The study found that the CCR3 gene is an important target gene for the development of respiratory allergic diseases such as allergic rhinitis and asthma. The related inflammatory cells are the main cells responding for the downstream cascade triggered by CCR3 activation, which directly or indirectly cause allergic inflammation through itself or its secretions.Therefore, researches on the roles of CCR3 gene and its related inflammatory cells become hot topics in the clinical treatment of respiratory allergic diseases. This paper reviews the current research progress of respiratory allergic diseases on the basis of intensive literature.

Cell-Based Functional IgE Assays Are Superior to Conventional Allergy Tests for Shrimp Allergy Diagnosis

BACKGROUND

The diagnosis of shellfish allergy currently relies on patient history, skin prick test (SPT), and serum specific IgE (sIgE) quantification. These methods lack sufficient diagnostic accuracy, whereas the gold standard of oral food challenges is risky and burdensome. Markers of reactivity and severity of allergic reactions to shellfish will improve clinical care of these patients.

OBJECTIVES

This study compared the diagnostic performance of SPT, sIgE, basophil activation test (BAT), and IgE crosslinking-induced luciferase expression (EXiLE) test for shrimp allergy.

METHODS

Thirty-five subjects with documented history of shrimp allergic reactions were recruited and grouped according to results of double-blind, placebo-controlled food challenge (DBPCFC). In addition to routine diagnostics, BAT (Flow CAST) and EXiLE test with shrimp extract and tropomyosin were performed.

RESULTS

Of 35 subjects, 15 were shrimp allergic with pruritus, urticaria, and itchy mouth on DBPCFC, whereas 20 were tolerant to shrimp. Tropomyosin only accounted for 53.3% of sensitization among subjects with challenge-proven shrimp allergy. BAT using shrimp extract as stimulant showed the highest area under curve value (0.88), Youden Index (0.81), likelihood ratio (14.73), odds ratio (104), and variable importance (4.27) when compared with other assays and tropomyosin diagnosis. Results of BAT significantly correlated with those of EXiLE (r = 0.664, P < .0001).

CONCLUSIONS

BAT is a more accurate diagnostic marker for shrimp allergy than SPT and shrimp sIgE, whereas the EXiLE test based on an IgE crosslinking assay is a good alternative to BAT. Tropomyosin may not be the most important shrimp allergen in Chinese, which warrants further investigation to search for other major allergens and diagnostic markers.

miR-30a-3p participates in the development of asthma by targeting CCR3

This study aimed to investigate the role and relevant mechanism of miR-30a-3p action in asthma. The results of this study revealed that the expression levels of miR-30a-3p were significantly decreased in the peripheral blood of asthmatic patients. In addition, we found that the CC chemokine receptor (CCR3) was a target of miR-30a-3p. Subsequently, an asthma mouse model was established using ovalbumin (OVA). The results showed that the expression of miR-30a-3p and CCR3 was downregulated and upregulated, respectively, in the peripheral blood of asthmatic mice. Enzyme-linked immunosorbent assay (ELISA) in asthmatic mouse serum demonstrated that miR-30a-3p mimic treatment significantly decreased the secretion of OVA-specific IgE, eotaxin-1, interleukin (IL)-5, and IL-4. These results suggested that miR-30a-3p inhibited CCR3 signaling pathway and relieved the inflammatory response against asthma in vivo. Eosinophils have also been implicated in the asthmatic inflammatory response. Therefore, the in vitro effects of miR-30a-3p on eosinophil activity were determined. Findings suggested that miR-30a-3p mimic significantly reduced eosinophil viability and migration and induced apoptosis. In addition, CCR3 and eotaxin-1 downregulation were observed. The aforementioned results were significantly reversed following CCR3 overexpression. This study suggested that miR-30a-3p was involved in asthma by regulating eosinophil activity and targeting CCR3.

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.

Eotaxins and Their Receptor in Colorectal Cancer-A Literature Review

Colorectal cancer (CRC) is one of the most common malignancies in the world, with a global incidence of almost 2 million new cases every year. Despite the availability of many diagnostic tests, including laboratory tests and molecular diagnostics, an increasing number of new cases is observed. Thus, it is very important to search new markers that would show high diagnostic sensitivity and specificity in the detection of colorectal cancer in early stages of the disease. Eotaxins are proteins that belong to the cytokine group-small molecules with a variety of applications. Their main role is the activation of basophils and eosinophils involved in inflammatory processes. Therefore, we performed an extensive search of the literature pertaining to our investigation via the MEDLINE/PubMed database. On the basis of available literature, we can assume that eotaxins accumulate in cancer cells in the course of CRC. This leads to a decrease in the chemotaxis of eosinophils, which are effector immune cells with anti-tumor activity. This may explain a decrease in their number as a defense mechanism of cancer cells against their destruction and may be useful when attempting anti-tumor therapy with the use of chemokines.

Piperine Ameliorates Trimellitic Anhydride-Induced Atopic Dermatitis-Like Symptoms by Suppressing Th2-Mediated Immune Responses via Inhibition of STAT6 Phosphorylation

Atopic dermatitis (AD) is a common inflammatory skin disease predominately related to Type 2 helper T (Th2) immune responses. In this study, we investigated whether piperine is able to improve AD symptoms using a trimellitic anhydride (TMA)-induced AD-like mouse model. Topical treatment with piperine reduced ear swelling (ear thickness and epidermal thickness) induced by TMA exposure. Furthermore, piperine inhibited pro-inflammatory cytokines such as TNF-α and IL-1β in mouse ears, compared with the TMA-induced AD group. In measuring allergic immune responses in draining lymph nodes (dLNs), we found that IL-4 secretion, GATA3 mRNA level, and STAT6 phosphorylation were suppressed by piperine treatment. In an ex vivo study, piperine also inhibited the phosphorylation of STAT6 on the CD4⁺ T cells isolated from splenocytes of BALB/c mice, and piperine suppressed IL-4-induced CCL26 mRNA expression and STAT6 phosphorylation in human keratinocytes resulting in the inhibition of infiltration of CCR3⁺ cells into inflammatory lesions. These results demonstrate that piperine could ameliorate AD symptoms through suppression of Th2-mediated immune responses, including the STAT6/GATA3/IL-4 signaling pathway. Therefore, we suggest that piperine is an excellent candidate as an inhibitor of STAT6 and may help to improve AD symptoms.

Function of CCL5 in maternal-fetal interface of pig during early pregnancy

Chemokines refer to chemoattractant cytokines, which have crucial functions in inflammation and immune responses in multiple cellular processes. In the present study, we described the potential role of porcine CCL5 in embryo implantation and fetal-maternal environment during early pregnancy. We first carried out phylogenetic analysis of porcine CCL5, and analyzed the cell specific localization of CCL5 and its receptor CCR3 in a kinetic approach within porcine estrous cycles and early gestation stage. In addition, CCL5 stimulated porcine uterine luminal epithelial (pLE) and porcine trophectoderm (pTr) cell proliferations, and cell cycle progressions via AKT and MAPK intracellular signaling tractions. Furthermore, CCL5 attenuated tunicamycin-induced endoplasmic reticulum (ER) stress signaling, and lipopolysaccharides-triggered inflammatory responses in pLE and pTr cells. Taken together, our study showed that CCL5 is involved in the placental development or promotes the placental development.

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.

The small molecular CCR3 antagonist YM344031 attenuates neurodegenerative pathologies and improves learning and memory performance in a mouse model of Alzheimer's disease

The chemokine C-C receptor 3 (CCR3) plays a role in the pathogenesis of Alzheimer's disease (AD). Based on our previous observations that deletion of CCR3 prevented neurodegenerative pathologies in amyloid precursor protein/presenilin 1 (APP/PS1) double-transgenic mice, we hypothesize that CCR3 antagonists may provide therapeutic benefits to AD. To this end, we examined the effect of the brain-penetrable CCR3 antagonist, YM344031, on AD-related pathologies in APP/PS1 double transgenic mice. Treatment of 10-month-old APP/PS1 double-transgenic mice with YM344031 (50 mg/kg, b.i.d.) for two months resulted in dramatic decreases in β-amyloid deposition, tau hyperphosphorylation and synaptic loss in the forebrain, significant attenuation of microgliosis and astrogliosis, and marked improvement of spatial learning and memory performance compared with the vehicle-treated mice. These results support CCR3 antagonism as a potential therapeutic strategy for AD.

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.

Leptin Elicits LTC4 Synthesis by Eosinophils Mediated by Sequential Two-Step Autocrine Activation of CCR3 and PGD2 Receptors

Leptin is a cytokine, produced mainly by mature adipocytes, that regulates the central nervous system, mainly to suppress appetite and stimulate energy expenditure. Leptin also regulates the immune response by controlling activation of immunomodulatory cells, including eosinophils. While emerging as immune regulatory cells with roles in adipose tissue homeostasis, eosinophils have a well-established ability to synthesize pro-inflammatory molecules such as lipid mediators, a key event in several inflammatory pathologies. Here, we investigated the impact and mechanisms involved in leptin-driven activation of eicosanoid-synthesizing machinery within eosinophils. Direct in vitro activation of human or mouse eosinophils with leptin elicited synthesis of lipoxygenase as well as cyclooxygenase products. Displaying selectivity, leptin triggered synthesis of LTC₄ and PGD₂, but not PGE₂, in parallel to dose-dependent induction of lipid body/lipid droplets biogenesis. While dependent on PI3K activation, leptin-driven eosinophil activation was also sensitive to pertussis toxin, indicating the involvement of G-protein coupled receptors on leptin effects. Leptin-induced lipid body-driven LTC₄ synthesis appeared to be mediated through autocrine activation of G-coupled CCR3 receptors by eosinophil-derived CCL5, inasmuch as leptin was able to trigger rapid CCL5 secretion, and neutralizing anti-RANTES or anti-CCR3 antibodies blocked lipid body assembly and LTC₄ synthesis induced by leptin. Remarkably, autocrine activation of PGD₂ G-coupled receptors DP1 and DP2 also contributes to leptin-elicited lipid body-driven LTC₄ synthesis by eosinophils in a PGD₂-dependent fashion. Blockade of leptin-induced PGD₂ autocrine/paracrine activity by a specific synthesis inhibitor or DP1 and DP2 receptor antagonists, inhibited both lipid body biogenesis and LTC₄ synthesis induced by leptin stimulation within eosinophils. In addition, CCL5-driven CCR3 activation appears to precede PGD₂ receptor activation within eosinophils, since neutralizing anti-CCL5 or anti-CCR3 antibodies inhibited leptin-induced PGD₂ secretion, while it failed to alter PGD₂-induced LTC₄ synthesis. Altogether, sequential activation of CCR3 and then PGD₂ receptors by autocrine ligands in response to leptin stimulation of eosinophils culminates with eosinophil activation, characterized here by assembly of lipidic cytoplasmic platforms synthesis and secretion of the pleiotropic lipid mediators, PGD₂, and LTC₄.

The basophil activation test differentiates between patients with alpha-gal syndrome and asymptomatic alpha-gal sensitization

BACKGROUND

Galactose-alpha-1,3-galactose (alpha-gal) syndrome is characterized by the presence of serum specific IgE antibodies to alpha-gal and delayed type I allergic reactions to the carbohydrate alpha-gal after consumption of mammalian (red) meat products and drugs of mammalian origin. Diagnostics currently rely on patient history, skin tests, determination of serum specific IgE antibodies, and oral food or drug challenges.

OBJECTIVE

We sought to assess the utility of different basophil parameters (basophil reactivity and sensitivity, the ratio of the percentage of CD63⁺ basophils induced by the alpha-gal-containing allergen to the percentage of CD63⁺ basophils after stimulation with anti-FcεRI antibody [%CD63⁺/anti-FcεRI], and area under the dose-response curve [AUC]) as biomarkers for the clinical outcome of patients with alpha-gal syndrome compared with subjects with asymptomatic alpha-gal sensitization.

METHODS

In addition to routine diagnostics, a basophil activation test (Flow CAST) with different concentrations of alpha-gal-containing allergens (eg, commercially available alpha-gal-carrying proteins and pork kidney extracts) was performed in 21 patients with alpha-gal syndrome, 12 alpha-gal-sensitized subjects, and 18 control subjects.

RESULTS

Alpha-gal-containing allergens induced strong basophil activation in a dose-dependent manner in patients. Basophil reactivity at distinct allergen concentrations, the %CD63⁺/anti-FcεRI ratio across most allergen concentrations, the AUC of dose-response curves, and basophil allergen threshold sensitivity (CD-sens) with pork kidney extract were significantly higher in patients with alpha-gal syndrome compared with those in sensitized subjects. All parameters were negative in control subjects.

CONCLUSION

The basophil activation test should be considered as an additional diagnostic test before performing time-consuming and potentially risky oral provocation tests. The %CD63⁺/anti-FcεRI ratio for all allergens and AUCs for pork kidney were the best parameters for distinguishing patients with alpha-gal syndrome from subjects with asymptomatic alpha-gal sensitization.

Mesenchymal stem cells up-regulate the invasive potential of prostate cancer cells via the eotaxin-3/CCR3 axis

This study aimed to clarify the role of mesenchymal stem cells (MSCs) as a component of the cancer microenvironment. We investigated the homing-related chemokine expression levels of MSCs treated with a prostate cancer cell line (PC-3) -conditioned medium. Among several homing chemokines, an antibody array revealed that expression of eotaxin-3 (but not eotxin-1 and -2) was highly enhanced in MSCs treated with PC-3-conditioned medium. A gene expression array showed significantly increased expression of CCR3, a receptor of eotaxin-3, in PC-3. In a matrigel invasion assay, interferon-gamma, a specific inhibitor of eotaxin-related homing, significantly reduced the transmigration of PC-3 cells, under co-cultured condition with MSCs, in a dose-dependent manner (P < 0.05). Consistent with these results, anti-CCR3 antibody successfully reduced PC-3 migration under the co-cultured condition. These findings suggest that MSCs to modulation of the invasive potential of prostate cancer cells via the eotaxin-3/CCR3 axis.

Phenotyping CD4+ hTh2 Cells by Flow Cytometry: Simultaneous Detection of Transcription Factors, Secreted Cytokines, and Surface Markers

Flow cytometry is a powerful technique that allows simultaneous detection of multiple markers on a specific cell population. This method is virtually unlimited as long as the specimen of interest can be put into a single-cell suspension for staining and subsequent analysis by the flow cytometer. Most investigators using this methodology are doing so because their cell population is rare in frequency and requires multiple markers to characterize their population of interest; thus standard methods such as Western blot and IHC are unsuitable due to limitations in cell number and the number of markers available. Most investigators using this method are using 6-14 parameters to study their cell populations of interest: however, using a large number of fluorochrome-labeled antibodies is hampered by the fact that suboptimal fluorochromes must be used, and that high and low cell density markers must be chosen with care. This is further complicated when the cell markers of interest are cytokines, transcription factors, surface markers, and/or phosphorylated proteins, each potentially requiring a specialized buffer system for optimal detection of the antibody of interest. This chapter focuses on optimizing flow cytometry staining methods for simultaneous detection of surface markers, transcription factors, secreted cytokines, and phosphorylated antibodies in a single stain on CD4+ human Th2 cells.

Expression and prognostic significance of CCL11/CCR3 in glioblastoma

Glioblastoma (GBM) is the most lethal primary nervous system cancer, but due to its rarity and complexity, its pathogenesis is poorly understood. To identify potential tumorigenic factors in GBM, we screened antibody-based cytokine arrays and found that CCL11 was upregulated. We then demonstrated in vitro that both CCL11 and its receptor, CCR3, were overexpressed and promoted the proliferation, migration and invasion of cancer cells. To examine the clinical significance of CCL11/CCR3, 458 GBM samples were divided into a training cohort with 225 cases and a test cohort containing 233 cases. In the training set, immunohistochemical analysis showed overexpression of CCL11 and CCR3 were correlated with unfavorable overall survival (OS). We further developed a prognostic classifier combining CCL11 and CCR3 expression and Karnofsky performance status (KPS) for predicting one-year survival in GBM patients. Receiver operating characteristic (ROC) analysis demonstrated that this predictor achieved 90.7% sensitivity and 73.4% specificity. These results were validated with the test sample set. Our findings suggest that CCL11-CCR3 binding is involved in the progression of GBM and may prompt a novel therapeutic approach. In addition, CCL11 and CCR3 expression, combined with KPS, may be used as an accurate predictor of one-year survival in GBM patients.

Crosstalk between CCL7 and CCR3 promotes metastasis of colon cancer cells via ERK-JNK signaling pathways

Chemokine ligand 7 (CCL7) enhances cancer progression and metastasis via epithelial-mesenchymal transition (EMT). However, little is known about the molecular mechanism of CCL7-induced EMT signaling cascade in colon cancer. Thus, the objective of this study was to investigate CCL7-induced EMT signaling pathway and its role in the progression and metastasis of colon cancer. To demonstrate the effect of CCL7 on EMT induction, HCT116 and HT29 cells overexpressing CCL7 were generated. CCL7-induced EMT and its downstream signaling pathway were evaluated by both in vitro and in vivo experiments. In in vitro studies, CCL7 was found to interplay with CC chemokine receptor 3 (CCR3), resulting in enhanced cellular proliferation, invasion, and migration via ERK and JNK signaling pathway. To validate these findings, we established ectopic and orthotopic mouse models injected with CCL7-overexpressed cells. In ectopic mouse models, we observed that CCL7-overexpressed cells grew significantly faster than control cells. In orthotopic mouse models, we found that liver and lung metastasis developed only in mice injected with CCL7-overexpressed cells. This study is the first one focusing on the EMT cascade via CCL7-CCR3-ERK-JNK signaling axis in colon cancer. Our novel findings will improve our understanding on the mechanism of metastatic process and provide potential therapeutic strategies for preventing metastasis in colon cancer.

[Effect of CCR3 gene knockout on eosinophils in mice]

Objective:To investigate the effect of CCR3 gene knockout on the proliferation, maturation and apoptosis of eosinophils (EOS) in mice. Method:Bone marrow cells from CCR3 gene knockout mice (experimental group) and wild-type mice (control group) were cultured in vitro and induced differentiation into mature EOS. EOS proliferation was observed by cell counting.Expression of degranulation protein mRNA was detected by qRT-PCR. EOS apoptosis was detected by Annexin V-FITC/PI double staining method. Result:①The number of cells on the 0-14 day of EOS cultured in vitro showed that the number of cells in the experimental group was less than that in the control group at tenth, twelfth, fourteenth days, and the proliferation was slower, the difference was statistically significant (P<0.01). ②The test results of EOS cells apoptosis showed that, under the condition of containing 10 ng/ml IL-5 or no IL-5, the apoptosis rate of EOS cells in experimental group was higher than that in normal control group, the difference between both groups was statistically significant (P<0.01). ③The expression results of ECP, EPO, MBP mRNA in EOS showed that the expression levels of ECP, EPO, MBP mRNA in the experimental group compared with the normal control group were reduced in varying degrees, the difference between both groups was statistically significant (P<0.05). Conclusion:Knockout CCR3 gene can inhibit the proliferation and maturation of EOS and promote its apoptosis, which provides a theoretical basis for CCR3 as a target gene to treat allergic rhinitis.

Intratumoral expression of CCR3 in breast cancer is associated with improved relapse-free survival in luminal-like disease

PURPOSE

The association chemokine receptor CCR3 with breast cancer subtypes and relapse-free survival is unknown.

RESULTS

The overall expression (either intratumoral or peritumoral) of CCR3 was not associated with tumor size, lymph node status, age, and subtype. When we confined the analysis in samples without peritumoral stromal CCR3 expression, intratumoral expression of CCR3 was associated with breast cancer subtype (P=0.04). Tumors with high expression of CCR3 were more likely to be luminal-like rather than TNBC or HER2-enriched cancers. Moreover, high mRNA expression of CCR3 was related with improved relapse-free survival in luminal-A/B (P<0.001). The subsequent sensitivity analysis using the systemically untreated patients confirmed that higher mRNA expression of CCR3 was a robust prognostic factor for luminal-A (P=0.0025) and luminal-B (P=0.088), but not for HER2-enriched (P=0.21) and TNBC (P=0.86). In the independent cohort, the positive association between increased expression of CCR3 and improved distant relapse-free survival was also observed.

METHODS

We determined the expression level of CCR3 in 150 cases with breast cancer by using immunohistochemistry (IHC) assay, for both intratumoral and peritumoral stroma, and investigated the effect of CCR3 expression on relapse-free survival according to subtype using cases from publicly available datasets, in the whole group (N=3557) and in the patients without adjuvant systemic treatment (N=1005), respectively. Moreover, the survival outcomes were validated in another independent cohort including 508 breast cancer patients treated with neoadjuvant chemotherapy.

CONCLUSIONS

Our data indicate that intratumoral expression of CCR3 in breast cancer is associated with improved relapse-free survival in patients with luminal-like disease.

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.

Suppression of Retinal Neovascularization by Anti-CCR3 Treatment in an Oxygen-Induced Retinopathy Model in Mice

PURPOSE

To investigate the association between retinal neovascularization and the CC chemokine receptor-3 (CCR3) in a mouse model of oxygen-induced retinopathy (OIR).

METHODS

An OIR model in C57BL/6J mice was used as a retinal neovascularization model. An enzyme-linked immunosorbent assay was performed to evaluate the chronological change in vascular endothelial growth factor A (VEGF-A) and eotaxin expressions. CCR3 and VEGF subtype expression in the retina was examined using real-time RT-PCR, and CCR3, eotaxin, VEGF-A, and CD31 expression was examined immunohistochemically. A CCR3 neutralizing antibody (Ab) was injected into the vitreous humor on both postnatal days 12 (P12) and 14 (P14). Retinal neovascularizations were quantified by measurement of the percentages of neovascular area.

RESULTS

The mean eotaxin and VEGF-A protein level was significantly downregulated at P10 and P12 and was significantly upregulated at P14 and P17 (p < 0.05). CCR3 mRNA expression was significantly upregulated at P12 (p < 0.05). VEGF164 mRNA expression was significantly upregulated at P14 (p < 0.05). The areas of vaso-obliteration and neovascularization were significantly suppressed in anti-CCR3 Ab-treated eyes (p < 0.05). Anti-CCR3 Ab treatment suppressed VEGF and eotaxin but not monocyte chemoattractant protein-1. And VEGF 164 mRNA but not VEGF120 mRNA was suppressed by anti-CCR3 Ab treatment.

CONCLUSIONS

The present data suggest that anti-CCR3 treatment can suppress retinal neovascularization. Anti-CCR3 treatment may have potential as a new therapy for retinopathies with retinal neovascularization such as diabetic retinopathy and retinopathy of prematurity.

CCL11 promotes angiogenic activity by activating the PI3K/Akt pathway in HUVECs

CCR3, the receptor for CCL11, is expressed on the surface of immune cells and even on non-immune cells. CCL11-CCR3 interactions can promote cell migration and proliferation. In this study, we investigated the effect of CCL11 on angiogenesis in HUVECs and also examined the molecular mechanisms of this process. We found that CCL11 induced mRNA transcription and protein expression of CCR3 in HUVECs. Moreover, the scratch wound healing assay and MTS proliferation assay both demonstrated that CCL11 promotes endothelial cell migration and induces weak proliferation. CCL11 directly induced microvessel sprouting from the rat aortic ring; these effects occurred earlier and to a greater extent than with VEGF stimulation. Furthermore, CCL11-induced phosphorylation of Akt was abolished by PI3K inhibitors. siRNA-mediated knockdown of CCR3 led to a significant reduction of PI3K phosphorylation. However, the phosphorylation levels of ERK1/2 were not changed, even after CCL11 treatment. Cumulatively, our data suggest that the CCL11-CCR3 interaction mainly activates PI3K/Akt signal transduction pathway in HUVECs.

CCR3 Monoclonal Antibody Inhibits Eosinophilic Inflammation and Mucosal Injury in a Mouse Model of Eosinophilic Gastroenteritis

Purpose

Although the role of eosinophils in eosinophilic gastroenteritis (EGE) is not fully understood, they are believed to be a principal effector cell. Previous studies have demonstrated that eotaxin and its specific receptor, cysteine-cysteine chemokine receptor-3 (CCR3), play a central role in eosinophil trafficking into the gastrointestinal (GI) tract. Thus, we examined the targeting of CCR3 as a potential therapeutic intervention for EGE in a mouse model.

Methods

Eight- to 10-week-old BALB/c mice were intraperitoneally sensitized and intragastrically challenged with ovalbumin (OVA). Different groups of mice were administered either an anti-CCR3 antibody or a control IgG by intraperitoneal injection 1 hour before each OVA challenge. Eosinophilic inflammation in the intestinal mucosa, mucosal injury, and severity of diarrhea were compared between different groups at 1 hour after final OVA challenge.

Results

Anti-CCR3 antibody reduced the number of eosinophils in peripheral blood and intestinal mucosa, but not in bone marrow. This reduction was associated with restoration of reduced villous crypt ratio, increased intestinal epithelial cell proliferation, and weight loss induced by OVA challenge. However, Anti-CCR3 antibody had no effect on the level of OVA specific immunoglobulin E (IgE) and the expression of critical chemokines or cytokines in eosinophil trafficking into the GI tract, such as eotaxin-1, interleukin (IL)-5, and IL-13.

Conclusions

Anti-CCR3 antibody significantly reduced the severity of eosinophilic inflammation, mucosal injury, and diarrhea in a mouse model of food allergen-induced GI eosinophilic inflammation. CCR3 may be a novel therapeutic target for treatment of EGE and other GI eosinophil-mediated diseases.

Immunohistochemical differentiation of eosinophilic esophageal myositis from eosinophilic esophagitis

BACKGROUND AND AIM

Eosinophilic esophagitis (EoE) is a Th2-mediated allergic disease of the esophageal epithelium, associated with antigen. We previously reported a case series for eosinophilic esophageal myositis (EoEM)-a novel eosinophilic gastrointestinal disorder defined as eosinophilic infiltration localized in the esophageal muscle layer-and diagnosed it by peroral endoscopic muscle biopsy. Here, we investigated the immunopathology of EoEM to differentiate it from EoE.

METHODS

Histological analysis was performed for three cases of EoEM and EoE, respectively. The results were compared with those of two control samples (non-eosinophilic gastrointestinal disorder full-layer esophagus). Using immunofluorescence, we analyzed the expression of the chemokine receptor CCR3 and its ligands eotaxin-1 and eotaxin-3 to investigate the eosinophilic reaction. Additionally, we determined the expression patterns of desmoglein-1 in the esophageal epithelium, which shows dysregulated expression in EoE.

RESULTS

Eosinophil infiltration was observed in the muscle layer (maximum number, 30, 36, 73/high-power field) and the epithelium (50, 44, 40/high-power field) for EoEM and EoE, respectively. In EoE esophageal epithelium, the number of eotaxin-3-positive epithelial cells was significantly increased together with CCR3-positive infiltrating cells. However, in EoEM, a number of eotaxin-1-positive and eotaxin-3-positive myocytes and vascular endothelial cells were increased in the esophageal muscle layer. A significant loss of desmoglein-1 expression was only observed in EoE, not in EoEM.

CONCLUSIONS

Eotaxin-1 and eotaxin-3 expression on the smooth muscle and vessels plays a role in the pathogenesis of EoEM, while EoE shows an epithelial eotaxin-3-dominant immunoreaction. Thus, the EoEM immunological pattern displays clear differences from that of EoE.

Catalpol alleviates ovalbumin-induced asthma in mice: Reduced eosinophil infiltration in the lung

BACKGROUND

Radix Rehmanniae Preparata is a traditional Chinese herbal medicine used to treat asthma, and catalpol is one of the main active ingredients in this herb. In the present study, the effects of catalpol on asthma and the underlying mechanism were explored.

METHODS

Mice with ovalbumin (OVA)-induced asthma were given 5 or 10mg/kg catalpol from Day 15 to Day 28 (intraperitoneal injection). Histopathologic changes were detected by Hematoxylin and Eosin staining and Periodic Acid Schiff staining. The levels of IgE, interleukin (IL)-4, IL-5 and eotaxin were measured by ELISA. The numbers of lymphocytes, monocytes, basophils and eosinophils in the bronchoalveolar lavage fluid were determined by Wright-Giemsa staining. The expression and distribution of eotaxin and C-C chemokine receptor 3 (CCR3) were detected by immunohistochemistry and immunofluorescence. The expression of interleukin-5 receptor α (IL-5Rα) was detected by Western blot assay.

RESULTS

Catalpol inhibited OVA-induced inflammation and IgE secretion in the lung. OVA-induced type 2 inflammation was suppressed by catalpol as evidenced by decreased levels of IL-4 and IL-5. Moreover, catalpol inhibited the aberrant eosinophil infiltration in the lungs, and also suppressed OVA-induced elevation of eosinophil chemokine eotaxin and its receptor CCR3. In addition, IL-5Rα expression in the bone marrow cells derived from catalpol-treated asthmatic mice was lower than that from the untreated asthmatic mice.

CONCLUSION

Our study demonstrated that catalpol attenuated OVA-induced asthma and inhibit the infiltration of inflammatory cells, especially eosinophils, into the lung. This study suggests that catalpol may become a promising drug for the treatment of asthma.

Targeting CCR3 to Reduce Amyloid-β Production, Tau Hyperphosphorylation, and Synaptic Loss in a Mouse Model of Alzheimer's Disease

The majority of Alzheimer's disease (AD) patients have a late onset, and chronic neuroinflammation, characterized by glial activation and secretion of pro-inflammatory cytokines and chemokines, plays a role in the pathogenesis of AD. The chemokine CCL11 has been shown to be a causative factor of cognitive decline in the process of aging, but little is known whether it is involved in the pathogenesis of AD. In the present study, we showed that CCR3, the receptor for CCL11, was expressed by hippocampal neurons and treatment of primary hippocampal neuronal cultures (14 days in vitro) with CCL11 resulted in activation of cyclin-dependent kinase 5 and glycogen synthase kinase-3β, associated with elevated tau phosphorylation at multiple sites. CCL11 treatment also induced the production of Aβ and dendritic spine loss in the hippocampal neuronal cultures. All these effects were blocked by the CCR3 specific antagonist, GW766994. An age-dependent increase in CCL11, predominantly expressed by the activated microglia, was observed in the cerebrospinal fluid of both APP/PS1 double transgenic mice and wild-type (WT) littermates, with a markedly higher level in APP/PS1 double transgenic mice than that in WT littermates. Deletion of CCR3 in APP/PS1 double transgenic mice significantly reduced the phosphorylation of CDK5 and GSK3β, tau hyperphosphorylation, Aβ deposition, microgliosis, astrogliosis, synaptic loss, and spatial learning and memory deficits. Thus, the age-related increase in CCL11 may be a risk factor of AD, and antagonizing CCR3 may bring therapeutic benefits to AD.

Dietary treatment modulates mast cell phenotype, density, and activity in adult eosinophilic oesophagitis

BACKGROUND

Mast cells (MCs) are abundant in the inflammatory infiltrate in eosinophilic oesophagitis (EoE), but decrease with disease remission. However, their phenotype, role in the pathophysiology of the disease, and modulation after effective dietary therapy are still unclear.

OBJECTIVE

To define the phenotype of oesophageal MCs, their modulation through dietary therapy, and their association with clinical manifestations of EoE.

METHODS

Oesophageal mucosal samples from 10 adult patients with EoE obtained before and after effective six-food elimination diet (SFED) therapy, as well as from 10 control subjects were analysed. Eosinophil and MC density were quantified. Gene expression of chemoattractants for eosinophils (CCL11, CCL24, and CCL26), MCs (SCF), and their receptors (CCR3 and SCFR, respectively) were assessed by means of qPCR. Gene and protein expression of specific MC proteases (CPA3, CMA, and TPSB2) were evaluated with qPCR and immunofluorescence. Clinical manifestations and atopic background were recorded.

RESULTS

MC density was significantly increased in EoE compared with controls, decreasing after dietary treatment (18.6 to 1.44 cells/hpf, respectively; P < 0.001). The MCTC subtype predominated in the oesophageal mucosa (90%) in both patients with EoE and controls. Gene expression of MC-related proteases, eotaxins, and SCF were up-regulated in patients with EoE, but significantly decreased after therapy, regardless of atopic background. Epithelial peaks of MCs and eosinophils were significantly associated (ρ = 0.80) in EoE and correlated with the symptom score (ρ = 0.78). Gene expression of MC proteases and eotaxins also correlated with the symptom score (P < 0.05).

CONCLUSIONS AND CLINICAL RELEVANCE

MC and its proteases seem to play a relevant role in the pathophysiology and symptoms of EoE, which can be reversed after effective dietary treatment.