Proinflammatory proteases liberate a discrete high-affinity functional FPRL1 (CCR12) ligand from CCL23

Multi‑faceted roles of cathepsins in ischemia reperfusion injury (Review)

Cathepsins are one of the most abundant proteases within the lysosomes with diverse physiological effects ranging from immune responses, cell death and intracellular protein degradation. Cathepsins are involved in extracellular and systemic functions such as systemic inflammation and extracellular matrix degradation. Ischemia reperfusion (IR) injury is responsible for numerous diseases including myocardial infarction, acute kidney injury, stroke and acute graft failure after transplant surgery. Inflammation plays a major role in the reperfusion phase of IR injury and previous research has shown that cathepsins are key mediators of the inflammation cascade as well as apoptosis. Taken together, cathepsins modulation could provide potential therapeutic approaches to attenuate IR injury. The present review summarized the current understanding of various cathepsin subtypes, their major physiologic functions, their roles in multi‑organ IR injury and detailed selective cathepsin inhibitors with therapeutic potential.

ccr7 affects both morphogenesis and differentiation during early Xenopus embryogenesis

Chemokines play important roles in early embryogenesis, including morphogenesis and cell differentiation, before the immune system is established. We characterized Xenopus laevis CC-type chemokine receptor 7 S (ccr7.S) to clarify its role during early development. ccr7 transcripts were detected ubiquitously in early embryos. Dorsal overexpression of ccr7.S inhibited gastrulation, and ccr7.S mRNA-injected embryos had short axes and widely opened neural folds. Because the Keller sandwich explants of the injected embryos elongated well, ccr7.S might affect cell migration, but not convergent extension movements. Ventral ccr7.S overexpression induced secondary axes and chrd.1 upregulation in gastrula-stage embryos. Animal cap assays showed increased expression of neural and cement gland marker genes at later stages. Ccr7.S knockdown reduced chrd.1 expression and inhibited gastrulation at the dorsal side. Our findings suggest that ccr7.S plays important roles in morphogenetic movement and cell differentiation.

CC Chemokines in a Tumor: A Review of Pro-Cancer and Anti-Cancer Properties of the Ligands of Receptors CCR1, CCR2, CCR3, and CCR4

CC chemokines, a subfamily of 27 chemotactic cytokines, are a component of intercellular communication, which is crucial for the functioning of the tumor microenvironment. Although many individual chemokines have been well researched, there has been no comprehensive review presenting the role of all known human CC chemokines in the hallmarks of cancer, and this paper aims at filling this gap. The first part of this review discusses the importance of CCL1, CCL3, CCL4, CCL5, CCL18, CCL19, CCL20, CCL21, CCL25, CCL27, and CCL28 in cancer. Here, we discuss the significance of CCL2 (MCP-1), CCL7, CCL8, CCL11, CCL13, CCL14, CCL15, CCL16, CCL17, CCL22, CCL23, CCL24, and CCL26. The presentation of each chemokine includes its physiological function and then the role in tumor, including proliferation, drug resistance, migration, invasion, and organ-specific metastasis of tumor cells, as well as the effects on angiogenesis and lymphangiogenesis. We also discuss the effects of each CC chemokine on the recruitment of cancer-associated cells to the tumor niche (eosinophils, myeloid-derived suppressor cells (MDSC), tumor-associated macrophages (TAM), tumor-associated neutrophils (TAN), regulatory T cells (T_reg)). On the other hand, we also present the anti-cancer properties of CC chemokines, consisting in the recruitment of tumor-infiltrating lymphocytes (TIL).

Expression and subcellular analyses of CCR8a/b genes with the identification of response to SGIV viral infect in orange-spotted grouper (Epinephelus coioides)

Chemokine receptors are a superfamily of seven transmembrane domain G-coupled receptors, and they play important roles in immune surveillance, inflammation, and development. Recently, nine CC chemokine receptors (CCRs) were identified and cloned from orange-spotted grouper (Epinephelus coioides) and annotated by phylogenetic and syntenic analyses. We detected mRNA transcripts for CCRs in healthy tissues of E. coioides, and CCR genes were highly expressed in the immune-relevant tissues. Analysis of gene expression after Singapore grouper iridovirus (SGIV) infection indicated that CCR genes are regulated in a gene-specific manner. CCR8a and CCR8b were significantly upregulated in the spleen and liver of resistant fish, indicating potential roles in immunity against the pathogen. Fluorescence microscopy revealed that CCR8a and CCR8b were expressed predominantly in the cytoplasm. Overexpression of CCR8a and CCR8b in grouper cells significantly inhibited the replication of SGIV, demonstrating that they delayed the occurrence of cytopathic effects induced by SGIV infection and inhibited viral gene transcription. CCR8a and CCR8b overexpression also significantly increased the expression of interferon (IFN)-related cytokines and activated IFN response element and IFN promoter activities. These results demonstrated that CCR8a and CCR8b might have an antiviral function against SGIV infect.

Mechanical and physio-biological properties of peptide-coated stent for re-endothelialization

Background

The aim of this study was to characterize the mechanical and physio-biological properties of peptide-coated stent (PCS) compared to commercialized drug-eluting stents (DESs).

Methods

WKYMVm (Trp-Lys-Tyr-Met-Val-D-Met), a stimulating peptide for homing endothelial colony-forming cell was specially synthesized and coated to bare metal stent (BMS) by dopamine-derived coordinated bond. Biological effects of PCS were investigated by endothelial cell proliferation assay and pre-clinical animal study. And mechanical properties were examined by various experiment.

Results

The peptide was well-coated to BMS and was maintained and delivered to 21 and 7 days in vitro and in vivo, respectively. Moreover, the proliferation of endothelial cell in PCS group was increased (approximately 36.4 ± 5.77%) in PCS group at 7 day of culture compare to BMS. Although, the radial force of PCS was moderated among study group. The flexibility of PCS was (0.49 ± 0.082 N) was greatest among study group. PCS did not show the outstanding performance in recoil and foreshortening test (3.1 ± 0.22% and 2.1 ± 0.06%, respectively), which was the reasonable result under the guide line of FDA (less than 7.0%). The nominal pressure (3.0 mm in a diameter) of PCS established by compliance analysis was 9 atm. The changing of PCS diameter by expansion was similar to other DESs, which is less than 10 atm of pressure for the nominal pressure.

Conclusions

These results suggest that the PCS is not inferior to commercialized DES. In addition, since the PCS was fabricated as polymer–free process, secondary coating with polymer-based immunosuppressive drugs such as –limus derivatives may possible.

Efficacy of dextran and peptide-everolimus bi-directional stent

Everolimus inhibits stent restenosis and the WKYMV (fluorescein isothiocyanate) peptide promotes endothelial homing. Dextran is a natural polymer that is widely used as a pharmaceutical agent. The purpose of this study was to develop a double-drug-coated stent using a bidirectional coating system and to examine the surface shape with in vitro experiments. Stent length was 16 mm and strut thickness was 70 µm (Chonnam National University Hospital Tiger stent). Optical and scanning electron microscopy showed good coating without cracks or bubbles. Fluorescein isothiocyanate-peptide was dip-coated on the lumen and the abluminal surface was coated with everolimus and dextran. Stents were coated with dextran, everolimus, or everolimus-dextran. The radial force and flexibility were measured to determine the mechanical properties. Contact angle testing was performed in all groups. Dextran and peptide as hydrophilic substances and everolimus as a hydrophobic substance were each coated on cover glasses (cobalt-chromium). A10 and human umbilical vein endothelial cells were used in the experiments. Water and dimethyl sulfoxide served as a control, and three drug groups were tested: peptide-everolimus, everolimus-dextran, and peptide-everolimus-dextran. Immunocytochemistry was performed to assess cell adhesion. Light intensity was plotted according to the average on nuclear staining. Experiments were conducted using 5-bromo-2'-deoxyuridine to investigate A10 and human umbilical vein endothelial cell proliferation. Cell adhesion and proliferation of peptide-everolimus-dextran were inhibited at A10, and human umbilical vein endothelial cell was found to proliferate with cell adhesion. On conclusion, dextran and peptide-everolimus bidirectional stent is effective in re-endothelialization and inhibition of cell proliferation.

A guide to chemokines and their receptors

The chemokines (or chemotactic cytokines) are a large family of small, secreted proteins that signal through cell surface G protein-coupled heptahelical chemokine receptors. They are best known for their ability to stimulate the migration of cells, most notably white blood cells (leukocytes). Consequently, chemokines play a central role in the development and homeostasis of the immune system, and are involved in all protective or destructive immune and inflammatory responses. Classically viewed as inducers of directed chemotactic migration, it is now clear that chemokines can stimulate a variety of other types of directed and undirected migratory behavior, such as haptotaxis, chemokinesis, and haptokinesis, in addition to inducing cell arrest or adhesion. However, chemokine receptors on leukocytes can do more than just direct migration, and these molecules can also be expressed on, and regulate the biology of, many nonleukocytic cell types. Chemokines are profoundly affected by post-translational modification, by interaction with the extracellular matrix (ECM), and by binding to heptahelical 'atypical' chemokine receptors that regulate chemokine localization and abundance. This guide gives a broad overview of the chemokine and chemokine receptor families; summarizes the complex physical interactions that occur in the chemokine network; and, using specific examples, discusses general principles of chemokine function, focusing particularly on their ability to direct leukocyte migration.

Cathepsin G and Its Role in Inflammation and Autoimmune Diseases

Cathepsin G belongs to the neutrophil serine proteases family, known for its function in killing pathogens. Studies over the past several years indicate that cathepsin G has important effects on inflammation and immune reaction, and may be a key factor in the pathogenesis of some autoimmune diseases. In this article, we discuss the roles of cathepsin G in inflammation, immune reaction, and autoimmune diseases. To our knowledge, this is the first study providing important information about cathepsin G in the pathogenesis of autoimmune diseases and suggesting that cathepsin G may be a new biomarker or treatment target.

The Formyl Peptide Receptors: Diversity of Ligands and Mechanism for Recognition

The formyl peptide receptors (FPRs) are G protein-coupled receptors that transduce chemotactic signals in phagocytes and mediate host-defense as well as inflammatory responses including cell adhesion, directed migration, granule release and superoxide production. In recent years, the cellular distribution and biological functions of FPRs have expanded to include additional roles in homeostasis of organ functions and modulation of inflammation. In a prototype, FPRs recognize peptides containing N-formylated methionine such as those produced in bacteria and mitochondria, thereby serving as pattern recognition receptors. The repertoire of FPR ligands, however, has expanded rapidly to include not only N-formyl peptides from microbes but also non-formyl peptides of microbial and host origins, synthetic small molecules and an eicosanoid. How these chemically diverse ligands are recognized by the three human FPRs (FPR1, FPR2 and FPR3) and their murine equivalents is largely unclear. In the absence of crystal structures for the FPRs, site-directed mutagenesis, computer-aided ligand docking and structural simulation have led to the identification of amino acids within FPR1 and FPR2 that interact with several formyl peptides. This review article summarizes the progress made in the understanding of FPR ligand diversity as well as ligand recognition mechanisms used by these receptors.

Characterization and expression analysis of two novel CCR6 chemokine receptors and their three potential ligands CCL20Ls of grouper (Epinephelus coioides) post Cryptocaryon irritans infection

CCR6 have been demonstrated playing an important role in immune cells homing to mucosal tissues, mediating antigen presentation and immune response in mammals. CCR6 in lower vertebrate leukocyte homing has not yet been revealed. Cryptocaryon irritans is believed to be a good pathogen model for skin and gill mucosal immunity. In this study, we identified two CCR6s and their three possible ligands CCL20 like cDNA sequences, designated as grouper EcCCR6A, EcCCR6B, EcCCL20L1, EcCCL20L2 and EcCCL20L3. It is interesting to find that EcCCR6A has a longer second extracellular loop than EcCCR6B, which is more similar to mammalian CCR6. Tissue distribution analysis showed that EcCCR6A pronouncedly dominates in gill and brain while EcCCR6B dominates in head kidney, trunk kidney and thymus. Three chemokine ligands have their own distinct expression pattern in health grouper tissues. EcCCL20L1 dominates in spleen and head kidney, EcCCL20L2 dominates in gill and thymus, whereas EcCCL20L3 dominates in skin and brain. The expression patterns of these chemokines and chemokine receptors were detected in C. irritans infected grouper and the results showed that EcCCR6A, EcCCR6B and EcCCL20L1 were significantly up-regulated in the skin of C. irritans infected fish, which indicated these two chemokine receptors and their ligand may play important role in immune cells' homing to skin mucosal immune tissues under pathogen caused inflammation.

Effect of a novel peptide, WKYMVm- and sirolimus-coated stent on re-endothelialization and anti-restenosis

The drug-eluting stent still has limitations such as thrombosis and inflammation. These limitations often occur in the absence of endothelialization. This study investigated the effects of WKYMVm- and sirolimus-coated stents on re-endothelialization and anti-restenosis. The WKYMVm peptide, specially synthesized for homing endothelial colony-forming cells, was coated onto a bare-metal stent with hyaluronic acid through a simple dip-coating method (designated HA-Pep). Thereafter, sirolimus was consecutively coated to onto the HA-Pep (designated Pep/SRL). The cellular response to stents by human umbilical-vein endothelial cells and vascular smooth-muscle cells was examined by XTT assay. Stents were implanted into rabbit iliac arteries, isolated 6 weeks post-implantation, and then subjected to histological analysis. The peptide was well attached to the surface of the stents and the sirolimus coating made the surface smooth. The release pattern for sirolimus was similar to that of commercial sirolimus-coated stents (57.2% within 7 days, with further release for up to 28 days). Endothelial-cell proliferation was enhanced in the HA-Pep group after 7 days of culture (38.2 ± 7.62%, compared with controls). On the other hand, the proliferation of smooth-muscle cells was inhibited in the Pep/SRL group after 7 days of culture (40.7 ± 6.71%, compared with controls). In an animal study, the restenosis rates for the Pep/SRL group (13.5 ± 4.50%) and commercial drug-eluting stents (Xience Prime™; 9.2 ± 7.20%) were lower than those for bare-metal stents (25.2 ± 4.52%) and HA-Pep stents (26.9 ± 3.88%). CD31 staining was incomplete for the bare-metal and Xience Prime™ groups. On the other hand, CD31 staining showed a consecutive linear pattern in the HA-Pep and Pep/SRL groups, suggesting that WKYMVm promotes endothelialization. These results indicate that the WKYMVm coating could promote endothelial healing, and consecutive coatings of WKYMVm and sirolimus onto bare-metal stents have a potential role in re-endothelialization and neointimal suppression.

Resolution of inflammation: targeting GPCRs that interact with lipids and peptides

There is a growing appreciation of the important role of resolution mediators in the successful termination of the inflammatory response. Here, we discuss the potential importance of the lipid and peptide proresolving mediators, in particular the resolvins and chemerin-derived peptides, which mediate their effects through specific G protein-coupled receptors (GPCRs).

Distinct signaling cascades elicited by different formyl peptide receptor 2 (FPR2) agonists

The formyl peptide receptor 2 (FPR2) is a remarkably versatile transmembrane protein belonging to the G-protein coupled receptor (GPCR) family. FPR2 is activated by an array of ligands, which include structurally unrelated lipids and peptide/proteins agonists, resulting in different intracellular responses in a ligand-specific fashion. In addition to the anti-inflammatory lipid, lipoxin A4, several other endogenous agonists also bind FPR2, including serum amyloid A, glucocorticoid-induced annexin 1, urokinase and its receptor, suggesting that the activation of FPR2 may result in potent pro- or anti-inflammatory responses. Other endogenous ligands, also present in biological samples, include resolvins, amyloidogenic proteins, such as beta amyloid (Aβ)-42 and prion protein (Prp)_106–126, the neuroprotective peptide, humanin, antibacterial peptides, annexin 1-derived peptides, chemokine variants, the neuropeptides, vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase activating polypeptide (PACAP)-27, and mitochondrial peptides. Upon activation, intracellular domains of FPR2 mediate signaling to G-proteins, which trigger several agonist-dependent signal transduction pathways, including activation of phospholipase C (PLC), protein kinase C (PKC) isoforms, the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway, the mitogen-activated protein kinase (MAPK) pathway, p38MAPK, as well as the phosphorylation of cytosolic tyrosine kinases, tyrosine kinase receptor transactivation, phosphorylation and nuclear translocation of regulatory transcriptional factors, release of calcium and production of oxidants. FPR2 is an attractive therapeutic target, because of its involvement in a range of normal physiological processes and pathological diseases. Here, we review and discuss the most significant findings on the intracellular pathways and on the cross-communication between FPR2 and tyrosine kinase receptors triggered by different FPR2 agonists.

Molecular characterization of three novel chemokine receptors in rainbow trout (Oncorhynchus mykiss)

Chemokines signal through a family of seven-transmembrane domain G-coupled receptors in order to regulate both leukocyte mobilization and activate the recruited cells. Although many chemokines have been identified in rainbow trout (Oncorhynchus mykiss), only a few chemokine receptors have been reported to date. In this work, we have cloned three novel chemokine receptors in rainbow trout. One of these receptors seems to be a clear orthologue of CCR6, while the second one constitutes a novel CCR9 gene different from the previous CCR9 reported in this species. This gene, which we have designated as CCR9B, represents another lineage of fish CCR9 genes, not previously identified. Finally, a deeper phylogenetic analysis of the third novel chemokine receptor gene, which had been identified on the basis of sequence similarity to CCR3, constitutes a novel lineage of CCR receptors which has no equivalent in humans and that may be teleost-specific. We have designated this novel gene as CCR13, to avoid any possible ascription to mammalian genes. Further transcriptional studies revealed that CCR6 was constitutively transcribed in thymus, gills, hindgut and peripheral blood leukocytes (PBLs), while CCR9B was strongly transcribed in thymus and PBLs but also in spleen, gills, hindgut and brain at lower levels. CCR13, on the other hand, was strongly detected in spleen, head kidney and PBLs and faintly in thymus, gills, brain and gonad. The data provided constitutes a step forward the identification of novel chemokine receptors that may contribute to a future understanding of chemokine signalling in fish.

CC chemokine receptors and chronic inflammation--therapeutic opportunities and pharmacological challenges

Chemokines are a family of low molecular weight proteins with an essential role in leukocyte trafficking during both homeostasis and inflammation. The CC class of chemokines consists of at least 28 members (CCL1-28) that signal through 10 known chemokine receptors (CCR1-10). CC chemokine receptors are expressed predominantly by T cells and monocyte-macrophages, cell types associated predominantly with chronic inflammation occurring over weeks or years. Chronic inflammatory diseases including rheumatoid arthritis, atherosclerosis, and metabolic syndrome are characterized by continued leukocyte infiltration into the inflammatory site, driven in large part by excessive chemokine production. Over years or decades, persistent inflammation may lead to loss of tissue architecture and function, causing severe disability or, in the case of atherosclerosis, fatal outcomes such as myocardial infarction or stroke. Despite the existence of several clinical strategies for targeting chronic inflammation, these diseases remain significant causes of morbidity and mortality globally, with a concomitant economic impact. Thus, the development of novel therapeutic agents for the treatment of chronic inflammatory disease continues to be a priority. In this review we introduce CC chemokine receptors as critical mediators of chronic inflammatory responses and explore their potential role as pharmacological targets. We discuss functions of individual CC chemokine receptors based on in vitro pharmacological data as well as transgenic animal studies. Focusing on three key forms of chronic inflammation--rheumatoid arthritis, atherosclerosis, and metabolic syndrome--we describe the pathologic function of CC chemokine receptors and their possible relevance as therapeutic targets.

Inflammatory cell trafficking across the blood-brain barrier: chemokine regulation and in vitro models

The blood-brain barrier (BBB) is the brain-specific capillary barrier that is critical for preventing toxic substances from entering the central nervous system (CNS). In contrast to vessels of peripheral organs, the BBB limits the exchange of inflammatory cells and mediators under physiological and pathological conditions. Clarifying these limitations and the role of chemokines in regulating the BBB would provide new insights into neuroprotective strategies in neuroinflammatory diseases. Because there is a paucity of in vitro BBB models, however, some mechanistic aspects of transmigration across the BBB still remain largely unknown. In this review, we summarize current knowledge of BBB cellular components, the multistep process of inflammatory cells crossing the BBB, functions of CNS-derived chemokines, and in vitro BBB models for transmigration, with a particular focus on new and recent findings.

Biochemical analysis of matrix metalloproteinase activation of chemokines CCL15 and CCL23 and increased glycosaminoglycan binding of CCL16

Leukocyte migration and activation is orchestrated by chemokines, the cleavage of which modulates their activity and glycosaminoglycan binding and thus their roles in inflammation and immunity. Early research identified proteolysis as a means of both activating or inactivating CXC chemokines and inactivating CC chemokines. Recent evidence has shown activating cleavages of the monocyte chemoattractants CCL15 and CCL23 by incubation with synovial fluid, although the responsible proteases could not be identified. Herein we show that CCL15 is processed in human synovial fluid by matrix metalloproteinases (MMPs) and serine proteases. Furthermore, a family-wide investigation of MMP processing of all 14 monocyte-directed CC chemokines revealed that each is precisely cleaved by one or more MMPs. By MALDI-TOF-MS, 149 cleavage sites were sequenced including the first reported instance of CCL1, CCL16, and CCL17 proteolysis. Full-length CCL15-(1–92) and CCL23-(1–99) were cleaved within their unique 31 and 32-amino acid residue extended amino termini, respectively. Unlike other CCL chemokines that lose activity and become receptor antagonists upon MMP cleavage, the prominent MMP-processed products CCL15-(25–92, 28–92) and CCL23-(26–99) are stronger agonists in calcium flux and Transwell CC receptor transfectant and monocytic THP-1 migration assays. MMP processing of CCL16-(1–97) in its extended carboxyl terminus yields two products, CCL16-(8–77) and CCL16-(8–85), with both showing unexpected enhanced glycosaminoglycan binding. Hence, our study reveals for the first time that MMPs activate the long amino-terminal chemokines CCL15 and CCL23 to potent forms that have potential to increase monocyte recruitment during inflammation.

Proteolytic cleavage of chemerin protein is necessary for activation to the active form, Chem157S, which functions as a signaling molecule in glioblastoma

Chemerin is a chemoattractant involved in innate and adaptive immunity as well as an adipokine implicated in adipocyte differentiation. Chemerin circulates as an inactive precursor in blood whose bioactivity is closely regulated through proteolytic processing at its C terminus. We developed methodology for production of different recombinant chemerin isoforms (chem163S, chem157S, and chem155A) which allowed us to obtain large quantities of these proteins with purity of >95%. Chem158K was generated from chem163S by plasmin cleavage. Characterization by mass spectrometry and Edman degradation demonstrated that both the N and C termini were correct for each isoform. Ca(2+) mobilization assays showed that the EC(50) values for chem163S and chem158K were 54.2 ± 19.9 nm and 65.2 ± 13.2 nm, respectively, whereas chem157S had a ∼50-fold higher potency with an EC(50) of 1.2 ± 0.7 nm. Chem155A had no agonist activity and weak antagonist activity, causing a 50% reduction of chem157S activity at a molar ratio of 100:1. Similar results were obtained in a chemotaxis assay. Because chem158K is the dominant form in cerebrospinal fluid from patients with glioblastoma (GBM), we examined the significance of chemerin in GBM biology. In silico analysis showed chemerin mRNA was significantly increased in tissue from grade III and IV gliomas. Furthermore, U-87 MG cells, a human GBM line, express the chemerin receptors, chemokine-like receptor 1 and chemokine receptor-like 2, and chem157S triggered Ca(2+) flux. This study emphasized the necessity of appropriate C-terminal proteolytic processing to generate the likely physiologic form of active chemerin, chem157S, and suggested a possible role in malignant GBM.

Human eosinophils produce and release a novel chemokine, CCL23, in vitro

BACKGROUND

CCL23 (MPIF1/CK-BETA-8) is a novel CC chemokine that plays important roles in the inhibition of myeloid progenitor cell development, the selective recruitment of resting T lymphocytes and monocytes, and the potentiation of VEGF-induced proliferation and migration of human endothelial cells. Since eosinophils participate in the pathogenesis of airway remodeling, we examined CCL23 production and release by human eosinophils in vitro.

METHODS

Using Ficoll and antibody-coated immunomagnetic beads, eosinophils and other blood cells were purified from peripheral blood samples obtained from normal subjects and mildly allergic patients. Eosinophils were cultured in the presence of 10 ng/ml granulocyte-macrophage colony-stimulating factor (GM-CSF), 10 ng/ml IL-5, 100 ng/ml IFN-γ, 100 ng/ml IFN-α, or immobilized secretory IgA (sIgA). Total mRNA was extracted after 6 h of culture, and mRNA expression was measured using a microarray and RT-PCR. The CCL23 concentrations in the supernatants and cell lysates after 24 and 48 h of culture were measured by ELISA.

RESULTS

CCL23 mRNAs (both CK-β8-1 and CK-β8) were constitutively expressed in fresh eosinophils, and their expression levels were higher than in other types of blood cells. CCL23 mRNAs were significantly increased by stimulation with GM-CSF and IL-5 and slightly by IFN-α and immobilized sIgA. Fresh eosinophils contained trace amounts of CCL23 protein. CCL23 was significantly released into the supernatant when the eosinophils were stimulated with GM-CSF or IL-5 but not with IFN-γ or immobilized sIgA.

CONCLUSION

Our data suggest that eosinophils produce and release CCL23 and may be involved in some in vivo physiological and pathological conditions.

Increased expression of the chemokine CCL23 in eosinophilic chronic rhinosinusitis with nasal polyps

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous chronic disease characterized by local inflammation of the sinonasal tissues. The pathogenesis of CRS remains controversial, but it has been associated with the accumulation of various immune and inflammatory cells in sinus tissue.

OBJECTIVES

The objective of this study was to investigate the expression of the chemokine CCL23, which is known to bind to CCR1 and recruit monocytes, macrophages, and dendritic cells, in patients with CRS.

METHODS

We collected nasal tissue from patients with CRS and control subjects. We assayed mRNA for CCL23 by using real-time PCR and measured CCL23 protein by means of ELISA, immunohistochemistry, and immunofluorescence.

RESULTS

CCL23 mRNA levels were significantly increased in nasal polyps (NPs) from patients with CRS with nasal polyps (CRSwNP; P < .05) compared with inferior turbinate and uncinate tissue from patients with CRS or control subjects. CCL23 protein levels were also increased in NPs, although these levels were not statistically significant. Immunohistochemical analysis revealed CCL23 expression in mucosal epithelial cells and inflammatory cells, but accumulation of CCL23(+) inflammatory cells occurred only in NPs. Immunofluorescence data showed CCL23 colocalization with eosinophil cationic protein-positive eosinophils. The concentration of CCL23 in NPs positively correlated with the concentration of eosinophil cationic protein, suggesting that eosinophils are major CCL23-producing cells in NPs. Finally, we found that CCL23 protein levels were significantly increased in NPs from patients with CRSwNP with aspirin sensitivity.

CONCLUSION

Overproduction of CCL23 in NPs might contribute to the pathogenesis of eosinophilic CRSwNP through the recruitment of CCR1(+) inflammatory cells, including monocytes and macrophages, and the amplification of local inflammation.

International Union of Basic and Clinical Pharmacology. LXXIII. Nomenclature for the formyl peptide receptor (FPR) family

Formyl peptide receptors (FPRs) are a small group of seven-transmembrane domain, G protein-coupled receptors that are expressed mainly by mammalian phagocytic leukocytes and are known to be important in host defense and inflammation. The three human FPRs (FPR1, FPR2/ALX, and FPR3) share significant sequence homology and are encoded by clustered genes. Collectively, these receptors bind an extraordinarily numerous and structurally diverse group of agonistic ligands, including N-formyl and nonformyl peptides of different composition, that chemoattract and activate phagocytes. N-formyl peptides, which are encoded in nature only by bacterial and mitochondrial genes and result from obligatory initiation of bacterial and mitochondrial protein synthesis with N-formylmethionine, is the only ligand class common to all three human receptors. Surprisingly, the endogenous anti-inflammatory peptide annexin 1 and its N-terminal fragments also bind human FPR1 and FPR2/ALX, and the anti-inflammatory eicosanoid lipoxin A4 is an agonist at FPR2/ALX. In comparison, fewer agonists have been identified for FPR3, the third member in this receptor family. Structural and functional studies of the FPRs have produced important information for understanding the general pharmacological principles governing all leukocyte chemoattractant receptors. This article aims to provide an overview of the discovery and pharmacological characterization of FPRs, to introduce an International Union of Basic and Clinical Pharmacology (IUPHAR)-recommended nomenclature, and to discuss unmet challenges, including the mechanisms used by these receptors to bind diverse ligands and mediate different biological functions.

Neutrophil serine proteases fine-tune the inflammatory response

Neutrophil serine proteases are granule-associated enzymes known mainly for their function in the intracellular killing of pathogens. Their extracellular release upon neutrophil activation is traditionally regarded as the primary reason for tissue damage at the sites of inflammation. However, studies over the past several years indicate that neutrophil serine proteases may also be key regulators of the inflammatory response. Neutrophil serine proteases specifically process and release chemokines, cytokines, and growth factors, thus modulating their biological activity. In addition, neutrophil serine proteases activate and shed specific cell surface receptors, which can ultimately prolong or terminate cytokine-induced responses. Moreover, it has been proposed that these proteases can impact cell viability through their caspase-like activity and initiate the adaptive immune response by directly activating lymphocytes. In summary, these studies point to neutrophil serine proteases as versatile mediators that fine-tune the local immune response and identify them as potential targets for therapeutic interventions.