Functional expression of chemokine receptor 2 by normal human eosinophils

The Effect of Anti-Chemokine Oral Drug XC8 on Cough Triggered by The Agonists of TRPA1 But Not TRPV1 Channels in Guinea Pigs

Introduction

Chronic cough heavily affects patients’ quality of life, and there are no effective licensed therapies available. Cough is a complication of severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) infection, asthma, and other diseases. Patients with various diseases have a different profile of tussive responses to diverse cough triggers, thereby suggesting sundry mechanisms of neuronal dysfunctions. Previously, we demonstrated that the small molecule drug XC8 shows a clinical anti-asthmatic effect. The objective of the present study was to investigate the effect of XC8 on cough.

Methods

We studied the antitussive effect of XC8 on cough induced by agonists activating human transient receptor potential (TRP) cation channels TRPA1 or TRPV1 in guinea pigs. We checked the agonistic/antagonistic activity of XC8 on the human cation channels TRPA1, TRPV1, TRPM8, P2X purinoceptor 2 (P2X2), and human acid sensing ion channel 3 (hASIC3) in Fluorescent Imaging Plate Reader (FLIPR) assay.

Results

XC8 demonstrated clear antitussive activity and dose-dependently inhibited cough in guinea pigs induced by citric acid alone (up to 67.1%) or in combination with IFN-γ (up to 76.4%). XC8 suppressed cough reflexes induced by the repeated inhalation of citric acid (up to 80%) or by cinnamaldehyde (up to 60%). No activity of XC8 against cough evoked by capsaicin was revealed. No direct agonistic/antagonistic activity of XC8 on human TRPA1, TRPV1, TRPM8, P2X2, or hASIC3 was detected.

Conclusions

XC8 acts against cough evoked by the activation of TRPA1 (citric acid/cinnamaldehyde) but not TRPV1 (capsaicin) channels. XC8 inhibits the cough reflex and suppresses the cough potentiation by IFN-γ. XC8 might be of significant therapeutic value for patients suffering from chronic cough associated with inflammation.

New Anti-Chemokine Oral Drug XC8 in the Treatment of Asthma Patients with Poor Response to Corticosteroids: Results of a Phase 2A Randomized Controlled Clinical Trial

Introduction

A significant number of patients with moderate asthma remain symptomatic despite treatment with inhaled corticosteroids (ICS). These patients do not yet meet the criteria for oral corticosteroids (OCS) and monoclonal antibodies. The new anti-chemokine oral drug XC8 could represent an alternative treatment option for these patients. The objective of this trial was to evaluate the effect of different doses of the XC8 in patients with partly controlled asthma in a phase 2a clinical trial.

Methods

A double-blind, parallel-group, randomized, multicenter, phase 2a trial was conducted at 12 sites in Russia. Patients with asthma were randomized into four groups (n = 30 each) to receive XC8 at 2 mg, 10 mg, 100 mg or placebo once-daily for 12 weeks in addition to low-dose ICS with or without LABA. Efficacy and safety parameters were evaluated at weeks 0, 2, 6, and 12.

Results

No statistically significant difference between the treatment arms in the number of patients with adverse events was observed. The primary endpoint, improvement of forced expiratory volume in 1 s (FEV₁) % predicted over 12 weeks compared to placebo, was not statistically significant. The treatment of patients with XC8 (100 mg) resulted in statistically and clinically significant improvements in FEV₁ compared to baseline (7.40% predicted, p < 0.001). Patients with elevated peripheral blood eosinophil count (PBEC, > 300 cells/μl) or serum interferon-γ (IFN-γ) level (> 100 pg/mL) treated with XC8 (100 mg) achieved a statistically significant improvement in FEV₁ (11.33% predicted or 8.69% predicted, respectively, p < 0.05) as compared to the baseline versus the placebo. The strongest effect was observed in patients with both high PBEC and IFN-γ level. Pharmacodynamic engagement was demonstrated through the reduction of serum levels of C–C motif ligand 2 (CCL2) and C–X–C motif chemokine 10 (CXCL10). Treatment with XC8 (100 mg) alleviated resistance to maintenance ICS therapy in patients with elevated IFN-γ level.

Conclusions

Given the high safety, oral route of administration, and efficacy, XC8 may provide a promising treatment option for patients with mild-to-moderate asthma.

Trial Registration

795–30/12/2015 (Ministry of Health Russian Federation), NCT03450434 (ClinicalTrials.gov).

Electronic supplementary material

The online version of this article (10.1007/s41030-020-00134-5) contains supplementary material, which is available to authorized users.

An update on immune dysregulation in obesity-related insulin resistance

Obesity is associated with chronic low-grade inflammation of the adipose tissue (AT) that might develop into systemic inflammation, insulin resistance (IR) and an increased risk of type 2 diabetes mellitus (T2DM) in severe obese rodents and humans. In the lean state, small normal adipocytes and AT macrophages interact with each other to maintain metabolic homeostasis but during obesity, enlarged adipocytes secrete inflammatory mediators and express immune receptors to recruit immune cells and aggravate the inflammation. The better understanding of the obesity-related inflammatory milieu and the sequential events leading to IR could be helpful in designing new preventive and therapeutic strategies. The present review will discuss the cellular and molecular abnormalities participating in the pathogenesis of obesity in obese individuals as well as high-fat diet (HFD)-fed mice, a mouse model of obesity.

Regulation of Eosinophil and Group 2 Innate Lymphoid Cell Trafficking in Asthma

Asthma is an inflammatory disease usually characterized by increased Type 2 cytokines and by an infiltration of eosinophils to the airways. While the production of Type 2 cytokines has been associated with T_H2 lymphocytes, increasing evidence indicates that group 2 innate lymphoid cells (ILC2) play an important role in the production of the Type 2 cytokines interleukin (IL)-5 and IL-13, which likely amplifies the recruitment of eosinophils from the blood to the airways. In that regard, recent asthma treatments have been focusing on blocking Type 2 cytokines, notably IL-4, IL-5, and IL-13. These treatments mainly result in decreased blood or sputum eosinophil counts as well as decreased asthma symptoms. This supports that therapies blocking eosinophil recruitment and activation are valuable tools in the management of asthma and its severity. Herein, we review the mechanisms involved in eosinophil and ILC2 recruitment to the airways, with an emphasis on eotaxins, other chemokines as well as their receptors. We also discuss the involvement of other chemoattractants, notably the bioactive lipids 5-oxo-eicosatetraenoic acid, prostaglandin D₂, and 2-arachidonoyl-glycerol. Given that eosinophil biology differs between human and mice, we also highlight and discuss their responsiveness toward the different eosinophil chemoattractants.

CCL26/eotaxin-3 is more effective to induce the migration of eosinophils of asthmatics than CCL11/eotaxin-1 and CCL24/eotaxin-2

CCL11, CCL24, and CCL26 are chemokines involved in the recruitment of eosinophils into tissues and mainly activate CCR3. Whereas the genomic or pharmacological inhibition of CCR3 prevents the development of experimental asthma in rodents, it only impairs the recruitment of eosinophils by ∼40% in humans. As humans, but not rodents, express CCL26, we investigated the impact of CCL11, CCL24, and CCL26 on human eosinophils recruitment and evaluated the involvement of CCR3. The migration of eosinophils of healthy volunteers was similar for the three eotaxins. Eosinophils of mild asthmatics had a greater response to CCL11 and a much greater response to CCL26. Whereas all eotaxins induced the migration of eosinophil of asthmatics from 0 to 6 h, CCL26 triggered a second phase of migration between 12 and 18 h. Given that the CCR3 antagonists SB 328437 and SB 297006 inhibited the 5-oxo-eicosatetraenoate-induced migration of eosinophils and that the CCR3 antagonist UCB 35625 was not specific for CCR3, CCR3 blockade was performed with the CCR3 mAb. This antibody completely blocked the effect of all eotaxins on eosinophils of healthy subjects and the effect of CCL24 on the eosinophils of asthmatics. Interestingly, CCR3 blockade did not affect the second migration phase induced by CCL26 on eosinophils of asthmatics. In conclusion, CCL26 is a more effective chemoattractant than CCL11 and CCL24 for eosinophils of asthmatics. The mechanism of this greater efficiency is not yet defined. However, these results suggest that CCL26 may play a unique and important role in the recruitment of eosinophils in persistent asthma.

Macrophage/epithelial cell CCL2 contributes to rhinovirus-induced hyperresponsiveness and inflammation in a mouse model of allergic airways disease

Human rhinovirus (HRV) infections lead to exacerbations of lower airways disease in asthmatic patients but not in healthy individuals. However, underlying mechanisms remain to be completely elucidated. We hypothesized that the Th2-driven allergic environment enhances HRV-induced CC chemokine production, leading to asthma exacerbations. Ovalbumin (OVA)-sensitized and -challenged mice inoculated with HRV showed significant increases in the expression of lung CC chemokine ligand (CCL)-2/monocyte chemotactic protein (MCP)-1, CCL4/macrophage inflammatory protein (MIP)-1β, CCL7/MCP-3, CCL19/MIP-3β, and CCL20/MIP3α compared with mice treated with OVA alone. Inhibition of CCL2 with neutralizing antibody significantly attenuated HRV-induced airways inflammation and hyperresponsiveness in OVA-treated mice. Immunohistochemical stains showed colocalization of CCL2 with HRV in epithelial cells and CD68-positive macrophages, and flow cytometry showed increased CCL2(+), CD11b(+) cells in the lungs of OVA-treated, HRV-infected mice. Compared with lung macrophages from naïve mice, macrophages from OVA-exposed mice expressed significantly more CCL2 in response to HRV infection ex vivo. Pretreatment of mouse lung macrophages and BEAS-2B human bronchial epithelial cells with interleukin (IL)-4 and IL-13 increased HRV-induced CCL2 expression, and mouse lung macrophages from IL-4 receptor knockout mice showed reduced CCL2 expression in response to HRV, suggesting that exposure to these Th2 cytokines plays a role in the altered HRV response. Finally, bronchoalveolar macrophages from children with asthma elaborated more CCL2 upon ex vivo exposure to HRV than cells from nonasthmatic patients. We conclude that CCL2 production by epithelial cells and macrophages contributes to HRV-induced airway hyperresponsiveness and inflammation in a mouse model of allergic airways disease and may play a role in HRV-induced asthma exacerbations.

Autoantibodies in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multifactorial disorder with multigenic inheritance and various environmental factors implicated in its aetiopathogenesis. Despite the multiple mechanisms involved in the aetiology of SLE being elusive, recent studies have made progress in our understanding of the pathogenic mechanisms via abnormal regulation of cell-mediated and humoral immunity that lead to tissue damage. The heterogeneity of the clinical manifestations probably reflects the complexity of the disease pathogenesis itself. The immune system in SLE is characterised by a complex interplay between overactive B cells, abnormally activated T cells and antigen-presenting cells. This interplay leads to the production of an array of inflammatory cytokines, apoptotic cells, diverse autoantibodies and immune complexes that in turn activate effector cells and the complement system, leading to tissue injury and damage which are the hallmarks of the clinical manifestations. SLE patients have dysregulation of inflammatory cytokines, chemokines and immune response-related genes, as well as of the genes involved in apoptosis, signal transduction and the cell cycle.

Eosinophils in innate immunity: an evolving story

Eosinophils are innate immune leukocytes found in relatively low numbers within the blood. Terminal effector functions of eosinophils, deriving from their capacity to release their content of tissue-destructive cationic proteins, have historically been considered primary effector mechanisms against specific parasites, and are likewise implicated in tissue damage accompanying allergic responses such as asthma. However, the past decade has seen dramatic advancements in the field of eosinophil immunobiology, revealing eosinophils to also be key participants in many other facets of innate immunity, from bridging innate and adaptive immune responses to orchestrating tissue remodeling events. Here, we review the multifaceted functions of eosinophils in innate immunity that are currently known, and discuss new avenues in this evolving story.

Urban particulate matter in Beijing, China, enhances allergen-induced murine lung eosinophilia

It has been reported that ambient particulate matter (PM) in some large cities, such as Beijing, China, causes adverse respiratory health effects. However, there is currently no experimental report on the relationship between bronchial asthma and urban PM (UPM) in northeast Asia. In this study, the microbial and chemical substances adsorbed onto UPM collected in Beijing were excluded by heat-treatment at 360 degrees C for 30 min. The effects of UPM or heated UPM (H-UPM) toward allergic lung inflammation were compared in murine lungs to investigate the role of organic substances. ICR mice were administrated intratracheally with the two kinds of UPM and/or ovalbumin (OVA) 4 times at 2-week intervals. UPM and H-UPM enhanced eosinophil recruitment induced by OVA in the alveoli and in the submucosa of the airway, which has a goblet cell proliferation in the bronchial epithelium. UPM and H-UPM synergistically increased Th-2 cytokines--interleukin (IL)-4 and IL-13, eosinophil-relevant cytokines and chemokines, such as IL-5 and monocyte chemotactic protein-3 (MCP-3), induced by OVA in bronchoalveolar lavage fluid (BALF). The enhancing effects were much greater in UPM than in H-UPM. UPM induced adjuvant effects on specific immunoglobulin E (IgE) and IgG1 production by OVA. In an in vitro study using RAW264.7 cells, UPM increased the expression of Toll-like receptor 2 (TLR2) mRNA, but not TLR4 mRNA. H-UPM caused no expression of both TLR mRNAs. These results suggest that the aggravated lung eosinophilia in UPM was due to activation of a Th2-associated immune response via the activation of TLR2 by microbial materials. Chemical materials of air pollutant origin contained in UPM, and inorganic components (elemental carbon, mineral elements) in H-UPM, could also cause the aggravation.

MKP1 regulates the induction of MCP1 by Streptococcus pneumoniae pneumolysin in human epithelial cells

Epithelial cells act as the first line of host defense against microbes by producing a range of different molecules for clearance. Chemokines facilitate the clearance of invaders through the recruitment of leukocytes. Thus, upregulation of chemokine expression represents an important innate host defense response against invading microbes such as Streptococcus pneumoniae. In this study, we report that the expression of Monocyte Chemotactic Protein 1 (MCP1) was highly induced in response to S. pneumoniae in vitro and in vivo. Among numerous virulence factors, pneumococcal pneumolysin was found to be the major factor responsible for this induction. Furthermore, MCP1 induction was mediated by the p38 mitogen-activated protein kinase (MAPK) whose activation was controlled by MAPK phosphatase 1 (MKP1). Therefore, this study reveals novel roles of pneumolysin in mediating MKP1 expression for the regulation of MCP1 expression in human epithelial cells.

Intracellular signaling mechanisms regulating the activation of human eosinophils by the novel Th2 cytokine IL-33: implications for allergic inflammation

The novel interleukin (IL)-1 family cytokine IL-33 has been shown to activate T helper 2 (Th2) lymphocytes, mast cells and basophils to produce an array of proinflammatory cytokines, as well as to mediate blood eosinophilia, IgE secretion and hypertrophy of airway epithelium in mice. In the present study, we characterized the activation of human eosinophils by IL-33, and investigated the underlying intracellular signaling mechanisms. IL-33 markedly enhanced eosinophil survival and upregulated cell surface expression of the adhesion molecule intercellular adhesion molecule (ICAM)-1 on eosinophils, but it suppressed that of ICAM-3 and L-selectin. In addition, IL-33 mediates significant release of the proinflammatory cytokine IL-6 and the chemokines CXCL8 and CCL2. We found that IL-33-mediated enhancement of survival, induction of adhesion molecules, and release of cytokines and chemokines were differentially regulated by activation of the nuclear factor (NF)-kappaB, p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) pathways. Furthermore, we compared the above IL-33 activities with two structurally and functionally related cytokines, IL-1beta and IL-18. IL-1beta, but not IL-18, markedly upregulated cell surface expression of ICAM-1. IL-1beta and IL-18 also significantly enhanced eosinophil survival, and induced the release of IL-6 and chemokines CXCL8 and CCL2 via the activation of the NF-kappaB, p38 MAPK and ERK pathways. Synergistic effects on the release of IL-6 were also observed in combined treatment with IL-1beta, IL-18 and IL-33. Taken together, our findings provide insight into IL-33-mediated activation of eosinophils via differential intracellular signaling cascades in the immunopathogenesis of allergic inflammation.

Corneal and conjunctival fibroblasts are major sources of eosinophil-recruiting chemokines

BACKGROUND

Differential expression of chemokine genes were investigated in various types of ocular surface cells.

METHODS

Primary cultures of human corneal epithelial cells (n = 3), corneal fibroblasts (n = 2), conjunctival epithelial cells (n = 2) and conjunctival fibroblasts (n = 2) were established and incubated with or without interleukin (IL)-4 (30ng/ml) and tumor necrosis factor (TNF)-alpha(30ng/ml) for 24 hours. Gene transcription levels of 33 chemokines and production of 4 chemokines were analyzed.

RESULTS

After stimulation, chemokine expression increased for 18 of 33 coded chemokine gene transcripts. In stimulated conjunctival and corneal cells, CC chemokine genes increased in fibroblasts (expression of 6 out of 8 genes), while CXC chemokine genes increased in both epithelial cells (expression of 4 out of 9 genes in conjunctival epithelial cells and 7 out of 9 genes in corneal epithelial cells) and in fibroblasts (expression of 8 out of 9 genes in conjunctival and corneal fibroblasts). Except for MCP-1, gene transcription levels for most CC chemokines were inducible and, except for IP-10 and I-TAC, most CXC chemokines were constitutively expressed. Corneal epithelial cell and fibroblast production patterns for eotaxin-1, MCP-1 and IP-10 were comparable to the mRNA expression pattern.

CONCLUSIONS

Corneal and conjunctival fibroblasts exhibited marked increases in the expression of chemokines upon stimulation with TNF-alpha and IL-4, suggesting that fibroblasts may be one of the primary sources of chemokines in allergic conjunctival diseases. Therefore, regulation of chemokine production from these cells may be an effective strategy for treating such diseases.

House dust mite extracts activate cultured human dermal endothelial cells to express adhesion molecules and secrete cytokines

The human skin contacts molecules from house dust mites that are ubiquitous in many environments. These mite-derived molecules may penetrate the skin epidermis and dermis and contact microvascular endothelial cells and influence their function. The purpose of this study was to determine the response of normal human dermal microvascular endothelial cells to extracts of the dust mites, Dermatophagoides farinae, D. pteronyssinus, and Euroglyphus maynei with and without endotoxin (lipopolysaccharide). Endothelial cells were stimulated with mite extracts and the expression of surface molecules and the secretion of cytokines were measured in the absence and presence of polymyxin B to bind endotoxin. All three mite extracts stimulated endothelial cells to express intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin and to secrete interleukin (IL)-6, IL-8, monocyte chemoattractant protein (MCP-1), and granulocyte/macrophage colony stimulating factor (GM-CSF). Euroglyphus maynei-induced expression of all the cell surface molecules was not inhibited when the endotoxin activity in the mite extract was inhibited. In contrast, endothelial cells challenged with D. farinae or D. pteronyssinus extract depleted of endotoxin activity expressed only constitutive levels of ICAM-1, VCAM-1, and E-selectin. D. farinae and E. maynei extracts depleted of endotoxin activity still induced secretion of IL-8 and MCP-1 but at reduced levels. Only constitutive amounts of IL-6, G-CSF, and GM-CSF were secreted in response to any of the endotoxin-depleted mite extracts. Extracts of D. farinae, D. pteronyssinus, and E. maynei contain both endotoxins and other molecules that can stimulate expression of cell adhesion molecules and chemokine receptors and the secretion of cytokines by normal human microvascular endothelial cells.

The effects of microbial materials adhered to Asian sand dust on allergic lung inflammation

Asian sand dust (ASD) containing microbiological materials, sulfate (SO(4)(2)), and nitrate (NO(3)(-) ) derived from air pollutants in East China, reportedly cause adverse respiratory health effects. ASD aggravates ovalbumin (OVA)-associated experimental lung eosinophilia. In this study, the toxic materials adsorbed onto ASD were excluded by heat treatment at 360 degrees C for 30 min. The effects of nonheated ASD or heated ASD (H-ASD) toward the allergic lung inflammation were compared in murine lungs. ICR mice were administered intratracheally with normal saline (control), H-ASD, ASD, OVA, OVA + H-ASD, and OVA + ASD, four times at 2-week intervals. ASD only increased neutrophils in bronchoalveolar lavage fluids (BALFs) along with pro-inflammatory mediators, such as keratinocyte chemoattractant (KC). H-ASD and ASD enhanced eosinophil recruitment induced by OVA in the alveoli and in the submucosa of the airway, which has a goblet cell proliferation in the bronchial epithelium. The two ASDs synergistically increased interleukin-5 (IL-5), monocyte chemotactic protein-3 (MCP-3), and eotaxin, which were associated with OVA, in BALF. The enhancing effects were much greater in ASD than in H-ASD. The two ASDs induced the adjuvant effects to specific IgE and IgG1 production by OVA. In the in vitro study using RAW264.7 cells, ASD increased the expression of Toll-like receptor 2 (TLR 2) mRNA but not TLR4 mRNA. H-ASD caused no expression of either TLR mRNA. These results suggest that the aggravated lung eosinophilia by ASD may be due to activation of Th2-associated immune response via the activation of TLR2 by microbial components adhered to ASD.

Signalling mechanisms regulating the activation of human eosinophils by mast-cell-derived chymase: implications for mast cell-eosinophil interaction in allergic inflammation

Allergic diseases such as asthma and allergic dermatitis are associated with the degranulation of mast cells. Chymase, a mast-cell-specific protease, is the major component in mast cell granules that can induce eosinophil infiltration into inflammatory sites. We examined the immunopathological mechanisms for the activation of eosinophils by chymase in allergic inflammation. Cytokines were measured by cytometric bead array Flex Sets multiplex assay using flow cytometry and enzyme-linked immunosorbent assay. Adhesion molecules, migration and intracellular signalling pathways were assessed by flow cytometry, Boyden chamber assay and Western blot, respectively. Chymase suppressed the apoptosis of eosinophils and induce the release of the cytokine interleukin-6 (IL-6) and chemokines CXCL8, CCL2 and CXCL1 by eosinophils dose-dependently. It also up-regulated the surface expression of adhesion molecule CD18 and stimulated the chemokinetic migration of eosinophils. The expressions of adhesion molecules, cytokines and chemokines, and chemokinetic migration were differentially regulated by the activation of extracellular signal-regulated kinase, p38 mitogen-activated protein kinase, Akt, Janus-activated kinase and nuclear factor-kappaB pathways. Chymase therefore plays a pivotal immunological role in the interaction between mast cells and eosinophils in allergic diseases such as allergic dermatitis by inducing adhesion molecule-mediated chemokinetic migration and inflammatory cytokines and chemokines of eosinophils, through multiple intracellular signalling molecules and transcription factor. Our results therefore provide a further biochemical basis for the pathogenesis of allergic inflammation consequent on the interaction between mast cells and eosinophils, and give insight for the development of new therapies.

Leukotriene B4 is essential for selective eosinophil recruitment following allergen challenge of CD4+ cells in a model of chronic eosinophilic inflammation

Subcutaneous heat-coagulated egg white implants (EWI) induce chronic, intense local eosinophilia in mice, followed by asthma-like responses to airway ovalbumin challenge. Our goal was to define the mechanisms of selective eosinophil accumulation in the EWI model. EWI carriers were challenged i.p. with ovalbumin and the contributions of cellular immunity and inflammatory mediators to the resulting leukocyte accumulation were defined through cell transfer and pharmacological inhibition protocols. Eosinophil recruitment required Major Histocompatibility Complex Class II expression, and was abolished by the leukotriene B4 (LTB4) receptor antagonist CP 105.696, the 5-lipoxygenase inhibitor BWA4C and the 5-lipoxygenase activating protein inhibitor MK886. Eosinophil recruitment in EWI carriers followed transfer of: a) CD4+ (but not CD4-) cells, harvested from EWI donors and restimulated ex vivo; b) their cell-free supernatants, containing LTB4. Restimulation in the presence of MK886 was ineffective. CC chemokine receptor ligand (CCL)5 and CCL2 were induced by ovalbumin challenge in vivo. mRNA for CCL17 and CCL11 was induced in ovalbumin-restimulated CD4+ cells ex vivo. MK886 blocked induction of CCL17. Pretreatment of EWI carriers with MK886 eliminated the effectiveness of exogenously administered CCL11, CCL2 and CCL5. In conclusion, chemokine-producing, ovalbumin-restimulated CD4+ cells initiate eosinophil recruitment which is strictly dependent on LTB4 production.

Skin reactivity and local cell recruitment in human atopic and nonatopic subjects by CCL2/MCP-1 and CCL3/MIP-1alpha

BACKGROUND

Monocyte chemotactic protein (MCP-1/CCL2), the ligand for CCR2 and CCR5, and macrophage inflammatory protein-1alpha (MIP-1alpha/CCL3), the ligand for CCR1 and CCR5, are potent chemo-attractants in vitro and produce lesions in experimental animals, which resemble immediate and delayed-type hypersensitivity (DTH) reactions. CCL3 induces mononuclear cell and granulocyte infiltration in human atopic and nonatopic skin. Whether CCL2 (MCP-1) has comparable activity in man is uncertain as is the capacity of both the chemokines to elicit immediate- and DTH-like reactions in humans.

METHODS

Inflammatory cells were counted by immunohistochemistry in 24 and 48-h skin biopsies from atopics and nonatopics after intradermal injection of CCL2 and CCL3. Immediate (15 min) wheals-and-flares and delayed (24 and 48 h) indurations were also recorded.

RESULTS

Both chemokines induced immediate- (15 min) and delayed (24 and 48 h) reactions, which were associated with significant infiltrations of CD68+ macrophages, CD3+, CD4+ (but not CD8+) T cells, neutrophils, and eosinophils in biopsies from injection sites. CCL2, but not CCL3, also induced infiltration of basophils. Neither chemokine produced significant changes in the numbers of tryptase+ cutaneous mast cells. There were no differences in the pattern of skin reactivity or the numbers of infiltrating leukocytes in response to CCL2 and CCL3 between atopic and nonatopic subjects. In general, maximal infiltration of inflammatory cells was observed at the 24-h, rather than the 48-h, time point.

CONCLUSIONS

CCL2 and CCL3 induce both immediate and delayed skin reactions in atopics and nonatopics, and evoke a similar profile of local T cell/macrophage and granulocyte recruitment which, in general, confirm previous in vitro findings and in vivo experimental animal data.

Alterations in the function of circulating mononuclear cells derived from patients with Crohn's disease treated with mastic

AIM

To assess the effects of mastic administration on cytokine production of circulating mononuclear cells of patients with active Crohn's disease (CD).

METHODS

The study was conducted in patients with established mildly to moderately active CD, attending the outpatient clinics of the hospital, and in healthy controls. Recruited to a 4 wk treatment with mastic caps (6 caps/d, 0.37 g/cap) were 10 patients and 8 controls, all of who successfully completed the protocol. Interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), monocyte chemotactic protein-1 (MCP-1), macrophage migration inhibitory factor (MIF) and intracellular antioxidant glutathione (GSH) were evaluated in peripheral blood mononuclear cells (PBMC) before and after treatment.

RESULTS

Treating CD patients with mastic resulted in the reduction of TNF-alpha secretion (2.1 +/- 0.9 ng/mL vs 0.5 +/- 0.4 ng/mL, P = 0.028). MIF release was significantly increased (1.2 +/- 0.4 ng/mL vs 2.5 +/- 0.7 ng/mL, P = 0.026) meaning that random migration and chemotaxis of monocytes/macrophages was inhibited. No significant changes were observed in IL-6, MCP-1 and GSH concentrations.

CONCLUSION

This study shows that mastic acts as an immunomodulator on PBMC, acting as a TNF-alpha inhibitor and a MIF stimulator. Although further double-blind, placebo-controlled studies in a large number of patients is required to clarify the role of this natural product, this finding provides strong evidence that mastic might be an important regulator of immunity in CD.

Alterations in the function of circulating mononuclear cells derived from patients with Crohn's disease treated with mastic

AIM

To assess the effects of mastic administration on cytokine production of circulating mononuclear cells of patients with active Crohn's disease (CD).

METHODS

The study was conducted in patients with established mildly to moderately active CD, attending the outpatient clinics of the hospital, and in healthy controls. Recruited to a 4 wk treatment with mastic caps (6 caps/d, 0.37 g/cap) were 10 patients and 8 controls, all of who successfully completed the protocol. Interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), monocyte chemotactic protein-1 (MCP-1), macrophage migration inhibitory factor (MIF) and intracellular antioxidant glutathione (GSH) were evaluated in peripheral blood mononuclear cells (PBMC) before and after treatment.

RESULTS

Treating CD patients with mastic resulted in the reduction of TNF-alpha secretion (2.1 +/- 0.9 ng/mL vs 0.5 +/- 0.4 ng/mL, P = 0.028). MIF release was significantly increased (1.2 +/- 0.4 ng/mL vs 2.5 +/- 0.7 ng/mL, P = 0.026) meaning that random migration and chemotaxis of monocytes/macrophages was inhibited. No significant changes were observed in IL-6, MCP-1 and GSH concentrations.

CONCLUSION

This study shows that mastic acts as an immunomodulator on PBMC, acting as a TNF-alpha inhibitor and a MIF stimulator. Although further double-blind, placebo-controlled studies in a large number of patients is required to clarify the role of this natural product, this finding provides strong evidence that mastic might be an important regulator of immunity in CD.

Alterations in the function of circulating mononuclear cells derived from patients with Crohn’s disease treated with mastic

AIM: To assess the effects of mastic administration on cytokine production of circulating mononuclear cells of patients with active Crohn's disease (CD).

METHODS: The study was conducted in patients with established mildly to moderately active CD, attending the outpatient clinics of the hospital, and in healthy controls. Recruited to a 4 wk treatment with mastic caps (6 caps/d,0.37 g/cap) were 10 patients and 8 controls, all of who successfully completed the protocol. Interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), monocyte chemotactic protein-1 (MCP-1), macrophage migration inhibitory factor (MIF) and intracellular antioxidant glutathione (GSH) were evaluated in peripheral blood mononuclear cells (PBMC) before and after treatment.

RESULTS: Treating CD patients with mastic resulted in the reduction of TNF-α secretion (2.1 ± 0.9 ng/mL vs 0.5 ± 0.4 ng/mL, P = 0.028). MIF release was significantly increased (1.2 ± 0.4 ng/mL vs 2.5 ± 0.7 ng/mL, P = 0.026) meaning that random migration and chemotaxis of monocytes/macrophages was inhibited. No significant changes were observed in IL-6, MCP-1 and GSH concentrations.

CONCLUSION: This study shows that mastic acts as an immunomodulator on PBMC, acting as a TNF-α inhibitor and a MIF stimulator. Although further double-blind, placebo-controlled studies in a large number of patients is required to clarify the role of this natural product, this finding provides strong evidence that mastic might be an important regulator of immunity in CD.

Leptin-mediated cytokine release and migration of eosinophils: Implications for immunopathophysiology of allergic inflammation

Leptin is a pleiotropic adipocyte-derived cytokine used in hypothalamic regulation of body weight and modulation of immune response by stimulating T cells, macrophages and neutrophils. Leptin has been shown to be an eosinophil survival factor. We examined the immunopathological mechanisms for the activation of human eosinophils from healthy volunteers by leptin in allergic inflammation. Adhesion molecules, cytokines and cell migration were assessed by flow cytometry, ELISA and Boyden chamber assay, respectively. Intracellular signaling molecules were investigated by membrane array and Western blot. Leptin could up-regulate cell surface expression of adhesion molecule ICAM-1 and CD18 but suppress ICAM-3 and L-selectin on eosinophils. Leptin could also stimulate the chemokinesis of eosinophils, and induce the release of inflammatory cytokines IL-1beta and IL-6, and chemokines IL-8, growth-related oncogene-alpha and MCP-1. We found that leptin-mediated induction of adhesion molecules, release of cytokines and chemokines, and chemokinesis were differentially regulated by the activation of ERK, p38 MAPK and NF-kappaB. In view of the above results and elevated production of leptin in patients with allergic diseases such as atopic asthma and atopic dermatitis, leptin could play crucial immunopathophysiological roles in allergic inflammation by activation of eosinophils via differential intracellular signaling cascades.

Synergistic effect of PGD2 via prostanoid DP receptor on TNF-alpha-induced production of MCP-1 and IL-8 in human monocytic THP-1 cells

Prostaglandin (PG) D2, a major cyclooxygenase metabolite generated predominantly from immunologically stimulated mast cells, is thought to contribute to the pathogenesis of allergic diseases via the two PGD2 receptors, prostanoid DP receptor and chemoattractant receptor homologous molecule expressed on Th2 cells (CRTH2). Monocytes are known to express the prostanoid DP receptor, however, the role of it in inflammatory responses is still unclear. In the present study, to clarify the functional roles of prostanoid DP receptor on monocytes, we examined the effect of PGD2 on the production of monocyte chemoattractant protein (MCP)-1 and interleukin (IL)-8 from a human monocytic cell line, THP-1. Single activation of prostanoid DP receptor hardly produced any cytokines or chemokines. However, activation with PGD2 in the presence of tumor necrosis factor (TNF)-alpha mediated significant production of MCP-1 and IL-8, but not the other cytokines and chemokines, in comparison to single stimulation with TNF-alpha. In addition, the selective prostanoid DP receptor antagonist, pinagladin ((Z)-7-[(1R,2R,3S,5S)-2-(benzothiophen-3-ylcarbonylamide)-10-norpinan-3-yl]hept-5-enoic acid) inhibited the production of MCP-1 and IL-8 upon combined stimulation with PGD2 and TNF-alpha. The synergistic production of MCP-1 and IL-8 by PGD2 was mimicked by dibutyryl cAMP (db-cAMP) and was inhibited by a protein kinase A (PKA) inhibitor. Our findings suggest that activation of the prostanoid DP receptor on THP-1 cells enhances TNF-alpha-induced MCP-1 and IL-8 production via the cAMP/PKA signaling pathway.

Enhancement of mite allergen-induced eosinophil infiltration in the murine airway and local cytokine/chemokine expression by Asian sand dust

Data on the effects of sand dust toward allergic asthma produced by indoor allergens, such as house dust mites, are not currently available. This study was undertaken to clarify the role of Asian sand dust on mite allergen, Dermatophagoides farinae (D. farinae)-induced eosinophilic inflammation in the murine lung, using sand dusts from the Maowusu Desert (Inner Mongolia) (SD-1) and the Tengger Desert (China) (SD-2). ICR mice were intratracheally administered saline; SD-1 alone; SD-2 alone; D. farinae alone; D. farinae + SD-1; and D. farinae + SD-2, 4 times at 2-wk intervals. The two sand dusts enhanced infiltration of eosinophil in the airway, along with goblet-cell proliferation related to D. farinae. The degree of eosinophil infiltration induced with SD-2 was greater than with SD-1. The SD-1, which contained higher amounts of beta-glucan, increased the expression of interferon (IFN)-gamma in bronchoalveolar lavage fluids (BALF) with or without D. farinae, but SD-2 did not. Synergistically or cumulatively elevated levels of interleukin (IL)-5, eotaxin, and monocyte chemotactic protein in BALF related to D. farinae were higher with D. farinae + SD-2 than with D. farinae + SD-1. These results suggest that increased cytokine and chemokines in BALF play an important role in the enhancement of eosinophil infiltration in the airway induced by D. farinae + sand dusts. The reduced eosinophil infiltration in the SD-1-treated mice could be due to suppression of Th-2 cytokine and eotaxin via interferon-gamma induced by microbial materials, such as beta-glucan.

[Eosinophils: structure and functions]

Long considered to be secondary cells characterized mainly by their ability to be recruited to inflammation sites, these cells are now known to release a wide array of cytotoxic mediators. Moreover they participate in immune response regulation by producing Th1 and Th2 cytokines as well as regulatory cytokines and chemokines. This review describes recent findings about their expression of surface molecules, eosinophil mediators, and the role of both in these novel eosinophil functions.

Asian sand dust enhances ovalbumin-induced eosinophil recruitment in the alveoli and airway of mice

Asian sand dust (ASD) containing sulfate (SO4(2-)) reportedly causes adverse respiratory health effects but there is no experimental study showing the effect of ASD toward allergic respiratory diseases. The effects of ASD and ASD plus SO4(2-) toward allergic lung inflammation induced by ovalbumin (OVA) were investigated in this study. ICR mice were administered intratracheally with saline; ASD alone (sample from Shapotou desert); and ASD plus SO4(2-) (ASD-SO4); OVA+ASD; OVA+ASD-SO4. ASD or ASD-SO4 alone caused mild nutrophilic inflammation in the bronchi and alveoli. ASD and ASD-SO4 increased pro-inflammatory mediators, such as Keratinocyte chemoattractant (KC) and macrophage inflammatory protein (MIP)-1 alpha, in bronchoalveolar lavage fluids (BALF). ASD and ASD-SO4 enhanced eosinophil recruitment induced by OVA in the alveoli and in the submucosa of the airway, which has a goblet cell proliferation in the bronchial epithelium. However, a further increase of eosinophils by addition of SO4(2-) was not observed. The two sand dusts synergistically increased interleukin-5 (IL-5) and monocyte chemotactic protein-1 (MCP-1), which were associated with OVA, in BALF. However, the increased levels of IL-5 were lower in the OVA+ASD-SO4 group than in the OVA+ASD group. ASD caused the adjuvant effects to specific-IgG1 production by OVA, but not to specific-IgE. These results suggest that the enhancement of eosinophil recruitment in the lung is mediated by synergistically increased IL-5 and MCP-1. IgG1 antibodies may play an important role in the enhancement of allergic reaction caused by OVA and sand dust. However, extra sulfate may not contribute to an increase of eosinophils.

Cysteinyl leukotrienes induce monocyte chemoattractant protein 1 in human monocytes/macrophages

BACKGROUND

Monocytes/macrophages have a cysteinyl leukotriene 1 (CysLT1) receptor, but its function is poorly understood. Objective To elucidate the biological function of the CysLT1 receptor of human monocytes/macrophages.

METHODS

We examined the production of TNF-alpha, IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, monocyte chemoattractant protein 1 (MCP-1), macrophage colony-stimulating factor (M-CSF), and eotaxin induced by CysLTs (leukotriene (LT)C4, -D4, and -E4) in THP-1 cells, a human monocytic leukaemia cell line, and peripheral blood CD14+ monocytes/macrophages. Moreover, we examined the effect of CysLTs on the expression of beta-chemokine receptor 2B (CCR2B) as the receptor of MCP-1 by Western blot analysis.

RESULTS

ELISA revealed that CysLTs induced MCP-1 in THP-1 cells and peripheral blood CD14+ monocytes/macrophages, but not other cytokines. PCR demonstrated that CysLTs increased MCP-1 mRNA expression in THP-1 cells, and Western blotting showed that CysLTs increased the expression of CCR2B in THP-1 cells. Moreover, we demonstrated that pranlukast, a CysLT1 receptor antagonist, blocked MCP-1 production by CysLTs in THP-1 cells almost completely, and partially inhibited MCP-1 release by CysLTs in peripheral blood CD14+ monocytes/macrophages and CCR2B expression by CysLTs in THP-1 cells.

CONCLUSION

CysLTs induce MCP-1 and increase CCR2B expression in human monocytes/macrophages.

Effect of montelukast on nuclear factor kappaB activation and proinflammatory molecules

BACKGROUND

Montelukast is known as a cysteinyl leukotriene 1 receptor antagonist. However, the action of montelukast in terms of nuclear factor KB (NF-kappaB) activation and the production of proinflammatory molecules is unknown.

OBJECTIVE

To demonstrate the potential anti-inflammatory effect of montelukast.

METHODS

We examined whether montelukast inhibits the activation of NF-kappaB, a transcription factor that regulates the expression of proinflammatory molecules. The inhibitory effects of montelukast on tumor necrosis factor kappa (TNF-kappa)--induced NF-kappaB activation on THP-1 cells, a human monocytic leukemia cell line, were evaluated by flow cytometry, and those on lipopolysaccharide-induced interleukin 1beta (IL-1beta), IL-6, TNF-alpha, and monocyte chemoattractant protein 1 (MCP-1) production in peripheral blood mononuclear cells were evaluated by enzyme-linked immunosorbent assay.

RESULTS

Flow cytometry demonstrated that montelukast inhibited NF-kappaB activation in THP-1 cells in a dose-related manner. Furthermore, 10(-5)M montelukast significantly inhibited lipopolysaccharide-induced IL-6, TNF-alpha, and MCP-1 production in the peripheral blood mononuclear cells of controls and patients with asthma. Lipopolysaccharide-induced IL-1beta production was not inhibited by montelukast.

CONCLUSIONS

These findings suggest that high doses of montelukast modulate the production of IL-6, TNF-alpha, and MCP-1 through the inhibition of NF-kappaB activation. However, the anti-inflammatory effect of montelukast at therapeutic doses in patients with asthma needs to be further investigated.

Interleukin-25–Induced Chemokines and Interleukin-6 Release from Eosinophils Is Mediated by p38 Mitogen-Activated Protein Kinase, c-Jun N-Terminal Kinase, and Nuclear Factor-κB

Interleukin (IL)-25, a novel Th2 cytokine, is capable of amplifying allergic inflammation. We investigated the modulation of nuclear factor (NF)-kappaB and mitogen-activated protein kinases (MAPK) pathways in IL-25-activated eosinophils, the principal effector cells of allergic inflammation, for the in vitro release of chemokines including monocyte chemoattractant protein-1 (MCP-1), IL-8, and macrophage inflammatory protein (MIP)-1alpha, and inflammatory cytokine IL-6. Gene expression of chemokines and IL-6 was evaluated by RT-PCR, and concentrations of chemokines and cytokine were measured by cytokine protein array, cytometric bead array, and enzyme-linked immunosorbent assay. NF-kappaB, c-Jun amino-terminal kinase (JNK), and p38 MAPK activities in eosinophils were assessed by electrophoretic mobility shift assay and Western blot. IL-25 was found to upregulate the gene expression of chemokines MCP-1, MIP-1alpha, and IL-8, and cytokine IL-6, in eosinophils, and to significantly increase the release of the above chemokines and IL-6 from eosinophils. IL-25 could also activate the JNK, p38 MAPK, and NF-kappaB activities of eosinophils, while inhibitor of IkappaB-alpha phosphorylation (BAY11-7082), JNK (SP600125), and p38 MAPK (SB203580) could suppress the release of IL-8, MIP-1alpha, MCP-1, and IL-6. Together, the above results showed that the induction of MCP-1, MIP-1alpha, IL-8, and IL-6 in IL-25-activated eosinophils are regulated by JNK, p38 MAPK, and NF-kappaB pathways.

Pulmonary toxicity induced by intratracheal instillation of Asian yellow dust (Kosa) in mice

Asian yellow dust (Kosa) causes adverse respiratory health effects in humans. The objective of this study was to clarify the lung toxicity of Kosa. ICR mice (5 weeks of age) were administered intratracheally with Kosa samples-two samples from Maowusu desert and Shapotou desert, one sample consisted of Shapotou Kosa plus sulfate, and natural Asian dust (NAD) from the atmosphere of Beijing-at doses of 0.05, 0.10 or 0.20mg/mouse at four weekly intervals. The four Kosa samples tested had similar compositions of minerals and concentrations of elements. Instillation of dust particles caused bronchitis and alveolitis in treated mice. The magnitude of inflammation was much greater in NAD-treated mice than in the other particles tested. Increased neutrophils, lymphocytes or eosinophils in bronchoalveolar lavage fluids (BALF) of treated mice were dose dependent. The number of neutrophils in BALF at the 0.2mg level was parallel to the content of β-glucan in each particle. The numbers of lymphocytes and eosinophils in BALF at the 0.2mg level were parallel to the concentration of SO(4)(2-) in each particle. Pro-inflammatory mediators-such as interleukin (IL)-12, tumor necrosis factor-(TNF)-α, keratinocyte chemoattractant (KC), monocyte chemotactic protein (MCP)-l and macrophage inflammatory protein-(MIP)-lα in BALF-were greater in the treated mice. Specifically, NAD considerably increased pro-inflammatory mediators at a 0.2mg dose. The increased amounts of MlP-lα and TNF-α at 0.2mg dose corresponded to the amount of β-glucan in each particle. The amounts of MCP-l or IL-12 corresponded to the concentration of sulfate (SO(4)(2-)) at a 0.2mg dose. These results suggest that inflammatory lung injury was mediated by β-glucan or SO(4)(2-), which was adsorbed into the particles, via the expression of these pro-inflammatory mediators. The results also suggest that the variations in the magnitude of inflammation of the tested Kosa samples depend on the amounts of these toxic materials.

Heterogeneity of expression of IgA receptors by human, mouse, and rat eosinophils

IgA is the most abundant class of Abs at mucosal surfaces where eosinophils carry out many of their effector functions. Most of the known IgA-mediated functions require interactions with IgA receptors, six of which have been identified in humans. These include the IgA FcR FcalphaRI/CD89 and the receptor for the secretory component, already identified on human eosinophils, the polymeric IgR, the Fcalpha/muR, asialoglycoprotein (ASGP)-R, and transferrin (Tf)R/CD71. In rodents, the existence of IgA receptors on mouse and rat eosinophils remains unclear. We have compared the expression and function of IgA receptors by human, rat, and mouse eosinophils. Our results show that human eosinophils express functional polymeric IgR, ASGP-R, and TfR, in addition to CD89 and the receptor for the secretory component, and that IgA receptors are expressed by rodent eosinophils. Indeed, mouse eosinophils expressed only TfR, whereas rat eosinophils expressed ASGP-R and CD89 mRNA. These results provide a molecular basis for the differences observed between human, rat, and mouse regarding IgA-mediated immunity.

High level expression, activation, and antagonism of CC chemokine receptors CCR2 and CCR3 in Chinese hamster ovary cells

The specificity of leukocyte trafficking in inflammation is controlled by the interactions of chemokines with chemokine receptors. Reliable structure-function studies of chemokine-receptor interactions would benefit from cell lines that express consistent high levels of chemokine receptors. We describe herein two new Chinese hamster ovary (CHO) cell lines in which the genes for chemokine receptors CCR2 and CCR3 have been incorporated into identical positions in the host genome. CCR2 is the primary receptor for the chemokine monocyte chemoattractant protein-1 (MCP-1) whereas CCR3 is the primary receptor for the chemokines eotaxin-1, eotaxin-2 and eotaxin-3. Both receptors are expressed at >5,000,000 copies per cell, substantially higher levels than in previous cell lines, and both are competent for binding and activation by the cognate chemokines for these receptors. Using these cell lines we confirm that eotaxin-1 and eotaxin-3 can act as an agonist and an antagonist, respectively, of CCR2. In addition, we show that eotaxin-2 is an antagonist of CCR2 and MCP-1 is an agonist of CCR3. Comparison of the chemokine sequences reveals several positions that are identical in MCP-1 and eotaxin-1 but different in eotaxin-2 and eotaxin-3, suggesting that these amino acids play a role in CCR2 activation.

Potential role of MCP-1 in endothelial cell tight junction 'opening': signaling via Rho and Rho kinase

The expression of the monocyte chemoattractant protein-1 (MCP-1) receptor CCR2 by brain endothelial cells suggests that MCP-1 may have other functions than purely driving leukocyte migration into brain parenchyma during inflammation. This study examines one of these potential novel roles of MCP-1 regulation of endothelial permeability using primary cultures of mouse brain endothelial cells. MCP-1 induces reorganization of actin cytoskeleton (stress fiber formation) and redistribution of tight junction proteins, ZO-1, ZO-2 occludin and claudin-5, from the Triton X-100-soluble to the Triton X-100-insoluble fractions. These morphological changes are associated with a decrease in transendothelial electrical membrane resistance and an increase in [14C]inulin permeability. MCP-1 did not induce these events in brain endothelial cells prepared from mice genotype CCR2-/-. The Rho kinase inhibitor Y27632 and inhibition of Rho (C3 exoenzyme, and dominant negative mutant of Rho, RhoT19N) prevented MCP-1-induced stress fiber assembly, reorganization of tight junction proteins and alterations in endothelial permeability. In all, this suggests that a small GTPase Rho and Rho kinase have a pivotal role in MCP-1-induced junction disarrangement. These data are the first to strongly suggest that MCP-1, via CCR2 present on brain endothelial cells, contributes to increased brain endothelial permeability.

Concentration-dependent effects of mometasone furoate and dexamethasone on foetal lung fibroblast functions involved in airway inflammation and remodeling

Lung fibroblasts play a key role in the pathogenesis of airway inflammation and remodeling through the release of mediators and the expression of surface molecules connected with cell-cell and cell-extracellular matrix interaction. The aim of the study was to evaluate the inhibitory effect of two corticosteroids, mometasone furoate (MOM) and dexamethasone (DEX), respectively, on a variety of fibroblast functions: DNA synthesis and proliferation, expression of adhesion molecules [intercellular adhesion molecule-1 (ICAM-1, CD54) and hyaluronic cellular adhesion molecule (HCAM, CD44)] and release of chemokines/cytokines [monocyte chemoattractant protein (MCP)-1, eotaxin, interleukin (IL)-6 and transforming growth factor (TGF)-beta]. Cells from a human foetal lung fibroblast cell line (GM 06114) were stimulated with basic fibroblast growth factor (bFGF) or tumour necrosis factor (TNF)-alpha in the presence of different concentrations (0.01-100.0nM) of MOM or DEX. A significant increase in fibroblast DNA synthesis and proliferation was observed when the cells were stimulated with bFGF (p<0.05), whereas TNF-alpha induced a significant upregulation in ICAM-1 expression and in MCP-1, eotaxin and IL-6 release (p<0.05, each comparison). No changes in HCAM expression and in TGF-beta release were observed (p>0.05, each comparison). The addition of MOM or DEX at the beginning of the cell cultures induced a significant downregulation in fibroblast DNA synthesis and proliferation, ICAM-1 and HCAM expression and chemokine/cytokine release (p<0.05, each comparison). At all the concentrations tested, MOM was more effective than DEX in inhibiting ICAM-1 expression and MCP-1 release (p<0.05, each comparison), whereas no potency advantage for MOM was detected in DNA synthesis, cell proliferation, HCAM expression and in eotaxin, IL-6 and TGF-beta release (p>0.05, each comparisons). These results extend the profile of the anti-inflammatory activity of mometasone furoate to lung fibroblast functions involved in airway inflammation and remodeling.

Neuropeptide-induced inhibition of IL-16 release from eosinophils

OBJECTIVES

Eosinophils are prominent inflammatory cells that respond to peripheral neuropeptides in vitro and in vivo. At inflammatory sites, cytokines activate distinct cellular and biochemical pathways that act in a coordinated fashion. We investigated whether peripheral neuropeptides can act as immunomodulators by influencing cytokine release from eosinophils.

METHODS

Human eosinophils were enriched using magnetic cell sorting, and IL-16 levels in supernatants from maintained eosinophils were measured by ELISA. Biological activity of IL-16 was confirmed in lymphocyte chemotaxis assays.

RESULTS

Substance P, vasoactive intestinal polypeptide, calcitonin gene-related peptide and secretoneurin reduced the IL-16 release from eosinophils; this effect was additive to that observed with GM-CSF or IL-5. Decreased IL-16 levels in supernatants resulted in reduced lymphocyte chemotaxis, whereas supernatants derived from SP-treated eosinophils stimulated lymphocyte chemotaxis, even though IL-16 was decreased.

CONCLUSIONS

Results suggest that distinct neuropeptides are able to reduce the number of lymphocytes at inflammatory sites during existing eosinophilia by inhibiting eosinophil IL-16 release, thus attenuating the pro-inflammatory action of lymphocytes and monocytes.

Molecular characterization of an interleukin-4-inducing factor from Schistosoma mansoni eggs

The eggs of the parasitic trematode Schistosoma mansoni are powerful inducers of a T helper type 2 (Th2) immune response and immunoglobulin E (IgE) production. S. mansoni egg extract (SmEA) stimulates human basophils to rapidly release large amounts of interleukin (IL)-4, the key promoter of a Th2 response. Here we show purification and sequence of the IL-4-inducing principle of S. mansoni eggs (IPSE). Stimulation studies with human basophils using SmEA fractions and natural and recombinant IPSE as well as neutralization and immunodepletion studies using antibodies to recombinant IPSE demonstrate that IPSE is the bioactive principle in SmEA leading to activation of basophils and to expression of IL-4 and IL-13. Regarding the mechanism of action, blot analysis showed that IPSE is an IgE-binding factor, suggesting that it becomes effective via cross-linking receptor-bound IgE on basophils. Immunohistology revealed that IPSE is enriched in and secreted from the subshell area of the schistosome egg. We conclude from these data that IPSE may be an important parasite-derived component for skewing the immune response toward Th2.

Advances in mechanisms of allergy

This review summarizes selected "mechanisms of allergy" articles appearing between 2001 and 2002 in the Journal of Allergy and Clinical Immunology (JACI). Papers chosen include those dealing with human eosinophil and basophil biology from life to death, as well as studies with animal models of allergic disease, including knock-out mice, Brown Norway rats, and ovalbumin (OVA)-sensitized and challenged BALB/c mice, that further our understanding of mechanisms of allergic diseases. When appropriate, articles from other journals have been included to supplement the topics being presented.

Differences in airway-inflammation development by house dust mite and diesel exhaust inhalation among mouse strains

Three mouse strains (BALB/c, ICR, and C3H/He) were injected intratracheally with house dust mites (Der f) four times at 2-week intervals during exposure to diesel exhaust (DE) or clean air for 8 weeks. Der f treatment caused eosinophilic inflammation and proliferation of goblet cells in the airways of the three strains. DE + Der f caused a further increase of eosinophils in BALB/c and ICR mice, but not in C3H/He mice. DE + Der f significantly increased interleukin (IL)-5; regulated on activation, normal T cell expressed, and presumably secreted (RANTES); eotaxin, monocyte chemotactic protein-1 (MCP-1); and macrophage-inflammatory protein-1 alpha (MIP-1 alpha) in all three strains. However, the protein of IL-5 decreased more in C3H/He mice treated with DE + Der f than in mice treated with Air + Der f. The levels of IL-5 in lung tissues corresponded to the pathological changes by Der f and/or DE treatment. The levels of MCP-1 and MIP-1 alpha in the three strains corresponded to the accumulation of lymphocytes in the airway. The adjuvant effect of DE on IgG1 production was observed in the ICR and C3H/He mice. These results suggest that the murine strain differences in the production of eosinophilic airway inflammation by DE + Der f is related to differences in local expression of IL-5, eotaxin, and IgG1 production. The enhancing effects of DE exposure may be mediated mainly by local IL-5.

Fibroblast-eosinophil interaction: modulation of adhesion molecules expression and chemokine release by human fetal lung fibroblasts in response to IL-4 and TNF-alpha

In addition to be involved in airway remodelling observed in asthmatic patients, lung fibroblasts may directly contribute to pulmonary inflammation through the release of mediators and through the expression of surface molecules involved in cell-cell interaction. The aim of the study was to evaluate whether two cytokines involved in asthma pathogenesis, IL-4 and TNF-alpha, could modulate the expression of adhesion molecules (VCAM-1 and ICAM-1) and the secretion of chemokines (eotaxin and MCP-1) related to eosinophil recruitment and activation. The constitutive expression of VCAM-1 by unstimulated fibroblasts was over 2-fold lower than that of ICAM-1 (P<0.05). Significant differences were also observed in the release of chemokines by unstimulated fibroblast, the levels of eotaxin being over 17-fold lower than those of MCP-1. Stimulation of the cells with IL-4 or TNF-alpha induced a dose-dependent increase in VCAM-1, while ICAM-1 was overexpressed only in culture stimulated by TNF-alpha (P<0.05) but not in those exposed to IL-4 (P>0.05 each comparison). In contrast, a significant increase in MCP-1 and eotaxin release was observed in the presence of TNF-alpha (P<0.05) but not of IL-4 (P>0.05). These data show that two 'proinflammatory' cytokines, such as IL-4 and TNF-alpha, may have different and complementary effects on functions involved in the cross-talking between fibroblasts and eosinophils.