Mediators Of Allergic Inflammation Research Articles

Carnosic acid inhibits secretion of allergic inflammatory mediators in IgE-activated mast cells via direct regulation of Syk activation

Mast cells are essential regulators of inflammation most recognized for their central role in allergic inflammatory disorders. Signaling via the high-affinity immunoglobulin E (IgE) receptor, FcεRI, leads to rapid degranulation of preformed granules and the sustained release of newly synthesized proinflammatory mediators. Our group recently established rosemary extract as a potent regulator of mast cell functions, attenuating MAPK and NF-κB signaling. Carnosic acid (CA)-a major polyphenolic constituent of rosemary extract-has been shown to exhibit anti-inflammatory effects in other immune cell models, but its role as a potential modulator of mast cell activation is undefined. Therefore, we sought here to determine the modulatory effects of CA in a mast cell model of allergic inflammation. We sensitized bone marrow-derived mast cells with anti-trinitrophenyl IgE and activated with allergen (TNP-BSA) under stem cell factor potentiation, in addition to treatment with CA. Our results indicate that CA significantly inhibits allergen-induced early phase responses including Ca2+ mobilization, ROS production, and subsequent degranulation. We also show CA treatment reduced late phase responses, including the release of all cytokines and chemokines examined following IgE stimulation and corresponding gene expression excepting that of CCL2. Importantly, we determined that CA mediates its inhibitory effects through modulation of tyrosine kinase Syk and downstream effectors TAK1 (Ser412) and Akt (Ser473) as well as NFκB signaling, while phosphorylation of FcεRI (γ chain) and MAPK proteins remained unaltered. These novel findings establish CA as a potent modulator of mast cell activation, warranting further investigation as a putative anti-allergy therapeutic.

The Effect of Nasal Irrigation with Dewandaru (Eugenia Uniflora L) Leaves Ethanol Extract on Il-4 Levels, Thymic Stromal Lymphopoiethin (TSLP) Expression and Expression of H4 Mucosa Receptors of Wistar Rats with Allergic Rhinitis

Nasal irrigation with Dewandaru leaf extract can reduce inflammatory cell infiltration in the nasal mucosa of rats, and is effective in reducing RA symptoms and has an effect no different from topical corticosteroids. This study aims to prove whether nasal irrigation with ethanolic extract of Dewandaru leaves can reduce the infiltration of allergic inflammatory mediators in the nasal mucosa of male white rats of Wistar strain suffering from RA after ovalbumin nasal spray was induced, by assessing IL-4 levels, TSLP expression and H4 receptor expression. The study was conducted with a randomized post test only control group design, using an animal model of allergic rhinitis, involving 34 male white rats of the Wistar strain, divided into 2, namely: 17 treatment groups and 17 control groups. After 4 weeks of exposure, termination and sampling of rat nasal mucosa was performed. Statistical analysis using the independent sample T test showed that the levels of IL-4 in the nasal mucosa of rats and the expression of H4 receptors on the nasal mucosa of rats were significantly lower than in the control group (p<0.05). Meanwhile, the TSLP expression of the nasal mucosa of rats in the treatment group (2.0154) was not significantly different from the control group (2.1891) with p=0.478, possibly associated with less severe damage to the epithelial barrier cells of the nasal mucosa of TSLP-producing in the group control. The ethanolic extract of Dewandaru leaves has the ability to suppress IL-4 cytokine levels through inhibition of the activity of RH4, so it can be used as a supporting therapy for nasal irrigation that can suppress allergic inflammatory mediators in the nasal mucosa of rats.

Agnuside mitigates OVA-LPS induced perturbed lung homeostasis via modulating inflammatory, autophagy, apoptosis-fibrosis response and myeloid lineages in mice model of allergic asthma

Attributes of agnuside, a nontoxic, iridoid glycoside have been advocated for inflammatory disorders. However, information on its efficacy in alleviating allergic asthma largely remain ambiguous and yet to be deciphered. Present study aimed to assess efficacy of agnuside in targeting vicious circle of oxi-inflammation, autophagy and fibrosis, together with investigating its underlying molecular mechanism during OVA-LPS induced allergic asthma. Results revealed that agnuside showed prophylactic effect in assuaging asthmatic lung architecture impairment (p ≤ 0.01) as indicated by suppression of inflammatory cell infiltration, congestion, fibrosis, airway remodeling and alveolar collapse in OVA-LPS sensitized group. Decreased expression level (p ≤ 0.05) of allergic inflammatory mediators such as IgE, Th1/Th2, IL-4/IFN-γ, IL-4/IL-10, chemokines, endopeptidases and TGF-β, Smad2/4, Caspase9/3, connexin 43/50 observed in agnuside treatments. Analysis of redox molecular signaling cascade and autophagic proteins revealed concurrent upregulation in p-NF-κB, p-PI3K, p-Akt, p-p38, p-Stat3 activation, GATA3, LC3B expression and reduction in Bcl2/Bax, Beclin1 and p62 expression in sensitized mice (p ≤ 0.05) which were intensely counteracted by administration of agnuside. Suppression in myeloid cells activation and augmentation (p ≤ 0.001) of Tregs established modulatory attribute of agnuside for innate and adaptive immune response during allergic asthma. Collectively, these outcomes confer prophylactic attribute of agnuside and signify it as promising strategy to thwart allergic asthma.

Цитокины в иммунопатогенезе аллергии

Allergy is characterized by inadequate hyperimmune response to one or several antigens with the properties of allergens. A specific pattern of abnormal synthesis of some cytokines (principal molecular mediators of the initiation, development, and regulation of allergic inflammation) has an important pathogenic role in allergy. In recent years, it is generally accepted that allergic disorders are accounted for by impaired immune regulation resulting from increased imbalanced activation of allergen-specific T helper 2 cell clones. Allergic type of immune response is currently referred to as type 2 immune response which normally provides humoral immunity, anthelmintic protection etc. However, pathological response results in allergy. Studies on immune pathogenesis of allergic disorders have improved our understanding of the role of altered synthesis of some cytokines (key mediators of allergic inflammation). Cytokines involved in the initiation and regulation of allergy are produced by epithelial cells, various subsets of leukocytes, innate lymphoid cells, and allergen-activated T helper cell clones. Analysis of the associations of the changes in immune reactivity and clinical manifestations has established pathogenic heterogeneity and identified asthma phenotypes and endotypes. These findings have provided a basis for more reasonable, successful, and personalized approach to biological anti-cytokine treatment for allergic disorders. KEYWORDS: allergy, cytokines, T helper cell clones, phenotype, asthma, anti-cytokine therapy. FOR CITATION: Simbirtsev A.S. Cytokines and their role in immune pathogenesis of allergy. Russian Medical Inquiry. 2021;5(1):32–37. DOI: 10.32364/2587-6821-2021-5-1-32-37.

Leukotriene mechanisms of allergic enterocolitis pathogenesis in young children

Purpose of the study was to determine the parameters of lipid mediators of allergic inflammation (cysteinyl leukotrienes C4, D4, E4) by enzyme immunoassay in serum, saliva, urine of young children with allergic enterocolitis. Materials and methods. 40 patients aged from 3 months to 3 years (mean age - (19.9 ± 2.7) months) were examined, among them 20 children with allergic enterocolitis, 10 patients with asthma at the acute stage and 10 healthy babies. Clinical, allergological, endoscopic examination and concentrations of cysteinyl leukotrienes (LTB4, LTC4, LTE4) determination in the biological fluids (blood serum, saliva, urine) using the enzyme immunoassay kits (Enzo Life Science, USA) on a Multiskan photometer Plus “Labsystems” were conducted. The obtained data results were processed statistically. Significance of differences was assessed using Student's t-test and Kendall's tau rank correlation analysis. Difference with a p value 0.05), blood and saliva τ = 0.07 (p>0.05), urine and saliva τ = -0.52 (P > 0.05). Conclusions. An increase in cysteinyl leukotrienes concentration in blood serum, urine, saliva was found in young children with allergic enterocolitis in comparison with the control group. The absence of a significant rank correlation between leukotrienes concentration in the blood and urine, blood and saliva, saliva and urine indicates that any biological fluid, in particular saliva or urine, could be selected as a non-invasive method for determination of leukotrienes concentration to monitor the activity of allergic inflammation.

Contribution of the glycosyltransferase FucT-VII to allergic skin inflammation

Abstract The development of E and P selectin ligands on the surface of immune cells requires α1,3 fucosyltransferase FucT-VII, an enzyme encoded by the Fut7 gene. T cell activation and cytokine environments regulate glycosyltransferase expression, eventual glycan formation and cell migration. The T helper 2 (Th2) subset are mediators of allergic inflammation, but the requirement for FucT-VII-dependent migration in allergic inflammation is less clear. In this study we determined if Fut7 expression was required for allergic inflammation in the constitutively active STAT6VT model in which mice are predisposed to a spontaneous inflammatory phenotype similar to that of atopic dermatitis. STAT6VT mice were crossed with Fut7−/− animals and compared for the development of disease and inflammation. Decreased incidence of disease was observed in Fut7−/− STAT6VT mice, compared to STAT6VT mice. Interestingly, if disease did occur in Fut7−/− animals, the inflammation was not attenuated and in some cases was more severe. One factor that impacted disease development was related to offspring who inherited the STAT6VT allele from their maternal parent. The dams would have experienced inflammation throughout pregnancy and might have promoted a mechanism of migration independent of Fut7 gene expression. Together, these data indicate that Fut7 promotes, but is not strictly required for, allergic skin inflammation.

IL-33 meets allergens at the gate

IL-33 is a mediator of allergic inflammation and is localized in mucosal tissues to respond rapidly to environmental insults. These include allergens themselves, which can directly activate IL-33 through their intrinsic proteolytic activity.

Anti-inflammatory effect of wogonin on allergic responses in ovalbumin-induced allergic rhinitis in the mouse.

BackgroundWogonin is commonly used for the treatment of allergic diseases. However, neither its precise effect in preventing allergic rhinitis (AR) nor its mechanism of action are known.ObjectivesIn this study, the effect of wogonin on allergic responses in ovalbumin (OVA) induced AR was investigated in mice.MethodsBALB/c mice were sensitized with intraperitoneal (i.p.) OVA and then challenged intranasally with OVA. Wogonin (10 and 30 mg/kg) was given to the treatment groups, and the effect of wogonin on the release of allergic inflammatory mediators, specifically OVA-specific immunoglobulin E (IgE) and inflammatory cytokines, was explored. Eosinophil infiltration and the levels of interleukin (IL) 5 and IL-13 were measured by immunohistochemistry.ResultsIn mice with AR, wogonin decreased OVA-specific IgE levels in serum, and the levels of the cytokines IL-4, IL-5, IL-13, eotaxin, and RANTES in nasal lavage fluid. Serum levels of IL-4, IL-5, and IL-13 were lower in both groups of wogonin-pretreated mice than in the OVA group. A reduction in eosinophil infiltration of the nasal mucosa and inhibition of the expression of IL-5 and IL-13 were also noted in the treated groups.ConclusionWogonin induced antiallergic effects in a murine model of AR by decreasing the infiltration of eosinophils and levels of T-helper type 2 cytokines. Thus, wogonin merits consideration as a therapeutic agent for treating AR.

Histamine and T helper cytokine–driven epithelial barrier dysfunction in allergic rhinitis

Allergic rhinitis (AR) is characterized by mucosal inflammation, driven by activated immune cells. Mast cells and TH2 cells might decrease epithelial barrier integrity in AR, maintaining a leaky epithelial barrier. We sought to investigate the role of histamine and TH2 cells in driving epithelial barrier dysfunction in AR. Air-liquid interface cultures of primary nasal epithelial cells were used to measure transepithelial electrical resistance, paracellular flux of fluorescein isothiocyanate-dextran 4kDa, and mRNA expression of tight junctions. Nasal secretions were collected from healthy control subjects, AR patients, and idiopathic rhinitis patients and were tested invitro. In addition, the effect of activated TH1 and TH2 cells, mast cells, and neurons was tested invitro. The effect of IL-4, IL-13, IFN-γ, and TNF-α on mucosal permeability was tested invivo. Histamine as well as nasal secretions of AR but not idiopathic rhinitis patients rapidly decreased epithelial barrier integrity invitro. Pretreatment with histamine receptor-1 antagonist, azelastine prevented the early effect of nasal secretions of AR patients on epithelial integrity. Supernatant of activated TH1 and TH2 cells impaired epithelial integrity, while treatment with anti-TNF-α or anti-IL-4Rα monoclonal antibodies restored the TH1- and TH2-induced epithelial barrier dysfunction, respectively. IL-4, IFN-γ, and TNF-α enhanced mucosal permeability in mice. Antagonizing IL-4 prevented mucosal barrier disruption and tight junction downregulation in a mouse model of house dust mite allergic airway inflammation. Our data indicate a key role for allergic inflammatory mediators in modulating nasal epithelial barrier integrity in the pathophysiology in AR.

Inflammatory mediators mediate airway smooth muscle contraction through a G protein-coupled receptor–transmembrane protein 16A–voltage-dependent Ca2+ channel axis and contribute to bronchial hyperresponsiveness in asthma

Allergic inflammation has long been implicated in asthmatic hyperresponsiveness of airway smooth muscle (ASM), but its underlying mechanism remains incompletely understood. Serving as G protein-coupled receptor agonists, several inflammatory mediators can induce membrane depolarization, contract ASM, and augment cholinergic contractile response. We hypothesized that the signal cascade integrating on membrane depolarization by the mediators might involve asthmatic hyperresponsiveness. We sought to investigate the signaling transduction of inflammatory mediators in ASM contraction and assess its contribution in the genesis of hyperresponsiveness. We assessed the capacity of inflammatory mediators to induce depolarization currents by electrophysiological analysis. We analyzed the phenotypes of transmembrane protein 16A (TMEM16A) knockout mice, applied pharmacological reagents, and measured the Ca2+ signal during ASM contraction. To study the role of the depolarization signaling in asthmatic hyperresponsiveness, we measured the synergistic contraction by methacholine and inflammatory mediators both exvivo and in an ovalbumin-induced mouse model. Inflammatory mediators, such as 5-hydroxytryptamin, histamine, U46619, and leukotriene D4, are capable of inducing Ca2+-activated Cl- currents in ASM cells, and these currents are mediated by TMEM16A. Acombination of multiple analysis revealed that a G protein-coupled receptor-TMEM16A-voltage-dependent Ca2+ channel signaling axis was required for ASM contraction induced by inflammatory mediators. Block of TMEM16A activity may significantly inhibit the synergistic contraction of acetylcholine and the mediators and hence reduces hypersensitivity. A G protein-coupled receptor-TMEM16A-voltage-dependent Ca2+ channel axis contributes to inflammatory mediator-induced ASM contraction and synergistically activated TMEM16A by allergic inflammatory mediators with cholinergic stimuli.

MiR-122-SOCS1-JAK2 axis regulates allergic inflammation and allergic inflammation-promoted cellular interactions

The regulatory role of suppressor of cytokine signaling 1 (SOCS1) in inflammation has been reported. However, its role in allergic inflammation has not been previously reported. SOCS1 mediated in vitro and in vivo allergic inflammation. Histone deacetylase-3 (HDAC3), a mediator of allergic inflammation, interacted with SOCS1, and miR-384 inhibitor, a positive regulator of HDAC3, induced features of allergic inflammation in an SOCS1-dependent manner. miRNA array analysis showed that the expression of miR-122 was decreased by antigen-stimulation. TargetScan analysis predicted the binding of miR-122 to the 3′-UTR of SOCS1. miR-122 inhibitor induced in vitro and in vivo allergic features in SOCS1-dependent manner. SOCS1 was necessary for allergic inflammation-promoted enhanced tumorigenic and metastatic potential of cancer cells. SOCS1 and miR-122 regulated cellular interactions involving cancer cells, mast cells and macrophages during allergic inflammation. SOCS1 mimetic peptide, D-T-H-F-R-T-F-R-S-H-S-D-Y-R-R-I, inhibited in vitro and in vivo allergic inflammation, allergic inflammation-promoted enhanced tumorigenic and metastatic potential of cancer cells, and cellular interactions during allergic inflammation. Janus kinase 2 (JAK2) exhibited binding to SOCS1 mimetic peptide and mediated allergic inflammation. Transforming growth factor- Δ1 (TGF-Δ1) was decreased during allergic inflammation and showed an anti-allergic effect. SOCS1 and JAK2 regulated the production of anti-allergic TGF-Δ1. Taken together, our results show that miR-122-SOCS1 feedback loop can be employed as a target for the development of anti-allergic and anti-cancer drugs.

NEW APPROACHES TO THE DIAGNOSIS OF ATOPIC DERMATITIS IN CHILDREN

Atopic dermatitis (AD) takes special place in the structure of allergic diseases as it is one of the most prevalent and very first allergic manifestation, it often transforms into other allergic forms, decreases children’s life quality independent of the age and also needs long term and staged treatment. Purpose of work is to establish the status of immune status parameters and mediators of allergic inflammation and to assess the diagnostic capabilities of dermatoscopy and ultrasound examination of the skin in children with atopic dermatitis. Parameters of cellular and humoral immunnity, cytokine status, inflammatory mediators, morphological features of skin changes according to results of dermatoscopy and ultrasound examination were investigated in 128 children with atopic dermatitis aged from 1 to 18 years. Assessment of clinical course’s severity of atopic dermatitis was conducted by semiquantitative method using SCORAD index. In this article presents the results of immunological examination in children with AD and in healthy children aged from 1 to 18 years. Changes of parameters of cellular, humoral immunity, cytokine status and serum immunoglobulins dependent on severity of clinical course were found in children with atopic dermatitis. Atopic dermatitis is a chronic disease with very polymorphic manifestations in skin. According to the results we can conclude about presence of several dermatoscopy variants of skin damage on background of atopic dermatitis. In the study of echograms of skin areas affected by atopic dermatitis was noted thickening of all layers of skin, presence of hypoechoic wide band between the epidermis and the derma, diffuse decrease of derma echogenicity. Immunogram, dermatoscopy and ultrasound diagnostic of skin can be used in diagnostic process for verification and clarification of clinical diagnosis, evaluating of treatment effectiveness and examination of medical services quality.

Xinqin exhibits the anti-allergic effect through the JAK2/STAT5 signaling pathway

Ethnopharmacological relevanceXinqin, a polyherbal medicine, is an important traditional Chinese herbal formula used in traditional oriental medicine for treatment of allergic rhinitis (AR). The formula is based on the Chinese Pharmacopoeia Aim of the studyPreviously, Xinqin exhibited potent anti-allergic effect in a guinea pig model of AR. In this study, we explored the molecular mechanism of the anti-allergic effect mediated by Xinqin. Materials and methodsAR was induced in guinea pigs (Hartley) with toluene-2, 4-diisocyanate (TDI) in vivo and in HMC-1 mast cells with A23187/phorbol 12-myristate-13-acetate (PMA) in vitro. The releases of allergic inflammatory mediators such as histamine, leukotriene (LT) D4, immunoglobulin (Ig) E, TNF-α, and IL-6 were analyzed for allergy. The mast cell degranulation was displayed in HMC-1 mast cells. The activities of janus protein kinase 2 (JAK2), signal transduction and activator of transcription 5 (STAT5) and suppressor of cytokine signaling 3 (SOCS3) were evaluated by Western blot. ResultsTreatment with Xinqin resulted in AR symptoms and decreases in levels of histamine, LTD4, IgE, TNF-α, and IL-6 in serum of guinea pig model of AR and in A23187/PMA-stimulated HMC-1 mast cells. Treatment with Xinqin also inhibited cell degranulation in A23187/PMA-stimulated HMC-1 mast cells. The JAK2/STAT5 signaling pathway could play an important role in the anti-allergic activity mediated by Xinqin. ConclusionsXinqin exerts the anti-allergic effect by modulating mast cell-mediated allergic responses by down-regulating JAK2/STAT5 signaling pathway. Results from this study provide a mechanistic basis for the application of Xinqin in the treatment of AR.

Resveratrol preferentially inhibits IgE-dependent PGD2 biosynthesis but enhances TNF production from human skin mast cells

BackgroundResveratrol, a natural polyphenol found in the skin of red grapes, is reported to have anti-inflammatory properties including protective effects against aging. Consequently, Resveratrol is a common nutritional supplement and additive in non-prescription lotions and creams marketed as anti-aging products. Studies in mice and with mouse bone marrow-derived mast cells (BMMCs) have indicated anti-allergic effects of Resveratrol. However, the effects of Resveratrol on human primary mast cells have not been reported. MethodsHuman mast cells were isolated and purified from normal skin tissue of different donors. The effect of Resveratrol on IgE-dependent release of allergic inflammatory mediators was determined using various immunoassays, Western blotting, and quantitative real-time PCR. ResultsResveratrol at low concentrations (≤10μM) inhibited PGD2 biosynthesis but not degranulation. Accordingly, COX-2 expression was inhibited but phosphorylation of Syk, Akt, p38, and p42/44 (ERKs) remained intact. Surprisingly, TNF production was significantly enhanced with Resveratrol. At a high concentration (100μM), Resveratrol significantly inhibited all parameters analyzed except Syk phosphorylation. ConclusionsHere, we show that Resveratrol at low concentrations exerts its anti-inflammatory properties by preferentially targeting the arachidonic acid pathway. We also demonstrate a previously unrecognized pro-inflammatory effect of Resveratrol — the enhancement of TNF production from human mature mast cells following IgE-dependent activation. General significanceThese findings suggest that Resveratrol as a therapeutic agent could inhibit PGD2-mediated inflammation but would be ineffective against histamine-mediated allergic reactions. However, Resveratrol could potentially exacerbate or promote allergic inflammation by enhancing IgE-dependent TNF production from mast cells in human skin.

Anti-inflammatory effect of curcumin on mast cell-mediated allergic responses in ovalbumin-induced allergic rhinitis mouse

Curcumin has commonly been used for the treatment of various allergic diseases. However, its precise anti-allergic rhinitis effect and mechanism remain unknown. In the present study, the effect of curcumin on allergic responses in ovalbumin (OVA)-induced allergic rhinitis mouse was investigated. We explored the effect of curcumin on the release of allergic inflammatory mediators, such as histamine, OVA-specific IgE, and inflammatory cytokines. Also, we found that curcumin improved rhinitis symptoms, inhibited the histopathological changes of nasal mucosa, and decreased the serum levels of histamine, OVA-specific IgE and TNF-α in OVA-induced allergic rhinitis mice. In addition, curcumin suppressed the production of inflammatory cytokines, such as TNF-α, IL-1β, IL-6 and IL-8. Moreover, curcumin significantly inhibited PMA-induced p-ERK, p-p38, p-JNK, p-Iκ-Bα and NF-κB. These findings suggest that curcumin has an anti-allergic effect through modulating mast cell-mediated allergic responses in allergic rhinitis, at least partly by inhibiting MAPK/NF-κB pathway.

CHARACTERIZATION OF VEGETATIVE CHANGES IN BRONCHIAL ASTHMA OF VARIOUS SEVERITIES IN CHILDREN

This article presents a study of the state of vegetative balance and prognostic possibilities of quantitative parameters of functional activity of VNS to estimate a state of bodily adaptive reserves in children with severe BA. Bronchial asthma, being one of the most common chronic diseases in childhood, requires further research into predisposing and causally-significant factors, mechanisms of pathogenesis and peculiarities of a clinical course, improvement of methods of diagnostics, treatment, and prevention. Great importance in the development of bronchial asthma in children is given to genetically-fixed functional insufficiency of barrier tissues of the respiratory system, increased ability to synthesize allergic antibodies and produce certain cytokines, high bronchopulmonary sensitivity to mediators of allergic inflammation, lowered sensitivity of 3g-adrenoreceptors to endogenous catecholamins, changes in immunologic responsiveness, and disorder of neuroendocrinal regulation of immune responses. Implementation of genetic predisposition to bronchial asthma development is promoted by influence of adverse environmental factors.

15,16-Dihydrotanshinone I suppresses IgE-Ag stimulated mouse bone marrow-derived mast cell activation by inhibiting Syk kinase

Ethnopharmacological relevance15,16-Dihydrotanshinone I (DHT-I), isolated from the dried root of Salvia miltiorrhiza Bung, which is traditionally used to treat cardiovascular and inflammatory diseases agent in Chinese medicine. DHT-I has been reported to have a broad range of biological activities, including antibacterial activity, and has been used to treat circulatory disorders, hepatitis, inflammation, cancer, and neurodegenerative diseases. Aim of the studyThe aim of this study was to evaluate the anti-allergic inflammatory effects of DHT-I on degranulation and on the generation of eicosanoids, such as, prostaglandin D2 (PGD2) and leukotriene C4 (LTC4), in IgE/Ag-stimulated bone marrow-derived mast cells (BMMCs). Materials and methodsThe anti-allergic inflammatory activity of DHT-I was evaluated using BMMCs. The effects of DHT-I on mast cell activation were investigated by following degranulation and eicosanoid generation using ELISA and immunoblotting and immunoprecipitation techniques. ResultsDHT-I at a concentration of 20μM markedly inhibited degranulation and the generation of PGD2 and LTC4 in IgE/Ag-stimulated BMMCs (about 90% inhibitions, respectively). Analyses of FcεRI-mediated signaling pathways demonstrated that DHT-I inhibited the phosphorylations of spleen tyrosine kinase (Syk) and linker for activation of T cells (LAT), and inhibited downstream signaling process, including [Ca2+]i mobilization induced by the phosphorylation of phospholipase Cγ1 (PLCγ1), and the activations of mitogen-activated protein kinases (MAPKs) and the Akt-nuclear factor-κB (NF-κB) pathway. ConclusionsDHT-1 inhibits the release of allergic inflammatory mediators from IgE/Ag-stimulated mast cells by suppressing a FcεRI-mediated Syk-dependent signal pathway. This result suggests DHT-I offers a novel developmental basis for drugs targeting allergic inflammatory diseases.

Blockage of Eosinopoiesis by IL-17A Is Prevented by Cytokine and Lipid Mediators of Allergic Inflammation.

Interleukin- (IL-) 17A, a pleiotropic mediator of inflammation and autoimmunity, potently stimulates bone-marrow neutrophil production. To explore IL-17A effects on eosinopoiesis, we cultured bone-marrow from wild-type mice, or mutants lacking inducible nitric oxide synthase (iNOS−/−), CD95 (lpr), IL-17RA, or IL-4, with IL-5, alone or associated with IL-17A. Synergisms between IL-17A-activated, NO-dependent, and NO-independent mechanisms and antagonisms between IL-17A and proallergic factors were further examined. While IL-17A (0.1–10 ng/mL) had no IL-5-independent effect on eosinopoiesis, it dose-dependently suppressed IL-5-induced eosinophil differentiation, by acting during the initial 24 hours. Its effectiveness was abolished by caspase inhibitor, zVAD-fmk. The effect of IL-17A (0.1–1 ng/mL) was sensitive to the iNOS-selective inhibitor aminoguanidine and undetectable in iNOS−/− bone-marrow. By contrast, a higher IL-17A concentration (10 ng/mL) retained significant suppressive effect in both conditions, unmasking a high-end iNOS-independent mechanism. Lower IL-17A concentrations synergized with NO donor nitroprusside. Eosinopoiesis suppression by IL-17A was (a) undetectable in bone-marrow lacking IL-17RA or CD95 and (b) actively prevented by LTD4, LTC4, IL-13, and eotaxin. Sensitivity to IL-17A was increased in bone-marrow lacking IL-4; adding IL-4 to the cultures restored IL-5 responses to control levels. Therefore, effects of both IL-17A and proallergic factors are transduced by the iNOS-CD95 pathway in isolated bone-marrow.

Britanin Suppresses IgE/Ag-Induced Mast Cell Activation by Inhibiting the Syk Pathway.

The aim of this study was to determine whether britanin, isolated from the flowers of Inula japonica (Inulae Flos), modulates the generation of allergic inflammatory mediators in activated mast cells. To understand the biological activity of britanin, the authors investigated its effects on the generation of prostaglandin D2 (PGD2), leukotriene C4 (LTC4), and degranulation in IgE/Ag-induced bone marrow-derived mast cells (BMMCs). Britanin dose dependently inhibited degranulation and the generations of PGD2 and LTC4 in BMMCs. Biochemical analyses of IgE/Ag-mediated signaling pathways demonstrated that britanin suppressed the phosphorylation of Syk kinase and multiple downstream signaling processes, including phospholipase Cγ1 (PLCγ1)-mediated calcium influx, the activation of mitogen-activated protein kinases (MAPKs; extracellular signal-regulated kinase 1/2, c-Jun NH2-terminal kinase and p38), and the nuclear factor-κB (NF-κB) pathway. Taken together, the findings of this study suggest britanin suppresses degranulation and eicosanoid generation by inhibiting the Syk-dependent pathway and britanin might be useful for the treatment of allergic inflammatory diseases.

Histamine induces human lung fibroblast-mediated collagen gel contraction via histamine H1 receptor

ABSTRACTBackground: Airway remodeling is implicated in irreversible airflow limitation of refractory asthma, which includes increased smooth muscle mass and subepithelial fibrosis. Activated fibroblasts acquire contractile phenotype to participate in tissue contraction and structural alteration of extracellular matrices. Histamine is a potent mediator of allergic inflammation, substantially involved in asthmatic pathophysiology. Objective: We hypothesized that histamine might play a role in airway remodeling, and investigated its effect on fibroblast-mediated collagen gel contraction. Methods: Fibroblast-mediated collagen gel contraction was studied. Histamine's regulation of collagen gel contraction was characterized by using specific histamine-receptor antagonists, an IP3 receptor antagonist and a PKC inhibitor. Results: Histamine induced contraction of collagen gels embedded with human lung fibroblasts, in a time-dependent manner, and at the concentration more than 10−6 M, both in four primary cultured adult lung fibroblasts and three fetal lung fibroblast cell lines. This effect was attenuated by H1 receptor antagonist, whereas those for H2 to H4 receptors failed to show an inhibitory effect. Furthermore, IP3 receptor-mediated Ca2+ mobilization was implicated in histamine's action on collagen gel contraction. Conclusions: Our results suggest that histamine is involved in airway remodeling through its action on lung fibroblasts, and antihistamine drugs, especially H1 receptor antagonists, might be potentially beneficial for a subset of asthmatic patients.