Cell-mediated Allergic Responses Research Articles

NFATc1 fosters allergic contact dermatitis responses by enhancing the induction of IL-17-producing CD8 cells.

A plethora of data supports a major role of CD4+ and CD8+ T lymphocytes for the initiation, progression and maintenance of allergic contact dermatitis (ACD). However, in-depth understanding of the molecular mechanisms is still limited. NFATc1 plays an essential role in T cell activation. We therefore investigated its impact on contact hypersensitivity (CHS), the mouse model for ACD. The CHS response to 2,4,6-trinitrochlorobenzene (TNCB) was diminished in Nfatc1fl/flxCd4-cre mice (Nfatc1-/-) as compared to wild-type (WT) animals and associated with a lower percentage of interleukin (IL) 17-producing CD8+ T (Tc17) cells in both inflamed skin and draining lymph nodes (dLN). In vitro Tc17 polarization assays revealed that Nfatc1-/- CD8+ T cells have a reduced capacity to polarize into Tc17 cells. Applying single-cell RNA sequencing, we realized that NFATc1 controls the T cell differentiation fate. In the absence of NFATc1, CD8+ T cells favour the development of Interferon (IFN)-γ-secreting CD8+ T (Tc1) lymphocytes while in its presence they turn into Tc17 cells. Finally, the adoptive transfer of TNCB-sensitized WT CD8+ T cells restored the CHS response in naïve Nfatc1-/-mice. Our data demonstrate that NFATc1 contributes to the development of Tc17 cells and might present a promising target to alleviate CD8+ T cell-mediated allergic responses.

Se-rich tea polysaccharide extracted by high hydrostatic pressure attenuated anaphylaxis by improving gut microbiota and metabolic regulation

Selenium-rich tea polysaccharides (Se-TPS) were extracted via high hydrostatic pressure technology with a pressure of 400 MPa (200–500 MPa) for 10 min (3–20 min) at a material-to-solvent ratio of 1:40 (1:20–1:50). Subsequently, Se-TPS1–4 were isolated and purified, with Se-TPS3–4 as the main components. A spectral analysis proved that Se, which has antioxidant activity, existed. An in vitro study found that among Se-TPS, Se-TPS3–4 attenuated the release of β-hexosaminidase, histamine, and interleukin (IL)-4. Furthermore, in vivo experiments revealed that treatment with Se-TPS downregulated IL-4 levels and upregulated TGF-β and interferon-γ levels to improve imbalanced Th1/Th2 immunity in tropomyosin-sensitized mice. Moreover, Se-TPS promoted Lactobacillus and norank_f_Muribaculaceaek growth and upregulated metabolites such as genipin and coniferyl alcohol. Overall, these results showed the strong anti-allergy potential of Se-TPS by regulating mast cell-mediated allergic inflammatory responses and microbiota regulation, highlighting the potential of Se-TPS as a novel therapeutic agent to regulate allergy-associated metabolic disorders.

Drug repositioning of anti-microbial agent nifuratel to treat mast cell-mediated allergic responses.

Objectives: Our objective was to assess the effects and mechanisms of nifuratel on IgE-mediated mast cell (MC) degranulation and anaphylaxis in both in vitro and in vivo settings.Methods: The anti-allergic activity of nifuratel was evaluated in mast cell cultures and the passive cutaneous anaphylaxis (PCA) model. The effects of nifuratel on signaling pathways stimulated by antigen in mast cells were measured by immunoblotting, immunoprecipitation, in vitro protein tyrosine kinase assay, and other molecular biological methods.Results: Nifuratel reversibly inhibited antigen-induced degranulation of MCs (IC50, approximately 0.34μM for RBL-2H3 cells; approximately 0.94μM for BMMCs) and suppressed the secretion of inflammatory cytokines IL-4 (IC50, approximately 0.74μM) and TNF-α (IC50, approximately 0.48μM). Mechanism studies showed that nifuratel inhibited the phosphorylation of Syk by antigen via the inhibition of recruitment of cytosolic Syk to the ɣ subunit of FcεRI, and decreased the activation of Syk downstream signaling proteins LAT, Akt, and MAPKs. Finally, nifuratel dose-dependently suppressed the IgE-mediated passive cutaneous anaphylaxis in mice (ED50, approximately 22mg/kg).Conclusion: Our findings suggest that nifuratel inhibits pathways essential for the activation of mast cells to suppress anaphylaxis, thereby indicating that the anti-microbial drug, nifuratel, could be a potential drug candidate for IgE-mediated allergic disorders.

DJ-1 governs airway progenitor cell/eosinophil interactions to promote allergic inflammation

DJ-1 is an antioxidant protein known to regulate mast cell-mediated allergic response, but its role in airway eosinophilic interactions and allergic inflammation is not known. The aim of this study was to investigate the role of DJ-1 in airway eosinophilic inflammation invitro and invivo. Ovalbumin-induced airway allergic inflammation was established in mice. ELISA was adopted to analyze DJ-1 and cytokine levels in mouse bronchoalveolar lavage fluid. Transcriptional profiling of mouse lung tissues was conducted by single-cell RNA-sequencing technology. The role of DJ-1 in the differentiation of airway progenitor cells into goblet cells was examined by organoid cultures, immunofluorescence staining, quantitative PCR, and cell transplantation in normal, DJ-1 knockout (KO), or conditional DJ-1 KO mice. This study observed that DJ-1 was increased in the lung tissues of ovalbumin-sensitized and challenged mice. DJ-1 KO mice exhibited reduced airway eosinophil infiltration and goblet cell differentiation. Mechanistically, we discovered that eosinophil-club cell interactions are reduced in the absence of DJ-1. Organoid cultures indicated that eosinophils impair the proliferative potential of club cells. Intratracheal transplantation of DJ-1-deficient eosinophils suppresses airway goblet cell differentiation. Loss of DJ-1 inhibits the metabolism of arachidonic acid into cysteinyl leukotrienes in eosinophils while these secreted metabolites promote airway goblet cell fate in organoid cultures and invivo. DJ-1-mediated interactions between airway epithelial progenitor cells and immune cells are essential in controlling airway goblet cell metaplasia and eosinophilia. Blockade of the DJ-1 pathway is protective against airway allergic inflammation.

Ginger-derived compounds exert in vivo and in vitro anti-asthmatic effects by inhibiting the T-helper 2 cell-mediated allergic response.

6-Shogaol (SHO) and 6-gingerol (GIN), naturally derived compounds of ginger (Zingiber officinale Roscoe), have been found to have anti-allergic effects on dermatitis-like skin lesions and rhinitis. Although SHO and GIN have demonstrated a potential in various inflammatory diseases, their efficacy and mechanism in asthma have not been largely examined. Therefore, the present study demonstrated the anti-asthmatic effects of SHO and GIN on the T-helper (Th) 2 cell-mediated allergic response pathway in an ovalbumin (OVA)-induced asthma mouse model. The asthma mouse model was established with an intraperitoneal (i.p.) injection of 50 µg OVA and 1 mg aluminum hydroxide with or without an i.p. injection of SHO and GIN (10 mg/kg) before treatment with OVA. In addition, the current study assessed mast cell degranulation in antigen-stimulated RBL-2H3 cells under different treatment conditions (SHO or GIN at 0, 10, 25, 50 and 100 nM) and determined the mRNA and protein levels of anti-oxidative enzymes [superoxide dismutase (SOD)1, SOD2, glutathione peroxidase-1/2, catalase] in lung tissues. SHO and GIN inhibited eosinophilia in the bronchoalveolar lavage fluids and H&E-stained lung tissues. Both factors also decreased mucus production in periodic acid-Schiff-stained lung tissues and the levels of Th2 cytokines in these tissues. GIN attenuated oxidative stress by upregulating the expression levels of anti-oxidative proteins. In an in vitro experiment, the degranulation of RBL-2H3 rat mast cells was significantly decreased. It was found that SHO and GIN effectively suppressed the allergic response in the mouse model by inhibiting eosinophilia and Th2 cytokine production. Collectively, it was suggested that SHO can inhibit lung inflammation by attenuating the Th2 cell-mediated allergic response signals, and that GIN can inhibit lung inflammation and epithelial cell remodeling by repressing oxidative stress. Therefore, SHO and GIN could be used therapeutically for allergic and eosinophilic asthma.

The inhibition of pectin oligosaccharides on degranulation of RBL-2H3 cells from apple pectin with high hydrostatic pressure assisted enzyme treatment

The conditions for the preparation of pectic oligosaccharides (POS) by high hydrostatic pressure-assisted enzymatic (E-HHP) method were explored. The optimal conditions consisted of the pressure of 350 MPa for 20 min, and enzymolysis for 60 min with 0.011 U/mL enzyme. The products were isolated by ion exchange chromatography, galacturonic acid, di- and tri-galacturonides (Tri-GalA) with high purity were obtained. Additionally, the effects of POS on activation and degranulation of RBL-2H3 mast cells were investigated. It was found that Tri-GalA and POS could attenuate the release of β-hexosaminidase and histamine, reduce the production of IL-4 and inhibit the extracellular Ca2+ influx of RBL-2H3 cells. Notably, 150 μg/mL POS significantly alleviated the IgE-mediated allergic reaction of RBL-2H3 cells. These results indicate that POS could be used as an inhibitor in regulating mast cell-mediated allergic inflammatory responses.

Anti-atopic effect of Viola yedoensis ethanol extract against 2,4-dinitrochlorobenzene-induced atopic dermatitis-like skin dysfunction

Ethnopharmacological relevanceViola yedoensis Makiho (VY, Violaceae) is a well-known medicinal herb in Chinese medicine, which is traditionally used to treat inflammation-related disorders, including allergic skin reactions. Although studies have uncovered its anti-inflammatory effects and corresponding bioactive constituents, the exact mechanism of action is still unclear in treating allergic skin reactions. ObjectiveAtopic dermatitis (AD) is a chronic inflammatory skin disease characterized by severe pruritus, dry, edema and inflamed skin. It affects people's quality of life seriously and causes huge economic losses to society. This study proposes VY as a possible remedy for atopic dermatitis since its traditional usage and superior anti-inflammatory effects. Materials and methodsAtopic dermatitis-like skin lesion was induced by topical application of 2,4-dinitrochlorobenzene (DNCB) in ICR mice. After treatment with Viola yedoensis Makiho ethanol extract (VYE) or dexamethasone (positive control) for 3 weeks, skin pathological observation and the molecular biological index were performed for therapeutic evaluation, including visual inspection in the change of the stimulated skin, scar formation, pathological morphology by hematoxylin and eosin (HE) staining, the measurement of interleukin IL-1β, IL-6 and tumor necrosis factor-alpha (TNF-α) levels in serum as well as spleen index. The expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) were analyzed by western blot. The ratio of CD4+/CD8+ T lymphocyte in the spleen was detected by flow cytometry. Meanwhile, immunohistochemistry staining for CD68 identified the number of activated macrophages in skin lesions. Additionally, a reliable ultrahigh-performance liquid chromatography coupled with a Q exactive hybrid quadrupole-orbitrap mass spectrometry (UHPLC-Q-Orbitrap-MS) method was established for the systematic identification and characterization of main components in VYE. ResultsVYE alleviated DNCB-stimulated AD-like lesions symptoms as evidenced by a significant decrease in hypertrophy, hyperkeratosis, and infiltration of inflammatory cells in dorsal skin. The levels of IL-1β, IL-6, and TNF-α in serum were suppressed in mice treated with VYE as compared to the DNCB-induced model group. Also, the administration of VYE reduced the ratio of CD4+/CD8+ T lymphocyte in the spleen and the number of activated macrophages stimulated by DNCB. Besides, the expression of iNOS and COX-2 were down-regulated in the dorsal skin. ConclusionsVYE showed therapeutic effects on atopic dermatitis in DNCB-induced AD-like lesion mouse models by inhibiting the T cell-mediated allergic immune response. Our results indicated that VY could act as a potential remedy for atopic dermatitis.

Protein Disulfide Isomerases Regulate IgE-Mediated Mast Cell Responses and Their Inhibition Confers Protective Effects During Food Allergy.

The thiol isomerase, protein disulfide isomerase (PDI), plays important intracellular roles during protein folding, maintaining cellular function and viability. Recent studies suggest novel roles for extracellular cell surface PDI in enhancing cellular activation and promoting their function. Moreover, a number of food-derived substances have been shown to regulate cellular PDI activity and alter disease progression. We hypothesized that PDI may have similar roles during mast cell-mediated allergic responses and examined its effects on IgE-induced mast cell activity during cell culture and food allergy. Mast cells were activated via IgE and antigen and the effects of PDI inhibition on mast cell activation were assessed. The effects of PDI blockade in vivo were examined by treating mice with the irreversible PDI inhibitor, PACMA-31, in an ovalbumin-induced model of food allergy. The role of dietary PDI modulators was investigated using various dietary compounds including curcumin and quercetin-3-rutinoside (rutin). PDI expression was observed on resting mast cell surfaces, intracellularly, and in the intestines of allergic mice. Furthermore, enhanced secretion of extracellular PDI was observed on mast cell membranes during IgE and antigen activation. Insulin turbidimetric assays demonstrated that curcumin is a potent PDI inhibitor and pre-treatment of mast cells with curcumin or established PDI inhibitors such as bacitracin, rutin or PACMA-31, resulted in the suppression of IgE-mediated activation and the secretion of various cytokines. This was accompanied by decreased mast cell proliferation, FcεRI expression, and mast cell degranulation. Similarly, treatment of allergic BALB/c mice with PACMA-31 attenuated the development of food allergy resulting in decreased allergic diarrhea, mast cell activation, and fewer intestinal mast cells. The production of TH2-specific cytokines was also suppressed. Our observations suggest that PDI catalytic activity is essential in the regulation of mast cell activation, and that its blockade may benefit patients with allergic inflammation.

Imperatorin Relieved Ulcerative Colitis by Regulating the Nrf-2/ARE/HO-1 Pathway in Rats.

Ulcerative colitis is a common intestinal inflammatory disease. Imperatorin (IMP) has been reported to alleviate mast cell-mediated allergic responses by suppressing the expression of Nrf-2, ARE, and HO-1. However, whether IMP can relieve ulcerative colitis by regulating Nrf-2/ARE/HO-1 pathway is unclear. Thus, this study aims to investigate the effect of IMP on ulcerative colitis in rats and elucidate the potential mechanism. In our study, rats were treated with 2,4,6-trinitro-benzenesulfonic acid (TNBS) to induce the animal model of ulcerative colitis. Next, these rats were treated with diverse doses of IMP (15mg/kg, 30mg/kg, and 60mg/kg) and sacrificed at different time points (3days, 7days, and 14days). The levels of inflammatory factors (TNF-α and IL-6) in colon tissues were detected with ELISA kits. H&E staining was performed to observe the pathologic changes of the colon tissues. The expression of Nrf-2, ARE, and HO-1 in colon tissues was determined with the immunofluorescence and Western blotting. The results showed that application of IMP alleviated the symptoms of ulcerative colitis and inhibited the secretion of TNF-α and IL-6. Besides, treatment of IMP promoted the expression of Nrf-2, ARE, and HO-1 in the early stage of this disease (the third day), but suppressed the expression of Nrf-2, ARE, and HO-1 in the advanced stage of the ulcerative colitis (the fourteenth day). Collectively, IMP relieved the symptoms of ulcerative colitis by regulating the Nrf-2/ARE/HO-1 pathway, which might provide a new therapeutic drug to support the clinical treatment of ulcerative colitis.

Oleanolic acid protects against mast cell-mediated allergic responses by suppressing Akt/NF-κB and STAT1 activation

BackgroundOleanolic acid (OA) is an active compound found in a variety of medicinal herbs and plants. Though OA has been widely attributed with a variety of biological activities, studies focused on its anti-allergic inflammation properties are insufficient. PurposeGiven the rapid increase in allergic diseases and the lack of fundamental treatment options, this study aimed to find a safe and effective therapy for allergic disorders. MethodsWe evaluated the inhibitory effect of OA on allergic inflammatory response and the possible mechanisms underlying the effect using phorbol-12-myristate 13-acetate plus calcium ionophore A23187 (PMACI)-stimulated human mast cell (HMC)-1, and a mouse model of compound 48/80-induced anaphylactic shock. ResultsOA suppressed pro-inflammatory cytokine expressions in PMACI-induced HMC-1 cells by inhibiting activation of the Akt, p38 mitogen-activated protein kinase (MAPK), nuclear factor-κB (NF-κB), and signal transducer and activator of transcription (STAT) 1 signaling pathways. Moreover, OA showed a protective effect against compound 48/80-induced anaphylactic shock through inhibition of histamine release and immunoglobulin E level via regulation of NF-κB and STAT1 activation. ConclusionThe results showed that OA suppressed mast cell-mediated allergic response by transcriptional regulation. We suggest that OA has potential effect against allergic inflammatory disorders, including anaphylaxis, and might be a useful therapeutic agent for allergic disease.

Wheat Bran Extract Regulates Mast Cell-Mediated Allergic Responses In Vitro and In Vivo.

In the present study the effects and molecular mechanisms of wheat bran (WB), the hard outer layer of the wheat kernel used in food ingredients, on mast cell-mediated allergic responses in vitro and in vivo were investigated. The water extract of WB inhibited degranulation and expression of allergic and inflammatory mediators such as tumor necrosis factor-α, cyclooxygenase-2 and inducible nitric oxide synthase in antigen-stimulated RBL-2H3 cells. These anti-allergic activities of WB were mediated by the inactivation of extracellular signal-regulated kinase and p38 mitogen-activated protein kinase, which play important roles in degranulation and expression of various allergic and inflammatory molecules. In agreement with its in vitro effects, WB inhibited immunoglobulin E (IgE)/antigen-induced and compound 48/80-induced anaphylactic reactions in vivo. Taken together, these findings suggest the pharmacological potential of WB in the regulation of allergic diseases, including allergic rhinitis, atopic dermatitis, asthma and anaphylaxis.

In vitro anti-inflammatory effects of curcumin on mast cell-mediated allergic responses via inhibiting FcεRI protein expression and protein kinase C delta translocation.

Allergy is a hypersensitivity reaction when exposed to certain environmental substances. It shows high relation between immunoglobulin E (IgE) binding to a specific receptor (FcεRI), pro-inflammatory cytokines, and mediators with allergic inflammation responses. Curcumin is a yellow pigment isolated from the turmeric. Curcumin possesses antioxidant and anti-inflammatory properties as well as exhibits significant chemopreventive activity. This study was aimed to investigate the in vitro assessment of the regulation of curcumin on allergic inflammatory responses on rat basophil leukemia (RBL)-2H3 and human pre-basophils (KU812) cell lines. Curcumin showed the activity against histamine and β-hexosaminidase releases from both IgE-mediated and A23187-induced cells degranulation. The morphological observation also confirmed that curcumin inhibits cells degranulation. IgE-mediated allergic responses and significantly induced mast cells intracellular reactive oxygen species (ROS) production. Curcumin reduced ROS production from IgE-mediated or A23187-induced cells degranulation. Curcumin also successfully reduced FcεRI expressions and some pro-inflammatory cytokines, such as interleukin (IL)-4 and IL-13. Furthermore, curcumin inhibited protein kinase C (PKC)-δ translocation from cytosolic to particulate. These results suggested that curcumin can alleviate both the IgE-mediated and calcium ionosphere A23187-stimulated allergic responses through reducing the release of the allergic mediators.

Scrodentoid A Inhibits Mast Cell-Mediated Allergic Response by Blocking the Lyn-FcεRIβ Interaction.

Background: Mast cells are considered an attractive therapeutic target for treating allergic diseases, and the Lyn–FcεRIβ interaction is essential for mast cell activation. This study investigated the antiallergic effect of scrodentoid A (SA) on mast cells and mast cell–mediated anaphylaxis.Methods: For in vitro experiments, mast cells were treated with SA. Cell proliferation was tested using the XTT assay. The mRNA expression of various cytokines and chemokines was measured using qPCR. The levels of histamine, eicosanoids (PGD2, LTC4), and cytokines were measured using enzyme immunoassay kits. Signaling was investigated using Western blotting and immunoprecipitation. For in vivo experiments, the antiallergic activity of SA was evaluated using two mouse models of passive anaphylaxis as passive cutaneous and systemic anaphylaxis. The mechanism was investigated through immunohistochemistry and immunofluorescence.Results: SA considerably inhibited immunoglobulin (Ig) E-mediated mast cell activation, including β-hexosaminidase release, mRNA and protein expression of various cytokines, and PGD2 and LTC4 release. Oral administration of SA effectively and dose-dependently suppressed mast cell–mediated passive cutaneous and systemic anaphylaxis. SA significantly attenuated the activation of Lyn, Syk, LAT, PLCγ, JNK, Erk1/2, and Ca2+ mobilization without Fyn, Akt, and P38 activation by blocking the Lyn–FcεRIβ interaction.Conclusions: SA suppresses mast cell–mediated allergic response by blocking the Lyn–FcεRIβ interaction in vitro and in vivo. SA may be a promising therapeutic agent for allergic and other mast cell–related diseases.

Inhibitory effect of taxifolin on mast cell activation and mast cell-mediated allergic inflammatory response

The aim of the present study is to investigate the anti-inflammatory and anti-allergic effects of taxifolin on mast cells and mast cell-mediated allergic reaction. We assessed the effect of taxifolin on the activation of bone marrow-derived mast cells (BMMCs) and rat basophilic leukemia (RBL)-2H3 cells induced by immunoglobulin E (IgE)/antigen (Ag), and the activation of human mast cell line (HMC-1) induced by PMA plus A23187. Taxifolin inhibited degranulation, generation of leukotriene C4 (LTC4), production of interlukin-6 (IL-6), and expression of cyclooxygenase-2 (COX-2) through blocking intracellular Ca2+ mobilization, phosphorylation of phospholipase Cγ (PLCγ) and mitogen-activated protein kinases (MAPKs), translocation of cytosolic phospholipase A2 (cPLA2) and 5-lipoxygenase (5-LO), and Akt/IKK/NF-κB pathway, in BMMC cells. Furthermore, taxifolin suppressed phosphorylation of Syk, but without effect on Fyn and Lyn. Taxifolin also inhibited activation of RBL-2H3 and HMC-1 cells via Akt/IKK/NF-κB and MAPKs/cPLA2 signal pathway. Treatment with taxifolin attenuated the mast cell-mediated passive cutaneous anaphylaxis (PCA) reaction. Our results suggest that taxifolin might become a potential drug candidate for the treatment of allergic and inflammatory diseases.

Berberine suppresses mast cell-mediated allergic responses via regulating FcɛRI-mediated and MAPK signaling

The anti-allergic effect of berberine was evaluated in cellular and animal models of allergic responses. In this study, the results of the in vitro model of immunoglobulin (Ig) E-mediated mast cell degranulation showed that berberine significantly inhibited the release of β-hexosaminidase (β-HEX), histamine, IL-4 and TNF-α in rat basophilic leukemia cells (RBL-2H3 cells). Pretreatment with berberine prevented morphological changes in IgE-stimulated RBL-2H3 cells such as the recovery of an elongated shape. Pretreatment with berberine also suppressed the phosphorylation of antigen-induced Lyn, Syk, and Gab2, thus suppressing the downstream MAPK pathways. In the in vivo model of allergic responses, administration of berberine inhibited passive cutaneous anaphylaxis (PCA) in mice. The above results indicate berberine could suppress mast cell activation and allergic responses.

Anti-Inflammatory Effects of Cold Thermal Therapy on Allergic Skin Inflammation Induced by Trimellitic Anhydride in BALB/c Mice.

Cold and hot thermal therapies are widely used as a traditional therapy in many cultures and are often prescribed in the treatment of various musculoskeletal and neurological conditions which present themselves to primary care physicians. However, there are no reports that investigated either the effects of cold and hot thermal therapies on the skin inflammation of trimellitic anhydride- (TMA-) induced dermatitis-like contact hypersensitivity (CHS) mouse model, or the mechanism of thermal therapy on allergic skin inflammation. Therefore, in this study, to reveal the anti-inflammatory effect of thermal therapy and its mechanism on TMA-induced CHS, we analyzed ear-swelling response (ear edema), vascular permeability, serum IgE levels, histological examination, and histamine and Th2 cytokine levels. Cold thermal therapy reduced the ear-swelling response, the vascular permeability, the serum IgE levels, and the infiltration of eosinophils and mast cells as well as the mast cell degranulation. To determine the mechanism by which cold thermal therapy inhibits allergic skin inflammation, detailed studies were carried out revealing that cold thermal therapy suppressed IL-4 and IL-5 secretion and mast cell activation. These results indicated that cold thermal therapy cures skin inflammation of TMA-induced CHS by decreasing Th2 cytokine release, especially IL-4 and IL-5, and mast cell activation. These data suggest that new insight into the mechanism of robust therapeutic effects of cold thermal therapy against allergic dermatitis, and cold thermal therapy may prove to be a useful therapeutic modality on allergic inflammatory diseases as traditional use as well as Th2- or mast cell-mediated allergic responses.

Imperatorin Suppresses Anaphylactic Reaction and IgE-Mediated Allergic Responses by Inhibiting Multiple Steps of FceRI Signaling in Mast Cells: IMP Alleviates Allergic Responses in PCA.

This study is to investigate the effects of imperatorin (IMP) on allergic responses mediated by mast cells, both in vitro and in vivo. Passive cutaneous anaphylaxis (PCA) model was established. Histological detection was performed to assess the ear histology. ELISA and Western blot analysis were used to detect the levels of corresponding cytokines and signalling pathway proteins. IMP decreased the leakage of Evans blue and the ear thickness in the PCA models, in a dose-dependent manner, and alleviated the degranulation of mast cells. Moreover, IMP reduced the expression of TNF-α, IL-4, IL-1β, IL-8, and IL-13. Furthermore, IMP inhibited the phosphorylation levels of Syk, Lyn, PLC-γ1, and Gab2, as well as the downstream MAPK, PI3K/AKT, and NF-κB signaling pathways. In addition, IMP inhibited the mast cell-mediated allergic responses through the Nrf2/HO-1 pathway. IMP attenuates the allergic responses through inhibiting the degranulation and decreasing the expression levels of proinflammatory cytokines in the mast cells, involving the PI3K/Akt, MAPK, NF-κB, and Nrf2/HO-1 pathways.

Role of Zinc Signaling in the Regulation of Mast Cell-, Basophil-, and T Cell-Mediated Allergic Responses.

Zinc is essential for maintaining normal structure and physiological function of cells. Its deficiency causes growth retardation, immunodeficiency, and neuronal degeneration. Zinc homeostasis is tightly regulated by zinc transporters and metallothioneins that control zinc concentration and its distribution in individual cells and contributes to zinc signaling. The intracellular zinc signaling regulates immune reactions. Although many molecules involved in these processes have zinc-binding motifs, the molecular mechanisms and the role of zinc in immune responses have not been elucidated. We and others have demonstrated that zinc signaling plays diverse and specific roles in vivo and in vitro in studies using knockout mice lacking zinc transporter function and metallothionein function. In this review, we discuss the impact of zinc signaling focusing particularly on mast cell-, basophil-, and T cell-mediated inflammatory and allergic responses. We also describe zinc signaling dysregulation as a leading health problem in inflammatory disease and allergy.

Epigenetic Regulation via Altered Histone Acetylation Results in Suppression of Mast Cell Function and Mast Cell-Mediated Food Allergic Responses.

Mast cells are highly versatile cells that perform a variety of functions depending on the immune trigger, context of activation, and cytokine stimulus. Antigen-mediated mast cell responses are regulated by transcriptional processes that result in the induction of numerous genes contributing to mast cell function. Recently, we also showed that exposure to dietary agents with known epigenetic actions such as curcumin can suppress mast cell-mediated food allergy, suggesting that mast cell responses in vivo may be epigenetically regulated. To further assess the effects of epigenetic modifications on mast cell function, we examined the behavior of bone marrow-derived mast cells (BMMCs) in response to trichostatin A (TSA) treatment, a well-studied histone deacetylase inhibitor. IgE-mediated BMMC activation resulted in enhanced expression and secretion of IL-4, IL-6, TNF-α, and IL-13. In contrast, pretreatment with TSA resulted in altered cytokine secretion. This was accompanied by decreased expression of FcεRI and mast cell degranulation. Interestingly, exposure to non-IgE stimuli such as IL-33, was also affected by TSA treatment. Furthermore, continuous TSA exposure contributed to mast cell apoptosis and a decrease in survival. Further examination revealed an increase in I-κBα and a decrease in phospho-relA levels in TSA-treated BMMCs, suggesting that TSA alters transcriptional processes, resulting in enhancement of I-κBα transcription and decreased NF-κB activation. Lastly, treatment of wild-type mice with TSA in a model of ovalbumin-induced food allergy resulted in a significant attenuation in the development of food allergy symptoms including decreases in allergic diarrhea and mast cell activation. These data therefore suggest that the epigenetic regulation of mast cell activation during immune responses may occur via altered histone acetylation, and that exposure to dietary substances may induce epigenetic modifications that modulate mast cell function.

An Anti-Cancer Drug Candidate CYC116 Suppresses Type I Hypersensitive Immune Responses through the Inhibition of Fyn Kinase in Mast Cells.

Mast cells are the most prominent effector cells of Type 1 hypersensitivity immune responses. CYC116 [4-(2-amino-4-methyl-1,3-thiazol-5-yl)-N-[4-(morpholin-4-yl)phenyl] pyrimidin-2-amine] is under development to be used as an anti-cancer drug, but the inhibitory effects of CYC116 on the activation of mast cells and related allergy diseases have not reported as of yet. In this study, we demonstrated, for the first time, that CYC116 inhibited the degranulation of mast cells by antigen stimulation (IC50, ∼1.42 µM). CYC116 also inhibited the secretion of pro-inflammatory cytokines including TNF-α (IC50, ∼1.10 µM), and IL-6 (IC50, ∼1.24 µM). CYC116 inhibited the mast cell-mediated allergic responses, passive cutaneous anaphylaxis (ED50, ∼22.5 mg/kg), and passive systemic anaphylaxis in a dose-dependent manner in laboratory experiments performed on mice. Specifically, CYC116 inhibited the activity of Fyn in mast cells and inhibited the activation of Syk and Syk-dependent signaling proteins including LAT, PLCγ, Akt, and MAP kinases. Our results suggest that CYC116 could be used as an alternative therapeutic medication for mast cell-mediated allergic disorders, such as atopic dermatitis and allergic rhinitis.