Degranulation In RBL-2H3 Cells Research Articles

Sea cucumber chondroitin sulfate polysaccharides attenuate OVA-induced food allergy in BALB/c mice associated with gut microbiota metabolism and Treg cell differentiation.

Previous research studies have shown that sulfated polysaccharides can inhibit food allergy, but the detailed mechanism remains largely unknown. In this study, RBL-2H3 cells were used to compare the anti-allergic activities of four sulfated polysaccharides, and an ovalbumin (OVA)-sensitized allergic mouse experiment was used to explore their desensitization effect, with regard to the alteration in gut microbiota and immune cell differentiation. Compared with the shark, bovine and porcine chondroitin sulfate, sea cucumber chondroitin sulfate (SCCS) significantly inhibited the degranulation of RBL-2H3 cells. SCCS reduced allergic symptoms and protected the jejunum from injury in mice. Furthermore, SCCS increased the relative abundance of Lachnospiraceae NK4A136, decreased the relative proportion of Prevotellaceae NK3B31, and up-regulated the secretion of short chain fatty acids such as butyric acid in the feces, resulting in an increase in the mucin 2 (MUC2) secretion by goblet cells HT-29. Meanwhile, SCCS induced the differentiation of regulatory T cells in the mesenteric lymph nodes of mice. This study provides a deeper understanding of the functioning mechanism of SCCS in alleviating food allergy and may guide the development and production of anti-allergy active ingredients.

The Heterogeneity of Ovomucoid-Specific IgE Idiotype Is Associated With Egg Allergy Symptom Severity.

Immunoglobulin E (IgE)-mediated egg allergy presents as one of the most common food allergies. The level of specific IgE (sIgE) antibody is widely used as an important in vitro diagnostic indicator. However, sIgE antibody levels are often inconsistent with the clinical manifestations of patients. The heterogeneity of egg-specific IgE idiotypes (sIgE-IDs) may help reflect clinical egg allergy severity. Eight peptides were synthesized, corresponding to the linear epitopes of ovomucoid (OVM). The sIgE-IDs of egg-allergic patients were detected by enzyme-linked immunosorbent assay. Fresh peripheral blood was collected from patients with different heterogeneity strength of sIgE-ID, and egg extract was used as a stimulus to the basophil activation test (BAT). RBL-2H3 cells were sensitized with serum with different strength of sIgE-ID heterogeneity and the release rate of β-hexosaminidase was calculated. Among 75 patients with egg allergy, 24% had sIgE for all epitopes and 85% had sIgE for at least one epitope. Analysis of individual patients revealed differences in epitope recognition patterns among the patients, that is, heterogeneity in sIgE-ID. More importantly, the number of IgE-positive peptides had a strong correlation with allergic symptoms in egg-allergic patients (r = 0.706). BAT and RBL-2H3 cell degranulation confirmed that higher sIgE-ID heterogeneity strength was more effective in inducing effector cell responses. Our results suggest that the greater the heterogeneity strength of OVM-sIgE-ID, the more severe the allergic symptoms.

Protection of Allergic Asthma in Mice by Black Rice Bran Bioprocessed with Shiitake Mushroom Mycelia

We evaluated the potential of orally fed new food formulations to inhibit biomarkers reported to be involved in the causes of allergic asthma in mice. Asthma, a serious non-communicable disease, affects both adults and children and can be undertreated. New functional foods could provide therapeutic approaches. Here, the anti-asthma mechanism of a new functional food and three isolated fractions produced by bioprocessing black rice bran with shiitake mushroom mycelia was evaluated in mast cells, B cells, and orally fed mice and compared with non-bioprocessed black rice bran. In vitro, the treatments inhibited RBL-2H3 cell degranulation and immunoglobulin E (IgE) production. The in vitro anti-asthma effects were confirmed in orally fed mice following asthma induction by alumina and chicken egg ovalbumin (OVA). The suppression of asthma resulted from the inhibition of inflammation- and immune-related substances, including OVA-specific IgE, thymic stromal lymphopoietin, eotaxin, leukotriene C4, prostaglandin D2, and vascular cell adhesion molecule-1 in bronchoalveolar lavage fluid and serum. The treatment also reversed the thickening of the lung airway wall. The inflammation and asthma inhibition seems to be regulated by the balance of the T-helper cells’ Th1/Th2 immune response and the inhibition of multiple biomarkers associated with the cause of asthma. Future human clinical studies with adults and children should determine the potential therapeutic value of the anti-asthma effects of the new functional foods.

Aqueous Extract from Cuminum cyminum L. Seed Alleviates Ovalbumin-Induced Allergic Rhinitis in Mouse via Balancing of Helper T Cells

Cuminum cyminum L. (cumin) seeds are widely used as a spice. Although we previously reported that the aqueous extract of cumin seeds suppresses the degranulation of rat basophilic RBL-2H3 cells, it has not been clarified whether the extract alleviates actual allergy symptoms in vivo. Therefore, in this study, we investigated the effect of oral administration of cumin seed aqueous extract (CAE) in ovalbumin (OVA)-induced allergic rhinitis. BALB/c mice were randomly divided into the following three groups: control group (five mice), OVA group (five mice), and OVA + CAE group (five mice). Allergic rhinitis was induced by sensitization (intraperitoneal, 25 μg OVA and 1.98 mg aluminum hydroxide gel) followed by challenge (intranasal, 400 μg OVA). The oral administration of CAE (25 mg/kg) reduced the sneezing frequency of OVA-induced allergic rhinitis model mice. In addition to reducing the serum immunoglobulin E and IL-4 levels, the oral administration of CAE reduced the production of T-helper type-2 (Th2) cytokines (IL-4, IL-5, IL-10, and IL-13) in the splenocytes of the model mice. Furthermore, a significant increase in the ratio of Th1 to Th2 cells was observed in the CAE-administered group. Our findings suggest that the ingestion of CAE improves T cell balance, the dominant state of Th2, and alleviates allergic rhinitis symptoms.

The amino acids differences in epitopes may promote the different allergenicity of ovomucoid derived from hen eggs and quail eggs

Quail egg ovomucoid can inhibit activation of basophils and eosinophils, while hen egg ovomucoid has been shown to be a major allergen, named Gal d 1. At present, the differences in structure and function between two ovomucoid are unclear. We found the homology of ovomucoid in quail eggs and hen eggs reached 77 %. Compared with hen egg ovomucoid, the distribution of secondary structure was different in AA52−53, AA57−58, AA66−68, AA71−72, AA131−133, AA139−140, AA157−159 and AA184−185. Among 9 epitopes of egg ovomucoid, there were different amino acids from quail egg ovomucoid in 8 epitopes. Recombination quail egg ovomucoid had trypsin inhibition activity and quail egg ovomucoid didn’t specifically bind to serum of eggs allergic patients. Quail egg ovomucoid can significantly inhibit RBL-2H3 cells degranulation and protect cells morphology to a certain extent, indicating quail egg ovomucoid can inhibit cells activation and have potential anti-allergic effects, which is related to trypsin inhibitory activity. The difference in sensitization compare to hen egg ovomucoid may be due to amino acids differences affecting protein structure by changing antigenic epitopes.

GRK2 inhibitors, paroxetine and CCG258747, attenuate IgE-mediated anaphylaxis but activate mast cells via MRGPRX2 and MRGPRB2.

G protein-coupled receptor (GPCR) kinase 2 (GRK2), which phosphorylates agonist-occupied GPCRs to promote their desensitization, has been investigated as an attractive therapeutic target for cardiovascular and metabolic diseases. Several GRK2-targeted inhibition strategies have been reported including the use of direct pharmacological inhibitors such as paroxetine (a widely prescribed antidepressant) and its analogs such as compound CCG258747. Cross-linking of high affinity IgE receptor (FcϵRI) on mast cells (MCs) and the resulting degranulation causes anaphylaxis and allergic asthma. Using gene silencing strategy, we recently showed that GRK2 contributes to FcεRI signaling and MC degranulation. The purpose of this study was to determine if the GRK2 inhibitors paroxetine and CCG258747 modulate FcεRI-mediated MC responses in vitro and in vivo. Utilizing rat basophilic leukemia (RBL-2H3) cells and primary mouse lung MCs (LMCs), we found that paroxetine and CCG258747 inhibit FcϵRI-mediated calcium mobilization and degranulation. Furthermore, intravenous administration of paroxetine and CCG258747 in mice resulted in substantial reduction of IgE-mediated passive cutaneous anaphylaxis. Unlike LMCs, human cutaneous MCs abundantly express a novel GPCR known as MRGPRX2 (mouse; MRGPRB2). We found that in contrast to their inhibitory effects on FcεRI-mediated MC responses, both paroxetine and CCG258747 induce calcium mobilization and degranulation in RBL-2H3 cells stably expressing MRGPRX2 but not in untransfected cells. Furthermore, paroxetine and CCG258747 induced degranulation in peritoneal MCs from Wild-type (WT) mice in vitro and caused increased cutaneous vascular permeability in vivo, but these responses were substantially reduced in Mrgprb2−/− mice. Additionally, upon intradermal injection, paroxetine also induced neutrophil recruitment in WT but not Mrgprb2−/− mice. These findings suggest that in addition to their potential therapeutic utility against cardiovascular and metabolic disorders, paroxetine-based GRK2-inhibitors may serve to modulate IgE-mediated anaphylaxis and to enhance cutaneous host defense by harnessing MC’s immunomodulatory property through the activation of MRGPRX2/MRGPRB2.

Inhibition of MRGPRX2 but not FcεRI or MrgprB2-mediated mast cell degranulation by a small molecule inverse receptor agonist.

Mas-related G protein-coupled receptor-X2 (MRGPRX2) expressed on mast cells (MCs) contributes to hypersensitivity reactions to cationic US-Food and Drug Administration (FDA) approved drugs such as the neuromuscular blocking agent, rocuronium. In addition, activation of MRGPRX2 by the neuropeptide substance P (SP) and the pro-adrenomedullin peptide (PAMP-12) is associated with a variety of cutaneous conditions such as neurogenic inflammation, pain, atopic dermatitis, urticaria, and itch. Thus, small molecules aimed at blocking MRGPRX2 constitute potential options for modulating IgE-independent MC-mediated disorders. Two inverse MRGPRX2 agonists, named C9 and C9-6, have recently been identified, which inhibit basal G protein activation and agonist-induced calcium mobilization in transfected HEK293 cells. Substance P serves as a balanced agonist for MRGPRX2 whereby it activates both G protein-mediated degranulation and β-arrestin-mediated receptor internalization. The purpose of this study was to determine if C9 blocks MRGPRX2’s G protein and β-arrestin-mediated signaling and to determine its specificity. We found that C9, but not its inactive analog C7, inhibited degranulation in RBL-2H3 cells stably expressing MRGPRX2 in response to SP, PAMP-12 and rocuronium with an IC50 value of ~300 nM. C9 also inhibited degranulation as measured by cell surface expression of CD63, CD107a and β-hexosaminidase release in LAD2 cells and human skin-derived MCs in response to SP but not the anaphylatoxin, C3a or FcϵRI-aggregation. Furthermore, C9 inhibited β-arrestin recruitment and MRGPRX2 internalization in response to SP and PAMP-12. We found that a G protein-coupling defective missense MRGPRX2 variant (V282M) displays constitutive activity for β-arrestin recruitment, and that this response was significantly inhibited by C9. Rocuronium, SP and PAMP-12 caused degranulation in mouse peritoneal MCs and these responses were abolished in the absence of MrgprB2 or cells treated with pertussis toxin but C9 had no effect. These findings suggest that C9 could provide an important framework for developing novel therapeutic approaches for the treatment of IgE-independent MC-mediated drug hypersensitivity and cutaneous disorders.

Identification of components in coriander (Coriandrum sativum L.) inhibiting degranulation of RBL-2H3 cells

We found that a water-soluble extract of coriander (Coriandrum sativum L.) (leaves, petioles and stems) inhibits antigen-induced degranulation of RBL-2H3 cells, a rat basophil leukemia cell line. The aim of this study was to elucidate the anti-degranulation active components in the extract. The methanol-eluate fraction obtained by fractionation of the water-soluble extract using MCI gel column chromatography had strong activity, and eight components were isolated and identified. Two of them were identified as new compounds, (3S)-3-methyl-6-hydroxyisocoumarin 8-O-β-D-glucopyranoside (compound 1) and (7S,8R)-7,8-dihydro-8-β-D-glucopyranosyloxy-4-methoxy-7-methyl-5H-fro[2,3-g][2]benzopyran-5-one (compound 2). As a result of evaluation of anti-degranulation activity of eight components, seven of them, such as tryptophan, phenylalanine, dihydroxycoumarin glucoside, quercetin glycoside, rutin, compound 1, and compound 2, had the activity. These results indicated that the water-soluble extract of coriander contains several anti-degranulation substances.

Exploring the mechanism of sweetener neohesperidin dihydrochalcone on oral tolerance via a network pharmacology approach combined with vivo and vitro methods

Neohesperidin dihydrochalcone (NHDC) is a kind of sweetener widely used in food processing. Some artificial sweeteners induce food allergy by breaking oral tolerance (OT). The relationship between NHDC and oral tolerance are important in food safety. We explored the possible effects of NHDC on OT via network pharmacology combined with vivo and vitro experiments. NHDC was predicted to have effects on OT. It was focus on immunoglobulin production, inflammation and immunity. Then, OT mouse model and mast cell degranulation were applied to further explore the mechanism. NHDC could affect the Th2 response by suppressing the sIgG1 level in the serum and GATA-3 expression in the colon. NHDC could inhibit RBL-2H3 cells degranulation by suppressing the Ca2+ influx and MAPK signaling pathways. Results showed that NHDC can be safely applied in food processing and had promotional effects on oral tolerance.

Anti-Allergic Effect of Aqueous Extract of Coriander (Coriandrum sativum L.) Leaf in RBL-2H3 Cells and Cedar Pollinosis Model Mice

Coriander (Coriandrum sativum L.) is classified in the Apiaceae family and used as an herb. Coriander leaf has been reported to possess various health functions. Here, we report the anti-allergic effect of aqueous coriander leaf extract (ACLE). ACLE with 1.0 mg/mL or higher concentration significantly inhibited degranulation of RBL-2H3 cells in a concentration-dependent manner with no cytotoxicity. ACLE suppressed the increase in the intracellular Ca2+ concentration in response to antigen-specific stimulation. Immunoblot analysis demonstrated that ACLE significantly downregulates phosphorylation of phosphatidylinositol 3-kinase and tends to downregulate phosphorylation of Syk kinase in the signaling pathways activated by antigen-mediated stimulation. Oral administration of ACLE did not alter the sneezing frequency of pollinosis model mice stimulated with cedar pollen, but significantly reduced the serum IgE level. Our data show anti-allergic effects of coriander leaf in both cultured cells and pollinosis mice. These results suggest that coriander leaf has the potential to be a functional foodstuff with anti-allergy effects.

Melittin-derived peptides exhibit variations in cytotoxicity and antioxidant, anti-inflammatory and allergenic activities

ABSTRACT Melittin is a major component of bee venom; it is widely used in traditional medicine because of its therapeutic effects, such as anti-inflammatory effects. However, melittin has limited medical applications owing to its adverse effects, such as high cytotoxicity. In this study, we investigated the physiological activities of various hydrolyzed melittin-derived peptides to eliminate the cytotoxicity of melittin and enhance its efficacy. The 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay confirmed that melittin-derived peptides showed antioxidant activity comparable to that of melittin. Moreover, unlike melittin, which showed high cytotoxicity in the 3-(4,5-dimethylthiazol-2-yl)−5-(3-carboxymethoxyphenyl)−2-(4-sulfophenyl)−2H-tetrazolium inner salt (MTS) assay, the melittin-derived peptides showed negligible cytotoxicity. Among the melittin-derived peptides, the peptide composed of sequence TTGLPALISWIKRKRQQ (P1) showed inhibitory effects on the mRNA expression of inflammatory cytokines and phosphorylation of IκBα, similar to the effects of melittin in RAW 264.7 cells. Degranulation of RBL-2H3 cells was analyzed using a β-hexosaminidase release assay to confirm the allergenic activity of melittin and P1, which showed remarkably reduced allergenicity of P1 compared to that of melittin. These results indicate that P1 maintained the anti-inflammatory effects of melittin while reducing its cytotoxicity and allergic reactions. In conclusion, the melittin-derived peptide P1 efficiently decreased the adverse effects while maintaining the beneficial effects of melittin, making it suitable for therapeutic applications.

Umbelliferose Isolated from Cuminum cyminum L. Seeds Inhibits Antigen-Induced Degranulation in Rat Basophilic Leukemia RBL-2H3 Cells

Cuminum cyminum L. (cumin) is an annual plant of the Umbelliferae family native to Egypt. We previously showed that the aqueous extract of cumin seeds suppresses degranulation by downregulating the activation of antigen-induced intracellular signaling molecules in rat basophilic leukemia RBL-2H3 cells. However, the active substances in the extract have not yet been identified. Accordingly, herein, we aimed to ascertain the water-soluble substances present in cumin seeds that inhibit degranulation, which led to the identification of umbelliferose, a characteristic trisaccharide present in plants of the Umbelliferae family. Our study is the first to reveal the degranulation-suppressing activity of umbelliferose, and quantification studies suggest that cumin seed powder contains 1.6% umbelliferose. Raffinose, an isomer of umbelliferose, was also found to significantly suppress antigen-induced degranulation, but less so than umbelliferose. Both umbelliferose and raffinose contain sucrose subunits in their structures, with galactose moieties bound at different sites. These differences in structure suggest that the binding of galactose to the sucrose subunit at the α1-2 bond contributes to its strong degranulation-inhibiting properties.

Roots of Lithospermum erythrorhizon Alleviated Ovalbumin-Induced Allergic Rhinitis and IgE-triggered Degranulation of RBL-2H3 Cells

Lithospermum erythrorhizon (L. erythrorhizon) root is used in traditional medicine for its anti-inflammatory, antibacterial, and antioxidant properties. However, no studies have examined its impact on allergic rhinitis (AR). Here, we explored the protective effects of L. erythrorhizon in immunoglobulin E (IgE)-stimulated RBL-2H3 cells and in an ovalbumin (OVA)-induced AR mouse model. In the latter, we examined nasal mucosal inflammation, allergen-specific cytokine production, and histological changes to the nasal mucosa. In the mouse model, oral administration of an ethanol extract of L. erythrorhizon (LE) led to a marked reduction in rubbing and sneeze frequency, a significant decrease in serum OVA-specific IgE and IgG1 levels, and a significant increase in the IgG2a/IgG1 ratio. LE also reduced expression of interleukin (IL)-4, IL-5, and IL-13 in nasal lavage fluid (NALF), and suppressed inflammatory cell infiltration and epithelial degradation in nasal tissues. In IgE-stimulated RBL-2H3 cells, LE suppressed release of degranulation markers such as β-hexosaminidase and histamine. Based on these findings, we suggest that LE may ameliorate OVA-induced AR by regulating mast cell-mediated inflammatory responses.

Inhibition of TRPV2 Channel Activation by NK-4, a Cryptocyanine Dye

Transient receptor potential vanilloid 2 (TRPV2) channels are expressed and play functional roles in various immune cells. Physical stimuli leading to TRPV2 activation causes mast cell degranulation. Besides their roles in immune cells, it has been shown that TRPV2 channels are pathophysiologically relevant to degenerative muscular diseases such as dilated cardiomyopathy and muscular dystrophy. Hence, development of drug candidates that inhibit human TRPV2 activation is an urgent matter. NK-4, a cryptocyanine dye, inhibited agonist-induced TRPV2 activity in mouse TRPV2-transfected HEK293 cells. However, it remains unclear whether NK-4 exerts regulatory effects on the activation of human TRPV2 channels. In this study, we show that NK-4 inhibits intracellular Ca2+ increase in human TRPV2-transfected HEK293 cells preactivated with a TRPV2 agonist. The inhibitory effect of NK-4 (IC50=0.27 μM) on human TRPV2 activation was 74-fold stronger than that on mouse TRPV2 activation (IC50=20 μM). NK-4 also inhibited the agonist-induced TRPV2 expression at the plasma membrane, when the human TRPV2-expressing cells were stimulated with the agonist in the presence of NK-4. These results suggest that NK-4 abrogates the agonist-induced signaling events leading to human TRPV2 activation. Furthermore, TRPV2 agonist caused degranulation of RBL-2H3 cells, which represents a phenomenon related to physical urticarias. NK-4 suppressed the release of β-hexosaminidases upon degradation with IC50 of 1.9 μM, 35-fold lower than that determined with an anti-allergic drug, Epinastine. Our results suggest that NK-4 would be a potential therapeutic strategy to resolve dilated cardiomyopathy and its associated heart failure as well as physical urticarias.

Evaluation of the structure-activity relationship between allergenicity and spatial conformation of ovalbumin treated by pulsed electric field

The aim of the present study was to investigate the effect of pulsed electric field (PEF) treatment on ovalbumin (OVA) induced allergens and reveal potential allergy regulatory mechanisms. At 10 kV/cm, OVA-induced allergic symptoms were significantly reduced, and the capacity of OVA to bind with specific IgG1 and IgE was reduced by 10.32% and 3.61%, respectively. Furthermore, the degranulation of RBL-2H3 cells and allergen activity were also reduced by 4.63% and 22.15%, respectively. Interestingly, the α-helix content was reduced by 5.81% and the fluorescence intensity was increased by 6.90% with PEF treatment. At 10 kV/cm, water contact angle and surface hydrophobicity increased by 8.40% and 0.18%, respectively, indicating that PEF treatment increased the exposure of hydrophobic amino acid residues. PEF treatment alters the hydrogen bonding and hydrophobic interactions in the protein, which masks the binding sites of sensitized epitopes, and consequently reduces allergies.

LC-MS/MS metabolomics-facilitated identification of the active compounds responsible for anti-allergic activity of the ethanol extract of Xenostegia tridentata.

In vivo and in vitro anti-allergic activities of ethanol extract of Xenostegia tridentata (L.) D.F. Austin & Staples were investigated using passive cutaneous anaphylaxis reaction assay and RBL-2H3 cell degranulation assay, respectively. The crude ethanol extract exhibited promising activities when compared with the known anti-allergic agents, namely dexamethasone and ketotifen fumarate. The ethyl acetate subfraction showed the highest anti-allergic activity among various sub-partitions and showed better activity than the crude extract, consistent with the high abundance of total phenolic and flavonoid contents in this subfraction. LC-MS/MS metabolomics analysis and bioassay-guided isolation were then used to identify chemical constituents responsible for the anti-allergic activity. The results showed that major components of the ethyl acetate subfraction consist of 3,5-dicaffeoylquinic acid, quercetin-3-O-rhamnoside, kaempferol-3-O-rhamnoside and luteolin-7-O-glucoside. The inhibitory activity of the isolated compounds against mast cell degranulation was validated, ensuring their important roles in the anti-allergic activity of the plant. Notably, besides showing the anti-allergic activity of X. tridentata, this work highlights the role of metabolomic analysis in identifying and selectively isolating active metabolites from plants.

A novel strategy for the discovery and validation of allergic component and its action mechanism in Red Ginseng

Red ginseng (a processed product of ginseng) is a famous herbal medicine or healthcare product widely used in Asia. However, there are many reports about anaphylactoid reaction of red ginseng. This study aims to establish a novel strategy for discovering and validating allergic component and its action mechanism in red ginseng. Firstly, RBL-2H3 cell degranulation experiment was performed by real-time cell analysis (RTCA) system and β-hexosaminase release test to illustrate the anaphylactoid reaction induced by red ginseng. Then, combined with ultra-performance liquid chromatography quadrupole/time of flight mass spectrometry (UPLC-Q/TOF-MS) analysis, the main components of red ginseng for inducing degranulation of RBL-2H3 cells was explored. Furthermore, the compounds with the parent nucleus structure of allergic component were studied to figure out whether they could induce RBL-2H3 cell degranulation, and the relationship between the structures of compounds and degranulation was further investigated. Finally, the underlying mechanism of allergic components was explored based on network toxicology and molecular docking method, which was further verified by western blotting analysis. Our findings demonstrated that red ginseng extract could induce degranulation of RBL-2H3 cells, and ginsenoside Ro (an oleanane-type triterpene saponin), was confirmed to be the main allergic component. Meanwhile, both ginsenoside Ro (Ro) and other oleanane-type triterpene saponins could induce degranulation of RBL-2H3 cells, and the compound with disaccharide chain on C3 position had the strongest activity of degranulation. And their mechanism of inducing degranulation of RBL-2H3 cells involved in PI3K-Akt pathway. The results would provide a reference for the quality control and evaluation of safety of herb medicines or healthcare products containing oleanane-type triterpenoid saponins. Our method offers a novel strategy for screening allergic components in red ginseng and promoting further study of safety evaluation of red ginseng.

Tanshinone IIA improves degranulation of mast cells and allergic rhinitis induced by ovalbumin by inhibiting the PLCγ1/PKC/IP3R pathway.

Allergic rhinitis (AR) is a common allergic inflammatory and chronic reactive disease caused by allergen-induced immunoglobulin E (IgE). Tanshinone IIA (Tan IIA) is one of the active ingredients in Salvia miltiorrhiza Bunge (Danshen) and plays a vital role in inhibiting inflammation. Thus, we hypothesized that Tan IIA has anti-allergic effects and studied the function of Tan IIA in mast cells and an AR animal model. We induced RBL-2H3 cell sensitization with monoclonal anti-2,4,6-dinitrophenyl-immunoglobulin (Ig) E/human serum albumin (DNP-IgE/HSA) and constructed an ovalbumin (OVA)-induced AR model in mice. The role of Tan IIA in AR progression was studied using the MTT assay, ELISA, western blot, toluidine blue staining, HE staining, and Alcian blue and safranin O (A&S) staining. Tan IIA treatment significantly increased IgE/HSA-induced cell viability. However, Tan IIA treatment markedly downregulated the expression levels of β-hexosaminidase, histamine, tumor necrosis factor (TNF-α), interleukin 1β (IL-1β), IL-4, and IL-5 in IgE/HSA-induced cells. Furthermore, Tan IIA improved typical symptoms in the OVA-induced AR model mice by inhibiting the phospholipase Cγ1 (PLCγ1)/protein kinase C (PKC)/IP3R pathway. Additionally, Tan IIA effectively improved the degranulation of RBL-2H3 cells and OVA-induced AR in mice. Together, these results suggest that Tan IIA may be a potential drug for the treatment of AR in the future.

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.

Sphingoid base in pineapple glucosylceramide suppresses experimental allergy by binding leukocyte mono-immunoglobulin-like receptor 3.

BACKGROUNDThe increase in patients suffering from type I hypersensitivity, including hay fever and food allergy, is a serious public health issue around the world. Recent studies have focused on allergy prevention by food factors with fewer side effects. The purpose of this study was to evaluate the effect of dietary glucosylceramide from pineapples (P‐GlcCer) on type I hypersensitivity and elucidate mechanisms.RESULTSOral administration of P‐GlcCer inhibited ear edema in passive cutaneous anaphylaxis reaction. In a Caco‐2/RBL‐2H3 co‐culture system, P‐GlcCer inhibited β‐hexosaminidase release from RBL‐2H3 cells. The direct treatment of P‐GlcCer on RBL‐2H3 did not affect β‐hexosaminidase release, but sphingoid base moiety of P‐GlcCer did. These results predicted that sphingoid base, a metabolite of P‐GlcCer, through the intestine inhibited type I hypersensitivity by inhibiting mast cell degranulation. In addition, the inhibitory effects of P‐GlcCer on ear edema and degranulation of RBL‐2H3 cells were canceled by pretreatment of leukocyte mono‐immunoglobulin‐like receptor 3 (LMIR3)‐Fc, which can block LMIR3‐mediated inhibitory signals.CONCLUSIONIt was demonstrated that a sphingoid base, one of the metabolites of P‐GlcCer, may inhibit mast cell degranulation by binding to LMIR3. The oral administration of P‐GlcCer is a novel and attractive food factor that acts directly on mast cells to suppress allergy. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.