Genetically encoded sensors for measuring histamine release both in vitro and in vivo.

Histamine (HA) is a key biogenic monoamine involved in a wide range of physiological and pathological processes in both the central and peripheral nervous systems. Because the ability to directly measure extracellular HA in real time will provide important insights into the functional role of HA in complex circuits under a variety of conditions, we developed a series of genetically encoded G-protein-coupled receptor-activation-based (GRAB) HA (GRABHA) sensors with good photostability, sub-second kinetics, nanomolar affinity, and high specificity. Using these GRABHA sensors, we measured electrical-stimulation-evoked HA release in acute brain slices with high spatiotemporal resolution. Moreover, we recorded HA release in the preoptic area of the hypothalamus and prefrontal cortex during the sleep-wake cycle in freely moving mice, finding distinct patterns of HA dynamics between these specific brain regions. Thus, GRABHA sensors are robust tools for measuring extracellular HA transmission in both physiological and pathological processes.

Modulation of the Immune Response to Allergies Using Alternative Functional Foods.

Modulation of the allergic immune response through alternative therapies is a field of study that aims to address allergic reactions differently from traditional approaches. These therapies encompass the utilization of natural functional foods, which have been observed to exert an influence on the immune response, thus mitigating the severity of allergies. Indeed, some studies suggest that the incorporation of these nutraceuticals can regulate immune function, leading to a reduction in histamine release and subsequent alleviation of allergic symptoms. Moreover, certain herbs and dietary supplements, such as curcumin, are believed to possess anti-inflammatory properties, which may serve to moderate allergic responses. Although the results remain somewhat mixed and require further research, these alternative therapies exhibit the potential to impact the allergic immune response, thereby providing complementary options to conventional treatments. Therefore, in this review, we aim to provide an updated account of functional foods capable of modulating the immune response to allergies. In that sense, the review delves into functional foods sourced from plants (phytochemicals), animals, and marine algae. Emphasis is placed on their potential application in the treatment of allergic disorders. It also provides an overview of how these foods can be effectively utilized as functional foods. Additionally, it explores the molecular mechanisms and scientific validity of various bioactive natural compounds in the management of allergies.

Mrgprb2 gene plays a role in the anaphylactoid reactions induced by Houttuynia cordata injection.

ETHNOPHARMACOLOGICAL RELEVANCE: Houttuynia cordata Thunb., a plant belonging to the family of Saururaceae, has been used as a traditional Chinese medicine for more than 1500 years. Because of its various pharmacological activities, it was widely used as antipyretic, detoxification, anti-inflammatory drugs. Houttuynia cordata (HC) injection was prepared using contemporary methods to extract effective components from H. cordata Thunb. However, the adverse event reports of HC injection are accumulating remarkably with the HC injection clinical applications increased. Previous studies demonstrated that the major side effects of HC injection were anaphylactoid reactions. Our work might shed the light on the role of Mas-related G-protein coupled receptor-X2 (MRGPRX2) in modulating drug-induced anaphylactoid reactions. AIM OF THE STUDY: We aimed to investigate the role of the mouse Mas-related G-protein coupled receptor B2 (Mrgprb2) (the orthologous gene of human MRGPRX2) in anaphylactoid reactions induced by HC injection. MATERIALS AND METHODS: Mrgprb2 related anaphylactoid reactions induced by HC injection were investigated by histamine/ß-hexosaminidase releasing, mast cell degranulation, and hind paw swelling assays by using a Mrgprb2 knockout mouse model. Furthermore, the transcriptomic profiles of the anaphylactoid reaction induced by HC injection was analyzed by RNA sequencing. RESULTS: Mice without Mrgprb2 exhibited significantly decreasing in mast cell degranulation, serum histamine release, and hind paw swelling degrees. The RNA sequencing results indicated that Mrgprb2 could play a pivotal role in HC injection induced anaphylactoid reaction mediated by mTOR/AMPK pathway. Intriguingly, our results showed that Mrgprb2 might involve in Compound 48/80 induced anaphylactoid reactions mediated by Reelin/E-cadherin axis, which suggested different roles of Mrgprb2 in anaphylactoid reactions induced by HC injection and C48/80. CONCLUSION: Our studies reported effects and underlying mechanisms of Mrgprb2 in the anaphylactoid reaction induced by HC injection.

The effect of local passive heating on skeletal muscle histamine concentration: implications for exercise-induced histamine release.

Aerobic exercise induces mast cell degranulation and increases histamine formation by histidine decarboxylase, resulting in an ∼150% increase in intramuscular histamine. The purpose of this study was to determine if the increase in skeletal muscle temperature associated with exercise is sufficient to explain this histamine response. Specifically, we hypothesized that local passive heating that mimics the magnitude and time course of changes in skeletal muscle temperature observed during exercise would result in increased intramuscular histamine concentrations comparable to exercising values. Seven subjects participated in the main study in which pulsed short-wave diathermy was used to passively raise the temperature of the vastus lateralis over 60 min. Heating increased intramuscular temperature from 32.6°C [95% confidence interval (CI) 32.0°C to 33.2°C] to 38.9°C (38.7°C to 39.2°C) (P < 0.05) and increased intramuscular histamine concentration from 2.14 ng/mL (1.92 to 2.36 ng/mL) to 2.97 ng/mL (2.57 to 3.36 ng/mL) (P < 0.05), an increase of 41%. In a follow-up in vitro experiment using human-derived cultured mast cells, heating to comparable temperatures did not activate mast cell degranulation. Therefore, it appears that exercise-associated changes in skeletal muscle temperature are sufficient to generate elevations in intramuscular histamine concentration. However, this thermal effect is most likely due to changes in de novo histamine formation via histidine decarboxylase and not due to degranulation of mast cells. In conclusion, physiologically relevant increases in skeletal muscle temperature explain part, but not all, of the histamine response to aerobic exercise. This thermal effect may be important in generating positive adaptations to exercise training.NEW & NOTEWORTHY The "exercise signal" that triggers histamine release within active skeletal muscle during aerobic exercise is unknown. By mimicking the magnitude and time course of increasing skeletal muscle temperature observed during aerobic exercise, we demonstrate that part of the exercise-induced rise in histamine is explained by a thermal effect, with in vitro experiments suggesting this is most likely via de novo histamine formation. This thermal effect may be important in generating positive adaptations to exercise training.

Inhibitory effects of cyanidin-3-O-glucoside in black soybean hull extract on RBL-2H3 cells degranulation and passive cutaneous anaphylaxis reaction in mice.

Black soybean hull extract (BSHE) exhibits a variety of biological activities. However, little is known about the effects of BSHE on immunoglobulin E (IgE)-mediated type I allergic reactions. The anti-allergic effect of BSHE was assessed with the degranulation assay using rat basophilic leukemia RBL-2H3 cells and the passive cutaneous anaphylaxis (PCA) reaction in mice. An active compound in BSHE was identified by ultra-performance liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry analysis. BSHE inhibited the release of ß-hexosaminidase and histamine in RBL-2H3 cells, and cyanidin-3-O-glucoside (C3G) was identified as one of its active compounds. Oral administering of 200 µmol/kg of C3G to IgE-sensitized mice prior to antigen injection suppressed the PCA reaction, as compared with control (p < 0.01). Intravenous administration of BSHE (C3G content, 5.4%) more strongly inhibited PCA responses at lower doses (100 mg/kg, p < 0.01) than oral administration (1,000 mg/kg, p = 0.059). Intravenous C3G also suppressed PCA response at a low dose (40 mg/kg, p < 0.05), showing the same trend as BSHE. This information can be useful to design appropriate formulations of anthocyanin-based drug products to suppress allergic reactions. This study provides evidence for the potential use of BSHE and C3G for the prevention or the treatment of type I allergies.

Tripterine: A Potential Anti-Allergic Compound.

BACKGROUND: Tripterine (TRI), an active monomer in Tripterygium wilfordii, has significant pharmacological activities, such as anti-inflammatory, immunosuppressive and anti-tumor activities. TRI may be used to treat allergic diseases because of its characteristics of immunosuppression. OBJECTIVE: This study aims to explore the anti-allergic effect of TRI. METHODS: It was tested in vivo and in vitro in this study. RESULTS: The results showed that TRI could significantly inhibit histamine release from rat peritoneal mast cells; the inhibitory effect of TRI on histamine release was stronger than that of other known histamine inhibitors such as disodium cromoglyceride. TRI also significantly inhibited systemic anaphylactic shock induced by compound 48/80 and skin allergy induced by IgE, and inhibited the expression of inflammatory factors secreted by Human Mast Cells (HMC-1) induced by Phorbol 12-Myristate 13- Acetate (PMA) and calcium carrier A23187. In the animal model of allergic rhinitis induced by Ovalbumin (OA), the scores of friction, histamine, IgE, inflammatory factors and inflammatory cells decreased after TRI was administered orally or nasally. CONCLUSION: TRI, as an active immunoregulatory factor, has great potential in the treatment of mast cell-mediated allergic diseases.

Sophoricoside from Sophora japonica ameliorates allergic asthma by preventing mast cell activation and CD4+ T cell differentiation in ovalbumin-induced mice.

Asthma is a chronic inflammatory lung disorder with continuously increasing prevalence worldwide. Novel strategies are needed to prevent or improve asthma. The aim of this study was to investigate the effects of sophoricoside from Sophora japonica on allergic asthma. The mature seeds of S. japonica contain a large amount of sophoricoside. Sophoricoside reduced allergic and asthmatic symptoms by suppressing airway inflammation and antibody-antigen reaction in mouse models. In particular, sophoricoside suppressed immune cell recruitment into the airway lumens of the lungs and production of pro-inflammatory cytokines in the bronchoalveolar lavage fluid (BALF) of ovalbumin (OVA)-induced mice. It also decreased the amounts of histamine and arachidonic acid metabolites released in OVA-induced mice and antibody-antigen stimulated mast cells. In addition, sophoricoside decreased differentiation of naïve CD4+ T cells into T helper type 1 (Th1), Th2, and Th17 cells. Overall, we demonstrated that sophoricoside improved allergic asthma by suppressing mast cell activation and CD4+ T cell differentiation.

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

BACKGROUND: Oleanolic 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. PURPOSE: Given 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. METHODS: We 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. RESULTS: OA 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. CONCLUSION: The 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.

Anti-Inflammatory Effects of a Cordyceps sinensis Mycelium Culture Extract (Cs-4) on Rodent Models of Allergic Rhinitis and Asthma.

Allergic rhinitis and asthma are common chronic allergic diseases of the respiratory tract, which are accompanied by immunoglobulin E (IgE)-mediated inflammation and the involvement of type 2 T helper cells, mast cells, and eosinophils. Cordyceps sinensis (Berk.) Sacc is a fungal parasite on the larva of Lepidoptera. It has been considered to be a health-promoting food and, also, one of the best-known herbal remedies for the treatment of airway diseases, such as asthma and lung inflammation. In the present study, we demonstrated the antiallergic rhinitis effect of Cs-4, a water extract prepared from the mycelium culture of Cordyceps sinensis (Berk) Sacc, on ovalbumin (OVA)-induced allergic rhinitis in mice and the anti-asthmatic effect of Cs-4 in a rat model of asthma. Treatment with Cs-4 suppressed the nasal symptoms induced in OVA-sensitized and challenged mice. The inhibition was associated with a reduction in IgE/OVA-IgE and interleukin (IL)-4/IL-13 levels in the nasal fluid. Cs-4 treatment also decreased airway responsiveness and ameliorated the scratching behavior in capsaicin-challenged rats. It also reduced plasma IgE levels, as well as IgE and eosinophil peroxidase levels, in the bronchoalveolar fluid. Cs-4 treatment completely suppressed the increases in IL-4, IL-5, and IL-13 levels in rat lung tissue. In conclusion, our results suggest that Cs-4 has the potential to alleviate immune hypersensitivity reactions in allergic rhinitis and asthma.

Extract of Boehmeria nivea Suppresses Mast Cell-Mediated Allergic Inflammation by Inhibiting Mitogen-Activated Protein Kinase and Nuclear Factor-κB.

Mast cells are effector cells that initiate allergic inflammatory immune responses by inducing inflammatory mediators. Boehmeria nivea (Linn.) Gaudich is a natural herb in the nettle family Urticaceae that possesses numerous pharmacological properties. Despite the various pharmacological benefits of Boehmeria nivea, its effects on allergic inflammation have not yet been determined. Here, we investigated the effect of the ethanol extract of Boehmeria nivea (BNE) on degranulation rat basophilic leukemia (RBL)-2H3 mast cells stimulated with anti-dinitrophenyl (anti-DNP) and bovine serum albumin (BSA) during immunoglobulin E (IgE)-mediated allergic immune response. The results showed inhibition of the release of ß-hexosaminidase and histamine from the cells. BNE suppressed pro-inflammatory cytokines (Tumor necrosis factor (TNF)-α, Interleukin (IL)-1ß, and IL-6) and reduced T helper (Th)2 cytokine IL-4 expression and/or secretion correlated with the downregulation of p38, extracellular signal-regulated kinases (ERK) mitogen-activated protein kinase (MAPK), and nuclear factor-κB (NF-κB) signaling pathways in treated RBL-2H3 mast cells. In passive cutaneous anaphylaxis, treatment with BNE during IgE-mediated local allergic reaction triggered a reduction in mouse ear pigmentation and thickness. Taken together, these results indicated that BNE suppressed mast cell-mediated inflammation, suggesting that BNE might be a candidate for the treatment of various allergic disorders.

Protective Effect of GHX02 Extract on Particulate Matter-Induced Lung Injury.

Industrial development, along with the rapid growth of the economy, has greatly improved the quality of life in humans. Moreover, advancements in medical technology have increased life expectancy. Small particles increase airway inflammation when they penetrate the alveoli. We observed that GHX02 decreased the frequency and delayed the onset time of citric acid-induced coughing in guinea pigs. A phenol red secretion assay indicated that the GHX02 extract exhibits potent expectorant activity. The GHX02 extract also greatly reduced leukocyte levels. Our results indicate that GHX02 inhibits airway inflammation, reduces sputum production, and relieves cough. The GHX02 extract suppressed histamine release from mast cells resulting from compound 48/80-induced degranulation. The extract exhibited antimicrobial activity against Streptococcus pneumoniae and significantly inhibited the formation of LTC4. At high concentrations, the GHX02 extract suppressed the formation of PGE2 (prostaglandin E2). Interleukin (IL)-4 and IL-13 levels decreased with an increasing dosage of GHX02. Oral administration of the GHX02 extract suppressed PM10D-induced inflammatory symptoms in the lung, including increased alveolar wall thickness, accumulation of collagen fibers, and cytokine release. Treatment with the GHX02 extract also resulted in lower levels of inflammatory cells, in bronchoalveolar lavage fluid and lung tissue. Our results indicate that GHX02 may be a useful therapeutic agent for treatment of respiratory diseases.

Grifola frondosa extract and ergosterol reduce allergic reactions in an allergy mouse model by suppressing the degranulation of mast cells.

The increasing number of patients suffering from allergic diseases is a global health problem. Grifola frondosa is an edible mushroom consumed as a health food in Asia, and has recently been reported to have anti-allergic effects. We previously reported that G. frondosa extract (GFE) and its active components, ergosterol and its derivatives, inhibited the antigen-induced activation of RBL-2H3 cells. Here, we demonstrated that GFE and ergosterol also had an inhibitory effect on the degranulation of bone marrow-derived mast cells (BMMCs) and alleviated anaphylactic cutaneous responses in mice. Using an air pouch-type allergic inflammation mouse model, we confirmed that oral administration of GFE and ergosterol suppressed the degranulation of mast cells in vivo. Our findings suggest that G. frondosa, including ergosterol as its active component, reduces type I allergic reactions by suppressing mast cell degranulation in mice, and might be a novel functional food that prevents allergic diseases.

Hispidulin Inhibits Mast Cell-Mediated Allergic Inflammation through Down-Regulation of Histamine Release and Inflammatory Cytokines.

Hispidulin (4',5,7-trihydroxy-6-methoxyflavone) is a natural compound derived from traditional Chinese medicinal herbs, and it is known to have an anti-inflammatory effect. Here, we investigated the effect of hispidulin on the immunoglobulin E (IgE)-mediated allergic responses in rat basophilic leukemia (RBL)-2H3 mast cells. When RBL-2H3 cells were sensitized with anti-dinitrophenyl (anti-DNP) IgE and subsequently stimulated with DNP-human serum albumin (HSA), histamine and ß-hexosaminidase were released from the cells by degranulation of activated mast cells. However, pretreatment with hispidulin before the stimulation of DNP-HSA markedly attenuated release of both in anti-DNP IgE-sensitized cells. Furthermore, we investigated whether hispidulin inhibits anti-DNP IgE and DNP-HSA-induced passive cutaneous anaphylaxis (PCA), as an animal model for Type I allergies. Hispidulin markedly decreased the PCA reaction and allergic edema of ears in mice. In addition, activated RBL-2H3 cells induced the expression of inflammatory cytokines (tumor necrosis factor-α and interleukin-4), which are critical for the pathogenesis of allergic disease, through the activation of c-Jun N-terminal kinase (JNK). Inhibition of JNK activation by hispidulin treatment reduced the induction of cytokine expression in the activated mast cells. Our results indicate that hispidulin might be a possible therapeutic candidate for allergic inflammatory diseases through the suppression of degranulation and inflammatory cytokines expression.

Flos Magnoliae Inhibits Chloride Secretion via ANO1 Inhibition in Calu-3 Cells.

Flos Magnoliae (FM, Chinese name: Xin-yi) is an oriental medicinal herb commonly used for symptomatic relief from allergic rhinitis, sinusitis, and headache, including in traditional Chinese and Korean medicine formulations. FM inhibits histamine release from mast cells and cytokine secretion from T cells. However, the mechanism of action of FM on the anoctamin-1 (ANO1) ion channel, which is responsible for nasal hypersecretion in allergic rhinitis, has not been elucidated. Therefore, in this study, we investigated the effect of a 30% ethanolic extract of FM (FMEtOH) and its chemical constituents on ANO1 activity. We used high-performance liquid chromatography analysis to identify five major chemical constituents of FMEtOH: vanillic acid, tiliroside, eudesmin, magnolin, and fargesin. Using a conventional whole-cell patch clamp method, we found that FMEtOH (30, 100, and 300[Formula: see text][Formula: see text]g/mL) and its chemical constituent tiliroside inhibited ANO1 activity in ANO1-overexpressing HEK293T cells. In addition, we found that the treatment of the airway epithelial cell line Calu-3 with interleukin 4 significantly increased Ca[Formula: see text] activated Cl[Formula: see text] current (ICaCC), but not cystic fibrosis transmembrane conductance regulator (CFTR)-mediated chloride current (ICFTR). FMEtOH and tiliroside specifically inhibited ICaCC. Thus, in this study, we identified a novel mechanism underlying the alleviation of allergic rhinitis by FMEtOH. Our results indicate that FMEtOH and its chemical constituent tiliroside are promising and potent agents for the prevention and treatment of allergic rhinitis.

Ergosterol and its derivatives from Grifola frondosa inhibit antigen-induced degranulation of RBL-2H3 cells by suppressing the aggregation of high affinity IgE receptors.

Grifola frondosa is an edible mushroom consumed as a health food and/or traditional medicine in Asia. However, the anti-allergic effects of G. frondosa are not yet understood. In this study, we demonstrated the effects of G. frondosa extract (GFE) on IgE-mediated allergic responses, using antigen-stimulated RBL-2H3 cells. Three active compounds: ergosterol, 6ß-methoxyergosta-7,22-dien-3ß,5α-diol (MEDD), and 6-oxoergosta-7,22-dien-3ß-ol (6-OXO) were isolated from GFE and shown to inhibit the antigen-induced release of ß-hexosaminidase and histamine. Among the three active components, we focused on ergosterol because of its high content in GFE. Ergosterol inhibited the aggregation of high-affinity IgE receptor (FcεRI), which is the first step in the activation of mast cells and antigen-induced tyrosine phosphorylation. Furthermore, ergosterol suppressed antigen-increased IL-4 and TNF-α mRNA. Taken together, our findings suggest that G. frondosa, including ergosterol and its derivatives as active components, has the potential to be a novel functional food that prevents type I allergies.

A high expression Mas-related G protein coupled receptor X2 cell membrane chromatography coupled with liquid chromatography and mass spectrometry method for screening potential anaphylactoid components in kudiezi injection.

Kudiezi injection is a traditional Chinese medicine injection used widely in China to alleviate blood stasis and to stimulate blood circulation. Its use has been associated with a high rate of adverse effects including anaphylactoid reactions. In the present study, a two-dimensional system comprised of high expression Mas-related G protein-coupled receptor X2 cell membrane chromatography coupled online with HPLC-ESI-IT-TOF-MS was established, and used to screen and identify anaphylactoid components in kudiezi injection. Luteolin-7-O-glucuronide, apigenin-7-O-glucronide, luteoloside and luteolin were identified as the potential anaphylactoid components. The release of ß-hexosaminidase and histamine from Laboratory of Allergic Disease 2 cells enabled evaluation of the anaphylactoid activities of these compounds in vitro. Both ß-hexosaminidase and histamine release were enhanced markedly with increasing concentrations of the anaphylactoid components. The molecular docking assay showed excellent interactions between the potential anaphylactoid constituents and MRGPRX2. In general, the two-dimensional system developed in this study is effective in screening for the anaphylactoid components in Kudiezi injection.

Eupatilin suppresses the allergic inflammatory response in vitro and in vivo.

INTRODUCTION: Eupatilin, a pharmacologically active ingredient found in Artemisia asiatica, has been reported to have anti-oxidative, anti-inflammatory, and anti-apoptotic activities. However, molecular mechanisms underlying its anti-allergic properties are not yet clear. In this study, we investigated the effects of eupatilin on allergic inflammation in phorbol 12-myristate 13-acetate plus calcium ionophore A23187 (PMACI)-stimulated human mast cells and a compound 48/80-induced anaphylactic shock model. METHODS: Cytokine assays, histamine assays, quantitative real-time polymerase chain reaction analysis, western blot analysis and compound 48/80-induced anaphylactic shock model were used in this study. RESULTS: Eupatilin significantly suppresses the expression and production of pro-inflammatory cytokines, such as interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, and IL-6 in vitro and in vivo. In addition, eupatilin inhibits nuclear factor kappa B (NF-κB) activation by regulating the phosphorylation and degradation of IκBα via the Akt/IKK(α/ß) pathway. Eupatilin treatment also attenuates the phosphorylation of p38, ERK, and JNK MAPKs. Furthermore, eupatilin blocked anaphylactic shock and decreased the release of histamine. CONCLUSIONS: Anti-allergic inflammation may involve the expression and production of regulating pro-inflammatory cytokines via Akt/IKK(α/ß) and MAPK activation of NF-κB. On the basis of these data, eupatilin is a potential candidate for the treatment of allergic diseases.

Mast cells are important regulator of acupoint sensitization via the secretion of tryptase, 5-hydroxytryptamine, and histamine.

Mast cells (MCs) play a crucial role in mediating the establishment of networks among the circulatory, nervous and immune system at acupoints. However, the changes which occur in MCs during acupoint sensitization, i.e. the dynamic transformation of an acupoint from a "silenced" to an "activated" status, remain uncharacterized. To investigate the morphological and functional changes of MCs as an aid to understanding the cellular mechanism underlying acupoint sensitization, a rat model of knee osteoarthritis (OA) was induced by an injection of mono-iodoacetate (MIA) on day 0. On day 14, toluidine blue and immunofluorescence staining were used to observe the recruitment and degranulation of MCs and the release of mast cell co-expressed mediators: tryptase, 5-hydroxytryptamine (5-HT) and histamine (HA) at the acupoints Yanglingquan (GB34), Heding (EX-LE2) and Weizhong (BL40). Results showed that the number of MCs as well as the percentages of degranulated and extensively degranulated MCs at the acupoints GB34 and EX-LE2 in the light (A), mild (B), heavy (C) osteoarthritis groups were larger than those in the normal control (N) and normal saline (NS) groups (p < 0.01). Comparisons among the A, B and C groups suggested that the number and the degranulation extent of the MCs at the acupoints GB34 and EX-LE2 were positively correlated with the severity of the disease. Some MCs in the A, B and C group showed the release of 5-HT, HA, and tryptase in degranulation at the acupoints GB34 and EX-LE2. Such changes in MCs were not observed at the acupoint BL40. In conclusion, this study confirmed that acupoint sensitization is associated with the increase in recruitment and degranulation levels of MCs on a acupoint-specific and disease severity-dependent manner. The release of tryptase, 5-HT, and HA during MC degranulation is likely to be one of the cellular mechanisms occurring during acupoint sensitization.

Sinomenine-induced histamine release-like anaphylactoid reactions are blocked by tranilast via inhibiting NF-κB signaling.

Zhengqing Fengtongning (ZQFTN), the pharmaceutical preparation of sinomenine (SIN) derived from the medicinal plant Sinmenium acutum, is well-known in China as an effective treatment for rheumatoid arthritis (RA). However, its histamine-release anaphylactoid reactions (HRARs) occur often in some patients. Therefore, it is desirable to establish effective clinical protocols to manage such HRARs. In the study, rat models with systemic HRARs and local HRARs of the skin were established. The level of vascular permeability and mast cell numbers was determined by quantitative analysis using Evans blue dye and histological assays. The levels of histamine, leukotriene B4 (LTB4) and IL-33 in plasma were detected by UHPLC-SPE-MS, ELISA and immunohistochemistry assays, respectively. The results demonstrated that SIN significantly induced both systemic and local HRARs in rats, showing significant decrease of body temperature, increases in vascular permeability in skin, injury of lung tissues and mast cell infiltration and IL-33 expression in skin and lung tissues. Mechanistic study showed that tranilast could prevent SIN-triggered HRARs via inhibition of H1 receptor gene expression and NF-κB signaling. Our findings provide evidence that mast cell membrane stabilizers and H1 receptor blockers effectively prevent SIN-induced HRARs, and cromolyn, cetirizine and tranilast can be used in the clinic for the management of HRARs induced by ZQFTN.

Allergens in red ginseng extract induce the release of mediators associated with anaphylactoid reactions.

BACKGROUND: Anaphylactoid reactions induced by preparations containing red ginseng have been reported. The aim of this study is to evaluate the allergenicity and screen potential allergens in red ginseng extract thoroughly. METHODS: Red ginseng extract (RGE) and different fractions of RGE were prepared and evaluated by measuring the degranulation and viability of rat basophilic leukemia 2H3 (RBL-2H3) cells. Potential allergens were screened by RBL-2H3 cell extraction and allergenicity verified in RBL-2H3 cells, mouse peritoneal mast cells, Laboratory of Allergic Disease 2 (LAD2) human mast cells and mice, respectively. RESULTS: 80% ethanol extract of red ginseng extract induced mast cell degranulation with less cytotoxicity, but 40% ethanol extract could not. Ginsenoside Rd and 20(S)-Rg3 could induce a significant increase in ß-hexosaminidase release, histamine release and translocation of phosphatidylserine in RBL-2H3 cells. Ginsenoside Rd and 20(S)-Rg3 also increased ß-hexosaminidase release and the intracellular Ca2+ concentration in mouse peritoneal mast cells and LAD2 cells. In addition, histamine levels in serum of mice were elevated dose-dependently. CONCLUSIONS: Ginsenoside Rd and 20(S)-Rg3 are potential allergens that induce the release of mediators associated with anaphylactoid reactions. Our study could guide optimization of methods associated with Rd/20(S)-Rg3-containing preparations and establishment of quality standards for safe application of Traditional Chinese Medicines.