Bergapten inhibits airway inflammation and MRGPRX2-mediated mast cells activation by targeting NR4A1.

Asthma is a serious global health problem affecting 300 million persons around the world. Mast cells (MCs) play a major role in airway hyperresponsiveness (AHR) and inflammation in asthma, their exact effector mechanisms remain unclear. Here, we aim to investigate the inhibitory effect of Bergapten (BER) on MRGPRX2-mediated MCs activation through asthma model. Mouse model of asthma was established to examine the anti-asthmatic effects of BER. Calcium (Ca2+) influx, ß-hexosaminidase and histamine release were used to assess MCs degranulation in vitro. RNA-Seq technique was conducted to study the gene expression profile. RT-PCR and Western Blotting were performed to examine targeting molecules expression. BER inhibited AHR, inflammation, mucous secretion, collagen deposition and lung MCs activation in asthma model. BER dramatically reduced levels of IL4, IL-5, and IL-13 in bronchoalveolar lavage fluid (BALF), as well as inflammatory cells. BER also reduced serum IgE levels. Pretreatment MCs with BER inhibited substance P (SP)-induced Ca2+ influx, degranulation and cytokines release from MCs. BER also reduced the phosphorylation levels of PKC, PLC, IP3R, AKT and ERK, which were induced by SP. Furthermore, RNA-seq analysis showed that SP up-regulated 68 genes in MCs, while were reversed by BER. Among these 68 genes, SP up-regulated NR4A1 expression, and this effect was inhibited by BER. Meanwhile, knockdown of NR4A1 significantly attenuated SP-induced MCs degranulation. In conclusion, NR4A1 plays a major role in MRGPRX2-mediated MCs activation, BER inhibited AHR and inflammation in asthmatic model by inhibiting MCs activation through MRGPRX2-NR4A1 pathway.

Activation of Mast Cells by Neuropeptides: The Role of Pro-Inflammatory and Anti-Inflammatory Cytokines.

Mast cells (MCs) are tissue cells that are derived from bone marrow stem cells that contribute to allergic reactions, inflammatory diseases, innate and adaptive immunity, autoimmunity, and mental disorders. MCs located near the meninges communicate with microglia through the production of mediators such as histamine and tryptase, but also through the secretion of IL-1, IL-6 and TNF, which can create pathological effects in the brain. Preformed chemical mediators of inflammation and tumor necrosis factor (TNF) are rapidly released from the granules of MCs, the only immune cells capable of storing the cytokine TNF, although it can also be produced later through mRNA. The role of MCs in nervous system diseases has been extensively studied and reported in the scientific literature; it is of great clinical interest. However, many of the published articles concern studies on animals (mainly rats or mice) and not on humans. MCs are known to interact with neuropeptides that mediate endothelial cell activation, resulting in central nervous system (CNS) inflammatory disorders. In the brain, MCs interact with neurons causing neuronal excitation with the production of neuropeptides and the release of inflammatory mediators such as cytokines and chemokines. This article explores the current understanding of MC activation by neuropeptide substance P (SP), corticotropin-releasing hormone (CRH), and neurotensin, and the role of pro-inflammatory cytokines, suggesting a therapeutic effect of the anti-inflammatory cytokines IL-37 and IL-38.

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

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

Th2 high and mast cell gene signatures are associated with corticosteroid sensitivity in COPD.

RATIONALE: Severe asthma and chronic obstructive pulmonary disease (COPD) share common pathophysiological traits such as relative corticosteroid insensitivity. We recently published three transcriptome-associated clusters (TACs) using hierarchical analysis of the sputum transcriptome in asthmatics from the Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes (U-BIOPRED) cohort comprising one Th2-high inflammatory signature (TAC1) and two Th2-low signatures (TAC2 and TAC3). OBJECTIVE: We examined whether gene expression signatures obtained in asthma can be used to identify the subgroup of patients with COPD with steroid sensitivity. METHODS: Using gene set variation analysis, we examined the distribution and enrichment scores (ES) of the 3 TACs in the transcriptome of bronchial biopsies from 46 patients who participated in the Groningen Leiden Universities Corticosteroids in Obstructive Lung Disease COPD study that received 30 months of treatment with inhaled corticosteroids (ICS) with and without an added long-acting ß-agonist (LABA). The identified signatures were then associated with longitudinal clinical variables after treatment. Differential gene expression and cellular convolution were used to define key regulated genes and cell types. MEASUREMENTS AND MAIN RESULTS: Bronchial biopsies in patients with COPD at baseline showed a wide range of expression of the 3 TAC signatures. After ICS±LABA treatment, the ES of TAC1 was significantly reduced at 30 months, but those of TAC2 and TAC3 were unaffected. A corticosteroid-sensitive TAC1 signature was developed from the TAC1 ICS-responsive genes. This signature consisted of mast cell-specific genes identified by single-cell RNA-sequencing and positively correlated with bronchial biopsy mast cell numbers following ICS±LABA. Baseline levels of gene transcription correlated with the change in RV/TLC %predicted following 30-month ICS±LABA. CONCLUSION: Sputum-derived transcriptomic signatures from an asthma cohort can be recapitulated in bronchial biopsies of patients with COPD and identified a signature of airway mast cells as a predictor of corticosteroid responsiveness.

Adefovir accumulation in the renal interstitium triggers mast cell degranulation and promotes renal interstitial fibrosis.

Organic anion transporters 1 (OAT1) and OAT3 are responsible for transporting adefovir (ADV) into renal tubular epithelial cells. Our previous research found that ADV accumulated in the renal interstitium and caused renal interstitial fibrosis when Oat1/3 were inhibited by OATs inhibitor probenecid for long-term. Mast cells (MCs) in the interstitial space are considered to be key drivers of renal fibrosis. The current work investigated the effect of ADV on MCs in vitro and during the development of interstitial fibrosis in rats. Results indicate that ADV triggers chymase release from cultured RBL-2H3 mast cells in a time-and concentration-dependent manner. Angiotensin II (Ang II) in renal interstitium is generated mainly by chymase, renin and other products released from MCs, and has a direct effect on fibrosis through the angiotensin receptor. The concentrations of Ang II and fibrosis was significantly increased after administration of ADV alone or with probenecid for 4 weeks. The MCs membrane stabilizer sodium cromoglycate (SCG) and the angiotensin receptor antagonist Valsartan (VAL) could ameliorate ADV-induced nephrotoxicity. Additionally, SCG or VAL could reduce the accumulation of ADV in the renal interstitium by upregulating the expression of Oat1/3 and multidrug resistance-associated protein 4. Therefore, ADV accumulation in the renal interstitium could promote the degranulation of interstitial MCs and drive the development of renal fibrosis. SCG or VAL could ameliorate ADV-associated fibrosis by decreasing degranulation of MCs and accelerating renal clearance of ADV.

Resveratrol Treatment Prevents Increase of Mast Cells in Both Murine OVA Enteritis and IL-10-/- Colitis.

Mast cells are involved in allergic and other inflammatory diseases. The polyphenol resveratrol is known for its anti-inflammatory properties and may be used as nutraceutical in mast cell associated diseases. We analyzed the effect of resveratrol on mast cells in vivo in ovalbumin-induced allergic enteritis as well as experimental colitis in IL-10-/- mice which received resveratrol via drinking water. Treatment with resveratrol prevented the increase in mast cells in both allergic enteritis and chronic colitis in duodenum as well as in colon. Further, it delayed the onset of diseases symptoms and ameliorated diseases associated parameters such as tissue damage as well as inflammatory cell infiltration in affected colon sections. In addition to the findings in vivo, resveratrol inhibited IgE-dependent degranulation and expression of pro-inflammatory cytokines such as TNF-α in IgE/DNP-activated as well as in LPS-activated bone marrow-derived mast cells. These results indicate that resveratrol may be considered as an anti-allergic and anti-inflammatory plant-derived component for the prevention or treatment of mast cell-associated disorders of the gastrointestinal tract.

Anti-KIT monoclonal antibody CDX-0159 induces profound and durable mast cell suppression in a healthy volunteer study.

BACKGROUND: Mast cells (MC) are powerful inflammatory immune sentinel cells that drive numerous allergic, inflammatory, and pruritic disorders when activated. MC-targeted therapies are approved in several disorders, yet many patients have limited benefit suggesting the need for approaches that more broadly inhibit MC activity. MCs require the KIT receptor and its ligand stem cell factor (SCF) for differentiation, maturation, and survival. Here we describe CDX-0159, an anti-KIT monoclonal antibody that potently suppresses MCs in human healthy volunteers. METHODS: CDX-0159-mediated KIT inhibition was tested in vitro using KIT-expressing immortalized cells and primary human mast cells. CDX-0159 safety and pharmacokinetics were evaluated in a 13-week good laboratory practice (GLP)-compliant cynomolgus macaque study. A single ascending dose (0.3, 1, 3, and 9 mg/kg), double-blinded placebo-controlled phase 1a human healthy volunteer study (n = 32) was conducted to evaluate the safety, pharmacokinetics, and pharmacodynamics of CDX-0159. RESULTS: CDX-0159 inhibits SCF-dependent KIT activation in vitro. Fc modifications in CDX-0159 led to elimination of effector function and reduced serum clearance. In cynomolgus macaques, multiple high doses were safely administered without a significant impact on hematology, a potential concern for KIT inhibitors. A single dose of CDX-0159 in healthy human subjects was generally well tolerated and demonstrated long antibody exposure. Importantly, CDX-0159 led to dose-dependent, profound suppression of plasma tryptase, a MC-specific protease associated with tissue MC burden, indicative of systemic MC suppression or ablation. CONCLUSION: CDX-0159 administration leads to systemic mast cell ablation and may represent a safe and novel approach to treat mast cell-driven disorders.

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.

Tanshinone IIA alleviates ovalbumin-induced allergic rhinitis symptoms by inhibiting Th2 cytokine production and mast cell histamine release in mice.

CONTEXT: Studies have shown that tanshinone IIA (TIIA) has an anti-inflammatory effect, but the effect on allergic rhinitis (AR) is unclear. OBJECTIVE: In this study, we explore the effect of TIIA on AR. MATERIALS AND METHODS: AR mice model was established by the intraperitoneal (ip) injection of 50 µg ovalbumin (OVA). AR mice in the dose tested groups were treated with TIIA (10 mg/kg/d, ip) or dexamethasone (Dex) (2.5 mg/kg/d, oral). The number of nasal rubbing in mice was counted. Inflammatory, goblet and mast cells in nasal mucosal tissue were detected. The contents of histamine, OVA-immunoglobulin E (IgE), OVA-immunoglobulin G1 (IgG1), tumour necrosis factor-α (TNF-α), interleukin-4 (IL-4), IL-5, interferon-γ (IFN-γ) and IL-12 in nasal lavage fluid (NALF) or serum were measured. Human mast cells (HMC-1) were treated with C48/80 to release histamine or TIIA for therapeutic effect, and the cell viability, histamine content and mast cell degranulation were examined. RESULTS: OVA promoted the number of nasal rubbings in mice (78 times/10 min, p< 0.001), increased the inflammatory, goblet and mast cells in nasal mucosal tissue, and significantly (p< 0.001) elevated the levels of histamine (120 ng/mL), OVA-IgE (2 pg/mL), OVA-IgG1 (90 ng/mL), TNF-α (2.3 pg/mL), IL-4 (150 pg/mL) and IL-5 (65 pg/mL) in serum or NALF of OVA-induced AR mice. However, both TIIA and Dex inhibited the effect of OVA on AR mice. Besides, TIIA reversed the promotion of histamine release (30%) and mast cell degranulation induced by C48/80. DISCUSSION AND CONCLUSIONS: TIIA alleviates OVA-induced AR symptoms in AR mice, and may be applied as a therapeutic drug for patients with Th2-, or mast cell-allergic disorders.

The Alleviating Effect of Lagerstroemia indica Flower Extract on Stretch Marks through Regulation of Mast Cells.

Striae distensae (SD) or stretch marks are common linear scars of atrophic skin with disintegrating extracellular matrix (ECM) structures. Although fibroblasts contribute to the construction of ECM structure in SD, some studies have reported that mast cell degranulation causes the disruption of ECM in early SD lesions. Lagerstroemia indica flower (LIF) has traditionally been used in India as a diuretic. However, little is known about the effect and molecular action of Lagerstroemia indica flower extract (LIFE) on alleviating SD. This study evaluated the effects of LIFE on mast cell degranulation and the synthesis of ECM components in fibroblasts. LIFE inhibits the adhesion of rat basophilic leukemia (RBL) cells, RBL-2H3 on fibronectin (FN) and the expression of integrin, a receptor for FN, thereby reducing focal adhesion kinase (FAK) phosphorylation. In addition, LIFE attenuated the allergen-induced granules and cytokine interleukin 3 (IL-3) through the adhesion with FN. Moreover, the conditioned medium (CM) of activated mast cells decreases the synthesis of ECM components, and LIFE restores the abnormal expressions induced by activated mast cells. These results demonstrate that LIFE suppresses FN-induced mast cell activation and promotes the synthesis of ECM components in fibroblast, which indicates that LIFE may be a useful cosmetic agent for SD treatment.

Pharmacological screening of Acalypha indica L.: Possible role in the treatment of asthma.

ETHNOPHARMACOLOGICAL RELEVANCE: Acalypha indica Linn (Euphorbiaceae), a popular traditional medicine, is an erect herb found throughout various parts of India. In Ayurveda, Acalypha indica was commonly used in asthma and allergy. However, no attempts were made in past to validate the antiasthmatic potential of Acalypha indica. AIM OF THE STUDY: The present study was aimed to assess the anti-asthmatic potential of ethanolic extracts of Acalypha indica leaves (EAIL) using various experimental animal models. MATERIALS AND METHODS: EAIL was analyzed using different screening methods such as acetylcholine and histamine-induced contraction of goat tracheal chain, clonidine-induced catalepsy in mice, milk-induced leucocytosis and eosinophilia in mice, clonidine-induced mast cell degranulation in rats, passive paw anaphylaxis in rats, histamine-induced bronchoconstriction in guinea pigs, and ovalbumin (OVA)-induced histopathological alterations in mice. RESULTS: Data received in the present study showed that EAIL drastically antagonized acetylcholine and histamine-induced contraction of goat tracheal chain, suggesting its anticholinergic and antihistaminic activity respectively. The duration of immobility, produced by clonidine, was found to be decreased in mice which showed its H1 receptor blocking activity. In milk-induced leucocytosis and eosinophilia in mice, EAIL significantly reduced the number of leucocytes and eosinophils suggesting its adaptogenic and anti-allergic potential. Inhibition of clonidine-induced mast cell degranulation in rats displayed its mast cell stabilizing potential. Reduction of paw edema in passive paw anaphylaxis exhibited antianaphylactic activity of EAIL. Guinea pigs were protected from histamine-induced bronchoconstriction by EAIL which revealed its bronchodilator potential. Furthermore, the histopathological architecture of lung tissue was near to normal. CONCLUSION: Our results contribute towards validation of the traditional use of Acalypha indica in the treatment of asthma due to the presence of a wide range of phytoconstituents. Hence our investigation revealed that EAIL possessed strong antiasthmatic property by virtue of various mechanisms.

Anti-Allergic Effect of 3,4-Dihydroxybenzaldehyde Isolated from Polysiphonia morrowii in IgE/BSA-Stimulated Mast Cells and a Passive Cutaneous Anaphylaxis Mouse Model.

In this study, we investigated the anti-allergic effects of 3,4-dihydroxybenzaldehyde (DHB) isolated from the marine red alga, Polysiphonia morrowii, in mouse bone-marrow-derived cultured mast cells (BMCMCs) and passive cutaneous anaphylaxis (PCA) in anti-dinitrophenyl (DNP) immunoglobulin E (IgE)-sensitized mice. DHB inhibited IgE/bovine serum albumin (BSA)-induced BMCMCs degranulation by reducing the release of ß-hexosaminidase without inducing cytotoxicity. Further, DHB dose-dependently decreased the IgE binding and high-affinity IgE receptor (FcεRI) expression and FcεRI-IgE binding on the surface of BMCMCs. Moreover, DHB suppressed the secretion and/or the expression of the allergic cytokines, interleukin (IL)-4, IL-5, IL-6, IL-13, and tumor necrosis factor (TNF)-α, and the chemokine, thymus activation-regulated chemokine (TARC), by regulating the phosphorylation of IκBα and the translocation of cytoplasmic NF-κB into the nucleus. Furthermore, DHB attenuated the passive cutaneous anaphylactic (PCA) reaction reducing the exuded Evans blue amount in the mouse ear stimulated by IgE/BSA. These results suggest that DHB is a potential therapeutic candidate for the prevention and treatment of type I allergic disorders.

Modulation of mTOR signaling by radiation and rapamycin treatment in canine mast cell cancer cells.

Rapamycin has been reported to reduce cancer cell survival in certain tumors following radiation therapy, but the mechanisms driving this phenomenon are unclear. Rapamycin inhibits mTOR signaling, a pathway responsible for several essential cell functions. The objective of this study was to investigate the effects of rapamycin and radiation on the activation and inhibition of mTOR signaling and the relationship between mTOR signaling and DNA damage response in vitro using canine mast cell tumor (MCT) cancer cell lines. Rapamycin rapidly inhibited S6K phosphorylation in a dose-dependent manner. Ionizing radiation (3, 6, or 10 Gy) was able to activate mTOR signalling, but the combination of radiation and rapamycin maintained mTOR inhibition. The comet assay revealed that co-treatment with rapamycin induced modest increases in the severity of DNA damage to MCT cells, but that these differences were not statistically significant. Although the relationship between mTOR and DNA damage response in MCT cancer cell lines remains unclear, our findings suggest the possibility of interaction, leading to enhancement of radiation response.

Il a été rapporté que la rapamycine réduisait la survie des cellules cancéreuses dans certaines tumeurs après une radiothérapie, mais les mécanismes à l'origine de ce phénomène ne sont pas clairs. La rapamycine inhibe la signalisation mTOR, une voie responsable de plusieurs fonctions cellulaires essentielles. L'objectif de cette étude était d'étudier les effets de la rapamycine et des radiations sur l'activation et l'inhibition de la signalisation mTOR et la relation entre la signalisation mTOR et la réponse aux dommages à l'ADN in vitro à l'aide de lignées cellulaires cancéreuses de tumeurs mastocytaires canines (MCT). La rapamycine a rapidement inhibé la phosphorylation de S6K de manière dose-dépendante. Le rayonnement ionisant (3, 6 ou 10 Gy) a pu activer la signalisation mTOR, mais la combinaison de rayonnement et de rapamycine a maintenu l'inhibition de mTOR. Le test des comètes a révélé que le co-traitement avec la rapamycine induisait des augmentations modestes de la gravité des dommages à l'ADN des cellules MCT, mais que ces différences n'étaient pas statistiquement significatives. Bien que la relation entre mTOR et la réponse aux dommages à l'ADN dans les lignées cellulaires cancéreuses MCT reste incertaine, nos résultats suggèrent la possibilité d'une interaction, conduisant à une amélioration de la réponse aux radiations.(Traduit par Docteur Serge Messier).

Effect of Ghrelin Intervention on the Ras/ERK Pathway in the Regulation of Heart Failure by PTEN.

OBJECTIVE: To study the possible mechanism of ghrelin in heart failure and how it works. METHOD: In vitro results demonstrated that ghrelin alleviates cardiac function and reduces myocardial fibrosis in rats with heart failure. Moreover, ghrelin intervention increased PTEN expression level and reduced ERK, c-jun, and c-Fos expression level; in vivo experiments demonstrated that ghrelin intervention reduces mast memory expression and increases cardiomyocyte surface area, PTEN expression level, ERK, c-jun, c-Fos expression level, and cell surface area, while ERK blockade suppresses mast gene expression and reduces cell surface area. RESULTS: In vitro experimental results prove that we have successfully constructed a rat model related to heart failure, and ghrelin can alleviate the heart function of heart failure rats and reduce myocardial fibrosis. In addition, ghrelin is closely related to the decrease of the expression levels of ERK, c-jun, and c-Fos, but it can also increase the expression of PTEN in the rat model; in vivo experiments proved that we successfully constructed an in vitro cardiac hypertrophy model, and the intervention of ghrelin would reduce the expression of hypertrophic memory and increase the surface area of cardiomyocytes, increase the expression level of PTEN, and reduce the expression levels of ERK, c-jun, and c-Fos, while the blockade of PTEN will increase the expression of hypertrophy genes and increase the cell surface area, while the blockade of ERK will increase the expression of hypertrophic genes, which in turn will make the cell surface area reducing. CONCLUSION: Ghrelin inhibits the phosphorylation and nuclear entry of ERK by activating PTEN, thereby controlling the transcription of hypertrophic genes, improving myocardial hypertrophy, and enhancing cardiac function.

Honokiol suppresses 2,6-dinitrochlorobenzene-induced atopic dermatitis in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Magnolia officinalis constitutes a traditional Korean medicine used for the treatment of atopic dermatitis, and honokiol is an active diphenyl compound present in Magnolia officinalis. AIM OF THE STUDY: The aim of the study was to investigate the therapeutic effects of honokiol on atopic dermatitis in vivo. MATERIALS AND METHODS: The therapeutic effects of honokiol were evaluated in a 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis model. RESULTS: Administration of honokiol (10 mg/kg) significantly suppressed mast cell accumulation and inflammation induced by DNCB in skin tissues. Moreover, DNCB-induced increases in serum immunoglobulin E levels were reversed by honokiol treatment. In addition, DNCB-induced elevation of inflammatory cytokines (interleukin (IL)-4, IL-13, IL-17, and interferon-γ) in the skin and lymph nodes was significantly ameliorated by honokiol administration. Furthermore, the increase in lymph nodes sizes induced by DNCB treatment was reduced by honokiol administration. CONCLUSION: DNCB-induced atopic responses in the ears and lymph nodes were significantly suppressed by honokiol treatment. These results suggested that honokiol is a potential therapeutic agent for atopic dermatitis.

Development of ProTx-II Analogues as Highly Selective Peptide Blockers of Nav1.7 for the Treatment of Pain.

Inhibitor cystine knot peptides, derived from venom, have evolved to block ion channel function but are often toxic when dosed at pharmacologically relevant levels in vivo. The article describes the design of analogues of ProTx-II that safely display systemic in vivo blocking of Nav1.7, resulting in a latency of response to thermal stimuli in rodents. The new designs achieve a better in vivo profile by improving ion channel selectivity and limiting the ability of the peptides to cause mast cell degranulation. The design rationale, structural modeling, in vitro profiles, and rat tail flick outcomes are disclosed and discussed.

Relationship of Notch Signal, Surfactant Protein A, and Indomethacin in Cervix During Preterm Birth: Mast Cell and Jagged-2 May Be Key in Understanding Infection-mediated Preterm Birth.

Although it is thought that there is a close relationship between Notch signal and preterm birth, the functioning of this mechanism in the cervix is unknown. The efficacy of surfactants and prostaglandin inhibitors in preterm labor is also still unclear. In this study, 48 female CD-1 mice were distributed to pregnant control (PC), Sham, PBS, indomethacin (2 mg/kg; intraperitoneally), lipopolysaccharides (LPS) (25 µg/100 µl; intrauterine), LPS + IND, and Surfactant Protein A Block (SP-A Block: SP-A B; the anti-SP-A antibody was applied 20 µg/100µl; intrauterine) groups. Tissues were examined by immunohistochemistry, immunofluorescence, and Western blot analysis. LPS administration increased the expression of N1 Dll-1 and Jagged-2 (Jag-2). Although Toll-like receptor (Tlr)-2 significantly increased in the LPS-treated and SP-A-blocked groups, Tlr-4 significantly increased only in the LPS-exposed groups. It was observed that Jag-2 is specifically expressed by mast cells. Overall, this experimental model shows that some protein responses increase throughout the uterus, starting at a specific point on the cervix epithelium. Surfactant Protein A, which we observed to be significantly reduced by LPS, may be associated with the regulation of the epithelial response, especially during preterm delivery due to infection. On the contrary, prostaglandin inhibitors can be considered an option to delay infection-related preterm labor with their dose-dependent effects. Finally, the link between mast cells and Jag-2 could potentially be a control switch for preterm birth.

The effects and the mechanisms of naringenin from Artemisia ordosica Krasch on allergic rhinitis based on mast cell degranulation model and network pharmacology.

OBJECTIVES: The ethyl acetate extraction of Artemisia ordosica Krasch (AOK) root showed anti-allergic rhinitis (AR) effect, while the active compounds and pharmacological targets were unknown. METHODS: The P815 degranulation was established by cell counting kit 8 assay, ß-hexosaminidase releasing assay and toluidine blue staining. The flavonoids were screened in vitro. Then toluidine blue staining and ELISA were carried out to investigate the anti-inflammatory effects of the active compound. Network pharmacology was implemented to explain the mechanisms of the active compound. iGEMDOCK was used to investigate the binding between active compound and hub targets. KEY FINDINGS: C48/80 was the optimum reagent in triggering P815 degranulation. Naringenin could significantly decrease P815 degranulation. Meanwhile, naringenin could remarkably increase the IL-4 and decrease the tumour necrosis factor-α. The effect of naringenin on AR was achieved by regulating multiple targets (e.g. AKT1, MAPK3, VEGFA) and pathways (e.g. pathways in cancer, VEGF signalling pathway). Nine hub proteins were obtained by topological analysis. Multiple hydrogen bonds and van der Waals forces were formed between the naringenin and the residues of hub proteins. CONCLUSIONS: Naringenin might be one of the effective ingredients of AOK against AR. And its effects could achieve through regulating multiple targets and pathways.

Iodixanol activation of mast cells: Implications in the pathogenesis of iodixanol-induced delayed cutaneous adverse reactions.

Iodinated contrast media (ICM) is widely used in radiological examination and interventional therapy. In the commonly used ICM, iodixanol is considered to be the safer one. However, compared with other ICMs, it has a higher incidence of delayed cutaneous adverse reactions. The underlying mechanisms are unclear. In this study, mice with positive allergic reactions were selected based on the mouse clinical allergy symptom score and skin and blood samples taken 1, 6, 24, 48, and 72 h after ICMs (6 g iodine/kg) injection for histological and blood analyses. ICMs-induced pseudo-allergic reactions were investigated through in vivo intravital vascular imaging and passive cutaneous anaphylaxis (PCA) not mediated by IgE and through, calcium imaging degranulation of mast cells (MCs), and western blot assays in vitro. Results shows iodixanol-induced systemic anaphylaxis caused severe extravasation of plasma proteins and degranulation of skin MCs, and increased levels of plasma histamine, cytokines and inflammatory chemokines. Mechanistically, iodixanol increases degranulation of MCs and promotes the synthesis of inflammatory factors by activating PLC-γ and PI3K-related pathways. Trigonelline inhibit iodixanol-induced MC-related pseudo-allergic reactions in vitro and in vivo. These results suggest that mice in the iodixanol group had a higher incidence of delayed cutaneous reactions, characterized by cytokine release over time and delayed cutaneous MC degranulation. Iodixanol's delayed cutaneous adverse reactions may be due to a delayed phase of MC-related pseudo-allergic reactions. Trigonelline revealed anti-allergic activity in iodixanol-induced MC-related pseudo-allergic reactions.

p-Phenylenediamine induces immediate contact allergy and non-histaminergic itch via MRGPRX2.

p-phenylenediamine (PPD) is a common component of hair dye known to induce immediate allergy, even acute dermatitis and contact dermatitis. MAS-related G protein coupled receptor-X2 (MRGPRX2) in mast cells (MCs) mediates small molecular substances-induced pseudo-allergic reactions. However, the role of MRGPRX2 in PPD-induced immediate contact allergy needs further exploration. The aim of this study was to investigate whether PPD activates MCs via MRGPRX2 and induces immediate allergies that contribute to contact dermatitis. Wild-type (WT) and kitw-sh/w-sh mice (MUT) were treated with PPD to observe local inflammation and MC degranulation in vivo. The release of inflammatory mediators was measured in vitro. Histamine 1 receptor (H1R)-/- mice were used to analyze itch type. PPD caused immediate contact allergy in WT mice, induced scratching, and local inflammatory reactions, while exhibiting minimal effects on MUT mice. PPD did not induce histamine release, but induced significant tryptase release in vivo and in vitro. PPD activated MRGPRX2 to induce MC degranulation in vitro. PPD caused immediate contact allergy in WT mice, induced scratching and local inflammatory reactions, while exhibited minimal effect on MUT mice. PPD did not induce histamine release, while induced significant tryptase release in vivo and in vitro. PPD induced immediate contact allergy by MCs activation via MRGPRX2 and lead to tryptase release. The scratching times showed no significant difference in WT mice or H1R-/- mice, which indicated PPD caused non-histaminergic itch. The results showed that PPD activated MCs via MRGPRX2 and induced immediate contact allergy, leading to the release of tryptase without monoamine release, which might induce non-histaminergic itch.