Mast Cell Degranulation Research Articles

Aloe-emodin relieves allergic contact dermatitis pruritus by inhibiting mast cell degranulation

Urushiol-induced allergic contact dermatitis (ACD) is a chronic inflammatory skin disease in which skin barrier dysfunction leads to pruritus and eczematous lesions. ACD is triggered by immune imbalance. Aloe emodin is an anthraquinone derivative extracted from rhubarb, aloe and other traditional Chinese medicines. It has a wide range of pharmacological effects, including anti-inflammatory, anti-tumor, and anti-allergic effects. The purpose of our study was to demonstrate the effectiveness of aloe-emodin on urushiol-induced acute pruritus and allergic contact dermatitis. The results showed that urushiol could stimulate keratinocytes to release chemokines CXCL1, CXCL2, CCL2, TSLP, and TNF-α, which recruit or activate mast cells. Aloe-emodin treatment inhibited inflammatory-response-induced mast cell degranulation in skin lesions and suppressed the expression of inflammatory cytokines, such as interleukin-4, and interleukin-6. Therefore, the results indicate that aloe-emodin can improve urushiol-induced acute pruritus and allergic contact dermatitis in mice by inhibiting mast cell degranulation.

Acupuncture at Weizhong (BL40) attenuates acetic acid-induced overactive bladder in rats by regulating brain neural activity through the modulation of mast cells and tibial nerves

ObjectiveThe present study evaluated the effects of deep acupuncture at Weizhong acupoint (BL40) on bladder function and brain activity in a rat model of overactive bladder (OAB), and investigated the possible mechanisms around the acupuncture area that initiate the effects of acupuncture. MethodsAdult female Sprague–Dawley rats were randomly divided into six groups, comprising a control group, model group, group treated with deep acupuncture at BL40, group treated with shallow acupuncture at BL40, group treated with acupuncture at non-acupoint next to BL40, and group treated with acupuncture at Xuanzhong (GB39). Urodynamic evaluation was used to observe the urination, and functional magnetic resonance imaging was used to observe the brain activation. The mechanism of acupuncture at BL40 in regulating bladder function was explored by toluidine blue staining and enzyme-linked immunosorbent assay, and the mechanism was verified by stabilizing mast cells (MCs) or blocking tibial nerve. ResultsDeep acupuncture at BL40 significantly increased the intercontraction interval in OAB rats and enhanced the mean amplitude of low frequency fluctuation of primary motor cortex (M1), periaquaductal gray matter (PAG), and pontine micturition center (PMC). It also increased the zero-lag functional connectivity between M1 and PAG and between PAG and PMC. Shallow acupuncture at BL40 and acupuncture at non-acupoint or GB39 had no effect on these indexes. Further studies suggested that deep acupuncture at BL40 increased the number and degranulation rate of MCs as well as the contents of 5-hydroxytryptamine, substance P, and histamine in the tissues around BL40. Blocking the tibial nerve by lidocaine injection or inhibiting MC degranulation by sodium cromoglycate injection obstructed the effects of acupuncture on restoring urinary function and modulating brain activation in OAB rats. ConclusionDeep acupuncture at BL40 may be more effective for inhibiting OAB by promoting degranulation of MCs around the acupoint and stimulating tibial nerve, thereby regulating the activation of the brain area that controls the lower urinary tract.

Effects of acupuncture needle modification on acupuncture analgesia

ObjectiveThe analgesic effect of acupuncture has been widely accepted. Nevertheless, the mechanism behind its analgesic effect remains elusive, thus impeding the progress of research geared toward enhancing the analgesic effect of acupuncture. This paper investigated the role of acupuncture needle surface textures on acupuncture’s analgesic effect by creating four experimental acupuncture needles with different patterns of surface augmentation. MethodsFour types of acupuncture needles with different surface textures (the lined needle, the circle needle, the sandpaper needle, and the threaded needle) were designed. Additionally, the force/torque measurement system used a robot arm and mechanical sensor to measure the force on the needle during insertion and manipulation. To perform acupuncture analgesia experiments, four experimental acupuncture needles and a normal needle were inserted into the Zusanli (ST36) acupoint of rats with inflammatory pain. By comparing the force and torque and the analgesic efficacy of the different acupuncture needles, these experiments tested the role of acupuncture needle body texture on acupuncture analgesia. ResultsThe analgesic effects of different acupuncture needle body textures varied. Specifically, the force required to penetrate the skin with the lined needle was not greater than that for the normal needle; however, the needle with inscribed circles and the sandpaper-roughened needle both required greater force for insertion. Additionally, the torque of the lined needle reached 2 ×10–4 N·m under twisting manipulation, which was four times greater the torque of a normal needle (5 × 10–5 N·m). Furthermore, the lined needle improved pain threshold and mast cell degranulation rate compared to the normal needle. ConclusionOptimizing the texture of acupuncture needles can enhance acupuncture analgesia. The texture of our experimental acupuncture needles had a significant impact on the force needed to penetrate the skin and the torque needed to manipulate the needle; it was also linked to variable analgesic effects. This study provides a theoretical basis for enhancing the analgesic efficacy of acupuncture through the modification of needles and promoting the development of acupuncture therapy.

RhoGDI in RBL-2H3 cells acts as a negative regulator of Rho GTPase signaling to inhibit granule exocytosis.

Mast cells are hematopoietic-derived immune cells that possess numerous cytoplasmic granules containing immune mediators such as cytokines and histamine. Antigen stimulation triggers mast cell granule exocytosis, releasing granule contents in a process known as degranulation. We have shown that Rho GTPase signaling is an essential component of granule exocytosis, however, the proteins that regulate Rho GTPases during this process are not well defined. Here we examined the role of Rho guanine-nucleotide dissociation inhibitors (RhoGDIs) in regulating Rho GTPase signaling using RBL-2H3 cells as a mast cell model. We found that RBL-2H3 cells express two RhoGDI isoforms which are primarily localized to the cytosol. Knockdown of RhoGDI1 and RhoGDI2 greatly reduced the levels of all Rho GTPases tested: RhoA, RhoG, Rac1, Rac2, and Cdc42. The reduction in Rho GTPase levels was accompanied by an increase in their membrane-localized fraction and an elevation in the levels of active Rho GTPases. All RhoGDI knockdown strains had altered resting cell morphology, although each strain was activation competent when stimulated. Live cell imaging revealed that the RhoGDI1/2 double knockdown (DKD) strain maintained its activated state for prolonged periods of time compared to the other strains. Only the RhoGDI1/2 DKD strain showed a significant increase in granule exocytosis. Conversely, RhoGDI overexpression in RBL-2H3 cells did not noticeably affect Rho GTPases or degranulation. Based on these results, RhoGDIs act as negative regulators of Rho GTPases during mast cell degranulation, and inhibit exocytosis by sequestering Rho GTPases in the cytosol.

Interleukin-33 mediated regulation of microRNAs in human cord blood-derived mast cells: Implications for infection, immunity, and inflammation.

Mast cell (MCs) activation is the driving force of immune responses in several inflammatory diseases, including asthma and allergies. MCs are immune cells found throughout the body and are equipped with numerous surface receptors that allow them to respond to external signals from parasites and bacteria as well as to intrinsic signals such as cytokines. Upon activation, MCs release various mediators and proteases that contribute to inflammation. This study aimed to identify microRNAs (miRNAs) that regulate MC response to interleukin-33 and their target genes using a model of human cord blood-derived mast cells (hCBMCs). hCBMCs were induced with 10 and 20 ng of recombinant human interleukin-33 (rhIL-33) for 6 and 24 h, respectively. Total RNA was extracted from these cells and miRNA profiling was performed using high-throughput microarrays. Differential expression of miRNAs and target analysis were performed using Transcriptome Analysis Console and Ingenuity Pathway Analysis. The most significant miRNAs in each condition were miR-6836-5p (fold change = 1.76, p = 3E-03), miR-6883-5p (fold change = -2.13, p = 7E-05), miR-1229-5p (fold change = 2.46, p = 8E-04), and miR-3613-5p (fold change = 66.7, p = 1E-06). Target analysis revealed that these miRNAs regulate mast cell responsiveness and degranulation by modulating the expression of surface receptors, adaptors, and signaling molecules in response to rhIL-33 stimulation. This study is the first miRNA profiling and target analysis of hCBMCs that will further enhance our understanding of the role of miRNAs in the immune response in a timely manner and their relevance for the development of a new therapeutic target for inflammatory disorders.

Retinol and Hydroxyasiaticoside Synergistically Relieve Histamine-Induced Atopic Dermatitis Activity by Repressing TRPV1, L1R1, and CD130 Targets

Background: Retinol, an important bioactive substance with multiple physiological functions such as promoting collagen synthesis, inhibiting matrix metalloproteinase activity, alleviating oxidative stress, regulating gene expression, and promoting epidermal cell proliferation, has a significant effect on skin damage recovery. Hydroxyasiaticoside, a triterpenoid saponin derived from Centella asiatica (L.) Urb., is closely related to the secretion of collagen types I and III, and possesses multiple biological activities, including moisturizing, antioxidants, anti-apoptosis, neuroprotection, anti-inflammation, and the promotion of wound healing. It plays a particularly prominent role in reducing oxidative stress in wounds and inducing vasodilatation. Objective: The aim of this study was to investigate the therapeutic efficacy of retinol combined with hydroxyasiaticoside in histamine-induced atopic dermatitis. Materials and Methods: The experiment was carried out using three different concentrations of a retinol and hydroxyasiaticoside mixed solution: low, medium, and high concentrations. After inducing atopic dermatitis in mice through histamine administration, these solutions were applied to the skin surface of the mice, and a comparative analysis was conducted with both the control group and the model group. The effect of combination therapy on atopic dermatitis was evaluated through histopathology, immunohistochemistry, and transcriptomic analysis. Results: The combination of retinol and hydroxyasiaticoside significantly attenuated histamine-induced scratching behaviors, alleviated the phenomenon of epidermal hyperplasia, and effectively reduced the proliferation, infiltration, and degranulation of mast cells. In addition, the combination inhibited the expression of relevant pro-inflammatory cytokines. Quantitative RNA-seq analysis revealed that the gene expression patterns were similar in different concentration groups. However, the medium dose group may be able to regulate skin inflammation by regulating upstream genes to inhibit autophagy-related pathways. Further GO analysis revealed that the low-dose group mainly affected metabolism-related genes, the medium-dose group affected more genes related to body systems, and the high-dose group was dominated by genes related to human diseases.

Activation of mouse skin mast cells and cutaneous afferent C-fiber subtypes by bee venom

In mammals, many Hymenopteran stings are characterized by pain, redness, and swelling − three manifestations consistent with nociceptive nerve fiber activation. The effect of a Western honeybee (Apis mellifera) venom on the activation of sensory C-fibers in mouse skin was studied using an innervated isolated mouse skin preparation that allows for intra-arterial delivery of chemicals to the nerve terminals in the skin. Our data show that honeybee venom stimulated mouse cutaneous nociceptive-like C-fibers, with an intensity (action potential discharge frequency) similar to that seen with a maximally-effective concentration of capsaicin. The venom had a stronger effect on chloroquine-sensitive C-fibers compared to chloroquine-insensitive C-fibers, an effect that was recapitulated with a wasp (Vespula spp.) venom. Blocking TRPV1 and TRPA1 channels did not influence the honeybee venom-induced C-fiber activation. The effect of the venoms on chloroquine-sensitive and −insensitive subpopulation of C-fiber terminals was mimicked by melittin but not apamin; two of peptide venom components. Chloroquine-sensitive C-fibers are stimulated as a consequence of mast cell activation. Melittin degranulated mast cells in mouse skin by a non-IgE and non-MrgprB2 mechanism, and this may explain the stronger activation of the chloroquine-sensitive C-fibers.

Oral vancomycin induced flushing syndrome in a multiple myeloma patient: A case report and review of the literature

Background: Patients with hematological malignancies are at high-risk of Clostridium difficile infection (CDI). Oral vancomycin is a first-line treatment for CDI. Vancomycin has been widely reported to induce flushing syndrome (also known as Red man syndrome), a well-known hypersensitivity reaction mostly occurs after intravenous administration. However, a few cases of flushing syndrome due to oral vancomycin have been reported. Methods: We reported a case of the 68-year-old male with Multiple Myeloma contracted suspected CDI during chemotherapy, oral vancomycin (125 mg po q6h) was initiated for CDI. Approximately 24 hours after receiving oral vancomycin, the patient developed vancomycin flushing syndrome with facial flushing and an erythematous rash on the abdomen and back, despite normal vancomycin duration and renal function (no obvious risk factors). Results: The patient was diagnosed with Oral vancomycin induced flushing syndrome. The symptoms resolved after withdrawal of vancomycin and 4 days of treatment with loratadine. Conclusion: Oral vancomycin-induced flushing syndrome is a rare complication that can occur in patients with CDI despite the absence of obvious risk factors. The underlying mechanism of oral vacomycin-induced flushing syndrome may be direct activation of mast cells following mast cell degranulation and histamine release via the MRGPRX2 receptor. However, this is just speculation and there are insufficient data, particularly in vivo data, to draw any conclusions. For patients with risk factors such as gastrointestinal pathology and renal insufficiency, monitoring of vancomycin serum concentration, mast cell degranulation, histamine release, and MRGPRX2 levels is recommended to avoid vancomycin flushing Syndrome, and vancomycin can still be used under supervision.

Ixochymostatin, a trypsin inhibitor-like (TIL) protein from Ixodes scapularis, inhibits chymase and impairs vascular permeability

Ticks obtain a blood meal by lacerating small blood vessels and ingesting the blood that flows to the feeding site, which triggers various host responses. However, ticks face the challenge of wound healing, a process involving hemostasis, inflammation, cell proliferation and migration, and remodeling, hindering blood acquisition. To overcome these obstacles, tick salivary glands produce an array of bioactive molecules. Here, we characterize ixochymostatin, an Ixodes scapularis protein belonging to the trypsin inhibitor-like (TIL) family. It is expressed in multiple developmental stages and in tick salivary glands and acts as a slow and tight-binding inhibitor of chymase, cathepsin G, and chymotrypsin. Predictions for the tertiary structure complex between ixochymostatin and chymase suggest a direct interaction between the inhibitor reactive site loop and protease active sites. In vitro, ixochymostatin protects the endothelial cell barrier against chymase degrading action, decreasing cell permeability. In vivo, it reduces vascular permeability induced by chymase and compound 48/80, a mast cell degranulator agonist, in a mouse model. Additionally, ixochymostatin inhibits the chymase-dependent generation of vasoconstrictor peptides. Antibodies against ixochymostatin neutralize its inhibitory properties, with epitope mapping identifying potential neutralization regions. Ixochymostatin emerges as a novel tick protein modulating host responses against tick feeding, facilitating blood acquisition.

Neuronal substance P-driven MRGPRX2-dependent mast cell degranulation products differentially promote vascular permeability

Neuronal substance P-driven MRGPRX2-dependent mast cell degranulation products differentially promote vascular permeability

Protective effect of Curcuma longa L. leaves and pseudostems extract against 1-chloro-2,4-dinitrobenzene-induced atopic dermatitis in BALB/c mice

Ethnopharmacological relevanceThe perennial herbaceous plant, Curcuma longa L. (turmeric) is primarily grown and harvested for pharmacological purposes in China, Korea, and various tropical regions in South Asia. Turmeric has been used for centuries as an indigenous medicine. In particular, Ayurveda has been extensively used to treat, prevent, and manage multiple illnesses, including inflammation, allergies, arthritis, cancer, diabetes, diarrhea, psoriasis, and digestive issues. Importantly, various studies have confirmed the presence of numerous active compounds with health-enhancing biological properties in turmeric leaves and pseudostems. Aim of the studyAtopic dermatitis (AD) is a long-lasting inflammatory disorder that is associated with abnormalities in the immune system, such as T-helper (Th) cell dysregulation, elevated immunoglobulin (Ig) levels, inflammatory cell infiltration, and skin barrier damage. This study aimed to explore the therapeutic effects of turmeric leaves and pseudostems (CLHW) extract against AD in a BALB/c mouse disease model established using 1-chloro-2,4-dinitrobenzene (DNCB). Materials and methodsAD-like symptoms were induced by topically applying DNCB to the dorsal skin of the mice, which were monitored over five weeks. Fourteen days after induction, the mice were randomly divided into different groups, and the treatment groups received daily oral gavage of CLHW for three weeks. Throughout the monitoring period, we assessed AD-like symptoms, including skin severity score, transepidermal water loss (TEWL), and scratching behavior of the mice. After measuring the body weight and ear thickness, the mice were euthanized. Furthermore, serum Ig and cytokine production levels were measured. Finally, the degrees of spleen and lymph node enlargement were evaluated, and the tissues were used for histopathological and molecular analyses. ResultsCLHW improved AD-like symptoms, including skin severity score, TEWL, scratching frequency, and ear thickness in DNCB-induced AD mice. Additionally, serum levels of IgE, IgG1, and IgG2a, along with various inflammatory cytokines (interleukin [IL]-4, IL-5, and IL-13) and chemokines (Eotaxin and RANTES), were significantly reduced in CLHW-treated mice. CLHW decreased inflammatory cell infiltration and mast cell degranulation while downregulating mRNA expression levels of AD-related innate cytokines (thymic stromal lymphopoietin [TSLP], IL-25, IL-33), inflammatory cytokines (IL-4, IL-10, IL-13), and chemokines (thymus and activation-regulated chemokine [TARC], macrophage-derived chemokine [MDC]) in the dorsal skin. Furthermore, CLHW reduced spleen and lymph node enlargement and downregulated mRNA expression levels of inflammatory cytokines in these tissues in a dose-dependent manner. ConclusionThe results demonstrated that CLHW can effectively suppress DNCB-induced AD-like symptoms by reducing the skin severity score, TEWL, scratching, ear thickness, serum Ig levels, inflammatory cell infiltration, and degranulation of mast cells, as well as the enlargement of the spleen and lymph nodes. Our findings highlight the ethnopharmacological potential of CLHW for treating abnormal immune responses associated with AD.

Effect of acupuncture combined with bloodletting therapy on mast cell degranulation in urticaria rats

To observe the effects of acupuncture combined with bloodletting on the expression of inflammatory factors in serum, the morphology of sensitized skin tissue and the mast cell degranulation in urticaria rats, and to explore the potential mechanism of this therapy for urticaria. Among 42 SD rats of SPF grade, 6 rats were randomly collected for the preparation of sensitized antiserum; and the rest 36 rats were randomized into a blank group, a model group, a positive drug group, an acupuncture group, a bloodletting group and a combined treatment group (acupuncture + bloodletting), 6 rats in each one. The rat model of urticaria was established by passive cutaneous anaphylaxis. In the positive drug group, loratadine (1 mg•kg-1) by gavage was administered once a day. In the acupuncture group, 1 h after gavage with 0.9% NaCl (1 mL), acupuncture was delivered at "Baihui" (GV 20), "Zhongwan" (CV 12), and bilateral "Quchi" (LI 11) and "Xuehai" (SP 10) for 15 min, once daily . In the bloodletting group, 1 h after gavage with 0.9% NaCl (1 mL), bloodletting was operated at "Dazhui" (GV 14) and bilateral "Geshu" (BL 17), around 0.1 mL of bleeding volume at each point, once daily. In the combined treatment group, 1 h after gavage with 0.9% NaCl (1 mL), the interventions as the acupuncture group and the bloodletting group were adopted, once daily. All the interventions started on day 6 of modeling, lasting 2 weeks. After intervention completion, antigenic stimulation was performed in the rats of each group. Using ELISA, the levels of serum immunoglobulin E (IgE), tryptase (TPS), interleukin-4 (IL-4), interleukin-5 (IL-5), tumor necrosis factor-α (TNF-α) were detected. The diameter of the blue spots of the sensitized skin on the back was measured with ruler in each rat. The morphology of sensitized skin tissue was observed using HE staining, and the degranulation of mast cells was observed using Toluidine blue staining. Compared with the blank group, in the model group, the levels of serum IgE, TPS, IL-4, IL-5 and TNF-α increased (P<0.01), the diameter of blue spot on the sensitized part of the rat back was larger (P<0.01), the degranulation rate of mast cells was elevated (P<0.01), and there were obvious inflammatory cell infiltration and edema in the dermis of sensitized skin tissue on the rat back. Compared with the model group, the serum levels of IgE, TPS, IL-4, IL-5 and TNF-α were reduced in the positive drug group, the acupuncture group, the bloodletting group and the combined treatment group (P<0.01, P<0.05); skin blue spot diameter was smaller in the positive drug group and the combined treatment group (P<0.05); the degranulation rate of mast cells decreased in the positive drug group, the acupuncture group, the bloodletting group and the combined treatment group (P<0.01); and the dermal edema, inflammatory infiltration were attenuated in the positive drug group, the acupuncture group, the bloodletting group and the combined treatment group. Compared with the acupuncture group and the bloodletting group, the serum levels of IgE, TPS, IL-4, IL-5 and TNF-α, as well as the degranulation rate of mast cells in the sensitized tissue were lower in the positive drug group and the combined treatment group (P<0.05). Acupuncture combined with bloodletting effectively suppress mast cell degranulation in the sensitized skin tissue on the back of urticaria rats, and ameliorate the histopathological morphology. Its effect mechanism may be related to inhibiting the differentiation and proliferation of helper T cells 2 and regulating the humoral immune response.

Role of Platelet-Activating Factor in the Pathogenesis of Chronic Spontaneous Urticaria.

Chronic spontaneous urticaria (CSU) is a debilitating condition characterized by mast cell activation. Platelet-activating factor (PAF) is produced by various immune cells, including mast cells, basophils, lymphocytes, and eosinophils, which play crucial roles in CSU pathogenesis. It induces mast cell degranulation, increases vascular permeability, and promotes the chemotaxis of inflammatory cells. These effects result in the release of inflammatory mediators, the development of edema, and the persistence of inflammation, which are key features of CSU. Notably, elevated PAF levels have been linked to heightened disease activity and resistance to antihistamine treatment in CSU patients. Despite these findings, the precise role of PAF in CSU pathogenesis remains unclear. Rupatadine, an antihistamine, and heat shock protein 10, a natural anti-inflammatory peptide that selectively inhibits PAF-induced mast cell degranulation, have demonstrated anti-PAF activity. Furthermore, with the molecular structure of the PAF receptor now identified, several experimental PAF receptor antagonists have been synthesized. However, there remains a significant need for the development of therapeutic options targeting PAF in CSU management.

Role of Mast Cell in Hyperalgesic Priming and the Preventive Effect of Electroacupuncture on the Transition from Acute to Chronic Pain

Objective: Injury can lead to long-term changes that increase the sensitivity of afferent nerve endings to subsequent stimulation and pain can transition from acute to chronic. This phenomenon is known as hyperalgesic priming (HP). This study aimed to understand the mechanisms underlying the effect of Electroacupuncture (EA) on HP and optimize acupoint selection for EA to prevent pain transition. Methods: A rat HP model was established using sequential intraplantar injections of carrageenan (Cg) and prostaglandin E2 (PGE2). The pain thresholds were measured using von Frey filaments. EA on bilateral Zusanli(ST36) and Kunlun(BL60) was used to prevent pain transition. The number of mast cells in the ipsilateral hindpaw skin was determined using toluidine blue or fluorescence-labeled avidin staining. The protein expression levels of protein kinase C (PKCε) in the lumbar dorsal root ganglions (DRGs) were detected by western blotting 24 h after PGE2 injection. Serial pharmacological experiments were conducted to evaluate the relationship between mast cells and pain transition. Finally, EA on the bilateral ST36 and Chongyang(ST42) or a novel combination (ST36 and ST42 on the ipsilateral side, and ST36 and BL60 on the contralateral side) was used to prevent pain transition. Results: Although EA applied to ST36 and BL60 alleviated acute pain induced by Cg injection, it failed to prevent the pain transition caused by PGE2 injection. Mast cell accumulation in the ipsilateral hind paw was observed 7 days after Cg injection. Furthermore, mast cell degranulation may be responsible for PKCε activation in the DRG, a marker of pain transition. EA significantly decreased the number of mast cells in the skin of the ipsilateral hind paw when applied at ST36 and ST42, but not when applied at ST36 and BL60. Furthermore, EA employed to ST36 and ST42 significantly reversed long-term hyperalgesia induced by PGE2 injection, even when administered before injection. However, EA did not alleviate acute pain caused by Cg injection. By using a novel acupoint combination, EA simultaneously alleviated acute pain and prevented pain transition. Conclusions: Our study suggests that mast cells play a critical role in both HP and the transition from acute to chronic pain, whereas EA can prevent pain transition by decreasing the number of mast cells in the local tissue. Graphical abstract: http://links.lww.com/AHM/A144.

Antimicrobial Peptide Pro10-1D Exhibits Anti-Allergic Activity: A Promising Therapeutic Candidate.

Although antimicrobial peptides (AMPs) exhibit a range of biological functions, reports on AMPs with therapeutic effects in allergic disorders are limited. In this study, we investigated the anti-allergic effects of Pro10-1D, a 10-meric AMP derived from insect defensin protaetiamycine. Our findings demonstrate that Pro10-1D effectively inhibits antigen-induced degranulation of mast cells (MCs) with IC50 values of approximately 11.6 μM for RBL-2H3 cells and 2.7 μM for bone marrow-derived MCs. Furthermore, Pro10-1D suppressed the secretion of cytokines with IC50 values of approximately 2.8 μM for IL-4 and approximately 8.6 μM for TNF-α. Mechanistically, Pro10-1D inhibited the Syk-LAT-PLCγ1 signaling pathway in MCs and decreased the activation of mitogen-activated protein kinases (MAPKs). Pro10-1D demonstrated a dose-dependent reduction in IgE-mediated passive cutaneous anaphylaxis in mice with an ED50 value of approximately 7.6 mg/kg. Further investigation revealed that Pro10-1D significantly reduced the activity of key kinases Fyn and Lyn, which are critical in the initial phase of the FcεRI-mediated signaling pathway, with IC50 values of approximately 22.6 μM for Fyn and approximately 1.5 μM for Lyn. Collectively, these findings suggest that Pro10-1D represents a novel therapeutic candidate for the treatment of IgE-mediated allergic disorders by targeting the Lyn/Fyn Src family kinases in MCs.

Allergic angina syndrome, allergic myocardial infarct or Kounis syndrome: insights on epidemiology, etiology, diagnosis and treatment. A case report by gadolinium anaphylaxis.

Kounis syndrome (KS) was first described in 1991 by Kounis and Zavras and is also known as allergic angina syndrome or allergy myocardial infarction. It is a rare, and frequently undiagnosed syndrome that is characterized by an anaphylactic reaction. Allergens cause massive degranulation of mast cells leading to coronary spasm, microvascular angina, and/or endothelial dysfunction with myocardial infarction. The annual incidence of severe, life-threatening anaphylaxis with circulatory symptoms is about 7.9-9.6 cases per 100,000 people. More than 300 cases of KS have been described after exposure to various agents such as drugs, insect venoms, food, or medicated stents. Although the incidence of KS is very low, the incidence of myocardial infarction due to anaphylaxis secondary to gadolinium is even lower, reported in a range of 0.002-0.01%. The objective of this article is to review the current data on KS, regarding a case of allergy to gadolinium, which has an extremely low incidence.

The association of dextran sodium sulfate to the bioactive agent I-modulia® attenuates Staphylococcus aureus virulence expression and δ-toxin production

As a part of the human skin commensal bacterial community, Staphylococcus aureus contributes to the host's immune system education. Nevertheless, it is also considered as an opportunistic pathogen involved in cutaneous infections or skin pathologies, in particular atopic dermatitis. To switch to a pathogenic behavior, S. aureus uses regulatory mechanisms to collectively produce virulence factors. Deprivation of these factors has emerged as a promising way to prevent or treat Staphylococcal diseases in facilitating the role of the immune system, while preserving the protective one of the commensal communities. This study focuses on the anti-virulent effect of dextran sodium sulfate (DSS) and I-modulia®, two natural products that have already proven their value in skincare. The anti-virulent capacity of DSS was first demonstrated by a dose-dependent inhibition of δ-toxin release, a virulence factor known to be a potent inducer of mast cell degranulation, on in vitro S. aureus cultures at high and low virulent states. A transcriptomic study was then implemented for a comprehensive overview of the anti-virulent impact. The results have shown the downregulation of many transcripts related to host immune evasion (scn, sbi), as well as exotoxins (α,γ-toxin) and adhesins production (map, emp), mostly under the control of SaeRS Two-Component System (TCS), one of the two major virulence regulators in S. aureus. Interestingly, genes related to secretion systems and the synthesis of exo-proteases were significantly downregulated when DSS was used in combination with I-modulia®. The repression of these genes was not previously observed and reflects a broader inhibitory action. We have also demonstrated that the inhibition of virulence factors didn't affect S. aureus viability. Our findings suggest that combining DSS and I-modulia® could be a promising therapeutic strategy to counteract microbial dysbiosis in the treatment of S. aureus skin pathologies in re-empowering the host's natural immune defenses.

Topiramate Inhibits Capsaicin-Induced Mast Cell Degranulation and CGRP Release in Rat Dura Mater.

Migraine is a disease that stands out for its high prevalence and socioeconomic costs. It involves the entire trigeminovascular system, the signaling substances, and their targets. However, the role of meningeal mast cells in migraine is still unclear. To better understand one of the components of neurogenic inflammation underlying migraine pathophysiology, we developed an in vivo rat model in which the dura mater was exposed bilaterally to investigate the influence of topiramate on capsaicin-induced mast cell degranulation and CGRP release from dura mater. On the day of the experiment, rats were anesthetized, and a craniectomy was performed on each parietal bone. Test substances were applied in situ over the dura mater using the right and left sides of the dura mater for the test and control, respectively. After exposure, the dura mater was processed for mast cell staining and counting. Using this setup, the effect of capsaicin (10-3 M) was evaluated in rats of both sexes, and subsequently the effect of in situ (10-3 M, 20 µL) and (20 mg/kg/day for 10 days) topiramate treatment on mast cell degranulation and CGRP release were evaluated. In both female and male rats, there was a greater amount of degranulated mast cells in the side stimulated by capsaicin compared to the control side in both females (18 ± 3% vs. 74 ± 3%; p = 0.016) and males (28 ± 2% vs. 74 ± 3%, p = 0.016). In the group treated with topiramate for 10 days prior to the experiments, capsaicin did not induce mast cell degranulation (control 20 ± 1% vs. capsaicin 22 ± 1%, p = 0.375) in contrast to animals treated for 10 days with gavage control (control 25 ± 1% vs. capsaicin 76 ± 1%, p = 0.016). Topiramate applied in situ concomitant with capsaicin did not protect the mast cells from degranulation in response to capsaicin (38 ± 2% vs. 44 ± 1%, p = 0.016). There was a significant reduction in CGRP release from the dura mater in the group treated with topiramate for 10 days compared to the control. This study demonstrates a novel experimental model wherein systemic administration of topiramate is observed to modulate the impact of capsaicin on meningeal mast cell degranulation.

Antidepressant-like Effects of Cannabis sativa L. Extract in an Lipopolysaccharide Model: Modulation of Mast Cell Activation in Deep Cervical Lymph Nodes and Dura Mater.

Lipopolysaccharide (LPS)-induced neuroinflammation is a well-established model for studying depression-like behavior, driven by pro-inflammatory cytokines such as TNF-α and IL-1β. Mast cells (MCs) contribute to neuroinflammation by releasing mediators that exacerbate depressive-like symptoms. This study evaluates the antidepressant-like and anti-inflammatory effects of Cannabis sativa L. inflorescence extract (CSL) in an LPS-induced neuroinflammation model. Male C57BL/6 mice were intraperitoneally injected with CSL at doses of 10, 20, and 30 mg/kg, 30 min prior to LPS (0.83 mg/kg) administration. Depressive behaviors were assessed using the sucrose preference test (SPT), tail suspension test (TST), and forced swimming test (FST). The neutrophil-to-lymphocyte ratio (NLR) was measured to assess systemic inflammation. Cytokine levels in the prefrontal cortex (PFC) were measured, and mast cell degranulation in the lymph nodes and dura mater was analyzed histologically (approval number: WKU24-64). CSL significantly improved depressive-like behaviors and decreased the NLR, indicating reduced systemic inflammation. CSL also significantly reduced TNF-α and IL-1β levels in the PFC. Furthermore, CSL inhibited MC degranulation in the deep cervical lymph nodes and dura mater, with the strongest effects observed at 30 mg/kg. CSL demonstrated antidepressant-like and anti-inflammatory effects in an LPS-induced neuroinflammation model, likely through the modulation of cytokine expression and mast cell activity. These results suggest the potential of CSL as a therapeutic option for treating inflammation-related depression.

Gastrointestinal symptoms in children with mastocytosis

Introduction. Mastocytosis is a heterogeneous group of diseases characterized by the abnormal accumulation of clonal mast cells (MCs) in various tissues and organs, including skin, bone marrow, liver, spleen and lymph nodes. The clinical picture of cutaneous and indolent systemic mastocytosis is formed by a wide range of symptoms associated with activation of mast cells. Single European studies have demonstrated wide variability in the frequency of gastrointestinal symptoms (GI-symptoms)) in children with mastocytosis (from 15 to 50%).Aim. To analyze the frequency of mediator-related GI-symptoms in children with different subtypes and clinical forms of mastocytosis.Materials and methods. A prospective observational study included data from 289 children aged 3 to 17 years who were under observation at the Moscow Scientific and Practical Center of Dermatovenereology and Cosmetology. Symptoms were assessed using the Pediatric grade scale of symptoms of mastocytosis. Clinical manifestations of reactions caused by mast cell degranulation were compared with data from clinical and laboratory studies. The concentrations of tryptase and histamine in the blood serum of patients were determined. The incidence of organomegaly and mesenteric lymphadenitis in children with mediating symptoms and without symptoms was determined using ultrasound.Results. 67 (23.2%) patients had GI symptoms. More than half of the patients (51.6%) indicated abdominal pain, 32.3% reported diarrhea. The severity of pain symptoms correlated with the level of serum tryptase (ρ = 0.564, p &lt; 0.01). The incidence of hepatomegaly and mesadenitis in children with GI- symptoms was 19.4% and 25.4%, respectively. In a comparative analysis in groups of children with and without GI symptoms, the differences in the number of identified cases of organomegaly and mesadenitis were statistically significant (p &lt; 0.001). An increase in histamine levels in the blood was detected in half of the patients with complaints of heartburn and nausea.Conclusion. Our results demonstrated that a study of the level of serum tryptase, ultrasound of the abdominal organs and lymph nodes should be carried out in all children with mediator-related GI-symptoms regardless of the clinical form of mastocytosis.