Autoimmune Mast Cell Activation Test as a Diagnostic Tool in Chronic Spontaneous Urticaria.

Chronic spontaneous urticaria (CSU) is associated with skin mast cell activation, and its triggering mechanisms are not completely elucidated. Evidence suggests an autoimmune component of CSU. Our aim was to assess the usefulness of an autoimmune mast cell activation test (aiMAT) for diagnosing and differentiating CSU into different subtypes. We enrolled 43 patients with active, uncontrolled CSU before starting treatment with omalizumab and 15 controls. Patients were evaluated based on omalizumab response. aiMATs were performed using non-IgE-sensitized (NS) or myeloma IgE-sensitized (S) LAD2 cells, which were then stimulated with CSU/control sera (25 µL and 10 µL). The expression of CD63 was assessed with flow cytometry. CD63 response on NS-LAD2 was significantly increased in CSU patients compared to controls after the stimulation with 25 µL CSU/control sera (p = 0.0007) and with 10 µL CSU/control sera (p = 0.0001). The ROC curve analysis demonstrated an area under the curve (AUC) of 0.82. The cutoff for autoimmune-non-IgE-sensitized-MAT was 40.3% CD63+ LAD2, which resulted in 73.3% sensitivity and 81.4% specificity. CD63 response on S-LAD2 was significantly increased in CSU patients compared to controls after the stimulation with 25 µL CSU/control sera (p = 0.03). The ROC curve analysis demonstrated an AUC of 0.66. The cutoff for the autoimmune-myeloma IgE-sensitized-MAT was 58.4% CD63+ cells, which resulted in 62.8% sensitivity and 66.7% specificity. Overall, 36 out of 43 (84%) patients responded to omalizumab, and 7 (16%) were nonresponders. We found no differences between LAD2 CD63 response and response to omalizumab. In conclusion, aiMAT could represent a new diagnostic tool in CSU. Additional studies are needed to evaluate the potential benefits during omalizumab therapy.

Key Disease-Related Genes and Immune Cell Infiltration Landscape in Inflammatory Bowel Disease: A Bioinformatics Investigation.

Inflammatory Bowel Diseases (IBD), which encompass ulcerative colitis (UC) and Crohn's disease (CD), are characterized by chronic inflammation and tissue damage of the gastrointestinal tract. This study aimed to uncover novel disease-gene signatures, dysregulated pathways, and the immune cell infiltration landscape of inflamed tissues. Eight publicly available transcriptomic datasets, including inflamed and non-inflamed tissues from CD and UC patients were analyzed. Common differentially expressed genes (DEGs) were identified through meta-analysis, revealing 180 DEGs. DEGs were implicated in leukocyte transendothelial migration, PI3K-Akt, chemokine, NOD-like receptors, TNF signaling pathways, and pathways in cancer. Protein-protein interaction network and cluster analysis identified 14 central IBD players, which were validated using eight external datasets. Disease module construction using the NeDRex platform identified nine out of 14 disease-associated genes (CYBB, RAC2, GNAI2, ITGA4, CYBA, NCF4, CPT1A, NCF2, and PCK1). Immune infiltration profile assessment revealed a significantly higher degree of infiltration of neutrophils, activated dendritic cells, plasma cells, mast cells (resting/activated), B cells (memory/naïve), regulatory T cells, and M0 and M1 macrophages in inflamed IBD tissue. Collectively, this study identified the immune infiltration profile and nine disease-associated genes as potential modulators of IBD pathogenesis, offering insights into disease molecular mechanisms, and highlighting potential disease modulators and immune cell dynamics.

Unveiling the immune-modulating power of THz-FEL irradiation.

As terahertz (THz) technology advances, the interaction between THz radiation and the living body, particularly its effects on the immune system, has attracted extensive attention but remains poorly understood. This study firstly elucidated that exposure to 3 THz-FEL radiation markedly suppressed contact hypersensitivity reactions in mice induced by DNFB, as evidenced by a reduction in ear thickness and a discernible recovery in the Th1/Th2 cell balance. 3 THz irradiation led to cellular stress in the irradiated skin locale, increasing the levels of IL-4 and IL-10 and modulating the activity and migration of dendritic cells and mast cells. Furthermore, THz irradiation precipitated a rapid alteration in the skin lipidome, altering several categories of bioactive lipids. These findings offer new insights into the immunomodulatory effects of THz radiation on living organisms and the potential underlying mechanisms, with implications for the development of therapeutic approaches in managing skin allergic diseases.

Protection against DSS-induced colitis in mice through FcεRIα deficiency: the role of altered Lactobacillus.

The role of mast cells (MCs) in ulcerative colitis (UC) development is controversial. FcεRI, the IgE high-affinity receptor, is known to activate MCs. However, its role in UC remains unclear. In our study, Anti-FcεRI showed highly diagnostic value for UC. FcεRIα knockout in mice ameliorated DSS-induced colitis in a gut microbiota-dependent manner. Increased Lactobacillus abundance in FcεRIα deficient mice showed strongly correlation with the remission of colitis. RNA sequencing indicated activation of the NLRP6 inflammasome pathway in FcεRIα knockout mice. Additionally, Lactobacillus plantarum supplementation protected against inflammatory injury and goblet cell loss, with activation of the NLRP6 inflammasome during colitis. Notably, this effect was absent when the strain is unable to produce lactic acid. In summary, colitis was mitigated in FcεRIα deficient mice, which may be attributed to the increased abundance of Lactobacillus. These findings contribute to a better understanding of the relationship between allergic reactions, microbiota, and colitis.

Role and mechanisms of mast cells in brain disorders.

Mast cells serve as crucial effector cells within the innate immune system and are predominantly localized in the skin, airways, gastrointestinal tract, urinary and reproductive tracts, as well as in the brain. Under physiological conditions, brain-resident mast cells secrete a diverse array of neuro-regulatory mediators to actively participate in neuroprotection. Meanwhile, as the primary source of molecules causing brain inflammation, mast cells also function as the "first responders" in brain injury. They interact with neuroglial cells and neurons to facilitate the release of numerous inflammatory mediators, proteases, and reactive oxygen species. This process initiates and amplifies immune-inflammatory responses in the brain, thereby contributing to the regulation of neuroinflammation and blood-brain barrier permeability. This article provides a comprehensive overview of the potential mechanisms through which mast cells in the brain may modulate neuroprotection and their pathological implications in various neurological disorders. It is our contention that the inhibition of mast cell activation in brain disorders could represent a novel avenue for therapeutic breakthroughs.

Emerging trends and research hotspots in the relationship between mast cells and atopic dermatitis based on the literature from 2001 to 2024: A bibliometric and visualized analysis.

BACKGROUND: Atopic dermatitis (AD) is a prevalent chronic inflammatory and highly pruritic skin condition characterized by the infiltration of immune cells, notably eosinophils and mast cells. Mast cells (MCs) critically participate in the complex pathogenesis of AD through multiple pathways and have recently garnered growing attention in research. Despite the abundance of related studies published over the years, a comprehensive bibliometric analysis on this topic remains lacking. OBJECTIVE: Our objective was to perform an up-to-date bibliometric analysis of the literature focusing on the relationship between MCs and AD. This analysis would provide valuable insights through a thorough bibliometric review, enabling a clearer understanding of the current research landscape, pinpointing key studies, and detecting emerging trends within this field. METHODS: We searched the Web of Science Core Collection (WoSCC) database on 15 July 2024. The data retrieval strategy was structured as follows: #1: TS = ("mast cells") OR TS = ("mast cell") OR TS = ("mastocyte"); #2: TS = ("atopic dermatitis") OR TS = ("atopic eczema") Final data: (#1 AND #2). A total of 2272 items published between 2001 and 2024 were included. Several scientometric visualization tools, including VOSviewer, R-bibliometrix, CiteSpace and an online analytical platform, were utilized to conduct text mining and to visualize the bibliometric data, facilitating a comprehensive analysis of research trends and patterns. RESULTS: Out of the initial 2272 articles retrieved, 2168 were selected for analysis after applying inclusion and exclusion criteria based on publication type. The findings indicate a steady and substantial exponential growth in the annual number of publications focused on the relationship between over the years. The South Korea (547/2168), USA (465/2168) and Japan (436/2168) were the major contributors within this field, collectively constituting more than half of the total publications. To clarify the underlying mechanisms and role of MCs in the pathogenesis of AD and to make MCs prime targets for therapeutic intervention have garnered the most attention in this field. According to references analysis, the research emphasis has shifted to developing MC-related therapeutics and intervention and regulating the immune system of AD patients through modulating the activity of various immune cells. On the basis of keywords analysis, we outlined the following research frontiers and hotpots in the future: the role of oxidative stress in the pathogenesis; imbalance in the different types of T helper (Th) cells during immune response; skin barrier and barrier dysfunction; improving quality of life; sensory neurons; biological agents and small-molecule drugs. Furthermore, IL-13, IL-4, NFKB1, BCGF-1 and CD4 ranked as the top five genes that have received the most investigative attention in the intersection of MCs and AD. CONCLUSION: In a word, this analysis would greatly benefit from a thorough bibliometric review to gain a deeper understanding of the current research landscape, identify pivotal studies and pinpoint emerging trends in the field of MCs and AD. Meanwhile, our findings offered researchers a holistic perspective of ongoing developments, serving as a valuable resource for guiding future research and informing decision-making for both researchers and policymakers in this area.

Formononetin inhibits IgE by huPlasma/PBMCs and mast cells/basophil activation via JAK/STAT/PI3-Akt pathways.

Rationale: Food allergy is a prevalent disease in the U.S., affecting nearly 30 million people. The primary management strategy for this condition is food avoidance, as limited treatment options are available. The elevation of pathologic IgE and over-reactive mast cells/basophils is a central factor in food allergy anaphylaxis. This study aims to comprehensively evaluate the potential therapeutic mechanisms of a small molecule compound called formononetin in regulating IgE and mast cell activation. Methods: In this study, we determined the inhibitory effect of formononetin on the production of human IgE from peripheral blood mononuclear cells of food-allergic patients using ELISA. We also measured formononetin's effect on preventing mast cell degranulation in RBL-2H3 and KU812 cells using beta-hexosaminidase assay. To identify potential targets of formononetin in IgE-mediated diseases, mast cell disorders, and food allergies, we utilized computational modeling to analyze mechanistic targets of formononetin from various databases, including SEA, Swiss Target Prediction, PubChem, Gene Cards, and Mala Cards. We generated a KEGG pathway, Gene Ontology, and Compound Target Pathway Disease Network using these targets. Finally, we used qRT-PCR to measure the gene expression of selected targets in KU812 and U266 cell lines. Results: Formononetin significantly decreased IgE production in IgE-producing human myeloma cells and PBMCs from food-allergic patients in a dose-dependent manner without cytotoxicity. Formononetin decreased beta-hexosaminidase release in RBL-2H3 cells and KU812 cells. Formononetin regulates 25 targets in food allergy, 51 in IgE diseases, and 19 in mast cell diseases. KEGG pathway and gene ontology analysis of targets showed that formononetin regulated disease pathways, primary immunodeficiency, Epstein-Barr Virus, and pathways in cancer. The biological processes regulated by formononetin include B cell proliferation, differentiation, immune response, and activation processes. Compound target pathway disease network identified NFKB1, NFKBIA, STAT1, STAT3, CCND1, TP53, TYK2, and CASP8 as the top targets regulated at a high degree by formononetin. TP53, STAT3, PTPRC, IL2, and CD19 were identified as the proteins mostly targeted by formononetin. qPCR validated genes of Formononetin molecular targets of IgE regulation in U266 cells and KU812 cells. In U266 cells, formononetin was found to significantly increase the gene expression of NFKBIA, TP53, and BCL-2 while decreasing the gene expression of BTK TYK, CASP8, STAT3, CCND1, STAT1, NFKB1, IL7R. In basophils KU812 cells, formononetin significantly increased the gene expression of NFKBIA, TP53, and BCL-2 while decreasing the gene expression of BTK, TYK, CASP8, STAT3, CCND1, STAT1, NFKB1, IL7R. Conclusion: These findings comprehensively present formononetin's mechanisms in regulating IgE production in plasma cells and degranulation in mast cells.

Dynamin 2-mediated endocytosis of BLT1 is required for IL-8 production in HMC-1 cells induced by Trichomonas vaginalis-derived secretory products.

We previously reported that leukotriene B4 (LTB4) contained in Trichomonas vaginalis-derived secretory products (TvSP) play an essential role in interleukin-8 (IL-8) production in human mast cell line (HMC-1 cells) via LTB4 receptor (BLT)-mediated Nuclear Factor-kappa B (NF-кB) activation. Dynamin, a GTPase, has been known to be involved in endocytosis of receptors for signaling of production of cytokine or chemokines. In the present study, we investigated the role of dynamin-mediated BLT1 endocytosis in TvSP-induced IL-8 production. When HMC-1 cells were transfected with BLT1 or BLT2 siRNA, TvSP-induced IL-8 production was significantly inhibited compared with that in cells transfected with control siRNA. In addition, pretreatment of HMC-1 cells with a dynamin inhibitor (Dynasore) reduced IL-8 production induced by TvSP or LTB4. TvSP- or LTB4- induced phosphorylation of NF-кB was also attenuated by pretreatment with Dynasore. After exposing HMC-1 cells to TvSP or LTB4, BLT1 was translocated from the intracellular compartments to the plasma membrane within 30 min. At 60 min after stimulation with TvSP or LTB4, BLT1 remigrated from the cell surface to intracellular areas. Pretreatment of HMC-1 cells with dynamin-2 siRNA blocked internalization of BLT1 induced by TvSP or LTB4. Co-immunoprecipitation experiments revealed that dynamin-2 strongly interacted with BLT1 60 min after stimulation with TvSP or LTB4. These results suggest that T. vaginalis-secreted LTB4 induces IL-8 production in HMC-1 cells via dynamin 2-mediated endocytosis of BLT1 and phosphorylation of NF-кB.

CysLT receptor-mediated NOX2 activation is required for IL-8 production in HMC-1 cells induced by Trichomonas vaginalis-derived secretory products.

Trichomoniasis is caused by a sexually transmitted flagellate protozoan parasite Trichomonas vaginalis. T. vaginalis-derived secretory products (TvSP) contain lipid mediators such as leukotriene B4 (LTB4) and various cysteinyl leukotrienes (CysLTs) which included LTC4, LTD4, and LTE4. However, the signaling mechanisms by which T. vaginalis-induced CysLTs stimulate interleukin (IL)-8 production in human mast cells remain unclear. In this study, we investigated these mechanisms in human mast cells (HMC-1). Stimulation with TvSP resulted in increased intracellular reactive oxygen species (ROS) generation and NADPH oxidase 2 (NOX2) activation compared to unstimulated cells. Pre-treatment with NOX2 inhibitors such as diphenyleneiodonium chloride (DPI) or apocynin significantly reduced ROS production in TvSP-stimulated HMC-1 cells. Additionally, TvSP stimulation increased NOX2 protein expression and the translocation of p47phox from the cytosol to the membrane. Pretreatment of HMC-1 cells with PI3K or PKC inhibitors reduced TvSP-induced p47phox translocation and ROS generation. Furthermore, NOX2 inhibitors or NOX2 siRNA prevented CREB phosphorylation and IL-8 gene expression or protein secretion induced by TvSP. Pretreatment with a CysLTR antagonist significantly inhibited TvSP-induced ROS production, CREB phosphorylation, and IL-8 production. These results indicate that CysLT-mediated activation of NOX2 plays a crucial role in ROS-dependent IL-8 production in human mast cells stimulated by T. vaginalis-secreted CysLTs. These findings enhance our understanding of the inflammatory response in trichomoniasis and may inform the development of targeted therapies to mitigate this response.

Elucidating the role of tumor-associated ALOX5+ mast cells with transformative function in cervical cancer progression via single-cell RNA sequencing.

Background: Cervical cancer (CC) is the fourth most common malignancy among women globally and serves as the main cause of cancer-related deaths among women in developing countries. The early symptoms of CC are often not apparent, with diagnoses typically made at advanced stages, which lead to poor clinical prognoses. In recent years, numerous studies have shown that there is a close relationship between mast cells (MCs) and tumor development. However, research on the role MCs played in CC is still very limited at that time. Thus, the study conducted a single-cell multi-omics analysis on human CC cells, aiming to explore the mechanisms by which MCs interact with the tumor microenvironment in CC. The goal was to provide a scientific basis for the prevention, diagnosis, and treatment of CC, with the hope of improving patients' prognoses and quality of life. Method: The present study acquired single-cell RNA sequencing data from ten CC tumor samples in the ArrayExpress database. Slingshot and AUCcell were utilized to infer and assess the differentiation trajectory and cell plasticity of MCs subpopulations. Differential expression analysis of MCs subpopulations in CC was performed, employing Gene Ontology, gene set enrichment analysis, and gene set variation analysis. CellChat software package was applied to predict cell communication between MCs subpopulations and CC cells. Cellular functional experiments validated the functionality of TNFRSF12A in HeLa and Caski cell lines. Additionally, a risk scoring model was constructed to evaluate the differences in clinical features, prognosis, immune infiltration, immune checkpoint, and functional enrichment across various risk scores. Copy number variation levels were computed using inference of copy number variations. Result: The obtained 93,524 high-quality cells were classified into ten cell types, including T_NK cells, endothelial cells, fibroblasts, smooth muscle cells, epithelial cells, B cells, plasma cells, MCs, neutrophils, and myeloid cells. Furthermore, a total of 1,392 MCs were subdivided into seven subpopulations: C0 CTSG+ MCs, C1 CALR+ MCs, C2 ALOX5+ MCs, C3 ANXA2+ MCs, C4 MGP+ MCs, C5 IL32+ MCs, and C6 ADGRL4+ MCs. Notably, the C2 subpopulation showed close associations with tumor-related MCs, with Slingshot results indicating that C2 subpopulation resided at the intermediate-to-late stage of differentiation, potentially representing a crucial transition point in the benign-to-malignant transformation of CC. CNVscore and bulk analysis results further confirmed the transforming state of the C2 subpopulation. CellChat analysis revealed TNFRSF12A as a key receptor involved in the actions of C2 ALOX5+ MCs. Moreover, in vitro experiments indicated that downregulating the TNFRSF12A gene may partially inhibit the development of CC. Additionally, a prognosis model and immune infiltration analysis based on the marker genes of the C2 subpopulation provided valuable guidance for patient prognosis and clinical intervention strategies. Conclusions: We first identified the transformative tumor-associated MCs subpopulation C2 ALOX5+ MCs within CC, which was at a critical stage of tumor differentiation and impacted the progression of CC. In vitro experiments confirmed the inhibitory effect of knocking down the TNFRSF12A gene on the development of CC. The prognostic model constructed based on the C2 ALOX5+MCs subset demonstrated excellent predictive value. These findings offer a fresh perspective for clinical decision-making in CC.

Neuroimmune recognition of allergens.

Interactions between the nervous system and the immune system play crucial roles in initiating and directing the type 2 immune response. Sensory neurons can initiate innate and adaptive type 2 immunity through their ability to detect allergens and promote dendritic cell and mast cell responses. Neurons also indirectly promote type 2 inflammation through suppression of type 1 immune responses. Type 2 cytokines promote neuronal function by directly activating or sensitizing neurons. This positive neuroimmune feedback loop may not only enhance allergic inflammation but also promote the system-wide responses of aversion, anaphylaxis, and allergen polysensitization that are characteristic of allergic immunity.

Anti-Allergic and Anti-Inflammatory Signaling Mechanisms of Natural Compounds/Extracts in In Vitro System of RBL-2H3 Cell: A Systematic Review.

Various extracts are tested for anti-allergic or anti-inflammatory properties on in vitro models. RBL-2H3 cells are widely used in allergic or immunological studies. FCεRI and its downstream signaling cascades, such as MAPK, NF-κB, and JAK/STAT signaling pathways, are important allergic or inflammatory signaling mechanisms in mast and basophil cells. This systematic review aims to study common signaling pathways of the anti-allergic or anti-inflammatory compounds on RBL-2H3 cells. We selected the relevant research articles published after 2015 from the PubMed, Scopus, Science Direct and Web of Science databases. The risk of bias of the studies was assessed based on the modified CONSORT checklist for in vitro studies. The cell lines, treatments, assay, primary findings, and signaling pathways on RBL-2H3 cells were extracted to synthesize the results. Thirty-eight articles were included, and FCεRI and its downstream pathways, such as Lyn, Sky, PLCγ, and MAPK, were commonly studied. Moreover, the JAK/STAT pathway was a potential signaling mechanism in RBL-2H3 cells. However, the findings based on RBL-2H3 cells needed to be tested along with human mast cells to confirm its relevance to human health. In conclusion, a single plant extract may act as an anti-inflammatory reagent in RBL-2H3 cells via multiple signaling pathways besides the MAPK signaling pathway.

CD4+CCR5+ T cells and CCL3+ mast cells are increased in the skin of patients with chronic spontaneous urticaria.

Background: The proximity of activated T cells and mast cells in the lesional skin of patients with chronic spontaneous urticaria (CSU) is held to contribute to the development of wheals and angioedema. In a previous study, we demonstrated that increased IL-17 expression in T cells and mast cells in skin lesions of patients with CSU is associated with T/mast cell proximity, but the mechanisms that drive T cell/mast cell co-localization remain unknown. Objectives: To assess if chemokines expressed in lesional CSU skin contribute to T cell/mast cell proximity. Patients and methods: Biopsies from lesional CSU skin were compared to biopsies from healthy skin for expression of CCR5 and its ligand CCL3 by CD4+ T cells and mast cells, respectively. Results: Numbers of CCR5-positive CD4+ T cells in lesional CSU skin were significantly increased as compared to healthy normal skin (p < 0.0001). The number of mast cells expressing CCL3 (ligand for CCR5) in CSU skin was also increased (p < 0.0002) and significant association with T-cell close proximity (p < 0.0001) is noticed. Conclusions: The close proximity of T cells and mast cells in the skin of severe CSU may be driven, at least in part by increased CCR5 and CCL3 expression. Therapies that target CCL3 interaction with CCR5 should be assessed for their effects in CSU.

Modulation of MHC expression by interferon-gamma and its influence on PBMC-mediated cytotoxicity in canine mast cell tumour cells.

Immunotherapy is a promising alternative treatment for canine mast cell tumour (MCT). However, evasion of immune recognition by downregulating major histocompatibility complex (MHC) molecules might decline treatment efficiency. Enhancing MHC expression through interferon-gamma (IFN-γ) is crucial for effective immunotherapy. In-house and reference canine MCT cell lines derived from different tissue origins were used. The impacts of IFN-γ treatment on cell viability, expression levels of MHC molecules, as well as cell apoptosis were evaluated through the MTT assay, RT-qPCR and flow cytometry. The results revealed that IFN-γ treatment significantly influenced the viability of canine MCT cell lines, with varying responses observed among different cell lines. Notably, IFN-γ treatment increased the expression of MHC I and MHC II, potentially enhancing immune recognition and MCT cell clearance. Flow cytometry analysis in PBMCs-mediated cytotoxicity assays showed no significant differences in overall apoptosis between IFN-γ treated and untreated canine MCT cell lines across various target-to-effector ratios. However, a trend towards higher percentages of late and total apoptotic cells was observed in the IFN-γ treated C18 and CMMC cell lines, but not in the VIMC and CoMS cell lines. These results indicate a variable response to IFN-γ treatment among different canine MCT cell lines. In summary, our study suggests IFN-γ's potential therapeutic role in enhancing immune recognition and clearance of MCT cells by upregulating MHC expression and possibly promoting apoptosis, despite variable responses across different cell lines. Further investigations are necessary to elucidate the underlying mechanisms and evaluate IFN-γ's efficacy in in vivo models.

Innate Immune Cells in Melanoma: Implications for Immunotherapy.

The innate immune system, composed of neutrophils, basophils, eosinophils, myeloid-derived suppressor cells (MDSCs), macrophages, dendritic cells (DCs), mast cells (MCs), and innate lymphoid cells (ILCs), is the first line of defense. Growing evidence demonstrates the crucial role of innate immunity in tumor initiation and progression. Several studies support the idea that innate immunity, through the release of pro- and/or anti-inflammatory cytokines and tumor growth factors, plays a significant role in the pathogenesis, progression, and prognosis of cutaneous malignant melanoma (MM). Cutaneous melanoma is the most common skin cancer, with an incidence that rapidly increased in recent decades. Melanoma is a highly immunogenic tumor, due to its high mutational burden. The metastatic form retains a high mortality. The advent of immunotherapy revolutionized the therapeutic approach to this tumor and significantly ameliorated the patients' clinical outcome. In this review, we will recapitulate the multiple roles of innate immune cells in melanoma and the related implications for immunotherapy.

Mast cell stabilizers: from pathogenic roles to targeting therapies.

Mast cells (MCs) are bone-marrow-derived haematopoietic cells that are widely distributed in human tissues. When activated, they will release tryptase, histamine and other mediators that play major roles in a diverse array of diseases/disorders, including allergies, inflammation, cardiovascular diseases, autoimmune diseases, cancers and even death. The multiple pathological effects of MCs have made their stabilizers a research hotspot for the treatment of related diseases. To date, the clinically available MC stabilizers are limited. Considering the rapidly increasing incidence rate and widespread prevalence of MC-related diseases, a comprehensive reference is needed for the clinicians or researchers to identify and choose efficacious MC stabilizers. This review analyzes the mechanism of MC activation, and summarizes the progress made so far in the development of MC stabilizers. MC stabilizers are classified by the action mechanism here, including acting on cell surface receptors, disturbing signal transduction pathways and interfering exocytosis systems. Particular emphasis is placed on the clinical applications and the future development direction of MC stabilizers.

Exploring the role of granzyme B in subretinal fibrosis of age-related macular degeneration.

Age-related macular degeneration (AMD), a prevalent and progressive degenerative disease of the macula, is the leading cause of blindness in elderly individuals in developed countries. The advanced stages include neovascular AMD (nAMD), characterized by choroidal neovascularization (CNV), leading to subretinal fibrosis and permanent vision loss. Despite the efficacy of anti-vascular endothelial growth factor (VEGF) therapy in stabilizing or improving vision in nAMD, the development of subretinal fibrosis following CNV remains a significant concern. In this review, we explore multifaceted aspects of subretinal fibrosis in nAMD, focusing on its clinical manifestations, risk factors, and underlying pathophysiology. We also outline the potential sources of myofibroblast precursors and inflammatory mechanisms underlying their recruitment and transdifferentiation. Special attention is given to the potential role of mast cells in CNV and subretinal fibrosis, with a focus on putative mast cell mediators, tryptase and granzyme B. We summarize our findings on the role of GzmB in CNV and speculate how GzmB may be involved in the pathological transition from CNV to subretinal fibrosis in nAMD. Finally, we discuss the advantages and drawbacks of animal models of subretinal fibrosis and pinpoint potential therapeutic targets for subretinal fibrosis.

Mast Cell Infiltration and Subtype Promote Malignant Transformation of Oral Precancer and Progression of Oral Cancer.

The role of mast cell (MC), a common myeloid-derived immune cell, in the development of oral squamous cell carcinoma (OSCC) is unclear. The aim of this study was to investigate MC infiltration in oral precancer and oral cancer. The evaluation of immune cell infiltration and its association with prognosis in OSCC used RNA sequencing and multiple public datasets. Multiplex immunofluorescence was used to explore the infiltration of MC in the microenvironment of OSCC and oral precancer and the interaction with CD8+ cells. The role of MC in OSCC progression was verified by in vivo experiments. The resting MC infiltration was mainly present in oral precancer, whereas activated MC infiltration was significantly higher in OSCC. Activated MC was associated with malignant transformation of oral precancer and poor prognosis of OSCC. In vivo studies showed that MC promoted the growth of OSCC. The infiltration of activated MC was negatively correlated with the infiltration of CD8+ T cells. The subtype of MC containing tryptase without chymase (MCT) was significantly higher in OSCC compared with oral precancer and was associated with poor survival. Furthermore, spatial distance analysis revealed a greater distance between MCT and CD8+ cells, which was also linked to poor prognosis in OSCC. Cox regression analysis showed that MCT could be a potential diagnostic and prognostic biomarker. This study provides new insights into the role of MC in the immune microenvironment of OSCC. It might enhance the immunotherapeutic efficacy of OSCC by developing targeted therapies against MC. SIGNIFICANCE: In this study, we investigated the role of mast cells (MC) in oral precancer and oral cancer and demonstrated that MCs are involved in oral cancer progression and may serve as a potential diagnostic and prognostic marker. It might improve the immunotherapeutic efficacy through developing targeted therapies against MCs.

The JAK1/JAK2 inhibitor ruxolitinib inhibits mediator release from human basophils and mast cells.

Introduction: The Janus kinase (JAK) family includes four cytoplasmic tyrosine kinases (JAK1, JAK2, JAK3, and TYK2) constitutively bound to several cytokine receptors. JAKs phosphorylate downstream signal transducers and activators of transcription (STAT). JAK-STAT5 pathways play a critical role in basophil and mast cell activation. Previous studies have demonstrated that inhibitors of JAK-STAT pathway blocked the activation of mast cells and basophils. Methods: In this study, we investigated the in vitro effects of ruxolitinib, a JAK1/2 inhibitor, on IgE- and IL-3-mediated release of mediators from human basophils, as well as substance P-induced mediator release from skin mast cells (HSMCs). Results: Ruxolitinib concentration-dependently inhibited IgE-mediated release of preformed (histamine) and de novo synthesized mediators (leukotriene C4) from human basophils. Ruxolitinib also inhibited anti-IgE- and IL-3-mediated cytokine (IL-4 and IL-13) release from basophils, as well as the secretion of preformed mediators (histamine, tryptase, and chymase) from substance P-activated HSMCs. Discussion: These results indicate that ruxolitinib, inhibiting the release of several mediators from human basophils and mast cells, is a potential candidate for the treatment of inflammatory disorders.

Acute and prolonged effects of interleukin-33 on cytokines in human cord blood-derived mast cells.

Mast cells are multifaceted cells localized in tissues and possess various surface receptors that allow them to respond to inner and external threat signals. Interleukin-33 (IL-33) is a cytokine released by structural cells in response to parasitic infections, mechanical damage, and cell death. IL-33 can activate mast cells, causing them to release an array of mediators. This study aimed to identify the different cytokines released by human cord blood-derived mast cells (hCBMCs) in response to acute and prolonged stimulation with IL-33. For this purpose, a hCBMC model was established and stimulated with 10 ng and 20 ng of recombinant human IL-33 (rhIL-33) for 6 h and 24 h. Total RNA was hybridized using a high-density oligonucleotide microarray. A multiplex assay was performed to assess the released cytokines. Acute exposure to rhIL-33 increased the expression of IL-1α, IL-1ß, IL-6, and IL-13, whereas prolonged exposure increased the expression of IL-5 and IL-10, and cytokines were detected in the culture supernatant. WebGestalt analysis revealed that rhIL-33 induces pathways and biological processes related to the immune system and the acute inflammatory response. This study demonstrates that rhIL-33 can activate hCBMCs to release pro- and anti-inflammatory cytokines, eliciting distinct acute and prolonged responses unique to hCBMCs.