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Project description:Anaphylaxis is a life-threatening complication of allergen exposure. While mechanisms governing anaphylaxis after intravenous injection have been defined in mice, these models neglect mucosal exposure that accompanies food ingestion. We investigated the role of mast cell populations within the intestine of mice in response to antigens delivered orally. Oral anaphylaxis required IgE-FcεR1 signaling, and profiling of intestinal mast cells revealed a rapidly developing population shaped by epithelial cues. Intestinal mast cells were largely epithelium-resident and displayed divergent transcriptomes and effector functions from connective tissue mast cells found throughout the body. Histamine synthesis was diminished and leukotriene generation enhanced. Mice genetically deficient in cysteinyl leukotriene synthesis, or those treated with aLOX5 antagonist, Zileuton, were protected from oral anaphylaxis whereas that elicited by intravenous injection was unaltered.
2025-08-07 | GSE293904 | GEO
Project description:Anaphylaxis is a life-threatening complication of allergen exposure. While mechanisms governing anaphylaxis after intravenous injection have been defined in mice, these models neglect mucosal exposure that accompanies food ingestion. We investigated the role of mast cell populations within the intestine of mice in response to antigens delivered orally. Oral anaphylaxis required IgE-FcεR1 signaling, and profiling of intestinal mast cells revealed a rapidly developing population shaped by epithelial cues. Intestinal mast cells were largely epithelium-resident and displayed divergent transcriptomes and effector functions from connective tissue mast cells found throughout the body. Histamine synthesis was diminished and leukotriene generation enhanced. Mice genetically deficient in cysteinyl leukotriene synthesis, or those treated with aLOX5 antagonist, Zileuton, were protected from oral anaphylaxis whereas that elicited by intravenous injection was unaltered.
2025-08-07 | GSE293561 | GEO
Project description:Intestinal mast cell-derived leukotrienes mediate the anaphylactic response to ingested antigens
| PRJNA1247394 | ENA
Project description:Intestinal mast cell-derived leukotrienes mediate the anaphylactic response to ingested antigens
| PRJNA1245255 | ENA
Project description:Intestinal mast cell-derived leukotrienes mediate the anaphylactic response to ingested antigens
| PRJNA1247403 | ENA
Project description:Histamine-induced vascular leakage is an integral component of many highly prevalent human diseases, including allergies, asthma and anaphylaxis. Yet, how histamine induces the disruption of the endothelial barrier is not well defined. By using genetically modified animal models, pharmacologic inhibitors and a synthetic biology approach, here we show that the small GTPase RhoA mediates histamine-induced vascular leakage. Histamine causes the rapid formation of focal adherens junctions, disrupting the endothelial barrier by acting on H1R Gαq-coupled receptors, which is blunted in endothelial Gαq/11 KO mice. Interfering with RhoA and ROCK function abolishes endothelial permeability, while phospholipase Cβ plays a limited role. Moreover, endothelial-specific RhoA gene deletion prevents vascular leakage and passive cutaneous anaphylaxis in vivo, and ROCK inhibitors protect from lethal systemic anaphylaxis. This study supports a key role for the RhoA signalling circuitry in vascular permeability, thereby identifying novel pharmacological targets for many human diseases characterized by aberrant vascular leakage.
| S-EPMC4394241 | biostudies-literature
Project description:Nicotinamide adenine dinucleotide (NAD+) acts as a cofactor for multiple biological processes. While previous research has revealed that the NAD+ declines associated with aging contributes to an impairment of immune cells, its role in mast cell function, especially in response to an anaphylactic condition, has remained unexplored. We tested whether the restoration of cellular NAD+ concentration by the supplementation of NAD+ boosting molecules prevented mast cell degranulation and anaphylactic responses. Methods: Bone marrow derived mast cells (BMMCs) and human cord blood derived mast cells were treated with NAD+ precursors nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR), and FcεRI downstream signaling was assessed. Animal models of passive systemic anaphylaxis (PSA) and passive cutaneous anaphylaxis (PCA) were used to investigate the effects of NAD+ precursors in the anaphylactic responses of mice. Results: Treatment of murine BMMCs and human cord blood derived mast cells with NAD+ precursors repressed intracellular signaling downstream of FcεRI, as well as the release of inflammatory cytokines and lipid mediators. The intraperitoneal administration of NMN or NR also markedly attenuated IgE-mediated anaphylactic responses in mouse models of PSA and PCA. These beneficial effects of NAD+ precursors, however, were attenuated in mast cell-specific Sirt6 knockout mice, indicating a Sirt6 dependency for their action. Conclusion: NAD+ precursors may serve as an effective therapeutic strategy that limits mast cell-mediated anaphylactic responses.
| S-EPMC9065190 | biostudies-literature
Project description:Degranulation of basophils and mast cells plays a central role in allergic reactions. Degranulation is a response to cell surface receptor aggregation caused by association of receptors with antibodies bound to multivalent antigens. Tools used in studying this process have included small-molecule divalent antigens, but they suffer from weak signaling apparently due to small aggregate size. We have prepared trivalent antigens that allow formation of larger aggregates and potent responses from mast cells.
| S-EPMC3305801 | biostudies-literature
Project description:BackgroundMast cells (MCs) have been found to play a critical role during development of inflammatory bowel disease (IBD) that characterized by dysregulation of inflammation and impaired intestinal barrier function. However, the function of MCs in IBD remains to be fully elucidated.ResultsIn our study, we used exosomes isolated from human mast cells-1 (HMCs-1) to culture with NCM460, HT-29 or CaCO2 of intestinal epithelial cells (IECs) to investigate the communication between MCs and IECs. We found that MCs-derived exosomes significantly increased intestinal epithelial permeability and destroyed intestinal barrier function, which is attributed to exosome-mediated functional miRNAs were transferred from HMCs-1 into IECs, leading to inhibit tight junction-related proteins expression, including tight junction proteins 1 (TJP1, ZO-1), Occludin (OCLN), Claudin 8 (CLDN8). Microarray and bioinformatic analysis have further revealed that a panel of miRNAs target different tight junction-related proteins. Interestingly, miR-223 is enriched in mast cell-derived exosome, which inhibit CLDN8 expression in IECs, while treatment with miR-223 inhibitor in HT-29 cells significantly reversed the inhibitory effect of HMCs-1-derived exosomes on CLDN 8 expression. Most importantly, enrichment of MCs accumulation in intestinal mucosa of patients with IBD compared with those healthy control.ConclusionsThese results indicated that enrichment of exosomal miR-223 from HMCs-1 inhibited CLDN8 expression, leading to destroy intestinal barrier function. These finding provided a novel insight of MCs as a new target for therapeutic treatment of IBD.
| S-EPMC7092522 | biostudies-literature
Project description:Cardiac surgery, especially when employing cardiopulmonary bypass and deep hypothermic circulatory arrest, is associated with systemic inflammatory responses that significantly affect morbidity and mortality. Intestinal perfusion abnormalities have been implicated in such responses, but the mechanisms linking local injury and systemic inflammation remain unclear. Intestinal mast cells are specialized immune cells that secrete various preformed effectors in response to cellular stress. We hypothesized that mast cells are activated in a microenvironment shaped by intestinal ischemia/reperfusion, and investigated local and systemic consequences.Rat model of deep hypothermic circulatory arrest.University research laboratory.Twelve- to 14-week-old male Sprague-Dawley rats.Rats were anesthetized and cooled to 16°C to 18°C on cardiopulmonary bypass before instituting deep hypothermic circulatory arrest for 45 minutes. Specimens were harvested following rewarming and 2 hours of recovery.Significant intestinal barrier disruption was found, together with macro- and microscopic evidence of ischemia/reperfusion injury in ileum and colon, but not in the lungs or kidneys. Immunofluorescence and toluidine blue staining revealed increased numbers of mast cells and their activation in the gut. In animals pretreated with the mast cell stabilizer, cromolyn sodium, mast cell degranulation was blocked, and intestinal morphology and barrier function were preserved following deep hypothermic circulatory arrest. Furthermore, cromolyn sodium treatment was associated with reduced intestinal neutrophil influx and blunted systemic release of proinflammatory cytokines.Our data provide primary evidence that intestinal ischemia/reperfusion is a leading pathophysiologic process in a rat model of deep hypothermic circulatory arrest, and that intestinal injury, and local and systemic inflammatory responses are critically dependent on mast cell activation. This identifies intestinal mast cells as central players in deep hypothermic circulatory arrest-associated responses, and opens novel therapeutic possibilities for patients undergoing this procedure.
| S-EPMC5756097 | biostudies-literature