scholarly journals Tespa1 negatively regulates FcεRI-mediated signaling and the mast cell–mediated allergic response

2014 ◽  
Vol 211 (13) ◽  
pp. 2635-2649 ◽  
Author(s):  
Di Wang ◽  
Mingzhu Zheng ◽  
Yuanjun Qiu ◽  
Chuansheng Guo ◽  
Jian Ji ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Cell Activation ◽  
Cytokine Production ◽  
Adaptor Protein ◽  
Mast Cell Activation ◽  
Allergic Reactions ◽  
Proinflammatory Cytokine Production ◽  
Increased Sensitivity ◽  
Ige Mediated

Antigen-mediated cross-linking of IgE on mast cells triggers a signaling cascade that results in their degranulation and proinflammatory cytokine production, which are key effectors in allergic reactions. We show that the activation of mast cells is negatively regulated by the newly identified adaptor protein Tespa1. Loss of Tespa1 in mouse mast cells led to hyper-responsiveness to stimulation via FcεRI. Mice lacking Tespa1 also displayed increased sensitivity to IgE-mediated allergic responses. The dysregulated signaling in KO mast cells was associated with increased activation of Grb2-PLC-γ1-SLP-76 signaling within the LAT1 (linker for activation of T cells family, member 1) signalosome versus the LAT2 signalosome. Collectively, these findings show that Tespa1 orchestrates mast cell activation by tuning the balance of LAT1 and LAT2 signalosome assembly.

scholarly journals Transgenic mice expressing the human high-affinity immunoglobulin (Ig) E receptor alpha chain respond to human IgE in mast cell degranulation and in allergic reactions.

1996 ◽  
Vol 183 (1) ◽  
pp. 49-56 ◽  
Author(s):  
W P Fung-Leung ◽  
J De Sousa-Hitzler ◽  
A Ishaque ◽  
L Zhou ◽  
J Pang ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Transgenic Mice ◽  
Cell Activation ◽  
Surface Expression ◽  
Mast Cell Activation ◽  
Cell Surface Expression ◽  
Allergic Reactions ◽  
Alpha Chain ◽  
Ige Mediated

The high-affinity receptor for immunoglobulin (Ig) E (Fc epsilon RI) on mast cells and basophils plays a key role in IgE-mediated allergies. Fc epsilon RI is composed of one alpha, one beta, and two gamma chains, which are all required for cell surface expression of Fc epsilon RI, but only the alpha chain is involved in the binding to IgE. Fc epsilon RI-IgE interaction is highly species specific, and rodent Fc epsilon RI does not bind human IgE. To obtain a "humanized" animal model that responds to human IgE in allergic reactions, transgenic mice expressing the human Fc epsilon RI alpha chain were generated. The human Fc epsilon RI alpha chain gene with a 1.3-kb promoter region as a transgene was found to be sufficient for mast cell-specific transcription. Cell surface expression of the human Fc epsilon RI alpha chain was indicated by the specific binding of human IgE to mast cells from transgenic mice in flow cytometric analyses. Expression of the transgenic Fc epsilon RI on bone marrow-derived mast cells was 4.7 x 10(4)/cell, and the human IgE-binding affinity was Kd = 6.4 nM in receptor-binding studies using 125I-IgE. The transgenic human Fc epsilon RI alpha chain was complexed with the mouse beta and gamma chains in immunoprecipitation studies. Cross-linking of the transgenic Fc epsilon RI with human IgE and antigens led to mast cell activation as indicated by enhanced tyrosine phosphorylation of the Fc epsilon RI beta and gamma chains and other cellular proteins. Mast cell degranulation in transgenic mice could be triggered by human IgE and antigens, as demonstrated by beta-hexosaminidase release in vitro and passive cutaneous anaphylaxis in vivo. The results demonstrate that the human Fc epsilon RI alpha chain alone not only confers the specificity in human IgE binding, but also can reconstitute a functional receptor by coupling with the mouse beta and gamma chains to trigger mast cell activation and degranulation in a whole animal system. These transgenic mice "humanized" in IgE-mediated allergies may be valuable for development of therapeutic agents that target the binding of IgE to its receptor.

scholarly journals Unlocking the Non-IgE-Mediated Pseudo-Allergic Reaction Puzzle with Mas-Related G-Protein Coupled Receptor Member X2 (MRGPRX2)

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1033
Author(s):  
Mukesh Kumar ◽  
Karthi Duraisamy ◽  
Billy Kwok Chong CHOW
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Allergic Reaction ◽  
G Protein ◽  
Cell Activation ◽  
Mast Cell Activation ◽  
Allergic Reactions ◽  
Ige Mediated ◽  
G Protein Coupled

Mas-related G-protein coupled receptor member X2 (MRGPRX2) is a class A GPCR expressed on mast cells. Mast cells are granulated tissue-resident cells known for host cell response, allergic response, and vascular homeostasis. Immunoglobulin E receptor (FcεRI)-mediated mast cell activation is a well-studied and recognized mechanism of allergy and hypersensitivity reactions. However, non-IgE-mediated mast cell activation is less explored and is not well recognized. After decades of uncertainty, MRGPRX2 was discovered as the receptor responsible for non-IgE-mediated mast cells activation. The puzzle of non-IgE-mediated pseudo-allergic reaction is unlocked by MRGPRX2, evidenced by a plethora of reported endogenous and exogenous MRGPRX2 agonists. MRGPRX2 is exclusively expressed on mast cells and exhibits varying affinity for many molecules such as antimicrobial host defense peptides, neuropeptides, and even US Food and Drug Administration-approved drugs. The discovery of MRGPRX2 has changed our understanding of mast cell biology and filled the missing link of the underlying mechanism of drug-induced MC degranulation and pseudo-allergic reactions. These non-canonical characteristics render MRGPRX2 an intriguing player in allergic diseases. In the present article, we reviewed the emerging role of MRGPRX2 as a non-IgE-mediated mechanism of mast cell activation in pseudo-allergic reactions. We have presented an overview of mast cells, their receptors, structural insight into MRGPRX2, MRGPRX2 agonists and antagonists, the crucial role of MRGPRX2 in pseudo-allergic reactions, current challenges, and the future research direction.

scholarly journals Beyond IgE: Alternative Mast Cell Activation Across Different Disease States

2020 ◽  
Vol 21 (4) ◽  
pp. 1498 ◽  
Author(s):  
David O. Lyons ◽  
Nicholas A. Pullen
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Cell Activation ◽  
Autoimmune Disorders ◽  
Receptor Expression ◽  
Mast Cell Activation ◽  
Food Allergies ◽  
Type I ◽  
Disease States ◽  
Ige Mediated

Mast cells are often regarded through the lens of IgE-dependent reactions as a cell specialized only for anti-parasitic and type I hypersensitive responses. However, recently many researchers have begun to appreciate the expansive repertoire of stimuli that mast cells can respond to. After the characterization of the interleukin (IL)-33/suppression of tumorigenicity 2 (ST2) axis of mast cell activation—a pathway that is independent of the adaptive immune system—researchers are revisiting other stimuli to induce mast cell activation and/or subsequent degranulation independent of IgE. This discovery also underscores that mast cells act as important mediators in maintaining body wide homeostasis, especially through barrier defense, and can thus be the source of disease as well. Particularly in the gut, inflammatory bowel diseases (Crohn’s disease, ulcerative colitis, etc.) are characterized with enhanced mast cell activity in the context of autoimmune disease. Mast cells show phenotypic differences based on tissue residency, which could manifest as different receptor expression profiles, allowing for unique mast cell responses (both IgE and non-IgE mediated) across varying tissues as well. This variety in receptor expression suggests mast cells respond differently, such as in the gut where immunosuppressive IL-10 stimulates the development of food allergy or in the lungs where transforming growth factor-β1 (TGF-β1) can enhance mast cell IL-6 production. Such differences in receptor expression illustrate the truly diverse effector capabilities of mast cells, and careful consideration must be given toward the phenotype of mast cells observed in vitro. Given mast cells’ ubiquitous tissue presence and their capability to respond to a broad spectrum of non-IgE stimuli, it is expected that mast cells may also contribute to the progression of autoimmune disorders and other disease states such as metastatic cancer through promoting chronic inflammation in the local tissue microenvironment and ultimately polarizing toward a unique Th17 immune response. Furthermore, these interconnected, atypical activation pathways may crosstalk with IgE-mediated signaling differently across disorders such as parasitism, food allergies, and autoimmune disorders of the gut. In this review, we summarize recent research into familiar and novel pathways of mast cells activation and draw connections to clinical human disease.

scholarly journals Resveratrol inhibits IL-33–mediated mast cell activation by targeting the MK2/3–PI3K/Akt axis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Shotaro Nakajima ◽  
Kayoko Ishimaru ◽  
Anna Kobayashi ◽  
Guannan Yu ◽  
Yuki Nakamura ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Cell Activation ◽  
Cytokine Production ◽  
Allergic Diseases ◽  
Mast Cell Activation ◽  
Akt Pathway ◽  
Mouse Lung ◽  
Mouse Bone Marrow ◽  
Interleukin 33

AbstractInterleukin-33 (IL-33)/ST2–mediated mast cell activation plays important roles in the pathophysiology of allergic diseases. Hence, pharmacologically targeting the IL-33/ST2 pathway in mast cells could help to treat such diseases. We found that resveratrol inhibits IL-33/ST2–mediated mast cell activation. Resveratrol suppressed IL-33–induced IL-6, IL-13, and TNF-α production in mouse bone marrow–derived mast cells (BMMCs), mouse fetal skin–derived mast cells, and human basophils. Resveratrol also attenuated cytokine expression induced by intranasal administration of IL-33 in mouse lung. IL-33–mediated cytokine production in mast cells requires activation of the NF-κB and MAPK p38–MAPK-activated protein kinase-2/3 (MK2/3)–PI3K/Akt pathway, and resveratrol clearly inhibited IL-33–induced activation of the MK2/3–PI3K/Akt pathway, but not the NF-κB pathway, without affecting p38 in BMMCs. Importantly, resveratrol inhibited the kinase activity of MK2, and an MK2/3 inhibitor recapitulated the suppressive effects of resveratrol. Resveratrol and an MK2/3 inhibitor also inhibited IgE-dependent degranulation and cytokine production in BMMCs, concomitant with suppression of the MK2/3–PI3K/Akt pathway. These findings indicate that resveratrol inhibits both IL-33/ST2–mediated and IgE-dependent mast cell activation principally by targeting the MK2/3–PI3K/Akt axis downstream of p38. Thus, resveratrol may have potential for the prevention and treatment of broad ranges of allergic diseases.

scholarly journals Preventative and Therapeutic Effects of Low-dose Ionizing Radiation on the Allergic Response of Rat Basophilic Leukemia Cells

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hae Mi Joo ◽  
Eun Hee Hong ◽  
Seong-Jun Cho ◽  
Seon Young Nam ◽  
Ji Young Kim
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Ionizing Radiation ◽  
Therapeutic Effect ◽  
Cell Activation ◽  
Low Dose ◽  
Mast Cell Activation ◽  
Allergic Reactions ◽  
Antigen Antibody ◽  
Basophilic Leukemia

Abstract The prevalence of allergies has increased over the last four decades. In allergic reactions, mast cells induce a hypersensitive immune response to a substance that is normally harmless. Ionizing radiation has different biological effects depending on the dose and dose rate. In this study, we investigated whether low-dose irradiation before (preventative effect) or after (therapeutic effect) an antigen-antibody reaction has an anti-allergic effect. To test this, we activated rat basophilic leukemia (RBL-2H3) mast cells with anti-2,4-dinitrophenyl IgE (antibody) and 2,4-dinitrophenyl human serum albumin, which served as an antigen. To test for both the potential of a preventative effect and a therapeutic effect, we irradiated mast cells both before and after mast cell activation, and we measured mediator release and signaling pathway activity. Low-dose ionizing radiation suppressed mediator release from RBL-2H3 mast cells activated by the antigen-antibody reaction regardless of when the mast cells were irradiated. These results were due to the suppression of FcεRI expression. Therefore, we suggest that low-dose ionizing radiation has a preventative and therapeutic effect in allergic reactions via the FcεRI-mediated RBL-2H3 mast cell activation system.

scholarly journals Direct Inhibition of the Allergic Effector Response by Raw Cow’s Milk—An Extensive In Vitro Assessment

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1258
Author(s):  
Suzanne Abbring ◽  
Bart R. J. Blokhuis ◽  
Julie L. Miltenburg ◽  
Kiri G. J. Romano Olmedo ◽  
Johan Garssen ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Cell Activation ◽  
Allergic Diseases ◽  
Raw Milk ◽  
Mast Cell Activation ◽  
Cow’S Milk ◽  
Cow's Milk ◽  
Ige Mediated ◽  
Raw Cow’S Milk

The mechanisms underlying the allergy-protective effects of raw cow’s milk are poorly understood. The current focus is mainly on the modulation of T cell responses. In the present study, we investigated whether raw cow’s milk can also directly inhibit mast cells, the key effector cells in IgE-mediated allergic responses. Primary murine bone marrow-derived mast cells (BMMC) and peritoneal mast cells (PMC), were incubated with raw milk, heated raw milk, or shop milk, prior to IgE-mediated activation. The effects on mast cell activation and underlying signaling events were assessed. Raw milk was furthermore fractionated based on molecular size and obtained fractions were tested for their capacity to reduce IgE-mediated mast cell activation. Coincubation of BMMC and PMC with raw milk prior to activation reduced β-hexosaminidase release and IL-6 and IL-13 production, while heated raw milk or shop milk had no effect. The reduced mast cell activation coincided with a reduced intracellular calcium influx. In addition, SYK and ERK phosphorylation levels, both downstream signaling events of the FcεRI, were lower in raw milk-treated BMMC compared to control BMMC, although differences did not reach full significance. Raw milk-treated BMMC furthermore retained membrane-bound IgE expression after allergen stimulation. Raw milk fractionation showed that the heat-sensitive raw milk components responsible for the reduced mast cell activation are likely to have a molecular weight of > 37 kDa. The present study demonstrates that raw cow’s milk can also directly affect mast cell activation. These results extend the current knowledge on mechanisms via which raw cow’s milk prevents allergic diseases, which is crucial for the development of new, microbiologically safe, nutritional strategies to reduce allergic diseases.

scholarly journals Ethanol Extract of Sesamum indicum Linn. Inhibits FcεRI-Mediated Allergic Reaction via Regulation of Lyn/Syk and Fyn Signaling Pathways in Rat Basophilic Leukemic RBL-2H3 Mast Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Hyun Ju Do ◽  
Tae Woo Oh ◽  
Kwang-Il Park
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Signaling Pathways ◽  
Inflammatory Mediators ◽  
Cell Activation ◽  
Immunoglobulin E ◽  
Sesamum Indicum ◽  
Mast Cell Activation ◽  
Allergic Reactions ◽  
Potent Effect

This study is aimed at determining whether Sesamum indicum Linn. beneficially influences FcεRI-mediated allergic reactions in RBL-2H3 mast cells; it is also aimed at further investigating Lyn/Fyn and Syk signaling pathways. To examine the antiallergic effect of Sesamum indicum Linn. extract (SIE), we treated antigen/immunoglobulin E- (IgE-) sensitized mast cells with extracts of various concentrations. We examined the degranulation release and concentrations of inflammatory mediators. Additionally, the expressions of genes involved in the FcεRI and arachidonate signaling pathways were examined. SIE inhibited the degranulation and secretion of inflammatory mediators in antigen/IgE-sensitized mast cells. SIE reduced the expressions of FcεRI signaling-related genes, such as Syk, Lyn, and Fyn, and the phosphorylation of extracellular signal-regulated kinase in antigen/IgE-sensitized mast cells. Additionally, in late allergic responses, SIE reduced PGD2 release and COX-2 and cPLA2 phosphorylation expression in FcεRI-mediated mast cell activation. Lastly, 250–500 mg/kg SIE significantly attenuated the Ag/IgE-induced passive cutaneous anaphylaxis (PCA) reaction in mice. The potent effect of SIE on RBL-2H3 mast cell activation indicates that the extract could potentially be used as a novel inhibitor against allergic reactions.

scholarly journals Phospholipase D2 acts as an essential adaptor protein in the activation of Syk in antigen-stimulated mast cells

Blood ◽  
2006 ◽  
Vol 108 (3) ◽  
pp. 956-964 ◽  
Author(s):  
Jun Ho Lee ◽  
Young Mi Kim ◽  
Nam Wook Kim ◽  
Jie Wan Kim ◽  
Erk Her ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Cell Activation ◽  
Adaptor Protein ◽  
Adaptor Proteins ◽  
Mast Cell Activation ◽  
Critical Event ◽  
Phospholipase D1 ◽  
Key Enzyme

Abstract Mast cells are responsible for IgE-mediated allergic reactions. Phospholipase D1 (PLD1) and PLD2 regulate mast cell activation, but the mechanisms remain unclear. Here we show that PLD2 associates with and promotes activation of Syk, a key enzyme in mast cell activation. Antigen stimulation resulted in increased association and colocalization of Syk with PLD2 on the plasma membrane as indicated by coimmunoprecipitation and confocal microscopy. This association was dependent on tyrosine phosphorylation of Syk but not on PLD2 activity. In vitro, PLD2 interacted via its Phox homology (PX) domain with recombinant Syk to induce phosphorylation and activation of Syk. Furthermore, overexpression of PLD2 or catalytically inactive PLD2K758R enhanced antigen-induced phosphorylations of Syk and its downstream targets, the adaptor proteins LAT and SLP-76, while expression of a PLD2 siRNA blocked these phosphorylations. Apparently, the interaction of PLD2 with Syk is an early critical event in the activation of mast cells.

Spiraeoside inhibits mast cells activation and IgE-mediated allergic responses by suppressing phospholipase C-γ-mediated signaling

2015 ◽  
Vol 93 (3) ◽  
pp. 227-235 ◽  
Author(s):  
Jung Kuk Kim ◽  
Young-Kyo Seo ◽  
Sehoon Park ◽  
Soo-Ah Park ◽  
Seyoung Lim ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Phospholipase C ◽  
Cell Activation ◽  
Mapk Signaling ◽  
Mast Cell Activation ◽  
Tnf Α ◽  
Ige Mediated ◽  
Subsequent Activation

Mast cells are responsible for IgE-mediated allergic responses through the secretion of various inflammatory cytokines and mediators. Therefore, the pharmacological regulation of mast cell activation is an important goal in the development of novel anti-allergic drugs. In this study, we found that spiraeoside (SP) inhibits mast cell activation and allergic responses in vivo. SP dose-dependently inhibited the degranulation induced by IgE-antigen (Ag) stimulation in RBL-2H3 mast cells without cytotoxic effects. At the molecular level, SP reduced the Ag-induced phosphorylation and subsequent activation of phospholipase C-γ2 (PLC-γ2). Moreover, SP inhibited the phosphorylation of spleen tyrosine kinase (Syk), linker for activation of T cells (LAT), and downstream MAPKs, such as ERK1/2, p38, and JNK, eventually attenuating expression of TNF-α and IL-4. Finally, we found that SP significantly inhibited IgE-mediated passive cutaneous anaphylaxis (PCA) in mice. Taken together, our results strongly suggest that SP suppresses IgE-mediated mast cell activation and allergic responses by inhibiting Lyn-induced PLC-γ2/MAPK signaling in mast cells.

scholarly journals The Four Distal Tyrosines Are Required for LAT-dependent Signaling in FcεRI-mediated Mast Cell Activation

2003 ◽  
Vol 198 (5) ◽  
pp. 831-843 ◽  
Author(s):  
Shin-ichiroh Saitoh ◽  
Sandra Odom ◽  
Gregorio Gomez ◽  
Connie L. Sommers ◽  
Howard A. Young ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Mast Cell ◽  
Mast Cells ◽  
Phospholipase C ◽  
Cell Activation ◽  
Genetically Modified ◽  
Adaptor Protein ◽  
Retroviral Vectors ◽  
Mast Cell Activation

The linker for activation of T cells (LAT) is an adaptor protein critical for FcεRI-mediated mast cell activation. LAT is a substrate of the tyrosine kinases activated after TCR and FcεRI engagement. After phosphorylation of the cytosolic domain of LAT, multiple signaling molecules such as phospholipase C–γ1, Grb2, and Gads associate with phosphorylated LAT via their SH2 domains. The essential role of the four distal tyrosines in TCR-mediated signaling and T cell development has been demonstrated by experiments using LAT-deficient cell lines and genetically modified mice. To investigate the role of these four tyrosines of LAT in FcεRI-mediated mast cell activation, bone marrow–derived mast cells from LAT-deficient mice were infected with retroviral vectors designed to express wild-type or mutant LAT. Examination of bone marrow–derived mast cells expressing various tyrosine to phenylalanine mutants in LAT demonstrates a differential requirement for these different binding sites. In these studies, assays of biochemical pathways, degranulation, and cytokine and chemokine release were performed. Finally, the role of these tyrosines was also evaluated in vivo using genetically modified animals. Deletion of all four distal tyrosines, and in particular, loss of the primary phospholipase C–γ-binding tyrosine had a significant effect on antigen-induced histamine release.

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