scholarly journals Tim-3 enhances FcεRI-proximal signaling to modulate mast cell activation

2015 ◽  
Vol 212 (13) ◽  
pp. 2289-2304 ◽  
Author(s):  
Binh L. Phong ◽  
Lyndsay Avery ◽  
Tina L. Sumpter ◽  
Jacob V. Gorman ◽  
Simon C. Watkins ◽  
...  
Keyword(s):  
T Cells ◽  
Mast Cell ◽  
Signaling Pathways ◽  
Cell Activation ◽  
Molecular Mechanisms ◽  
Late Phase ◽  
Cell Types ◽  
Mast Cell Activation ◽  
Positive Role ◽  
Ample Evidence

T cell (or transmembrane) immunoglobulin and mucin domain protein 3 (Tim-3) has attracted significant attention as a novel immune checkpoint receptor (ICR) on chronically stimulated, often dysfunctional, T cells. Antibodies to Tim-3 can enhance antiviral and antitumor immune responses. Tim-3 is also constitutively expressed by mast cells, NK cells and specific subsets of macrophages and dendritic cells. There is ample evidence for a positive role for Tim-3 in these latter cell types, which is at odds with the model of Tim-3 as an inhibitory molecule on T cells. At this point, little is known about the molecular mechanisms by which Tim-3 regulates the function of T cells or other cell types. We have focused on defining the effects of Tim-3 ligation on mast cell activation, as these cells constitutively express Tim-3 and are activated through an ITAM-containing receptor for IgE (FcεRI), using signaling pathways analogous to those in T cells. Using a variety of gain- and loss-of-function approaches, we find that Tim-3 acts at a receptor-proximal point to enhance Lyn kinase-dependent signaling pathways that modulate both immediate-phase degranulation and late-phase cytokine production downstream of FcεRI ligation.

scholarly journals Molecular Mechanisms of Mast Cell Activation by Cholesterol-Dependent Cytolysins

2021 ◽  
Vol 12 ◽  
Author(s):  
Lubica Draberova ◽  
Magda Tumova ◽  
Petr Draber
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Signaling Pathways ◽  
Inflammatory Mediators ◽  
Pore Formation ◽  
Cell Activation ◽  
Molecular Mechanisms ◽  
Biologically Active ◽  
Mast Cell Activation ◽  
Concentration Changes

Mast cells are potent immune sensors of the tissue microenvironment. Within seconds of activation, they release various preformed biologically active products and initiate the process of de novo synthesis of cytokines, chemokines, and other inflammatory mediators. This process is regulated at multiple levels. Besides the extensively studied IgE and IgG receptors, toll-like receptors, MRGPR, and other protein receptor signaling pathways, there is a critical activation pathway based on cholesterol-dependent, pore-forming cytolytic exotoxins produced by Gram-positive bacterial pathogens. This pathway is initiated by binding the exotoxins to the cholesterol-rich membrane, followed by their dimerization, multimerization, pre-pore formation, and pore formation. At low sublytic concentrations, the exotoxins induce mast cell activation, including degranulation, intracellular calcium concentration changes, and transcriptional activation, resulting in production of cytokines and other inflammatory mediators. Higher toxin concentrations lead to cell death. Similar activation events are observed when mast cells are exposed to sublytic concentrations of saponins or some other compounds interfering with the membrane integrity. We review the molecular mechanisms of mast cell activation by pore-forming bacterial exotoxins, and other compounds inducing cholesterol-dependent plasma membrane perturbations. We discuss the importance of these signaling pathways in innate and acquired immunity.

scholarly journals Mast cell activation is enhanced by Tim1:Tim4 interaction but not by Tim-1 antibodies

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 251
Author(s):  
Binh Phong ◽  
Lawrence P. Kane
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Signaling Pathways ◽  
Cell Activation ◽  
Molecular Mechanisms ◽  
Cell Function ◽  
Immune Cell ◽  
Allergic Diseases ◽  
Mast Cell Activation ◽  
High Affinity Ige Receptor

Polymorphisms in theT cell (or transmembrane) immunoglobulin and mucin domain 1(TIM-1) gene, particularly in the mucin domain, have been associated with atopy and allergic diseases in mice and human. Genetic- and antibody-mediated studies revealed that Tim-1 functions as a positive regulator of Th2 responses, while certain antibodies to Tim-1 can exacerbate or reduce allergic lung inflammation. Tim-1 can also positively regulate the function of B cells, NKT cells, dendritic cells and mast cells. However, the precise molecular mechanisms by which Tim-1 modulates immune cell function are currently unknown. In this study, we have focused on defining Tim-1-mediated signaling pathways that enhance mast cell activation through the high affinity IgE receptor (FceRI). Using a Tim-1 mouse model lacking the mucin domain (Tim-1Dmucin), we show for the first time that the polymorphic Tim-1 mucin region is dispensable for normal mast cell activation. We further show that Tim-4 cross-linking of Tim-1 enhances select signaling pathways downstream of FceRI in mast cells, including mTOR-dependent signaling, leading to increased cytokine production but without affecting degranulation.

scholarly journals Mast cell activation is enhanced by Tim1:Tim4 interaction but not by Tim-1 antibodies

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 251
Author(s):  
Binh Phong ◽  
Lawrence P. Kane
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Signaling Pathways ◽  
Cell Activation ◽  
Molecular Mechanisms ◽  
Cell Function ◽  
Immune Cell ◽  
Allergic Diseases ◽  
Mast Cell Activation ◽  
High Affinity Ige Receptor

Polymorphisms in theT cell (or transmembrane) immunoglobulin and mucin domain 1(TIM-1) gene, particularly in the mucin domain, have been associated with atopy and allergic diseases in mice and human. Genetic- and antibody-mediated studies revealed that Tim-1 functions as a positive regulator of Th2 responses, while certain antibodies to Tim-1 can exacerbate or reduce allergic lung inflammation. Tim-1 can also positively regulate the function of B cells, NKT cells, dendritic cells and mast cells. However, the precise molecular mechanisms by which Tim-1 modulates immune cell function are currently unknown. In this study, we have focused on defining Tim-1-mediated signaling pathways that enhance mast cell activation through the high affinity IgE receptor (FceRI). Using a Tim-1 mouse model lacking the mucin domain (Tim-1Dmucin), we show for the first time that the polymorphic Tim-1 mucin region is dispensable for normal mast cell activation. We further show that Tim-4 cross-linking of Tim-1 enhances select signaling pathways downstream of FceRI in mast cells, including mTOR-dependent signaling, leading to increased cytokine production but without affecting degranulation.

scholarly journals Foxp3+ Regulatory T Cells Delay Expulsion of Intestinal Nematodes by Suppression of IL-9-Driven Mast Cell Activation in BALB/c but Not in C57BL/6 Mice

2014 ◽  
Vol 10 (2) ◽  
pp. e1003913 ◽  
Author(s):  
Birte Blankenhaus ◽  
Martina Reitz ◽  
Yannick Brenz ◽  
Marie-Luise Eschbach ◽  
Wiebke Hartmann ◽  
...  
Keyword(s):  
T Cells ◽  
Mast Cell ◽  
Regulatory T Cells ◽  
Cell Activation ◽  
Mast Cell Activation

scholarly journals Granzyme D Is a Novel Murine Mast Cell Protease That Is Highly Induced by Multiple Pathways of Mast Cell Activation

2013 ◽  
Vol 81 (6) ◽  
pp. 2085-2094 ◽  
Author(s):  
Elin Rönnberg ◽  
Gabriela Calounova ◽  
Bengt Guss ◽  
Anders Lundequist ◽  
Gunnar Pejler
Keyword(s):  
T Cells ◽  
Mast Cell ◽  
Mast Cells ◽  
Serine Proteases ◽  
Cell Activation ◽  
Calcium Ionophore ◽  
Mast Cell Activation ◽  
Activated T Cells ◽  
Mast Cell Protease ◽  
Murine Mast Cell

ABSTRACTGranzymes are serine proteases known mostly for their role in the induction of apoptosis. Granzymes A and B have been extensively studied, but relatively little is known about granzymes C to G and K to M. T cells, lymphohematopoietic stromal cells, and granulated metrial gland cells express granzyme D, but the function of granzyme D is unknown. Here we show that granzyme D is expressed by murine mast cells and that its level of expression correlates positively with the extent of mast cell maturation. Coculture of mast cells with live, Gram-positive bacteria caused a profound, Toll-like receptor 2 (TLR2)-dependent induction of granzyme D expression. Granzyme D expression was also induced by isolated bacterial cell wall components, including lipopolysaccharide (LPS) and peptidoglycan, and by stem cell factor, IgE receptor cross-linking, and calcium ionophore stimulation. Granzyme D was released into the medium in response to mast cell activation. Granzyme D induction was dependent on protein kinase C and nuclear factor of activated T cells (NFAT). Together, these findings identify granzyme D as a novel murine mast cell protease and implicate granzyme D in settings where mast cells are activated, such as bacterial infection and allergy.

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 Borrelia burgdorferiSpirochetes Induce Mast Cell Activation and Cytokine Release

1999 ◽  
Vol 67 (3) ◽  
pp. 1107-1115 ◽  
Author(s):  
Jeffrey Talkington ◽  
Steven P. Nickell
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Cell Activation ◽  
Cell Types ◽  
Host Cells ◽  
Mast Cell Activation ◽  
Cytokine Release ◽  
Necrosis Factor Alpha ◽  
Tnf Α

ABSTRACT The Lyme disease spirochete, Borrelia burgdorferi, is introduced into human hosts via tick bites. Among the cell types present in the skin which may initially contact spirochetes are mast cells. Since spirochetes are known to activate a variety of cell types in vitro, we tested whether B. burgdorferi spirochetes could activate mast cells. We report here that freshly isolated rat peritoneal mast cells or mouse MC/9 mast cells cultured in vitro with live or freeze-thawed B. burgdorferi spirochetes undergo low but detectable degranulation, as measured by [5-3H] hydroxytryptamine release, and they synthesize and secrete the proinflammatory cytokine tumor necrosis factor alpha (TNF-α). In contrast to findings in previous studies, where B. burgdorferi-associated activity was shown to be dependent upon protein lipidation, mast cell TNF-α release was not induced by either lipidated or unlipidated recombinant OspA. This activity was additionally shown to be protease sensitive and surface expressed. Finally, comparisons of TNF-α-inducing activity in known low-, intermediate-, and high-passage B. burgdorferi B31 isolates demonstrated passage-dependent loss of activity, indicating that the activity is probably plasmid encoded. These findings document the presence in low-passage B. burgdorferi spirochetes of a novel lipidation-independent activity capable of inducing cytokine release from host cells.

Abstract 459: Vascular Neuropeptide Y Contributes to Atherosclerotic Plaque Progression and Perivascular Mast Cell Activation

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
H Maxime Lagraauw ◽  
Marijke M Westra ◽  
Martine Bot ◽  
Anouk Wezel ◽  
Peter J Santbrink ◽  
...  
Keyword(s):  
Mast Cell ◽  
Neuropeptide Y ◽  
Atherosclerotic Plaque ◽  
Cell Activation ◽  
Lentiviral Vector ◽  
Cell Types ◽  
Mast Cell Activation ◽  
Plaque Progression ◽  
Plaque Development

Aim: Neuropeptide Y is an abundantly expressed neurotransmitter capable of modulating both immune and metabolic responses related to the development of atherosclerosis. NPY receptors are expressed by a number of vascular wall cell types, among which mast cells. However, the direct effects of NPY on perivascular inflammation and atherosclerotic plaque progression remain to be investigated. In this study we thus aimed to determine whether NPY is expressed in atherosclerotic plaques and to establish its role in atherosclerotic plaque development. Methods and Results: NPY expression was seen to be increased up to 2-fold in unstable human endarterectomy plaques, as compared to stable plaques (p<0.05, n=9-12), and to be significantly upregulated during lesion progression in apoE -/- mice (p<0.001, n=4 per timepoint). In apoE -/- mice overexpression of NPY in the carotid artery by means of local application of a lentiviral vector significantly increased atherosclerotic plaque size compared to controls (54 ± 9 *10 3 μm 2 versus 31 ± 6 *10 3 μm 2 , P<0.05, n=12), while plaque composition was unaffected. Interestingly, perivascular mast cell activation was significantly higher in the NPY-overexpressing mice (48.1 ± 4.0 % versus 30.2 ± 6.0 %, P<0.05), suggesting that NPY may impact plaque progression in part via mast cell activation. Furthermore, in vitro NPY-induced murine mast cell activation resulted in the release of pro-atherogenic mediators including IL-6 (515.0 ± 12.5 pg/ml vs. 87.5 ± 5.0 pg/ml) and tryptase. Conclusions: Our data show that NPY expression is increased during atherogenesis and in particular in unstable plaques. Furthermore, perivascular overexpression of NPY promoted plaque development and perivascular mast cell activation, suggestive of a role for NPY-induced mast cell activation in lesion progression.

scholarly journals Mast cell activation: A complex interplay of positive and negative signaling pathways

2014 ◽  
Vol 44 (9) ◽  
pp. 2558-2566 ◽  
Author(s):  
Riccardo Sibilano ◽  
Barbara Frossi ◽  
Carlo E. Pucillo
Keyword(s):  
Mast Cell ◽  
Signaling Pathways ◽  
Cell Activation ◽  
Mast Cell Activation ◽  
Complex Interplay
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