1,720,999 research outputs found
Mast cell within the microenvironment: Cellular and matrix cross-talk in physiopathological conditions
No full textMast cells are triggered to release histamine and other mediators of inflammation when immunoglobulin E (IgE) receptors on the cell membrane are brought into close proximity, i.e. aggregated. This is usually accomplished in model systems by crosslinking IgE-loaded receptors with multivalent ligands, but can also be achieved by monovalent ligands bound to a fluid lipid bilayer, which may be patterned or homogeneous. With homogeneous membranes, the receptors on the mast cell develop a spatial pattern that bears some similarity to the T cell synapse. Ligand presentation on membranes may be a good model for the interactions of mast cells with various parasites; thus, the development of spatial patterns of receptors and the consequence for mast cell signaling is likely to be important for this most basic mast cell role. In this chapter, we review the role of the spatial organization of signaling components and IgE receptors in mast cell signaling. © 2013 Nova Science Publishers, Inc. All rights reserved
Mast cell/MDSC a liaison immunosuppressive for tumor microenvironment
No full textThe instauration of an immunosuppressive microenvironment is a key event in cancer development and progression. Here, we discuss increasing evidences of the crosstalk between myeloid-derived suppressor cells (MDSCs) and mast cells (MCs) as a new fuel for the cancer immunosuppressive machinery
Coeliac Disease and Mast Cells
Full text linkOver the last decades, there has been an impressive progress in our understanding of coeliac disease pathogenesis and it has become clear that the disorder is the final result of complex interactions of environmental, genetic, and immunological factors. Coeliac disease is now considered a prototype of T-cell-mediated disease characterized by loss of tolerance to dietary gluten and the targeted killing of enterocytes by T-cell receptor αβ intraepithelial lymphocytes. Accumulating evidence, however, indicates that the induction of a gluten-specific T helper-1 response must be preceded by the activation of the innate immune system. Mast cells are key players of the innate immune response and contribute to the pathogenesis of a multitude of diseases. Here, we review the results of studies aimed at investigating the role of mast cells in the pathogenesis of coeliac disease, showing that these cells increase in number during the progression of the disease and contribute to define a pro-inflammatory microenvironment
Selective activation of Fyn/PI3K and p38 MAPK regulates IL-4 production in BMMC under nontoxic stress condition
No full textMast cells have the ability to react to multiple stimuli, implicating these cells in many immune responses. Specific signals from the microenvironment in which mast cells reside can activate different molecular events that govern distinct mast cells responses. We previously demonstrated that hydrogen peroxide (H(2)O(2)) promotes IL-4 and IL-6 mRNA production and potentates FcepsilonRI-induced cytokine release in rat basophilic leukemia RBL-2H3 cells. To further evaluate the effect of an oxidative microenvironment (which is physiologically present in an inflammatory site) on mast cell function and the molecular events responsible for mast cell cytokine production in this environment, we analyzed the effect of H(2)O(2) treatment on IL-4 production in bone marrow-derived, cultured mast cells. Our findings show that nanomolar concentrations of H(2)O(2) induce cytokine secretion and enhance IL-4 production upon FcepsilonRI triggering. Oxidative stimulation activates a distinct signal transduction pathway that induces Fyn/PI3K/Akt activation and the selective phosphorylation of p38 MAP kinase. Moreover, H(2)O(2) induces AP-1 and NFAT complexes that recognize the IL-4 promoter. The absence of Fyn and PI3K or the inhibition of p38 MAPK activity demonstrated that they are essential for H(2)O(2)-driven IL-4 production. These findings show that mast cells can respond to an oxidative microenvironment by initiating specific signals capable of eliciting a selective response. The findings also demonstrate the dominance of the Fyn/p38 MAPK pathway in driving IL-4 production
Mast cell activation: A complex interplay of positive and negative signaling pathways
No full textMast cells regulate the immunological responses causing allergy and autoimmunity, and contribute to the tumor microenvironment through generation and secretion of a broad array of preformed, granule-stored and de novo synthesized bioactive compounds. The release and production of mast cell mediators is the result of a coordinated signaling machinery, followed by the Fc epsilon RI and Fc gamma R antigen ligation. In this review, we present the latest understanding of Fc epsilon RI and Fc gamma R signaling, required for the canonical mast cell activation during allergic responses and anaphylaxis. We then describe the cooperation between the signaling of FcR and other recently characterized membrane-bound receptors (i.e., IL-33R and thymic stromal lymphopoietin receptor) and their role in the chronic settings, where mast cell activation is crucial for the development and the sustainment of chronic diseases, such as asthma or airway inflammation. Finally, we report how the FcR activation could be used as a therapeutic approach to treat allergic and atopic diseases by mast cell inactivation. Understanding the magnitude and the complexity of mast cell signaling is necessary to identify the mechanisms underlying the potential effector and regulatory roles of mast cells in the biology and pathology of those disease settings in which mast cells are activated
Deciphering new mechanisms on T-cell costimulation by human mast cells
No full textIt is well established that full activation of T cells to recognize a specific antigen requires additional signals. These secondary signals are generated by the interaction of costimulatory molecules expressed on APCs. Classical APCs include DCs, macrophages, Langerhans cells, and B cells. However, in recent years, several haematopoietic and nonhaematopoietic cells have been described to express MHC class II antigens and, in appropriate conditions, costimulatory molecules. In this issue, Suurmond et al. [Eur. J. Immunol. 2016. 46: 1132-1141] show, for the first time, that human mast cells not only express costimulatory molecules of the TNF-receptor and CD28 families, but can also costimulate T cells through a yet-to-be-defined CD28-independent interaction
Oxidative stress stimulates IL-4 and IL-6 production in mast cells by an APE/Ref-1-dependent pathway
No full textMast cells are exposed to an oxidative environment in the course of allergic and inflammatory reactions. We have examined the effects of H(2)O(2) stimulation in a primary rat basophilic leukemia cell line (RBL-2H3) and compared with IgE-dependent stimulation. Like IgE stimulation, H(2)O(2) up-regulates IL-4 and IL-6 gene expression and cytokine secretion, shows a little effect on IL-5 but does not induce IL-10 gene expression. Simultaneous H(2)O(2) treatment and FcepsilonRI triggering of mast cells has additive effects on IL-4 expression. In addition, we show that both stimuli induce the nuclear translocation of APE/Ref-1, a bifunctional enzyme that stimulates the DNA-binding activity of several transcription factors through the reduction of highly reactive cysteines. Conditional inactivation of APE/Ref-1 expression abolishes H(2)O(2)-induced IL-4 and IL-6 gene expression but does not affect that induced by FcepsilonRI stimulation. Our findings indicate that oxidative stress activates the gene expression of a specific cytokine pattern in mast cells through an APE/Ref-1-dependent pathway, which is distinct from the one that is activated by FcepsilonRI stimulation. Nonetheless, H(2)O(2) and FcepsilonRI signalings are additive in augmenting IL-4 production. Most importantly, oxidative stress can induce a pro-type 2 inflammatory response from mast cells that is independent of FcepsilonRI stimulation
Co-Occurrence of Chronic Spontaneous Urticaria with Immunoglobulin A Deficiency and Autoimmune Diseases
Full text linkBACKGROUND:
Immunoglobulin (Ig) A deficiency is a primary immunodeficiency in which autoimmunity is frequently observed. Thirty to fifty percent of patients with spontaneous chronic urticaria have autoantibodies that are able to cross-link FcεRI on mast cells and basophils.
METHODS:
We investigated whether spontaneous chronic urticaria in patients with IgA deficiency meets the criteria for autoimmunity. Four patients were screened for positivity to a skin prick test and an autologous serum skin test and for the presence of other autoimmune diseases. Patient sera were tested for the ability to activate basophils and mast cells in vitro by measuring surface CD63 expression and β-hexosaminidase release, respectively.
RESULTS:
The autologous serum test was positive in all patients, and patient sera were found to induce CD63 upregulation on basophils and degranulation of an LAD2 mast cell line. Moreover, all patients were affected by other autoimmune disorders.
CONCLUSION:
For the first time, these data point out chronic autoimmune urticaria in subjects with an IgA deficiency and confirm that different autoimmune disorders are common among patients with an IgA deficiency. Patients with chronic autoimmune spontaneous urticaria should be screened for IgA deficiency, especially if they are affected by other autoimmune disorders. Thus, spontaneous urticaria could mirror more complex systemic diseases, such as immune deficiency
The mast cell: an antenna of the microenvironment that directs the immune response
No full textMast cells (MCs) have long been considered as critical effector cells during immunoglobulin (Ig)E-mediated allergic disease and immune response to parasites. Recent studies, however, suggest that this understanding of MC function is incomplete and does not consider the complex roles that MCs play in adaptive and innate immunity. The added function gives an innovative vision of regulation of immune responses and the development of autoimmune diseases. It had been assumed that the aggregation of Fc epsilon receptor I with IgE and specific antigen is the main stimulus able to induce the MC activation, degranulation, release, and generation of mediators of the allergic reaction. However, MCs exhibit an array of molecules involved in cell-cell and cell-extracellular matrix adhesion, mediating delivery of costimulatory signals that empower those cells with an ability to react to multiple nonspecific and specific stimuli. Their tissue distribution and their capability to release many cytokines after stimulation indicate MCs as potential regulatory linkers between innate and acquired immunity. In this review, we will summarize some findings on the roles of MCs in innate and acquired immunity, on the molecular mechanism and signaling pathways, and on selective signals that induce discrete MC response and its ability to polarize adaptive-immune response
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