Mechanisms of mast cell signaling in anaphylaxis

Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA. .0091-6749
The Journal of allergy and clinical immunology (Impact Factor: 11.25). 10/2009; 124(4):639-46; quiz 647-8. DOI: 10.1016/j.jaci.2009.08.035
Source: PubMed

ABSTRACT The recent development of a consensus definition and proposed diagnostic criteria for anaphylaxis offers promise for research efforts and a better understanding of the epidemiology and pathogenesis of this enigmatic and life-threatening disease. This review examines basic principles and recent research advances in the mechanisms of mast cell signaling believed to underlie anaphylaxis. The unfolding complexity of mast cell signaling suggests that the system is sensitive to regulation by any of several individual signaling pathways and intermediates and that complementary pathways regulate mast cell activation by amplified signals. The signaling events underlying anaphylactic reactions have largely been identified through experiments in genetically modified mice and supported by biochemical studies of mast cells derived from these mice. These studies have revealed that signaling pathways exist to both upregulate and downregulate mast cell responses. In this review we will thus describe the key molecular players in these pathways in the context of anaphylaxis.

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    • "In addition, Ras isoforms play important roles in other biological arenas including the immune system (Alberola-Ila & Hernandez-Hoyos, 2003; Cantrell, 2003). In mast cells, N-Ras and K-Ras are critical for IgE-mediated degranulation (Metcalfe et al., 2009). In lymphocytes, N-Ras and K-Ras regulate signaling downstream of the T-cell antigen receptor leading to cytokine secretion, increased adhesion and clonal proliferation (Genot & Cantrell, 2000). "
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    ABSTRACT: Ras and Rap proteins are closely related small guanosine triphosphatase (GTPases) that share similar effector-binding domains but operate in a very different signaling networks; Ras has a dominant role in cell proliferation, while Rap mediates cell adhesion. Ras and Rap proteins are regulated by several shared processes such as post-translational modification, phosphorylation, activation by guanine exchange factors and inhibition by GTPase-activating proteins. Sub-cellular localization and trafficking of these proteins to and from the plasma membrane are additional important regulatory features that impact small GTPases function. Despite its importance, the trafficking mechanisms of Ras and Rap proteins are not completely understood. Chaperone proteins play a critical role in trafficking of GTPases and will be the focus of the discussion in this work. We will review several aspects of chaperone biology focusing on specificity toward particular members of the small GTPase family. Understanding this specificity should provide key insights into drug development targeting individual small GTPases.
    Critical Reviews in Biochemistry and Molecular Biology 12/2014; DOI:10.3109/10409238.2014.989308 · 5.81 Impact Factor
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    • "Mast cells may be activated by several distinct stimuli acting on numerous receptors on the mast cell surface. The range and nature of mast cell responses to different stimuli can be influenced by intrinsic and microenvironmental factors that affect the expression or functionality of surface receptors and/or signaling molecules that contribute to these responses (Galli et al. 2005b; Metcalfe et al. 2009). "
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    ABSTRACT: Since first described by Paul Ehrlich in 1878, mast cells have been mostly viewed as effectors of allergy. It has been only in the past two decades that mast cells have gained recognition for their involvement in other physiological and pathological processes. Mast cells have a widespread distribution and are found predominantly at the interface between the host and the external environment. Mast cell maturation, phenotype and function are a direct consequence of the local microenvironment and have a marked influence on their ability to specifically recognize and respond to various stimuli through the release of an array of biologically active mediators. These features enable mast cells to act as both first responders in harmful situations as well as to respond to changes in their environment by communicating with a variety of other cells implicated in physiological and immunological responses. Therefore, the critical role of mast cells in both innate and adaptive immunity, including immune tolerance, has gained increased prominence. Conversely, mast cell dysfunction has pointed to these cells as the main offenders in several chronic allergic/inflammatory disorders, cancer and autoimmune diseases. This review summarizes the current knowledge of mast cell function in both normal and pathological conditions with regards to their regulation, phenotype and role.
    Acta histochemica et cytochemica official journal of the Japan Society of Histochemistry and Cytochemistry 07/2014; 62(10). DOI:10.1369/0022155414545334 · 1.22 Impact Factor
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    • "Mast cells are major effector cells in allergic responses by secreting numerous inflammatory mediators [1]. The signaling pathways involved in degranulation have been revealed using RBL(rat basophilic leukemia)-2H3 mast cells, a model of basophils and mast cells [2] [3] [4]. Antigen-driven cross-linking of high affinity immunoglobulin (Ig)E receptors (FceRI) initiates a signaling cascade through activation of the Src family of protein kinases and tyrosine kinases [5] [6]. "
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    ABSTRACT: Diacylglycerol (DAG) is an important lipid that acts as a signaling messenger during mast cell degranulation after allergen cross-linking of immunoglobulin (Ig)E-bound FcεRI receptors. In this study, we determined the role of diacylglycerol kinase (DGK), which negatively regulates DAG-dependent signaling by converting DAG to phosphatidic acid (PA), in the regulation of mast cell degranulation. Treating RBL (rat basophilic leukemia)-2H3 mast cells with a type I DGK inhibitor significantly reduced antigen-induced degranulation and PA production. Among type I DGK isoforms, we observed that DGKα and DGKγ mRNAs were expressed by RBL-2H3 mast cells using reverse transcription polymerase chain reaction. DGKγ knockdown, but not DGKα, by isoform-specific short hairpin RNAs reduced mast cell degranulation and Ca(2+) influxes from the extracellular environment. These results suggest that DGKγ regulates mast cell degranulation after FcεRI cross-linking through mobilization of intracellular Ca(2+) through Ca(2+) influxes.
    Biochemical and Biophysical Research Communications 03/2014; 445(2). DOI:10.1016/j.bbrc.2014.01.197 · 2.28 Impact Factor
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