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Obeng B, Bennett LJ, West BE, Wagner DJ, Fleming PJ, Tasker MN, Lorenger MK, Smith DR, Systuk T, Plummer SM, Eom J, Paine MD, Frangos CT, Wilczek MP, Shim JK, Maginnis MS, Gosse JA. Antimicrobial cetylpyridinium chloride suppresses mast cell function by targeting tyrosine phosphorylation of Syk kinase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.04.602096. [PMID: 39026716 PMCID: PMC11257455 DOI: 10.1101/2024.07.04.602096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Cetylpyridinium chloride (CPC) is a quaternary ammonium antimicrobial used in numerous personal care products, human food, cosmetic products, and cleaning solutions. Yet, there is minimal published data on CPC effects on eukaryotes, immune signaling, and human health. Previously, we showed that low-micromolar CPC inhibits rat mast cell function by inhibiting antigen (Ag)-stimulated Ca 2+ mobilization, microtubule polymerization, and degranulation. In this study, we extend the findings to human mast cells (LAD2) and present data indicating that CPC's mechanism of action centers on its positively-charged quaternary nitrogen in its pyridinium headgroup. CPC's inhibitory effect is independent of signaling platform receptor architecture. Tyrosine phosphorylation events are a trigger of Ca 2+ mobilization necessary for degranulation. CPC inhibits global tyrosine phosphorylation in Ag-stimulated mast cells. Specifically, CPC inhibits tyrosine phosphorylation of specific key players Syk kinase and LAT, a substrate of Syk. In contrast, CPC does not affect Lyn kinase phosphorylation. Thus, CPC's root mechanism is electrostatic disruption of particular tyrosine phosphorylation events essential for signaling. This work outlines the biochemical mechanisms underlying the effects of CPC on immune signaling and allows the prediction of CPC effects on cell types, like T cells, that share similar signaling elements.
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Deng Y, Jin F, Li X, Park SJ, Chang JH, Kim DY, Kim JA, Nam JW, Choi H, Lee YJ, Chang HW. Sauchinone suppresses FcεRI-mediated mast cell signaling and anaphylaxis through regulation of LKB1/AMPK axis and SHP-1-Syk signaling module. Int Immunopharmacol 2019; 74:105702. [DOI: 10.1016/j.intimp.2019.105702] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 05/27/2019] [Accepted: 06/13/2019] [Indexed: 02/06/2023]
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Abram CL, Lowell CA. Shp1 function in myeloid cells. J Leukoc Biol 2017; 102:657-675. [PMID: 28606940 DOI: 10.1189/jlb.2mr0317-105r] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/01/2017] [Accepted: 05/02/2017] [Indexed: 01/28/2023] Open
Abstract
The motheaten mouse was first described in 1975 as a model of systemic inflammation and autoimmunity, as a result of immune system dysregulation. The phenotype was later ascribed to mutations in the cytoplasmic tyrosine phosphatase Shp1. This phosphatase is expressed widely throughout the hematopoietic system and has been shown to impact a multitude of cell signaling pathways. The determination of which cell types contribute to the different aspects of the phenotype caused by global Shp1 loss or mutation and which pathways within these cell types are regulated by Shp1 is important to further our understanding of immune system regulation. In this review, we focus on the role of Shp1 in myeloid cells and how its dysregulation affects immune function, which can impact human disease.
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Affiliation(s)
- Clare L Abram
- Department of Laboratory Medicine and Immunology Program, University of California, San Francisco, California, USA
| | - Clifford A Lowell
- Department of Laboratory Medicine and Immunology Program, University of California, San Francisco, California, USA
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Choi S, Warzecha C, Zvezdova E, Lee J, Argenty J, Lesourne R, Aravind L, Love PE. THEMIS enhances TCR signaling and enables positive selection by selective inhibition of the phosphatase SHP-1. Nat Immunol 2017; 18:433-441. [PMID: 28250424 PMCID: PMC5807080 DOI: 10.1038/ni.3692] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 01/25/2017] [Indexed: 12/11/2022]
Abstract
THEMIS, a T cell-specific protein with high expression in CD4+CD8+ thymocytes, has a crucial role in positive selection and T cell development. THEMIS lacks defined catalytic domains but contains two tandem repeats of a distinctive module of unknown function (CABIT). Here we found that THEMIS directly regulated the catalytic activity of the tyrosine phosphatase SHP-1. This action was mediated by the CABIT modules, which bound to the phosphatase domain of SHP-1 and promoted or stabilized oxidation of SHP-1's catalytic cysteine residue, which inhibited the tyrosine-phosphatase activity of SHP-1. Deletion of SHP-1 alleviated the developmental block in Themis-/- thymocytes. Thus, THEMIS facilitates thymocyte positive selection by enhancing the T cell antigen receptor signaling response to low-affinity ligands.
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Affiliation(s)
- Seeyoung Choi
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Claude Warzecha
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Ekaterina Zvezdova
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Jan Lee
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Jérémy Argenty
- Centre de Physiopathologie de Toulouse Purpan, Toulouse, France; and Institut National de la Santé et de la Recherche Médicale, U1043, Centre National de la Recherche Scientifique, U5282, and Université de Toulouse, Université Paul Sabatier, Toulouse F-31300, France
| | - Renaud Lesourne
- Centre de Physiopathologie de Toulouse Purpan, Toulouse, France; and Institut National de la Santé et de la Recherche Médicale, U1043, Centre National de la Recherche Scientifique, U5282, and Université de Toulouse, Université Paul Sabatier, Toulouse F-31300, France
| | - L. Aravind
- National Library of Medicine, National Institutes of Health, Bethesda, MD, 20892
| | - Paul E. Love
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
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Li X, Kwon O, Kim DY, Taketomi Y, Murakami M, Chang HW. NecroX-5 suppresses IgE/Ag-stimulated anaphylaxis and mast cell activation by regulating the SHP-1-Syk signaling module. Allergy 2016; 71:198-209. [PMID: 26456627 DOI: 10.1111/all.12786] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND IgE/Ag-stimulated mast cells release various pro-allergic inflammatory mediators, including histamine, eicosanoids, and pro-inflammatory cytokines. NecroX-5, a cell permeable necrosis inhibitor, showed cytoprotective effects in both in vitro and in vivo models. However, the anti-allergic effect of NecroX-5 has not yet been investigated. The aims of this study were to evaluate the anti-allergic activity of NecroX-5 in vivo and to investigate the underlying mechanism in vitro. METHODS The anti-allergic activity of NecroX-5 was evaluated in vitro using bone marrow-derived mast cells (BMMCs) and IgE receptor-bearing RBL-2H3 or KU812 cells and in vivo using a mouse model of passive anaphylaxis. The levels of histamine, eicosanoids (PGD2 and LTC4 ), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were measured using enzyme immunoassay kits. The mechanism underlying the action of NecroX-5 was investigated using immunoblotting, immunoprecipitation, and gene knockdown techniques. RESULTS NecroX-5 markedly inhibited mast cell degranulation and the synthesis of eicosanoids, TNF-α, and IL-6 by suppressing the activation of Syk, LAT, phospholipase Cγ1, MAP kinases, the Akt/NF-κB pathway, and intracellular Ca(2+) mobilization via the activation of phosphatase SHP-1. Oral administration of NecroX-5 effectively suppressed mast cell-dependent passive cutaneous and systemic anaphylactic reactions in a dose-dependent manner. CONCLUSIONS NecroX-5 might be a potential candidate for the development of a novel anti-allergic agent that suppresses IgE-dependent mast cells signaling.
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Affiliation(s)
- X. Li
- College of Pharmacy; Yeungnam University; Gyeongsan Gyeongbuk Korea
| | - O. Kwon
- College of Pharmacy; Yeungnam University; Gyeongsan Gyeongbuk Korea
| | - D. Y. Kim
- College of Pharmacy; Yeungnam University; Gyeongsan Gyeongbuk Korea
| | - Y. Taketomi
- Lipid Metabolism Project; Tokyo Metropolitan Institute of Medical Science; Tokyo Japan
| | - M. Murakami
- Lipid Metabolism Project; Tokyo Metropolitan Institute of Medical Science; Tokyo Japan
| | - H. W. Chang
- College of Pharmacy; Yeungnam University; Gyeongsan Gyeongbuk Korea
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Abstract
For a time, mast cells were viewed as simple granulocytic effector cells that mediate allergic symptoms. More recent discoveries show that mast cells can also function as potent pro- and anti-inflammatory immune regulators in a plethora of human diseases. Much of the current knowledge about mast cell functions comes from studies on rodent models. The membrane receptors for antigen/IgE and growth factors are the core initiators of signaling cascades that trigger various mast cell responses. Yet, the regulation and multifunctionality of key receptor-proximal protein tyrosine phosphorylation events are still not well understood. The roles of the members of the protein tyrosine phosphatase superfamily of enzymes in regulating mast cell development, survival, and immune activation will be reviewed in this chapter.
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Macglashan D, Moore G, Muchhal U. Regulation of IgE-mediated signalling in human basophils by CD32b and its role in Syk down-regulation: basic mechanisms in allergic disease. Clin Exp Allergy 2014; 44:713-23. [PMID: 24734927 DOI: 10.1111/cea.12155] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 05/27/2013] [Accepted: 06/06/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND CD32b has been previously demonstrated to modulate IgE-mediated secretion from human basophils. However, exploration of the implications of this regulation has been limited. One unstudied area is whether regulation of signalling by CD32 also alters some of the phenotypic changes induced by IgE-mediated activation. The reported character of CD32-mediated signal transduction is not clear for human basophils and the two primary mechanisms considered important in this reaction predict different long-term outcomes, notably predicting different outcomes for down-regulation of syk expression. OBJECTIVE Syk expression was considered a unique point of phenotypic control in human basophils and the role of CD32b in its regulation is explored in this study. However, initial pilot studies discovered that IL-3 could markedly up-regulate CD32 expression and first describing the consequences of this up-regulation became an additional focus of this study. METHODS Human basophils were examined for the changes in IgE-mediated signalling during simultaneous engagement of CD32b. RESULTS Preliminary experiments noted that CD32b could be up-regulated by IL-3 (3- to 12-fold). Both natural variation and induced up-regulation of CD32b modulated the efficacy of this receptor to inhibit IgE-mediated release. Signalling induced by engagement of CD32b (lyn, syk, SHP-1, or SHIP1 phosphorylation) was more consistent with a mode of action involving SHIP1 rather than SHP-1. IgE-mediated down-regulation of syk expression was not altered by co-engagement of CD32b, a result also consistent with a SHIP1-dependent mechanism of inhibition. CONCLUSIONS Taken together these results suggest that the combined action of IgE and IgG could generate a natural mechanism, whereby the significant variation in syk expression in allergic subjects occurs without necessarily also inducing mediator release.
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Affiliation(s)
- D Macglashan
- Johns Hopkins Asthma and Allergy Center, Baltimore, MD, USA
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Xu E, Schwab M, Marette A. Role of protein tyrosine phosphatases in the modulation of insulin signaling and their implication in the pathogenesis of obesity-linked insulin resistance. Rev Endocr Metab Disord 2014; 15:79-97. [PMID: 24264858 DOI: 10.1007/s11154-013-9282-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Insulin resistance is a major disorder that links obesity to type 2 diabetes mellitus (T2D). It involves defects in the insulin actions owing to a reduced ability of insulin to trigger key signaling pathways in major metabolic tissues. The pathogenesis of insulin resistance involves several inhibitory molecules that interfere with the tyrosine phosphorylation of the insulin receptor and its downstream effectors. Among those, growing interest has been developed toward the protein tyrosine phosphatases (PTPs), a large family of enzymes that can inactivate crucial signaling effectors in the insulin signaling cascade by dephosphorylating their tyrosine residues. Herein we briefly review the role of several PTPs that have been shown to be implicated in the regulation of insulin action, and then focus on the Src homology 2 (SH2) domain-containing SHP1 and SHP2 enzymes, since recent reports have indicated major roles for these PTPs in the control of insulin action and glucose metabolism. Finally, the therapeutic potential of targeting PTPs for combating insulin resistance and alleviating T2D will be discussed.
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Affiliation(s)
- Elaine Xu
- Department of Medicine, Cardiology Axis of the Institut Universitaire de Cardiologie et de Pneumologie de Québec (Hôpital Laval), Ste-Foy, Québec, Canada, G1V 4G2
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MacGlashan DW. IgE-dependent signaling as a therapeutic target for allergies. Trends Pharmacol Sci 2012; 33:502-9. [PMID: 22749712 PMCID: PMC3427396 DOI: 10.1016/j.tips.2012.06.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 06/02/2012] [Accepted: 06/07/2012] [Indexed: 01/21/2023]
Abstract
Atopic diseases are complex, with many immunological participants, but the central element in their expression is IgE antibody. In an atopic individual, the immune system pathologically reacts to environmental substances by producing IgE, and these allergen-specific IgE antibodies confer to IgE receptor-bearing cells responsiveness to the environmental substances. Mast cells and basophils are central to the immediate hypersensitivity reaction that is mediated by IgE. In humans, there are various other immune cells, notably dendritic cells and B cells, which can also bind IgE. For mast cells, basophils and dendritic cells, the receptor that binds IgE is the high-affinity receptor, FcɛRI. For B cells and a few other cell types, the low affinity receptor, FcɛRII, provides the cell with a means to sense the presence of IgE. This overview will focus on events following activation of the high-affinity receptor because FcɛRI generates the classical immediate hypersensitivity reaction.
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Reactive oxygen species and epidermal growth factor are antagonistic cues controlling SHP-2 dimerization. Mol Cell Biol 2012; 32:1998-2009. [PMID: 22411627 DOI: 10.1128/mcb.06674-11] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The SHP-2 tyrosine phosphatase plays key regulatory roles in the modulation of the cell response to growth factors and cytokines. Over the past decade, the integration of genetic, biochemical, and structural data has helped in interpreting the pathological consequences of altered SHP-2 function. Using complementary approaches, we provide evidence here that endogenous SHP-2 can dimerize through the formation of disulfide bonds that may also involve the catalytic cysteine. We show that the fraction of dimeric SHP-2 is modulated by growth factor stimulation and by the cell redox state. Comparison of the phosphatase activities of the monomeric self-inhibited and dimeric forms indicated that the latter is 3-fold less active, thus pointing to the dimerization process as an additional mechanism for controlling SHP-2 activity. Remarkably, dimers formed by different SHP-2 mutants displaying diverse biochemical properties were found to respond differently to epidermal growth factor (EGF) stimulation. Although this differential behavior cannot be rationalized mechanistically yet, these findings suggest a possible regulatory role of dimerization in SHP-2 function.
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Chihara K, Nakashima K, Takeuchi K, Sada K. Association of 3BP2 with SHP-1 regulates SHP-1-mediated production of TNF-α in RBL-2H3 cells. Genes Cells 2011; 16:1133-45. [DOI: 10.1111/j.1365-2443.2011.01557.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Sancho-Serra MDC, Simarro M, Castells M. Rapid IgE desensitization is antigen specific and impairs early and late mast cell responses targeting FcεRI internalization. Eur J Immunol 2011; 41:1004-13. [PMID: 21360700 DOI: 10.1002/eji.201040810] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 12/03/2010] [Accepted: 01/19/2011] [Indexed: 11/08/2022]
Abstract
Rapid IgE desensitization provides temporary tolerization for patients who have presented severe hypersensitivity reactions to food and drugs, protecting them from anaphylaxis, but the underlying mechanisms are still incompletely understood. Thus, here we develop an effective and reproducible in vitro model of rapid IgE desensitization for mouse BM-derived mast cells (BMMCs) under physiologic calcium conditions, and we characterize its antigen specificity and primary events. BMMCs were challenged with DNP-human serum albumin conjugated (DNP-HSA) and/or OVA antigens, delivered either as a single dose (activation) or as increasing sequential doses (desensitization). Compared to activated cells, desensitized BMMCs had impaired degranulation, calcium flux, secretion of arachidonic acid products, early and late TNF-α production, IL-6 production, and phosphorylation of STAT6 and p38 mitogen-activated protein kinase (p38 MAPK). OVA-desensitized cells responded to DNP and DNP-desensitized cells responded to OVA, proving specificity. Internalization of specific antigen, IgE and high-affinity receptor for IgE (FcεRI) were impaired in desensitized BMMCs. Our results demonstrate that rapid IgE desensitization is antigen specific and inhibits early and late mast cell activation responses and internalization of the antigen/IgE/FcεRI complexes.
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Affiliation(s)
- Maria del Carmen Sancho-Serra
- Division of Rheumatology, Immunology and Allergy, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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Ren L, Chen X, Luechapanichkul R, Selner NG, Meyer TM, Wavreille AS, Chan R, Iorio C, Zhou X, Neel BG, Pei D. Substrate specificity of protein tyrosine phosphatases 1B, RPTPα, SHP-1, and SHP-2. Biochemistry 2011; 50:2339-56. [PMID: 21291263 DOI: 10.1021/bi1014453] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We determined the substrate specificities of the protein tyrosine phosphatases (PTPs) PTP1B, RPTPα, SHP-1, and SHP-2 by on-bead screening of combinatorial peptide libraries and solution-phase kinetic analysis of individually synthesized phosphotyrosyl (pY) peptides. These PTPs exhibit different levels of sequence specificity and catalytic efficiency. The catalytic domain of RPTPα has very weak sequence specificity and is approximately 2 orders of magnitude less active than the other three PTPs. The PTP1B catalytic domain has modest preference for acidic residues on both sides of pY, is highly active toward multiply phosphorylated peptides, but disfavors basic residues at any position, a Gly at the pY-1 position, or a Pro at the pY+1 position. By contrast, SHP-1 and SHP-2 share similar but much narrower substrate specificities, with a strong preference for acidic and aromatic hydrophobic amino acids on both sides of the pY residue. An efficient SHP-1/2 substrate generally contains two or more acidic residues on the N-terminal side and one or more acidic residues on the C-terminal side of pY but no basic residues. Subtle differences exist between SHP-1 and SHP-2 in that SHP-1 has a stronger preference for acidic residues at the pY-1 and pY+1 positions and the two SHPs prefer acidic residues at different positions N-terminal to pY. A survey of the known protein substrates of PTP1B, SHP-1, and SHP-2 shows an excellent agreement between the in vivo dephosphorylation pattern and the in vitro specificity profiles derived from library screening. These results suggest that different PTPs have distinct sequence specificity profiles and the intrinsic activity/specificity of the PTP domain is an important determinant of the enzyme's in vivo substrate specificity.
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Affiliation(s)
- Lige Ren
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
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Abstract
Protein tyrosine phosphatase SHP-1 is an essential regulatory molecule in many different signaling pathways. The biological importance of SHP-1 is underscored by the motheaten mutant mouse strains with immunological disorders involving multiple organs and by the close association of aberrant SHP-1 expression with several human diseases. Recent studies provided some compelling evidence that supports a role of SHP-1 in regulating mast cell development and function and also in regulating type 2 allergic inflammatory responses in both innate and adaptive immune responses. In this article, we summarize the recent advancement of our understanding of this interesting phosphatase in the important area of allergic inflammation.
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Samayawardhena LA, Pallen CJ. PTPalpha activates Lyn and Fyn and suppresses Hck to negatively regulate FcepsilonRI-dependent mast cell activation and allergic responses. THE JOURNAL OF IMMUNOLOGY 2010; 185:5993-6002. [PMID: 20944008 DOI: 10.4049/jimmunol.1001261] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Mast cell activation via FcεRI involves activation of the Src family kinases (SFKs) Lyn, Fyn, and Hck that positively or, in the case of Lyn, negatively regulate cellular responses. Little is known of upstream activators of these SFKs in FcεRI-dependent signaling. We investigated the role of receptor protein tyrosine phosphatase (PTP)α, a well-known activator of SFKs in diverse signaling systems, FcεRI-mediated mast cell activation, and IgE-dependent allergic responses in mice. PTPα(-/-) bone marrow-derived mast cells hyperdegranulate and exhibit increased cytokine and cysteinyl leukotriene secretion, and PTPα(-/-) mice display enhanced IgE-dependent anaphylaxis. At or proximal to FcεRI, PTPα(-/-) cells have reduced IgE-dependent activation of Lyn and Fyn, as well as reduced FcεRI and SHIP phosphorylation. In contrast, Hck and Syk activation is enhanced. Syk hyperactivation correlated with its increased phosphorylation at positive regulatory sites and defective phosphorylation at a negative regulatory site. Distal to FcεRI, we observed increased activation of PI3K and MAPK pathways. These findings demonstrate that PTPα activates the FcεRI-coupled kinases Lyn and Fyn and suppresses Hck activity. Furthermore, the findings indicate that hyperactivation of PTPα(-/-) mast cells and enhanced IgE-dependent allergic responses of PTPα(-/-) mice are due to the ablated function of PTPα as a critical regulator of Lyn negative signaling.
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Affiliation(s)
- Lionel A Samayawardhena
- Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
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Inoue T, Suzuki Y, Mizuno K, Nakata K, Yoshimaru T, Ra C. SHP-1 exhibits a pro-apoptotic function in antigen-stimulated mast cells: Positive regulation of mitochondrial death pathways and negative regulation of survival signaling pathways. Mol Immunol 2009; 47:222-32. [DOI: 10.1016/j.molimm.2009.09.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Accepted: 09/24/2009] [Indexed: 11/16/2022]
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Nakata K, Yoshimaru T, Suzuki Y, Inoue T, Ra C, Yakura H, Mizuno K. Positive and negative regulation of high affinity IgE receptor signaling by Src homology region 2 domain-containing phosphatase 1. THE JOURNAL OF IMMUNOLOGY 2008; 181:5414-24. [PMID: 18832698 DOI: 10.4049/jimmunol.181.8.5414] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Src homology region 2 domain-containing phosphatase 1 (SHP-1), a cytoplasmic protein tyrosine phosphatase, plays an important role for the regulation of signaling from various hematopoietic cell receptors. Although SHP-1 is shown to be a negative signal modulator in mast cells, its precise molecular mechanisms are not well defined. To elucidate how SHP-1 regulates mast cell signaling, we established bone marrow-derived mast cells from SHP-1-deficient motheaten and wild-type mice and analyzed downstream signals induced by cross-linking of high affinity IgE receptor, Fc epsilonRI. Upon Fc epsilonRI ligation, motheaten-derived bone marrow-derived mast cells showed enhanced tyrosine phosphorylation of Src homology region 2 domain-containing leukocyte protein of 76 kDa (SLP-76) and linker for activation of T cells, activation of mitogen-activated protein kinases and gene transcription and production of cytokine. Because the activity of Syk, responsible for the phosphorylation of SLP-76 and linker for activation of T cells, is comparable irrespective of SHP-1, both molecules might be substrates of SHP-1 in mast cells. Interestingly, the absence of SHP-1 expression disrupted the association between SLP-76 and phospholipase Cgamma, which resulted in the decreased phospholipase Cgamma phosphorylation, calcium mobilization, and degranulation. Collectively, these results suggest that SHP-1 regulates Fc epsilonRI-induced downstream signaling events both negatively and positively by functioning as a protein tyrosine phosphatase and as an adaptor protein contributing to the formation of signaling complex, respectively.
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Affiliation(s)
- Kazuko Nakata
- Department of Immunology and Signal Transduction, Tokyo Metropolitan Institute for Neuroscience, Tokyo Metropolitan Organization for Medical Science, Fuchu, Tokyo, Japan
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