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Wang C, Nistala R, Cao M, Li DP, Pan Y, Golzy M, Cui Y, Liu Z, Kang X. Repair of Limb Ischemia Is Dependent on Hematopoietic Stem Cell Specific-SHP-1 Regulation of TGF-β1. Arterioscler Thromb Vasc Biol 2023; 43:92-108. [PMID: 36412197 PMCID: PMC10037747 DOI: 10.1161/atvbaha.122.318205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Hematopoietic stem cell (HSC) therapy has shown promise for tissue regeneration after ischemia. Therefore, there is a need to understand mechanisms underlying endogenous HSCs activation in response to ischemic stress and coordination of angiogenesis and repair. SHP-1 plays important roles in HSC quiescence and differentiation by regulation of TGF-β1 signaling. TGF-β1 promotes angiogenesis by stimulating stem cells to secrete growth factors to initiate the formation of blood vessels and later aid in their maturation. We propose that SHP-1 responds to ischemia stress in HSC and progenitor cells (HSPC) via regulation of TGF-β1. METHODS A mouse hind limb ischemia model was used. Local blood perfusion in the limbs was determined using laser doppler perfusion imaging. The number of positive blood vessels per square millimeter, as well as blood vessel diameter (μm) and area (μm2), were calculated. Hematopoietic cells were analyzed using flow cytometry. The bone marrow transplantation assay was performed to measure HSC reconstitution. RESULTS After femoral artery ligation, TGF-β1 was initially decreased in the bone marrow by day 3 of ischemia, followed by an increase on day 7. This pattern was opposite to that in the peripheral blood, which is concordant with the response of HSC to ischemic stress. In contrast, SHP-1 deficiency in HSC is associated with irreversible activation of HSPCs in the bone marrow and increased circulating HSPCs in peripheral blood following limb ischemia. In addition, there was augmented auto-induction of TGF-β1 and sustained inactivation of SHP-1-Smad2 signaling, which impacted TGF-β1 expression in HSPCs in circulation. Importantly, restoration of normal T GF-β1 oscillations helped in the recovery of limb repair and function. CONCLUSIONS HSPC-SHP-1-mediated regulation of TGF-β1 in both bone marrow and peripheral blood is required for a normal response to ischemic stress.
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Affiliation(s)
- Chen Wang
- Center for Precision Medicine (C.W., R.N., M.C., D.-P.L., Y.P., Y.C., Z.L., X.K.), Department of Medicine, University of Missouri School of Medicine, Columbia
| | - Ravi Nistala
- Center for Precision Medicine (C.W., R.N., M.C., D.-P.L., Y.P., Y.C., Z.L., X.K.), Department of Medicine, University of Missouri School of Medicine, Columbia
- Division of Nephrology (R.N.), Department of Medicine, University of Missouri School of Medicine, Columbia
| | - Min Cao
- Center for Precision Medicine (C.W., R.N., M.C., D.-P.L., Y.P., Y.C., Z.L., X.K.), Department of Medicine, University of Missouri School of Medicine, Columbia
| | - De-Pei Li
- Center for Precision Medicine (C.W., R.N., M.C., D.-P.L., Y.P., Y.C., Z.L., X.K.), Department of Medicine, University of Missouri School of Medicine, Columbia
| | - Yi Pan
- Center for Precision Medicine (C.W., R.N., M.C., D.-P.L., Y.P., Y.C., Z.L., X.K.), Department of Medicine, University of Missouri School of Medicine, Columbia
| | - Mojgan Golzy
- Department of Family and Community Medicine - Biostatistics Unit, School of Medicine, University of Missouri, Columbia (M.G.)
| | - Yuqi Cui
- Center for Precision Medicine (C.W., R.N., M.C., D.-P.L., Y.P., Y.C., Z.L., X.K.), Department of Medicine, University of Missouri School of Medicine, Columbia
- Division of Cardiovascular Medicine (Y.C., Z.L.), Department of Medicine, University of Missouri School of Medicine, Columbia
| | - Zhenguo Liu
- Center for Precision Medicine (C.W., R.N., M.C., D.-P.L., Y.P., Y.C., Z.L., X.K.), Department of Medicine, University of Missouri School of Medicine, Columbia
- Division of Cardiovascular Medicine (Y.C., Z.L.), Department of Medicine, University of Missouri School of Medicine, Columbia
| | - XunLei Kang
- Center for Precision Medicine (C.W., R.N., M.C., D.-P.L., Y.P., Y.C., Z.L., X.K.), Department of Medicine, University of Missouri School of Medicine, Columbia
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2
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DeLuca JM, Murphy MK, Wang X, Wilson TJ. FCRL1 Regulates B Cell Receptor-Induced ERK Activation through GRB2. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2021; 207:2688-2698. [PMID: 34697226 PMCID: PMC8629370 DOI: 10.4049/jimmunol.2100218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 09/17/2021] [Indexed: 11/19/2022]
Abstract
Regulation of BCR signaling has important consequences for generating effective Ab responses to pathogens and preventing production of autoreactive B cells during development. Currently defined functions of Fc receptor-like (FCRL) 1 include positive regulation of BCR-induced calcium flux, proliferation, and Ab production; however, the mechanistic basis of FCRL1 signaling and its contributions to B cell development remain undefined. Molecular characterization of FCRL1 signaling shows phosphotyrosine-dependent associations with GRB2, GRAP, SHIP-1, and SOS1, all of which can profoundly influence MAPK signaling. In contrast with previous characterizations of FCRL1 as a strictly activating receptor, we discover a role for FCRL1 in suppressing ERK activation under homeostatic and BCR-stimulated conditions in a GRB2-dependent manner. Our analysis of B cells in Fcrl1 -/- mice shows that ERK suppression by FCRL1 is associated with a restriction in the number of cells surviving splenic maturation in vivo. The capacity of FCRL1 to modulate ERK activation presents a potential for FCRL1 to be a regulator of peripheral B cell tolerance, homeostasis, and activation.
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Affiliation(s)
- Jenna M DeLuca
- Department of Microbiology, Miami University, Oxford, OH
| | | | - Xin Wang
- Department of Microbiology, Miami University, Oxford, OH
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3
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Estus S, Shaw BC, Devanney N, Katsumata Y, Press EE, Fardo DW. Evaluation of CD33 as a genetic risk factor for Alzheimer's disease. Acta Neuropathol 2019; 138:187-199. [PMID: 30949760 PMCID: PMC7035471 DOI: 10.1007/s00401-019-02000-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/22/2019] [Accepted: 03/30/2019] [Indexed: 12/23/2022]
Abstract
In 2011, genome-wide association studies implicated a polymorphism near CD33 as a genetic risk factor for Alzheimer's disease. This finding sparked interest in this member of the sialic acid-binding immunoglobulin-type lectin family which is linked to innate immunity. Subsequent studies found that CD33 is expressed in microglia in the brain and then investigated the molecular mechanism underlying the CD33 genetic association with Alzheimer's disease. The allele that protects from Alzheimer's disease acts predominately to increase a CD33 isoform lacking exon 2 at the expense of the prototypic, full-length CD33 that contains exon 2. Since this exon encodes the sialic acid ligand-binding domain, the finding that the loss of exon 2 was associated with decreased Alzheimer's disease risk was interpreted as meaning that a decrease in functional CD33 and its associated immune suppression was protective from Alzheimer's disease. However, this interpretation may need to be reconsidered given current findings that a genetic deletion which abrogates CD33 is not associated with Alzheimer's disease risk. Therefore, integrating currently available findings leads us to propose a model wherein the CD33 isoform lacking the ligand-binding domain represents a gain of function variant that reduces Alzheimer's disease risk.
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Affiliation(s)
- Steven Estus
- Department of Physiology and Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA.
| | - Benjamin C Shaw
- Department of Physiology and Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Nicholas Devanney
- Department of Physiology and Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Yuriko Katsumata
- Department of Biostatistics and Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | | | - David W Fardo
- Department of Biostatistics and Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
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4
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Anania JC, Chenoweth AM, Wines BD, Hogarth PM. The Human FcγRII (CD32) Family of Leukocyte FcR in Health and Disease. Front Immunol 2019; 10:464. [PMID: 30941127 PMCID: PMC6433993 DOI: 10.3389/fimmu.2019.00464] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 02/21/2019] [Indexed: 12/15/2022] Open
Abstract
FcγRs have been the focus of extensive research due to their key role linking innate and humoral immunity and their implication in both inflammatory and infectious disease. Within the human FcγR family FcγRII (activatory FcγRIIa and FcγRIIc, and inhibitory FcγRIIb) are unique in their ability to signal independent of the common γ chain. Through improved understanding of the structure of these receptors and how this affects their function we may be able to better understand how to target FcγR specific immune activation or inhibition, which will facilitate in the development of therapeutic monoclonal antibodies in patients where FcγRII activity may be desirable for efficacy. This review is focused on roles of the human FcγRII family members and their link to immunoregulation in healthy individuals and infection, autoimmunity and cancer.
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Affiliation(s)
- Jessica C Anania
- Centre for Biomedical Research, Burnet Institute, Melbourne, VIC, Australia.,Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Alicia M Chenoweth
- Centre for Biomedical Research, Burnet Institute, Melbourne, VIC, Australia.,Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Bruce D Wines
- Centre for Biomedical Research, Burnet Institute, Melbourne, VIC, Australia.,Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, VIC, Australia.,Department of Pathology, The University of Melbourne, Melbourne, VIC, Australia
| | - P Mark Hogarth
- Centre for Biomedical Research, Burnet Institute, Melbourne, VIC, Australia.,Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, VIC, Australia.,Department of Pathology, The University of Melbourne, Melbourne, VIC, Australia
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5
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Wieland A, Ahmed R. Fc Receptors in Antimicrobial Protection. Curr Top Microbiol Immunol 2019; 423:119-150. [DOI: 10.1007/82_2019_154] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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6
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Kim HS, Nam ST, Mun SH, Lee SK, Kim HW, Park YH, Kim B, Won KJ, Kim HR, Park YM, Kim HS, Beaven MA, Kim YM, Choi WS. DJ-1 controls bone homeostasis through the regulation of osteoclast differentiation. Nat Commun 2017; 8:1519. [PMID: 29142196 PMCID: PMC5688089 DOI: 10.1038/s41467-017-01527-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 09/25/2017] [Indexed: 11/09/2022] Open
Abstract
Receptor activator of NF-kB ligand (RANKL) generates intracellular reactive oxygen species (ROS), which increase RANKL-mediated signaling in osteoclast (OC) precursor bone marrow macrophages (BMMs). Here we show that a ROS scavenging protein DJ-1 negatively regulates RANKL-driven OC differentiation, also called osteoclastogenesis. DJ-1 ablation in mice leads to a decreased bone volume and an increase in OC numbers. In vitro, the activation of RANK-dependent signals is enhanced in DJ-1-deficient BMMs as compared to wild-type BMMs. DJ-1 suppresses the activation of both RANK-TRAF6 and RANK-FcRγ/Syk signaling pathways because of activation of Src homology region 2 domain-containing phosphatase-1, which is inhibited by ROS. Ablation of DJ-1 in mouse models of arthritis and RANKL-induced bone disease leads to an increase in the number of OCs, and exacerbation of bone damage. Overall, our results suggest that DJ-1 plays a role in bone homeostasis in normal physiology and in bone-associated pathology by negatively regulating osteoclastogenesis. Osteoclasts are involved in arthritis, and their differentiation depends on RANKL signaling. The author show that the ROS-scavenging protein DJ-1 negatively regulates RANKL signaling and that its ablation increases osteoclast numbers and exacerbates bone damage in mouse models of arthritis.
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Affiliation(s)
- Hyuk Soon Kim
- Department of Immunology and Physiology, School of Medicine, Konkuk University, Chungju, 380-701, Republic of Korea
| | - Seung Taek Nam
- Department of Immunology and Physiology, School of Medicine, Konkuk University, Chungju, 380-701, Republic of Korea
| | - Se Hwan Mun
- Department of Immunology and Physiology, School of Medicine, Konkuk University, Chungju, 380-701, Republic of Korea.,Department of Medicine, University of Connecticut Health Center, 263 Farmington Ave, Farmington, CT, 06030, USA
| | - Sun-Kyeong Lee
- Department of Medicine, University of Connecticut Health Center, 263 Farmington Ave, Farmington, CT, 06030, USA
| | - Hyun Woo Kim
- Department of Immunology and Physiology, School of Medicine, Konkuk University, Chungju, 380-701, Republic of Korea
| | - Young Hwan Park
- Department of Immunology and Physiology, School of Medicine, Konkuk University, Chungju, 380-701, Republic of Korea
| | - Bokyung Kim
- Department of Immunology and Physiology, School of Medicine, Konkuk University, Chungju, 380-701, Republic of Korea
| | - Kyung-Jong Won
- Department of Immunology and Physiology, School of Medicine, Konkuk University, Chungju, 380-701, Republic of Korea
| | - Hae-Rim Kim
- Department of Rheumatology, School of Medicine, Konkuk University, Chungju, 380-701, Republic of Korea
| | - Yeong-Min Park
- Department of Immunology and Physiology, School of Medicine, Konkuk University, Chungju, 380-701, Republic of Korea
| | - Hyung Sik Kim
- Department of Toxicology, School of Pharmacy, Sungkyunkwan University, Suwon, 440-746, Republic of Korea
| | - Michael A Beaven
- Laboratory of Molecular Immunology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Young Mi Kim
- Department of Preventive Pharmacy, College of Pharmacy, Duksung Women's University, Seoul, 132-714, Republic of Korea
| | - Wahn Soo Choi
- Department of Immunology and Physiology, School of Medicine, Konkuk University, Chungju, 380-701, Republic of Korea.
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7
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Levin R, Grinstein S, Canton J. The life cycle of phagosomes: formation, maturation, and resolution. Immunol Rev 2017; 273:156-79. [PMID: 27558334 DOI: 10.1111/imr.12439] [Citation(s) in RCA: 194] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Phagocytosis, the regulated uptake of large particles (>0.5 μm in diameter), is essential for tissue homeostasis and is also an early, critical component of the innate immune response. Phagocytosis can be conceptually divided into three stages: phagosome, formation, maturation, and resolution. Each of these involves multiple reactions that require exquisite spatial and temporal orchestration. The molecular events underlying these stages are being unraveled and the current state of knowledge is briefly summarized in this article.
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Affiliation(s)
- Roni Levin
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
| | - Johnathan Canton
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada
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8
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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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9
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Getahun A, Cambier JC. Of ITIMs, ITAMs, and ITAMis: revisiting immunoglobulin Fc receptor signaling. Immunol Rev 2016; 268:66-73. [PMID: 26497513 DOI: 10.1111/imr.12336] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Receptors for immunoglobulin Fc regions play multiple critical roles in the immune system, mediating functions as diverse as phagocytosis, triggering degranulation of basophils and mast cells, promoting immunoglobulin class switching, and preventing excessive activation. Transmembrane signaling associated with these functions is mediated primarily by two amino acid sequence motifs, ITAMs (immunoreceptor tyrosine-based activation motifs) and ITIMs (immunoreceptor tyrosine-based inhibition motifs) that act as the receptors' interface with activating and inhibitory signaling pathways, respectively. While ITAMs mobilize activating tyrosine kinases and their consorts, ITIMs mobilize opposing tyrosine and inositol-lipid phosphatases. In this review, we will discuss our current understanding of signaling by these receptors/motifs and their sometimes blurred lines of function.
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Affiliation(s)
- Andrew Getahun
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
| | - John C Cambier
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
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10
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Fatehchand K, Ren L, Elavazhagan S, Fang H, Mo X, Vasilakos JP, Dietsch GN, Hershberg RM, Tridandapani S, Butchar JP. Toll-like Receptor 4 Ligands Down-regulate Fcγ Receptor IIb (FcγRIIb) via MARCH3 Protein-mediated Ubiquitination. J Biol Chem 2015; 291:3895-904. [PMID: 26694610 DOI: 10.1074/jbc.m115.701151] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Indexed: 11/06/2022] Open
Abstract
Monocytes and macrophages are critical for the effectiveness of monoclonal antibody therapy. Responses to antibody-coated tumor cells are largely mediated by Fcγ receptors (FcγRs), which become activated upon binding to immune complexes. FcγRIIb is an inhibitory FcγR that negatively regulates these responses, and it is expressed on monocytes and macrophages. Therefore, deletion or down-regulation of this receptor may substantially enhance therapeutic outcomes. Here we screened a panel of Toll-like receptor (TLR) agonists and found that those selective for TLR4 and TLR8 could significantly down-regulate the expression of FcγRIIb. Upon further examination, we found that treatment of monocytes with TLR4 agonists could lead to the ubiquitination of FcγRIIb protein. A search of our earlier microarray database of monocytes activated with the TLR7/8 agonist R-848 (in which FcγRIIb was down-regulated) revealed an up-regulation of membrane-associated ring finger (C3HC4) 3 (MARCH3), an E3 ubiquitin ligase. Therefore, we tested whether LPS treatment could up-regulate MARCH3 in monocytes and whether this E3 ligase was involved with LPS-mediated FcγRIIb down-regulation. The results showed that LPS activation of TLR4 significantly increased MARCH3 expression and that siRNA against MARCH3 prevented the decrease in FcγRIIb following LPS treatment. These data suggest that activation of TLR4 on monocytes can induce a rapid down-regulation of FcγRIIb protein and that this involves ubiquitination.
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Affiliation(s)
| | - Li Ren
- the Key Laboratory for Molecular Enzymology and Engineering, Ministry of Education, Jilin University, Changchun, 130000 Jilin, China
| | | | | | - Xiaokui Mo
- Center for Biostatistics, Ohio State University, Columbus, Ohio 43210
| | - John P Vasilakos
- the 3M Drug Delivery Systems Division, St. Paul, Minnesota 55144, and
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11
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Ben Mkaddem S, Hayem G, Jönsson F, Rossato E, Boedec E, Boussetta T, El Benna J, Launay P, Goujon JM, Benhamou M, Bruhns P, Monteiro RC. Shifting FcγRIIA-ITAM from activation to inhibitory configuration ameliorates arthritis. J Clin Invest 2014; 124:3945-59. [PMID: 25061875 DOI: 10.1172/jci74572] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 05/30/2014] [Indexed: 01/22/2023] Open
Abstract
Rheumatoid arthritis-associated (RA-associated) inflammation is mediated through the interaction between RA IgG immune complexes and IgG Fc receptors on immune cells. Polymorphisms within the gene encoding the human IgG Fc receptor IIA (hFcγRIIA) are associated with an increased risk of developing RA. Within the hFcγRIIA intracytoplasmic domain, there are 2 conserved tyrosine residues arranged in a noncanonical immunoreceptor tyrosine-based activation motif (ITAM). Here, we reveal that inhibitory engagement of the hFcγRIIA ITAM either with anti-hFcγRII F(ab')2 fragments or intravenous hIgG (IVIg) ameliorates RA-associated inflammation, and this effect was characteristic of previously described inhibitory ITAM (ITAMi) signaling for hFcαRI and hFcγRIIIA, but only involves a single tyrosine. In hFcγRIIA-expressing mice, arthritis induction was inhibited following hFcγRIIA engagement. Moreover, hFcγRIIA ITAMi-signaling reduced ROS and inflammatory cytokine production through inhibition of guanine nucleotide exchange factor VAV-1 and IL-1 receptor-associated kinase 1 (IRAK-1), respectively. ITAMi signaling was mediated by tyrosine 304 (Y304) within the hFcγRIIA ITAM, which was required for recruitment of tyrosine kinase SYK and tyrosine phosphatase SHP-1. Anti-hFcγRII F(ab')2 treatment of inflammatory synovial cells from RA patients inhibited ROS production through induction of ITAMi signaling. These data suggest that shifting constitutive hFcγRIIA-mediated activation to ITAMi signaling could ameliorate RA-associated inflammation.
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12
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Joshi S, Singh AR, Zulcic M, Durden DL. A PKC-SHP1 signaling axis desensitizes Fcγ receptor signaling by reducing the tyrosine phosphorylation of CBL and regulates FcγR mediated phagocytosis. BMC Immunol 2014; 15:18. [PMID: 24886428 PMCID: PMC4017086 DOI: 10.1186/1471-2172-15-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 04/23/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Fcγ receptors mediate important biological signals in myeloid cells including the ingestion of microorganisms through a process of phagocytosis. It is well-known that Fcγ receptor (FcγR) crosslinking induces the tyrosine phosphorylation of CBL which is associated with FcγR mediated phagocytosis, however how signaling molecules coordinate to desensitize these receptors is unclear. An investigation of the mechanisms involved in receptor desensitization will provide new insight into potential mechanisms by which signaling molecules may downregulate tyrosine phosphorylation dependent signaling events to terminate important signaling processes. RESULTS Using the U937IF cell line, we observed that FcγR1 crosslinking induces the tyrosine phosphorylation of CBL, which is maximal at 5 min. followed by a kinetic pattern of dephosphorylation. An investigation of the mechanisms involved in receptor desensitization revealed that pretreatment of U937IF or J774 cells with PMA followed by Fcγ receptor crosslinking results in the reduced tyrosine phosphorylation of CBL and the abrogation of downstream signals, such as CBL-CRKL binding, Rac-GTP activation and the phagocytic response. Pretreatment of J774 cells with GF109203X, a PKC inhibitor was observed to block dephosphorylation of CBL and rescued the phagocytic response. We demonstrate that the PKC induced desensitization of FcγR/ phagocytosis is associated with the inactivation of Rac-GTP, which is deactivated in a hematopoietic specific phosphatase SHP1 dependent manner following ITAM stimulation. The effect of PKC on FcγR signaling is augmented by the transfection of catalytically active SHP1 and not by the transfection of catalytic dead SHP1 (C124S). CONCLUSIONS Our results suggest a functional model by which PKC interacts with SHP1 to affect the phosphorylation state of CBL, the activation state of Rac and the negative regulation of ITAM signaling i.e. Fcγ receptor mediated phagocytosis. These findings suggest a mechanism for Fcγ receptor desensitization by which a serine-threonine kinase e.g. PKC downregulates tyrosine phosphorylation dependent signaling events via the reduced tyrosine phosphorylation of the complex adapter protein, CBL.
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Affiliation(s)
| | | | | | - Donald L Durden
- UCSD Department of Pediatrics, Moores UCSD Cancer Center, University of California School of Medicine, San Diego, CA 92093, USA.
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13
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Ming‐Lum A, Shojania S, So E, McCarrell E, Shaw E, Vu D, Wang I, McIntosh LP, Mui AL. A pleckstrin homology‐related domain in SHIP1 mediates membrane localization during Fcγ receptor‐induced phagocytosis. FASEB J 2012; 26:3163-77. [DOI: 10.1096/fj.11-201475] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Andrew Ming‐Lum
- Immunity and Infection Research CentreVancouver Coastal Health Research Institute Vancouver British Columbia Canada
- Department of SurgeryUniversity of British Columbia Vancouver British Columbia Canada
| | - Shaheen Shojania
- Department of Biochemistry and Molecular BiologyUniversity of British Columbia Vancouver British Columbia Canada
| | - Eva So
- Immunity and Infection Research CentreVancouver Coastal Health Research Institute Vancouver British Columbia Canada
- Department of SurgeryUniversity of British Columbia Vancouver British Columbia Canada
| | - Erin McCarrell
- Immunity and Infection Research CentreVancouver Coastal Health Research Institute Vancouver British Columbia Canada
- Department of SurgeryUniversity of British Columbia Vancouver British Columbia Canada
| | - Eileen Shaw
- Immunity and Infection Research CentreVancouver Coastal Health Research Institute Vancouver British Columbia Canada
- Department of SurgeryUniversity of British Columbia Vancouver British Columbia Canada
| | - David Vu
- Immunity and Infection Research CentreVancouver Coastal Health Research Institute Vancouver British Columbia Canada
- Department of SurgeryUniversity of British Columbia Vancouver British Columbia Canada
| | - Ida Wang
- Immunity and Infection Research CentreVancouver Coastal Health Research Institute Vancouver British Columbia Canada
- Department of SurgeryUniversity of British Columbia Vancouver British Columbia Canada
| | - Lawrence P. McIntosh
- Department of Biochemistry and Molecular BiologyUniversity of British Columbia Vancouver British Columbia Canada
- Department of ChemistryUniversity of British Columbia Vancouver British Columbia Canada
| | - Alice L.‐F. Mui
- Immunity and Infection Research CentreVancouver Coastal Health Research Institute Vancouver British Columbia Canada
- Department of SurgeryUniversity of British Columbia Vancouver British Columbia Canada
- Department of Biochemistry and Molecular BiologyUniversity of British Columbia Vancouver British Columbia Canada
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14
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Flannagan RS, Jaumouillé V, Grinstein S. The Cell Biology of Phagocytosis. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2012; 7:61-98. [PMID: 21910624 DOI: 10.1146/annurev-pathol-011811-132445] [Citation(s) in RCA: 652] [Impact Index Per Article: 54.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ronald S. Flannagan
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada;
| | - Valentin Jaumouillé
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada;
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada;
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15
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Wang J, Wu Y, Hu H, Wang W, Lu Y, Mao H, Liu X, Liu Z, Chen BG. Syk protein tyrosine kinase involves PECAM-1 signaling through tandem immunotyrosine inhibitory motifs in human THP-1 macrophages. Cell Immunol 2011; 272:39-44. [PMID: 22000807 DOI: 10.1016/j.cellimm.2011.09.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 08/05/2011] [Accepted: 09/19/2011] [Indexed: 11/18/2022]
Abstract
Although recent evidence supports a functional relationship between platelet endothelial cell adhesion molecule (PECAM-1) and Syk tyrosine kinase, little is known about the interaction of Syk with PECAM-1. We report that down-regulation of Syk inhibits the spreading of human THP-1 macrophage cells. Moreover, our data indicate that Syk binds PECAM-1 through its immune tyrosine-based inhibitory motif (ITIM), and dual phosphorylation of the ITIM domain of PECAM-1 leads to activation of Syk. Our results indicate that the distance between the phosphotyrosines could be up to 22 amino acids in length, depending on the conformational flexibility, and that the dual ITIM tyrosine motifs of PECAM-1 facilitate immunoreceptor tyrosine-based activation motif-like signaling. The preferential binding of PECAM-1 to Src homology region 2 domain-containing phosphatase-2 or Syk may depend on their relative affinities, and could provide a mechanism by which signal transduction from PECAM-1 is internally regulated by both positive and negative signaling enzymes.
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Affiliation(s)
- Junchen Wang
- Department of Surgery and Pathology, Shanghai East Hospital, Tongji University School of Medicine, 150 Jimo Road, Pudong New District, Shanghai, PR China
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16
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Lawrence DW, Koenig JM. Enhanced Phagocytosis in Neonatal Monocyte-Derived Macrophages is Associated with Impaired SHP-1 Signaling. Immunol Invest 2011; 41:129-43. [DOI: 10.3109/08820139.2011.595471] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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17
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Park H, Ishihara D, Cox D. Regulation of tyrosine phosphorylation in macrophage phagocytosis and chemotaxis. Arch Biochem Biophys 2011; 510:101-11. [PMID: 21356194 PMCID: PMC3114168 DOI: 10.1016/j.abb.2011.02.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 02/15/2011] [Accepted: 02/18/2011] [Indexed: 12/22/2022]
Abstract
Macrophages display a large variety of surface receptors that are critical for their normal cellular functions in host defense, including finding sites of infection (chemotaxis) and removing foreign particles (phagocytosis). However, inappropriate regulation of these processes can lead to human diseases. Many of these receptors utilize tyrosine phosphorylation cascades to initiate and terminate signals leading to cell migration and clearance of infection. Actin remodeling dominates these processes and many regulators have been identified. This review focuses on how tyrosine kinases and phosphatases regulate actin dynamics leading to macrophage chemotaxis and phagocytosis.
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Affiliation(s)
- Haein Park
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Dan Ishihara
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Dianne Cox
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
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18
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Abstract
Immunoreceptor tyrosine-based activation motifs (ITAMs) are used by multiple receptors to activate immune cells. However, ITAM-associated receptors can have paradoxically inhibitory effects, which have been implicated in regulation of inflammatory responses, but mechanisms of inhibitory signaling are poorly understood. New evidence shows that low avidity ligation of the ITAM-associated immunoglobulin A receptor FcαRI (transient engagement of small numbers of FcαRIs) results in translocation of FcαRI and the associated inhibitory Src homology 2 (SH2) domain-containing phosphatase-1 (SHP-1) to membrane lipid rafts. Subsequent ligation of activating receptors results in their colocalization with FcαRI and SHP-1 and trafficking to an inhibitory intracellular compartment termed the inhibisome. Thus, ITAM suppressive signals subvert the activating function of rafts to promote incorporation of receptors into supramolecular domains where signaling molecules are deactivated by SHP-1.
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Affiliation(s)
- Lionel B Ivashkiv
- Arthritis and Tissue Degeneration Program, Hospital for Special Surgery, Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, 535 East 70th Street, New York, NY 10021, USA.
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19
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Rajaram MVS, Butchar JP, Parsa KVL, Cremer TJ, Amer A, Schlesinger LS, Tridandapani S. Akt and SHIP modulate Francisella escape from the phagosome and induction of the Fas-mediated death pathway. PLoS One 2009; 4:e7919. [PMID: 19936232 PMCID: PMC2775408 DOI: 10.1371/journal.pone.0007919] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Accepted: 10/27/2009] [Indexed: 12/13/2022] Open
Abstract
Francisella tularensis infects macrophages and escapes phago-lysosomal fusion to replicate within the host cytosol, resulting in host cell apoptosis. Here we show that the Fas-mediated death pathway is activated in infected cells and correlates with escape of the bacterium from the phagosome and the bacterial burden. Our studies also demonstrate that constitutive activation of Akt, or deletion of SHIP, promotes phago-lysosomal fusion and limits bacterial burden in the host cytosol, and the subsequent induction of Fas expression and cell death. Finally, we show that phagosomal escape/intracellular bacterial burden regulate activation of the transcription factors sp1/sp3, leading to Fas expression and cell death. These data identify for the first time host cell signaling pathways that regulate the phagosomal escape of Francisella, leading to the induction of Fas and subsequent host cell death.
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Affiliation(s)
- Murugesan V. S. Rajaram
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Jonathan P. Butchar
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Kishore V. L. Parsa
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, United States of America
| | - Thomas J. Cremer
- Molecular, Cellular, and Developmental Biology Program, The Ohio State University, Columbus, Ohio, United States of America
| | - Amal Amer
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio, United States of America
- Center for Microbial Interface Biology, The Ohio State University, Columbus, Ohio, United States of America
| | - Larry S. Schlesinger
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio, United States of America
- Center for Microbial Interface Biology, The Ohio State University, Columbus, Ohio, United States of America
| | - Susheela Tridandapani
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio, United States of America
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, United States of America
- Molecular, Cellular, and Developmental Biology Program, The Ohio State University, Columbus, Ohio, United States of America
- Center for Microbial Interface Biology, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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20
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Blank U, Launay P, Benhamou M, Monteiro RC. Inhibitory ITAMs as novel regulators of immunity. Immunol Rev 2009; 232:59-71. [DOI: 10.1111/j.1600-065x.2009.00832.x] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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21
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Marois L, Vaillancourt M, Marois S, Proulx S, Paré G, Rollet-Labelle E, Naccache PH. The ubiquitin ligase c-Cbl down-regulates FcgammaRIIa activation in human neutrophils. THE JOURNAL OF IMMUNOLOGY 2009; 182:2374-84. [PMID: 19201892 DOI: 10.4049/jimmunol.0801420] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Little is known about the mechanisms that arrest FcgammaRIIa signaling in human neutrophils once engaged by immune complexes or opsonized pathogens. In our previous studies, we observed a loss of immunoreactivity of Abs directed against FcgammaRIIa following its cross-linking. In this study, we report on the mechanisms involved in this event. A stimulated internalization of FcgammaRIIa leading to the down-regulation of its surface expression was observed by flow cytometry and confocal microscopy. Immunoprecipitation of the receptor showed that FcgammaRIIa is ubiquitinated after stimulation. MG132 and clasto-lactacystin beta-lactone inhibited the loss of immunoreactivity of FcgammaRIIa, suggesting that this receptor was down-regulated via the proteasomal pathway. The E3 ubiquitin ligase c-Cbl was found to translocate from the cytosol to the plasma membrane following receptor cross-linking. Furthermore, c-Cbl was recruited to the same subset of high-density, detergent-resistant membrane fractions as stimulated FcgammaRIIa itself. Silencing the expression of c-Cbl by small interfering RNA decreased FcgammaRIIa ubiquitination and prevented its degradation without affecting the internalisation process. It also prolonged the stimulation of the tyrosine phosphorylation response to the cross-linking of the receptor. We conclude that c-Cbl mediates the ubiquitination of stimulated FcgammaRIIa and thereby contributes to the termination of FcgammaRIIa signaling via its proteasomal degradation, thus leading to the down-regulation of neutrophil signalisation and function (phagocytosis) through this receptor.
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Affiliation(s)
- Louis Marois
- Centre de recherche en rhumatologie et immunologie, Centre de recherche du Centre hospitalier universitaire de Québec, Department of Medicine, Faculty of Medicine, Laval University, Quebec, Canada
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22
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Cady CT, Rice JS, Ott VL, Cambier JC. Regulation of hematopoietic cell function by inhibitory immunoglobulin G receptors and their inositol lipid phosphatase effectors. Immunol Rev 2008; 224:44-57. [PMID: 18759919 DOI: 10.1111/j.1600-065x.2008.00663.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Numerous autoimmune and inflammatory disorders stem from the dysregulation of hematopoietic cell activation. The activity of inositol lipid and protein tyrosine phosphatases, and the receptors that recruit them, is critical for prevention of these disorders. Balanced signaling by inhibitory and activating receptors is now recognized to be an important factor in tuning cell function and inflammatory potential. In this review, we provide an overview of current knowledge of membrane proximal events in signaling by inhibitory/regulatory receptors focusing on structural and functional characteristics of receptors and their effectors Src homology 2 (SH2) domain-containing tyrosine phosphatase 1 and SH2 domain-containing inositol 5-phosphatase-1. We review use of new strategies to identify novel regulatory receptors and effectors. Finally, we discuss complementary actions of paired inhibitory and activating receptors, using Fc gammaRIIA and Fc gammaRIIB regulation human basophil activation as a prototype.
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Affiliation(s)
- Carol T Cady
- Department of Immunology, University of Colorado Denver School of Medicine, Denver, CO, USA
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23
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Pinheiro da Silva F, Aloulou M, Benhamou M, Monteiro RC. Inhibitory ITAMs: a matter of life and death. Trends Immunol 2008; 29:366-73. [PMID: 18602341 DOI: 10.1016/j.it.2008.05.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Revised: 05/07/2008] [Accepted: 05/20/2008] [Indexed: 12/19/2022]
Abstract
The balance between activating and inhibitory signals is essential to control immune responses to microorganisms. Innate and adaptive immune responses are regulated by receptors that signal through either an immunoreceptor tyrosine-based activation motif (ITAM) or an immunoreceptor tyrosine-based inhibitory motif (ITIM). When clustered, these motifs are, respectively, responsible for activating and inhibitory signals. Recently, the concept of inhibitory ITAM (ITAM(i)) has emerged as a new means to negatively control the immune response. In this Opinion, we will discuss the ability of Escherichia coli to evade the immune system by eliciting ITAM(i) function through FcgammaRIII (CD16) on phagocytes leading to uncontrolled systemic infection and sepsis. Elucidating such mechanisms will open opportunities for specific therapeutic manipulation of ITAM(i)-based signaling pathways.
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24
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Korzeniowski M, Shakor ABA, Makowska A, Drzewiecka A, Bielawska A, Kwiatkowska K, Sobota A. FcγRII Activation Induces Cell Surface Ceramide Production which Participates in the Assembly of the Receptor Signaling Complex. Cell Physiol Biochem 2008; 20:347-56. [PMID: 17762163 DOI: 10.1159/000107520] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2007] [Indexed: 12/12/2022] Open
Abstract
We studied an involvement of various cellular ceramide pools in signaling of immunoreceptor Fc gamma II (Fc gamma RII). The cell surface ceramide level was assessed by a technique based on binding of ceramide probes to intact cells. Total cellular ceramide was estimated by radioactive measurements. The activity of sphingomyelinases was measured by NBD-ceramide release while immunoprecipitation and immunoblotting were applied to analyze protein tyrosine phosphorylation. A complex pattern of protein phosphorylation was found to accompany Fc gamma RII activation and the phosphorylation was either diminished by imipramine or increased by B13, modulators of acid sphingomyelinase and acid ceramidase activity. The effects of the drugs on the phosphorylation of Fc gamma RII and NTAL were prominent and correlated with a reduction of the cell surface ceramide production by imipramine and an augmentation of the ceramide generation by B13. The ceramide generation followed activation of acid sphingomyelinase and preceded that of neutral sphingomyelinase. The level of cell surface ceramide was additionally elevated by exogenous bacterial sphingomyelinase, but only at later stages of the receptor activation. The total mass of ceramide was diminished in the course of receptor activation pointing to an engagement of enzymes metabolizing ceramide. The data indicate that Fc gamma RII activates enzymes of the sphingomyelin cycle which affect various sphingomyelin/ceramide pools in a cell.
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Affiliation(s)
- Marek Korzeniowski
- The Nencki Institute of Experimental Biology, Department of Cell Biology, Warsaw, Poland
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25
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Canetti C, Serezani CH, Atrasz RG, White ES, Aronoff DM, Peters-Golden M. Activation of phosphatase and tensin homolog on chromosome 10 mediates the inhibition of FcgammaR phagocytosis by prostaglandin E2 in alveolar macrophages. THE JOURNAL OF IMMUNOLOGY 2008; 179:8350-6. [PMID: 18056380 DOI: 10.4049/jimmunol.179.12.8350] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PGE2 has important inhibitory effects on the macrophage host defense functions of phagocytosis and killing, yet the molecular mechanisms involved remain to be fully elucidated. PGE2 causes an elevation of cAMP in alveolar macrophages (AMs), which in turn activates the cAMP effector targets, protein kinase A and the exchange protein activated by cAMP (Epac)-1. We now report that FcgammaR-induced PI3K/Akt and ERK-1/2 activation are inhibited by PGE2 in AMs. By specifically inhibiting the phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in AMs, we attenuated the inhibitory effects of both PGE2 and a specific Epac-1 agonist (8-pCPT-2'-O-Me-cAMP) on FcgammaR-mediated phagocytosis and Akt/ERK-1/2 activation; PTEN inhibition also decreased PGE2-induced suppression of bacterial killing by AMs. Moreover, PGE2 and the Epac-1 agonist induced an increase in PTEN lipid phosphatase activity, and this was associated with decreased tyrosine phosphorylation on PTEN-a mechanism known to regulate PTEN activity. Using a pharmacological approach, we demonstrated a role for Src homology 2-containing protein tyrosine phosphatase-1 in the PGE2-induced tyrosine dephosphorylation of PTEN. Collectively, these data reveal that PGE2, via Epac-1 activation, enhances SHP-1 activity, resulting in increased PTEN activity. We suggest that this mechanism contributes to the ability of PGE2 to inhibit PI3K-dependent innate immune signaling in primary macrophages.
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Affiliation(s)
- Claudio Canetti
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Health System, Ann Arbor 48109, USA
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26
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Butchar JP, Rajaram MVS, Ganesan LP, Parsa KVL, Clay CD, Schlesinger LS, Tridandapani S. Francisella tularensis induces IL-23 production in human monocytes. THE JOURNAL OF IMMUNOLOGY 2007; 178:4445-54. [PMID: 17372002 DOI: 10.4049/jimmunol.178.7.4445] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Francisella tularensis, the causative agent of tularemia, is phagocytosed by immune cells such as monocytes and macrophages. Instead of being destroyed in the phagolysosome, the bacterium escapes the phagosome and replicates within the host cytosol. Recent studies indicate that phagosomal escape may have a major impact on the nature of the inflammatory cytokine response to infection. To better understand the host cell response to Francisella infection, we exposed human peripheral blood monocytes to Francisella novicida and analyzed transcriptional changes using high-density oligonucleotide microarrays. Results showed a nearly 300-fold up-regulation of transcripts for the p19 subunit of IL-23, and a nearly 18-fold up-regulation for the p40 subunit of IL-12. IL-23 is formed by the heterodimerization of p19 and p40, and is an important cytokine of the innate immune response. Up-regulation of p19 and p40 was confirmed at the protein level by Western blotting and ELISA analyses, and was found to be largely dependent on PI3K and NF-kappaB activity. Studies using medium from infected monocytes with or without a p19 blocking Ab showed that the secreted IL-23 induced IFN-gamma production from NK cells, suggesting a potential biologically important role for IL-23 in host defense. Finally, infection of human monocytes by the highly virulent Francisella SCHU S4 strain likewise led to IL-23 production, suggesting that the IL-23 response may be relevant during tularemia.
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Affiliation(s)
- Jonathan P Butchar
- Department of Internal Medicine, Division of Infectious Diseases, Ohio State University, 473 West 12th Avenue, Columbus, OH 43210, USA
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27
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Underhill DM, Goodridge HS. The many faces of ITAMs. Trends Immunol 2007; 28:66-73. [PMID: 17197236 DOI: 10.1016/j.it.2006.12.004] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Revised: 11/23/2006] [Accepted: 12/18/2006] [Indexed: 11/17/2022]
Abstract
Innate and adaptive immune responses are regulated by receptors that signal through immunoreceptor tyrosine-based activation motifs (ITAMs). The molecular basis of ITAM signaling has been extensively characterized and serves as a model for receptor-mediated signal transduction. Src family kinases typically phosphorylate ITAMs on dual tyrosines, which enable recruitment and activation of Syk family kinases through binding to dual SH2 domains on these kinases. Examples of ITAM-based signaling that do not conform precisely to the standard model are becoming increasingly common. ITAMs that suppress signaling under specific conditions and activate under others have been described, as have ITAM-like signaling mechanisms using nonstandard sequence motifs. Elucidating the diversity of ITAM-based signaling mechanisms will clarify how activating signals generated by ITAMs are tightly regulated and will open opportunities for specific therapeutic manipulation of ITAM-based signaling pathways.
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Affiliation(s)
- David M Underhill
- Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.
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28
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Rajaram MVS, Ganesan LP, Parsa KVL, Butchar JP, Gunn JS, Tridandapani S. Akt/Protein kinase B modulates macrophage inflammatory response to Francisella infection and confers a survival advantage in mice. THE JOURNAL OF IMMUNOLOGY 2006; 177:6317-24. [PMID: 17056562 DOI: 10.4049/jimmunol.177.9.6317] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The Gram-negative bacterium Francisella novicida infects primarily monocytes/macrophages and is highly virulent in mice. Macrophages respond by producing inflammatory cytokines that confer immunity against the infection. However, the molecular details of host cell response to Francisella infection are poorly understood. In this study, we demonstrate that F. novicida infection of murine macrophages induces the activation of Akt. Inhibition of Akt significantly decreases proinflammatory cytokine production in infected macrophages, whereas production of the anti-inflammatory cytokine IL-10 is enhanced. Analysis of the mechanism of Akt influence on cytokine response demonstrated that Akt promotes NF-kappaB activation. We have extended these findings to show that Akt activation may be regulated by bacterial genes associated with phagosomal escape. Infection with mglA mutants of F. novicida elicited sustained activation of Akt in comparison to cells infected with wild-type F. novicida. Concomitantly, there was significantly higher proinflammatory cytokine production and lower IL-10 production in cells infected with the mglA mutant. Finally, transgenic animals expressing constitutively active Akt displayed a survival advantage over their wild-type littermates when challenged with lethal doses of F. novicida. Together, these observations indicate that Akt promotes proinflammatory cytokine production by F. novicida-infected macrophages through its influence on NF-kappaB, thereby contributing to immunity against F. novicida infection.
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Affiliation(s)
- Murugesan V S Rajaram
- Dorothy M. Davis Heart and Lung Research Institute, 473 West 12th Avenue, Columbus, OH 43210, USA
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29
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Joshi T, Butchar JP, Tridandapani S. Fcgamma receptor signaling in phagocytes. Int J Hematol 2006; 84:210-216. [PMID: 17050193 DOI: 10.1532/ijh97.06140] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Accepted: 07/05/2006] [Indexed: 01/16/2023]
Abstract
Fcgamma receptors are among the best-studied phagocytic receptors. The key features of Fcgamma receptor-mediated phagocytosis include phagocytic cup formation by extensive actin cytoskeletal rearrangements, particle engulfment, and the release of proinflammatory mediators such as cytokines and reactive oxygen species. These events are elegantly regulated by the simultaneous engagement of activating and inhibitory Fcgamma receptors and by intracellular signaling molecules. Extensive studies in the past several years have defined the molecular mechanisms of the phagocytic process. The purpose of this review is to revisit some of the well-established signaling pathways as well as to summarize the new findings in this field.
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Affiliation(s)
- Trupti Joshi
- Department of Internal Medicine, Dorothy M. Davis Heart and Lung Research Institute and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA
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30
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Saxon A, Zhu D, Zhang K, Allen LC, Kepley CL. Genetically engineered negative signaling molecules in the immunomodulation of allergic diseases. Curr Opin Allergy Clin Immunol 2006; 4:563-8. [PMID: 15640700 DOI: 10.1097/00130832-200412000-00015] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW This review summarizes current knowledge regarding the control of human mast cell and basophil signaling and recent developments using a new therapeutic platform consisting of a human bifunctional gamma and epsilon heavy chain (Fc gamma-Fc epsilon) protein to inhibit allergic reactivity. RECENT FINDINGS Crosslinking of Fc gamma RIIb to Fc epsilon RI on human mast cells and basophils by a genetically engineered Fc gamma-Fc epsilon protein (GE2) leads to the inhibition of mediator release upon Fc epsilon RI challenge. GE2 protein was shown to inhibit cord blood-derived mast cell and peripheral blood basophil mediator release in vitro in a dose-dependent fashion, including inhibition of human IgE reactivity to cat. IgE-driven mediator release from lung tissue was also inhibited by GE2. The mechanism of inhibition in mast cells included alterations in IgE-mediated Ca mobilization, spleen tyrosine kinase phosphorylation and the formation of downstream of kinase-growth factor receptor-bound protein 2-SH2 domain-containing inositol 5-phosphatase (dok-grb2-SHIP) complexes. Proallergic effects of Langerhan's like dendritic cells and B-cell IgE switching were also inhibited by GE2. In vivo, GE2 was shown to block passive cutaneous anaphylaxis driven by human IgE in mice expressing the human Fc epsilon RI and inhibit skin test reactivity to dust mite antigen in a dose-dependent manner in rhesus monkeys. SUMMARY The balance between positive and negative signaling controls mast cell and basophil reactivity, which is critical in the expression of human allergic diseases. This approach using a human Fc gamma-Fc epsilon fusion protein to co-aggregate Fc epsilon RI with the Fc gamma RII holds promise as a new therapeutic platform for the immunomodulation of allergic diseases and potentially other mast cell/basophil-dependent disease states.
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Affiliation(s)
- Andrew Saxon
- The Hart and Louise Lyon Laboratory, Division of Clinical Immunology/Allergy, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1680, USA.
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31
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Barrow AD, Trowsdale J. You say ITAM and I say ITIM, let's call the whole thing off: the ambiguity of immunoreceptor signalling. Eur J Immunol 2006; 36:1646-53. [PMID: 16783855 DOI: 10.1002/eji.200636195] [Citation(s) in RCA: 192] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Paradigms of protein tyrosine kinase (PTK)-mediated immunoreceptor signalling have developed largely from studies of molecules containing immunoreceptor tyrosine-based activation motifs (ITAM) and immunoreceptor tyrosine-based inhibition motifs (ITIM). In some circumstances, ITAM can mediate inhibition and ITIM can propagate activation signals. In addition to classical immune cells, some ITAM- and ITIM-encoding proteins are more widely expressed and are crucial to the development of haemopoietic cells, like osteoclasts and natural killer cells, as well as tissues such as bone and brain. Closer analysis of activating proteins reveals that some potentially encode ITIM within an ITAM. These 'closet' ITIM could, under conditions of partial ITAM phosphorylation, mediate inhibitory signalling.
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Affiliation(s)
- Alexander David Barrow
- Cambridge Institute for Medical Research, Wellcome Trust/Medical Research Council building, Cambridge, UK.
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32
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Rönnblom L, Eloranta ML, Alm GV. The type I interferon system in systemic lupus erythematosus. ACTA ACUST UNITED AC 2006; 54:408-20. [PMID: 16447217 DOI: 10.1002/art.21571] [Citation(s) in RCA: 247] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Lars Rönnblom
- Department of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden.
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33
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Abstract
Cells of the immune system possess many multisubunit receptors that are composed of a ligand-binding subunit associated with distinct signaling adaptors containing one or more immunoreceptor tyrosine-based activation motifs (ITAMs). These receptors include the T cell receptor, the B cell receptor, and many Fc receptors, as well as families of activating receptors on myeloid and natural killer cells. Receptors that associate with ITAM-containing adaptors classically have been viewed as transducing activating signals involving phosphorylation of the tyrosines within the ITAM and recruitment of Syk family tyrosine kinases. Receptors associated with ITAM-containing adaptors in myeloid cells have also been implicated in inhibition of cellular activation. Here, we discuss these new negative roles for signaling by receptors that associate with ITAM-bearing adaptors in myeloid and other cell types within the immune system.
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MESH Headings
- Adaptor Proteins, Signal Transducing/deficiency
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/physiology
- Amino Acid Motifs
- Animals
- Antigens, CD/physiology
- Calcium Signaling
- Cell Differentiation
- Cytokines/metabolism
- Enzyme Precursors/physiology
- Humans
- Intracellular Signaling Peptides and Proteins
- Lymphocytes/immunology
- Macrophage Activation
- Mice
- Mice, Knockout
- Mice, Transgenic
- Models, Biological
- Myeloid Cells/immunology
- Phosphorylation
- Phosphotyrosine/physiology
- Protein Processing, Post-Translational/physiology
- Protein Tyrosine Phosphatases/physiology
- Protein-Tyrosine Kinases/physiology
- Receptors, Antigen, B-Cell/chemistry
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, T-Cell/chemistry
- Receptors, Antigen, T-Cell/immunology
- Receptors, Fc/chemistry
- Receptors, Fc/immunology
- Receptors, Fc/physiology
- Receptors, IgG/physiology
- Receptors, Immunologic/chemistry
- Receptors, Immunologic/physiology
- Signal Transduction/physiology
- Syk Kinase
- T-Lymphocytes/cytology
- T-Lymphocytes/immunology
- ZAP-70 Protein-Tyrosine Kinase/physiology
- src Homology Domains
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Affiliation(s)
- Jessica A Hamerman
- Department of Microbiology and Immunology, Cancer Research Institute, University of California, Box 0414, HSE1001, San Francisco, CA 94143-0414, USA
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34
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Abstract
Cell activation results from the transient displacement of an active balance between positive and negative signaling. This displacement depends in part on the engagement of cell surface receptors by extracellular ligands. Among these are receptors for the Fc portion of immunoglobulins (FcRs). FcRs are widely expressed by cells of hematopoietic origin. When binding antibodies, FcRs provide these cells with immunoreceptors capable of triggering numerous biological responses in response to a specific antigen. FcR-dependent cell activation is regulated by negative signals which are generated together with positive signals within signalosomes that form upon FcR engagement. Many molecules involved in positive signaling, including the FcRbeta subunit, the src kinase lyn, the cytosolic adapter Grb2, and the transmembrane adapters LAT and NTAL, are indeed also involved in negative signaling. A major player in negative regulation of FcR signaling is the inositol 5-phosphatase SHIP1. Several layers of negative regulation operate sequentially as FcRs are engaged by extracellular ligands with an increasing valency. A background protein tyrosine phosphatase-dependent negative regulation maintains cells in a "resting" state. SHIP1-dependent negative regulation can be detected as soon as high-affinity FcRs are occupied by antibodies in the absence of antigen. It increases when activating FcRs are engaged by multivalent ligands and, further, when FcR aggregation increases, accounting for the bell-shaped dose-response curve observed in excess of ligand. Finally, F-actin skeleton-associated high-molecular weight SHIP1, recruited to phosphorylated ITIMs, concentrates in signaling complexes when activating FcRs are coengaged with inhibitory FcRs by immune complexes. Based on these data, activating and inhibitory FcRs could be used for new therapeutic approaches to immune disorders.
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Affiliation(s)
- Marc Daëron
- Unité d'Allergologie Moléculaire et Cellulaire, Département d'Immunologie, Institut Pasteur, Paris, France
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35
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Gamberale R, Fernández-Calotti P, Sanjurjo J, Arrossagaray G, Avalos JS, Geffner J, Giordano M. Signaling capacity of FcγRII isoforms in B-CLL cells. Leuk Res 2005; 29:1277-84. [PMID: 15908001 DOI: 10.1016/j.leukres.2005.04.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2005] [Indexed: 11/17/2022]
Abstract
Two main isoforms of Fcgamma receptor II (CD 32) have been described in humans: activatory FcgammaRIIA and inhibitory FcgammaRIIB. We have previously reported that B cells from a subset of chronic lymphocytic leukemia (B-CLL) patients express not only FcgammaRIIB, as normal B lymphocytes, but also the myeloid FcgammaRIIA. The aim of this study was to evaluate the signaling capacity of both FcgammaRII isoforms in B-CLL cells. We found that FcgammaRIIA expressed by leukemic cells failed to induce Ca(2+) mobilization or protein tyrosine phosphorylation, suggesting that the receptor is not functional. By contrast, FcgammaRIIB effectively diminished BCR-triggered ERK 1 phosphorylation, which indicates that it is able to transduce inhibitory signals in B-CLL cells. Moreover, we found that FcgammaRIIB homoaggregation in either B-CLL or non-malignant tonsillar B cells did not result in apoptosis as was reported for murine B splenocytes. Together, these results show that FcgammaRIIB, but not FcgammaRIIA is biologically active in B-CLL cells and might influence leukemic cell physiology in vivo.
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Affiliation(s)
- Romina Gamberale
- Laboratorio de Inmunología, Instituto de Investigaciones Hematológicas, Academia Nacional de Medicina, Pacheco de Melo 3081, 1425 Buenos Aires, Argentina.
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36
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Ai J, Maturu A, Johnson W, Wang Y, Marsh CB, Tridandapani S. The inositol phosphatase SHIP-2 down-regulates FcgammaR-mediated phagocytosis in murine macrophages independently of SHIP-1. Blood 2005; 107:813-20. [PMID: 16179375 PMCID: PMC1895625 DOI: 10.1182/blood-2005-05-1841] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
FcgammaR-mediated phagocytosis of IgG-coated particles is a complex process involving the activation of multiple signaling enzymes and is regulated by the inositol phosphatases PTEN (phosphatase and tensin homolog deleted on chromosome 10) and SHIP-1 (Src homology [SH2] domain-containing inositol phosphatase). In a recent study we have demonstrated that SHIP-2, an inositol phosphatase with high-level homology to SHIP-1, is involved in FcgammaR signaling. However, it is not known whether SHIP-2 plays a role in modulating phagocytosis. In this study we have analyzed the role of SHIP-2 in FcgammaR-mediated phagocytosis using independent cell models that allow for manipulation of SHIP-2 function without influencing the highly homologous SHIP-1. We present evidence that SHIP-2 translocates to the site of phagocytosis and down-regulates FcgammaR-mediated phagocytosis. Our data indicate that SHIP-2 must contain both the N-terminal SH2 domain and the C-terminal proline-rich domain to mediate its inhibitory effect. The effect of SHIP-2 is independent of SHIP-1, as overexpression of dominant-negative SHIP-2 in SHIP-1-deficient primary macrophages resulted in enhanced phagocytic efficiency. Likewise, specific knockdown of SHIP-2 expression using siRNA resulted in enhanced phagocytosis. Finally, analysis of the molecular mechanism of SHIP-2 down-regulation of phagocytosis revealed that SHIP-2 down-regulates upstream activation of Rac. Thus, we conclude that SHIP-2 is a novel negative regulator of FcgammaR-mediated phagocytosis independent of SHIP-1.
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Affiliation(s)
- Jing Ai
- Molecular, Cellular, and Developmental Biology Program, The Ohio State University, USA
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37
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Hallal-Calleros C, Agramonte-Hevia J, Garay-Canales C, Oliver JM, Guerra-Araiza C, Heras D, Camacho-Arroyo I, Soto-Cruz I, Ortega E. Syk and Lyn phosphorylation induced by FcγRI and FγRII crosslinking is determined by the differentiation state of U-937 monocytic cells. Immunol Lett 2005; 99:169-79. [PMID: 16009267 DOI: 10.1016/j.imlet.2005.02.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2004] [Revised: 12/16/2004] [Accepted: 02/15/2005] [Indexed: 10/25/2022]
Abstract
Fcgamma receptor (FcgammaR)-mediated phagocytosis by mononuclear phagocytes is an essential function in host defense. This process is initiated by crosslinking of membrane FcgammaRs, which induces phosphorylation and activation of Src and Syk tyrosine kinases. Activation of these enzymes is essential for initiating the biochemical cascade that results in the cytoskeletal and membrane changes involved in phagocytosis. Phagocytic capacity and other effector functions of mononuclear phagocytes change during differentiation/maturation of these cells. This is a complex process governed by different soluble and micro-environmental factors, giving rise to populations of cells with distinct phenotypic characteristics. Several agents, including calcitriol, have been shown to induce in vitro differentiation-related phenotypic changes in monocytic cell lines. In this paper, we characterized the changes in the initial biochemical signals associated with the increase in FcgammaR-mediated phagocytosis induced by calcitriol in monocytic U-937 cells. The 10-fold increase in phagocytic capacity is not accompanied by an increase in FcgammaR expression. However, the phosphorylation levels of Lyn and Syk after FcgammaRI or FcgammaRII crosslinking are increased after calcitriol treatment. Our results suggest that signaling induced by FcgammaR in mononuclear phagocytes is not only dependent on the quantity of FcgammaRs aggregated by a stimulus, but it is highly dependent on the cell's differentiation state.
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Affiliation(s)
- Claudia Hallal-Calleros
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México - UNAM, D.F
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38
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Pasquier B, Launay P, Kanamaru Y, Moura IC, Pfirsch S, Ruffié C, Hénin D, Benhamou M, Pretolani M, Blank U, Monteiro RC. Identification of FcalphaRI as an inhibitory receptor that controls inflammation: dual role of FcRgamma ITAM. Immunity 2005; 22:31-42. [PMID: 15664157 DOI: 10.1016/j.immuni.2004.11.017] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2004] [Revised: 11/08/2004] [Accepted: 11/10/2004] [Indexed: 11/19/2022]
Abstract
Serum IgA is considered a discrete housekeeper of the immune system with multiple anti-inflammatory functions, whereas IgA-immune complexes mediate inflammatory responses. Here, we identify FcalphaRI as a molecular device that determines the nature of IgA responses. In the absence of sustained aggregation, receptor targeting by serum IgA or anti-FcalphaRI Fab inhibits activating responses of heterologous FcgammaR or FcepsilonRI. The inhibitory mechanism involves recruitment of tyrosine phosphatase SHP-1 to FcalphaRI and impairment of Syk, LAT, and ERK phosphorylation induced by FcepsilonRI engagement. SHP-1 recruitment is dependent on ERK. Conversely, sustained aggregation of FcalphaRI by multimeric ligands stimulates cell activation by recruiting high amounts of Syk and aborting SHP-1 binding. Both types of signals require the FcRgamma-ITAM motif. Anti-FcalphaRI Fab treatment suppresses manifestations of allergic asthma in FcalphaRI transgenic mice. These findings redefine FcalphaRI as a bifunctional inhibitory/activating receptor of the immune system that mediates both anti- and proinflammatory functions of IgA.
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Affiliation(s)
- Benoit Pasquier
- INSERM U699, Bichat Medical School, 16 rue Henri Huchard, 75870 Paris Cedex 18, France
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39
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Swanson JA, Hoppe AD. The coordination of signaling during Fc receptor-mediated phagocytosis. J Leukoc Biol 2004; 76:1093-103. [PMID: 15466916 DOI: 10.1189/jlb.0804439] [Citation(s) in RCA: 224] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Phagocytosis by macrophages can be initiated by Fcgamma receptors (FcR) in membranes that bind to Fc regions of immunoglobulin G (IgG). Activated FcR transduce signals to cytoplasm, which regulate the internalization of IgG-coated particles into plasma membrane-derived vacuoles, phagosomes. Particles internalized by phagocytosis are much larger than FcR, which prompts questions of if and how the receptors are coordinated with each other. FcR-mediated signal transduction entails recruitment of proteins from cytoplasm to the receptor, largely via protein phosphorylation. These FcR signaling complexes then activate proteins that regulate actin, myosin, membrane fusion, and the production of reactive oxygen intermediates. Recent fluorescence microscopic studies of phagocytosis in macrophages indicate that signaling by FcR occurs as a sequence of distinct stages, evident in the spatial and temporal patterns of phosphoinositides, protein kinase C, and Rho-family GTPase activation on forming phagosomes. The coordination of these stages may be regulated by lipids or lipid-anchored proteins, which diffuse away from FcR complexes. Lateral diffusion of FcR-derived signals could integrate FcR-dependent responses over large areas of membrane in the forming phagosome.
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Affiliation(s)
- Joel A Swanson
- University of Michigan Medical School, 1335 Catherine Street, Med Sci II, Rm. 5608, Ann Arbor, MI 48109-0620, USA.
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40
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Cao X, Wei G, Fang H, Guo J, Weinstein M, Marsh CB, Ostrowski MC, Tridandapani S. The inositol 3-phosphatase PTEN negatively regulates Fc gamma receptor signaling, but supports Toll-like receptor 4 signaling in murine peritoneal macrophages. THE JOURNAL OF IMMUNOLOGY 2004; 172:4851-7. [PMID: 15067063 DOI: 10.4049/jimmunol.172.8.4851] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Fc gamma R clustering in macrophages activates signaling events that result in phagocytosis. Phagocytosis is accompanied by the generation harmful byproducts such as reactive oxygen radicals and production of inflammatory cytokines, which mandate that the phagocytic process be subject to a tight regulation. The molecular mechanisms involved in this regulation are not fully understood. In this study, we have examined the role of the inositol 3-phosphatase and tensin homologue deleted on chromosome 10 (PTEN) in Fc gamma R-induced macrophage function. We demonstrate that in ex vivo murine peritoneal macrophages that are deficient in PTEN expression, Fc gamma R-induced Akt and extracellular signal-regulated kinase phosphorylation are enhanced. Notably, PTEN(-/-) macrophages showed constitutively high phosphorylation of Akt. However, PTEN did not seem to influence tyrosine phosphorylation events induced by Fc gamma R clustering. Furthermore, PTEN(-/-) macrophages displayed enhanced phagocytic ability. Likewise, Fc gamma R-induced production of TNF-alpha, IL-6, and IL-10 was significantly elevated in PTEN(-/-) macrophages. Surprisingly, LPS-induced TNF-alpha production was down-regulated in PTEN(-/-) macrophages. Analyzing the molecular events leading to PTEN influence on LPS/Toll-like receptor 4 (TLR4) signaling, we found that LPS-induced activation of mitogen-activated protein kinases is suppressed in PTEN(-/-) cells. Previous reports indicated that LPS-induced mitogen-activated protein kinase activation is down-regulated by phosphatidylinositol 3-kinase through the activation of Akt. Our observation that Akt activation is basally enhanced in PTEN(-/-) cells suggests that PTEN supports TLR4-induced inflammatory responses by suppressing the activation of Akt. Thus, we conclude that PTEN is a negative regulator of Fc gamma R signaling, but a positive regulator of TLR4 signaling. These findings are the first to demonstrate a role for PTEN in Fc gamma R- and TLR4-mediated macrophage inflammatory response.
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Affiliation(s)
- Xianhua Cao
- Biophysics Program, Ohio State University, Columbus, OH 43210, USA
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