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Xu Y, Zhang K, Miao J, Guo N, Fu X, Yang F, Luo X, Jia J, Zheng Z, Zhu P. CD147 regulates the formation and function of immune synapses. Cell Immunol 2024; 401-402:104845. [PMID: 38909549 DOI: 10.1016/j.cellimm.2024.104845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 06/12/2024] [Accepted: 06/17/2024] [Indexed: 06/25/2024]
Abstract
CD147 is a T cell activation-associated molecule which is closely involved in the formation of the immune synapse (IS). However, the precise role of CD147 in T cell activation and IS formation remains unclear. In the present study, we demonstrated that CD147 translocated to the IS upon T cell activation and was primarily distributed in the peripheral super molecular cluster (p-SMAC). The knock down of CD147 expression in T cells, but not in B cells, impaired IS formation. CD147 participated in IS formation between T cells and different types of antigen-presenting cells (APCs), including macrophages and dendritic cells. Ligation of CD147 with its monoclonal antibody (mAb) HAb18 effectively inhibited T cell activation and IL-2 secretion. CD98, a critical molecule interacting with CD147, was distributed in IS in a CD147-dependent way. Phosphorylation levels of T cell receptor (TCR) related molecules, like ZAP-70, ERK, and cJun, were down-regulated by CD147 ligation, which is crucial for the interaction of CD147 and TCR signaling transduction. CD147 is indispensable for the formation of immune synapses and plays an important role in the regulation of its function.
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Affiliation(s)
- Yingming Xu
- Department of Clinical Immunology, Xijing Hospital, and Department of Cell Biology of National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, China.
| | - Kui Zhang
- Department of Clinical Immunology, Xijing Hospital, and Department of Cell Biology of National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, China.
| | - Jinlin Miao
- Department of Clinical Immunology, Xijing Hospital, and Department of Cell Biology of National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, China.
| | - Na Guo
- Department of Clinical Immunology, Xijing Hospital, and Department of Cell Biology of National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, China; Department of Immunology, School of Basic Medicine, Xian Medical University, Xi'an, China.
| | - Xianghui Fu
- Department of Clinical Immunology, Xijing Hospital, and Department of Cell Biology of National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, China.
| | - Fengfan Yang
- Department of Clinical Immunology, Xijing Hospital, and Department of Cell Biology of National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, China.
| | - Xing Luo
- Department of Clinical Immunology, Xijing Hospital, and Department of Cell Biology of National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, China.
| | - Junfeng Jia
- Department of Clinical Immunology, Xijing Hospital, and Department of Cell Biology of National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, China.
| | - Zhaohui Zheng
- Department of Clinical Immunology, Xijing Hospital, and Department of Cell Biology of National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, China.
| | - Ping Zhu
- Department of Clinical Immunology, Xijing Hospital, and Department of Cell Biology of National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, China.
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Assessment of membrane lipid state at the natural killer cell immunological synapse. Methods Cell Biol 2023; 173:77-89. [PMID: 36653087 PMCID: PMC10182816 DOI: 10.1016/bs.mcb.2022.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The plasma membrane is a fluid structure that protects cells as one of their first barriers and actively participates in numerous biological processes in many ways including through distinct membrane sub-regions. For immunological cells, highly organized sub-compartments of plasma membranes are vital for them to sense and react to environmental changes. This includes a varying spectrum of lipid ordering in the plasma membrane which signifies or enables cellular functions. Thus, comprehensive analyses of the plasma membrane can facilitate understanding of important cell biological elements which include insights into immune cells. Here, we describe two methods that can be used to assess membrane lipid state at the natural killer cell immunological synapse via high-resolution live cell imaging techniques.
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Degranulation enhances presynaptic membrane packing, which protects NK cells from perforin-mediated autolysis. PLoS Biol 2021. [DOI: 10.1371/journal.pbio.3001328
expr 949426982 + 863878017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Natural killer (NK) cells kill a target cell by secreting perforin into the lytic immunological synapse, a specialized interface formed between the NK cell and its target. Perforin creates pores in target cell membranes allowing delivery of proapoptotic enzymes. Despite the fact that secreted perforin is in close range to both the NK and target cell membranes, the NK cell typically survives while the target cell does not. How NK cells preferentially avoid death during the secretion of perforin via the degranulation of their perforin-containing organelles (lytic granules) is perplexing. Here, we demonstrate that NK cells are protected from perforin-mediated autolysis by densely packed and highly ordered presynaptic lipid membranes, which increase packing upon synapse formation. When treated with 7-ketocholesterol, lipid packing is reduced in NK cells making them susceptible to perforin-mediated lysis after degranulation. Using high-resolution imaging and lipidomics, we identified lytic granules themselves as having endogenously densely packed lipid membranes. During degranulation, lytic granule–cell membrane fusion thereby further augments presynaptic membrane packing, enhancing membrane protection at the specific sites where NK cells would face maximum concentrations of secreted perforin. Additionally, we found that an aggressive breast cancer cell line is perforin resistant and evades NK cell–mediated killing owing to a densely packed postsynaptic membrane. By disrupting membrane packing, these cells were switched to an NK-susceptible state, which could suggest strategies for improving cytotoxic cell-based cancer therapies. Thus, lipid membranes serve an unexpected role in NK cell functionality protecting them from autolysis, while degranulation allows for the inherent lytic granule membrane properties to create local ordered lipid “shields” against self-destruction.
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Li Y, Orange JS. Degranulation enhances presynaptic membrane packing, which protects NK cells from perforin-mediated autolysis. PLoS Biol 2021; 19:e3001328. [PMID: 34343168 PMCID: PMC8330931 DOI: 10.1371/journal.pbio.3001328&set/a 870330320+893642561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Natural killer (NK) cells kill a target cell by secreting perforin into the lytic immunological synapse, a specialized interface formed between the NK cell and its target. Perforin creates pores in target cell membranes allowing delivery of proapoptotic enzymes. Despite the fact that secreted perforin is in close range to both the NK and target cell membranes, the NK cell typically survives while the target cell does not. How NK cells preferentially avoid death during the secretion of perforin via the degranulation of their perforin-containing organelles (lytic granules) is perplexing. Here, we demonstrate that NK cells are protected from perforin-mediated autolysis by densely packed and highly ordered presynaptic lipid membranes, which increase packing upon synapse formation. When treated with 7-ketocholesterol, lipid packing is reduced in NK cells making them susceptible to perforin-mediated lysis after degranulation. Using high-resolution imaging and lipidomics, we identified lytic granules themselves as having endogenously densely packed lipid membranes. During degranulation, lytic granule-cell membrane fusion thereby further augments presynaptic membrane packing, enhancing membrane protection at the specific sites where NK cells would face maximum concentrations of secreted perforin. Additionally, we found that an aggressive breast cancer cell line is perforin resistant and evades NK cell-mediated killing owing to a densely packed postsynaptic membrane. By disrupting membrane packing, these cells were switched to an NK-susceptible state, which could suggest strategies for improving cytotoxic cell-based cancer therapies. Thus, lipid membranes serve an unexpected role in NK cell functionality protecting them from autolysis, while degranulation allows for the inherent lytic granule membrane properties to create local ordered lipid "shields" against self-destruction.
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Affiliation(s)
- Yu Li
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, United States of America.,Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, New York, United States of America
| | - Jordan S Orange
- Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, New York, United States of America
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5
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Li Y, Orange JS. Degranulation enhances presynaptic membrane packing, which protects NK cells from perforin-mediated autolysis. PLoS Biol 2021; 19:e3001328. [PMID: 34343168 PMCID: PMC8330931 DOI: 10.1371/journal.pbio.3001328] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 06/16/2021] [Indexed: 12/27/2022] Open
Abstract
Natural killer (NK) cells kill a target cell by secreting perforin into the lytic immunological synapse, a specialized interface formed between the NK cell and its target. Perforin creates pores in target cell membranes allowing delivery of proapoptotic enzymes. Despite the fact that secreted perforin is in close range to both the NK and target cell membranes, the NK cell typically survives while the target cell does not. How NK cells preferentially avoid death during the secretion of perforin via the degranulation of their perforin-containing organelles (lytic granules) is perplexing. Here, we demonstrate that NK cells are protected from perforin-mediated autolysis by densely packed and highly ordered presynaptic lipid membranes, which increase packing upon synapse formation. When treated with 7-ketocholesterol, lipid packing is reduced in NK cells making them susceptible to perforin-mediated lysis after degranulation. Using high-resolution imaging and lipidomics, we identified lytic granules themselves as having endogenously densely packed lipid membranes. During degranulation, lytic granule-cell membrane fusion thereby further augments presynaptic membrane packing, enhancing membrane protection at the specific sites where NK cells would face maximum concentrations of secreted perforin. Additionally, we found that an aggressive breast cancer cell line is perforin resistant and evades NK cell-mediated killing owing to a densely packed postsynaptic membrane. By disrupting membrane packing, these cells were switched to an NK-susceptible state, which could suggest strategies for improving cytotoxic cell-based cancer therapies. Thus, lipid membranes serve an unexpected role in NK cell functionality protecting them from autolysis, while degranulation allows for the inherent lytic granule membrane properties to create local ordered lipid "shields" against self-destruction.
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Affiliation(s)
- Yu Li
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, New York, United States of America
| | - Jordan S. Orange
- Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, New York, United States of America
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High Cholesterol/Low Cholesterol: Effects in Biological Membranes: A Review. Cell Biochem Biophys 2017; 75:369-385. [PMID: 28417231 DOI: 10.1007/s12013-017-0792-7] [Citation(s) in RCA: 173] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/27/2017] [Indexed: 12/11/2022]
Abstract
Lipid composition determines membrane properties, and cholesterol plays a major role in this determination as it regulates membrane fluidity and permeability, as well as induces the formation of coexisting phases and domains in the membrane. Biological membranes display a very diverse lipid composition, the lateral organization of which plays a crucial role in regulating a variety of membrane functions. We hypothesize that, during biological evolution, membranes with a particular cholesterol content were selected to perform certain functions in the cells of eukaryotic organisms. In this review, we discuss the major membrane properties induced by cholesterol, and their relationship to certain membrane functions.
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Cellular signaling in the aging immune system. Curr Opin Immunol 2014; 29:105-11. [PMID: 24934647 DOI: 10.1016/j.coi.2014.05.007] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/16/2014] [Accepted: 05/19/2014] [Indexed: 12/11/2022]
Abstract
Causes for immunosenescence and inflamm-aging have to be established. Efficient function of the immune system requires homeostatic regulation from receptor recognition of antigenic challenge to cell responses and adaptation to its changing environment. It is reasonable to assume that one of the most important molecular causes of immunosenescence is alteration in the regulation of signaling pathways. Indeed, alterations in feed-forward and negative feedback (inhibitory) signaling have been highlighted in all cells involved in the immune response including short-lived (neutrophils) and long-lived (T lymphocytes) cells. These dysregulations tip the balance in favor of altered (less efficient) function of the immune system. In this review, we summarize our knowledge on signal transduction changes in the aging immune system and propose a unifying mechanism as one of the causes of immunosenescence. Modulation of these pathways with aging represents a major challenge to restore the immune response to functional levels.
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Thayanithy V, Babatunde V, Dickson EL, Wong P, Oh S, Ke X, Barlas A, Fujisawa S, Romin Y, Moreira AL, Downey RJ, Steer CJ, Subramanian S, Manova-Todorova K, Moore MAS, Lou E. Tumor exosomes induce tunneling nanotubes in lipid raft-enriched regions of human mesothelioma cells. Exp Cell Res 2014; 323:178-188. [PMID: 24468420 DOI: 10.1016/j.yexcr.2014.01.014] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 01/13/2014] [Accepted: 01/15/2014] [Indexed: 01/20/2023]
Abstract
Tunneling nanotubes (TnTs) are long, non-adherent, actin-based cellular extensions that act as conduits for transport of cellular cargo between connected cells. The mechanisms of nanotube formation and the effects of the tumor microenvironment and cellular signals on TnT formation are unknown. In the present study, we explored exosomes as potential mediators of TnT formation in mesothelioma and the potential relationship of lipid rafts to TnT formation. Mesothelioma cells co-cultured with exogenous mesothelioma-derived exosomes formed more TnTs than cells cultured without exosomes within 24-48 h; and this effect was most prominent in media conditions (low-serum, hyperglycemic medium) that support TnT formation (1.3-1.9-fold difference). Fluorescence and electron microscopy confirmed the purity of isolated exosomes and revealed that they localized predominantly at the base of and within TnTs, in addition to the extracellular environment. Time-lapse microscopic imaging demonstrated uptake of tumor exosomes by TnTs, which facilitated intercellular transfer of these exosomes between connected cells. Mesothelioma cells connected via TnTs were also significantly enriched for lipid rafts at nearly a 2-fold higher number compared with cells not connected by TnTs. Our findings provide supportive evidence of exosomes as potential chemotactic stimuli for TnT formation, and also lipid raft formation as a potential biomarker for TnT-forming cells.
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Affiliation(s)
- Venugopal Thayanithy
- Department of Medicine, Division of Hematology, Oncology and Transplantation, University of Minnesota, Minneapolis, MN 55455, USA
| | - Victor Babatunde
- Moore Laboratory, Department of Cell Biology, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | - Elizabeth L Dickson
- Department of Obstetrics & Gynecology, Division of Gynecologic Oncology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Phillip Wong
- Department of Medicine, Division of Hematology, Oncology and Transplantation, University of Minnesota, Minneapolis, MN 55455, USA
| | - Sanghoon Oh
- Molecular Cytology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | - Xu Ke
- Molecular Cytology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | - Afsar Barlas
- Molecular Cytology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | - Sho Fujisawa
- Molecular Cytology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | - Yevgeniy Romin
- Molecular Cytology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | - André L Moreira
- Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | - Robert J Downey
- Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | - Clifford J Steer
- Departments of Medicine and Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | | | | | - Malcolm A S Moore
- Moore Laboratory, Department of Cell Biology, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | - Emil Lou
- Department of Medicine, Division of Hematology, Oncology and Transplantation, University of Minnesota, Minneapolis, MN 55455, USA.
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Fulop T, Le Page A, Garneau H, Azimi N, Baehl S, Dupuis G, Pawelec G, Larbi A. Aging, immunosenescence and membrane rafts: the lipid connection. LONGEVITY & HEALTHSPAN 2012; 1:6. [PMID: 24764511 PMCID: PMC3886260 DOI: 10.1186/2046-2395-1-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 07/13/2012] [Indexed: 11/10/2022]
Abstract
The decreased efficiency of immune responses in older people is partly a consequence of alterations in T lymphocyte functions caused by modifications in the early events of signal transduction. Several alterations in the signaling pathways of T lymphocytes have been described in older humans and animals. A unifying cause could be modifications in the physicochemical properties of the plasma membrane resulting from changes in its lipid composition and the distribution and function of lipid rafts (LR). The latter serve to assemble the initial components of the signaling cascade. Accumulating data suggest that the function of plasma membrane LR is altered with aging; we hypothesize that this would significantly contribute to immune dysregulation. The role of aging and cholesterol in LR functions in T lymphocytes is reviewed and discussed here.
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Affiliation(s)
- Tamas Fulop
- Department of Medicine, Research Center on Aging, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, 3001 12th Avenue North, Sherbrooke, Qc, J1H 5N4, Canada ; Research Center on Aging, University of Sherbrooke, 1036, rue Belvedere Sud, Sherbrooke, Qc, J1H 4C4, Canada
| | - Aurélie Le Page
- Department of Medicine, Research Center on Aging, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, 3001 12th Avenue North, Sherbrooke, Qc, J1H 5N4, Canada
| | - Hugo Garneau
- Department of Medicine, Research Center on Aging, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, 3001 12th Avenue North, Sherbrooke, Qc, J1H 5N4, Canada
| | - Naheed Azimi
- Department of Medicine, Research Center on Aging, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, 3001 12th Avenue North, Sherbrooke, Qc, J1H 5N4, Canada
| | - Sarra Baehl
- Department of Medicine, Research Center on Aging, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, 3001 12th Avenue North, Sherbrooke, Qc, J1H 5N4, Canada
| | - Gilles Dupuis
- Department of Biochemistry, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, 3001 12th Avenue North, Sherbrooke, Qc, J1H 5N4, Canada
| | - Graham Pawelec
- Center for Medical Research, Tübingen Aging and Tumor Immunology Group, University of Tübingen, Waldhörnlestrasse 22, Tübingen, D-72072, Germany
| | - Anis Larbi
- Singapore Immunology Network (SIgN), Immunos Building/Biopolis, Agency for Science Technology and Research (ASTAR), 8A Biomedical Grove, Singapore, 138648, Singapore
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Gonnord P, Blouin CM, Lamaze C. Membrane trafficking and signaling: two sides of the same coin. Semin Cell Dev Biol 2011; 23:154-64. [PMID: 22085846 DOI: 10.1016/j.semcdb.2011.11.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 11/02/2011] [Indexed: 02/07/2023]
Abstract
Recent findings on clathrin-dependent and non clathrin-dependent endocytic routes are currently changing our classical view of endocytosis. Originally seen as a way for the cell to internalize membrane, receptors or various soluble molecules, this process is in fact directly linked to complex signaling pathways. Here, we review new insights in endocytosis and present latest development in imaging techniques that allow us to visualize and follow the dynamics of membrane-associated signaling events at the plasma membrane and other intracellular compartments. The immune synapse is taken as an illustration of the importance of membrane reorganization and proteins clustering to initiate and maintain signaling. Future challenges include understanding the crosslink between traffic and signaling and how all compartmentalized signals are integrated inside the cell at a higher level.
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Affiliation(s)
- Pauline Gonnord
- Laboratory of Cellular and Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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Pata S, Otáhal P, Brdička T, Laopajon W, Mahasongkram K, Kasinrerk W. Association of CD99 short and long forms with MHC class I, MHC class II and tetraspanin CD81 and recruitment into immunological synapses. BMC Res Notes 2011; 4:293. [PMID: 21838920 PMCID: PMC3170336 DOI: 10.1186/1756-0500-4-293] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 08/13/2011] [Indexed: 11/10/2022] Open
Abstract
Background CD99, a leukocyte surface glycoprotein, is broadly expressed in many cell types. On the cell surface, CD99 is expressed as two distinct isoforms, a long form and a short form. CD99 has been demonstrated to play a key role in several biological processes, including the regulation of T cell activation. However, the molecular mechanisms by which CD99 participates in such processes are unclear. As CD99 contains a short cytoplasmic tail, it is unlikely that CD99 itself takes part in its multi-functions. Association of CD99 with other membrane proteins has been suggested to be necessary for exerting its functions. Results In this study, we analyzed the association of CD99 with other cell surface molecules involved in T cell activation. We demonstrate the association of MHC class I, MHC class II and tetraspanin CD81 with CD99 molecules on the cell surface. Association of CD99 with its partners was observed for both isoforms. In addition, we determined that CD99 is a lipid raft-associated membrane protein and is recruited into the immunologic synapse during T cell activation. The implication of CD99 on T cell activation was investigated. Inhibition of anti-CD3 induced T cell proliferation by an anti-CD99 monoclonal antibody was observed. Conclusions We provide evidence that CD99 directly interact and form the complex with the MHC class I and II, and tetraspanin CD81, and is functionally linked to the formation of the immunologic synapse. Upon T cell activation, CD99 engagement can inhibit T cell proliferation. We speculate that the CD99-MHC-CD81 complex is a tetraspanin web that plays an important role in T cell activation.
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Affiliation(s)
- Supansa Pata
- Division of Clinical Immunology, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand.
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Martinez E, Brzostowski JA, Long EO, Gross CC. Cutting edge: NKG2D-dependent cytotoxicity is controlled by ligand distribution in the target cell membrane. THE JOURNAL OF IMMUNOLOGY 2011; 186:5538-42. [PMID: 21464092 DOI: 10.4049/jimmunol.1002254] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Although the importance of membrane microdomains in receptor-mediated activation of lymphocytes has been established, much less is known about the role of receptor ligand distribution on APC and target cells. Detergent-resistant membrane domains, into which GPI-linked proteins partition, are enriched in cholesterol and glycosphingolipids. ULBP1 is a GPI-linked ligand for natural cytotoxicity receptor NKG2D. To investigate how ULBP1 distribution on target cells affects NKG2D-dependent NK cell activation, we fused the extracellular domain of ULBP1 to the transmembrane domain of CD45. Introduction of this transmembrane domain eliminated the association of ULBP1 with the detergent-resistant membrane fraction and caused a significant reduction of cytotoxicity and degranulation by NK cells. Clustering and lateral diffusion of ULBP1 was not affected by changes in the membrane anchor. These results show that the partitioning of receptor ligands in discrete membrane domains of target cells is an important determinant of NK cell activation.
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Affiliation(s)
- Emily Martinez
- Molecular and Cellular Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
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Jo JH, Kwon MS, Choi HO, Oh HM, Kim HJ, Jun CD. Recycling and LFA-1-dependent trafficking of ICAM-1 to the immunological synapse. J Cell Biochem 2011; 111:1125-37. [PMID: 20681010 DOI: 10.1002/jcb.22798] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Little is known about how adhesion molecules on APCs accumulate at immunological synapses. We show here that ICAM-1 on APCs is continuously internalized and rapidly recycled back to the interface after antigen-priming T-cell contact. The internalization rate is high in APCs, including Raji B cells and dendritic cells, but low in endothelial cells. Internalization is significantly reduced by inhibitors of Na(+)/H(+) exchangers (NHEs), suggesting that members of the NHE-family regulate this process. Once internalized, ICAM-1 is co-localized with MHC class II in the polarized recycling compartment. Surprisingly, not only ICAM-1, but also MHC class II, is targeted to the immunological synapse through LFA-1-dependent adhesion. Cytosolic ICAM-1 is highly mobile and forms a tubular structure. Inhibitors of microtubule or actin polymerization can reduce ICAM-1 mobility, and thereby block accumulation at immunological synapses. Membrane ICAM-1 also moves to the T-cell contact zone, presumably through an active, cytoskeleton-dependent mechanism. Collectively, these results demonstrate that ICAM-1 can be transported to the immunological synapse through the recycling compartment. Furthermore, the high-affinity state of LFA-1 on T cells is critical to induce targeted movements of both ICAM-1 and MHC class II to the immunological synapse on APCs.
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Affiliation(s)
- Jae-Hyeok Jo
- School of Life Sciences, Cell Dynamics Research Center, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea
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Van Prooyen N, Andresen V, Gold H, Bialuk I, Pise-Masison C, Franchini G. Hijacking the T-cell communication network by the human T-cell leukemia/lymphoma virus type 1 (HTLV-1) p12 and p8 proteins. Mol Aspects Med 2010; 31:333-43. [PMID: 20673780 DOI: 10.1016/j.mam.2010.07.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 07/22/2010] [Accepted: 07/23/2010] [Indexed: 12/14/2022]
Abstract
The non-structural proteins encoded by the orf-I, II, III, and IV genes of the human T-cell leukemia/lymphoma virus type 1 (HTLV-1) genome, are critical for the modulation of cellular gene expression and T-cell proliferation, the escape from cytotoxic T-cells and natural killer cells, and virus expression. In here, we review the main functions of the HTLV-1 orf-I products. The 12kDa product from orf-I (p12) is proteolytically cleaved within the endoplasmic reticulum (ER) to generate the 8kDa protein (p8). At the steady state, both proteins are expressed at similar levels in transfected T-cells. The p12 protein remains in the ER and cis-Golgi, whereas the p8 protein traffics to the cell surface and is recruited to the immunological synapse. The p12 and the p8 proteins have seemingly opposite effects on T-cells; the ER resident p12, modulates T-cell activation and proliferation, whereas p8 induces T-cell anergy. The p8 protein also increases the formation of cellular conduits, is transferred to neighboring T-cells, and increases virus transmission. The requirement for HTLV-1 infectivity of orf-I is demonstrated by the loss of virus infectivity in macaques exposed to an engineered virus, whereby expression of orf-I was ablated. Altogether the current knowledge demonstrates that the concerted activity of p8 and p12 is essential for the persistence of virus infected cells in the host.
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Affiliation(s)
- Nancy Van Prooyen
- Animal Models and Retroviral Vaccine Section, Vaccine Branch, National Cancer Institute, National Institute of Health, Bethesda, MD 20892-5065, USA
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15
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Hu J, Dang N, Yao H, Li Y, Zhang H, Yang X, Xu J, Bian H, Xing J, Zhu P, Chen Z. Involvement of HAb18G/CD147 in T cell activation and immunological synapse formation. J Cell Mol Med 2010; 14:2132-43. [PMID: 20082657 PMCID: PMC3823004 DOI: 10.1111/j.1582-4934.2010.01012.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
HAb18G/CD147, a glycoprotein of the immunoglobulin super-family (IgSF), is a T cell activation-associated molecule. In this report, we demonstrated that HAb18G/CD147 expression on both activated CD4+ and CD8+ T cells was up-regulated. In vitro cross-linking of T cells with an anti-HAb18G/CD147 monoclonal antibody (mAb) 5A12 inhibited T cells proliferation upon T cell receptor stimulation. Such co-stimulation inhibited T cell proliferation by down-regulating the expression of CD25 and interleukin-2 (IL-2), decreased production of IL-4 but not interferon-γ. Laser confocal imaging analysis indicated that HAb18G/CD147 was recruited to the immunological synapse (IS) during T cell activation; triggering HAb18G/CD147 on activated T cells by anti-HAb18G/CD147 mAb 5A12 strongly dispersed the formation of the IS. Further functional studies showed that the ligation of HAb18G/CD147 with mAb 5A12 decreased the tyrosine phosphorylation and intracellular calcium mobilization levels of T cells. Through docking antibody–antigen interactions, we demonstrated that the function of mAb 5A12 is tightly dependent on its specificity of binding to N-terminal domain I, which plays pivotal role in the oligomerization of HAb18G/CD147. Taken together, we provide evidence that HAb18G/CD147 could act as a co-stimulatory receptor to negatively regulate T cell activation and is functionally linked to the formation of the IS.
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Affiliation(s)
- Jinsong Hu
- State Key Laboratory of Cancer Biology, Cell Engineering Research Centre & Department of Cell Biology, Fourth Military Medical University, Xi'an, People's Republic of China
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16
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Peng W, Martaresche C, Escande-Beillard N, Cedile O, Reynier-Vigouroux A, Boucraut J. Influence of lipid rafts on CD1d presentation by dendritic cells. Mol Membr Biol 2009; 24:475-84. [PMID: 17710651 DOI: 10.1080/09687680701359408] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Our main objective was to analyze the role of lipid rafts in the activation of Valpha-14(-) and Valpha-14(+) T hybridomas by dendritic cells. We showed that activation of Valpha-14(+) hybridomas by dendritic cells or other CD1d-expressing cells was altered by disruption of lipid rafts with the cholesterol chelator MbetaCD. However, CD1d presentation to autoreactive Valpha-14(-) anti-CD1d hybridomas which do not require the endocytic pathway was not altered. Using partitioning of membrane fractions with Brij98 at 37 degrees C, we confirmed that CD1d was enriched in subcellular fractions corresponding to lipid rafts and we describe that alpha-GalCer enhanced CD1d amount in the low density detergent insoluble fraction. We conclude that the membrane environment of CD1d can influence antigen presentation mainly when the endocytic pathway is required. Flow cytometry analysis can provide additional information on lipid rafts in plasma membranes and allows a dynamics follow-up of lipid rafts partitioning. Using this method, we showed that CD1d plasma membrane expression was sensitive to low concentrations of detergent. This may suggest either that CD1d is associated with lipid rafts mainly in intracellular membranes or that its association with the lipid rafts in the plasma membrane is weak.
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Affiliation(s)
- Wei Peng
- Faculté de Médecine de Marseille, NICN, CNRS UMR 6184, Université de la Méditerranée, Marseille, France
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17
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Owada T, Watanabe N, Oki M, Oya Y, Saito Y, Saito T, Iwamoto I, Murphy TL, Murphy KM, Nakajima H. Activation-induced accumulation of B and T lymphocyte attenuator at the immunological synapse in CD4+ T cells. J Leukoc Biol 2009; 87:425-32. [PMID: 19892849 DOI: 10.1189/jlb.0309138] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
BTLA, a recently cloned coreceptor expressed on lymphocytes, negatively regulates cell activation by recruiting SHP-1/SHP-2. However, the mechanisms that regulate the intracellular localization of BTLA and its trafficking to the cell surface in T cells are still unknown. To determine the mechanisms that regulate the expression of BTLA on the surface of T cells, we examined the subcellular localization of BTLA in mouse T cells in a steady state, as well as upon activation by using a confocal laser-scanning microscopy. We found that BTLA was localized mainly in the Golgi apparatus and secretory lysosomes in resting CD4(+) T cells. We also found that intracellular BTLA was translocated to the cell surface and accumulated at the immunological synapse upon TCR stimulation. Furthermore, we found that the BTLA-HVEM interaction was required for the association of BTLA with lipid rafts. These results indicate that the surface expression of BTLA and its accumulation at the immunological synapse are tightly regulated by TCR and HVEM stimulation to deliver efficient inhibitory signals in the regulation of CD4(+) T cell activation.
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Affiliation(s)
- Takayoshi Owada
- Departments of Allergy and Clinical Immunology, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8670, Japan
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18
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Murphy SC, Hiller NL, Harrison T, Lomasney JW, Mohandas N, Haldar K. Lipid rafts and malaria parasite infection of erythrocytes (Review). Mol Membr Biol 2009; 23:81-8. [PMID: 16611583 DOI: 10.1080/09687860500473440] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Infection of human erythrocytes by the malarial parasite, Plasmodium falciparum, results in complex membrane sorting and signaling events in the mature erythrocyte. These events appear to rely heavily on proteins resident in erythrocyte lipid rafts. Over the past five years, we and others have undertaken a comprehensive characterization of major proteins present in erythrocyte detergent-resistant membrane lipid rafts and determined which of these proteins traffic to the host-derived membrane that bounds the intraerythrocytic parasite. The data suggest that raft association is necessary but not sufficient for vacuolar recruitment, and that there is likely a mechanism of active uptake of a subset of erythrocyte detergent-resistant membrane proteins. Of the ten internalized proteins, few have been evaluated for a role in malarial entry. The beta(2)-adrenergic receptor and heterotrimeric G protein G(s) signaling pathway proteins regulate invasion. The implications of these differences are discussed. In addition, the latter finding indicates that erythrocytes possess important signaling pathways. These signaling cascades may have important influences on in vivo malarial infection, as well as on erythrocyte membrane flexibility and adhesiveness in sickle cell anemia. With respect to malarial infection, host signaling components alone are not sufficient to induce formation of the malarial vacuole. Parasite proteins are likely to have a major role in making the intraerythrocytic environment conducive for vacuole formation. Such interactions should be the focus of future efforts to understand malarial infection of erythrocytes since host- and parasite-targeted interventions are urgently needed to combat this terrible disease.
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Affiliation(s)
- Sean C Murphy
- Department of Pathology and Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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19
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Orange JS. Formation and function of the lytic NK-cell immunological synapse. Nat Rev Immunol 2009; 8:713-25. [PMID: 19172692 DOI: 10.1038/nri2381] [Citation(s) in RCA: 425] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The natural killer (NK)-cell immunological synapse is the dynamic interface formed between an NK cell and its target cell. Formation of the NK-cell immunological synapse involves several distinct stages, from the initiation of contact with a target cell to the directed delivery of lytic-granule contents for target-cell lysis. Progression through the individual stages is regulated, and this tight regulation underlies the precision with which NK cells select and kill susceptible target cells (including virally infected cells and cancerous cells) that they encounter during their routine surveillance of the body.
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Affiliation(s)
- Jordan S Orange
- University of Pennsylvania School of Medicine, Joseph Stokes Jr Research Institute of The Children's Hospital of Philadelphia, 3615 Civic Center Boulevard, ARC 1016H, Philadelphia, Pennsylvania 19104, USA.
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20
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Henis YI, Hancock JF, Prior IA. Ras acylation, compartmentalization and signaling nanoclusters (Review). Mol Membr Biol 2008; 26:80-92. [PMID: 19115142 DOI: 10.1080/09687680802649582] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Ras proteins have become paradigms for isoform- and compartment-specific signaling. Recent work has shown that Ras isoforms are differentially distributed within cell surface signaling nanoclusters and on endomembranous compartments. The critical feature regulating Ras protein localization and isoform-specific functions is the C-terminal hypervariable region (HVR). In this review we discuss the differential post-translational modifications and reversible targeting functions of Ras isoform HVR motifs. We describe how compartmentalized Ras signaling has specific functional consequences and how cell surface signaling nanoclusters generate precise signaling outputs.
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Affiliation(s)
- Yoav I Henis
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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21
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Barcia C, Sanderson NSR, Barrett RJ, Wawrowsky K, Kroeger KM, Puntel M, Liu C, Castro MG, Lowenstein PR. T cells' immunological synapses induce polarization of brain astrocytes in vivo and in vitro: a novel astrocyte response mechanism to cellular injury. PLoS One 2008; 3:e2977. [PMID: 18714338 PMCID: PMC2496894 DOI: 10.1371/journal.pone.0002977] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Accepted: 07/17/2008] [Indexed: 12/02/2022] Open
Abstract
Background Astrocytes usually respond to trauma, stroke, or neurodegeneration by undergoing cellular hypertrophy, yet, their response to a specific immune attack by T cells is poorly understood. Effector T cells establish specific contacts with target cells, known as immunological synapses, during clearance of virally infected cells from the brain. Immunological synapses mediate intercellular communication between T cells and target cells, both in vitro and in vivo. How target virally infected astrocytes respond to the formation of immunological synapses established by effector T cells is unknown. Findings Herein we demonstrate that, as a consequence of T cell attack, infected astrocytes undergo dramatic morphological changes. From normally multipolar cells, they become unipolar, extending a major protrusion towards the immunological synapse formed by the effector T cells, and withdrawing most of their finer processes. Thus, target astrocytes become polarized towards the contacting T cells. The MTOC, the organizer of cell polarity, is localized to the base of the protrusion, and Golgi stacks are distributed throughout the protrusion, reaching distally towards the immunological synapse. Thus, rather than causing astrocyte hypertrophy, antiviral T cells cause a major structural reorganization of target virally infected astrocytes. Conclusions Astrocyte polarization, as opposed to hypertrophy, in response to T cell attack may be due to T cells providing a very focused attack, and thus, astrocytes responding in a polarized manner. A similar polarization of Golgi stacks towards contacting T cells was also detected using an in vitro allogeneic model. Thus, different T cells are able to induce polarization of target astrocytes. Polarization of target astrocytes in response to immunological synapses may play an important role in regulating the outcome of the response of astrocytes to attacking effector T cells, whether during antiviral (e.g. infected during HIV, HTLV-1, HSV-1 or LCMV infection), anti-transplant, autoimmune, or anti-tumor immune responses in vivo and in vitro.
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Affiliation(s)
- Carlos Barcia
- Board of Governors' Gene Therapeutics Research Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
- Department of Medicine, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Molecular and Medical Pharmacology, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Nicholas S. R. Sanderson
- Board of Governors' Gene Therapeutics Research Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
- Department of Medicine, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Molecular and Medical Pharmacology, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Robert J. Barrett
- Board of Governors' Gene Therapeutics Research Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
- Department of Medicine, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Molecular and Medical Pharmacology, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Kolja Wawrowsky
- Department of Endocrinology, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Kurt M. Kroeger
- Board of Governors' Gene Therapeutics Research Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
- Department of Medicine, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Molecular and Medical Pharmacology, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Mariana Puntel
- Board of Governors' Gene Therapeutics Research Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
- Department of Medicine, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Molecular and Medical Pharmacology, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Chunyan Liu
- Board of Governors' Gene Therapeutics Research Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
- Department of Medicine, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Molecular and Medical Pharmacology, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Maria G. Castro
- Board of Governors' Gene Therapeutics Research Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
- Department of Medicine, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Molecular and Medical Pharmacology, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Pedro R. Lowenstein
- Board of Governors' Gene Therapeutics Research Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
- Department of Medicine, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Molecular and Medical Pharmacology, The Brain Research Institute, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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22
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Larbi A, Franceschi C, Mazzatti D, Solana R, Wikby A, Pawelec G. Aging of the immune system as a prognostic factor for human longevity. Physiology (Bethesda) 2008; 23:64-74. [PMID: 18400689 DOI: 10.1152/physiol.00040.2007] [Citation(s) in RCA: 200] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Accumulating data are documenting an inverse relationship between immune status, response to vaccination, health, and longevity, suggesting that the immune system becomes less effective with advancing age and that this is clinically relevant. The mechanisms and consequences of age-associated immune alterations, designated immunosenescence, are briefly reviewed here.
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Affiliation(s)
- Anis Larbi
- University of Tübingen, Center for Medical Research,Tübingen, Germany.
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23
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Fülöp T, Larbi A, Hirokawa K, Mocchegiani E, Lesourds B, Castle S, Wikby A, Franceschi C, Pawelec G. Immunosupportive therapies in aging. Clin Interv Aging 2008; 2:33-54. [PMID: 18044074 PMCID: PMC2684090 DOI: 10.2147/ciia.2007.2.1.33] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The primary role of the immune system is to protect the organism against pathogens, but age-associated alterations to immunity increase the susceptibility of the elderly to infectious disease. The exact nature of these changes is still controversial, but the use of screening procedures, such as the SENIEUR protocol to exclude underlying illness, helped to better characterize the changes actually related to physiological aging rather than pathology. It is generally agreed that the most marked changes occur in the cellular immune response reflecting profound alterations in T cells. Much of this is due to thymic involution as well as changes in the proportions of T cell subpopulations resulting from antigen exposure, and altered T cell activation pathways. However, a body of data indicates that innate immune responses, including the critical bridge between innate and adaptive immunity, and antigen presenting capacity are not completely resistant to senescence processes. The consequences of all these alterations are an increased incidence of infections, as well as possibly cancers, autoimmune disorders, and chronic inflammatory diseases. The leading question is what, if anything, can we do to prevent these deleterious changes without dangerously dysregulating the precarious balance of productive immunity versus immunopathology? There are many potential new therapeutic means now available to modulate immunosenescence and many others are expected to be available shortly. One main problem in applying these experimental therapies is ethical: there is a common feeling that as ageing is not a disease; the elderly are not sick and therefore do not require adventurous therapies with unpredictable side-effects in mostly frail individuals. Animal models are not helpful in this context. In this chapter we will first briefly review what we think we know about human immunosenescence and its consequences for the health status of elderly individuals. We will then discuss possible interventions that might one day become applicable in an appropriate ethical environment.
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Affiliation(s)
- Tamas Fülöp
- Research Center on Aging, Immunology Program, Geriatric Division, Faculty of Medicine, University of Sherbrooke, Sherbrooke, Quebec, Canada.
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24
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Duffield A, Caplan MJ, Muth TR. Chapter 4 Protein Trafficking in Polarized Cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 270:145-79. [DOI: 10.1016/s1937-6448(08)01404-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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25
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Owen DM, Neil MAA, French PMW, Magee AI. Optical techniques for imaging membrane lipid microdomains in living cells. Semin Cell Dev Biol 2007; 18:591-8. [PMID: 17728161 DOI: 10.1016/j.semcdb.2007.07.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Accepted: 07/20/2007] [Indexed: 10/23/2022]
Abstract
Lateral organisation of cellular membranes, particularly the plasma membrane, is of benefit to the cell as it allows complicated cellular processes to be regulated and efficient. For example, trafficking and secretion of molecules can be targeted and directed, cells polarised and signalling events modulated and propagated. The fluid mosaic model allows for significant heterogeneity on the part of the lipids themselves and of membrane associated proteins. By exploiting the tendency of complex lipid bilayers to undergo spontaneous or induced phase-separation into non-miscible domains, the cell could achieve this desired spatial organisation. While phase-separation is readily observed in simple, artificial bilayers, its occurrence in physiological membranes remains controversial. This stems mainly from our inability to image lipid microdomains directly - possibly due to their small size, short lifespan and/or morphological similarity to the bulk membrane. In this review, we seek to examine the techniques used to try to image membrane lipid microdomains, concentrating mainly on optical microscopy techniques that are applicable to live cells. We also look at novel emerging instruments and methods that promise to overcome our current technological limitations and shed new light on these important structures.
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Affiliation(s)
- Dylan M Owen
- Chemical Biology Centre, Imperial College London, London, UK.
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26
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Nejsum LN, Nelson WJ. A molecular mechanism directly linking E-cadherin adhesion to initiation of epithelial cell surface polarity. ACTA ACUST UNITED AC 2007; 178:323-35. [PMID: 17635938 PMCID: PMC2064450 DOI: 10.1083/jcb.200705094] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mechanisms involved in maintaining plasma membrane domains in fully polarized epithelial cells are known, but when and how directed protein sorting and trafficking occur to initiate cell surface polarity are not. We tested whether establishment of the basolateral membrane domain and E-cadherin–mediated epithelial cell–cell adhesion are mechanistically linked. We show that the basolateral membrane aquaporin (AQP)-3, but not the equivalent apical membrane AQP5, is delivered in post-Golgi structures directly to forming cell–cell contacts where it co-accumulates precisely with E-cadherin. Functional disruption of individual components of a putative lateral targeting patch (e.g., microtubules, the exocyst, and soluble N-ethylmaleimide–sensitive factor attachment protein receptors) did not inhibit cell–cell adhesion or colocalization of the other components with E-cadherin, but each blocked AQP3 delivery to forming cell–cell contacts. Thus, components of the lateral targeting patch localize independently of each other to cell–cell contacts but collectively function as a holocomplex to specify basolateral vesicle delivery to nascent cell–cell contacts and immediately initiate cell surface polarity.
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Affiliation(s)
- Lene N Nejsum
- Department of Biological Sciences and Department of Molecular and Cellular Physiology, The James H Clark Center, Bio-X Program, Stanford University, Stanford, CA 94305, USA
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27
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Williams GS, Collinson LM, Brzostek J, Eissmann P, Almeida CR, McCann FE, Burshtyn D, Davis DM. Membranous structures transfer cell surface proteins across NK cell immune synapses. Traffic 2007; 8:1190-204. [PMID: 17605758 DOI: 10.1111/j.1600-0854.2007.00603.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Intercellular transfer of cell surface proteins is widespread and facilitates several recently discovered means for immune cell communication. Here, we examined the molecular mechanism for intercellular exchange of the natural killer (NK) cell receptor KIR2DL1 and HLA-C, prototypical proteins that swap between NK cells and target cells. Transfer was contact dependent and enhanced for cells expressing cognate receptor/ligand pairs but did not depend on KIR2DL1 signaling. To a lesser extent, proteins transferred independent from specific recognition. Intracellular domains of transferred proteins were not exposed to the extracellular environment and transferred proteins were removed by brief exposure to low pH. By fluorescence microscopy, transferred proteins localized to discrete regions on the recipient cell surface. Higher resolution scanning electron micrographs revealed that transferred proteins were located within specific membranous structures. Transmission electron microscopy of the immune synapse revealed that membrane protrusions from one cell interacted with the apposing cell surface within the synaptic cleft. These data, coupled with previous observations, lead us to propose that intercellular protein transfer is mediated by membrane protrusions within and surrounding the immunological synapse.
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MESH Headings
- Acids/pharmacology
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/pharmacology
- Cell Communication/immunology
- Cell Line
- Cell Line, Tumor
- Cell Membrane/metabolism
- Cell Membrane/ultrastructure
- Cell Surface Extensions/metabolism
- Cell Surface Extensions/ultrastructure
- Coated Pits, Cell-Membrane/metabolism
- Coated Pits, Cell-Membrane/ultrastructure
- HLA-C Antigens/genetics
- HLA-C Antigens/metabolism
- Humans
- Intercellular Junctions/metabolism
- Intercellular Junctions/ultrastructure
- Killer Cells, Natural/cytology
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Membrane Proteins/metabolism
- Microscopy, Electron
- Organic Chemicals/metabolism
- Protein Binding
- Protein Transport/drug effects
- Pyrimidines/pharmacology
- Receptors, KIR2DL1/genetics
- Receptors, KIR2DL1/immunology
- Receptors, KIR2DL1/metabolism
- Transfection
- src-Family Kinases/antagonists & inhibitors
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Affiliation(s)
- Geoffrey S Williams
- Division of Cell and Molecular Biology, Sir Alexander Fleming Building, Imperial College London SW7 2AZ, UK
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28
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García-García E, Brown EJ, Rosales C. Transmembrane Mutations to FcγRIIA Alter Its Association with Lipid Rafts: Implications for Receptor Signaling. THE JOURNAL OF IMMUNOLOGY 2007; 178:3048-58. [PMID: 17312151 DOI: 10.4049/jimmunol.178.5.3048] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Many immunoreceptors have been reported to associate with lipid rafts upon ligand binding. The way in which this association is regulated is still obscure. We investigated the roles for various domains of the human immunoreceptor FcgammaRIIA in regulating its association with lipid rafts by determining the resistance of unligated, or ligated and cross-linked, receptors to solubilization by the nonionic detergent Triton X-100, when expressed in RBL-2H3 cells. Deletion of the cytoplasmic domain, or destruction of the cytoplasmic palmitoylation site, had no effect on the association of the receptor with lipid rafts. A transmembrane mutant, A224S, lost the ability to associate with lipid rafts upon receptor cross-linking, whereas transmembrane mutants VA231-2MM and VVAL234-7GISF showed constitutive lipid raft association. Wild-type (WT) FcgammaRIIA and all transmembrane mutants activated Syk, regardless of their association with lipid rafts. WT FcgammaRIIA and mutants that associated with lipid rafts efficiently activated NF-kappaB, in an ERK-dependent manner. In contrast, WT FcgammaRIIA and the A224S mutant both presented efficient phagocytosis, while VA231-2MM and VVAL234-7GISF mutants presented lower phagocytosis, suggesting that phagocytosis may proceed independently of lipid raft association. These data identify the transmembrane domain of FcgammaRIIA as responsible for regulating its inducible association with lipid rafts and suggest that FcgammaRIIA-mediated responses, like NF-kappaB activation or phagocytosis, can be modulated by lipid raft association of the ligated receptor.
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Affiliation(s)
- Erick García-García
- Immunology Department, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City D.F.-04510, Mexico
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29
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Subczynski WK, Wisniewska A, Hyde JS, Kusumi A. Three-dimensional dynamic structure of the liquid-ordered domain in lipid membranes as examined by pulse-EPR oxygen probing. Biophys J 2006; 92:1573-84. [PMID: 17142270 PMCID: PMC1796815 DOI: 10.1529/biophysj.106.097568] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Membranes made of dimyristoylphosphatidylcholine and cholesterol, one of the simplest paradigms for the study of liquid ordered-disordered phase separation, were investigated using a pulse-EPR spin-labeling method in which bimolecular collision of molecular oxygen with the nitroxide spin label is measured. This method allowed discrimination of liquid-ordered, liquid-disordered, and solid-ordered domains because the collision rates (OTP) differ in these domains. Furthermore, the oxygen transport parameter (OTP) profile across the bilayer provides unique information about the three-dimensional dynamic organization of the membrane domains. First, the OTP in the bilayer center in the liquid-ordered domain was comparable to that in the liquid-disordered domain without cholesterol, but the OTP near the membrane surface (up to carbon 9) was substantially smaller in the ordered domain, i.e., the cholesterol-based liquid-ordered domain is ordered only near the membrane surface, still retaining high levels of disorder in the bilayer center. This property may facilitate lateral mobility in ordered domains. Second, in the liquid-disordered domain, the domains with approximately 5 mol % cholesterol exhibited higher OTP than those without cholesterol, everywhere across the membrane. Third, the transmembrane OTP profile in the liquid-ordered domain that contained 50 mol % cholesterol dramatically differed from that which contained 27 mol % cholesterol.
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Affiliation(s)
- Witold K Subczynski
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
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Eisenberg S, Shvartsman DE, Ehrlich M, Henis YI. Clustering of raft-associated proteins in the external membrane leaflet modulates internal leaflet H-ras diffusion and signaling. Mol Cell Biol 2006; 26:7190-200. [PMID: 16980621 PMCID: PMC1592891 DOI: 10.1128/mcb.01059-06] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
One of the least-explored aspects of cholesterol-enriched domains (rafts) in cells is the coupling between such domains in the external and internal monolayers and its potential to modulate transbilayer signal transduction. Here, we employed fluorescence recovery after photobleaching to study the effects of antibody-mediated patching of influenza hemagglutinin (HA) proteins [raft-resident wild-type HA and glycosylphosphatidylinositol-anchored HA, or the nonraft mutant HA(2A520)] on the lateral diffusion of internal-leaflet raft and nonraft Ras isoforms (H-Ras and K-Ras, respectively). Our studies demonstrate that the clustering of outer-leaflet or transmembrane raft-associated HA proteins (but not their nonraft mutants) retards the lateral diffusion of H-Ras (but not K-Ras), suggesting stabilized interactions of H-Ras with the clusters of raft-associated HA proteins. These modulations were paralleled by specific effects on the activity of H-Ras but not of the nonraft K-Ras. Thus, clustering raft-associated HA proteins facilitated the early step whereby H-Ras is converted to an activated, GTP-loaded state but inhibited the ensuing step of downstream signaling via the Mek/Erk pathway. We propose a model for the modulation of transbilayer signaling by clustering of raft proteins, where external clustering (antibody or ligand mediated) enhances the association of internal-leaflet proteins with the stabilized clusters, promoting either enhancement or inhibition of signaling.
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Affiliation(s)
- Sharon Eisenberg
- Department of Neurobiochemistry, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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Shvartsman DE, Gutman O, Tietz A, Henis YI. Cyclodextrins but not compactin inhibit the lateral diffusion of membrane proteins independent of cholesterol. Traffic 2006; 7:917-26. [PMID: 16787400 DOI: 10.1111/j.1600-0854.2006.00437.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cholesterol and glycosphingolipid-enriched membrane domains, termed lipid rafts, were proposed to play important roles in trafficking and signaling events. These functions are inhibited following putative disruption of rafts by cholesterol depletion, commonly induced by treatment with methyl-beta-cyclodextrin (MbetaCD). However, several studies showed that the lateral diffusion of membrane proteins is inhibited by MbetaCD, suggesting that it may have additional effects on membrane organization unrelated to cholesterol removal. Here, we investigated this possibility by comparison of the effects of cholesterol depletion by MbetaCD and by metabolic inhibition (compactin), and of treatment with alpha-CD, which does not bind cholesterol. The studies employed two series of proteins (Ras and influenza hemagglutinin), each containing as internal controls related mutants that differ in raft association. Mild MbetaCD treatment retarded the lateral diffusion of both raft and non-raft mutants, whereas similar cholesterol reduction (30-33%) by metabolic inhibition enhanced selectively the diffusion of the raft-associated mutants. Moreover, alpha-CD also inhibited the diffusion of raft and non-raft mutants, despite its lack of effect on cholesterol content. These findings suggest that the widely used treatment with CD to reduce cholesterol has additional, cholesterol-independent effects on membrane protein mobility, which do not necessarily distinguish between raft and non-raft proteins.
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Affiliation(s)
- Dmitry E Shvartsman
- Department of Neurobiochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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Fulop T, Larbi A, Wikby A, Mocchegiani E, Hirokawa K, Pawelec G. Dysregulation of T-cell function in the elderly : scientific basis and clinical implications. Drugs Aging 2006; 22:589-603. [PMID: 16038574 DOI: 10.2165/00002512-200522070-00005] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The function of the immune system is to maintain body integrity by defending against infections, cancers, autoimmune diseases and inflammation-related chronic diseases. The immune response is known to become defective with aging, leading to decreased longevity and appearance of age-related disease. The most important changes occur in T-cell immunity, and are manifested particularly as altered clonal expansion of cells of limited antigen specificity. The causes of these alterations are multifactorial, and include thymic involution, T-cell subset changes and signal transduction alterations. The clinical consequences of these changes are not well defined, except for their extremely important negative impact on defence against infections, especially by new pathogens, and decreased responses to vaccination. Considering the public health consequences of decreased immune competence in old age, strategies for immune response modulation are desirable to decrease the health burden for the elderly and improve their quality of life.
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Affiliation(s)
- Tamas Fulop
- Immunology Program, Geriatric Division, Research Center on Aging, Faculty of Medicine, University of Sherbrooke, Sherbrooke, Quebec, Canada.
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Roda-Navarro P, Vales-Gomez M, Chisholm SE, Reyburn HT. Transfer of NKG2D and MICB at the cytotoxic NK cell immune synapse correlates with a reduction in NK cell cytotoxic function. Proc Natl Acad Sci U S A 2006; 103:11258-63. [PMID: 16849432 PMCID: PMC1544075 DOI: 10.1073/pnas.0600721103] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Indexed: 12/30/2022] Open
Abstract
Although transfer of membrane proteins has been shown to occur during immune cell interactions, the functional significance of this process is not well understood. Here we describe the intercellular transfer of NKG2D and MHC class I chain-related molecule (MIC) B proteins at the cytotoxic natural killer cell immune synapse (cNK-IS). MICB expressed on the 721.221 cell line induced clustering of NKG2D at the central supramolecular activation cluster, surrounded by a peripheral supramolecular activation cluster containing F-actin. Moreover, natural killer (NK) cell membrane-connective structures formed during cytotoxic interactions contained F-actin, perforin, and NKG2D. NKG2D transfer depended on binding to MICB and was specific because transfer of other molecules not involved in NK-IS formation was not observed. Transfer of MICB to NK cells also was noted, suggesting a bidirectional exchange of receptor/ligand pairs at cNK-IS. Experiments designed to test the functional significance of these observations revealed that brief interactions between NK cells and MICB expressing target cells led to a reduction in NKG2D-dependent NK cytotoxicity. These data demonstrate interchange of an activating receptor and its ligand at the cNK-IS and document a correlation between synapse organization, intercellular protein transfer, and compromised NK cell function after interaction with a susceptible target cell.
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Affiliation(s)
- Pedro Roda-Navarro
- Division of Immunology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
| | - Mar Vales-Gomez
- Division of Immunology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
| | - Susan E. Chisholm
- Division of Immunology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
| | - Hugh T. Reyburn
- Division of Immunology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
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Abstract
Within the paradigm of the two-signal model of lymphocyte activation, the interest in costimulation has witnessed a remarkable emergence in the past few years with the discovery of a large array of molecules that can serve this role, including some with an inhibitory function. Interest has been further enhanced by the realization of these molecules' potential as targets to modulate clinical immune responses. Although the therapeutic translation of mechanistic knowledge in costimulatory molecules has been relatively straightforward, the capacity to target their inhibitory counterparts has remained limited. This limited capacity is particularly apparent in the case of the cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), a major negative regulator of T cell responses. Because there have been several previous comprehensive reviews on the function of this molecule, we focus here on the physiological implications of its structural features. Such an exercise may ultimately help us to design immunotherapeutic agents that target CTLA-4.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigens, CD
- Antigens, Differentiation/chemistry
- Antigens, Differentiation/genetics
- Antigens, Differentiation/metabolism
- Biological Transport, Active
- CTLA-4 Antigen
- Dimerization
- Evolution, Molecular
- Humans
- Ligands
- Lymphocyte Activation
- Models, Immunological
- Molecular Biology
- Molecular Sequence Data
- Polymorphism, Genetic
- Protein Structure, Quaternary
- Sequence Homology, Amino Acid
- Signal Transduction
- T-Lymphocytes/immunology
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Affiliation(s)
- Wendy A Teft
- The FOCIS Center for Clinical Immunology and Immunotherapeutics, Robarts Research Institute, and Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada, N6A 5K8
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Abstract
Cell-to-cell spread of retroviruses via virological synapse (VS) contributes to overall progression of disease. VS are specialized pathogen-induced cellular structures that facilitate cell-to-cell transfer of HIV-1 and HTLV-1. VS provide a mechanistic explanation for cell-associated retroviral replication. While VS share some common features with neurological or immunological synapses, they also exhibit important differences. The role of VS might not be limited to human retroviruses and the emerging role of a plant synapse suggests that VS might well be conserved structures for cell-cell spreading of both animal and plant viruses. Dissection of the VS is just at its beginning, but already offers ample information and fascinating insights into mechanisms of viral replication and cell-to-cell communication.
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Affiliation(s)
- Eduardo Garcia
- Department of Dermatology and Venereology, University Hospital of Geneva, 4-747, 24 Rue Micheli-du-Crest, 1211 Geneva, Switzerland
| | - Vincent Piguet
- Department of Dermatology and Venereology, University Hospital of Geneva, 4-747, 24 Rue Micheli-du-Crest, 1211 Geneva, Switzerland
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Abstract
Cells of the immune system communicate via the formation of receptor-containing adhesive junctions termed immunological synapses. Recently, retroviruses have been shown to subvert this process in order to pass directly from infected to uninfected immune cells. Such cell-cell viral dissemination appears to function by triggering existing cellular pathways involved in antigen presentation and T-cell communication. This mode of viral spread has important consequences for both the virus and the host cells in terms of viral pathogenesis and viral resistance to immune and therapeutic intervention. This review summarises the current knowledge concerning virological synapses induced by retroviruses.
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Affiliation(s)
- Clare Jolly
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE.
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