1
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Schmidt EN, Guo XY, Bui DT, Jung J, Klassen JS, Macauley MS. Dissecting the abilities of murine Siglecs to interact with gangliosides. J Biol Chem 2024; 300:107482. [PMID: 38897567 PMCID: PMC11294694 DOI: 10.1016/j.jbc.2024.107482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 05/21/2024] [Accepted: 06/10/2024] [Indexed: 06/21/2024] Open
Abstract
Siglecs are cell surface receptors whose functions are tied to the binding of their sialoglycan ligands. Recently, we developed an optimized liposome formulation and used it to investigate the binding of human Siglecs (hSiglec) against a panel of gangliosides. Animal models, more specifically murine models, are used to understand human biology; however, species-specific differences can complicate the interpretation of the results. Herein, we used our optimized liposome formulation to dissect the interactions between murine Siglecs (mSiglecs) and gangliosides to assess the appropriateness of mSiglecs as a proxy to better understand the biological roles of hSiglec-ganglioside interactions. Using our optimized liposome formulation, we found that ganglioside binding is generally conserved between mice and humans with mSiglec-1, -E, -F, and -15 binding multiple gangliosides like their human counterparts. However, in contrast to the hSiglecs, we observed little to no binding between the mSiglecs and ganglioside GM1a. Detailed analysis of mSiglec-1 interacting with GM1a and its structural isomer, GM1b, suggests that mSiglec-1 preferentially binds α2-3-linked sialic acids presented from the terminal galactose residue. The ability of mSiglecs to interact or not interact with gangliosides, particularly GM1a, has implications for using mice to study neurodegenerative diseases, infections, and cancer, where interactions between Siglecs and glycolipids have been proposed to modulate these human diseases.
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Affiliation(s)
- Edward N Schmidt
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Xue Yan Guo
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Duong T Bui
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Jaesoo Jung
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - John S Klassen
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Matthew S Macauley
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada; Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada.
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2
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Xu Z, Liu Y, Liu J, Ma W, Zhang Z, Chapla DG, Wen L, Moremen KW, Yi W, Li T. Integrated chemoenzymatic synthesis of a comprehensive sulfated ganglioside glycan library to decipher functional sulfoglycomics and sialoglycomics. Nat Chem 2024; 16:881-892. [PMID: 38844638 DOI: 10.1038/s41557-024-01540-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 04/19/2024] [Indexed: 06/12/2024]
Abstract
Ganglioside glycans are ubiquitous and complex biomolecules that are involved in a wide range of biological functions and disease processes. Variations in sialylation and sulfation render the structural complexity and diversity of ganglioside glycans, and influence protein-carbohydrate interactions. Structural and functional insights into the biological roles of these glycans are impeded due to the limited accessibility of well-defined structures. Here we report an integrated chemoenzymatic strategy for expeditious and systematic synthesis of a comprehensive 65-membered ganglioside glycan library covering all possible patterns of sulfation and sialylation. This strategy relies on the streamlined modular assembly of three common sialylated precursors by highly stereoselective iterative sialylation, modular site-specific sulfation through flexible orthogonal protecting-group manipulations and enzymatic-catalysed diversification using three sialyltransferase modules and a galactosidase module. These diverse ganglioside glycans enable exploration into their structure-function relationships using high-throughput glycan microarray technology, which reveals that different patterns of sulfation and sialylation on these glycans mediate their unique binding specificities.
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Affiliation(s)
- Zhuojia Xu
- State Key Laboratory of Chemical Biology, Carbohydrate-Based Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yating Liu
- State Key Laboratory of Chemical Biology, Carbohydrate-Based Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Jialin Liu
- State Key Laboratory of Chemical Biology, Carbohydrate-Based Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Wenjing Ma
- State Key Laboratory of Chemical Biology, Carbohydrate-Based Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhumin Zhang
- State Key Laboratory of Chemical Biology, Carbohydrate-Based Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | | | - Liuqing Wen
- State Key Laboratory of Chemical Biology, Carbohydrate-Based Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Kelley W Moremen
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Wen Yi
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Tiehai Li
- State Key Laboratory of Chemical Biology, Carbohydrate-Based Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
- University of Chinese Academy of Sciences, Beijing, China.
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3
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Coccimiglio M, Chiodo F, van Kooyk Y. The sialic acid-Siglec immune checkpoint: an opportunity to enhance immune responses and therapy effectiveness in melanoma. Br J Dermatol 2024; 190:627-635. [PMID: 38197441 DOI: 10.1093/bjd/ljad517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 12/13/2023] [Accepted: 12/17/2023] [Indexed: 01/11/2024]
Abstract
Modulation of immune responses through immune checkpoint blockade has revolutionized cutaneous melanoma treatment. However, it is still the case that not all patients respond successfully to these therapies, indicating the presence of as yet unknown resistance mechanisms. Hence, it is crucial to find novel targets to improve therapy efficacy. One of the described resistance mechanisms is regulated by immune inhibitory Siglec receptors, which are engaged by the carbohydrates sialic acids expressed on tumour cells, contributing to programmed cell death protein-1 (PD1)-like immune suppression mechanisms. In this review, we provide an overview on the regulation of sialic acid synthesis, its expression in melanoma, and the contribution of the sialic acid-Siglec axis to tumour development and immune suppressive mechanisms in the tumour microenvironment. Finally, we highlight potential sialic acid-Siglec axis-related therapeutics to improve the treatment of melanoma.
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Affiliation(s)
- Magali Coccimiglio
- Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Department of Molecular Cell Biology and Immunology, Amsterdam, the Netherlands
- Cancer Center Amsterdam, Amsterdam, the Netherlands
- Amsterdam Institute for Infection and Immunity, Amsterdam, the Netherlands
| | - Fabrizio Chiodo
- Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Department of Molecular Cell Biology and Immunology, Amsterdam, the Netherlands
- Cancer Center Amsterdam, Amsterdam, the Netherlands
- Amsterdam Institute for Infection and Immunity, Amsterdam, the Netherlands
- Italian National Research Council, Institute of Biomolecular Chemistry, Pozzuoli, Naples, Italy
| | - Yvette van Kooyk
- Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Department of Molecular Cell Biology and Immunology, Amsterdam, the Netherlands
- Cancer Center Amsterdam, Amsterdam, the Netherlands
- Amsterdam Institute for Infection and Immunity, Amsterdam, the Netherlands
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4
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Boelaars K, van Kooyk Y. Targeting myeloid cells for cancer immunotherapy: Siglec-7/9/10/15 and their ligands. Trends Cancer 2024; 10:230-241. [PMID: 38160071 DOI: 10.1016/j.trecan.2023.11.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/17/2023] [Accepted: 11/28/2023] [Indexed: 01/03/2024]
Abstract
Advances in immunotherapy have revolutionized cancer treatment, yet many patients do not show clinical responses. While most immunotherapies target T cells, myeloid cells are the most abundant cell type in solid tumors and are key orchestrators of the immunosuppressive tumor microenvironment (TME), hampering effective T cell responses. Therefore, unraveling the immune suppressive pathways within myeloid cells could unveil new avenues for cancer immunotherapy. Over the past decade, Siglec receptors and their ligand, sialic acids, have emerged as a novel immune checkpoint on myeloid cells. In this review, we highlight key findings on how sialic acids modify immunity in the TME through engagement of Siglec-7/9/10/15 expressed on myeloid cells, and how the sialic acid-Siglec axis can be targeted for future cancer immunotherapies.
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Affiliation(s)
- Kelly Boelaars
- Amsterdam UMC location Vrije Universiteit Amsterdam, Molecular Cell Biology and Immunology, Cancer Center Amsterdam, Amsterdam Institute for Infection and Immunity, De Boelelaan, 1117, Amsterdam, The Netherlands
| | - Yvette van Kooyk
- Amsterdam UMC location Vrije Universiteit Amsterdam, Molecular Cell Biology and Immunology, Cancer Center Amsterdam, Amsterdam Institute for Infection and Immunity, De Boelelaan, 1117, Amsterdam, The Netherlands.
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5
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Schnider B, M’Rad Y, el Ahmadie J, de Brevern AG, Imberty A, Lisacek F. HumanLectome, an update of UniLectin for the annotation and prediction of human lectins. Nucleic Acids Res 2024; 52:D1683-D1693. [PMID: 37889052 PMCID: PMC10767822 DOI: 10.1093/nar/gkad905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 10/03/2023] [Accepted: 10/06/2023] [Indexed: 10/28/2023] Open
Abstract
The UniLectin portal (https://unilectin.unige.ch/) was designed in 2019 with the goal of centralising curated and predicted data on carbohydrate-binding proteins known as lectins. UniLectin is also intended as a support for the study of lectomes (full lectin set) of organisms or tissues. The present update describes the inclusion of several new modules and details the latest (https://unilectin.unige.ch/humanLectome/), covering our knowledge of the human lectome and comprising 215 unevenly characterised lectins, particularly in terms of structural information. Each HumanLectome entry is protein-centric and compiles evidence of carbohydrate recognition domain(s), specificity, 3D-structure, tissue-based expression and related genomic data. Other recent improvements regarding interoperability and accessibility are outlined.
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Affiliation(s)
- Boris Schnider
- Proteome Informatics Group, SIB Swiss Institute of Bioinformatics, CH-1211 Geneva, Switzerland
- Computer Science Department, University of Geneva, CH-1227 Geneva, Switzerland
| | - Yacine M’Rad
- Proteome Informatics Group, SIB Swiss Institute of Bioinformatics, CH-1211 Geneva, Switzerland
- Computer Science Department, University of Geneva, CH-1227 Geneva, Switzerland
| | - Jalaa el Ahmadie
- Proteome Informatics Group, SIB Swiss Institute of Bioinformatics, CH-1211 Geneva, Switzerland
- Computer Science Department, University of Geneva, CH-1227 Geneva, Switzerland
- University Grenoble Alpes, CNRS, CERMAV, F-38000 Grenoble, France
| | - Alexandre G de Brevern
- Université Paris Cité and Université de la Réunion and Université des Antilles, INSERM, BIGR, DSIMB Bioinformatics Team, F-75014 Paris, France
| | - Anne Imberty
- University Grenoble Alpes, CNRS, CERMAV, F-38000 Grenoble, France
| | - Frederique Lisacek
- Proteome Informatics Group, SIB Swiss Institute of Bioinformatics, CH-1211 Geneva, Switzerland
- Computer Science Department, University of Geneva, CH-1227 Geneva, Switzerland
- Section of Biology, University of Geneva, CH-1205 Geneva, Switzerland
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6
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Schengrund CL. The Ying and Yang of Ganglioside Function in Cancer. Cancers (Basel) 2023; 15:5362. [PMID: 38001622 PMCID: PMC10670608 DOI: 10.3390/cancers15225362] [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: 09/29/2023] [Revised: 10/23/2023] [Accepted: 10/28/2023] [Indexed: 11/26/2023] Open
Abstract
The plethora of information about the expression of cancer cell-associated gangliosides, their role(s) in signal transduction, and their potential usefulness in the development of cancer treatments makes this an appropriate time to review these enigmatic glycosphingolipids. Evidence, reflecting the work of many, indicates that (1) expression of specific gangliosides, not generally found in high concentrations in most normal human cells, can be linked to certain types of cancer. (2) Gangliosides can affect the ability of cells to interact either directly or indirectly with growth factor receptors, thereby changing such things as a cell's mobility, rate of proliferation, and metastatic ability. (3) Anti-ganglioside antibodies have been tested, with some success, as potential treatments for certain cancers. (4) Cancer-associated gangliosides shed into the circulation can (a) affect immune cell responsiveness either positively or negatively, (b) be considered as diagnostic markers, and (c) be used to look for recurrence. (5) Cancer registries enable investigators to evaluate data from sufficient numbers of patients to obtain information about potential therapies. Despite advances that have been made, a discussion of possible approaches to identifying additional treatment strategies to inhibit metastasis, responsible for the majority of deaths of cancer patients, as well as for treating therapy-resistant tumors, is included.
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Affiliation(s)
- Cara-Lynne Schengrund
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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7
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Schmidt EN, Lamprinaki D, McCord KA, Joe M, Sojitra M, Waldow A, Nguyen J, Monyror J, Kitova EN, Mozaneh F, Guo XY, Jung J, Enterina JR, Daskhan GC, Han L, Krysler AR, Cromwell CR, Hubbard BP, West LJ, Kulka M, Sipione S, Klassen JS, Derda R, Lowary TL, Mahal LK, Riddell MR, Macauley MS. Siglec-6 mediates the uptake of extracellular vesicles through a noncanonical glycolipid binding pocket. Nat Commun 2023; 14:2327. [PMID: 37087495 PMCID: PMC10122656 DOI: 10.1038/s41467-023-38030-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 04/12/2023] [Indexed: 04/24/2023] Open
Abstract
Immunomodulatory Siglecs are controlled by their glycoprotein and glycolipid ligands. Siglec-glycolipid interactions are often studied outside the context of a lipid bilayer, missing the complex behaviors of glycolipids in a membrane. Through optimizing a liposomal formulation to dissect Siglec-glycolipid interactions, it is shown that Siglec-6 can recognize glycolipids independent of its canonical binding pocket, suggesting that Siglec-6 possesses a secondary binding pocket tailored for recognizing glycolipids in a bilayer. A panel of synthetic neoglycolipids is used to probe the specificity of this glycolipid binding pocket on Siglec-6, leading to the development of a neoglycolipid with higher avidity for Siglec-6 compared to natural glycolipids. This neoglycolipid facilitates the delivery of liposomes to Siglec-6 on human mast cells, memory B-cells and placental syncytiotrophoblasts. A physiological relevance for glycolipid recognition by Siglec-6 is revealed for the binding and internalization of extracellular vesicles. These results demonstrate a unique and physiologically relevant ability of Siglec-6 to recognize glycolipids in a membrane.
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Affiliation(s)
- Edward N Schmidt
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | | | - Kelli A McCord
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Maju Joe
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Mirat Sojitra
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Ayk Waldow
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Jasmine Nguyen
- Department of Obstetrics & Gynaecology and Physiology University of Alberta, Edmonton, AB, Canada
| | - John Monyror
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Elena N Kitova
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Fahima Mozaneh
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Xue Yan Guo
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Jaesoo Jung
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Jhon R Enterina
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada
| | - Gour C Daskhan
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Ling Han
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Amanda R Krysler
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | | | - Basil P Hubbard
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Lori J West
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
- Department of Surgery, University of Alberta, Edmonton, AB, Canada
| | - Marianne Kulka
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada
- National Research Council, Edmonton, AB, Canada
| | - Simonetta Sipione
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - John S Klassen
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Ratmir Derda
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Todd L Lowary
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
- Institute of Biological Chemistry, Academia Sinica, Nangang, Taipei, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Lara K Mahal
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Meghan R Riddell
- Department of Obstetrics & Gynaecology and Physiology University of Alberta, Edmonton, AB, Canada
| | - Matthew S Macauley
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada.
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada.
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8
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Schnaar RL. Gangliosides as Siglec ligands. Glycoconj J 2023; 40:159-167. [PMID: 36701102 PMCID: PMC11000168 DOI: 10.1007/s10719-023-10101-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/09/2023] [Accepted: 01/13/2023] [Indexed: 01/27/2023]
Abstract
The structure of a sialoglycan can be translated into to a biological response when it binds to a specific endogenous lectin. Among endogenous sialic acid-binding lectins in humans are those comprising the 15-member Siglec family, most of which are expressed on overlapping sets of immune cells. Endogenous Siglec ligands are sialoglycolipids (gangliosides) and/or sialoglycoproteins, on cell surfaces or in the extracellular milieu, that bind to and initiate signaling by cell surface Siglecs. In the nervous system, where gangliosides are the predominant sialoglycans, Siglec-4 (myelin-associated glycoprotein) on myelinating cells binds to gangliosides GD1a and GT1b on nerve cell axons to ensure stable and productive axon-myelin interactions. In the immune system, Siglec-7 on natural killer cells binds to gangliosides GD3 and GD2 to inhibit immune signaling. Expression of GD3 and GD2 on cancer cells can lead to tumor immune evasion. Siglec-1 (sialoadhesin, CD169) on macrophages binds to gangliosides on tumors and enveloped viruses. This may enhance antigen presentation in some cases, or increase viral distribution in others. Several other Siglecs bind to gangliosides in vitro, the biological significance of which has yet to be fully established. Gangliosides, which are found on all human cells and tissues in cell-specific distributions, are functional Siglec ligands with varied roles driving Siglec-mediated signaling.
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Affiliation(s)
- Ronald L Schnaar
- Department of Pharmacology and Molecular Sciences, Department of Neuroscience, Johns Hopkins University School of Medicine, 725 N Wolfe St, Baltimore, MD, 21205, USA.
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9
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Tsubata T. Role of inhibitory B cell co-receptors in B cell self-tolerance to non-protein antigens. Immunol Rev 2022; 307:53-65. [PMID: 34989000 DOI: 10.1111/imr.13059] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 12/14/2022]
Abstract
Antibodies to non-protein antigens such as nucleic acids, polysaccharides, and glycolipids play important roles in both host defense against microbes and development of autoimmune diseases. Although non-protein antigens are not recognized by T cells, antibody production to non-protein antigens involve T cell-independent mechanisms such as signaling through TLR7 and TLR9 in antibody production to nucleic acids. Although self-reactive B cells are tolerized by various mechanisms including deletion, anergy, and receptor editing, T cell tolerance is also crucial in self-tolerance of B cells to protein self-antigen because self-reactive T cells induce autoantibody production to these self-antigens. However, presence of T cell-independent mechanism suggests that T cell tolerance is not able to maintain B cell tolerance to non-protein self-antigens. Lines of evidence suggest that B cell response to non-protein self-antigens such as nucleic acids and gangliosides, sialic acid-containing glycolipids, are suppressed by inhibitory B cell co-receptors CD72 and Siglec-G, respectively. These inhibitory co-receptors recognize non-protein self-antigens and suppress BCR signaling induced by these antigens, thereby inhibiting B cell response to these self-antigens. Inhibitory B cell co-receptors appear to be involved in B cell self-tolerance to non-protein self-antigens that can activate B cells by T cell-independent mechanisms.
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Affiliation(s)
- Takeshi Tsubata
- Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
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10
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Hugonnet M, Singh P, Haas Q, von Gunten S. The Distinct Roles of Sialyltransferases in Cancer Biology and Onco-Immunology. Front Immunol 2021; 12:799861. [PMID: 34975914 PMCID: PMC8718907 DOI: 10.3389/fimmu.2021.799861] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 12/02/2021] [Indexed: 12/24/2022] Open
Abstract
Aberrant glycosylation is a key feature of malignant transformation. Hypersialylation, the enhanced expression of sialic acid-terminated glycoconjugates on the cell surface, has been linked to immune evasion and metastatic spread, eventually by interaction with sialoglycan-binding lectins, including Siglecs and selectins. The biosynthesis of tumor-associated sialoglycans involves sialyltransferases, which are differentially expressed in cancer cells. In this review article, we provide an overview of the twenty human sialyltransferases and their roles in cancer biology and immunity. A better understanding of the individual contribution of select sialyltransferases to the tumor sialome may lead to more personalized strategies for the treatment of cancer.
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Affiliation(s)
- Marjolaine Hugonnet
- Institute of Pharmacology, University of Bern, Bern, Switzerland
- Bern Center for Precision Medicine (BCPM), University of Bern, Bern, Switzerland
| | - Pushpita Singh
- Institute of Pharmacology, University of Bern, Bern, Switzerland
| | - Quentin Haas
- Institute of Pharmacology, University of Bern, Bern, Switzerland
| | - Stephan von Gunten
- Institute of Pharmacology, University of Bern, Bern, Switzerland
- Bern Center for Precision Medicine (BCPM), University of Bern, Bern, Switzerland
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11
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Salminen A, Kaarniranta K, Kauppinen A. Hypoxia/ischemia impairs CD33 (Siglec-3)/TREM2 signaling: Potential role in Alzheimer's pathogenesis. Neurochem Int 2021; 150:105186. [PMID: 34530055 DOI: 10.1016/j.neuint.2021.105186] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/10/2021] [Accepted: 09/12/2021] [Indexed: 12/22/2022]
Abstract
Recent genetic and molecular studies have indicated that the innate immune system, especially microglia, have a crucial role in the accumulation of β-amyloid plaques in Alzheimer's disease (AD). In particular, the CD33 receptor, also called Siglec-3, inhibits the TREM2 receptor-induced phagocytic activity of microglia. CD33 receptors recognize the α2,3 and α2,6-linked sialic groups in tissue glycocalyx, especially sialylated gangliosides in human brain. The CD33 receptor triggers cell-type specific responses, e.g., in microglia, CD33 inhibits phagocytosis, whereas in natural killer cells, it inhibits the cytotoxic activity of the NKG2D receptor. Nonetheless, the regulation of the activity of CD33 receptor needs to be clarified. For example, it seems that hypoxia/ischemia, a potential cause of AD pathology, increases the expression of CD33 and its downstream target SHP-1, a tyrosine phosphatase which suppresses the phagocytosis driven by TREM2. Moreover, hypoxia/ischemia increases the deposition of sialylated gangliosides, e.g., GM1, GM2, GM3, and GD1, which are ligands for inhibitory CD33/Siglec-3 receptors. In addition, β-amyloid peptides bind to the sialylated gangliosides in raft-like clusters and subsequently these gangliosides act as seeds for the formation of β-amyloid plaques in AD pathology. It is known that senile plaques contain sialylated GM1, GM2, and GM3 gangliosides, i.e., the same species induced by hypoxia/ischemia treatment. Sialylated gangliosides in plaques might stimulate the CD33/Siglec-3 receptors of microglia and thus impede TREM2-driven phagocytosis. We propose that hypoxia/ischemia, e.g., via the accumulation of sialylated gangliosides, prevents the phagocytosis of β-amyloid deposits by inhibiting CD33/TREM2 signaling.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland.
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 100, FI-70029, KYS, Finland
| | - Anu Kauppinen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland
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12
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First Evidence for a Role of Siglec-8 in Breast Cancer. Int J Mol Sci 2021; 22:ijms22042000. [PMID: 33670444 PMCID: PMC7922794 DOI: 10.3390/ijms22042000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/10/2021] [Accepted: 02/12/2021] [Indexed: 12/20/2022] Open
Abstract
Sialic acid-binding immunoglobulin-like lectins (Siglecs) are involved in various immune cell-mediated diseases. Their role in cancer is poorly investigated, and research focusses on Siglec-expression on immune cells interacting with tumor cells. This study evaluates the role of Siglec-8 in breast cancer (BC). Siglec-8 expression was analyzed immunohistochemically on 235 primary BC cases and was correlated with clinical and pathological parameters and outcome. Cell culture experiments were performed with various BC cell lines. Siglec-8 was expressed in 215 BC cases and expression was lowest in triple-negative BC. It correlated with estrogen receptor-status, grading and the prognostic factors galectin (Gal)-7 and tumor-associated mucin-1 (TA-MUC1). However, Gal-7 and TA-MUC1 were only prognosticators for clinical outcome in the cohort expressing high (Immunoreactivity score IRS > 3) Siglec-8 levels but not in the low-expressing cohort. Siglec-8 knockdown led to a significantly reduced Gal-7 expression in MCF7 cells. All BC cell lines expressed low Siglec-8-levels, that could be elevated in MCF7 by Peroxisome proliferator-activated receptor (PPARγ)-stimulation. This study demonstrates that Siglec-8 is expressed in BC cells and correlates with known clinical and prognostic parameters. It is probably associated with Gal-7 and TA-MUC1 and might be regulated via PPARγ. Further analyses focusing on functional associations will clarify Siglec-8’s eligibility as a possible therapeutic target.
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Rosenstock P, Kaufmann T. Sialic Acids and Their Influence on Human NK Cell Function. Cells 2021; 10:263. [PMID: 33572710 PMCID: PMC7911748 DOI: 10.3390/cells10020263] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/26/2021] [Accepted: 01/26/2021] [Indexed: 12/14/2022] Open
Abstract
Sialic acids are sugars with a nine-carbon backbone, present on the surface of all cells in humans, including immune cells and their target cells, with various functions. Natural Killer (NK) cells are cells of the innate immune system, capable of killing virus-infected and tumor cells. Sialic acids can influence the interaction of NK cells with potential targets in several ways. Different NK cell receptors can bind sialic acids, leading to NK cell inhibition or activation. Moreover, NK cells have sialic acids on their surface, which can regulate receptor abundance and activity. This review is focused on how sialic acids on NK cells and their target cells are involved in NK cell function.
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Affiliation(s)
- Philip Rosenstock
- Institute for Physiological Chemistry, Martin-Luther-University Halle-Wittenberg, Hollystr. 1, D-06114 Halle/Saale, Germany;
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14
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Alborzian Deh Sheikh A, Gomaa S, Li X, Routledge M, Saigoh K, Numoto N, Angata T, Hitomi Y, Takematsu H, Tsuiji M, Ito N, Kusunoki S, Tsubata T. A Guillain-Barré syndrome-associated SIGLEC10 rare variant impairs its recognition of gangliosides. J Autoimmun 2020; 116:102571. [PMID: 33223341 DOI: 10.1016/j.jaut.2020.102571] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/31/2020] [Accepted: 11/05/2020] [Indexed: 01/05/2023]
Abstract
Guillain-Barré syndrome (GBS), including its variant Miller Fisher syndrome (MFS), is an acute peripheral neuropathy that involves autoimmune mechanisms leading to the production of autoantibodies to gangliosides; sialic acid-containing glycosphingolipids. Although association with various genetic polymorphisms in the major histocompatibility complex (MHC) is shown in other autoimmune diseases, GBS is an exception, showing no such link. No significant association was found by genome wide association studies, suggesting that GBS is not associated with common variants. To address the involvement of rare variants in GBS, we analyzed Siglec-10, a sialic acid-recognizing inhibitory receptor expressed on B cells. Here we demonstrate that two rare variants encoding R47Q and A108V substitutions in the ligand-binding domain are significantly accumulated in patients with GBS. Because of strong linkage disequilibrium, there was no patient carrying only one of them. Recombinant Siglec-10 protein containing R47Q but not A108V shows impaired binding to gangliosides. Homology modeling revealed that the R47Q substitution causes marked alteration in the ligand-binding site. Thus, GBS is associated with a rare variant of the SIGLEC10 gene that impairs ligand binding of Siglec-10. Because Siglec-10 regulates antibody production to sialylated antigens, our finding suggests that Siglec-10 regulates development of GBS by suppressing antibody production to gangliosides, with defects in its function predisposing to disease.
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Affiliation(s)
- Amin Alborzian Deh Sheikh
- Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Soha Gomaa
- Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan; Division of Immunology and Biotechnology, Faculty of Science, Tanta University, Tanta, Egypt
| | - Xuexin Li
- Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Matthew Routledge
- Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kazumasa Saigoh
- Department of Neurology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Nobutaka Numoto
- Department of Structural Biology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takashi Angata
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Yuki Hitomi
- Department of Microbiology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan
| | - Hiromu Takematsu
- Faculty of Medical Technology, Fujita Health University, Toyoake, Aichi, Japan
| | - Makoto Tsuiji
- Department of Microbiology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan
| | - Nobutoshi Ito
- Department of Structural Biology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Susumu Kusunoki
- Department of Neurology, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Takeshi Tsubata
- Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan.
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15
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Bartish M, Del Rincón SV, Rudd CE, Saragovi HU. Aiming for the Sweet Spot: Glyco-Immune Checkpoints and γδ T Cells in Targeted Immunotherapy. Front Immunol 2020; 11:564499. [PMID: 33133075 PMCID: PMC7550643 DOI: 10.3389/fimmu.2020.564499] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 08/31/2020] [Indexed: 11/23/2022] Open
Abstract
Though a healthy immune system is capable of recognizing and eliminating emergent cancerous cells, an established tumor is adept at escaping immune surveillance. Altered and tumor-specific expression of immunosuppressive cell surface carbohydrates, also termed the “tumor glycocode,” is a prominent mechanism by which tumors can escape anti-tumor immunity. Given their persistent and homogeneous expression, tumor-associated glycans are promising targets to be exploited as biomarkers and therapeutic targets. However, the exploitation of these glycans has been a challenge due to their low immunogenicity, immunosuppressive properties, and the inefficient presentation of glycolipids in a conventional major histocompatibility complex (MHC)-restricted manner. Despite this, a subset of T-cells expressing the gamma and delta chains of the T-cell receptor (γδ T cells) exist with a capacity for MHC-unrestricted antigen recognition and potent inherent anti-tumor properties. In this review, we discuss the role of tumor-associated glycans in anti-tumor immunity, with an emphasis on the potential of γδ T cells to target the tumor glycocode. Understanding the many facets of this interaction holds the potential to unlock new ways to use both tumor-associated glycans and γδ T cells in novel therapeutic interventions.
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Affiliation(s)
- Margarita Bartish
- Lady Davis Institute, Jewish General Hospital, Translational Center for Research in Cancer, McGill University, Montreal, QC, Canada
| | - Sonia V Del Rincón
- Lady Davis Institute, Jewish General Hospital, Translational Center for Research in Cancer, McGill University, Montreal, QC, Canada.,Oncology and Experimental Medicine, McGill University, Montreal, QC, Canada
| | - Christopher E Rudd
- Division of Immuno-Oncology, Research Center Maisonneuve-Rosemont Hospital, Montreal, QC, Canada.,Département de Médecine, Université de Montréal, Montreal, QC, Canada
| | - H Uri Saragovi
- Lady Davis Institute, Jewish General Hospital, Translational Center for Research in Cancer, McGill University, Montreal, QC, Canada.,Oncology and Experimental Medicine, McGill University, Montreal, QC, Canada.,Pharmacology and Therapeutics, and Ophthalmology and Vision Sciences, McGill University, Montreal, QC, Canada
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16
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Unveiling Molecular Recognition of Sialoglycans by Human Siglec-10. iScience 2020; 23:101231. [PMID: 32629603 PMCID: PMC7306591 DOI: 10.1016/j.isci.2020.101231] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/20/2020] [Accepted: 05/29/2020] [Indexed: 12/17/2022] Open
Abstract
Siglec-10 is an inhibitory I-type lectin selectively recognizing sialoglycans exposed on cell surfaces, involved in several patho-physiological processes. The key role Siglec-10 plays in the regulation of immune cell functions has made it a potential target for the development of immunotherapeutics against a broad range of diseases. However, the crystal structure of the protein has not been resolved for the time being and the atomic description of Siglec-10 interactions with complex glycans has not been previously unraveled. We present here the first insights of the molecular mechanisms regulating the interaction between Siglec-10 and naturally occurring sialoglycans. We used combined spectroscopic, computational and biophysical approaches to dissect glycans' epitope mapping and conformation upon binding in order to afford a description of the 3D complexes. Our outcomes provide a structural perspective for the rational design and development of high-affinity ligands to control the receptor functionality. We unveiled the molecular basis of sialoglycans recognition by Siglec-10 The conformation of sialoglycans drives the interaction with the protein Siglec-10 is able to recognize and bind complex N-glycans Our outcomes may open the venue for the design and development of novel glycomimetics
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17
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Discovery of a new sialic acid binding region that regulates Siglec-7. Sci Rep 2020; 10:8647. [PMID: 32457377 PMCID: PMC7250851 DOI: 10.1038/s41598-020-64887-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 04/21/2020] [Indexed: 11/11/2022] Open
Abstract
Siglec-7 is a human CD33-like siglec, and is localised predominantly on human natural killer (NK) cells and monocytes. Siglec-7 is considered to function as an immunoreceptor in a sialic acid-dependent manner. However, the underlying mechanisms linking sialic acid-binding and function remain unknown. Here, to gain new insights into the ligand-binding properties of Siglec-7, we carried out in silico analysis and site-directed mutagenesis, and found a new sialic acid-binding region (site 2 containing R67) in addition to the well-known primary ligand-binding region (site 1 containing R124). This was supported by equilibrium dialysis, STD-NMR experiments, and inhibition analysis of GD3-binding toward Siglec-7 using synthetic sialoglycoconjugates and a comprehensive set of ganglioside-based glycoconjugates. Our results suggest that the two ligand-binding sites are potentially controlled by each other due to the flexible conformation of the C-C′ loop of Siglec-7.
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18
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Tong W, Maira M, Roychoudhury R, Galan A, Brahimi F, Gilbert M, Cunningham AM, Josephy S, Pirvulescu I, Moffett S, Saragovi HU. Vaccination with Tumor-Ganglioside Glycomimetics Activates a Selective Immunity that Affords Cancer Therapy. Cell Chem Biol 2019; 26:1013-1026.e4. [DOI: 10.1016/j.chembiol.2019.03.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/19/2018] [Accepted: 03/27/2019] [Indexed: 02/06/2023]
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19
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Abstract
Sialic acid (Sia) is involved in many biological activities and commonly occurs as a monosialyl residue at the nonreducing terminal end of glycoconjugates. The loss of activity of UDP-GlcNAc2-epimerase/ManNAc kinase, which is a key enzyme in Sia biosynthesis, is lethal to the embryo, which clearly indicates the importance of Sia in embryogenesis. Occasionally, oligo/polymeric Sia structures such as disialic acid (diSia), oligosialic acid (oligoSia), and polysialic acid (polySia) occur in glycoconjugates. In particular, polySia, a well-known epitope that commonly occurs in neuroinvasive bacteria and vertebrate brains, is one of the most well-known and biologically/neurologically important glycotopes in vertebrates. The biological effects of polySia, especially on neural cell-adhesion molecules, have been well studied, and in-depth knowledge regarding polySia has been accumulated. In addition, the importance of diSia and oligoSia epitopes has been reported. In this chapter, the recent advances in the study of diSia, oligoSia, and polySia residues in glycoproteins in neurology, and their history, definition, occurrence, analytical methods, biosynthesis, and biological functions evaluated by phenotypes of gene-targeted mice, biochemical features, and related diseases are described.
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20
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Shenoy GN, Loyall J, Berenson CS, Kelleher RJ, Iyer V, Balu-Iyer SV, Odunsi K, Bankert RB. Sialic Acid-Dependent Inhibition of T Cells by Exosomal Ganglioside GD3 in Ovarian Tumor Microenvironments. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2018; 201:3750-3758. [PMID: 30446565 PMCID: PMC6289713 DOI: 10.4049/jimmunol.1801041] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 10/15/2018] [Indexed: 01/07/2023]
Abstract
The tumor microenvironment is rendered immunosuppressive by a variety of cellular and acellular factors that represent potential cancer therapeutic targets. Although exosomes isolated from ovarian tumor ascites fluids have been previously reported to induce a rapid and reversible T cell arrest, the factors present on or within exosomes that contribute to immunosuppression have not been fully defined. In this study, we establish that GD3, a ganglioside expressed on the surface of exosomes isolated from human ovarian tumor ascites fluids, is causally linked to the functional arrest of T cells activated through their TCR. This arrest is inhibited by Ab blockade of exosomal GD3 or by the removal of GD3+ exosomes. Empty liposomes expressing GD3 on the surface also inhibit the activation of T cells, establishing that GD3 contributes to the functional arrest of T cells independent of factors present in exosomes. Finally, we demonstrate that the GD3-mediated arrest of the TCR activation is dependent upon sialic acid groups, because their enzymatic removal from exosomes or liposomes results in a loss of inhibitory capacity. Collectively, these data define GD3 as a potential immunotherapeutic target.
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Affiliation(s)
- Gautam N. Shenoy
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York
| | - Jenni Loyall
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York
| | - Charles S. Berenson
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, Infectious Disease Division, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, and Department of Veteran Affairs, Western New York Health Care System, Buffalo, New York
| | - Raymond J. Kelleher
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York
| | - Vandana Iyer
- Department of Pharmaceutical Sciences, University at Buffalo, Buffalo, New York
| | - Sathy V. Balu-Iyer
- Department of Pharmaceutical Sciences, University at Buffalo, Buffalo, New York
| | - Kunle Odunsi
- Department of Gynecologic Oncology, Roswell Park Comprehensive Cancer Center, Elm and Carlton Streets, Buffalo, New York
| | - Richard B. Bankert
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York
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21
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Ledeen RW, Kopitz J, Abad-Rodríguez J, Gabius HJ. Glycan Chains of Gangliosides: Functional Ligands for Tissue Lectins (Siglecs/Galectins). PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2018; 156:289-324. [PMID: 29747818 DOI: 10.1016/bs.pmbts.2017.12.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Molecular signals on the cell surface are responsible for adhesion and communication. Of relevance in this respect, their chemical properties endow carbohydrates with the capacity to store a maximum of information in a minimum of space. One way to present glycans on the cell surface is their covalent conjugation to a ceramide anchor. Among the resulting glycosphingolipids, gangliosides are special due to the presence of at least one sialic acid in the glycan chains. Their spatial accessibility and the dynamic regulation of their profile are factors that argue in favor of a role of glycans of gangliosides as ligands (counterreceptors) for carbohydrate-binding proteins (lectins). Indeed, as discovered first for a bacterial toxin, tissue lectins bind gangliosides and mediate contact formation (trans) and signaling (cis). While siglecs have a preference for higher sialylated glycans, certain galectins also target the monosialylated pentasaccharide of ganglioside GM1. Enzymatic interconversion of ganglioside glycans by sialidase action, relevant for neuroblastoma cell differentiation and growth control in vitro, for axonogenesis and axon regeneration, as well as for proper communication between effector and regulatory T cells, changes lectin-binding affinity profoundly. The GD1a-to-GM1 "editing" is recognized by such lectins, for example, myelin-associated glycoprotein (siglec-4) losing affinity and galectin-1 gaining reactivity, and then translated into postbinding signaling. Orchestrations of loss/gain of affinity, of ganglioside/lectin expression, and of lectin presence in a network offer ample opportunities for fine-tuning. Thus glycans of gangliosides such as GD1a and GM1 are functional counterreceptors by a pairing with tissue lectins, an emerging aspect of ganglioside and lectin functionality.
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Affiliation(s)
- Robert W Ledeen
- Department of Pharmacology, Physiology & Neuroscience, Rutgers New Jersey Medical School, Newark, NJ, United States.
| | - Jürgen Kopitz
- Ruprecht-Karls-University Heidelberg, Heidelberg, Germany
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Siglec-7 restores β-cell function and survival and reduces inflammation in pancreatic islets from patients with diabetes. Sci Rep 2017; 7:45319. [PMID: 28378743 PMCID: PMC5381285 DOI: 10.1038/srep45319] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 02/22/2017] [Indexed: 01/16/2023] Open
Abstract
Chronic inflammation plays a key role in both type 1 and type 2 diabetes. Cytokine and chemokine production within the islets in a diabetic milieu results in β-cell failure and diabetes progression. Identification of targets, which both prevent macrophage activation and infiltration into islets and restore β-cell functionality is essential for effective diabetes therapy. We report that certain Sialic-acid-binding immunoglobulin-like-lectins (siglecs) are expressed in human pancreatic islets in a cell-type specific manner. Siglec-7 was expressed on β-cells and down-regulated in type 1 and type 2 diabetes and in infiltrating activated immune cells. Over-expression of Siglec-7 in diabetic islets reduced cytokines, prevented β-cell dysfunction and apoptosis and reduced recruiting of migrating monocytes. Our data suggest that restoration of human Siglec-7 expression may be a novel therapeutic strategy targeted to both inhibition of immune activation and preservation of β-cell function and survival.
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The human fetoembryonic defense system hypothesis: Twenty years on. Mol Aspects Med 2016; 51:71-88. [PMID: 27349751 DOI: 10.1016/j.mam.2016.06.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 06/13/2016] [Accepted: 06/21/2016] [Indexed: 11/21/2022]
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Gabius HJ, Manning JC, Kopitz J, André S, Kaltner H. Sweet complementarity: the functional pairing of glycans with lectins. Cell Mol Life Sci 2016; 73:1989-2016. [PMID: 26956894 PMCID: PMC11108359 DOI: 10.1007/s00018-016-2163-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 02/08/2016] [Accepted: 02/09/2016] [Indexed: 02/07/2023]
Abstract
Carbohydrates establish the third alphabet of life. As part of cellular glycoconjugates, the glycans generate a multitude of signals in a minimum of space. The presence of distinct glycotopes and the glycome diversity are mapped by sugar receptors (antibodies and lectins). Endogenous (tissue) lectins can read the sugar-encoded information and translate it into functional aspects of cell sociology. Illustrated by instructive examples, each glycan has its own ligand properties. Lectins with different folds can converge to target the same epitope, while intrafamily diversification enables functional cooperation and antagonism. The emerging evidence for the concept of a network calls for a detailed fingerprinting. Due to the high degree of plasticity and dynamics of the display of genes for lectins the validity of extrapolations between different organisms of the phylogenetic tree yet is inevitably limited.
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Affiliation(s)
- H-J Gabius
- Institute of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Veterinärstr. 13, 80539, Munich, Germany.
| | - J C Manning
- Institute of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Veterinärstr. 13, 80539, Munich, Germany
| | - J Kopitz
- Institute of Pathology, Department of Applied Tumor Biology, Ruprecht-Karls-University Heidelberg, Im Neuenheimer Feld 224, 69120, Heidelberg, Germany
| | - S André
- Institute of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Veterinärstr. 13, 80539, Munich, Germany
| | - H Kaltner
- Institute of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Veterinärstr. 13, 80539, Munich, Germany
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Abstract
Receptors expressed on the host cell surface adhere viruses to target cells and serve as determinants of viral tropism. Several viruses bind cell surface glycans to facilitate entry, but the contribution of specific glycan moieties to viral disease is incompletely understood. Reovirus provides a tractable experimental model for studies of viral neuropathogenesis. In newborn mice, serotype 1 (T1) reovirus causes hydrocephalus, whereas serotype 3 (T3) reovirus causes encephalitis. T1 and T3 reoviruses engage distinct glycans, suggesting that glycan-binding capacity contributes to these differences in pathogenesis. Using structure-guided mutagenesis, we engineered a mutant T1 reovirus incapable of binding the T1 reovirus-specific glycan receptor, GM2. The mutant virus induced substantially less hydrocephalus than wild-type virus, an effect phenocopied by wild-type virus infection of GM2-deficient mice. In comparison to wild-type virus, yields of mutant virus were diminished in cultured ependymal cells, the cell type that lines the brain ventricles. These findings suggest that GM2 engagement targets reovirus to ependymal cells in mice and illuminate the function of glycan engagement in reovirus serotype-dependent disease. Receptor utilization strongly influences viral disease, often dictating host range and target cell selection. Different reovirus serotypes bind to different glycans, but a precise function for these molecules in pathogenesis is unknown. We used type 1 (T1) reovirus deficient in binding the GM2 glycan and mice lacking GM2 to pinpoint a role for glycan engagement in hydrocephalus caused by T1 reovirus. This work indicates that engagement of a specific glycan can lead to infection of specific cells in the host and consequent disease at that site. Since reovirus is being developed as a vaccine vector and oncolytic agent, understanding reovirus-glycan interactions may allow manipulation of reovirus glycan-binding properties for therapeutic applications.
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Cognasse F, Nguyen KA, Damien P, McNicol A, Pozzetto B, Hamzeh-Cognasse H, Garraud O. The Inflammatory Role of Platelets via Their TLRs and Siglec Receptors. Front Immunol 2015; 6:83. [PMID: 25784910 PMCID: PMC4345914 DOI: 10.3389/fimmu.2015.00083] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 02/12/2015] [Indexed: 12/16/2022] Open
Abstract
Platelets are non-nucleated cells that play central roles in the processes of hemostasis, innate immunity, and inflammation; however, several reports show that these distinct functions are more closely linked than initially thought. Platelets express numerous receptors and contain hundreds of secretory products. These receptors and secretory products are instrumental to the platelet functional responses. The capacity of platelets to secrete copious amounts of cytokines, chemokines, and related molecules appears intimately related to the role of the platelet in inflammation. Platelets exhibit non-self-infectious danger detection molecules on their surfaces, including those belonging to the “toll-like receptor” family, as well as pathogen sensors of other natures (Ig- or complement receptors, etc.). These receptors permit platelets to both bind infectious agents and deliver differential signals leading to the secretion of cytokines/chemokines, under the control of specific intracellular regulatory pathways. In contrast, dysfunctional receptors or dysregulation of the intracellular pathway may increase the susceptibility to pathological inflammation. Physiological vs. pathological inflammation is tightly controlled by the sensors of danger expressed in resting, as well as in activated, platelets. These sensors, referred to as pathogen recognition receptors, primarily sense danger signals termed pathogen associated molecular patterns. As platelets are found in inflamed tissues and are involved in auto-immune disorders, it is possible that they can also be stimulated by internal pathogens. In such cases, platelets can also sense danger signals using damage associated molecular patterns (DAMPs). Some of the most significant DAMP family members are the alarmins, to which the Siglec family of molecules belongs. This review examines the role of platelets in anti-infection immunity via their TLRs and Siglec receptors.
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Affiliation(s)
- Fabrice Cognasse
- Etablissement Français du Sang Auvergne-Loire , Saint-Etienne , France ; GIMAP-EA3064, Université de Lyon , Saint Etienne , France
| | - Kim Anh Nguyen
- GIMAP-EA3064, Université de Lyon , Saint Etienne , France
| | - Pauline Damien
- GIMAP-EA3064, Université de Lyon , Saint Etienne , France
| | - Archibald McNicol
- Faculty of Health Sciences, Colleges of Pharmacy and Medicine, University of Manitoba , Winnipeg, MB , Canada
| | - Bruno Pozzetto
- GIMAP-EA3064, Université de Lyon , Saint Etienne , France
| | | | - Olivier Garraud
- GIMAP-EA3064, Université de Lyon , Saint Etienne , France ; Institut National de Transfusion Sanguine (INTS) , Paris , France
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27
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Sato C, Kitajima K. Disialic, oligosialic and polysialic acids: distribution, functions and related disease. J Biochem 2013; 154:115-36. [DOI: 10.1093/jb/mvt057] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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28
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Sotnikov I, Veremeyko T, Starossom SC, Barteneva N, Weiner HL, Ponomarev ED. Platelets recognize brain-specific glycolipid structures, respond to neurovascular damage and promote neuroinflammation. PLoS One 2013; 8:e58979. [PMID: 23555611 PMCID: PMC3608633 DOI: 10.1371/journal.pone.0058979] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 02/11/2013] [Indexed: 11/23/2022] Open
Abstract
Platelets respond to vascular damage and contribute to inflammation, but their role in the neurodegenerative diseases is unknown. We found that the systemic administration of brain lipid rafts induced a massive platelet activation and degranulation resulting in a life-threatening anaphylactic-like response in mice. Platelets were engaged by the sialated glycosphingolipids (gangliosides) integrated in the rigid structures of astroglial and neuronal lipid rafts. The brain-abundant gangliosides GT1b and GQ1b were specifically recognized by the platelets and this recognition involved multiple receptors with P-selectin (CD62P) playing the central role. During the neuroinflammation, platelets accumulated in the central nervous system parenchyma, acquired an activated phenotype and secreted proinflammatory factors, thereby triggering immune response cascades. This study determines a new role of platelets which directly recognize a neuronal damage and communicate with the cells of the immune system in the pathogenesis of neurodegenerative diseases.
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Affiliation(s)
- Ilya Sotnikov
- Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Neonatal-Perinatal Medicine, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Tatyana Veremeyko
- Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sarah C. Starossom
- Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Natalia Barteneva
- The Immune Disease Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Howard L. Weiner
- Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (EDP); (HLW)
| | - Eugene D. Ponomarev
- Center for Neurologic Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- School for Biomedical Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong
- * E-mail: (EDP); (HLW)
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29
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Heikema AP, Jacobs BC, Horst-Kreft D, Huizinga R, Kuijf ML, Endtz HP, Samsom JN, van Wamel WJB. Siglec-7 specifically recognizes Campylobacter jejuni strains associated with oculomotor weakness in Guillain-Barré syndrome and Miller Fisher syndrome. Clin Microbiol Infect 2012; 19:E106-12. [PMID: 23173866 DOI: 10.1111/1469-0691.12073] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 10/12/2012] [Accepted: 10/12/2012] [Indexed: 11/26/2022]
Abstract
Due to molecular mimicry, Campylobacter jejuni lipo-oligosaccharides can induce a cross-reactive antibody response to nerve gangliosides, which leads to Guillain-Barré syndrome (GBS). Cross-reactive antibodies to ganglioside GQ1b are strongly associated with oculomotor weakness in GBS and its variant, Miller Fisher syndrome (MFS). Antigen recognition is a crucial first step in the induction of a cross-reactive antibody response, and it has been shown that GQ1b-like epitopes expressed on the surface of C. jejuni are recognized by sialic acid-binding immunoglobulin-like lectin-7 (Siglec-7). We aimed to determine the epitope specificity of C. jejuni binding to Siglec-7, and correlate the outcome to disease symptoms in GBS and MFS patients. Using a well-defined GBS/MFS-associated C. jejuni strain collection, which included three sialic acid knockout strains, we found that Siglec-7 exclusively binds to C. jejuni strains that express terminal disialylated ganglioside mimics. When serological and diagnostic patient records were correlated with the Siglec-7-binding properties, we observed an association between Siglec-7 binding and the presence of anti-GQ1b antibodies in patient serum. In addition, Siglec-7 binding was associated with oculomotor weakness in GBS and MFS patients. Lipo-oligosaccharide-specific binding of C. jejuni to Siglec-7 may be an initiating event in immune recognition and presentation, and lead to anti-GQ1b antibody production and the development of ocular weakness in GBS or MFS.
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Affiliation(s)
- A P Heikema
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, University Medical Centre, Rotterdam, The Netherlands.
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30
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Campylobacter jejuni lipooligosaccharides modulate dendritic cell-mediated T cell polarization in a sialic acid linkage-dependent manner. Infect Immun 2011; 79:2681-9. [PMID: 21502591 DOI: 10.1128/iai.00009-11] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Carbohydrate mimicry between Campylobacter jejuni lipooligosaccharides (LOS) and host neural gangliosides plays a crucial role in the pathogenesis of Guillain-Barré syndrome (GBS). Campylobacter jejuni LOS may mimic various gangliosides, which affects the immunogenicity and the type of neurological deficits in GBS patients. Previous studies have shown the interaction of LOS with sialic acid-specific siglec receptors, although the functional consequences remain unknown. Cells that express high levels of siglecs include dendritic cells (DCs), which are crucial for initiation and differentiation of immune responses. We confirm that α2,3-sialylated GD1a/GM1a mimic and α2,8-sialylated GD1c mimic LOS structures interact with recombinant Sn and siglec-7, respectively. Although the linkage of the terminal sialic acid of LOS did not regulate expression of DC maturation markers, it displayed clear opposite expression levels of interleukin-12 (IL-12) and OX40L, molecules involved in DC-mediated Th cell differentiation. Accordingly, targeting DC-expressed siglec-7 with α2,8-linked sialylated LOS resulted in Th1 responses, whereas Th2 responses were induced by targeting with LOS containing α2,3-linked sialic acid. Thus, our data demonstrate for the first time that depending on the sialylated composition of Campylobacter jejuni LOS, specific Th differentiation programs are initiated, possibly through targeting of distinct DC-expressed siglecs.
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31
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Siglec receptors and hiding plaques in Alzheimer's disease. J Mol Med (Berl) 2009; 87:697-701. [PMID: 19390836 DOI: 10.1007/s00109-009-0472-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 04/03/2009] [Accepted: 04/15/2009] [Indexed: 01/22/2023]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease. One hallmark of this disease is the continuous increase in the numbers and size of aggregating amyloid plaques. The accumulation of extracellular plaques is an immunologically interesting phenomenon since microglial cells, brain-specific macrophages, should be able to cleanse the aggregating material from the human brain. Immunotherapy targeting beta-amyloid peptides in plaques with antibodies represents a promising therapy in AD. Recent progress in pattern recognition receptors of monocytes and macrophages has revealed that the sialic acid-binding, immunoglobulin-like lectin (Siglec) family of receptors is an important recognition receptor for sialylated glycoproteins and glycolipids. Interestingly, recent studies have revealed that microglial cells contain only one type of Siglec receptors, Siglec-11, which mediates immunosuppressive signals and thus inhibits the function of other microglial pattern recognition receptors, such as TLRs, NLRs, and RAGE receptors. We will review here the recent literature which clearly indicates that aggregating amyloid plaques are masked in AD by sialylated glycoproteins and gangliosides. Sialylation and glycosylation of plaques, mimicking the cell surface glycocalyx, can activate the immunosuppressive Siglec-11 receptors, as well as hiding the neuritic plaques, allowing them to evade the immune surveillance of microglial cells. This kind of immune evasion can prevent the microglial cleansing process of aggregating amyloid plaques in AD.
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32
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Ravindranath MH, Yesowitch P, Sumobay C, Morton DL. Glycoimmunomics of human cancer: current concepts and future perspectives. Future Oncol 2007; 3:201-14. [PMID: 17381420 DOI: 10.2217/14796694.3.2.201] [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: 11/21/2022] Open
Abstract
Future strategies for the treatment of human cancer require a full appreciation of the intracellular and extracellular changes that accompany neoplastic transformation. The changes may involve a variety of micro- and macro-molecules, including, but not restricted to, peptides, proteins (with sugar and/or lipid moieties), oligosaccharides, glycolipids (neutral or acidic, e.g., gangliosides), ceramides, fatty acids and other lipids. Although several therapeutic approaches have been well developed in recent years, most of the reported studies focus on proteins and peptides. Glycoantigens and lipoantigens have been neglected. Elucidation of the profiles and properties of all molecules associated with tumor progression is required to develop a successful strategy to treat human cancer. This review describes the unique immunomics of tumor-associated glycoantigens and explains why the field of glycoimmunomics may yield clinically important biomarkers and treatments for the management of human cancer.
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Affiliation(s)
- Mepur H Ravindranath
- Department of Glycoimmunotherapy, John Wayne Cancer Institute, Saint John's Health Center, Santa Monica, CA 90404-2302, USA.
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Attrill H, Imamura A, Sharma RS, Kiso M, Crocker PR, van Aalten DMF. Siglec-7 undergoes a major conformational change when complexed with the alpha(2,8)-disialylganglioside GT1b. J Biol Chem 2006; 281:32774-83. [PMID: 16895906 DOI: 10.1074/jbc.m601714200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The siglecs are a group of mammalian sialic acid binding receptors expressed predominantly in the immune system. The CD33-related siglecs show complex recognition patterns for sialylated glycans. Siglec-7 shows a preference for alpha(2,8)-disialylated ligands and provides a structural template for studying the key interactions that drive this selectivity. We have co-crystallized Siglec-7 with a synthetic oligosaccharide corresponding to the alpha(2,8)-disialylated ganglioside GT1b. The crystal structure of the complex offers a first glimpse into how this important family of lectins binds the structurally diverse gangliosides. The structure reveals that the C-C' loop, a region implicated in previous studies as driving siglec specificity, undergoes a dramatic conformational shift, allowing it to interact with the underlying neutral glycan core of the ganglioside. The structural data in combination with mutagenesis studies show that binding of the ganglioside is driven by extensive hydrophobic contacts together with key polar interactions and that the binding site structure is complementary to preferred solution conformations of GT1b.
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Affiliation(s)
- Helen Attrill
- Division of Biological Chemistry and Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
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34
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Avril T, North SJ, Haslam SM, Willison HJ, Crocker PR. Probing the cis interactions of the inhibitory receptor Siglec-7 with alpha2,8-disialylated ligands on natural killer cells and other leukocytes using glycan-specific antibodies and by analysis of alpha2,8-sialyltransferase gene expression. J Leukoc Biol 2006; 80:787-96. [PMID: 16857734 DOI: 10.1189/jlb.1005559] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Siglec-7 is a CD33-related sialic acid-binding Ig-like lectin expressed strongly on NK cells, where it can function as an inhibitory receptor. Its sialic acid-binding activity on NK cells is masked by cis interactions with sialylated glycans, which are likely to be important for regulating the inhibitory function of Siglec-7, which exhibits an unusual preference for alpha2,8-linked disialic acids, a motif found in "b-series" gangliosides and some glycoproteins. To investigate the presence of alpha2,8-linked disialic acids on NK cells, T cells, monocytes, and B cells, we first analyzed their expression of all known alpha2,8-sialyltransferase genes by quantitative PCR. Unlike T cells, B cells, and monocytes, NK cells consistently expressed mRNA encoding ST8Sia VI, which creates alpha2,8-linked disialic acids on O-linked glycans of glycoproteins. All blood leukocytes expressed ST8Sia IV, implicated in polysialic acid synthesis, and NK cells variably expressed high levels of ST8Sia V mRNA required for GT3 expression. Two human IgM antibodies, Ha1 and Pi1, with specificity for the alpha2,8-disialyl motif reacted strongly with NK cells in a sialic acid-dependent manner and less strongly with T cells and monocytes. Antibody-induced clustering of Siglec-7 on NK cells resulted in partial colocalization with anti-Ha1. Finally, MALDI-TOF mass spectrometric analysis of isolated NK cell O-glycans revealed the presence of a peak at mass-to-charge ratio of 1619.4 mass units, corresponding to a putative alpha2,8-disialylated glycan. Together, these results suggest that NK cells are decorated with alpha2,8-disialic acid structures implicated in regulation of cellular activation via interactions with Siglec-7.
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MESH Headings
- Animals
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/immunology
- Antigens, Differentiation, Myelomonocytic/immunology
- Antigens, Differentiation, Myelomonocytic/metabolism
- Cell Line, Tumor
- Gene Expression Profiling
- Humans
- Killer Cells, Natural/immunology
- Lectins/immunology
- Lectins/metabolism
- Leukocytes/immunology
- Leukocytes, Mononuclear/enzymology
- Leukocytes, Mononuclear/immunology
- Ligands
- Mice
- Polysaccharides/chemistry
- Polysaccharides/immunology
- RNA, Messenger/genetics
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Sensitivity and Specificity
- Sialic Acids/chemistry
- Sialic Acids/metabolism
- Sialyltransferases/biosynthesis
- Sialyltransferases/genetics
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods
- Stereoisomerism
- Structure-Activity Relationship
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Affiliation(s)
- Tony Avril
- Wellcome Trust Biocentre, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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35
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von Gunten S, Simon HU. Sialic acid binding immunoglobulin-like lectins may regulate innate immune responses by modulating the life span of granulocytes. FASEB J 2006; 20:601-5. [PMID: 16581967 DOI: 10.1096/fj.05-5401hyp] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The regulation of cell death is a key element in building up and maintaining both innate and adaptive immunity. A critical role in this process plays the tumor necrosis factor (TNF)/nerve growth factor (NGF) receptor family of death receptors. Recent work suggests that sialic acid binding immunoglobulin (Ig) -like lectins (Siglecs) are also empowered to transmit death signals, at least into myeloid cells. Strikingly, death induction by Siglecs is enhanced when cells are exposed to proinflammatory survival cytokines. Based on these recent insights, we hypothesize that at least some members of the Siglec family regulate immune responses via the activation of caspase-dependent and caspase-independent cell death pathways.
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36
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Abstract
Animal glycan-recognizing proteins can be broadly classified into two groups-lectins (which typically contain an evolutionarily conserved carbohydrate-recognition domain [CRD]) and sulfated glycosaminoglycan (SGAG)-binding proteins (which appear to have evolved by convergent evolution). Proteins other than antibodies and T-cell receptors that mediate glycan recognition via immunoglobulin (Ig)-like domains are called "I-type lectins." The major homologous subfamily of I-type lectins with sialic acid (Sia)-binding properties and characteristic amino-terminal structural features are called the "Siglecs" (Sia-recognizing Ig-superfamily lectins). The Siglecs can be divided into two groups: an evolutionarily conserved subgroup (Siglecs-1, -2, and -4) and a CD33/Siglec-3-related subgroup (Siglecs-3 and -5-13 in primates), which appear to be rapidly evolving. This article provides an overview of historical and current information about the Siglecs.
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Affiliation(s)
- Ajit Varki
- Research Center for Glycoscience, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, Japan.
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37
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Bochner BS, Alvarez RA, Mehta P, Bovin NV, Blixt O, White JR, Schnaar RL. Glycan array screening reveals a candidate ligand for Siglec-8. J Biol Chem 2004; 280:4307-12. [PMID: 15563466 DOI: 10.1074/jbc.m412378200] [Citation(s) in RCA: 208] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Sialic acid-binding immunoglobulin-like lectin 8 (Siglec-8) is selectively expressed on human eosinophils, basophils, and mast cells, where it regulates their function and survival. Previous studies demonstrated sialic acid-dependent binding of Siglec-8 but failed to reveal significant substructure specificity or high affinity of that binding. To test a broader range of potential ligands, a Siglec-8-Ig chimeric protein was tested for binding to 172 different glycan structures immobilized as biotinylated glycosides on a 384-well streptavidin-coated plate. Of these, approximately 40 structures were sialylated. Among these, avid binding was detected to a single defined glycan, NeuAcalpha2-3(6-O-sulfo)Galbeta1-4[Fucalpha1-3]GlcNAc, also referred to in the literature as 6'-sulfo-sLex. Notably, neither unsulfated sLex (NeuAcalpha2-3Galbeta1-4[Fucalpha1-3]GlcNAc) nor an isomer with the sulfate on the 6-position of the GlcNAc residue (6-sulfo-sLex, NeuAcalpha2-3Galbeta1-4[Fucalpha1-3](6-O-sulfo)GlcNAc) supported detectable binding. Subsequent secondary screening was performed using surface plasmon resonance. Biotin glycosides immobilized on streptavidin biosensor chips were exposed to Siglec-8-Ig in solution. Whereas surfaces derivatized with sLex and 6-sulfo-sLex failed to support detectable Siglec-8 binding, 6'-sulfo-sLex supported significant binding with a Kd of 2.3 microm. In a separate test of binding specificity, aminopropyl glycosides were covalently immobilized at different concentrations on activated (N-hydroxysuccinimidyl) glass surfaces (Schott-Nexterion Slide H). Subsequent exposure to Siglec-8-Ig precomplexed with fluorescein isothiocyanate anti-human Fc resulted in fluorescent signals at immobilized concentrations of 6'-sulfo-sLex of <5 pmol/spot. In contrast, sLex and 6-sulfo-sLex did not support any Siglec-8 binding at the highest concentration tested (300 pmol/spot). We conclude that Siglec-8 binds preferentially to the sLex structure bearing an additional sulfate ester on the galactose 6-hydroxyl.
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Affiliation(s)
- Bruce S Bochner
- Division of Allergy and Clinical Immunology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224, USA.
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38
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Swaminathan CP, Wais N, Vyas VV, Velikovsky CA, Moretta A, Moretta L, Biassoni R, Mariuzza RA, Dimasi N. Entropically Assisted Carbohydrate Recognition by a Natural Killer Cell-Surface Receptor. Chembiochem 2004; 5:1571-5. [PMID: 15515091 DOI: 10.1002/cbic.200400130] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Chittoor P Swaminathan
- Center for Advanced Research in Biotechnology, W. M. Keck Laboratory for Structural Biology, University of Maryland Biotechnology Institute, 9600 Gudelsky Drive, Rockville, Maryland 20850, USA
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