1
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Atxabal U, Nycholat C, Pröpster JM, Fernández A, Oyenarte I, Lenza MP, Franconetti A, Soares CO, Coelho H, Marcelo F, Schubert M, Paulson JC, Jiménez-Barbero J, Ereño-Orbea J. Unraveling Molecular Recognition of Glycan Ligands by Siglec-9 via NMR Spectroscopy and Molecular Dynamics Modeling. ACS Chem Biol 2024; 19:483-496. [PMID: 38321945 PMCID: PMC10877568 DOI: 10.1021/acschembio.3c00664] [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: 10/30/2023] [Revised: 01/09/2024] [Accepted: 01/16/2024] [Indexed: 02/08/2024]
Abstract
Human sialic-acid-binding immunoglobulin-like lectin-9 (Siglec-9) is a glycoimmune checkpoint receptor expressed on several immune cells. Binding of Siglec-9 to sialic acid containing glycans (sialoglycans) is well documented to modulate its functions as an inhibitory receptor. Here, we first assigned the amino acid backbone of the Siglec-9 V-set domain (Siglec-9d1), using well-established triple resonance three-dimensional nuclear magnetic resonance (NMR) methods. Then, we combined solution NMR and molecular dynamic simulation methods to decipher the molecular details of the interaction of Siglec-9 with the natural ligands α2,3 and α2,6 sialyl lactosamines (SLN), sialyl Lewis X (sLeX), and 6-O sulfated sLeX and with two synthetically modified sialoglycans that bind with high affinity. As expected, Neu5Ac is accommodated between the F and G β-strands at the canonical sialic acid binding site. Addition of a heteroaromatic scaffold 9N-5-(2-methylthiazol-4-yl)thiophene sulfonamide (MTTS) at the C9 position of Neu5Ac generates new interactions with the hydrophobic residues located at the G-G' loop and the N-terminal region of Siglec-9. Similarly, the addition of the aromatic substituent (5-N-(1-benzhydryl-1H-1,2,3-triazol-4-yl)methyl (BTC)) at the C5 position of Neu5Ac stabilizes the conformation of the long and flexible B'-C loop present in Siglec-9. These results expose the underlying mechanism responsible for the enhanced affinity and specificity for Siglec-9 for these two modified sialoglycans and sheds light on the rational design of the next generation of modified sialoglycans targeting Siglec-9.
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Affiliation(s)
- Unai Atxabal
- Chemical
Glycobiology Lab, Center for Cooperative Research in Biosciences (CIC
bioGUNE), Basque Research and Technology
Alliance (BRTA), 48160 Derio, Bizkaia, Spain
| | - Corwin Nycholat
- Departments
of Molecular Medicine and Immunology and Microbiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Johannes M. Pröpster
- Institute
of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Andrea Fernández
- Chemical
Glycobiology Lab, Center for Cooperative Research in Biosciences (CIC
bioGUNE), Basque Research and Technology
Alliance (BRTA), 48160 Derio, Bizkaia, Spain
| | - Iker Oyenarte
- Chemical
Glycobiology Lab, Center for Cooperative Research in Biosciences (CIC
bioGUNE), Basque Research and Technology
Alliance (BRTA), 48160 Derio, Bizkaia, Spain
| | - Maria Pia Lenza
- Chemical
Glycobiology Lab, Center for Cooperative Research in Biosciences (CIC
bioGUNE), Basque Research and Technology
Alliance (BRTA), 48160 Derio, Bizkaia, Spain
| | - Antonio Franconetti
- Chemical
Glycobiology Lab, Center for Cooperative Research in Biosciences (CIC
bioGUNE), Basque Research and Technology
Alliance (BRTA), 48160 Derio, Bizkaia, Spain
| | - Cátia O. Soares
- Associate
Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School
of Science and Technology, Universidade
NOVA de Lisboa, 2829-516 Caparica, Portugal
- UCIBIO,
Department of Chemistry, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - Helena Coelho
- Associate
Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School
of Science and Technology, Universidade
NOVA de Lisboa, 2829-516 Caparica, Portugal
- UCIBIO,
Department of Chemistry, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - Filipa Marcelo
- Associate
Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School
of Science and Technology, Universidade
NOVA de Lisboa, 2829-516 Caparica, Portugal
- UCIBIO,
Department of Chemistry, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - Mario Schubert
- Institute
of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
- Department
of Biosciences and Molecular Biology, University
of Salzburg, Hellbrunnerstrasse
34, 5020 Salzburg, Austria
| | - James C. Paulson
- Departments
of Molecular Medicine and Immunology and Microbiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Jesús Jiménez-Barbero
- Chemical
Glycobiology Lab, Center for Cooperative Research in Biosciences (CIC
bioGUNE), Basque Research and Technology
Alliance (BRTA), 48160 Derio, Bizkaia, Spain
- Ikerbasque,
Basque Foundation for Science, Euskadi Pl., 5, 48009 Bilbao, Biscay, Spain
- Department
of Organic and Inorganic Chemistry, Faculty of Science and Technology, University of the Basque Country, EHU-UPV, 48940 Leioa, Bizkaia, Spain
- Centro
de Investigacion Biomedica en Red de Enfermedades Respiratorias, Av. Monforte de Lemos, 3-5, Pabellón
11, Planta 0, 28029 Madrid, Spain
| | - June Ereño-Orbea
- Chemical
Glycobiology Lab, Center for Cooperative Research in Biosciences (CIC
bioGUNE), Basque Research and Technology
Alliance (BRTA), 48160 Derio, Bizkaia, Spain
- Ikerbasque,
Basque Foundation for Science, Euskadi Pl., 5, 48009 Bilbao, Biscay, Spain
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2
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Babulic JL, Kofsky JM, Boddington ME, Kim Y, Leblanc EV, Cook MG, Garnier CR, Emberley-Korkmaz S, Colpitts CC, Capicciotti CJ. One-Step Selective Labeling of Native Cell Surface Sialoglycans by Exogenous α2,8-Sialylation. ACS Chem Biol 2023; 18:2418-2429. [PMID: 37934063 DOI: 10.1021/acschembio.3c00475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
Exo-enzymatic glycan labeling strategies have emerged as versatile tools for efficient and selective installation of terminal glyco-motifs onto live cell surfaces. Through employing specific enzymes and nucleotide-sugar probes, cells can be equipped with defined glyco-epitopes for modulating cell function or selective visualization and enrichment of glycoconjugates. Here, we identifyCampylobacter jejunisialyltransferase Cst-II I53S as a tool for cell surface glycan modification, expanding the exo-enzymatic labeling toolkit to include installation of α2,8-disialyl epitopes. Labeling with Cst-II was achieved with biotin- and azide-tagged CMP-Neu5Ac derivatives on a model glycoprotein and native sialylated cell surface glycans across a panel of cell lines. The introduction of modified Neu5Ac derivatives onto cells by Cst-II was also retained on the surface for 6 h. By examining the specificity of Cst-II on cell surfaces, it was revealed that the α2,8-sialyltransferase primarily labeled N-glycans, with O-glycans labeled to a lesser extent, and there was an apparent preference for α2,3-linked sialosides on cells. This approach thus broadens the scope of tools for selective exo-enzymatic labeling of native sialylated glycans and is highly amenable for the construction of cell-based arrays.
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Affiliation(s)
- Jonathan L Babulic
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston K7L 3N6, Canada
| | - Joshua M Kofsky
- Department of Chemistry, Queen's University, Kingston K7L 3N6, Canada
| | - Marie E Boddington
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston K7L 3N6, Canada
| | - Youjin Kim
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston K7L 3N6, Canada
| | - Emmanuelle V Leblanc
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston K7L 3N6, Canada
| | - Madeleine G Cook
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston K7L 3N6, Canada
| | - Cole R Garnier
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston K7L 3N6, Canada
| | - Sophie Emberley-Korkmaz
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston K7L 3N6, Canada
| | - Che C Colpitts
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston K7L 3N6, Canada
| | - Chantelle J Capicciotti
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston K7L 3N6, Canada
- Department of Chemistry, Queen's University, Kingston K7L 3N6, Canada
- Department of Surgery, Queen's University, Kingston K7L 3N6, Canada
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3
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Frank M, Kuhfeldt E, Cramer J, Watzl C, Prescher H. Synthesis and Binding Mode Predictions of Novel Siglec-7 Ligands. J Med Chem 2023; 66:14315-14334. [PMID: 37793071 DOI: 10.1021/acs.jmedchem.3c01349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
Siglec-7 regulates immune cell activity and is a promising target for immunomodulation. Here, we report the discovery of novel sialic acid derivatives binding to Siglec-7. Synthesis and affinity measurements are complemented by high-quality models of sialoside-Siglec-7 complexes based on molecular dynamics (MD) simulations on the microsecond time scale. We provide details for the predicted binding modes for the new ligands, e.g., that an extension of the carbon backbone leads to a different molecular interaction pattern with the receptor and the nearby water structure than found for known Siglec-7 ligands. Further on, we uncover some shortcomings of the GLYCAM06 and GAFF2 force fields when used for the simulation of sialoside-based glycomimetics. Our results open new opportunities for the rational design of Siglec-7 inhibitors. In addition, we provide strategies on how to use and visualize MD simulations to describe and investigate sialoside-Siglec complexes in general.
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Affiliation(s)
- Martin Frank
- Molecular Structure Analysis Core Facility-W160, German Cancer Research Center, 69120 Heidelberg, Germany
- Biognos AB, Generatorsgatan 1, 40274 Göteborg, Sweden
| | | | - Jonathan Cramer
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-University of Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Carsten Watzl
- Institute of Immunology, University of Heidelberg, 69120 Heidelberg, Germany
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4
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Wang Y, Peng Y, Long R, Shi P, Zhang Y, Kong DX, Zheng J, Wang X. Sequence variety in the CC' loop of Siglec-8/9/3 determines the recognitions to sulfated oligosaccharides. Comput Struct Biotechnol J 2023; 21:4159-4171. [PMID: 37675287 PMCID: PMC10477811 DOI: 10.1016/j.csbj.2023.08.014] [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: 04/18/2023] [Revised: 08/18/2023] [Accepted: 08/18/2023] [Indexed: 09/08/2023] Open
Abstract
Siglecs are important lectins found in different types of immune cells and function as regulatory molecules by recognizing self-associated glycans and converting extracellular interactions into signals for inhibiting immune cell functions. Although many Siglecs have been found to show broad specificities and recognize different types of sulfated oligosaccharides, Siglec-8 and Siglec-9 displayed a high degree of specificity for sialyl N-acetyllactosamine (sLacNAc) with sulfations at O6-positions of the galactose (6'-sulfation) and N-acetylglucosamine (6-sulfation), respectively. Siglec-3 was recently discovered to bind sLacNAc both sulfations. In addition to a conserved arginine residue for binding to sialic acid residue, the sequence variety in the CC' loop may provide binding specificities to sulfated oligosaccharides in Siglecs. Thus, the present study employed molecular models to study the impact of different residues in the CC' loops of Siglec-8/9/3 to the recognitions of 6-sulfations in Gal and/or GlcNAc of sLacNAc. The negatively charged residues in the CC' loop of Siglec-9 formed unfavorable electrostatic repulsions with the 6-sulfate in Gal and resulted no recognitions, in contrast to the favorable interactions formed between the positively charged residues in the CC' loop of Siglec-8 and the 6-sulfate in Gal resulting strong specificity. A two-state binding model was proposed for Siglec-3 recognizing 6-sulfations in Gal and GlcNAc of sLacNAc, as the neutral residues in the CC' loop of Siglec-3 could not form strong favorable interactions to lock the 6-sulfate in Gal within a single binding pose or strong unfavorable interactions to repel the 6-sulfate in Gal. The oligosaccharide adopted two distinctive binding poses and oriented the sulfate groups to form interactions with residues in the CC' loop and G-strand. The present study provided a structural mechanism for the sequence variety in the CC' loop of Siglec-8/9/3 determining the recognitions to the sulfated oligosaccharides and offered insights into the binding specificities for Siglecs.
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Affiliation(s)
- Yucheng Wang
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Yujie Peng
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Rui Long
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Peiting Shi
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Yinghao Zhang
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - De-Xin Kong
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Jinshui Zheng
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Xiaocong Wang
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, Hubei 430070, China
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5
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Leusmann S, Ménová P, Shanin E, Titz A, Rademacher C. Glycomimetics for the inhibition and modulation of lectins. Chem Soc Rev 2023; 52:3663-3740. [PMID: 37232696 PMCID: PMC10243309 DOI: 10.1039/d2cs00954d] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Indexed: 05/27/2023]
Abstract
Carbohydrates are essential mediators of many processes in health and disease. They regulate self-/non-self- discrimination, are key elements of cellular communication, cancer, infection and inflammation, and determine protein folding, function and life-times. Moreover, they are integral to the cellular envelope for microorganisms and participate in biofilm formation. These diverse functions of carbohydrates are mediated by carbohydrate-binding proteins, lectins, and the more the knowledge about the biology of these proteins is advancing, the more interfering with carbohydrate recognition becomes a viable option for the development of novel therapeutics. In this respect, small molecules mimicking this recognition process become more and more available either as tools for fostering our basic understanding of glycobiology or as therapeutics. In this review, we outline the general design principles of glycomimetic inhibitors (Section 2). This section is then followed by highlighting three approaches to interfere with lectin function, i.e. with carbohydrate-derived glycomimetics (Section 3.1), novel glycomimetic scaffolds (Section 3.2) and allosteric modulators (Section 3.3). We summarize recent advances in design and application of glycomimetics for various classes of lectins of mammalian, viral and bacterial origin. Besides highlighting design principles in general, we showcase defined cases in which glycomimetics have been advanced to clinical trials or marketed. Additionally, emerging applications of glycomimetics for targeted protein degradation and targeted delivery purposes are reviewed in Section 4.
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Affiliation(s)
- Steffen Leusmann
- Chemical Biology of Carbohydrates (CBCH), Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research, 66123 Saarbrücken, Germany.
- Department of Chemistry, Saarland University, 66123 Saarbrücken, Germany
- Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany
| | - Petra Ménová
- University of Chemistry and Technology, Prague, Technická 5, 16628 Prague 6, Czech Republic
| | - Elena Shanin
- Department of Pharmaceutical Sciences, University of Vienna, Josef-Holaubek-Platz 2, 1090 Vienna, Austria.
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, Biocenter 5, 1030 Vienna, Austria
| | - Alexander Titz
- Chemical Biology of Carbohydrates (CBCH), Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research, 66123 Saarbrücken, Germany.
- Department of Chemistry, Saarland University, 66123 Saarbrücken, Germany
- Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany
| | - Christoph Rademacher
- Department of Pharmaceutical Sciences, University of Vienna, Josef-Holaubek-Platz 2, 1090 Vienna, Austria.
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, Biocenter 5, 1030 Vienna, Austria
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6
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van Houtum EJH, Kers-Rebel ED, Looman MW, Hooijberg E, Büll C, Granado D, Cornelissen LAM, Adema GJ. Tumor cell-intrinsic and tumor microenvironmental conditions co-determine signaling by the glycoimmune checkpoint receptor Siglec-7. Cell Mol Life Sci 2023; 80:169. [PMID: 37253806 DOI: 10.1007/s00018-023-04816-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/12/2023] [Accepted: 05/21/2023] [Indexed: 06/01/2023]
Abstract
Tumors create an immunosuppressive tumor microenvironment by altering protein expression, but also by changing their glycosylation status, like altered expression of sialoglycans. Sialoglycans are capped with sialic acid sugar residues and are recognized by Siglec immune receptors. Siglec-7 is an inhibitory immune receptor similar to PD-1, and is emerging as glycoimmune checkpoint exploited by cancer cells to evade the immune system. However, the exact cellular and molecular conditions required for Siglec-7-mediated immune cell inhibition remain largely unknown. Here, we report on the development of a chimeric Siglec-7 cell system that enables dissection of Siglec-7 signaling, rather than Siglec-7 binding. Antibody-induced clustering, sialic acid-containing polymers, and highly sialylated erythrocytes effectively induced Siglec-7 signaling, thereby validating functionality of this reporter system. Moreover, the system reveals tumor cell-dependent Siglec-7 signaling. Tumor-associated conditions important for Siglec-7 signaling were defined, such as Siglec-7 ligand expression levels, presence of the known Siglec-7 ligand CD43, and sialic acid availability for sialylation of glycans. Importantly, therapeutic targeting of the Siglec-7/sialic acid axis using a sialyltransferase inhibitor resulted in strong reduction of Siglec-7 signaling. In conclusion, using a newly established cellular tool, we defined a set of tumor-associated conditions that influence Siglec-7 signaling. Moreover, the system allows to assess the efficacy of novel cancer drugs interfering with the Siglec-7/sialic acid axis as immunotherapy to treat cancer.
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Affiliation(s)
- Eline J H van Houtum
- Radiotherapy & OncoImmunology Laboratory, Department of Radiation Oncology, Radboud University Medical Center, Post 874, 6525 GA, Nijmegen, The Netherlands
| | - Esther D Kers-Rebel
- Radiotherapy & OncoImmunology Laboratory, Department of Radiation Oncology, Radboud University Medical Center, Post 874, 6525 GA, Nijmegen, The Netherlands
| | - Maaike W Looman
- Radiotherapy & OncoImmunology Laboratory, Department of Radiation Oncology, Radboud University Medical Center, Post 874, 6525 GA, Nijmegen, The Netherlands
| | - Erik Hooijberg
- Department of Pathology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Christian Büll
- Department of Biomolecular Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Daniel Granado
- Radiotherapy & OncoImmunology Laboratory, Department of Radiation Oncology, Radboud University Medical Center, Post 874, 6525 GA, Nijmegen, The Netherlands
| | - Lenneke A M Cornelissen
- Radiotherapy & OncoImmunology Laboratory, Department of Radiation Oncology, Radboud University Medical Center, Post 874, 6525 GA, Nijmegen, The Netherlands
| | - Gosse J Adema
- Radiotherapy & OncoImmunology Laboratory, Department of Radiation Oncology, Radboud University Medical Center, Post 874, 6525 GA, Nijmegen, The Netherlands.
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7
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Gonzalez-Gil A, Li TA, Kim J, Schnaar RL. Human sialoglycan ligands for immune inhibitory Siglecs. Mol Aspects Med 2023; 90:101110. [PMID: 35965135 DOI: 10.1016/j.mam.2022.101110] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 02/08/2023]
Abstract
Most human Siglecs (sialic acid binding immunoglobulin-like lectins) are expressed on the surfaces of overlapping subsets of immune cells, and most carry immunoreceptor tyrosine-based inhibitory domains on their intracellular motifs. When immune inhibitory Siglecs bind to complementary sialoglycans in their local milieu, engagement results in down-regulation of the immune response. Siglecs have come under scrutiny as potential targets of drugs to modify the course of inflammation (and other immune system responses) and as immune checkpoints in cancer. Human Siglecs bind to endogenous human sialoglycans. The identities of these endogenous human sialoglycan immune regulators are beginning to emerge, along with some general principles that may inform future investigations in this area. Among these principles is the finding that a cell type or tissue may express a ligand for a particular Siglec on a single or a very few of its sialoglycoproteins. The selected protein carrier for a particular Siglec may be unique in a certain tissue, but vary tissue-to-tissue. The binding affinity of endogenous Siglec ligands may surpass that of its binding to synthetic sialoglycan determinants by several orders of magnitude. Since most human Siglecs have evolved rapidly and are distinct from those in most other mammals, this review describes endogenous human Siglec ligands for several human immune inhibitory Siglecs. As the identities of these immune regulatory sialoglycan ligands are defined, additional opportunities to target Siglecs therapeutically may emerge.
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Affiliation(s)
- Anabel Gonzalez-Gil
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - T August Li
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Jean Kim
- Department Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA; Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA.
| | - Ronald L Schnaar
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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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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Genetically encoded chemical crosslinking of carbohydrate. Nat Chem 2023; 15:33-42. [PMID: 36216893 PMCID: PMC9840686 DOI: 10.1038/s41557-022-01059-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 09/02/2022] [Indexed: 01/17/2023]
Abstract
Protein-carbohydrate interactions play important roles in various biological processes, such as organism development, cancer metastasis, pathogen infection and immune response, but they remain challenging to study and exploit due to their low binding affinity and non-covalent nature. Here we site-specifically engineered covalent linkages between proteins and carbohydrates under biocompatible conditions. We show that sulfonyl fluoride reacts with glycans via a proximity-enabled reactivity, and to harness this a bioreactive unnatural amino acid (SFY) that contains sulfonyl fluoride was genetically encoded into proteins. SFY-incorporated Siglec-7 crosslinked with its sialoglycan ligand specifically in vitro and on the surface of cancer cells. Through irreversible cloaking of sialoglycan at the cancer cell surface, SFY-incorporated Siglec-7 enhanced the killing of cancer cells by natural killer cells. Genetically encoding the chemical crosslinking of proteins to carbohydrates (GECX-sugar) offers a solution to address the low affinity and weak strength of protein-sugar interactions.
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10
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Forgione RE, Nieto FF, Di Carluccio C, Milanesi F, Fruscella M, Papi F, Nativi C, Molinaro A, Palladino P, Scarano S, Minunni M, Montefiori M, Civera M, Sattin S, Francesconi O, Marchetti R, Silipo A. Conformationally Constrained Sialyl Analogues as New Potential Binders of h-CD22. Chembiochem 2022; 23:e202200076. [PMID: 35313057 PMCID: PMC9315041 DOI: 10.1002/cbic.202200076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/19/2022] [Indexed: 11/21/2022]
Abstract
Here, two conformationally constrained sialyl analogues were synthesized and characterized in their interaction with the inhibitory Siglec, human CD22 (h‐CD22). An orthogonal approach, including biophysical assays (SPR and fluorescence), ligand‐based NMR techniques, and molecular modelling, was employed to disentangle the interaction mechanisms at a molecular level. The results showed that the Sialyl‐TnThr antigen analogue represents a promising scaffold for the design of novel h‐CD22 inhibitors. Our findings also suggest that the introduction of a biphenyl moiety at position 9 of the sialic acid hampers canonical accommodation of the ligand in the protein binding pocket, even though the affinity with respect to the natural ligand is increased. Our results address the search for novel modifications of the Neu5Ac‐α(2‐6)‐Gal epitope, outline new insights for the design and synthesis of high‐affinity h‐CD22 ligands, and offer novel prospects for therapeutic intervention to prevent autoimmune diseases and B‐cell malignancies.
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Affiliation(s)
- Rosa Ester Forgione
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, 80126, Napoli, Italy
| | - Ferran Fabregat Nieto
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, 80126, Napoli, Italy
| | - Cristina Di Carluccio
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, 80126, Napoli, Italy
| | - Francesco Milanesi
- Department of Chemistry "Ugo Schiff", University of Florence, Polo Scientifico e Tecnologico, 50019, Sesto Fiorentino, Firenze, Italy.,Centro Risonanze Magnetiche, CERM, Via L. Sacconi 6, 50019 Sesto Fiorentino, Firenze, Italy
| | - Martina Fruscella
- Department of Chemistry "Ugo Schiff", University of Florence, Polo Scientifico e Tecnologico, 50019, Sesto Fiorentino, Firenze, Italy
| | - Francesco Papi
- Department of Chemistry "Ugo Schiff", University of Florence, Polo Scientifico e Tecnologico, 50019, Sesto Fiorentino, Firenze, Italy
| | - Cristina Nativi
- Department of Chemistry "Ugo Schiff", University of Florence, Polo Scientifico e Tecnologico, 50019, Sesto Fiorentino, Firenze, Italy
| | - Antonio Molinaro
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, 80126, Napoli, Italy
| | - Pasquale Palladino
- Department of Chemistry "Ugo Schiff", University of Florence, Polo Scientifico e Tecnologico, 50019, Sesto Fiorentino, Firenze, Italy
| | - Simona Scarano
- Department of Chemistry "Ugo Schiff", University of Florence, Polo Scientifico e Tecnologico, 50019, Sesto Fiorentino, Firenze, Italy
| | - Maria Minunni
- Department of Chemistry "Ugo Schiff", University of Florence, Polo Scientifico e Tecnologico, 50019, Sesto Fiorentino, Firenze, Italy
| | - Marco Montefiori
- Dipartimento di Chimica, Università degli Studi di Milano, via C. Golgi, 19, 20133, Milano, Italy
| | - Monica Civera
- Dipartimento di Chimica, Università degli Studi di Milano, via C. Golgi, 19, 20133, Milano, Italy
| | - Sara Sattin
- Dipartimento di Chimica, Università degli Studi di Milano, via C. Golgi, 19, 20133, Milano, Italy
| | - Oscar Francesconi
- Department of Chemistry "Ugo Schiff", University of Florence, Polo Scientifico e Tecnologico, 50019, Sesto Fiorentino, Firenze, Italy
| | - Roberta Marchetti
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, 80126, Napoli, Italy
| | - Alba Silipo
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, 80126, Napoli, Italy
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11
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van Houtum EJH, Büll C, Cornelissen LAM, Adema GJ. Siglec Signaling in the Tumor Microenvironment. Front Immunol 2021; 12:790317. [PMID: 34966391 PMCID: PMC8710542 DOI: 10.3389/fimmu.2021.790317] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 11/23/2021] [Indexed: 12/16/2022] Open
Abstract
Sialic acid-binding immunoglobulin-like lectins (Siglecs) are a family of receptors that recognize sialoglycans - sialic acid containing glycans that are abundantly present on cell membranes. Siglecs are expressed on most immune cells and can modulate their activity and function. The majority of Siglecs contains immune inhibitory motifs comparable to the immune checkpoint receptor PD-1. In the tumor microenvironment (TME), signaling through the Siglec-sialoglycan axis appears to be enhanced through multiple mechanisms favoring tumor immune evasion similar to the PD-1/PD-L1 signaling pathway. Siglec expression on tumor-infiltrating immune cells appears increased in the immune suppressive microenvironment. At the same time, enhanced Siglec ligand expression has been reported for several tumor types as a result of aberrant glycosylation, glycan modifications, and the increased expression of sialoglycans on proteins and lipids. Siglec signaling has been identified as important regulator of anti-tumor immunity in the TME, but the key factors contributing to Siglec activation by tumor-associated sialoglycans are diverse and poorly defined. Among others, Siglec activation and signaling are co-determined by their expression levels, cell surface distribution, and their binding preferences for cis- and trans-ligands in the TME. Siglec binding preference are co-determined by the nature of the proteins/lipids to which the sialoglycans are attached and the multivalency of the interaction. Here, we review the current understanding and emerging conditions and factors involved in Siglec signaling in the TME and identify current knowledge gaps that exist in the field.
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Affiliation(s)
- Eline J. H. van Houtum
- Radiotherapy & OncoImmunology Laboratory, Department of Radiation Oncology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Christian Büll
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), Utrecht, Netherlands
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lenneke A. M. Cornelissen
- Radiotherapy & OncoImmunology Laboratory, Department of Radiation Oncology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Gosse J. Adema
- Radiotherapy & OncoImmunology Laboratory, Department of Radiation Oncology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
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12
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Dandopath Patra M. Comparative study of binding abilities of Siglec-7 to different ligands using molecular modeling techniques and structural analysis. J Carbohydr Chem 2021. [DOI: 10.1080/07328303.2021.1954656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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13
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Abstract
A dense and diverse array of glycans on glycoproteins and glycolipids decorate all cell surfaces. In vertebrates, many of these carry sialic acid, in a variety of linkages and glycan contexts, as their outermost sugar moiety. Among their functions, glycans engage complementary glycan binding proteins (lectins) to regulate cell physiology. Among the glycan binding proteins are the Siglecs, sialic acid binding immunoglobulin-like lectins. In humans, there are 14 Siglecs, most of which are expressed on overlapping subsets of immune system cells. Each Siglec engages distinct, endogenous sialylated glycans that initiate signaling programs and regulate cellular responses. Here, we explore the emerging science of Siglec ligands, including endogenous sialoglycoproteins and glycolipids and synthetic sialomimetics. Knowledge in this field promises to reveal new molecular pathways controlling cell physiology and new opportunities for therapeutic intervention.
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14
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Yoshimura A, Asahina Y, Chang LY, Angata T, Tanaka H, Kitajima K, Sato C. Identification and functional characterization of a Siglec-7 counter-receptor on K562 cells. J Biol Chem 2021; 296:100477. [PMID: 33640457 PMCID: PMC8040268 DOI: 10.1016/j.jbc.2021.100477] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 02/18/2021] [Accepted: 02/24/2021] [Indexed: 12/16/2022] Open
Abstract
Sialic acid (Sia)-binding immunoglobulin-like lectin 7 (Siglec-7) is an inhibitory receptor primarily expressed on natural killer (NK) cells and monocytes. Siglec-7 is known to negatively regulate the innate immune system through Sia binding to distinguish self and nonself; however, a counter-receptor bearing its natural ligand remains largely unclear. Here, we identified a counter-receptor of Siglec-7 using K562 hematopoietic carcinoma cells presenting cell surface ligands for Siglec-7. We affinity-purified the ligands using Fc-ligated recombinant Siglec-7 and diSia-dextran polymer, a strong inhibitor for Siglec-7. We then confirmed the counter-receptor for Siglec-7 as leukosialin (CD43) through mass spectrometry, immunoprecipitation, and proximity labeling. Additionally, we demonstrated that the cytotoxicity of NK cells toward K562 cells was suppressed by overexpression of leukosialin in a Siglec-7-dependent manner. Taken together, our data suggest that leukosialin on K562 is a counter-receptor for Siglec-7 on NK cells and that a cluster of the Sia-containing glycan epitope on leukosialin is key as trans-ligand for unmasking the cis-ligand.
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Affiliation(s)
- Atsushi Yoshimura
- Bioscience and Biotechnology Center, Nagoya University, Chikusa, Nagoya, Japan; Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan
| | - Yuki Asahina
- Bioscience and Biotechnology Center, Nagoya University, Chikusa, Nagoya, Japan; Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan
| | - Lan-Yi Chang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Takashi Angata
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Hiroshi Tanaka
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo, Japan
| | - Ken Kitajima
- Bioscience and Biotechnology Center, Nagoya University, Chikusa, Nagoya, Japan; Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan; Integrated Glyco-Biomedical Research Center (iGMed), Nagoya University, Chikusa, Nagoya, Japan; Institute for Glyco-Core Research (iGCORE), Nagoya University, Chikusa, Nagoya, Japan
| | - Chihiro Sato
- Bioscience and Biotechnology Center, Nagoya University, Chikusa, Nagoya, Japan; Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan; Integrated Glyco-Biomedical Research Center (iGMed), Nagoya University, Chikusa, Nagoya, Japan; Institute for Glyco-Core Research (iGCORE), Nagoya University, Chikusa, Nagoya, Japan.
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15
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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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16
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Läubli H, Varki A. Sialic acid-binding immunoglobulin-like lectins (Siglecs) detect self-associated molecular patterns to regulate immune responses. Cell Mol Life Sci 2020; 77:593-605. [PMID: 31485715 PMCID: PMC7942692 DOI: 10.1007/s00018-019-03288-x] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/11/2019] [Accepted: 08/28/2019] [Indexed: 12/12/2022]
Abstract
The mammalian immune system evolved to tightly regulate the elimination of pathogenic microbes and neoplastic transformed cells while tolerating our own healthy cells. Here, we summarize experimental evidence for the role of Siglecs-in particular CD33-related Siglecs-as self-receptors and their sialoglycan ligands in regulating this balance between recognition of self and non-self. Sialoglycans are found in the glycocalyx and extracellular fluids and matrices of all mammalian cells and can be considered as self-associated molecular patterns (SAMPs). We also provide an overview of the known interactions of Siglec receptors and sialoglycan-SAMPs. Manipulation of the Siglec-SAMP axis offers new therapeutic opportunities for the treatment of inflammatory conditions, autoimmune diseases and also cancer immunotherapy.
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Affiliation(s)
- Heinz Läubli
- Laboratory for Cancer Immunotherapy, University Hospital Basel, Petersgraben 4, 4031, Basel, Switzerland.
| | - Ajit Varki
- Department of Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, CA, 92093-0687, USA.
- Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, CA, 92093-0687, USA.
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17
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Abstract
Sialic acid-binding immunoglobulin-type lectins (Siglecs) are expressed on the majority of white blood cells of the immune system and play critical roles in immune cell signaling. Through recognition of sialic acid-containing glycans as ligands, they help the immune system distinguish between self and nonself. Because of their restricted cell type expression and roles as checkpoints in immune cell responses in human diseases such as cancer, asthma, allergy, neurodegeneration, and autoimmune diseases they have gained attention as targets for therapeutic interventions. In this review we describe the Siglec family, its roles in regulation of immune cell signaling, current efforts to define its roles in disease processes, and approaches to target Siglecs for treatment of human disease.
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Affiliation(s)
- Shiteng Duan
- Departments of Molecular Medicine, and Immunology and Microbiology, Scripps Research, La Jolla, California 92037, USA;
| | - James C Paulson
- Departments of Molecular Medicine, and Immunology and Microbiology, Scripps Research, La Jolla, California 92037, USA;
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18
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Movsisyan LD, Macauley MS. Structural advances of Siglecs: insight into synthetic glycan ligands for immunomodulation. Org Biomol Chem 2020; 18:5784-5797. [PMID: 32756649 DOI: 10.1039/d0ob01116a] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Sialic acid-binding immunoglobulin-like lectins (Siglecs) are transmembrane proteins of the immunoglobulin (Ig) superfamily predominantly expressed on the cells of our immune system. Siglecs recognize sialic acid via their terminal V-set domain. In mammals, sialic acid-terminated glycolipids and glycoproteins are the ligands of Siglecs, and the monomeric affinity of Siglecs for their sialic acid-containing ligands is weak. Significant efforts have been devoted toward the development of chemically modified sialoside ligands to target Siglecs with higher affinity and selectivity. In this review we discuss natural and synthetic sialoside ligands for each human Siglec, emphasizing the ligand binding determinants uncovered from recent advances in protein structural information. Potential therapeutic applications of these ligands are also discussed.
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Affiliation(s)
- Levon D Movsisyan
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Matthew S Macauley
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada and Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada.
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19
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The sugar code: letters and vocabulary, writers, editors and readers and biosignificance of functional glycan-lectin pairing. Biochem J 2019; 476:2623-2655. [PMID: 31551311 DOI: 10.1042/bcj20170853] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 08/31/2019] [Accepted: 09/04/2019] [Indexed: 12/11/2022]
Abstract
Ubiquitous occurrence in Nature, abundant presence at strategically important places such as the cell surface and dynamic shifts in their profile by diverse molecular switches qualifies the glycans to serve as versatile biochemical signals. However, their exceptional structural complexity often prevents one noting how simple the rules of objective-driven assembly of glycan-encoded messages are. This review is intended to provide a tutorial for a broad readership. The principles of why carbohydrates meet all demands to be the coding section of an information transfer system, and this at unsurpassed high density, are explained. Despite appearing to be a random assortment of sugars and their substitutions, seemingly subtle structural variations in glycan chains by a sophisticated enzymatic machinery have emerged to account for their specific biological meaning. Acting as 'readers' of glycan-encoded information, carbohydrate-specific receptors (lectins) are a means to turn the glycans' potential to serve as signals into a multitude of (patho)physiologically relevant responses. Once the far-reaching significance of this type of functional pairing has become clear, the various modes of spatial presentation of glycans and of carbohydrate recognition domains in lectins can be explored and rationalized. These discoveries are continuously revealing the intricacies of mutually adaptable routes to achieve essential selectivity and specificity. Equipped with these insights, readers will gain a fundamental understanding why carbohydrates form the third alphabet of life, joining the ranks of nucleotides and amino acids, and will also become aware of the importance of cellular communication via glycan-lectin recognition.
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20
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Miles LA, Hermans SJ, Crespi GAN, Gooi JH, Doughty L, Nero TL, Markulić J, Ebneth A, Wroblowski B, Oehlrich D, Trabanco AA, Rives ML, Royaux I, Hancock NC, Parker MW. Small Molecule Binding to Alzheimer Risk Factor CD33 Promotes Aβ Phagocytosis. iScience 2019; 19:110-118. [PMID: 31369984 PMCID: PMC6669322 DOI: 10.1016/j.isci.2019.07.023] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 01/16/2019] [Accepted: 07/15/2019] [Indexed: 02/06/2023] Open
Abstract
Polymorphism in the microglial receptor CD33 gene has been linked to late-onset Alzheimer disease (AD), and reduced expression of the CD33 sialic acid-binding domain confers protection. Thus, CD33 inhibition might be an effective therapy against disease progression. Progress toward discovery of selective CD33 inhibitors has been hampered by the absence of an atomic resolution structure. We report here the crystal structures of CD33 alone and bound to a subtype-selective sialic acid mimetic called P22 and use them to identify key binding residues by site-directed mutagenesis and binding assays to reveal the molecular basis for its selectivity toward sialylated glycoproteins and glycolipids. We show that P22, when presented on microparticles, increases uptake of the toxic AD peptide, amyloid-β (Aβ), into microglial cells. Thus, the sialic acid-binding site on CD33 is a promising pharmacophore for developing therapeutics that promote clearance of the Aβ peptide that is thought to cause AD.
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Affiliation(s)
- Luke A Miles
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3056, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia.
| | - Stefan J Hermans
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3056, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Gabriela A N Crespi
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3056, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Jonathan H Gooi
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3056, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Larissa Doughty
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3056, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Tracy L Nero
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3056, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Jasmina Markulić
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3056, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Andreas Ebneth
- Janssen Research & Development, a Division of Janssen Pharmaceutica N.V, 2340 Beerse, Belgium
| | - Berthold Wroblowski
- Janssen Research & Development, a Division of Janssen Pharmaceutica N.V, 2340 Beerse, Belgium
| | - Daniel Oehlrich
- Janssen Research & Development, a Division of Janssen Pharmaceutica N.V, 2340 Beerse, Belgium
| | - Andrés A Trabanco
- Neuroscience Medicinal Chemistry, Janssen Research & Development, 45007 Toledo, Spain
| | - Marie-Laure Rives
- Molecular and Cellular Pharmacology, Janssen Research & Development, LLC, La Jolla, CA 92121, USA
| | - Ines Royaux
- Janssen Research & Development, a Division of Janssen Pharmaceutica N.V, 2340 Beerse, Belgium
| | - Nancy C Hancock
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3056, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Michael W Parker
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3056, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia.
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21
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Hashimoto N, Ito S, Tsuchida A, Bhuiyan RH, Okajima T, Yamamoto A, Furukawa K, Ohmi Y, Furukawa K. The ceramide moiety of disialoganglioside (GD3) is essential for GD3 recognition by the sialic acid-binding lectin SIGLEC7 on the cell surface. J Biol Chem 2019; 294:10833-10845. [PMID: 31138648 DOI: 10.1074/jbc.ra118.007083] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 05/18/2019] [Indexed: 12/21/2022] Open
Abstract
To analyze the binding specificity of a sialic acid-recognizing lectin, sialic acid-binding Ig-like lectin 7 (SIGLEC7), to disialyl gangliosides (GD3s), here we established GD3-expressing cells by introducing GD3 synthase (GD3S or ST8SIA1) cDNA into a colon cancer cell line, DLD-1, that expresses no ligands for the recombinant protein SIGLEC7-Fc. SIGLEC7-Fc did not recognize newly-expressed GD3 on DLD-1 cells, even though GD3 was highly expressed, as detected by an anti-GD3 antibody. Because milk-derived GD3 could be recognized by this fusion protein when incorporated onto the surface of DLD-1 cells, we compared the ceramides in DLD-1-generated and milk-derived GD3s to identify the SIGLEC7-specific GD3 structures on the cell membrane, revealing that SIGLEC7 recognizes only GD3-containing regular ceramides but not phytoceramides. This was confirmed by knockdown/knockout of the sphingolipid delta(4)-desaturase/C4-monooxygenase (DES2) gene, involved in phytoceramide synthesis, disclosing that DES2 inhibition confers SIGLEC7 binding. Furthermore, knocking out fatty acid 2-hydroxylase also resulted in the emergence of SIGLEC7 binding to the cell surface. To analyze the effects of binding between SIGLEC7 and various GD3 species on natural killer function, we investigated cytotoxicity of peripheral blood mononuclear cells from healthy donors toward GD3S-transfected DLD-1 (DLD-1-GD3S) cells and DLD-1-GD3S cells with modified ceramides. We found that cytotoxicity is suppressed in DLD-1-GD3S cells with dehydroxylated GD3s. These results indicate that the ceramide structures in glycosphingolipids affect SIGLEC7 binding and distribution on the cell surface and influence cell sensitivity to killing by SIGLEC7-expressing effector cells.
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Affiliation(s)
- Noboru Hashimoto
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065, Japan,; Department of Tissue Regeneration, Tokushima University Graduate School of Biomedical Sciences, 3-18-5, Kuramoto-cho, Tokushima 770-8504, Japan
| | - Shizuka Ito
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065, Japan
| | - Akiko Tsuchida
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065, Japan
| | - Robiul H Bhuiyan
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065, Japan,; Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, 1200 Matsumoto, Kasugai, Aichi 487-8501, Japan, and
| | - Tetsuya Okajima
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065, Japan
| | - Akihito Yamamoto
- Department of Tissue Regeneration, Tokushima University Graduate School of Biomedical Sciences, 3-18-5, Kuramoto-cho, Tokushima 770-8504, Japan
| | - Keiko Furukawa
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, 1200 Matsumoto, Kasugai, Aichi 487-8501, Japan, and
| | - Yuhsuke Ohmi
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, 1200 Matsumoto, Kasugai, Aichi 487-8501, Japan, and
| | - Koichi Furukawa
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065, Japan,; Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, 1200 Matsumoto, Kasugai, Aichi 487-8501, Japan, and.
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22
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Sialic acid as a target for the development of novel antiangiogenic strategies. Future Med Chem 2018; 10:2835-2854. [PMID: 30539670 DOI: 10.4155/fmc-2018-0298] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Sialic acid is associated with glycoproteins and gangliosides of eukaryotic cells. It regulates various molecular interactions, being implicated in inflammation and cancer, where its expression is regulated by sialyltransferases and sialidases. Angiogenesis, the formation of new capillaries, takes place during inflammation and cancer, and represents the outcome of several interactions occurring at the endothelial surface among angiogenic growth factors, inhibitors, receptors, gangliosides and cell-adhesion molecules. Here, we elaborate on the evidences that many structures involved in angiogenesis are sialylated and that their interactions depend on sialic acid with implications in angiogenesis itself, inflammation and cancer. We also discuss the possibility to exploit sialic acid as a target for the development of novel antiangiogenic drugs.
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Rosenstock P, Horstkorte R, Gnanapragassam VS, Harth J, Kielstein H. Siglec-7 expression is reduced on a natural killer (NK) cell subset of obese humans. Immunol Res 2018; 65:1017-1024. [PMID: 28786023 PMCID: PMC5613057 DOI: 10.1007/s12026-017-8942-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Obesity leads to an altered adipocytokine production negatively effecting the function of natural killer cells (NK cells), which are important effector cells of the innate immune system. NK cells provide a defence against tumour cells or virus infected cells and have different activating and inhibitory surface receptors to distinguish between normal and transformed cells. One group of the inhibitory receptors are the sialic acid-binding immunoglobulin-like lectins (Siglecs). The aim of this study was to compare the expression of Siglecs-7, -9 and -10 on NK cells from normal weight and obese subjects. Therefore peripheral blood mononuclear cells (PBMC) were isolated from 10 normal weight (BMI < 25 kg/m2) and 11 obese (BMI > 30 kg/m2) blood donors and analysed by flow cytometry. Moreover, the amount of sialic acid on NK cell was determined using a fluorescent labelled lectin that binds terminal sialic acids. Percentages of immune cells were not altered between normal weight and obese individuals. CD56bright NK cells from obese subjects had a reduced expression of Siglec-7 while the expression of Siglec-9 was not altered. The reduction of Siglec-7 expression on CD56bright NK cells might be a marker for their dysfunction. Moreover, Siglecs-7, -9 and -10 are not expressed on the NK cell lines NK-92 and NKL. When comparing the two NK cell subpopulations CD56bright and CD56dim, CD56bright NK cells had a higher amount of sialic acids on their surface compared to CD56dim NK cells regardless of body weight.
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Affiliation(s)
- Philip Rosenstock
- Institute for Physiological Chemistry, Martin Luther University Halle-Wittenberg, Hollystraße 1, 06114, Halle (Saale), Germany. .,Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Grosse Steinstrasse 52 1, 06108, Halle (Saale), Germany.
| | - Rüdiger Horstkorte
- Institute for Physiological Chemistry, Martin Luther University Halle-Wittenberg, Hollystraße 1, 06114, Halle (Saale), Germany
| | | | - Jörg Harth
- Department of Transfusion Medicine, University Hospital Halle (Saale), Ernst-Grube-Straße 40, 06097, Halle (Saale), Germany
| | - Heike Kielstein
- Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Grosse Steinstrasse 52 1, 06108, Halle (Saale), Germany
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24
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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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25
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Abstract
Lectins recognize a diverse array of carbohydrate structures and perform numerous essential biological functions. Here we focus on only two families of lectins, the Siglecs and C-type lectins. Triggering of intracellular signaling cascades following ligand recognition by these receptors can have profound effects on the induction and modulation of immunity. In this chapter, we provide a brief overview of each family and then focus on selected examples that highlight how these lectins can influence myeloid cell functioning in health and disease. Receptors that are discussed include Sn (Siglec-1), CD33 (Siglec-3), and Siglec-5, -7, -8, -9, -10, -11, -14, -15, -E, -F, and -G as well as Dectin-1, MICL, Dectin-2, Mincle/MCL, and the macrophage mannose receptor.
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26
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Prescher H, Frank M, Gütgemann S, Kuhfeldt E, Schweizer A, Nitschke L, Watzl C, Brossmer R. Design, Synthesis, and Biological Evaluation of Small, High-Affinity Siglec-7 Ligands: Toward Novel Inhibitors of Cancer Immune Evasion. J Med Chem 2017; 60:941-956. [DOI: 10.1021/acs.jmedchem.6b01111] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
| | - Martin Frank
- Molecular
Structure Analysis Core Facility-W160, German Cancer Research Center, 69120 Heidelberg, Germany
| | | | | | - Astrid Schweizer
- Division
of Genetics, Department of Biology, University of Erlangen, 91058 Erlangen, Germany
| | - Lars Nitschke
- Division
of Genetics, Department of Biology, University of Erlangen, 91058 Erlangen, Germany
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27
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Loukachevitch LV, Bensing BA, Yu H, Zeng J, Chen X, Sullam PM, Iverson TM. Structures of the Streptococcus sanguinis SrpA Binding Region with Human Sialoglycans Suggest Features of the Physiological Ligand. Biochemistry 2016; 55:5927-5937. [PMID: 27685666 PMCID: PMC5388602 DOI: 10.1021/acs.biochem.6b00704] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Streptococcus sanguinis is a leading cause of bacterial infective endocarditis, a life-threatening infection of heart valves. S. sanguinis binds to human platelets with high avidity, and this adherence is likely to enhance virulence. Previous studies suggest that a serine-rich repeat adhesin termed SrpA mediates the binding of S. sanguinis to human platelets via its interaction with sialoglycans on the receptor GPIbα. However, in vitro binding assays with SrpA and defined sialoglycans failed to identify specific high-affinity ligands. To improve our understanding of the interaction between SrpA and human platelets, we determined cocrystal structures of the SrpA sialoglycan binding region (SrpABR) with five low-affinity ligands: three sialylated trisaccharides (sialyl-T antigen, 3'-sialyllactose, and 3'-sialyl-N-acetyllactosamine), a sialylated tetrasaccharide (sialyl-LewisX), and a sialyl galactose disaccharide component common to these sialoglyans. We then combined structural analysis with mutagenesis to further determine whether our observed interactions between SrpABR and glycans are important for binding to platelets and to better map the binding site for the physiological receptor. We found that the sialoglycan binding site of SrpABR is significantly larger than the sialoglycans cocrystallized in this study, which suggests that binding of SrpA to platelets either is multivalent or occurs via a larger, disialylated glycan.
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Affiliation(s)
| | - Barbara A. Bensing
- Division of Infectious Diseases, Veterans Affairs Medical Center, University of California at San Francisco and the Northern California Institute for Research and Education, San Francisco, California 94121, USA
| | - Hai Yu
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Jie Zeng
- Department of Chemistry, University of California, Davis, CA 95616, USA,School of Food Science, Henan Institute of Science and Technology, Xinxiang, 453003, China
| | - Xi Chen
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Paul M. Sullam
- Division of Infectious Diseases, Veterans Affairs Medical Center, University of California at San Francisco and the Northern California Institute for Research and Education, San Francisco, California 94121, USA
| | - T M Iverson
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, USA,Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37232, USA,Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, USA,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, USA,Corresponding Author To whom correspondence should be addressed:
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Structural basis for sulfation-dependent self-glycan recognition by the human immune-inhibitory receptor Siglec-8. Proc Natl Acad Sci U S A 2016; 113:E4170-9. [PMID: 27357658 DOI: 10.1073/pnas.1602214113] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Siglec-8 is a human immune-inhibitory receptor that, when engaged by specific self-glycans, triggers eosinophil apoptosis and inhibits mast cell degranulation, providing an endogenous mechanism to down-regulate immune responses of these central inflammatory effector cells. Here we used solution NMR spectroscopy to dissect the fine specificity of Siglec-8 toward different sialylated and sulfated carbohydrate ligands and determined the structure of the Siglec-8 lectin domain in complex with its prime glycan target 6'-sulfo sialyl Lewis(x) A canonical motif for sialic acid recognition, extended by a secondary motif formed by unique loop regions, recognizing 6-O-sulfated galactose dictates tight specificity distinct from other Siglec family members and any other endogenous glycan recognition receptors. Structure-guided mutagenesis revealed key contacts of both interfaces to be equally essential for binding. Our work provides critical structural and mechanistic insights into how Siglec-8 selectively recognizes its glycan target, rationalizes the functional impact of site-specific glycan sulfation in modulating this lectin-glycan interaction, and will enable the rational design of Siglec-8-targeted agonists to treat eosinophil- and mast cell-related allergic and inflammatory diseases, such as asthma.
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29
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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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30
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Schnaar RL. Glycobiology simplified: diverse roles of glycan recognition in inflammation. J Leukoc Biol 2016; 99:825-38. [PMID: 27004978 DOI: 10.1189/jlb.3ri0116-021r] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 02/18/2016] [Indexed: 12/30/2022] Open
Abstract
Glycans and complementary glycan-binding proteins are essential components in the language of cell-cell interactions in immunity. The study of glycan function is the purview of glycobiology, which has often been presented as an unusually complex discipline. In fact, the human glycome, composed of all of its glycans, is built primarily from only 9 building blocks that are combined by enzymes (writers) with specific and limited biosynthetic capabilities into a tractable and increasingly accessible number of potential glycan patterns that are functionally read by several dozen human glycan-binding proteins (readers). Nowhere is the importance of glycan recognition better understood than in infection and immunity, and knowledge in this area has already led to glycan mimetic anti-infective and anti-inflammatory drugs. This review includes a brief tutorial on human glycobiology and a limited number of specific examples of glycan-binding protein-glycan interactions that initiate and regulate inflammation. Examples include representatives from different glycan-binding protein families, including the C-type lectins (E-selectin, P-selectin, dectin-1, and dectin-2), sialic acid-binding immunoglobulin-like lectins (sialic acid-binding immunoglobulin-like lectins 8 and 9), galectins (galectin-1, galectin-3, and galectin-9), as well as hyaluronic acid-binding proteins. As glycoscience technologies advance, opportunities for enhanced understanding of glycans and their roles in leukocyte cell biology provide increasing opportunities for discovery and therapeutic intervention.
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Affiliation(s)
- Ronald L Schnaar
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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31
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Nagae M, Yamaguchi Y. Sugar recognition and protein-protein interaction of mammalian lectins conferring diverse functions. Curr Opin Struct Biol 2015; 34:108-15. [PMID: 26418728 DOI: 10.1016/j.sbi.2015.08.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 08/06/2015] [Accepted: 08/10/2015] [Indexed: 11/24/2022]
Abstract
Recent advances in structural analyses of mammalian lectins reveal atomic-level details of their fine specificities toward diverse endogenous and exogenous glycans. Local variations on a common scaffold can enable certain lectins to recognize complex carbohydrate ligands including branched glycans and O-glycosylated peptides. Simultaneous recognition of both glycan and the aglycon moieties enhances the affinity and specificity of lectins such as CLEC-2 and PILRα. Attention has been paid to the roles of galectin and RegIII family of proteins in protein-protein interactions involved in critical biological functions including signal transduction and bactericidal pore formation.
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Affiliation(s)
- Masamichi Nagae
- Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yoshiki Yamaguchi
- Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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32
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Horwacik I, Golik P, Grudnik P, Kolinski M, Zdzalik M, Rokita H, Dubin G. Structural Basis of GD2 Ganglioside and Mimetic Peptide Recognition by 14G2a Antibody. Mol Cell Proteomics 2015; 14:2577-90. [PMID: 26179345 DOI: 10.1074/mcp.m115.052720] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Indexed: 11/06/2022] Open
Abstract
Monoclonal antibodies targeting GD2 ganglioside (GD2) have recently been approved for the treatment of high risk neuroblastoma and are extensively evaluated in clinics in other indications. This study illustrates how a therapeutic antibody distinguishes between different types of gangliosides present on normal and cancer cells and informs how synthetic peptides can imitate ganglioside in its binding to the antibody. Using high resolution crystal structures we demonstrate that the ganglioside recognition by a model antibody (14G2a) is based primarily on an extended network of direct and water molecule mediated hydrogen bonds. Comparison of the GD2-Fab structure with that of a ligand free antibody reveals an induced fit mechanism of ligand binding. These conclusions are validated by directed mutagenesis and allowed structure guided generation of antibody variant with improved affinity toward GD2. Contrary to the carbohydrate, both evaluated mimetic peptides utilize a "key and lock" interaction mechanism complementing the surface of the antibody binding groove exactly as found in the empty structure. The interaction of both peptides with the Fab relies considerably on hydrophobic contacts however, the detailed connections differ significantly between the peptides. As such, the evaluated peptide carbohydrate mimicry is defined primarily in a functional and not in structural manner.
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Affiliation(s)
- Irena Horwacik
- From the ‡Laboratory of Molecular Genetics and Virology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 7 Gronostajowa St., 30-387 Krakow, Poland;
| | - Przemyslaw Golik
- §Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 7 Gronostajowa St., 30-387 Krakow, Poland
| | - Przemyslaw Grudnik
- §Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 7 Gronostajowa St., 30-387 Krakow, Poland
| | - Michal Kolinski
- ¶Bioinformatics Laboratory, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego St., 02-106 Warsaw, Poland
| | - Michal Zdzalik
- §Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 7 Gronostajowa St., 30-387 Krakow, Poland
| | - Hanna Rokita
- From the ‡Laboratory of Molecular Genetics and Virology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 7 Gronostajowa St., 30-387 Krakow, Poland
| | - Grzegorz Dubin
- §Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 7 Gronostajowa St., 30-387 Krakow, Poland; ‖Malopolska Centre of Biotechnology, Jagiellonian University, 7a Gronostajowa St., 30-387 Krakow, Poland
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33
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Suenaga T, Matsumoto M, Arisawa F, Kohyama M, Hirayasu K, Mori Y, Arase H. Sialic Acids on Varicella-Zoster Virus Glycoprotein B Are Required for Cell-Cell Fusion. J Biol Chem 2015; 290:19833-43. [PMID: 26105052 DOI: 10.1074/jbc.m114.635508] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Indexed: 12/28/2022] Open
Abstract
Varicella-zoster virus (VZV) is a member of the human Herpesvirus family that causes varicella (chicken pox) and zoster (shingles). VZV latently infects sensory ganglia and is also responsible for encephalomyelitis. Myelin-associated glycoprotein (MAG), a member of the sialic acid (SA)-binding immunoglobulin-like lectin family, is mainly expressed in neural tissues. VZV glycoprotein B (gB) associates with MAG and mediates membrane fusion during VZV entry into host cells. The SA requirements of MAG when associating with its ligands vary depending on the specific ligand, but it is unclear whether the SAs on gB are involved in the association with MAG. In this study, we found that SAs on gB are essential for the association with MAG as well as for membrane fusion during VZV infection. MAG with a point mutation in the SA-binding site did not bind to gB and did not mediate cell-cell fusion or VZV entry. Cell-cell fusion and VZV entry mediated by the gB-MAG interaction were blocked by sialidase treatment. N-glycosylation or O-glycosylation inhibitors also inhibited the fusion and entry mediated by gB-MAG interaction. Furthermore, gB with mutations in N-glycosylation sites, i.e. asparagine residues 557 and 686, did not associate with MAG, and the cell-cell fusion efficiency was low. Fusion between the viral envelope and cellular membrane is essential for host cell entry by herpesviruses. Therefore, these results suggest that SAs on gB play important roles in MAG-mediated VZV infection.
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Affiliation(s)
- Tadahiro Suenaga
- From the Department of Immunochemistry, Research Institute for Microbial Diseases and Laboratory of Immunochemistry, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan, and
| | - Maki Matsumoto
- From the Department of Immunochemistry, Research Institute for Microbial Diseases and Laboratory of Immunochemistry, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan, and
| | - Fuminori Arisawa
- From the Department of Immunochemistry, Research Institute for Microbial Diseases and
| | - Masako Kohyama
- From the Department of Immunochemistry, Research Institute for Microbial Diseases and Laboratory of Immunochemistry, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan, and
| | - Kouyuki Hirayasu
- From the Department of Immunochemistry, Research Institute for Microbial Diseases and Laboratory of Immunochemistry, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan, and
| | - Yasuko Mori
- the Division of Clinical Virology, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Hyogo, 650-0017, Japan
| | - Hisashi Arase
- From the Department of Immunochemistry, Research Institute for Microbial Diseases and Laboratory of Immunochemistry, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan, and
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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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35
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Izumi M, Otsuki A, Nishihara M, Okamoto R, Kajihara Y. Chemical synthesis of a synthetic analogue of the sialic acid-binding lectin siglec-7. Chembiochem 2014; 15:2503-7. [PMID: 25277834 DOI: 10.1002/cbic.201402494] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Indexed: 11/09/2022]
Abstract
As a basis for the development of an artificial carbohydrate-binding lectin, we chemically synthesized a domain of siglec-7, a well-characterized sialic-acid-binding lectin. The full polypeptide (127 amino acids) was constructed by sequential native chemical ligation (NCL) of five peptide segments. Because of poor cysteine availability for NCL, cysteine residues were introduced at suitable ligation sites; these cysteine residues were alkylated in order to mimic native glutamine or asparagine residues, or converted to an alanine residue by desulfurization after NCL. After folding the full-length polypeptide, the sialic-acid-binding activity of the synthetic siglec-7 was clearly demonstrated by STD NMR and ELISA experiments. We succeeded in the synthesis of siglec-7 by installing three extra cysteine residues with side-chain modifications and found that these modifications did not affect the binding activity.
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Affiliation(s)
- Masayuki Izumi
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan)
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36
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Macauley MS, Crocker PR, Paulson JC. Siglec-mediated regulation of immune cell function in disease. Nat Rev Immunol 2014; 14:653-66. [PMID: 25234143 DOI: 10.1038/nri3737] [Citation(s) in RCA: 723] [Impact Index Per Article: 72.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
All mammalian cells display a diverse array of glycan structures that differ from those that are found on microbial pathogens. Siglecs are a family of sialic acid-binding immunoglobulin-like receptors that participate in the discrimination between self and non-self, and that regulate the function of cells in the innate and adaptive immune systems through the recognition of their glycan ligands. In this Review, we describe the recent advances in our understanding of the roles of Siglecs in the regulation of immune cell function in infectious diseases, inflammation, neurodegeneration, autoimmune diseases and cancer.
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Affiliation(s)
- Matthew S Macauley
- Departments of Cell and Molecular Biology, Immunology and Microbial Science, and Physiological Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Paul R Crocker
- Division of Cell Signalling and Immunology, Wellcome Trust Building, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - James C Paulson
- Departments of Cell and Molecular Biology, Immunology and Microbial Science, and Physiological Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA
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PILRα and PILRβ have a siglec fold and provide the basis of binding to sialic acid. Proc Natl Acad Sci U S A 2014; 111:8221-6. [PMID: 24843130 DOI: 10.1073/pnas.1320716111] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Paired immunoglobulin-like type 2 receptor α (PILRα) and β (PILRβ) belong to the PILR family and are related to innate immune regulation in various species. Despite their high sequence identity, PILRα and PILRβ are shown to have variant sialic acid (SA) binding avidities. To explore the molecular basis of this interaction, we solved the crystal structures of PILRα and PILRβ at resolutions of 1.6 Å and 2.2 Å, respectively. Both molecules adopt a typical siglec fold but use a hydrophobic bond to substitute the siglec-specific disulfide linkage for protein stabilization. We further used HSV-1 glycoprotein B (gB) as a representative molecule to study the PILR-SA interaction. Deploying site-directed mutagenesis, we demonstrated that three residues (Y2, R95, and W108) presented on the surface of PILRα form the SA binding site equivalent to those in siglecs but are arranged in a unique linear mode. PILRβ differs from PILRα in one of these three residues (L108), explaining its inability to engage gB. Mutation of L108 to tryptophan in PILRβ restored the gB-binding capacity. We further solved the structure of this PILRβ mutant complexed with SA, which reveals the atomic details mediating PILR/SA recognition. In comparison with the free PILR structures, amino acid Y2 oriented variantly in the complex structure, thereby disrupting the linear arrangement of PILR residues Y2, R95, and W108. In conclusion, our study provides significant implications for the PILR-SA interaction and paves the way for understanding PILR-related ligand binding.
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Li CW, Hon KW, Ghosh B, Li PH, Lin HY, Chan PH, Lin CH, Chen YC, Mong KKT. Synthesis of Oligomeric Mannosides and Their Structure-Binding Relationship with Concanavalin A. Chem Asian J 2014; 9:1786-96. [DOI: 10.1002/asia.201402029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Revised: 03/20/2014] [Indexed: 01/15/2023]
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Suzuki T, Makyio H, Ando H, Komura N, Menjo M, Yamada Y, Imamura A, Ishida H, Wakatsuki S, Kato R, Kiso M. Expanded potential of seleno-carbohydrates as a molecular tool for X-ray structural determination of a carbohydrate-protein complex with single/multi-wavelength anomalous dispersion phasing. Bioorg Med Chem 2014; 22:2090-101. [PMID: 24631362 DOI: 10.1016/j.bmc.2014.02.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 02/18/2014] [Indexed: 01/10/2023]
Abstract
Seleno-lactoses have been successfully synthesized as candidates for mimicking carbohydrate ligands for human galectin-9 N-terminal carbohydrate recognition domain (NCRD). Selenium was introduced into the mono- or di-saccharides using p-methylselenobenzoic anhydride (Tol2Se) as a novel selenating reagent. The TolSe-substituted monosaccharides were converted into selenoglycosyl donors or acceptors, which were reacted with coupling partners to afford seleno-lactoses. The seleno-lactoses were converted to the target compounds. The structure of human galectin-9 NCRD co-crystallized with 6-MeSe-lactose was determined with single/multi-wavelength anomalous dispersion (SAD/MAD) phasing and was similar to that of the co-crystal with natural lactose.
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Affiliation(s)
- Tatsuya Suzuki
- Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida Ushinomiya-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hisayoshi Makyio
- Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Hiromune Ando
- Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida Ushinomiya-cho, Sakyo-ku, Kyoto 606-8501, Japan.
| | - Naoko Komura
- Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida Ushinomiya-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Masanori Menjo
- Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan
| | - Yusuke Yamada
- Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Akihiro Imamura
- Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan
| | - Hideharu Ishida
- Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan
| | - Soichi Wakatsuki
- Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan; Photon Science, SLAC Natl. Accelerator Laboratory Structure Science, 2575 Sand Hill Road, MS 69, Menlo Park, CA 94025-7015, USA; Department of Structural Biology, Stanford University, Beckman Center B105, 279 Campus Drive, Stanford, CA 94305-5126, USA
| | - Ryuichi Kato
- Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Makoto Kiso
- Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida Ushinomiya-cho, Sakyo-ku, Kyoto 606-8501, Japan
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Glycocalyx engineering reveals a Siglec-based mechanism for NK cell immunoevasion. Nat Chem Biol 2013; 10:69-75. [PMID: 24292068 PMCID: PMC3893890 DOI: 10.1038/nchembio.1388] [Citation(s) in RCA: 325] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 10/01/2013] [Indexed: 12/21/2022]
Abstract
The increase of cell surface sialic acid is a characteristic shared by many tumor types. A correlation between hypersialylation and immunoprotection has been observed, but few hypotheses have provided a mechanistic understanding of this immunosuppressive phenomenon. Here, we show that increasing sialylated glycans on cancer cells inhibits human natural killer (NK) cell activation through the recruitment of sialic acid-binding immunoglobulin-like lectin 7 (Siglec-7). Key to these findings was the use of glycopolymers end-functionalized with phospholipids, which enable the introduction of synthetically defined glycans onto cancer cell surfaces. Remodeling the sialylation status of cancer cells affected the susceptibility to NK cell cytotoxicity via Siglec-7 engagement in a variety of tumor types. These results support a model in which hypersialylation offers a selective advantage to tumor cells under pressure from NK immunosurveillance by increasing Siglec ligands. We also exploited this finding to protect allogeneic and xenogeneic primary cells from NK-mediated killing, suggesting the potential of Siglecs as therapeutic targets in cell transplant therapy.
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UENO-NOTO KAORI, ISE SEIKO, TAKANO KEIKO. CHEMICAL DESCRIPTION OF THE INTERACTION BETWEEN GLYCAN LIGAND AND SIGLEC-7 USING AB INITIO FMO METHOD AND CLASSICAL MD SIMULATION. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2013. [DOI: 10.1142/s0219633613500600] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We clarified in detail the theoretical features of the interaction between the glycan ligand containing α(2,8)-disialyl residue and a lectin called Siglec (sialic acid Ig-like binding lectin)-7 by ab initio fragment molecular orbital (FMO) calculations and classical molecular dynamics (MD) simulations. By comparing the ligand–Siglec-7 interaction of the wild-type Siglec-7 and those of mutant-Siglec-7s, we herein describe protein–glycan interactions thoroughly, and provide fundamentals to elucidate ligand-recognition mechanism. The experimentally observed decrease in ligand binding produced by mutagenesis at residues in non-active site was explained with MD simulations; both Trp85 and Trp74 residues are fundamental in structural stability of the Siglec-7, which is involved in the binding of the glycan ligand. The interaction energies obtained by the FMO method were consistent with the experimental ligand-binding results. The glycan ligand preferentially interacted with Siglec-7 via sialic acid residues. The stabilization by the dispersion interaction between the neutral parts of the ligand was also considerable in the binding.
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Affiliation(s)
- KAORI UENO-NOTO
- Center for Natural Sciences, College of Liberal Arts and Sciences, Kitasato University 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan
| | - SEIKO ISE
- Department of Chemistry and Biochemistry, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - KEIKO TAKANO
- Department of Chemistry and Biochemistry, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
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Rillahan CD, Schwartz E, Rademacher C, McBride R, Rangarajan J, Fokin VV, Paulson JC. On-chip synthesis and screening of a sialoside library yields a high affinity ligand for Siglec-7. ACS Chem Biol 2013; 8:1417-22. [PMID: 23597400 DOI: 10.1021/cb400125w] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The Siglec family of sialic acid-binding proteins are differentially expressed on white blood cells of the immune system and represent an attractive class of targets for cell-directed therapy. Nanoparticles decorated with high-affinity Siglec ligands show promise for delivering cargo to Siglec-bearing cells, but this approach has been limited by a lack of ligands with suitable affinity and selectivity. Building on previous work employing solution-phase sialoside library synthesis and subsequent microarray screening, we herein report a more streamlined 'on-chip' synthetic approach. By printing a small library of alkyne sialosides and subjecting these to 'on-chip' click reactions, the largest sialoside analogue library to date was generated. Siglec-screening identified a selective Siglec-7 ligand, which when displayed on liposomal nanoparticles, allows for targeting of Siglec-7(+) cells in peripheral human blood. In silico docking to the crystal structure of Siglec-7 provides a rationale for the affinity gains observed for this novel sialic acid analogue.
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Affiliation(s)
| | | | - Christoph Rademacher
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am
Mühlenberg 1, 14424 Potsdam, Germany
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Nahalka J. Glycocodon theory--the first table of glycocodons. J Theor Biol 2012; 307:193-204. [PMID: 22609469 DOI: 10.1016/j.jtbi.2012.05.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 04/11/2012] [Accepted: 05/09/2012] [Indexed: 01/24/2023]
Abstract
Hydrophobic cellular membranes separate cells from an environment that is generally based on water. Therefore, it is not surprising that hydrophilic glycans and glycoproteins are exposed on the lipidic surface of membranes and that the glycocalyx has evolved in all basic cell types. During the evolution of multicellular life, the surface exposed protein-glycan interactions were taken as the origin of the language of cell-cell communication. The bioinformatics analysis presented here reveals that the amino acid triplets, the glycocodons, can be deduced for each glycan letter (monosaccharide). This theory proposes to distinguish between the "sugar code" (the sugar sequence) and the "glycocode" (evolutionary selected amino acids recognising the mono-sugar). Similarly to genetic code, original glycocodons are related to G, A, V, and D amino acids. Modern glycocodons can be deduced from GAVD-glycocodons using hydropathic similarity. In general, the amino acid triplets can be assembled from one dipeptide that is specific to a monosaccharide plus a polar amino acid. This theory may shed a different light on the reason for WWD conservation in the active sites of oligosaccharyltransferases and for GGQ in the active sites of ribosomes.
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Affiliation(s)
- Jozef Nahalka
- Institute of Chemistry, Centre for Glycomics, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84538 Bratislava, Slovak Republic.
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Rademacher C, Bru T, McBride R, Robison E, Nycholat CM, Kremer EJ, Paulson JC. A Siglec-like sialic-acid-binding motif revealed in an adenovirus capsid protein. Glycobiology 2012; 22:1086-91. [PMID: 22522600 DOI: 10.1093/glycob/cws073] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Sialic-acid-binding immunoglobulin-like lectins (Siglecs) are a family of transmembrane receptors that are well documented to play roles in regulation of innate and adaptive immune responses. To see whether the features that define the molecular recognition of sialic acid were found in other sialic-acid-binding proteins, we analyzed 127 structures with bound sialic acids found in the Protein Data Bank database. Of these, the canine adenovirus 2-fiber knob protein showed close local structural relationship to Siglecs despite low sequence similarity. The fiber knob harbors a noncanonical sialic-acid recognition site, which was then explored for detailed specificity using a custom glycan microarray comprising 58 diverse sialosides. It was found that the adenoviral protein preferentially recognizes the epitope Neu5Acα2-3[6S]Galβ1-4GlcNAc, a structure previously identified as the preferred ligand for Siglec-8 in humans and Siglec-F in mice. Comparison of the Siglec and fiber knob sialic-acid-binding sites reveal conserved structural elements that are not clearly identifiable from the primary amino acid sequence, suggesting a Siglec-like sialic-acid-binding motif that comprises the consensus features of these proteins in complex with sialic acid.
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Affiliation(s)
- Christoph Rademacher
- Departments of Chemical Physiology and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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Crocker PR, McMillan SJ, Richards HE. CD33-related siglecs as potential modulators of inflammatory responses. Ann N Y Acad Sci 2012; 1253:102-11. [DOI: 10.1111/j.1749-6632.2011.06449.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Abstract
Sialic acid-binding Ig-like lectins, or Siglecs, vary in their specificity for sialic acid-containing ligands and are mainly expressed by cells of the immune system. Many Siglecs are inhibitory receptors expressed in innate immune cells that regulate inflammation mediated by damage-associated and pathogen-associated molecular patterns (DAMPs and PAMPs). This family also includes molecules involved in adhesion and phagocytosis and receptors that can associate with the ITAM-containing DAP12 adaptor. Siglecs contribute to the inhibition of immune cells both by binding to cis ligands (expressed in the same cells) and by responding to pathogen-derived sialoglycoconjugates. They can help maintain tolerance in B lymphocytes, modulate the activation of conventional and plasmacytoid dendritic cells, and contribute to the regulation of T cell function both directly and indirectly. Siglecs modulate immune responses, influencing almost every cell in the immune system, and are of relevance both in health and disease.
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Affiliation(s)
- Shiv Pillai
- Center for Cancer Research, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129, USA.
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Janas T, Janas T. Membrane oligo- and polysialic acids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2923-32. [DOI: 10.1016/j.bbamem.2011.08.036] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 08/29/2011] [Accepted: 08/31/2011] [Indexed: 10/17/2022]
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Redelinghuys P, Antonopoulos A, Liu Y, Campanero-Rhodes MA, McKenzie E, Haslam SM, Dell A, Feizi T, Crocker PR. Early murine T-lymphocyte activation is accompanied by a switch from N-Glycolyl- to N-acetyl-neuraminic acid and generation of ligands for siglec-E. J Biol Chem 2011; 286:34522-32. [PMID: 21835922 PMCID: PMC3186437 DOI: 10.1074/jbc.m111.243410] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
It is well established that murine T-lymphocyte activation is accompanied by major changes in cell-surface sialylation, potentially influencing interactions with sialic acid-binding immunoglobulin-like lectins (siglecs). In the present study, we analyzed early activation of murine CD4+ and CD8+ T-lymphocytes at 24 h. We observed a striking and selective up-regulation in the binding of a recombinant soluble form of siglec-E, an inhibitory siglec, which is expressed on several myeloid cell types including antigen-presenting dendritic cells. In contrast, much lower levels of T cell binding were observed with other siglecs, including sialoadhesin, CD22, and siglec-F and the plant lectins Maackia amurensis leukoagglutinin and Sambucus nigra agglutinin. By mass spectrometry, the sialic acid content of 24-h-activated CD4+ and CD8+ T-lymphocytes exhibited an increased proportion of N-acetyl-neuraminic acid (NeuAc) to N-glycolyl-neuraminic acid (NeuGc) in N-glycans. Reduced levels of NeuGc on the surface of activated T cells were demonstrated using an antibody specific for NeuGc and the expression levels of the gene encoding NeuAc- to NeuGc-converting enzyme, CMP-NeuAc hydroxylase, were also reduced. Siglec-E bound a wide range of sialylated structures in glycan arrays, had a preference for NeuAc versus NeuGc-terminated sequences and could recognize a set of sialoglycoproteins that included CD45, in lysates from activated T-lymphocytes. Collectively, these results show that early in T cell activation, glycan remodelling involves a switch from NeuGc- to NeuAc-terminating oligosaccharides on cell surface glycoproteins. This is associated with a strong up-regulation of siglec-E ligands, which may be important in promoting cellular interactions between early activated T-lymphocytes and myeloid cells expressing this inhibitory receptor.
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Affiliation(s)
- Pierre Redelinghuys
- Division of Cell Signalling and Immunology, Wellcome Trust Biocentre, University of Dundee, Dundee DD1 5EH, United Kingdom
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Pyburn TM, Bensing BA, Xiong YQ, Melancon BJ, Tomasiak TM, Ward NJ, Yankovskaya V, Oliver KM, Cecchini G, Sulikowski GA, Tyska MJ, Sullam PM, Iverson TM. A structural model for binding of the serine-rich repeat adhesin GspB to host carbohydrate receptors. PLoS Pathog 2011; 7:e1002112. [PMID: 21765814 PMCID: PMC3131266 DOI: 10.1371/journal.ppat.1002112] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 04/25/2011] [Indexed: 11/18/2022] Open
Abstract
GspB is a serine-rich repeat (SRR) adhesin of Streptococcus gordonii that mediates binding of this organism to human platelets via its interaction with sialyl-T antigen on the receptor GPIbα. This interaction appears to be a major virulence determinant in the pathogenesis of infective endocarditis. To address the mechanism by which GspB recognizes its carbohydrate ligand, we determined the high-resolution x-ray crystal structure of the GspB binding region (GspB(BR)), both alone and in complex with a disaccharide precursor to sialyl-T antigen. Analysis of the GspB(BR) structure revealed that it is comprised of three independently folded subdomains or modules: 1) an Ig-fold resembling a CnaA domain from prokaryotic pathogens; 2) a second Ig-fold resembling the binding region of mammalian Siglecs; 3) a subdomain of unique fold. The disaccharide was found to bind in a pocket within the Siglec subdomain, but at a site distinct from that observed in mammalian Siglecs. Confirming the biological relevance of this binding pocket, we produced three isogenic variants of S. gordonii, each containing a single point mutation of a residue lining this binding pocket. These variants have reduced binding to carbohydrates of GPIbα. Further examination of purified GspB(BR)-R484E showed reduced binding to sialyl-T antigen while S. gordonii harboring this mutation did not efficiently bind platelets and showed a significant reduction in virulence, as measured by an animal model of endocarditis. Analysis of other SRR proteins revealed that the predicted binding regions of these adhesins also had a modular organization, with those known to bind carbohydrate receptors having modules homologous to the Siglec and Unique subdomains of GspB(BR). This suggests that the binding specificity of the SRR family of adhesins is determined by the type and organization of discrete modules within the binding domains, which may affect the tropism of organisms for different tissues.
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Affiliation(s)
- Tasia M. Pyburn
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute of Chemical Biology, Nashville, Tennessee, United States of America
| | - Barbara A. Bensing
- Department of Medicine, Veterans Affairs Medical Center and the University of California, San Francisco, California, United States of America
| | - Yan Q. Xiong
- Department of Medicine, Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Bruce J. Melancon
- Vanderbilt Institute of Chemical Biology, Nashville, Tennessee, United States of America
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Thomas M. Tomasiak
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute of Chemical Biology, Nashville, Tennessee, United States of America
| | - Nicholas J. Ward
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Victoria Yankovskaya
- Molecular Biology Division, Veterans Affairs Medical Center, San Francisco, California, United States of America
| | - Kevin M. Oliver
- Vanderbilt Institute of Chemical Biology, Nashville, Tennessee, United States of America
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Gary Cecchini
- Molecular Biology Division, Veterans Affairs Medical Center, San Francisco, California, United States of America
- Department of Biochemistry & Biophysics University of California, San Francisco, California, United States of America
| | - Gary A. Sulikowski
- Vanderbilt Institute of Chemical Biology, Nashville, Tennessee, United States of America
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Matthew J. Tyska
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Paul M. Sullam
- Department of Medicine, Veterans Affairs Medical Center and the University of California, San Francisco, California, United States of America
| | - T. M. Iverson
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute of Chemical Biology, Nashville, Tennessee, United States of America
- Department of Biochemistry, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- * E-mail:
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50
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Kawasaki Y, Ito A, Withers DA, Taima T, Kakoi N, Saito S, Arai Y. Ganglioside DSGb5, preferred ligand for Siglec-7, inhibits NK cell cytotoxicity against renal cell carcinoma cells. Glycobiology 2010; 20:1373-9. [PMID: 20663960 DOI: 10.1093/glycob/cwq116] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In renal cell carcinoma (RCC), the presence of higher gangliosides correlates with systematic metastasis. Disialosyl globopentaosylceramide (DSGb5) was identified previously as one of the major gangliosides from RCC tissues. Siglec-7 (sialic acid-binding Ig-like lectin-7), expressed on natural killer (NK) cells as an inhibitory receptor, has a striking preference for internally branched α2,6-linked disialic gangliosides such as DSGb5. To clarify the functional role of DSGb5 in RCC metastases, we have investigated whether DSGb5 expressed on RCC cells can modulate NK cell cytotoxicity in a Siglec-7-dependent manner. The binding activity of RCC cells to Siglec-7-Fc fusion protein was specifically inhibited by anti-DSGb5 monoclonal antibody and transfection of siRNA for ST6GalNAcVI (synthetase of DSGb5). These observations showed that Siglec-7-Fc fusion protein specifically bound to DSGb5 expressed on RCC cells. In contrast, the sialic acid-binding site of Siglec-7 on NK cells was masked by cis interactions with endogenous sialoconjugates at the cell surface, but it could be unmasked by sialidase treatment of the NK cells. Following sialidase treatment of NK cells, NK cell cytotoxicity against RCC cells with high DSGb5 expression was significantly decreased relative to cells with low DSGb5 expression. These findings indicate that such NK cell cytotoxicity against RCC cells could be inhibited by the interaction between Siglec-7 on effecter cells and DSGb5 on target cells. The results of the present study suggest that DSGb5 expressed on RCC cells can downregulate NK cell cytotoxicity in a DSGb5-Siglec-7-dependent manner and that RCC cells with DSGb5 create favorable circumstance for their own survival and metastases.
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Affiliation(s)
- Yoshihide Kawasaki
- Department of Urology, Tohoku University School of Medicine, Sendai 980-8574, Japan
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