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Zheng X, Li Y, Cui T, Yang J, Meng X, Wang H, Chen L, He J, Chen N, Meng L, Ding L, Xie R. Traceless Protein-Selective Glycan Labeling and Chemical Modification. J Am Chem Soc 2023; 145:23670-23680. [PMID: 37857274 DOI: 10.1021/jacs.3c07889] [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: 10/21/2023]
Abstract
Executing glycan editing at a molecular level not only is pivotal for the elucidation of complicated mechanisms involved in glycan-relevant biological processes but also provides a promising solution to potentiate disease therapy. However, the precision control of glycan modification or glyco-editing on a selected glycoprotein is by far a grand challenge. Of note is to preserve the intact cellular glycan landscape, which is preserved after editing events are completed. We report herein a versatile, traceless glycan modification methodology for customizing the glycoforms of targeted proteins (subtypes), by orchestrating chemical- and photoregulation in a protein-selective glycoenzymatic system. This method relies on a three-module, ligand-photocleavable linker-glycoenzyme (L-P-G) conjugate. We demonstrated that RGD- or synthetic carbohydrate ligand-containing conjugates (RPG and SPG) would not activate until after the ligand-receptor interaction is accomplished (chemical regulation). RPG and SPG can both release the glycoenzyme upon photoillumination (photoregulation). The adjustable glycoenzyme activity, combined with ligand recognition selectivity, minimizes unnecessary glycan editing perturbation, and photolytic cleavage enables precise temporal control of editing events. An altered target protein turnover and dimerization were observed in our system, emphasizing the significance of preserving the native physiological niche of a particular protein when precise modification on the carbohydrate epitope occurs.
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Affiliation(s)
- Xiaocui Zheng
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Yiran Li
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Tongxiao Cui
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Jing Yang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Xiangfeng Meng
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Haiqi Wang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Liusheng Chen
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Jian He
- Department of Nuclear Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China
| | - Nan Chen
- ChinaChomiX Biotech (Nanjing) Co., Ltd., Nanjing 210061, China
| | - Liying Meng
- Department of Medical Experimental Center, Qilu Hospital (Qingdao), Cheeloo College of Medicine, Shandong University, Qingdao 266035, China
| | - Lin Ding
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, China
| | - Ran Xie
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, China
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2
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Prescher H, Schweizer A, Frank M, Kuhfeldt E, Ring J, Nitschke L. Targeting Human CD22/Siglec-2 with Dimeric Sialosides as Novel Oligosaccharide Mimetics. J Med Chem 2022; 65:10588-10610. [PMID: 35881556 DOI: 10.1021/acs.jmedchem.2c00765] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Significant interest in the development of high-affinity ligands for Siglecs exists due to the various therapeutically relevant functions of these proteins. Here, we report a new strategy to develop and design Siglec ligands as disialyl-oligosaccharide mimetics exemplified on Siglec-2 (CD22). We report insights into development of dimeric ligands with high affinity and avidity to cell surface-expressed CD22, assay development, tool compounds, structure activity relationships, and biological data on calcium flux regulation in B-cells. The binding modes of selected ligands have been modeled based on state-of-the-art molecular dynamics simulations on the microsecond timescale, providing detailed views on ligand binding and opening a new perspective on drug design efforts for Siglecs. High-avidity dimeric ligands containing a linker opening the way towards bispecifics are presented as well.
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Affiliation(s)
| | - Astrid Schweizer
- Chair of Genetics, Department of Biology, University of Erlangen, 91058 Erlangen, Germany
| | - Martin Frank
- Biognos AB, Generatorsgatan 1, 40274 Göteborg, Sweden
| | | | - Julia Ring
- Chair of Genetics, Department of Biology, University of Erlangen, 91058 Erlangen, Germany
| | - Lars Nitschke
- Chair of Genetics, Department of Biology, University of Erlangen, 91058 Erlangen, Germany
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3
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Rashidieh B, Ansari AM, Behdani M, Darvishi B, Habibi-Anbouhi M. Extremely low frequency magnetic field enhances expression of a specific recombinant protein in bacterial host. Anal Biochem 2022; 652:114745. [DOI: 10.1016/j.ab.2022.114745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 05/10/2022] [Accepted: 05/18/2022] [Indexed: 11/29/2022]
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4
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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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5
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Lim J, Sari-Ak D, Bagga T. Siglecs as Therapeutic Targets in Cancer. BIOLOGY 2021; 10:1178. [PMID: 34827170 PMCID: PMC8615218 DOI: 10.3390/biology10111178] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/03/2021] [Accepted: 11/08/2021] [Indexed: 02/06/2023]
Abstract
Hypersialylation is a common post-translational modification of protein and lipids found on cancer cell surfaces, which participate in cell-cell interactions and in the regulation of immune responses. Sialic acids are a family of nine-carbon α-keto acids found at the outermost ends of glycans attached to cell surfaces. Given their locations on cell surfaces, tumor cells aberrantly overexpress sialic acids, which are recognized by Siglec receptors found on immune cells to mediate broad immunomodulatory signaling. Enhanced sialylation exposed on cancer cell surfaces is exemplified as "self-associated molecular pattern" (SAMP), which tricks Siglec receptors found on leukocytes to greatly down-regulate immune responsiveness, leading to tumor growth. In this review, we focused on all 15 human Siglecs (including Siglec XII), many of which still remain understudied. We also highlighted strategies that disrupt the course of Siglec-sialic acid interactions, such as antibody-based therapies and sialic acid mimetics leading to tumor cell depletion. Herein, we introduced the central roles of Siglecs in mediating pro-tumor immunity and discussed strategies that target these receptors, which could benefit improved cancer immunotherapy.
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Affiliation(s)
- Jackwee Lim
- Singapore Immunology Network, A*STAR, 8a Biomedical Grove, Singapore 138648, Singapore;
| | - Duygu Sari-Ak
- Department of Medical Biology, School of Medicine, University of Health Sciences, Istanbul 34668, Turkey;
| | - Tanaya Bagga
- Singapore Immunology Network, A*STAR, 8a Biomedical Grove, Singapore 138648, Singapore;
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6
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Current Status on Therapeutic Molecules Targeting Siglec Receptors. Cells 2020; 9:cells9122691. [PMID: 33333862 PMCID: PMC7765293 DOI: 10.3390/cells9122691] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/09/2020] [Accepted: 12/12/2020] [Indexed: 12/15/2022] Open
Abstract
The sialic acid-binding immunoglobulin-type of lectins (Siglecs) are receptors that recognize sialic acid-containing glycans. In the majority of the cases, Siglecs are expressed on immune cells and play a critical role in regulating immune cell signaling. Over the years, it has been shown that the sialic acid-Siglec axis participates in immunological homeostasis, and that any imbalance can trigger different pathologies, such as autoimmune diseases or cancer. For all this, different therapeutics have been developed that bind to Siglecs, either based on antibodies or being smaller molecules. In this review, we briefly introduce the Siglec family and we compile a description of glycan-based molecules and antibody-based therapies (including CAR-T and bispecific antibodies) that have been designed to therapeutically targeting Siglecs.
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7
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Both P, Riese M, Gray CJ, Huang K, Pallister EG, Kosov I, Conway LP, Voglmeir J, Flitsch SL. Applications of a highly α2,6-selective pseudosialidase. Glycobiology 2018; 28:261-268. [PMID: 29506202 DOI: 10.1093/glycob/cwy016] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 02/27/2018] [Indexed: 12/15/2022] Open
Abstract
Within human biology, combinations of regioisomeric motifs of α2,6- or α2,3-sialic acids linked to galactose are frequently observed attached to glycoconjugates. These include glycoproteins and glycolipids, with each linkage carrying distinct biological information and function. Microbial linkage-specific sialidases have become important tools for studying the role of these sialosides in complex biological settings, as well as being used as biocatalysts for glycoengineering. However, currently, there is no α2,6-specific sialidase available. This gap has been addressed herein by exploiting the ability of a Photobacterium sp. α2,6-sialyltransferase to catalyze trans-sialidation reversibly and in a highly linkage-specific manner, acting as a pseudosialidase in the presence of cytidine monophosphate. Selective, near quantitative removal of α2,6-linked sialic acids was achieved from a wide range of sialosides including small molecules conjugates, simple glycan, glycopeptide and finally complex glycoprotein including both linkages.
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Affiliation(s)
- Peter Both
- School of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, UK
| | - Michel Riese
- School of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, UK
| | - Christopher J Gray
- School of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, UK
| | - Kun Huang
- School of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, UK
| | - Edward G Pallister
- School of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, UK
| | - Iaroslav Kosov
- School of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, UK
| | - Louis P Conway
- Glycomics Glycan Bioengineering Research Center, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Josef Voglmeir
- Glycomics Glycan Bioengineering Research Center, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Sabine L Flitsch
- School of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, UK
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8
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Sialic Acid Mimetics to Target the Sialic Acid-Siglec Axis. Trends Biochem Sci 2016; 41:519-531. [PMID: 27085506 DOI: 10.1016/j.tibs.2016.03.007] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 03/16/2016] [Accepted: 03/28/2016] [Indexed: 01/31/2023]
Abstract
Sialic acid sugars are vital regulators of the immune system through binding to immunosuppressive sialic acid-binding immunoglobulin-like lectin (Siglec) receptors on immune cells. Aberrant sialic acid-Siglec interactions are associated with an increasing number of pathologies including infection, autoimmunity, and cancer. Therefore, the sialic acid-Siglec axis is an emerging target to prevent or affect the course of several diseases. Chemical modifications of the natural sialic acid ligands have led to sialic acid mimetics (SAMs) with improved binding affinity and selectivity towards Siglecs. Recent progress in glycobiotechnology allows the presentation of these SAMs on nanoparticles, polymers, and living cells via bioorthogonal synthesis. These developments now enable the detailed study of the sialic acid-Siglec axis including its therapeutic potential as an immune modulator.
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9
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Mesch S, Lemme K, Wittwer M, Koliwer-Brandl H, Schwardt O, Kelm S, Ernst B. From a Library of MAG Antagonists to Nanomolar CD22 Ligands. ChemMedChem 2011; 7:134-43. [DOI: 10.1002/cmdc.201100407] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Indexed: 12/14/2022]
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10
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Development of photocrosslinked sialic acid containing polymers for use in Abeta toxicity attenuation. Biomaterials 2008; 29:3408-14. [PMID: 18508118 DOI: 10.1016/j.biomaterials.2008.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Accepted: 05/02/2008] [Indexed: 12/27/2022]
Abstract
beta-Amyloid peptide (Abeta), the primary protein component in senile plaques associated with Alzheimer's disease (AD), has been implicated in neurotoxicity associated with AD. Previous studies have shown that the Abeta-neuronal membrane interaction plays a crucial role in Abeta toxicity. More specifically, it is thought that Abeta interacts with ganglioside rich and sialic acid rich regions of cell surfaces. In light of such evidence, we have hypothesized that the Abeta-membrane sialic acid interaction could be inhibited through use of a biomimic multivalent sialic acid compound that would compete with the cell surface for Abeta binding. To explore this hypothesis, we synthesized a series of photocrosslinked sialic acid containing oligosaccharides and tested their ability to bind Abeta and attenuate Abeta toxicity in cell culture assays. We show that a polymer prepared via the photocrosslinking of disialyllacto-N-tetraose (DSLNT) was able to attenuate Abeta toxicity at low micromolar concentrations without adversely affecting the cell viability. Polymers prepared from mono-sialyl-oligosaccharides were less effective at Abeta toxicity attenuation. These results demonstrate the feasibility of using photocrosslinked sialyl-oligosaccharides for prevention of Abeta toxicity in vitro and may provide insight into the design of new materials for use in attenuation of Abeta toxicity associated with AD.
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11
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Collins BE, Blixt O, Han S, Duong B, Li H, Nathan JK, Bovin N, Paulson JC. High-affinity ligand probes of CD22 overcome the threshold set by cis ligands to allow for binding, endocytosis, and killing of B cells. THE JOURNAL OF IMMUNOLOGY 2006; 177:2994-3003. [PMID: 16920935 DOI: 10.4049/jimmunol.177.5.2994] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
CD22 (Siglec-2) is a key regulator of B cell signaling whose function is modulated by interaction with extracellular glycan ligands mediated through its N-terminal Ig domain. Its preferred ligand is the sequence Sia alpha2-6Gal that is abundantly expressed on N-linked glycans of B cell glycoproteins, and by binding to CD22 in cis causes CD22 to appear "masked" from binding to synthetic sialoside probes. Yet, despite the presence of cis ligands, CD22 redistributes to sites of cell contact by binding to trans ligands on neighboring cells. In this study, we demonstrate the dynamic equilibrium that exists between CD22 and its cis and trans ligands, using a high-affinity multivalent sialoside probe that competes with cis ligands and binds to CD22 on native human and murine B cells. Consistent with the constitutive endocytosis reported for CD22, the probes are internalized once bound, demonstrating that CD22 is an endocytic receptor that can carry ligand-decorated "cargo" to intracellular compartments. Conjugation of the sialoside probes to the toxin saporin resulted in toxin uptake and toxin-mediated killing of B lymphoma cell lines, suggesting an alternative approach for targeting CD22 for treatment of B cell lymphomas.
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Affiliation(s)
- Brian E Collins
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92024, USA
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12
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Blixt O, Collins BE, van den Nieuwenhof IM, Crocker PR, Paulson JC. Sialoside specificity of the siglec family assessed using novel multivalent probes: identification of potent inhibitors of myelin-associated glycoprotein. J Biol Chem 2003; 278:31007-19. [PMID: 12773526 DOI: 10.1074/jbc.m304331200] [Citation(s) in RCA: 175] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Ten of the 11 known human siglecs or their murine orthologs have been evaluated for their specificity for over 25 synthetic sialosides representing most of the major sequences terminating carbohydrate groups of glycoproteins and glycolipids. Analysis has been performed using a novel multivalent platform comprising biotinylated sialosides bound to a streptavidin-alkaline phosphatase conjugate. Each siglec was found to have a unique specificity for binding 16 different sialoside-streptavidin-alkaline phosphatase probes. The relative affinities of monovalent sialosides were assessed for each siglec in competitive inhibition studies. The quantitative data obtained allows a detailed analysis of each siglec for the relative importance of sialic acid and the penultimate oligosaccharide sequence on binding affinity and specificity. Most remarkable was the finding that myelin-associated glycoprotein (Siglec-4) binds with 500-10,000-fold higher affinity to a series of mono- and di-sialylated derivatives of the O-linked T-antigen (Galbeta(1-3)-GalNAc(alpha)OThr) as compared with alpha-methyl-NeuAc.
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MESH Headings
- Alkaline Phosphatase
- Animals
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Antigens, Differentiation, B-Lymphocyte/genetics
- Antigens, Differentiation, B-Lymphocyte/metabolism
- Antigens, Differentiation, Myelomonocytic/genetics
- Antigens, Differentiation, Myelomonocytic/metabolism
- CHO Cells
- Carbohydrate Sequence
- Cell Adhesion Molecules
- Chimera
- Cricetinae
- Enzyme-Linked Immunosorbent Assay
- Galactosides/chemical synthesis
- Galactosides/metabolism
- Glycolipids/chemical synthesis
- Glycolipids/metabolism
- Glycoproteins/chemical synthesis
- Glycoproteins/metabolism
- Humans
- Lectins/genetics
- Lectins/metabolism
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/metabolism
- Mice
- Molecular Sequence Data
- N-Acetylneuraminic Acid/metabolism
- Protein Binding
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Sialic Acid Binding Ig-like Lectin 1
- Sialic Acid Binding Ig-like Lectin 2
- Sialic Acid Binding Immunoglobulin-like Lectins
- Streptavidin
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Affiliation(s)
- Ola Blixt
- Scripps Research Institute, Department of Molecular Biology, La Jolla, California 92037, USA
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13
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Yang ZQ, Puffer EB, Pontrello JK, Kiessling LL. Synthesis of a multivalent display of a CD22-binding trisaccharide. Carbohydr Res 2002; 337:1605-13. [PMID: 12423961 DOI: 10.1016/s0008-6215(02)00270-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Multivalent interactions have been implicated in the binding of B-cell surface glycoprotein CD22 to its physiological ligands. Because CD22 can influence B-cell antigen receptor (BCR) signaling, multivalent ligands that cluster CD22 may influence B-cell responses. Here, we report an efficient synthesis of a fluorophore-labeled multivalent display of a CD22-binding trisaccharide, Neu5Acalpha2,6Galbeta1,4Glc, using the ring-opening metathesis polymerization (ROMP). Our synthetic strategy involves the modification of an N-hydroxysuccinimide (NHS) ester-substituted polymer generated by ROMP with the aminopropyl glycoside of the trisaccharide. The conjugation efficiency for the coupling is high; when 0.3 equiv of the trisaccharide derivative were used relative to NHS ester groups, the mole fraction (chi) of trisaccharide ligand incorporated onto the backbone was 0.3. A fluorescein-labeled version of the multivalent ligand binds to cells expressing CD22.
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Affiliation(s)
- Zhi-Qiang Yang
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
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14
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Buschiazzo A, Amaya MF, Cremona ML, Frasch AC, Alzari PM. The crystal structure and mode of action of trans-sialidase, a key enzyme in Trypanosoma cruzi pathogenesis. Mol Cell 2002; 10:757-68. [PMID: 12419220 DOI: 10.1016/s1097-2765(02)00680-9] [Citation(s) in RCA: 183] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Trans-sialidases (TS) are GPI-anchored surface enzymes expressed in specific developmental stages of trypanosome parasites like Trypanosoma cruzi, the etiologic agent of Chagas disease, and T. brucei, the causative agent of sleeping sickness. TS catalyzes the transfer of sialic acid residues from host to parasite glycoconjugates through a transglycosidase reaction that appears to be critical for T. cruzi survival and cell invasion capability. We report here the structure of the T. cruzi trans-sialidase, alone and in complex with sugar ligands. Sialic acid binding is shown to trigger a conformational switch that modulates the affinity for the acceptor substrate and concomitantly creates the conditions for efficient transglycosylation. The structure provides a framework for the structure-based design of novel inhibitors with potential therapeutic applications.
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Affiliation(s)
- Alejandro Buschiazzo
- Unité de Biochimie Structurale, CNRS URA 2185, Institut Pasteur, 25 rue du Dr. Roux, 75724, Paris, France
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15
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Collins BE, Blixt O, Bovin NV, Danzer CP, Chui D, Marth JD, Nitschke L, Paulson JC. Constitutively unmasked CD22 on B cells of ST6Gal I knockout mice: novel sialoside probe for murine CD22. Glycobiology 2002; 12:563-71. [PMID: 12213789 DOI: 10.1093/glycob/cwf067] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The interaction of CD22 with glycoprotein ligands bearing the Siaalpha2,6Gal-R sequence is believed to modulate its function as a regulator of B cell signaling. Although a commercial sialoside-polyacrylamide (PAA) probe, NeuAc- alpha2,6Gal-PAA, has facilitated studies on ligand binding by human CD22, murine CD22 binds instead with high affinity to NeuGcalpha2,6Gal-R. A multivalent probe with this sequence was constructed to facilitate investigations of ligand binding in CD22 function using genetically defined murine models. The probe is based on the sialoside-PAA platform, which is then biotinylated for easy detection. A series of sialoside probes were constructed with two different length linker arms between the sialoside and the backbone and three different sialoside to PAA molar ratios. The NeuGcalpha2,6Gal-PAA probe is specific for CD22: it binds to sialidase-treated B cells of wild-type mice but not B cells of CD22-null mice. Additionally, because the probe only binds to sialidase-treated wild-type cells, it confirms that CD22 is constitutively "masked" on most B cells from wild-type mice by binding to ligands in cis. In contrast, the probe bound equally well to native or sialidase-treated B cells from the immunocompromised ligand-deficient ST6Gal I knockout mice, demonstrating that CD22 is constitutively "unmasked" in these cells.
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Affiliation(s)
- Brian E Collins
- Department of Molecular Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd., MEM-L71, La Jolla, CA 92075, USA
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16
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Azuma Y, Sakanashi M, Matsumoto K. The effect of alpha2,6-linked sialic acid on anti-IgM antibody-induced apoptosis in Ramos cells. Glycoconj J 2001; 18:419-24. [PMID: 11925509 DOI: 10.1023/a:1014820316267] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Apoptosis in B cells is induced through the B cell antigen receptor (BCR) and affects the sialic acid recognition molecules on B cells. We investigated the effects of alpha(1)-acid glycoprotein (AGP), which mainly contains alpha2,6-linked sialic acid, on anti-IgM antibody (Ab)-induced apoptosis in Ramos cells, which are derived from Burkitt's lymphoma. When Ramos cells were incubated with anti-IgM-Ab in plates coated with AGP, neuraminidase-digested AGP (asAGP) or alpha2,3-sialylated AGP (2,3AGP), apoptosis was suppressed only in those coated with AGP. We also studied the effects of CD22, which is expressed on the surface of mature B cells and binds to sugar chains containing alpha2,6-linked sialic acid, with anti-CD22 monoclonal antibody (mAb). Anti-CD22mAb enhanced anti-IgM Ab-induced apoptosis in Ramos cells. These contradictory results suggested that the recognition molecules for alpha2,6-linked sialic acid on AGP, which inhibits B-cell apoptosis, is distinct from CD22, or that different binding domains of CD22 between alpha2,6-linked sialic acid and anti-CD22 mAb exert opposite functions of suppression or enhancement to anti-IgM Ab-induced B cells.
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MESH Headings
- Antibodies, Anti-Idiotypic/pharmacology
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/pharmacology
- Antigens, CD/immunology
- Antigens, CD/metabolism
- Antigens, Differentiation, B-Lymphocyte/immunology
- Antigens, Differentiation, B-Lymphocyte/metabolism
- Apoptosis/drug effects
- B-Lymphocytes/cytology
- B-Lymphocytes/drug effects
- B-Lymphocytes/immunology
- Carbohydrate Conformation
- Cell Adhesion Molecules
- Cell Survival/drug effects
- DNA Fragmentation/drug effects
- Flow Cytometry
- Humans
- Lectins
- N-Acetylneuraminic Acid/chemistry
- N-Acetylneuraminic Acid/pharmacology
- Orosomucoid/chemistry
- Orosomucoid/pharmacology
- Sialic Acid Binding Ig-like Lectin 2
- Tumor Cells, Cultured
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Affiliation(s)
- Y Azuma
- Department of Clinical Chemistry, School of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
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