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Conti G, Bärenwaldt A, Rabbani S, Mühlethaler T, Sarcevic M, Jiang X, Schwardt O, Ricklin D, Pieters RJ, Läubli H, Ernst B. Tetra- and Hexavalent Siglec-8 Ligands Modulate Immune Cell Activation. Angew Chem Int Ed Engl 2023; 62:e202314280. [PMID: 37947772 DOI: 10.1002/anie.202314280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/31/2023] [Accepted: 11/07/2023] [Indexed: 11/12/2023]
Abstract
Carbohydrate-binding proteins are generally characterized by poor affinities for their natural glycan ligands, predominantly due to the shallow and solvent-exposed binding sites. To overcome this drawback, nature has exploited multivalency to strengthen the binding by establishing multiple interactions simultaneously. The development of oligovalent structures frequently proved to be successful, not only for proteins with multiple binding sites, but also for proteins that possess a single recognition domain. Herein we present the syntheses of a number of oligovalent ligands for Siglec-8, a monomeric I-type lectin found on eosinophils and mast cells, alongside the thermodynamic characterization of their binding. While the enthalpic contribution of each binding epitope was within a narrow range to that of the monomeric ligand, the entropy penalty increased steadily with growing valency. Additionally, we observed a successful agonistic binding of the tetra- and hexavalent and, to an even larger extent, multivalent ligands to Siglec-8 on immune cells and modulation of immune cell activation. Thus, triggering a biological effect is not restricted to multivalent ligands but could be induced by low oligovalent ligands as well, whereas a monovalent ligand, despite binding with similar affinity, showed an antagonistic effect.
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Affiliation(s)
- Gabriele Conti
- Molecular Pharmacy Group, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
- Chemical Biology and Drug Discovery Group, Department of Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
| | - Anne Bärenwaldt
- Laboratory for Cancer Immunotherapy, Department of Biomedicine, University of Basel, Hebelstrasse 20, 4051, Basel, Switzerland
- Division of Medical Oncology, University Hospital Basel, Petersgraben 4, 4051, Basel, Switzerland
| | - Said Rabbani
- Molecular Pharmacy Group, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Tobias Mühlethaler
- Biophysics Facility, Department Biozentrum, University of Basel, Spitalstrasse 41, 4056, Basel, Switzerland
| | - Mirza Sarcevic
- Laboratory for Cancer Immunotherapy, Department of Biomedicine, University of Basel, Hebelstrasse 20, 4051, Basel, Switzerland
- Division of Medical Oncology, University Hospital Basel, Petersgraben 4, 4051, Basel, Switzerland
| | - Xiaohua Jiang
- Molecular Pharmacy Group, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Oliver Schwardt
- Molecular Pharmacy Group, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Daniel Ricklin
- Molecular Pharmacy Group, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Roland J Pieters
- Chemical Biology and Drug Discovery Group, Department of Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
| | - Heinz Läubli
- Laboratory for Cancer Immunotherapy, Department of Biomedicine, University of Basel, Hebelstrasse 20, 4051, Basel, Switzerland
- Division of Medical Oncology, University Hospital Basel, Petersgraben 4, 4051, Basel, Switzerland
| | - Beat Ernst
- Molecular Pharmacy Group, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
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2
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Cao Y, Rische CH, Bochner BS, O’Sullivan JA. Interactions between Siglec-8 and endogenous sialylated cis ligands restrain cell death induction in human eosinophils and mast cells. Front Immunol 2023; 14:1283370. [PMID: 37928558 PMCID: PMC10623328 DOI: 10.3389/fimmu.2023.1283370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 10/06/2023] [Indexed: 11/07/2023] Open
Abstract
Sialic acid-binding immunoglobulin-like lectin (Siglec)-8 is a sialoside-binding receptor expressed by eosinophils and mast cells that exhibits priming status- and cell type-dependent inhibitory activity. On eosinophils that have been primed with IL-5, GM-CSF, or IL-33, antibody ligation of Siglec-8 induces cell death through a pathway involving the β2 integrin-dependent generation of reactive oxygen species (ROS) via NADPH oxidase. In contrast, Siglec-8 engagement on mast cells inhibits cellular activation and mediator release but reportedly does not impact cell viability. The differences in responses between cytokine-primed and unprimed eosinophils, and between eosinophils and mast cells, to Siglec-8 ligation are not understood. We previously found that Siglec-8 binds to sialylated ligands present on the surface of the same cell (so-called cis ligands), preventing Siglec-8 ligand binding in trans. However, the functional relevance of these cis ligands has not been elucidated. We therefore explored the potential influence of cis ligands of Siglec-8 on both eosinophils and mast cells. De-sialylation using exogenous sialidase profoundly altered the consequences of Siglec-8 antibody engagement on both cell types, eliminating the need for cytokine priming of eosinophils to facilitate cell death and enabling Siglec-8-dependent mast cell death without impacting anti-Siglec-8 antibody binding. The cell death process licensed by de-sialylation resembled that characterized in IL-5-primed eosinophils, including CD11b upregulation, ROS production, and the activities of Syk, PI3K, and PLC. These results implicate cis ligands in restraining Siglec-8 function on eosinophils and mast cells and reveal a promising approach to the selective depletion of mast cells in patients with mast cell-mediated diseases.
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Affiliation(s)
- Yun Cao
- Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Clayton H. Rische
- Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
- Department of Biomedical Engineering, Northwestern University McCormick School of Engineering, Evanston, IL, United States
| | - Bruce S. Bochner
- Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Jeremy A. O’Sullivan
- Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
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3
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O'Sullivan JA, Youngblood BA, Schleimer RP, Bochner BS. Siglecs as potential targets of therapy in human mast cell- and/or eosinophil-associated diseases. Semin Immunol 2023; 69:101799. [PMID: 37413923 PMCID: PMC10528103 DOI: 10.1016/j.smim.2023.101799] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/08/2023]
Abstract
Siglecs (sialic acid-binding immunoglobulin-like lectins) are a family of vertebrate glycan-binding cell-surface proteins. The majority mediate cellular inhibitory activity once engaged by specific ligands or ligand-mimicking molecules. As a result, Siglec engagement is now of interest as a strategy to therapeutically dampen unwanted cellular responses. When considering allergic inflammation, human eosinophils and mast cells express overlapping but distinct patterns of Siglecs. For example, Siglec-6 is selectively and prominently expressed on mast cells while Siglec-8 is highly specific for both eosinophils and mast cells. This review will focus on a subset of Siglecs and their various endogenous or synthetic sialoside ligands that regulate eosinophil and mast cell function and survival. It will also summarize how certain Siglecs have become the focus of novel therapies for allergic and other eosinophil- and mast cell-related diseases.
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Affiliation(s)
- Jeremy A O'Sullivan
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | | | - Robert P Schleimer
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Bruce S Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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4
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Bochner BS, O'Sullivan JA, Chang AT, Youngblood BA. Siglecs in allergy and asthma. Mol Aspects Med 2023; 90:101104. [PMID: 35835621 PMCID: PMC10757266 DOI: 10.1016/j.mam.2022.101104] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/28/2022] [Accepted: 07/03/2022] [Indexed: 01/21/2023]
Abstract
The term "allergic diseases" encompasses several common, IgE-mediated conditions that range from being annoying to those that are life-threatening. Available treatments include active avoidance of the instigating allergen and the use of a variety of oral, inhaled, intranasal, intraocular and injected agents. While most individuals with allergies do well with existing therapies, there are still unmet therapeutic needs. Siglecs (sialic acid-binding, immunoglobulin-like lectins) are a family of single-pass transmembrane I-type lectins found on various subsets of cells, especially those of the immune system. All Siglecs have extracellular domains recognizing sialoside ligands, and most contain cytoplasmic domains with inhibitory signaling activity. This review focuses on Siglecs that likely play a role in regulating allergic and asthmatic responses, and how specific Siglecs, expressed on cells such as eosinophils and mast cells, are being targeted for therapeutic benefit.
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Affiliation(s)
- Bruce S Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
| | - Jeremy A O'Sullivan
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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Rana R, Rani S, Kumar V, Nakhate KT, Ajazuddin, Gupta U. Sialic Acid Conjugated Chitosan Nanoparticles: Modulation to Target Tumour Cells and Therapeutic Opportunities. AAPS PharmSciTech 2021; 23:10. [PMID: 34862568 DOI: 10.1208/s12249-021-02170-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 10/22/2021] [Indexed: 12/24/2022] Open
Abstract
Targeted delivery of therapeutics forestalls the dreadful delocalized effects, drug toxicities and needless immunosuppression. Cancer cells are bounteous with sialic acid and the differential expression of glycosyl transferase, glycosidase and monosaccharide transporter compared to healthy tissues. The current study entails the development and characterisation of sialic acid (SA)-labelled chitosan nanoparticles encapsulating gemcitabine (GEM). Chitosan (CS) was conjugated with SA using coupling reaction and characterised spectroscopically. Furthermore, different concentrations of chitosan and tripolyphosphate (TPP) were optimised to fabricate surface modified chitosan nanoparticles. SA conjugated chitosan nanoparticles encapsulating GEM (SA-CS_GEM NPs) of 232 ± 9.69 nm with narrow distribution (PDI < 0.5) and zeta potential of - 19 ± 0.97 mV was fabricated. GEM was successfully loaded in the SA-CS NPs, depicting prolonged and biphasic drug release pattern more elated at low pH. Pronounced cellular uptake (FITC tagged) and cytotoxicity (IC50 487.4 nM) was observed in SA-CS_GEM NPs against A549 cells. IC50 for SA-CS_GEM NPs plunged with an increase in the time points from 24 to 72 h. Concentration-dependent haemolytic study confirmed significant haemocompatibility of SA-CS_GEM NPs. Pharmacokinetic study was performed on Sprague-Dawley rats and the kinetic parameters were calculated using PKSolver 2.0. Results demonstrated a consequential refinement of 2.98 times in modified SA-CS_GEM NPs with a significant increase in retention time, bioavailability and elimination half-life, and decrease in elimination rate constant and volume of distribution in comparison to CS_GEM NPs. Therefore, SA-CS shell core nanoparticles could be a beneficial approach to target and treat NSCLC (non-small cell lung cancer) and direct for research possibilities to target the other tumour cells.
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Valent P, Degenfeld-Schonburg L, Sadovnik I, Horny HP, Arock M, Simon HU, Reiter A, Bochner BS. Eosinophils and eosinophil-associated disorders: immunological, clinical, and molecular complexity. Semin Immunopathol 2021; 43:423-438. [PMID: 34052871 PMCID: PMC8164832 DOI: 10.1007/s00281-021-00863-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 04/29/2021] [Indexed: 12/15/2022]
Abstract
Eosinophils and their mediators play a crucial role in various reactive states such as bacterial and viral infections, chronic inflammatory disorders, and certain hematologic malignancies. Depending on the underlying pathology, molecular defect(s), and the cytokine- and mediator-cascades involved, peripheral blood and tissue hypereosinophilia (HE) may develop and may lead to organ dysfunction or even organ damage which usually leads to the diagnosis of a HE syndrome (HES). In some of these patients, the etiology and impact of HE remain unclear. These patients are diagnosed with idiopathic HE. In other patients, HES is diagnosed but the etiology remains unknown — these patients are classified as idiopathic HES. For patients with HES, early therapeutic application of agents reducing eosinophil counts is usually effective in avoiding irreversible organ damage. Therefore, it is important to systematically explore various diagnostic markers and to correctly identify the disease elicitors and etiology. Depending on the presence and type of underlying disease, HES are classified into primary (clonal) HES, reactive HES, and idiopathic HES. In most of these patients, effective therapies can be administered. The current article provides an overview of the pathogenesis of eosinophil-associated disorders, with special emphasis on the molecular, immunological, and clinical complexity of HE and HES. In addition, diagnostic criteria and the classification of eosinophil disorders are reviewed in light of new developments in the field.
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Affiliation(s)
- Peter Valent
- Department of Internal Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Währinger Gürtel, 18-20 1090, Vienna, Austria. .,Ludwig Boltzmann Institute for Hematology and Oncology, Medical University of Vienna, Vienna, Austria.
| | - Lina Degenfeld-Schonburg
- Department of Internal Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Währinger Gürtel, 18-20 1090, Vienna, Austria
| | - Irina Sadovnik
- Department of Internal Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Währinger Gürtel, 18-20 1090, Vienna, Austria.,Ludwig Boltzmann Institute for Hematology and Oncology, Medical University of Vienna, Vienna, Austria
| | - Hans-Peter Horny
- Institute of Pathology, Ludwig Maximilian University, Munich, Germany
| | - Michel Arock
- Laboratory of Hematology, Pitié-Salpêtrière Hospital, Paris, France
| | - Hans-Uwe Simon
- Institute of Pharmacology, University of Bern, Bern, Switzerland.,Department of Clinical Immunology and Allergology, Sechenov University, Moscow, Russia.,Laboratory of Molecular Immunology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Andreas Reiter
- Department of Hematology and Oncology, University Hospital Mannheim, Heidelberg University, Mannheim, Germany
| | - Bruce S Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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7
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Discovery, Function, and Therapeutic Targeting of Siglec-8. Cells 2020; 10:cells10010019. [PMID: 33374255 PMCID: PMC7823959 DOI: 10.3390/cells10010019] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/18/2020] [Accepted: 12/20/2020] [Indexed: 12/11/2022] Open
Abstract
Siglecs (sialic acid-binding immunoglobulin-like lectins) are single-pass cell surface receptors that have inhibitory activities on immune cells. Among these, Siglec-8 is a CD33-related family member selectively expressed on human mast cells and eosinophils, and at low levels on basophils. These cells can participate in inflammatory responses by releasing mediators that attract or activate other cells, contributing to the pathogenesis of allergic and non-allergic diseases. Since its discovery in 2000, initial in vitro studies have found that the engagement of Siglec-8 with a monoclonal antibody or with selective polyvalent sialoglycan ligands induced the cell death of eosinophils and inhibited mast cell degranulation. Anti-Siglec-8 antibody administration in vivo to humanized and transgenic mice selectively expressing Siglec-8 on mouse eosinophils and mast cells confirmed the in vitro findings, and identified additional anti-inflammatory effects. AK002 (lirentelimab) is a humanized non-fucosylated IgG1 antibody against Siglec-8 in clinical development for mast cell- and eosinophil-mediated diseases. AK002 administration has safely demonstrated the inhibition of mast cell activity and the depletion of eosinophils in several phase 1 and phase 2 trials. This article reviews the discovery and functions of Siglec-8, and strategies for its therapeutic targeting for the treatment of eosinophil- and mast cell-associated diseases.
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8
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Kroezen BS, Conti G, Girardi B, Cramer J, Jiang X, Rabbani S, Müller J, Kokot M, Luisoni E, Ricklin D, Schwardt O, Ernst B. A Potent Mimetic of the Siglec-8 Ligand 6'-Sulfo-Sialyl Lewis x. ChemMedChem 2020; 15:1706-1719. [PMID: 32744401 DOI: 10.1002/cmdc.202000417] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Indexed: 12/15/2022]
Abstract
Siglecs are members of the immunoglobulin gene family containing sialic acid binding N-terminal domains. Among them, Siglec-8 is expressed on various cell types of the immune system such as eosinophils, mast cells and weakly on basophils. Cross-linking of Siglec-8 with monoclonal antibodies triggers apoptosis in eosinophils and inhibits degranulation of mast cells, making Siglec-8 a promising target for the treatment of eosinophil- and mast cell-associated diseases such as asthma. The tetrasaccharide 6'-sulfo-sialyl Lewisx has been identified as a specific Siglec-8 ligand in glycan array screening. Here, we describe an extended study enlightening the pharmacophores of 6'-sulfo-sialyl Lewisx and the successful development of a high-affinity mimetic. Retaining the neuraminic acid core, the introduction of a carbocyclic mimetic of the Gal moiety and a sulfonamide substituent in the 9-position gave a 20-fold improved binding affinity. Finally, the residence time, which usually is the Achilles tendon of carbohydrate/lectin interactions, could be improved.
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Affiliation(s)
- Blijke S Kroezen
- Molecular Pharmacy Group Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Gabriele Conti
- Molecular Pharmacy Group Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Benedetta Girardi
- Molecular Pharmacy Group Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Jonathan Cramer
- Molecular Pharmacy Group Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Xiaohua Jiang
- Molecular Pharmacy Group Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Said Rabbani
- Molecular Pharmacy Group Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Jennifer Müller
- Molecular Pharmacy Group Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Maja Kokot
- Molecular Pharmacy Group Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Enrico Luisoni
- Molecular Pharmacy Group Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Daniel Ricklin
- Molecular Pharmacy Group Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Oliver Schwardt
- Molecular Pharmacy Group Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Beat Ernst
- Molecular Pharmacy Group Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland
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9
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Knuplez E, Krier-Burris R, Cao Y, Marsche G, O’Sullivan J, Bochner BS. Frontline Science: Superior mouse eosinophil depletion in vivo targeting transgenic Siglec-8 instead of endogenous Siglec-F: Mechanisms and pitfalls. J Leukoc Biol 2020; 108:43-58. [PMID: 32134149 PMCID: PMC7585130 DOI: 10.1002/jlb.3hi0120-381r] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/30/2020] [Accepted: 02/05/2020] [Indexed: 01/02/2023] Open
Abstract
Eosinophils are important multifunctional granulocytes. When studying eosinophil function and its contribution to diseases, mouse models are often used. Mouse eosinophils selectively express sialic acid-binding immunoglobulin-like lectin (Siglec)-F. Its closest functional paralog on human eosinophils is Siglec-8. These Siglecs are being used to target eosinophils when exploring their mechanistic roles in disease and for potential therapeutic benefit. In order to facilitate preclinical studies of human Siglec-8, we developed transgenic mouse strains expressing human Siglec-8 only on the surface of eosinophils with or without endogenous Siglec-F and have begun characterizing various cellular functions in vitro and in vivo. Eosinophils from Siglec-8+ mice, with or without Siglec-F, responded to Siglec-8 antibody engagement in vitro by up-regulating surface CD11b, whereas Siglec-F antibody had no such effect. Engagement of Siglec-F or Siglec-8 with respective antibodies in vitro resulted in only modest increases in cell death. Administration of rat Siglec-F antibodies to mice led to a significant decrease in Siglec-F surface expression on eosinophils due to internalization, and thus appeared to decrease eosinophil numbers based on Siglec-F+ cells, but with proper gaiting strategies did not in fact result in significant eosinophil depletion. In marked contrast, administration of mouse Siglec-8 antibodies rapidly and effectively depleted eosinophils from blood and spleens of mice, but an F(ab')2 version did not, indicating an Fc-mediated mechanism for eosinophil depletion in vivo. Siglec-8 expressing mice with or without endogenous Siglec-F will be useful to study Siglec-8-based therapeutics, and may be a preferred approach when acute or chronic eosinophil depletion is needed.
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Affiliation(s)
- Eva Knuplez
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Division of Pharmacology, Otto Loewi Research Center, Medical University of Graz, Austria
| | - Rebecca Krier-Burris
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Yun Cao
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Gunther Marsche
- Division of Pharmacology, Otto Loewi Research Center, Medical University of Graz, Austria
| | - Jeremy O’Sullivan
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Bruce S. Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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10
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O'Sullivan JA, Chang AT, Youngblood BA, Bochner BS. Eosinophil and mast cell Siglecs: From biology to drug target. J Leukoc Biol 2020; 108:73-81. [PMID: 31965606 PMCID: PMC7531194 DOI: 10.1002/jlb.2mr0120-352rr] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/04/2020] [Accepted: 01/06/2020] [Indexed: 12/26/2022] Open
Abstract
Mast cells and eosinophils are innate immune cells involved in both acute and chronic inflammatory responses. Siglecs are a family of cell surface receptors that share sialic acid binding activity. Over the past 20 years, our knowledge of the expression and function of Siglecs on cells of the immune system and others has greatly expanded, as has our understanding of their signaling, ligands, and possible roles in disease pathophysiology. Because of this, Siglecs have garnered interest as potential drug targets using strategies ranging from biologics to ligand-directed nanoparticles. This mini-review will highlight the state of our knowledge regarding human eosinophil and mast cell Siglecs, their biology, what they recognize, tools developed for in vitro and preclinical experimentation, and the status of ongoing efforts to develop drugs that engage eosinophil and mast cell Siglecs for potential therapeutic benefit.
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Affiliation(s)
- Jeremy A O'Sullivan
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | | | | | - Bruce S Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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11
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Nycholat CM, Duan S, Knuplez E, Worth C, Elich M, Yao A, O'Sullivan J, McBride R, Wei Y, Fernandes SM, Zhu Z, Schnaar RL, Bochner BS, Paulson JC. A Sulfonamide Sialoside Analogue for Targeting Siglec-8 and -F on Immune Cells. J Am Chem Soc 2019; 141:14032-14037. [PMID: 31460762 DOI: 10.1021/jacs.9b05769] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Siglec family of cell surface receptors have emerged as attractive targets for cell-directed therapies due to their restricted expression on immune cells, endocytic properties, and ability to modulate receptor signaling. Human Siglec-8, for instance, has been identified as a therapeutic target for the treatment of eosinophil and mast cell disorders. A promising strategy to target Siglecs involves the use of liposomal nanoparticles with a multivalent display of Siglec ligands. A key challenge for this approach is the identification of a high affinity ligand for the target Siglec. Here, we report the development of a ligand of Siglec-8 and its closest murine functional orthologue Siglec-F that is capable of targeting liposomes to cells expressing Siglec-8 or -F. A glycan microarray library of synthetic 9-N-sulfonyl sialoside analogues was screened to identify potential lead compounds. The best ligand, 9-N-(2-naphthyl-sulfonyl)-Neu5Acα2-3-[6-O-sulfo]-Galβ1-4GlcNAc (6'-O-sulfo NSANeu5Ac) combined the lead 2-naphthyl sulfonyl C-9 substituent with the preferred sulfated scaffold. The ligand 6'-O-sulfo NSANeu5Ac was conjugated to lipids for display on liposomes to evaluate targeted delivery to cells. Targeted liposomes showed strong in vitro binding/uptake and selectivity to cells expressing Siglec-8 or -F and, when administered to mice, exhibit in vivo targeting to Siglec-F+ eosinophils.
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Affiliation(s)
- Corwin M Nycholat
- Department of Molecular Medicine , The Scripps Research Institute , La Jolla , California 92037 , United States
| | - Shiteng Duan
- Department of Molecular Medicine , The Scripps Research Institute , La Jolla , California 92037 , United States
| | - Eva Knuplez
- Department of Medicine, Division of Allergy and Immunology , Northwestern University Feinberg School of Medicine , Chicago , Illinois 60611 , United States
| | - Charli Worth
- Department of Molecular Medicine , The Scripps Research Institute , La Jolla , California 92037 , United States
| | - Mila Elich
- Department of Molecular Medicine , The Scripps Research Institute , La Jolla , California 92037 , United States
| | - Anzhi Yao
- Department of Molecular Medicine , The Scripps Research Institute , La Jolla , California 92037 , United States
| | - Jeremy O'Sullivan
- Department of Medicine, Division of Allergy and Immunology , Northwestern University Feinberg School of Medicine , Chicago , Illinois 60611 , United States
| | - Ryan McBride
- Department of Molecular Medicine , The Scripps Research Institute , La Jolla , California 92037 , United States
| | - Yadong Wei
- Section of Allergy and Clinical Immunology , Yale University School of Medicine , New Haven , Connecticut 06511 , United States
| | - Steve M Fernandes
- Department of Pharmacology and Molecular Sciences , Johns Hopkins University School of Medicine , Baltimore , Maryland 21205 , United States
| | - Zhou Zhu
- Section of Allergy and Clinical Immunology , Yale University School of Medicine , New Haven , Connecticut 06511 , United States
| | - Ronald L Schnaar
- Department of Pharmacology and Molecular Sciences , Johns Hopkins University School of Medicine , Baltimore , Maryland 21205 , United States
| | - Bruce S Bochner
- Department of Medicine, Division of Allergy and Immunology , Northwestern University Feinberg School of Medicine , Chicago , Illinois 60611 , United States
| | - James C Paulson
- Department of Molecular Medicine , The Scripps Research Institute , La Jolla , California 92037 , United States
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12
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Gonzalez-Gil A, Porell RN, Fernandes SM, Wei Y, Yu H, Carroll DJ, McBride R, Paulson JC, Tiemeyer M, Aoki K, Bochner BS, Schnaar RL. Sialylated keratan sulfate proteoglycans are Siglec-8 ligands in human airways. Glycobiology 2019; 28:786-801. [PMID: 29924315 PMCID: PMC6142871 DOI: 10.1093/glycob/cwy057] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 06/18/2018] [Indexed: 01/02/2023] Open
Abstract
Human siglecs are a family of 14 sialic acid-binding proteins, most of which are expressed on subsets of immune cells where they regulate immune responses. Siglec-8 is expressed selectively on human allergic inflammatory cells—primarily eosinophils and mast cells—where engagement causes eosinophil apoptosis and inhibits mast cell mediator release. Evidence supports a model in which human eosinophils and mast cells bind to Siglec-8 sialoglycan ligands on inflammatory target tissues to resolve allergic inflammation and limit tissue damage. To identify Siglec-8-binding sialoglycans from human airways, proteins extracted from postmortem human trachea were resolved by size-exclusion chromatography and composite agarose–acrylamide gel electrophoresis, blotted and probed by Siglec-8-Fc blot overlay. Three size classes of Siglec-8 ligands were identified: 250 kDa, 600 kDa and 1 MDa, each of which was purified by affinity chromatography using a recombinant pentameric form of Siglec-8. Proteomic mass spectrometry identified all size classes as the proteoglycan aggrecan, a finding validated by immunoblotting. Glycan array studies demonstrated Siglec-8 binding to synthetic glycans with a terminal Neu5Acα2-3(6-sulfo)-Gal determinant, a quantitatively minor terminus on keratan sulfate (KS) chains of aggrecan. Treating human tracheal extracts with sialidase or keratanase eliminated Siglec-8 binding, indicating sialylated KS chains as Siglec-8-binding determinants. Treating human tracheal histological sections with keratanase also completely eliminated the binding of Siglec-8-Fc. Finally, Siglec-8 ligand purified from human trachea extracts induced increased apoptosis of freshly isolated human eosinophils in vitro. We conclude that sialylated KS proteoglycans are endogenous human airway ligands that bind Siglec-8 and may regulate allergic inflammation.
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Affiliation(s)
- Anabel Gonzalez-Gil
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ryan N Porell
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Steve M Fernandes
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yadong Wei
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Huifeng Yu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Daniela J Carroll
- Department of Medicine, Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Ryan McBride
- Departments of Chemical Physiology, Cell and Molecular Biology, and Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, USA
| | - James C Paulson
- Departments of Chemical Physiology, Cell and Molecular Biology, and Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, USA
| | - Michael Tiemeyer
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Kazuhiro Aoki
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Bruce S Bochner
- Department of Medicine, Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Ronald L Schnaar
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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13
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Varricchi G, Raap U, Rivellese F, Marone G, Gibbs BF. Human mast cells and basophils-How are they similar how are they different? Immunol Rev 2019; 282:8-34. [PMID: 29431214 DOI: 10.1111/imr.12627] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mast cells and basophils are key contributors to allergies and other inflammatory diseases since they are the most prominent source of histamine as well as numerous additional inflammatory mediators which drive inflammatory responses. However, a closer understanding of their precise roles in allergies and other pathological conditions has been marred by the considerable heterogeneity that these cells display, not only between mast cells and basophils themselves but also across different tissue locations and species. While both cell types share the ability to rapidly degranulate and release histamine following high-affinity IgE receptor cross-linking, they differ markedly in their ability to either react to other stimuli, generate inflammatory eicosanoids or release immunomodulating cytokines and chemokines. Furthermore, these cells display considerable pharmacological heterogeneity which has stifled attempts to develop more effective anti-allergic therapies. Mast cell- and basophil-specific transcriptional profiling, at rest and after activation by innate and adaptive stimuli, may help to unravel the degree to which these cells differ and facilitate a clearer understanding of their biological functions and how these could be targeted by new therapies.
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Affiliation(s)
- Gilda Varricchi
- Department of Translational Medical Sciences and Center for Basic and Clinical Immunology Research, University of Naples Federico II, Naples, Italy.,WAO Center of Excellence, Naples, Italy
| | - Ulrike Raap
- Department of Dermatology and Allergology, University of Oldenburg, Oldenburg, Germany
| | - Felice Rivellese
- Department of Translational Medical Sciences and Center for Basic and Clinical Immunology Research, University of Naples Federico II, Naples, Italy.,WAO Center of Excellence, Naples, Italy.,Centre for Experimental Medicine and Rheumatology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Gianni Marone
- Department of Translational Medical Sciences and Center for Basic and Clinical Immunology Research, University of Naples Federico II, Naples, Italy.,WAO Center of Excellence, Naples, Italy.,Institute of Experimental Endocrinology and Oncology "Gaetano Salvatore" (IEOS), National Research Council (CNR), Naples, Italy
| | - Bernhard F Gibbs
- Department of Dermatology and Allergology, University of Oldenburg, Oldenburg, Germany
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14
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Wei Y, Chhiba KD, Zhang F, Ye X, Wang L, Zhang L, Robida PA, Moreno-Vinasco L, Schnaar RL, Roers A, Hartmann K, Lee CM, Demers D, Zheng T, Bochner BS, Zhu Z. Mast Cell-Specific Expression of Human Siglec-8 in Conditional Knock-in Mice. Int J Mol Sci 2018; 20:ijms20010019. [PMID: 30577572 PMCID: PMC6337227 DOI: 10.3390/ijms20010019] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 12/04/2018] [Accepted: 12/14/2018] [Indexed: 01/31/2023] Open
Abstract
Sialic acid-binding Ig-like lectin 8 (Siglec-8) is expressed on the surface of human eosinophils, mast cells, and basophils—cells that participate in allergic and other diseases. Ligation of Siglec-8 by specific glycan ligands or antibodies triggers eosinophil death and inhibits mast cell degranulation; consequences that could be leveraged as treatment. However, Siglec-8 is not expressed in murine and most other species, thus limiting preclinical studies in vivo. Based on a ROSA26 knock-in vector, a construct was generated that contains the CAG promoter, a LoxP-floxed-Neo-STOP fragment, and full-length Siglec-8 cDNA. Through homologous recombination, this Siglec-8 construct was targeted into the mouse genome of C57BL/6 embryonic stem (ES) cells, and chimeric mice carrying the ROSA26-Siglec-8 gene were generated. After cross-breeding to mast cell-selective Cre-recombinase transgenic lines (CPA3-Cre, and Mcpt5-Cre), the expression of Siglec-8 in different cell types was determined by RT-PCR and flow cytometry. Peritoneal mast cells (dual FcεRI+ and c-Kit+) showed the strongest levels of surface Siglec-8 expression by multicolor flow cytometry compared to expression levels on tissue-derived mast cells. Siglec-8 was seen on a small percentage of peritoneal basophils, but not other leukocytes from CPA3-Siglec-8 mice. Siglec-8 mRNA and surface protein were also detected on bone marrow-derived mast cells. Transgenic expression of Siglec-8 in mice did not affect endogenous numbers of mast cells when quantified from multiple tissues. Thus, we generated two novel mouse strains, in which human Siglec-8 is selectively expressed on mast cells. These mice may enable the study of Siglec-8 biology in mast cells and its therapeutic targeting in vivo.
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Affiliation(s)
- Yadong Wei
- Section of Allergy and Clinical Immunology, Yale University School of Medicine, New Haven, CT 06511, USA.
| | - Krishan D Chhiba
- Department of Medicine, Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
| | - Fengrui Zhang
- Section of Allergy and Clinical Immunology, Yale University School of Medicine, New Haven, CT 06511, USA.
| | - Xujun Ye
- Section of Allergy and Clinical Immunology, Yale University School of Medicine, New Haven, CT 06511, USA.
| | - Lihui Wang
- Section of Allergy and Clinical Immunology, Yale University School of Medicine, New Haven, CT 06511, USA.
| | - Li Zhang
- Section of Allergy and Clinical Immunology, Yale University School of Medicine, New Haven, CT 06511, USA.
| | - Piper A Robida
- Department of Medicine, Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
| | - Liliana Moreno-Vinasco
- Department of Medicine, Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
| | - Ronald L Schnaar
- Department of Pharmacology, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA.
| | - Axel Roers
- Institute of Immunology, University of Technology Dresden, 01069 Dresden, Germany.
| | - Karin Hartmann
- Department of Dermatology, University of Lübeck, 23538 Lübeck, Germany.
| | - Chang-Min Lee
- Department of Molecular Microbiology and Immunology, Department of Pediatrics, Brown University Alpert Medical School, Providence, RI 02912, USA.
| | - Delia Demers
- Department of Molecular Microbiology and Immunology, Department of Pediatrics, Brown University Alpert Medical School, Providence, RI 02912, USA.
| | - Tao Zheng
- Section of Allergy and Clinical Immunology, Yale University School of Medicine, New Haven, CT 06511, USA.
- Department of Molecular Microbiology and Immunology, Department of Pediatrics, Brown University Alpert Medical School, Providence, RI 02912, USA.
| | - Bruce S Bochner
- Department of Medicine, Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
| | - Zhou Zhu
- Section of Allergy and Clinical Immunology, Yale University School of Medicine, New Haven, CT 06511, USA.
- Department of Molecular Microbiology and Immunology, Department of Pediatrics, Brown University Alpert Medical School, Providence, RI 02912, USA.
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15
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Bornhöfft KF, Goldammer T, Rebl A, Galuska SP. Siglecs: A journey through the evolution of sialic acid-binding immunoglobulin-type lectins. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 86:219-231. [PMID: 29751010 DOI: 10.1016/j.dci.2018.05.008] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/04/2018] [Accepted: 05/04/2018] [Indexed: 05/11/2023]
Abstract
Siglecs (sialic acid-binding immunoglobulin-type lectins) are a family of immune regulatory receptors predominantly found on the cells of the hematopoietic system. A V-set Ig-like domain mediates the recognition of different sialylated glycoconjugates, which can lead to the activation or inhibition of the immune response, depending on the involved Siglecs. Siglecs are categorized into two subgroups: one including all CD33-related Siglecs and the other consisting of Siglec-1 (Sialoadhesin), Siglec-2 (CD22), Siglec-4 (myelin-associated glycoprotein, MAG) and Siglec-15. In contrast to the members of the CD33-related Siglecs, which share ∼50-99% sequence identity, Siglecs of the other subgroup show quite low homology (approximately 25-30% sequence identity). Based on the published sequences and functions of Siglecs, we performed phylogenetic analyses and sequence alignments to reveal the conservation of Siglecs throughout evolution. Therefore, we focused on the presence of Siglecs in different classes of vertebrates (fishes, amphibians, birds, reptiles and mammals), offering a bridge between the presence of different Siglecs and the biological situations of the selected animals.
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Affiliation(s)
- Kim F Bornhöfft
- Institute of Reproductive Biology, Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany
| | - Tom Goldammer
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany
| | - Alexander Rebl
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.
| | - Sebastian P Galuska
- Institute of Reproductive Biology, Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.
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16
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Issa SMA, Vitiazeva V, Hayes CA, Karlsson NG. Higher Energy Collisional Dissociation Mass Spectrometry of Sulfated O-Linked Oligosaccharides. J Proteome Res 2018; 17:3259-3267. [DOI: 10.1021/acs.jproteome.8b00376] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Samah M. A. Issa
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Box 440, Medicinaregatan 9A, 405 30 Gothenburg, Sweden
| | - Varvara Vitiazeva
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Box 440, Medicinaregatan 9A, 405 30 Gothenburg, Sweden
| | - Catherine A. Hayes
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Box 440, Medicinaregatan 9A, 405 30 Gothenburg, Sweden
| | - Niclas G. Karlsson
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Box 440, Medicinaregatan 9A, 405 30 Gothenburg, Sweden
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17
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O’Sullivan JA, Wei Y, Carroll DJ, Moreno-Vinasco L, Cao Y, Zhang F, Lee JJ, Zhu Z, Bochner BS. Frontline Science: Characterization of a novel mouse strain expressing human Siglec-8 only on eosinophils. J Leukoc Biol 2018; 104:11-19. [PMID: 29601103 PMCID: PMC6013361 DOI: 10.1002/jlb.2hi0917-391r] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 02/08/2018] [Accepted: 02/12/2018] [Indexed: 01/01/2023] Open
Abstract
Sialic acid-binding immunoglobulin-like lectin (Siglec)-8 is a human cell surface protein expressed exclusively on eosinophils, mast cells, and basophils that, when engaged, induces eosinophil apoptosis and inhibits mast cell mediator release. This makes Siglec-8 a promising therapeutic target to treat diseases involving these cell types. However, preclinical studies of Siglec-8 targeting in vivo are lacking because this protein is only found in humans, apes, and some monkeys. Therefore, we have developed a mouse strain in which SIGLEC8 transcription is activated by Cre recombinase and have crossed this mouse with the eoCre mouse to achieve eosinophil-specific expression. We confirmed that Siglec-8 is expressed exclusively on the surface of mature eosinophils in multiple tissues at levels comparable to those on human blood eosinophils. Following ovalbumin sensitization and airway challenge, Siglec-8 knock-in mice generated a pattern of allergic lung inflammation indistinguishable from that of littermate controls, suggesting that Siglec-8 expression within the eosinophil compartment does not alter allergic eosinophilic inflammation. Using bone marrow from these mice, we demonstrated that, during maturation, Siglec-8 expression occurs well before the late eosinophil developmental marker C-C motif chemokine receptor 3, consistent with eoCre expression. Antibody ligation of the receptor induces Siglec-8 endocytosis and alters the phosphotyrosine profile of these cells, indicative of productive signaling. Finally, we demonstrated that mouse eosinophils expressing Siglec-8 undergo cell death when the receptor is engaged, further evidence that Siglec-8 is functional on these cells. These mice should prove useful to investigate Siglec-8 biology and targeting in vivo in a variety of eosinophilic disease models.
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Affiliation(s)
- Jeremy A. O’Sullivan
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Yadong Wei
- Section of Allergy and Clinical Immunology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Daniela J. Carroll
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Liliana Moreno-Vinasco
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Yun Cao
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Fengrui Zhang
- Section of Allergy and Clinical Immunology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - James. J. Lee
- Division of Pulmonary Medicine, Department of Biochemistry and Molecular Biology, Mayo Clinic Arizona, Scottsdale, Arizona, USA
| | - Zhou Zhu
- Section of Allergy and Clinical Immunology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Bruce S. Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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18
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Yu H, Gonzalez-Gil A, Wei Y, Fernandes SM, Porell RN, Vajn K, Paulson JC, Nycholat CM, Schnaar RL. Siglec-8 and Siglec-9 binding specificities and endogenous airway ligand distributions and properties. Glycobiology 2018; 27:657-668. [PMID: 28369504 DOI: 10.1093/glycob/cwx026] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 03/15/2017] [Indexed: 01/15/2023] Open
Abstract
Siglecs are transmembrane sialoglycan binding proteins, most of which are expressed on leukocyte subsets and have inhibitory motifs that translate cell surface ligation into immune suppression. In humans, Siglec-8 on eosinophils, mast cells and basophils and Siglec-9 on neutrophils, monocytes and some T-cells, mediate immune cell death, inhibition of immune mediator release and/or enhancement of anti-inflammatory mediator release. Endogenous sialoglycan ligands in tissues, mostly uncharacterized, engage siglecs on leukocytes to inhibit inflammation. Glycan array analyses demonstrated that Siglec-8, Siglec-9 and their mouse counterparts Siglec-F and Siglec-E (respectively) have distinct glycan binding specificities, with Siglec-8 more structurally restricted. Since siglecs are involved in lung inflammation, we studied Siglec-8 and Siglec-9 ligands in human lungs and airways. Siglec-8 ligands are in tracheal submucosal glands and cartilage but not airway epithelium or connective tissues, whereas Siglec-9 ligands are broadly distributed. Mouse airways do not have Siglec-8 ligands, whereas Siglec-9 ligands are on airways of both species. Extraction of human airways and lung followed by electrophoretic resolution and siglec blotting revealed Siglec-8 ligands in extracts of human trachea and cultured tracheal gland cells, but not parenchyma or cultured airway epithelial cells whereas Siglec-9 ligands were extracted from all airway and lung tissues and cells tested. Siglec-8 and Siglec-9 ligands in airways appear to be high molecular weight O-linked sialoglycoproteins. These data reveal differential glycan specificities of Siglec-8, Siglec-9 and their mouse counterparts Siglec-F and Siglec-E, and the tissue distributions and molecular characteristics of Siglec-8 and Siglec-9 sialoglycan ligands on human airways and lungs.
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Affiliation(s)
- Huifeng Yu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N Wolfe St, Baltimore, MD 21205, USA
| | - Anabel Gonzalez-Gil
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N Wolfe St, Baltimore, MD 21205, USA
| | - Yadong Wei
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N Wolfe St, Baltimore, MD 21205, USA
| | - Steve M Fernandes
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N Wolfe St, Baltimore, MD 21205, USA
| | - Ryan N Porell
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N Wolfe St, Baltimore, MD 21205, USA
| | - Katarina Vajn
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N Wolfe St, Baltimore, MD 21205, USA
| | - James C Paulson
- Departments of Cell and Molecular Biology, Chemical Physiology, and Immunology and Microbial Science, The Scripps Research Institute, 10550 N Torrey Pines Road, La Jolla, CA 92037, USA
| | - Corwin M Nycholat
- Departments of Cell and Molecular Biology, Chemical Physiology, and Immunology and Microbial Science, The Scripps Research Institute, 10550 N Torrey Pines Road, La Jolla, CA 92037, USA
| | - Ronald L Schnaar
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N Wolfe St, Baltimore, MD 21205, USA
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19
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Wielgat P, Trofimiuk E, Czarnomysy R, Holownia A, Braszko JJ. Sialylation pattern in lung epithelial cell line and Siglecs expression in monocytic THP-1 cells as cellular indicators of cigarette smoke - induced pathology in vitro. Exp Lung Res 2018; 44:167-177. [PMID: 29781747 DOI: 10.1080/01902148.2018.1461959] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
PURPOSE Cellular response to cigarette smoke (CS) involves activation of recognition receptors resulting in changes in immune status, oxidative stress and cell turnover. We investigated the effects of CS on sialic acid-binding immunoglobulin type lectins (Siglecs) expression and their sialylated ligands in human immune and non-immune cells. METHODS Human monocytes (THP-1) and epithelial cells (A549) were cultured in CS-conditioned medium (CSM). Expression of Siglec-8 and Siglec-5/Siglec-14 was analysed in THP-1 cells using flow cytometry. The effects of CS on immune activity was evaluated flow cytometrically in these cells by assessment of phagocytosis and intracellular expression IL-1β and IL-10. Detection and differentiation of sialic acids was analyzed by dot blot, western blot and flow cytometry using plant lectins and antibodies. RESULTS Exposure to CS significantly increased expression of Siglec-8 and Siglec-5/Siglec-14 in THP-1 cells. These changes were accompanied by enhanced intracellular level of IL-1β and IL-10 but reduced phagocytic activity. In THP-1 and A549 cells, the level of α2,3-sialic acids, but not α2,6-sialic acid, was significantly increased when compared to naïve cells. The level of α2,8-sialic acids increased significantly in A549 cells, but not in THP-1 cells, after exposure to CS. CONCLUSION These results show that cellular response to CS involves changes in expression of Siglec receptors and sialylated ligands functionally associated with immunity.
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Affiliation(s)
- Przemyslaw Wielgat
- a Department of Clinical Pharmacology , Medical University of Bialystok , Bialystok , Poland
| | - Emil Trofimiuk
- a Department of Clinical Pharmacology , Medical University of Bialystok , Bialystok , Poland
| | - Robert Czarnomysy
- b Department of Synthesis and Technology of Drugs , Medical University of Bialystok , Bialystok , Poland
| | - Adam Holownia
- c Department of Pharmacology , Medical University of Bialystok , Bialystok , Poland
| | - Jan J Braszko
- a Department of Clinical Pharmacology , Medical University of Bialystok , Bialystok , Poland
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20
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Abdala-Valencia H, Coden ME, Chiarella SE, Jacobsen EA, Bochner BS, Lee JJ, Berdnikovs S. Shaping eosinophil identity in the tissue contexts of development, homeostasis, and disease. J Leukoc Biol 2018; 104:95-108. [PMID: 29656559 DOI: 10.1002/jlb.1mr1117-442rr] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 02/16/2018] [Accepted: 02/17/2018] [Indexed: 12/20/2022] Open
Abstract
Eosinophils play homeostatic roles in different tissues and are found in several organs at a homeostatic baseline, though their tissue numbers increase significantly in development and disease. The morphological, phenotypical, and functional plasticity of recruited eosinophils are influenced by the dynamic tissue microenvironment changes between homeostatic, morphogenetic, and disease states. Activity of the epithelial-mesenchymal interface, extracellular matrix, hormonal inputs, metabolic state of the environment, as well as epithelial and mesenchymal-derived innate cytokines and growth factors all have the potential to regulate the attraction, retention, in situ hematopoiesis, phenotype, and function of eosinophils. This review examines the reciprocal relationship between eosinophils and such tissue factors, specifically addressing: (1) tissue microenvironments associated with the presence and activity of eosinophils; (2) non-immune tissue ligands regulatory for eosinophil accumulation, hematopoiesis, phenotype, and function (with an emphasis on the extracellular matrix and epithelial-mesenchymal interface); (3) the contribution of eosinophils to regulating tissue biology; (4) eosinophil phenotypic heterogeneity in different tissue microenvironments, classifying eosinophils as progenitors, steady state eosinophils, and Type 1 and 2 activated phenotypes. An appreciation of eosinophil regulation by non-immune tissue factors is necessary for completing the picture of eosinophil immune activation and understanding the functional contribution of these cells to development, homeostasis, and disease.
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Affiliation(s)
- Hiam Abdala-Valencia
- Division of Pulmonary and Critical Care, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Mackenzie E Coden
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Sergio E Chiarella
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Elizabeth A Jacobsen
- Department of Biochemistry and Molecular Biology, Mayo Clinic Arizona, Scottsdale, Arizona, USA
| | - Bruce S Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - James J Lee
- Department of Biochemistry and Molecular Biology, Mayo Clinic Arizona, Scottsdale, Arizona, USA
| | - Sergejs Berdnikovs
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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21
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Bolden JE, Lucas EC, Zhou G, O'Sullivan JA, de Graaf CA, McKenzie MD, Di Rago L, Baldwin TM, Shortt J, Alexander WS, Bochner BS, Ritchie ME, Hilton DJ, Fairfax KA. Identification of a Siglec-F+ granulocyte-macrophage progenitor. J Leukoc Biol 2018; 104:123-133. [PMID: 29645346 PMCID: PMC6320667 DOI: 10.1002/jlb.1ma1217-475r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 02/14/2018] [Accepted: 02/16/2018] [Indexed: 01/09/2023] Open
Abstract
In recent years multi-parameter flow cytometry has enabled identification of cells at major stages in myeloid development; from pluripotent hematopoietic stem cells, through populations with increasingly limited developmental potential (common myeloid progenitors and granulocyte-macrophage progenitors), to terminally differentiated mature cells. Myeloid progenitors are heterogeneous, and the surface markers that define transition states from progenitors to mature cells are poorly characterized. Siglec-F is a surface glycoprotein frequently used in combination with IL-5 receptor alpha (IL5Rα) for the identification of murine eosinophils. Here, we describe a CD11b+ Siglec-F+ IL5Rα- myeloid population in the bone marrow of C57BL/6 mice. The CD11b+ Siglec-F+ IL5Rα- cells are retained in eosinophil deficient PHIL mice, and are not expanded upon overexpression of IL-5, indicating that they are upstream or independent of the eosinophil lineage. We show these cells to have GMP-like developmental potential in vitro and in vivo, and to be transcriptionally distinct from the classically described GMP population. The CD11b+ Siglec-F+ IL5Rα- population expands in the bone marrow of Myb mutant mice, which is potentially due to negative transcriptional regulation of Siglec-F by Myb. Lastly, we show that the role of Siglec-F may be, at least in part, to regulate GMP viability.
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Affiliation(s)
- Jessica E Bolden
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Erin C Lucas
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Geyu Zhou
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Jeremy A O'Sullivan
- Division of Allergy and Immunology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Carolyn A de Graaf
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Mark D McKenzie
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Ladina Di Rago
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Tracey M Baldwin
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Jake Shortt
- School of Clinical Sciences at Monash Health, Monash University, Clayton, Victoria, Australia
| | - Warren S Alexander
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Bruce S Bochner
- Division of Allergy and Immunology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Matthew E Ritchie
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Douglas J Hilton
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Kirsten A Fairfax
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
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Sialic acid-binding immunoglobulin-like lectin 8 (Siglec-8) is an activating receptor mediating β 2-integrin-dependent function in human eosinophils. J Allergy Clin Immunol 2017; 141:2196-2207. [PMID: 28888781 DOI: 10.1016/j.jaci.2017.08.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 08/01/2017] [Accepted: 08/28/2017] [Indexed: 12/30/2022]
Abstract
BACKGROUND Siglec-8 is a CD33 subfamily cell-surface receptor selectively expressed on human eosinophils. After cytokine priming, Siglec-8 mAb or glycan ligand binding causes eosinophil apoptosis associated with reactive oxygen species (ROS) production. Most CD33-related Siglecs function as inhibitory receptors, but the ability of Siglec-8 to stimulate eosinophil ROS production and apoptosis suggests that Siglec-8 might instead function as an activating receptor. OBJECTIVE We sought to determine the role of IL-5 priming and identify the signaling molecules involved in Siglec-8 function for human eosinophils. METHODS We used an mAb and/or a multimeric synthetic sulfated sialoglycan ligand recognizing Siglec-8 in combination with integrin blocking antibodies, pharmacologic inhibitors, phosphoproteomics, and Western blot analysis to define the necessity of various proteins involved in Siglec-8 function for human eosinophils. RESULTS Cytokine priming was required to elicit the unanticipated finding that Siglec-8 engagement promotes rapid β2-integrin-dependent eosinophil adhesion. Also novel was the finding that this adhesion was necessary for subsequent ROS production and apoptosis. Siglec-8-mediated ROS was generated through reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation because pretreatment of eosinophils with catalase (an extracellular superoxide scavenger) or NSC 23766 (a Rac GTPase inhibitor) completely inhibited Siglec-8-mediated eosinophil apoptosis. Finally, engagement of Siglec-8 on IL-5-primed eosinophils resulted in increased phosphorylation of Akt, p38, and c-Jun N-terminal kinase 1 that was also β2-integrin dependent; pharmacologic inhibition of these kinases completely prevented Siglec-8-mediated eosinophil apoptosis. CONCLUSIONS These data demonstrate that Siglec-8 functions uniquely as an activating receptor on IL-5-primed eosinophils through a novel pathway involving regulation of β2-integrin-dependent adhesion, NADPH oxidase, and a subset of protein kinases.
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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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O’Sullivan JA, Carroll DJ, Bochner BS. Glycobiology of Eosinophilic Inflammation: Contributions of Siglecs, Glycans, and Other Glycan-Binding Proteins. Front Med (Lausanne) 2017; 4:116. [PMID: 28824909 PMCID: PMC5539825 DOI: 10.3389/fmed.2017.00116] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 07/10/2017] [Indexed: 12/31/2022] Open
Abstract
The historical focus on protein-protein interactions in biological systems, at the expense of attention given to interactions between other classes of molecules, has overlooked important and clinically relevant processes and points of potential clinical intervention. For example, the significance of protein-carbohydrate interactions, especially in the regulation of immune responses, has recently received greater recognition and appreciation. This review discusses several ways by which cell-surface lectin-glycan interactions can modulate eosinophil function, particularly at the levels of eosinophil recruitment and survival, and how such interactions can be exploited therapeutically. A primary focus is on discoveries concerning Siglec-8, a glycan-binding protein selectively expressed on human eosinophils, and its closest functional paralog in the mouse, Siglec-F. Recent advances in the synthesis of polymeric ligands, the identification of physiological ligands for Siglec-8 and Siglec-F in the airway, and the determination of the basis of glycan ligand discrimination of Siglec-8 are discussed. Important similarities and differences between these siglecs are outlined. Eosinophil expression of additional glycan-binding proteins or their glycan ligands, including interactions involving members of the selectin, galectin, and siglec families, is summarized. The roles of these molecules in eosinophil recruitment, survival, and inflammation are described. Finally, the modulation of these interactions and potential therapeutic exploitation of glycan-binding proteins and their ligands to ameliorate eosinophil-associated diseases are considered.
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Affiliation(s)
- Jeremy A. O’Sullivan
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Daniela J. Carroll
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Bruce S. Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
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25
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Leveraging Siglec-8 endocytic mechanisms to kill human eosinophils and malignant mast cells. J Allergy Clin Immunol 2017; 141:1774-1785.e7. [PMID: 28734845 DOI: 10.1016/j.jaci.2017.06.028] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 06/01/2017] [Accepted: 06/12/2017] [Indexed: 01/06/2023]
Abstract
BACKGROUND Sialic acid-binding immunoglobulin-like lectin (Siglec)-8 is a cell-surface protein expressed selectively on human eosinophils, mast cells, and basophils, making it an ideal target for the treatment of diseases involving these cell types. However, the effective delivery of therapeutic agents to these cells requires an understanding of the dynamics of Siglec-8 surface expression. OBJECTIVES We sought to determine whether Siglec-8 is endocytosed in human eosinophils and malignant mast cells, identify mechanisms underlying its endocytosis, and demonstrate whether a toxin can be targeted to Siglec-8-bearing cells to kill these cells. METHODS Siglec-8 surface dynamics were examined by flow cytometry using peripheral blood eosinophils, mast cell lines, and Siglec-8-transduced cells in the presence of inhibitors targeting components of endocytic pathways. Siglec-8 intracellular trafficking was followed by confocal microscopy. The ribosome-inhibiting protein saporin was conjugated to a Siglec-8-specific antibody to examine the targeting of an agent to these cells through Siglec-8 endocytosis. RESULTS Siglec-8 endocytosis required actin rearrangement, tyrosine kinase and protein kinase C activities, and both clathrin and lipid rafts. Internalized Siglec-8 localized to the lysosomal compartment. Maximal endocytosis in Siglec-8-transduced HEK293T cells required an intact immunoreceptor tyrosine-based inhibitory motif. Siglec-8 was also shuttled to the surface via a distinct pathway. Sialidase treatment of eosinophils revealed that Siglec-8 is partially masked by sialylated cis ligands. Targeting saporin to Siglec-8 consistently caused extensive cell death in eosinophils and the human mast cell leukemia cell line HMC-1.2. CONCLUSIONS Therapeutic payloads can be targeted selectively to eosinophils and malignant mast cells by exploiting this Siglec-8 endocytic pathway.
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Regulation of airway inflammation by Siglec-8 and Siglec-9 sialoglycan ligand expression. Curr Opin Allergy Clin Immunol 2016; 16:24-30. [PMID: 26694037 DOI: 10.1097/aci.0000000000000234] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Inflammatory cells involved in the allergic response, including eosinophils, mast cells, basophils, and neutrophils, express sialoglycan-binding proteins such as Siglec-8 and Siglec-9, which inhibit cell function and survival. The purpose of this review is to briefly discuss the biology of these siglecs and their ligands and consider their potential impact in pathology and treatment of chronic rhinosinusitis (CRS). RECENT FINDINGS Recent studies demonstrate the presence of ligands for Siglec-8 and Siglec-9 in sinonasal tissue from patients with CRS as well as healthy patients, suggesting that the immunoregulatory functions of siglecs may be triggered in sinus tissue in health and disease. SUMMARY Ligands for Siglec-8 and Siglec-9 may regulate the function of eosinophils, mast cells, neutrophils, and other cells in sinus mucosa. Therapeutic strategies that activate the anti-inflammatory effects of siglecs may dampen inflammation and disease in CRS patients.
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Regulation of Siglec-8-induced intracellular reactive oxygen species production and eosinophil cell death by Src family kinases. Immunobiology 2016; 222:343-349. [PMID: 27682013 DOI: 10.1016/j.imbio.2016.09.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 09/13/2016] [Accepted: 09/17/2016] [Indexed: 01/21/2023]
Abstract
RATIONALE Siglec-8 is a surface receptor predominantly expressed on human eosinophils where its ligation induces reactive oxygen species (ROS) formation and cell death. Since Siglec-8 has intracellular tyrosine-based motifs, we hypothesized that Src family kinases (SFKs) are involved in ROS formation and cell death induced by Siglec-8 engagement. METHODS Human peripheral blood eosinophils were purified and incubated with anti-Siglec-8 monoclonal antibodies (mAb, agonist), IL-5, and SFK pharmacological inhibitors. We focused on Siglec-8-induced cell death in short-term IL-5-activated cells leading to a regulated necrosis-type cell death. ROS production was determined by dihydrorhodamine (DHR) 123 labeling and flow cytometry, or by chemiluminescence using Amplex red. Activation of SFK was determined using phospholuminex and Western blotting. RESULTS In order to determine cellular localization of ROS production, we measured intra and extracellular ROS. While an ETosis stimulus (calcium ionophore A23187) led to extracellular ROS (ecROS) production, Siglec-8-engagement in short-term IL-5 activated cells led to intracellular ROS (icROS) accumulation. Consistently, inhibition of extracellular ROS by catalase inhibited ETosis, but not IL-5-primed Siglec-8-induced cell death. In order to determine signaling events for Siglec-8, we performed Western blotting and found SFK phosphorylation in lysates from eosinophils stimulated with anti-Siglec-8 mAb±IL-5. In order to identify which SFKs were involved, we used the phospholuminex assay and found increased levels of phosphorylated Fgr in the cytoplasmic fraction of cells co-stimulated with anti-Siglec-8 and IL-5 for 3 hours compared with cells stimulated with IL-5 alone. To test the involvement of SFKs in ROS production and cell death, we used SFK inhibitors PP2 and dasatinib, both of which completely inhibited eosinophil ROS production and cell death induced by anti-Siglec-8 and IL-5 co-stimulation. CONCLUSION Siglec-8 engagement in short-term IL-5-activated eosinophils causes icROS production and SKF phosphorylation, and both are essential in mediating Siglec-8-induced cell death.
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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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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: 107] [Impact Index Per Article: 13.4] [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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30
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Santra A, Yu H, Tasnima N, Muthana MM, Li Y, Zeng J, Kenyond NJ, Louie AY, Chen X. Systematic Chemoenzymatic Synthesis of O-Sulfated Sialyl Lewis x Antigens. Chem Sci 2016; 7:2827-2831. [PMID: 28138383 PMCID: PMC5269574 DOI: 10.1039/c5sc04104j] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 12/14/2015] [Indexed: 11/21/2022] Open
Abstract
O-Sulfated sialyl Lewis x antigens play important roles in nature. However, due to their structural complexity, they are not readily accessible by either chemical or enzymatic synthetic processes. Taking advantage of a bacterial sialyltransferase mutant that can catalyze the transfer of different sialic acid forms from the corresponding sugar nucleotide donors to Lewis x antigens which are fucosylated glycans as well as an efficient one-pot multienzyme (OPME) sialylation system, O-sulfated sialyl Lewis x antigens containing different sialic acid forms and O-sulfation at different locations were systematically synthesized by chemoenzymatic methods.
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Affiliation(s)
- Abhishek Santra
- Department of Chemistry, University of California, Davis One Shields Avenue, Davis, CA 95616 (USA)
| | - Hai Yu
- Department of Chemistry, University of California, Davis One Shields Avenue, Davis, CA 95616 (USA)
| | - Nova Tasnima
- Department of Chemistry, University of California, Davis One Shields Avenue, Davis, CA 95616 (USA)
| | - Musleh M Muthana
- Department of Chemistry, University of California, Davis One Shields Avenue, Davis, CA 95616 (USA)
| | - Yanhong Li
- Department of Chemistry, University of California, Davis One Shields Avenue, Davis, CA 95616 (USA)
| | - Jie Zeng
- Department of Chemistry, University of California, Davis One Shields Avenue, Davis, CA 95616 (USA) ; School of Food Science, Henan Institute of Science and Technology, Xinxiang, 453003 (China)
| | - Nicholas J Kenyond
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, University of California, Davis, CA 95616 (USA)
| | - Angelique Y Louie
- Department of Biomedical Engineering, University of California, Davis, CA 95616 (USA)
| | - Xi Chen
- Department of Chemistry, University of California, Davis One Shields Avenue, Davis, CA 95616 (USA)
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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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32
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Bochner BS. "Siglec"ting the allergic response for therapeutic targeting. Glycobiology 2016; 26:546-52. [PMID: 26911285 DOI: 10.1093/glycob/cww024] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 02/20/2016] [Indexed: 01/09/2023] Open
Abstract
As a physician-scientist, I have pursued research related to translational immunology with the goal of improving our ability to diagnose and treat allergic, immunologic and other diseases involving eosinophils, basophils and mast cells. We have tried to delineate novel mechanisms of human disease, working whenever possible with primary human cells and tissues, attempting to identify targets that might be amenable to the development of new therapies. As a general strategy, we have compared eosinophils, basophils, mast cells and neutrophils to look for pathways in inflammation that were unique to distinct subsets of these cells. In doing so, the concepts of glycobiology did not enter my mind until we began noticing some intriguing functional differences involving selectins and their ligands among these cell types. One simple observation, that neutrophils were coated with a glycan that allowed them to interact with an endothelial adhesion molecule while eosinophils lacked this structure, pried open the glyco-door for me. Fruitful collaborations with card-carrying glycobiologists soon followed that have forever positively influenced our science, and have enhanced our hypotheses, experimental design, research opportunities and discoveries. Within a few years, we helped to discover Siglec-8, an I-type lectin expressed only on human eosinophils, basophils, mast cells. This receptor, together with its closest mouse counterpart Siglec-F, has been the primary focus of our work now for over a decade. If not for those in the fields of glycobiology and glycoimmunology, my lab would not have made much progress toward the goal of leveraging Siglec-8 for therapeutic purposes.
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Affiliation(s)
- Bruce S Bochner
- Department of Medicine, Division of Allergy-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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Angata T, Nycholat CM, Macauley MS. Therapeutic Targeting of Siglecs using Antibody- and Glycan-Based Approaches. Trends Pharmacol Sci 2015; 36:645-660. [PMID: 26435210 PMCID: PMC4593978 DOI: 10.1016/j.tips.2015.06.008] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 06/24/2015] [Accepted: 06/25/2015] [Indexed: 01/01/2023]
Abstract
The sialic acid-binding immunoglobulin-like lectins (Siglecs) are a family of immunomodulatory receptors whose functions are regulated by their glycan ligands. Siglecs are attractive therapeutic targets because of their cell type-specific expression pattern, endocytic properties, high expression on certain lymphomas/leukemias, and ability to modulate receptor signaling. Siglec-targeting approaches with therapeutic potential encompass antibody- and glycan-based strategies. Several antibody-based therapies are in clinical trials and continue to be developed for the treatment of lymphoma/leukemia and autoimmune disease, while the therapeutic potential of glycan-based strategies for cargo delivery and immunomodulation is a promising new approach. Here we review these strategies with special emphasis on emerging approaches and disease areas that may benefit from targeting the Siglec family.
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Affiliation(s)
- Takashi Angata
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Corwin M Nycholat
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Matthew S Macauley
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, USA.
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Bochner BS, Zimmermann N. Role of siglecs and related glycan-binding proteins in immune responses and immunoregulation. J Allergy Clin Immunol 2015; 135:598-608. [PMID: 25592986 DOI: 10.1016/j.jaci.2014.11.031] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 11/14/2014] [Accepted: 11/25/2014] [Indexed: 12/16/2022]
Abstract
Virtually all cells and extracellular material are heavily decorated by various glycans, yet our understanding of the structure and function of these moieties lags behind the understanding of nucleic acids, lipids, and proteins. Recent years have seen a tremendous acceleration of knowledge in the field of glycobiology, revealing many intricacies and functional contributions that were previously poorly appreciated or even unrecognized. This review highlights several topics relevant to glycoimmunology in which mammalian and pathogen-derived glycans displayed on glycoproteins and other scaffolds are recognized by specific glycan-binding proteins (GBPs), leading to a variety of proinflammatory and anti-inflammatory cellular responses. The focus for this review is mainly on 2 families of GBPs, sialic acid-binding immunoglobulin-like lectins (siglecs) and selectins, that are involved in multiple steps of the immune response, including distinguishing pathogens from self, cell trafficking to sites of inflammation, fine-tuning of immune responses leading to activation or tolerance, and regulation of cell survival. Importantly for the clinician, accelerated rates of discovery in the field of glycoimmunology are being translated into innovative medical approaches that harness the interaction of glycans and GBPs to the benefit of the host and might soon lead to novel diagnostics and therapeutics.
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Affiliation(s)
- Bruce S Bochner
- Department of Medicine, Division of Allergy-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Ill.
| | - Nives Zimmermann
- Department of Pediatrics, Division of Allergy and Immunology, Children's Hospital Medical Center, and Department of Pathology, University of Cincinnati College of Medicine, Cincinnati, Ohio
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35
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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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Molecular targets on mast cells and basophils for novel therapies. J Allergy Clin Immunol 2014; 134:530-44. [DOI: 10.1016/j.jaci.2014.03.007] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/24/2014] [Accepted: 03/07/2014] [Indexed: 01/14/2023]
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McMillan SJ, Richards HE, Crocker PR. Siglec-F-dependent negative regulation of allergen-induced eosinophilia depends critically on the experimental model. Immunol Lett 2014; 160:11-16. [PMID: 24698729 PMCID: PMC4045373 DOI: 10.1016/j.imlet.2014.03.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 03/11/2014] [Accepted: 03/21/2014] [Indexed: 12/19/2022]
Abstract
Siglec-F-dependent negative regulation of eosinophilia depends on experimental model. Siglec-F-dependent suppression of lung eosinophilia may not depend on ligand-induced apoptosis. Implications for therapeutic approaches to treating human disease in which siglec-8, is targeted.
Siglec-8 and siglec-F are paralogous membrane proteins expressed on human and murine eosinophils respectively. They bind similar sialylated and sulphated glycans and mediate eosinophil apoptosis when cross-linked with antibodies or glycan ligands. In models of allergic eosinophilic airway inflammation, siglec-F was shown previously to be important for negatively regulating eosinophilia. It was proposed that this was due to siglec-F-dependent apoptosis, triggered via engagement with ligands that are upregulated on bronchial epithelium. Our aim was to further investigate the functions of siglec-F by comparing two commonly used models of ovalbumin-induced airway inflammation that differ in the dose and route of administration of ovalbumin. In confirmation of published results, siglec-F-deficient mice had enhanced lung tissue eosinophilia in response to intranasal ovalbumin delivered every other day. However, following aerosolised ovalbumin delivered daily, there was no influence of siglec-F deficiency on lung eosinophilia. Expression of siglec-F ligands in lung tissues was similar in both models of allergen induced inflammation. These data demonstrate that siglec-F-dependent regulation of eosinophilia is subtle and depends critically on the model used. The findings also indicate that mechanisms other than ligand-induced apoptosis may be important in siglec-F-dependent suppression of eosinophilia.
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Affiliation(s)
- Sarah J McMillan
- Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Dundee, Scotland, UK, DD1 5EH
| | - Hannah E Richards
- Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Dundee, Scotland, UK, DD1 5EH
| | - Paul R Crocker
- Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Dundee, Scotland, UK, DD1 5EH.
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Patnode ML, Cheng CW, Chou CC, Singer MS, Elin MS, Uchimura K, Crocker PR, Khoo KH, Rosen SD. Galactose 6-O-sulfotransferases are not required for the generation of Siglec-F ligands in leukocytes or lung tissue. J Biol Chem 2013; 288:26533-45. [PMID: 23880769 PMCID: PMC3772201 DOI: 10.1074/jbc.m113.485409] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/21/2013] [Indexed: 12/17/2022] Open
Abstract
Eosinophil accumulation is a characteristic feature of the immune response to parasitic worms and allergens. The cell surface carbohydrate-binding receptor Siglec-F is highly expressed on eosinophils and negatively regulates their accumulation during inflammation. Although endogenous ligands for Siglec-F have yet to be biochemically defined, binding studies using glycan arrays have implicated galactose 6-O-sulfate (Gal6S) as a partial recognition determinant for this receptor. Only two sulfotransferases are known to generate Gal6S, namely keratan sulfate galactose 6-O-sulfotransferase (KSGal6ST) and chondroitin 6-O-sulfotransferase 1 (C6ST-1). Here we use mice deficient in both KSGal6ST and C6ST-1 to determine whether these sulfotransferases are required for the generation of endogenous Siglec-F ligands. First, we characterize ligand expression on leukocyte populations and find that ligands are predominantly expressed on cell types also expressing Siglec-F, namely eosinophils, neutrophils, and alveolar macrophages. We also detect Siglec-F ligand activity in bronchoalveolar lavage fluid fractions containing polymeric secreted mucins, including MUC5B. Consistent with these observations, ligands in the lung increase dramatically during infection with the parasitic nematode, Nippostrongylus brasiliensis, which is known to induce eosinophil accumulation and mucus production. Surprisingly, Gal6S is undetectable in sialylated glycans from eosinophils and BAL fluid analyzed by mass spectrometry. Furthermore, none of the ligands we describe are diminished in mice lacking KSGal6ST and C6ST-1, indicating that neither of the known galactose 6-O-sulfotransferases is required for ligand synthesis. These results establish that ligands for Siglec-F are present on several cell types that are relevant during allergic lung inflammation and argue against the widely held view that Gal6S is critical for glycan recognition by this receptor.
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Affiliation(s)
- Michael L. Patnode
- From the Department of Anatomy and Program in Biomedical Sciences, University of California, San Francisco, California 94143-0452
| | - Chu-Wen Cheng
- the Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Chi-Chi Chou
- the Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Mark S. Singer
- From the Department of Anatomy and Program in Biomedical Sciences, University of California, San Francisco, California 94143-0452
| | - Matilda S. Elin
- From the Department of Anatomy and Program in Biomedical Sciences, University of California, San Francisco, California 94143-0452
| | - Kenji Uchimura
- the Department of Biochemistry, Nagoya University Graduate School of Medicine, Aichi 466-8550, Japan
| | - Paul R. Crocker
- the Division of Cell Signaling and Immunology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom, and
| | - Kay-Hooi Khoo
- the Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Steven D. Rosen
- From the Department of Anatomy and Program in Biomedical Sciences, University of California, San Francisco, California 94143-0452
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Mao H, Kano G, Hudson SA, Brummet M, Zimmermann N, Zhu Z, Bochner BS. Mechanisms of Siglec-F-induced eosinophil apoptosis: a role for caspases but not for SHP-1, Src kinases, NADPH oxidase or reactive oxygen. PLoS One 2013; 8:e68143. [PMID: 23840825 PMCID: PMC3695997 DOI: 10.1371/journal.pone.0068143] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 05/26/2013] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Siglec-F and Siglec-8 are functional paralog proapoptotic cell surface receptors expressed on mouse and human eosinophils, respectively. Whereas Siglec-8 mediated death involves caspases and/or reactive oxygen species (ROS) generation and mitochondrial injury, very little is known about Siglec-F-mediated signaling and apoptosis. Therefore the objective of the current experiments was to better define apoptosis pathways mediated by Siglec-F and Siglec-8. Given that Siglec-F-induced apoptosis is much less robust than Siglec-8-induced apoptosis, we hypothesized that mechanisms involved in cell death via these receptors would differ. METHODS Consequences of engagement of Siglec-F on mouse eosinophils were studied by measuring ROS production, and by performing apoptosis assays using eosinophils from normal, hypereosinophilic, NADPH oxidase-deficient, src homology domain-containing protein tyrosine phosphatase (SHP)-1-deficient, and Lyn kinase-deficient mice. Inhibitors of caspase and Src family kinase activity were also used. RESULTS Engagement of Siglec-F induced mouse eosinophil apoptosis that was modest in magnitude and dependent on caspase activity. There was no detectable ROS generation, or any role for ROS, NADPH oxidase, SHP-1, or Src family kinases in this apoptotic process. CONCLUSIONS These data suggest that Siglec-F-mediated apoptosis is different in both magnitude and mechanisms when compared to published data on Siglec-8-mediated human eosinophil apoptosis. One likely implication of this work is that models targeting Siglec-F in vivo in mice may not provide identical mechanistic predictions for consequences of Siglec-8 targeting in vivo in humans.
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Affiliation(s)
- Hui Mao
- Division of Allergy and Clinical Immunology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Gen Kano
- Division of Allergy and Immunology, Cincinnati Children’s Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Sherry A. Hudson
- Division of Allergy and Clinical Immunology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Mary Brummet
- Division of Allergy and Clinical Immunology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Nives Zimmermann
- Division of Allergy and Immunology, Cincinnati Children’s Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Zhou Zhu
- Division of Allergy and Clinical Immunology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Bruce S. Bochner
- Division of Allergy and Clinical Immunology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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40
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Rosenberg HF, Dyer KD, Foster PS. Eosinophils: changing perspectives in health and disease. Nat Rev Immunol 2012. [PMID: 23154224 DOI: 10.1038/nri334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Eosinophils have been traditionally perceived as terminally differentiated cytotoxic effector cells. Recent studies have profoundly altered this simplistic view of eosinophils and their function. New insights into the molecular pathways that control the development, trafficking and degranulation of eosinophils have improved our understanding of the immunomodulatory functions of these cells and their roles in promoting homeostasis. Likewise, recent developments have generated a more sophisticated view of how eosinophils contribute to the pathogenesis of different diseases, including asthma and primary hypereosinophilic syndromes, and have also provided us with a more complete appreciation of the activities of these cells during parasitic infection.
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Affiliation(s)
- Helene F Rosenberg
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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41
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Abstract
Eosinophils have been traditionally perceived as terminally differentiated cytotoxic effector cells. Recent studies have profoundly altered this simplistic view of eosinophils and their function. New insights into the molecular pathways that control the development, trafficking and degranulation of eosinophils have improved our understanding of the immunomodulatory functions of these cells and their roles in promoting homeostasis. Likewise, recent developments have generated a more sophisticated view of how eosinophils contribute to the pathogenesis of different diseases, including asthma and primary hypereosinophilic syndromes, and have also provided us with a more complete appreciation of the activities of these cells during parasitic infection.
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Kiwamoto T, Kawasaki N, Paulson JC, Bochner BS. Siglec-8 as a drugable target to treat eosinophil and mast cell-associated conditions. Pharmacol Ther 2012; 135:327-36. [PMID: 22749793 PMCID: PMC3587973 DOI: 10.1016/j.pharmthera.2012.06.005] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 06/07/2012] [Indexed: 12/19/2022]
Abstract
Siglecs (sialic acid immunoglobulin-like lectins) are members of the immunoglobulin gene family that contain sialoside binding N-terminal domains. They are cell surface proteins found predominantly on cells of the immune system. Among them, Siglec-8 is uniquely expressed by human eosinophils and mast cells, as well as basophils. Engaging this structure with antibodies or glycan ligands results in apoptosis in human eosinophils and inhibition of release of preformed and newly generated mediators from human mast cells without affecting their survival. Pro-apoptotic effects are also seen when its closest functional paralog, Siglec-F, on mouse eosinophils is similarly engaged in vitro, and beneficial effects are observed after administration of Siglec-F antibody using models of eosinophilic pulmonary and gastrointestinal inflammation in vivo. Siglec-8 targeting may thus provide a means to specifically inhibit or deplete these cell types. Cell-directed therapies are increasingly sought after by the pharmaceutical industry for their potential to reduce side effects and increase safety. The challenge is to identify suitable targets on the cell type of interest, and selectively deliver a therapeutic agent. By targeting Siglec-8, monoclonal antibodies and glycan ligand-conjugated nanoparticles may be ideally suited for treatment of eosinophil and mast cell-related diseases, such as asthma, chronic rhinosinusitis, chronic urticaria, hypereosinophilic syndromes, mast cell and eosinophil malignancies and eosinophilic gastrointestinal disorders.
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Affiliation(s)
- Takumi Kiwamoto
- Department of Medicine, Division of Allergy and Clinical Immunology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224, USA
| | - Norihito Kawasaki
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037 USA
| | - James C. Paulson
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037 USA
| | - Bruce S. Bochner
- Department of Medicine, Division of Allergy and Clinical Immunology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224, USA
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43
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Valent P, Gleich GJ, Reiter A, Roufosse F, Weller PF, Hellmann A, Metzgeroth G, Leiferman KM, Arock M, Sotlar K, Butterfield JH, Cerny-Reiterer S, Mayerhofer M, Vandenberghe P, Haferlach T, Bochner BS, Gotlib J, Horny HP, Simon HU, Klion AD. Pathogenesis and classification of eosinophil disorders: a review of recent developments in the field. Expert Rev Hematol 2012; 5:157-76. [PMID: 22475285 DOI: 10.1586/ehm.11.81] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Eosinophils and their products play an essential role in the pathogenesis of various reactive and neoplastic disorders. Depending on the underlying disease, molecular defect and involved cytokines, hypereosinophilia may develop and may lead to organ damage. In other patients, persistent eosinophilia is accompanied by typical clinical findings, but the causative role and impact of eosinophilia remain uncertain. For patients with eosinophil-mediated organ pathology, early therapeutic intervention with agents reducing eosinophil counts can be effective in limiting or preventing irreversible organ damage. Therefore, it is important to approach eosinophil disorders and related syndromes early by using established criteria, to perform all appropriate staging investigations, and to search for molecular targets of therapy. In this article, we review current concepts in the pathogenesis and evolution of eosinophilia and eosinophil-related organ damage in neoplastic and non-neoplastic conditions. In addition, we discuss classifications of eosinophil disorders and related syndromes as well as diagnostic algorithms and standard treatment for various eosinophil-related disorders.
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Affiliation(s)
- Peter Valent
- Department of Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Vienna, Austria.
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Chen WC, Kawasaki N, Nycholat CM, Han S, Pilotte J, Crocker PR, Paulson JC. Antigen delivery to macrophages using liposomal nanoparticles targeting sialoadhesin/CD169. PLoS One 2012; 7:e39039. [PMID: 22723922 PMCID: PMC3378521 DOI: 10.1371/journal.pone.0039039] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 05/15/2012] [Indexed: 01/15/2023] Open
Abstract
Sialoadhesin (Sn, Siglec-1, CD169) is a member of the sialic acid binding Ig-like lectin (siglec) family expressed on macrophages. Its macrophage specific expression makes it an attractive target for delivering antigens to tissue macrophages via Sn-mediated endocytosis. Here we describe a novel approach for delivering antigens to macrophages using liposomal nanoparticles displaying high affinity glycan ligands of Sn. The Sn-targeted liposomes selectively bind to and are internalized by Sn-expressing cells, and accumulate intracellularly over time. Our results show that ligand decorated liposomes are specific for Sn, since they are taken up by bone marrow derived macrophages that are derived from wild type but not Sn(-/-) mice. Importantly, the Sn-targeted liposomes dramatically enhance the delivery of antigens to macrophages for presentation to and proliferation of antigen-specific T cells. Together, these data provide insights into the potential of cell-specific targeting and delivery of antigens to intracellular organelles of macrophages using Sn-ligand decorated liposomal nanoparticles.
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Affiliation(s)
- Weihsu C. Chen
- Departments of Chemical Physiology and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Norihito Kawasaki
- Departments of Chemical Physiology and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Corwin M. Nycholat
- Departments of Chemical Physiology and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Shoufa Han
- Departments of Chemical Physiology and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Julie Pilotte
- Departments of Chemical Physiology and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Paul R. Crocker
- Wellcome Trust Biocentre, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - James C. Paulson
- Departments of Chemical Physiology and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
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Karlsson NG, McGuckin MA. O-Linked glycome and proteome of high-molecular-mass proteins in human ovarian cancer ascites: Identification of sulfation, disialic acid and O-linked fucose. Glycobiology 2012; 22:918-29. [PMID: 22422444 DOI: 10.1093/glycob/cws060] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The O-linked glycosylation of the main acidic high-molecular-weight glycoprotein from ascites fluid from patients with ovarian cancer were analyzed. The O-linked oligosaccharides were shown to consist of mainly highly sialylated core 1 and 2 structures with a smaller amount of sulfated core 2 structures. These structures were shown to be able to be further extended into small keratan sulfate (KS)-type oligosaccharides with up to four N-acetyllactosamine units. Proteomic studies of the acidic fraction of ascites fluid from patients with ovarian cancer showed that this fraction was enriched in proteoglycans. Among them, lumican, agrin, versican and dystroglycans were potential candidates, with threonine- and serine-rich domains that could carry a significant amount of O-linked glycosylation, including also the O-linked KS. Glycomic analysis using liquid chromatography (LC)-tandem mass spectrometry (MS/MS) also showed that the disialic acid NeuAc-NeuAc- was frequently found as the terminating structure on the O-linked core 1 and 2 oligosaccharides from one ascites sample. Also, a small amount of the epidermal growth factor (EGF)-associated O-linked fucose structure Gal-GlcNAc-Fucitol was detected with and without sialic acid in the LC-MS/MS analysis. Candidate proteins containing O-linked fucose were suggested to be proteoglycan-type molecules containing the O-linked fucose EGF consensus domain.
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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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Farid SS, Mirshafiey A, Razavi A. Siglec-8 and Siglec-F, the new therapeutic targets in asthma. Immunopharmacol Immunotoxicol 2012; 34:721-6. [PMID: 22324980 DOI: 10.3109/08923973.2011.589453] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The recruitment of eosinophils from the circulation into the airway is a prominent feature of allergic asthma. Persistent inflammatory responses may arise from inefficient mechanisms for resolution of inflammation, including delayed apoptosis. Several studies suggest that eosinophil apoptosis is delayed in asthma. Sialic acid-binding immunoglobulin-like lectins are characterized by their sequence similarities and abilities to bind sialic acids in glycoproteins and glycolipids. Siglec-8 is uniquely expressed on eosinophils, mast cells, and basophils. Engagement of Siglec-8 on blood eosinophils results in caspase- and mitochondria-dependent apoptosis. Eosinophil apoptosis is an important therapeutic target for the development of novel anti-asthma treatments that specifically target the eosinophil.
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Affiliation(s)
- Sima Sh Farid
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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48
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Hsu CH, Hung SC, Wu CY, Wong CH. Toward automated oligosaccharide synthesis. Angew Chem Int Ed Engl 2011; 50:11872-923. [PMID: 22127846 DOI: 10.1002/anie.201100125] [Citation(s) in RCA: 205] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Indexed: 12/16/2022]
Abstract
Carbohydrates have been shown to play important roles in biological processes. The pace of development in carbohydrate research is, however, relatively slow due to the problems associated with the complexity of carbohydrate structures and the lack of general synthetic methods and tools available for the study of this class of biomolecules. Recent advances in synthesis have demonstrated that many of these problems can be circumvented. In this Review, we describe the methods developed to tackle the problems of carbohydrate-mediated biological processes, with particular focus on the issue related to the development of the automated synthesis of oligosaccharides. Further applications of carbohydrate microarrays and vaccines to human diseases are also highlighted.
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Affiliation(s)
- Che-Hsiung Hsu
- The Genomics Research Center, Academia Sinica, Taipei, Taiwan
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49
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Hsu CH, Hung SC, Wu CY, Wong CH. Auf dem Weg zur automatisierten Oligosaccharid- Synthese. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201100125] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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50
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Developmental, malignancy-related, and cross-species analysis of eosinophil, mast cell, and basophil siglec-8 expression. J Clin Immunol 2011; 31:1045-53. [PMID: 21938510 DOI: 10.1007/s10875-011-9589-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 09/01/2011] [Indexed: 12/28/2022]
Abstract
OBJECTIVE The aim of this study is to determine when during hematopoiesis Siglec-8 gets expressed, whether it is expressed on hematologic malignancies, and if there are other non-human species that express Siglec-8. METHODS Siglec-8 mRNA and cell surface expression was monitored during in vitro maturation of human eosinophils and mast cells. Flow cytometry was performed on human blood and bone marrow samples, and on blood samples from dogs, baboons, and rhesus and cynomolgus monkeys. RESULTS Siglec-8 is a late maturation marker. It is detectable on eosinophils and basophils from subjects with chronic eosinophilic leukemia, chronic myelogenous leukemia, and on malignant and non-malignant bone marrow mast cells, as well as the HMC-1.2 cell line. None of the Siglec-8 monoclonal antibodies tested recognized leukocytes from dogs, baboons, and rhesus and cynomolgus monkeys. CONCLUSIONS Siglec-8-based therapies should not target immature human leukocytes but should recognize mature and malignant eosinophils, mast cells, and basophils. So far, there is no suitable species for preclinical testing of Siglec-8 monoclonal antibodies.
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