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Lin SY, Schmidt EN, Takahashi-Yamashiro K, Macauley MS. Roles for Siglec-glycan interactions in regulating immune cells. Semin Immunol 2024; 77:101925. [PMID: 39706106 DOI: 10.1016/j.smim.2024.101925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2024] [Revised: 12/08/2024] [Accepted: 12/10/2024] [Indexed: 12/23/2024]
Abstract
Cell surface complex carbohydrates, known as glycans, are positioned to be the first point of contact between two cells. Indeed, interactions between glycans with glycan-binding can modulate cell-cell interactions. This concept is particularly relevant for immune cells, which use an array of glycan-binding proteins to help in the process of differentiating 'self' from 'non-self'. This is exemplified by the sialic acid-binding immunoglobulin-type lectins (Siglecs), which recognize sialic acid. Given that sialic acid is relatively unique to vertebrates, immune cells leverage Siglecs to recognize sialic acid as a marker of 'self'. Siglecs serve many biological roles, with most of these functions regulated through interactions with their sialoglycan ligands. In this review, we provide a comprehensive update on the ligands of Siglecs and how Siglec-sialoglycan interactions help regulate immune cells in the adaptive and innate immune system.
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Affiliation(s)
- Sung-Yao Lin
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - Edward N Schmidt
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | | | - Matthew S Macauley
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada; Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada.
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2
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Zhong X, D’Antona AM, Rouse JC. Mechanistic and Therapeutic Implications of Protein and Lipid Sialylation in Human Diseases. Int J Mol Sci 2024; 25:11962. [PMID: 39596031 PMCID: PMC11594235 DOI: 10.3390/ijms252211962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2024] [Revised: 10/28/2024] [Accepted: 11/05/2024] [Indexed: 11/28/2024] Open
Abstract
Glycan structures of glycoproteins and glycolipids on the surface glycocalyx and luminal sugar layers of intracellular membrane compartments in human cells constitute a key interface between intracellular biological processes and external environments. Sialic acids, a class of alpha-keto acid sugars with a nine-carbon backbone, are frequently found as the terminal residues of these glycoconjugates, forming the critical components of these sugar layers. Changes in the status and content of cellular sialic acids are closely linked to many human diseases such as cancer, cardiovascular, neurological, inflammatory, infectious, and lysosomal storage diseases. The molecular machineries responsible for the biosynthesis of the sialylated glycans, along with their biological interacting partners, are important therapeutic strategies and targets for drug development. The purpose of this article is to comprehensively review the recent literature and provide new scientific insights into the mechanisms and therapeutic implications of sialylation in glycoproteins and glycolipids across various human diseases. Recent advances in the clinical developments of sialic acid-related therapies are also summarized and discussed.
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Affiliation(s)
- Xiaotian Zhong
- BioMedicine Design, Discovery and Early Development, Pfizer Research and Development, 610 Main Street, Cambridge, MA 02139, USA;
| | - Aaron M. D’Antona
- BioMedicine Design, Discovery and Early Development, Pfizer Research and Development, 610 Main Street, Cambridge, MA 02139, USA;
| | - Jason C. Rouse
- Analytical Research and Development, Biotherapeutics Pharmaceutical Sciences, Pfizer Inc., Andover, MA 01810, USA;
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Dong H, Zeng X, Xu J, He C, Sun Z, Liu L, Huang Y, Sun Z, Cao Y, Peng Z, Qiu YA, Yu T. Advances in immune regulation of the G protein-coupled estrogen receptor. Int Immunopharmacol 2024; 136:112369. [PMID: 38824903 DOI: 10.1016/j.intimp.2024.112369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 04/12/2024] [Accepted: 05/27/2024] [Indexed: 06/04/2024]
Abstract
Estrogen and related receptors have been shown to have a significant impact on human development, reproduction, metabolism and immune regulation and to play a critical role in tumor development and treatment. Traditionally, the nuclear estrogen receptors (nERs) ERα and ERβ have been thought to be involved in mediating the estrogenic effects. However, our group and others have previously demonstrated that the G protein-coupled estrogen receptor (GPER) is the third independent ER, and estrogen signaling mediated by GPER is known to play an important role in normal physiology and a variety of abnormal diseases. Interestingly, recent studies have progressively revealed GPER involvement in the maintenance of the normal immune system, abnormal immune diseases, and inflammatory lesions, which may be of significant clinical value primarily in the immunotherapy of tumors. In this article, we review current advances in GPER-related immunomodulators and provide a theoretical basis and potential clinical targets to ameliorate immune-related diseases and immunotherapy for tumors.
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Affiliation(s)
- Hanzhi Dong
- Department of Oncology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330000, China
| | - Xiaoqiang Zeng
- Jiangxi Medical College, Nanchang University, Nanchang 330000, China
| | - Jiawei Xu
- Department of Breast Surgery, Jiangxi Cancer Hospital, The Second Affiliated Hospital of Nanchang Medical College, Jiangxi Clinical Research Center for Cancer, Nanchang 330029, China
| | - Chongwu He
- Department of Breast Surgery, Jiangxi Cancer Hospital, The Second Affiliated Hospital of Nanchang Medical College, Jiangxi Clinical Research Center for Cancer, Nanchang 330029, China
| | - Zhengkui Sun
- Department of Breast Surgery, Jiangxi Cancer Hospital, The Second Affiliated Hospital of Nanchang Medical College, Jiangxi Clinical Research Center for Cancer, Nanchang 330029, China
| | - Liyan Liu
- Department of Pharmacy, Jiangxi Cancer Hospital, The Second Affiliated Hospital of Nanchang Medical College, Jiangxi Clinical Research Center for Cancer, Nanchang 330029, China
| | - Yanxiao Huang
- Jiangxi Medical College, Nanchang University, Nanchang 330000, China
| | - Zhe Sun
- Department of Oncology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330000, China
| | - Yuan Cao
- Department of Oncology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330000, China
| | - Zhiqiang Peng
- Department of Lymphohematology, Jiangxi Cancer Hospital, The Second Affiliated Hospital of Nanchang Medical College, Jiangxi Clinical Research Center for Cancer, Nanchang 330029, China.
| | - Yu-An Qiu
- Department of Critical Care Medicine, Jiangxi Cancer Hospital, The Second Affiliated Hospital of Nanchang Medical College, Jiangxi Clinical Research Center for Cancer, Nanchang 330029, China.
| | - Tenghua Yu
- Department of Breast Surgery, Jiangxi Cancer Hospital, The Second Affiliated Hospital of Nanchang Medical College, Jiangxi Clinical Research Center for Cancer, Nanchang 330029, China.
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Korver W, Benet Z, Wong A, Negri GL, Chang K, Sanchez R, Leung J, De Freitas N, Luu T, Schanin J, Youngblood BA. Regulation of mast cells by overlapping but distinct protein interactions of Siglec-6 and Siglec-8. Allergy 2024; 79:629-642. [PMID: 38186079 DOI: 10.1111/all.16004] [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: 09/28/2023] [Revised: 11/13/2023] [Accepted: 12/12/2023] [Indexed: 01/09/2024]
Abstract
BACKGROUND Sialic acid-binding immunoglobulin-like lectin (Siglec)-6 and Siglec-8 are closely related mast cell (MC) receptors with broad inhibitory activity, but whose functional differences are incompletely understood. METHODS Proteomic profiling using quantitative mass spectrometry was performed on primary mouse MCs to identify proteins associated with Siglec-6 and Siglec-8. For functional characterization, each receptor was evaluated biochemically and in ex vivo and in vivo inhibition models of IgE and non-IgE-mediated MC activation in Siglec-6- or Siglec-8-expressing transgenic mice. RESULTS Siglec-6 and Siglec-8 were found in MCs within large complexes, interacting with 66 and 86 proteins, respectively. Strikingly, Siglec-6 and Siglec-8 interacted with a large cluster of proteins involved in IgE and non-IgE-mediated MC activation, including the high affinity IgE receptor, stem cell factor (SCF) receptor KIT/CD117, IL-4 and IL-33 receptors, and intracellular kinases LYN and JAK1. Protein interaction networks revealed Siglec-6 and Siglec-8 had overlapping yet distinct MC functions, with a potentially broader regulatory role for Siglec-6. Indeed, Siglec-6 preferentially interacted with the mature form of KIT at the cell surface, and treatment with an anti-Siglec-6 antibody significantly inhibited SCF-mediated MC activation more in comparison to targeting Siglec-8. CONCLUSION These data demonstrate a central role for Siglec-6 and Siglec-8 in controlling MC activation through interactions with multiple activating receptors and key signaling molecules. Our findings suggest that Siglec-6 has a role distinct from that of Siglec-8 in regulating MC function and represents a distinct potential therapeutic target in mast cell-driven diseases.
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Affiliation(s)
| | | | - Alan Wong
- Allakos Inc., San Carlos, California, USA
| | - Gian Luca Negri
- LM Biostat Consulting Inc., Victoria, British Columbia, Canada
| | | | | | - John Leung
- Allakos Inc., San Carlos, California, USA
| | | | - Thuy Luu
- Allakos Inc., San Carlos, California, USA
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Metz M, Kolkhir P, Altrichter S, Siebenhaar F, Levi-Schaffer F, Youngblood BA, Church MK, Maurer M. Mast cell silencing: A novel therapeutic approach for urticaria and other mast cell-mediated diseases. Allergy 2024; 79:37-51. [PMID: 37605867 DOI: 10.1111/all.15850] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/21/2023] [Accepted: 07/29/2023] [Indexed: 08/23/2023]
Abstract
Chronic urticaria (CU) is a mast cell (MC)-dependent disease with limited therapeutic options. Current management strategies are directed at inhibiting IgE-mediated activation of MCs and antagonizing effects of released mediators. Due to the complexity and heterogeneity of CU and other MC diseases and mechanisms of MC activation-including multiple activating receptors and ligands, diverse signaling pathways, and a menagerie of mediators-strategies of MC depletion or MC silencing (i.e., inhibition of MC activation via binding of inhibitory receptors) have been developed to overcome limitations of singularly targeted agents. MC silencers, such as agonist monoclonal antibodies that engage inhibitory receptors (e.g., sialic acid-binding immunoglobulin-like lectin8 -[Siglec-8] [lirentelimab/AK002], Siglec-6 [AK006], and CD200R [LY3454738]), have reached preclinical and clinical stages of development. In this review, we (1) describe the role of MCs in the pathogenesis of CU, highlighting similarities with other MC diseases in disease mechanisms and response to treatment; (2) explore current therapeutic strategies, categorized by nonspecific immunosuppression, targeted inhibition of MC activation or mediators, and targeted modulation of MC activity; and (3) introduce the concept of MC silencing as an emerging strategy that could selectively block activation of MCs without eliciting or exacerbating on- or off-target, immunosuppressive adverse effects.
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Affiliation(s)
- Martin Metz
- Institute of Allergology, Charité-Universitätsmedizin Berlin (corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin), Berlin, Germany
- Berlin Institute of Health, Berlin, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Immunology and Allergology IA, Berlin, Germany
| | - Pavel Kolkhir
- Institute of Allergology, Charité-Universitätsmedizin Berlin (corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin), Berlin, Germany
- Berlin Institute of Health, Berlin, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Immunology and Allergology IA, Berlin, Germany
| | - Sabine Altrichter
- Institute of Allergology, Charité-Universitätsmedizin Berlin (corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin), Berlin, Germany
- Berlin Institute of Health, Berlin, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Immunology and Allergology IA, Berlin, Germany
- Department of Dermatology and Venerology, Kepler University Hospital, Linz, Austria
| | - Frank Siebenhaar
- Institute of Allergology, Charité-Universitätsmedizin Berlin (corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin), Berlin, Germany
- Berlin Institute of Health, Berlin, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Immunology and Allergology IA, Berlin, Germany
| | - Francesca Levi-Schaffer
- Pharmacology and Experimental Therapeutics Unit, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | | | - Martin K Church
- Institute of Allergology, Charité-Universitätsmedizin Berlin (corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin), Berlin, Germany
- Berlin Institute of Health, Berlin, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Immunology and Allergology IA, Berlin, Germany
| | - Marcus Maurer
- Institute of Allergology, Charité-Universitätsmedizin Berlin (corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin), Berlin, Germany
- Berlin Institute of Health, Berlin, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Immunology and Allergology IA, Berlin, Germany
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Siebenhaar F, Altrichter S, Bonnekoh H, Hawro T, Hawro M, Michaelis EG, Kantor AM, Chang AT, Youngblood BA, Singh B, Rasmussen HS, Maurer M. Safety and efficacy of lirentelimab in patients with refractory indolent systemic mastocytosis: a first-in-human clinical trial. Br J Dermatol 2023; 189:511-519. [PMID: 37290787 DOI: 10.1093/bjd/ljad191] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 05/12/2023] [Accepted: 06/02/2023] [Indexed: 06/10/2023]
Abstract
BACKGROUND Indolent systemic mastocytosis (ISM) is characterized by excessive mast cell (MC) accumulation and MC-driven signs and symptoms. Currently used therapies are not approved and have limited efficacy. Lirentelimab (AK002) is a monoclonal antibody against sialic acid-binding immunoglobulin-like lectin (Siglec)-8 that inhibits MC activation. OBJECTIVES To determine the safety, tolerability and efficacy of lirentelimab in reducing the symptoms of ISM. METHODS At a specialty centre for mastocytosis in Germany, we conducted a phase I first-in-human single-ascending and multidose clinical trial of lirentelimab in patients with ISM. Eligible adults had World Health Organization-confirmed ISM and an unsatisfactory response to available treatment. In part A, patients received a single dose of lirentelimab 0.0003, 0.001, 0.003, 0.01 or 0.03 mg kg-1; in part B, patients received one lirentelimab dose of 0.3 mg kg-1 or 1.0 mg kg-1; and in part C, patients received either 1.0 mg kg-1 lirentelimab every 4 weeks for 6 months or ascending doses of lirentelimab (one dose of 1 mg kg-1 followed by five doses of 3-10 mg kg-1 every 4 weeks). The primary endpoint was safety/tolerability. Secondary endpoints included changes from baseline in Mastocytosis Symptom Questionnaire (MSQ), Mastocytosis Activity Score (MAS) and Mastocytosis Quality of Life Questionnaire (MC-QoL) scores at 2 weeks after the final dose. RESULTS In 25 patients with ISM (13 in parts A + B and 12 in part C; median age 51 years, 76% female, median 4.6 years from diagnosis), the most common treatment-related adverse events (AEs) were feeling hot (76%) and experiencing a headache (48%). No serious AEs occurred. Median MSQ and MAS symptom severity scores in part C improved (vs. baseline) across all symptoms [MSQ: skin (38-56%), gastrointestinal (49-60%), neurological (47-59%), musculoskeletal (26-27%); MAS: skin (53-59%), gastrointestinal (72-85%), neurological (20-57%), musculoskeletal (25%)]. Median MC-QoL scores improved across all domains: symptoms (39%), social life/functioning (42%), emotions (57%) and skin (44%). CONCLUSIONS Lirentelimab was generally well tolerated and improved symptoms and quality of life in patients with ISM. The therapeutic potential of lirentelimab should be considered for ISM.
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Affiliation(s)
- Frank Siebenhaar
- Institute of Allergology
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Immunology and Allergology IA, Berlin, Germany
| | - Sabine Altrichter
- Institute of Allergology
- Department of Dermatology and Venerology, Kepler University Hospital, Linz, Austria
| | - Hanna Bonnekoh
- Institute of Allergology
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Immunology and Allergology IA, Berlin, Germany
| | | | | | - Edward G Michaelis
- Institute of Allergology
- Institute of Pathology, Charité-Universitätsmedizin Berlin, Berlin, Germany (corporate member or Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany, and Berlin Institute of Health, Berlin, Germany)
| | | | | | | | | | | | - Marcus Maurer
- Institute of Allergology
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Immunology and Allergology IA, Berlin, Germany
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Miralda I, Samanas NB, Seo AJ, Foronda JS, Sachen J, Hui Y, Morrison SD, Oskeritzian CA, Piliponsky AM. Siglec-9 is an inhibitory receptor on human mast cells in vitro. J Allergy Clin Immunol 2023; 152:711-724.e14. [PMID: 37100120 PMCID: PMC10524464 DOI: 10.1016/j.jaci.2023.04.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 04/04/2023] [Accepted: 04/13/2023] [Indexed: 04/28/2023]
Abstract
BACKGROUND Mast cell activation is critical for the development of allergic diseases. Ligation of sialic acid-binding immunoglobin-like lectins (Siglecs), such as Siglec-6, -7, and -8 as well as CD33, have been shown to inhibit mast cell activation. Recent studies showed that human mast cells express Siglec-9, an inhibitory receptor also expressed by neutrophils, monocytes, macrophages, and dendritic cells. OBJECTIVE We aimed to characterize Siglec-9 expression and function in human mast cells in vitro. METHODS We assessed the expression of Siglec-9 and Siglec-9 ligands on human mast cell lines and human primary mast cells by real-time quantitative PCR, flow cytometry, and confocal microscopy. We used a clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) gene editing approach to disrupt the SIGLEC9 gene. We evaluated Siglec-9 inhibitory activity on mast cell function by using native Siglec-9 ligands, glycophorin A (GlycA), and high-molecular-weight hyaluronic acid, a monoclonal antibody against Siglec-9, and coengagement of Siglec-9 with the high-affinity receptor for IgE (FcεRI). RESULTS Human mast cells express Siglec-9 and Siglec-9 ligands. SIGLEC9 gene disruption resulted in increased expression of activation markers at baseline and increased responsiveness to IgE-dependent and IgE-independent stimulation. Pretreatment with GlycA or high-molecular-weight hyaluronic acid followed by IgE-dependent or -independent stimulation had an inhibitory effect on mast cell degranulation. Coengagement of Siglec-9 with FcεRI in human mast cells resulted in reduced degranulation, arachidonic acid production, and chemokine release. CONCLUSIONS Siglec-9 and its ligands play an important role in limiting human mast cell activation in vitro.
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Affiliation(s)
- Irina Miralda
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, Wash
| | - Nyssa B Samanas
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, Wash
| | - Albert J Seo
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, Wash
| | - Jake S Foronda
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, Wash
| | - Josie Sachen
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, Wash
| | - Yvonne Hui
- University of South Carolina School of Medicine, Columbia, SC
| | - Shane D Morrison
- Department of Surgery, Division of Plastic Surgery, Seattle Children's Hospital, Seattle, Wash
| | | | - Adrian M Piliponsky
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, Wash; Department of Pediatrics, University of Washington School of Medicine, Seattle, Wash; Department of Pathology, University of Washington School of Medicine, Seattle, Wash; Department of Global Health, University of Washington School of Medicine, Seattle, Wash.
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Theoharides TC, Kempuraj D. Potential Role of Moesin in Regulating Mast Cell Secretion. Int J Mol Sci 2023; 24:12081. [PMID: 37569454 PMCID: PMC10418457 DOI: 10.3390/ijms241512081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/20/2023] [Accepted: 07/24/2023] [Indexed: 08/13/2023] Open
Abstract
Mast cells have existed for millions of years in species that never suffer from allergic reactions. Hence, in addition to allergies, mast cells can play a critical role in homeostasis and inflammation via secretion of numerous vasoactive, pro-inflammatory and neuro-sensitizing mediators. Secretion may utilize different modes that involve the cytoskeleton, but our understanding of the molecular mechanisms regulating secretion is still not well understood. The Ezrin/Radixin/Moesin (ERM) family of proteins is involved in linking cell surface-initiated signaling to the actin cytoskeleton. However, how ERMs may regulate secretion from mast cells is still poorly understood. ERMs contain two functional domains connected through a long α-helix region, the N-terminal FERM (band 4.1 protein-ERM) domain and the C-terminal ERM association domain (C-ERMAD). The FERM domain and the C-ERMAD can bind to each other in a head-to-tail manner, leading to a closed/inactive conformation. Typically, phosphorylation on the C-terminus Thr has been associated with the activation of ERMs, including secretion from macrophages and platelets. It has previously been shown that the ability of the so-called mast cell "stabilizer" disodium cromoglycate (cromolyn) to inhibit secretion from rat mast cells closely paralleled the phosphorylation of a 78 kDa protein, which was subsequently shown to be moesin, a member of ERMs. Interestingly, the phosphorylation of moesin during the inhibition of mast cell secretion was on the N-terminal Ser56/74 and Thr66 residues. This phosphorylation pattern could lock moesin in its inactive state and render it inaccessible to binding to the Soluble NSF attachment protein receptors (SNAREs) and synaptosomal-associated proteins (SNAPs) critical for exocytosis. Using confocal microscopic imaging, we showed moesin was found to colocalize with actin and cluster around secretory granules during inhibition of secretion. In conclusion, the phosphorylation pattern and localization of moesin may be important in the regulation of mast cell secretion and could be targeted for the development of effective inhibitors of secretion of allergic and inflammatory mediators from mast cells.
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Affiliation(s)
- Theoharis C. Theoharides
- Institute for Neuro-Immune Medicine, Dr. Kiran C. Patel College of Osteopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL 33328, USA;
- Laboratory of Molecular Immunopharmacology and Drug Discovery, Department of Immunology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Duraisamy Kempuraj
- Institute for Neuro-Immune Medicine, Dr. Kiran C. Patel College of Osteopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL 33328, USA;
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Thames AH, Moons SJ, Wong DA, Boltje TJ, Bochner BS, Jewett MC. GlycoCAP: A Cell-Free, Bacterial Glycosylation Platform for Building Clickable Azido-Sialoglycoproteins. ACS Synth Biol 2023; 12:1264-1274. [PMID: 37040463 PMCID: PMC10758250 DOI: 10.1021/acssynbio.3c00017] [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] [Indexed: 04/13/2023]
Abstract
Glycan-binding receptors known as lectins represent a class of potential therapeutic targets. Yet, the therapeutic potential of targeting lectins remains largely untapped due in part to limitations in tools for building glycan-based drugs. One group of desirable structures is proteins with noncanonical glycans. Cell-free protein synthesis systems have matured as a promising approach for making glycoproteins that may overcome current limitations and enable new glycoprotein medicines. Yet, this approach has not been applied to the construction of proteins with noncanonical glycans. To address this limitation, we develop a cell-free glycoprotein synthesis platform for building noncanonical glycans and, specifically, clickable azido-sialoglycoproteins (called GlycoCAP). The GlycoCAP platform uses an Escherichia coli-based cell-free protein synthesis system for the site-specific installation of noncanonical glycans onto proteins with a high degree of homogeneity and efficiency. As a model, we construct four noncanonical glycans onto a dust mite allergen (Der p 2): α2,3 C5-azido-sialyllactose, α2,3 C9-azido-sialyllactose, α2,6 C5-azido-sialyllactose, and α2,6 C9-azido-sialyllactose. Through a series of optimizations, we achieve more than 60% sialylation efficiency with a noncanonical azido-sialic acid. We then show that the azide click handle can be conjugated with a model fluorophore using both strain-promoted and copper-catalyzed click chemistry. We anticipate that GlycoCAP will facilitate the development and discovery of glycan-based drugs by granting access to a wider variety of possible noncanonical glycan structures and also provide an approach for functionalizing glycoproteins by click chemistry conjugation.
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Affiliation(s)
- Ariel Helms Thames
- Medical Scientist Training Program, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, United States
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Tech B486, Evanston, Illinois 60208, United States
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, Illinois 60208, United States
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, United States
| | - Sam J Moons
- Synvenio B.V., Mercator 3, Nijmegen 6525ED, The Netherlands
| | - Derek A Wong
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Tech B486, Evanston, Illinois 60208, United States
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd, Evanston, Illinois 60208, United States
| | - Thomas J Boltje
- Institute for Molecules and Materials, Radboud University Nijmegen, Nijmegen 6525AJ, The Netherlands
| | - Bruce S Bochner
- Medical Scientist Training Program, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, United States
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, United States
| | - Michael C Jewett
- Medical Scientist Training Program, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, United States
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Road, Tech B486, Evanston, Illinois 60208, United States
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, Illinois 60208, United States
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd, Evanston, Illinois 60208, United States
- Simpson Querrey Institute, Northwestern University, Chicago, Illinois 60611, United States
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10
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Siddiqui SS. Siglecs in health and disease. Mol Aspects Med 2023; 90:101147. [PMID: 36243585 DOI: 10.1016/j.mam.2022.101147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Shoib Sarwar Siddiqui
- School of Life and Medical Sciences, University of Hertfordshire, College Lane Campus, Hatfield, AL10 9AB, United Kingdom.
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Angata T, Varki A. Discovery, classification, evolution and diversity of Siglecs. Mol Aspects Med 2023; 90:101117. [PMID: 35989204 PMCID: PMC9905256 DOI: 10.1016/j.mam.2022.101117] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 08/03/2022] [Accepted: 08/06/2022] [Indexed: 02/08/2023]
Abstract
Immunoglobulin (Ig) superfamily proteins play diverse roles in vertebrates, including regulation of cellular responses by sensing endogenous or exogenous ligands. Siglecs are a family of glycan-recognizing proteins belonging to the Ig superfamily (i.e., I-type lectins). Siglecs are expressed on various leukocyte types and are involved in diverse aspects of immunity, including the regulation of inflammatory responses, leukocyte proliferation, host-microbe interaction, and cancer immunity. Sialoadhesin/Siglec-1, CD22/Siglec-2, and myelin-associated glycoprotein/Siglec-4 were among the first to be characterized as members of the Siglec family, and along with Siglec-15, they are relatively well-conserved among tetrapods. Conversely, CD33/Siglec-3-related Siglecs (CD33rSiglecs, so named as they show high sequence similarity with CD33/Siglec-3) are encoded in a gene cluster with many interspecies variations and even intraspecies variations within some lineages such as humans. The rapid evolution of CD33rSiglecs expressed on leukocytes involved in innate immunity likely reflects the selective pressure by pathogens that interact and possibly exploit these Siglecs. Human Siglecs have several additional unique and/or polymorphic properties as compared with closely related great apes, changes possibly related to the loss of the sialic acid Neu5Gc, another distinctly human event in sialobiology. Multiple changes in human CD33rSiglecs compared to great apes include many examples of human-specific expression in non-immune cells, coinciding with human-specific diseases involving such cell types. Some Siglec gene polymorphisms have dual consequences-beneficial in a situation but detrimental in another. The association of human Siglec gene polymorphisms with several infectious and non-infectious diseases likely reflects the ongoing competition between the host and microbial pathogens.
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Affiliation(s)
- Takashi Angata
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan.
| | - Ajit Varki
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA.
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Siew JJ, Chern Y, Khoo KH, Angata T. Roles of Siglecs in neurodegenerative diseases. Mol Aspects Med 2023; 90:101141. [PMID: 36089405 DOI: 10.1016/j.mam.2022.101141] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/16/2022] [Accepted: 08/29/2022] [Indexed: 02/08/2023]
Abstract
Microglia are resident myeloid cells in the central nervous system (CNS) with a unique developmental origin, playing essential roles in developing and maintaining the CNS environment. Recent studies have revealed the involvement of microglia in neurodegenerative diseases, such as Alzheimer's disease, through the modulation of neuroinflammation. Several members of the Siglec family of sialic acid recognition proteins are expressed on microglia. Since the discovery of the genetic association between a polymorphism in the CD33 gene and late-onset Alzheimer's disease, significant efforts have been made to elucidate the molecular mechanism underlying the association between the polymorphism and Alzheimer's disease. Furthermore, recent studies have revealed additional potential associations between Siglecs and Alzheimer's disease, implying that the reduced signal from inhibitory Siglec may have an overall protective effect in lowering the disease risk. Evidences suggesting the involvement of Siglecs in other neurodegenerative diseases are also emerging. These findings could help us predict the roles of Siglecs in other neurodegenerative diseases. However, little is known about the functionally relevant Siglec ligands in the brain, which represents a new frontier. Understanding how microglial Siglecs and their ligands in CNS contribute to the regulation of CNS homeostasis and pathogenesis of neurodegenerative diseases may provide us with a new avenue for disease prevention and intervention.
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Affiliation(s)
- Jian Jing Siew
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yijuang Chern
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Kay-Hooi Khoo
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Takashi Angata
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan.
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