1
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Kizuka Y. Regulation of intracellular activity of N-glycan branching enzymes in mammals. J Biol Chem 2024; 300:107471. [PMID: 38879010 DOI: 10.1016/j.jbc.2024.107471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 06/01/2024] [Accepted: 06/06/2024] [Indexed: 07/07/2024] Open
Abstract
Most proteins in the secretory pathway are glycosylated, and N-glycans are estimated to be attached to over 7000 proteins in humans. As structural variation of N-glycans critically regulates the functions of a particular glycoprotein, it is pivotal to understand how structural diversity of N-glycans is generated in cells. One of the major factors conferring structural variation of N-glycans is the variable number of N-acetylglucosamine branches. These branch structures are biosynthesized by dedicated glycosyltransferases, including GnT-III (MGAT3), GnT-IVa (MGAT4A), GnT-IVb (MGAT4B), GnT-V (MGAT5), and GnT-IX (GnT-Vb, MGAT5B). In addition, the presence or absence of core modification of N-glycans, namely, core fucose (included as an N-glycan branch in this manuscript), synthesized by FUT8, also confers large structural variation on N-glycans, thereby crucially regulating many protein-protein interactions. Numerous biochemical and medical studies have revealed that these branch structures are involved in a wide range of physiological and pathological processes. However, the mechanisms regulating the activity of the biosynthetic glycosyltransferases are yet to be fully elucidated. In this review, we summarize the previous findings and recent updates regarding regulation of the activity of these N-glycan branching enzymes. We hope that such information will help readers to develop a comprehensive overview of the complex system regulating mammalian N-glycan maturation.
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Affiliation(s)
- Yasuhiko Kizuka
- Institute for Glyco-core Research (iGCORE), Gifu University, Gifu, Japan.
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2
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Zhao K, Wu C, Li X, Niu M, Wu D, Cui X, Zhao H. From mechanism to therapy: the journey of CD24 in cancer. Front Immunol 2024; 15:1401528. [PMID: 38881902 PMCID: PMC11176514 DOI: 10.3389/fimmu.2024.1401528] [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: 03/15/2024] [Accepted: 04/25/2024] [Indexed: 06/18/2024] Open
Abstract
CD24 is a glycosylphosphatidylinositol-anchored protein that is expressed in a wide range of tissues and cell types. It is involved in a variety of physiological and pathological processes, including cell adhesion, migration, differentiation, and apoptosis. Additionally, CD24 has been studied extensively in the context of cancer, where it has been found to play a role in tumor growth, invasion, and metastasis. In recent years, there has been growing interest in CD24 as a potential therapeutic target for cancer treatment. This review summarizes the current knowledge of CD24, including its structure, function, and its role in cancer. Finally, we provide insights into potential clinical application of CD24 and discuss possible approaches for the development of targeted cancer therapies.
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Affiliation(s)
- Kai Zhao
- Department of Neurosurgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Caifeng Wu
- Department of Hand and Foot, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiangjun Li
- Department of Breast Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Mengchao Niu
- Department of Operation Room, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Dan Wu
- Department of Neurosurgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiaofeng Cui
- Department of Neurosurgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Hai Zhao
- Department of Neurosurgery, The Affiliated Hospital of Qingdao University, Qingdao, China
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3
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Koff M, Monagas-Valentin P, Novikov B, Chandel I, Panin V. Protein O-mannosylation: one sugar, several pathways, many functions. Glycobiology 2023; 33:911-926. [PMID: 37565810 PMCID: PMC10859634 DOI: 10.1093/glycob/cwad067] [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: 07/16/2023] [Revised: 07/23/2023] [Accepted: 07/31/2023] [Indexed: 08/12/2023] Open
Abstract
Recent research has unveiled numerous important functions of protein glycosylation in development, homeostasis, and diseases. A type of glycosylation taking the center stage is protein O-mannosylation, a posttranslational modification conserved in a wide range of organisms, from yeast to humans. In animals, protein O-mannosylation plays a crucial role in the nervous system, whereas protein O-mannosylation defects cause severe neurological abnormalities and congenital muscular dystrophies. However, the molecular and cellular mechanisms underlying protein O-mannosylation functions and biosynthesis remain not well understood. This review outlines recent studies on protein O-mannosylation while focusing on the functions in the nervous system, summarizes the current knowledge about protein O-mannosylation biosynthesis, and discusses the pathologies associated with protein O-mannosylation defects. The evolutionary perspective revealed by studies in the Drosophila model system are also highlighted. Finally, the review touches upon important knowledge gaps in the field and discusses critical questions for future research on the molecular and cellular mechanisms associated with protein O-mannosylation functions.
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Affiliation(s)
- Melissa Koff
- Department of Biochemistry and Biophysics, AgriLife Research, Texas A&M University, College Station, College Station, TX 77843, United States
| | - Pedro Monagas-Valentin
- Department of Biochemistry and Biophysics, AgriLife Research, Texas A&M University, College Station, College Station, TX 77843, United States
| | - Boris Novikov
- Department of Biochemistry and Biophysics, AgriLife Research, Texas A&M University, College Station, College Station, TX 77843, United States
| | - Ishita Chandel
- Department of Biochemistry and Biophysics, AgriLife Research, Texas A&M University, College Station, College Station, TX 77843, United States
| | - Vladislav Panin
- Department of Biochemistry and Biophysics, AgriLife Research, Texas A&M University, College Station, College Station, TX 77843, United States
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4
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Hours CM, Gil S, Gressens P. Molecular and Cellular Insights: A Focus on Glycans and the HNK1 Epitope in Autism Spectrum Disorder. Int J Mol Sci 2023; 24:15139. [PMID: 37894820 PMCID: PMC10606426 DOI: 10.3390/ijms242015139] [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: 08/16/2023] [Revised: 10/08/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023] Open
Abstract
Autism Spectrum Disorder (ASD) is a synaptic disorder with a GABA/glutamate imbalance in the perineuronal nets and structural abnormalities such as increased dendritic spines and decreased long distance connections. Specific pregnancy disorders significantly increase the risk for an ASD phenotype such as preeclampsia, preterm birth, hypoxia phenomena, and spontaneous miscarriages. They are associated with defects in the glycosylation-immune placental processes implicated in neurogenesis. Some glycans epitopes expressed in the placenta, and specifically in the extra-villous trophoblast also have predominant functions in dendritic process and synapse function. Among these, the most important are CD57 or HNK1, CD22, CD24, CD33 and CD45. They modulate the innate immune cells at the maternal-fetal interface and they promote foeto-maternal tolerance. There are many glycan-based pathways of immunosuppression. N-glycosylation pathway dysregulation has been found to be associated with autoimmune-like phenotypes and maternal-autoantibody-related (MAR) autism have been found to be associated with central, systemic and peripheric autoimmune processes. Essential molecular pathways associated with the glycan-epitopes expression have been found to be specifically dysregulated in ASD, notably the Slit/Robo, Wnt, and mTOR/RAGE signaling pathways. These modifications have important effects on major transcriptional pathways with important genetic expression consequences. These modifications lead to defects in neuronal progenitors and in the nervous system's implementation specifically, with further molecular defects in the GABA/glutamate system. Glycosylation placental processes are crucial effectors for proper maternofetal immunity and endocrine/paracrine pathways formation. Glycans/ galectins expression regulate immunity and neurulation processes with a direct link with gene expression. These need to be clearly elucidated in ASD pathophysiology.
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Affiliation(s)
- Camille M Hours
- INSERM 1141, NeuroDiderot, Neuroprotection of the Developing Brain, Université Paris Cité, 75019 Paris, France
- Service de Psychiatrie de l'Enfant et de l'Adolescent, APHP, Hôpital Robert Debré, 75019 Paris, France
| | - Sophie Gil
- INSERM 1144, Therapeutics in Neuropsychopharmacology, Université Paris Cité, 75019 Paris, France
| | - Pierre Gressens
- INSERM 1141, NeuroDiderot, Neuroprotection of the Developing Brain, Université Paris Cité, 75019 Paris, France
- Neurologie Pédiatrique, APHP, Hôpital Robert Debré, 75019 Paris, France
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5
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Costa J, Hayes C, Lisacek F. Protein glycosylation and glycoinformatics for novel biomarker discovery in neurodegenerative diseases. Ageing Res Rev 2023; 89:101991. [PMID: 37348818 DOI: 10.1016/j.arr.2023.101991] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/25/2023] [Accepted: 06/18/2023] [Indexed: 06/24/2023]
Abstract
Glycosylation is a common post-translational modification of brain proteins including cell surface adhesion molecules, synaptic proteins, receptors and channels, as well as intracellular proteins, with implications in brain development and functions. Using advanced state-of-the-art glycomics and glycoproteomics technologies in conjunction with glycoinformatics resources, characteristic glycosylation profiles in brain tissues are increasingly reported in the literature and growing evidence shows deregulation of glycosylation in central nervous system disorders, including aging associated neurodegenerative diseases. Glycan signatures characteristic of brain tissue are also frequently described in cerebrospinal fluid due to its enrichment in brain-derived molecules. A detailed structural analysis of brain and cerebrospinal fluid glycans collected in publications in healthy and neurodegenerative conditions was undertaken and data was compiled to create a browsable dedicated set in the GlyConnect database of glycoproteins (https://glyconnect.expasy.org/brain). The shared molecular composition of cerebrospinal fluid with brain enhances the likelihood of novel glycobiomarker discovery for neurodegeneration, which may aid in unveiling disease mechanisms, therefore, providing with novel therapeutic targets as well as diagnostic and progression monitoring tools.
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Affiliation(s)
- Júlia Costa
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal.
| | - Catherine Hayes
- Proteome Informatics Group, Swiss Institute of Bioinformatics, CH-1227 Geneva, Switzerland
| | - Frédérique Lisacek
- Proteome Informatics Group, Swiss Institute of Bioinformatics, CH-1227 Geneva, Switzerland; Computer Science Department, University of Geneva, CH-1227 Geneva, Switzerland; Section of Biology, University of Geneva, CH-1211 Geneva, Switzerland
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6
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Li X, Wilmanowski R, Gao X, VanAernum ZL, Donnelly DP, Kochert B, Schuessler HA, Richardson D. Precise O-Glycosylation Site Localization of CD24Fc by LC-MS Workflows. Anal Chem 2022; 94:8416-8425. [PMID: 35622908 DOI: 10.1021/acs.analchem.2c01137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
CD24Fc is a homodimeric recombinant Fc-fusion protein comprised of human CD24 connected to immunoglobulin G1 (IgG1) Fc fragment. CD24 is heavily glycosylated, and its biological function is considered mainly mediated by its glycosylation. Identification of the O-glycosylation sites would facilitate an in-depth understanding of the functional role of O-glycans in CD24. However, the presence of clustered mucin-type O-glycans together with N-glycans makes the determination of O-glycosylation sites and abundance very challenging. In this study, two sets of liquid chromatography-mass spectrometry (LC-MS) workflows were developed for the comprehensive characterization of O-glycosylation in CD24: (1) Fractionation and collision-induced dissociation (CID) workflow involving multienzyme digestion, fractionation, OpeRATOR/SialEXO digestion, and CID analysis; (2) Direct OpeRATOR/SialEXO digestion followed by electron-transfer/higher-energy collision dissociation (EThcD) analysis. The precise O-glycosylation sites were identified in CD24 for the first time, and the site occupancy was assessed. A total of 12 O-glycosylation sites were identified. Seven glycosylation sites were identified by both workflows, and five additional sites were identified only by the EThcD workflow. The predominant O-glycosylation site in CD24 was Thr25 followed by Thr15. The CID workflow provided an overall relative quantitation of O-glycoforms at the CD24 level and site localization for singly O-glycosylated peptides. The EThcD workflow directly identified glycosylation sites by tandem mass spectrometry (MS/MS) for singly, doubly, and triply O-glycosylated peptides. Together, both workflows validated each other's results and can be applied to a complex mucin-type O-glycosylation site analysis of other glycoproteins and Fc-fusion therapeutics.
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Affiliation(s)
- Xiaojuan Li
- Analytical Research & Development Mass Spectrometry, MRL, Merck & Co., Inc., Kenilworth 07033, New Jersey, United States
| | | | - Xinliu Gao
- Analytical Research & Development Mass Spectrometry, MRL, Merck & Co., Inc., Kenilworth 07033, New Jersey, United States
| | - Zachary L VanAernum
- Analytical Research & Development Mass Spectrometry, MRL, Merck & Co., Inc., Kenilworth 07033, New Jersey, United States
| | - Daniel P Donnelly
- Analytical Research & Development Mass Spectrometry, MRL, Merck & Co., Inc., Kenilworth 07033, New Jersey, United States
| | - Brent Kochert
- Analytical Research & Development Mass Spectrometry, MRL, Merck & Co., Inc., Kenilworth 07033, New Jersey, United States
| | - Hillary A Schuessler
- Analytical Research & Development Mass Spectrometry, MRL, Merck & Co., Inc., Kenilworth 07033, New Jersey, United States
| | - Douglas Richardson
- Analytical Research & Development Mass Spectrometry, MRL, Merck & Co., Inc., Kenilworth 07033, New Jersey, United States
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7
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Wardman JF, Rahfeld P, Liu F, Morgan-Lang C, Sim L, Hallam SJ, Withers SG. Discovery and Development of Promiscuous O-Glycan Hydrolases for Removal of Intact Sialyl T-Antigen. ACS Chem Biol 2021; 16:2004-2015. [PMID: 34309358 DOI: 10.1021/acschembio.1c00316] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Mucin-type O-glycosylation (O-glycosylation) is a common post-translational modification that confers distinct biophysical properties to proteins and plays crucial roles in intercellular signaling. Yet, despite the importance of O-glycans, relatively few tools exist for their analysis and modification. In particular, there is a need for enzymes that can cleave the wide range of O-glycan structures found on protein surfaces, to facilitate glycan profiling and editing. Through functional metagenomic screening of the human gut microbiome, we discovered endo-O-glycan hydrolases from CAZy family GH101 that are capable of slowly cleaving the intact sialyl T-antigen trisaccharide (a ubiquitous O-glycan structure in humans) in addition to their primary activity against the T-antigen disaccharide. We then further explored this sequence space through phylogenetic profiling and analysis of representative enzymes, revealing large differences in the levels of this promiscuous activity between enzymes within the family. Through structural and sequence analysis, we identified active site residues that modulate specificity. Through subsequent rational protein engineering, we improved the activity of an enzyme identified by phylogenetic profiling sufficiently that substantial removal of the intact sialyl T-antigen from proteins could be readily achieved. Our best sialyl T-antigen hydrolase mutant, SpGH101 Q868G, is further shown to function on a number of proteins, tissues, and cells. Access to this enzyme opens up improved methodologies for unraveling the glycan code.
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Affiliation(s)
- Jacob F. Wardman
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Peter Rahfeld
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Feng Liu
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Connor Morgan-Lang
- Graduate Program in Bioinformatics, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Lyann Sim
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Steven J. Hallam
- Graduate Program in Bioinformatics, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Microbiology & Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Genome Science and Technology Program, University of British Columbia, 2329 West Mall, Vancouver, British Columbia V6T 1Z4, Canada
- Life Sciences Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
- ECOSCOPE Training Program, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Stephen G. Withers
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Genome Science and Technology Program, University of British Columbia, 2329 West Mall, Vancouver, British Columbia V6T 1Z4, Canada
- ECOSCOPE Training Program, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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8
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Hasan MM, Mimi MA, Mamun MA, Islam A, Waliullah ASM, Nabi MM, Tamannaa Z, Kahyo T, Setou M. Mass Spectrometry Imaging for Glycome in the Brain. Front Neuroanat 2021; 15:711955. [PMID: 34393728 PMCID: PMC8358800 DOI: 10.3389/fnana.2021.711955] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 07/07/2021] [Indexed: 12/12/2022] Open
Abstract
Glycans are diverse structured biomolecules that play crucial roles in various biological processes. Glycosylation, an enzymatic system through which various glycans are bound to proteins and lipids, is the most common and functionally crucial post-translational modification process. It is known to be associated with brain development, signal transduction, molecular trafficking, neurodegenerative disorders, psychopathologies, and brain cancers. Glycans in glycoproteins and glycolipids expressed in brain cells are involved in neuronal development, biological processes, and central nervous system maintenance. The composition and expression of glycans are known to change during those physiological processes. Therefore, imaging of glycans and the glycoconjugates in the brain regions has become a “hot” topic nowadays. Imaging techniques using lectins, antibodies, and chemical reporters are traditionally used for glycan detection. However, those techniques offer limited glycome detection. Mass spectrometry imaging (MSI) is an evolving field that combines mass spectrometry with histology allowing spatial and label-free visualization of molecules in the brain. In the last decades, several studies have employed MSI for glycome imaging in brain tissues. The current state of MSI uses on-tissue enzymatic digestion or chemical reaction to facilitate successful glycome imaging. Here, we reviewed the available literature that applied MSI techniques for glycome visualization and characterization in the brain. We also described the general methodologies for glycome MSI and discussed its potential use in the three-dimensional MSI in the brain.
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Affiliation(s)
- Md Mahmudul Hasan
- Department of Cellular & Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Mst Afsana Mimi
- Department of Cellular & Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Md Al Mamun
- Department of Cellular & Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Ariful Islam
- Department of Cellular & Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - A S M Waliullah
- Department of Cellular & Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Md Mahamodun Nabi
- Department of Cellular & Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Zinat Tamannaa
- Department of Cellular & Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Tomoaki Kahyo
- Department of Cellular & Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Japan.,International Mass Imaging Center, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Mitsutoshi Setou
- Department of Cellular & Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Japan.,International Mass Imaging Center, Hamamatsu University School of Medicine, Hamamatsu, Japan.,Department of Systems Molecular Anatomy, Institute for Medical Photonics Research, Preeminent Medical Photonics Education & Research Center, Hamamatsu, Japan
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9
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Spruit CM, Nemanichvili N, Okamatsu M, Takematsu H, Boons GJ, de Vries RP. N-Glycolylneuraminic Acid in Animal Models for Human Influenza A Virus. Viruses 2021; 13:815. [PMID: 34062844 PMCID: PMC8147317 DOI: 10.3390/v13050815] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/26/2021] [Accepted: 04/28/2021] [Indexed: 12/14/2022] Open
Abstract
The first step in influenza virus infection is the binding of hemagglutinin to sialic acid-containing glycans present on the cell surface. Over 50 different sialic acid modifications are known, of which N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc) are the two main species. Animal models with α2,6 linked Neu5Ac in the upper respiratory tract, similar to humans, are preferred to enable and mimic infection with unadapted human influenza A viruses. Animal models that are currently most often used to study human influenza are mice and ferrets. Additionally, guinea pigs, cotton rats, Syrian hamsters, tree shrews, domestic swine, and non-human primates (macaques and marmosets) are discussed. The presence of NeuGc and the distribution of sialic acid linkages in the most commonly used models is summarized and experimentally determined. We also evaluated the role of Neu5Gc in infection using Neu5Gc binding viruses and cytidine monophosphate-N-acetylneuraminic acid hydroxylase (CMAH)-/- knockout mice, which lack Neu5Gc and concluded that Neu5Gc is unlikely to be a decoy receptor. This article provides a base for choosing an appropriate animal model. Although mice are one of the most favored models, they are hardly naturally susceptible to infection with human influenza viruses, possibly because they express mainly α2,3 linked sialic acids with both Neu5Ac and Neu5Gc modifications. We suggest using ferrets, which resemble humans closely in the sialic acid content, both in the linkages and the lack of Neu5Gc, lung organization, susceptibility, and disease pathogenesis.
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Affiliation(s)
- Cindy M. Spruit
- Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands; (C.M.S.); (G.-J.B.)
| | - Nikoloz Nemanichvili
- Division of Pathology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands;
| | - Masatoshi Okamatsu
- Laboratory of Microbiology, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Hokkaido, Japan;
| | - Hiromu Takematsu
- Department of Molecular Cell Biology, Faculty of Medical Technology, Graduate School of Health Sciences, Fujita Health University, 1-98 Dengakugakubo, Kutsukake, Toyoake 470-1192, Aichi, Japan;
| | - Geert-Jan Boons
- Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands; (C.M.S.); (G.-J.B.)
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Robert P. de Vries
- Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands; (C.M.S.); (G.-J.B.)
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10
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Sytnyk V, Leshchyns'ka I, Schachner M. Neural glycomics: the sweet side of nervous system functions. Cell Mol Life Sci 2021; 78:93-116. [PMID: 32613283 PMCID: PMC11071817 DOI: 10.1007/s00018-020-03578-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 06/06/2020] [Accepted: 06/22/2020] [Indexed: 02/07/2023]
Abstract
The success of investigations on the structure and function of the genome (genomics) has been paralleled by an equally awesome progress in the analysis of protein structure and function (proteomics). We propose that the investigation of carbohydrate structures that go beyond a cell's metabolism is a rapidly developing frontier in our expanding knowledge on the structure and function of carbohydrates (glycomics). No other functional system appears to be suited as well as the nervous system to study the functions of glycans, which had been originally characterized outside the nervous system. In this review, we describe the multiple studies on the functions of LewisX, the human natural killer cell antigen-1 (HNK-1), as well as oligomannosidic and sialic (neuraminic) acids. We attempt to show the sophistication of these structures in ontogenetic development, synaptic function and plasticity, and recovery from trauma, with a view on neurodegeneration and possibilities to ameliorate deterioration. In view of clinical applications, we emphasize the need for glycomimetic small organic compounds which surpass the usefulness of natural glycans in that they are metabolically more stable, more parsimonious to synthesize or isolate, and more advantageous for therapy, since many of them pass the blood brain barrier and are drug-approved for treatments other than those in the nervous system, thus allowing a more ready access for application in neurological diseases. We describe the isolation of such mimetic compounds using not only Western NIH, but also traditional Chinese medical libraries. With this review, we hope to deepen the interests in this exciting field.
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Affiliation(s)
- Vladimir Sytnyk
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia.
| | - Iryna Leshchyns'ka
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Melitta Schachner
- Center for Neuroscience, Shantou University Medical College, 22 Xin Ling Road, Shantou, 515041, Guangdong, China
- Department of Cell Biology and Neuroscience, Keck Center for Collaborative Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ, 08854, USA
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11
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Altevogt P, Sammar M, Hüser L, Kristiansen G. Novel insights into the function of CD24: A driving force in cancer. Int J Cancer 2020; 148:546-559. [PMID: 32790899 DOI: 10.1002/ijc.33249] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/23/2020] [Accepted: 07/28/2020] [Indexed: 12/12/2022]
Abstract
CD24 is a highly glycosylated protein with a small protein core that is linked to the plasma membrane via a glycosyl-phosphatidylinositol anchor. CD24 is primarily expressed by immune cells but is often overexpressed in human tumors. In cancer, CD24 is a regulator of cell migration, invasion and proliferation. Its expression is associated with poor prognosis and it is used as cancer stemness marker. Recently, CD24 on tumor cells was identified as a phagocytic inhibitor ("do not eat me" signal) having a suppressive role in tumor immunity via binding to Siglec-10 on macrophages. This finding is reminiscent of the demonstration that soluble CD24-Fc can dampen the immune system in autoimmune disease. In the present review, we summarize recent progress on the role of the CD24-Siglec-10 binding axis at the interface between tumor cells and the immune system, and the role of CD24 genetic polymorphisms in cancer. We describe the specific function of cytoplasmic CD24 and discuss the presence of CD24 on tumor-released extracellular vesicles. Finally, we evaluate the potential of CD24-based immunotherapy.
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Affiliation(s)
- Peter Altevogt
- Skin Cancer Unit, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Department of Dermatology, Venereology and Allergology, University Medical Center Mannheim, Ruprecht-Karl University of Heidelberg, Mannheim, Germany
| | - Marei Sammar
- ORT Braude College for Engineering, Karmiel, Israel
| | - Laura Hüser
- Skin Cancer Unit, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Department of Dermatology, Venereology and Allergology, University Medical Center Mannheim, Ruprecht-Karl University of Heidelberg, Mannheim, Germany
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12
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Yin SS, Gao FH. Molecular Mechanism of Tumor Cell Immune Escape Mediated by CD24/Siglec-10. Front Immunol 2020; 11:1324. [PMID: 32765491 PMCID: PMC7379889 DOI: 10.3389/fimmu.2020.01324] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 05/26/2020] [Indexed: 12/11/2022] Open
Abstract
Tumor immune escape is an important part of tumorigenesis and development. Tumor cells can develop a variety of immunosuppressive mechanisms to combat tumor immunity. Exploring tumor cells that escape immune surveillance through the molecular mechanism of related immunosuppression in-depth is helpful to develop the treatment strategies of targeted tumor immune escape. The latest studies show that CD24 on the surface of tumor cells interacts with Siglec-10 on the surface of immune cells to promote the immune escape of tumor cells. It is necessary to comment on the molecular mechanism of inhibiting the activation of immune cells through the interaction between CD24 on tumor cells and Siglec-10 on immune cells, and a treatment strategy of tumors through targeting CD24 on the surface of tumor cells or Siglec-10 on immune cells.
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Affiliation(s)
- Shan-Shan Yin
- Department of Oncology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Feng-Hou Gao
- Department of Oncology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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13
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Nagae M, Yamaguchi Y, Taniguchi N, Kizuka Y. 3D Structure and Function of Glycosyltransferases Involved in N-glycan Maturation. Int J Mol Sci 2020; 21:ijms21020437. [PMID: 31936666 PMCID: PMC7014118 DOI: 10.3390/ijms21020437] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/06/2020] [Accepted: 01/08/2020] [Indexed: 12/21/2022] Open
Abstract
Glycosylation is the most ubiquitous post-translational modification in eukaryotes. N-glycan is attached to nascent glycoproteins and is processed and matured by various glycosidases and glycosyltransferases during protein transport. Genetic and biochemical studies have demonstrated that alternations of the N-glycan structure play crucial roles in various physiological and pathological events including progression of cancer, diabetes, and Alzheimer’s disease. In particular, the formation of N-glycan branches regulates the functions of target glycoprotein, which are catalyzed by specific N-acetylglucosaminyltransferases (GnTs) such as GnT-III, GnT-IVs, GnT-V, and GnT-IX, and a fucosyltransferase, FUT8s. Although the 3D structures of all enzymes have not been solved to date, recent progress in structural analysis of these glycosyltransferases has provided insights into substrate recognition and catalytic reaction mechanisms. In this review, we discuss the biological significance and structure-function relationships of these enzymes.
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Affiliation(s)
- Masamichi Nagae
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
- Correspondence: (M.N.); (Y.K.)
| | - Yoshiki Yamaguchi
- Faculty of Pharmaceutical Sciences, Tohoku Medical and Pharmaceutical University, Miyagi 981-8558, Japan;
| | - Naoyuki Taniguchi
- Department of Glyco-Oncology and Medical Biochemistry, Osaka International Cancer Institute, 3-1-69 Otemae, Chuo-ku, Osaka 541-8567, Japan;
| | - Yasuhiko Kizuka
- Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
- Correspondence: (M.N.); (Y.K.)
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14
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Gao T, Yan J, Liu CC, Palma AS, Guo Z, Xiao M, Chen X, Liang X, Chai W, Cao H. Chemoenzymatic Synthesis of O-Mannose Glycans Containing Sulfated or Nonsulfated HNK-1 Epitope. J Am Chem Soc 2019; 141:19351-19359. [PMID: 31738061 DOI: 10.1021/jacs.9b08964] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The human natural killer-1 (HNK-1) epitope is a unique sulfated trisaccharide sequence presented on O- and N-glycans of various glycoproteins and on glycolipids. It is overexpressed in the nervous system and plays crucial roles in nerve regeneration, synaptic plasticity, and neuronal diseases. However, the investigation of functional roles of HNK-1 in a more complex glycan context at the molecular level remains a big challenge due to lack of access to related structurally well-defined complex glycans. Herein, we describe a highly efficient chemoenzymatic approach for the first collective synthesis of HNK-1-bearing O-mannose glycans with different branching patterns, and for their nonsulfated counterparts. The successful strategy relies on both chemical glycosylation of a trisaccharide lactone donor for the introduction of sulfated HNK-1 branch and substrate promiscuities of bacterial glycosyltransferases that can tolerate sulfated substrates for enzymatic diversification. Glycan microarray analysis with the resulting complex synthetic glycans demonstrated their recognition by two HNK-1-specific antibodies including anti-HNK-1/N-CAM (CD57) and Cat-315, which provided further evidence for the recognition epitopes of these antibodies and the essential roles of the sulfate group for HNK-1 glycan-antibody recognition.
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Affiliation(s)
- Tian Gao
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology , Shandong University , Qingdao 266237 , China.,Laboratory for Marine Drugs and Bioproducts , Pilot National Laboratory for Marine Science and Technology (Qingdao) , Qingdao 266237 , China
| | - Jingyu Yan
- Key Laboratory of Separation Science for Analytical Chemistry , Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023 , China
| | - Chang-Cheng Liu
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology , Shandong University , Qingdao 266237 , China.,Laboratory for Marine Drugs and Bioproducts , Pilot National Laboratory for Marine Science and Technology (Qingdao) , Qingdao 266237 , China
| | - Angelina S Palma
- UCIBIO, Department of Chemistry, Faculty of Science and Technology , NOVA University of Lisbon , Caparica 2829-516 , Portugal
| | - Zhimou Guo
- Key Laboratory of Separation Science for Analytical Chemistry , Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023 , China
| | - Min Xiao
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology , Shandong University , Qingdao 266237 , China
| | - Xi Chen
- Department of Chemistry , University of California , Davis , California 95616 , United States
| | - Xinmiao Liang
- Key Laboratory of Separation Science for Analytical Chemistry , Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023 , China
| | - Wengang Chai
- The Glycosciences Laboratory, Faculty of Medicine , Imperial College London , London SW7 2AZ , United Kingdom
| | - Hongzhi Cao
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology , Shandong University , Qingdao 266237 , China.,Laboratory for Marine Drugs and Bioproducts , Pilot National Laboratory for Marine Science and Technology (Qingdao) , Qingdao 266237 , China
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15
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Larsen ISB, Narimatsu Y, Clausen H, Joshi HJ, Halim A. Multiple distinct O-Mannosylation pathways in eukaryotes. Curr Opin Struct Biol 2019; 56:171-178. [PMID: 30999272 DOI: 10.1016/j.sbi.2019.03.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/26/2019] [Accepted: 03/01/2019] [Indexed: 12/29/2022]
Abstract
Protein O-mannosylation (O-Man), originally discovered in yeast five decades ago, is an important post-translational modification (PTM) conserved from bacteria to humans, but not found in plants or nematodes. Until recently, the homologous family of ER-located protein O-mannosyl transferases (PMT1-7 in yeast; POMT1/POMT2 in humans), were the only known enzymes involved in directing O-Man biosynthesis in eukaryotes. However, recent studies demonstrate the existence of multiple distinct O-Man glycosylation pathways indicating that the genetic and biosynthetic regulation of O-Man in eukaryotes is more complex than previously envisioned. Introduction of sensitive glycoproteomics strategies provided an expansion of O-Man glycoproteomes in eukaryotes (yeast and mammalian cell lines) leading to the discovery of O-Man glycosylation on important mammalian cell adhesion (cadherin superfamily) and signaling (plexin family) macromolecules, and to the discovery of unique nucleocytoplasmic O-Man glycosylation in yeast. It is now evident that eukaryotes have multiple distinct O-Man glycosylation pathways including: i) the classical PMT1-7 and POMT1/POMT2 pathway conserved in all eukaryotes apart from plants; ii) a yet uncharacterized nucleocytoplasmic pathway only found in yeast; iii) an ER-located pathway directed by the TMTC1-4 genes found in metazoans and protists and primarily dedicated to the cadherin superfamily; and iv) a yet uncharacterized pathway found in metazoans primarily dedicated to plexins. O-Man glycosylation is thus emerging as a much more widespread and evolutionary diverse PTM with complex genetic and biosynthetic regulation. While deficiencies in the POMT1/POMT2 O-Man pathway underlie muscular dystrophies, the TMTC1-4 pathway appear to be involved in distinct congenital disorders with neurodevelopmental phenotypes. Here, we review and discuss the recent discoveries of the new non-classical O-Man glycosylation pathways, their substrates, functions and roles in disease.
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Affiliation(s)
- Ida Signe Bohse Larsen
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Yoshiki Narimatsu
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Henrik Clausen
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Hiren J Joshi
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
| | - Adnan Halim
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
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16
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Theis T, Johal AS, Kabat M, Basak S, Schachner M. Enhanced Neuronal Survival and Neurite Outgrowth Triggered by Novel Small Organic Compounds Mimicking the LewisX Glycan. Mol Neurobiol 2018; 55:8203-8215. [PMID: 29520715 PMCID: PMC6314473 DOI: 10.1007/s12035-018-0953-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Accepted: 02/05/2018] [Indexed: 02/05/2023]
Abstract
Glycosylation fine-tunes signal transduction of adhesion molecules during neural development and supports synaptic plasticity and repair after injury in the adult nervous system. One abundantly expressed neural glycan is LewisX (LeX). Although it is known that its expression starts at the formation of the neural tube during the second embryonic week in the mouse and peaks during the first postnatal week, its functional relevance is only rudimentarily understood. To gain better insights into the functions of this glycan, we identified small organic compounds that mimic structurally and functionally this glycan glycosidically linked to several neural adhesion molecules. Mimetic compounds were identified by competitive enzyme-linked immunosorbent assay (ELISA) using the LeX-specific monoclonal antibodies L5 and SSEA-1 for screening a library of small organic molecules. In this assay, antibody binding to substrate-coated LeX glycomimetic peptide is measured in the presence of compounds, allowing identification of molecules that inhibit antibody binding and thereby mimic LeX. Gossypol, orlistat, ursolic acid, folic acid, and tosufloxacin inhibited antibody binding in a concentration-dependent manner. With the aim to functionally characterize the molecular consequences of the compounds' actions, we here present evidence that, at nM concentrations, the mimetic compounds enhance neurite outgrowth and promote neuronal survival of cultured mouse cerebellar granule cells via, notably, distinct signal transduction pathways. These findings raise hopes that these LeX mimetics will be powerful tools for further studying the functions of LeX and its effects in acute and chronic nervous system disease models. It is worth mentioning in this context that the LeX compounds investigated in the present study have been clinically approved for different therapies.
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Affiliation(s)
- Thomas Theis
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08554, USA
| | - Anmol Singh Johal
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08554, USA
| | - Maciej Kabat
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08554, USA
| | - Sayantani Basak
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08554, USA
- Developmental Sciences-Safety Assessment, Genentech, 1 DNA Way, South San Francisco, CA, 94080-4990, USA
| | - Melitta Schachner
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08554, USA.
- Center for Neuroscience, Shantou University Medical College, 22 Xin Ling Road, Shantou, Guangdong, 515041, China.
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17
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Darula Z, Medzihradszky KF. Analysis of Mammalian O-Glycopeptides-We Have Made a Good Start, but There is a Long Way to Go. Mol Cell Proteomics 2017; 17:2-17. [PMID: 29162637 DOI: 10.1074/mcp.mr117.000126] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Indexed: 12/18/2022] Open
Abstract
Glycosylation is perhaps the most common post-translational modification. Recently there has been growing interest in cataloging the glycan structures, glycoproteins, and specific sites modified and deciphering the biological functions of glycosylation. Although the results are piling up for N-glycosylation, O-glycosylation is seriously trailing behind. In our review we reiterate the difficulties researchers have to overcome in order to characterize O-glycosylation. We describe how an ingenious cell engineering method delivered exciting results, and what could we gain from "wild-type" samples. Although we refer to the biological role(s) of O-glycosylation, we do not provide a complete inventory on this topic.
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Affiliation(s)
- Zsuzsanna Darula
- From the ‡Laboratory of Proteomics Research, Biological Research Centre, Hungarian Academy of Sciences, H-6726, 62 Temesvari krt, Szeged, Hungary
| | - Katalin F Medzihradszky
- From the ‡Laboratory of Proteomics Research, Biological Research Centre, Hungarian Academy of Sciences, H-6726, 62 Temesvari krt, Szeged, Hungary; .,§Department of Pharmaceutical Chemistry, School of Pharmacy, University of California San Francisco, Genentech Hall, N472A, MC 2240, 600 16th Street, San Francisco, California 94158-2517
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18
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Sheikh MO, Halmo SM, Wells L. Recent advancements in understanding mammalian O-mannosylation. Glycobiology 2017; 27:806-819. [PMID: 28810660 PMCID: PMC6082599 DOI: 10.1093/glycob/cwx062] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 06/25/2017] [Accepted: 06/28/2017] [Indexed: 02/07/2023] Open
Abstract
The post-translational glycosylation of select proteins by O-linked mannose (O-mannose or O-man) is a conserved modification from yeast to humans and has been shown to be necessary for proper development and growth. The most well studied O-mannosylated mammalian protein is α-dystroglycan (α-DG). Hypoglycosylation of α-DG results in varying severities of congenital muscular dystrophies, cancer progression and metastasis, and inhibited entry and infection of certain arenaviruses. Defects in the gene products responsible for post-translational modification of α-DG, primarily glycosyltransferases, are the basis for these diseases. The multitude of clinical phenotypes resulting from defective O-mannosylation highlights the biomedical significance of this unique modification. Elucidation of the various O-mannose biosynthetic pathways is imperative to understanding a broad range of human diseases and for the development of novel therapeutics. In this review, we will focus on recent discoveries delineating the various enzymes, structures and functions associated with O-mannose-initiated glycoproteins. Additionally, we discuss current gaps in our knowledge of mammalian O-mannosylation, discuss the evolution of this pathway, and illustrate the utility and limitations of model systems to study functions of O-mannosylation.
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Affiliation(s)
- M Osman Sheikh
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
| | - Stephanie M Halmo
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
| | - Lance Wells
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
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19
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Manya H, Endo T. Glycosylation with ribitol-phosphate in mammals: New insights into the O-mannosyl glycan. Biochim Biophys Acta Gen Subj 2017; 1861:2462-2472. [PMID: 28711406 DOI: 10.1016/j.bbagen.2017.06.024] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 06/23/2017] [Accepted: 06/26/2017] [Indexed: 01/03/2023]
Abstract
BACKGROUND O-mannosyl glycans have been found in a limited number of glycoproteins of the brain, nerves, and skeletal muscles, particularly in α-dystroglycan (α-DG). Defects in O-mannosyl glycan on α-DG are the primary cause of a group of congenital muscular dystrophies, which are collectively termed α-dystroglycanopathy. Recent studies have revealed various O-mannosyl glycan structures, which can be classified as core M1, core M2, and core M3 glycans. Although many dystroglycanopathy genes are involved in core M3 processing, the structure and biosynthesis of core M3 glycan remains only partially understood. SCOPE OF REVIEW This review presents recent findings about the structure, biosynthesis, and pathology of O-mannosyl glycans. MAJOR CONCLUSIONS Recent studies have revealed that the entire structure of core M3 glycan, including ribitol-5-phosphate, is a novel structure in mammals; its unique biosynthetic pathway has been elucidated by the identification of new causative genes for α-dystroglycanopathies and their functions. GENERAL SIGNIFICANCE O-mannosyl glycan has a novel, unique structure that is important for the maintenance of brain and muscle functions. These findings have opened up a new field in glycoscience. These studies will further contribute to the understanding of the pathomechanism of α-dystroglycanopathy and the development of glycotherapeutics. This article is part of a Special Issue entitled Neuro-glycoscience, edited by Kenji Kadomatsu and Hiroshi Kitagawa.
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Affiliation(s)
- Hiroshi Manya
- Molecular Glycobiology, Research Team for Mechanism of Aging, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Itabashi-ku, Tokyo 173-0015, Japan.
| | - Tamao Endo
- Molecular Glycobiology, Research Team for Mechanism of Aging, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Itabashi-ku, Tokyo 173-0015, Japan.
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20
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Abstract
Glycans are essential for the maintenance of normal biological function, with alterations in glycan expression being a hallmark of cancer. Cancer stem cells (CSCs) are a subset of cells within a tumour capable of self-renewal, cellular differentiation and resistances to conventional therapies. As is the case with stem cells, marker proteins present on the cell surface are frequently used to identify and enrich CSCs, with the expression of these markers statistical correlating with the likelihood of cancer recurrence and overall patient survival. As such CSC markers are of high clinical relevance. The majority of markers currently used to identify CSC populations are glycoproteins, and although the diverse biological roles for many of these markers are known, the nature and function of the glycan moiety on these glycoproteins remains to be fully elucidated. This mini-review summarises our current knowledge regarding the types and extent of CSC marker glycosylation, and the various roles that these glycans play in CSC biology, including in mediating cell adhesion, metastasis, evading apoptosis, tear shear resistance, tumour growth, maintaining pluripotency, self-renewal, trafficking, maintaining stability, maintaining enzymatic activity and aiding epithelial mesenchymal transitioning. Given that CSCs markers have multiple diverse biological functions, and are potentially of significant diagnostic and therapeutic benefit the search for new markers that are uniquely expressed on CSCs is vital to selectively target/identify this subset of cancer cells. As such we have also outlined how high-throughput lectin microarrays can be used to successfully profile the glycosylation status of CSC and to identify glyco-markers unique to CSCs.
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21
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Larsen ISB, Narimatsu Y, Joshi HJ, Yang Z, Harrison OJ, Brasch J, Shapiro L, Honig B, Vakhrushev SY, Clausen H, Halim A. Mammalian O-mannosylation of cadherins and plexins is independent of protein O-mannosyltransferases 1 and 2. J Biol Chem 2017; 292:11586-11598. [PMID: 28512129 DOI: 10.1074/jbc.m117.794487] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Indexed: 11/06/2022] Open
Abstract
Protein O-mannosylation is found in yeast and metazoans, and a family of conserved orthologous protein O-mannosyltransferases is believed to initiate this important post-translational modification. We recently discovered that the cadherin superfamily carries O-linked mannose (O-Man) glycans at highly conserved residues in specific extracellular cadherin domains, and it was suggested that the function of E-cadherin was dependent on the O-Man glycans. Deficiencies in enzymes catalyzing O-Man biosynthesis, including the two human protein O-mannosyltransferases, POMT1 and POMT2, underlie a subgroup of congenital muscular dystrophies designated α-dystroglycanopathies, because deficient O-Man glycosylation of α-dystroglycan disrupts laminin interaction with α-dystroglycan and the extracellular matrix. To explore the functions of O-Man glycans on cadherins and protocadherins, we used a combinatorial gene-editing strategy in multiple cell lines to evaluate the role of the two POMTs initiating O-Man glycosylation and the major enzyme elongating O-Man glycans, the protein O-mannose β-1,2-N-acetylglucosaminyltransferase, POMGnT1. Surprisingly, O-mannosylation of cadherins and protocadherins does not require POMT1 and/or POMT2 in contrast to α-dystroglycan, and moreover, the O-Man glycans on cadherins are not elongated. Thus, the classical and evolutionarily conserved POMT O-mannosylation pathway is essentially dedicated to α-dystroglycan and a few other proteins, whereas a novel O-mannosylation process in mammalian cells is predicted to serve the large cadherin superfamily and other proteins.
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Affiliation(s)
- Ida Signe Bohse Larsen
- From the Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark, and
| | - Yoshiki Narimatsu
- From the Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark, and
| | - Hiren Jitendra Joshi
- From the Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark, and
| | - Zhang Yang
- From the Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark, and
| | | | - Julia Brasch
- the Department of Biochemistry and Molecular Biophysics
| | - Lawrence Shapiro
- the Department of Biochemistry and Molecular Biophysics.,Zuckerman Mind Brain Behavior Institute, Department of Systems Biology, and
| | - Barry Honig
- the Department of Biochemistry and Molecular Biophysics.,Zuckerman Mind Brain Behavior Institute, Department of Systems Biology, and.,Howard Hughes Medical Institute Columbia University, New York, New York 10032
| | - Sergey Y Vakhrushev
- From the Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark, and
| | - Henrik Clausen
- From the Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark, and
| | - Adnan Halim
- From the Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark, and
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22
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Yu J, Grant OC, Pett C, Strahl S, Stahl S, Woods RJ, Westerlind U. Induction of Antibodies Directed Against Branched Core O-Mannosyl Glycopeptides-Selectivity Complimentary to the ConA Lectin. Chemistry 2017; 23:3466-3473. [PMID: 28079948 PMCID: PMC5548291 DOI: 10.1002/chem.201605627] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Indexed: 01/31/2023]
Abstract
Mammalian protein O-mannosylation, initiated by attachment of α-mannopyranose to Ser or Thr residues, comprise a group of post-translational modifications (PTMs) involved in muscle and brain development. Recent advances in glycoproteomics methodology and the "SimpleCell" strategy have enabled rapid identification of glycoproteins and specific glycosylation sites. Despite the enormous progress made, the biological impact of the mammalian O-mannosyl glycoproteome remains largely unknown to date. Tools are still needed to investigate the structure, role, and abundance of O-mannosyl glycans. Although O-mannosyl branching has been shown to be of relevance in integrin-dependent cell migration, and also plays a role in demyelinating diseases, such as multiple sclerosis, a broader understanding of the biological roles of branched O-mannosyl glycans is lacking in part due to the paucity of detection tools. In this work, a glycopeptide vaccine construct was synthesized and used to generate antibodies against branched O-mannosyl glycans. Glycopeptide microarray screening revealed high selectivity of the induced antibodies for branched glycan core structures presented on different peptide backbones, with no cross-reactivity observed with related linear glycans. For comparison, microarray screening of the mannose-binding lectin concanavalin A (ConA), which is commonly used in glycoproteomics workflows to enrich tryptic O-mannosyl peptides, showed that the ConA lectin did not recognize branched O-mannosyl glycans. The binding preference of ConA for short linear O-mannosyl glycans was rationalized in terms of molecular structure using crystallographic data augmented by molecular modeling. The contrast between the ConA binding specificity and that of the new antibodies indicates a novel role for the antibodies in studies of protein O-mannosylation.
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Affiliation(s)
- Jin Yu
- Gesellschaft zur Förderung der Analytischen Wissenschaften e.V., ISAS-Leibniz Institute for Analytical Sciences, Otto-Hahn-Str. 6b, 44227, Dortmund, Germany
| | - Oliver C Grant
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd, Athens, GA, 30602, USA
| | - Christian Pett
- Gesellschaft zur Förderung der Analytischen Wissenschaften e.V., ISAS-Leibniz Institute for Analytical Sciences, Otto-Hahn-Str. 6b, 44227, Dortmund, Germany
| | | | - Sabine Stahl
- Centre for Organismal Studies (COS), Cell Chemistry, Heidelberg University, Im Neuenheimer Feld 360, 69120, Heidelberg, Germany
| | - Robert J Woods
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd, Athens, GA, 30602, USA
| | - Ulrika Westerlind
- Gesellschaft zur Förderung der Analytischen Wissenschaften e.V., ISAS-Leibniz Institute for Analytical Sciences, Otto-Hahn-Str. 6b, 44227, Dortmund, Germany
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Mulagapati S, Koppolu V, Raju TS. Decoding of O-Linked Glycosylation by Mass Spectrometry. Biochemistry 2017; 56:1218-1226. [PMID: 28196325 DOI: 10.1021/acs.biochem.6b01244] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protein glycosylation (N- and O-linked) plays an important role in many biological processes, including protein structure and function. However, the structural elucidation of glycans, specifically O-linked glycans, remains a major challenge and is often overlooked during protein analysis. Recently, mass spectrometry (MS) has matured as a powerful technology for high-quality analytical characterization of O-linked glycans. This review summarizes the recent developments and insights of MS-based glycomics technologies, with a focus on mucin-type O-glycan analysis. Three main MS-based approaches are outlined: O-glycan profiling (structural analysis of released O-glycan), a "bottom-up" approach (analysis of an O-glycan covalently attached to a glycopeptide), and a "top-down" approach (analysis of a glycan attached to an intact glycoprotein). In addition, the most widely used MS ionization techniques, i.e., matrix-assisted laser desorption ionization and electrospray ionization, as well as ion activation techniques like collision-induced dissociation, electron capture dissociation, and electron transfer dissociation during O-glycan analysis are discussed. The MS technical approaches mentioned above are already major improvements for studying O-linked glycosylation and appear to be valuable for in-depth analysis of the type of O-glycan attached, branching patterns, and the occupancy of O-glycosylation sites.
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Affiliation(s)
- SriHariRaju Mulagapati
- Bioassay Development and Quality, Analytical Sciences, Biopharmaceutical Development, MedImmune , Gaithersburg, Maryland 20878, United States
| | - Veerendra Koppolu
- Bioassay Development and Quality, Analytical Sciences, Biopharmaceutical Development, MedImmune , Gaithersburg, Maryland 20878, United States
| | - T Shantha Raju
- Bioassay Development and Quality, Analytical Sciences, Biopharmaceutical Development, MedImmune , Gaithersburg, Maryland 20878, United States
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Anti-Neuroblastoma Properties of a Recombinant Sunflower Lectin. Int J Mol Sci 2017; 18:ijms18010092. [PMID: 28075401 PMCID: PMC5297726 DOI: 10.3390/ijms18010092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 12/18/2016] [Accepted: 12/20/2016] [Indexed: 11/17/2022] Open
Abstract
According to their sugar recognition specificity, plant lectins are proposed as bioactive proteins with potential in cancer treatment and diagnosis. Helja is a mannose-specific jacalin-like lectin from sunflower which was shown to inhibit the growth of certain fungi. Here, we report its recombinant expression in a prokaryotic system and its activity in neurobalstoma cells. Helja coding sequence was fused to the pET-32 EK/LIC, the enterokinase/Ligation-independent cloning vector and a 35 kDa protein was obtained in Escherichia coli representing Helja coupled to thioredoxin (Trx). The identity of this protein was verified using anti-Helja antibodies. This chimera, named Trx-rHelja, was enriched in the soluble bacterial extracts and was purified using Ni+2-Sepharose and d-mannose-agarose chromatography. Trx-rHelja and the enterokinase-released recombinant Helja (rHelja) both displayed toxicity on human SH-SY5Y neuroblastomas. rHelja decreased the viability of these tumor cells by 75% according to the tetrazolium reduction assay, and microscopic analyses revealed that the cell morphology was disturbed. Thus, the stellate cells of the monolayer became spheroids and were isolated. Our results indicate that rHelja is a promising tool for the development of diagnostic or therapeutic methods for neuroblastoma cells, the most common solid tumors in childhood.
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25
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Kizuka Y. Expression of Neural Glycans and Their Role in Disease. TRENDS GLYCOSCI GLYC 2017. [DOI: 10.4052/tigg.1613.2j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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26
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Kizuka Y. Expression of Neural Glycans and Their Role in Disease. TRENDS GLYCOSCI GLYC 2017. [DOI: 10.4052/tigg.1613.2e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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27
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Ayre DC, Christian SL. CD24: A Rheostat That Modulates Cell Surface Receptor Signaling of Diverse Receptors. Front Cell Dev Biol 2016; 4:146. [PMID: 28083532 PMCID: PMC5186806 DOI: 10.3389/fcell.2016.00146] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 12/09/2016] [Indexed: 12/21/2022] Open
Affiliation(s)
- D Craig Ayre
- Department of Biochemistry, Memorial University of Newfoundland St. John's, NL, Canada
| | - Sherri L Christian
- Department of Biochemistry, Memorial University of Newfoundland St. John's, NL, Canada
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28
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Sammar M, Siwetz M, Meiri H, Fleming V, Altevogt P, Huppertz B. Expression of CD24 and Siglec-10 in first trimester placenta: implications for immune tolerance at the fetal-maternal interface. Histochem Cell Biol 2016; 147:565-574. [PMID: 28012129 DOI: 10.1007/s00418-016-1531-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/08/2016] [Indexed: 12/20/2022]
Abstract
During pregnancy, the fetal-maternal interface establishes immune tolerance between the fetus and the mother. CD24, a mucin-like glycoprotein expressed at the surface of hematopoietic cells and diverse tumor cells, is known to interact with the sialic acid-binding immunoglobulin-type lectins (Siglecs). This interaction was assessed as a candidate complex for the immune suppression response in the placenta. CD24 was affinity purified from term placenta and characterized by SDS-PAGE, Western blot and ELISA. Binding of recombinant Siglecs to placental CD24 was evaluated by ELISA. The expression of CD24 and Siglec-10 in first trimester placental tissues was investigated by immunohistochemistry and immunofluorescence. Placental CD24 had an apparent molecular weight of 30-70 kDa consistent with its high degree of N- and O-linked glycosylation. EDTA-sensitive CD24-Siglec-10 interaction via the terminal sialic acid glycan residues of CD24 was observed. CD24 did not interact with Siglec-3 or Siglec-5. During the first trimester, and already in gestational week (GA) 8, CD24 showed high expression in villous and extravillous cytotrophoblasts. There was also a mild expression in stromal cells, while syncytiotrophoblasts were negative. Co-localization of CD24 with Siglec-10 was observed in endometrial glands and in first trimester decidual cells in close vicinity to extracellular trophoblasts. This study is the first to demonstrate the early presence of CD24 in the placenta cytotrophoblast layers, placental bed and maternal uterine glands. The presence of the CD24-Siglec-10 in these regions of fetal-maternal interactions suggests a possible role in mediating immune tolerance at the fetal-maternal interface.
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Affiliation(s)
- Marei Sammar
- Prof. Ephraim Katzir Department of Biotechnology Engineering, ORT Braude College, P.O. Box 78, 2161002, Karmiel, Israel.
| | - Monika Siwetz
- Institute of Cell Biology, Histology and Embryology, Medical University of Graz, 8010, Graz, Austria
| | - Hamutal Meiri
- Hy laboratories, Rehovot and TeleMarpe, Tel Aviv, Israel
| | - Viktor Fleming
- Skin Cancer Unit, DKFZ, Heidelberg, Germany.,Department of Dermatology Venereology and Allergology, University Medical Center Mannheim Ruprecht-Karl University of Heidelberg, Mannheim, Germany
| | - Peter Altevogt
- Skin Cancer Unit, DKFZ, Heidelberg, Germany.,Department of Dermatology Venereology and Allergology, University Medical Center Mannheim Ruprecht-Karl University of Heidelberg, Mannheim, Germany
| | - Berthold Huppertz
- Institute of Cell Biology, Histology and Embryology, Medical University of Graz, 8010, Graz, Austria
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29
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The CD24 surface antigen in neural development and disease. Neurobiol Dis 2016; 99:133-144. [PMID: 27993646 DOI: 10.1016/j.nbd.2016.12.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 12/12/2016] [Accepted: 12/15/2016] [Indexed: 12/11/2022] Open
Abstract
A cell's surface molecular signature enables its reciprocal interactions with the associated microenvironments in development, tissue homeostasis and pathological processes. The CD24 surface antigen (heat-stable antigen, nectadrin; small cell lung cancer antigen cluster-4) represents a prime example of a neural surface molecule that has long been known, but whose diverse molecular functions in intercellular communication we have only begun to unravel. Here, we briefly summarize the molecular fundamentals of CD24 structure and provide a comprehensive review of CD24 expression and functional studies in mammalian neural developmental systems and disease models (rodent, human). Striving for an integrated view of the intracellular signaling processes involved, we discuss the most pertinent routes of CD24-mediated signaling pathways and functional networks in neurobiology (neural migration, neurite extension, neurogenesis) and pathology (tumorigenesis, multiple sclerosis).
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30
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Postnatal Gene Therapy Improves Spatial Learning Despite the Presence of Neuronal Ectopia in a Model of Neuronal Migration Disorder. Genes (Basel) 2016; 7:genes7120105. [PMID: 27916859 PMCID: PMC5192481 DOI: 10.3390/genes7120105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 11/17/2016] [Accepted: 11/19/2016] [Indexed: 11/25/2022] Open
Abstract
Patients with type II lissencephaly, a neuronal migration disorder with ectopic neurons, suffer from severe mental retardation, including learning deficits. There is no effective therapy to prevent or correct the formation of neuronal ectopia, which is presumed to cause cognitive deficits. We hypothesized that learning deficits were not solely caused by neuronal ectopia and that postnatal gene therapy could improve learning without correcting the neuronal ectopia formed during fetal development. To test this hypothesis, we evaluated spatial learning of cerebral cortex-specific protein O-mannosyltransferase 2 (POMT2, an enzyme required for O-mannosyl glycosylation) knockout mice and compared to the knockout mice that were injected with an adeno-associated viral vector (AAV) encoding POMT2 into the postnatal brains with Barnes maze. The data showed that the knockout mice exhibited reduced glycosylation in the cerebral cortex, reduced dendritic spine density on CA1 neurons, and increased latency to the target hole in the Barnes maze, indicating learning deficits. Postnatal gene therapy restored functional glycosylation, rescued dendritic spine defects, and improved performance on the Barnes maze by the knockout mice even though neuronal ectopia was not corrected. These results indicate that postnatal gene therapy improves spatial learning despite the presence of neuronal ectopia.
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31
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Protein O-Mannosylation in the Murine Brain: Occurrence of Mono-O-Mannosyl Glycans and Identification of New Substrates. PLoS One 2016; 11:e0166119. [PMID: 27812179 PMCID: PMC5094735 DOI: 10.1371/journal.pone.0166119] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 10/24/2016] [Indexed: 12/25/2022] Open
Abstract
Protein O-mannosylation is a post-translational modification essential for correct development of mammals. In humans, deficient O-mannosylation results in severe congenital muscular dystrophies often associated with impaired brain and eye development. Although various O-mannosylated proteins have been identified in the recent years, the distribution of O-mannosyl glycans in the mammalian brain and target proteins are still not well defined. In the present study, rabbit monoclonal antibodies directed against the O-mannosylated peptide YAT(α1-Man)AV were generated. Detailed characterization of clone RKU-1-3-5 revealed that this monoclonal antibody recognizes O-linked mannose also in different peptide and protein contexts. Using this tool, we observed that mono-O-mannosyl glycans occur ubiquitously throughout the murine brain but are especially enriched at inhibitory GABAergic neurons and at the perineural nets. Using a mass spectrometry-based approach, we further identified glycoproteins from the murine brain that bear single O-mannose residues. Among the candidates identified are members of the cadherin and plexin superfamilies and the perineural net protein neurocan. In addition, we identified neurexin 3, a cell adhesion protein involved in synaptic plasticity, and inter-alpha-trypsin inhibitor 5, a protease inhibitor important in stabilizing the extracellular matrix, as new O-mannosylated glycoproteins.
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32
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Protein O-mannosylation in the early secretory pathway. Curr Opin Cell Biol 2016; 41:100-8. [DOI: 10.1016/j.ceb.2016.04.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 04/19/2016] [Accepted: 04/25/2016] [Indexed: 12/30/2022]
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33
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Dwyer CA, Esko JD. Glycan susceptibility factors in autism spectrum disorders. Mol Aspects Med 2016; 51:104-14. [PMID: 27418189 DOI: 10.1016/j.mam.2016.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 07/06/2016] [Indexed: 11/16/2022]
Abstract
Idiopathic autism spectrum disorders (ASDs) are neurodevelopmental disorders with unknown etiology. An estimated 1:68 children in the U.S. are diagnosed with ASDs, making these disorders a substantial public health issue. Recent advances in genome sequencing have identified numerous genetic variants across the ASD patient population. Many genetic variants identified occur in genes that encode glycosylated extracellular proteins (proteoglycans or glycoproteins) or enzymes involved in glycosylation (glycosyltransferases and sulfotransferases). It remains unknown whether "glycogene" variants cause changes in glycosylation and whether they contribute to the etiology and pathogenesis of ASDs. Insights into glycan susceptibility factors are provided by studies in the normal brain and congenital disorders of glycosylation, which are often accompanied by ASD-like behaviors. The purpose of this review is to present evidence that supports a contribution of extracellular glycans and glycoconjugates to the etiology and pathogenesis of idiopathic ASDs and other types of pervasive neurodevelopmental disorders.
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Affiliation(s)
- Chrissa A Dwyer
- Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jeffrey D Esko
- Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, CA 92093, USA.
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34
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Mass Spectrometry in Pharmacokinetic Studies of a Synthetic Compound for Spinal Cord Injury Treatment. BIOMED RESEARCH INTERNATIONAL 2015; 2015:169234. [PMID: 26090386 PMCID: PMC4452236 DOI: 10.1155/2015/169234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/16/2014] [Accepted: 09/16/2014] [Indexed: 11/19/2022]
Abstract
The studies of drugs that could constitute a palliative to spinal cord injury (SCI) are a continuous and increasing demand in biomedicine field from developed societies. Recently we described the chemical synthesis and antiglioma activity of synthetic glycosides. A synthetic sulfated glycolipid (here IG20) has shown chemical stability, solubility in polar solvents, and high inhibitory capacity over glioma growth. We have used mass spectrometry (MS) to monitor IG20 (m/z = 550.3) in cells and tissues of the central nervous system (CNS) that are involved in SCI recovery. IG20 was detected by MS in serum and homogenates from CNS tissue of rats, though in the latter a previous deproteinization step was required. The pharmacokinetic parameters of serum clearance at 24 h and half-life at 4 h were determined for synthetic glycoside in the adult rat using MS. A local administration of the drug near of spinal lesion site is proposed.
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35
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Harvey DJ. Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update for 2009-2010. MASS SPECTROMETRY REVIEWS 2015; 34:268-422. [PMID: 24863367 PMCID: PMC7168572 DOI: 10.1002/mas.21411] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 07/16/2013] [Accepted: 07/16/2013] [Indexed: 05/07/2023]
Abstract
This review is the sixth update of the original article published in 1999 on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2010. General aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, arrays and fragmentation are covered in the first part of the review and applications to various structural typed constitutes the remainder. The main groups of compound that are discussed in this section are oligo and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Many of these applications are presented in tabular form. Also discussed are medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis.
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Affiliation(s)
- David J. Harvey
- Department of BiochemistryOxford Glycobiology InstituteUniversity of OxfordOxfordOX1 3QUUK
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36
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Yoshida-Moriguchi T, Campbell KP. Matriglycan: a novel polysaccharide that links dystroglycan to the basement membrane. Glycobiology 2015; 25:702-13. [PMID: 25882296 PMCID: PMC4453867 DOI: 10.1093/glycob/cwv021] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 04/08/2015] [Indexed: 01/01/2023] Open
Abstract
Associations between cells and the basement membrane are critical for a variety of biological events including cell proliferation, cell migration, cell differentiation and the maintenance of tissue integrity. Dystroglycan is a highly glycosylated basement membrane receptor, and is involved in physiological processes that maintain integrity of the skeletal muscle, as well as development and function of the central nervous system. Aberrant O-glycosylation of the α subunit of this protein, and a concomitant loss of dystroglycan's ability to function as a receptor for extracellular matrix (ECM) ligands that bear laminin globular (LG) domains, occurs in several congenital/limb-girdle muscular dystrophies (also referred to as dystroglycanopathies). Recent genetic studies revealed that mutations in DAG1 (which encodes dystroglycan) and at least 17 other genes disrupt the ECM receptor function of dystroglycan and cause disease. Here, we summarize recent advances in our understanding of the enzymatic functions of two of these disease genes: the like-glycosyltransferase (LARGE) and protein O-mannose kinase (POMK, previously referred to as SGK196). In addition, we discuss the structure of the glycan that directly binds the ECM ligands and the mechanisms by which this functional motif is linked to dystroglycan. In light of the fact that dystroglycan functions as a matrix receptor and the polysaccharide synthesized by LARGE is the binding motif for matrix proteins, we propose to name this novel polysaccharide structure matriglycan.
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Affiliation(s)
- Takako Yoshida-Moriguchi
- Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Department of Neurology, Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, 4283 Carver Biomedical Research Building, 285 Newton Road, Iowa City, IA 52242-1101, USA
| | - Kevin P Campbell
- Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Department of Neurology, Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, 4283 Carver Biomedical Research Building, 285 Newton Road, Iowa City, IA 52242-1101, USA
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37
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Dwyer CA, Katoh T, Tiemeyer M, Matthews RT. Neurons and glia modify receptor protein-tyrosine phosphatase ζ (RPTPζ)/phosphacan with cell-specific O-mannosyl glycans in the developing brain. J Biol Chem 2015; 290:10256-73. [PMID: 25737452 DOI: 10.1074/jbc.m114.614099] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Indexed: 01/06/2023] Open
Abstract
Protein O-mannosylation is a glycan modification that is required for normal nervous system development and function. Mutations in genes involved in protein O-mannosyl glycosylation give rise to a group of neurodevelopmental disorders known as congenital muscular dystrophies (CMDs) with associated CNS abnormalities. Our previous work demonstrated that receptor protein-tyrosine phosphatase ζ (RPTPζ)/phosphacan is hypoglycosylated in a mouse model of one of these CMDs, known as muscle-eye-brain disease, a disorder that is caused by loss of an enzyme (protein O-mannose β-1,2-N-acetylglucosaminyltransferase 1) that modifies O-mannosyl glycans. In addition, monoclonal antibodies Cat-315 and 3F8 were demonstrated to detect O-mannosyl glycan modifications on RPTPζ/phosphacan. Here, we show that O-mannosyl glycan epitopes recognized by these antibodies define biochemically distinct glycoforms of RPTPζ/phosphacan and that these glycoforms differentially decorate the surface of distinct populations of neural cells. To provide a further structural basis for immunochemically based glycoform differences, we characterized the O-linked glycan heterogeneity of RPTPζ/phosphacan in the early postnatal mouse brain by multidimensional mass spectrometry. Structural characterization of the O-linked glycans released from purified RPTPζ/phosphacan demonstrated that this protein is a significant substrate for protein O-mannosylation and led to the identification of several novel O-mannose-linked glycan structures, including sulfo-N-acetyllactosamine containing modifications. Taken together, our results suggest that specific glycan modifications may tailor the function of this protein to the unique needs of specific cells. Furthermore, their absence in CMDs suggests that hypoglycosylation of RPTPζ/phosphacan may have different functional consequences in neurons and glia.
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Affiliation(s)
- Chrissa A Dwyer
- From the Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York 13210 and
| | - Toshihiko Katoh
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Michael Tiemeyer
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Russell T Matthews
- From the Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York 13210 and
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38
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CD24: from a Hematopoietic Differentiation Antigen to a Genetic Risk Factor for Multiple Autoimmune Diseases. Clin Rev Allergy Immunol 2015; 50:70-83. [DOI: 10.1007/s12016-015-8470-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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39
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Abstract
Most proteins are modified by glycans, which can modulate the biological properties and functions of glycoproteins. The major glycans can be classified into N-glycans and O-glycans according to their glycan-peptide linkage. This review will provide an overview of the O-mannosyl glycans, one subtype of O-glycans. Originally, O-mannosyl glycan was only known to be present on a limited number of glycoproteins, especially α-dystroglycan (α-DG). However, once a clear relationship was established between O-mannosyl glycan and the pathological mechanisms of some congenital muscular dystrophies in humans, research on the biochemistry and pathology of O-mannosyl glycans has been expanding. Because α-DG glycosylation is defective in congenital muscular dystrophies, which also feature abnormal neuronal migration, these disorders are collectively called α-dystroglycanopathies. In this article, I will describe the structure, biosynthesis and pathology of O-mannosyl glycans.
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Affiliation(s)
- Tamao Endo
- Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo 173-0015, Japan
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40
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Yaji S, Manya H, Nakagawa N, Takematsu H, Endo T, Kannagi R, Yoshihara T, Asano M, Oka S. Major glycan structure underlying expression of the Lewis X epitope in the developing brain is O-mannose-linked glycans on phosphacan/RPTPβ. Glycobiology 2014; 25:376-85. [PMID: 25361541 DOI: 10.1093/glycob/cwu118] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Glycosylation is a major protein modification. Although proteins are glycosylated/further modulated by several glycosyltransferases during trafficking from the endoplasmic reticulum to the Golgi apparatus, a certain glycan epitope has only been detected on a limited number of proteins. Of these glycan epitopes, Lewis X is highly expressed in the early stage of a developing brain and plays important roles in cell-cell interaction. The Lewis X epitope is comprised of a trisaccharide (Galβ1-4 (Fucα1-3) GlcNAc), and a key enzyme for the expression of this epitope is α1,3-fucosyltransferase 9. However, the scaffolding glycan structure responsible for the formation of the Lewis X epitope as well as its major carrier protein has not been fully characterized in the nervous system. Here we showed that the Lewis X epitope was mainly expressed on phosphacan/receptor protein tyrosine phosphatase β (RPTPβ) in the developing mouse brain. Expression of the Lewis X epitope was markedly reduced in β1,4-galactosyltransferase 2 (β4GalT2) gene-deficient mice, which indicated that β4GalT2 is a major galactosyltransferase required for the Lewis X epitope. We also showed that the Lewis X epitope almost disappeared due to the knockout of protein O-mannose β1,2-N-acetylglucosaminyltransferase 1, an N-acetylglucosaminyltransferase essential for the synthesis of O-mannosylated glycans, which indicated that the O-mannosylated glycan is responsible for presenting the Lewis X epitope. Since O-mannosylated glycans on phosphacan/RPTPβ could also present human natural killer-1, another glycan epitope specifically expressed in the nervous system, our results revealed the importance of O-mannosylated glycan chains in the presentation of functional glycan epitopes in the brain.
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Affiliation(s)
- Shohei Yaji
- Department of Biological Chemistry, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hiroshi Manya
- Molecular Glycobiology, Research Team for Mechanism of Aging, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan
| | - Naoki Nakagawa
- Department of Biological Chemistry, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hiromu Takematsu
- Department of Biological Chemistry, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Tamao Endo
- Molecular Glycobiology, Research Team for Mechanism of Aging, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan
| | - Reiji Kannagi
- Advanced Medical Research Center, Aichi Medical University, Nagakutce, Japan
| | - Toru Yoshihara
- Division of Transgenic Animal Science, Advanced Science Research Center Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Masahide Asano
- Division of Transgenic Animal Science, Advanced Science Research Center
| | - Shogo Oka
- Department of Biological Chemistry, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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41
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Levery SB, Steentoft C, Halim A, Narimatsu Y, Clausen H, Vakhrushev SY. Advances in mass spectrometry driven O-glycoproteomics. Biochim Biophys Acta Gen Subj 2014; 1850:33-42. [PMID: 25284204 DOI: 10.1016/j.bbagen.2014.09.026] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 09/24/2014] [Accepted: 09/25/2014] [Indexed: 12/13/2022]
Abstract
BACKGROUND Global analyses of proteins and their modifications by mass spectrometry are essential tools in cell biology and biomedical research. Analyses of glycoproteins represent particular challenges and we are only at the beginnings of the glycoproteomic era. Some of the challenges have been overcome with N-glycoproteins and proteome-wide analysis of N-glycosylation sites is accomplishable today but only by sacrificing information of structures at individual glycosites. More recently advances in analysis of O-glycoproteins have been made and proteome-wide analysis of O-glycosylation sites is becoming available as well. SCOPE OF REVIEW Here we discuss the challenges of analysis of O-glycans and new O-glycoproteomics strategies focusing on O-GalNAc and O-Man glycoproteomes. MAJOR CONCLUSIONS A variety of strategies are now available for proteome-wide analysis of O-glycosylation sites enabling functional studies. However, further developments are still needed for complete analysis of glycan structures at individual sites for both N- and O-glycoproteomics strategies. GENERAL SIGNIFICANCE The advances in O-glycoproteomics have led to identification of new biological functions of O-glycosylation and a new understanding of the importance of where O-glycans are positioned on proteins.
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Affiliation(s)
- Steven B Levery
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Catharina Steentoft
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Adnan Halim
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Yoshiki Narimatsu
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Henrik Clausen
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Sergey Y Vakhrushev
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
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Praissman JL, Wells L. Mammalian O-mannosylation pathway: glycan structures, enzymes, and protein substrates. Biochemistry 2014; 53:3066-78. [PMID: 24786756 PMCID: PMC4033628 DOI: 10.1021/bi500153y] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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The
mammalian O-mannosylation pathway for protein post-translational
modification is intricately involved in modulating cell–matrix
interactions in the musculature and nervous system. Defects in enzymes
of this biosynthetic pathway are causative for multiple forms of congenital
muscular dystophy. The application of advanced genetic and biochemical
technologies has resulted in remarkable progress in this field over
the past few years, culminating with the publication of three landmark
papers in 2013 alone. In this review, we will highlight recent progress
focusing on the dramatic expansion of the set of genes known to be
involved in O-mannosylation and disease processes, the concurrent
acceleration of the rate of O-mannosylation pathway protein functional
assignments, the tremendous increase in the number of proteins now
known to be modified by O-mannosylation, and the recent progress in
protein O-mannose glycan quantification and site assignment. Also,
we attempt to highlight key outstanding questions raised by this abundance
of new information.
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Affiliation(s)
- Jeremy L Praissman
- Complex Carbohydrate Research Center, Department of Biochemistry and Molecular Biology, The University of Georgia , Athens, Georgia 30602, United States
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Yu J, Westerlind U. Synthesis of a glycopeptide vaccine conjugate for induction of antibodies recognizing O-mannosyl glycopeptides. Chembiochem 2014; 15:939-45. [PMID: 24753400 DOI: 10.1002/cbic.201300537] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 01/30/2014] [Indexed: 01/30/2023]
Abstract
In spite of the clear importance of protein O-mannosylation in brain glycobiology, tools are lacking for specific detection, enrichment, and identification of proteins containing these modifycations. We envisioned inducing antibodies that specifically recognize O-mannose glycans on proteins and peptides. With this in mind, we prepared a glycopeptide vaccine construct containing the N-acetyllactosamine-extended mannose motif Galβ1-4GlcNAcβ1-2ManαThr, found as a common core structure on almost all mammalian O-mannosyl glycoproteins identified. O-mannose glycosylated amino acid building blocks and the corresponding glycopeptides were prepared by chemical synthesis and then conjugated to an immune carrier protein. After administration of the synthetic vaccine into rabbits, strong immune responses were obtained. Further evaluation by ELISA neutralization experiments and glycopeptide microarrays showed that the induced antibodies were highly specific to the glycopeptide antigen.
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Affiliation(s)
- Jin Yu
- Gesellschaft zur Förderung der Analytischen Wissenschaften e.V. ISAS-Leibniz Institute for Analytical Sciences, Otto-Hahn-Str. 6b, 44227 Dortmund (Germany)
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Panin VM, Wells L. Protein O-mannosylation in metazoan organisms. CURRENT PROTOCOLS IN PROTEIN SCIENCE 2014; 75:12.12.1-12.12.29. [PMID: 24510673 PMCID: PMC3984005 DOI: 10.1002/0471140864.ps1212s75] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Protein O-mannosylation is a special type of glycosylation that plays prominent roles in metazoans, affecting development and physiology of the nervous system and muscles. A major biological effect of O-mannosylation involves the regulation of α-dystroglycan, a membrane glycoprotein mediating cell-extracellular matrix interactions. Genetic defects of O-mannosylation result in the loss of ligand-binding activity of α-dystroglycan and cause congenital muscular dystrophies termed dystroglycanopathies. Recent progress in mass spectrometry and in vitro analyses has shed new light on the mechanism of α-dystroglycan glycosylation; however, this mechanism is underlain by complex genetic and molecular elements that remain poorly understood. Protein O-mannosylation is evolutionarily conserved in metazoans, yet the pathway is simplified and more amenable to genetic analyses in invertebrate organisms, indicating that genetically tractable in vivo models could facilitate research in this area. This unit describes recent methodological strategies for studying protein O-mannosylation using in vitro and in vivo approaches.
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Affiliation(s)
- Vladislav M. Panin
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843; Tel. 979-458-4630, FAX 979-845-9274
| | - Lance Wells
- Complex Carbohydrate Research Center, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602; Tel 706-542-7806, FAX 706-542-4412
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Use of Glycan-Targeted Antibodies/Lectins to Study the Expression/Function of Glycosyltransferases in the Nervous System. ADVANCES IN NEUROBIOLOGY 2014; 9:117-27. [DOI: 10.1007/978-1-4939-1154-7_6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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46
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Morise J, Kizuka Y, Yabuno K, Tonoyama Y, Hashii N, Kawasaki N, Manya H, Miyagoe-Suzuki Y, Takeda S, Endo T, Maeda N, Takematsu H, Oka S. Structural and biochemical characterization of O-mannose-linked human natural killer-1 glycan expressed on phosphacan in developing mouse brains. Glycobiology 2013; 24:314-24. [DOI: 10.1093/glycob/cwt116] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Protein O-mannosylation is crucial for E-cadherin-mediated cell adhesion. Proc Natl Acad Sci U S A 2013; 110:21024-9. [PMID: 24297939 DOI: 10.1073/pnas.1316753110] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In recent years protein O-mannosylation has become a focus of attention as a pathomechanism underlying severe congenital muscular dystrophies associated with neuronal migration defects. A key feature of these disorders is the lack of O-mannosyl glycans on α-dystroglycan, resulting in abnormal basement membrane formation. Additional functions of O-mannosylation are still largely unknown. Here, we identify the essential cell-cell adhesion glycoprotein epithelial (E)-cadherin as an O-mannosylated protein and establish a functional link between O-mannosyl glycans and cadherin-mediated cell-cell adhesion. By genetically and pharmacologically blocking protein O-mannosyltransferases, we found that this posttranslational modification is essential for preimplantation development of the mouse embryo. O-mannosylation-deficient embryos failed to proceed from the morula to the blastocyst stage because of defects in the molecular architecture of cell-cell contact sites, including the adherens and tight junctions. Using mass spectrometry, we demonstrate that O-mannosyl glycans are present on E-cadherin, the major cell-adhesion molecule of blastomeres, and present evidence that this modification is generally conserved in cadherins. Further, the use of newly raised antibodies specific for an O-mannosyl-conjugated epitope revealed that these glycans are present on early mouse embryos. Finally, our cell-aggregation assays demonstrated that O-mannosyl glycans are crucial for cadherin-based cell adhesion. Our results redefine the significance of O-mannosylation in humans and other mammals, showing the immense impact of cadherins on normal as well as pathogenic cell behavior.
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Live D, Wells L, Boons GJ. Dissecting the molecular basis of the role of the O-mannosylation pathway in disease: α-dystroglycan and forms of muscular dystrophy. Chembiochem 2013; 14:2392-402. [PMID: 24318691 DOI: 10.1002/cbic.201300417] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Indexed: 11/10/2022]
Abstract
Dystroglycanopathies form a subgroup of muscular dystrophies that arise from defects in enzymes that are implicated in the recently elucidated O-mannosylation pathway, thereby resulting in underglycosylation of α-dystroglycan. The emerging identification of additional brain proteins modified by O-mannosylation provides a broader context for interpreting the range of neurological consequences associated with dystroglycanopathies. This form of glycosylation is associated with protein mucin-like domains that present numerous serine and threonine residues as possible sites for modification. Furthermore, the O-Man glycans coexist in this region with O-GalNAc glycans (conventionally associated with such protein sequences), thus resulting in a complex glycoconjugate landscape. Sorting out the relationships between the various molecular defects in glycosylation and the modes of disease presentation, as well as the regulatory interplay among the O-Man glycans and the effects on other modes of glycosylation in the same domain, is challenging. Here we provide a perspective on chemical biology approaches employing synthetic and analytical methods to address these questions.
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Affiliation(s)
- David Live
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA)
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Mining the O-mannose glycoproteome reveals cadherins as major O-mannosylated glycoproteins. Proc Natl Acad Sci U S A 2013; 110:21018-23. [PMID: 24101494 DOI: 10.1073/pnas.1313446110] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The metazoan O-mannose (O-Man) glycoproteome is largely unknown. It has been shown that up to 30% of brain O-glycans are of the O-Man type, but essentially only alpha-dystroglycan (α-DG) of the dystrophin-glycoprotein complex is well characterized as an O-Man glycoprotein. Defects in O-Man glycosylation underlie congenital muscular dystrophies and considerable efforts have been devoted to explore this O-glycoproteome without much success. Here, we used our SimpleCell strategy using nuclease-mediated gene editing of a human cell line (MDA-MB-231) to reduce the structural heterogeneity of O-Man glycans and to probe the O-Man glycoproteome. In this breast cancer cell line we found that O-Man glycosylation is primarily found on cadherins and plexins on β-strands in extracellular cadherin and Ig-like, plexin and transcription factor domains. The positions and evolutionary conservation of O-Man glycans in cadherins suggest that they play important functional roles for this large group of cell adhesion glycoproteins, which can now be addressed. The developed O-Man SimpleCell strategy is applicable to most types of cell lines and enables proteome-wide discovery of O-Man protein glycosylation.
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Winterhalter PR, Lommel M, Ruppert T, Strahl S. O-glycosylation of the non-canonical T-cadherin from rabbit skeletal muscle by single mannose residues. FEBS Lett 2013; 587:3715-21. [DOI: 10.1016/j.febslet.2013.09.041] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 09/16/2013] [Accepted: 09/23/2013] [Indexed: 11/28/2022]
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