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Lund SJ, Del Rosario PGB, Honda A, Caoili KJ, Hoeksema MA, Nizet V, Patras KA, Prince LS. Sialic Acid-Siglec-E Interactions Regulate the Response of Neonatal Macrophages to Group B Streptococcus. Immunohorizons 2024; 8:384-396. [PMID: 38809232 PMCID: PMC11150127 DOI: 10.4049/immunohorizons.2300076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 04/24/2024] [Indexed: 05/30/2024] Open
Abstract
The mammalian Siglec receptor sialoadhesin (Siglec1, CD169) confers innate immunity against the encapsulated pathogen group B Streptococcus (GBS). Newborn lung macrophages have lower expression levels of sialoadhesin at birth compared with the postnatal period, increasing their susceptibility to GBS infection. In this study, we investigate the mechanisms regulating sialoadhesin expression in the newborn mouse lung. In both neonatal and adult mice, GBS lung infection reduced Siglec1 expression, potentially delaying acquisition of immunity in neonates. Suppression of Siglec1 expression required interactions between sialic acid on the GBS capsule and the inhibitory host receptor Siglec-E. The Siglec1 gene contains multiple STAT binding motifs, which could regulate expression of sialoadhesin downstream of innate immune signals. Although GBS infection reduced STAT1 expression in the lungs of wild-type newborn mice, we observed increased numbers of STAT1+ cells in Siglece-/- lungs. To test if innate immune activation could increase sialoadhesin at birth, we first demonstrated that treatment of neonatal lung macrophages ex vivo with inflammatory activators increased sialoadhesin expression. However, overcoming the low sialoadhesin expression at birth using in vivo prenatal exposures or treatments with inflammatory stimuli were not successful. The suppression of sialoadhesin expression by GBS-Siglec-E engagement may therefore contribute to disease pathogenesis in newborns and represent a challenging but potentially appealing therapeutic opportunity to augment immunity at birth.
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MESH Headings
- Animals
- Mice
- Streptococcus agalactiae/immunology
- Animals, Newborn
- N-Acetylneuraminic Acid/metabolism
- Sialic Acid Binding Ig-like Lectin 1/metabolism
- Streptococcal Infections/immunology
- Streptococcal Infections/microbiology
- STAT1 Transcription Factor/metabolism
- STAT1 Transcription Factor/genetics
- Mice, Knockout
- Immunity, Innate
- Mice, Inbred C57BL
- Lung/immunology
- Lung/microbiology
- Lung/metabolism
- Macrophages, Alveolar/immunology
- Macrophages, Alveolar/metabolism
- Female
- Macrophages/immunology
- Macrophages/metabolism
- Lectins/metabolism
- Lectins/genetics
- Sialic Acid Binding Immunoglobulin-like Lectins/metabolism
- Sialic Acid Binding Immunoglobulin-like Lectins/genetics
- Antigens, CD/metabolism
- Antigens, CD/genetics
- Antigens, Differentiation, B-Lymphocyte
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Affiliation(s)
- Sean J. Lund
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
| | - Pamela G. B. Del Rosario
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
- Rady Children’s Hospital, San Diego, CA
| | - Asami Honda
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
| | | | - Marten A. Hoeksema
- Department of Medical Biochemistry, Amsterdam University Medical Center, Amsterdam Zuidoost, the Netherlands
| | - Victor Nizet
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
| | - Kathryn A. Patras
- Department of Molecular Virology and Microbiology, Alkek Center for Metagenomics and Microbiome Research, Baylor College of Medicine, Houston, TX
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2
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Ayyalasomayajula R, Cudic M. Targeting Siglec-Sialylated MUC1 Immune Axis in Cancer. Cancers (Basel) 2024; 16:1334. [PMID: 38611013 PMCID: PMC11011055 DOI: 10.3390/cancers16071334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 03/12/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024] Open
Abstract
Siglecs play a key role in mediating cell-cell interactions via the recognition of different sialylated glycoconjugates, including tumor-associated MUC1, which can lead to the activation or inhibition of the immune response. The activation occurs through the signaling of Siglecs with the cytoplasmic immunoreceptor tyrosine-based activation motif (ITAM)-containing proteins, while the inhibition signal is a result of the interaction of intracellular immunoreceptor tyrosine-based inhibition motif (ITIM)-bearing receptors. The interaction of tumor-associated MUC1 sialylated glycans with Siglecs via ITIM motifs decreases antitumor immunity. Consequently, these interactions are expected to play a key role in tumor evasion. Efforts to modulate the response of immune cells by blocking the immune-suppressive effects of inhibitory Siglecs, driving immune-activating Siglecs, and/or altering the synthesis and expression of the sialic acid glycocalyx are new therapeutic strategies deserving further investigation. We will highlight the role of Siglec's family receptors in immune evasion through interactions with glycan ligands in their natural context, presented on the protein such as MUC1, factors affecting their fine binding specificities, such as the role of multivalency either at the ligand or receptor side, their spatial organization, and finally the current and future therapeutic interventions targeting the Siglec-sialylated MUC1 immune axis in cancer.
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Affiliation(s)
| | - Mare Cudic
- Department of Chemistry and Biochemistry, Florida Atlantic University, 777 Glades Rd., Boca Raton, FL 33431, USA;
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3
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Chen Y, Chen H, Zheng Q. Siglecs family used by pathogens for immune escape may engaged in immune tolerance in pregnancy. J Reprod Immunol 2023; 159:104127. [PMID: 37572430 DOI: 10.1016/j.jri.2023.104127] [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: 05/08/2023] [Revised: 07/18/2023] [Accepted: 08/02/2023] [Indexed: 08/14/2023]
Abstract
The Siglecs family is a group of type I sialic acid-binding immunoglobulin-like receptors that regulate cellular signaling by recognizing sialic acid epitopes. Siglecs are predominantly expressed on the surface of leukocytes, where they play a crucial role in regulating immune activity. Pathogens can exploit inhibitory Siglecs by utilizing their sialic acid components to promote invasion or suppress immune functions, facilitating immune evasion. The establishing of an immune-balanced maternal-fetal interface microenvironment is essential for a successful pregnancy. Dysfunctional immune cells may lead to adverse pregnancy outcomes. Siglecs are important for inducing a phenotypic switch in leukocytes at the maternal-fetal interface toward a less toxic and more tolerant phenotype. Recent discoveries regarding Siglecs in the reproductive system have drawn further attention to their potential roles in reproduction. In this review, we primarily discuss the latest advances in understanding the impact of Siglecs as immune regulators on infections and pregnancy.
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Affiliation(s)
- Ying Chen
- Prenatal Diagnosis Center, The Eighth Affiliated Hospital, Sun Yat-sen University, 3025# Shennan Road, Shenzhen 518033, PR China
| | - Huan Chen
- Prenatal Diagnosis Center, The Eighth Affiliated Hospital, Sun Yat-sen University, 3025# Shennan Road, Shenzhen 518033, PR China
| | - Qingliang Zheng
- Prenatal Diagnosis Center, The Eighth Affiliated Hospital, Sun Yat-sen University, 3025# Shennan Road, Shenzhen 518033, PR China.
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4
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Gretenkort L, Thiesler H, Hildebrandt H. Neuroimmunomodulatory properties of polysialic acid. Glycoconj J 2023; 40:277-294. [PMID: 37171513 DOI: 10.1007/s10719-023-10120-z] [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: 11/15/2022] [Revised: 11/16/2022] [Accepted: 05/02/2023] [Indexed: 05/13/2023]
Abstract
Polymeric sialic acid (polysialic acid, polySia) is a remarkable posttranslational modification of only few select proteins. The major, and most prominent polySia protein carrier is the neural cell adhesion molecule NCAM. Here, the key functions of polySia are to regulate interactions of NCAM and to balance cellular interactions in brain development and plasticity. During recent years, however, increasing evidence points towards a role of polySia in the modulation of immune responses. These immunomodulatory functions can be mediated by polySia on proteins other than NCAM, presented either on the cell surface or released into the extracellular space. This perspective review summarizes our current knowledge and addresses major open questions on polySia and polySia receptors in modulating innate immune responses in the brain.
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Affiliation(s)
- Lina Gretenkort
- Institute of Clinical Biochemistry, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany
| | - Hauke Thiesler
- Institute of Clinical Biochemistry, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany
| | - Herbert Hildebrandt
- Institute of Clinical Biochemistry, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
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5
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Raïch-Regué D, Resa-Infante P, Gallemí M, Laguia F, Muñiz-Trabudua X, Muñoz-Basagoiti J, Perez-Zsolt D, Chojnacki J, Benet S, Clotet B, Martinez-Picado J, Izquierdo-Useros N. Role of Siglecs in viral infections: A double-edged sword interaction. Mol Aspects Med 2023; 90:101113. [PMID: 35981912 PMCID: PMC9923124 DOI: 10.1016/j.mam.2022.101113] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 07/25/2022] [Accepted: 08/01/2022] [Indexed: 01/21/2023]
Abstract
Sialic-acid-binding immunoglobulin-like lectins are cell surface immune receptors known as Siglecs that play a paramount role as modulators of immunity. In recent years, research has underscored how the underlaying biology of this family of receptors influences the outcome of viral infections. While Siglecs are needed to promote effective antiviral immune responses, they can also pave the way to viral dissemination within tissues. Here, we review how recent preclinical findings focusing on the interplay between Siglecs and viruses may translate into promising broad-spectrum therapeutic interventions or key biomarkers to monitor the course of viral infections.
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Affiliation(s)
- Dàlia Raïch-Regué
- IrsiCaixa AIDS Research Institute, Hospital Germans Trias i Pujol, 08916, Badalona, Spain
| | - Patricia Resa-Infante
- IrsiCaixa AIDS Research Institute, Hospital Germans Trias i Pujol, 08916, Badalona, Spain; University of Vic-Central University of Catalonia (UVic-UCC), 08500, Vic, Spain
| | - Marçal Gallemí
- IrsiCaixa AIDS Research Institute, Hospital Germans Trias i Pujol, 08916, Badalona, Spain
| | - Fernando Laguia
- IrsiCaixa AIDS Research Institute, Hospital Germans Trias i Pujol, 08916, Badalona, Spain
| | - Xabier Muñiz-Trabudua
- IrsiCaixa AIDS Research Institute, Hospital Germans Trias i Pujol, 08916, Badalona, Spain
| | | | - Daniel Perez-Zsolt
- IrsiCaixa AIDS Research Institute, Hospital Germans Trias i Pujol, 08916, Badalona, Spain
| | - Jakub Chojnacki
- IrsiCaixa AIDS Research Institute, Hospital Germans Trias i Pujol, 08916, Badalona, Spain; Germans Trias i Pujol Research Institute (IGTP), Can Ruti Campus, 08916, Badalona, Spain
| | - Susana Benet
- Fundació lluita contra la SIDA, Infectious Diseases Department, Hospital Germans Trias i Pujol, 08916, Badalona, Spain
| | - Bonaventura Clotet
- IrsiCaixa AIDS Research Institute, Hospital Germans Trias i Pujol, 08916, Badalona, Spain; University of Vic-Central University of Catalonia (UVic-UCC), 08500, Vic, Spain; Germans Trias i Pujol Research Institute (IGTP), Can Ruti Campus, 08916, Badalona, Spain; Fundació lluita contra la SIDA, Infectious Diseases Department, Hospital Germans Trias i Pujol, 08916, Badalona, Spain; Consorcio Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Javier Martinez-Picado
- IrsiCaixa AIDS Research Institute, Hospital Germans Trias i Pujol, 08916, Badalona, Spain; University of Vic-Central University of Catalonia (UVic-UCC), 08500, Vic, Spain; Germans Trias i Pujol Research Institute (IGTP), Can Ruti Campus, 08916, Badalona, Spain; Consorcio Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029, Madrid, Spain; Catalan Institution for Research and Advanced Studies (ICREA), 08010, Barcelona, Spain
| | - Nuria Izquierdo-Useros
- IrsiCaixa AIDS Research Institute, Hospital Germans Trias i Pujol, 08916, Badalona, Spain; Germans Trias i Pujol Research Institute (IGTP), Can Ruti Campus, 08916, Badalona, Spain; Consorcio Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029, Madrid, Spain.
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6
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Angata T, Varki A. Discovery, classification, evolution and diversity of Siglecs. Mol Aspects Med 2023; 90:101117. [PMID: 35989204 PMCID: PMC9905256 DOI: 10.1016/j.mam.2022.101117] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 08/03/2022] [Accepted: 08/06/2022] [Indexed: 02/08/2023]
Abstract
Immunoglobulin (Ig) superfamily proteins play diverse roles in vertebrates, including regulation of cellular responses by sensing endogenous or exogenous ligands. Siglecs are a family of glycan-recognizing proteins belonging to the Ig superfamily (i.e., I-type lectins). Siglecs are expressed on various leukocyte types and are involved in diverse aspects of immunity, including the regulation of inflammatory responses, leukocyte proliferation, host-microbe interaction, and cancer immunity. Sialoadhesin/Siglec-1, CD22/Siglec-2, and myelin-associated glycoprotein/Siglec-4 were among the first to be characterized as members of the Siglec family, and along with Siglec-15, they are relatively well-conserved among tetrapods. Conversely, CD33/Siglec-3-related Siglecs (CD33rSiglecs, so named as they show high sequence similarity with CD33/Siglec-3) are encoded in a gene cluster with many interspecies variations and even intraspecies variations within some lineages such as humans. The rapid evolution of CD33rSiglecs expressed on leukocytes involved in innate immunity likely reflects the selective pressure by pathogens that interact and possibly exploit these Siglecs. Human Siglecs have several additional unique and/or polymorphic properties as compared with closely related great apes, changes possibly related to the loss of the sialic acid Neu5Gc, another distinctly human event in sialobiology. Multiple changes in human CD33rSiglecs compared to great apes include many examples of human-specific expression in non-immune cells, coinciding with human-specific diseases involving such cell types. Some Siglec gene polymorphisms have dual consequences-beneficial in a situation but detrimental in another. The association of human Siglec gene polymorphisms with several infectious and non-infectious diseases likely reflects the ongoing competition between the host and microbial pathogens.
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Affiliation(s)
- Takashi Angata
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan.
| | - Ajit Varki
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA.
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7
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Siew JJ, Chern Y, Khoo KH, Angata T. Roles of Siglecs in neurodegenerative diseases. Mol Aspects Med 2023; 90:101141. [PMID: 36089405 DOI: 10.1016/j.mam.2022.101141] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/16/2022] [Accepted: 08/29/2022] [Indexed: 02/08/2023]
Abstract
Microglia are resident myeloid cells in the central nervous system (CNS) with a unique developmental origin, playing essential roles in developing and maintaining the CNS environment. Recent studies have revealed the involvement of microglia in neurodegenerative diseases, such as Alzheimer's disease, through the modulation of neuroinflammation. Several members of the Siglec family of sialic acid recognition proteins are expressed on microglia. Since the discovery of the genetic association between a polymorphism in the CD33 gene and late-onset Alzheimer's disease, significant efforts have been made to elucidate the molecular mechanism underlying the association between the polymorphism and Alzheimer's disease. Furthermore, recent studies have revealed additional potential associations between Siglecs and Alzheimer's disease, implying that the reduced signal from inhibitory Siglec may have an overall protective effect in lowering the disease risk. Evidences suggesting the involvement of Siglecs in other neurodegenerative diseases are also emerging. These findings could help us predict the roles of Siglecs in other neurodegenerative diseases. However, little is known about the functionally relevant Siglec ligands in the brain, which represents a new frontier. Understanding how microglial Siglecs and their ligands in CNS contribute to the regulation of CNS homeostasis and pathogenesis of neurodegenerative diseases may provide us with a new avenue for disease prevention and intervention.
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Affiliation(s)
- Jian Jing Siew
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yijuang Chern
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Kay-Hooi Khoo
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Takashi Angata
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan.
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8
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Crider J, Wilson M, Felch KL, Dupre RA, Quiniou SMA, Bengtén E. A subset of leukocyte immune-type receptors (LITRs) regulates phagocytosis in channel catfish (Ictalurus punctatus) leukocytes. Mol Immunol 2023; 154:33-44. [PMID: 36586386 DOI: 10.1016/j.molimm.2022.12.009] [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: 09/30/2022] [Revised: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 12/31/2022]
Abstract
Channel catfish, Ictalurus punctatus, leukocyte immune-type receptors (LITRs) constitute a large family of paired, immunoregulatory receptors unique to teleosts. A role for LITRs in phagocytosis has been proposed based on studies in mammalian cell lines; however, LITR-mediated phagocytosis has not been examined in the catfish model. In this study, we use two anti-LITR monoclonal antibodies, CC41 and 125.2, to contrast the effects of crosslinking subsets of inhibitory and activating LITRs. Briefly, LITRs expressed by catfish γδ T cells, αβ T cells, and macrophage cell lines were crosslinked using mAb-conjugated fluorescent microbeads, and bead uptake was evaluated by flow cytometry and confirmed by confocal microscopy. A clear difference in the uptake of 125.2- and CC41-conjugated beads was observed. Crosslinking LITRs with mAb 125.2 resulted in efficient bead internalization, while mAb CC41 crosslinking of inhibitory LITRs resulted predominantly in a capturing phenotype. Pretreating catfish macrophages with mAb CC41 resulted in a marked decrease in LITR-mediated phagocytosis of 125.2-conjugated beads. Overall, these findings provide insight into fish immunobiology and validate LITRs as regulators of phagocytosis in catfish macrophages and γδ T cells.
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Affiliation(s)
- Jonathan Crider
- Center for Immunology and Microbial Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA; Department of Cell and Molecular Biology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
| | - Melanie Wilson
- Center for Immunology and Microbial Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA; Department of Cell and Molecular Biology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
| | - Kristianna L Felch
- Center for Immunology and Microbial Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA; Department of Cell and Molecular Biology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
| | - Rebecca A Dupre
- Oak Ridge Institute for Science and Education, US Department of Energy, 1299 Bethel Valley Rd, Oak Ridge, TN 37831-0117, USA; Food Processing and Sensory Quality Unit, USDA-ARS, 1100 Allen Toussaint Blvd, New Orleans, LA 70124, USA.
| | - Sylvie M A Quiniou
- Warmwater Aquaculture Research Unit, USDA-ARS-WARU, P.O. BOX 38, Stoneville, MS 38776, USA.
| | - Eva Bengtén
- Center for Immunology and Microbial Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA; Department of Cell and Molecular Biology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
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9
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Huang R, Zheng J, Shao Y, Zhu L, Yang T. Siglec-15 as multifunctional molecule involved in osteoclast differentiation, cancer immunity and microbial infection. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 177:34-41. [PMID: 36265694 DOI: 10.1016/j.pbiomolbio.2022.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 09/19/2022] [Accepted: 10/13/2022] [Indexed: 11/06/2022]
Abstract
Siglec-15 is a highly conserved member of the Siglec family, expressed on osteoclasts, a subset of myeloid cells and some cancer cells. Except for regulating osteoclast differentiation, Siglec-15 engages in immunoregulation as an immune suppressor. Siglec-15 functions as an immunosuppressive molecule in tumor-associated macrophage-mediated T cell immunity in the tumor microenvironment (TME), which makes Siglec-15 to be an emerging and promising target for normalization cancer immunotherapy. Besides, Siglec-15 interacts with sialylated pathogens and modulates host immune response against microbial pathogens by altering cytokine production and/or phagocytosis, which further broadens the underlying pathophysiological roles of Siglec-15. The fact that N-glycosylation and sialylation of Siglec-15 play a pivotal role in Siglec-15 biological function indicates that targeting certain post-translational modification may be an effective strategy for targeting Siglec-15 therapy. In-depth exploring Siglec-15 biology function is crucial for better design of Siglec-15-based therapy according to different clinical indications.
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Affiliation(s)
- Rui Huang
- Department of Biochemistry & Molecular Biology, Shanxi Medical University, Taiyuan, China; Department of Clinical Laboratory, Children's Hospital and Women Health Center of Shanxi, Taiyuan, China
| | - Jinxiu Zheng
- Department of Biochemistry & Molecular Biology, Shanxi Medical University, Taiyuan, China; Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, Taiyuan, China
| | - Ying Shao
- Department of Pathophysiology, Shanxi Medical University, Taiyuan, China
| | - Lei Zhu
- Department of Clinical Laboratory, Children's Hospital and Women Health Center of Shanxi, Taiyuan, China
| | - Tao Yang
- Department of Biochemistry & Molecular Biology, Shanxi Medical University, Taiyuan, China; Key Laboratory of Cellular Physiology (Shanxi Medical University), Ministry of Education, Taiyuan, China.
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10
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Läubli H, Nalle SC, Maslyar D. Targeting the Siglec-Sialic Acid Immune Axis in Cancer: Current and Future Approaches. Cancer Immunol Res 2022; 10:1423-1432. [PMID: 36264237 PMCID: PMC9716255 DOI: 10.1158/2326-6066.cir-22-0366] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 07/08/2022] [Accepted: 09/01/2022] [Indexed: 01/10/2023]
Abstract
The sialic acid-binding immunoglobulin-like lectin (Siglec)-sialic acid immune axis is an evolutionarily conserved immunoregulatory pathway that provides a mechanism for establishing self-recognition and combatting invasive pathogens. Perturbations in the pathway lead to many immune dysregulated diseases, including autoimmunity, neurodegeneration, allergic conditions, and cancer. The purpose of this review is to provide a brief overview of the relationship between Siglecs and sialic acid as they relate to human health and disease, to consider current Siglec-based therapeutics, and to discuss new therapeutic approaches targeting the Siglec-sialic acid immune axis, with a focus on cancer.
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Affiliation(s)
- Heinz Läubli
- Laboratory for Cancer Immunotherapy, Department of Biomedicine, University, of Basel, Basel, Switzerland.,Division of Oncology, University Hospital Basel, Basel, Switzerland.,Corresponding Author: Heinz Läubli, University Hospital Basel, Petersgraben 4, Basel 4031, Switzerland. Phone: 416-1556-5212; Fax: 416-1265-5316; E-mail:
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11
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The new progress in cancer immunotherapy. Clin Exp Med 2022:10.1007/s10238-022-00887-0. [DOI: 10.1007/s10238-022-00887-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/30/2022] [Indexed: 12/12/2022]
Abstract
AbstractThe cross talk between immune and non-immune cells in the tumor microenvironment leads to immunosuppression, which promotes tumor growth and survival. Immunotherapy is an advanced treatment that boosts humoral and cellular immunity rather than using chemotherapy or radiation-based strategy associated with non-specific targets and toxic effects on normal cells. Immune checkpoint inhibitors and T cell-based immunotherapy have already exhibited significant effects against solid tumors and leukemia. Tumor cells that escape immune surveillance create a major obstacle to acquiring an effective immune response in cancer patients. Tremendous progress had been made in recent years on a wide range of innate and adaptive immune checkpoints which play a significant role to prevent tumorigenesis, and might therefore be potential targets to suppress tumor cells growth. This review aimed to summarize the underlying molecular mechanisms of existing immunotherapy approaches including T cell and NK-derived immune checkpoint therapy, as well as other intrinsic and phagocytosis checkpoints. Together, these insights will pave the way for new innate and adaptive immunomodulatory targets for the development of highly effective new therapy in the future.
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12
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Aberrant Sialylation in Cancer: Therapeutic Opportunities. Cancers (Basel) 2022; 14:cancers14174248. [PMID: 36077781 PMCID: PMC9454432 DOI: 10.3390/cancers14174248] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/15/2022] [Accepted: 08/23/2022] [Indexed: 11/16/2022] Open
Abstract
The surface of every eukaryotic cell is coated in a thick layer of glycans that acts as a key interface with the extracellular environment. Cancer cells have a different ‘glycan coat’ to healthy cells and aberrant glycosylation is a universal feature of cancer cells linked to all of the cancer hallmarks. This means glycans hold huge potential for the development of new diagnostic and therapeutic strategies. One key change in tumour glycosylation is increased sialylation, both on N-glycans and O-glycans, which leads to a dense forest of sialylated structures covering the cell surface. This hypersialylation has far-reaching consequences for cancer cells, and sialylated glycans are fundamental in tumour growth, metastasis, immune evasion and drug resistance. The development of strategies to inhibit aberrant sialylation in cancer represents an important opportunity to develop new therapeutics. Here, I summarise recent advances to target aberrant sialylation in cancer, including the development of sialyltransferase inhibitors and strategies to inhibit Siglecs and Selectins, and discuss opportunities for the future.
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Wielgat P, Narejko K, Car H. SARS-CoV-2 Attacks in the Brain: Focus on the Sialome. Cells 2022; 11:1458. [PMID: 35563764 PMCID: PMC9104523 DOI: 10.3390/cells11091458] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/20/2022] [Accepted: 04/24/2022] [Indexed: 12/16/2022] Open
Abstract
The epidemiological observations suggest that respiratory and gastrointestinal symptoms caused by severe acute respiratory coronavirus 2 (SARS-CoV-2) are accompanied by short- and long-term neurological manifestations. There is increasing evidence that the neuroinvasive potential of SARS-CoV-2 is closely related to its capacity to interact with cell membrane sialome. Given the wide expression of sialylated compounds of cell membranes in the brain, the interplay between cell membrane sialoglycans and the virus is crucial for its attachment and cell entry, transport, neuronal damage and brain immunity. Here, we focus on the significance of the brain sialome in the progress of coronavirus disease 2019 (COVID-19) and SARS-CoV-2-induced neuropathology.
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Affiliation(s)
- Przemyslaw Wielgat
- Department of Clinical Pharmacology, Medical University of Bialystok, Waszyngtona 15A, 15-274 Bialystok, Poland; (K.N.); (H.C.)
| | - Karolina Narejko
- Department of Clinical Pharmacology, Medical University of Bialystok, Waszyngtona 15A, 15-274 Bialystok, Poland; (K.N.); (H.C.)
| | - Halina Car
- Department of Clinical Pharmacology, Medical University of Bialystok, Waszyngtona 15A, 15-274 Bialystok, Poland; (K.N.); (H.C.)
- Department of Experimental Pharmacology, Medical University of Bialystok, Szpitalna 37, 15-265 Bialystok, Poland
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14
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Transgenic mouse models to study the physiological and pathophysiological roles of human Siglecs. Biochem Soc Trans 2022; 50:935-950. [PMID: 35383825 DOI: 10.1042/bst20211203] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/14/2022] [Accepted: 03/18/2022] [Indexed: 12/14/2022]
Abstract
Sialic acid-binding immunoglobulin-like lectins (Siglecs) are important immunomodulatory receptors. Due to differences between human and mouse Siglecs, defining the in vivo roles for human Siglecs (hSiglecs) can be challenging. One solution is the development and use of hSiglec transgenic mice to assess the physiological roles of hSiglecs in health and disease. These transgenic mice can also serve as important models for the pre-clinical testing of immunomodulatory approaches that are based on targeting hSiglecs. Four general methods have been used to create hSiglec-expressing transgenic mice, each with associated advantages and disadvantages. To date, transgenic mouse models expressing hSiglec-2 (CD22), -3 (CD33), -7, -8, -9, -11, and -16 have been created. This review focuses on both the generation of these hSiglec transgenic mice, along with the important findings that have been made through their study. Cumulatively, hSiglec transgenic mouse models are providing a deeper understanding of the differences between human and mice orthologs/paralogs, mechanisms by which Siglecs regulate immune cell signaling, physiological roles of Siglecs in disease, and different paradigms where targeting Siglecs may be therapeutically advantageous.
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15
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Thiesler H, Küçükerden M, Gretenkort L, Röckle I, Hildebrandt H. News and Views on Polysialic Acid: From Tumor Progression and Brain Development to Psychiatric Disorders, Neurodegeneration, Myelin Repair and Immunomodulation. Front Cell Dev Biol 2022; 10:871757. [PMID: 35617589 PMCID: PMC9013797 DOI: 10.3389/fcell.2022.871757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 03/08/2022] [Indexed: 12/15/2022] Open
Abstract
Polysialic acid (polySia) is a sugar homopolymer consisting of at least eight glycosidically linked sialic acid units. It is a posttranslational modification of a limited number of proteins with the neural cell adhesion molecule NCAM being the most prominent. As extensively reviewed before, polySia-NCAM is crucial for brain development and synaptic plasticity but also modulates tumor growth and malignancy. Functions of polySia have been attributed to its polyanionic character, its spatial expansion into the extracellular space, and its modulation of NCAM interactions. In this mini-review, we first summarize briefly, how the modulation of NCAM functions by polySia impacts tumor cell growth and leads to malformations during brain development of polySia-deficient mice, with a focus on how the latter may be linked to altered behaviors in the mouse model and to neurodevelopmental predispositions to psychiatric disorders. We then elaborate on the implications of polySia functions in hippocampal plasticity, learning and memory of mice in light of recently described polySia changes related to altered neurogenesis in the aging human brain and in neurodegenerative disease. Furthermore, we highlight recent progress that extends the range of polySia functions across diverse fields of neurobiology such as cortical interneuron development and connectivity, myelination and myelin repair, or the regulation of microglia activity. We discuss possible common and distinct mechanisms that may underlie these seemingly divergent roles of polySia, and provide prospects for new therapeutic approaches building on our improved understanding of polySia functions.
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16
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Villanueva-Cabello TM, Gutiérrez-Valenzuela LD, Salinas-Marín R, López-Guerrero DV, Martínez-Duncker I. Polysialic Acid in the Immune System. Front Immunol 2022; 12:823637. [PMID: 35222358 PMCID: PMC8873093 DOI: 10.3389/fimmu.2021.823637] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 12/28/2021] [Indexed: 01/01/2023] Open
Abstract
Polysialic acid (polySia) is a highly regulated polymer of sialic acid (Sia) with such potent biophysical characteristics that when expressed drastically influences the interaction properties of cells. Although much of what is known of polySia in mammals has been elucidated from the study of its role in the central nervous system (CNS), polySia is also expressed in other tissues, including the immune system where it presents dynamic changes during differentiation, maturation, and activation of different types of immune cells of the innate and adaptive response, being involved in key regulatory mechanisms. At least six polySia protein carriers (CCR7, ESL-1, NCAM, NRP2, ST8Sia 2, and ST8Sia 4) are expressed in different types of immune cells, but there is still much to be explored in regard not only to the regulatory mechanisms that determine their expression and the structure of polySia chains but also to the identification of the cis- and trans- ligands of polySia that establish signaling networks. This review summarizes the current knowledge on polySia in the immune system, addressing its biosynthesis, its tools for identification and structural characterization, and its functional roles and therapeutic implications.
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Affiliation(s)
- Tania M. Villanueva-Cabello
- Laboratorio de Glicobiología Humana y Diagnóstico Molecular, Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | - Lya D. Gutiérrez-Valenzuela
- Laboratorio de Glicobiología Humana y Diagnóstico Molecular, Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Roberta Salinas-Marín
- Laboratorio de Glicobiología Humana y Diagnóstico Molecular, Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | | | - Iván Martínez-Duncker
- Laboratorio de Glicobiología Humana y Diagnóstico Molecular, Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
- *Correspondence: Iván Martínez-Duncker,
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17
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O-Acetylation of Capsular Polysialic Acid Enables Escherichia coli K1 Escaping from Siglec-Mediated Innate Immunity and Lysosomal Degradation of E. coli-Containing Vacuoles in Macrophage-Like Cells. Microbiol Spectr 2021; 9:e0039921. [PMID: 34878295 PMCID: PMC8653822 DOI: 10.1128/spectrum.00399-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli K1 causes bacteremia and meningitis in human neonates. The K1 capsule, an α2,8-linked polysialic acid (PSA) homopolymer, is its essential virulence factor. PSA is usually partially modified by O-acetyl groups. It is known that O-acetylation alters the antigenicity of PSA, but its impact on the interactions between E. coli K1 and host cells is unclear. In this study, a phase variant was obtained by passage of E. coli K1 parent strain, which expressed a capsule with 44% O-acetylation whereas the capsule of the parent strain has only 3%. The variant strain showed significantly reduced adherence and invasion to macrophage-like cells in comparison to the parent strain. Furthermore, we found that O-acetylation of PSA enhanced the modulation of trafficking of E. coli-containing vacuoles (ECV), enabling them to avoid fusing with lysosomes in these cells. Intriguingly, by using quartz crystal microbalance, we demonstrated that the PSA purified from the parent strain interacted with human sialic acid-binding immunoglobulin-like lectins (Siglecs), including Siglec-5, Siglec-7, Siglec-11, and Siglec-14. However, O-acetylated PSA from the variant interacted much less and also suppressed the production of Siglec-mediated proinflammatory cytokines. The adherence of the parent strain to human macrophage-like cells was significantly blocked by monoclonal antibodies against Siglec-11 and Siglec-14. Furthermore, the variant strain caused increased bacteremia and higher lethality in neonatal mice compared to the parent strain. These data elucidate that O-acetylation of K1 capsule enables E. coli to escape from Siglec-mediated innate immunity and lysosomal degradation; therefore, it is a strategy used by E. coli K1 to regulate its virulence. IMPORTANCEEscherichia coli K1 is a leading cause of neonatal meningitis. The mortality and morbidity of this disease remain significantly high despite antibiotic therapy. One major limitation on advances in prevention and therapy for meningitis is an incomplete understanding of its pathogenesis. E. coli K1 is surrounded by PSA, which is observed to have high-frequency variation of O-acetyl modification. Here, we present an in-depth study of the function of O-acetylation in PSA at each stage of host-pathogen interaction. We found that a high level of O-acetylation significantly interfered with Siglec-mediated bacterial adherence to macrophage-like cells, and blunted the proinflammatory response. Furthermore, the O-acetylation of PSA modulated the trafficking of ECVs to prevent them from fusing with lysosomes, enabling them to escape degradation by lysozymes within these cells. Elucidating how subtle modification of the capsule enhances bacterial defenses against host innate immunity will enable the future development of effective drugs or vaccines against infection by E. coli K1.
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18
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Jung J, Enterina JR, Bui DT, Mozaneh F, Lin PH, Nitin, Kuo CW, Rodrigues E, Bhattacherjee A, Raeisimakiani P, Daskhan GC, St. Laurent CD, Khoo KH, Mahal LK, Zandberg WF, Huang X, Klassen JS, Macauley MS. Carbohydrate Sulfation As a Mechanism for Fine-Tuning Siglec Ligands. ACS Chem Biol 2021; 16:2673-2689. [PMID: 34661385 DOI: 10.1021/acschembio.1c00501] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The immunomodulatory family of Siglecs recognizes sialic acid-containing glycans as "self", which is exploited in cancer for immune evasion. The biochemical nature of Siglec ligands remains incompletely understood, with emerging evidence suggesting the importance of carbohydrate sulfation. Here, we investigate how specific sulfate modifications affect Siglec ligands by overexpressing eight carbohydrate sulfotransferases (CHSTs) in five cell lines. Overexpression of three CHSTs─CHST1, CHST2, or CHST4─significantly enhance the binding of numerous Siglecs. Unexpectedly, two other CHSTs (Gal3ST2 and Gal3ST3) diminish Siglec binding, suggesting a new mode to modulate Siglec ligands via sulfation. Results are cell type dependent, indicating that the context in which sulfated glycans are presented is important. Moreover, a pharmacological blockade of N- and O-glycan maturation reveals a cell-type-specific pattern of importance for either class of glycan. Production of a highly homogeneous Siglec-3 (CD33) fragment enabled a mass-spectrometry-based binding assay to determine ≥8-fold and ≥2-fold enhanced affinity for Neu5Acα2-3(6-O-sulfo)Galβ1-4GlcNAc and Neu5Acα2-3Galβ1-4(6-O-sulfo)GlcNAc, respectively, over Neu5Acα2-3Galβ1-4GlcNAc. CD33 shows significant additivity in affinity (≥28-fold) for the disulfated ligand, Neu5Acα2-3(6-O-sulfo)Galβ1-4(6-O-sulfo)GlcNAc. Moreover, joint overexpression of CHST1 with CHST2 in cells greatly enhanced the binding of CD33 and several other Siglecs. Finally, we reveal that CHST1 is upregulated in numerous cancers, correlating with poorer survival rates and sodium chlorate sensitivity for the binding of Siglecs to cancer cell lines. These results provide new insights into carbohydrate sulfation as a general mechanism for tuning Siglec ligands on cells, including in cancer.
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Affiliation(s)
- Jaesoo Jung
- Department of Chemistry, University of Alberta, Edmonton, T6G 2G2, Canada
| | - Jhon R. Enterina
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, T6G 2J7, Canada
| | - Duong T. Bui
- Department of Chemistry, University of Alberta, Edmonton, T6G 2G2, Canada
| | - Fahima Mozaneh
- Department of Chemistry, University of Alberta, Edmonton, T6G 2G2, Canada
| | - Po-Han Lin
- Departments of Chemistry and Biomedical Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - Nitin
- Department of Chemistry, The University of British Columbia, Kelowna, V1V 1V7, Canada
| | - Chu-Wei Kuo
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Emily Rodrigues
- Department of Chemistry, University of Alberta, Edmonton, T6G 2G2, Canada
| | | | | | - Gour C. Daskhan
- Department of Chemistry, University of Alberta, Edmonton, T6G 2G2, Canada
| | | | - Kay-Hooi Khoo
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Lara K. Mahal
- Department of Chemistry, University of Alberta, Edmonton, T6G 2G2, Canada
| | - Wesley F. Zandberg
- Department of Chemistry, The University of British Columbia, Kelowna, V1V 1V7, Canada
| | - Xuefei Huang
- Departments of Chemistry and Biomedical Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - John S. Klassen
- Department of Chemistry, University of Alberta, Edmonton, T6G 2G2, Canada
| | - Matthew S. Macauley
- Department of Chemistry, University of Alberta, Edmonton, T6G 2G2, Canada
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, T6G 2J7, Canada
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19
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Abstract
The surface of every eukaryotic cell is coated in a dense layer of structurally diverse glycans that together comprise the glycocalyx, a key interface between intracellular biochemistry and the external environment. Many of the glycans within the glycocalyx terminate in anionic monosaccharides belonging to the sialic acid family. Advances in our understanding of the biological processes mediated by sialic acids at the interfaces between cells have catalyzed interest in metabolic, enzymatic, and chemical strategies to edit the total complement of cellular sialic acids-the sialome. Here, we review strategies for altering the composition of the sialome with particular focus on glycan structures and state-of-the-art tools.
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Affiliation(s)
- Landon J. Edgar
- Department of Pharmacology and Toxicology, The University of Toronto, Toronto, Ontario, Canada, M5S 1A8
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20
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Jong H, Wösten MMSM, Wennekes T. Sweet impersonators: Molecular mimicry of host glycans by bacteria. Glycobiology 2021; 32:11-22. [PMID: 34939094 PMCID: PMC8881735 DOI: 10.1093/glycob/cwab104] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/03/2021] [Accepted: 09/28/2021] [Indexed: 12/02/2022] Open
Abstract
All bacteria display surface-exposed glycans that can play an important role in their interaction with the host and in select cases mimic the glycans found on host cells, an event called molecular or glycan mimicry. In this review, we highlight the key bacteria that display human glycan mimicry and provide an overview of the involved glycan structures. We also discuss the general trends and outstanding questions associated with human glycan mimicry by bacteria. Finally, we provide an overview of several techniques that have emerged from the discipline of chemical glycobiology, which can aid in the study of the composition, variability, interaction and functional role of these mimicking glycans.
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Affiliation(s)
- Hanna Jong
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomedical Research, Utrecht University, Utrecht, The Netherlands.,Department of Biomolecular Health Sciences, Utrecht University, Utrecht, The Netherlands
| | - Marc M S M Wösten
- Department of Biomolecular Health Sciences, Utrecht University, Utrecht, The Netherlands
| | - Tom Wennekes
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomedical Research, Utrecht University, Utrecht, The Netherlands
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21
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Salminen A, Kaarniranta K, Kauppinen A. Hypoxia/ischemia impairs CD33 (Siglec-3)/TREM2 signaling: Potential role in Alzheimer's pathogenesis. Neurochem Int 2021; 150:105186. [PMID: 34530055 DOI: 10.1016/j.neuint.2021.105186] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/10/2021] [Accepted: 09/12/2021] [Indexed: 12/22/2022]
Abstract
Recent genetic and molecular studies have indicated that the innate immune system, especially microglia, have a crucial role in the accumulation of β-amyloid plaques in Alzheimer's disease (AD). In particular, the CD33 receptor, also called Siglec-3, inhibits the TREM2 receptor-induced phagocytic activity of microglia. CD33 receptors recognize the α2,3 and α2,6-linked sialic groups in tissue glycocalyx, especially sialylated gangliosides in human brain. The CD33 receptor triggers cell-type specific responses, e.g., in microglia, CD33 inhibits phagocytosis, whereas in natural killer cells, it inhibits the cytotoxic activity of the NKG2D receptor. Nonetheless, the regulation of the activity of CD33 receptor needs to be clarified. For example, it seems that hypoxia/ischemia, a potential cause of AD pathology, increases the expression of CD33 and its downstream target SHP-1, a tyrosine phosphatase which suppresses the phagocytosis driven by TREM2. Moreover, hypoxia/ischemia increases the deposition of sialylated gangliosides, e.g., GM1, GM2, GM3, and GD1, which are ligands for inhibitory CD33/Siglec-3 receptors. In addition, β-amyloid peptides bind to the sialylated gangliosides in raft-like clusters and subsequently these gangliosides act as seeds for the formation of β-amyloid plaques in AD pathology. It is known that senile plaques contain sialylated GM1, GM2, and GM3 gangliosides, i.e., the same species induced by hypoxia/ischemia treatment. Sialylated gangliosides in plaques might stimulate the CD33/Siglec-3 receptors of microglia and thus impede TREM2-driven phagocytosis. We propose that hypoxia/ischemia, e.g., via the accumulation of sialylated gangliosides, prevents the phagocytosis of β-amyloid deposits by inhibiting CD33/TREM2 signaling.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland.
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 100, FI-70029, KYS, Finland
| | - Anu Kauppinen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland
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22
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Khan N, de Manuel M, Peyregne S, Do R, Prufer K, Marques-Bonet T, Varki N, Gagneux P, Varki A. Multiple Genomic Events Altering Hominin SIGLEC Biology and Innate Immunity Predated the Common Ancestor of Humans and Archaic Hominins. Genome Biol Evol 2021; 12:1040-1050. [PMID: 32556248 PMCID: PMC7379906 DOI: 10.1093/gbe/evaa125] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2020] [Indexed: 12/11/2022] Open
Abstract
Human-specific pseudogenization of the CMAH gene eliminated the mammalian sialic acid (Sia) Neu5Gc (generating an excess of its precursor Neu5Ac), thus changing ubiquitous cell surface “self-associated molecular patterns” that modulate innate immunity via engagement of CD33-related-Siglec receptors. The Alu-fusion-mediated loss-of-function of CMAH fixed ∼2–3 Ma, possibly contributing to the origins of the genus Homo. The mutation likely altered human self-associated molecular patterns, triggering multiple events, including emergence of human-adapted pathogens with strong preference for Neu5Ac recognition and/or presenting Neu5Ac-containing molecular mimics of human glycans, which can suppress immune responses via CD33-related-Siglec engagement. Human-specific alterations reported in some gene-encoding Sia-sensing proteins suggested a “hotspot” in hominin evolution. The availability of more hominid genomes including those of two extinct hominins now allows full reanalysis and evolutionary timing. Functional changes occur in 8/13 members of the human genomic cluster encoding CD33-related Siglecs, all predating the human common ancestor. Comparisons with great ape genomes indicate that these changes are unique to hominins. We found no evidence for strong selection after the Human–Neanderthal/Denisovan common ancestor, and these extinct hominin genomes include almost all major changes found in humans, indicating that these changes in hominin sialobiology predate the Neanderthal–human divergence ∼0.6 Ma. Multiple changes in this genomic cluster may also explain human-specific expression of CD33rSiglecs in unexpected locations such as amnion, placental trophoblast, pancreatic islets, ovarian fibroblasts, microglia, Natural Killer(NK) cells, and epithelia. Taken together, our data suggest that innate immune interactions with pathogens markedly altered hominin Siglec biology between 0.6 and 2 Ma, potentially affecting human evolution.
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Affiliation(s)
- Naazneen Khan
- Glycobiology Research and Training Center, Department of Medicine, University of California San Diego.,Center for Academic Research and Training in Anthropogeny (CARTA),University of California San Diego
| | - Marc de Manuel
- Institute of Evolutionary Biology (UPF-CSIC), PRBB, Barcelona, Spain
| | - Stephane Peyregne
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Raymond Do
- Glycobiology Research and Training Center, Department of Medicine, University of California San Diego.,Center for Academic Research and Training in Anthropogeny (CARTA),University of California San Diego
| | - Kay Prufer
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Tomas Marques-Bonet
- Institute of Evolutionary Biology (UPF-CSIC), PRBB, Barcelona, Spain.,Catalan Institution of Research and Advanced Studies (ICREA), Barcelona, Spain.,CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.,Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, Barcelona, Spain
| | - Nissi Varki
- Glycobiology Research and Training Center, Department of Medicine, University of California San Diego.,Center for Academic Research and Training in Anthropogeny (CARTA),University of California San Diego
| | - Pascal Gagneux
- Glycobiology Research and Training Center, Department of Medicine, University of California San Diego.,Center for Academic Research and Training in Anthropogeny (CARTA),University of California San Diego
| | - Ajit Varki
- Glycobiology Research and Training Center, Department of Medicine, University of California San Diego.,Center for Academic Research and Training in Anthropogeny (CARTA),University of California San Diego
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23
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Functions and therapeutic targets of Siglec-mediated infections, inflammations and cancers. J Formos Med Assoc 2021; 120:5-24. [DOI: 10.1016/j.jfma.2019.10.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 06/11/2019] [Accepted: 10/28/2019] [Indexed: 12/20/2022] Open
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24
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Klaus C, Liao H, Allendorf DH, Brown GC, Neumann H. Sialylation acts as a checkpoint for innate immune responses in the central nervous system. Glia 2020; 69:1619-1636. [PMID: 33340149 DOI: 10.1002/glia.23945] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/23/2020] [Accepted: 11/26/2020] [Indexed: 12/28/2022]
Abstract
Sialic acids are monosaccharides that normally terminate the glycan chains of cell surface glyco-proteins and -lipids in mammals, and are highly enriched in the central nervous tissue. Sialic acids are conjugated to proteins and lipids (termed "sialylation") by specific sialyltransferases, and are removed ("desialylation") by neuraminidases. Cell surface sialic acids are sensed by complement factor H (FH) to inhibit complement activation or by sialic acid-binding immunoglobulin-like lectin (SIGLEC) receptors to inhibit microglial activation, phagocytosis, and oxidative burst. In contrast, desialylation of cells enables binding of the opsonins C1, calreticulin, galectin-3, and collectins, stimulating phagocytosis of such cells. Hypersialylation is used by bacteria and cancers as camouflage to escape immune recognition, while polysialylation of neurons protects synapses and neurogenesis. Insufficient lysosomal cleavage of sialylated molecules can lead to lysosomal accumulation of lipids and aggregated proteins, which if excessive may be expelled into the extracellular space. On the other hand, desialylation of immune receptors can activate them or trigger removal of proteins. Loss of inhibitory SIGLECs or FH triggers reduced clearance of aggregates, oxidative brain damage and complement-mediated retinal damage. Thus, cell surface sialylation recognized by FH, SIGLEC, and other immune-related receptors acts as a major checkpoint inhibitor of innate immune responses in the central nervous system, while excessive cleavage of sialic acid residues and consequently removing this checkpoint inhibitor may trigger lipid accumulation, protein aggregation, inflammation, and neurodegeneration.
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Affiliation(s)
- Christine Klaus
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Huan Liao
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | | | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Harald Neumann
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
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25
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Läubli H, Kawanishi K, George Vazhappilly C, Matar R, Merheb M, Sarwar Siddiqui S. Tools to study and target the Siglec-sialic acid axis in cancer. FEBS J 2020; 288:6206-6225. [PMID: 33251699 DOI: 10.1111/febs.15647] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/18/2020] [Accepted: 11/23/2020] [Indexed: 12/16/2022]
Abstract
Siglecs are widely expressed on leucocytes and bind to ubiquitously presented glycans containing sialic acids (sialoglycans). Most Siglecs carry an immunoreceptor tyrosine-based inhibition motif (ITIM) and elicit an inhibitory intracellular signal upon ligand binding. A few Siglec receptors can, however, recruit immunoreceptor tyrosine-based activation motif (ITAM)-containing factors, which activate cells. The role of hypersialylation (the enhanced expression of sialoglycans) has recently been explored in cancer progression. Mechanistic studies have shown that hypersialylation on cancer cells can engage inhibitory Siglecs on the surface of immune cells and induce immunosuppression. These recent studies strongly suggest that the Siglec-sialic acid axis can act as a potential target for cancer immunotherapy. Moreover, the use of new tools and techniques is facilitating these studies. In this review, we summarise techniques used to study Siglecs, including different mouse models, monoclonal antibodies, Siglec fusion proteins, and sialoglycan arrays. Furthermore, we discuss the recent major developments in the study of Siglecs in cancer immunosuppression, tools, and techniques used in targeting the Siglec-sialic acid axis and the possibility of clinical intervention.
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Affiliation(s)
- Heinz Läubli
- Laboratory for Cancer Immunotherapy, Department of Biomedicine, and Medical Oncology, Department of Internal Medicine, University Hospital Basel, Switzerland
| | - Kunio Kawanishi
- Kidney and Vascular Pathology, University of Tsukuba, Ibaraki, Japan
| | | | - Rachel Matar
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), UAE
| | - Maxime Merheb
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), UAE
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Hane M, Chen DY, Varki A. Human-specific microglial Siglec-11 transcript variant has the potential to affect polysialic acid-mediated brain functions at a distance. Glycobiology 2020; 31:231-242. [PMID: 32845322 DOI: 10.1093/glycob/cwaa082] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 08/05/2020] [Accepted: 08/07/2020] [Indexed: 12/11/2022] Open
Abstract
CD33-related Siglecs are often found on innate immune cells and modulate their reactivity by recognition of sialic acid-based "self-associated molecular patterns" and signaling via intracellular tyrosine-based cytosolic motifs. Previous studies have shown that Siglec-11 specifically binds to the brain-enriched polysialic acid (polySia/PSA) and that its microglial expression in the brain is unique to humans. Furthermore, human microglial Siglec-11 exists as an alternate splice form missing the exon encoding the last (fifth) Ig-like C2-set domain of the extracellular portion of the protein, but little is known about the functional consequences of this variation. Here, we report that the recombinant soluble human microglial form of Siglec-11 (hSiglec-11(4D)-Fc) binds endogenous and immobilized polySia better than the tissue macrophage form (hSiglec-11(5D)-Fc) or the chimpanzee form (cSiglec-11(5D)-Fc). The Siglec-11 protein is also prone to aggregation, potentially influencing its ligand-binding ability. Additionally, Siglec-11 protein can be secreted in both intact and proteolytically cleaved forms. The microglial splice variant has reduced proteolytic release and enhanced incorporation into exosomes, a process that appears to be regulated by palmitoylation of cysteines in the cytosolic tail. Taken together, these data demonstrate that human brain specific microglial hSiglec-11(4D) has different molecular properties and can be released on exosomes and/or as proteolytic products, with the potential to affect polySia-mediated brain functions at a distance.
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Affiliation(s)
- Masaya Hane
- Departments of Medicine and Cellular & Molecular Medicine, Center for Academic Research and Training in Anthropogeny, Glycobiology Research and Training Center, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
| | - Dillon Y Chen
- Departments of Medicine and Cellular & Molecular Medicine, Center for Academic Research and Training in Anthropogeny, Glycobiology Research and Training Center, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
| | - Ajit Varki
- Departments of Medicine and Cellular & Molecular Medicine, Center for Academic Research and Training in Anthropogeny, Glycobiology Research and Training Center, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
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Siddiqui SS, Rahman S, Rupasinghe HV, Vazhappilly CG. Dietary Flavonoids in p53-Mediated Immune Dysfunctions Linking to Cancer Prevention. Biomedicines 2020; 8:biomedicines8080286. [PMID: 32823757 PMCID: PMC7460013 DOI: 10.3390/biomedicines8080286] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/03/2020] [Accepted: 08/11/2020] [Indexed: 12/14/2022] Open
Abstract
The p53 protein plays a central role in mediating immune functioning and determines the fate of the cells. Its role as a tumor suppressor, and in transcriptional regulation and cytokine activity under stress conditions, is well defined. The wild type (WT) p53 functions as a guardian for the genome, while the mutant p53 has oncogenic roles. One of the ways that p53 combats carcinogenesis is by reducing inflammation. WT p53 functions as an anti-inflammatory molecule via cross-talk activity with multiple immunological pathways, such as the major histocompatibility complex I (MHCI) associated pathway, toll-like receptors (TLRs), and immune checkpoints. Due to the multifarious roles of p53 in cancer, it is a potent target for cancer immunotherapy. Plant flavonoids have been gaining recognition over the last two decades to use as a potential therapeutic regimen in ameliorating diseases. Recent studies have shown the ability of flavonoids to suppress chronic inflammation, specifically by modulating p53 responses. Further, the anti-oxidant Keap1/Nrf2/ARE pathway could play a crucial role in mitigating oxidative stress, leading to a reduction of chronic inflammation linked to the prevention of cancer. This review aims to discuss the pharmacological properties of plant flavonoids in response to various oxidative stresses and immune dysfunctions and analyzes the cross-talk between flavonoid-rich dietary intake for potential disease prevention.
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Affiliation(s)
- Shoib Sarwar Siddiqui
- Department of Biotechnology, American University of Ras Al Khaimah, Ras Al Khaimah PO Box 10021, UAE;
| | - Sofia Rahman
- School of Natural Sciences and Mathematics, The University of Texas at Dallas, Richardson, TX 75080, USA;
| | - H.P. Vasantha Rupasinghe
- Department of Plant, Food, and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, NS B2N 5E3, Canada;
- Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Cijo George Vazhappilly
- Department of Biotechnology, American University of Ras Al Khaimah, Ras Al Khaimah PO Box 10021, UAE;
- Correspondence:
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Liao H, Klaus C, Neumann H. Control of Innate Immunity by Sialic Acids in the Nervous Tissue. Int J Mol Sci 2020; 21:ijms21155494. [PMID: 32752058 PMCID: PMC7432451 DOI: 10.3390/ijms21155494] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 12/11/2022] Open
Abstract
Sialic acids (Sias) are the most abundant terminal sugar residues of glycoproteins and glycolipids on the surface of mammalian cells. The nervous tissue is the organ with the highest expression level of Sias. The ‘sialylation’ of glycoconjugates is performed via sialyltransferases, whereas ‘desialylation’ is done by sialidases or is a possible consequence of oxidative damage. Sialic acid residues on the neural cell surfaces inhibit complement and microglial activation, as well as phagocytosis of the underlying structures, via binding to (i) complement factor H (CFH) or (ii) sialic acid-binding immunoglobulin-like lectin (SIGLEC) receptors. In contrast, activated microglial cells show sialidase activity that desialylates both microglia and neurons, and further stimulates innate immunity via microglia and complement activation. The desialylation conveys neurons to become susceptible to phagocytosis, as well as triggers a microglial phagocytosis-associated oxidative burst and inflammation. Dysfunctions of the ‘Sia–SIGLEC’ and/or ‘Sia–complement’ axes often lead to neurological diseases. Thus, Sias on glycoconjugates of the intact glycocalyx and its desialylation are major regulators of neuroinflammation.
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Affiliation(s)
| | | | - Harald Neumann
- Correspondence: ; Tel.: +49-228-6885-500; Fax: +49-228-6885-501
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Polysialic acid and Siglec-E orchestrate negative feedback regulation of microglia activation. Cell Mol Life Sci 2020; 78:1637-1653. [PMID: 32725371 PMCID: PMC7904730 DOI: 10.1007/s00018-020-03601-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 06/23/2020] [Accepted: 07/17/2020] [Indexed: 11/09/2022]
Abstract
Polysialic acid (polySia) emerges as a novel regulator of microglia activity. We recently identified polysialylated proteins in the Golgi compartment of murine microglia that are released in response to inflammatory stimulation. Since exogenously added polySia is able to attenuate the inflammatory response, we proposed that the release of polysialylated proteins constitutes a mechanism for negative feedback regulation of microglia activation. Here, we demonstrate that translocation of polySia from the Golgi to the cell surface can be induced by calcium depletion of the Golgi compartment and that polysialylated proteins are continuously released for at least 24 h after the onset of inflammatory stimulation. The latter was unexpected, because polySia signals detected by immunocytochemistry are rapidly depleted. However, it indicates that the amount of released polySia is much higher than anticipated based on immunostaining. This may be crucial for microglial responses during traumatic brain injury (TBI), as we detected polySia signals in activated microglia around a stab wound in the adult mouse brain. In BV2 microglia, the putative polySia receptor Siglec-E is internalized during lipopolysaccharide (LPS)-induced activation and in response to polySia exposure, indicating interaction. Correspondingly, CRISPR/Cas9-mediated Siglec-E knockout prevents inhibition of pro inflammatory activation by exogenously added polySia and leads to a strong increase of the LPS response. A comparable increase of LPS-induced activation has been observed in microglia with abolished polySia synthesis. Together, these results indicate that the release of the microglia-intrinsic polySia pool, as implicated in TBI, inhibits the inflammatory response by acting as a trans-activating ligand of Siglec-E.
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Sakamoto Y, Yoshio S, Doi H, Kawai H, Shimagaki T, Mori T, Matsuda M, Aoki Y, Osawa Y, Yoshida Y, Arai T, Itokawa N, Ito T, Seko Y, Yamaguchi K, Itoh Y, Mise Y, Saiura A, Taketomi A, Kanto T. Serum soluble sialic acid-binding immunoglobulin-like lectin-7 concentration as an indicator of liver macrophage activation and advanced fibrosis in patients with non-alcoholic fatty liver disease. Hepatol Res 2020; 50:466-477. [PMID: 31808236 DOI: 10.1111/hepr.13464] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 10/19/2019] [Accepted: 11/07/2019] [Indexed: 02/08/2023]
Abstract
AIM Non-alcoholic fatty liver disease (NAFLD) is a leading cause of liver disease worldwide. Because liver fibrosis is associated with the long-term prognosis of patients with NAFLD, there is an urgent need for non-invasive markers of liver fibrosis. Sialic acid-binding immunoglobulin-like lectin-7 (Siglec-7) is an immunomodulatory molecule expressed on various immune cells, including macrophages, which plays a key role in liver inflammation and fibrosis in NAFLD. We aimed to determine whether serum levels of soluble Siglec-7 (sSiglec-7) could have utility at a marker of fibrosis in this patient population. METHODS We examined serum samples from 93 NAFLD patients and 19 healthy donors for macrophage-associated protein, including sSiglec-7, soluble CD163, and YKL-40, and examined their correlation with liver fibrosis scores, tissue elastography, and histological findings. Independent factors associated with advanced fibrosis were analyzed using a logistic regression model and a decision tree. To clarify the source of sSiglec-7, we examined its expression in liver tissue-derived macrophages and cultured monocyte-derived macrophages. RESULTS Serum sSiglec-7 levels were significantly higher in NAFLD patients compared with healthy donors, and correlated positively with sCD163 and YKL-40 levels. Serum sSiglec-7 was an independent diagnostic marker with high specificity (96.3%) for advanced fibrosis (F3 and F4) in NAFLD patients. Siglec-7 was mainly expressed on CCR2+ macrophages in the liver, and sSiglec-7 production by monocyte-derived macrophages in vitro was increased after stimulation by pro-inflammatory factors. CONCLUSIONS Elevated serum sSiglec-7 could serve as an independent marker with high specificity for advanced liver fibrosis in patients with NAFLD.
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Affiliation(s)
- Yuzuru Sakamoto
- The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Japan.,Department of Gastoenterological Surgery I, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Sachiyo Yoshio
- The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Japan
| | - Hiroyoshi Doi
- The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Japan
| | - Hironari Kawai
- The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Japan
| | - Tomonari Shimagaki
- The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Japan
| | - Taizo Mori
- The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Japan
| | - Michitaka Matsuda
- The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Japan
| | - Yoshihiko Aoki
- The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Japan
| | - Yosuke Osawa
- The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Japan
| | - Yuji Yoshida
- Department of Internal Medicine, Division of Gastroenterology, Nippon Medical School Chiba Hokusoh Hospital, Inzai, Japan
| | - Taeang Arai
- Department of Internal Medicine, Division of Gastroenterology, Nippon Medical School Chiba Hokusoh Hospital, Inzai, Japan
| | - Norio Itokawa
- Department of Internal Medicine, Division of Gastroenterology, Nippon Medical School Chiba Hokusoh Hospital, Inzai, Japan
| | - Takanori Ito
- Division of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yuya Seko
- Division of Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Kanji Yamaguchi
- Division of Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yoshihito Itoh
- Division of Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yoshihiro Mise
- Department of Hepato-Pancreatic-Biliary Surgery, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Akio Saiura
- Department of Hepato-Pancreatic-Biliary Surgery, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Akinobu Taketomi
- Department of Gastoenterological Surgery I, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Tatsuya Kanto
- The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Japan
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van de Wall S, Santegoets KC, van Houtum EJ, Büll C, Adema GJ. Sialoglycans and Siglecs Can Shape the Tumor Immune Microenvironment. Trends Immunol 2020; 41:274-285. [DOI: 10.1016/j.it.2020.02.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 01/30/2020] [Accepted: 02/05/2020] [Indexed: 12/23/2022]
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Angata T. Siglecs that Associate with DAP12. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1204:215-230. [PMID: 32152949 DOI: 10.1007/978-981-15-1580-4_9] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Siglecs are a family of transmembrane receptor-like glycan-recognition proteins expressed primarily on leukocytes. Majority of Siglecs have an intracellular sequence motif called immunoreceptor tyrosine-based inhibitory motif (ITIM) and associate with Src homology region 2 domain-containing tyrosine phosphatase-1 (SHP-1), and negatively regulate tyrosine phosphorylation-mediated intracellular signaling events. On the other hand, some Siglecs have a positively charged amino acid residue in the transmembrane domain and associate with DNAX activation protein of 12 kDa (DAP12), which in turn recruits spleen tyrosine kinase (Syk). These DAP12-associated Siglecs play diverse functions. For example, Siglec-15 is conserved throughout vertebrate evolution and plays a role in bone homeostasis by regulating osteoclast development and function. Human Siglec-14 and -16 have inhibitory counterparts (Siglec-5 and -11, respectively), which show extremely high sequence similarity with them at the extracellular domain but interact with SHP-1. The DAP12-associated Siglec in such "paired receptor" configuration counteracts the pathogens that exploit the inhibitory counterpart. Polymorphisms (mutations) that render DAP12-associated inactive Siglecs are found in humans, and some of these appear to be associated with sensitivity or resistance of human hosts to bacterially induced conditions. Studies of mouse Siglec-H have revealed complex and intriguing functions it plays in regulating adaptive immunity. Many questions remain unanswered, and further molecular and genetic studies of DAP12-associated Siglecs will yield valuable insights with translational relevance.
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Affiliation(s)
- Takashi Angata
- Institute of Biological Chemistry, Academia Sinica, 128, Section 2, Academia Road, Nangang District, Taipei, Taiwan.
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33
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Abstract
Siglecs are sialic acid (Sia) recognizing immunoglobulin-like receptors expressed on the surface of all the major leukocyte lineages in mammals. Siglecs recognize ubiquitous Sia epitopes on various glycoconjugates in the cell glycocalyx and transduce signals to regulate immunological and inflammatory activities of these cells. The subset known as CD33-related Siglecs is principally inhibitory receptors that suppress leukocyte activation, and recent research has shown that a number of bacterial pathogens use Sia mimicry to engage these Siglecs as an immune evasion strategy. Conversely, Siglec-1 is a macrophage phagocytic receptor that engages GBS and other sialylated bacteria to promote effective phagocytosis and antigen presentation for the adaptive immune response, whereas certain viruses and parasites use Siglec-1 to gain entry to immune cells as a proximal step in the infectious process. Siglecs are positioned in crosstalk with other host innate immune sensing pathways to modulate the immune response to infection in complex ways. This chapter summarizes the current understanding of Siglecs at the host-pathogen interface, a field of study expanding in breadth and medical importance, and which provides potential targets for immune-based anti-infective strategies.
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Affiliation(s)
- Yung-Chi Chang
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, No. 1, Sec. 1, Jen-Ai Rd., Taipei, 10051, Taiwan.
| | - Victor Nizet
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, and Skaggs School of Pharmacy and Pharmaceutical Sciences, UC San Diego, 9500 Gilman Drive Mail Code 0760, La Jolla, CA, 92093, USA
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Läubli H, Varki A. Sialic acid-binding immunoglobulin-like lectins (Siglecs) detect self-associated molecular patterns to regulate immune responses. Cell Mol Life Sci 2020; 77:593-605. [PMID: 31485715 PMCID: PMC7942692 DOI: 10.1007/s00018-019-03288-x] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/11/2019] [Accepted: 08/28/2019] [Indexed: 12/12/2022]
Abstract
The mammalian immune system evolved to tightly regulate the elimination of pathogenic microbes and neoplastic transformed cells while tolerating our own healthy cells. Here, we summarize experimental evidence for the role of Siglecs-in particular CD33-related Siglecs-as self-receptors and their sialoglycan ligands in regulating this balance between recognition of self and non-self. Sialoglycans are found in the glycocalyx and extracellular fluids and matrices of all mammalian cells and can be considered as self-associated molecular patterns (SAMPs). We also provide an overview of the known interactions of Siglec receptors and sialoglycan-SAMPs. Manipulation of the Siglec-SAMP axis offers new therapeutic opportunities for the treatment of inflammatory conditions, autoimmune diseases and also cancer immunotherapy.
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Affiliation(s)
- Heinz Läubli
- Laboratory for Cancer Immunotherapy, University Hospital Basel, Petersgraben 4, 4031, Basel, Switzerland.
| | - Ajit Varki
- Department of Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, CA, 92093-0687, USA.
- Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, CA, 92093-0687, USA.
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Abstract
Sialic acid-binding immunoglobulin-type lectins (Siglecs) are expressed on the majority of white blood cells of the immune system and play critical roles in immune cell signaling. Through recognition of sialic acid-containing glycans as ligands, they help the immune system distinguish between self and nonself. Because of their restricted cell type expression and roles as checkpoints in immune cell responses in human diseases such as cancer, asthma, allergy, neurodegeneration, and autoimmune diseases they have gained attention as targets for therapeutic interventions. In this review we describe the Siglec family, its roles in regulation of immune cell signaling, current efforts to define its roles in disease processes, and approaches to target Siglecs for treatment of human disease.
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Affiliation(s)
- Shiteng Duan
- Departments of Molecular Medicine, and Immunology and Microbiology, Scripps Research, La Jolla, California 92037, USA;
| | - James C Paulson
- Departments of Molecular Medicine, and Immunology and Microbiology, Scripps Research, La Jolla, California 92037, USA;
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36
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Angata T. Siglec-15: a potential regulator of osteoporosis, cancer, and infectious diseases. J Biomed Sci 2020; 27:10. [PMID: 31900164 PMCID: PMC6941304 DOI: 10.1186/s12929-019-0610-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/19/2019] [Indexed: 12/13/2022] Open
Abstract
Siglec-15 is a member of the Siglec family of glycan-recognition proteins, primarily expressed on a subset of myeloid cells. Siglec-15 has been known to be involved in osteoclast differentiation, and is considered to be a potential therapeutic target for osteoporosis. Recent studies revealed unexpected roles of Siglec-15 in microbial infection and the cancer microenvironment, expanding the potential pathophysiological roles of Siglec-15. Chemical biology has advanced our understanding of the nature of Siglec-15 ligands, but the exact nature of Siglec-15 ligand depends on the biological context, leaving plenty of room for further exploration.
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Affiliation(s)
- Takashi Angata
- Institute of Biological Chemistry, Academia Sinica, 128, Section 2, Academia Road, Nankang District, Taipei, Taiwan.
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37
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Movsisyan LD, Macauley MS. Structural advances of Siglecs: insight into synthetic glycan ligands for immunomodulation. Org Biomol Chem 2020; 18:5784-5797. [PMID: 32756649 DOI: 10.1039/d0ob01116a] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Sialic acid-binding immunoglobulin-like lectins (Siglecs) are transmembrane proteins of the immunoglobulin (Ig) superfamily predominantly expressed on the cells of our immune system. Siglecs recognize sialic acid via their terminal V-set domain. In mammals, sialic acid-terminated glycolipids and glycoproteins are the ligands of Siglecs, and the monomeric affinity of Siglecs for their sialic acid-containing ligands is weak. Significant efforts have been devoted toward the development of chemically modified sialoside ligands to target Siglecs with higher affinity and selectivity. In this review we discuss natural and synthetic sialoside ligands for each human Siglec, emphasizing the ligand binding determinants uncovered from recent advances in protein structural information. Potential therapeutic applications of these ligands are also discussed.
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Affiliation(s)
- Levon D Movsisyan
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Matthew S Macauley
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada and Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada.
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Bärenwaldt A, Läubli H. The sialoglycan-Siglec glyco-immune checkpoint - a target for improving innate and adaptive anti-cancer immunity. Expert Opin Ther Targets 2019; 23:839-853. [PMID: 31524529 DOI: 10.1080/14728222.2019.1667977] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Introduction: During cancer progression, tumor cells develop several mechanisms to prevent killing and to shape the immune system into a tumor-promoting environment. One of such regulatory mechanism is the overexpression of sialic acid (Sia) on carbohydrates of proteins and lipids on tumor cells. Sia-containing glycans or sialoglycans were shown to inhibit immune effector functions of NK cells and T cells by engaging inhibitory Siglec receptors on the surface of these cells. They can also modulate the differentiation of myeloid cells into tumor-promoting M2 macrophages. Areas covered: We review the role of sialoglycans in cancer and introduce the Siglecs, their expression on different immune cells and their interaction with cancer-associated sialoglycans. The targeting of this sialoglycan-Siglec glyco-immune checkpoint is discussed along with potential therapeutic approaches. Pubmed was searched for publications on Siglecs, sialic acid, and cancer. Expert opinion: The targeting of sialoglycan-Siglec interactions has become a major focus in cancer research. New approaches have been developed that directly target sialic acids in tumor lesions. Targeted sialidases that cleave sialic acid specifically in the tumor, have already shown efficacy; efforts targeting the sialoglycan-Siglec pathway for improvement of CAR T cell therapy are ongoing. The sialoglycan-Siglec immune checkpoint is a promising new target for cancer immunotherapy.
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Affiliation(s)
- Anne Bärenwaldt
- Division of Medical Oncology, and Laboratory for Cancer Immunotherapy, Department of Biomedicine, University Hospital Basel , Basel , Switzerland
| | - Heinz Läubli
- Division of Medical Oncology, and Laboratory for Cancer Immunotherapy, Department of Biomedicine, University Hospital Basel , Basel , Switzerland
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39
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Siddiqui SS, Matar R, Merheb M, Hodeify R, Vazhappilly CG, Marton J, Shamsuddin SA, Al Zouabi H. Siglecs in Brain Function and Neurological Disorders. Cells 2019; 8:E1125. [PMID: 31546700 PMCID: PMC6829431 DOI: 10.3390/cells8101125] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/19/2019] [Accepted: 09/20/2019] [Indexed: 12/14/2022] Open
Abstract
Siglecs (Sialic acid-binding immunoglobulin-type lectins) are a I-type lectin that typically binds sialic acid. Siglecs are predominantly expressed in immune cells and generate activating or inhibitory signals. They are also shown to be expressed on the surface of cells in the nervous system and have been shown to play central roles in neuroinflammation. There has been a plethora of reviews outlining the studies pertaining to Siglecs in immune cells. However, this review aims to compile the articles on the role of Siglecs in brain function and neurological disorders. In humans, the most abundant Siglecs are CD33 (Siglec-3), Siglec-4 (myelin-associated glycoprotein/MAG), and Siglec-11, Whereas in mice the most abundant are Siglec-1 (sialoadhesin), Siglec-2 (CD22), Siglec-E, Siglec-F, and Siglec-H. This review is divided into three parts. Firstly, we discuss the general biological aspects of Siglecs that are expressed in nervous tissue. Secondly, we discuss about the role of Siglecs in brain function and molecular mechanism for their function. Finally, we collate the available information on Siglecs and neurological disorders. It is intriguing to study this family of proteins in neurological disorders because they carry immunoinhibitory and immunoactivating motifs that can be vital in neuroinflammation.
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Affiliation(s)
- Shoib Sarwar Siddiqui
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), Ras Al Khaimah 10021, UAE.
| | - Rachel Matar
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), Ras Al Khaimah 10021, UAE.
| | - Maxime Merheb
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), Ras Al Khaimah 10021, UAE.
| | - Rawad Hodeify
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), Ras Al Khaimah 10021, UAE.
| | - Cijo George Vazhappilly
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), Ras Al Khaimah 10021, UAE.
| | - John Marton
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), Ras Al Khaimah 10021, UAE.
| | | | - Hussain Al Zouabi
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), Ras Al Khaimah 10021, UAE.
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Akhtar-Schäfer I, Wang L, Krohne TU, Xu H, Langmann T. Modulation of three key innate immune pathways for the most common retinal degenerative diseases. EMBO Mol Med 2019; 10:emmm.201708259. [PMID: 30224384 PMCID: PMC6180304 DOI: 10.15252/emmm.201708259] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
This review highlights the role of three key immune pathways in the pathophysiology of major retinal degenerative diseases including diabetic retinopathy, age‐related macular degeneration, and rare retinal dystrophies. We first discuss the mechanisms how loss of retinal homeostasis evokes an unbalanced retinal immune reaction involving responses of local microglia and recruited macrophages, activity of the alternative complement system, and inflammasome assembly in the retinal pigment epithelium. Presenting these key mechanisms as complementary targets, we specifically emphasize the concept of immunomodulation as potential treatment strategy to prevent or delay vision loss. Promising molecules are ligands for phagocyte receptors, specific inhibitors of complement activation products, and inflammasome inhibitors. We comprehensively summarize the scientific evidence for this strategy from preclinical animal models, human ocular tissue analyses, and clinical trials evolving in the last few years.
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Affiliation(s)
- Isha Akhtar-Schäfer
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Luping Wang
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Tim U Krohne
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Heping Xu
- Centre for Experimental Medicine, The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany .,Center for Molecular Medicine, University of Cologne, Cologne, Germany
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41
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Bornhöfft KF, Galuska SP. Glycans as Modulators for the Formation and Functional Properties of Neutrophil Extracellular Traps: Used by the Forces of Good and Evil. Front Immunol 2019; 10:959. [PMID: 31134066 PMCID: PMC6514094 DOI: 10.3389/fimmu.2019.00959] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/15/2019] [Indexed: 12/13/2022] Open
Abstract
A very common mechanism to trap pathogens is the release of DNA. Like flies in a spider's web, pathogens are enclosed in a sticky chromatin meshwork. Interestingly, plants already use this mechanism to catch bacteria. In mammals, especially neutrophils release their DNA to prevent an invasion of bacteria. These neutrophil extracellular traps (NETs) are equipped with antimicrobial molecules, including, for instance, histones, antimicrobial peptides, lactoferrin, and neutrophil elastase. Thus, in a defined area, pathogens and toxic molecules are directly adjacent. However, several of these antimicrobial substances are also cytotoxic for endogenous cells. It is, therefore, not surprising that distinct control mechanisms exist to prevent an exaggerated NETosis. Nevertheless, despite these endogenous control instruments, an extraordinary NET release is characteristic for several pathologies. Consequently, NETs are a novel target for developing therapeutic strategies. In this review, we summarize the roles of glycans in the biology of NETs; on the one hand, we focus on the glycan-dependent strategies of endogenous cells to control NET formation or to inactivate its cytotoxic effects, and, on the other hand, the “sweet” tricks of pathogens to inhibit the release of NETs or to prevent NET-mediated killing mechanisms are examined. Understanding both, the forces of good and evil, allows the development of novel glycan-based approaches to combat the harmful side of NETs during distinct pathologies.
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Affiliation(s)
- Kim F Bornhöfft
- Institute of Reproductive Biology, Leibniz Institute for Farm Animal Biology, Dummerstorf, Germany
| | - Sebastian P Galuska
- Institute of Reproductive Biology, Leibniz Institute for Farm Animal Biology, Dummerstorf, Germany
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Abstract
In the past decade, the field of the cellular microbiology of group A Streptococcus (S. pyogenes) infection has made tremendous advances and touched upon several important aspects of pathogenesis, including receptor biology, invasive and evasive phenomena, inflammasome activation, strain-specific autophagic bacterial killing, and virulence factor-mediated programmed cell death. The noteworthy aspect of S. pyogenes-mediated cell signaling is the recognition of the role of M protein in a variety of signaling events, starting with the targeting of specific receptors on the cell surface and on through the induction and evasion of NETosis, inflammasome, and autophagy/xenophagy to pyroptosis and apoptosis. Variations in reports on S. pyogenes-mediated signaling events highlight the complex mechanism of pathogenesis and underscore the importance of the host cell and S. pyogenes strain specificity, as well as in vitro/in vivo experimental parameters. The severity of S. pyogenes infection is, therefore, dependent on the virulence gene expression repertoire in the host environment and on host-specific dynamic signaling events in response to infection. Commonly known as an extracellular pathogen, S. pyogenes finds host macrophages as safe havens wherein it survives and even multiplies. The fact that endothelial cells are inherently deficient in autophagic machinery compared to epithelial cells and macrophages underscores the invasive nature of S. pyogenes and its ability to cause severe systemic diseases. S. pyogenes is still one of the top 10 causes of infectious mortality. Understanding the orchestration of dynamic host signaling networks will provide a better understanding of the increasingly complex mechanism of S. pyogenes diseases and novel ways of therapeutically intervening to thwart severe and often fatal infections.
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Landig CS, Hazel A, Kellman BP, Fong JJ, Schwarz F, Agarwal S, Varki N, Massari P, Lewis NE, Ram S, Varki A. Evolution of the exclusively human pathogen Neisseria gonorrhoeae: Human-specific engagement of immunoregulatory Siglecs. Evol Appl 2019; 12:337-349. [PMID: 30697344 PMCID: PMC6346652 DOI: 10.1111/eva.12744] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Accepted: 11/14/2018] [Indexed: 12/18/2022] Open
Abstract
Neisseria gonorrhoeae causes the sexually transmitted disease gonorrhea exclusively in humans and uses multiple strategies to infect, including acquisition of host sialic acids that cap and mask lipooligosaccharide termini, while restricting complement activation. We hypothesized that gonococci selectively target human anti-inflammatory sialic acid-recognizing Siglec receptors on innate immune cells to blunt host responses and that pro-inflammatory Siglecs and SIGLEC pseudogene polymorphisms represent host evolutionary adaptations to counteract this interaction. N. gonorrhoeae can indeed engage multiple human but not chimpanzee CD33rSiglecs expressed on innate immune cells and in the genitourinary tract--including Siglec-11 (inhibitory) and Siglec-16 (activating), which we detected for the first time on human cervical epithelium. Surprisingly, in addition to LOS sialic acid, we found that gonococcal porin (PorB) mediated binding to multiple Siglecs. PorB also bound preferentially to human Siglecs and not chimpanzee orthologs, modulating host immune reactions in a human-specific manner. Lastly, we studied the distribution of null SIGLEC polymorphisms in a Namibian cohort with a high prevalence of gonorrhea and found that uninfected women preferentially harbor functional SIGLEC16 alleles encoding an activating immune receptor. These results contribute to the understanding of the human specificity of N. gonorrhoeae and how it evolved to evade the human immune defense.
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Affiliation(s)
- Corinna S. Landig
- Glycobiology Research and Training CenterUniversity of California, San DiegoLa JollaCalifornia
- Department of Cellular and Molecular MedicineUniversity of California, San DiegoLa JollaCalifornia
- Department of MedicineUniversity of California, San DiegoLa JollaCalifornia
| | - Ashley Hazel
- Department of Earth System ScienceStanford UniversityStanfordCalifornia
| | - Benjamin P. Kellman
- Department of PediatricsUniversity of California, San DiegoLa JollaCalifornia
- Bioinformatics and Systems Biology Graduate ProgramUniversity of California, San DiegoLa JollaCalifornia
| | - Jerry J. Fong
- Glycobiology Research and Training CenterUniversity of California, San DiegoLa JollaCalifornia
- Department of Cellular and Molecular MedicineUniversity of California, San DiegoLa JollaCalifornia
- Department of MedicineUniversity of California, San DiegoLa JollaCalifornia
| | - Flavio Schwarz
- Glycobiology Research and Training CenterUniversity of California, San DiegoLa JollaCalifornia
- Department of Cellular and Molecular MedicineUniversity of California, San DiegoLa JollaCalifornia
- Department of MedicineUniversity of California, San DiegoLa JollaCalifornia
| | - Sarika Agarwal
- Department of MedicineUniversity of Massachusetts Medical SchoolWorcesterMassachusetts
| | - Nissi Varki
- Glycobiology Research and Training CenterUniversity of California, San DiegoLa JollaCalifornia
- Department of PathologyUniversity of California, San DiegoLa JollaCalifornia
| | - Paola Massari
- Department of ImmunologyTufts University School of MedicineBostonMassachusetts
| | - Nathan E. Lewis
- Department of PediatricsUniversity of California, San DiegoLa JollaCalifornia
- Bioinformatics and Systems Biology Graduate ProgramUniversity of California, San DiegoLa JollaCalifornia
- Novo Nordisk Foundation Center for BiosustainabilityUniversity of California, San DiegoLa JollaCalifornia
| | - Sanjay Ram
- Department of MedicineUniversity of Massachusetts Medical SchoolWorcesterMassachusetts
| | - Ajit Varki
- Glycobiology Research and Training CenterUniversity of California, San DiegoLa JollaCalifornia
- Department of Cellular and Molecular MedicineUniversity of California, San DiegoLa JollaCalifornia
- Department of MedicineUniversity of California, San DiegoLa JollaCalifornia
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44
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Barrow AD, Colonna M. Exploiting NK Cell Surveillance Pathways for Cancer Therapy. Cancers (Basel) 2019; 11:cancers11010055. [PMID: 30626155 PMCID: PMC6356551 DOI: 10.3390/cancers11010055] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 12/28/2018] [Accepted: 01/03/2019] [Indexed: 12/27/2022] Open
Abstract
Natural killer (NK) cells can evoke potent anti-tumour activity. This function is largely mediated through a battery of specialised cell-surface receptors which probe the tissue microenvironment for changes in surface and secretory phenotypes that may alert to the presence of infection or malignancy. These receptors have the potential to arouse the robust cytotoxic and cytokine-secreting functions of NK cells and so must be tightly regulated to prevent autoimmunity. However, such functions also hold great promise for clinical intervention. In this review, we highlight some of the latest breakthroughs in fundamental NK cell receptor biology that have illuminated our understanding of the molecular strategies NK cells employ to perceive malignant cells from normal healthy cells. Moreover, we highlight how these sophisticated tumour recognition strategies are being harnessed for cancer immunotherapies in the clinic.
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Affiliation(s)
- Alexander David Barrow
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC 3000, Australia.
| | - Marco Colonna
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Adams OJ, Stanczak MA, von Gunten S, Läubli H. Targeting sialic acid-Siglec interactions to reverse immune suppression in cancer. Glycobiology 2018; 28:640-647. [PMID: 29309569 DOI: 10.1093/glycob/cwx108] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 12/19/2017] [Indexed: 12/17/2022] Open
Abstract
Changes in sialic acids in cancer have been observed for many years. In particular, the increase of sialoglycan density or hypersialylation in tumors has been described. Recent studies have identified mechanisms for immune evasion based on sialoglycan interactions with immunoregulatory Siglec receptors that are exploited by tumor cells and microorganisms alike. Siglecs are mostly inhibitory receptors similar to known immune checkpoints including PD-1 or CTLA-4 that are successfully targeted with blocking antibodies for cancer immunotherapy. Here, we summarize the known changes of sialic acids in cancer and the role Siglec receptors play in cancer immunity. We also focus on potential ways to target these Siglec receptors or sialoglycans in order to improve anti-cancer immunity.
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Affiliation(s)
- Olivia Joan Adams
- Institute of Pharmacology, University of Bern, Inselspital INO-F, Bern, Switzerland
| | | | - Stephan von Gunten
- Institute of Pharmacology, University of Bern, Inselspital INO-F, Bern, Switzerland
| | - Heinz Läubli
- Laboratory of Cancer Immunology, Department of Biomedicine.,Medical Oncology, Department of Internal Medicine, University Hospital Basel, Petersgraben 4, Basel, Switzerland
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46
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Lübbers J, Rodríguez E, van Kooyk Y. Modulation of Immune Tolerance via Siglec-Sialic Acid Interactions. Front Immunol 2018; 9:2807. [PMID: 30581432 PMCID: PMC6293876 DOI: 10.3389/fimmu.2018.02807] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/14/2018] [Indexed: 12/11/2022] Open
Abstract
One of the key features of the immune system is its extraordinary capacity to discriminate between self and non-self and to respond accordingly. Several molecular interactions allow the induction of acquired immune responses when a foreign antigen is recognized, while others regulate the resolution of inflammation, or the induction of tolerance to self-antigens. Post-translational signatures, such as glycans that are part of proteins (glycoproteins) and lipids (glycolipids) of host cells or pathogens, are increasingly appreciated as key molecules in regulating immunity vs. tolerance. Glycans are sensed by glycan binding receptors expressed on immune cells, such as C-type lectin receptors (CLRs) and Sialic acid binding immunoglobulin type lectins (Siglecs), that respond to specific glycan signatures by triggering tolerogenic or immunogenic signaling pathways. Glycan signatures present on healthy tissue, inflamed and malignant tissue or pathogens provide signals for “self” or “non-self” recognition. In this review we will focus on sialic acids that serve as “self” molecular pattern ligands for Siglecs. We will emphasize on the function of Siglec-expressing mononuclear phagocytes as sensors for sialic acids in tissue homeostasis and describe how the sialic acid-Siglec axis is exploited by tumors and pathogens for the induction of immune tolerance. Furthermore, we highlight how the sialic acid-Siglec axis can be utilized for clinical applications to induce or inhibit immune tolerance.
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Affiliation(s)
- Joyce Lübbers
- Molecular Cell Biology and Immunology, Amsterdam UMC, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, Amsterdam Infection and Immunity Institute, Amsterdam, Netherlands
| | - Ernesto Rodríguez
- Molecular Cell Biology and Immunology, Amsterdam UMC, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, Amsterdam Infection and Immunity Institute, Amsterdam, Netherlands
| | - Yvette van Kooyk
- Molecular Cell Biology and Immunology, Amsterdam UMC, Vrije Universiteit Amsterdam, Cancer Center Amsterdam, Amsterdam Infection and Immunity Institute, Amsterdam, Netherlands
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47
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Angata T. Possible Influences of Endogenous and Exogenous Ligands on the Evolution of Human Siglecs. Front Immunol 2018; 9:2885. [PMID: 30564250 PMCID: PMC6288428 DOI: 10.3389/fimmu.2018.02885] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/23/2018] [Indexed: 12/25/2022] Open
Abstract
Sialic acids, a group of acidic sugars abundantly expressed in the tissues of deuterostome animals but rarely found in microbes, serve as a "signature of self" for these animals. Cognate sensors for sialic acids include Siglecs, a family of transmembrane lectins of vertebrate immune systems that recognize glycans containing sialic acids. A type of sialic acid called N-glycolylneuraminic acid (Neu5Gc) is abundant in many mammalian lineages including great apes, the closest extant relatives of modern human, but was lost in the lineage leading to modern human via the pseudogenization of the CMAH gene encoding the enzyme that converts N-acetylneuraminic acid (Neu5Ac) to Neu5Gc. Loss of Neu5Gc appears to have influenced the evolution of human Siglecs, such as the adjustment of sialic acid binding preferences and the inactivation of at least one Siglec. In addition, various mechanistic studies using model systems and genetic association studies have revealed that some human Siglecs interact with pathogens and influence the outcome of infections, and these pathogens in turn likely influence the evolution of these Siglecs. By understanding the evolutionary forces affecting Siglecs, we shall achieve a better appreciation of Siglec functions, and by understanding Siglec functions, we can obtain deeper insight into the evolutionary processes driving Siglec evolution.
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Affiliation(s)
- Takashi Angata
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
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48
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Fong JJ, Tsai CM, Saha S, Nizet V, Varki A, Bui JD. Siglec-7 engagement by GBS β-protein suppresses pyroptotic cell death of natural killer cells. Proc Natl Acad Sci U S A 2018; 115:10410-10415. [PMID: 30254166 PMCID: PMC6187154 DOI: 10.1073/pnas.1804108115] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Natural killer (NK) cells are innate immune lymphocytes that recognize and destroy abnormal host cells, such as tumor cells or those infected by viral pathogens. To safely accomplish these functions, NK cells display activating receptors that detect stress molecules or viral ligands displayed at the cell surface, balanced by inhibitory receptors that bind to self-molecules. To date, such activating and inhibitory receptors on NK cells are not known to recognize bacterial determinants. Moreover, NK cell responses to direct interactions with extracellular bacteria are poorly explored. In this study, we observed the human neonatal pathogen group B Streptococcus (GBS) can directly engage human NK cells. The interaction was mediated through the B6N segment of streptococcal β-protein, binding to the inhibitory receptor Siglec-7 via its amino-terminal V-set domain. Unlike classical Siglec binding, the interaction is also independent of its sialic acid recognition property. In contrast to WT GBS, mutants lacking β-protein induced efficient pyroptosis of NK cells through the NLRP3 inflammasome, with production and secretion of the proinflammatory cytokine IL-1β and dissemination of the cytotoxic molecule granzyme B. We postulate that GBS evolved β-protein engagement of inhibitory human Siglec-7 to suppress the pyroptotic response of NK cells and thereby block recruitment of a broader innate immune response, i.e., by "silencing the sentinel."
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Affiliation(s)
- Jerry J Fong
- Glycobiology Research and Training Center, School of Medicine, University of California, San Diego, La Jolla, CA 92093
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Chih-Ming Tsai
- Glycobiology Research and Training Center, School of Medicine, University of California, San Diego, La Jolla, CA 92093
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Sudeshna Saha
- Glycobiology Research and Training Center, School of Medicine, University of California, San Diego, La Jolla, CA 92093
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Victor Nizet
- Glycobiology Research and Training Center, School of Medicine, University of California, San Diego, La Jolla, CA 92093
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, CA 92093
- Skaggs School of Pharmacy and Pharmaceutical Sciences, School of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Ajit Varki
- Glycobiology Research and Training Center, School of Medicine, University of California, San Diego, La Jolla, CA 92093;
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Jack D Bui
- Department of Pathology, School of Medicine, University of California, San Diego, La Jolla, CA 92093
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49
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Stanczak MA, Siddiqui SS, Trefny MP, Thommen DS, Boligan KF, von Gunten S, Tzankov A, Tietze L, Lardinois D, Heinzelmann-Schwarz V, von Bergwelt-Baildon M, Zhang W, Lenz HJ, Han Y, Amos CI, Syedbasha M, Egli A, Stenner F, Speiser DE, Varki A, Zippelius A, Läubli H. Self-associated molecular patterns mediate cancer immune evasion by engaging Siglecs on T cells. J Clin Invest 2018; 128:4912-4923. [PMID: 30130255 DOI: 10.1172/jci120612] [Citation(s) in RCA: 171] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 08/16/2018] [Indexed: 12/17/2022] Open
Abstract
First-generation immune checkpoint inhibitors, including anti-CTLA-4 and anti-programmed death 1 (anti-PD-1) antibodies, have led to major clinical progress, yet resistance frequently leads to treatment failure. Thus, new targets acting on T cells are needed. CD33-related sialic acid-binding immunoglobulin-like lectins (Siglecs) are pattern-recognition immune receptors binding to a range of sialoglycan ligands, which appear to function as self-associated molecular patterns (SAMPs) that suppress autoimmune responses. Siglecs are expressed at very low levels on normal T cells, and these receptors were not until recently considered as interesting targets on T cells for cancer immunotherapy. Here, we show an upregulation of Siglecs, including Siglec-9, on tumor-infiltrating T cells from non-small cell lung cancer (NSCLC), colorectal, and ovarian cancer patients. Siglec-9-expressing T cells coexpressed several inhibitory receptors, including PD-1. Targeting of the sialoglycan-SAMP/Siglec pathway in vitro and in vivo resulted in increased anticancer immunity. T cell expression of Siglec-9 in NSCLC patients correlated with reduced survival, and Siglec-9 polymorphisms showed association with the risk of developing lung and colorectal cancer. Our data identify the sialoglycan-SAMP/Siglec pathway as a potential target for improving T cell activation for immunotherapy.
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Affiliation(s)
- Michal A Stanczak
- Cancer Immunology Laboratory, Department of Biomedicine, and.,Division of Oncology, Department of Internal Medicine, University Hospital, Basel, Switzerland
| | - Shoib S Siddiqui
- Departments of Medicine and Cellular and Molecular Medicine, Glycobiology Research and Training Center, UCSD, La Jolla, California, USA
| | - Marcel P Trefny
- Cancer Immunology Laboratory, Department of Biomedicine, and.,Division of Oncology, Department of Internal Medicine, University Hospital, Basel, Switzerland
| | - Daniela S Thommen
- Cancer Immunology Laboratory, Department of Biomedicine, and.,Division of Oncology, Department of Internal Medicine, University Hospital, Basel, Switzerland
| | | | | | - Alexandar Tzankov
- Institute of Pathology, University Hospital Basel, Basel, Switzerland
| | | | | | | | | | - Wu Zhang
- USC, Los Angeles, California, USA
| | | | | | | | | | - Adrian Egli
- Applied Microbiology Research, University Hospital, Basel, Switzerland
| | - Frank Stenner
- Cancer Immunology Laboratory, Department of Biomedicine, and.,Division of Oncology, Department of Internal Medicine, University Hospital, Basel, Switzerland
| | - Daniel E Speiser
- Ludwig Cancer Research Center, University of Lausanne, Lausanne, Switzerland
| | - Ajit Varki
- Departments of Medicine and Cellular and Molecular Medicine, Glycobiology Research and Training Center, UCSD, La Jolla, California, USA
| | - Alfred Zippelius
- Cancer Immunology Laboratory, Department of Biomedicine, and.,Division of Oncology, Department of Internal Medicine, University Hospital, Basel, Switzerland
| | - Heinz Läubli
- Cancer Immunology Laboratory, Department of Biomedicine, and.,Division of Oncology, Department of Internal Medicine, University Hospital, Basel, Switzerland
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50
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Cross BW, Ruhl S. Glycan recognition at the saliva - oral microbiome interface. Cell Immunol 2018; 333:19-33. [PMID: 30274839 DOI: 10.1016/j.cellimm.2018.08.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 08/16/2018] [Accepted: 08/17/2018] [Indexed: 01/25/2023]
Abstract
The mouth is a first critical interface where most potentially harmful substances or pathogens contact the host environment. Adaptive and innate immune defense mechanisms are established there to inactivate or eliminate pathogenic microbes that traverse the oral environment on the way to their target organs and tissues. Protein and glycoprotein components of saliva play a particularly important role in modulating the oral microbiota and helping with the clearance of pathogens. It has long been acknowledged that glycobiological and glycoimmunological aspects play a pivotal role in oral host-microbe, microbe-host, and microbe-microbe interactions in the mouth. In this review, we aim to delineate how glycan-mediated host defense mechanisms in the oral cavity support human health. We will describe the role of glycans attached to large molecular size salivary glycoproteins which act as a first line of primordial host defense in the human mouth. We will further discuss how glycan recognition contributes to both colonization and clearance of oral microbes.
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Affiliation(s)
- Benjamin W Cross
- Department of Oral Biology, University at Buffalo, Buffalo, NY, United States
| | - Stefan Ruhl
- Department of Oral Biology, University at Buffalo, Buffalo, NY, United States.
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