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Hutton E, Scott E, Robson CN, Signoret N, Fascione MA. A systematic review reveals conflicting evidence for the prevalence of antibodies against the sialic acid 'xenoautoantigen' Neu5Gc in humans and the need for a standardised approach to quantification. Front Mol Biosci 2024; 11:1390711. [PMID: 38737334 PMCID: PMC11082328 DOI: 10.3389/fmolb.2024.1390711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 03/26/2024] [Indexed: 05/14/2024] Open
Abstract
Despite an array of hypothesised implications for health, disease, and therapeutic development, antibodies against the non-human sialic acid N-glycolylneuraminic acid (Neu5Gc) remain a subject of much debate. This systematic review of 114 publications aimed to generate a comprehensive overview of published studies in this field, addressing both the reported prevalence of anti-Neu5Gc antibodies in the human population and whether experimental variation accounts for the conflicting reports about the extent of this response. Absolute titres of anti-Neu5Gc antibodies, the reported prevalence of these antibodies, and the individual variation observed within experiments were analysed and grouped according to biological context ('inflammation', 'xenotransplantation', 'biotherapeutic use', 'cancer', and 'healthy populations'), detection method, target epitope selection, and choice of blocking agent. These analyses revealed that the experimental method had a notable impact on both the reported prevalence and absolute titres of anti-Neu5Gc antibodies in the general population, thereby limiting the ability to ascribe reported trends to genuine biological differences or the consequence of experimental design. Overall, this review highlights important knowledge gaps in the study of antibodies against this important xenoautoantigen and the need to establish a standardised method for their quantification if the extent of the importance of Neu5Gc in human health is to be fully understood.
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Affiliation(s)
- Esme Hutton
- Department of Chemistry, University of York, York, United Kingdom
- Hull York Medical School, University of York, York, United Kingdom
| | - Emma Scott
- Newcastle University, Centre for Cancer, Newcastle University Biosciences Institute, Newcastle, United Kingdom
| | - Craig N. Robson
- Newcastle University, Centre for Cancer, Newcastle University Translational and Clinical Research Institute, Newcastle, United Kingdom
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Wen R, Zhao H, Zhang D, Chiu CL, Brooks JD. Sialylated glycoproteins as biomarkers and drivers of progression in prostate cancer. Carbohydr Res 2022; 519:108598. [DOI: 10.1016/j.carres.2022.108598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 04/20/2022] [Accepted: 05/20/2022] [Indexed: 01/27/2023]
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Lin X, Yao H, Guo J, Huang Y, Wang W, Yin B, Li X, Wang T, Li C, Xu X, Zhou G, Voglmeir J, Liu L. Protein Glycosylation and Gut Microbiota Utilization Can Limit the in vitro and in vivo Metabolic Cellular Incorporation of Neu5Gc. Mol Nutr Food Res 2021; 66:e2100615. [PMID: 34921741 DOI: 10.1002/mnfr.202100615] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 12/01/2021] [Indexed: 11/06/2022]
Abstract
SCOPE Red meat intake was reported to be correlated with chronic diseases. A potential causal factor is N-glycolylneuraminic acid (Neu5Gc) which metabolically incorporates into diverse glycoconjugates in humans. This study aims to investigate the impact of exposure to Neu5Gc-rich red meat on healthy cytidine-5'-monophospho-N-acetylneuraminic acid hydroxylase (Cmah) knock-out mice and the underlying mechanisms. METHODS AND RESULTS CMAH-/- mice were fed Neu5Gc-rich diet for short-term (4 months) and long-term (10 months). Health status and levels of inflammatory cytokines were assessed. Caco-2 cells were used to investigate the intestinal absorption of Neu5Gc-containing glycoprotein, and in vitro fermentation was used to investigate the Neu5Gc utilization by gut microbiota. Neu5Gc-rich diets showed neither measurable abnormality in physio-biochemical and inflammatory indexes nor observable alterations of liver tissue in mice. Glycosylation of lactoferrin limited its intestinal epithelial absorption, and the absorption of Neu5Gc attached onto glycoprotein was thus limited. Neu5Gc was also simultaneously utilized by microorganisms under simulated gut conditions. CONCLUSION The results indicated that the long-term intake of Neu5Gc-rich red meat had no adverse effect on the health of CMAH-/- mice, which may be related to the limited absorption of Neu5Gc regulated by protein glycosylation, and the metabolism of Neu5Gc by gut microorganisms. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Xisha Lin
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Hongliang Yao
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China.,Food Science Department, Jinling Institute of Technology, Nanjing, China
| | - Jingyu Guo
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Yingying Huang
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Wenjiao Wang
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Binru Yin
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Xiang'an Li
- Haidu College, Qingdao Agricultural University, Qingdao, China
| | - Ting Wang
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Chunbao Li
- Jiangsu Collaborative Innovation Center of Meat Production, Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Xinglian Xu
- Jiangsu Collaborative Innovation Center of Meat Production, Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Guanghong Zhou
- Jiangsu Collaborative Innovation Center of Meat Production, Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Josef Voglmeir
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China.,Jiangsu Collaborative Innovation Center of Meat Production, Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Li Liu
- Glycomics and Glycan Bioengineering Research Center (GGBRC), College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China.,Jiangsu Collaborative Innovation Center of Meat Production, Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
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Mastrangeli R, Audino MC, Palinsky W, Broly H, Bierau H. Current views on N-glycolylneuraminic acid in therapeutic recombinant proteins. Trends Pharmacol Sci 2021; 42:943-956. [PMID: 34544608 DOI: 10.1016/j.tips.2021.08.004] [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: 04/21/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 10/20/2022]
Abstract
The incorporation of the non-human N-glycolylneuraminic acid (Neu5Gc) in therapeutic recombinant proteins raises clinical concerns due to its immunogenic potential and the high prevalence of pre-existing anti-Neu5Gc antibodies in humans. The scientific literature is ambiguous regarding the actual impact of Neu5Gc-containing biotherapeutics as no severe adverse clinical manifestations were unequivocally attributed to Neu5Gc for currently marketed biotherapeutics. This review discusses structural and functional considerations of Neu5Gc-containing glycans regarding the potential impact on drug clearance, their recognition by pre-existing antibodies, and recent hypotheses regarding the tolerance to low Neu5Gc levels. Furthermore, it provides recommendations regarding the standardization of analysis and reporting, analytical aspects relevant for assessing risks associated with Neu5Gc-containing biotherapeutics, and approaches to minimize Neu5Gc incorporation in recombinant protein manufacturing.
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Affiliation(s)
- Renato Mastrangeli
- Technology & Innovation, CMC Science & Intelligence, Merck Serono SpA (an affiliate of Merck KgaA, Darmstadt, Germany), Guidonia Montecelio (Rome), Italy
| | - Maria Concetta Audino
- Technology & Innovation, CMC Science & Intelligence, Merck Serono SpA (an affiliate of Merck KgaA, Darmstadt, Germany), Guidonia Montecelio (Rome), Italy
| | - Wolf Palinsky
- Biotech Development Programme, Merck Biopharma (an affiliate of Merck KgaA, Darmstadt, Germany), Aubonne, Switzerland
| | - Hervé Broly
- Biotech Process Sciences, Merck Serono S.A. (an affiliate of Merck KgaA, Darmstadt, Germany), Corsier-sur-Vevey, Switzerland
| | - Horst Bierau
- Technology & Innovation, CMC Science & Intelligence, Merck Serono SpA (an affiliate of Merck KgaA, Darmstadt, Germany), Guidonia Montecelio (Rome), Italy.
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Bashir S, Fezeu LK, Leviatan Ben-Arye S, Yehuda S, Reuven EM, Szabo de Edelenyi F, Fellah-Hebia I, Le Tourneau T, Imbert-Marcille BM, Drouet EB, Touvier M, Roussel JC, Yu H, Chen X, Hercberg S, Cozzi E, Soulillou JP, Galan P, Padler-Karavani V. Association between Neu5Gc carbohydrate and serum antibodies against it provides the molecular link to cancer: French NutriNet-Santé study. BMC Med 2020; 18:262. [PMID: 32962714 PMCID: PMC7510162 DOI: 10.1186/s12916-020-01721-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 07/27/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND High consumption of red and processed meat is commonly associated with increased cancer risk, particularly colorectal cancer. Antibodies against the red meat-derived carbohydrate N-glycolylneuraminic acid (Neu5Gc) exacerbate cancer in "human-like" mice. Human anti-Neu5Gc IgG and red meat are both independently proposed to increase cancer risk, yet how diet affects these antibodies is largely unknown. METHODS We used world global data to demonstrate that colorectal cancer incidence and mortality are associated with increased national meat consumption. In a well-defined large cohort, we used glycomics to measure daily Neu5Gc intake from red meat and dairy, and investigated serum as well as affinity-purified anti-Neu5Gc antibodies. Based on 24-h dietary records, daily Neu5Gc intake was calculated for 19,621 subjects aged ≥ 18 years of the NutriNet-Santé study. Serum and affinity-purified anti-Neu5Gc antibodies were evaluated by ELISA and glycan microarrays in representative 120 individuals, each with at least eighteen 24-h dietary records (aged 45-60, Q1-Q4; aged > 60, Q1 and Q4; 10 men/women per quartile). RESULTS We found that high-Neu5Gc diet, gender, and age affect the specificity, levels, and repertoires of anti-Neu5Gc IgG immune responses, but not their affinity. Men consumed more Neu5Gc than women, mostly from red meat (p = 0.0015), and exhibited higher overall serum anti-Neu5Gc IgG levels by ELISA (3.94 ng/μl versus 2.22 ng/μl, respectively; p = 0.039). Detailed glycan microarray analysis against 56 different glycans revealed high Neu5Gc-specificity with increased anti-Neu5Gc IgG and altered repertoires, associated with higher consumption of Neu5Gc from red meat and cow dairy. Affinity purification of serum anti-Neu5Gc antibodies revealed increased levels and biased array repertoire patterns, without an increase in antibody affinity, in individuals consuming higher Neu5Gc levels. Furthermore, in a high-meat diet, antibody diversity patterns on glycan microarrays shifted towards Neu5Gcα3-linked glycans, increasing the α3/α6-glycans ratio score. CONCLUSIONS We found a clear link between the levels and repertoire of serum anti-Neu5Gc IgG and Neu5Gc intake from red meat and dairy. These precise rational methodologies allowed to develop a Gcemic index to simplify the assessment of Neu5Gc in foods that could potentially be adapted for dietary recommendations to reduce cancer risk.
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Affiliation(s)
- Salam Bashir
- Department of Cell Research and Immunology, The Shmunis School of Biomedicine and Cancer Research, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Leopold K Fezeu
- Sorbonne Paris Cité Epidemiology and Statistics Research Center (CRESS), Inserm U1153, Inra U1125, Cnam, Paris 13 University, Nutritional Epidemiology Research Team (EREN), Bobigny, France
| | - Shani Leviatan Ben-Arye
- Department of Cell Research and Immunology, The Shmunis School of Biomedicine and Cancer Research, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Sharon Yehuda
- Department of Cell Research and Immunology, The Shmunis School of Biomedicine and Cancer Research, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Eliran Moshe Reuven
- Department of Cell Research and Immunology, The Shmunis School of Biomedicine and Cancer Research, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Fabien Szabo de Edelenyi
- Sorbonne Paris Cité Epidemiology and Statistics Research Center (CRESS), Inserm U1153, Inra U1125, Cnam, Paris 13 University, Nutritional Epidemiology Research Team (EREN), Bobigny, France
| | - Imen Fellah-Hebia
- Department of Thoracic and Cardiovascular Surgery, Institut du Thorax, University Hospital, Nantes, France
| | - Thierry Le Tourneau
- Department of Cardiology, Institut du Thorax, University Hospital, Nantes, France
| | | | - Emmanuel B Drouet
- Institute of Structural Biology, University Grenoble Alpes, UMR CNRS CEA UGA 5545 CEA, CNRS 38044, F38042, Grenoble, France
| | - Mathilde Touvier
- Sorbonne Paris Cité Epidemiology and Statistics Research Center (CRESS), Inserm U1153, Inra U1125, Cnam, Paris 13 University, Nutritional Epidemiology Research Team (EREN), Bobigny, France
| | - Jean-Christian Roussel
- Department of Thoracic and Cardiovascular Surgery, Institut du Thorax, University Hospital, Nantes, France
| | - Hai Yu
- Department of Chemistry, University of California-Davis, Davis, CA, 95616, USA
| | - Xi Chen
- Department of Chemistry, University of California-Davis, Davis, CA, 95616, USA
| | - Serge Hercberg
- Sorbonne Paris Cité Epidemiology and Statistics Research Center (CRESS), Inserm U1153, Inra U1125, Cnam, Paris 13 University, Nutritional Epidemiology Research Team (EREN), Bobigny, France
| | - Emanuele Cozzi
- Transplant Immunology Unit, Department of Cardiac, Thoracic and Vascular Sciences, Padua University Hospital, Padua, Italy
| | - Jean-Paul Soulillou
- Centre de Recherche en Transplantation et Immunologie UMR 1064, INSERM, Université de Nantes, Nantes, France
| | - Pilar Galan
- Sorbonne Paris Cité Epidemiology and Statistics Research Center (CRESS), Inserm U1153, Inra U1125, Cnam, Paris 13 University, Nutritional Epidemiology Research Team (EREN), Bobigny, France
| | - Vered Padler-Karavani
- Department of Cell Research and Immunology, The Shmunis School of Biomedicine and Cancer Research, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel.
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Soulillou JP, Cozzi E, Bach JM. Challenging the Role of Diet-Induced Anti-Neu5Gc Antibodies in Human Pathologies. Front Immunol 2020; 11:834. [PMID: 32655538 PMCID: PMC7325919 DOI: 10.3389/fimmu.2020.00834] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 04/14/2020] [Indexed: 12/19/2022] Open
Affiliation(s)
- Jean-Paul Soulillou
- Centre de Recherche en Transplantation et Immunologie (CRTI), INSERM, Université de Nantes, and Institut de Transplantation Urologie Néphrologie (ITUN), CHU Nantes, Nantes, France
| | - Emanuele Cozzi
- Department of Cardiac, Thoracic and Vascular Sciences, Transplant Immunology Unit, Padua University Hospital, Padua, Italy
| | - Jean-Marie Bach
- IECM, Immuno-Endocrinology, USC1383, Oniris, INRAE, Nantes, France
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7
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Tector AJ, Mosser M, Tector M, Bach JM. The Possible Role of Anti-Neu5Gc as an Obstacle in Xenotransplantation. Front Immunol 2020; 11:622. [PMID: 32351506 PMCID: PMC7174778 DOI: 10.3389/fimmu.2020.00622] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 03/18/2020] [Indexed: 12/20/2022] Open
Abstract
Seventy to ninety percentage of preformed xenoreactive antibodies in human serum bind to the galactose-α(1,3)-galactose Gal epitope, and the creation of Gal knockout (KO) pigs has eliminated hyperacute rejection as a barrier to xenotransplantation. Now other glycan antigens are barriers to move ahead with xenotransplantation, and the N-glycolyl neuraminic acid, Neu5Gc (or Hanganutziu-Deicher antigen), is also a major pig xenoantigen. Humans have anti-Neu5Gc antibodies. Several data indicate a strong immunogenicity of Neu5Gc in humans that may contribute to an important part in antibody-dependent injury to pig xenografts. Pig islets express Neu5Gc, which reacted with diet-derived human antibodies and mice deleted for Neu5Gc reject pancreatic islets from wild-type counterpart. However, Neu5Gc positive heart were not rejected in Neu5Gc KO mice indicating that the role of Neu5Gc-specific antibodies has to be nuanced and depend of the graft situation parameters (organ/tissue, recipient, implication of other glycan antigens). Recently generated Gal/Neu5Gc KO pigs eliminate the expression of Gal and Neu5Gc, and improve the crossmatch of humans with the pig. This review summarizes the current and recent experimental and (pre)clinical data on the Neu5Gc immunogenicity and emphasize of the potential impact of anti-Neu5Gc antibodies in limiting xenotransplantation in humans.
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Affiliation(s)
- Alfred Joseph Tector
- Department of Surgery, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
| | - Mathilde Mosser
- Immuno-Endocrinology Unit (IECM), USC1383, Oniris, INRA, Nantes, France
| | - Matthew Tector
- Department of Surgery, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
| | - Jean-Marie Bach
- Immuno-Endocrinology Unit (IECM), USC1383, Oniris, INRA, Nantes, France
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Yehuda S, Padler-Karavani V. Glycosylated Biotherapeutics: Immunological Effects of N-Glycolylneuraminic Acid. Front Immunol 2020; 11:21. [PMID: 32038661 PMCID: PMC6989436 DOI: 10.3389/fimmu.2020.00021] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 01/07/2020] [Indexed: 12/14/2022] Open
Abstract
The emerging field of biotherapeutics provides successful treatments for various diseases, yet immunogenicity and limited efficacy remain major concerns for many products. Glycosylation is a key factor determining the pharmacological properties of biotherapeutics, including their stability, solubility, bioavailability, pharmacokinetics, and immunogenicity. Hence, an increased attention is directed at optimizing the glycosylation properties of biotherapeutics. Currently, most biotherapeutics are produced in non-human mammalian cells in light of their ability to produce human-like glycosylation. However, most mammals produce the sialic acid N-glycolylneuraminic acid (Neu5Gc), while humans cannot due to a specific genetic defect. Humans consume Neu5Gc in their diet from mammalian derived foods (red meat and dairy) and produce polyclonal antibodies against diverse Neu5Gc-glycans. Moreover, Neu5Gc can metabolically incorporate into human cells and become presented on surface or secreted glycans, glycoproteins, and glycolipids. Several studies in mice suggested that the combination of Neu5Gc-containing epitopes and anti-Neu5Gc antibodies could contribute to exacerbation of chronic inflammation-mediated diseases (e.g., cancer, cardiovascular diseases, and autoimmunity). This could potentially become complicated with exposure to Neu5Gc-containing biotherapeutics, bio-devices or xenografts. Indeed, Neu5Gc can be found on various approved and marketed biotherapeutics. Here, we provide a perspective review on the possible consequences of Neu5Gc glycosylation of therapeutic protein drugs due to the limited published evidence of Neu5Gc glycosylation on marketed biotherapeutics and studies on their putative effects on immunogenicity, drug efficacy, and safety.
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Affiliation(s)
- Sharon Yehuda
- Department of Cell Research and Immunology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Vered Padler-Karavani
- Department of Cell Research and Immunology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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9
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Kooner AS, Yu H, Chen X. Synthesis of N-Glycolylneuraminic Acid (Neu5Gc) and Its Glycosides. Front Immunol 2019; 10:2004. [PMID: 31555264 PMCID: PMC6724515 DOI: 10.3389/fimmu.2019.02004] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 08/07/2019] [Indexed: 12/12/2022] Open
Abstract
Sialic acids constitute a family of negatively charged structurally diverse monosaccharides that are commonly presented on the termini of glycans in higher animals and some microorganisms. In addition to N-acetylneuraminic acid (Neu5Ac), N-glycolyl neuraminic acid (Neu5Gc) is among the most common sialic acid forms in nature. Nevertheless, unlike most animals, human cells loss the ability to synthesize Neu5Gc although Neu5Gc-containing glycoconjugates have been found on human cancer cells and in various human tissues due to dietary incorporation of Neu5Gc. Some pathogenic bacteria also produce Neu5Ac and the corresponding glycoconjugates but Neu5Gc-producing bacteria have yet to be found. In addition to Neu5Gc, more than 20 Neu5Gc derivatives have been found in non-human vertebrates. To explore the biological roles of Neu5Gc and its naturally occurring derivatives as well as the corresponding glycans and glycoconjugates, various chemical and enzymatic synthetic methods have been developed to obtain a vast array of glycosides containing Neu5Gc and/or its derivatives. Here we provide an overview on various synthetic methods that have been developed. Among these, the application of highly efficient one-pot multienzyme (OPME) sialylation systems in synthesizing compounds containing Neu5Gc and derivatives has been proven as a powerful strategy.
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Affiliation(s)
| | - Hai Yu
- Department of Chemistry, University of California, Davis, Davis, CA, United States
| | - Xi Chen
- Department of Chemistry, University of California, Davis, Davis, CA, United States
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Dhar C, Sasmal A, Varki A. From "Serum Sickness" to "Xenosialitis": Past, Present, and Future Significance of the Non-human Sialic Acid Neu5Gc. Front Immunol 2019; 10:807. [PMID: 31057542 PMCID: PMC6481270 DOI: 10.3389/fimmu.2019.00807] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 03/26/2019] [Indexed: 01/01/2023] Open
Abstract
The description of "serum sickness" more than a century ago in humans transfused with animal sera eventually led to identification of a class of human antibodies directed against glycans terminating in the common mammalian sialic acid N-Glycolylneuraminic acid (Neu5Gc), hereafter called "Neu5Gc-glycans." The detection of such glycans in malignant and fetal human tissues initially raised the possibility that it was an oncofetal antigen. However, "serum sickness" antibodies were also noted in various human disease states. These findings spurred further research on Neu5Gc, and the discovery that it is not synthesized in the human body due to a human-lineage specific genetic mutation in the enzyme CMAH. However, with more sensitive techniques Neu5Gc-glycans were detected in smaller quantities on certain human cell types, particularly epithelia and endothelia. The likely explanation is metabolic incorporation of Neu5Gc from dietary sources, especially red meat of mammalian origin. This incorporated Neu5Gc on glycans appears to be the first example of a "xeno-autoantigen," against which varying levels of "xeno-autoantibodies" are present in all humans. The resulting chronic inflammation or "xenosialitis" may have important implications in human health and disease, especially in conditions known to be aggravated by consumption of red meat. In this review, we will cover the early history of the discovery of "serum sickness" antibodies, the subsequent recognition that they were partly directed against Neu5Gc-glycans, the discovery of the genetic defect eliminating Neu5Gc production in humans, and the later recognition that this was not an oncofetal antigen but the first example of a "xeno-autoantigen." Further, we will present comments about implications for disease risks associated with red meat consumption such as cancer and atherosclerosis. We will also mention the potential utility of these anti-Neu5Gc-glycan antibodies in cancer immunotherapy and provide some suggestions and perspectives for the future. Other reviews in this special issue cover many other aspects of this unusual pathological process, for which there appears to be no other described precedent.
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Affiliation(s)
- Chirag Dhar
- Departments of Medicine and Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, United States.,Glycobiology Research and Training Center, University of California, San Diego, La Jolla, CA, United States
| | - Aniruddha Sasmal
- Departments of Medicine and Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, United States.,Glycobiology Research and Training Center, University of California, San Diego, La Jolla, CA, United States
| | - Ajit Varki
- Departments of Medicine and Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, United States.,Glycobiology Research and Training Center, University of California, San Diego, La Jolla, CA, United States
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