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Menghwar H, Tatum FM, Briggs RE, Casas E, Kaplan BS, Azadi P, Dassanayake RP. Enhanced phagocytosis and complement-mediated killing of Mannheimia haemolytica serotype 1 following in-frame CMP-sialic acid synthetase ( neuA) gene deletion. Microbiol Spectr 2023; 11:e0294423. [PMID: 37850751 PMCID: PMC10714724 DOI: 10.1128/spectrum.02944-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/06/2023] [Indexed: 10/19/2023] Open
Abstract
IMPORTANCE The Gram-negative coccobacillus Mannheimia haemolytica is a natural inhabitant of the upper respiratory tract in ruminants and the most common bacterial agent involved in bovine respiratory disease complex development. Key virulence factors harbored by M. haemolytica are leukotoxin, lipopolysaccharide, capsule, adhesins, and neuraminidase which are involved in evading innate and adaptive immune responses. In this study, we have shown that CMP-sialic acid synthetase (neuA) is necessary for the incorporation of sialic acid onto the membrane, and inactivation of neuA results in increased phagocytosis and complement-mediated killing of M. haemolytica, thus demonstrating that sialylation contributes to the virulence of M. haemolytica.
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Affiliation(s)
- Harish Menghwar
- Ruminant Diseases and Immunology Research Unit, United States Department of Agriculture, Agricultural Research Service, National Animal Disease Center, Ames, Iowa, USA
| | - Fred M. Tatum
- Ruminant Diseases and Immunology Research Unit, United States Department of Agriculture, Agricultural Research Service, National Animal Disease Center, Ames, Iowa, USA
| | - Robert E. Briggs
- Ruminant Diseases and Immunology Research Unit, United States Department of Agriculture, Agricultural Research Service, National Animal Disease Center, Ames, Iowa, USA
| | - Eduardo Casas
- Ruminant Diseases and Immunology Research Unit, United States Department of Agriculture, Agricultural Research Service, National Animal Disease Center, Ames, Iowa, USA
| | - Bryan S. Kaplan
- Ruminant Diseases and Immunology Research Unit, United States Department of Agriculture, Agricultural Research Service, National Animal Disease Center, Ames, Iowa, USA
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Rohana P. Dassanayake
- Ruminant Diseases and Immunology Research Unit, United States Department of Agriculture, Agricultural Research Service, National Animal Disease Center, Ames, Iowa, USA
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2
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Luo S, Liu Y, Hao T, Ma W, Luo Y, Wang S, Xu Z, Hu C, Wen L, Li T. Chemoenzymatic Total Synthesis of Haemophilus ducreyi Lipooligosaccharide Core Octasaccharides Containing Natural and Unnatural Sialic Acids. Org Lett 2023; 25:2312-2317. [PMID: 36972419 DOI: 10.1021/acs.orglett.3c00657] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
The first total synthesis of Haemophilus ducreyi lipooligosaccharide core octasaccharides containing natural and unnatural sialic acids has been achieved by an efficient chemoenzymatic approach. A highly convergent [3 + 3] coupling strategy was developed to chemically assemble a unique hexasaccharide bearing multiple rare higher-carbon sugars d-glycero-d-manno-heptose (d,d-Hep), l-glycero-d-manno-heptose (l,d-Hep), and 3-deoxy-α-d-manno-oct-2-ulosonic acid (Kdo). Key features include sequential one-pot glycosylations for oligosaccharide assembly and the construction of the challenging α-(1 → 5)-linked Hep-Kdo glycosidic bond by gold-catalyzed glycosylation with a glycosyl ortho-alkynylbenzoate donor. Furthermore, the sequential enzyme-catalyzed regio- and stereoselective introduction of a galactose residue using β-1,4-galactosyltransferase and different sialic acids using a one-pot multienzyme sialylation system was efficiently accomplished to provide the target octasaccharides.
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Affiliation(s)
- Shiwei Luo
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, China
| | - Yating Liu
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, China
| | - Tianhui Hao
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenjing Ma
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yawen Luo
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Shasha Wang
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, China
| | - Zhuojia Xu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Chaoyu Hu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Liuqing Wen
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, China
| | - Tiehai Li
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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3
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Yang H, Lu L, Chen X. An overview and future prospects of sialic acids. Biotechnol Adv 2020; 46:107678. [PMID: 33285252 DOI: 10.1016/j.biotechadv.2020.107678] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 11/11/2020] [Accepted: 11/30/2020] [Indexed: 12/21/2022]
Abstract
Sialic acids (Sias) are negatively charged functional monosaccharides present in a wide variety of natural sources (plants, animals and microorganisms). Sias play an important role in many life processes, which are widely applied in the medical and food industries as intestinal antibacterials, antivirals, anti-oxidative agents, food ingredients, and detoxification agents. Most Sias are composed of N-acetylneuraminic acid (Neu5Ac, >99%), and Sia is its most commonly used name. In this article, we review Sias in terms of their structures, applications, determination methods, metabolism, and production strategies. In particular, we summarise and compare different production strategies, including extraction from natural sources, chemical synthesis, polymer decomposition, enzymatic synthesis, whole-cell catalysis, and de novo biosynthesis via microorganism fermentation. We also discuss research on their physiological functions and applications, barriers to efficient production, and strategies for overcoming these challenges. We focus on efficient de novo biosynthesis strategies for Neu5Ac via microbial fermentation using novel synthetic biology tools and methods that may be applied in future. This work provides a comprehensive overview of recent advances on Sias, and addresses future challenges regarding their functions, applications, and production.
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Affiliation(s)
- Haiquan Yang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Liping Lu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; College of life Science and Engineering, Northwest Minzu University, Lanzhou 730030, China
| | - Xianzhong Chen
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
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4
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Wang H, Liu L, Cao Q, Mao W, Zhang Y, Qu X, Cai X, Lv Y, Chen H, Xu X, Wang X. Haemophilus parasuis α-2,3-sialyltransferase-mediated lipooligosaccharide sialylation contributes to bacterial pathogenicity. Virulence 2019; 9:1247-1262. [PMID: 30036124 PMCID: PMC6104685 DOI: 10.1080/21505594.2018.1502606] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacterial lipooligosaccharide (LOS) is an important virulence-associated factor, and its sialylation largely confers its ability to mediate cell adhesion, invasion, inflammation, and immune evasion. Here, we investigated the function of the Haemophilus parasuis α-2,3-sialyltransferase gene, lsgB, which determines the terminal sialylation of LOS, by generating a lsgB deletion mutant as well as a complementation strain. Our data indicate a direct effect of lsgB on LOS sialylation and reveal important roles of lsgB in promoting the pathogenicity of H. parasuis, including adhesion to and invasion of porcine cells in vitro, bacterial load and survival in vivo, as well as a contribution to serum resistance. These observations highlight the function of lsgB in mediating LOS sialylation and more importantly its role in H. parasuis infection. These findings provide a more profound understanding of the pathogenic mechanism of this disease-causing bacterium.
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Affiliation(s)
- Huan Wang
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China
| | - Lu Liu
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China
| | - Qi Cao
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China
| | - Weiting Mao
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China
| | - Yage Zhang
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China
| | - Xinyi Qu
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China
| | - Xuwang Cai
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , China
| | - Yujin Lv
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China.,d College of Veterinary Medicine , Henan University of Animal Husbandry and Economy , Zhengzhou , China
| | - Huanchun Chen
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , China
| | - Xiaojuan Xu
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , China
| | - Xiangru Wang
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , China
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5
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Wratil PR, Horstkorte R, Reutter W. Metabolic Glycoengineering with N-Acyl Side Chain Modified Mannosamines. Angew Chem Int Ed Engl 2016; 55:9482-512. [PMID: 27435524 DOI: 10.1002/anie.201601123] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Indexed: 12/14/2022]
Abstract
In metabolic glycoengineering (MGE), cells or animals are treated with unnatural derivatives of monosaccharides. After entering the cytosol, these sugar analogues are metabolized and subsequently expressed on newly synthesized glycoconjugates. The feasibility of MGE was first discovered for sialylated glycans, by using N-acyl-modified mannosamines as precursor molecules for unnatural sialic acids. Prerequisite is the promiscuity of the enzymes of the Roseman-Warren biosynthetic pathway. These enzymes were shown to tolerate specific modifications of the N-acyl side chain of mannosamine analogues, for example, elongation by one or more methylene groups (aliphatic modifications) or by insertion of reactive groups (bioorthogonal modifications). Unnatural sialic acids are incorporated into glycoconjugates of cells and organs. MGE has intriguing biological consequences for treated cells (aliphatic MGE) and offers the opportunity to visualize the topography and dynamics of sialylated glycans in vitro, ex vivo, and in vivo (bioorthogonal MGE).
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Affiliation(s)
- Paul R Wratil
- Institut für Laboratoriumsmedizin, Klinische Chemie und Pathobiochemie, Charité-Universitätsmedizin Berlin, Arnimallee 22, 14195, Berlin, Germany.
| | - Rüdiger Horstkorte
- Institut für Physiologische Chemie, Martin-Luther-Universität Halle-Wittenberg, Hollystrasse 1, 06114, Halle, Germany.
| | - Werner Reutter
- Institut für Laboratoriumsmedizin, Klinische Chemie und Pathobiochemie, Charité-Universitätsmedizin Berlin, Arnimallee 22, 14195, Berlin, Germany
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6
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Wratil PR, Horstkorte R, Reutter W. Metabolisches Glykoengineering mitN-Acyl-Seiten- ketten-modifizierten Mannosaminen. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201601123] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Paul R. Wratil
- Institut für Laboratoriumsmedizin, Klinische Chemie und Pathobiochemie; Charité - Universitätsmedizin Berlin; Arnimallee 22 14195 Berlin Deutschland
| | - Rüdiger Horstkorte
- Institut für Physiologische Chemie; Martin-Luther-Universität Halle-Wittenberg; Hollystraße 1 06114 Halle Deutschland
| | - Werner Reutter
- Institut für Laboratoriumsmedizin, Klinische Chemie und Pathobiochemie; Charité - Universitätsmedizin Berlin; Arnimallee 22 14195 Berlin Deutschland
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7
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Saeui CT, Urias E, Liu L, Mathew MP, Yarema KJ. Metabolic glycoengineering bacteria for therapeutic, recombinant protein, and metabolite production applications. Glycoconj J 2015; 32:425-41. [PMID: 25931032 DOI: 10.1007/s10719-015-9583-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/16/2015] [Accepted: 03/19/2015] [Indexed: 12/12/2022]
Abstract
Metabolic glycoengineering is a specialization of metabolic engineering that focuses on using small molecule metabolites to manipulate biosynthetic pathways responsible for oligosaccharide and glycoconjugate production. As outlined in this article, this technique has blossomed in mammalian systems over the past three decades but has made only modest progress in prokaryotes. Nevertheless, a sufficient foundation now exists to support several important applications of metabolic glycoengineering in bacteria based on methods to preferentially direct metabolic intermediates into pathways involved in lipopolysaccharide, peptidoglycan, teichoic acid, or capsule polysaccharide production. An overview of current applications and future prospects for this technology are provided in this report.
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Affiliation(s)
- Christopher T Saeui
- Department of Biomedical Engineering and the Translational Tissue Engineering Center, The Johns Hopkins University, Baltimore, MD, USA
| | - Esteban Urias
- Department of Biomedical Engineering and the Translational Tissue Engineering Center, The Johns Hopkins University, Baltimore, MD, USA
| | - Lingshu Liu
- Department of Biomedical Engineering and the Translational Tissue Engineering Center, The Johns Hopkins University, Baltimore, MD, USA
| | - Mohit P Mathew
- Department of Biomedical Engineering and the Translational Tissue Engineering Center, The Johns Hopkins University, Baltimore, MD, USA
| | - Kevin J Yarema
- Department of Biomedical Engineering and the Translational Tissue Engineering Center, The Johns Hopkins University, Baltimore, MD, USA.
- Translational Tissue Engineering Center, The Johns Hopkins University, 5029 Robert H. & Clarice Smith Building, 400 North Broadway, Baltimore, MD, 21231, USA.
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8
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Tan E, Almaraz RT, Khanna HS, Du J, Yarema KJ. Experimental Design Considerations for In Vitro Non-Natural Glycan Display via Metabolic Oligosaccharide Engineering. ACTA ACUST UNITED AC 2013; 2:171-94. [PMID: 23839968 DOI: 10.1002/9780470559277.ch100059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Metabolic oligosaccharide engineering (MOE) refers to a technique where non-natural monosaccharide analogs are introduced into living biological systems. Once inside a cell, these compounds intercept a targeted biosynthetic glycosylation pathway and in turn are metabolically incorporated into cell-surface-displayed oligosaccharides where they can modulate a host of biological activities or be exploited as "tags" for bio-orthogonal and chemoselective ligation reactions. Undertaking a MOE experiment can be a daunting task based on the growing repertoire of analogs now available and the ever increasing number of metabolic pathways that can be targeted; therefore, a major emphasis of this article is to describe a general approach for analog design and selection and then provide protocols to ensure safe and efficacious analog usage by cells. Once cell-surface glycans have been successfully remodeled by MOE methodology, the stage is set for probing changes to the myriad cellular responses modulated by these versatile molecules. Curr. Protoc. Chem. Biol. 2:171-194 © 2010 by John Wiley & Sons, Inc.
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Affiliation(s)
- Elaine Tan
- Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, Maryland
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9
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Sialic acid metabolism and sialyltransferases: natural functions and applications. Appl Microbiol Biotechnol 2012; 94:887-905. [PMID: 22526796 DOI: 10.1007/s00253-012-4040-1] [Citation(s) in RCA: 194] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 03/16/2012] [Accepted: 03/16/2012] [Indexed: 12/17/2022]
Abstract
Sialic acids are a family of negatively charged monosaccharides which are commonly presented as the terminal residues in glycans of the glycoconjugates on eukaryotic cell surface or as components of capsular polysaccharides or lipooligosaccharides of some pathogenic bacteria. Due to their important biological and pathological functions, the biosynthesis, activation, transfer, breaking down, and recycle of sialic acids are attracting increasing attention. The understanding of the sialic acid metabolism in eukaryotes and bacteria leads to the development of metabolic engineering approaches for elucidating the important functions of sialic acid in mammalian systems and for large-scale production of sialosides using engineered bacterial cells. As the key enzymes in biosynthesis of sialylated structures, sialyltransferases have been continuously identified from various sources and characterized. Protein crystal structures of seven sialyltransferases have been reported. Wild-type sialyltransferases and their mutants have been applied with or without other sialoside biosynthetic enzymes for producing complex sialic acid-containing oligosaccharides and glycoconjugates. This mini-review focuses on current understanding and applications of sialic acid metabolism and sialyltransferases.
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10
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Sialylation of lipooligosaccharides is dispensable for the virulence of Haemophilus ducreyi in humans. Infect Immun 2011; 80:679-87. [PMID: 22144477 DOI: 10.1128/iai.05826-11] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Sialylated glycoconjugates on the surfaces of mammalian cells play important roles in intercellular communication and self-recognition. The sialic acid preferentially expressed in human tissues is N-acetylneuraminic acid (Neu5Ac). In a process called molecular mimicry, many bacterial pathogens decorate their cell surface glycolipids with Neu5Ac. Incorporation of Neu5Ac into bacterial glycolipids promotes bacterial interactions with host cell receptors called Siglecs. These interactions affect bacterial adherence, resistance to serum killing and phagocytosis, and innate immune responses. Haemophilus ducreyi, the etiologic agent of chancroid, expresses lipooligosaccharides (LOS) that are highly sialylated. However, an H. ducreyi sialyltransferase (lst) mutant, whose LOS contain reduced levels of Neu5Ac, is fully virulent in human volunteers. Recently, a second sialyltransferase gene (Hd0053) was discovered in H. ducreyi, raising the possibility that Hd0053 compensated for the loss of lst during human infection. CMP-Neu5Ac is the obligate nucleotide sugar donor for all bacterial sialyltransferases; LOS derived from an H. ducreyi CMP-Neu5Ac synthetase (neuA) mutant has no detectable Neu5Ac. Here, we compared an H. ducreyi neuA mutant to its wild-type parent in several models of pathogenesis. In human inoculation experiments, the neuA mutant formed papules and pustules at rates that were no different than those of its parent. When grown in media with and without Neu5Ac supplementation, the neuA mutant and its parent had similar phenotypes in bactericidal, macrophage uptake, and dendritic cell activation assays. Although we cannot preclude a contribution of LOS sialylation to ulcerative disease, these data strongly suggest that sialylation of LOS is dispensable for H. ducreyi pathogenesis in humans.
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Thon V, Lau K, Yu H, Tran BK, Chen X. PmST2: a novel Pasteurella multocida glycolipid α2-3-sialyltransferase. Glycobiology 2011; 21:1206-16. [PMID: 21515586 DOI: 10.1093/glycob/cwr054] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Pasteurella multocida (Pm) is a multi-species pathogen that causes diseases in animals and humans. Sialyltransferase activity has been detected in multiple Pm strains and sialylation has been shown to be important for the pathogenesis of Pm. Three putative sialyltransferase genes have been identified in Pm genomic strain Pm70. We have reported previously that a Pm0188 gene homolog in Pm strain P-1059 (ATCC 15742) encodes a multifunctional sialyltransferase (PmST1). We demonstrate here that while PmST1 prefers to use oligosaccharides as acceptors, PmST2 encoded by the Pm0508 gene homolog in the same Pm strain is a novel glycolipid α2-3-sialyltransferase that prefers to use lactosyl lipids as acceptor substrates. PmST2 and PmST1 thus complement each other for an efficient synthesis of α2-3-linked sialosides with or without lipid portion. In addition, β1-4-linked galactosyl lipids are better PmST2 substrates than β1-3-linked galactosyl lipids. PmST2 has been used successfully in the preparative scale synthesis of sialyllactosyl sphingosine (lyso-GM3), which is an important glycolipid and an intermediate for synthesizing more complex glycolipids such as gangliosides.
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Affiliation(s)
- Vireak Thon
- Department of Chemistry, University of California, Davis, CA 95616, USA
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12
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Nelson JW, Chamessian AG, McEnaney PJ, Murelli RP, Kazmiercak BI, Spiegel DA, Spiegel DA. A biosynthetic strategy for re-engineering the Staphylococcus aureus cell wall with non-native small molecules. ACS Chem Biol 2010; 5:1147-55. [PMID: 20923200 DOI: 10.1021/cb100195d] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Staphylococcus aureus (S. aureus) is a Gram-positive bacterial pathogen that has emerged as a major public health threat. Here we report that the cell wall of S. aureus can be covalently re-engineered to contain non-native small molecules. This process makes use of endogenous levels of the bacterial enzyme sortase A (SrtA), which ordinarily functions to incorporate proteins into the bacterial cell wall. Thus, incubation of wild-type bacteria with rationally designed SrtA substrates results in covalent incorporation of functional molecular handles (fluorescein, biotin, and azide) into cell wall peptidoglycan. These conclusions are supported by data obtained through a variety of experimental techniques (epifluorescence and electron microscopy, biochemical extraction, and mass spectrometry), and cell-wall-incorporated azide was exploited as a chemical handle to perform an azide-alkyne cycloaddition reaction on the bacterial cell surface. This report represents the first example of cell wall engineering of S. aureus or any other pathogenic Gram-positive bacteria and has the potential for widespread utility.
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Affiliation(s)
- James W. Nelson
- Department of Chemistry, Yale University, New Haven, Connecticut 06520
| | | | | | - Ryan P. Murelli
- Department of Chemistry, Yale University, New Haven, Connecticut 06520
| | - Barbara I. Kazmiercak
- Department of Medicine (Infectious Diseases), Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut 06520
| | - David A. Spiegel
- Department of Chemistry, Yale University, New Haven, Connecticut 06520
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13
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Taylor RE, Gregg CJ, Padler-Karavani V, Ghaderi D, Yu H, Huang S, Sorensen RU, Chen X, Inostroza J, Nizet V, Varki A. Novel mechanism for the generation of human xeno-autoantibodies against the nonhuman sialic acid N-glycolylneuraminic acid. ACTA ACUST UNITED AC 2010; 207:1637-46. [PMID: 20624889 PMCID: PMC2916132 DOI: 10.1084/jem.20100575] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The nonhuman sialic acid N-glycolylneuraminic acid (Neu5Gc) is metabolically incorporated into human tissues from certain mammalian-derived foods, and this occurs in the face of an anti-Neu5Gc “xeno-autoantibody” response. Given evidence that this process contributes to chronic inflammation in some diseases, it is important to understand when and how these antibodies are generated in humans. We show here that human anti-Neu5Gc antibodies appear during infancy and correlate with weaning and exposure to dietary Neu5Gc. However, dietary Neu5Gc alone cannot elicit anti-Neu5Gc antibodies in mice with a humanlike Neu5Gc deficiency. Other postnatally appearing anti-carbohydrate antibodies are likely induced by bacteria expressing these epitopes; however, no microbe is known to synthesize Neu5Gc. Here, we show that trace exogenous Neu5Gc can be incorporated into cell surface lipooligosaccharides (LOS) of nontypeable Haemophilus influenzae (NTHi), a human-specific commensal/pathogen. Indeed, infant anti-Neu5Gc antibodies appear coincident with antibodies against NTHi. Furthermore, NTHi that express Neu5Gc-containing LOS induce anti-Neu5Gc antibodies in Neu5Gc-deficient mice, without added adjuvant. Finally, Neu5Gc from baby food is taken up and expressed by NTHi. As the flora residing in the nasopharynx of infants can be in contact with ingested food, we propose a novel model for how NTHi and dietary Neu5Gc cooperate to generate anti-Neu5Gc antibodies in humans.
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Affiliation(s)
- Rachel E Taylor
- Department of Medicine, Skaggs School of Pharmacy and PharmaceuticalSciences, University of California, San Diego, La Jolla, CA 92093, USA
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14
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Tiralongo J, Wohlschlager T, Tiralongo E, Kiefel MJ. Inhibition of Aspergillus fumigatus conidia binding to extracellular matrix proteins by sialic acids: a pH effect? Microbiology (Reading) 2009; 155:3100-3109. [DOI: 10.1099/mic.0.026997-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Infection by Aspergillus fumigatus, which causes the life-threatening disease invasive aspergillosis, begins with the inhalation of conidia that adhere to and germinate in the lung. Previous studies have shown that A. fumigatus conidia express high levels of the negatively charged 9-carbon sugar sialic acid, and that sialic acid appears to mediate the binding of A. fumigatus conidia to basal lamina proteins. However, despite the ability of sialic acid to inhibit adherence of A. fumigatus conidia, the exact mechanism by which this binding occurs remains unresolved. Utilizing various free sialic acids and other carbohydrates, sialic acid derivatives, sialoglycoconjugates, glycoproteins, α-keto acid related compounds and amino acids we have found that the binding of A. fumigatus conidia to type IV collagen and fibrinogen was inhibited by (i) glycoproteins (in a sialic acid-independent manner), and (ii) free sialic acids, glucuronic acid and α-keto acid related compounds. However, inhibition by the latter was found to be the result of a shift in pH from neutral (pH 7.4) to acidic (less than pH 4.6) induced by the relatively high concentrations of free sialic acids, glucuronic acid and α-keto acid related compounds used in the binding assays. This suggests that previous reports describing inhibition of A. fumigatus conidia binding by free sialic acid may actually be due to a pH shift similar to that shown here. As previously reported, we found that A. fumigatus conidia express only N-acetylneuraminic acid, the most common sialic acid found in nature. However, A. fumigatus appears to do so by an alternative mechanism to that seen in other organisms. We report here that A. fumigatus (i) does not incorporate sialic acid obtained from the environment, (ii) does not synthesize and incorporate sialic acid from exogenous N-acetylmannosamine, and (iii) lacks homologues of known sialic acid biosynthesizing enzymes.
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Affiliation(s)
- Joe Tiralongo
- Institute for Glycomics, Gold Coast Campus, Griffith University, QLD 4222, Australia
| | - Therese Wohlschlager
- Institute for Glycomics, Gold Coast Campus, Griffith University, QLD 4222, Australia
| | - Evelin Tiralongo
- School of Pharmacy, Gold Coast Campus, Griffith University, QLD 4222, Australia
| | - Milton J. Kiefel
- Institute for Glycomics, Gold Coast Campus, Griffith University, QLD 4222, Australia
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15
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Du J, Meledeo MA, Wang Z, Khanna HS, Paruchuri VDP, Yarema KJ. Metabolic glycoengineering: sialic acid and beyond. Glycobiology 2009; 19:1382-401. [PMID: 19675091 DOI: 10.1093/glycob/cwp115] [Citation(s) in RCA: 236] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This report provides a perspective on metabolic glycoengineering methodology developed over the past two decades that allows natural sialic acids to be replaced with chemical variants in living cells and animals. Examples are given demonstrating how this technology provides the glycoscientist with chemical tools that are beginning to reproduce Mother Nature's control over complex biological systems - such as the human brain - through subtle modifications in sialic acid chemistry. Several metabolic substrates (e.g., ManNAc, Neu5Ac, and CMP-Neu5Ac analogs) can be used to feed flux into the sialic acid biosynthetic pathway resulting in numerous - and sometime quite unexpected - biological repercussions upon nonnatural sialoside display in cellular glycans. Once on the cell surface, ketone-, azide-, thiol-, or alkyne-modified glycans can be transformed with numerous ligands via bioorthogonal chemoselective ligation reactions, greatly increasing the versatility and potential application of this technology. Recently, sialic acid glycoengineering methodology has been extended to other pathways with analog incorporation now possible in surface-displayed GalNAc and fucose residues as well as nucleocytoplasmic O-GlcNAc-modified proteins. Finally, recent efforts to increase the "druggability" of sugar analogs used in metabolic glycoengineering, which have resulted in unanticipated "scaffold-dependent" activities, are summarized.
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Affiliation(s)
- Jian Du
- Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA
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16
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Sialic acid catabolism confers a competitive advantage to pathogenic vibrio cholerae in the mouse intestine. Infect Immun 2009; 77:3807-16. [PMID: 19564383 DOI: 10.1128/iai.00279-09] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Sialic acids comprise a family of nine-carbon ketosugars that are ubiquitous on mammalian mucous membranes. However, sialic acids have a limited distribution among Bacteria and are confined mainly to pathogenic and commensal species. Vibrio pathogenicity island 2 (VPI-2), a 57-kb region found exclusively among pathogenic strains of Vibrio cholerae, contains a cluster of genes (nan-nag) putatively involved in the scavenging (nanH), transport (dctPQM), and catabolism (nanA, nanE, nanK, and nagA) of sialic acid. The capacity to utilize sialic acid as a carbon and energy source might confer an advantage to V. cholerae in the mucus-rich environment of the gut, where sialic acid availability is extensive. In this study, we show that V. cholerae can utilize sialic acid as a sole carbon source. We demonstrate that the genes involved in the utilization of sialic acid are located within the nan-nag region of VPI-2 by complementation of Escherichia coli mutants and gene knockouts in V. cholerae N16961. We show that nanH, dctP, nanA, and nanK are highly expressed in V. cholerae grown on sialic acid. By using the infant mouse model of infection, we show that V. cholerae DeltananA strain SAM1776 is defective in early intestinal colonization stages. In addition, SAM1776 shows a decrease in the competitive index in colonization-competition assays comparing the mutant strain with both O1 El Tor and classical strains. Our data indicate an important relationship between the catabolism of sialic acid and bacterial pathogenesis, stressing the relevance of the utilization of the resources found in the host's environment.
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17
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Tatum FM, Tabatabai LB, Briggs RE. Sialic acid uptake is necessary for virulence of Pasteurella multocida in turkeys. Microb Pathog 2009; 46:337-44. [PMID: 19366625 DOI: 10.1016/j.micpath.2009.04.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Revised: 03/27/2009] [Accepted: 04/02/2009] [Indexed: 10/20/2022]
Abstract
Many pathogenic bacteria employ systems to incorporate sialic acid into their membranes as a means of protection against host defense mechanisms. In Pasteurella multocida, an opportunistic pathogen which causes diseases of economic importance in a wide range of animal species, sialic acid uptake plays a role in a mouse model of systemic pasteurellosis. To further investigate the importance of sialic acid uptake in pathogenesis, sialic acid uptake mutants of an avian strain of P. multocida P-1059 (A:3) were constructed, characterized, and an in-frame sialic acid uptake deletion mutant was assessed for virulence in turkeys. Inactivation of sialic acid uptake resulted in a high degree of attenuation when turkeys were challenged either intranasally or intravenously. Resistance of the sialic acid uptake mutant to killing by turkey serum complement was similar to that of the parent, suggesting other mechanisms are responsible for attenuation of virulence in turkeys.
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Affiliation(s)
- Fred M Tatum
- US Department of Agriculture, Respiratory Diseases of Livestock Unit, National Animal Disease Center, Agricultural Research Service, Ames, IA 50010, USA
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18
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Harvey DJ. Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update covering the period 2001-2002. MASS SPECTROMETRY REVIEWS 2008; 27:125-201. [PMID: 18247413 DOI: 10.1002/mas.20157] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
This review is the second update of the original review on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates that was published in 1999. It covers fundamental aspects of the technique as applied to carbohydrates, fragmentation of carbohydrates, studies of specific carbohydrate types such as those from plant cell walls and those attached to proteins and lipids, studies of glycosyl-transferases and glycosidases, and studies where MALDI has been used to monitor products of chemical synthesis. Use of the technique shows a steady annual increase at the expense of older techniques such as FAB. There is an increasing emphasis on its use for examination of biological systems rather than on studies of fundamental aspects and method development and this is reflected by much of the work on applications appearing in tabular form.
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Affiliation(s)
- David J Harvey
- Department of Biochemistry, Oxford Glycobiology Institute, South Parks Road, Oxford OX1 3QU, UK.
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19
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Li Y, Sun M, Huang S, Yu H, Chokhawala HA, Thon V, Chen X. The Hd0053 gene of Haemophilus ducreyi encodes an alpha2,3-sialyltransferase. Biochem Biophys Res Commun 2007; 361:555-60. [PMID: 17662691 PMCID: PMC2084346 DOI: 10.1016/j.bbrc.2007.07.063] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2007] [Accepted: 07/12/2007] [Indexed: 11/23/2022]
Abstract
Haemophilus ducreyi is a Gram-negative bacterium that causes chancroid, a sexually transmitted genital ulcer disease. Different lipooligosaccharide (LOS) structures have been identified from H. ducreyi strain 35000, including those sialylated glycoforms. Surface LOS of H. ducreyi is considered an important virulence factor that is involved in ulcer formation, cell adhesion, and invasion of host tissue. Gene Hd0686 of H. ducreyi, designated lst (for lipooligosaccharide sialyltransferase), was identified to encode an alpha2,3-sialyltransferase that is important for the formation of sialylated LOS. Here, we show that Hd0053 of H. ducreyi genomic strain 35000HP, the third member of the glycosyltransferase family 80 (GT80), also encodes an alpha2,3-sialyltransferase that may be important for LOS sialylation.
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Affiliation(s)
- Yanhong Li
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA
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20
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Post DMB, Mungur R, Gibson BW, Munson RS. Identification of a novel sialic acid transporter in Haemophilus ducreyi. Infect Immun 2005; 73:6727-35. [PMID: 16177350 PMCID: PMC1230923 DOI: 10.1128/iai.73.10.6727-6735.2005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Haemophilus ducreyi, the causative agent of chancroid, produces a lipooligosaccharide (LOS) which terminates in N-acetyllactosamine. This glycoform can be further extended by the addition of a single sialic acid residue to the terminal galactose moiety. H. ducreyi does not synthesize sialic acid, which must be acquired from the host during infection or from the culture medium when the bacteria are grown in vitro. However, H. ducreyi does not have genes that are highly homologous to the genes encoding known bacterial sialic acid transporters. In this study, we identified the sialic acid transporter by screening strains in a library of random transposon mutants for those mutants that were unable to add sialic acid to N-acetyllactosamine-containing LOS. Mutants that reacted with the monoclonal antibody 3F11, which recognizes the terminal lactosamine structure, and lacked reactivity with the lectin Maackia amurensis agglutinin, which recognizes alpha2,3-linked sialic acid, were further characterized to demonstrate that they produced a N-acetyllactosamine-containing LOS by silver-stained sodium dodecyl sulfate-polyacrylamide gel electrophoresis and mass spectrometric analyses. The genes interrupted in these mutants were mapped to a four-gene cluster with similarity to genes encoding bacterial ABC transporters. Uptake assays using radiolabeled sialic acid confirmed that the mutants were unable to transport sialic acid. This study is the first report of bacteria using an ABC transporter for sialic acid uptake.
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21
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Steenbergen SM, Lichtensteiger CA, Caughlan R, Garfinkle J, Fuller TE, Vimr ER. Sialic Acid metabolism and systemic pasteurellosis. Infect Immun 2005; 73:1284-94. [PMID: 15731025 PMCID: PMC1064920 DOI: 10.1128/iai.73.3.1284-1294.2005] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pasteurella multocida subsp. multocida is a commensal and opportunistic pathogen of food animals, wildlife, and pets and a zoonotic cause of human infection arising from contacts with these animals. Here, an investigation of multiple serotype A strains demonstrated the occurrence of membrane sialyltransferase. Although P. multocida lacks the genes for the two earliest steps in de novo sialic acid synthesis, adding sialic acid to the growth medium resulted in uptake, activation, and subsequent transfer of sialic acid to a membrane acceptor resembling lipooligosaccharide. Two candidate-activating enzymes with homology to Escherichia coli cytidine 5'-monophospho-N-acetylneuraminate synthetase were overproduced as histidine-tagged polypeptides. The synthetase encoded by pm0187 was at least 37 times more active than the pm1710 gene product, suggesting pm0187 encodes the primary sialic acid cytidylyltransferase in P. multocida. A sialate aldolase (pm1715) mutant unable to initiate dissimilation of internalized sialic acid was not attenuated in the CD-1 mouse model of systemic pasteurellosis, indicating that the nutritional function of sialate catabolism is not required for systemic disease. In contrast, the attenuation of a sialate uptake-deficient mutant supports the essential role in pathogenesis of a sialylation mechanism that is dependent on an environmental (host) supply of sialic acid. The combined results provide the first direct evidence of sialylation by a precursor scavenging mechanism in pasteurellae and of a potential tripartite ATP-independent periplasmic sialate transporter in any species.
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Affiliation(s)
- Susan M Steenbergen
- Laboratory of Sialobiology, Department of Pathobiology, Universityof Illinois at Urbana-Champaign, Urbana, IL 61802, USA
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22
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Sundaram A, Pitts L, Muhammad K, Wu J, Betenbaugh M, Woodard R, Vann W. Characterization of N-acetylneuraminic acid synthase isoenzyme 1 from Campylobacter jejuni. Biochem J 2005; 383:83-9. [PMID: 15200387 PMCID: PMC1134046 DOI: 10.1042/bj20040218] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2004] [Revised: 06/14/2004] [Accepted: 06/16/2004] [Indexed: 11/17/2022]
Abstract
Escherichia coli NeuNAc (N-acetylneuraminic acid) synthase catalyses the condensation of PEP (phosphoenolpyruvate) and ManNAc (N-acetylmannosamine) to form NeuNAc and is encoded by the neuB gene. Campylobacter jejuni has three neuB genes, one of which is very similar to the E. coli neuB gene. We have characterized the C. jejuni neuraminic acid synthase with respect to acylamino sugar specificity and stereochemistry of the PEP condensation. We determined the specificity of C. jejuni NeuNAc synthase for N-acetylmannosamine, N-butanoylmannosamine, N-propionoylmannosamine and N-pentanoylmannosamine. We find that, although this enzyme exhibits similar K(m) values for N-acylmannosamine molecules with different N-acyl groups, the kcat/K(m) values decreased with increasing chain length. NeuNAc synthase is a member of a PEP-utilizing family of enzymes that form oxo acids from PEP and a monosaccharide. This family includes KDO 8-P (2-keto-3-deoxy-D-manno-octulosonate 8-phosphate) synthase and DAH 7-P (2-keto-3-deoxy-D-arabino-heptulosonate 7-phosphate) synthase. Both enzymes catalyse the condensation of the re face of the aldehyde group of the monosaccharide with the si face of the PEP molecule. The C. jejuni NeuNAc synthase catalysed the condensation of Z- and E-[3-2H]PEP with ManNAc, yielding (3S)-3-deutero-NeuNAc and (3R)-3-deutero-NeuNAc respectively. The condensation of Z-[3-F]PEP and ManNAc yielded (3S)-3-fluoro-NeuNAc. Results of our studies suggest that the C. jejuni NeuNAc synthase, similar to KDO 8-P synthase and DAH 7-P synthase, catalyses the condensation of the si face of PEP with the aldehyde sugar. The present study is the first stereochemical analysis of the reaction catalysed by a bacterial NeuNAc synthase.
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Affiliation(s)
- Appavu K. Sundaram
- *Laboratory of Bacterial Toxins, Center for Biologics Evaluation and Research, 8800 Rockville Pike, Bethesda, MD 20892, U.S.A
| | - Lee Pitts
- †Department of Chemical Engineering, Johns Hopkins University, Baltimore, MD, U.S.A
| | - Kamilah Muhammad
- *Laboratory of Bacterial Toxins, Center for Biologics Evaluation and Research, 8800 Rockville Pike, Bethesda, MD 20892, U.S.A
| | - Jing Wu
- ‡Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109-1065, U.S.A
| | - Michael Betenbaugh
- †Department of Chemical Engineering, Johns Hopkins University, Baltimore, MD, U.S.A
| | - Ronald W. Woodard
- ‡Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109-1065, U.S.A
| | - Willie F. Vann
- *Laboratory of Bacterial Toxins, Center for Biologics Evaluation and Research, 8800 Rockville Pike, Bethesda, MD 20892, U.S.A
- To whom correspondence should be addressed (email )
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23
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Goon S, Schilling B, Tullius MV, Gibson BW, Bertozzi CR. Metabolic incorporation of unnatural sialic acids into Haemophilus ducreyi lipooligosaccharides. Proc Natl Acad Sci U S A 2003; 100:3089-94. [PMID: 12615992 PMCID: PMC152251 DOI: 10.1073/pnas.0437851100] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2002] [Accepted: 12/20/2002] [Indexed: 11/18/2022] Open
Abstract
The lipooligosaccharides (LOS) of Haemophilus ducreyi are highly sialylated, a modification that has been implicated in resistance to host defense and in virulence. In previous work, we demonstrated that H. ducreyi scavenges sialic acid from the extracellular milieu and incorporates those residues into LOS. Here we report that H. ducreyi can use unnatural sialic acids bearing elongated N-acyl groups from three to seven carbon atoms in length, resulting in outer membrane presentation of unnatural sialyl-LOS. The unnatural variant comprises approximately 90% of cell surface sialosides when exogenous substrates are added to the media at micromolar concentrations, despite the availability of natural sialic acid in the growth media. Although they represent the majority of cell surface sialosides, analogs with longer N-acyl groups diminish the overall level of LOS sialylation, culminating in complete inhibition of LOS sialylation by N-octanoyl sialic acid. Thus, sialylation of H. ducreyi LOS can be modulated with respect to the structure of the terminal sialic acid residue and the extent to which the LOS acceptor is modified by supplying the bacteria with various sialic acid analogs.
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Affiliation(s)
- Scarlett Goon
- Department of Chemistry and Molecular, Howard Hughes Medical Institute, University of California, Los Angeles, CA 90065, USA
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24
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Inzana TJ, Glindemann G, Cox AD, Wakarchuk W, Howard MD. Incorporation of N-acetylneuraminic acid into Haemophilus somnus lipooligosaccharide (LOS): enhancement of resistance to serum and reduction of LOS antibody binding. Infect Immun 2002; 70:4870-9. [PMID: 12183531 PMCID: PMC128230 DOI: 10.1128/iai.70.9.4870-4879.2002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Haemophilus somnus isolates from cases of thrombotic meningoencephalitis, pneumonia, and other disease sites are capable of undergoing a high rate of phase variation in the oligosaccharide component of their lipooligosaccharides (LOS). In contrast, the LOS of commensal strains isolated from the normal reproductive tract phase vary little or not at all. In addition, the LOS of H. somnus shares conserved epitopes with LOS from Neisseria gonorrhoeae, Haemophilus influenzae, and other species that can incorporate sialic acid into their LOS. We now report that growth of disease isolates of H. somnus with CMP-N-acetylneuraminic acid (CMP-NeuAc) or NeuAc added to the medium resulted in incorporation of NeuAc into the LOS. However, NeuAc was not incorporated into the LOS of commensal isolates and one disease isolate following growth in medium containing CMP-NeuAc or NeuAc. Sialylated LOS was detected by an increase in the molecular size or an increase in the amount of the largest-molecular-size LOS electrophoretic bands, which disappeared following treatment with neuraminidase. Sialylated LOS could also be detected by reactivity with Limax flavus agglutinin lectin, which is specific for sialylated species, by dot blot assay; this reactivity was also reversed by neuraminidase treatment. H. somnus strain 2336 LOS was found to contain some sialic acid when grown in medium lacking CMP-NeuAc or NeuAc, although supplementation enhanced NeuAc incorporation. In contrast strain 738, an LOS phase variant of strain 2336, was less extensively sialylated when the growth medium was supplemented with CMP-NeuAc or NeuAc, as determined by electrophoretic profiles and electrospray mass spectrometry. The sialyltransferase of H. somnus strain 738 was confirmed to preferentially sialylate the Gal(beta)-(1-3)-GlcNAc component of the lacto-N-tetraose structure by capillary electrophoresis assay. Enhanced sialylation of the strain 2336 LOS inhibited the binding of monoclonal antibodies to LOS by enzyme immunoassay and Western blotting. Furthermore, sialylation of the LOS enhanced the resistance of H. somnus to the bactericidal action of antiserum to LOS. Sialylation and increased resistance to killing by normal serum also occurred in a deletion mutant that was deficient in the terminal Gal-GlcNAc disaccharide. LOS sialylation may therefore be an important virulence mechanism to protect H. somnus against the host immune system.
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Affiliation(s)
- Thomas J Inzana
- Center for Molecular Medicine and Infectious Diseases, Virginia Polytechnic Institute & State University, Blacksburg, Virginia 24061-0342, USA.
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25
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Abstract
Most oropharyngeal pathogens express sialic acid units on their surfaces, mimicking the sialyl-rich mucin layer coating epithelial cells and the glycoconjugates present on virtually all host cell surfaces and serum proteins. Unlike the host's cells, which synthesize sialic acids endogenously, several microbial pathogens use truncated sialylation pathways. How microorganisms regulate sialic acid metabolism to ensure an adequate supply of free sugar for surface remodeling is a new area of research interest to basic scientists and those focused on the clinical outcome of the host-pathogen interaction.
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Affiliation(s)
- Eric Vimr
- Division of Microbiology and Immunology, Dept of Pathobiology, University of Illinois at Urbana-Champaign, 2001 South Lincoln Ave, Urbana, IL 61802, USA.
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26
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Tullius MV, Phillips NJ, Scheffler NK, Samuels NM, Munson Jr RS, Hansen EJ, Stevens-Riley M, Campagnari AA, Gibson BW. The lbgAB gene cluster of Haemophilus ducreyi encodes a beta-1,4-galactosyltransferase and an alpha-1,6-DD-heptosyltransferase involved in lipooligosaccharide biosynthesis. Infect Immun 2002; 70:2853-61. [PMID: 12010972 PMCID: PMC128009 DOI: 10.1128/iai.70.6.2853-2861.2002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
All Haemophilus ducreyi strains examined contain a lipooligosaccharide (LOS) consisting of a single but variable branch oligosaccharide that emanates off the first heptose (Hep-I) of a conserved Hep(3)-phosphorylated 3-deoxy-D-manno-octulosonic acid-lipid A core. In a previous report, identification of tandem genes, lbgA and lbgB, that are involved in LOS biosynthesis was described (Stevens et al., Infect. Immun. 65:651-660, 1997). In a separate study, the same gene cluster was identified and the lbgB (losB) gene was found to be required for transfer of the second sugar, D-glycero-D-manno-heptose (DD-Hep), of the major branch structure (Gibson et al., J. Bacteriol. 179:5062-5071, 1997). In this study, we identified the function of the neighboring upstream gene, lbgA, and found that it is necessary for addition of the third sugar in the dominant oligosaccharide branch, a galactose-linked beta1-->4, to the DD-Hep. LOS from an lbgA mutant and an lbgAB double mutant were isolated and were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, carbohydrate analysis, mass spectrometry, and nuclear magnetic resonance spectroscopy. The results showed that the mutant strains synthesize truncated LOS glycoforms that terminate after addition of the first glucose (lbgAB) or the disaccharide DD-Hepalpha1-->6Glcbeta1 (lbgA) that is attached to the heptose core. Both mutants show a significant reduction in the ability to adhere to human keratinocytes. Although minor differences were observed after two-dimensional gel electrophoresis of total proteins from the wild-type and mutant strains, the expression levels of the vast majority of proteins were unchanged, suggesting that the differences in adherence and invasion are due to differences in LOS. These studies add to the mounting evidence for a role of full-length LOS structures in the pathophysiology of H. ducreyi infection.
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Affiliation(s)
- Michael V Tullius
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143-0446, USA
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