1
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Franklin A, Salgueiro VC, Layton AJ, Sullivan R, Mize T, Vázquez-Iniesta L, Benedict ST, Gurcha SS, Anso I, Besra GS, Banzhaf M, Lovering AL, Williams SJ, Guerin ME, Scott NE, Prados-Rosales R, Lowe EC, Moynihan PJ. The mycobacterial glycoside hydrolase LamH enables capsular arabinomannan release and stimulates growth. Nat Commun 2024; 15:5740. [PMID: 38982040 PMCID: PMC11233589 DOI: 10.1038/s41467-024-50051-3] [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: 12/06/2023] [Accepted: 06/26/2024] [Indexed: 07/11/2024] Open
Abstract
Mycobacterial glycolipids are important cell envelope structures that drive host-pathogen interactions. Arguably, the most important are lipoarabinomannan (LAM) and its precursor, lipomannan (LM), which are trafficked from the bacterium to the host via unknown mechanisms. Arabinomannan is thought to be a capsular derivative of these molecules, lacking a lipid anchor. However, the mechanism by which this material is generated has yet to be elucidated. Here, we describe the identification of a glycoside hydrolase family 76 enzyme that we term LamH (Rv0365c in Mycobacterium tuberculosis) which specifically cleaves α-1,6-mannoside linkages within LM and LAM, driving its export to the capsule releasing its phosphatidyl-myo-inositol mannoside lipid anchor. Unexpectedly, we found that the catalytic activity of this enzyme is important for efficient exit from stationary phase cultures, potentially implicating arabinomannan as a signal for growth phase transition. Finally, we demonstrate that LamH is important for M. tuberculosis survival in macrophages.
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Affiliation(s)
- Aaron Franklin
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Vivian C Salgueiro
- Department of Preventive Medicine, Public Health and Microbiology, School of Medicine, Universidad Autonoma de Madrid, Madrid, Spain
| | | | - Rudi Sullivan
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Todd Mize
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Lucía Vázquez-Iniesta
- Department of Preventive Medicine, Public Health and Microbiology, School of Medicine, Universidad Autonoma de Madrid, Madrid, Spain
| | | | | | - Itxaso Anso
- Structural Glycobiology Laboratory, Department of Structural and Molecular Biology, Molecular Biology Institute of Barcelona, Spanish National Research Council, Barcelona Science Park, c/Baldiri Reixac 10-12, Tower R, 08028, Barcelona, Catalonia, Spain
| | - Gurdyal S Besra
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Manuel Banzhaf
- School of Biosciences, University of Birmingham, Birmingham, UK
| | | | - Spencer J Williams
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, Australia
| | - Marcelo E Guerin
- Structural Glycobiology Laboratory, Department of Structural and Molecular Biology; Molecular Biology Institute of Barcelona (IBMB), Spanish National Research Council (CSIC), Barcelona, Catalonia, Spain
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Rafael Prados-Rosales
- Department of Preventive Medicine, Public Health and Microbiology, School of Medicine, Universidad Autonoma de Madrid, Madrid, Spain
| | - Elisabeth C Lowe
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, UK.
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2
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Palčeková Z, De K, Angala SK, Gilleron M, Zuberogoitia S, Gouxette L, Soto-Ojeda M, Gonzalez-Juarrero M, Obregón-Henao A, Nigou J, Wheat WH, Jackson M. Impact of Methylthioxylose Substituents on the Biological Activities of Lipomannan and Lipoarabinomannan in Mycobacterium tuberculosis. ACS Infect Dis 2024; 10:1379-1390. [PMID: 38511206 PMCID: PMC11014759 DOI: 10.1021/acsinfecdis.4c00079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
Two lipoglycans, lipomannan (LM) and lipoarabinomannan (LAM), play various, albeit incompletely defined, roles in the interactions of mycobacteria with the host. Growing evidence points to the modification of LM and LAM with discrete covalent substituents as a strategy used by these bacteria to modulate their biological activities. One such substituent, originally identified in Mycobacterium tuberculosis (Mtb), is a 5-methylthio-d-xylose (MTX) sugar, which accounts for the antioxidative properties of LAM. The widespread distribution of this motif across Mtb isolates from several epidemiologically important lineages have stimulated interest in MTX-modified LAM as a biomarker of tuberculosis infection. Yet, several lines of evidence indicate that MTX may not be restricted to Mtb and that this motif may substitute more acceptors than originally thought. Using a highly specific monoclonal antibody to the MTX capping motif of Mtb LAM, we here show that MTX motifs not only substitute the mannoside caps of LAM but also the mannan core of LM in Mtb. MTX substituents were also found on the LM and LAM of pathogenic, slow-growing nontuberculous mycobacteria. The presence of MTX substituents on the LM and LAM from Mtb enhances the pro-apoptotic properties of both lipoglycans on LPS-stimulated THP-1 macrophages. A comparison of the cytokines and chemokines produced by resting and LPS-activated THP-1 cells upon exposure to MTX-proficient versus MTX-deficient LM further indicates that MTX substituents confer anti-inflammatory properties upon LM. These findings add to our understanding of the glycan-based strategies employed by slow-growing pathogenic mycobacteria to alter the host immune response to infection.
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Affiliation(s)
- Zuzana Palčeková
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Kavita De
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Shiva Kumar Angala
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Martine Gilleron
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Sophie Zuberogoitia
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Lucie Gouxette
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Maritza Soto-Ojeda
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Mercedes Gonzalez-Juarrero
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Andrés Obregón-Henao
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Jérôme Nigou
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - William H. Wheat
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
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3
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Franklin A, Layton AJ, Mize T, Salgueiro VC, Sullivan R, Benedict ST, Gurcha SS, Anso I, Besra GS, Banzhaf M, Lovering AL, Williams SJ, Guerin ME, Scott NE, Prados-Rosales R, Lowe EC, Moynihan PJ. The mycobacterial glycoside hydrolase LamH enables capsular arabinomannan release and stimulates growth. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.26.563968. [PMID: 37961452 PMCID: PMC10634837 DOI: 10.1101/2023.10.26.563968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Mycobacterial glycolipids are important cell envelope structures that drive host-pathogen interactions. Arguably, the most important amongst these are lipoarabinomannan (LAM) and its precursor, lipomannan (LM), which are both trafficked out of the bacterium to the host via unknown mechanisms. An important class of exported LM/LAM is the capsular derivative of these molecules which is devoid of its lipid anchor. Here, we describe the identification of a glycoside hydrolase family 76 enzyme that we term LamH which specifically cleaves α-1,6-mannoside linkages within LM and LAM, driving its export to the capsule releasing its phosphatidyl-myo-inositol mannoside lipid anchor. Unexpectedly, we found that the catalytic activity of this enzyme is important for efficient exit from stationary phase cultures where arabinomannan acts as a signal for growth phase transition. Finally, we demonstrate that LamH is important for Mycobacterium tuberculosis survival in macrophages. These data provide a new framework for understanding the biological role of LAM in mycobacteria.
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Affiliation(s)
- Aaron Franklin
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Abigail J. Layton
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Todd Mize
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Vivian C. Salgueiro
- Department of Preventive Medicine, Public Health and Microbiology. School of Medicine. Universidad Autonoma de Madrid, 28029 Madrid, Spain
| | - Rudi Sullivan
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Samuel T. Benedict
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Sudagar S. Gurcha
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Itxaso Anso
- Structural Glycobiology Laboratory, Biocruces Health Research Institute, Barakaldo, Bizkaia, 48903, Spain
| | - Gurdyal S. Besra
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Manuel Banzhaf
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Andrew L. Lovering
- School of Biosciences, University of Birmingham, Birmingham, U.K., B15 2TT
| | - Spencer J. Williams
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Marcelo E. Guerin
- Structural Glycobiology Laboratory, Department of Structural and Molecular Biology; Molecular Biology Institute of Barcelona (IBMB), Spanish National Research Council (CSIC), Barcelona Science Park, c/Baldiri Reixac 4-8, Tower R, 08028 Barcelona, Catalonia, Spain
| | - Nichollas E. Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne 3000, Australia
| | - Rafael Prados-Rosales
- Department of Preventive Medicine, Public Health and Microbiology. School of Medicine. Universidad Autonoma de Madrid, 28029 Madrid, Spain
| | - Elisabeth C. Lowe
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, U.K., NE2 4HH
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4
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Liu Y, Chen T, Zhu Y, Furey A, Lowary TL, Chan J, Bournazos S, Ravetch JV, Achkar JM. Features and protective efficacy of human mAbs targeting Mycobacterium tuberculosis arabinomannan. JCI Insight 2023; 8:e167960. [PMID: 37733444 PMCID: PMC10619501 DOI: 10.1172/jci.insight.167960] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 09/06/2023] [Indexed: 09/23/2023] Open
Abstract
A better understanding of the epitopes most relevant for antibody-mediated protection against tuberculosis (TB) remains a major knowledge gap. We have shown that human polyclonal IgG against the Mycobacterium tuberculosis (M. tuberculosis) surface glycan arabinomannan (AM) and related lipoarabinomannan (LAM) is protective against TB. To investigate the impact of AM epitope recognition and Fcγ receptor (FcγR) binding on antibody functions against M. tuberculosis, we isolated a high-affinity human monoclonal antibody (mAb; P1AM25) against AM and showed its binding to oligosaccharide (OS) motifs we previously found to be associated with in vitro functions of human polyclonal anti-AM IgG. Human IgG1 P1AM25, but not 2 other high-affinity human IgG1 anti-AM mAbs reactive with different AM OS motifs, enhanced M. tuberculosis phagocytosis by macrophages and reduced intracellular growth in an FcγR-dependent manner. P1AM25 in murine IgG2a, but neither murine IgG1 nor a non-FcγR-binding IgG, given intraperitoneally prior to and after aerosolized M. tuberculosis infection, was protective in C57BL/6 mice. Moreover, we demonstrated the protective efficacy of human IgG1 P1AM25 in passive transfer with M. tuberculosis-infected FcγR-humanized mice. These data enhance our knowledge of the important interplay between both antibody epitope specificity and Fc effector functions in the defense against M. tuberculosis and could inform development of vaccines against TB.
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Affiliation(s)
- Yanyan Liu
- Department of Microbiology and Immunology and
| | - Tingting Chen
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Yongqi Zhu
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Aisha Furey
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Todd L. Lowary
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - John Chan
- Public Health Research Institute at the International Center for Public Health, New Jersey Medical School – Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | | | | | - Jacqueline M. Achkar
- Department of Microbiology and Immunology and
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
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5
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Palčeková Z, Obregón-Henao A, De K, Walz A, Lam H, Philp J, Angala SK, Patterson J, Pearce C, Zuberogoitia S, Avanzi C, Nigou J, McNeil M, Muñoz Gutiérrez JF, Gilleron M, Wheat WH, Gonzalez-Juarrero M, Jackson M. Role of succinyl substituents in the mannose-capping of lipoarabinomannan and control of inflammation in Mycobacterium tuberculosis infection. PLoS Pathog 2023; 19:e1011636. [PMID: 37669276 PMCID: PMC10503756 DOI: 10.1371/journal.ppat.1011636] [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: 11/23/2022] [Revised: 09/15/2023] [Accepted: 08/25/2023] [Indexed: 09/07/2023] Open
Abstract
The covalent modification of bacterial (lipo)polysaccharides with discrete substituents may impact their biosynthesis, export and/or biological activity. Whether mycobacteria use a similar strategy to control the biogenesis of its cell envelope polysaccharides and modulate their interaction with the host during infection is unknown despite the report of a number of tailoring substituents modifying the structure of these glycans. Here, we show that discrete succinyl substituents strategically positioned on Mycobacterium tuberculosis (Mtb) lipoarabinomannan govern the mannose-capping of this lipoglycan and, thus, much of the biological activity of the entire molecule. We further show that the absence of succinyl substituents on the two main cell envelope glycans of Mtb, arabinogalactan and lipoarabinomannan, leads to a significant increase of pro-inflammatory cytokines and chemokines in infected murine and human macrophages. Collectively, our results validate polysaccharide succinylation as a critical mechanism by which Mtb controls inflammation.
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Affiliation(s)
- Zuzana Palčeková
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Andrés Obregón-Henao
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Kavita De
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Amanda Walz
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Ha Lam
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Jamie Philp
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Shiva Kumar Angala
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Johnathan Patterson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Camron Pearce
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Sophie Zuberogoitia
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Charlotte Avanzi
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Jérôme Nigou
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Michael McNeil
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Juan F. Muñoz Gutiérrez
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Martine Gilleron
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - William H. Wheat
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Mercedes Gonzalez-Juarrero
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
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6
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Chemical synthesis of oligosaccharides and their application in new drug research. Eur J Med Chem 2023; 249:115164. [PMID: 36758451 DOI: 10.1016/j.ejmech.2023.115164] [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: 12/16/2022] [Revised: 01/16/2023] [Accepted: 01/25/2023] [Indexed: 02/04/2023]
Abstract
Oligosaccharides are the ubiquitous molecules of life. In order to translate human bioglycosylation into clinical applications, homogeneous samples of oligosaccharides and glycoconjugates can be obtained by chemical, enzymatic or other biological methods for systematic studies. However, the structural complexity and diversity of glycans and their conjugates present a major challenge for the synthesis of such molecules. This review summarizes the chemical synthesis methods of oligosaccharides, the application of oligosaccharides in the field of medicinal chemistry according to their related biological activities, and shows the great prospect of oligosaccharides in the field of pharmaceutical chemistry.
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7
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Abstract
Glycans, carbohydrate molecules in the realm of biology, are present as biomedically important glycoconjugates and a characteristic aspect is that their structures in many instances are branched. In determining the primary structure of a glycan, the sugar components including the absolute configuration and ring form, anomeric configuration, linkage(s), sequence, and substituents should be elucidated. Solution state NMR spectroscopy offers a unique opportunity to resolve all these aspects at atomic resolution. During the last two decades, advancement of both NMR experiments and spectrometer hardware have made it possible to unravel carbohydrate structure more efficiently. These developments applicable to glycans include, inter alia, NMR experiments that reduce spectral overlap, use selective excitations, record tilted projections of multidimensional spectra, acquire spectra by multiple receivers, utilize polarization by fast-pulsing techniques, concatenate pulse-sequence modules to acquire several spectra in a single measurement, acquire pure shift correlated spectra devoid of scalar couplings, employ stable isotope labeling to efficiently obtain homo- and/or heteronuclear correlations, as well as those that rely on dipolar cross-correlated interactions for sequential information. Refined computer programs for NMR spin simulation and chemical shift prediction aid the structural elucidation of glycans, which are notorious for their limited spectral dispersion. Hardware developments include cryogenically cold probes and dynamic nuclear polarization techniques, both resulting in enhanced sensitivity as well as ultrahigh field NMR spectrometers with a 1H NMR resonance frequency higher than 1 GHz, thus improving resolution of resonances. Taken together, the developments have made and will in the future make it possible to elucidate carbohydrate structure in great detail, thereby forming the basis for understanding of how glycans interact with other molecules.
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Affiliation(s)
- Carolina Fontana
- Departamento
de Química del Litoral, CENUR Litoral Norte, Universidad de la República, Paysandú 60000, Uruguay
| | - Göran Widmalm
- Department
of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden,
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8
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Corrigan DT, Ishida E, Chatterjee D, Lowary TL, Achkar JM. Monoclonal antibodies to lipoarabinomannan/arabinomannan - characteristics and implications for tuberculosis research and diagnostics. Trends Microbiol 2023; 31:22-35. [PMID: 35918247 PMCID: PMC9771891 DOI: 10.1016/j.tim.2022.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 12/24/2022]
Abstract
Antibodies to the mycobacterial surface lipoglycan lipoarabinomannan (LAM) and its related capsular polysaccharide arabinomannan (AM) are increasingly important for investigations focused on both understanding mechanisms of protection against Mycobacterium tuberculosis (Mtb) and developing next-generation point-of-care tuberculosis (TB) diagnostics. We provide here an overview of the growing pipeline of monoclonal antibodies (mAbs) to LAM/AM. Old and new methodologies for their generation are reviewed and we outline and discuss their glycan epitope specificity and other features with implications for the TB field.
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Affiliation(s)
- Devin T Corrigan
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA; Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Elise Ishida
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Delphi Chatterjee
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Todd L Lowary
- Institute of Biological Chemistry, Academia Sinica, Nangang Taipei, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Jacqueline M Achkar
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA; Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA.
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9
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Xu H, Schaugaard RN, Li J, Schlegel HB, Nguyen HM. Stereoselective 1,2- cis Furanosylations Catalyzed by Phenanthroline. J Am Chem Soc 2022; 144:7441-7456. [PMID: 35413194 DOI: 10.1021/jacs.2c02063] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Stereoselective formation of the 1,2-cis furanosidic linkage, a motif of many biologically relevant oligosaccharides and polysaccharides, remains an important synthetic challenge. We herein report a new stereoselective 1,2-cis furanosylation method promoted by phenanthroline catalysts under mild and operationally simple conditions. NMR experiments and density functional theory calculations support an associative mechanism in which the rate-determining step occurs from an inverted displacement of the faster-reacting phenanthrolinium ion intermediate with an alcohol nucleophile. The phenanthroline catalysis system is applicable to a number of furanosyl bromide donors to provide the challenging 1,2-cis substitution products in good yield with high anomeric selectivities. While arabinofuranosyl bromide provides β-1,2-cis products, xylo- and ribofuranosyl bromides favor α-1,2-cis products.
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Affiliation(s)
- Hengfu Xu
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Richard N Schaugaard
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Jiayi Li
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - H Bernhard Schlegel
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Hien M Nguyen
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
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10
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De P, Amin AG, Flores D, Simpson A, Dobos K, Chatterjee D. Structural implications of lipoarabinomannan glycans from global clinical isolates in diagnosis of Mycobacterium tuberculosis infection. J Biol Chem 2021; 297:101265. [PMID: 34600887 PMCID: PMC8531672 DOI: 10.1016/j.jbc.2021.101265] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 09/22/2021] [Accepted: 09/28/2021] [Indexed: 12/28/2022] Open
Abstract
In Mycobacterium tuberculosis (Mtb), surface-exposed Lipoarabinomannan (LAM) is a key determinant of immunogenicity, yet its intrinsic heterogeneity confounds typical structure–function analysis. Recently, LAM gained a strong foothold as a validated marker for active tuberculosis (TB) infection and has shown great potential in new diagnostic efforts. However, no efforts have yet been made to model or evaluate the impact of mixed polyclonal Mtb infections (infection with multiple strains) on TB diagnostic procedures other than antibiotic susceptibility testing. Here, we selected three TB clinical isolates (HN878, EAI, and IO) and purified LAM from these strains to present an integrated analytical approach of one-dimensional and two-dimensional Nuclear Magnetic Resonance (NMR) spectroscopy, as well as enzymatic digestion and site-specific mass spectrometry (MS) to probe LAM structure and behavior at multiple levels. Overall, we found that the glycan was similar in all LAM preparations, albeit with subtle variations. Succinates, lactates, hydroxybutyrate, acetate, and the hallmark of Mtb LAM-methylthioxylose (MTX), adorned the nonreducing terminal arabinan of these LAM species. Newly identified acetoxy/hydroxybutyrate was present only in LAM from EAI and IO Mtb strains. Notably, detailed LC/MS-MS unambiguously showed that all acyl modifications and the lactyl ether in LAM are at the 3-OH position of the 2-linked arabinofuranose adjacent to the terminal β-arabinofuranose. Finally, after sequential enzymatic deglycosylation of LAM, the residual glycan that has ∼50% of α−arabinofuranose -(1→5) linked did not bind to monoclonal antibody CS35. These data clearly indicate the importance of the arabinan termini arrangements for the antigenicity of LAM.
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Affiliation(s)
- Prithwiraj De
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Anita G Amin
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Danara Flores
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Anne Simpson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Karen Dobos
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA.
| | - Delphi Chatterjee
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA.
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11
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Broger T, Nicol MP, Sigal GB, Gotuzzo E, Zimmer AJ, Surtie S, Caceres-Nakiche T, Mantsoki A, Reipold EI, Székely R, Tsionsky M, van Heerden J, Plisova T, Chikamatsu K, Lowary TL, Pinter A, Mitarai S, Moreau E, Schumacher SG, Denkinger CM. Diagnostic accuracy of 3 urine lipoarabinomannan tuberculosis assays in HIV-negative outpatients. J Clin Invest 2020; 130:5756-5764. [PMID: 32692731 PMCID: PMC7598043 DOI: 10.1172/jci140461] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/16/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUNDInadequate tuberculosis (TB) diagnostics are a major hurdle in the reduction of disease burden, and accurate point-of-care tests (POCTs) are urgently needed. We assessed the diagnostic accuracy of Fujifilm SILVAMP TB lipoarabinomannan (FujiLAM) POCT for TB diagnosis in HIV-negative outpatients and compared it with Alere Determine TB LAM Ag (AlereLAM) POCT and a laboratory-based ultrasensitive electrochemiluminescence LAM research assay (EclLAM).METHODSIn this multicenter diagnostic test accuracy study, we recruited HIV-negative adults with symptoms suggestive of pulmonary TB presenting to outpatient health care centers in Peru and South Africa. Urine samples were tested using FujiLAM, AlereLAM, and EclLAM, and the diagnostic accuracy was assessed against a microbiological reference standard (MRS) and a composite reference standard.RESULTSThree hundred seventy-two HIV-negative participants were included and the prevalence of microbiologically confirmed TB was 30%. Compared with the MRS, the sensitivities of AlereLAM, FujiLAM, and EclLAM were 10.8% (95% confidence interval [CI] 6.3%-18.0%), 53.2% (95% CI 43.9%-62.1%), and 66.7% (95% CI 57.5%-74.7%), respectively. The specificities of AlereLAM, FujiLAM, and EclLAM were 92.3% (95% CI 88.5%-95.0%), 98.9% (95% CI 96.7%-99.6%), and 98.1% (95% CI 95.6%-99.2%), respectively. Positive likelihood ratios of AlereLAM, FujiLAM, and EclLAM were 1.4, 46.2, and 34.8, respectively, and positive predictive values were 37.5%, 95.2%, and 93.7%, respectively.CONCLUSIONCompared with AlereLAM, FujiLAM detected 5 times more patients with TB in HIV-negative participants, had a high positive predictive value, and has the potential to improve rapid diagnosis of TB at the point-of-care. EclLAM demonstrated that additional sensitivity gains are possible, which highlights LAM's potential as a biomarker. Additional research is required to assess FujiLAM's performance in prospective cohorts, its cost-effectiveness, and its impact in real-world clinical settings.FUNDINGGlobal Health Innovative Technology Fund, the UK Department for International Development, the Dutch Ministry of Foreign Affairs, the Bill and Melinda Gates Foundation, the Australian Department of Foreign Affairs and Trade, the German Federal Ministry of Education and Research through Kreditanstalt für Wiederaufbau, and the NIH and National Institute of Allergy and Infectious Diseases.
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Affiliation(s)
- Tobias Broger
- FIND, Geneva, Switzerland
- Division of Tropical Medicine, Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Mark P. Nicol
- Division of Infection and Immunity, School of Biomedical Sciences, University of Western Australia, Perth, Australia
- Division of Medical Microbiology, University of Cape Town, Cape Town, South Africa
| | | | | | | | - Shireen Surtie
- Division of Medical Microbiology, University of Cape Town, Cape Town, South Africa
| | | | | | | | | | | | - Judith van Heerden
- Division of Medical Microbiology, University of Cape Town, Cape Town, South Africa
| | | | - Kinuyo Chikamatsu
- Department of Mycobacterium Reference and Research, Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Tokyo, Japan
| | - Todd L. Lowary
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Abraham Pinter
- Public Health Research Institute Center, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
| | - Satoshi Mitarai
- Department of Mycobacterium Reference and Research, Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Tokyo, Japan
| | | | | | - Claudia M. Denkinger
- FIND, Geneva, Switzerland
- Division of Tropical Medicine, Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
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12
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Li Z, Zheng C, Terreni M, Tanzi L, Sollogoub M, Zhang Y. Novel Vaccine Candidates against Tuberculosis. Curr Med Chem 2020; 27:5095-5118. [DOI: 10.2174/0929867326666181126112124] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/08/2018] [Accepted: 11/19/2018] [Indexed: 12/18/2022]
Abstract
Ranking above AIDS, Tuberculosis (TB) is the ninth leading cause of death affecting and
killing many individuals every year. Drugs’ efficacy is limited by a series of problems such as Multi-
Drug Resistance (MDR) and Extensively-Drug Resistance (XDR). Meanwhile, the only licensed vaccine
BCG (Bacillus Calmette-Guérin) existing for over 90 years is not effective enough. Consequently,
it is essential to develop novel vaccines for TB prevention and immunotherapy. This paper
provides an overall review of the TB prevalence, immune system response against TB and recent
progress of TB vaccine research and development. Several vaccines in clinical trials are described as
well as LAM-based candidates.
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Affiliation(s)
- Zhihao Li
- Sorbonne Universite, CNRS, Institut Parisien de Chimie Moleculaire (UMR 8232), 4 Place Jussieu, 75005 Paris, France
| | - Changping Zheng
- Sorbonne Universite, CNRS, Institut Parisien de Chimie Moleculaire (UMR 8232), 4 Place Jussieu, 75005 Paris, France
| | - Marco Terreni
- Drug Sciences Department, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
| | - Lisa Tanzi
- Drug Sciences Department, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
| | - Matthieu Sollogoub
- Sorbonne Universite, CNRS, Institut Parisien de Chimie Moleculaire (UMR 8232), 4 Place Jussieu, 75005 Paris, France
| | - Yongmin Zhang
- Sorbonne Universite, CNRS, Institut Parisien de Chimie Moleculaire (UMR 8232), 4 Place Jussieu, 75005 Paris, France
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13
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A Concise Synthesis of Oligosaccharides Derived From Lipoarabinomannan (LAM) with Glycosyl Donors Having a Nonparticipating Group at C2. European J Org Chem 2020. [DOI: 10.1002/ejoc.201901915] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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14
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Mayfield AB, Metternich JB, Trotta AH, Jacobsen EN. Stereospecific Furanosylations Catalyzed by Bis-thiourea Hydrogen-Bond Donors. J Am Chem Soc 2020; 142:4061-4069. [PMID: 32013410 DOI: 10.1021/jacs.0c00335] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We report a new method for stereoselective O-furanosylation reactions promoted by a precisely tailored bis-thiourea hydrogen-bond-donor catalyst. Furanosyl donors outfitted with an anomeric dialkylphosphate leaving group undergo substitution with high anomeric selectivity, providing access to the challenging 1,2-cis substitution pattern with a range of alcohol acceptors. A variety of stereochemically distinct, benzyl-protected glycosyl donors were engaged successfully as substrates. Mechanistic studies support a stereospecific mechanism in which rate-determining substitution occurs from a catalyst-donor resting-state complex.
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Affiliation(s)
- Andrew B Mayfield
- Department of Chemistry & Chemical Biology , Harvard University , Cambridge , Massachusetts 02138 , United States
| | - Jan B Metternich
- Department of Chemistry & Chemical Biology , Harvard University , Cambridge , Massachusetts 02138 , United States
| | - Adam H Trotta
- Department of Chemistry & Chemical Biology , Harvard University , Cambridge , Massachusetts 02138 , United States
| | - Eric N Jacobsen
- Department of Chemistry & Chemical Biology , Harvard University , Cambridge , Massachusetts 02138 , United States
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15
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Bulterys MA, Wagner B, Redard-Jacot M, Suresh A, Pollock NR, Moreau E, Denkinger CM, Drain PK, Broger T. Point-Of-Care Urine LAM Tests for Tuberculosis Diagnosis: A Status Update. J Clin Med 2019; 9:E111. [PMID: 31906163 PMCID: PMC7020089 DOI: 10.3390/jcm9010111] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 12/24/2019] [Accepted: 12/25/2019] [Indexed: 12/22/2022] Open
Abstract
Most diagnostic tests for tuberculosis (TB) rely on sputum samples, which are difficult to obtain and have low sensitivity in immunocompromised patients, patients with disseminated TB, and children, delaying treatment initiation. The World Health Organization (WHO) calls for the development of a rapid, biomarker-based, non-sputum test capable of detecting all forms of TB at the point-of-care to enable immediate treatment initiation. Lipoarabinomannan (LAM) is the only WHO-endorsed TB biomarker that can be detected in urine, an easily collected sample. This status update discusses the characteristics of LAM as a biomarker, describes the performance of first-generation urine LAM tests and reasons for slow uptake, and presents considerations for developing the next generation of more sensitive and impactful tests. Next-generation urine LAM tests have the potential to reach adult and pediatric patients regardless of HIV status or site of infection and facilitate global TB control. Implementation and scale-up of existing LAM tests and development of next-generation assays should be prioritized.
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Affiliation(s)
- Michelle A. Bulterys
- FIND, 1202 Geneva, Switzerland
- International Clinical Research Center, University of Washington, Seattle, WA 98105, USA
| | | | | | | | - Nira R. Pollock
- Department of Laboratory Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
| | | | - Claudia M. Denkinger
- FIND, 1202 Geneva, Switzerland
- Division of Tropical Medicine, Center of Infectious Diseases, University of Heidelberg, 69120 Heidelberg, Germany
| | - Paul K. Drain
- International Clinical Research Center, University of Washington, Seattle, WA 98105, USA
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16
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Madacki J, Mas Fiol G, Brosch R. Update on the virulence factors of the obligate pathogen Mycobacterium tuberculosis and related tuberculosis-causing mycobacteria. INFECTION GENETICS AND EVOLUTION 2019; 72:67-77. [DOI: 10.1016/j.meegid.2018.12.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/02/2018] [Accepted: 12/07/2018] [Indexed: 12/21/2022]
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17
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Han L, Wang L, Guo Z. An extensive review of studies on mycobacterium cell wall polysaccharide-related oligosaccharides – part II: Synthetic studies on complex arabinofuranosyl oligosaccharides carrying other functional motifs and related derivatives and analogs. J Carbohydr Chem 2019. [DOI: 10.1080/07328303.2019.1630840] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Liwen Han
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji′nan, China
| | - Lizhen Wang
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji′nan, China
| | - Zhongwu Guo
- Department of Chemistry, University of Florida, Gainesville, FL, United States
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18
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A Novel Sensitive Immunoassay Targeting the 5-Methylthio-d-Xylofuranose-Lipoarabinomannan Epitope Meets the WHO's Performance Target for Tuberculosis Diagnosis. J Clin Microbiol 2018; 56:JCM.01338-18. [PMID: 30257899 PMCID: PMC6258851 DOI: 10.1128/jcm.01338-18] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Accepted: 09/19/2018] [Indexed: 12/30/2022] Open
Abstract
The only currently commercialized point-of-care assay for tuberculosis (TB) that measures lipoarabinomannan (LAM) in urine (Alere LF-LAM) has insufficient sensitivity. We evaluated the potential of 100 novel monoclonal antibody pairs targeting a variety of LAM epitopes on a sensitive electrochemiluminescence platform to improve the diagnostic accuracy. The only currently commercialized point-of-care assay for tuberculosis (TB) that measures lipoarabinomannan (LAM) in urine (Alere LF-LAM) has insufficient sensitivity. We evaluated the potential of 100 novel monoclonal antibody pairs targeting a variety of LAM epitopes on a sensitive electrochemiluminescence platform to improve the diagnostic accuracy. In the screening, many antibody pairs showed high reactivity to purified LAM but performed poorly at detecting urinary LAM in clinical samples, suggesting differences in antigen structure and immunoreactivity of the different LAM sources. The 12 best antibody pairs from the screening were tested in a retrospective case-control study with urine samples from 75 adults with presumptive TB. The best antibody pair reached femtomolar analytical sensitivity for LAM detection and an overall clinical sensitivity of 93% (confidence interval [CI], 80% to 97%) and specificity of 97% (CI, 85% to 100%). Importantly, in HIV-negative subjects positive for TB by sputum smear microscopy, the test achieved a sensitivity of 80% (CI, 55% to 93%). This compares to an overall sensitivity of 33% (CI, 20% to 48%) of the Alere LF-LAM and a sensitivity of 13% (CI, 4% to 38%) in HIV-negative subjects in the same sample set. The capture antibody targets a unique 5-methylthio-d-xylofuranose (MTX)-dependent epitope in LAM that is specific to the Mycobacterium tuberculosis complex and shows no cross-reactivity with fast-growing mycobacteria or other bacteria. The present study provides evidence that improved assay methods and reagents lead to increased diagnostic accuracy. The results of this work have informed the development of a sensitive and specific novel LAM point-of-care assay with the aim to meet the WHO's performance target for TB diagnosis.
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19
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Zhang L, Shen K, Taha HA, Lowary TL. Stereocontrolled Synthesis of α-Xylofuranosides Using a Conformationally Restricted Donor. J Org Chem 2018. [PMID: 29895148 DOI: 10.1021/acs.joc.8b00410.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A number of biologically relevant glycoconjugates possess 1,2- cis-furanosidic linkages, a class of glycosidic bond that remains challenging to introduce with high stereoselectivity. In this paper, we report an approach to one family of such linkages, α-xylofuranosides, via the use of thioglycoside donors possessing a conformationally restricting xylylene protecting group. The method was shown to provide the desired targets in good to excellent yield and stereoselectivity. Computational investigations support the proposal that the protecting group locks the electrophilic intermediate in these reactions into a conformation that leads to the high selectivity. The power of the methodology was demonstrated through the synthesis of a complex hexasaccharide motif from lipoarabinomannan, an immunomodulatory polysaccharide from mycobacteria.
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Affiliation(s)
- Li Zhang
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
| | - Ke Shen
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
| | - Hashem A Taha
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
| | - Todd L Lowary
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
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20
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Zhang L, Shen K, Taha HA, Lowary TL. Stereocontrolled Synthesis of α-Xylofuranosides Using a Conformationally Restricted Donor. J Org Chem 2018; 83:7659-7671. [PMID: 29895148 PMCID: PMC6079929 DOI: 10.1021/acs.joc.8b00410] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
![]()
A number of biologically relevant
glycoconjugates possess 1,2-cis-furanosidic linkages,
a class of glycosidic bond that
remains challenging to introduce with high stereoselectivity. In this
paper, we report an approach to one family of such linkages, α-xylofuranosides,
via the use of thioglycoside donors possessing a conformationally
restricting xylylene protecting group. The method was shown to provide
the desired targets in good to excellent yield and stereoselectivity.
Computational investigations support the proposal that the protecting
group locks the electrophilic intermediate in these reactions into
a conformation that leads to the high selectivity. The power of the
methodology was demonstrated through the synthesis of a complex hexasaccharide
motif from lipoarabinomannan, an immunomodulatory polysaccharide from
mycobacteria.
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Affiliation(s)
- Li Zhang
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
| | - Ke Shen
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
| | - Hashem A Taha
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
| | - Todd L Lowary
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
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21
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Choudhary A, Patel D, Honnen W, Lai Z, Prattipati RS, Zheng RB, Hsueh YC, Gennaro ML, Lardizabal A, Restrepo BI, Garcia-Viveros M, Joe M, Bai Y, Shen K, Sahloul K, Spencer JS, Chatterjee D, Broger T, Lowary TL, Pinter A. Characterization of the Antigenic Heterogeneity of Lipoarabinomannan, the Major Surface Glycolipid of Mycobacterium tuberculosis, and Complexity of Antibody Specificities toward This Antigen. THE JOURNAL OF IMMUNOLOGY 2018; 200:3053-3066. [PMID: 29610143 PMCID: PMC5911930 DOI: 10.4049/jimmunol.1701673] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 02/16/2018] [Indexed: 12/17/2022]
Abstract
Lipoarabinomannan (LAM), the major antigenic glycolipid of Mycobacterium tuberculosis, is an important immunodiagnostic target for detecting tuberculosis (TB) infection in HIV-1–coinfected patients, and is believed to mediate a number of functions that promote infection and disease development. To probe the human humoral response against LAM during TB infection, several novel LAM-specific human mAbs were molecularly cloned from memory B cells isolated from infected patients and grown in vitro. The fine epitope specificities of these Abs, along with those of a panel of previously described murine and phage-derived LAM-specific mAbs, were mapped using binding assays against LAM Ags from several mycobacterial species and a panel of synthetic glycans and glycoconjugates that represented diverse carbohydrate structures present in LAM. Multiple reactivity patterns were seen that differed in their specificity for LAM from different species, as well as in their dependence on arabinofuranoside branching and nature of capping at the nonreducing termini. Competition studies with mAbs and soluble glycans further defined these epitope specificities and guided the design of highly sensitive immunodetection assays capable of detecting LAM in urine of TB patients, even in the absence of HIV-1 coinfection. These results highlighted the complexity of the antigenic structure of LAM and the diversity of the natural Ab response against this target. The information and novel reagents described in this study will allow further optimization of diagnostic assays for LAM and may facilitate the development of potential immunotherapeutic approaches to inhibit the functional activities of specific structural motifs in LAM.
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Affiliation(s)
- Alok Choudhary
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - Deendayal Patel
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - William Honnen
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - Zhong Lai
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - Raja Sekhar Prattipati
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - Ruixiang Blake Zheng
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Ying-Chao Hsueh
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - Maria Laura Gennaro
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - Alfred Lardizabal
- Global Tuberculosis Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - Blanca I Restrepo
- University of Texas Health Science Center at Houston, School of Public Health at Brownsville, Brownsville, TX 78520
| | | | - Maju Joe
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Yu Bai
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Ke Shen
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Kamar Sahloul
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - John S Spencer
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523; and
| | - Delphi Chatterjee
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523; and
| | - Tobias Broger
- Foundation for Innovative New Diagnostics, Geneva 1202, Switzerland
| | - Todd L Lowary
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Abraham Pinter
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103;
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22
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Wang L, Feng S, Wang S, Li H, Guo Z, Gu G. Synthesis and Immunological Comparison of Differently Linked Lipoarabinomannan Oligosaccharide–Monophosphoryl Lipid A Conjugates as Antituberculosis Vaccines. J Org Chem 2017; 82:12085-12096. [DOI: 10.1021/acs.joc.7b01817] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Lizhen Wang
- National
Glycoengineering Research Center and Shandong Provincial Key Laboratory
of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan 250100, China
| | - Shaojie Feng
- National
Glycoengineering Research Center and Shandong Provincial Key Laboratory
of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan 250100, China
| | - Subo Wang
- National
Glycoengineering Research Center and Shandong Provincial Key Laboratory
of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan 250100, China
| | - Hui Li
- National
Glycoengineering Research Center and Shandong Provincial Key Laboratory
of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan 250100, China
| | - Zhongwu Guo
- Department
of Chemistry, University of Florida, 214 Leigh Hall, Gainesville, Florida 32611, United States
| | - Guofeng Gu
- National
Glycoengineering Research Center and Shandong Provincial Key Laboratory
of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan 250100, China
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23
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Adero PO, Jarois DR, Crich D. Hydrogenolytic cleavage of naphthylmethyl ethers in the presence of sulfides. Carbohydr Res 2017; 449:11-16. [PMID: 28672165 PMCID: PMC5572532 DOI: 10.1016/j.carres.2017.06.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 06/19/2017] [Accepted: 06/19/2017] [Indexed: 12/11/2022]
Abstract
With the aid of a series of model thioether or thioglycoside containing polyols protected with combinations of benzyl ethers and 2-naphthylmethyl ethers it is demonstrated that the latter are readily cleaved selectively under hydrogenolytic conditions in the presence of the frequently catalyst-poisoning sulfides. These results suggest the possibility of employing 2-naphthylmethyl ethers in place of benzyl ethers in synthetic schemes when hydrogenolytic deprotection is anticipated in the presence of thioether type functionality.
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Affiliation(s)
- Philip O Adero
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, USA
| | - Dean R Jarois
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, USA
| | - David Crich
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, USA.
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24
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Angala SK, McNeil MR, Shi L, Joe M, Pham H, Zuberogoitia S, Nigou J, Boot CM, Lowary TL, Gilleron M, Jackson M. Biosynthesis of the Methylthioxylose Capping Motif of Lipoarabinomannan in Mycobacterium tuberculosis. ACS Chem Biol 2017; 12:682-691. [PMID: 28075556 DOI: 10.1021/acschembio.6b01071] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Lipoarabinomannan (LAM) is a lipoglycan found in abundant quantities in the cell envelope of all mycobacteria. The nonreducing arabinan termini of LAM display species-specific structural microheterogeneity that impacts the biological activity of the entire molecule. Mycobacterium tuberculosis, for instance, produces mannoside caps made of one to three α-(1 → 2)-Manp-linked residues that may be further substituted with an α-(1 → 4)-linked methylthio-d-xylose (MTX) residue. While the biological functions and catalytic steps leading to the formation of the mannoside caps of M. tuberculosis LAM have been well established, the biosynthetic origin and biological relevance of the MTX motif remain elusive. We here report on the discovery of a five-gene cluster dedicated to the biosynthesis of the MTX capping motif of M. tuberculosis LAM, and on the functional characterization of two glycosyltransferases, MtxS and MtxT, responsible, respectively, for the production of decaprenyl-phospho-MTX (DP-MTX) and the transfer of MTX from DP-MTX to the mannoside caps of LAM. Collectively, our NMR spectroscopic and mass spectrometric analyses of mtxS and mtxT overexpressors and knockout mutants support a biosynthetic model wherein the conversion of 5'-methylthioadenosine, which is a ubiquitous byproduct of spermidine biosynthesis, into 5'-methylthioribose-1-phosphate precedes the formation of a 5'-methylthioribose nucleotide sugar, followed by the epimerization at C-3 of the ribose residue, and the transfer of MTX from the nucleotide sugar to decaprenyl-phosphate yielding the substrate for transfer onto LAM. The conservation of the MTX biosynthetic genes in a number of Actinomycetes suggests that this discrete glycosyl substituent may be more widespread in prokaryotes than originally thought.
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Affiliation(s)
- Shiva kumar Angala
- Mycobacteria
Research Laboratories, Department of Microbiology, Immunology and
Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Michael R. McNeil
- Mycobacteria
Research Laboratories, Department of Microbiology, Immunology and
Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Libin Shi
- Mycobacteria
Research Laboratories, Department of Microbiology, Immunology and
Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Maju Joe
- Alberta
Glycomics Centre and Department of Chemistry, The University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Ha Pham
- Mycobacteria
Research Laboratories, Department of Microbiology, Immunology and
Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
| | - Sophie Zuberogoitia
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, F-31077 Toulouse, France
| | - Jérôme Nigou
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, F-31077 Toulouse, France
| | - Claudia M. Boot
- Central
Instrumentation Facility, Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Todd L. Lowary
- Alberta
Glycomics Centre and Department of Chemistry, The University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Martine Gilleron
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, F-31077 Toulouse, France
| | - Mary Jackson
- Mycobacteria
Research Laboratories, Department of Microbiology, Immunology and
Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, United States
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25
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Abstract
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The cell surface (or cell wall) of bacteria is coated with carbohydrate
(or glycan) structures that play a number of important roles. These
include providing structural integrity, serving as a permeability
barrier to extracellular compounds (e.g., drugs) and modulating the
immune system of the host. Of interest to this Account is the cell
wall structure of mycobacteria. There are a host of different mycobacterial
species, some of which cause human disease. The most well-known is Mycobacterium tuberculosis, the causative agent of tuberculosis.
The mycobacterial cell wall is characterized by the presence of unusual
carbohydrate structures that fulfill the roles described above. However,
in many cases, a molecular-level understanding of how mycobacterial
cell wall glycans mediate these processes is lacking. Inspired
by a seminar he heard as a postdoctoral fellow, the author
began his independent research program with a focus on the chemical
synthesis of mycobacterial glycans. The goals were not only to develop
synthetic approaches to these unique structures but also to provide
molecules that could be used to probe their biological function. Initial
work addressed the preparation of fragments of two key polysaccharides,
arabinogalactan and lipoarabinomannan, which contain large numbers
of sugar residues in the furanose (five-membered) ring form. At the
time these investigations began, there were few methods reported for
the synthesis of oligosaccharides containing furanose rings. Thus,
early in the program, a major area of interest was methodology development,
particularly for the preparation of 1,2-cis-furanosides.
To solve this challenge, a range of conformationally restricted donors
have been developed, both in the author’s group and others,
which provide 1,2-cis-furanosidic linkages with high
stereoselectivity. These investigations were followed by application
of the developed
methods to the synthesis of a range of target molecules containing
arabinofuranose and galactofuranose residues. These molecules have
now found application in biochemical, immunological, and structural
biology investigations, which have shed light on their biosynthesis
and how these motifs are recognized by both the innate and adaptive
immune systems. More recently, attention has been directed toward
the synthesis
of another class of immunologically active mycobacterial cell wall
glycans, the extractable glycolipids. In this case, efforts have been
primarily on phenolic glycolipids, and the compounds synthesized have
been used to evaluate their ability to modulate cytokine release.
Over the past 20 years, the use of chemical synthesis to provide increasingly
complex glycan structures has provided significant benefit to the
burgeoning field of mycobacterial glycobiology. Through the efforts
of groups from around the globe, access to these compounds is now
possible via relatively straightforward methods. As the pool of mycobacterial
glycans continues to grow, so too will our understanding of their
role in disease, which will undoubtedly lead to new strategies to
prevent or treat mycobacterial infections.
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Affiliation(s)
- Todd L. Lowary
- Alberta Glycomics Centre
and Department of Chemistry, University of Alberta, Gunning−Lemieux
Chemistry Centre, Edmonton, Alberta T6G 2G2, Canada
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26
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Abstract
The cell surface (or cell wall) of bacteria is coated with carbohydrate (or glycan) structures that play a number of important roles. These include providing structural integrity, serving as a permeability barrier to extracellular compounds (e.g., drugs) and modulating the immune system of the host. Of interest to this Account is the cell wall structure of mycobacteria. There are a host of different mycobacterial species, some of which cause human disease. The most well-known is Mycobacterium tuberculosis, the causative agent of tuberculosis. The mycobacterial cell wall is characterized by the presence of unusual carbohydrate structures that fulfill the roles described above. However, in many cases, a molecular-level understanding of how mycobacterial cell wall glycans mediate these processes is lacking. Inspired by a seminar he heard as a postdoctoral fellow, the author began his independent research program with a focus on the chemical synthesis of mycobacterial glycans. The goals were not only to develop synthetic approaches to these unique structures but also to provide molecules that could be used to probe their biological function. Initial work addressed the preparation of fragments of two key polysaccharides, arabinogalactan and lipoarabinomannan, which contain large numbers of sugar residues in the furanose (five-membered) ring form. At the time these investigations began, there were few methods reported for the synthesis of oligosaccharides containing furanose rings. Thus, early in the program, a major area of interest was methodology development, particularly for the preparation of 1,2-cis-furanosides. To solve this challenge, a range of conformationally restricted donors have been developed, both in the author's group and others, which provide 1,2-cis-furanosidic linkages with high stereoselectivity. These investigations were followed by application of the developed methods to the synthesis of a range of target molecules containing arabinofuranose and galactofuranose residues. These molecules have now found application in biochemical, immunological, and structural biology investigations, which have shed light on their biosynthesis and how these motifs are recognized by both the innate and adaptive immune systems. More recently, attention has been directed toward the synthesis of another class of immunologically active mycobacterial cell wall glycans, the extractable glycolipids. In this case, efforts have been primarily on phenolic glycolipids, and the compounds synthesized have been used to evaluate their ability to modulate cytokine release. Over the past 20 years, the use of chemical synthesis to provide increasingly complex glycan structures has provided significant benefit to the burgeoning field of mycobacterial glycobiology. Through the efforts of groups from around the globe, access to these compounds is now possible via relatively straightforward methods. As the pool of mycobacterial glycans continues to grow, so too will our understanding of their role in disease, which will undoubtedly lead to new strategies to prevent or treat mycobacterial infections.
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Affiliation(s)
- Todd L Lowary
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta , Gunning-Lemieux Chemistry Centre, Edmonton, Alberta T6G 2G2, Canada
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27
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Gupta-Wright A, Peters JA, Flach C, Lawn SD. Detection of lipoarabinomannan (LAM) in urine is an independent predictor of mortality risk in patients receiving treatment for HIV-associated tuberculosis in sub-Saharan Africa: a systematic review and meta-analysis. BMC Med 2016; 14:53. [PMID: 27007773 PMCID: PMC4804532 DOI: 10.1186/s12916-016-0603-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/17/2016] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Simple immune capture assays that detect mycobacterial lipoarabinomannan (LAM) antigen in urine are promising new tools for the diagnosis of HIV-associated tuberculosis (HIV-TB). In addition, however, recent prospective cohort studies of patients with HIV-TB have demonstrated associations between LAM in the urine and increased mortality risk during TB treatment, indicating an additional utility of urinary LAM as a prognostic marker. We conducted a systematic review and meta-analysis to summarise the evidence concerning the strength of this relationship in adults with HIV-TB in sub-Saharan Africa, thereby quantifying the assay's prognostic value. METHODS We searched MEDLINE and Embase databases using comprehensive search terms for 'HIV', 'TB', 'LAM' and 'sub-Saharan Africa'. Identified studies were reviewed and selected according to predefined criteria. RESULTS We identified 10 studies eligible for inclusion in this systematic review, reporting on a total of 1172 HIV-TB cases. Of these, 512 patients (44 %) tested positive for urinary LAM. After a variable duration of follow-up of between 2 and 6 months, overall case fatality rates among HIV-TB cases varied between 7 % and 53 %. Pooled summary estimates generated by random-effects meta-analysis showed a two-fold increased risk of mortality for urinary LAM-positive HIV-TB cases compared to urinary LAM-negative HIV-TB cases (relative risk 2.3, 95 % confidence interval 1.6-3.1). Some heterogeneity was explained by study setting and patient population in sub-group analyses. Five studies also reported multivariable analyses of risk factors for mortality, and pooled summary estimates demonstrated over two-fold increased mortality risk (odds ratio 2.5, 95 % confidence interval 1.4-4.5) among urinary LAM-positive HIV-TB cases, even after adjustment for other risk factors for mortality, including CD4 cell count. CONCLUSIONS We have demonstrated that detectable LAM in urine is associated with increased risk of mortality during TB treatment, and that this relationship remains after adjusting for other risk factors for mortality. This may simply be due to a positive test for urinary LAM serving as a marker of higher mycobacterial load and greater disease dissemination and severity. Alternatively, LAM antigen may directly compromise host immune responses through its known immunomodulatory effects. Detectable LAM in the urine is an independent risk factor for mortality among patients receiving treatment for HIV-TB. Further research is warranted to elucidate the underlying mechanisms and to determine whether this vulnerable patient population may benefit from adjunctive interventions.
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Affiliation(s)
- Ankur Gupta-Wright
- Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
- Malawi-Liverpool-Wellcome Trust Clinical Research Program, College of Medicine, University of Malawi, Blantyre, Malawi.
| | - Jurgens A Peters
- Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Clare Flach
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | - Stephen D Lawn
- Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
- The Desmond Tutu HIV Centre, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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28
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Taha HA, Castillo N, Roy PN, Lowary TL. Conformational Studies of Methyl β-d-Arabinofuranoside Using the AMBER/GLYCAM Approach. J Chem Theory Comput 2015; 5:430-8. [PMID: 26610115 DOI: 10.1021/ct800384h] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Furanosides are important constituents of a number of glycoconjugates from many microorganisms. The highly flexible nature of these furanosyl moieties is believed to contribute significantly to their role in biological processes. Therefore, an understanding of the conformational preferences of these molecules is an important area of research. As part of a larger program involved in the conformational analysis of mycobacterial oligofuranosides, molecular dynamics simulations on methyl β-d-arabinofuranoside (3) have been carried out using the AMBER forcefield and the GLYCAM carbohydrate parameter set. This approach was used to predict the rotamer population distribution about the hydroxymethyl group (C4-C5 bond) as well as the ring puckering of this flexible ring system. Comparison of the conformer distributions obtained during the simulation of 3 using the TIP3P water model with those obtained by analysis of (1)H-(1)H coupling constant data indicated that this water model was insufficient to describe the solvation of this system. However, the use of the TIP4P and TIP5P models led to improved agreement with conformer populations obtained from NMR data.
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Affiliation(s)
- Hashem A Taha
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, Gunning-Lemieux Chemistry Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2G2, and Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Norberto Castillo
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, Gunning-Lemieux Chemistry Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2G2, and Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Pierre-Nicholas Roy
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, Gunning-Lemieux Chemistry Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2G2, and Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Todd L Lowary
- Department of Chemistry and Alberta Ingenuity Centre for Carbohydrate Science, Gunning-Lemieux Chemistry Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2G2, and Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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29
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Sahloul K, Lowary TL. Development of an Orthogonal Protection Strategy for the Synthesis of Mycobacterial Arabinomannan Fragments. J Org Chem 2015; 80:11417-34. [DOI: 10.1021/acs.joc.5b02083] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Kamar Sahloul
- Alberta
Glycomics Centre
and Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - Todd L. Lowary
- Alberta
Glycomics Centre
and Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
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30
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Affiliation(s)
- Monika Jankute
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom;
| | - Jonathan A.G. Cox
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom;
| | - James Harrison
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom;
| | - Gurdyal S. Besra
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom;
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31
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Wang L, Feng S, An L, Gu G, Guo Z. Synthetic and Immunological Studies of Mycobacterial Lipoarabinomannan Oligosaccharides and Their Protein Conjugates. J Org Chem 2015; 80:10060-75. [DOI: 10.1021/acs.joc.5b01686] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lizhen Wang
- National Glycoengineering
Research Center, School of Life Science, Shandong University, Jinan 250100, China
| | - Shaojie Feng
- National Glycoengineering
Research Center, School of Life Science, Shandong University, Jinan 250100, China
| | - Lian An
- National Glycoengineering
Research Center, School of Life Science, Shandong University, Jinan 250100, China
| | - Guofeng Gu
- National Glycoengineering
Research Center, School of Life Science, Shandong University, Jinan 250100, China
| | - Zhongwu Guo
- National Glycoengineering
Research Center, School of Life Science, Shandong University, Jinan 250100, China
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32
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Mandal PK, Chheda PR. Synthesis and biotinylation of oligosaccharide fragments of mannosylated and 5-deoxy-5-methylthio-xylofuranosylated lipoarabinomannan from Mycobacterium tuberculosis. Carbohydr Res 2015; 407:104-10. [DOI: 10.1016/j.carres.2015.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 01/06/2015] [Accepted: 01/11/2015] [Indexed: 10/24/2022]
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33
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Kaur D, Angala SK, Wu SW, Khoo KH, Chatterjee D, Brennan PJ, Jackson M, McNeil MR. A single arabinan chain is attached to the phosphatidylinositol mannosyl core of the major immunomodulatory mycobacterial cell envelope glycoconjugate, lipoarabinomannan. J Biol Chem 2014; 289:30249-30256. [PMID: 25231986 DOI: 10.1074/jbc.m114.599415] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lipoarabinomannan (LAM) is composed of a phosphatidylinositol anchor followed by a mannan followed by an arabinan that may be capped with various motifs including oligosaccharides of mannose. A related polymer, lipomannan (LM), is composed of only the phosphatidylinositol and mannan core. Both the structure and the biosynthesis of LAM have been studied extensively. However, fundamental questions about the branching structure of LM and the number of arabinan chains on the mannan backbone in LAM remain. LM and LAM molecules produced by three different glycosyltransferase mutants of Mycobacterium smegmatis were used here to investigate these questions. Using an MSMEG_4241 mutant that lacks the α-(1,6)-mannosyltransferase used late in LM elongation, we showed that the reducing end region of the mannan that is attached to inositol has 5-7 unbranched α-6-linked-mannosyl residues followed by two or three α-6-linked mannosyl residues branched with single α-mannopyranose residues at O-2. After these branched mannosyl residues, the α-6-linked mannan chain is terminated with an α-mannopyranose at O-2 rather than O-6 of the penultimate residue. Analysis of the number of arabinans attached to the mannan core of LM in two other mutants (ΔembC and ΔMSMEG_4247) demonstrated exactly one arabinosyl substitution of the mannan core suggestive of the arabinosylation of a linear LM precursor with ∼10-12 mannosyl residues followed by additional mannosylation of the core and arabinosylation of a single arabinosyl "primer." Thus, these studies suggest that only a single arabinan chain attached near the middle of the mannan core is present in mature LAM and allow for an updated working model of the biosynthetic pathway of LAM and LM.
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Affiliation(s)
- Devinder Kaur
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523 and
| | - Shiva K Angala
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523 and
| | - Sz-Wei Wu
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Kay-Hooi Khoo
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Delphi Chatterjee
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523 and
| | - Patrick J Brennan
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523 and
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523 and.
| | - Michael R McNeil
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523 and.
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34
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Angala SK, Belardinelli JM, Huc-Claustre E, Wheat WH, Jackson M. The cell envelope glycoconjugates of Mycobacterium tuberculosis. Crit Rev Biochem Mol Biol 2014; 49:361-99. [PMID: 24915502 PMCID: PMC4436706 DOI: 10.3109/10409238.2014.925420] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Tuberculosis (TB) remains the second most common cause of death due to a single infectious agent. The cell envelope of Mycobacterium tuberculosis (Mtb), the causative agent of the disease in humans, is a source of unique glycoconjugates and the most distinctive feature of the biology of this organism. It is the basis of much of Mtb pathogenesis and one of the major causes of its intrinsic resistance to chemotherapeutic agents. At the same time, the unique structures of Mtb cell envelope glycoconjugates, their antigenicity and essentiality for mycobacterial growth provide opportunities for drug, vaccine, diagnostic and biomarker development, as clearly illustrated by recent advances in all of these translational aspects. This review focuses on our current understanding of the structure and biogenesis of Mtb glycoconjugates with particular emphasis on one of the most intriguing and least understood aspect of the physiology of mycobacteria: the translocation of these complex macromolecules across the different layers of the cell envelope. It further reviews the rather impressive progress made in the last 10 years in the discovery and development of novel inhibitors targeting their biogenesis.
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Affiliation(s)
- Shiva Kumar Angala
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University , Fort Collins, CO , USA
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35
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van Rijssel ER, van Delft P, Lodder G, Overkleeft HS, van der Marel GA, Filippov DV, Codée JDC. Furanosyl Oxocarbenium Ion Stability and Stereoselectivity. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201405477] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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36
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van Rijssel ER, van Delft P, Lodder G, Overkleeft HS, van der Marel GA, Filippov DV, Codée JDC. Furanosyl Oxocarbenium Ion Stability and Stereoselectivity. Angew Chem Int Ed Engl 2014; 53:10381-5. [DOI: 10.1002/anie.201405477] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 06/13/2014] [Indexed: 11/09/2022]
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37
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Elsaidi HRH, Barreda DR, Cairo CW, Lowary TL. Mycobacterial phenolic glycolipids with a simplified lipid aglycone modulate cytokine levels through Toll-like receptor 2. Chembiochem 2013; 14:2153-9. [PMID: 24115598 DOI: 10.1002/cbic.201300505] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Indexed: 01/20/2023]
Abstract
Phenolic glycolipids (PGLs) are virulence factors present in the cell walls of many pathogenic mycobacteria. PGLs have been implicated in various aspects of mycobacterial disease, but there are limited structure-activity data available for these molecules. We report here the preparation of seven synthetic PGL analogues, differing from the native compounds in the replacement of the complex phenolic lipid moiety with a p-methoxyphenyl group. The ability of these compounds to stimulate or inhibit the production of cytokines (TNF-α, IL-1β, IL-6, MCP-1) and nitric oxide (NO) was then evaluated by ELISA-based assays. None of the compounds stimulated the production of these biological signalling molecules. In contrast, they each displayed concentration-dependent inhibitory activity, related to the methylation pattern of the molecule and mediated by Toll-like receptor 2. Additional studies revealed that native PGL-I from Mycobacterium leprae and a synthetic PGL-I analogue containing a simplified lipid domain had enhanced inhibitory activities relative to the corresponding analogues containing the p-methoxyphenyl aglycone; however, the natural lipid phenolthiocerol was only weakly active. These studies reveal that synthetic molecules of this type can be used as probes for PGL function. Moreover, their ease of synthesis relative to the natural glycolipids, as well as their more favourable aqueous solubility, should allow for more thorough structure-activity relationship studies.
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Affiliation(s)
- Hassan R H Elsaidi
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Gunning-Lemieux Chemistry Centre, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2 (Canada)
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38
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Taha HA, Richards MR, Lowary TL. Conformational Analysis of Furanoside-Containing Mono- and Oligosaccharides. Chem Rev 2012; 113:1851-76. [DOI: 10.1021/cr300249c] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Hashem A. Taha
- Alberta Glycomics Centre and Department of Chemistry, Gunning−Lemieux Chemistry Centre, University of Alberta, Edmonton, AB, Canada T6G 2G2
| | - Michele R. Richards
- Alberta Glycomics Centre and Department of Chemistry, Gunning−Lemieux Chemistry Centre, University of Alberta, Edmonton, AB, Canada T6G 2G2
| | - Todd L. Lowary
- Alberta Glycomics Centre and Department of Chemistry, Gunning−Lemieux Chemistry Centre, University of Alberta, Edmonton, AB, Canada T6G 2G2
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39
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Turnbull WB, Stalford SA. Methylthioxylose--a jewel in the mycobacterial crown? Org Biomol Chem 2012; 10:5698-706. [PMID: 22575989 DOI: 10.1039/c2ob25630d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Ten years ago an unusual sugar was discovered in a cell wall polysaccharide of Mycobacterium tuberculosis. Structural elucidation revealed the presence of the first thiosugar in a bacterial polysaccharide. Synthetic studies have helped to define its relative and absolute configuration as α-D-methylthioxylofuranosyl. While its biosynthetic origins remain the subject of speculation, work has begun to define its possible biological roles.
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Affiliation(s)
- W Bruce Turnbull
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK.
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40
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Mishra AK, Driessen NN, Appelmelk BJ, Besra GS. Lipoarabinomannan and related glycoconjugates: structure, biogenesis and role in Mycobacterium tuberculosis physiology and host-pathogen interaction. FEMS Microbiol Rev 2011; 35:1126-57. [PMID: 21521247 PMCID: PMC3229680 DOI: 10.1111/j.1574-6976.2011.00276.x] [Citation(s) in RCA: 207] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Approximately one third of the world's population is infected with Mycobacterium tuberculosis, the causative agent of tuberculosis. This bacterium has an unusual lipid-rich cell wall containing a vast repertoire of antigens, providing a hydrophobic impermeable barrier against chemical drugs, thus representing an attractive target for vaccine and drug development. Apart from the mycolyl–arabinogalactan–peptidoglycan complex, mycobacteria possess several immunomodulatory constituents, notably lipomannan and lipoarabinomannan. The availability of whole-genome sequences of M. tuberculosis and related bacilli over the past decade has led to the identification and functional characterization of various enzymes and the potential drug targets involved in the biosynthesis of these glycoconjugates. Both lipomannan and lipoarabinomannan possess highly variable chemical structures, which interact with different receptors of the immune system during host–pathogen interactions, such as Toll-like receptors-2 and C-type lectins. Recently, the availability of mutants defective in the synthesis of these glycoconjugates in mycobacteria and the closely related bacterium, Corynebacterium glutamicum, has paved the way for host–pathogen interaction studies, as well as, providing attenuated strains of mycobacteria for the development of new vaccine candidates. This review provides a comprehensive account of the structure, biosynthesis and immunomodulatory properties of these important glycoconjugates.
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Affiliation(s)
- Arun K Mishra
- School of Biosciences, University of Birmingham, Edgbaston, UK
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41
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Banerjee R, Vats P, Dahale S, Kasibhatla SM, Joshi R. Comparative genomics of cell envelope components in mycobacteria. PLoS One 2011; 6:e19280. [PMID: 21573108 PMCID: PMC3089613 DOI: 10.1371/journal.pone.0019280] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Accepted: 03/25/2011] [Indexed: 12/26/2022] Open
Abstract
Mycobacterial cell envelope components have been a major focus of research due to their unique features that confer intrinsic resistance to antibiotics and chemicals apart from serving as a low-permeability barrier. The complex lipids secreted by Mycobacteria are known to evoke/repress host-immune response and thus contribute to its pathogenicity. This study focuses on the comparative genomics of the biosynthetic machinery of cell wall components across 21-mycobacterial genomes available in GenBank release 179.0. An insight into survival in varied environments could be attributed to its variation in the biosynthetic machinery. Gene-specific motifs like 'DLLAQPTPAW' of ufaA1 gene, novel functional linkages such as involvement of Rv0227c in mycolate biosynthesis; Rv2613c in LAM biosynthesis and Rv1209 in arabinogalactan peptidoglycan biosynthesis were detected in this study. These predictions correlate well with the available mutant and coexpression data from TBDB. It also helped to arrive at a minimal functional gene set for these biosynthetic pathways that complements findings using TraSH.
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Affiliation(s)
- Ruma Banerjee
- Bioinformatics Group, Centre for Development of Advanced Computing, Pune University Campus, Pune, Maharashtra, India
| | - Pankaj Vats
- Bioinformatics Group, Centre for Development of Advanced Computing, Pune University Campus, Pune, Maharashtra, India
| | - Sonal Dahale
- Bioinformatics Group, Centre for Development of Advanced Computing, Pune University Campus, Pune, Maharashtra, India
| | - Sunitha Manjari Kasibhatla
- Bioinformatics Group, Centre for Development of Advanced Computing, Pune University Campus, Pune, Maharashtra, India
| | - Rajendra Joshi
- Bioinformatics Group, Centre for Development of Advanced Computing, Pune University Campus, Pune, Maharashtra, India
- * E-mail:
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Chlubnová I, Sylla B, Nugier-Chauvin C, Daniellou R, Legentil L, Kralová B, Ferrières V. Natural glycans and glycoconjugates as immunomodulating agents. Nat Prod Rep 2011; 28:937-52. [DOI: 10.1039/c1np00005e] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Tam PH, Lowary TL. Mycobacterial lipoarabinomannan fragments as haptens for potential anti-tuberculosis vaccines. CARBOHYDRATE CHEMISTRY 2010. [DOI: 10.1039/9781849730891-00038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Pui-Hang Tam
- Alberta Ingenuity Centre for Carbohydrate Science and Department of Chemistry, The University of Alberta Gunning-Lemieux Chemistry Centre Edmonton AB, T6G 2G2 Canada
| | - Todd L. Lowary
- Alberta Ingenuity Centre for Carbohydrate Science and Department of Chemistry, The University of Alberta Gunning-Lemieux Chemistry Centre Edmonton AB, T6G 2G2 Canada
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Umesiri FE, Sanki AK, Boucau J, Ronning DR, Sucheck SJ. Recent advances toward the inhibition of mAG and LAM synthesis in Mycobacterium tuberculosis. Med Res Rev 2010; 30:290-326. [DOI: 10.1002/med.20190] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Cao B, Williams SJ. Chemical approaches for the study of the mycobacterial glycolipids phosphatidylinositol mannosides, lipomannan and lipoarabinomannan. Nat Prod Rep 2010; 27:919-47. [DOI: 10.1039/c000604a] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Chlubnová I, Filipp D, Spiwok V, Dvořáková H, Daniellou R, Nugier-Chauvin C, Králová B, Ferrières V. Enzymatic synthesis of oligo-d-galactofuranosides and l-arabinofuranosides: from molecular dynamics to immunological assays. Org Biomol Chem 2010; 8:2092-102. [DOI: 10.1039/b926988f] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kaur D, Guerin ME, Skovierová H, Brennan PJ, Jackson M. Chapter 2: Biogenesis of the cell wall and other glycoconjugates of Mycobacterium tuberculosis. ADVANCES IN APPLIED MICROBIOLOGY 2009; 69:23-78. [PMID: 19729090 DOI: 10.1016/s0065-2164(09)69002-x] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The re-emergence of tuberculosis in its present-day manifestations - single, multiple and extensive drug-resistant forms and as HIV-TB coinfections - has resulted in renewed research on fundamental questions such as the nature of the organism itself, Mycobacterium tuberculosis, the molecular basis of its pathogenesis, definition of the immunological response in animal models and humans, and development of new intervention strategies such as vaccines and drugs. Foremost among these developments has been the precise chemical definition of the complex and distinctive cell wall of M. tuberculosis, elucidation of the relevant pathways and underlying genetics responsible for the synthesis of the hallmark moieties of the tubercle bacillus such as the mycolic acid-arabinogalactan-peptidoglycan complex, the phthiocerol- and trehalose-containing effector lipids, the phosphatidylinositol-containing mannosides, lipomannosides and lipoarabinomannosides, major immunomodulators, and others. In this review, the laboratory personnel who have been the focal point of some to these developments review recent progress towards a comprehensive understanding of the basic physiology and functions of the cell wall of M. tuberculosis.
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Affiliation(s)
- Devinder Kaur
- Department of Microbiology, Immunology and Pathology, Mycobacteria Research Laboratories, Colorado State University, Fort Collins, CO 80523-1682, USA
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Tam PH, Lowary TL. Epimeric and amino disaccharide analogs as probes of an alpha-(1-->6)-mannosyltransferase involved in mycobacterial lipoarabinomannan biosynthesis. Org Biomol Chem 2009; 8:181-92. [PMID: 20024149 DOI: 10.1039/b916580k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mycobacterial lipoarabinomannan (LAM) is an important, immunologically active glycan found in the cell wall of mycobacteria, including the human pathogen Mycobacterium tuberculosis. At the core of LAM is a mannan domain comprised of alpha-(1-->6)-linked-mannopyranose (Manp) residues. Previously, we and others have demonstrated that alpha-Manp-(1-->6)-alpha-Manp disaccharides (e.g., Manp-(1-->6)-alpha-ManpOctyl, ) are the minimum acceptor substrates for enzymes involved in the assembly of the LAM mannan core. We report here the synthesis five epimeric and three amino analogs of , and their subsequent biochemical evaluation against an alpha-(1-->6)-ManT activity present in a membrane preparation from M. smegmatis. Changing the manno- configuration of either residue of to talo- or gluco- led to a reduction or loss of activity, thus confirming earlier work showing that the C-2 and C-4 hydroxyl groups of each monosaccharide were important for enzymatic recognition. Characterization of the products formed from these analogs was done using a combination of mass spectrometry and glycosidase digestion, and full substrate kinetics were also performed. The analogs in which the acceptor hydroxyl group had been replaced with an amino group were, as expected, not substrates for the enzyme, but were weak inhibitors.
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Affiliation(s)
- Pui Hang Tam
- Alberta Ingenuity Centre for Carbohydrate Science and Department of Chemistry, The University of Alberta, Gunning-Lemieux Chemistry Centre, Edmonton, AB T6G 2G2, Canada
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Murase T, Zheng RB, Joe M, Bai Y, Marcus SL, Lowary TL, Ng KK. Structural Insights into Antibody Recognition of Mycobacterial Polysaccharides. J Mol Biol 2009; 392:381-92. [DOI: 10.1016/j.jmb.2009.06.074] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 06/26/2009] [Accepted: 06/29/2009] [Indexed: 10/20/2022]
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