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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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Kelly SD, Duong NH, Nothof JT, Lowary TL, Whitfield C. Three-component systems represent a common pathway for extracytoplasmic addition of pentofuranose sugars into bacterial glycans. Proc Natl Acad Sci U S A 2024; 121:e2402554121. [PMID: 38748580 PMCID: PMC11127046 DOI: 10.1073/pnas.2402554121] [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: 02/05/2024] [Accepted: 04/18/2024] [Indexed: 05/27/2024] Open
Abstract
Cell surface glycans are major drivers of antigenic diversity in bacteria. The biochemistry and molecular biology underpinning their synthesis are important in understanding host-pathogen interactions and for vaccine development with emerging chemoenzymatic and glycoengineering approaches. Structural diversity in glycostructures arises from the action of glycosyltransferases (GTs) that use an immense catalog of activated sugar donors to build the repeating unit and modifying enzymes that add further heterogeneity. Classical Leloir GTs incorporate α- or β-linked sugars by inverting or retaining mechanisms, depending on the nucleotide sugar donor. In contrast, the mechanism of known ribofuranosyltransferases is confined to β-linkages, so the existence of α-linked ribofuranose in some glycans dictates an alternative strategy. Here, we use Citrobacter youngae O1 and O2 lipopolysaccharide O antigens as prototypes to describe a widespread, versatile pathway for incorporating side-chain α-linked pentofuranoses by extracytoplasmic postpolymerization glycosylation. The pathway requires a polyprenyl phosphoribose synthase to generate a lipid-linked donor, a MATE-family flippase to transport the donor to the periplasm, and a GT-C type GT (founding the GT136 family) that performs the final glycosylation reaction. The characterized system shares similarities, but also fundamental differences, with both cell wall arabinan biosynthesis in mycobacteria, and periplasmic glucosylation of O antigens first discovered in Salmonella and Shigella. The participation of auxiliary epimerases allows the diversification of incorporated pentofuranoses. The results offer insight into a broad concept in microbial glycobiology and provide prototype systems and bioinformatic guides that facilitate discovery of further examples from diverse species, some in currently unknown glycans.
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Affiliation(s)
- Steven D. Kelly
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ONN1G 2W1, Canada
| | - Nam Ha Duong
- Institute of Biological Chemistry, Academia Sinica, Nangang, Taipei11529, Taiwan
- Chemical Biology and Molecular Biophysics, Taiwan International Graduate Program, Academia Sinica, Nangang, Taipei11529, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu300044, Taiwan
| | - Jeremy T. Nothof
- Department of Chemistry, University of Alberta, Edmonton, ABT6G 2G2, Canada
| | - Todd L. Lowary
- Institute of Biological Chemistry, Academia Sinica, Nangang, Taipei11529, Taiwan
- Department of Chemistry, University of Alberta, Edmonton, ABT6G 2G2, Canada
- Institute of Biochemical Sciences, National Taiwan University, Taipei10617, Taiwan
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ONN1G 2W1, Canada
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3
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Sparks IL, Nijjer J, Yan J, Morita YS. Lipoarabinomannan regulates septation in Mycobacterium smegmatis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.26.534150. [PMID: 36993273 PMCID: PMC10055410 DOI: 10.1101/2023.03.26.534150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The growth and division of mycobacteria, which include several clinically relevant pathogens, deviate significantly from that of canonical bacterial models. Despite their Gram-positive ancestry, mycobacteria synthesize and elongate a diderm envelope asymmetrically from the poles, with the old pole elongating more robustly than the new pole. In addition to being structurally distinct, the molecular components of the mycobacterial envelope are also evolutionarily unique, including the phosphatidylinositol-anchored lipoglycans lipomannan (LM) and lipoarabinomannan (LAM). LM and LAM modulate host immunity during infection, but their role outside of intracellular survival remains poorly understood, despite their widespread conservation among non-pathogenic and opportunistically pathogenic mycobacteria. Previously, Mycobacterium smegmatis and Mycobacterium tuberculosis mutants producing structurally altered LM and LAM were shown to grow slowly under certain conditions and to be more sensitive to antibiotics, suggesting that mycobacterial lipoglycans may support cellular integrity or growth. To test this, we constructed multiple biosynthetic lipoglycan mutants of M. smegmatis and determined the effect of each mutation on cell wall biosynthesis, envelope integrity, and division. We found that mutants deficient in LAM, but not LM, fail to maintain cell wall integrity in a medium-dependent manner, with envelope deformations specifically associated with septa and new poles. Conversely, a mutant producing abnormally large LAM formed multiseptated cells in way distinct from that observed in a septal hydrolase mutant. These results show that LAM plays critical and distinct roles at subcellular locations associated with division in mycobacteria, including maintenance of local cell envelope integrity and septal placement.
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Affiliation(s)
- Ian L. Sparks
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
| | - Japinder Nijjer
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven CT, USA
- Quantitative Biology Institute, Yale University, New Haven, CT, USA
| | - Jing Yan
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven CT, USA
- Quantitative Biology Institute, Yale University, New Haven, CT, USA
| | - Yasu S. Morita
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
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4
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Rohokale R, Guo Z. Development in the Concept of Bacterial Polysaccharide Repeating Unit-Based Antibacterial Conjugate Vaccines. ACS Infect Dis 2023; 9:178-212. [PMID: 36706246 PMCID: PMC9930202 DOI: 10.1021/acsinfecdis.2c00559] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The surface of cells is coated with a dense layer of glycans, known as the cell glycocalyx. The complex glycans in the glycocalyx are involved in various biological events, such as bacterial pathogenesis, protection of bacteria from environmental stresses, etc. Polysaccharides on the bacterial cell surface are highly conserved and accessible molecules, and thus they are excellent immunological targets. Consequently, bacterial polysaccharides and their repeating units have been extensively studied as antigens for the development of antibacterial vaccines. This Review surveys the recent developments in the synthetic and immunological investigations of bacterial polysaccharide repeating unit-based conjugate vaccines against several human pathogenic bacteria. The major challenges associated with the development of functional carbohydrate-based antibacterial conjugate vaccines are also considered.
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Hadi SA, Brenner EP, Palmer MV, Waters WR, Thacker TC, Vilchèze C, Larsen MH, Jacobs WR, Sreevatsan S. Mycobacterium bovis Strain Ravenel Is Attenuated in Cattle. Pathogens 2022; 11:1330. [PMID: 36422582 PMCID: PMC9699013 DOI: 10.3390/pathogens11111330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/19/2022] [Accepted: 11/08/2022] [Indexed: 08/02/2023] Open
Abstract
Mycobacterium tuberculosis variant bovis (MBO) has one of the widest known mammalian host ranges, including humans. Despite the characterization of this pathogen in the 1800s and whole genome sequencing of a UK strain (AF2122) nearly two decades ago, the basis of its host specificity and pathogenicity remains poorly understood. Recent experimental calf infection studies show that MBO strain Ravenel (MBO Ravenel) is attenuated in the cattle host compared to other pathogenic strains of MBO. In the present study, experimental infections were performed to define attenuation. Whole genome sequencing was completed to identify regions of differences (RD) and single nucleotide polymorphisms (SNPs) to explain the observed attenuation. Comparative genomic analysis of MBO Ravenel against three pathogenic strains of MBO (strains AF2122-97, 10-7428, and 95-1315) was performed. Experimental infection studies on five calves each, with either MBO Ravenel or 95-1315, revealed no visible lesions in all five animals in the Ravenel group despite robust IFN-γ responses. Out of 486 polymorphisms in the present analysis, 173 were unique to MBO Ravenel among the strains compared. A high-confidence subset of nine unique SNPs were missense mutations in genes with annotated functions impacting two major MBO survival and virulence pathways: (1) Cell wall synthesis & transport [espH (A103T), mmpL8 (V888I), aftB (H484Y), eccC5 (T507M), rpfB (E263G)], and (2) Lipid metabolism & respiration [mycP1(T125I), pks5 (G455S), fadD29 (N231S), fadE29 (V360G)]. These substitutions likely contribute to the observed attenuation. Results from experimental calf infections and the functional attributions of polymorphic loci on the genome of MBO Ravenel provide new insights into the strain's genotype-disease phenotype associations.
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Affiliation(s)
- Syeda A. Hadi
- Pathobiology and Diagnostic Investigation Department, Michigan State University, East Lansing, MI 48824, USA
| | - Evan P. Brenner
- Pathobiology and Diagnostic Investigation Department, Michigan State University, East Lansing, MI 48824, USA
| | - Mitchell V. Palmer
- National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA
| | - W. Ray Waters
- National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA
| | - Tyler C. Thacker
- National Veterinary Services Laboratories, US Department of Agriculture, Ames, IA 50010, USA
| | - Catherine Vilchèze
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10475, USA
| | - Michelle H. Larsen
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10475, USA
| | - William R. Jacobs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10475, USA
| | - Srinand Sreevatsan
- Pathobiology and Diagnostic Investigation Department, Michigan State University, East Lansing, MI 48824, USA
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6
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Enhanced immunogenicity of Mycobacterium bovis BCG through CRISPRi mediated depletion of AftC. Cell Surf 2022; 8:100088. [PMID: 36405350 PMCID: PMC9651938 DOI: 10.1016/j.tcsw.2022.100088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/08/2022] [Accepted: 11/08/2022] [Indexed: 11/13/2022] Open
Abstract
Mycobacterium tuberculosis causes the disease tuberculosis and affects a third of the world’s population. The recent COVID-19 pandemic exacerbated the situation with a projected 27% increase in tuberculosis related deaths. M. tuberculosis has an elaborate cell wall consisting of peptidoglycan, arabinogalactan and mycolic acids which shield the bacilli from the toxic bactericidal milieu within phagocytes. Amongst, the numerous glycosyltransferase enzymes involved in mycobacterial cell wall biosynthesis, arabinofuranosyltransferase C (aftC) is responsible for the branching of the arabinan domain in both arabinogalactan and lipoarabinomannan. Using Clustered Regularly Interspaced Short Palindromic Repeats interference (CRISPRi) we have generated aftC knockdowns in Mycobacterium bovis BCG and demonstrated the generation of a truncated, immunogenic lipoarabinomannan within its cell envelope. The aftC depleted BCG mutants were unable to form characteristic mycobacterial pellicular biofilms and elicit a potent immunostimulatory phenotype compared to wild type M. bovis BCG in a THP1 cell line. This study paves the way to further explore novel BCG mutants as promising vaccine boosters in preventing pulmonary tuberculosis.
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Chemical-genetic interaction mapping links carbon metabolism and cell wall structure to tuberculosis drug efficacy. Proc Natl Acad Sci U S A 2022; 119:e2201632119. [PMID: 35380903 PMCID: PMC9169745 DOI: 10.1073/pnas.2201632119] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Efforts to improve tuberculosis therapy include optimizing multidrug regimens to take advantage of drug–drug synergies. However, the complex host environment has a profound effect on bacterial metabolic state and drug activity, making predictions of optimal drug combinations difficult. In this study, we leverage a newly developed library of conditional knockdown Mycobacterium tuberculosis mutants in which genetic depletion of essential genes mimics the effect of drug therapy. This tractable system allowed us to assess the effect of growth condition on predicted drug–drug interactions. We found that these interactions can be differentially sensitive to the metabolic state, and select in vitro–defined interactions can be leveraged to accelerate bacterial killing during infection. These findings suggest strategies for optimizing tuberculosis therapy. Current chemotherapy against Mycobacterium tuberculosis (Mtb), an important human pathogen, requires a multidrug regimen lasting several months. While efforts have been made to optimize therapy by exploiting drug–drug synergies, testing new drug combinations in relevant host environments remains arduous. In particular, host environments profoundly affect the bacterial metabolic state and drug efficacy, limiting the accuracy of predictions based on in vitro assays alone. In this study, we utilized conditional Mtb knockdown mutants of essential genes as an experimentally tractable surrogate for drug treatment and probe the relationship between Mtb carbon metabolism and chemical–genetic interactions (CGIs). We examined the antitubercular drugs isoniazid, rifampicin, and moxifloxacin and found that CGIs are differentially responsive to the metabolic state, defining both environment-independent and -dependent interactions. Specifically, growth on the in vivo–relevant carbon source, cholesterol, reduced rifampicin efficacy by altering mycobacterial cell surface lipid composition. We report that a variety of perturbations in cell wall synthesis pathways restore rifampicin efficacy during growth on cholesterol, and that both environment-independent and cholesterol-dependent in vitro CGIs could be leveraged to enhance bacterial clearance in the mouse infection model. Our findings present an atlas of chemical–genetic–environmental interactions that can be used to optimize drug–drug interactions, as well as provide a framework for understanding in vitro correlates of in vivo efficacy.
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8
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Morishita M, Sagayama R, Yamawaki Y, Yamaguchi M, Katsumi H, Yamamoto A. Activation of Host Immune Cells by Probiotic-Derived Extracellular Vesicles via TLR2-Mediated Signaling Pathways. Biol Pharm Bull 2022; 45:354-359. [PMID: 35228401 DOI: 10.1248/bpb.b21-00924] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Since probiotic-derived extracellular vesicles (EVs) are capable of activating innate immunity, they are expected to be useful as novel adjuvants. To elucidate the mechanisms underlying the immunostimulatory effects of EVs released from probiotic cells, we newly investigated the role of Toll-like receptor 2 (TLR2) and immune cell downstream signaling in the generation of proinflammatory cytokines. Isolated Bifidobacterium- and Lactobacillus-derived EVs expressed peptidoglycan, one of the major pathogen-associated molecular patterns. EVs particle diameter were approximately 110-120 nm with a negative-zeta potential. The generation of proinflammatory cytokines (tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in TLR2-expressing mouse macrophage-like RAW264.7 cells and mouse dendritic DC2.4 cells treated with Bifidobacterium- and Lactobacillus-derived EVs decreased after the addition of T2.5, a TLR2 inhibitory antibody. Furthermore, we showed that the signaling pathways of c-Jun-NH2-terminal kinase (JNK)/mitogen-activated protein kinases (MAPK) and nuclear factor-kappaB (NF-κB) were also involved in the production of proinflammatory cytokines from EV-treated immune cells. These results provide valuable information for understanding of the host biological function induced by probiotic-derived EVs, which is helpful for developing an EV-based immunotherapeutic system.
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Affiliation(s)
| | - Risa Sagayama
- Department of Biopharmaceutics, Kyoto Pharmaceutical University
| | - Yuta Yamawaki
- Department of Biopharmaceutics, Kyoto Pharmaceutical University
| | | | | | - Akira Yamamoto
- Department of Biopharmaceutics, Kyoto Pharmaceutical University
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9
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Flores J, Cancino JC, Chavez-Galan L. Lipoarabinomannan as a Point-of-Care Assay for Diagnosis of Tuberculosis: How Far Are We to Use It? Front Microbiol 2021; 12:638047. [PMID: 33935997 PMCID: PMC8081860 DOI: 10.3389/fmicb.2021.638047] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 03/22/2021] [Indexed: 12/13/2022] Open
Abstract
Tuberculosis (TB) is still a severe public health problem; the current diagnostic tests have limitations that delay treatment onset. Lipoarabinomannan (LAM) is a glycolipid that is a component of the cell wall of the bacillus Mycobacterium tuberculosis, the etiologic agent of TB. This glycolipid is excreted as a soluble form in urine. The World Health Organization has established that the design of new TB diagnostic methods is one of the priorities within the EndTB Strategy. LAM has been suggested as a biomarker to develop diagnostic tests based on its identification in urine, and it is one of the most prominent candidates to develop point-of-care diagnostic test because urine samples can be easily collected. Moreover, LAM can regulate the immune response in the host and can be found in the serum of TB patients, where it probably affects a wide variety of host cell populations, consequently influencing the quality of both innate and adaptive immune responses during TB infection. Here, we revised the evidence that supports that LAM could be used as a tool for the development of new point-of-care tests for TB diagnosis, and we discussed the mechanisms that could contribute to the low sensitivity of diagnostic testing.
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Affiliation(s)
- Julio Flores
- Laboratory of Integrative Immunology, Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas, Mexico City, Mexico.,Laboratory of Immunomicrobiology, Department of Microbiology, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Juan Carlos Cancino
- Laboratory of Immunomicrobiology, Department of Microbiology, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Leslie Chavez-Galan
- Laboratory of Integrative Immunology, Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas, Mexico City, Mexico
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10
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The thick waxy coat of mycobacteria, a protective layer against antibiotics and the host's immune system. Biochem J 2020; 477:1983-2006. [PMID: 32470138 PMCID: PMC7261415 DOI: 10.1042/bcj20200194] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/30/2020] [Accepted: 05/04/2020] [Indexed: 12/22/2022]
Abstract
Tuberculosis, caused by the pathogenic bacterium Mycobacterium tuberculosis (Mtb), is the leading cause of death from an infectious disease, with a mortality rate of over a million people per year. This pathogen's remarkable resilience and infectivity is largely due to its unique waxy cell envelope, 40% of which comprises complex lipids. Therefore, an understanding of the structure and function of the cell wall lipids is of huge indirect clinical significance. This review provides a synopsis of the cell envelope and the major lipids contained within, including structure, biosynthesis and roles in pathogenesis.
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11
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Batt SM, Burke CE, Moorey AR, Besra GS. Antibiotics and resistance: the two-sided coin of the mycobacterial cell wall. Cell Surf 2020; 6:100044. [PMID: 32995684 PMCID: PMC7502851 DOI: 10.1016/j.tcsw.2020.100044] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/26/2020] [Accepted: 08/26/2020] [Indexed: 01/07/2023] Open
Abstract
Mycobacterium tuberculosis, the bacterium responsible for tuberculosis, is the global leading cause of mortality from an infectious agent. Part of this success relies on the unique cell wall, which consists of a thick waxy coat with tightly packed layers of complexed sugars, lipids and peptides. This coat provides a protective hydrophobic barrier to antibiotics and the host's defences, while enabling the bacterium to spread efficiently through sputum to infect and survive within the macrophages of new hosts. However, part of this success comes at a cost, with many of the current first- and second-line drugs targeting the enzymes involved in cell wall biosynthesis. The flip side of this coin is that resistance to these drugs develops either in the target enzymes or the activation pathways of the drugs, paving the way for new resistant clinical strains. This review provides a synopsis of the structure and synthesis of the cell wall and the major current drugs and targets, along with any mechanisms of resistance.
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Affiliation(s)
- Sarah M. Batt
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Christopher E. Burke
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Alice R. Moorey
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Gurdyal S. Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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12
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Justen AM, Hodges HL, Kim LM, Sadecki PW, Porfirio S, Ultee E, Black I, Chung GS, Briegel A, Azadi P, Kiessling LL. Polysaccharide length affects mycobacterial cell shape and antibiotic susceptibility. SCIENCE ADVANCES 2020; 6:6/38/eaba4015. [PMID: 32938674 PMCID: PMC7494350 DOI: 10.1126/sciadv.aba4015] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 08/05/2020] [Indexed: 05/04/2023]
Abstract
Bacteria control the length of their polysaccharides, which can control cell viability, physiology, virulence, and immune evasion. Polysaccharide chain length affects immunomodulation, but its impact on bacterial physiology and antibiotic susceptibility was unclear. We probed the consequences of truncating the mycobacterial galactan, an essential linear polysaccharide of about 30 residues. Galactan covalently bridges cell envelope layers, with the outermost cell wall linkage point occurring at residue 12. Reducing galactan chain length by approximately half compromises fitness, alters cell morphology, and increases the potency of hydrophobic antibiotics. Systematic variation of the galactan chain length revealed that it determines periplasm size. Thus, glycan chain length can directly affect cellular physiology and antibiotic activity, and mycobacterial glycans, not proteins, regulate periplasm size.
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Affiliation(s)
- Alexander M Justen
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706-1544, USA
| | - Heather L Hodges
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1322, USA
| | - Lili M Kim
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706-1544, USA
| | - Patric W Sadecki
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1322, USA
| | - Sara Porfirio
- Complex Carbohydrate Research Center, 315 Riverbend Rd, Athens, GA 30602, USA
| | - Eveline Ultee
- Institute of Biology, University of Leiden, 2333 BE Leiden, Netherlands
| | - Ian Black
- Complex Carbohydrate Research Center, 315 Riverbend Rd, Athens, GA 30602, USA
| | - Grace S Chung
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706-1544, USA
| | - Ariane Briegel
- Institute of Biology, University of Leiden, 2333 BE Leiden, Netherlands
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, 315 Riverbend Rd, Athens, GA 30602, USA
| | - Laura L Kiessling
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706-1544, USA
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1322, USA
- The Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
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13
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Araújo CL, Blanco I, Souza L, Tiwari S, Pereira LC, Ghosh P, Azevedo V, Silva A, Folador A. In silico functional prediction of hypothetical proteins from the core genome of Corynebacterium pseudotuberculosis biovar ovis. PeerJ 2020; 8:e9643. [PMID: 32913672 PMCID: PMC7456259 DOI: 10.7717/peerj.9643] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 07/10/2020] [Indexed: 12/30/2022] Open
Abstract
Corynebacterium pseudotuberculosis is a pathogen of veterinary relevance diseases, being divided into two biovars: equi and ovis; causing ulcerative lymphangitis and caseous lymphadenitis, respectively. The isolation and sequencing of C. pseudotuberculosis biovar ovis strains in the Northern and Northeastern regions of Brazil exhibited the emergence of this pathogen, which causes economic losses to small ruminant producers, and condemnation of carcasses and skins of animals. Through the pan-genomic approach, it is possible to determine and analyze genes that are shared by all strains of a species—the core genome. However, many of these genes do not have any predicted function, being characterized as hypothetical proteins (HP). In this study, we considered 32 C. pseudotuberculosis biovar ovis genomes for the pan-genomic analysis, where were identified 172 HP present in a core genome composed by 1255 genes. We are able to functionally annotate 80 sequences previously characterized as HP through the identification of structural features as conserved domains and families. Furthermore, we analyzed the physicochemical properties, subcellular localization and molecular function. Additionally, through RNA-seq data, we investigated the differential gene expression of the annotated HP. Genes inserted in pathogenicity islands had their virulence potential evaluated. Also, we have analyzed the existence of functional associations for their products based on protein–protein interaction networks, and perform the structural prediction of three targets. Due to the integration of different strategies, this study can underlie deeper in vitro researches in the characterization of these HP and the search for new solutions for combat this pathogen.
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Affiliation(s)
- Carlos Leonardo Araújo
- Laboratory of Genomics and Bioinformatics, Center of Genomics and Systems Biology, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil
| | - Iago Blanco
- Laboratory of Genomics and Bioinformatics, Center of Genomics and Systems Biology, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil
| | - Luciana Souza
- Laboratory of Genomics and Bioinformatics, Center of Genomics and Systems Biology, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil
| | - Sandeep Tiwari
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Lino César Pereira
- Laboratory of Genomics and Bioinformatics, Center of Genomics and Systems Biology, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil
| | - Preetam Ghosh
- Department of Computer Science, Virginia Commonwealth University, Richmond, VA, USA
| | - Vasco Azevedo
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Artur Silva
- Laboratory of Genomics and Bioinformatics, Center of Genomics and Systems Biology, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil
| | - Adriana Folador
- Laboratory of Genomics and Bioinformatics, Center of Genomics and Systems Biology, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil
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Characterization of Arabinosyl Transfer Reactions in the Biosynthesis of Mycobacterial Cell Envelope (Lipo)Polysaccharides. Methods Mol Biol 2019. [PMID: 30864132 DOI: 10.1007/978-1-4939-9154-9_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
D-Arabinofuranose is a major glycosyl constituent of mycobacteria found in two essential cell envelope heteropolysaccharides, arabinogalactan and lipoarabinomannan. Seven different arabinosyltransferases at least are required to synthesize the arabinan domain of these two major glycans. Because of their interest from the perspective of drug development, these enzymes have been the object of intense investigations. In this chapter, we describe the protocols used to perform nonradioactive arabinosyltransferase assays with synthetic acceptor and donor substrates and characterize the enzymatic products of the reactions by mass spectrometry.
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15
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Wang L, Guo Z. An extensive review of studies on mycobacterium cell wall polysaccharide-related oligosaccharides – part I: Synthetic studies on arabinofuranosyl oligosaccharides. J Carbohydr Chem 2019. [DOI: 10.1080/07328303.2019.1630839] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- 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, USA
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16
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Abstract
Actinobacteria is a group of diverse bacteria. Most species in this class of bacteria are filamentous aerobes found in soil, including the genus Streptomyces perhaps best known for their fascinating capabilities of producing antibiotics. These bacteria typically have a Gram-positive cell envelope, comprised of a plasma membrane and a thick peptidoglycan layer. However, there is a notable exception of the Corynebacteriales order, which has evolved a unique type of outer membrane likely as a consequence of convergent evolution. In this chapter, we will focus on the unique cell envelope of this order. This cell envelope features the peptidoglycan layer that is covalently modified by an additional layer of arabinogalactan . Furthermore, the arabinogalactan layer provides the platform for the covalent attachment of mycolic acids , some of the longest natural fatty acids that can contain ~100 carbon atoms per molecule. Mycolic acids are thought to be the main component of the outer membrane, which is composed of many additional lipids including trehalose dimycolate, also known as the cord factor. Importantly, a subset of bacteria in the Corynebacteriales order are pathogens of human and domestic animals, including Mycobacterium tuberculosis. The surface coat of these pathogens are the first point of contact with the host immune system, and we now know a number of host receptors specific to molecular patterns exposed on the pathogen's surface, highlighting the importance of understanding how the cell envelope of Actinobacteria is structured and constructed. This chapter describes the main structural and biosynthetic features of major components found in the actinobacterial cell envelopes and highlights the key differences between them.
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Affiliation(s)
- Kathryn C Rahlwes
- Department of Microbiology, University of Massachusetts, 639 North Pleasant Street, Amherst, MA, 01003, USA
| | - Ian L Sparks
- Department of Microbiology, University of Massachusetts, 639 North Pleasant Street, Amherst, MA, 01003, USA
| | - Yasu S Morita
- Department of Microbiology, University of Massachusetts, 639 North Pleasant Street, Amherst, MA, 01003, USA.
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17
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The singular Corynebacterium glutamicum Emb arabinofuranosyltransferase polymerises the α(1 → 5) arabinan backbone in the early stages of cell wall arabinan biosynthesis. ACTA ACUST UNITED AC 2018; 2:38-53. [PMID: 30046665 PMCID: PMC6053596 DOI: 10.1016/j.tcsw.2018.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 06/14/2018] [Accepted: 06/15/2018] [Indexed: 11/20/2022]
Abstract
The arabinan-containing polysaccharides, arabinogalactan (AG) and lipoarabinomannan (LAM), are key cell wall components of the Corynebacterineae, which include Corynebacteria, Norcadia and Mycobacteria. Both AG and LAM contain elaborate arabinan domains composed of distinct structural motifs. Mycobacterial EmbA, EmbB and EmbC, collectively known as the Emb proteins, have been identified as arabinosyltransferases (ArafTs), which are targeted by the front-line anti-tubercular drug ethambutol. Previous studies have established that EmbA and EmbB play a role in the synthesis of the characteristic terminal hexa-arabinosuranosyl motif, whilst EmbC is involved exclusively in the biosynthesis of LAM. Herein, we have investigated the role of the singular Emb protein from Corynebacterium glutamicum through the detailed biochemical and chemical analysis of a double ΔaftAΔemb mutant, where the priming Cg-AftA protein, which generates the substrate for Cg-Emb has been deleted. Analysis of its cell wall revealed a complete absence of arabinose resulting in a truncated cell wall containing only a galactan backbone accompanied with complete loss of cell wall bound mycolates. In vitro cell-free assays using C. glutamicumΔaftA, C. glutamicumΔemb, C. glutamicumΔaftAΔemb and C. glutamicumΔaftBΔaftD and two synthetic acceptors, which mimick the arabinofuranose (Araf) “primed” galactan chain, demonstrated that Cg-Emb is able to transfer an Araf residue to the C5 of the Araf positioned on the synthetic acceptor(s). These results indicate that Cg-Emb acts as an α(1 → 5) ArafT and elongates the arabinan core during the early stages of arabinan biosynthesis in C. glutamicum.
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18
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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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