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Ye X, Paul B, Mo J, Reynolds EC, Ghosal D, Veith PD. Ultrastructural and glycoproteomic characterization of Prevotella intermedia: Insights into O-glycosylation and outer membrane vesicles. Microbiologyopen 2024; 13:e1401. [PMID: 38409911 PMCID: PMC10897501 DOI: 10.1002/mbo3.1401] [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: 12/11/2023] [Revised: 02/08/2024] [Accepted: 02/16/2024] [Indexed: 02/28/2024] Open
Abstract
Prevotella intermedia, a Gram-negative bacterium from the Bacteroidota phylum, is associated with periodontitis. Other species within this phylum are known to possess the general O-glycosylation system. The O-glycoproteome has been characterized in several species, including Tannerella forsythia, Porphyromonas gingivalis, and Flavobacterium johnsoniae. In our study, we used electron cryotomography (cryoET) and glycoproteomics to reveal the ultrastructure of P. intermedia and characterize its O-glycoproteome. Our cryoET analysis unveiled the ultrastructural details of the cell envelope and outer membrane vesicles (OMVs) of P. intermedia. We observed an electron-dense surface layer surrounding both cells and OMVs. The OMVs were often large (>200 nm) and presented two types, with lumens being either electron-dense or translucent. LC-MS/MS analyses of P. intermedia fractions led to the identification of 1655 proteins, which included 62 predicted T9SS cargo proteins. Within the glycoproteome, we identified 443 unique O-glycosylation sites within 224 glycoproteins. Interestingly, the O-glycosylation motif exhibited a broader range than reported in other species, with O-glycosylation found at D(S/T)(A/I/L/M/T/V/S/C/G/F/N/E/Q/D/P). We identified a single O-glycan with a delta mass of 1531.48 Da. Its sequence was determined by MS2 and MS3 analyses using both collision-induced dissociation and high-energy collisional dissociation fragmentation modes. After partial deglycosylation with trifluoromethanesulfonic acid, the O-glycan sequence was confirmed to be dHex-dHex-HexNAc (HPO3 -C6 H12 O5 )-dHex-Hex-HexA-Hex(dHex). Bioinformatic analyses predicted the localization of O-glycoproteins, with 73 periplasmic proteins, 53 inner membrane proteins, 52 lipoproteins, 26 outer membrane proteins, and 14 proteins secreted by the T9SS.
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Affiliation(s)
- Xi Ye
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology InstituteThe University of MelbourneMelbourneVictoriaAustralia
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 InstituteThe University of MelbourneParkvilleVictoriaAustralia
| | - Bindusmita Paul
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology InstituteThe University of MelbourneMelbourneVictoriaAustralia
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 InstituteThe University of MelbourneParkvilleVictoriaAustralia
| | - Joyce Mo
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology InstituteThe University of MelbourneMelbourneVictoriaAustralia
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 InstituteThe University of MelbourneParkvilleVictoriaAustralia
| | - Eric C. Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 InstituteThe University of MelbourneParkvilleVictoriaAustralia
| | - Debnath Ghosal
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology InstituteThe University of MelbourneMelbourneVictoriaAustralia
- ARC Centre for Cryo‐electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology InstituteUniversity of MelbourneParkvilleVictoriaAustralia
| | - Paul D. Veith
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 InstituteThe University of MelbourneParkvilleVictoriaAustralia
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Hager-Mair FF, Bloch S, Schäffer C. Glycolanguage of the oral microbiota. Mol Oral Microbiol 2024. [PMID: 38515284 DOI: 10.1111/omi.12456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 02/13/2024] [Accepted: 02/13/2024] [Indexed: 03/23/2024]
Abstract
The oral cavity harbors a diverse and dynamic bacterial biofilm community which is pivotal to oral health maintenance and, if turning dysbiotic, can contribute to various diseases. Glycans as unsurpassed carriers of biological information are participating in underlying processes that shape oral health and disease. Bacterial glycoinfrastructure-encompassing compounds as diverse as glycoproteins, lipopolysaccharides (LPSs), cell wall glycopolymers, and exopolysaccharides-is well known to influence bacterial fitness, with direct effects on bacterial physiology, immunogenicity, lifestyle, and interaction and colonization capabilities. Thus, understanding oral bacterias' glycoinfrastructure and encoded glycolanguage is key to elucidating their pathogenicity mechanisms and developing targeted strategies for therapeutic intervention. Driven by their known immunological role, most research in oral glycobiology has been directed onto LPSs, whereas, recently, glycoproteins have been gaining increased interest. This review draws a multifaceted picture of the glycolanguage, with a focus on glycoproteins, manifested in prominent oral bacteria, such as streptococci, Porphyromonas gingivalis, Tannerella forsythia, and Fusobacterium nucleatum. We first define the characteristics of the different glycoconjugate classes and then summarize the current status of knowledge of the structural diversity of glycoconjugates produced by oral bacteria, describe governing biosynthetic pathways, and list biological roles of these energetically costly compounds. Additionally, we highlight emerging research on the unraveling impact of oral glycoinfrastructure on dental caries, periodontitis, and systemic conditions. By integrating current knowledge and identifying knowledge gaps, this review underscores the importance of studying the glycolanguage oral bacteria speak to advance our understanding of oral microbiology and develop novel antimicrobials.
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Affiliation(s)
- Fiona F Hager-Mair
- Department of Chemistry, NanoGlycobiology Research Group, Institute of Biochemistry, Universität für Bodenkultur Wien, Vienna, Austria
| | - Susanne Bloch
- Department of Chemistry, NanoGlycobiology Research Group, Institute of Biochemistry, Universität für Bodenkultur Wien, Vienna, Austria
- Competence Center for Periodontal Research, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria
| | - Christina Schäffer
- Department of Chemistry, NanoGlycobiology Research Group, Institute of Biochemistry, Universität für Bodenkultur Wien, Vienna, Austria
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Veith PD, Gorasia DG, Reynolds EC. Characterization of the O-Glycoproteome of Flavobacterium johnsoniae. J Bacteriol 2023; 205:e0009323. [PMID: 37162352 PMCID: PMC10294664 DOI: 10.1128/jb.00093-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 04/17/2023] [Indexed: 05/11/2023] Open
Abstract
Flavobacterium johnsoniae is a free-living member of the Bacteroidota phylum that is found in soil and water. It is frequently used as a model species for studying a type of gliding motility dependent on the type IX secretion system (T9SS). O-Glycosylation has been reported in several Bacteroidota species, and the O-glycosylation of S-layer proteins in Tannerella forsythia was shown to be important for certain virulence features. In this study, we characterized the O-glycoproteome of F. johnsoniae and identified 325 O-glycosylation sites within 226 glycoproteins. The structure of the major glycan was found to be a hexasaccharide with the sequence Hex-(Me-dHex)-Me-HexA-Pent-HexA-Me-HexNAcA. Bioinformatic localization of the glycoproteins predicted 68 inner membrane proteins, 60 periplasmic proteins, 26 outer membrane proteins, 57 lipoproteins, and 9 proteins secreted by the T9SS. The glycosylated sites were predominantly located in the periplasm, where they are postulated to be beneficial for protein folding/stability. Six proteins associated with gliding motility or the T9SS were demonstrated to be O-glycosylated. IMPORTANCE Flavobacterium johnsoniae is a Gram-negative bacterium that is found in soil and water. It is frequently used as a model species for studying gliding motility and the T9SS. In this study, we characterized the O-glycoproteome of F. johnsoniae and identified 325 O-glycosylation sites within 226 glycoproteins. The glycosylated domains were mainly localized to the periplasm. The function of O-glycosylation is likely related to protein folding and stability; therefore, the finding of the glycosylation sites has relevance for studies involving expression of the proteins. Six proteins associated with gliding motility or the T9SS were demonstrated to be O-glycosylated, which may impact the structure and function of these components.
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Affiliation(s)
- Paul D. Veith
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Dhana G. Gorasia
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Eric C. Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
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4
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Kendlbacher FL, Bloch S, Hager‐Mair FF, Bacher J, Janesch B, Thurnheer T, Andrukhov O, Schäffer C. Multispecies biofilm behavior and host interaction support the association of Tannerella serpentiformis with periodontal health. Mol Oral Microbiol 2023; 38:115-133. [PMID: 35964247 PMCID: PMC10947601 DOI: 10.1111/omi.12385] [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: 06/13/2022] [Revised: 07/15/2022] [Accepted: 08/09/2022] [Indexed: 11/27/2022]
Abstract
The recently identified bacterium Tannerella serpentiformis is the closest phylogenetic relative of Tannerella forsythia, whose presence in oral biofilms is associated with periodontitis. Conversely, T. serpentiformis is considered health-associated. This discrepancy was investigated in a comparative study of the two Tannerella species. The biofilm behavior was analyzed upon their addition and of Porphyromonas gingivalis-each bacterium separately or in combinations-to an in vitro five-species oral model biofilm. Biofilm composition and architecture was analyzed quantitatively using real-time PCR and qualitatively by fluorescence in situ hybridization/confocal laser scanning microscopy, and by scanning electron microscopy. The presence of T. serpentiformis led to a decrease of the total cell number of biofilm bacteria, while P. gingivalis was growth-promoting. This effect was mitigated by T. serpentiformis when added to the biofilm together with P. gingivalis. Notably, T. serpentiformis outcompeted T. forsythia numbers when the two species were simultaneously added to the biofilm compared to biofilms containing T. forsythia alone. Tannerella serpentiformis appeared evenly distributed throughout the multispecies biofilm, while T. forsythia was surface-located. Adhesion and invasion assays revealed that T. serpentiformis was significantly less effective in invading human gingival epithelial cells than T. forsythia. Furthermore, compared to T. forsythia, a higher immunostimulatory potential of human gingival fibroblasts and macrophages was revealed for T. serpentiformis, based on mRNA expression levels of the inflammatory mediators interleukin 6 (IL-6), IL-8, monocyte chemoattractant protein-1 and tumor necrosis factor α, and production of the corresponding proteins. Collectively, these data support the potential of T. serpentiformis to interfere with biological processes relevant to the establishment of periodontitis.
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Affiliation(s)
- Fabian L. Kendlbacher
- NanoGlycobiology Unit, Department of NanoBiotechnologyUniversität für Bodenkultur WienViennaAustria
| | - Susanne Bloch
- NanoGlycobiology Unit, Department of NanoBiotechnologyUniversität für Bodenkultur WienViennaAustria
| | - Fiona F. Hager‐Mair
- NanoGlycobiology Unit, Department of NanoBiotechnologyUniversität für Bodenkultur WienViennaAustria
| | - Johanna Bacher
- NanoGlycobiology Unit, Department of NanoBiotechnologyUniversität für Bodenkultur WienViennaAustria
| | - Bettina Janesch
- NanoGlycobiology Unit, Department of NanoBiotechnologyUniversität für Bodenkultur WienViennaAustria
| | - Thomas Thurnheer
- Clinic of Conservative and Preventive DentistryDivision of Clinical Oral Microbiology and ImmunologyCenter of Dental MedicineUniversity of ZürichZürichSwitzerland
| | - Oleh Andrukhov
- Competence Center for Periodontal ResearchUniversity Clinic of Dentistry, Medical University of ViennaViennaAustria
| | - Christina Schäffer
- NanoGlycobiology Unit, Department of NanoBiotechnologyUniversität für Bodenkultur WienViennaAustria
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Lewis AL, Toukach P, Bolton E, Chen X, Frank M, Lütteke T, Knirel Y, Schoenhofen I, Varki A, Vinogradov E, Woods RJ, Zachara N, Zhang J, Kamerling JP, Neelamegham S. Cataloging natural sialic acids and other nonulosonic acids (NulOs), and their representation using the Symbol Nomenclature for Glycans. Glycobiology 2023; 33:99-103. [PMID: 36648443 PMCID: PMC9990982 DOI: 10.1093/glycob/cwac072] [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: 07/01/2022] [Revised: 09/14/2022] [Accepted: 10/18/2022] [Indexed: 01/18/2023] Open
Abstract
Nonulosonic acids or non-2-ulosonic acids (NulOs) are an ancient family of 2-ketoaldonic acids (α-ketoaldonic acids) with a 9-carbon backbone. In nature, these monosaccharides occur either in a 3-deoxy form (referred to as "sialic acids") or in a 3,9-dideoxy "sialic-acid-like" form. The former sialic acids are most common in the deuterostome lineage, including vertebrates, and mimicked by some of their pathogens. The latter sialic-acid-like molecules are found in bacteria and archaea. NulOs are often prominently positioned at the outermost tips of cell surface glycans, and have many key roles in evolution, biology and disease. The diversity of stereochemistry and structural modifications among the NulOs contributes to more than 90 sialic acid forms and 50 sialic-acid-like variants described thus far in nature. This paper reports the curation of these diverse naturally occurring NulOs at the NCBI sialic acid page (https://www.ncbi.nlm.nih.gov/glycans/sialic.html) as part of the NCBI-Glycans initiative. This includes external links to relevant Carbohydrate Structure Databases. As the amino and hydroxyl groups of these monosaccharides are extensively derivatized by various substituents in nature, the Symbol Nomenclature For Glycans (SNFG) rules have been expanded to represent this natural diversity. These developments help illustrate the natural diversity of sialic acids and related NulOs, and enable their systematic representation in publications and online resources.
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Affiliation(s)
- Amanda L Lewis
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Glycobiology Research and Training Center, University of California, San Diego, CA 92093, USA
| | - Philip Toukach
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia
| | - Evan Bolton
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Xi Chen
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Martin Frank
- Biognos AB, Generatorsgatan 1/Box 8963, 402 74 Göteborg, Sweden
| | - Thomas Lütteke
- Institute of Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Frankfurter Str. 100, 35392 Giessen, Germany
| | - Yuriy Knirel
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia
| | - Ian Schoenhofen
- Human Health Therapeutics Research Centre, National Research Council of Canada, Ottawa, ON K1A OR6, Canada
| | - Ajit Varki
- Department of Medicine and Cellular & Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, CA 92093, USA
| | - Evgeny Vinogradov
- Human Health Therapeutics Research Centre, National Research Council of Canada, Ottawa, ON K1A OR6, Canada
| | - Robert J Woods
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Natasha Zachara
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jian Zhang
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | | | - Sriram Neelamegham
- Department of Chemical & Biological Engineering, Biomedical Engineering and Medicine, State University of New York, Buffalo, NY 14260, USA
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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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Lim Y, Kim HY, Sun-Jin An, Choi BK. Activation of bone marrow-derived dendritic cells and CD4 + T cell differentiation by outer membrane vesicles of periodontal pathogens. J Oral Microbiol 2022; 14:2123550. [PMID: 36312320 PMCID: PMC9616074 DOI: 10.1080/20002297.2022.2123550] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Outer membrane vesicles (OMVs) released from gram-negative bacteria harbor diverse molecules to communicate with host cells. In this study, we evaluated the OMVs of periodontal pathogens for their effects on the activation of dendritic cells and CD4+ T cell differentiation. OMVs of Porphyromonas gingivalis ATCC 33277, Treponema denticola ATCC 33521, and Tannerella forsythia ATCC 43037 (‘red complex’ pathogens) were isolated by density gradient ultracentrifugation. Mouse bone marrow-derived dendritic cells (BMDCs) were treated with OMVs, and OMV-primed BMDCs were cocultured with naïve CD4+ T cells to analyze the polarization of effector helper T cells. The OMVs upregulated maturation markers, including MHC class II, CD80, CD86, and CD40, on BMDCs. OMVs of P. gingivalis and T. forsythia induced the expression of the proinflammatory cytokines IL-1β, IL-6, IL-23, and IL-12p70 in BMDCs. In T. denticola OMV-primed BMDCs, proinflammatory cytokines were poorly detected, which may be attributed to posttranslational degradation due to the highly proteolytic nature of OMVs. In cocultures of naïve CD4+ T cells with OMV-primed BMDCs, OMVs of P. gingivalis and T. denticola induced the differentiation of Th17 cells, whereas T. forsythia OMVs induced Th1 cell differentiation. These results demonstrate that OMVs derived from the ‘red complex’ periodontal pathogens induce maturation of BMDCs and differentiation of naïve CD4+ T cells to Th1 or Th17 cells.
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Affiliation(s)
- Younggap Lim
- Department of Oral Microbiology and Immunology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Hyun Young Kim
- Department of Oral Microbiology and Immunology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | | | - Bong-Kyu Choi
- Department of Oral Microbiology and Immunology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
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Modulatory Mechanisms of Pathogenicity in Porphyromonas gingivalis and Other Periodontal Pathobionts. Microorganisms 2022; 11:microorganisms11010015. [PMID: 36677306 PMCID: PMC9862357 DOI: 10.3390/microorganisms11010015] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/25/2022] [Accepted: 11/25/2022] [Indexed: 12/24/2022] Open
Abstract
The pathogenesis of periodontitis depends on a sustained feedback loop where bacterial virulence factors and immune responses both contribute to inflammation and tissue degradation. Periodontitis is a multifactorial disease that is associated with a pathogenic shift in the oral microbiome. Within this shift, low-abundance Gram-negative anaerobic pathobionts transition from harmless colonisers of the subgingival environment to a virulent state that drives evasion and subversion of innate and adaptive immune responses. This, in turn, drives the progression of inflammatory disease and the destruction of tooth-supporting structures. From an evolutionary perspective, bacteria have developed this phenotypic plasticity in order to respond and adapt to environmental stimuli or external stressors. This review summarises the available knowledge of genetic, transcriptional, and post-translational mechanisms which mediate the commensal-pathogen transition of periodontal bacteria. The review will focus primarily on Porphyromonas gingivalis.
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Abstract
Porphyromonas gingivalis is an important human pathogen and also a model organism for the Bacteroidetes phylum. O-glycosylation has been reported in this phylum with findings that include the O-glycosylation motif, the structure of the O-glycans in a few species, and an extensive O-glycoproteome analysis in Tannerella forsythia. However, O-glycosylation has not yet been confirmed in P. gingivalis. We therefore used glycoproteomics approaches including partial deglycosylation with trifluoromethanesulfonic acid as well as both HILIC and FAIMS based glycopeptide enrichment strategies leading to the identification of 257 putative glycosylation sites in 145 glycoproteins. The sequence of the major O-glycan was elucidated to be HexNAc-HexNAc(P-Gro-[Ac]0-2)-dHex-Hex-HexA-Hex(dHex). Western blot analyses of mutants lacking the glycosyltransferases PGN_1134 and PGN_1135 demonstrated their involvement in the biosynthesis of the glycan while mass spectrometry analysis of the truncated O-glycans suggested that PGN_1134 and PGN_1135 transfer the two HexNAc sugars. Interestingly, a strong bias against the O-glycosylation of abundant proteins exposed to the cell surface such as abundant T9SS cargo proteins, surface lipoproteins, and outer membrane β-barrel proteins was observed. In contrast, the great majority of proteins associated with the inner membrane or periplasm were glycosylated irrespective of their abundance. The P. gingivalis O-glycosylation system may therefore function to establish the desired physicochemical properties of the periplasm. IMPORTANCEPorphyromonas gingivalis is an oral pathogen primarily associated with severe periodontal disease and further associated with rheumatoid arthritis, dementia, cardiovascular disease, and certain cancers. Protein glycosylation can be important for a variety of reasons including protein function, solubility, protease resistance, and thermodynamic stability. This study has for the first time demonstrated the presence of O-linked glycosylation in this organism by determining the basic structure of the O-glycans and identifying 257 glycosylation sites in 145 proteins. It was found that most proteins exposed to the periplasm were O-glycosylated; however, the abundant surface exposed proteins were not. The O-glycans consisted of seven monosaccharides and a glycerol phosphate with 0–2 acetyl groups. These glycans are likely to have a stabilizing role to the proteins that bear them and must be taken into account when the proteins are produced in heterologous organisms.
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Deng J, Lu C, Zhao Q, Chen K, Ma S, Li Z. The Th17/Treg cell balance: crosstalk among the immune system, bone and microbes in periodontitis. J Periodontal Res 2021; 57:246-255. [PMID: 34878170 DOI: 10.1111/jre.12958] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/04/2021] [Accepted: 11/08/2021] [Indexed: 12/14/2022]
Abstract
Periodontopathic bacteria constantly stimulate the host, which causes an immune response, leading to host-induced periodontal tissue damage. The complex interaction and imbalance between Th17 and Treg cells may be critical in the pathogenesis of periodontitis. Furthermore, the RANKL/RANK/OPG system plays a significant role in periodontitis bone metabolism, and its relationship with the Th17/Treg cell imbalance may be a bridge between periodontal bone metabolism and the immune system. This article reviews the literature related to the Th17/Treg cell imbalance mediated by pathogenic periodontal microbes, and its mechanism involving RANKL/RANK/OPG in periodontitis bone metabolism, in an effort to provide new ideas for the study of the immunopathological mechanism of periodontitis.
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Affiliation(s)
- Jianwen Deng
- Clinical Research Platform for Interdiscipline of Stomatology, The First Affiliated Hospital of Jinan University, Department of Stomatology, College of stomatology, Jinan University, Guangzhou, China
| | - Chunting Lu
- Science and Education Office, The First Affiliated Hospital, Jinan University, Guangzhou, China
| | - Qingtong Zhao
- Clinical Research Platform for Interdiscipline of Stomatology, The First Affiliated Hospital of Jinan University, Department of Stomatology, College of stomatology, Jinan University, Guangzhou, China
| | - Kexiao Chen
- Clinical Research Platform for Interdiscipline of Stomatology, The First Affiliated Hospital of Jinan University, Department of Stomatology, College of stomatology, Jinan University, Guangzhou, China
| | - Shuyuan Ma
- Clinical Research Platform for Interdiscipline of Stomatology, The First Affiliated Hospital of Jinan University, Department of Stomatology, College of stomatology, Jinan University, Guangzhou, China
| | - Zejian Li
- Clinical Research Platform for Interdiscipline of Stomatology, The First Affiliated Hospital of Jinan University, Department of Stomatology, College of stomatology, Jinan University, Guangzhou, China.,Chaoshan Hospital, The First Affiliated Hospital of Jinan University, Jinan University, Chaozhou, China
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11
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Tomek MB, Janesch B, Braun ML, Taschner M, Figl R, Grünwald-Gruber C, Coyne MJ, Blaukopf M, Altmann F, Kosma P, Kählig H, Comstock LE, Schäffer C. A Combination of Structural, Genetic, Phenotypic and Enzymatic Analyses Reveals the Importance of a Predicted Fucosyltransferase to Protein O-Glycosylation in the Bacteroidetes. Biomolecules 2021; 11:1795. [PMID: 34944439 PMCID: PMC8698959 DOI: 10.3390/biom11121795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/21/2021] [Accepted: 11/23/2021] [Indexed: 12/20/2022] Open
Abstract
Diverse members of the Bacteroidetes phylum have general protein O-glycosylation systems that are essential for processes such as host colonization and pathogenesis. Here, we analyzed the function of a putative fucosyltransferase (FucT) family that is widely encoded in Bacteroidetes protein O-glycosylation genetic loci. We studied the FucT orthologs of three Bacteroidetes species-Tannerella forsythia, Bacteroides fragilis, and Pedobacter heparinus. To identify the linkage created by the FucT of B. fragilis, we elucidated the full structure of its nine-sugar O-glycan and found that l-fucose is linked β1,4 to glucose. Of the two fucose residues in the T. forsythia O-glycan, the fucose linked to the reducing-end galactose was shown by mutational analysis to be l-fucose. Despite the transfer of l-fucose to distinct hexose sugars in the B. fragilis and T. forsythia O-glycans, the FucT orthologs from B. fragilis, T. forsythia, and P. heparinus each cross-complement the B. fragilis ΔBF4306 and T. forsythia ΔTanf_01305 FucT mutants. In vitro enzymatic analyses showed relaxed acceptor specificity of the three enzymes, transferring l-fucose to various pNP-α-hexoses. Further, glycan structural analysis together with fucosidase assays indicated that the T. forsythia FucT links l-fucose α1,6 to galactose. Given the biological importance of fucosylated carbohydrates, these FucTs are promising candidates for synthetic glycobiology.
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Affiliation(s)
- Markus B. Tomek
- NanoGlycobiology Unit, Institute of Biologically Inspired Materials, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria; (M.B.T.); (B.J.); (M.L.B.); (M.T.)
| | - Bettina Janesch
- NanoGlycobiology Unit, Institute of Biologically Inspired Materials, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria; (M.B.T.); (B.J.); (M.L.B.); (M.T.)
| | - Matthias L. Braun
- NanoGlycobiology Unit, Institute of Biologically Inspired Materials, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria; (M.B.T.); (B.J.); (M.L.B.); (M.T.)
| | - Manfred Taschner
- NanoGlycobiology Unit, Institute of Biologically Inspired Materials, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria; (M.B.T.); (B.J.); (M.L.B.); (M.T.)
| | - Rudolf Figl
- Institute of Biochemistry, Department of Chemistry, Universität für Bodenkultur Wien, Muthgasse 18, A-1190 Vienna, Austria; (R.F.); (C.G.-G.); (F.A.)
| | - Clemens Grünwald-Gruber
- Institute of Biochemistry, Department of Chemistry, Universität für Bodenkultur Wien, Muthgasse 18, A-1190 Vienna, Austria; (R.F.); (C.G.-G.); (F.A.)
| | - Michael J. Coyne
- Department of Microbiology and the Duchossois Family Institute, University of Chicago, KCBD, 900 E. 57th Street, Chicago, IL 60637, USA; (M.J.C.); (L.E.C.)
| | - Markus Blaukopf
- Institute of Organic Chemistry, Department of Chemistry, Universität für Bodenkultur Wien, Muthgasse 18, A-1190 Vienna, Austria; (M.B.); (P.K.)
| | - Friedrich Altmann
- Institute of Biochemistry, Department of Chemistry, Universität für Bodenkultur Wien, Muthgasse 18, A-1190 Vienna, Austria; (R.F.); (C.G.-G.); (F.A.)
| | - Paul Kosma
- Institute of Organic Chemistry, Department of Chemistry, Universität für Bodenkultur Wien, Muthgasse 18, A-1190 Vienna, Austria; (M.B.); (P.K.)
| | - Hanspeter Kählig
- Department of Organic Chemistry, Faculty of Chemistry, University of Vienna, Währinger Strasse 38, A-1090 Vienna, Austria;
| | - Laurie E. Comstock
- Department of Microbiology and the Duchossois Family Institute, University of Chicago, KCBD, 900 E. 57th Street, Chicago, IL 60637, USA; (M.J.C.); (L.E.C.)
| | - Christina Schäffer
- NanoGlycobiology Unit, Institute of Biologically Inspired Materials, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria; (M.B.T.); (B.J.); (M.L.B.); (M.T.)
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Abstract
Tannerella forsythia is a Gram-negative oral pathogen known to possess an O-glycosylation system responsible for targeting multiple proteins associated with virulence at the three-residue motif (D)(S/T)(A/I/L/V/M/T). Multiple proteins have been identified to be decorated with a decasaccharide glycan composed of a poorly defined core plus a partially characterized species-specific section. To date, glycosylation studies have focused mainly on the two S-layer glycoproteins, TfsA and TfsB, so the true extent of glycosylation within this species has not been fully explored. In the present study, we characterize the glycoproteome of T. forsythia by employing FAIMS-based glycopeptide enrichment of a cell membrane fraction. We demonstrate that at least 13 glycans are utilized within the T. forsythia glycoproteome, varying with respect to the presence of the three terminal sugars and the presence of fucose and digitoxose residues at the reducing end. To improve the localization of glycosylation events and enhance the detection of glycopeptides, we utilized trifluoromethanesulfonic acid treatment to allow the selective chemical cleavage of glycans. Reducing the chemical complexity of glycopeptides dramatically improved the number of glycopeptides identified and our ability to localize glycosylation sites by ETD fragmentation, leading to the identification of 312 putative glycosylation sites in 145 glycoproteins. Glycosylation site analysis revealed that glycosylation occurs on a much broader motif than initially reported, with glycosylation found at (D)(S/T)(A/I/L/V/M/T/S/C/G/F). The prevalence of this broader glycosylation motif in the genome suggests the existence of hundreds of potential O-glycoproteins in this organism. IMPORTANCETannerella forsythia is an oral pathogen associated with severe forms of periodontal disease characterized by destruction of the tooth’s supporting tissues, including the bone. The bacterium releases a variety of proteins associated with virulence on the surface of outer membrane vesicles. There is evidence that these proteins are modified by glycosylation, and this modification is essential for virulence in producing disease. We have utilized novel techniques coupled with mass spectrometry to identify over 13 glycans and 312 putative glycosylation sites in 145 glycoproteins within T. forsythia. Glycosylation site analysis revealed that this modification occurs on a much broader motif than initially reported such that there is a high prevalence of potential glycoproteins in this organism that may help to explain its role in periodontal disease.
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The Intriguing Interaction of Escherichia coli with the Host Environment and Innovative Strategies To Interfere with Colonization: a Summary of the 2019 E. coli and the Mucosal Immune System Meeting. Appl Environ Microbiol 2020; 86:AEM.02085-20. [PMID: 33008822 DOI: 10.1128/aem.02085-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The third E. coli and the Mucosal Immune System (ECMIS) meeting was held at Ghent University in Belgium from 2 to 5 June 2019. It brought together an international group of scientists interested in mechanisms of colonization, host response, and vaccine development. ECMIS distinguishes itself from related meetings on these enteropathogens by providing a greater emphasis on animal health and disease and covering a broad range of pathotypes, including enterohemorrhagic, enteropathogenic, enterotoxigenic, enteroaggregative, and extraintestinal pathogenic Escherichia coli As it is well established that the genus Shigella represents a subspecies of E. coli, these organisms along with related enteroinvasive E. coli are also included. In addition, Tannerella forsythia, a periodontal pathogen, was presented as an example of a pathogen which uses its surface glycans for mucosal interaction. This review summarizes several highlights from the 2019 meeting and major advances to our understanding of the biology of these pathogens and their impact on the host.
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Zou Y, Zheng WB, He JJ, Elsheikha HM, Zhu XQ, Lu YX. Toxocara canis Differentially Affects Hepatic MicroRNA Expression in Beagle Dogs at Different Stages of Infection. Front Vet Sci 2020; 7:587273. [PMID: 33282932 PMCID: PMC7689213 DOI: 10.3389/fvets.2020.587273] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 10/01/2020] [Indexed: 01/25/2023] Open
Abstract
Toxocara canis is a neglected zoonotic parasite, which threatens the health of dogs and humans worldwide. The molecular mechanisms that underlie the progression of T. canis infection remain mostly unknown. MicroRNAs (miRNAs) are small non-coding RNAs that have been identified in T. canis; however, the regulation and role of miRNAs in the host during infection remain incompletely understood. In this study, we determined hepatic miRNA expression at different stages of T. canis infection in beagle dogs. Individual dogs were infected by 300 embryonated T. canis eggs, and their livers were collected at 12 hpi (hours post-infection), 24 hpi, and 36 dpi (days post-infection). The expression profiles of liver miRNAs were determined using RNA-sequencing. Compared to the control groups, 9, 16, and 34 differentially expressed miRNAs (DEmiRNAs) were detected in the livers of infected dogs at the three infection stages, respectively. Among those DEmiRNAs, the novel-294 and cfa-miR-885 were predicted to regulate inflammation-related genes at the initial stage of infection (12 hpi). The cfa-miR-1839 was predicted to regulate the target gene TRIM71, which may influence the development of T. canis larvae at 24 hpi. Moreover, cfa-miR-370 and cfa-miR-133c were associated with immune response at the final stage of infection (36 dpi). Some immunity-related Gene Ontology terms were enriched particularly at 24 hpi. Likewise, Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that many significantly enriched pathways were involved in inflammation and immune responses. The expression level of nine DEmiRNAs was validated using quantitative real-time PCR (qRT-PCR). These results show that miRNAs play critical roles in the pathogenesis of T. canis during the hepatic phase of parasite development. Our data provide fundamental information for further investigation of the roles of miRNAs in the innate/adaptive immune response of dogs infected by T. canis.
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Affiliation(s)
- Yang Zou
- Heilongjiang Key Laboratory for Zoonosis, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
| | - Wen-Bin Zheng
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Jun-Jun He
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Loughborough, United Kingdom
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China.,College of Veterinary Medicine, Shanxi Agricultural University, Taigu, China
| | - Yi-Xin Lu
- Heilongjiang Key Laboratory for Zoonosis, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
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15
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Zwickl NF, Stralis-Pavese N, Schäffer C, Dohm JC, Himmelbauer H. Comparative genome characterization of the periodontal pathogen Tannerella forsythia. BMC Genomics 2020; 21:150. [PMID: 32046654 PMCID: PMC7014623 DOI: 10.1186/s12864-020-6535-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 01/23/2020] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Tannerella forsythia is a bacterial pathogen implicated in periodontal disease. Numerous virulence-associated T. forsythia genes have been described, however, it is necessary to expand the knowledge on T. forsythia's genome structure and genetic repertoire to further elucidate its role within pathogenesis. Tannerella sp. BU063, a putative periodontal health-associated sister taxon and closest known relative to T. forsythia is available for comparative analyses. In the past, strain confusion involving the T. forsythia reference type strain ATCC 43037 led to discrepancies between results obtained from in silico analyses and wet-lab experimentation. RESULTS We generated a substantially improved genome assembly of T. forsythia ATCC 43037 covering 99% of the genome in three sequences. Using annotated genomes of ten Tannerella strains we established a soft core genome encompassing 2108 genes, based on orthologs present in > = 80% of the strains analysed. We used a set of known and hypothetical virulence factors for comparisons in pathogenic strains and the putative periodontal health-associated isolate Tannerella sp. BU063 to identify candidate genes promoting T. forsythia's pathogenesis. Searching for pathogenicity islands we detected 38 candidate regions in the T. forsythia genome. Only four of these regions corresponded to previously described pathogenicity islands. While the general protein O-glycosylation gene cluster of T. forsythia ATCC 43037 has been described previously, genes required for the initiation of glycan synthesis are yet to be discovered. We found six putative glycosylation loci which were only partially conserved in other bacteria. Lastly, we performed a comparative analysis of translational bias in T. forsythia and Tannerella sp. BU063 and detected highly biased genes. CONCLUSIONS We provide resources and important information on the genomes of Tannerella strains. Comparative analyses enabled us to assess the suitability of T. forsythia virulence factors as therapeutic targets and to suggest novel putative virulence factors. Further, we report on gene loci that should be addressed in the context of elucidating T. forsythia's protein O-glycosylation pathway. In summary, our work paves the way for further molecular dissection of T. forsythia biology in general and virulence of this species in particular.
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Affiliation(s)
- Nikolaus F. Zwickl
- Department of Biotechnology, Institute of Computational Biology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Nancy Stralis-Pavese
- Department of Biotechnology, Institute of Computational Biology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Christina Schäffer
- Department of NanoBiotechnology, NanoGlycobiology unit, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Juliane C. Dohm
- Department of Biotechnology, Institute of Computational Biology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Heinz Himmelbauer
- Department of Biotechnology, Institute of Computational Biology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
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16
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Bloch S, Tomek MB, Friedrich V, Messner P, Schäffer C. Nonulosonic acids contribute to the pathogenicity of the oral bacterium Tannerella forsythia. Interface Focus 2019; 9:20180064. [PMID: 30842870 PMCID: PMC6388019 DOI: 10.1098/rsfs.2018.0064] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2018] [Indexed: 12/15/2022] Open
Abstract
Periodontitis is a polymicrobial, biofilm-caused, inflammatory disease affecting the tooth-supporting tissues. It is not only the leading cause of tooth loss worldwide, but can also impact systemic health. The development of effective treatment strategies is hampered by the complicated disease pathogenesis which is best described by a polymicrobial synergy and dysbiosis model. This model classifies the Gram-negative anaerobe Tannerella forsythia as a periodontal pathogen, making it a prime candidate for interference with the disease. Tannerella forsythia employs a protein O-glycosylation system that enables high-density display of nonulosonic acids via the bacterium's two-dimensional crystalline cell surface layer. Nonulosonic acids are sialic acid-like sugars which are well known for their pivotal biological roles. This review summarizes the current knowledge of T. forsythia's unique cell envelope with a focus on composition, biosynthesis and functional implications of the cell surface O-glycan. We have obtained evidence that glycobiology affects the bacterium's immunogenicity and capability to establish itself in the polymicrobial oral biofilm. Analysis of the genomes of different T. forsythia isolates revealed that complex protein O-glycosylation involving nonulosonic acids is a hallmark of pathogenic T. forsythia strains and, thus, constitutes a valuable target for the design of novel anti-infective strategies to combat periodontitis.
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