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Bacteroides thetaiotaomicron rough-type lipopolysaccharide: The chemical structure and the immunological activity. Carbohydr Polym 2022; 297:120040. [DOI: 10.1016/j.carbpol.2022.120040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/20/2022] [Accepted: 08/23/2022] [Indexed: 11/20/2022]
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2
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Chinthamani S, Settem RP, Honma K, Stafford GP, Sharma A. Tannerella forsythia strains differentially induce interferon gamma-induced protein 10 (IP-10) expression in macrophages due to lipopolysaccharide heterogeneity. Pathog Dis 2022; 80:6566341. [PMID: 35404415 PMCID: PMC9053306 DOI: 10.1093/femspd/ftac008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/18/2022] [Accepted: 04/07/2022] [Indexed: 11/12/2022] Open
Abstract
Abstract
Tannerella forsythia is strongly implicated in the development of periodontitis, an inflammatory disease that destroys the bone and soft tissues supporting the tooth. To date, the knowledge of the virulence attributes of T. forsythia species has mainly come from studies with a laboratory adapted strain (ATCC 43 037). In this study, we focused on two T. forsythia clinical isolates, UB4 and UB20, in relation to their ability to activate macrophages. We found that these clinical isolates differentially induced proinflammatory cytokine expression in macrophages. Prominently, the expression of the chemokine protein IP-10 (CXCL10) was highly induced by UB20 as compared to UB4 and the laboratory strain ATCC 43 037. Our study focused on the lipopolysaccharide component (LPS) of these strains and found that UB20 expressed a smooth-type LPS, unlike UB4 and ATCC 43 037 each of which expressed a rough-type LPS. The LPS from UB20, via activation of TLR4, was found to be a highly potent inducer of IP-10 expression via signaling through STAT1 (signal transducer and activator of transcription-1). These data suggest that pathogenicity of T. forsythia species could be strain dependent and the LPS heterogeneity associated with the clinical strains might be responsible for their pathogenic potential and severity of periodontitis.
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Affiliation(s)
| | | | | | | | - Ashu Sharma
- Oral Biology, University at Buffalo, Buffalo, NY, USA
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3
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Plazinski W, Roslund MU, Säwén E, Engström O, Tähtinen P, Widmalm G. Tautomers of N-acetyl-d-allosamine: an NMR and computational chemistry study. Org Biomol Chem 2021; 19:7190-7201. [PMID: 34382051 DOI: 10.1039/d1ob01139a] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
d-Allosamine is a rare sugar in Nature but its pyranoid form has been found α-linked in the core region of the lipopolysaccharide from the Gram-negative bacterium Porphyromonas gingivalis and in the chitanase inhibitor allosamidin, then β-linked and N-acetylated. In water solution the monosaccharide N-acetyl-d-allosamine (d-AllNAc) shows a significant presence of four tautomers arising from pyranoid and furanoid ring forms and anomeric configurations. The furanoid ring forms both showed 3JH1,H2≈ 4.85 Hz and to differentiate the anomeric configurations a series of chemical shift anisotropy/dipole-dipole cross-correlated relaxation NMR experiments was performed in which the α-anomeric form showed notable different relaxation rates for its components of the H1 doublet, thereby making it possible to elucidate the anomeric configuration of each of the furanoses. The conformational preferences of the different forms of d-AllNAc were investigated by 3JHH, 2JCH and 3JCH coupling constants from NMR experiments, molecular dynamics simulations and density functional theory calculations. The pyranose form resides in the 4C1 conformation and the furanose ring form has the majority of its conformers located on the South-East region of the pseudorotation wheel, with a small population in the Northern hemisphere. The tautomeric equilibrium was quite sensitive to changes in temperature, where the β-anomer of the pyranoid ring form decreased upon a temperature increase while the other forms increased.
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Affiliation(s)
- Wojciech Plazinski
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, 30-239 Krakow, Poland
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4
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Marcano R, Rojo MÁ, Cordoba-Diaz D, Garrosa M. Pathological and Therapeutic Approach to Endotoxin-Secreting Bacteria Involved in Periodontal Disease. Toxins (Basel) 2021; 13:533. [PMID: 34437404 PMCID: PMC8402370 DOI: 10.3390/toxins13080533] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 07/26/2021] [Indexed: 12/16/2022] Open
Abstract
It is widely recognized that periodontal disease is an inflammatory entity of infectious origin, in which the immune activation of the host leads to the destruction of the supporting tissues of the tooth. Periodontal pathogenic bacteria like Porphyromonas gingivalis, that belongs to the complex net of oral microflora, exhibits a toxicogenic potential by releasing endotoxins, which are the lipopolysaccharide component (LPS) available in the outer cell wall of Gram-negative bacteria. Endotoxins are released into the tissues causing damage after the cell is lysed. There are three well-defined regions in the LPS: one of them, the lipid A, has a lipidic nature, and the other two, the Core and the O-antigen, have a glycosidic nature, all of them with independent and synergistic functions. Lipid A is the "bioactive center" of LPS, responsible for its toxicity, and shows great variability along bacteria. In general, endotoxins have specific receptors at the cells, causing a wide immunoinflammatory response by inducing the release of pro-inflammatory cytokines and the production of matrix metalloproteinases. This response is not coordinated, favoring the dissemination of LPS through blood vessels, as well as binding mainly to Toll-like receptor 4 (TLR4) expressed in the host cells, leading to the destruction of the tissues and the detrimental effect in some systemic pathologies. Lipid A can also act as a TLRs antagonist eliciting immune deregulation. Although bacterial endotoxins have been extensively studied clinically and in a laboratory, their effects on the oral cavity and particularly on periodontium deserve special attention since they affect the connective tissue that supports the tooth, and can be linked to advanced medical conditions. This review addresses the distribution of endotoxins associated with periodontal pathogenic bacteria and its relationship with systemic diseases, as well as the effect of some therapeutic alternatives.
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Affiliation(s)
- Rosalia Marcano
- Department of Cell Biology, Histology and Pharmacology, Faculty of Medicine and INCYL, University of Valladolid, 47005 Valladolid, Spain;
| | - M. Ángeles Rojo
- Area of Experimental Sciences, Miguel de Cervantes European University, 47012 Valladolid, Spain;
| | - Damián Cordoba-Diaz
- Area of Pharmaceutics and Food Technology, Faculty of Pharmacy, and IUFI, Complutense University of Madrid, 28040 Madrid, Spain;
| | - Manuel Garrosa
- Department of Cell Biology, Histology and Pharmacology, Faculty of Medicine and INCYL, University of Valladolid, 47005 Valladolid, Spain;
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5
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Avila-Calderón ED, Ruiz-Palma MDS, Aguilera-Arreola MG, Velázquez-Guadarrama N, Ruiz EA, Gomez-Lunar Z, Witonsky S, Contreras-Rodríguez A. Outer Membrane Vesicles of Gram-Negative Bacteria: An Outlook on Biogenesis. Front Microbiol 2021; 12:557902. [PMID: 33746909 PMCID: PMC7969528 DOI: 10.3389/fmicb.2021.557902] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 02/04/2021] [Indexed: 12/14/2022] Open
Abstract
Outer membrane vesicles (OMVs) from Gram-negative bacteria were first described more than 50 years ago. However, the molecular mechanisms involved in biogenesis began to be studied only in the last few decades. Presently, the biogenesis and molecular mechanisms for their release are not completely known. This review covers the most recent information on cellular components involved in OMV biogenesis, such as lipoproteins and outer membrane proteins, lipopolysaccharide, phospholipids, quorum-sensing molecules, and flagella.
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Affiliation(s)
- Eric Daniel Avila-Calderón
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico.,Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados, Instituto Politécnico Nacional, CINVESTAV-IPN, México City, Mexico
| | - María Del Socorro Ruiz-Palma
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico.,División Químico Biológicas, Universidad Tecnológica de Tecámac, Tecámac, Mexico
| | - Ma Guadalupe Aguilera-Arreola
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
| | - Norma Velázquez-Guadarrama
- Unidad de Investigación en enfermedades infecciosas, Hospital Infantil de México Federico Gómez, Ciudad de México, Mexico
| | - Enrico A Ruiz
- Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
| | - Zulema Gomez-Lunar
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
| | - Sharon Witonsky
- Center for One Health Research, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States.,Large Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States
| | - Araceli Contreras-Rodríguez
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico
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6
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PorZ, an Essential Component of the Type IX Secretion System of Porphyromonas gingivalis, Delivers Anionic Lipopolysaccharide to the PorU Sortase for Transpeptidase Processing of T9SS Cargo Proteins. mBio 2021; 12:mBio.02262-20. [PMID: 33622730 PMCID: PMC8545088 DOI: 10.1128/mbio.02262-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cargo proteins of the type IX secretion system (T9SS) in human pathogens from the Bacteroidetes phylum invariably possess a conserved C-terminal domain (CTD) that functions as a signal for outer membrane (OM) translocation. In Porphyromonas gingivalis, the CTD of cargos is cleaved off after translocation, and anionic lipopolysaccharide (A-LPS) is attached. This transpeptidase reaction anchors secreted proteins to the OM. PorZ, a cell surface-associated protein, is an essential component of the T9SS whose function was previously unknown. We recently solved the crystal structure of PorZ and found that it consists of two β-propeller moieties, followed by a CTD. In this study, we performed structure-based modeling, suggesting that PorZ is a carbohydrate-binding protein. Indeed, we found that recombinant PorZ specifically binds A-LPS in vitro Binding was blocked by monoclonal antibodies that specifically react with a phosphorylated branched mannan in the anionic polysaccharide (A-PS) component of A-LPS, but not with the core oligosaccharide or the lipid A endotoxin. Examination of A-LPS derived from a cohort of mutants producing various truncations of A-PS confirmed that the phosphorylated branched mannan is indeed the PorZ ligand. Moreover, purified recombinant PorZ interacted with the PorU sortase in an A-LPS-dependent manner. This interaction on the cell surface is crucial for the function of the "attachment complex" composed of PorU, PorZ, and the integral OM β-barrel proteins PorV and PorQ, which is involved in posttranslational modification and retention of T9SS cargos on the bacterial surface.IMPORTANCE Bacteria have evolved multiple systems to transport effector proteins to their surface or into the surrounding milieu. These proteins have a wide range of functions, including attachment, motility, nutrient acquisition, and toxicity in the host. Porphyromonas gingivalis, the human pathogen responsible for severe gum diseases (periodontitis), uses a recently characterized type IX secretion system (T9SS) to translocate and anchor secreted virulence effectors to the cell surface. Anchorage is facilitated by sortase, an enzyme that covalently attaches T9SS cargo proteins to a unique anionic lipopolysaccharide (A-LPS) moiety of P. gingivalis Here, we show that the T9SS component PorZ interacts with sortase and specifically binds A-LPS. Binding is mediated by a phosphorylated branched mannan repeat in A-LPS polysaccharide. A-LPS-bound PorZ interacts with sortase with significantly higher affinity, facilitating modification of cargo proteins by the cell surface attachment complex of the T9SS.
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7
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Dai L, Barrett L, Plaisance-Bonstaff K, Post SR, Qin Z. Porphyromonas gingivalis coinfects with KSHV in oral cavities of HIV+ patients and induces viral lytic reactivation. J Med Virol 2020; 92:3862-3867. [PMID: 32436999 PMCID: PMC7679274 DOI: 10.1002/jmv.26028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 11/06/2022]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) infection causes several human cancers, including Kaposi's sarcoma (KS), one of the most common AIDS-associated tumors. The involvement of the oral cavity represents one common clinical manifestation of AIDS-KS individuals with periodontal diseases and an oral carriage of a variety of pathogenic bacteria, including Porphyromonas gingivalis. In the current study, we report the clinical relevance of P. gingivalis and KSHV coinfection in the oral cavity of a cohort of HIV+ patients. Furthermore, we found that P. gingivalis conditioned medium or derived lipopolysaccharide effectively induced KSHV lytic reactivation from infected oral cells. This reactivation requires TLR4 as well as the activities of p38 and Jun N-terminal kinase- mitogen-activated protein kinase signaling pathways. Our findings reveal the mechanisms through which coinfected periodontal pathogens potentially promote oncogenic virus pathogenesis in the unique niche of immunocompromised patients.
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Affiliation(s)
- Lu Dai
- Department of Pathology, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, 4301 W Markham St, Little Rock, AR 72205, USA
| | - Lindsey Barrett
- Department of Pathology, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, 4301 W Markham St, Little Rock, AR 72205, USA
| | - Karlie Plaisance-Bonstaff
- Departments of Medicine, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center, 1700 Tulane Ave., New Orleans, LA 70112, USA
| | - Steven R. Post
- Department of Pathology, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, 4301 W Markham St, Little Rock, AR 72205, USA
| | - Zhiqiang Qin
- Department of Pathology, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, 4301 W Markham St, Little Rock, AR 72205, USA
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8
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Type IX Secretion System Cargo Proteins Are Glycosylated at the C Terminus with a Novel Linking Sugar of the Wbp/Vim Pathway. mBio 2020; 11:mBio.01497-20. [PMID: 32873758 PMCID: PMC7468200 DOI: 10.1128/mbio.01497-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Porphyromonas gingivalis and Tannerella forsythia, two pathogens associated with severe gum disease, use the type IX secretion system (T9SS) to secrete and attach toxic arrays of virulence factor proteins to their cell surfaces. The proteins are tethered to the outer membrane via glycolipid anchors that have remained unidentified for more than 2 decades. In this study, the first sugar molecules (linking sugars) in these anchors are identified and found to be novel compounds. The novel biosynthetic pathway of these linking sugars is also elucidated. A diverse range of bacteria that do not have the T9SS were found to have the genes for this pathway, suggesting that they may synthesize similar linking sugars for utilization in different systems. Since the cell surface attachment of virulence factors is essential for virulence, these findings reveal new targets for the development of novel therapies. Porphyromonas gingivalis and Tannerella forsythia use the type IX secretion system to secrete cargo proteins to the cell surface where they are anchored via glycolipids. In P. gingivalis, the glycolipid is anionic lipopolysaccharide (A-LPS), of partially known structure. Modified cargo proteins were deglycosylated using trifluoromethanesulfonic acid and digested with trypsin or proteinase K. The residual modifications were then extensively analyzed by tandem mass spectrometry. The C terminus of each cargo protein was amide-bonded to a linking sugar whose structure was deduced to be 2-N-seryl, 3-N-acetylglucuronamide in P. gingivalis and 2-N-glycyl, 3-N-acetylmannuronic acid in T. forsythia. The structures indicated the involvement of the Wbp pathway to produce 2,3-di-N-acetylglucuronic acid and a WbpS amidotransferase to produce the uronamide form of this sugar in P. gingivalis. The wbpS gene was identified as PGN_1234 as its deletion resulted in the inability to produce the uronamide. In addition, the P. gingivalisvimA mutant which lacks A-LPS was successfully complemented by the T. forsythiavimA gene; however, the linking sugar was altered to include glycine rather than serine. After removal of the acetyl group at C-2 by the putative deacetylase, VimE, VimA presumably transfers the amino acid to complete the biosynthesis. The data explain all the enzyme activities required for the biosynthesis of the linking sugar accounting for six A-LPS-specific genes. The linking sugar is therefore the key compound that enables the attachment of cargo proteins in P. gingivalis and T. forsythia. We propose to designate this novel linking sugar biosynthetic pathway the Wbp/Vim pathway.
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Activation of ASC Inflammasome Driven by Toll-Like Receptor 4 Contributes to Host Immunity against Rickettsial Infection. Infect Immun 2020; 88:IAI.00886-19. [PMID: 32014896 DOI: 10.1128/iai.00886-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 01/23/2020] [Indexed: 02/07/2023] Open
Abstract
Rickettsiae are cytosolically replicating, obligately intracellular bacteria causing human infections worldwide with potentially fatal outcomes. We previously showed that Rickettsia australis activates ASC inflammasome in macrophages. In the present study, host susceptibility of ASC inflammasome-deficient mice to R. australis was significantly greater than that of C57BL/6 (B6) controls and was accompanied by increased rickettsial loads in various organs. Impaired host control of R. australis in vivo in ASC-/- mice was associated with dramatically reduced levels of interleukin 1β (IL-1β), IL-18, and gamma interferon (IFN-γ) in sera. The intracellular concentrations of R. australis in bone marrow-derived macrophages (BMMs) of TLR4-/- and ASC-/- mice were significantly greater than those in BMMs of B6 controls, highlighting the important role of inflammasome and these molecules in controlling rickettsiae in macrophages. Compared to B6 BMMs, TLR4-/- BMMs failed to secrete a significant level of IL-1β and had reduced expression levels of pro-IL-1β in response to infection with R. australis, suggesting that rickettsiae activate ASC inflammasome via a Toll-like receptor 4 (TLR4)-dependent mechanism. Further mechanistic studies suggest that the lipopolysaccharide (LPS) purified from R. australis together with ATP stimulation led to cleavage of pro-caspase-1 and pro-IL-1β, resulting in TLR4-dependent secretion of IL-1β. Taken together, these observations indicate that activation of ASC inflammasome, most likely driven by interaction of TLR4 with rickettsial LPS, contributes to host protective immunity against R. australis These findings provide key insights into defining the interactions of rickettsiae with the host innate immune system.
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Chatterjee D, Nayak S, Paul A, Yadav S. Syntheses of Orthogonally Protected
d‐
Galactosamine,
d
‐Allosamine and
d
‐Gulosamine Thioglycoside Building Blocks with
N
‐phthalimido Groups. ASIAN J ORG CHEM 2019. [DOI: 10.1002/ajoc.201900397] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Debnath Chatterjee
- Department of ChemistryIndian Institute of Technology (ISM) Dhanbad 826004, Jharkhand India
| | - Sourav Nayak
- Department of ChemistryIndian Institute of Technology (ISM) Dhanbad 826004, Jharkhand India
| | - Abhijit Paul
- Department of ChemistryIndian Institute of Technology (ISM) Dhanbad 826004, Jharkhand India
| | - Somnath Yadav
- Department of ChemistryIndian Institute of Technology (ISM) Dhanbad 826004, Jharkhand India
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Immunological Pathways Triggered by Porphyromonas gingivalis and Fusobacterium nucleatum: Therapeutic Possibilities? Mediators Inflamm 2019; 2019:7241312. [PMID: 31341421 PMCID: PMC6612971 DOI: 10.1155/2019/7241312] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/28/2019] [Accepted: 05/19/2019] [Indexed: 02/06/2023] Open
Abstract
Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum) are Gram-negative anaerobic bacteria possessing several virulence factors that make them potential pathogens associated with periodontal disease. Periodontal diseases are chronic inflammatory diseases of the oral cavity, including gingivitis and periodontitis. Periodontitis can lead to tooth loss and is considered one of the most prevalent diseases worldwide. P. gingivalis and F. nucleatum possess virulence factors that allow them to survive in hostile environments by selectively modulating the host's immune-inflammatory response, thereby creating major challenges to host cell survival. Studies have demonstrated that bacterial infection and the host immune responses are involved in the induction of periodontitis. The NLRP3 inflammasome and its effector molecules (IL-1β and caspase-1) play roles in the development of periodontitis. We and others have reported that the purinergic P2X7 receptor plays a role in the modulation of periodontal disease and intracellular pathogen control. Caspase-4/5 (in humans) and caspase-11 (in mice) are important effectors for combating bacterial pathogens via mediation of cell death and IL-1β release. The exact molecular events of the host's response to these bacteria are not fully understood. Here, we review innate and adaptive immune responses induced by P. gingivalis and F. nucleatum infections and discuss the possibility of manipulations of the immune response as therapeutic strategies. Given the global burden of periodontitis, it is important to develop therapeutic targets for the prophylaxis of periodontopathogen infections.
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Naito M, Tominaga T, Shoji M, Nakayama K. PGN_0297 is an essential component of the type IX secretion system (T9SS) in Porphyromonas gingivalis: Tn-seq analysis for exhaustive identification of T9SS-related genes. Microbiol Immunol 2019; 63:11-20. [PMID: 30599082 PMCID: PMC6590471 DOI: 10.1111/1348-0421.12665] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Revised: 11/28/2018] [Accepted: 12/20/2018] [Indexed: 12/22/2022]
Abstract
The type IX secretion system (T9SS) was originally discovered in Porphyromonas gingivalis, one of the pathogenic bacteria associated with periodontal disease and is now known to be present in many members of the phylum Bacteroidetes. The T9SS secretes a number of potent virulence factors, including the highly hydrolytic proteases called gingipains, across the outer membrane in P. gingivalis. To understand the entire machinery of T9SS, an exhaustive search for T9SS‐related genes in P. gingivalis using the mariner family transposon (Tn) and Tn‐seq analysis was performed. Seven hundred and two Tn insertion sites in Tn mutants with no colony pigmentation that is associated with Lys‐gingipain (Kgp) defectiveness were determined, and it was found that the Tn was inserted in the kgp gene and 54 T9SS‐related candidate genes. Thirty‐three out of the 54 genes were already known as T9SS‐related genes. Furthermore, deletion mutant analysis of the remaining 21 genes revealed that they were not related to the T9SS. The 33 T9SS‐related genes include a gene for PGN_0297, which was found to be associated with the T9SS components PorK and PorN. A PGN_0297 gene deletion mutant was constructed, and it was found that the mutant showed no colony pigmentation, hemagglutination or gingipain activities, indicating that PGN_0297 was an essential component of the T9SS. The 33 genes did not include the six genes (gppX, omp17, porY, rfa, sigP and wzx) that were also reported as T9SS‐related genes. gppX deletion and insertion mutants were constructed, and it was found that they did not show deficiency in the T9SS.
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Affiliation(s)
- Mariko Naito
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1 Sakamoto, Nagasaki City, Nagasaki, 852-8588, Japan
| | - Takashi Tominaga
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1 Sakamoto, Nagasaki City, Nagasaki, 852-8588, Japan
| | - Mikio Shoji
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1 Sakamoto, Nagasaki City, Nagasaki, 852-8588, Japan
| | - Koji Nakayama
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1 Sakamoto, Nagasaki City, Nagasaki, 852-8588, Japan
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13
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Pandya UM, Egbuta C, Abdullah Norman TM, Chiang CYE, Wiersma VR, Panchal RG, Bremer E, Eggleton P, Gold LI. The Biophysical Interaction of the Danger-Associated Molecular Pattern (DAMP) Calreticulin with the Pattern-Associated Molecular Pattern (PAMP) Lipopolysaccharide. Int J Mol Sci 2019; 20:ijms20020408. [PMID: 30669362 PMCID: PMC6359024 DOI: 10.3390/ijms20020408] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 01/11/2019] [Accepted: 01/12/2019] [Indexed: 12/15/2022] Open
Abstract
The endoplasmic reticulum (ER) chaperone protein, calreticulin (CRT), is essential for proper glycoprotein folding and maintaining cellular calcium homeostasis. During ER stress, CRT is overexpressed as part of the unfolded protein response (UPR). In addition, CRT can be released as a damage-associated molecular pattern (DAMP) molecule that may interact with pathogen-associated molecular patterns (PAMPs) during the innate immune response. One such PAMP is lipopolysaccharide (LPS), a component of the gram-negative bacterial cell wall. In this report, we show that recombinant and native human placental CRT strongly interacts with LPS in solution, solid phase, and the surface of gram-negative and gram-positive bacteria. Furthermore, LPS induces oilgomerization of CRT with a disappearance of the monomeric form. The application of recombinant CRT (rCRT) to size exclusion and anion exchange chromatography shows an atypical heterogeneous elution profile, indicating that LPS affects the conformation and ionic charge of CRT. Interestingly, LPS bound to CRT is detected in sera of bronchiectasis patients with chronic bacterial infections. By ELISA, rCRT dose-dependently bound to solid phase LPS via the N- and C-domain globular head region of CRT and the C-domain alone. The specific interaction of CRT with LPS may be important in PAMP innate immunity.
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Affiliation(s)
- Unnati M Pandya
- New York University School of Medicine--Langone Health, Departments of Medicine and Pathology, Division of Translational Medicine, 550 First Ave, New York, NY 10016, USA.
| | - Chinaza Egbuta
- New York University School of Medicine--Langone Health, Departments of Medicine and Pathology, Division of Translational Medicine, 550 First Ave, New York, NY 10016, USA.
| | | | - Chih-Yuan Edward Chiang
- Target Discovery and Experimental Microbiology Department, Molecular and Translational Sciences Division, US Army Research Institute of Infectious Diseases, Frederick, MD 21702, USA.
| | - Valerie R Wiersma
- Department of Hematology, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, The Netherlands.
| | - Rekha G Panchal
- Target Discovery and Experimental Microbiology Department, Molecular and Translational Sciences Division, US Army Research Institute of Infectious Diseases, Frederick, MD 21702, USA.
| | - Edwin Bremer
- Department of Hematology, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, The Netherlands.
| | - Paul Eggleton
- University of Exeter Medical School, Exeter EX1 2LU, Devon UK.
- UCB Pharma, Slough SL1 3WE, UK.
| | - Leslie I Gold
- New York University School of Medicine--Langone Health, Departments of Medicine and Pathology, Division of Translational Medicine, 550 First Ave, New York, NY 10016, USA.
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14
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Wu L, Zhao L, Wang J, Liu C, Li Y, Wu Y. pckA-deficient Porphyromonas gingivalis W83 shows reduction in hemagglutination activity and alteration in the distribution of gingipain activity. Eur J Oral Sci 2018; 126:359-366. [PMID: 30126013 DOI: 10.1111/eos.12565] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2018] [Indexed: 02/05/2023]
Abstract
Bacterial metabolism during infection is related to bacterial persistence and virulence factors. Porphyromonas gingivalis is a key pathogen that contributes to chronic periodontitis. Our previous study showed that pckA, the gene encoding phosphoenolpyruvate carboxykinase, is a putative-specific pathogenic gene of virulent strains of P. gingivalis. Here, a pckA-deficient strain (ΔPG1676) was constructed in P. gingivalis W83. Virulence properties were compared between the mutant and wild-type strains. Specifically, hemagglutination activity was determined by the ability to agglutinate sheep erythrocytes. Gingipain activity was detected using synthetic-specific substrates. Gene expression levels were analyzed using RT-qPCR, and cell surface-associated polysaccharides were examined by silver staining and electron microscopy. Inactivation of the pckA gene did not affect bacterial growth and lipopolysaccharide formation but led to a reduction in hemagglutination activity and downregulation in expression of the hemagglutination-associated gene, rfa, when compared with the wild-type strain. Additionally, the ΔPG1676 mutant exhibited an alteration in the distribution of gingipain activity. Increased gingipain activity was detected on the cell surface, but a decrease in its activity in the culture supernatant was shown. Taken together, our results suggest that the pckA gene plays a role in modulating the virulence of P. gingivalis W83.
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Affiliation(s)
- Leng Wu
- Department of Periodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Lei Zhao
- Department of Periodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jun Wang
- Department of Periodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Chengcheng Liu
- Department of Periodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yan Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yafei Wu
- Department of Periodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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15
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Galectin-3 Plays an Important Role in Preterm Birth Caused by Dental Infection of Porphyromonas gingivalis. Sci Rep 2018; 8:2867. [PMID: 29434245 PMCID: PMC5809409 DOI: 10.1038/s41598-018-21072-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 01/25/2018] [Indexed: 11/17/2022] Open
Abstract
Dental infection is risk for preterm birth (PTB) through unclear mechanisms. We established a dental infection-induced PTB mouse model, in which Porphyromonas gingivalis (P.g.) induced PTB by 2 days. We analysed pathogenic factors contributing to PTB and their effects on trophoblasts in vitro. TNF-α, IL-8, and COX-2 were upregulated in P.g.-infected placenta. Galectin-3 (Gal-3), an immune regulator, was significantly upregulated in placenta, amniotic fluid, and serum. In vitro, P.g.-lipopolysaccharide (P.g.-LPS) increased TNF-α and Gal-3 in trophoblasts via NF-κB/MAPK signalling. Gal-3 inhibition significantly downregulated P.g.-LPS-induced TNF-α production. TNF-α upregulated Gal-3. Gal-3 also increased cytokines and Gal-3 through NF-κB/MAPK signalling. Moreover, Gal-3 suppressed CD-66a expression at the maternal-foetal interface. Co-stimulation with Gal-3 and P.g.-LPS upregulated cytokine levels, while Gal-3 plus Aggregatibacter actinomycetemcomitans (A.a.)- or Escherichia coli (E. coli)-LPS treatment downregulated them, indicating the critical role of Gal-3 especially in P.g. dental infection-induced PTB. P.g.-dental infection induced PTB, which was associated with Gal-3-dependent cytokine production. New therapies and/or diagnostic systems targeting Gal-3 may reduce PTB.
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16
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Shoji M, Sato K, Yukitake H, Kamaguchi A, Sasaki Y, Naito M, Nakayama K. Identification of genes encoding glycosyltransferases involved in lipopolysaccharide synthesis inPorphyromonas gingivalis. Mol Oral Microbiol 2017; 33:68-80. [DOI: 10.1111/omi.12200] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2017] [Indexed: 12/16/2022]
Affiliation(s)
- M. Shoji
- Department of Microbiology and Oral Infection; Nagasaki University Graduate School of Biomedical Sciences; Nagasaki Japan
| | - K. Sato
- Department of Microbiology and Oral Infection; Nagasaki University Graduate School of Biomedical Sciences; Nagasaki Japan
| | - H. Yukitake
- Department of Microbiology and Oral Infection; Nagasaki University Graduate School of Biomedical Sciences; Nagasaki Japan
| | - A. Kamaguchi
- Department of Oral Microbiology; School of Dentistry; Health Sciences University of Hokkaido; Hokkaido Japan
| | - Y. Sasaki
- Department of Microbiology and Oral Infection; Nagasaki University Graduate School of Biomedical Sciences; Nagasaki Japan
| | - M. Naito
- Department of Microbiology and Oral Infection; Nagasaki University Graduate School of Biomedical Sciences; Nagasaki Japan
| | - K. Nakayama
- Department of Microbiology and Oral Infection; Nagasaki University Graduate School of Biomedical Sciences; Nagasaki Japan
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17
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Rangarajan M, Aduse‐Opoku J, Paramonov N, Hashim A, Curtis M. Hemin binding by Porphyromonas gingivalis strains is dependent on the presence of A-LPS. Mol Oral Microbiol 2017; 32:365-374. [PMID: 28107612 PMCID: PMC5600137 DOI: 10.1111/omi.12178] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2017] [Indexed: 11/29/2022]
Abstract
Porphyromonas gingivalis is a Gram-negative black pigmenting anaerobe that is unable to synthesize heme [Fe(II)-protoporphyrin IX] or hemin [Fe(III)-protoporphyrin IX-Cl], which are important growth/virulence factors, and must therefore derive them from the host. Porphyromonas gingivalis expresses several proteinaceous hemin-binding sites, which are important in the binding/transport of heme/hemin from the host. It also synthesizes several virulence factors, namely cysteine-proteases Arg- and Lys-gingipains and two lipopolysaccharides (LPS), O-LPS and A-LPS. The gingipains are required for the production of the black pigment, μ-oxo-bisheme {[Fe(III)PPIX]2 O}, which is derived from hemoglobin and deposited on the bacterial cell-surface leading to the characteristic black colonies when grown on blood agar. In this study we investigated the role of LPS in the deposition of μ-oxo-bisheme on the cell-surface. A P. gingivalis mutant defective in the biosynthesis of Arg-gingipains, namely rgpA/rgpB, produces brown colonies on blood agar and mutants defective in Lys-gingipain (kgp) and LPS biosynthesis namely porR, waaL, wzy, and pg0129 (α-1, 3-mannosyltransferase) produce non-pigmented colonies. However, only those mutants lacking A-LPS showed reduced hemin-binding when cells in suspension were incubated with hemin. Using native, de-O-phosphorylated and de-lipidated LPS from P. gingivalis W50 and porR strains, we demonstrated that hemin-binding to O-polysaccharide (PS) and to the lipid A moiety of LPS was reduced compared with hemin-binding to A-PS. We conclude that A-LPS in the outer-membrane of P. gingivalis serves as a scaffold/anchor for the retention of μ-oxo-bisheme on the cell surface and pigmentation is dependent on the presence of A-LPS.
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Affiliation(s)
- M. Rangarajan
- Institute of DentistryBarts and The London School of Medicine & DentistryQueen Mary University of LondonLondonUK
| | - J. Aduse‐Opoku
- Institute of DentistryBarts and The London School of Medicine & DentistryQueen Mary University of LondonLondonUK
| | - N.A. Paramonov
- Institute of DentistryBarts and The London School of Medicine & DentistryQueen Mary University of LondonLondonUK
| | - A. Hashim
- Institute of DentistryBarts and The London School of Medicine & DentistryQueen Mary University of LondonLondonUK
- College of DentistryKing Faisal UniversityAl‐AhsaSaudi Arabia
| | - M.A. Curtis
- Institute of DentistryBarts and The London School of Medicine & DentistryQueen Mary University of LondonLondonUK
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18
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Veith PD, Glew MD, Gorasia DG, Reynolds EC. Type IX secretion: the generation of bacterial cell surface coatings involved in virulence, gliding motility and the degradation of complex biopolymers. Mol Microbiol 2017; 106:35-53. [DOI: 10.1111/mmi.13752] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/14/2017] [Indexed: 12/15/2022]
Affiliation(s)
- Paul D. Veith
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute; The University of Melbourne; Melbourne Australia
| | - Michelle D. Glew
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute; The University of Melbourne; Melbourne Australia
| | - Dhana G. Gorasia
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute; The University of Melbourne; Melbourne Australia
| | - Eric C. Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute; The University of Melbourne; Melbourne Australia
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19
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Using Tn-seq To Identify Pigmentation-Related Genes of Porphyromonas gingivalis: Characterization of the Role of a Putative Glycosyltransferase. J Bacteriol 2017; 199:JB.00832-16. [PMID: 28484050 DOI: 10.1128/jb.00832-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 05/04/2017] [Indexed: 11/20/2022] Open
Abstract
Cellular pigmentation is an important virulence factor of the oral pathogen Porphyromonas gingivalis Pigmentation has been associated with many bacterial functions, including but not limited to colonization, maintaining a local anaerobic environment by binding oxygen molecules, and defense against reactive oxygen species (ROS) produced by immune cells. Pigmentation-associated loci identified to date have involved lipopolysaccharide, fimbriae, and heme acquisition and processing. We utilized a transposon mutant library of P. gingivalis strain ATCC 33277 and screened for pigmentation-defective colonies using massively parallel sequencing of the transposon junctions (Tn-seq) to identify genes involved in pigmentation. Transposon insertions at 235 separate sites, located in 67 genes and 15 intergenic regions, resulted in altered pigmentation: 7 of the genes had previously been shown to be involved in pigmentation, while 75 genes and intergenic regions had not. To further confirm identification, we generated a smaller transposon mutant library in P. gingivalis strain W83 and identified pigment mutations in several of the same loci as those identified in the screen in ATCC 33277 but also eight that were not identified in the ATCC 33277 screen. PGN_0361/PG_0264, a putative glycosyltransferase gene located between two tRNA synthetase genes and adjacent to a miniature inverted-repeat transposable element, was identified in the Tn-seq screen and then verified through targeted deletion and complementation. Deletion mutations in PGN_0361/PG_0264 glycosyltransferase abolish pigmentation, modulate gingipain protease activity, and alter lipopolysaccharide. The mechanisms of involvement in pigmentation for other loci identified in this study remain to be determined, but our screen provides the most complete survey of genes involved in pigmentation to date.IMPORTANCEP. gingivalis has been implicated in the onset and progression of periodontal disease. One important virulence factor is the bacterium's ability to produce pigment. Using a transposon library, we were able to identify both known and novel genes involved in pigmentation of P. gingivalis We identified a glycosyltransferase, previously not associated with pigmentation, that is required for pigmentation and determined its mechanism of involvement. A better understanding of the genes involved in pigmentation may lead to new insights into the complex mechanisms involved in this important virulence characteristic and could facilitate development of novel therapeutics.
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20
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Liu C, Miller DP, Wang Y, Merchant M, Lamont RJ. Structure-function aspects of the Porphyromonas gingivalis tyrosine kinase Ptk1. Mol Oral Microbiol 2016; 32:314-323. [PMID: 27498608 DOI: 10.1111/omi.12173] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2016] [Indexed: 02/05/2023]
Abstract
The development of synergistically pathogenic communities of Porphyromonas gingivalis and Streptococcus gordonii is controlled by a tyrosine-phosphorylation-dependent signaling pathway in P. gingivalis. The Ptk1 bacterial tyrosine (BY) kinase of P. gingivalis is required for maximal community development and for the production of extracellular polysaccharide. We show that the consensus BY kinase Walker A and B domains, the RK cluster, and the YC domain of Ptk1 are necessary for autophosphorylation and for substrate phosphorylation. Mass spectrometry showed that six tyrosine residues in a 16-amino-acid C-terminal region were phosphorylated in recombinant (r) Ptk1. Complementation of a ptk1 mutant with the wild-type ptk1 allele in trans restored community development between P. gingivalis and S. gordonii, and extracellular polysaccharide production by P. gingivalis. In contrast, complementation of Δptk1 with ptk1 containing a mutation in the Walker A domain failed to restore community development or extracellular polysaccharide production. rPtk1 was capable of phosphorylating the tyrosine phosphatase Ltp1 and the transcriptional regulator CdhR, both of which are involved in the development of P. gingivalis communities with S. gordonii.
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Affiliation(s)
- C Liu
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY, USA.,State Key Laboratory of Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - D P Miller
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY, USA
| | - Y Wang
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY, USA.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - M Merchant
- Department of Medicine, School of Medicine, University of Louisville, Louisville, KY, USA
| | - R J Lamont
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY, USA
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21
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Shoji M, Nakayama K. Glycobiology of the oral pathogen Porphyromonas gingivalis and related species. Microb Pathog 2015; 94:35-41. [PMID: 26456570 DOI: 10.1016/j.micpath.2015.09.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 09/29/2015] [Accepted: 09/30/2015] [Indexed: 10/22/2022]
Abstract
Until recently, glycoproteins had only been described in eukaryotes. However, advances in detection methods and genome analyses have allowed the discovery of N-linked or O-linked glycoproteins, similar to those found in eukaryotes, in some bacterial species. These prokaryotic glycoproteins play roles in adhesion, solubility, formation of protein complexes, protection from protein degradation, and changes in antigenicity. Periodontal pathogen Porphyromonas gingivalis secretes virulence proteins via the type IX secretion system, some of which localize on the cell surface by binding to lipopolysaccharide (LPS). These virulence proteins have a conserved C-terminal domain (CTD) region, which is used as a secretion signal. However, it is still uncertain how the secreted proteins on the cell surface bind to LPS. In this review, we discuss the synthesis of P. gingivalis O polysaccharide, which plays a role in anchoring the CTD protein on the cell surface, and recent discoveries of glycoproteins in P. gingivalis as well as other species in the phylum Bacteroidetes.
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Affiliation(s)
- Mikio Shoji
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
| | - Koji Nakayama
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan.
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22
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Porphyromonas gingivalis Type IX Secretion Substrates Are Cleaved and Modified by a Sortase-Like Mechanism. PLoS Pathog 2015; 11:e1005152. [PMID: 26340749 PMCID: PMC4560394 DOI: 10.1371/journal.ppat.1005152] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 08/14/2015] [Indexed: 12/11/2022] Open
Abstract
The type IX secretion system (T9SS) of Porphyromonas gingivalis secretes proteins possessing a conserved C-terminal domain (CTD) to the cell surface. The C-terminal signal is essential for these proteins to translocate across the outer membrane via the T9SS. On the surface the CTD of these proteins is cleaved prior to extensive glycosylation. It is believed that the modification on these CTD proteins is anionic lipopolysaccharide (A-LPS), which enables the attachment of CTD proteins to the cell surface. However, the exact site of modification and the mechanism of attachment of CTD proteins to the cell surface are unknown. In this study we characterized two wbaP (PG1964) mutants that did not synthesise A-LPS and accumulated CTD proteins in the clarified culture fluid (CCF). The CTDs of the CTD proteins in the CCF were cleaved suggesting normal secretion, however, the CTD proteins were not glycosylated. Mass spectrometric analysis of CTD proteins purified from the CCF of the wbaP mutants revealed the presence of various peptide/amino acid modifications from the growth medium at the C-terminus of the mature CTD proteins. This suggested that modification occurs at the C-terminus of T9SS substrates in the wild type P. gingivalis. This was confirmed by analysis of CTD proteins from wild type, where a 648 Da linker was identified to be attached at the C-terminus of mature CTD proteins. Importantly, treatment with proteinase K released the 648 Da linker from the CTD proteins demonstrating a peptide bond between the C-terminus and the modification. Together, this is suggestive of a mechanism similar to sortase A for the cleavage and modification/attachment of CTD proteins in P. gingivalis. PG0026 has been recognized as the CTD signal peptidase and is now proposed to be the sortase-like protein in P. gingivalis. To our knowledge, this is the first biochemical evidence suggesting a sortase-like mechanism in Gram-negative bacteria. Chronic periodontitis, associated with the pathogen Porphyromonas gingivalis, is a major public health problem. P. gingivalis secretes virulence factors including the gingipains via the type IX secretion system (T9SS). These proteins contain a C-terminal signal that allows their secretion through the T9SS and it is cleaved by the protein PG0026 at the cell surface. Here we identify a mechanism by which gingipains and other proteins attach to the cell surface of this bacterium. We found that after removal of the C-terminal signal, the proteins were modified via a peptide linkage to either a putative component of anionic lipopolysaccharide (A-LPS) in the wild type or peptides from the growth medium in mutants lacking A-LPS, which has been suggested to anchor the proteins to the cell surface. Results from this study provide evidence for the exact site of modification of these proteins with A-LPS. Furthermore, our results also demonstrate for the first time that the anchoring mechanism of this secretion system involves a substitution between the signal and the anchor (A-LPS) which can be explained by the action of a single enzyme known as a sortase, which we believe is PG0026. This is the first evidence for a sortase-like mechanism in Gram-negative bacteria.
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23
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Identification of the linkage between A-polysaccharide and the core in the A-lipopolysaccharide of Porphyromonas gingivalis W50. J Bacteriol 2015; 197:1735-46. [PMID: 25733619 DOI: 10.1128/jb.02562-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 02/24/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Porphyromonas gingivalis synthesizes two lipopolysaccharides (LPSs), O-LPS and A-LPS. The structure of the core oligosaccharide (OS) of O-LPS and the attachment site of the O-polysaccharide (O-PS) repeating unit [ → 3)-α-D-Galp-(1 → 6)-α-D-Glcp-(1 → 4)-α-L-Rhap-(1 → 3)-β-D-GalNAcp-(1 → ] to the core have been elucidated using the ΔPG1051 (WaaL, O-antigen ligase) and ΔPG1142 (Wzy, O-antigen polymerase) mutant strains, respectively. The core OS occurs as an "uncapped" glycoform devoid of O-PS and a "capped" glycoform that contains the attachment site of O-PS via β-d-GalNAc at position O-3 of the terminal α-(1 → 3)-linked mannose (Man) residue. In this study, the attachment site of A-PS to the core OS was determined based on structural analysis of SR-type LPS (O-LPS and A-LPS) isolated from a P. gingivalis ΔPG1142 mutant strain by extraction with aqueous hot phenol to minimize the destruction of A-LPS. Application of one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy in combination with methylation analysis showed that the A-PS repeating unit is linked to a nonterminal α-(1 → 3)-linked Man of the "capped core" glycoform of outer core OS at position O-4 via a → 6)-[α-D-Man-α-(1 → 2)-α-D-Man-1-phosphate → 2]-α-D-Man-(1 → motif. In order to verify that O-PS and A-PS are attached to almost identical core glycoforms, we identified a putative α-mannosyltransferase (PG0129) in P. gingivalis W50 that may be involved in the formation of core OS. Inactivation of PG0129 led to the synthesis of deep-R-type LPS with a truncated core that lacks α-(1 → 3)-linked mannoses and is devoid of either O-PS or A-PS. This indicated that PG0129 is an α-1,3-mannosyltransferase required for synthesis of the outer core regions of both O-LPS and A-LPS in P. gingivalis. IMPORTANCE Porphyromonas gingivalis, a Gram-negative anaerobe, is considered to be an important etiologic agent in periodontal disease, and among the virulence factors produced by the organism are two lipopolysaccharides (LPSs), O-LPS and A-LPS. The structures of the O-PS and A-PS repeating units, the core oligosaccharide (OS), and the linkage of the O-PS repeating unit to the core OS in O-LPS have been elucidated by our group. It is important to establish whether the attachment site of the A-PS repeating unit to the core OS in A-LPS is similar to or differs from that of the O-PS repeating unit in O-LPS. As part of understanding the biosynthetic pathway of the two LPSs in P. gingivalis, PG0129 was identified as an α-mannosyltransferase that is involved in the synthesis of the outer core regions of both O-LPS and A-LPS.
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24
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Díaz L, Hoare A, Soto C, Bugueño I, Silva N, Dutzan N, Venegas D, Salinas D, Pérez-Donoso JM, Gamonal J, Bravo D. Changes in lipopolysaccharide profile of Porphyromonas gingivalis clinical isolates correlate with changes in colony morphology and polymyxin B resistance. Anaerobe 2015; 33:25-32. [PMID: 25638398 DOI: 10.1016/j.anaerobe.2015.01.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 01/19/2015] [Accepted: 01/27/2015] [Indexed: 01/19/2023]
Abstract
Virulence factors on the surface of Porphyromonas gingivalis constitute the first line of interaction with host cells and contribute to immune modulation and periodontitis progression. In order to characterize surface virulence factors present on P. gingivalis, we obtained clinical isolates from healthy and periodontitis subjects and compared them with reference strains. Colony morphology, aggregation in liquid medium, surface charge, membrane permeability to bactericidal compounds, novobiocin and polymyxin B resistance, capsule presence and lipopolysaccharide (LPS) profiles were evaluated. By comparing isolates from healthy and periodontitis subjects, differences in colony morphology and aggregation in liquid culture were found; the latter being similar to two reference strains. These differences were not a consequence of variations in bacterial surface charge. Furthermore, isolates also presented differences in polymyxin B and novobiocin resistance; isolates from healthy subjects were susceptible to polymyxin B and resistant to novobiocin and, in contrast, isolates from periodontitis subjects were resistant to polymyxin B and susceptible to novobiocin. These changes in antimicrobial resistance levels correlate with variations in LPS profiles, since -unlike periodontitis isolates-isolates from healthy samples synthesize LPS molecules lacking both O-antigen moieties and anionic polysaccharide. Additionally, this phenotype correlated with the absence of O-antigen ligase activity. Altogether, our results reveal novel variations on surface components of P. gingivalis isolates obtained from healthy and periodontitis subjects that could be associated with differences in bacterial virulence and periodontitis progression.
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Affiliation(s)
- Leonor Díaz
- Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile; Laboratory of Periodontal Biology, Conservative Dentistry Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
| | - Anilei Hoare
- Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile; Laboratory of Periodontal Biology, Conservative Dentistry Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
| | - Cristopher Soto
- Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
| | - Isaac Bugueño
- Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
| | - Nora Silva
- Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
| | - Nicolás Dutzan
- Laboratory of Periodontal Biology, Conservative Dentistry Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
| | - Darna Venegas
- Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
| | - Daniela Salinas
- Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
| | - José Manuel Pérez-Donoso
- BioNanotechnology and Microbiology Laboratory, Center for Bioinformatics and Integrative Biology (CBIB), Faculty of Biological Sciences, Universidad Andres Bello, Santiago, Chile
| | - Jorge Gamonal
- Laboratory of Periodontal Biology, Conservative Dentistry Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
| | - Denisse Bravo
- Oral Microbiology Laboratory, Pathology and Oral Medicine Department, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.
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25
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Dai L, DeFee MR, Cao Y, Wen J, Wen X, Noverr MC, Qin Z. Lipoteichoic acid (LTA) and lipopolysaccharides (LPS) from periodontal pathogenic bacteria facilitate oncogenic herpesvirus infection within primary oral cells. PLoS One 2014; 9:e101326. [PMID: 24971655 PMCID: PMC4074159 DOI: 10.1371/journal.pone.0101326] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 06/05/2014] [Indexed: 02/03/2023] Open
Abstract
Kaposi's sarcoma (KS) remains the most common tumor arising in patients with HIV/AIDS, and involvement of the oral cavity represents one of the most common clinical manifestations of this tumor. HIV infection incurs an increased risk for periodontal diseases and oral carriage of a variety of bacteria. Whether interactions involving pathogenic bacteria and oncogenic viruses in the local environment facilitate replication or maintenance of these viruses in the oral cavity remains unknown. In the current study, our data indicate that pretreatment of primary human oral fibroblasts with two prototypical pathogen-associated molecular patterns (PAMPs) produced by oral pathogenic bacteria-lipoteichoic acid (LTA) and lipopolysaccharide (LPS), increase KSHV entry and subsequent viral latent gene expression during de novo infection. Further experiments demonstrate that the underlying mechanisms induced by LTA and/or LPS include upregulation of cellular receptor, increasing production of reactive oxygen species (ROS), and activating intracellular signaling pathways such as MAPK and NF-κB, and all of which are closely associated with KSHV entry or gene expression within oral cells. Based on these findings, we hope to provide the framework of developing novel targeted approaches for treatment and prevention of oral KSHV infection and KS development in high-risk HIV-positive patients.
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Affiliation(s)
- Lu Dai
- Research Center for Translational Medicine and Key Laboratory of Arrhythmias. East Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Medicine, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center, New Orleans, Louisiana, United States of America
| | - Michael R. DeFee
- Department of Oral Health Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Yueyu Cao
- Research Center for Translational Medicine and Key Laboratory of Arrhythmias. East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jiling Wen
- Department of Urology, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiaofei Wen
- Department of Urology, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Mairi C. Noverr
- Department of Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center, New Orleans, Louisiana, United States of America
| | - Zhiqiang Qin
- Research Center for Translational Medicine and Key Laboratory of Arrhythmias. East Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Microbiology/Immunology/Parasitology, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center, New Orleans, Louisiana, United States of America
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Gualtero Escobar DF, Porras Gaviria JP, Bernau Gutierrez S, Buitrago Ramírez DM, Castillo Perdomo DM, Lafaurie Villamil GI. Purificación y caracterización de lipopolisacáridos de Eikenella corrodens 23834 y Porphyromonas gingivalis W83. REVISTA COLOMBIANA DE BIOTECNOLOGÍA 2014. [DOI: 10.15446/rev.colomb.biote.v16n1.44224] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Shoji M, Sato K, Yukitake H, Naito M, Nakayama K. Involvement of the Wbp pathway in the biosynthesis of Porphyromonas gingivalis lipopolysaccharide with anionic polysaccharide. Sci Rep 2014; 4:5056. [PMID: 24852504 PMCID: PMC4031482 DOI: 10.1038/srep05056] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 05/06/2014] [Indexed: 11/15/2022] Open
Abstract
The periodontal pathogen Porphyromonas gingivalis has two different lipopolysaccharide (LPS) molecules, O-LPS and A-LPS. We have recently shown that P. gingivalis strain HG66 lacks A-LPS. Here, we found that introduction of a wild-type wbpB gene into strain HG66 restored formation of A-LPS. Sequencing of the wbpB gene from strain HG66 revealed the presence of a nonsense mutation in the gene. The wbpB gene product is a member of the Wbp pathway, which plays a role in the synthesis of UDP-ManNAc(3NAc)A in Pseudomonas aeruginosa; UDP-ManNAc(3NAc)A is sequentially synthesized by the WbpA, WbpB, WbpE, WbpD and WbpI proteins. We then determined the effect of the PGN_0002 gene, a wbpD homolog, on the biosynthesis of A-LPS. A PGN_0002-deficient mutant demonstrated an A-LPS biosynthesis deficiency. Taken together with previous studies, the present results suggest that the final product synthesized by the Wbp pathway is one of the sugar substrates necessary for the biosynthesis of A-LPS.
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Affiliation(s)
- Mikio Shoji
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
| | - Keiko Sato
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
| | - Hideharu Yukitake
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
| | - Mariko Naito
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
| | - Koji Nakayama
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
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Abstract
Mannose is an important sugar in the biology of the Gram-negative bacterium Porphyromonas gingivalis. It is a major component of the oligosaccharides attached to the Arg-gingipain cysteine proteases, the repeating units of an acidic lipopolysaccharide (A-LPS), and the core regions of both types of LPS produced by the organism (O-LPS and A-LPS) and a reported extracellular polysaccharide (EPS) isolated from spent culture medium. The organism occurs at inflamed sites in periodontal tissues, where it is exposed to host glycoproteins rich in mannose, which may be substrates for the acquisition of mannose by P. gingivalis. Five potential mannosidases were identified in the P. gingivalis W83 genome that may play a role in mannose acquisition. Four mannosidases were characterized in this study: PG0032 was a β-mannosidase, whereas PG0902 and PG1712 were capable of hydrolyzing p-nitrophenyl α-d-mannopyranoside. PG1711 and PG1712 were α-1 → 3 and α-1 → 2 mannosidases, respectively. No enzyme function could be assigned to PG0973. α-1 → 6 mannobiose was not hydrolyzed by P. gingivalis W50. EPS present in the culture supernatant was shown to be identical to yeast mannan and a component of the medium used for culturing P. gingivalis and was resistant to hydrolysis by mannosidases. Synthesis of O-LPS and A-LPS and glycosylation of the gingipains appeared to be unaffected in all mutants. Thus, α- and β-mannosidases of P. gingivalis are not involved in the harnessing of mannan/mannose from the growth medium for these biosynthetic processes. P. gingivalis grown in chemically defined medium devoid of carbohydrate showed reduced α-mannosidase activity (25%), suggesting these enzymes are environmentally regulated.
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Shoji M, Yukitake H, Sato K, Shibata Y, Naito M, Aduse-Opoku J, Abiko Y, Curtis MA, Nakayama K. Identification of an O-antigen chain length regulator, WzzP, in Porphyromonas gingivalis. Microbiologyopen 2013; 2:383-401. [PMID: 23509024 PMCID: PMC3684754 DOI: 10.1002/mbo3.84] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 02/11/2013] [Accepted: 02/19/2013] [Indexed: 01/22/2023] Open
Abstract
The periodontal pathogen Porphyromonas gingivalis has two different lipopolysaccharides (LPSs) designated O-LPS and A-LPS, which are a conventional O-antigen polysaccharide and an anionic polysaccharide that are both linked to lipid A-cores, respectively. However, the precise mechanisms of LPS biosynthesis remain to be determined. In this study, we isolated a pigment-less mutant by transposon mutagenesis and identified that the transposon was inserted into the coding sequence PGN_2005, which encodes a hypothetical protein of P. gingivalis ATCC 33277. We found that (i) LPSs purified from the PGN_2005 mutant were shorter than those of the wild type; (ii) the PGN_2005 protein was located in the inner membrane fraction; and (iii) the PGN_2005 gene conferred Wzz activity upon an Escherichia coli wzz mutant. These results indicate that the PGN_2005 protein, which was designated WzzP, is a functional homolog of the Wzz protein in P. gingivalis. Comparison of amino acid sequences among WzzP and conventional Wzz proteins indicated that WzzP had an additional fragment at the C-terminal region. In addition, we determined that the PGN_1896 and PGN_1233 proteins and the PGN_1033 protein appear to be WbaP homolog proteins and a Wzx homolog protein involved in LPS biosynthesis, respectively.
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Affiliation(s)
- Mikio Shoji
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
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A novel class of lipoprotein lipase-sensitive molecules mediates Toll-like receptor 2 activation by Porphyromonas gingivalis. Infect Immun 2013; 81:1277-86. [PMID: 23381996 DOI: 10.1128/iai.01036-12] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infection by the chronic periodontitis-associated pathogen Porphyromonas gingivalis activates a Toll-like receptor 2 (TLR2) response that triggers inflammation in the host but also promotes bacterial persistence. Our aim was to define ligands on the surfaces of intact P. gingivalis cells that determine its ability to activate TLR2. Molecules previously reported as TLR2 agonists include lipopolysaccharide (LPS), fimbriae, the lipoprotein PG1828, and phosphoceramides. We demonstrate that these molecules do not comprise the major factors responsible for stimulating TLR2 by whole bacterial cells. First, P. gingivalis mutants devoid of the reported protein agonists, PG1828 and fimbriae, activate TLR2 as strongly as the wild type. Second, two-phase extraction of whole bacteria resulted in a preponderance of TLR2 agonist activity partitioning to the hydrophilic phase, demonstrating that phosphoceramides are not a major TLR2 ligand. Third, analysis of LPS revealed that TLR2 activation is independent of lipid A structural variants. Instead, activation of TLR2 and TLR2/TLR1 by LPS is in large part due to copurifying molecules that are sensitive to the action of the enzyme lipoprotein lipase. Strikingly, intact P. gingivalis bacterial cells treated with lipoprotein lipase were attenuated in their ability to activate TLR2. We propose that a novel class of molecules comprised by lipoproteins constitutes the major determinants that confer to P. gingivalis the ability to stimulate TLR2 signaling.
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31
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Bostanci N, Belibasakis GN. Porphyromonas gingivalis: an invasive and evasive opportunistic oral pathogen. FEMS Microbiol Lett 2012; 333:1-9. [PMID: 22530835 DOI: 10.1111/j.1574-6968.2012.02579.x] [Citation(s) in RCA: 360] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 04/18/2012] [Accepted: 04/20/2012] [Indexed: 12/22/2022] Open
Abstract
Porphyromonas gingivalis is a Gram-negative oral anaerobe that is involved in the pathogenesis of periodontitis, an inflammatory disease that destroys the tissues supporting the tooth, eventually leading to tooth loss. Porphyromonas gingivalis has can locally invade periodontal tissues and evade the host defence mechanisms. In doing so, it utilizes a panel of virulence factors that cause deregulation of the innate immune and inflammatory responses. The present review discusses the invasive and evasive strategies of P. gingivalis and the role of its major virulence factors in these, namely lipopolysaccharide, capsule, gingipains and fimbriae. Moreover, the role of P. gingivalis as a 'keystone' biofilm species in orchestrating a host response, is highlighted.
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Affiliation(s)
- Nagihan Bostanci
- Oral Translational Research, Institute of Oral Biology, Center of Dental Medicine, Faculty of Medicine, University of Zürich, Zürich, Switzerland
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Ruan X, Loyola DE, Marolda CL, Perez-Donoso JM, Valvano MA. The WaaL O-antigen lipopolysaccharide ligase has features in common with metal ion-independent inverting glycosyltransferases. Glycobiology 2011; 22:288-99. [PMID: 21983211 DOI: 10.1093/glycob/cwr150] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
WaaL is a membrane enzyme that catalyzes a key step in lipopolysaccharide (LPS) synthesis: the glycosidic bonding of a sugar at the proximal end of the undecaprenyl-diphosphate (Und-PP) O-antigen with a terminal sugar of the lipid A-core oligosaccharide (OS). Utilizing an in vitro assay, we demonstrate here that ligation with purified Escherichia coli WaaL occurs without adenosine-5'-triphosphate (ATP) and magnesium ions. Furthermore, E. coli and Pseudomonas aeruginosa WaaL proteins cannot catalyze ATP hydrolysis in vitro. We also show that a lysine substitution of the arginine (Arg)-215 residue renders an active protein, whereas WaaL mutants with alanine replacements in the periplasmic-exposed residues Arg-215, Arg-288 and histidine (His)-338 and also the membrane-embedded aspartic acid-389 are nonfunctional. An in silico approach, combining predicted topological information with the analysis of sequence conservation, confirms the importance of a positive charge at the small periplasmic loop of WaaL, since an Arg corresponding to Arg-215 was found at a similar position in all the WaaL homologs. Also, a universally conserved H[NSQ]X(9)GXX[GTY] motif spanning the C-terminal end of the predicted large periplasmic loop and the membrane boundary of the transmembrane helix was identified. The His residue in this motif corresponds to His-338. A survey of LPS structures in which the linkage between O-antigen and lipid A-core OS was elucidated reveals that it is always in the β-configuration, whereas the sugars bound to Und-PP are in the α-configuration. Together, our biochemical and in silico data argue that WaaL proteins use a common reaction mechanism and share features of metal ion-independent inverting glycosyltransferases.
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Affiliation(s)
- Xiang Ruan
- Centre for Human Immunology, Department of Microbiology and Immunology, University of Western Ontario, London, ON, Canada
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Shoji M, Sato K, Yukitake H, Kondo Y, Narita Y, Kadowaki T, Naito M, Nakayama K. Por secretion system-dependent secretion and glycosylation of Porphyromonas gingivalis hemin-binding protein 35. PLoS One 2011; 6:e21372. [PMID: 21731719 PMCID: PMC3120885 DOI: 10.1371/journal.pone.0021372] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 05/26/2011] [Indexed: 01/22/2023] Open
Abstract
The anaerobic Gram-negative bacterium Porphyromonas gingivalis is a major pathogen in severe forms of periodontal disease and refractory periapical perodontitis. We have recently found that P. gingivalis has a novel secretion system named the Por secretion system (PorSS), which is responsible for secretion of major extracellular proteinases, Arg-gingipains (Rgps) and Lys-gingipain. These proteinases contain conserved C-terminal domains (CTDs) in their C-termini. Hemin-binding protein 35 (HBP35), which is one of the outer membrane proteins of P. gingivalis and contributes to its haem utilization, also contains a CTD, suggesting that HBP35 is translocated to the cell surface via the PorSS. In this study, immunoblot analysis of P. gingivalis mutants deficient in the PorSS or in the biosynthesis of anionic polysaccharide-lipopolysaccharide (A-LPS) revealed that HBP35 is translocated to the cell surface via the PorSS and is glycosylated with A-LPS. From deletion analysis with a GFP-CTD[HBP35] green fluorescent protein fusion, the C-terminal 22 amino acid residues of CTD[HBP35] were found to be required for cell surface translocation and glycosylation. The GFP-CTD fusion study also revealed that the CTDs of CPG70, peptidylarginine deiminase, P27 and RgpB play roles in PorSS-dependent translocation and glycosylation. However, CTD-region peptides were not found in samples of glycosylated HBP35 protein by peptide map fingerprinting analysis, and antibodies against CTD-regions peptides did not react with glycosylated HBP35 protein. These results suggest both that the CTD region functions as a recognition signal for the PorSS and that glycosylation of CTD proteins occurs after removal of the CTD region. Rabbits were used for making antisera against bacterial proteins in this study.
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Affiliation(s)
- Mikio Shoji
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Keiko Sato
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Hideharu Yukitake
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Yoshio Kondo
- Department of Pediatric Dentistry, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Yuka Narita
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Tomoko Kadowaki
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Mariko Naito
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Koji Nakayama
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
- Global COE Program at Nagasaki University, Nagasaki, Japan
- * E-mail:
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Chen YY, Peng B, Yang Q, Glew MD, Veith PD, Cross KJ, Goldie KN, Chen D, O'Brien-Simpson N, Dashper SG, Reynolds EC. The outer membrane protein LptO is essential for the O-deacylation of LPS and the co-ordinated secretion and attachment of A-LPS and CTD proteins in Porphyromonas gingivalis. Mol Microbiol 2011; 79:1380-401. [DOI: 10.1111/j.1365-2958.2010.07530.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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35
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Ruiz-Matute AI, Hernández-Hernández O, Rodríguez-Sánchez S, Sanz ML, Martínez-Castro I. Derivatization of carbohydrates for GC and GC-MS analyses. J Chromatogr B Analyt Technol Biomed Life Sci 2010; 879:1226-40. [PMID: 21186143 DOI: 10.1016/j.jchromb.2010.11.013] [Citation(s) in RCA: 237] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 09/29/2010] [Accepted: 11/08/2010] [Indexed: 11/26/2022]
Abstract
GC and GC-MS are excellent techniques for the analysis of carbohydrates; nevertheless the preparation of adequate derivatives is necessary. The different functional groups that can be found and the diversity of samples require specific methods. This review aims to collect the most important methodologies currently used, either published as new procedures or as new applications, for the analysis of carbohydrates. A high diversity of compounds with diverse functionalities has been selected: neutral carbohydrates (saccharides and polyalcohols), sugar acids, amino and iminosugars, polysaccharides, glycosides, glycoconjugates, anhydrosugars, difructose anhydrides and products resulting of Maillard reaction (osuloses, Amadori compounds). Chiral analysis has also been considered, describing the use of diastereomers and derivatives to be eluted on chiral stationary phases.
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Affiliation(s)
- A I Ruiz-Matute
- Instituto de Fermentaciones Industriales-CIAL (CSIC), Juan de la Cierva 3, 28006 Madrid, Spain
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C-terminal domain residues important for secretion and attachment of RgpB in Porphyromonas gingivalis. J Bacteriol 2010; 193:132-42. [PMID: 20971915 DOI: 10.1128/jb.00773-10] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Porphyromonas gingivalis, a periodontal pathogen, expresses a group of surface proteins with a common C-terminal domain (CTD) that are exported by a novel secretion system to the surface, where they are covalently attached. Using RgpB as a model CTD protein, we have produced a series of site-directed mutations in the CTD sequence at conserved residues and at residues that may be modified and, hence, surface attached. The mutant RgpB proteins were expressed in a P. gingivalis host lacking functional RgpB and RgpA Arg-specific proteases. The RgpB mutants produced were Y674F, Y674F Y718F, T675Q S679Q T682Q T684Q, T693Q, F695A, D696A, N698A, G699P, G716P, T724Q, T728Q T730Q, and K732Q and a protein with a deletion of residues 692 to 702 (Δ692-702). The mutants were characterized for cell-associated Arg-specific protease activity and for cellular distribution using anti-Rgp antibodies and Western blotting of culture fractions. All the mutants exhibited cell-associated Arg-specific activity similar to that of the positive control except for the D696A and Δ692-702 mutants. For all mutants, except D696A and Δ692-702, the RgpB proteins were found modified and attached to the cell surface, which was the same profile found in the positive-control strain. Only trace amounts of the precursor form of the Δ692-702 mutant were detected in the outer membrane, with none detected in the periplasm or culture fluid although cell transcript levels were normal. The results suggest that residues 692 to 702 of the CTD, in particular, residue D696, have an important role in the attachment of RgpB at the cell surface and that without attachment secretion does not occur.
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A Porphyromonas gingivalis mutant defective in a putative glycosyltransferase exhibits defective biosynthesis of the polysaccharide portions of lipopolysaccharide, decreased gingipain activities, strong autoaggregation, and increased biofilm formation. Infect Immun 2010; 78:3801-12. [PMID: 20624909 DOI: 10.1128/iai.00071-10] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Gram-negative anaerobic bacterium Porphyromonas gingivalis is a major pathogen in periodontal disease, one of the biofilm-caused infectious diseases. The bacterium possesses potential virulence factors, including fimbriae, proteinases, hemagglutinin, lipopolysaccharide (LPS), and outer membrane vesicles, and some of these factors are associated with biofilm formation; however, the precise mechanism of biofilm formation is still unknown. Colonial pigmentation of the bacterium on blood agar plates is related to its virulence. In this study, we isolated a nonpigmented mutant that had an insertion mutation within the new gene PGN_1251 (gtfB) by screening a transposon insertion library. The gene shares homology with genes encoding glycosyltransferase 1 of several bacteria. The gtfB mutant was defective in biosynthesis of both LPSs containing O side chain polysaccharide (O-LPS) and anionic polysaccharide (A-LPS). The defect in the gene resulted in a complete loss of surface-associated gingipain proteinases, strong autoaggregation, and a marked increase in biofilm formation, suggesting that polysaccharide portions of LPSs influence attachment of gingipain proteinases to the cell surface, autoaggregation, and biofilm formation of P. gingivalis.
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The native 67-kilodalton minor fimbria of Porphyromonas gingivalis is a novel glycoprotein with DC-SIGN-targeting motifs. J Bacteriol 2010; 192:4103-10. [PMID: 20562309 DOI: 10.1128/jb.00275-10] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We recently reported that the oral mucosal pathogen Porphyromonas gingivalis, through its 67-kDa Mfa1 (minor) fimbria, targets the C-type lectin receptor DC-SIGN for invasion and persistence within human monocyte-derived dendritic cells (DCs). The DCs respond by inducing an immunosuppressive and Th2-biased CD4(+) T-cell response. We have now purified the native minor fimbria by ion-exchange chromatography and sequenced the fimbria by tandem mass spectrometry (MS/MS), confirming its identity and revealing two putative N-glycosylation motifs as well as numerous putative O-glycosylation sites. We further show that the minor fimbria is glycosylated by ProQ staining and that glycosylation is partially removed by treatment with beta(1-4)-galactosidase, but not by classic N- and O-linked deglycosidases. Further monosaccharide analysis by gas chromatography-mass spectrometry (GC-MS) confirmed that the minor fimbria contains the DC-SIGN-targeting carbohydrates fucose (1.35 nmol/mg), mannose (2.68 nmol/mg), N-acetylglucosamine (2.27 nmol/mg), and N-acetylgalactosamine (0.652 nmol/mg). Analysis by transmission electron microscopy revealed that the minor fimbria forms fibers approximately 200 nm in length that could be involved in targeting or cross-linking DC-SIGN. These findings shed further light on molecular mechanisms of invasion and immunosuppression by this unique mucosal pathogen.
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Pathirana RD, O'Brien-Simpson NM, Reynolds EC. Host immune responses to Porphyromonas gingivalis antigens. Periodontol 2000 2010; 52:218-37. [DOI: 10.1111/j.1600-0757.2009.00330.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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