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Chu L, Wu Y, Xu X, Phillips L, Kolodrubetz D. Glutathione catabolism by Treponema denticola impacts its pathogenic potential. Anaerobe 2020; 62:102170. [PMID: 32044394 PMCID: PMC7153967 DOI: 10.1016/j.anaerobe.2020.102170] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 01/14/2020] [Accepted: 02/04/2020] [Indexed: 12/28/2022]
Abstract
Treponema denticola is a spirochete that is etiologic for periodontal diseases. This bacterium is one of two periodontal pathogens that have been shown to have a complete three step enzymatic pathway (GTSP) that catabolizes glutathione to H2S. This pathway may contribute to the tissue pathology seen in periodontitis since diseased periodontal pockets have lower glutathione levels than healthy sites with a concomitant increase in H2S concentration. In order to be able to demonstrate that glutathione catabolism by the GTSP is critical for the pathogenic potential of T. denticola, allelic replacement mutagenesis was used to make a deletion mutant (Δggt) in the gene encoding the first enzyme in the GTSP. The mutant cannot produce H2S from glutathione since it lacks gamma-glutamyltransferase (GGT) activity. The hemolytic and hemoxidation activities of wild type T. denticola plus glutathione are reduced to background levels with the Δggt mutant and the mutant has lost the ability to grow aerobically when incubated with glutathione. The Δggt bacteria with glutathione cause less cell death in human gingival fibroblasts (hGFs) in vitro than do wild type T. denticola and the levels of hGF death correlate with the amounts of H2S produced. Importantly, the mutant spirochetes plus glutathione make significantly smaller lesions than wild type bacteria plus glutathione in a mouse back lesion model that assesses soft tissue destruction, a major symptom of periodontal diseases. Our results are the first to prove that T. denticola thiol-compound catabolism by its gamma-glutamyltransferase can play a significant role in the in the types of host tissue damage seen in periodontitis.
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Affiliation(s)
- Lianrui Chu
- Department of Developmental Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Yimin Wu
- Department of Developmental Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Xiaoping Xu
- Department of Periodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Linda Phillips
- Department of Microbiology, Immunology and Molecular Genetics, UT Health San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA
| | - David Kolodrubetz
- Department of Microbiology, Immunology and Molecular Genetics, UT Health San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA.
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Abstract
Oral Treponema species, most notably T. denticola, are implicated in the destructive effects of human periodontal disease. Progress in the molecular analysis of interactions between T. denticola and host proteins is reviewed here, with particular emphasis on the characterization of surface-expressed and secreted proteins of T. denticola involved in interactions with host cells, extracellular matrix components, and components of the innate immune system.
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Affiliation(s)
- J. Christopher Fenno
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
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Bernardini C, Gaibani P, Zannoni A, Vocale C, Bacci ML, Piana G, Forni M, Sambri V. Treponema denticola alters cell vitality and induces HO-1 and Hsp70 expression in porcine aortic endothelial cells. Cell Stress Chaperones 2010; 15:509-16. [PMID: 20091146 PMCID: PMC3006620 DOI: 10.1007/s12192-009-0164-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 11/19/2009] [Accepted: 11/23/2009] [Indexed: 02/07/2023] Open
Abstract
Treponema denticola is an oral spirochete that is associated with periodontal disease and detected occasionally in extraoral lesions associated with systemic disorders such as cardiovascular diseases. The effect of specific bacterial products from oral treponemes on endothelium is poorly investigated. This study analyzed the ability of components of the outer membrane of T. denticola (OMT) to induce apoptosis and heat shock proteins (HO-1 and Hsp70) in porcine aortic endothelial cells (pAECs), compared with results obtained with classical pro-inflammatory lipopolysaccharide (LPS) treatment. Cellular apoptosis was detected when pAECs were treated with either OMT or LPS, suggesting that OMT can damage endothelium integrity by reducing endothelial cell vitality. Stimulation with OMT, similarly to LPS response, increased HO-1 and Hsp-70 protein expression in a time-dependent manner, correlating with a rise in HO-1 and Hsp-70 mRNA. Collectively, these results support the hypothesis that T. denticola alters endothelial cell function. Moreover, our in vitro experiments represent a preliminary investigation to further in vivo study using a pig model to elucidate how T. denticola leaves the initial endodontic site and participates in the development of several systemic diseases.
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Affiliation(s)
- Chiara Bernardini
- Department of Veterinary Morphophysiology and Animal Production (DIMORFIPA), University of Bologna, Bologna, Italy.
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Immune response and alveolar bone resorption in a mouse model of Treponema denticola infection. Infect Immun 2008; 77:694-8. [PMID: 19015247 DOI: 10.1128/iai.01004-08] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Treponema denticola is considered to be an agent strongly associated with periodontal disease. The lack of an animal infection model has hampered the understanding of T. denticola pathogenesis and the host's immune response to infection. In this study, we have established an oral infection model in mice, demonstrating that infection by oral inoculation is feasible. The presence of T. denticola in the oral cavities of the animals was confirmed by PCR. Mice given T. denticola developed a specific immune response to the bacterium. The antibodies generated from the infection were mainly of the immunoglobulin G1 subclass, indicating a Th2-tilted response. The antibodies recognized 11 T. denticola proteins, of which a 62-kDa and a 53-kDa protein were deemed immunodominant. The two proteins were identified, respectively, as dentilisin and the major outer sheath protein by mass spectrometry. Splenocytes cultured from the infected mice no longer produced interleukin-10 and produced markedly reduced levels of gamma interferon relative to those produced by naïve splenocytes upon stimulation with T. denticola. Mandibles of infected mice showed significantly greater bone resorption (P < 0.01) than those of mock-infected controls.
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Bodet C, Chandad F, Grenier D. Potentiel pathogénique de Porphyromonas gingivalis, Treponema denticola et Tannerella forsythia, le complexe bactérien rouge associé à la parodontite. ACTA ACUST UNITED AC 2007; 55:154-62. [PMID: 17049750 DOI: 10.1016/j.patbio.2006.07.045] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Accepted: 07/28/2006] [Indexed: 11/30/2022]
Abstract
Periodontitis are mixed bacterial infections leading to destruction of tooth-supporting tissues, including periodontal ligament and alveolar bone. Among over 500 bacterial species living in the oral cavity, a bacterial complex named "red complex" and made of Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia has been strongly related to advanced periodontal lesions. While periodontopathogenic bacteria are the primary etiologic factor of periodontitis, tissue destruction essentially results from the host immune response to the bacterial challenge. Members of the red complex are Gram negative anaerobic bacteria expressing numerous virulence factors allowing bacteria to colonize the subgingival sites, to disturb the host defense system, to invade and destroy periodontal tissue as well as to promote the immunodestructive host response. This article reviews current knowledge of the pathogenic mechanisms of bacteria of the red complex leading to tissue and alveolar bone destruction observed during periodontitis.
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Affiliation(s)
- C Bodet
- Groupe de recherche en écologie buccale, faculté de médecine dentaire, université Laval, G1K 7P4 Québec, Québec, Canada
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Foschi F, Izard J, Sasaki H, Sambri V, Prati C, Müller R, Stashenko P. Treponema denticola in disseminating endodontic infections. J Dent Res 2006; 85:761-5. [PMID: 16861296 PMCID: PMC3579618 DOI: 10.1177/154405910608500814] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Treponema denticola is a consensus periodontal pathogen that has recently been associated with endodontic pathology. In this study, the effect of mono-infection of the dental pulp with T. denticola and with polymicrobial "red-complex" organisms (RC) (Porphyromonas gingivalis, Tannerella forsythia, and T. denticola) in inducing disseminating infections in wild-type (WT) and severe-combined-immunodeficiency (SCID) mice was analyzed. After 21 days, a high incidence (5/10) of orofacial abscesses was observed in SCID mice mono-infected with T. denticola, whereas abscesses were rare in SCID mice infected with the red-complex organisms or in wild-type mice. Splenomegaly was present in all groups, but only mono-infected SCID mice had weight loss. T. denticola DNA was detected in the spleen, heart, and brain of mono-infected SCID mice and in the spleen from mono-infected wild-type mice, which also had more periapical bone resorption. The results indicate that T. denticola has high pathogenicity, including dissemination to distant organs, further substantiating its potential importance in oral and linked systemic conditions.
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Affiliation(s)
- F. Foschi
- Department of Cytokine Biology, The Forsyth Institute, 140 The Fenway, Boston, MA 02115, USA
- Endodontics Unit, Department of Oral Sciences, University of Bologna, Italy
| | - J. Izard
- Department of Molecular Genetics, The Forsyth Institute, Boston, MA, USA
| | - H. Sasaki
- Department of Cytokine Biology, The Forsyth Institute, 140 The Fenway, Boston, MA 02115, USA
| | - V. Sambri
- Section of Microbiology, DMCSS, Ospedale S. Orsola, University of Bologna, Italy
| | - C. Prati
- Endodontics Unit, Department of Oral Sciences, University of Bologna, Italy
| | - R. Müller
- Institute for Biomedical Engineering, ETH, and University of Zürich, Switzerland
| | - P. Stashenko
- Department of Cytokine Biology, The Forsyth Institute, 140 The Fenway, Boston, MA 02115, USA
- *corresponding author,
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Shenker BJ, Demuth DR, Zekavat A. Exposure of lymphocytes to high doses of Actinobacillus actinomycetemcomitans cytolethal distending toxin induces rapid onset of apoptosis-mediated DNA fragmentation. Infect Immun 2006; 74:2080-92. [PMID: 16552037 PMCID: PMC1418899 DOI: 10.1128/iai.74.4.2080-2092.2006] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
We have shown previously that treatment of human lymphocytes with the Actinobacillus actinomycetemcomitans cytolethal distending toxin (Cdt) results in dose-dependent G2 arrest, followed 24 h later by apoptotic cell death. Here we demonstrated that for Jurkat cells exposed to high concentrations of Cdt (>0.2 ng/ml) there was a dose-dependent increase in the level of S-phase cells and a concomitant decrease in the level of G2 cells. Fluorescence-activated cell sorter analysis demonstrated that the S-phase cells did not incorporate BrdU and likely represented cells that arrested in G2 and underwent significant DNA fragmentation. Analysis of the kinetics of the appearance of both S-phase cells and apoptotic cells supported this interpretation. Cells exposed to low doses of toxin exhibited G2 arrest at 24 h, but at 48 and 72 h there were also decreases in the level of G2 cells and concomitant increases in the levels of S, G0/G1, and sub-G0 cells; these changes were paralleled by increased numbers of apoptotic cells. Cells exposed to high doses of toxin exhibited these changes 24 to 48 h earlier. We also examined the relationship between G2 arrest, DNA fragmentation, and activation of the apoptotic cascade. We employed two inhibitors of apoptosis, overexpression of Bcl-2 and the caspase-3 inhibitor zvad. Both inhibitors blocked Cdt-induced apoptosis, Cdt-induced DNA fragmentation, and phosphorylation of the histone H2AX. However, the cells retained the ability to undergo G2 arrest in the presence of the toxin. Thus, it appears that high doses of Cdt induce rapid onset of DNA degradation resulting from activation of the apoptotic cascade.
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Affiliation(s)
- Bruce J Shenker
- Department of Pathology, University of Pennsylvania School of Dental Medicine, 240 South 40th Street, Philadelphia, PA 19104-2030, USA.
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Holt SC, Ebersole JL. Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia: the "red complex", a prototype polybacterial pathogenic consortium in periodontitis. Periodontol 2000 2005; 38:72-122. [PMID: 15853938 DOI: 10.1111/j.1600-0757.2005.00113.x] [Citation(s) in RCA: 629] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Stanley C Holt
- Department of Periodontology, The Forsyth Institute, Boston, MA, USA
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Affiliation(s)
- Richard P Ellen
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
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