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Kurniyati K, Chang Y, Liu J, Li C. Transcriptional and functional characterizations of multiple flagellin genes in spirochetes. Mol Microbiol 2022; 118:175-190. [PMID: 35776658 PMCID: PMC9481697 DOI: 10.1111/mmi.14959] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/28/2022] [Accepted: 06/28/2022] [Indexed: 11/28/2022]
Abstract
The flagellar filament is a helical propeller for bacterial locomotion. In external flagellates, the filaments are mostly homopolymers of a single flagellin protein. By contrast, the flagellar filaments of spirochetes are mostly heteropolymers of multiple flagellin proteins. This report seeks to investigate the role of multiple flagellin proteins using the oral spirochete Treponema denticola as a model. First, biochemical and genetic studies uncover that the flagellar filaments of T. denticola mainly comprise four proteins, FlaA, FlaB1, FlaB2, and FlaB3, in a defined stoichiometry. Second, transcriptional analyses reveal that the genes encoding these four proteins are regulated by two different transcriptional factors, sigma28 and sigma70 . Third, loss-of-function studies demonstrate that each individual flagellin protein contributes to spirochete motility, but none of them is absolutely required. Last, we provide genetic and structural evidence that FlaA forms a "seam"-like structure around the core and that deletion of individual flagellin protein alters the flagellar homeostasis. Collectively, these results demonstrate that T. denticola has evolved a unique mechanism to finely regulate its flagellar filament gene expression and assembly which renders the organelle with the right number, shape, strength, and structure for its distinct motility.
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Affiliation(s)
- Kurni Kurniyati
- Department of Oral Craniofacial Molecular Biology, School of DentistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Yunjie Chang
- Microbial Sciences InstituteYale UniversityWest HavenConnecticutUSA
- Department of Microbial PathogenesisYale School of MedicineNew HavenConnecticutUSA
| | - Jun Liu
- Microbial Sciences InstituteYale UniversityWest HavenConnecticutUSA
- Department of Microbial PathogenesisYale School of MedicineNew HavenConnecticutUSA
| | - Chunhao Li
- Department of Oral Craniofacial Molecular Biology, School of DentistryVirginia Commonwealth UniversityRichmondVirginiaUSA
- Department of Microbiology and Immunology, School of MedicineVirginia Commonwealth UniversityRichmondVirginiaUSA
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2
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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3
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Yoo H, Jwa S, Kim D, Ji Y. Inhibitory effect of Streptococcus salivarius K12 and M18 on halitosis in vitro. Clin Exp Dent Res 2020; 6:207-214. [PMID: 32250565 PMCID: PMC7133729 DOI: 10.1002/cre2.269] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/11/2019] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The aim of the study was to observe the antimicrobial activity of Porphyromonas gingivalis and Treponema denticola as well as the effect on reducing volatile sulfur compounds (VSCs). MATERIALS AND METHODS After P. gingivalis and T. denticola were cultured with or without Streptococcus salivarius K12 and M18, VSCs were measured by Oral Chroma. In order to analyze the mechanism for malodor control, the antimicrobial activity of S. salivarius K12 and M18 against P. gingivalis and T. denticola was assessed. SPSS 21.0 was used for data analysis with the Kruskal-Wallis and Jonckheere-Terpstra tests. Mann-Whitney test was applied for post hoc analysis. RESULTS P. gingivalis and T. denticola VSC levels were reduced by high concentrations of S. salivarius K12 and M18 during coculture. The concentrations were lower than those of single culture (p < .05). An antimicrobial effect was detected on P. gingivalis, and T. denticola by 50% S. salivarius K12 and M18. The spent culture medium and whole bacteria of S. salivarius K12 and M18 reduced the levels of VSCs below the amount in a single culture of P. gingivalis and T. denticola (p < .05). CONCLUSION S. salivarius K12 and M18 decreased the levels of VSCs originating from P. gingivalis and T. denticola.
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Affiliation(s)
- Hyun‐Jun Yoo
- Department of Preventive DentistryDankook University College of DentistryRepublic of Korea
| | - Su‐Kyung Jwa
- Department of Dental HygieneUlsan CollegeRepublic of Korea
| | - Da‐Hui Kim
- Department of Preventive DentistryDankook University College of DentistryRepublic of Korea
| | - Yun‐Jeong Ji
- Herbal Crop Utilization Research Team, Department of Herbal Crop ResearchRural Development Administration (RDA)ChungbukRepublic of Korea
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Jones MM, Vanyo ST, Visser MB. The C-terminal region of the major outer sheath protein of Treponema denticola inhibits neutrophil chemotaxis. Mol Oral Microbiol 2017; 32:375-389. [PMID: 28296262 PMCID: PMC5585023 DOI: 10.1111/omi.12180] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2017] [Indexed: 12/25/2022]
Abstract
Treponema denticola is an oral spirochete strongly associated with severe periodontal disease. A prominent virulence factor, the major outer sheath protein (Msp), disorients neutrophil chemotaxis by altering the cellular phosphoinositide balance, leading to impairment of downstream chemotactic events including actin rearrangement, Rac1 activation, and Akt activation in response to chemoattractant stimulation. The specific regions of Msp responsible for interactions with neutrophils remain unknown. In this study, we investigated the inhibitory effect of truncated Msp regions on neutrophil chemotaxis and associated signaling pathways. Murine neutrophils were treated with recombinant protein truncations followed by assessment of chemotaxis and associated signal pathway activation. Chemotaxis assays indicate sequences within the C-terminal region; particularly the first 130 amino acids, have the strongest inhibitory effect on neutrophil chemotaxis. Neutrophils incubated with the C-terminal region protein also demonstrated the greatest inhibition of Rac1 activation, increased phosphoinositide phosphatase activity, and decreased Akt activation; orchestrating impairment of chemotaxis. Furthermore, incubation with antibodies specific to only the C-terminal region blocked the Msp-induced inhibition of chemotaxis and denaturing the protein restored Rac1 activation. Msp from the strain OTK, with numerous amino acid substitutions throughout the polypeptide, including the C-terminal region compared with strain 35405, showed increased ability to impair neutrophil chemotaxis. Collectively, these results indicate that the C-terminal region of Msp is the most potent region to modulate neutrophil chemotactic signaling and that specific sequences and structures are likely to be required. Knowledge of how spirochetes dampen the neutrophil response is limited and Msp may represent a novel therapeutic target for periodontal disease.
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Affiliation(s)
- Megan M. Jones
- State University of New York at Buffalo, 3435 Main St, Buffalo, NY 14214, USA
| | - Stephen T. Vanyo
- State University of New York at Buffalo, 3435 Main St, Buffalo, NY 14214, USA
| | - Michelle B. Visser
- State University of New York at Buffalo, 3435 Main St, Buffalo, NY 14214, USA
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Frederick RE, Caranto JD, Masitas CA, Gebhardt LL, MacGowan CE, Limberger RJ, Kurtz DM. Dioxygen and nitric oxide scavenging by Treponema denticola flavodiiron protein: a mechanistic paradigm for catalysis. J Biol Inorg Chem 2015; 20:603-13. [PMID: 25700637 PMCID: PMC4768905 DOI: 10.1007/s00775-015-1248-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/13/2015] [Indexed: 10/24/2022]
Abstract
Flavodiiron proteins (FDPs) contain a unique active site consisting of a non-heme diiron carboxylate site proximal to a flavin mononucleotide (FMN). FDPs serve as the terminal components for reductive scavenging of dioxygen (to water) or nitric oxide (to nitrous oxide), which combats oxidative or nitrosative stress in many bacteria. Characterizations of FDPs from spirochetes or from any oral microbes have not been previously reported. Here, we report characterization of an FDP from the anaerobic spirochete, Treponema (T.) denticola, which is associated with chronic periodontitis. The isolated T. denticola FDP exhibited efficient four-electron dioxygen reductase activity and lower but significant anaerobic nitric oxide reductase activity. A mutant T. denticola strain containing the inactivated FDP-encoding gene was significantly more air-sensitive than the wild-type strain. Single turnover reactions of the four-electron-reduced FDP (FMNH2-Fe(II)Fe(II)) (FDPred) with O2 monitored on the milliseconds to seconds time scale indicated initial rapid formation of a spectral feature consistent with a cis-μ-1,2-peroxo-diferric intermediate, which triggered two-electron oxidation of FMNH2. Reaction of FDPred with NO showed apparent cooperativity between binding of the first and second NO to the diferrous site. The resulting diferrous dinitrosyl complex triggered two-electron oxidation of the FMNH2. Our cumulative results on this and other FDPs indicate that smooth two-electron FMNH2 oxidation triggered by the FDPred/substrate complex and overall four-electron oxidation of FDPred to FDPox constitutes a mechanistic paradigm for both dioxygen and nitric oxide reductase activities of FDPs. Four-electron reductive O2 scavenging by FDPs could contribute to oxidative stress protection in many other oral bacteria.
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Affiliation(s)
- Rosanne E. Frederick
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Jonathan D. Caranto
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Cesar A. Masitas
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Linda L. Gebhardt
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Charles E. MacGowan
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Ronald J. Limberger
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Donald M. Kurtz
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
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6
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Tan KH, Seers CA, Dashper SG, Mitchell HL, Pyke JS, Meuric V, Slakeski N, Cleal SM, Chambers JL, McConville MJ, Reynolds EC. Porphyromonas gingivalis and Treponema denticola exhibit metabolic symbioses. PLoS Pathog 2014; 10:e1003955. [PMID: 24603978 PMCID: PMC3946380 DOI: 10.1371/journal.ppat.1003955] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 01/12/2014] [Indexed: 12/31/2022] Open
Abstract
Porphyromonas gingivalis and Treponema denticola are strongly associated with chronic periodontitis. These bacteria have been co-localized in subgingival plaque and demonstrated to exhibit symbiosis in growth in vitro and synergistic virulence upon co-infection in animal models of disease. Here we show that during continuous co-culture a P. gingivalis:T. denticola cell ratio of 6∶1 was maintained with a respective increase of 54% and 30% in cell numbers when compared with mono-culture. Co-culture caused significant changes in global gene expression in both species with altered expression of 184 T. denticola and 134 P. gingivalis genes. P. gingivalis genes encoding a predicted thiamine biosynthesis pathway were up-regulated whilst genes involved in fatty acid biosynthesis were down-regulated. T. denticola genes encoding virulence factors including dentilisin and glycine catabolic pathways were significantly up-regulated during co-culture. Metabolic labeling using 13C-glycine showed that T. denticola rapidly metabolized this amino acid resulting in the production of acetate and lactate. P. gingivalis may be an important source of free glycine for T. denticola as mono-cultures of P. gingivalis and T. denticola were found to produce and consume free glycine, respectively; free glycine production by P. gingivalis was stimulated by T. denticola conditioned medium and glycine supplementation of T. denticola medium increased final cell density 1.7-fold. Collectively these data show P. gingivalis and T. denticola respond metabolically to the presence of each other with T. denticola displaying responses that help explain enhanced virulence of co-infections. Unlike the traditional view that most diseases are caused by infection with a single bacterial species, some chronic diseases including periodontitis result from the perturbation of the natural microbiota and the proliferation of a number of opportunistic pathogens. Both Porphyromonas gingivalis and Treponema denticola have been associated with the progression and severity of chronic periodontitis and have been shown to display synergistic virulence in animal models. However, the underlying mechanisms to these observations are unclear. Here we demonstrate that these two bacteria grow synergistically in continuous co-culture and modify their gene expression. The expression of T. denticola genes encoding known virulence factors and enzymes involved in the uptake and metabolism of the amino acid glycine was up-regulated in co-culture. T. denticola stimulated the proteolytic P. gingivalis to produce free glycine, which T. denticola used as a major carbon source. Our study shows P. gingivalis and T. denticola co-operate metabolically and this helps to explain their synergistic virulence in animal models and their intimate association in vivo.
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Affiliation(s)
- Kheng H. Tan
- Oral Health CRC, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Christine A. Seers
- Oral Health CRC, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Stuart G. Dashper
- Oral Health CRC, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Helen L. Mitchell
- Oral Health CRC, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - James S. Pyke
- Oral Health CRC, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Vincent Meuric
- Oral Health CRC, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Nada Slakeski
- Oral Health CRC, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Steven M. Cleal
- Oral Health CRC, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Jenny L. Chambers
- Department of Biochemistry and Molecular Biology, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Malcolm J. McConville
- Department of Biochemistry and Molecular Biology, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Eric C. Reynolds
- Oral Health CRC, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
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7
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Abiko Y, Nagano K, Yoshida Y, Yoshimura F. Major membrane protein TDE2508 regulates adhesive potency in Treponema denticola. PLoS One 2014; 9:e89051. [PMID: 24586498 PMCID: PMC3931704 DOI: 10.1371/journal.pone.0089051] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Accepted: 01/13/2014] [Indexed: 12/13/2022] Open
Abstract
The cultivation and genetic manipulation of Treponema denticola, a Gram-negative oral spirochaeta associated with periodontal diseases, is still challenging. In this study, we formulated a simple medium based on a commercially available one, and established a transformation method with high efficiency. We then analyzed proteins in a membrane fraction in T. denticola and identified 16 major membrane-associated proteins, and characterized one of them, TDE2508, whose biological function was not yet known. Although this protein, which exhibited a complex conformation, was presumably localized in the outer membrane, we did not find conclusive evidence that it was exposed on the cell surface. Intriguingly, a TDE2508-deficient mutant exhibited significantly increased biofilm formation and adherent activity on human gingival epithelial cells. However, the protein deficiency did not alter autoaggregation, coaggregation with Porphyromonas gingivalis, hemagglutination, cell surface hydrophobicity, motility, or expression of Msp which was reported to be an adherent molecule in this bacteria. In conclusion, the major membrane protein TDE2508 regulates biofilm formation and the adhesive potency of T. denticola, although the underlying mechanism remains unclear.
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Affiliation(s)
- Yuki Abiko
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Kusumoto-cho, Chikusa-ku, Nagoya, Aichi, Japan
| | - Keiji Nagano
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Kusumoto-cho, Chikusa-ku, Nagoya, Aichi, Japan
- * E-mail:
| | - Yasuo Yoshida
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Kusumoto-cho, Chikusa-ku, Nagoya, Aichi, Japan
| | - Fuminobu Yoshimura
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Kusumoto-cho, Chikusa-ku, Nagoya, Aichi, Japan
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8
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Nagy A, Brugoviczky Z, Novák P, Nagy G. [Clinical importance and diagnosis of halitosis]. Fogorv Sz 2012; 105:105-111. [PMID: 23240492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The origin of halitosis comes from the Latin word "halitus" meaning 'breath, exhaled air', and in the Hungarian terminology it means bad and smelly breath. The human body emits a number of volatile molecules, which have a peculiar odour. Their presence is influenced by several factors, such as genetic, nutritional and psychological factors. Since bad breath belongs to taboo subjects, halitosis can often lead to social isolation. To determine the incidence of halitosis, an exact diagnosis is needed which sometimes predestinates the possible treatment as well. Investigators estimate the incidence about 50% in the whole population. The male/female ratio is the same and the incidence is growing with age. The diagnosis can be genuine halitosis, pseudo halitosis and halitophobia. We can divide the genuine type into physiological and pathophysiological subtypes. The cause of the halitosis usually can be found in the oral cavity. The volatile sulfur compounds (VSC) produced by some of the oral bacteria are responsible for its development. Only 10% of the causes are extraoral, mostly inflammation of airways or gastrointestinal disorders. The judgment of halitosis is based on three objective methods: the organoleptic, the sulphide monitoring and the gas cromatography methods. Since the origin of the halitosis is mainly the oral cavity, dentists should treat them. Beyond the dental treatments the enhancement of the oral hygiene, the continuous motivation and monitoring are also very important, such as the use of tongue cleansing and special anti-malodour rinses.
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Affiliation(s)
- Akos Nagy
- Pécsi Tudományegyetem, Fogászati é Szájsebészeti Klinika
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9
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Lai Y, Chu L. Novel mechanism for conditional aerobic growth of the anaerobic bacterium Treponema denticola. Appl Environ Microbiol 2008; 74:73-9. [PMID: 17981934 PMCID: PMC2223203 DOI: 10.1128/aem.01972-07] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Accepted: 10/25/2007] [Indexed: 01/08/2023] Open
Abstract
Treponema denticola, a periodontal pathogen, has recently been shown to exhibit properties of a facultative anaerobic spirochete, in contrast to its previous recognition as an obligate anaerobic bacterium. In this study, the capacity and possible mechanism of T. denticola survival and growth under aerobic conditions were investigated. Factors detrimental to the growth of T. denticola ATCC 33405, such as oxygen concentration and hydrogen sulfide (H(2)S) levels as well as the enzyme activities of gamma-glutamyltransferase, cysteinylglycinase, and cystalysin associated with the cells were monitored. The results demonstrated that T. denticola grew only at deeper levels of broth (>or=3 ml in a 10-ml tube), high inoculation ratios (>or=20% of culture in medium), and short cultivation times (
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Affiliation(s)
- Yanlai Lai
- Department of Orthodontics, University of Texas Health Science Center, San Antonio, TX 78229, USA
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10
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Magalhães MAO, Sun CX, Glogauer M, Ellen RP. The major outer sheath protein of Treponema denticola selectively inhibits Rac1 activation in murine neutrophils. Cell Microbiol 2007; 10:344-54. [PMID: 17868382 DOI: 10.1111/j.1462-5822.2007.01045.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Treponema denticola major outer sheath protein (Msp) inhibits neutrophil chemotaxis in vitro, but key regulatory mechanisms have not been identified. Because the Rac small GTPases regulate directional migration in response to chemoattractants, the objective was to analyse the effects of Msp on formyl-methionyl-leucyl-phenylalanine (fMLP)-mediated neutrophil polarization and Rac activation in murine neutrophils. Msp pretreatment of neutrophils inhibited both polarization and chemotactic migration in response to fMLP. Activation of small GTPases was measured by p21 binding domain (PBD) pulldown assays, followed by Western analysis, using monoclonal anti-Rac1, anti-Rac2, anti-cdc42 and anti-RhoA antibodies. Enriched native Msp selectively inhibited fMLP-stimulated Rac1 activation in a concentration-dependent manner, but did not affect Rac2, cdc42 or RhoA activation. Murine neutrophils transfected with vectors expressing fluorescent probes PAK-PBD-YFP and PH-AKT-RFP were used to determine the effects of Msp on the localization of activated Rac and PI3 kinase products. Real-time confocal images showed that Msp inhibited the polarized accumulation of activated Rac and PI3-kinase products upon exposure to fMLP. The findings indicate that T. denticola Msp inhibition of neutrophil polarity may be due to the selective suppression of the Rac1 pathway.
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Affiliation(s)
- Marco A O Magalhães
- CIHR Group in Matrix Dynamics and Dental Research Institute, University of Toronto, Faculty of Dentistry, Toronto, Ontario, Canada
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11
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Abstract
Treponema denticola, a periodontal pathogen, is relatively resistant to human beta-defensins, which are small cationic antimicrobial peptides produced by a number of cells, including the gingival epithelium. Using two independent methods, we previously demonstrated that T. denticola proteases are not responsible for decreased vulnerability to defensins. In this study, we confirmed that the major outer membrane protease, dentilisin, is not responsible for T. denticola insensitivity to defensins and examined several other possible mechanisms, including reduced binding to the bacterial surface and efflux pump activity. It has been suggested that some bacteria mask their surfaces with serum proteins. T. denticola grown in a serum-free medium did not exhibit increased susceptibility to human beta-defensin 2 and 3 (hbetaD-2 and hbetaD-3, respectively), suggesting that cloaking of the outer surface with host proteins is not involved in defensin resistance. Nonetheless, we demonstrated that T. denticola binds significantly less hbetaD-2 and -3 than susceptible organisms bind, suggesting that the unusual outer membrane composition of T. denticola may discourage cationic peptide binding. Efflux pumps have been shown to mediate resistance to antibiotics and cationic peptides in other bacteria, and their role in T. denticola's relative resistance to beta-defensins was investigated. Three inhibitors of bacterial ATP-binding cassette (ABC) efflux pumps had no effect on T. denticola's susceptibility to hbetaD-2 or -3. In contrast, a proton motive force inhibitor, carbonyl cyanide 3-chlorophenylhydrazone, increased the susceptibility of T. denticola to killing by hbetaD-3, demonstrating a potential role for efflux pumps (other than ABC pumps) in resistance to this peptide. Our data suggest that the combination of decreased defensin binding and efflux of any peptide which enters the cytoplasm may explain T. denticola's relative resistance to human beta-defensins.
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Affiliation(s)
- Catherine A Brissette
- Department of Pathobiology, University of Washington, Seattle, Washington 98195, USA
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12
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Abstract
The aim was to investigate whether reference cultures and fresh isolates of Treponema denticola are able to 5alpha-reduce and further metabolise testosterone, 4-androstenedione, progesterone, corticosterone, cortisol or cholesterol. Two reference and five freshly isolated cultures of T. denticola were incubated with either radiolabeled or unlabeled steroid substrates; in the first case products were identified by thin layer chromatography and in the latter by gas chromatography-mass spectroscopy. All the substrates were 5alpha-reduced. Both reference cultures and fresh isolates of T. denticola presented 3beta- and 17beta-hydroxy steroid dehydrogenase activity. It was concluded that T. denticola was capable of steroid metabolism and hypotheses are discussed regarding the in vivo function of this metabolism including, T. denticola utilising host supplied steroids as growth factors and T. denticola steroid metabolism acting as a virulence factor.
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Affiliation(s)
- Douglas T Clark
- Department of Microbiology, King's College London Dental Institute at Guy's, King's College and St. Thomas' Hospitals, UK.
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13
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McDowell JV, Lankford J, Stamm L, Sadlon T, Gordon DL, Marconi RT. Demonstration of factor H-like protein 1 binding to Treponema denticola, a pathogen associated with periodontal disease in humans. Infect Immun 2005; 73:7126-32. [PMID: 16239506 PMCID: PMC1273895 DOI: 10.1128/iai.73.11.7126-7132.2005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Treponema denticola is an important contributor to periodontal disease. In this study we investigated the ability of T. denticola to bind the complement regulatory proteins factor H and factor H-like protein 1 (FHL-1). The binding of these proteins has been demonstrated to facilitate evasion of the alternative complement cascade and/or to play a role in adherence and invasion. Here we demonstrate that T. denticola specifically binds FHL-1 via a 14-kDa, surface-exposed protein that we designated FhbB. Consistent with its FHL-1 binding specificity, FhbB binds only to factor H recombinant fragments spanning short consensus repeats (SCRs) 1 to 7 (H7 construct) and not to SCR constructs spanning SCRs 8 to 15 and 16 to 20. Binding of H7 to FhbB was inhibited by heparin. The specific involvement of SCR 7 in the interaction was demonstrated using an H7 mutant (H7AB) in which specific charged residues in SCR 7 were replaced by alanine. This construct lost FhbB binding ability. Analyses of the ability of FHL-1 bound to the surface of T. denticola to serve as a cofactor for factor I-mediated cleavage of C3b revealed that C3b is cleaved in an FHL-1/factor I-independent manner, perhaps by an unidentified protease. Based on the data presented here, we hypothesize that the primary function of FHL-1 binding by T. denticola might be to facilitate adherence to FHL-1 present on anchorage-dependent cells and in the extracellular matrix.
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Affiliation(s)
- John V McDowell
- Department of Microbiology and Immunology, P.O. Box 980678, Richmond, VA 23298-0678, USA
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Edwards AM, Jenkinson HF, Woodward MJ, Dymock D. Binding properties and adhesion-mediating regions of the major sheath protein of Treponema denticola ATCC 35405. Infect Immun 2005; 73:2891-8. [PMID: 15845495 PMCID: PMC1087326 DOI: 10.1128/iai.73.5.2891-2898.2005] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There is growing evidence that a number of oral Treponema species, in particular Treponema denticola, are associated with the progression of human periodontal disease. The major sheath (or surface) protein (Msp) of T. denticola is implicated in adhesion of bacteria to host cells and tissue proteins and is likely to be an important virulence factor. However, the binding regions of the Msp are not known. We have purified from Escherichia coli recombinant Msp (rMsp) polypeptides corresponding to the following: full-length Msp (rMsp) minus 13 N-terminal amino acid (aa) residues, an amino-terminal fragment (rN-Msp, 189 aa residues), a 57-aa residue segment from the central region (rV-Msp), and a C-terminal fragment (rC-Msp, 272 aa residues). rMsp (530 aa residues) bound to immobilized fibronectin, keratin, laminin, collagen type I, fibrinogen, hyaluronic acid, and heparin. The N- and V-region polypeptides, but not rC-Msp, also bound to these substrates. Binding of rMsp to fibronectin was targeted to the N-terminal heparin I/fibrin I domain. Antibodies to the N-region or V-region polypeptides, but not antibodies to the rC-Msp fragment, blocked adhesion of T. denticola ATCC 35405 cells to a range of host protein molecules. These results suggest that the N-terminal half of Msp carries epitopes that are surface exposed and that are involved in mediating adhesion. Binding of rMsp onto the cell surface of low-level fibronectin-binding Treponema isolates conferred a 10-fold increase in fibronectin binding. This confirms that Msp functions autonomously as an adhesin and raises the possibility that phenotypic complementation of virulence functions might occur within mixed populations of Treponema species.
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Affiliation(s)
- Andrew M Edwards
- Oral Microbiology Unit, Department of Oral and Dental Science, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, United Kingdom.
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Bian XL, Wang HT, Ning Y, Lee SY, Fenno JC. Mutagenesis of a novel gene in the prcA-prtP protease locus affects expression of Treponema denticola membrane complexes. Infect Immun 2005; 73:1252-5. [PMID: 15664975 PMCID: PMC547024 DOI: 10.1128/iai.73.2.1252-1255.2005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel gene was identified in the Treponema denticola prcA-prtP protease operon. Strains with mutations in either the prcA-prtP or the msp region showed altered expression of a product(s) of the other locus. Together, these results provide information on the assembly of outer membrane complexes involved in T. denticola interaction with host cells and tissue.
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Affiliation(s)
- Xue-Lin Bian
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109-1078, USA
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Kato H, Yoshida A, Awano S, Ansai T, Takehara T. Quantitative detection of volatile sulfur compound- producing microorganisms in oral specimens using real-time PCR. Oral Dis 2005; 11 Suppl 1:67-71. [PMID: 15752104 DOI: 10.1111/j.1601-0825.2005.01096.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE It is well-known that some periodontopathic bacteria, especially Porphyromonas gingivalis, Fusobacterium nucleatum, Tannerella forsythia (formerly Bacteroides forsythus or Tan. forsythensis), and Treponema denticola, actively produce volatile sulfur compounds (VSCs), such as H2S and CH3SH. We previously reported a qualitative relationship between periodontopathic bacteria and VSCs; however, a quantitative analysis of periodontopathic bacteria in oral specimens is required for further characterization of the relationship between oral bacteria and VSCs. In this study, we report a real-time polymerase chain reaction (PCR) method for the quantitative analysis of VSC-producing bacteria in oral specimens. SUBJECTS AND METHODS Specimens were collected from 22 patients who visited the Preventive Dentistry and Breath Odor Clinic of Kyushu Dental College. A real-time PCR assay using the TaqMan system, based on the 5'-3' exonuclease activity of Taq polymerase, was employed for the quantitative analysis of periodontopathic bacteria that produce VSCs. RESULTS Using real-time PCR, we performed a quantitative analysis of P. gingivalis, F. nucleatum, Tan. forsythia, and T. denticola in the saliva, on the tongue coat, and in the subgingival plaque of patients with oral malodor. CONCLUSION Real-time PCR using the TaqMan system can be used for the quantitative analysis of VSC-producing oral bacteria.
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Affiliation(s)
- H Kato
- Department of Preventive Dentistry, Kyushu Dental College, Kitakyushu, Japan.
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