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Ciccotosto GD, Mohammed AI, Paolini R, Bijlsma E, Toulson S, Holden J, Reynolds EC, Dashper SG, Butler CA. Chronic Oral Inoculation of Porphyromonas gingivalis and Treponema denticola Induce Different Brain Pathologies in a Mouse Model of Alzheimer Disease. J Infect Dis 2024; 230:S109-S116. [PMID: 39255392 DOI: 10.1093/infdis/jiae286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2024] Open
Abstract
Periodontitis is a chronic inflammatory disease driven by dysbiosis in subgingival microbial communities leading to increased abundance of a limited number of pathobionts, including Porphyromonas gingivalis and Treponema denticola. Oral health, particularly periodontitis, is a modifiable risk factor for Alzheimer disease (AD) pathogenesis, with components of both these bacteria identified in postmortem brains of persons with AD. Repeated oral inoculation of mice with P. gingivalis results in brain infiltration of bacterial products, increased inflammation, and induction of AD-like biomarkers. P. gingivalis displays synergistic virulence with T. denticola during periodontitis. The aim of the current study was to determine the ability of P. gingivalis and T. denticola, grown in physiologically relevant conditions, individually and in combination, to induce AD-like pathology following chronic oral inoculation of female mice over 12 weeks. P. gingivalis alone significantly increased all 7 brain pathologies examined: neuronal damage, activation of astrocytes and microglia, expression of inflammatory cytokines interleukin 1β (IL-1β) and interleukin 6 and production of amyloid-β plaques and hyperphosphorylated tau, in the hippocampus, cortex and midbrain, compared to control mice. T. denticola alone significantly increased neuronal damage, activation of astrocytes and microglia, and expression of IL-1β, in the hippocampus, cortex and midbrain, compared to control mice. Coinoculation of P. gingivalis with T. denticola significantly increased activation of astrocytes and microglia in the hippocampus, cortex and midbrain, and increased production of hyperphosphorylated tau and IL-1β in the hippocampus only. The host brain response elicited by oral coinoculation was less than that elicited by each bacterium, suggesting coinoculation was less pathogenic.
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Affiliation(s)
| | - Ali I Mohammed
- Melbourne Dental School, The University of Melbourne, Melbourne, Australia
| | - Rita Paolini
- Melbourne Dental School, The University of Melbourne, Melbourne, Australia
| | - Elly Bijlsma
- Melbourne Dental School, The University of Melbourne, Melbourne, Australia
| | - Su Toulson
- Melbourne Dental School, The University of Melbourne, Melbourne, Australia
| | - James Holden
- Melbourne Dental School, The University of Melbourne, Melbourne, Australia
| | - Eric C Reynolds
- Melbourne Dental School, The University of Melbourne, Melbourne, Australia
| | - Stuart G Dashper
- Melbourne Dental School, The University of Melbourne, Melbourne, Australia
| | - Catherine A Butler
- Melbourne Dental School, The University of Melbourne, Melbourne, Australia
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2
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Scott C, Dias AP, De Buck J. Adherence and metal-ion acquisition gene expression increases during infection with Treponema phagedenis strains from bovine digital dermatitis. Infect Immun 2024; 92:e0011724. [PMID: 38940601 PMCID: PMC11320908 DOI: 10.1128/iai.00117-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 05/16/2024] [Indexed: 06/29/2024] Open
Abstract
Digital dermatitis (DD) is an ulcerative foot lesion on the heel bulbs of dairy cattle. DD is a polymicrobial disease with no precise etiology, although Treponema spirochetes are found disproportionally abundant in diseased tissue. Within Treponema, several different species are found in DD; however, the species Treponema phagedenis is uniformly found in copious quantities and deep within the skin layers of the active, ulcerative stages of disease. The pathogenic mechanisms these bacteria use to persist in the skin and the precise role they play in the pathology of DD are widely unknown. To explore the pathogenesis and virulence of Treponema phagedenis, newly isolated strains of this species were investigated in a subcutaneous murine abscess model. In the first trial, a dosage study was conducted to compare the pathogenicity of different strains across three different treponemes per inoculum (TPI) doses based on abscess volumes. In the second trial, the expression levels of 11 putative virulence genes were obtained to gain insight into their involvement in pathogenesis. During the RT-qPCR analysis, it was determined that genes encoding for two metal-ion import lipoproteins and two adherence genes were found highly upregulated during infection. Conversely, two genes involved in motility and chemotaxis were found to not be significantly upregulated or utilized during infection. These results were supported by gene expression data from natural M2 lesions of dairy cattle. This gene expression analysis could highlight the preference in strategy for T. phagedenis to persist and adhere in the host rather than engage in motility and disseminate.
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Affiliation(s)
- Colton Scott
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Angelica P. Dias
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jeroen De Buck
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
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3
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Pisani F, Pisani V, Arcangeli F, Harding A, Singhrao SK. Treponema denticola Has the Potential to Cause Neurodegeneration in the Midbrain via the Periodontal Route of Infection-Narrative Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:6049. [PMID: 37297653 PMCID: PMC10252855 DOI: 10.3390/ijerph20116049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 03/30/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease and the most common example of dementia. The neuropathological features of AD are the abnormal deposition of extracellular amyloid-β (Aβ) and intraneuronal neurofibrillary tangles with hyperphosphorylated tau protein. It is recognized that AD starts in the frontal cerebral cortex, and then it progresses to the entorhinal cortex, the hippocampus, and the rest of the brain. However, some studies on animals suggest that AD could also progress in the reverse order starting from the midbrain and then spreading to the frontal cortex. Spirochetes are neurotrophic: From a peripheral route of infection, they can reach the brain via the midbrain. Their direct and indirect effect via the interaction of their virulence factors and the microglia potentially leads to the host peripheral nerve, the midbrain (especially the locus coeruleus), and cortical damage. On this basis, this review aims to discuss the hypothesis of the ability of Treponema denticola to damage the peripheral axons in the periodontal ligament, to evade the complemental pathway and microglial immune response, to determine the cytoskeletal impairment and therefore causing the axonal transport disruption, an altered mitochondrial migration and the consequent neuronal apoptosis. Further insights about the central neurodegeneration mechanism and Treponema denticola's resistance to the immune response when aggregated in biofilm and its quorum sensing are suggested as a pathogenetic model for the advanced stages of AD.
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Affiliation(s)
- Flavio Pisani
- Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
| | - Valerio Pisani
- IRCCS, “Santa Lucia” Foundation, Neurology and Neurorehabilitation Unit, Via Ardeatina, 306, 00179 Rome, Italy
| | - Francesca Arcangeli
- Azienda Sanitaria Locale ASLRM1, Nuovo Regina Margherita Hospital, Geriatric Department, Advanced Centre for Dementia and Cognitive Disorders, Via Emilio Morosini, 30, 00153 Rome, Italy
| | - Alice Harding
- Dementia and Neurodegenerative Disease Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
| | - Simarjit Kaur Singhrao
- Dementia and Neurodegenerative Disease Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
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Jiang Q, Zhao Y, Shui Y, Zhou X, Cheng L, Ren B, Chen Z, Li M. Interactions Between Neutrophils and Periodontal Pathogens in Late-Onset Periodontitis. Front Cell Infect Microbiol 2021; 11:627328. [PMID: 33777839 PMCID: PMC7994856 DOI: 10.3389/fcimb.2021.627328] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 02/03/2021] [Indexed: 02/05/2023] Open
Abstract
Late-onset periodontitis is associated with a series of inflammatory reactions induced by periodontal pathogens, such as Porphyromonas gingivalis, a keystone pathogen involved in periodontitis. Neutrophils are the most abundant leukocytes in the periodontal pocket/gingival crevice and inflamed periodontal tissues. They form a “wall” between the dental plaque and the junctional epithelium, preventing microbial invasion. The balance between neutrophils and the microbial community is essential to periodontal homeostasis. Excessive activation of neutrophils in response to periodontal pathogens can induce tissue damage and lead to periodontitis persistence. Therefore, illuminating the interactions between neutrophils and periodontal pathogens is critical for progress in the field of periodontitis. The present review aimed to summarize the interactions between neutrophils and periodontal pathogens in late-onset periodontitis, including neutrophil recruitment, neutrophil mechanisms to clear the pathogens, and pathogen strategies to evade neutrophil-mediated elimination of bacteria. The recruitment is a multi-step process, including tethering and rolling, adhesion, crawling, and transmigration. Neutrophils clear the pathogens mainly by phagocytosis, respiratory burst responses, degranulation, and neutrophil extracellular trap (NET) formation. The mechanisms that pathogens activate to evade neutrophil-mediated killing include impairing neutrophil recruitment, preventing phagocytosis, uncoupling killing from inflammation, and resistance to ROS, degranulation products, and NETs.
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Affiliation(s)
- Qingsong Jiang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
| | - Yuxi Zhao
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
| | - Yusen Shui
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
| | - Lei Cheng
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
| | - Biao Ren
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
| | - Zhu Chen
- Department of Conservative Dentistry and Endodontics, Guiyang Hospital of Stomatology, Guiyang, China
| | - Mingyun Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
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5
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Montaño-Rendón F, Grinstein S, Walpole GFW. Monitoring Phosphoinositide Fluxes and Effectors During Leukocyte Chemotaxis and Phagocytosis. Front Cell Dev Biol 2021; 9:626136. [PMID: 33614656 PMCID: PMC7890364 DOI: 10.3389/fcell.2021.626136] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 01/06/2021] [Indexed: 01/22/2023] Open
Abstract
The dynamic re-organization of cellular membranes in response to extracellular stimuli is fundamental to the cell physiology of myeloid and lymphoid cells of the immune system. In addition to maintaining cellular homeostatic functions, remodeling of the plasmalemma and endomembranes endow leukocytes with the potential to relay extracellular signals across their biological membranes to promote rolling adhesion and diapedesis, migration into the tissue parenchyma, and to ingest foreign particles and effete cells. Phosphoinositides, signaling lipids that control the interface of biological membranes with the external environment, are pivotal to this wealth of functions. Here, we highlight the complex metabolic transitions that occur to phosphoinositides during several stages of the leukocyte lifecycle, namely diapedesis, migration, and phagocytosis. We describe classical and recently developed tools that have aided our understanding of these complex lipids. Finally, major downstream effectors of inositides are highlighted including the cytoskeleton, emphasizing the importance of these rare lipids in immunity and disease.
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Affiliation(s)
- Fernando Montaño-Rendón
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
| | - Glenn F W Walpole
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
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Miralda I, Uriarte SM. Periodontal Pathogens' strategies disarm neutrophils to promote dysregulated inflammation. Mol Oral Microbiol 2020; 36:103-120. [PMID: 33128827 PMCID: PMC8048607 DOI: 10.1111/omi.12321] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 10/16/2020] [Accepted: 10/28/2020] [Indexed: 12/26/2022]
Abstract
Periodontitis is an irreversible, chronic inflammatory disease where inflammophilic pathogenic microbial communities accumulate in the gingival crevice. Neutrophils are a major component of the innate host response against bacterial challenge, and under homeostatic conditions, their microbicidal functions typically protect the host against periodontitis. However, a number of periodontal pathogens developed survival strategies to evade neutrophil microbicidal functions while promoting inflammation, which provides a source of nutrients for bacterial growth. Research on periodontal pathogens has largely focused on a few established species: Tannerella forsythia, Treponema denticola, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis. However, advances in culture-independent techniques have facilitated the identification of new bacterial species in periodontal lesions, such as the two Gram-positive anaerobes, Filifactor alocis and Peptoanaerobacter stomatis, whose characterization of pathogenic potential has not been fully described. Additionally, there is not a full understanding of the pathogenic mechanisms used against neutrophils by organisms that are abundant in periodontal lesions. This presents a substantial barrier to the development of new approaches to prevent or ameliorate the disease. In this review, we first summarize the neutrophil functions affected by the established periodontal pathogens listed above, denoting unknown areas that still merit a closer look. Then, we review the literature on neutrophil functions and the emerging periodontal pathogens, F. alocis and P. stomatis, comparing the effects of the emerging microbes to that of established pathogens, and speculate on the contribution of these putative pathogens to the progression of periodontal disease.
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Affiliation(s)
- Irina Miralda
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY, USA
| | - Silvia M Uriarte
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY, USA
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The Msp Protein of Treponema denticola Interrupts Activity of Phosphoinositide Processing in Neutrophils. Infect Immun 2019; 87:IAI.00553-19. [PMID: 31481407 DOI: 10.1128/iai.00553-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 08/27/2019] [Indexed: 12/15/2022] Open
Abstract
Periodontal disease is a significant health burden, causing tooth loss and poor oral and overall systemic health. Dysbiosis of the oral biofilm and a dysfunctional immune response drive chronic inflammation, causing destruction of soft tissue and alveolar bone supporting the teeth. Treponema denticola, a spirochete abundant in the plaque biofilm of patients with severe periodontal disease, perturbs neutrophil function by modulating appropriate phosphoinositide (PIP) signaling. Through a series of immunoblotting and quantitative PCR (qPCR) experiments, we show that Msp does not alter the gene transcription or protein content of key enzymes responsible for PIP3 signaling: 3' phosphatase and tensin homolog (PTEN), phosphatidylinositol 3-kinase (PI3K), or 5' Src homology 2 domain-containing inositol phosphatase 1 (SHIP1). Instead, using immunoblotting and enzyme-linked immunosorbent assays (ELISAs), we found that Msp activates PTEN through dephosphorylation specifically at the S380 site. Msp in intact organisms or outer membrane vesicles also restricts PIP signaling. SHIP1 phosphatase release was assessed using chemical inhibition and immunoprecipitation to show that Msp moderately decreases SHIP1 activity. Msp also prevents secondary activation of the PTEN/PI3K response. We speculate that this result is due to the redirection of the PIP3 substrate away from SHIP1 to PTEN. Immunofluorescence microscopy revealed a redistribution of PTEN from the cytoplasm to the plasma membrane following exposure to Msp, which may contribute to PTEN activation. Mechanisms of how T. denticola modulates and evades the host immune response are still poorly described, and here we provide further mechanistic evidence of how spirochetes modify PIP signaling to dampen neutrophil function. Understanding how oral bacteria evade the immune response to perpetuate the cycle of inflammation and infection is critical for combating periodontal disease to improve overall health outcomes.
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8
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The major outer sheath protein forms distinct conformers and multimeric complexes in the outer membrane and periplasm of Treponema denticola. Sci Rep 2017; 7:13260. [PMID: 29038532 PMCID: PMC5643300 DOI: 10.1038/s41598-017-13550-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 09/25/2017] [Indexed: 12/24/2022] Open
Abstract
The major outer sheath protein (MOSP) is a prominent constituent of the cell envelope of Treponema denticola (TDE) and one of its principal virulence determinants. Bioinformatics predicts that MOSP consists of N- and C-terminal domains, MOSPN and MOSPC. Biophysical analysis of constructs refolded in vitro demonstrated that MOSPC, previously shown to possess porin activity, forms amphiphilic trimers, while MOSPN forms an extended hydrophilic monomer. In TDE and E. coli expressing MOSP with a PelB signal sequence (PelB-MOSP), MOSPC is OM-embedded and surface-exposed, while MOSPN resides in the periplasm. Immunofluorescence assay, surface proteolysis, and novel cell fractionation schemes revealed that MOSP in TDE exists as outer membrane (OM) and periplasmic trimeric conformers; PelB-MOSP, in contrast, formed only OM-MOSP trimers. Although both conformers form hetero-oligomeric complexes in TDE, only OM-MOSP associates with dentilisin. Mass spectrometry (MS) indicated that OM-MOSP interacts with proteins in addition to dentilisin, most notably, oligopeptide-binding proteins (OBPs) and the β-barrel of BamA. MS also identified candidate partners for periplasmic MOSP, including TDE1658, a spirochete-specific SurA/PrsA ortholog. Collectively, our data suggest that MOSP destined for the TDE OM follows the canonical BAM pathway, while formation of a stable periplasmic conformer involves an export-related, folding pathway not present in E. coli.
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9
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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] [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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10
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You M, Chan Y, Lacap-Bugler DC, Huo YB, Gao W, Leung WK, Watt RM. Oral treponeme major surface protein: Sequence diversity and distributions within periodontal niches. Mol Oral Microbiol 2017; 32:455-474. [PMID: 28453906 DOI: 10.1111/omi.12185] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/24/2017] [Indexed: 12/19/2022]
Abstract
Treponema denticola and other species (phylotypes) of oral spirochetes are widely considered to play important etiological roles in periodontitis and other oral infections. The major surface protein (Msp) of T. denticola is directly implicated in several pathological mechanisms. Here, we have analyzed msp sequence diversity across 68 strains of oral phylogroup 1 and 2 treponemes; including reference strains of T. denticola, Treponema putidum, Treponema medium, 'Treponema vincentii', and 'Treponema sinensis'. All encoded Msp proteins contained highly conserved, taxon-specific signal peptides, and shared a predicted 'three-domain' structure. A clone-based strategy employing 'msp-specific' polymerase chain reaction primers was used to analyze msp gene sequence diversity present in subgingival plaque samples collected from a group of individuals with chronic periodontitis (n=10), vs periodontitis-free controls (n=10). We obtained 626 clinical msp gene sequences, which were assigned to 21 distinct 'clinical msp genotypes' (95% sequence identity cut-off). The most frequently detected clinical msp genotype corresponded to T. denticola ATCC 35405T , but this was not correlated to disease status. UniFrac and libshuff analysis revealed that individuals with periodontitis and periodontitis-free controls harbored significantly different communities of treponeme clinical msp genotypes (P<.001). Patients with periodontitis had higher levels of clinical msp genotype diversity than periodontitis-free controls (Mann-Whitney U-test, P<.05). The relative proportions of 'T. vincentii' clinical msp genotypes were significantly higher in the control group than in the periodontitis group (P=.018). In conclusion, our data clearly show that both healthy and diseased individuals commonly harbor a wide diversity of Treponema clinical msp genotypes within their subgingival niches.
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Affiliation(s)
- M You
- Department of Oral Radiology and State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, Chengdu, China
| | - Y Chan
- Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital, Sai Ying Pun, Hong Kong SAR, China
| | - D C Lacap-Bugler
- School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, New Zealand
| | - Y-B Huo
- Zhujiang New Town Dental Clinic, Guanghua School and Hospital of Stomatology, Guangdong Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - W Gao
- Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital, Sai Ying Pun, Hong Kong SAR, China
| | - W K Leung
- Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital, Sai Ying Pun, Hong Kong SAR, China
| | - R M Watt
- Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital, Sai Ying Pun, Hong Kong SAR, China
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11
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Bloch S, Thurnheer T, Murakami Y, Belibasakis GN, Schäffer C. Behavior of two Tannerella forsythia strains and their cell surface mutants in multispecies oral biofilms. Mol Oral Microbiol 2017; 32:404-418. [PMID: 28382776 PMCID: PMC5600126 DOI: 10.1111/omi.12182] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/28/2017] [Indexed: 12/16/2022]
Abstract
As a member of subgingival multispecies biofilms, Tannerella forsythia is commonly associated with periodontitis. The bacterium has a characteristic cell surface (S‐) layer modified with a unique O‐glycan. Both the S‐layer and the O‐glycan were analyzed in this study for their role in biofilm formation by employing an in vitro multispecies biofilm model mimicking the situation in the oral cavity. Different T. forsythia strains and mutants with characterized defects in cell surface composition were incorporated into the model, together with nine species of select oral bacteria. The influence of the T. forsythia S‐layer and attached glycan on the bacterial composition of the biofilms was analyzed quantitatively using colony‐forming unit counts and quantitative real‐time polymerase chain reaction, as well as qualitatively by fluorescence in situ hybridization and confocal laser scanning microscopy. This revealed that changes in the T. forsythia cell surface did not affect the quantitative composition of the multispecies consortium, with the exception of Campylobacter rectus cell numbers. The localization of T. forsythia within the bacterial agglomeration varied depending on changes in the S‐layer glycan, and this also affected its aggregation with Porphyromonas gingivalis. This suggests a selective role for the glycosylated T. forsythia S‐layer in the positioning of this species within the biofilm, its co‐localization with P. gingivalis, and the prevalence of C. rectus. These findings might translate into a potential role of T. forsythia cell surface structures in the virulence of this species when interacting with host tissues and the immune system, from within or beyond the biofilm.
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Affiliation(s)
- Susanne Bloch
- Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Vienna, Vienna, Austria
| | - Thomas Thurnheer
- Division of Oral Microbiology and Immunology, Institute of Oral Biology, Center of Dental Medicine, University of Zürich, Zürich, Switzerland
| | - Yukitaka Murakami
- Department of Oral Microbiology, Asahi University School of Dentistry, Mizuho, Gifu, Japan
| | - Georgios N Belibasakis
- Division of Cariology and Endodontics, Department of Dental Medicine, Karolinska Institute, Huddinge, Sweden
| | - Christina Schäffer
- Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Vienna, Vienna, Austria
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12
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Uriarte SM, Edmisson JS, Jimenez-Flores E. Human neutrophils and oral microbiota: a constant tug-of-war between a harmonious and a discordant coexistence. Immunol Rev 2016; 273:282-98. [PMID: 27558341 PMCID: PMC5353849 DOI: 10.1111/imr.12451] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neutrophils are a major component of the innate host response, and the outcome of the interaction between the oral microbiota and neutrophils is a key determinant of oral health status. The composition of the oral microbiome is very complex and different in health and disease. Neutrophils are constantly recruited to the oral cavity, and their protective role is highlighted in cases where their number or functional responses are impeded, resulting in different forms of periodontal disease. Periodontitis, one of the more severe and irreversible forms of periodontal disease, is a microbial-induced chronic inflammatory disease that affects the gingival tissues supporting the tooth. This chronic inflammatory disease is the result of a shift of the oral bacterial symbiotic community to a dysbiotic more complex community. Chronic inflammatory infectious diseases such as periodontitis can occur because the pathogens are able to evade or disable the innate immune system. In this review, we discuss how human neutrophils interact with both the symbiotic and the dysbiotic oral community; an understanding of which is essential to increase our knowledge of the periodontal disease process.
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Affiliation(s)
- Silvia M. Uriarte
- Department of Medicine, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Jacob S. Edmisson
- Department of Biology, School of Arts & Sciences, University of Louisville, Louisville, KY, USA
| | - Emeri Jimenez-Flores
- Department of Oral Immunology and Infectious Diseases, Schoaol of Dentistry, University of Louisville, Louisville, KY, USA
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Inagaki S, Kimizuka R, Kokubu E, Saito A, Ishihara K. Treponema denticola invasion into human gingival epithelial cells. Microb Pathog 2016; 94:104-11. [PMID: 26806000 DOI: 10.1016/j.micpath.2016.01.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 01/08/2016] [Accepted: 01/12/2016] [Indexed: 02/06/2023]
Abstract
Host cell invasion is important for periodontal pathogens in evading host defenses and spreading into deeper areas of the periodontal tissue. Treponema denticola has been implicated in a number of potentially pathogenic processes, including periodontal tissue penetration. Here we tested the ability of T. denticola strains to invade human gingival epithelial cells (HGEC). After 2 h infection, intracellular location of T. denticola cells was confirmed by confocal laser scanning microscopy (CLSM). Results from an antibiotic protection assay following [(3)H]uridine labeling indicated that invasion efficiency reached a maximum at 2 h after infection. Internalized T. denticola cells were still observed in HGEC at 24 h by CLSM. A dentilisin deficient mutant exhibited significantly decreased invasion (p < 0.05) compared with the wild-type strain. In inhibition assays, phenylmethylsulfonyl fluoride and metabolic inhibitors such as methyl-β-cyclodextrin and staurosporine significantly reduced T. denticola invasion. Under CLSM, T. denticola colocalized with GM-1 ganglioside-containing membrane microdomains in a cholesterol-dependent manner. These results indicated that T. denticola has the ability to invade into and survive within HGECs. Dentilisin activity of T. denticola and lipid rafts on HGEC appear to play important roles in this process.
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Affiliation(s)
- Satoru Inagaki
- Oral Health Science Center, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-0064, Japan; Department of Microbiology, Tokyo Dental College, 2-1-14 Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan
| | - Ryuta Kimizuka
- Oral Health Science Center, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-0064, Japan; Department of Microbiology, Tokyo Dental College, 2-1-14 Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan
| | - Eitoyo Kokubu
- Oral Health Science Center, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-0064, Japan; Department of Microbiology, Tokyo Dental College, 2-1-14 Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan
| | - Atsushi Saito
- Oral Health Science Center, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-0064, Japan; Department of Periodontology, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan
| | - Kazuyuki Ishihara
- Oral Health Science Center, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-0064, Japan; Department of Microbiology, Tokyo Dental College, 2-1-14 Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan.
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Visser MB, Sun CX, Koh A, Ellen RP, Glogauer M. Treponema denticola major outer sheath protein impairs the cellular phosphoinositide balance that regulates neutrophil chemotaxis. PLoS One 2013; 8:e66209. [PMID: 23755300 PMCID: PMC3670873 DOI: 10.1371/journal.pone.0066209] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 05/06/2013] [Indexed: 12/16/2022] Open
Abstract
The major outer sheath protein (Msp) of Treponema denticola inhibits neutrophil polarization and directed chemotaxis together with actin dynamics in vitro in response to the chemoattractant N-formyl-methionine-leucine-phenylanine (fMLP). Msp disorients chemotaxis through inhibition of a Rac1-dependent signaling pathway, but the upstream mechanisms are unknown. We challenged murine bone marrow neutrophils with enriched native Msp to determine the role of phospholipid modifying enzymes in chemotaxis and actin assembly downstream of fMLP-stimulation. Msp modulated cellular phosphoinositide levels through inhibition of phosphatidylinositol 3-kinase (PI3-kinase) together with activation of the lipid phosphatase, phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Impaired phosphatidylinositol[(3,4,5)]-triphosphate (PIP3) levels prevented recruitment and activation of the downstream mediator Akt. Release of the actin capping proteins gelsolin and CapZ in response to fMLP was also inhibited by Msp exposure. Chemical inhibition of PTEN restored PIP3 signaling, as measured by Akt activation, Rac1 activation, actin uncapping, neutrophil polarization and chemotaxis in response to fMLP-stimulation, even in the presence of Msp. Transduction with active Rac1 also restored fMLP-mediated actin uncapping, suggesting that Msp acts at the level of PIP3 in the hierarchical feedback loop of PIP3 and Rac1 activation. Taken together, Msp alters the phosphoinositide balance in neutrophils, impairing the cell “compass”, which leads to inhibition of downstream chemotactic events.
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Affiliation(s)
- Michelle B Visser
- Matrix Dynamics Group, Dental Research Institute, University of Toronto, Toronto, Ontario, Canada.
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15
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The major outer sheath protein (Msp) of Treponema denticola has a bipartite domain architecture and exists as periplasmic and outer membrane-spanning conformers. J Bacteriol 2013; 195:2060-71. [PMID: 23457251 DOI: 10.1128/jb.00078-13] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The major outer sheath protein (Msp) is a primary virulence determinant in Treponema denticola, as well as the parental ortholog for the Treponema pallidum repeat (Tpr) family in the syphilis spirochete. The Conserved Domain Database (CDD) server revealed that Msp contains two conserved domains, major outer sheath protein(N) (MOSP(N)) and MOSP(C), spanning residues 77 to 286 and 332 to 543, respectively, within the N- and C-terminal regions of the protein. Circular dichroism (CD) spectroscopy, Triton X-114 (TX-114) phase partitioning, and liposome incorporation demonstrated that full-length, recombinant Msp (Msp(Fl)) and a recombinant protein containing MOSP(C), but not MOSP(N), form amphiphilic, β-sheet-rich structures with channel-forming activity. Immunofluorescence analysis of intact T. denticola revealed that only MOSP(C) contains surface-exposed epitopes. Data obtained using proteinase K accessibility, TX-114 phase partitioning, and cell fractionation revealed that Msp exists as distinct OM-integrated and periplasmic trimers. Msp(Fl) folded in Tris buffer contained slightly less β-sheet structure than detergent-folded Msp(Fl); both forms, however, partitioned into the TX-114 detergent-enriched phase. CDD analysis of the nine Tpr paralogs predicted to be outer membrane proteins (OMPs) revealed that seven have an Msp-like bipartite structure; phylogenetic analysis revealed that the MOSP(N) and MOSP(C) domains of Msp are most closely related to those of TprK. Based upon our collective results, we propose a model whereby a newly exported, partially folded intermediate can be either processed for OM insertion by the β-barrel assembly machinery (BAM) or remain periplasmic, ultimately forming a stable, water-soluble trimer. Extrapolated to T. pallidum, our model enables us to explain how individual Tprs can localize to either the periplasmic (e.g., TprK) or OM (e.g., TprC) compartments.
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16
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Possible translocation of periodontal pathogens into the lymph nodes draining the oral cavity. J Microbiol 2012; 50:827-36. [PMID: 23124752 DOI: 10.1007/s12275-012-2030-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 06/19/2012] [Indexed: 01/03/2023]
Abstract
Numerous publications have reported the presence of periodontopathogenic bacteria in peripheral and central vascular lesions. However, it is unclear how this bacterial translocation occurs. The objective of this study was to investigate whether periodontopathic bacteria are translocated to lymph nodes proximal to the oral cavity. Obtaining lymph node samples is not ethically feasible unless they are excised as part of the surgical management of patients with cancer. This study analyzed formalin-fixed and paraffin-embedded lymph nodes, histologically negative for cancer cell invasion, that were excised from 66 patients with histories of head and neck cancer. Real-time PCR was performed to amplify the 16S ribosomal DNA fragments from Porphyromonas gingivalis, Treponema denticola, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Prevotella intermedia. The relationship between bacterial detection and cancer severity, gender, and the use of anti-cancer therapy was examined by Fisher's exact test. P. gingivalis, T. forsythia, and P. intermedia were present in 17%, 8%, and 8% of the samples of submandibular and submental lymph nodes, respectively. There were no significant relationships between bacterial detection and the cancer disease status, patient gender or use of anticancer therapy. According to these data, it appears that the translocation of periodontopathic bacteria may occur via lymphatic drainage, irrespective of the cancer disease status, gender or anticancer therapy.
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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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18
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Visser MB, Koh A, Glogauer M, Ellen RP. Treponema denticola major outer sheath protein induces actin assembly at free barbed ends by a PIP2-dependent uncapping mechanism in fibroblasts. PLoS One 2011; 6:e23736. [PMID: 21901132 PMCID: PMC3161991 DOI: 10.1371/journal.pone.0023736] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 07/22/2011] [Indexed: 01/13/2023] Open
Abstract
The major outer sheath protein (Msp) of Treponema denticola perturbs actin dynamics in fibroblasts by inducing actin reorganization, including subcortical actin filament assembly, leading to defective calcium flux, diminished integrin engagement of collagen, and retarded cell migration. Yet, its mechanisms of action are unknown. We challenged Rat-2 fibroblasts with enriched native Msp. Msp activated the small GTPases Rac1, RhoA and Ras, but not Cdc42, yet only Rac1 localized to areas of actin rearrangement. We used Rac1 dominant negative transfection and chemical inhibition of phosphatidylinositol-3 kinase (PI3K) to show that even though Rac1 activation was PI3K-dependent, neither was required for Msp-induced actin rearrangement. Actin free barbed end formation (FBE) by Msp was also PI3K-independent. Immunoblotting experiments showed that gelsolin and CapZ were released from actin filaments, whereas cofilin remained in an inactive state. Msp induced phosphatidylinositol (4,5)-bisphosphate (PIP2) formation through activation of a phosphoinositide 3-phosphatase and its recruitment to areas of actin assembly at the plasma membrane. Using a PIP2 binding peptide or lipid phosphatase inhibitor, PIP2 was shown to be required for Msp-mediated actin uncapping and FBE formation. Evidently, Msp induces actin assembly in fibroblasts by production and recruitment of PIP2 and release of the capping proteins CapZ and gelsolin from actin barbed ends.
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Affiliation(s)
- Michelle B Visser
- Matrix Dynamics Group, Dental Research Institute, University of Toronto, Toronto, Ontario, Canada.
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19
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Visser M, Ellen R. New insights into the emerging role of oral spirochaetes in periodontal disease. Clin Microbiol Infect 2011; 17:502-12. [DOI: 10.1111/j.1469-0691.2011.03460.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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20
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Martinez-Lopez DG, Fahey M, Coburn J. Responses of human endothelial cells to pathogenic and non-pathogenic Leptospira species. PLoS Negl Trop Dis 2010; 4:e918. [PMID: 21179504 PMCID: PMC3001904 DOI: 10.1371/journal.pntd.0000918] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Accepted: 11/16/2010] [Indexed: 01/11/2023] Open
Abstract
Leptospirosis is a widespread zoonotic infection that primarily affects residents of tropical regions, but causes infections in animals and humans in temperate regions as well. The agents of leptospirosis comprise several members of the genus Leptospira, which also includes non-pathogenic, saprophytic species. Leptospirosis can vary in severity from a mild, non-specific illness to severe disease that includes multi-organ failure and widespread endothelial damage and hemorrhage. To begin to investigate how pathogenic leptospires affect endothelial cells, we compared the responses of two endothelial cell lines to infection by pathogenic versus non-pathogenic leptospires. Microarray analyses suggested that pathogenic L. interrogans and non-pathogenic L. biflexa triggered changes in expression of genes whose products are involved in cellular architecture and interactions with the matrix, but that the changes were in opposite directions, with infection by L. biflexa primarily predicted to increase or maintain cell layer integrity, while L. interrogans lead primarily to changes predicted to disrupt cell layer integrity. Neither bacterial strain caused necrosis or apoptosis of the cells even after prolonged incubation. The pathogenic L. interrogans, however, did result in significant disruption of endothelial cell layers as assessed by microscopy and the ability of the bacteria to cross the cell layers. This disruption of endothelial layer integrity was abrogated by addition of the endothelial protective drug lisinopril at physiologically relevant concentrations. These results suggest that, through adhesion of L. interrogans to endothelial cells, the bacteria may disrupt endothelial barrier function, promoting dissemination of the bacteria and contributing to severe disease manifestations. In addition, supplementing antibiotic therapy with lisinopril or derivatives with endothelial protective activities may decrease the severity of leptospirosis.
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Affiliation(s)
- Denise G. Martinez-Lopez
- Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Division of Infectious Diseases, Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Mark Fahey
- Division of Infectious Diseases, Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Jenifer Coburn
- Division of Infectious Diseases, Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- * E-mail:
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22
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Transcriptional profiles of Treponema denticola in response to environmental conditions. PLoS One 2010; 5:e13655. [PMID: 21048920 PMCID: PMC2965109 DOI: 10.1371/journal.pone.0013655] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Accepted: 09/27/2010] [Indexed: 11/19/2022] Open
Abstract
The periodontal pathogen T. denticola resides in a stressful environment rife with challenges, the human oral cavity. Knowledge of the stress response capabilities of this invasive spirochete is currently very limited. Whole genome expression profiles in response to different suspected stresses including heat shock, osmotic downshift, oxygen and blood exposure were examined. Most of the genes predicted to encode conserved heat shock proteins (HSPs) were found to be induced under heat and oxygen stress. Several of these HSPs also seem to be important for survival in hypotonic solutions and blood. In addition to HSPs, differential regulation of many genes encoding metabolic proteins, hypothetical proteins, transcriptional regulators and transporters was observed in patterns that could betoken functional associations. In summary, stress responses in T. denticola exhibit many similarities to the corresponding stress responses in other organisms but also employ unique components including the induction of hypothetical proteins.
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Dashper SG, Seers CA, Tan KH, Reynolds EC. Virulence factors of the oral spirochete Treponema denticola. J Dent Res 2010; 90:691-703. [PMID: 20940357 DOI: 10.1177/0022034510385242] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
There is compelling evidence that treponemes are involved in the etiology of several chronic diseases, including chronic periodontitis as well as other forms of periodontal disease. There are interesting parallels with other chronic diseases caused by treponemes that may indicate similar virulence characteristics. Chronic periodontitis is a polymicrobial disease, and recent animal studies indicate that co-infection of Treponema denticola with other periodontal pathogens can enhance alveolar bone resorption. The bacterium has a suite of molecular determinants that could enable it to cause tissue damage and subvert the host immune response. In addition to this, it has several non-classic virulence determinants that enable it to interact with other pathogenic bacteria and the host in ways that are likely to promote disease progression. Recent advances, especially in molecular-based methodologies, have greatly improved our knowledge of this bacterium and its role in disease.
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Affiliation(s)
- S G Dashper
- Cooperative Research Centre for Oral Health, Melbourne Dental School and Bio21 Institute, The University of Melbourne, 720 Swanston Street, Victoria 3010, Australia
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Tanabe SI, Bodet C, Grenier D. Treponema denticola lipooligosaccharide activates gingival fibroblasts and upregulates inflammatory mediator production. J Cell Physiol 2008; 216:727-31. [PMID: 18366071 DOI: 10.1002/jcp.21447] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In response to bacterial challenges, fibroblasts, a major constituent of gingival connective tissue, can produce immunoregulatory cytokines and proteolytic enzymes that may contribute to tissue destruction and the progression of periodontitis, a chronic inflammatory disease affecting tooth-supporting tissues, including alveolar bone. The spirochete Treponema denticola is a major etiological agent of periodontitis and can invade oral tissues. The aim of the present study was to investigate the inflammatory response of gingival fibroblasts to T. denticola lipooligosaccharide (LOS). T. denticola LOS induced significant production of various inflammatory mediators by fibroblasts, including interleukin-6, interleukin-8, monocyte chemoattractant protein 1, nitric oxide, and prostaglandin E(2). In addition, the secretion of matrix metalloproteinase 3, an enzyme active on basement membrane components, was also significantly increased. The response of fibroblasts was dose-dependent and much stronger following a 24 h stimulation period. The expression and/or phosphorylation state of several signaling proteins, including Fos, MKK1, MKK2, MKK3/6, NF-kappaB p50, and NF-kappaB p65, was enhanced following stimulation of fibroblasts with T. denticola LOS. In summary, T. denticola LOS induced an inflammatory response in gingival fibroblasts and may thus contribute to the immunopathogenesis of periodontitis and the progression of the disease.
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Affiliation(s)
- Shin-Ichi Tanabe
- Groupe de Recherche en Ecologie Buccale, Faculté de Médecine Dentaire, Université Laval, Quebec City, Quebec, Canada
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Amin M, Grove DA, Kapus A, Glogauer M, Ellen RP. An actin-stabilizing peptide conjugate deduced from the major outer sheath protein of the bacterium Treponema denticola. ACTA ACUST UNITED AC 2007; 64:662-74. [PMID: 17565753 DOI: 10.1002/cm.20213] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A synthetic peptide conjugated to bovine serum albumin, P34(BSA), based on a 10-mer in the deduced amino acid sequence of the major outer sheath protein of Treponema denticola, was found to stabilize actin filaments of fibroblasts. Pretreatment of cells with P34(BSA) inhibited the actin disruption induced by cytochalasin D and latrunculin B. P34(BSA) was taken up by the cells and localized among actin filaments. P34(BSA) bound actin from fibroblast lysates, and cell exposure to P34(BSA) led to the activation of RhoA, a key regulator of actin filament assembly in fibroblasts. Exposure of fibroblasts to P34(BSA) retarded their migration on a collagen substratum. P34(BSA) also inhibited chemotaxis of murine neutrophils. Our findings with a novel peptide conjugate imply that bacterial proteins known to perturb the cytoskeleton represent a rich source of molecular models upon which to design synthetic reagents for modulating actin-dependent cellular functions.
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Affiliation(s)
- Mohsen Amin
- CIHR Group in Matrix Dynamics and Dental Research Institute, University of Toronto, Toronto, Ontario, Canada
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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] [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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