Invasion of Oral and Aortic Tissues by Oral Spirochete Treponema denticola in ApoE−/−Mice Causally Links Periodontal Disease and Atherosclerosis

ABSTRACTTreponema denticolais a predominantly subgingival oral spirochete closely associated with periodontal disease and has been detected in atherosclerosis. This study was designed to evaluate causative links between periodontal disease induced by chronic oralT. denticolainfection and atherosclerosis in hyperlipidemic ApoE−/−mice. ApoE−/−mice (n= 24) were orally infected withT. denticolaATCC 35404 and were euthanized after 12 and 24 weeks.T. denticolagenomic DNA was detected in oral plaque samples, indicating colonization of the oral cavity. Infection elicited significantly (P= 0.0172) higher IgG antibody levels and enhanced intrabony defects than sham infection.T. denticola-infected mice had higher levels of horizontal alveolar bone resorption than sham-infected mice and an associated significant increase in aortic plaque area (P≤ 0.05). Increased atherosclerotic plaque correlated with reduced serum nitric oxide (NO) levels and increased serum-oxidized low-density lipoprotein (LDL) levels compared to those of sham-infected mice.T. denticolainfection altered the expression of genes known to be involved in atherosclerotic development, including the leukocyte/endothelial cell adhesion gene (Thbs4), the connective tissue growth factor gene (Ctgf), and the selectin-E gene (Sele). Fluorescentin situhybridization (FISH) revealedT. denticolaclusters in both gingival and aortic tissue of infected mice. This is the first study examining the potential causative role of chronicT. denticolaperiodontal infection and vascular atherosclerosisin vivoin hyperlipidemic ApoE−/−mice.T. denticolais closely associated with periodontal disease and the rapid progression of atheroma in ApoE−/−mice. These studies confirm a causal link for active oralT. denticolainfection with both atheroma and periodontal disease.

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The Msp Protein of Treponema denticola Interrupts Activity of Phosphoinositide Processing in Neutrophils

Infection and Immunity ◽

10.1128/iai.00553-19 ◽

2019 ◽

Vol 87 (11) ◽

Cited By ~ 1

Author(s):

Megan M. Jones ◽

Stephen T. Vanyo ◽

Michelle B. Visser

Keyword(s):

Immune Response ◽

Periodontal Disease ◽

Alveolar Bone ◽

Membrane Vesicles ◽

Neutrophil Function ◽

Oral Bacteria ◽

Outer Membrane Vesicles ◽

Treponema Denticola ◽

Content Type ◽

Tensin Homolog

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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TheTreponema denticolaPAS Domain-Containing Histidine Kinase Hpk2 Is a Heme Binding Sensor of Oxygen Levels

Journal of Bacteriology ◽

10.1128/jb.00116-18 ◽

2018 ◽

Vol 200 (18) ◽

Cited By ~ 1

Author(s):

Juni Sarkar ◽

Daniel P. Miller ◽

Lee D. Oliver ◽

Richard T. Marconi

Keyword(s):

Microbial Community ◽

Periodontal Disease ◽

Histidine Kinase ◽

Site Directed Mutagenesis ◽

Directed Mutagenesis ◽

Treponema Denticola ◽

Pas Domain ◽

Adaptive Responses ◽

Content Type

ABSTRACTPeriodontal disease (PD) results from a shift in the composition of the microbial community of the subgingival crevice. As the bacterial population transitions from Gram-positive bacteria to predominantly Gram-negative anaerobes and spirochetes, dramatic changes occur in the physiological and immunological environment at diseased sites.Treponema denticolathrives in periodontal pockets, indicating that it has a unique ability to adapt to changing environmental conditions. Hpk2 (tde1970), a Per-Arnt-Sim motif (PAS) domain-containing histidine kinase (HK), is part of theT. denticolaHpk2-Rrp2 (tde1969) two-component regulatory (TCR) system. This TCR system is growth phase regulated and has been postulated to play a key role in adaptive responses. In this study, we employ predictive structural analyses and site-directed mutagenesis to investigate the functional role of specific amino acid residues located within the Hpk2 PAS domain. Specific substitutions impacted autophosphorylation (AP), phosphotransfer (PT), oligomerization, and hemin binding. The AP, PT, hemin binding, and oligomerization potential of some mutated Hpk2 proteins differed under aerobic versus anaerobic reaction conditions. The data presented here suggest that the regulatory activity of Hpk2 is linked to diatomic gas levels. In a broader sense, this study highlights the importance of studying proteins produced by anaerobes under conditions that approximate the environment in which they thrive.IMPORTANCEPeriodontal disease affects nearly 60% of the global adult population. Its costs to individuals, and to society as a whole, are enormous. As periodontal disease develops, there is a shift in the composition of the oral microbial community. The bacteria that become dominant are able to cause significant damage to the tissues that support the teeth, leading to tooth loss.Treponema denticolais one of the keystone pathogens associated with periodontal disease. An earlier study demonstrated that the Hpk2 and Rrp2 proteins play an important role in adaptive responses. Here, we explore the role of specific Hpk2 amino acids in environmental sensing and function, using structural analyses and site-directed mutagenesis.

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Possible interaction between visfatin, periodontal infection, and other systemic diseases: A brief review of literature

European Journal of Dentistry ◽

10.4103/ejd.ejd_284_16 ◽

2017 ◽

Vol 11 (03) ◽

pp. 407-410 ◽

Cited By ~ 13

Author(s):

Mojtaba Bayani ◽

Mohammad Pourali ◽

Mohammad Keivan

Keyword(s):

Periodontal Disease ◽

Bacterial Infections ◽

Alveolar Bone ◽

Gingival Crevicular Fluid ◽

Systemic Diseases ◽

Hand Search ◽

Periodontal Infection ◽

Etiologic Agents ◽

Visfatin Level ◽

Crevicular Fluid

ABSTRACTGingivitis and periodontitis are common bacterial infections caused by a variety of microorganisms. Despite the microorganisms' roles as etiologic agents, inflammation-induced substances also have crucial parts in the loss of connective tissue and the supporting alveolar bone. Visfatin is a pleiotropic mediator, which acts as growth factor, cytokine, and pre-B-cell colony-enhancing factor. A positive correlation was detected between the serum/plasma levels of visfatin and inflammatory disorders such as diabetes mellitus and cardiovascular disease. In addition, the visfatin level was higher in saliva and the gingival crevicular fluid (GCF) of subjects with periodontal disease. This review defined current, predictable patterns of possible interaction of visfatin with periodontal infection and other systemic diseases, using PubMed and Medline databases searching for articles written in English. Peer-reviewed articles were targeted using the following keywords: “visfatin,” “periodontal disease,” “inflammatory mediator,” and “biomarker.” Available full-text articles were read, and related articles were also scrutinized, while a hand search was also performed. Search was confined to human studies, and articles written in English and published between 1985 and 2016 were selected. It was concluded that periodontal infection and other systemic diseases could be related to the levels of visfatin in GCF, saliva, and serum as a biomarker of these diseases.

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Omega-3 Fatty Acid Effect on Alveolar Bone Loss in Rats

Journal of Dental Research ◽

10.1177/154405910608500713 ◽

2006 ◽

Vol 85 (7) ◽

pp. 648-652 ◽

Cited By ~ 51

Author(s):

L. Kesavalu ◽

B. Vasudevan ◽

B. Raghu ◽

E. Browning ◽

D. Dawson ◽

...

Keyword(s):

Fatty Acid ◽

Bone Resorption ◽

Periodontal Disease ◽

Alveolar Bone ◽

Corn Oil ◽

Elevated Serum ◽

Serum Levels ◽

Omega 3 ◽

Igg Antibody ◽

Inflammatory Reactions

Gingival inflammation and alveolar bone resorption are hallmarks of adult periodontitis, elicited in response to oral micro-organisms such as Porphyromonas gingivalis. We hypothesized that omega (ω)-3 fatty acids (FA) dietary supplementation would modulate inflammatory reactions leading to periodontal disease in infected rats. Rats were fed fish oil (ω-3 FA) or corn oil (n-6 FA) diets for 22 weeks and were infected with P. gingivalis. Rats on the ω-3 FA diet exhibited elevated serum levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), documenting diet-induced changes. PCR analyses demonstrated that rats were orally colonized by P. gingivalis; increased IgG antibody levels substantiated this infection. P. gingivalis-infected rats treated with ω-3 FA had significantly less alveolar bone resorption. These results demonstrated the effectiveness of an ω-3 FA-supplemented diet in modulating alveolar bone resorption following P. gingivalis infection, and supported that ω-3 FA may be a useful adjunct in the treatment of periodontal disease. Abbreviations: PUFA, polyunsaturated fatty acid; EPA, eicosapentanoic acid; DHA, docosahexanoic acid; and PCR, polymerase chain-reaction.

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Mitogen-Activated Protein Kinase 2 Signaling Shapes Macrophage Plasticity in Aggregatibacter actinomycetemcomitans-Induced Bone Loss

Infection and Immunity ◽

10.1128/iai.00552-16 ◽

2016 ◽

Vol 85 (1) ◽

Cited By ~ 5

Author(s):

Bethany A. Herbert ◽

Heidi M. Steinkamp ◽

Matthias Gaestel ◽

Keith L. Kirkwood

Keyword(s):

Protein Kinase ◽

Bone Loss ◽

Periodontal Disease ◽

Alveolar Bone ◽

Aggregatibacter Actinomycetemcomitans ◽

Osteoclast Formation ◽

Mitogen Activated Protein Kinase ◽

Micro Computed Tomography ◽

Content Type ◽

Mitogen Activated Protein

ABSTRACT Aggregatibacter actinomycetemcomitans is associated with aggressive periodontal disease, which is characterized by inflammation-driven alveolar bone loss. A. actinomycetemcomitans activates the p38 mitogen-activated protein kinase (MAPK) and MAPK-activated protein kinase 2 (MK2) stress pathways in macrophages that are involved in host responses. During the inflammatory process in periodontal disease, chemokines are upregulated to promote recruitment of inflammatory cells. The objective of this study was to determine the role of MK2 signaling in chemokine regulation during A. actinomycetemcomitans pathogenesis. Utilizing a murine calvarial model, Mk2 +/+ and Mk2 −/− mice were treated with live A. actinomycetemcomitans bacteria at the midsagittal suture. MK2 positively regulated the following macrophage RNA: Emr1 (F4/80), Itgam (CD11b), Csf1r (M-CSF Receptor), Itgal (CD11a), Tnf, and Nos2. Additionally, RNA analysis revealed that MK2 signaling regulated chemokines CCL3 and CCL4 in murine calvarial tissue. Utilizing the chimeric murine air pouch model, MK2 signaling differentially regulated CCL3 and CCL4 in the hematopoietic and nonhematopoietic compartments. Bone resorption pits in calvaria, observed by micro-computed tomography, and osteoclast formation were decreased in Mk2 −/− mice compared to Mk2 +/+ mice after A. actinomycetemcomitans treatment. In conclusion, these data suggest that MK2 in macrophages contributes to regulation of chemokine signaling during A. actinomycetemcomitans-induced inflammation and bone loss.

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Porphyromonas gingivalisandTreponema denticolaMixed Microbial Infection in a Rat Model of Periodontal Disease

Interdisciplinary Perspectives on Infectious Diseases ◽

10.1155/2010/605125 ◽

2010 ◽

Vol 2010 ◽

pp. 1-10 ◽

Cited By ~ 28

Author(s):

Raj K. Verma ◽

Sunethra Rajapakse ◽

Archana Meka ◽

Clayton Hamrick ◽

Sheela Pola ◽

...

Keyword(s):

Periodontal Disease ◽

Rat Model ◽

Alveolar Bone ◽

Treponema Denticola ◽

Periodontal Pathogens ◽

Microbial Infection ◽

Morphometric Measurements ◽

Th2 Immune Response ◽

Microbial Infections ◽

Antibody Levels

Porphyromonas gingivalisandTreponema denticolaare periodontal pathogens that express virulence factors associated with the pathogenesis of periodontitis. In this paper we tested the hypothesis thatP. gingivalisandT. denticolaare synergistic in terms of virulence; using a model of mixed microbial infection in rats. Groups of rats were orally infected with eitherP. gingivalisorT. denticolaor mixed microbial infections for 7 and 12 weeks.P. gingivalisgenomic DNA was detected more frequently by PCR thanT. denticola. Both bacteria induced significantly high IgG, IgG2b, IgG1, IgG2a antibody levels indicating a stimulation of Th1 and Th2 immune response. Radiographic and morphometric measurements demonstrated that rats infected with the mixed infection exhibited significantly more alveolar bone loss than shaminfected control rats. Histology revealed apical migration of junctional epithelium, rete ridge elongation, and crestal alveolar bone resorption; resembling periodontal disease lesion. These results showed thatP. gingivalisandT. denticolaexhibit no synergistic virulence in a rat model of periodontal disease.

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Detection of oral spirochete (Treponema denticola) by modified Fontana staining technique from sub-gingival plaques of patients suffering from periodontal disease and to analyse the morphology of spirochetes with respect to the disease’s status

International Journal of Scientific Reports ◽

10.18203/issn.2454-2156.intjscirep20203110 ◽

2020 ◽

Vol 6 (8) ◽

pp. 286

Author(s):

Sunil Paudel ◽

Jyoti M. Nagamoti ◽

Ved Prakash Mishra ◽

Suraj Twanabasu ◽

Susan Kusma

Keyword(s):

Periodontal Disease ◽

Screening Method ◽

Staining Technique ◽

Laboratory Diagnosis ◽

Global Scale ◽

Personal Hygiene ◽

Treponema Denticola ◽

Periodontal Pathogens ◽

Periodontal Tissues ◽

Periodontal Infection

Background: Infections pertaining to mankind particularly those affecting the periodontal tissues are of serious concerns worldwide and are increasing on a global scale particularly in the tropical and subtropical countries like India. The clinical presentation, though very typical of periodontal infection, is often confused with other oral infection, making laboratory diagnosis and confirmation necessary. The management of periodontal infections needs personal hygiene, awareness of infection, proper diagnosis and medication. The present study was undertaken to demonstrate the oral spirochete (Treponema denticola) from periodontal pathogens suffering from periodontal disease.Methods: A total of 55 clinically diagnosed selected patients of periodontal infection attending the outpatient Department of Periodontics, V. K. Institute of Dental Science, KLE University, Belgaum were studied. Dental plaque was taken as specimens from the patients were processed by modified Fontana staining and observed in microscope. Results: A total number of 55 plaque samples were stained by modified Fontana staining technique. 30 cases were positive and 25 cases were negative. Males were affected more as compared to the females and the age group ranging from 15 to 65. Farmers were more affected compared to other occupation.Conclusions: Microscopic method by modified silver nitrate staining can be a very useful screening method for evaluation of oral spirochetes in a clinical setting if used judiciously keeping in mind the variables that can affect the results.

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Treponema denticola dentilisin triggered TLR2/MyD88 activation upregulates a tissue destructive program involving MMPs via Sp1 in human oral cells

PLoS Pathogens ◽

10.1371/journal.ppat.1009311 ◽

2021 ◽

Vol 17 (7) ◽

pp. e1009311

Author(s):

Sean Ganther ◽

Allan Radaic ◽

Erin Malone ◽

Pachiyappan Kamarajan ◽

Nai-Yuan Nicholas Chang ◽

...

Keyword(s):

Periodontal Disease ◽

Alveolar Bone ◽

Nuclear Translocation ◽

Inflammatory Responses ◽

Oral Microbiome ◽

Oral Disease ◽

Periodontal Ligament Cells ◽

Treponema Denticola ◽

Host Immune Responses

Periodontal disease is driven by dysbiosis in the oral microbiome, resulting in over-representation of species that induce the release of pro-inflammatory cytokines, chemokines, and tissue-remodeling matrix metalloproteinases (MMPs) in the periodontium. These chronic tissue-destructive inflammatory responses result in gradual loss of tooth-supporting alveolar bone. The oral spirochete Treponema denticola (T. denticola), is consistently found at significantly elevated levels in periodontal lesions. Host-expressed Toll-Like Receptor 2 (TLR2) senses a variety of bacterial ligands, including acylated lipopolysaccharides and lipoproteins. T. denticola dentilisin, a surface-expressed protease complex comprised of three lipoproteins has been implicated as a virulence factor in periodontal disease, primarily due to its proteolytic activity. While the role of acylated bacterial components in induction of inflammation is well-studied, little attention has been given to the potential role of the acylated nature of dentilisin. The purpose of this study was to test the hypothesis that T. denticola dentilisin activates a TLR2-dependent mechanism, leading to upregulation of tissue-destructive genes in periodontal tissue. RNA-sequencing of periodontal ligament cells challenged with T. denticola bacteria revealed significant upregulation of genes associated with extracellular matrix organization and degradation including potentially tissue-specific inducible MMPs that may play novel roles in modulating host immune responses that have yet to be characterized within the context of oral disease. The Gram-negative oral commensal, Veillonella parvula, failed to upregulate these same MMPs. Dentilisin-induced upregulation of MMPs was mediated via TLR2 and MyD88 activation, since knockdown of expression of either abrogated these effects. Challenge with purified dentilisin upregulated the same MMPs while a dentilisin-deficient T. denticola mutant had no effect. Finally, T. denticola-mediated activation of TLR2/MyD88 lead to the nuclear translocation of the transcription factor Sp1, which was shown to be a critical regulator of all T. denticola-dependent MMP expression. Taken together, these data suggest that T. denticola dentilisin stimulates tissue-destructive cellular processes in a TLR2/MyD88/Sp1-dependent fashion.

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Approaches to Understanding Mechanisms of Dentilisin Protease Complex Expression in Treponema denticola

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2021.668287 ◽

2021 ◽

Vol 11 ◽

Author(s):

M. Paula Goetting-Minesky ◽

Valentina Godovikova ◽

J. Christopher Fenno

Keyword(s):

Gene Expression ◽

Periodontal Disease ◽

Host Cell ◽

Protease Activity ◽

Alveolar Bone ◽

Three Dimensional ◽

Periodontal Pathogen ◽

Dimensional Structure ◽

Treponema Denticola ◽

Protease Gene

The oral spirochete Treponema denticola is a keystone periodontal pathogen that, in association with members of a complex polymicrobial oral biofilm, contributes to tissue damage and alveolar bone loss in periodontal disease. Virulence-associated behaviors attributed to T. denticola include disruption of the host cell extracellular matrix, tissue penetration and disruption of host cell membranes accompanied by dysregulation of host immunoregulatory factors. T. denticola dentilisin is associated with several of these behaviors. Dentilisin is an outer membrane-associated complex of acylated subtilisin-family PrtP protease and two other lipoproteins, PrcB and PrcA, that are unique to oral spirochetes. Dentilisin is encoded in a single operon consisting of prcB-prcA-prtP. We employ multiple approaches to study mechanisms of dentilisin assembly and PrtP protease activity. To determine the role of each protein in the protease complex, we have made targeted mutations throughout the protease locus, including polar and nonpolar mutations in each gene (prcB, prcA, prtP) and deletions of specific PrtP domains, including single base mutagenesis of key PrtP residues. These will facilitate distinguishing between host cell responses to dentilisin protease activity and its acyl groups. The boundaries of the divergent promoter region and the relationship between dentilisin and the adjacent iron transport operon are being resolved by incremental deletions in the sequence immediately 5’ to the protease locus. Comparison of the predicted three-dimensional structure of PrtP to that of other subtilisin-like proteases shows a unique PrtP C-terminal domain of approximately 250 residues. A survey of global gene expression in the presence or absence of protease gene expression reveals potential links between dentilisin and iron uptake and homeostasis in T. denticola. Understanding the mechanisms of dentilisin transport, assembly and activity of this unique protease complex may lead to more effective prophylactic or therapeutic treatments for periodontal disease.

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TheTreponema denticolaChymotrypsin-Like Protease Dentilisin Induces Matrix Metalloproteinase-2-Dependent Fibronectin Fragmentation in Periodontal Ligament Cells

Infection and Immunity ◽

10.1128/iai.01001-10 ◽

2010 ◽

Vol 79 (2) ◽

pp. 806-811 ◽

Cited By ~ 14

Author(s):

Di Miao ◽

J. Christopher Fenno ◽

John C. Timm ◽

Nam Eok Joo ◽

Yvonne L. Kapila

Keyword(s):

Periodontal Disease ◽

Periodontal Ligament ◽

Alveolar Bone ◽

Inflammatory Responses ◽

Tissue Homeostasis ◽

Matrix Metalloproteinase 2 ◽

Periodontal Ligament Cells ◽

Treponema Denticola ◽

Periodontal Pathogens ◽

Culture Supernatants

ABSTRACTPeriodontal disease is a bacterially mediated chronic inflammatory disease that results in destruction of the periodontal ligament (PDL) and alveolar bone that surround and support the dentition. While their precise roles are not well understood, periodontal pathogens, includingTreponema denticola, are believed to initiate the destructive inflammatory responses and dysregulation of tissue homeostasis that characterize the disease. These responses are believed to result from both proinflammatory effects of acylated bacterial membrane components (lipopolysaccharides and lipoproteins) and degradative effects of secreted bacterial proteases. Host-derived matrix metalloproteinases (MMPs) are key enzymes both in tissue homeostasis and tissue destruction. MMP expression is modulated in part by specific proteolytic fragments of fibronectin (FN), which are associated with periodontal disease. FN is a predominant extracellular matrix component in the periodontium. We examined the ability ofTreponema denticolaand its acylated outer membrane PrtP protease complex to induce both activation of MMP-2 and generation of FN fragments in human PDL cell culture supernatants.T. denticolaparent and isogenic mutant strains, as well as MMP-2 small interfering RNA and specific inhibitors of MMP-2 and PrtP activity, were used to examine protein expression, gelatinolytic activity, and FN fragmentation in culture supernatants.T. denticolaand its purified protease induced both MMP-2 activation and FN fragmentation. Here, we demonstrate that PrtP proteolytic activity induces the activation of MMP-2 and that active MMP-2 is required for FN fragmentation. These results suggest a specific mechanism by which theT. denticolaprotease may disrupt homeostatic processes required for the maintenance of periodontal health.

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