A new class of protein sensor links spirochete pleomorphism, persistence, and chemotaxis

Pathogenic spirochetes can alter their morphologies and behaviors to infect and survive within their hosts. Previous reports demonstrate that the formation of so-called round bodies and biofilms, and chemotaxis are involved in spirochete pathogenesis. Here, in the spirochete Treponema denticola, we report a direct link between these cellular states that involves a new class of protein sensor (CheWS) with hitherto unclear function. Using cryo-EM methods, protein modeling, bioinformatics, genetics methods, and behavioral assays we demonstrate that spirochetes regulate these behaviors in response to the small molecule s-adenosylmethionine (SAM) via a SAM sensor that is anchored to chemotaxis arrays. CheWS influences chemotaxis, biofilm and round body formation under non-stressed conditions by a novel sporulation-like mechanism. Taken together, we establish an improved model for round body formation, we discovered a direct link between this SAM sensor and changes in cellular states, as well as characterized a new sensor class involved in chemotaxis.

Title IgA Nephropathy and Oral Bacterial Species Related to Dental Caries and Periodontitis

A relationship between IgA nephropathy (IgAN) and bacterial infection has been suspected. As IgAN is a chronic disease, bacteria that could cause chronic infection in oral areas might be pathogenetic bacteria candidates. Oral bacterial species related to dental caries and periodontitis should be candidates because these bacteria are well known to be pathogenic in chronic dental disease. Recently, several reports have indicated that collagen-binding protein (cnm)-(+) Streptococcs mutans is relate to the incidence of IgAN and the progression of IgAN. Among periodontal bacteria, Treponema denticola, Porphyromonas gingivalis and Campylobacte rectus were found to be related to the incidence of IgAN. These bacteria can cause IgAN-like histological findings in animal models. While the connection between oral bacterial infection, such as infection with S. mutans and periodontal bacteria, and the incidence of IgAN remains unclear, these bacterial infections might cause aberrantly glycosylated IgA1 in nasopharynx-associated lymphoid tissue, which has been reported to cause IgA deposition in mesangial areas in glomeruli, probably through the alteration of microRNAs related to the expression of glycosylation enzymes. The roles of other factors related to the incidence and progression of IgA, such as genes and cigarette smoking, can also be explained from the perspective of the relationship between these factors and oral bacteria. This review summarizes the relationship between IgAN and oral bacteria, such as cnm-(+) S. mutans and periodontal bacteria.

EVALUATION OF SOME HIGH RISK BACTERIAL SPECIES IN THE ORAL MICROBIOME OF HNSCC PATIENTS

In this study we evaluated the composition of seven high risk periodontitis species of microorganisms in the oral microbiome of patients with different forms of head and neck squamous cell carcinoma (HNSCC). The laboratory analyses were performed using the method of quantitative real-time amplification (qPCR) of 26 saliva and mouth swab samples collected from HNSCC patients. Laboratory data regarding the normal or pathological presence of studied species were integrated with patients clinical conditions and some lifestyle factors. The results show that the highest frequency of pathological concentration is in the case of Fusobacterium nucleatum and Tannerella forsythia, while the lowest frequency is observed for microorganisms Aggregatibacter actinomycetemcomitans and Treponema denticola.

Periodontal pathogens as a risk factor for oral squamous cell carcinoma

Introduction. The associative role of the bacterial factor in the development of both primary malignant tumors of the oral mucosa and relapses is being actively discussed today. In the article published earlier, we have already described the possible mechanisms of action of periodontopathogenic microflora and its connection with the development of squamous cell carcinoma of the oral mucosa through cell proliferation, intracellular accumulation of pathogen, DNA replication and affect the signaling pathways of MARK (mitogen-activated protein kinase).Objective – to analyze the impact of periodontal pathogens on the risk of oral squamous cell carcinoma and its recurrence, as well as to evaluate the role of polymerase chain reaction and bacterial culture in the diagnosis of squamous cell carcinoma.Materials and methods. This study included 35 patients with stage Т3–4 squamous cell carcinoma, whose tumor tissue samples were tested for periodontal pathogens using culture and PCR. We analyzed 5 paraffin-embedded and 30 frozen tissue blocks from newly diagnosed (n = 15) and re-treatment (n = 15) patients.Results. We found that PCR was more sensitive than culture for the detection of possible etiological agents and predictors of squamous cell carcinoma (including Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola) (р <0.001). For example, Tannerella forsythia and Treponema denticola were detected only using PCR, whereas all cultures were negative. However, conventional culture proved to be more effective than PCR for the detection of Prevotella intermedia. Between 3 % and 100 % of newly diagnosed patients tested positive for Treponema denticola and some other periodontal pathogens (PCR) developed relapses, whereas among re-treatment patients, this proportion was 66.6 %.Conclusion. The combination of the culture method and the polymerase chain reaction method in the study of periodontopathogenic microflora has shown high efficiency in identifying possible predictors of squamous cell carcinoma of the oral mucosa and in preventing the development of chronic infectious periodontal diseases.

Virtual Screening to Identify the Protein Network Interaction of Hypericin with Red Complex Pathogens

Introduction: Hypericin is the anthraquinone derivative and has many properties like antiviral, antifungal and antibacterial. The red complex pathogens which include Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia in association with other microbes found in the periodontal pockets, cause severe inflammation resulting in periodontitis. Novel bioactive agents from several sources have been tested against the microbial pathogens to deduce antimicrobial activity. Aim: The aim of the study is to virtually screen and identify the protein network interaction of hypericin in red complex pathogens. Methodology: The STITCH v5.0 pipeline was primarily used to identify the drug-protein interactions. The VirulentPred and VICMPred software were used for elucidating the functional class of the proteins and virulence property. The sub cellular localization of virulent proteins was analysed with pSORTb v3.0 software. Further, the epitopes in virulent proteins were identified using BepiPred v1.0 linear epitope prediction tool. Results: Heat shock protein 90 of Porphyromonas gingivalis were found to involve in the cellular process and DNA topoisomerase IV subunit B, heat shock protein 90, DNA gyrase subunit A and DNA gyrase subunit B of Treponema denticola were found to be the virulent factors. The virulent proteins were located in the cytoplasm, which would further increase the potential effect of the drug to serve as antimicrobial agents. Finally, epitopes were predicted on the virulent proteins which can be specifically docked to further ascertain their interactions with the phytocompound. Conclusion: Hypericin with all its potential and biological benefits can be addressed, can be used as an antimicrobial agent to eradicate dental pathogens which are recalcitrant to treatment. The mode of action of hypericin is, it is targeting crucial proteins in red complex pathogens. Further in vitro studies should be performed on a wide range of pathogens to substantiate the true interactions between the drugs and the protein repertoire of pathogens.

Virtual Screening to Identify the Protein Network Interaction of Triclosan in Red Complex Pathogens

Background: Antimicrobial drug resistance is the major problem encountered world-wide. Novel therapeutic leads have been identified and are regularly tested for their activity against microbial pathogens. Aim: To identify the protein network interactions of triclosan in red complex pathogens. Materials and Methods: The present study follows an observational study design which aims to screen for the interaction of triclosan in red complex pathogens. The interaction was analyzed using the STITCH v.5 pipeline. The functional class of proteins identified were assessed using VICMPred and VirulentPred softwares. The microbial pathogens Treponema denticola ATCC 35405, Tannerella forsythia ATCC 43037, Porphyromonas gingivalis ATCC 33277 are the strains of red complex pathogens that are included in the present study. Results and Discussion: Several proteins were found to interact with triclosan. Among the protein interactions, interactions of triclosan with virulent proteins seems to have a greater impact. The NAD-dependent nucleotide-diphosphate-sugar epimerase [PGN_1370], Putative NAD dependent epimerase [PGN_1886], GDP-fucose synthetase [PGN_1079], Probable oxidoreductase [PGN_1360] of Porphyromonas gingivalis, Conserved hypothetical protein [TDE_2401], Epimerase/dehydratase family protein [TDE_1439] of Treponema denticola, NAD dependent epimerase/dehydratase family protein [BFO_2919], Hypothetical protein [BFO_1782], Nitroreductase family protein [BFO_1604] and Nitroreductase family protein [BFO_1516] Tannerella forsythia were found to be exhibit virulence nature. Conclusion: This study identifies the molecular targets of triclosan on red complex pathogens. As triclosan interacts with the red complex pathogens, in future it can be used as a primary medicine for periodontitis and some oral conditions.

Diversity of Treponema denticola and Other Oral Treponeme Lineages in Subjects with Periodontitis and Gingivitis

Periodontal diseases, such as periodontitis, are highly complex, multifactorial inflammatory infectious diseases affecting the gums and tooth-supporting structures. They are caused by chronic accumulations of dental plaque below the gum line that typically comprise hundreds of different bacterial species.

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

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.