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Microbiology and Immunology Oct 2020Pili or fimbriae, which are filamentous structures present on the surface of bacteria, were purified from a periodontal pathogen, Porphyromonas gingivalis, in 1980s. The... (Review)
Review
Pili or fimbriae, which are filamentous structures present on the surface of bacteria, were purified from a periodontal pathogen, Porphyromonas gingivalis, in 1980s. The protein component of pili (stalk pilin), which is its major component, was named FimA; it has a molecular weight of approximately 41 kDa. Because the molecular weight of the pilin from P. gingivalis is twice that of pilins from other bacterial pili, the P. gingivalis Fim pili were suggested to be formed via a novel mechanism. In earlier studies, we reported that the FimA pilin is secreted on the cell surface as a lipoprotein precursor, and the subsequent N-terminal processing of the FimA precursor by arginine-specific proteases is necessary for Fim pili formation. The crystal structures of FimA and its related proteins were determined recently, which show that Fim pili are formed by a protease-mediated strand-exchange mechanism. The most recent study conducted by us, wherein we performed cryoelectron microscopy of the pilus structure, provided evidence in support of this mechanism. As the P. gingivalis Fim pili are formed through novel transport and assembly mechanisms, such pili are now designated as Type V pili. Surface lipoproteins, including the anchor pilin FimB of Fim pili that are present on the outer membrane, have been detected in certain Gram-negative bacteria. Here, we describe the assembly mechanisms of pili, including those of Type V and other pili, as well as the lipoprotein transport mechanisms.
Topics: Crystallography, X-Ray; Fimbriae Proteins; Fimbriae, Bacterial; Lipoproteins; Periodontitis; Porphyromonas gingivalis; Protein Conformation; Protein Transport
PubMed: 32816331
DOI: 10.1111/1348-0421.12838 -
Scientific Reports Aug 2022Dysbiosis of the oral microbiota plays an important role in the progression of periodontitis, which is characterized by chronic inflammation and alveolar bone loss, and...
Dysbiosis of the oral microbiota plays an important role in the progression of periodontitis, which is characterized by chronic inflammation and alveolar bone loss, and associated with systemic diseases. Bacterial extracellular vesicles (EVs) contain various bioactive molecules and show diverse effects on host environments depending on the bacterial species. Recently, we reported that EVs derived from Filifactor alocis, a Gram-positive periodontal pathogen, had osteoclastogenic activity. In the present study, we analysed the osteoclastogenic potency and immunostimulatory activity of EVs derived from the Gram-negative periodontal pathogens Porphyromonas gingivalis and Tannerella forsythia, the oral commensal bacterium Streptococcus oralis, and the gut probiotic strain Lactobacillus reuteri. Bacterial EVs were purified by density gradient ultracentrifugation using OptiPrep (iodixanol) reagent. EVs from P. gingivalis, T. forsythia, and S. oralis increased osteoclast differentiation and osteoclstogenic cytokine expression in osteoclast precursors, whereas EVs from L. reuteri did not. EVs from P. gingivalis, T. forsythia, and S. oralis preferentially activated Toll-like receptor 2 (TLR2) rather than TLR4 or TLR9, and induced osteoclastogenesis mainly through TLR2. The osteoclastogenic effects of EVs from P. gingivalis and T. forsythia were reduced by both lipoprotein lipase and polymyxin B, an inhibitor of lipopolysaccharide (LPS), while the osteoclastogenic effects of EVs from S. oralis were reduced by lipoprotein lipase alone. These results demonstrate that EVs from periodontal pathogens and oral commensal have osteoclastogenic activity through TLR2 activation by lipoproteins and/or LPS.
Topics: Cell Differentiation; Extracellular Vesicles; Lipopolysaccharides; Lipoprotein Lipase; Microbiota; Mouth; Osteoclasts; Porphyromonas gingivalis; Toll-Like Receptor 2; Toll-Like Receptor 4
PubMed: 35987920
DOI: 10.1038/s41598-022-18412-4 -
Frontiers in Cellular and Infection... 2022The association between periodontal disease and systemic disease has become a research hotspot. (), a crucial periodontal pathogen, affects the development of systemic... (Review)
Review
The association between periodontal disease and systemic disease has become a research hotspot. (), a crucial periodontal pathogen, affects the development of systemic diseases. The pathogenicity of is largely linked to interference with the host's immunity. This review aims to discover the role of in the modulation of the host's adaptive immune system through a large number of virulence factors and the manipulation of cellular immunological responses (mainly mediated by T cells). These factors may affect the cause of large numbers of systemic diseases, such as atherosclerosis, hypertension, adverse pregnancy outcomes, inflammatory bowel disease, diabetes mellitus, non-alcoholic fatty liver disease, rheumatoid arthritis, and Alzheimer's disease. The point of view of adaptive immunity may provide a new idea for treating periodontitis and related systemic diseases.
Topics: Female; Pregnancy; Humans; Porphyromonas gingivalis; Immunity, Cellular; Periodontal Diseases; Adaptive Immunity; Alzheimer Disease
PubMed: 36467726
DOI: 10.3389/fcimb.2022.1026457 -
European Journal of Clinical... Nov 2020Porphyromonas gingivalis, a major subgingival plaque bacterium in periodontitis, has recently attracted much attention as a possible microbial driver in Alzheimer's... (Review)
Review
Porphyromonas gingivalis, a major subgingival plaque bacterium in periodontitis, has recently attracted much attention as a possible microbial driver in Alzheimer's disease. In the present paper, another common neuroinflammatory disease, Parkinson's disease (PD), is discussed. A recent study found major virulence factors of P. gingivalis such as gingipain R1 (RgpA) and lipopolysaccharide in the blood circulation of a PD population. The current review reveals how features such as systemic inflammation, hypercoagulation, presence of amyloid fibrin(ogen) in plasma, and marked ultrastructural changes in platelets, probably induced by P. gingivalis, may affect the development of PD. Several other clinical studies have also demonstrated an association between periodontitis and PD. Even if the risk of periodontal diseases causing neurological disorders needs to be better substantiated, that should not keep us from trying to prevent them by performing careful daily dental hygiene.
Topics: Humans; Parkinson Disease; Porphyromonas gingivalis; Virulence Factors
PubMed: 32564247
DOI: 10.1007/s10096-020-03944-2 -
Future Microbiology 2015Porphyromonas gingivalis is one of the keystone pathogens associated with chronic periodontitis. All P. gingivalis strains examined thus far produce outer membrane... (Review)
Review
Porphyromonas gingivalis is one of the keystone pathogens associated with chronic periodontitis. All P. gingivalis strains examined thus far produce outer membrane vesicles. Recent studies have found that vesicles possess some well-known virulence factors of P. gingivalis such as adhesins, toxins and proteolytic enzymes. Carrying most of the characteristic features of their parent P. gingivalis cells, vesicles communicate with host cells and other members of microbial biofilms, resulting in the transmission of virulence factors into these host cells and the formation of pathogenic bacteria-dominated microbial communities. An in-depth understanding of both the nature and role of vesicles in the pathogenicity of P. gingivalis is both important and timely, particularly when speaking of periodontitis and its related systemic effects.
Topics: Adhesins, Bacterial; Biofilms; Humans; Microbial Consortia; Organelle Biogenesis; Periodontitis; Porphyromonas gingivalis; Transport Vesicles; Virulence Factors
PubMed: 26343879
DOI: 10.2217/fmb.15.63 -
International Journal of Molecular... Feb 2021Human oral and gut microbiomes are crucial for maintenance of homeostasis in the human body. , the key etiologic agent of chronic periodontitis, can cause dysbiosis in...
Human oral and gut microbiomes are crucial for maintenance of homeostasis in the human body. , the key etiologic agent of chronic periodontitis, can cause dysbiosis in the mouth and gut, which results in local and systemic infectious inflammatory diseases. Our previous work resulted in extensive biochemical and functional characterization of one of the major heme acquisition systems (Hmu), with the leading role played by the HmuY hemophore-like protein. We continued our studies on the homologous heme acquisition protein (Bvu) expressed by the dominant species of the gut microbiome. Results from spectrophotometric experiments showed that Bvu binds heme preferentially under reducing conditions using Met145 and Met172 as heme iron-coordinating ligands. Bvu captures heme bound to human serum albumin and only under reducing conditions. Importantly, HmuY is able to sequester heme complexed to Bvu. This is the first study demonstrating that expresses a heme-binding hemophore-like protein, thus increasing the number of members of a novel HmuY-like family. Data gained in this study confirm the importance of HmuY in the context of survival in regard to its ability to cause dysbiosis also in the gut microbiome.
Topics: Bacterial Proteins; Bacteroides; Heme; Humans; Porphyromonas gingivalis; Protein Binding
PubMed: 33668119
DOI: 10.3390/ijms22052237 -
Trends in Microbiology Jan 2021Proteases are critical virulence determinants of Porphyromonas gingivalis, an emerging Alzheimer's disease, cancer, and arthritis pathogen and established agent of... (Review)
Review
Proteases are critical virulence determinants of Porphyromonas gingivalis, an emerging Alzheimer's disease, cancer, and arthritis pathogen and established agent of periodontitis. Transposon sequencing has been employed to define the core essential genome of this bacterium and genes conditionally essential in multiple environments - abscess formation; epithelial colonization; and cigarette smoke toxin exposure; as well as to elucidate genes required for iron acquisition and a functional type 9 secretion system. Validated and predicted protein catabolism genes identified include a combination of established virulence factors and a larger set of seemingly more mundane proteolytic genes. The functions and relevance of genes that share essentiality in multiple disease-relevant conditions are examined. These common stress-related genes may represent particularly attractive therapeutic targets for the control of P. gingivalis infections.
Topics: Animals; Bacterial Proteins; Bacteroidaceae Infections; Genes, Essential; Humans; Porphyromonas gingivalis; Virulence Factors
PubMed: 33071035
DOI: 10.1016/j.tim.2020.09.002 -
Frontiers in Cellular and Infection... 2023
Topics: Humans; Porphyromonas gingivalis; Immune Evasion; Dysbiosis; Periodontal Diseases
PubMed: 37842000
DOI: 10.3389/fcimb.2023.1289103 -
International Journal of... Jun 2015It seems that Porphyromanas gingivalis is carcinogenic, because it activates a number of inflammatory immune responses in the host and causes disorders in bacterial... (Meta-Analysis)
Meta-Analysis
It seems that Porphyromanas gingivalis is carcinogenic, because it activates a number of inflammatory immune responses in the host and causes disorders in bacterial clearance mechanisms. There is little information on the prevalence of this bacterium in cancer patients. The aim of this study was to evaluate and compare the prevalence of P. gingivalis in cancer patients by meta-analysis methods.Different databases including PubMed, EMBASE, the Cochrane Library, Scopus, and ISI web of Knowledge were investigated and eight relevant articles published in 2000-2013 were finally analyzed. Data were analyzed by meta-analysis method, fixed effect model. I² statistics were calculated to examine the heterogeneity of papers. The information was analyzed by R and STATA Ver 12.2.A total of 711 people infected with P. gingivalis were included in this study. In total, the prevalence of P. gingivalis was 40.7% (95% CI, 19.3-62.1). The prevalence of P. gingivalis was evaluated in four case-control studies. The results of this study showed that P. gingivalis increased the chance of cancer development and periodontal disease as much as 1.36 times (OR, 1.36; 95%CI, 0.47-3.97).Although there was no significant correlation between P. gingivalis and cancer, this bacterium increased the chance of cancer and periodontal disease and could be considered as a main potential risk factor.
Topics: Adolescent; Bacteroidaceae Infections; Case-Control Studies; Humans; Middle Aged; Neoplasms; Periodontal Diseases; Porphyromonas gingivalis; Prevalence; Risk Factors
PubMed: 26002887
DOI: 10.1177/0394632015586144 -
Clinical and Experimental Dental... Apr 2023This review was conducted to assess the effectiveness of xylitol against Porphyromonas gingivalis anaerobic species, a key microbe contributing to periodontal disease... (Review)
Review
OBJECTIVE
This review was conducted to assess the effectiveness of xylitol against Porphyromonas gingivalis anaerobic species, a key microbe contributing to periodontal disease pathogenesis.
MATERIAL AND METHODS
Relevant studies published on seven online databases (Cochrane, Ovid, Pubmed, Pubmed Central, Scopus, Google Scholar, and Web of Science) were included in accordance with the PRISMA guidelines. Inclusion criteria allowed all study designs involving xylitol and P. gingivalis, literature published since the year 2000, and all xylitol delivery forms.
RESULTS
The initial search yielded 186 papers. After the removal of duplicates, five reviewers screened every article for eligibility and seven articles were selected for data extraction. Four out of seven included studies assessed the dose-dependent effect of xylitol on P. gingivalis growth, two studies assessed the effect of xylitol on P. gingivalis-induced cytokine expression, and one study assessed both domains.
CONCLUSIONS
From the in vitro studies included in this systematic review, there is some evidence of xylitol's inhibitory effect on P. gingivalis. However, more evidence derived from in vivo studies is required to confirm its effectiveness warranting their routine use.
Topics: Humans; Porphyromonas gingivalis; Xylitol; Periodontal Diseases; Cytokines
PubMed: 36894516
DOI: 10.1002/cre2.724