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International Journal of Molecular... Apr 2024(Pg) and its gingipain proteases contribute to Alzheimer's disease (AD) pathogenesis through yet unclear mechanisms. Cellular secretion of small extracellular vesicles...
(Pg) and its gingipain proteases contribute to Alzheimer's disease (AD) pathogenesis through yet unclear mechanisms. Cellular secretion of small extracellular vesicles or exosomes (EXO) increases with aging as part of the senescence-associated secretory phenotype (SASP). We have shown that EXO isolated from Pg-infected dendritic cells contain gingipains and other Pg antigens and transmit senescence to bystander gingival cells, inducing alveolar bone loss in mice in vivo. Here, EXO were isolated from the gingiva of mice and humans with/without periodontitis (PD) to determine their ability to penetrate the blood-brain barrier (BBB) in vitro and in vivo. PD was induced by Pg oral gavage for 6 weeks in C57B6 mice. EXO isolated from the gingiva or brain of donor Pg-infected (PD EXO) or control animals (Con EXO) were characterized by NTA, Western blot, and TEM. Gingival PD EXO or Con EXO were labeled and injected into the gingiva of uninfected WT mouse model. EXO biodistribution in brains was tracked by an in vivo imaging system (IVIS) and confocal microscopy. The effect of human PD EXO on BBB integrity and permeability was examined using TEER and FITC dextran assays in a human in vitro 3D model of the BBB. Pg antigens (RGP and Mfa-1) were detected in EXO derived from gingival and brain tissues of donor Pg-infected mice. Orally injected PD EXO from donor mice penetrated the brains of recipient uninfected mice and colocalized with hippocampal microglial cells. IL-1β and IL-6 were expressed in human PD EXO and not in Con EXO. Human PD EXO promoted BBB permeability and penetrated the BBB in vitro. This is the first demonstration that microbial-induced EXO in the oral cavity can disseminate, cross the BBB, and may contribute to AD pathogenesis.
Topics: Blood-Brain Barrier; Animals; Humans; Mice; Extracellular Vesicles; Porphyromonas gingivalis; Periodontitis; Gingiva; Mice, Inbred C57BL; Male; Exosomes; Female; Bacteroidaceae Infections
PubMed: 38674094
DOI: 10.3390/ijms25084509 -
Microbiome Jul 2023Porphyromonas gingivalis (hereafter "Pg") is an oral pathogen that has been hypothesized to act as a keystone driver of inflammation and periodontal disease. Although Pg...
BACKGROUND
Porphyromonas gingivalis (hereafter "Pg") is an oral pathogen that has been hypothesized to act as a keystone driver of inflammation and periodontal disease. Although Pg is most readily recovered from individuals with actively progressing periodontal disease, healthy individuals and those with stable non-progressing disease are also colonized by Pg. Insights into the factors shaping the striking strain-level variation in Pg, and its variable associations with disease, are needed to achieve a more mechanistic understanding of periodontal disease and its progression. One of the key forces often shaping strain-level diversity in microbial communities is infection of bacteria by their viral (phage) predators and symbionts. Surprisingly, although Pg has been the subject of study for over 40 years, essentially nothing is known of its phages, and the prevailing paradigm is that phages are not important in the ecology of Pg.
RESULTS
Here we systematically addressed the question of whether Pg are infected by phages-and we found that they are. We found that prophages are common in Pg, they are genomically diverse, and they encode genes that have the potential to alter Pg physiology and interactions. We found that phages represent unrecognized targets of the prevalent CRISPR-Cas defense systems in Pg, and that Pg strains encode numerous additional mechanistically diverse candidate anti-phage defense systems. We also found that phages and candidate anti-phage defense system elements together are major contributors to strain-level diversity and the species pangenome of this oral pathogen. Finally, we demonstrate that prophages harbored by a model Pg strain are active in culture, producing extracellular viral particles in broth cultures.
CONCLUSION
This work definitively establishes that phages are a major unrecognized force shaping the ecology and intra-species strain-level diversity of the well-studied oral pathogen Pg. The foundational phage sequence datasets and model systems that we establish here add to the rich context of all that is already known about Pg, and point to numerous avenues of future inquiry that promise to shed new light on fundamental features of phage impacts on human health and disease broadly. Video Abstract.
Topics: Humans; Bacteriophages; Porphyromonas gingivalis; Prophages; Periodontal Diseases; Base Sequence
PubMed: 37491415
DOI: 10.1186/s40168-023-01607-w -
Reviews in the Neurosciences Jan 2024Peripheral inflammation could constitute a risk factor for AD. This review summarizes the research related to peripheral inflammation that appears to have a relationship... (Review)
Review
Peripheral inflammation could constitute a risk factor for AD. This review summarizes the research related to peripheral inflammation that appears to have a relationship with Alzheimer's disease. We find there are significant associations between AD and peripheral infection induced by various pathogens, including herpes simplex virus type 1, cytomegalovirus, Epstein-Barr virus, human immunodeficiency virus, severe acute respiratory syndrome coronavirus 2, , , and . Chronic inflammatory diseases are also reported to contribute to the pathophysiology of AD. The mechanisms by which peripheral inflammation affects the pathophysiology of AD are complex. Pathogen-derived neurotoxic molecule composition, disrupted BBB, and dysfunctional neurogenesis may all play a role in peripheral inflammation, promoting the development of AD. Anti-pathogenic medications and anti-inflammatory treatments are reported to decrease the risk of AD. Studies that could improve understanding the associations between AD and peripheral inflammation are needed. If our assumption is correct, early intervention against inflammation may be a potential method of preventing and treating AD.
Topics: Humans; Alzheimer Disease; Epstein-Barr Virus Infections; Herpesvirus 4, Human; Inflammation; Anti-Inflammatory Agents
PubMed: 37602685
DOI: 10.1515/revneuro-2023-0049 -
Molecular Oral Microbiology Jan 2024Microbial biofilms promote pathogenesis by disguising antigens, facilitating immune evasion, providing protection against antibiotics and other antimicrobials and,... (Review)
Review
Microbial biofilms promote pathogenesis by disguising antigens, facilitating immune evasion, providing protection against antibiotics and other antimicrobials and, generally, fostering survival and persistence. Environmental fluxes are known to influence biofilm formation and composition, with recent data suggesting that tobacco and tobacco-derived stimuli are particularly important mediators of biofilm initiation and development in vitro and determinants of polymicrobial communities in vivo. The evidence for tobacco-augmented biofilm formation by oral bacteria, tobacco-induced oral dysbiosis, tobacco-resistance strategies, and bacterial physiology is summarized herein. A general overview is provided alongside specific insights gained through studies of the model and archetypal, anaerobic, Gram-negative oral pathobiont, Porphyromonas gingivalis.
PubMed: 38229003
DOI: 10.1111/omi.12450 -
Oral Diseases Oct 2023The objective of the study was to evaluate the prevalence and proportions of antibiotic-resistant species in periodontitis patients. (Review)
Review
OBJECTIVES
The objective of the study was to evaluate the prevalence and proportions of antibiotic-resistant species in periodontitis patients.
METHODS
A systematic scoping review of randomized clinical trials (RCTs) was conducted using the PRISMA extension for scoping reviews involving different databases. MeSH terms and keywords were provided to examine only RCTs with antibiotic-resistant results that included at least 3 months of follow-up of systematically healthy patients diagnosed with periodontitis and treated with systemic or local antibiotics adjunctive to subgingival debridement. RCTs that managed participants surgically, duplicate publications, and investigations implemented on animals were discarded.
RESULTS
Six RCTs were chosen. These studies included 465 patients. Most investigations observed that while Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Porphyromonas gingivalis had low resistance to amoxicillin, microorganisms in many sites showed resistance to tetracycline, metronidazole, and azithromycin pretreatment. A. actinomycetemcomitans showed high resistance to tetracycline pre- and post-therapy. The proportion of antibiotic-resistant samples augmented rapidly after the prescription of antibiotics in all test groups. The percentage of antibiotic-resistant microorganisms decreased over time; at the end of the follow-up period, resistance levels were close to baseline levels.
CONCLUSIONS
Adjunctive local and systemic antibiotic treatment temporarily increased the antibiotic resistance of subgingival microorganisms; nonetheless, many bacteria remained susceptible to antibiotics during their administration.
Topics: Humans; Randomized Controlled Trials as Topic; Periodontitis; Anti-Bacterial Agents; Tetracycline; Porphyromonas gingivalis; Drug Resistance, Microbial; Aggregatibacter actinomycetemcomitans
PubMed: 35735133
DOI: 10.1111/odi.14288 -
Scientific Reports Mar 2024Porphyromonas gingivalis, a Gram-negative anaerobic bacterium commonly found in human subgingival plaque, is a major etiologic agent for periodontitis and has been...
Porphyromonas gingivalis, a Gram-negative anaerobic bacterium commonly found in human subgingival plaque, is a major etiologic agent for periodontitis and has been associated with multiple systemic pathologies. Many P. gingivalis strains have been identified and different strains possess different virulence factors. Current oral microbiome approaches (16S or shotgun) have been unable to differentiate P. gingivalis strains. This study presents a new approach that aims to improve the accuracy of strain identification, using a detection method based on sequencing of the intergenic spacer region (ISR) which is variable between P. gingivalis strains. Our approach uses two-step PCR to amplify only the P. gingivalis ISR region. Samples are then sequenced with an Illumina sequencer and mapped to specific strains. Our approach was validated by examining subgingival plaque from 153 participants with and without periodontal disease. We identified the avirulent strain ATCC33277/381 as the most abundant strain across all sample types. The W83/W50 strain was significantly enriched in periodontitis, with 13% of participants harboring that strain. Overall, this approach can have significant implications not only for the diagnosis and treatment of periodontal disease but also for other diseases where P. gingivalis or its toxins have been implicated, such as Alzheimer's disease.
Topics: Humans; Porphyromonas gingivalis; Base Composition; Sequence Analysis, DNA; RNA, Ribosomal, 16S; Phylogeny; Periodontitis
PubMed: 38485747
DOI: 10.1038/s41598-024-56849-x -
Molecular Oral Microbiology Aug 2023Porphyromonas gingivalis is an oral pathogen that promotes dysbiosis by quenching the bactericidal activity of the host immune system while maintaining chronic...
Porphyromonas gingivalis is an oral pathogen that promotes dysbiosis by quenching the bactericidal activity of the host immune system while maintaining chronic inflammation, leading to periodontitis. This involves the secretion of virulence factors such as P. gingivalis peptidyl arginine deiminase (PPAD), which converts the C-terminal Arg residues of bacterial and host-derived proteins and peptides into citrulline. We have previously shown that PPAD activity and major fimbriae (containing FimA) are necessary for P. gingivalis to activate Toll-like receptor 2 (TLR2). TLR2 is an important component of the innate immune system and plays a predominant role in the recognition of P. gingivalis by host cells. Here, we extend those findings to show that P. gingivalis strains deficient for PPAD and fimbriae induced almost identical transcriptional profiles in infected primary human gingival fibroblasts (PHGFs), but these differed substantially from the transcriptome elicited by the wild-type ATCC 33277 strain. Apparently, PPAD-modified fimbriae trigger the host cell response to P. gingivalis, as confirmed by showing that the proinflammatory host cell response mediated by TLR2 is dependent on PPAD activity and the presence of fimbriae, with type I fimbriae as the most potent TLR2 activators. We also found that PPAD-modified accessory fimbrial subunits (FimC, FimD, and FimE) alone or in combination are TLR2 ligands in a reporter cell line. Although FimA polymerization to form the fimbrial shaft was not required for TLR2 activation, the secretion and proteolytic maturation of FimA were necessary for signaling by accessory Fim proteins. This was supported by showing that the proinflammatory activation of PHGFs is dependent on PPAD and accessory fimbrial subunits. We conclude that accessory fimbrial subunits are modified by PPAD and stimulate the response to P. gingivalis infection in a TLR2-dependent manner.
Topics: Humans; Protein-Arginine Deiminases; Porphyromonas gingivalis; Toll-Like Receptor 2; Fimbriae, Bacterial; Gingiva
PubMed: 37347653
DOI: 10.1111/omi.12427 -
Journal of Periodontology Nov 2023Chronic periodontitis (CP), the most prevalent dysbiotic bacteria-driven chronic inflammatory disease, is an underestimated global health problem in itself, and due to a...
BACKGROUND
Chronic periodontitis (CP), the most prevalent dysbiotic bacteria-driven chronic inflammatory disease, is an underestimated global health problem in itself, and due to a causative relationship with other disorders such as cardiovascular diseases or Alzheimer disease. The CP pathogenesis is primarily driven by Porphyromonas gingivalis in humans, and Porphyromonas gulae in dogs. These microorganisms initiate a pathogenic shift in the composition of the tooth-surface microflora. Our objective was to evaluate antimicrobial effects of bestatin, a potential CP drug candidate.
METHODS
We evaluated bestatin bacteriostatic efficiency against periodontopathogens in planktonic cultures via microplate assay, and mono- and multispecies oral biofilm models. Neutrophil bactericidal activities, such as phagocytosis, were investigated in vitro using granulocytes isolated from the peripheral blood. The therapeutic efficacy and the immunomodulatory function of bestatin was assessed in a murine model of CP.
RESULTS
Bestatin exhibited bacteriostatic activity against both P. gingivalis and P. gulae, and controlled the formation and species composition of the biofilm. We demonstrated that bestatin promotes the phagocytosis of periodontopathogens by neutrophils. Finally, we found that providing bestatin in the animal feed prevented alveolar bone resorption.
CONCLUSIONS
We show that in a murine model of CP bestatin not only shifted the biofilm species composition from pathogenic to a commensal one, but also promoted bacteria clearance by immune cells and alleviated inflammation. Taken together, these results suggest that bestatin is a promising drug choice for the treatment and/or prevention of periodontitis and clinical trials are required to fully evaluate its potency.
Topics: Humans; Dogs; Animals; Mice; Disease Models, Animal; Leucine; Chronic Periodontitis; Porphyromonas gingivalis; Alveolar Bone Loss
PubMed: 37021727
DOI: 10.1002/JPER.22-0614 -
Scientific Reports Jul 2023The Arg-specific gingipains of Porphyromonas gingivalis RgpA and RgpB have 97% identical sequences in their catalytic domains yet their propeptides are only 76%...
The Arg-specific gingipains of Porphyromonas gingivalis RgpA and RgpB have 97% identical sequences in their catalytic domains yet their propeptides are only 76% identical. RgpA isolates as a proteinase-adhesin complex (HRgpA) which hinders direct kinetic comparison of RgpA as a monomer with monomeric RgpB. We tested modifications of rgpA identifying a variant that enabled us to isolate histidine-tagged monomeric RgpA (rRgpAH). Kinetic comparisons between rRgpAH and RgpB used benzoyl-L-Arg-4-nitroanilide with and without cysteine and glycylglycine acceptor molecules. With no glycylglycine, values of K, V, k and k/K for each enzyme were similar, but with glycylglycine K decreased, V increased and k increased ~ twofold for RgpB but ~ sixfold for rRgpAH. The k/K for rRgpAH was unchanged whereas that of RgpB more than halved. Recombinant RgpA propeptide inhibited rRgpAH and RgpB with K 13 nM and 15 nM K respectively slightly more effectively than RgpB propeptide which inhibited rRgpAH and RgpB with K 22 nM and 29 nM respectively (p < 0.0001); a result that may be attributable to the divergent propeptide sequences. Overall, the data for rRgpAH reflected observations previously made by others using HRgpA, indicating rRgpAH fidelity and confirming the first production and isolation of functional affinity tagged RgpA.
Topics: Gingipain Cysteine Endopeptidases; Cysteine Endopeptidases; Peptide Hydrolases; Adhesins, Bacterial; Catalytic Domain; Porphyromonas gingivalis; Hemagglutinins
PubMed: 37402780
DOI: 10.1038/s41598-023-37534-x -
Microbiology Spectrum Jul 2024has been associated with progression of periodontitis, characterized by inflammation and destruction of periodontal tissues. Here, we report that matcha, a product of ,...
UNLABELLED
has been associated with progression of periodontitis, characterized by inflammation and destruction of periodontal tissues. Here, we report that matcha, a product of , hampers the adherence and survival of through multiple tactics. Matcha extract (ME) inhibited the growth not only of but also of s and , while it did not inhibit growth of nine species of oral streptococci and . ME-mediated growth inhibition was characterized by both morphological and physiological changes at the bacterial envelope, which were accompanied by nano-particle formation and decreased membrane fluidity/permeability without loss of membrane integrity. ME also triggered autoaggregation of in a major fimbriae (FimA)-dependent manner. In addition, adherence of was dramatically inhibited by ME, irrespective of fimbriae. Furthermore, a structure-activity relationship study tested a series of catechins isolated from ME and identified the pyrogallol-type B-ring of catechins as essential for growth inhibition. In a clinical study to assess the microbiological and therapeutic effects of matcha mouthwash in patients with periodontitis, the number in saliva was significantly reduced by matcha mouthwash compared to the pre-intervention level. A tendency toward improvement in probing pocket depth was observed in the matcha group, although the difference was not statistically significant. Taken together, we present a proof of concept, based on the multimodal inhibitory effect of matcha against , and that matcha may have clinical applicability for prevention and treatment of periodontitis.
IMPORTANCE
Periodontitis, a multifactorial inflammatory disease of the oral cavity, results in alveolar bone destruction, and is a major cause of tooth loss of humans. In addition, emerging evidence has demonstrated associations between periodontitis and a wide range of other chronic inflammation-driven disorders, including diabetes mellitus, preterm birth, cardiovascular disease, aspiration pneumonia, rheumatoid arthritis, cognitive disorder, and cancer. In the present study, we report that matcha, a product of , hampers , a major periodontal pathobiont, in not only a series of experiments but also a pilot intervention clinical trial of patients with periodontitis, in which matcha mouthwash statistically significantly reduced the number in saliva, as compared to the pre-intervention level. Taken together, we suggest that matcha may have clinical applicability for prevention and treatment of periodontitis.
Topics: Porphyromonas gingivalis; Humans; Periodontitis; Anti-Bacterial Agents; Bacterial Adhesion; Plant Extracts; Catechin; Fusobacterium nucleatum; Adult; Prevotella nigrescens; Female; Bacteroidaceae Infections; Male; Aggregatibacter actinomycetemcomitans
PubMed: 38771061
DOI: 10.1128/spectrum.03426-23