Pathogen In Periodontitis Research Articles

Gingipains are the important virulence factors of Porphyromonas gingivalis downregulating B10 cells.

Porphyromonas gingivalis (P. gingivalis) is a keystone pathogen in periodontitis. Our previous study indicated that periodontitis induced by P. gingivalis increased the percentage of CD19+ B cells, but decreased the ratio of IL-10 producing regulatory B cells (B10) in collagen-induced arthritis (CIA) mice. It's still unclear which virulence factors of P. gingivalis are involved in these processes. Here, we compared the effects of different components of P. gingivalis on the biogenesis of B10 cells, and found that the decreased proportion of B10 cells was mainly resulted from the undenatured proteins other than the DNA, RNA or LPS of P. gingivalis. As gingipains are enzymes and virulence factors which play vital role in the progression in periodontitis through affecting innate and adaptive immune system, we then compared the influence of the wild-type (WT) strain of P. gingivalis (ATCC 33277) and its isogenic gingipain-null mutant (∆K∆RAB) on differentiation of splenic B cells into B10 cells. Interestingly, compared to WT strain, ∆K∆RAB treatment increased the frequency of B10 cells as well as expression of IL-6 in B cells. Furthermore, the acute peritonitis, an ideal model for quick evaluation of immune effects of agents, induced by ∆K∆RAB showed higher IL-6 production and proportion of B10 cells compared with WT. Finally, we performed transcriptomic analysis to better understand the effects and possible mechanism of gingipains on B cells. Compared with WT, ∆K∆RAB upregulated the PI3K-Akt pathway of B cells which is important for IL-10 production and B10 cell biogenesis, and more activated Jak-STAT pathway which is a classical signaling pathway mediated by IL-6. Cumulatively, this study preliminarily revealed that gingipains of P. gingivalis are vital virulence factors downregulating B10 cells and altering immune responses. This article is protected by copyright. All rights reserved.

Anti-Porphyromonas gingivalis nanotherapy for maintaining bacterial homeostasis in periodontitis

Periodontitis is caused by oral flora imbalance, which leads to immune imbalance. Porphyromonas gingivalis is a keystone pathogen in periodontitis, causing the blooming of inflammophilic microbes, and becoming dormant to resist antibiotics. Targeted interventions are needed to destroy this pathogen and collapse its inflammophilic flora. Therefore, a targeting nanoagent antibody-conjugated liposomal drug carrier with ginsenoside Rh2 (A-L-R) was developed for pleiotropic benefits. A-L-R showed high quality in high-performance liquid chromatography (HPLC), Fourier transform infrared (FTIR), and transmission electron microscope (TEM) detection. Only P. gingivalis was influenced by A-L-R, as shown by live/dead cell staining and a series of antimicrobial effects assays. With fluorescence in situ hybridization (FISH) staining and in propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR), the clearance of P. gingivalis by A-L-R was more than for other groups, and only the proportion of P. gingivalis was reduced by A-L-R in monospecies culture. Moreover, in a periodontitis model, A-L-R targeted P. gingivalis with high efficiency and low toxicity, maintaining homeostasis with a relatively stable oral microflora. This targeting nanomedicine offers new strategies for periodontitis therapy, providing a foundation for the prevention and treatment of periodontitis.

Effects of periodontitis on cancer outcomes in the era of immunotherapy.

Periodontitis results from dysbiosis of the oral microbiome and affects up to 70% of US adults aged 65 years and older. More than 50 systemic inflammatory disorders and comorbidities are associated with periodontitis, many of which overlap with immunotherapy-associated toxicities. Despite the increasing use of immunotherapy for the treatment of cancer, uncertainty remains as to whether the microbial shift associated with periodontal disease can influence response rates and tolerance to cancer immunotherapy. We herein review the pathophysiology of periodontitis and the local and systemic inflammatory conditions related to oral dysbiosis, and discuss the overlapping adverse profiles of periodontitis and immunotherapy. The effects of the presence of Porphyromonas gingivalis, a key pathogen in periodontitis, highlight how the oral microbiome can affect the hosts' systemic immune responses, and further research into the local and systemic influence of other microorganisms causing periodontal disease is necessary. Addressing periodontitis in an ageing population of people with cancer could have potential implications for the clinical response to (and tolerability of) immunotherapy and warrants further investigation.

Effect of Lubanum and Potash Alum on Co-aggregation and Biofilm Formation of Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia

Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia can co- aggregate in a more stable and resistant multispecies biofilm. Therefore, the current study aimed to test the effectiveness of lubanum and potash alum solutions, as a natural rinse, to affect the attachment between the cells and the multispecies biofilm of these periodontitis pathogens, and also to enhance the action of the chemical rinse, BioFresh K (chlorhexidine (CHX)). The results revealed that the solutions of 12 mg/ ml of both natural substances can prevent bacterial co- aggregation, and the solutions of 40 mg/ ml of natural substances and 1.2 mg/ml of CHX can affect the cells in their polymicrobial population after 1hr exposure. The results also revealed that increasing the concentration of lubanum made it possible to affect the resistant preformed multispecies biofilm and the effect became more maxima when it was used in combination with other agents. This combination is benefit in controlling the chronic periodontitis caused by these pathogens as it can reinforce the effect of antibacterial agents on multispecies biofilm and prevent the attachment of new cells without the need of increasing the concentration or combination between chemical therapies.

P. gingivalis-LPS Induces Mitochondrial Dysfunction Mediated by Neuroinflammation through Oxidative Stress.

Porphyromonas gingivalis (P. gingivalis), a key pathogen in periodontitis, is associated with neuroinflammation. Periodontal disease increases with age; 70.1% of adults 65 years and older have periodontal problems. However, the P. gingivalis- lipopolysaccharide (LPS)induced mitochondrial dysfunction in neurodegenerative diseases remains elusive. In this study, we investigated the possible role of P. gingivalis-LPS in mitochondrial dysfunction during neurodegeneration. We found that P. gingivalis-LPS treatment activated toll-like receptor (TLR) 4 signaling and upregulated the expression of Alzheimer's disease-related dementia and neuroinflammatory markers. Furthermore, the LPS treatment significantly exacerbated the production of reactive oxygen species and reduced the mitochondrial membrane potential. Our study highlighted the pivotal role of P. gingivalis-LPS in the repression of serum response factor (SRF) and its co-factor p49/STRAP that regulate the actin cytoskeleton. The LPS treatment repressed the genes involved in mitochondrial function and biogenesis. P. gingivalis-LPS negatively altered oxidative phosphorylation and glycolysis and reduced total adenosine triphosphate (ATP) production. Additionally, it specifically altered the mitochondrial functions in complexes I, II, and IV of the mitochondrial electron transport chain. Thus, it is conceivable that P. gingivalis-LPS causes mitochondrial dysfunction through oxidative stress and inflammatory events in neurodegenerative diseases.

Efficient clearance of periodontitis pathogens by S. gordonii membrane-coated H2O2 self-supplied nanocomposites in a "Jenga" style.

As a key pathogen of periodontitis, P. gingivalis requires support of the initial colonizing bacterium (S. gordonii preferably) to form symbiotic biofilms on gingival tissues with enhanced antibiotic resistance. Here, we report a new strategy to treat periodontitis biofilms with S. gordonii membrane-coated H2O2 self-supplied nanocomposites (ZnO2/Fe3O4@MV NPs) in a "Jenga" style. Integration of our special MV coatings enables selectively enhanced internalization of the cargos in S. gordonii, thus inducing severe damage to the foundational bacterial layer and collapse/clearance of symbiotic biofilms consequently. This strategy allows us to clear the symbiotic biofilms of S. gordonii and P. gingivalis with active hydroxyl radicals (˙OH) derived from ZnO2-Fe3O4@MV NPs in a H2O2 self-supplied, nanocatalyst-assisted manner. This "Jenga-style" treatment provides a cutting-edge proof of concept for the removal of otherwise robust symbiotic biofilms of periodontitis where the critical pathogens are difficult to target and have antibiotic resistance.

A unique network of attack, defence and competence on the outer membrane of the periodontitis pathogen Tannerella forsythia.

Periodontopathogenic Tannerella forsythia uniquely secretes six peptidases of disparate catalytic classes and families that operate as virulence factors during infection of the gums, the KLIKK-peptidases. Their coding genes are immediately downstream of novel ORFs encoding the 98-132 residue potempins (Pot) A, B1, B2, C, D and E. These are outer-membrane-anchored lipoproteins that specifically and potently inhibit the respective downstream peptidase through stable complexes that protect the outer membrane of T. forsythia, as shown in vivo. Remarkably, PotA also contributes to bacterial fitness in vivo and specifically inhibits matrix metallopeptidase (MMP) 12, a major defence component of oral macrophages, thus featuring a novel and highly-specific physiological MMP inhibitor. Information from 11 structures and high-confidence homology models showed that the potempins are distinct β-barrels with either a five-stranded OB-fold (PotA, PotC and PotD) or an eight-stranded up-and-down fold (PotE, PotB1 and PotB2), which are novel for peptidase inhibitors. Particular loops insert like wedges into the active-site cleft of the genetically-linked peptidases to specifically block them either via a new "bilobal" or the classic "standard" mechanism of inhibition. These results discover a unique, tightly-regulated proteolytic armamentarium for virulence and competence, the KLIKK-peptidase/potempin system.

The Antimicrobial and Anti-Biofilm Effects of Hypericum perforatum Oil on Common Pathogens of Periodontitis: An In Vitro Study.

The antibacterial and anti-biofilm effects of Hypericum perforatum oil against the common pathogens of periodontitis (Escherichia coli, Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis, Porphyromonas gingivalis) was investigated. Disk diffusion (DD), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) approaches were applied to test the antimicrobial effects. In order to determine the anti-biofilm effects, the amount of bacterial biofilm formation was assessed using the microtiter plate technique. The anti-biofilm effects were then confirmed by determining the minimum biofilm inhibitor concentration (MBIC). The MIC, MBC, MBIC, and DD values were 64, 256, 512 μg/mL, and 14 mm for Staphylococcus aureus; 128, 256, 512 μg/mL, and 16 mm for Streptococcus mutans; 256, 512, 256 μg/mL, and 20 mm for Escherichia coli; 32, 128, 512 µg/mL, and 16 mm for Enterococcus faecalis; and 64, 128, 256 µg/mL, and 15 mm for Porphyromonas gingivalis, respectively. According to our results, Hypericum perforatum oil has antibacterial and anti-biofilm properties against the common bacteria associated with periodontitis.

A GntR family transcription factor in Porphyromonas gingivalis regulates bacterial growth, acylpeptidyl oligopeptidase, and gingipains activity.

Porphyromonas gingivalis is a keystone pathogen for periodontitis. The function of the GntR family transcription factor is poorly studied in P. gingivalis. Numerous processes govern bacterial growth. The survival and pathogenicity of P. gingivalis depend heavily on its capacity to acquire amino acids as nutritional sources. In this investigation, a GntR transcription factor, pg1007, was identified in P. gingivalis, the deletion of which significantly inhibited bacterial growth. The mutant strain also exhibited an increased extracellular activity of gingipains and acylpeptidyl oligopeptidase (AOP). Global gene expression profiling revealed that the expression levels of 59 genes were significantly altered in the Δpg1007 mutant, with an upregulation in gene expression for AOP, ABC transporters, and some membrane proteins. In addition, His-PG1007 protein was purified as a recombinant protein from Escherichia coli, and the conserved DNA sequence bound by it was determined using electrophoretic mobility shift assays and DNase I footprinting assays. Consequently, this study demonstrated that pg1007 is a crucial transcription factor in P. gingivalis and regulates the bacterial growth and activity of gingipains and AOP. These findings may enhance our understanding of the regulation of bacterial proliferation and protease activity in P. gingivalis.

Continuous Oral Administration of Sonicated P. gingivalis Delays Rat Skeletal Muscle Healing Post-Treadmill Training.

Background: A delay in muscle repair interferes with the effect of training or exercise; therefore, it is important to identify the factors that delay muscle repair. P. gingivalis, one of the most common periodontal disease pathogens, has the potential to inhibit muscle repair after training, as inferred from a previous study. To assess the expression of satellite cells in this in vivo study, we evaluated the relationship between P. gingivalis and muscle regeneration after training. Methods: A total of 20 male Wistar rats (eight weeks in age) were randomly divided into two groups: one orally administered sonicated P. gingivalis four times per week for six weeks (PG group) and one given no treatment (NT group). After four weeks of training using a treadmill, the gastrocnemius was evaluated using histology of the cross-sectional area (CSA) of myotubes and immunohistochemistry of the expression of skeletal muscle satellite cells. In addition, an endurance test was performed a day before euthanization. Results: The CSA and expression of Pax7+/MyoD− and Pax7+/MyoD+ cells were not significantly different between the groups. However, the expression of Pax7−/MyoD+ cells and running time until exhaustion were significantly lower in the PG group. Conclusions: Infection with P. gingivalis likely interferes with muscle repair after training.

Entamoeba gingivalis is associated with periodontal conditions in Chinese young patients: A cross-sectional study.

BackgroundThis study investigated the prevalence and relative abundance of Entamoeba gingivalis (E. gingivalis) in Chinese young patients with different periodontal conditions, and its association with subgingival microbial composition, periodontal parameters, and cytokines in gingival crevicular fluid.MethodsParticipants (age: 18–45 years) diagnosed with stage II–IV periodontitis, gingivitis, or periodontal health underwent periodontal examination and sampling. Subgingival plaque was analyzed by 16S+18S sequencing for E. gingivalis detection and microbial analysis. The distribution of E. gingivalis in subgingival plaque was illustrated by fluorescence in situ hybridization. Interleukin-1β, interleukin-8, and tumor necrosis factor-α in gingival crevicular fluid were measured by multiplexed flow cytometric assay.ResultsThis cross-sectional study included 120 sites from 60 participants. The prevalence and relative abundance of E. gingivalis were significantly increased in periodontitis (p<0.05). The sites were classified into three subgroups according to the relative abundance of E. gingivalis: negative group (Eg0, n=56); low-abundance group (Eg1, n=32); and high-abundance group (Eg2, n=32). The subgingival microflora in the subgroups showed stepwise changes at both the phylum and genus levels. The microflora compositions were significantly altered from Eg0 to Eg2 (p<0.001). Co-occurrence network analysis showed that Porphyromonas, Treponema, Tannerella, Filifactor, TG5, and Desulfobulbus were highly correlated with E. gingivalis (r>0.6, p<0.001). Correlation analysis showed that E. gingivalis was closely associated with important periodontal parameters and cytokines (p<0.01).Conclusion E. gingivalis was enriched in periodontitis and closely associated with subgingival microbial dysbiosis, periodontal parameters and cytokines in gingival crevicular fluid. Thus, it may be an important pathogen in periodontal disease.

Rodent Gingival Tissue Culture in an Aging Experimental Model: A Pilot Study

Background: Gingiva acts as a barrier to prevent further invasion of pathogens in periodontitis. The gingival structure consists of epithelial tissue and connective tissue. As the aging process continues, there are several changes in the periodontium. Previous studies have tried to investigate the complex interaction between the host immune system and bacteria by using animal models, especially rodents. Objective: The aim of the study was to evaluate the effectiveness of collecting gingival tissue from the palate and retromolar pad. Materials and Methods: The aging experimental model had two age categories of male rodents of 18 and 58 weeks. Tissue was collected from the mandible retromolar pad and palate with full-thickness excision. Tissues were transferred to a complete medium at 4°C. Gingival tissue was cultured in a 37°C culture incubator at 5% CO2. Tissue proliferation was observed on the first, third, and fifth days using the hemocytometer. The cell metabolism rate between the two age categories was checked using the MTT Assay. Two-way ANOVA was used for statistical analysis. Results: Gingival tissues obtained from the experimental models of two age categories were alive, and proliferation was observed. The old rodent group showed no significant result in terms of cell morphology on the first vs. third day (p&gt;0.05), but significant results were found on the first vs. fifth day and third day vs. the fifth day (p&lt;0.05). The young rodent group showed the most significant morphology changes between days. In both young and old categories, no significant difference was observed in the cell metabolism. Conclusion: Rodent gingival tissue collection from the retromolar pad and palate was found suitable for tissue culture in the aging experimental study.

Pretreatment of macrophage-membrane-coated nanoparticles for therapeutical targeting of P. gingivalis-accelerated atherosclerosis

Atherosclerosis (AS) as a chronically inflammatory disease is the mainly cause of mortality worldwide. Porphyromonas gingivalis (P. gingivalis, Pg), one primary pathogen in periodontitis (PD), has been reported to promote the progression of atherosclerosis via inducing infectiously triggered immune response, thus accelerating atheromatous plaque formation. However, limited therapeutic potency has been achieved using traditional drug treatment due to the existence of Pg and low concentration of drug reached in AS, reminding us to develop a new drug delivery strategy. In this study, to simultaneously realize the pathogen elimination and inflammation resolution in Pg-infected region, the PLGA-simvastatin-chitosan-metronidazole nanoparticles (STNPs) were coated with Pg-treated macrophage membranes (MM/STNPs). These nanoparticles obviously eliminated the amount of Pg and effectively switched the activation of macrophages from an inflammatory M1-like state to a more immunosuppressive M2-like phenotype. Using Pg-treated macrophage membrane (MM), the MM/STNPs were efficiently targeted in both atheromatous plaque and periodontal tissue in vivo. Importantly, MM/STNPs injection simultaneously diminished the atheromatous plaque formation in AS and rejuvenated the alveolar bone loss in PD. Based on this specific Pg-targeted delivery, the biomimetic nanoparticles provide a new approach for the targeting strategy in the treatment of Pg-accelerated AS.

Aggregatibacter actinomycetemcomitans and Filifactor alocis: Two exotoxin-producing oral pathogens.

Periodontitis is a dysbiotic disease caused by the interplay between the microbial ecosystem present in the disease with the dysregulated host immune response. The disease-associated microbial community is formed by the presence of established oral pathogens like Aggregatibacter actinomycetemcomitans as well as by newly dominant species like Filifactor alocis. These two oral pathogens prevail and grow within the periodontal pocket which highlights their ability to evade the host immune response. This review focuses on the virulence factors and potential pathogenicity of both oral pathogens in periodontitis, accentuating the recent description of F. alocis virulence factors, including the presence of an exotoxin, and comparing them with the defined factors associated with A. actinomycetemcomitans. In the disease setting, possible synergistic and/or mutualistic interactions among both oral pathogens might contribute to disease progression.

Macrophages: A communication network linking Porphyromonas gingivalis infection and associated systemic diseases.

Porphyromonas gingivalis (P. gingivalis) is a Gram-negative anaerobic pathogen that is involved in the pathogenesis of periodontitis and systemic diseases. P. gingivalis has recently been detected in rheumatoid arthritis (RA), cardiovascular disease, and tumors, as well as Alzheimer’s disease (AD), and the presence of P. gingivalis in these diseases are correlated with poor prognosis. Macrophages are major innate immune cells which modulate immune responses against pathogens, however, multiple bacteria have evolved abilities to evade or even subvert the macrophages’ immune response, in which subsequently promote the diseases’ initiation and progression. P. gingivalis as a keystone pathogen of periodontitis has received increasing attention for the onset and development of systemic diseases. P. gingivalis induces macrophage polarization and inflammasome activation. It also causes immune response evasion which plays important roles in promoting inflammatory diseases, autoimmune diseases, and tumor development. In this review, we summarize recent discoveries on the interaction of P. gingivalis and macrophages in relevant disease development and progression, such as periodontitis, atherosclerosis, RA, AD, and cancers, aiming to provide an in-depth mechanistic understanding of this interaction and potential therapeutic strategies.

Porphyromonas gingivalis: A key role in Parkinson's disease with cognitive impairment?

Cognitive impairment (CI) is a common complication of Parkinson's disease (PD). The major features of Parkinson's disease with cognitive impairment (PD-CI) include convergence of α-Synuclein (α-Syn) and Alzheimer's disease (AD)-like pathologies, neuroinflammation, and dysbiosis of gut microbiota. Porphyromonas gingivalis (P. gingivalis) is an important pathogen in periodontitis. Recent research has suggested a role of P. gingivalis and its virulence factor in the pathogenesis of PD and AD, in particular concerning neuroinflammation and deposition of α-Synuclein (α-Syn) and amyloid-β (Aβ). Furthermore, in animal models, oral P. gingivalis could cause neurodegeneration through regulating the gut-brain axis, suggesting an oral-gut-brain axis might exist. In this article, we discussed the pathological characteristics of PD-CI and the role of P. gingivalis in them.

Influence of Gallic Acid-Containing Mouth Spray on Dental Health and Oral Microbiota of Healthy Cats-A Pilot Study.

Simple SummaryPeriodontal diseases are common dental issues in cats. Oral care supplements were used to prevent diseases and maintain oral health. Moreover, maintaining a healthy oral microbiome is crucial for oral health. Therefore, we have developed a gallic acid-containing mouth spray and studied its effect on oral microbiota and dental health in healthy cats. The results revealed that the gingival and plaque indexes were improved after 42 days of mouth spray treatment in cats. The mouth spray treatment also reduced the abundance of harmful bacterial load and supported the growth of normal oral microbiota. This preliminary study recommended that the gallic acid-containing mouth spray could be an essential oral product to improve the oral hygiene of the cats.This pilot study aimed to investigate the effects of gallic acid-containing mouth spray on oral microbiota in healthy cat subjects. Forty healthy cats were recruited and randomly allocated to the control (G1; n = 20) and treatment groups (G2; n = 20). The cats were treated with mouth spray twice daily for 42 days. The changes in the gingival index (GI) and plaque index (PI) were measured at baseline (day 0) and end of the study (42nd day). The changes in the oral microbial composition of representative animals (control, n = 9; and treatment, n = 8) were also evaluated at baseline and end of the study. Oral microbial composition was assessed by amplifying the V1–V3 region of the 16S rRNA gene from supragingival dental plaque DNA extracts. The sequences were annotated using the QIIME 2.0. The GI and PI were significantly reduced after 42 days of treatment. The deep sequencing revealed that mouth spray influenced the cats’ oral microbiome and was significantly diverse. About 20 phyla and 59 species were observed after 42 days of mouth spray usage in cats’ oral microbiota. The number of operational taxonomic units (OTUs) of post-treatment samples (PoTS) of G2 was greatly reduced compared to other samples. Further analysis revealed that mouth spray acts substantially against Desulfomicrobium orale, one of the known pathogens in periodontal disease. The mouth spray efficiently reduced the growth of 22 species and uprooted 17 species. Moreover, the mouth spray supported the growth of normal oral microbiota, including Moraxella and Neisseria species. The preliminary study suggested that the gallic acids-containing mouth spray could be an essential oral product to improve the oral hygiene of the cats. Moreover, further studies are needed to confirm the beneficial effect of mouth spray on cats.

A Photoacoustic-Fluorescent Imaging Probe for Proteolytic Gingipains Expressed by Porphyromonas gingivalis.

Porphyromonas gingivalis is a keystone pathogen in periodontal disease. We herein report a dual-modal fluorescent and photoacoustic imaging probe for the detection of gingipain proteases secreted by P. gingivalis. Upon proteolytic cleavage by Arg-specific gingipain (RgpB), five-fold photoacoustic enhancement and >100-fold fluorescence activation was measured with detection limits of 1.1 nM RgpB and 5.0E4 CFU mL-1 bacteria in vitro. RgpB activity was imaged in porcine jaws with low-nanomolar sensitivity. Diagnostic efficacy was evaluated in gingival crevicular fluid samples from subjects with and without periodontal disease, wherein activation was correlated to qPCR-based detection of P. gingivalis (Pearson's r=0.71). Finally, photoacoustic imaging of RgpB-cleaved probe was achieved in murine brains ex vivo, with relevance and potential utility for disease models of general infection by P. gingivalis, motivated by the recent biological link between gingipain and Alzheimer's disease.

A Photoacoustic‐Fluorescent Imaging Probe for Proteolytic Gingipains Expressed by Porphyromonas gingivalis

AbstractPorphyromonas gingivalis is a keystone pathogen in periodontal disease. We herein report a dual‐modal fluorescent and photoacoustic imaging probe for the detection of gingipain proteases secreted by P. gingivalis. Upon proteolytic cleavage by Arg‐specific gingipain (RgpB), five‐fold photoacoustic enhancement and &gt;100‐fold fluorescence activation was measured with detection limits of 1.1 nM RgpB and 5.0E4 CFU mL−1 bacteria in vitro. RgpB activity was imaged in porcine jaws with low‐nanomolar sensitivity. Diagnostic efficacy was evaluated in gingival crevicular fluid samples from subjects with and without periodontal disease, wherein activation was correlated to qPCR‐based detection of P. gingivalis (Pearson's r=0.71). Finally, photoacoustic imaging of RgpB‐cleaved probe was achieved in murine brains ex vivo, with relevance and potential utility for disease models of general infection by P. gingivalis, motivated by the recent biological link between gingipain and Alzheimer's disease.

Recombinant Porphyromonas gingivalis W83 FimA alters immune response and metabolic gene expression in oral squamous carcinoma cells.

ObjectivesThe Gram‐negative anaerobic rod Porphyromonas gingivalis (P. gingivalis) is regarded as a keystone pathogen in periodontitis and expresses a multitude of virulence factors iincluding fimbriae that are enabling adherence to and invasion in cells and tissues. The progression of periodontitis is a consequence of the interaction between the host immune response and periodontal pathogens. The aim of this study was to investigate the genome‐wide impact of recombinant fimbrial protein FimA from P. gingivalis W83 on the gene expression of oral squamous carcinoma cells by transcriptome analysis.Materials and MethodsHuman squamous cell carcinoma cells (SCC‐25) were stimulated for 4 and 24 h with recombinant FimA. RNA sequencing was performed and differential gene expression and enrichment were analyzed using gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and REACTOME. The results of transcriptome analysis were validated using quantitative real‐time polymerase chain reaction (PCR) with selected genes.ResultsDifferential gene expression after 4 and 24 h revealed upregulation of 464 (4 h) and 179 genes (24 h) and downregulation of 69 (4 h) and 312 (24 h) genes. GO, KEGG, and REACTONE enrichment analysis identified a strong immunologic transcriptomic response signature after 4 h. After 24 h, mainly those genes were regulated, which belonged to cell metabolic pathways and replication. Real‐time PCR of selected genes belonging to immune response and signaling demonstrated strong upregulation of CCL20, TNFAIP6, CXCL8, TNFAIP3, and NFkBIA after both stimulation times.ConclusionsThese data shed light on the RNA transcriptome of human oral squamous carcinoma epithelial cells following stimulation with P. gingivalis FimA and identify a strong immunological gene expression response to this virulence factor. The data provide a base for future studies of molecular and cellular interactions between P. gingivalis and oral epithelium to elucidate basic mechanisms that may provide new prospects for periodontitis therapy and give new insights into the development and possible treatments of cancer.