ABSTRACT
Periodontitis is a severe gum infection that begins as gingivitis and can lead to gum recession, bone loss, and tooth loss if left untreated. It is primarily caused by bacterial infection, which triggers inflammation and the formation of periodontal pockets. Notably, periodontitis is associated with systemic health issues and has been linked to heart disease, diabetes, respiratory diseases, adverse pregnancy outcomes, and cancers. Accordingly, the presence of chronic inflammation and immune system dysregulation in individuals with periodontitis significantly contributes to the initiation and progression of various cancers, particularly oral cancers. These processes promote genetic mutations, impair DNA repair mechanisms, and create a tumor-supportive environment. Moreover, the bacteria associated with periodontitis produce harmful byproducts and toxins that directly damage the DNA within oral cells, exacerbating cancer development. In addition, chronic inflammation not only stimulates cell proliferation but also inhibits apoptosis, causes DNA damage, and triggers the release of pro-inflammatory cytokines. Collectively, these factors play a crucial role in the progression of cancer in individuals affected by periodontitis. Further, specific viral and bacterial agents, such as hepatitis B and C viruses, human papillomavirus (HPV), Helicobacter pylori (H. pylori), and Porphyromonas gingivalis, contribute to cancer development through distinct mechanisms. Bacterial infections have systemic implications for cancer development, while viral infections provoke immune and inflammatory responses that can lead to genetic mutations. This review will elucidate the link between periodontitis and cancers, particularly oral cancers, exploring their underlying mechanisms to provide insights for future research and treatment advancements.
Subject(s)
Mouth Neoplasms , Periodontitis , Humans , Periodontitis/complications , Periodontitis/microbiology , Mouth Neoplasms/microbiology , Mouth Neoplasms/genetics , Animals , Inflammation/complications , Porphyromonas gingivalis/pathogenicityABSTRACT
OBJECTIVES: Oral microbiome dysbiosis prevention is important to avoid the onset and progression of periodontal disease. Dipotassium glycyrrhizate (GK2) is a licorice root extract with anti-inflammatory effects, and its associated mechanisms have been well-reported. However, their effects on the oral microbiome have not been investigated. This study aimed to elucidate the effects of GK2 on the oral microbiome using an in vitro polymicrobial biofilm model. METHODS: An in vitro saliva-derived polymicrobial biofilm model was used to evaluate the effects of GK2 on the oral microbiome. One-week anaerobic culture was performed, in which GK2 was added to the medium. Subsequently, microbiome analysis was performed based on the V1-V2 region of the 16 S rRNA gene, and pathogenicity indices were assessed. We investigated the effects of GK2 on various bacterial monocultures by evaluating its inhibitory effects on cell growth, based on culture turbidity. RESULTS: GK2 treatment altered the microbiome structure and decreased the relative abundance of periodontal pathogenic bacteria, including Porphyromonas. Moreover, GK2 treatment reduced the DPP4 activity -a pathogenicity index of periodontal disease. Specifically, GK2 exhibited selective antibacterial activity against periodontal pathogenic bacteria. CONCLUSIONS: These findings suggest that GK2 has a selective antibacterial effect against periodontal pathogenic bacteria; thus, preventing oral microbiome dysbiosis. Therefore, GK2 is expected to contribute to periodontal disease prevention by modulating the oral microbiome toward a state with low inflammatory potential, thereby utilizing its anti-inflammatory properties on the host.
Subject(s)
Biofilms , Dysbiosis , Glycyrrhizic Acid , Porphyromonas gingivalis , Saliva , Biofilms/drug effects , Dysbiosis/microbiology , Saliva/microbiology , Porphyromonas gingivalis/drug effects , Porphyromonas gingivalis/pathogenicity , Glycyrrhizic Acid/pharmacology , Humans , In Vitro Techniques , Microbiota/drug effects , Glycyrrhiza/chemistry , Periodontal Diseases/microbiology , Periodontal Diseases/prevention & control , RNA, Ribosomal, 16S/geneticsABSTRACT
Porphyromonas gingivalis is a gram-negative anaerobic bacterium recognized for its pivotal role in the pathogenesis of periodontal diseases. This review covers an overview of the virulence factors and lifecycle stages of P. gingivalis, with a specific focus on attachment and colonization, biofilm formation, growth and multiplication, dormancy survival and dissemination. Additionally, we explore the significance of inter-bacterial cross-feeding within biofilms. Furthermore, we discuss potential phytochemical-based strategies to target P. gingivalis, including the use of curcumin, apigenin, quercetin and resveratrol. Understanding the virulence factors and lifecycle stages of P. gingivalis, along with the promising phytochemical-based interventions, holds promise for advancing strategies in periodontal disease management and oral health promotion.
Subject(s)
Biofilms , Periodontal Diseases , Phytochemicals , Porphyromonas gingivalis , Virulence Factors , Porphyromonas gingivalis/drug effects , Porphyromonas gingivalis/pathogenicity , Porphyromonas gingivalis/growth & development , Porphyromonas gingivalis/physiology , Humans , Phytochemicals/pharmacology , Phytochemicals/therapeutic use , Biofilms/drug effects , Biofilms/growth & development , Periodontal Diseases/microbiology , Periodontal Diseases/drug therapyABSTRACT
Periodontitis is linked to the onset and progression of oral squamous cell carcinoma (OSCC), an epidemiologically frequent and clinically aggressive malignancy. In this context, Fusobacterium (F.) nucleatum and Porphyromonas (P.) gingivalis, two bacteria that cause periodontitis, are found in OSCC tissues as well as in oral premalignant lesions, where they exert pro-tumorigenic activities. Since the two bacteria are present also in endodontic diseases, playing a role in their pathogenesis, here we analyze the literature searching for information on the impact that endodontic infection by P. gingivalis or F. nucleatum could have on cellular and molecular events involved in oral carcinogenesis. Results from the reviewed papers indicate that infection by P. gingivalis and/or F. nucleatum triggers the production of inflammatory cytokines and growth factors in dental pulp cells or periodontal cells, affecting the survival, proliferation, invasion, and differentiation of OSCC cells. In addition, the two bacteria and the cytokines they induce halt the differentiation and stimulate the proliferation and invasion of stem cells populating the dental pulp or the periodontium. Although most of the literature confutes the possibility that bacteria-induced endodontic inflammatory diseases could impact on oral carcinogenesis, the papers we have analyzed and discussed herein recommend further investigations on this topic.
Subject(s)
Fusobacterium Infections , Fusobacterium nucleatum , Mouth Neoplasms , Porphyromonas gingivalis , Humans , Porphyromonas gingivalis/pathogenicity , Fusobacterium nucleatum/pathogenicity , Mouth Neoplasms/microbiology , Mouth Neoplasms/pathology , Fusobacterium Infections/microbiology , Fusobacterium Infections/complications , Carcinogenesis , Bacteroidaceae Infections/microbiology , Bacteroidaceae Infections/complications , Carcinoma, Squamous Cell/microbiology , Carcinoma, Squamous Cell/etiology , Carcinoma, Squamous Cell/pathology , Periodontitis/microbiology , Animals , Cytokines/metabolismABSTRACT
Porphyromonas gingivalis (Pg), a Gram-negative oral pathogen, promotes and accelerates periodontitis-associated gut disorders. Intestinal epithelial barrier dysfunction is crucial in the pathogenesis of intestinal and systemic diseases. In this study, we sought to elucidate the protective role of cinnamaldehyde (CNM, an activator of Nrf2) against P. gingivalis (W83) and Pg-derived lipopolysaccharide (Pg-LPS) induced intestinal epithelial barrier dysfunction via antioxidative mechanisms in IEC-6 cells. IEC-6 (ATCC, CRL-1592) cells were pretreated with or without CNM (100 µM), in the presence or absence of P. gingivalis (strain W83, 109 MOI) or Pg-LPS (1, 10, and 100 µg/mL), respectively, between 0-72 h time points by adopting a co-culture method. Intestinal barrier function, cytokine secretion, and intestinal oxidative stress protein markers were analyzed. P. gingivalis or Pg-LPS significantly (p < 0.05) increased reactive oxygen species (ROS) and malondialdehyde (MDA) levels expressing oxidative stress damage. Pg-LPS, as well as Pg alone, induces inflammatory cytokines via TLR-4 signaling. Furthermore, infection reduced Nrf2 and NAD(P)H quinone dehydrogenase 1 (NQO1). Interestingly, inducible nitric oxide synthase (iNOS) protein expression significantly (p < 0.05) increased with Pg-LPS or Pg infection, with elevated levels of nitric oxide (NO). CNM treatment suppressed both Pg- and Pg-LPS-induced intestinal oxidative stress damage by reducing ROS, MDA, and NO production. Furthermore, CNM treatment significantly upregulated the expression of tight junction proteins via increasing the phosphorylation levels of PI3K/Akt/Nrf2 suppressing inflammatory cytokines. CNM protected against Pg infection-induced intestinal epithelial barrier dysfunction by activating the PI3K/Akt-mediated Nrf2 signaling pathway in IEC-6 cells.
Subject(s)
Acrolein , Intestinal Mucosa , NF-E2-Related Factor 2 , Nitric Oxide , Phosphatidylinositol 3-Kinases , Porphyromonas gingivalis , Proto-Oncogene Proteins c-akt , Signal Transduction , NF-E2-Related Factor 2/metabolism , Acrolein/analogs & derivatives , Acrolein/pharmacology , Animals , Signal Transduction/drug effects , Proto-Oncogene Proteins c-akt/metabolism , Rats , Porphyromonas gingivalis/pathogenicity , Phosphatidylinositol 3-Kinases/metabolism , Intestinal Mucosa/metabolism , Intestinal Mucosa/drug effects , Intestinal Mucosa/microbiology , Intestinal Mucosa/pathology , Nitric Oxide/metabolism , Cell Line , Lipopolysaccharides , Oxidative Stress/drug effects , Epithelial Cells/metabolism , Epithelial Cells/drug effects , Toll-Like Receptor 4/metabolism , Reactive Oxygen Species/metabolism , Cytokines/metabolismABSTRACT
Porphyromonas gingivalis is a nonmotile, obligate anaerobic, Gram-negative bacterium known for its association with periodontal disease and its involvement in systemic diseases such as atherosclerosis, cardiovascular disease, colon cancer, and Alzheimer's disease. This bacterium produces several virulence factors, including capsules, fimbriae, lipopolysaccharides, proteolytic enzymes, and hemagglutinins. A comparative genomic analysis revealed the open pangenome of P. gingivalis and identified complete type IV secretion systems in strain KCOM2805 and almost complete type VI secretion systems in strains KCOM2798 and ATCC49417, which is a new discovery as previous studies did not find the proteins involved in secretion systems IV and VI. Conservation of some virulence factors between different strains was observed, regardless of their genetic diversity and origin. In addition, we performed for the first time a reconstruction analysis of the gene regulatory network, identifying transcription factors and proteins involved in the regulatory mechanisms of bacterial pathogenesis. In particular, QseB regulates the expression of hemagglutinin and arginine deaminase, while Rex may suppress the release of gingipain through interactions with PorV and the formatum/nitrate transporter. Our study highlights the central role of conserved virulence factors and regulatory pathways, particularly QseB and Rex, in P. gingivalis and provides insights into potential therapeutic targets.
Subject(s)
Gene Regulatory Networks , Genome, Bacterial , Metabolic Networks and Pathways , Porphyromonas gingivalis , Virulence Factors , Porphyromonas gingivalis/genetics , Porphyromonas gingivalis/metabolism , Porphyromonas gingivalis/pathogenicity , Virulence Factors/genetics , Metabolic Networks and Pathways/genetics , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Humans , Gene Expression Regulation, BacterialABSTRACT
BACKGROUND: Benign prostatic hyperplasia (BPH) is the most common disease in elderly men. There is increasing evidence that periodontitis increases the risk of BPH, but the specific mechanism remains unclear. This study aimed to explore the role and mechanism of the key periodontal pathogen Porphyromonas gingivalis (P. gingivalis) in the development of BPH. METHODS: The subgingival plaque (Sp) and prostatic fluid (Pf) of patients with BPH concurrent periodontitis were extracted and cultured for 16S rDNA sequencing. Ligature-induced periodontitis, testosterone-induced BPH and the composite models in rats were established. The P. gingivalis and its toxic factor P. gingivalis lipopolysaccharide (P.g-LPS) were injected into the ventral lobe of prostate in rats to simulate its colonization of prostate. P.g-LPS was used to construct the prostate cell infection model for mechanism exploration. RESULTS: P. gingivalis, Streptococcus oralis, Capnocytophaga ochracea and other oral pathogens were simultaneously detected in the Pf and Sp of patients with BPH concurrent periodontitis, and the average relative abundance of P. gingivalis was found to be the highest. P. gingivalis was detected in both Pf and Sp in 62.5% of patients. Simultaneous periodontitis and BPH synergistically aggravated prostate histological changes. P. gingivalis and P.g-LPS infection could induce obvious hyperplasia of the prostate epithelium and stroma (epithelial thickness was 2.97- and 3.08-fold that of control group, respectively), and increase of collagen fibrosis (3.81- and 5.02-fold that of control group, respectively). P. gingivalis infection promoted prostate cell proliferation, inhibited apoptosis, and upregulated the expression of inflammatory cytokines interleukin-6 (IL-6; 4.47-fold), interleukin-6 receptor-α (IL-6Rα; 5.74-fold) and glycoprotein 130 (gp130; 4.47-fold) in prostatic tissue. P.g-LPS could significantly inhibit cell apoptosis, promote mitosis and proliferation of cells. P.g-LPS activates the Akt pathway through IL-6/IL-6Rα/gp130 complex, which destroys the imbalance between proliferation and apoptosis of prostate cells, induces BPH. CONCLUSION: P. gingivalis was abundant in the Pf of patients with BPH concurrent periodontitis. P. gingivalis infection can promote BPH, which may affect the progression of BPH via inflammation and the Akt signaling pathway.
Subject(s)
Interleukin-6 , Porphyromonas gingivalis , Prostatic Hyperplasia , Receptors, Interleukin-6 , Male , Prostatic Hyperplasia/complications , Porphyromonas gingivalis/pathogenicity , Rats , Humans , Animals , Interleukin-6/analysis , Interleukin-6/metabolism , Prostate , Periodontitis/complications , Periodontitis/microbiology , Aged , Middle Aged , Rats, Sprague-Dawley , Disease Models, Animal , Signal Transduction/physiologyABSTRACT
OBJECTIVE: Porphyromonas gingivalis (P. gingivalis) is a key etiological agent in periodontitis and functions as a facultative intracellular microorganism and involves many virulence factors. These virulence factors participate in multiple intracellular processes, like ferroptosis, the mechanistic underpinnings remain to be elucidated. Aim of this study was to investigate the effects of virulence factors on the host cells. DESIGN: Human umbilical vein endothelial cells (HUVECs) were treated with 4% paraformaldehyde-fixed P. gingivalis, and subsequent alterations in gene expression were profiled via RNA-seq. Further, the molecules associated with ferroptosis were quantitatively analyzed using qRT-PCR and Western blot. RESULTS: A total of 1125 differentially expressed genes (DEGs) were identified, encompassing 225 upregulated and 900 downregulated. Ferroptosis was conspicuously represented in the kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis, with notable upregulation of Heme oxygenase 1 (HMOX1), Ferritin light chain (FTL), and Solute carrier family 3 member 2 (SLC3A2) and downregulation of Scavenger receptor class A member 5 (SCARA5) and glutaminase (GLS). Random selection of DEGs for validation through qRT-PCR corroborated the RNA-Seq data (R2 = 0.93). Kelch like ECH associated protein 1 (Keap1) protein expression decreased after 4 and 8 h, while NFE2 like bZIP transcription factor 2 (Nrf2) and HMOX1 were elevated, with significant nuclear translocation of Nrf2. CONCLUSIONS: The virulence factors of P. gingivalis may potentially instigating ferroptosis through activation of the Keap1-Nrf2-HMOX1 signaling cascade, in conjunction with modulating the expression of other ferroptosis-associated elements. Further research is necessary to achieve a thorough comprehension of these complex molecular interactions.
Subject(s)
Ferroptosis , Human Umbilical Vein Endothelial Cells , Porphyromonas gingivalis , Virulence Factors , Porphyromonas gingivalis/pathogenicity , Porphyromonas gingivalis/genetics , Ferroptosis/genetics , Humans , Virulence Factors/genetics , Up-Regulation , Heme Oxygenase-1/genetics , Heme Oxygenase-1/metabolism , Blotting, Western , Down-Regulation , NF-E2-Related Factor 2/genetics , NF-E2-Related Factor 2/metabolismABSTRACT
Porphyromonas gingivalis (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-1ß 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.
Subject(s)
Blood-Brain Barrier , Extracellular Vesicles , Gingiva , Periodontitis , Porphyromonas gingivalis , Blood-Brain Barrier/metabolism , Animals , Humans , Mice , Extracellular Vesicles/metabolism , Porphyromonas gingivalis/metabolism , Porphyromonas gingivalis/pathogenicity , Periodontitis/microbiology , Periodontitis/metabolism , Periodontitis/pathology , Gingiva/metabolism , Gingiva/microbiology , Mice, Inbred C57BL , Male , Exosomes/metabolism , Female , Bacteroidaceae Infections/microbiology , Bacteroidaceae Infections/metabolismABSTRACT
AIM: Blood-brain barrier (BBB) disorder is one of the early findings in cognitive impairments. We have recently found that Porphyromonas gingivalis bacteraemia can cause cognitive impairment and increased BBB permeability. This study aimed to find out the possible key virulence factors of P. gingivalis contributing to the pathological process. MATERIALS AND METHODS: C57/BL6 mice were infected with P. gingivalis or gingipains or P. gingivalis lipopolysaccharide (P. gingivalis LPS group) by tail vein injection for 8 weeks. The cognitive behaviour changes in mice, the histopathological changes in the hippocampus and cerebral cortex, the alternations of BBB permeability, and the changes in Mfsd2a and Cav-1 levels were measured. The mechanisms of Ddx3x-induced regulation on Mfsd2a by arginine-specific gingipain A (RgpA) in BMECs were explored. RESULTS: P. gingivalis and gingipains significantly promoted mice cognitive impairment, pathological changes in the hippocampus and cerebral cortex, increased BBB permeability, inhibited Mfsd2a expression and up-regulated Cav-1 expression. After RgpA stimulation, the permeability of the BBB model in vitro increased, and the Ddx3x/Mfsd2a/Cav-1 regulatory axis was activated. CONCLUSIONS: Gingipains may be one of the key virulence factors of P. gingivalis to impair cognition and enhance BBB permeability by the Ddx3x/Mfsd2a/Cav-1 axis.
Subject(s)
Blood-Brain Barrier , Gingipain Cysteine Endopeptidases , Mice, Inbred C57BL , Porphyromonas gingivalis , Virulence Factors , Animals , Porphyromonas gingivalis/pathogenicity , Blood-Brain Barrier/microbiology , Mice , Virulence Factors/metabolism , Adhesins, Bacterial/metabolism , Male , Disease Models, Animal , Permeability , Cognitive Dysfunction/microbiology , Cognitive Dysfunction/metabolism , Hippocampus/metabolism , Bacteroidaceae Infections/microbiology , Bacteroidaceae Infections/complicationsABSTRACT
The association between Porphyromonas gingivalis infection and oral squamous cell carcinoma (OSCC) has been established by numerous epidemiological studies. However, the underlying mechanism specific to this connection remains unclear. By bioinformatical analysis, we identified ZFP36 as a potentially significant co-expressed gene in both the OSCC gene database and the persistent infection model of P. gingivalis. To further investigate the role of ZFP36, we established a cell model that human immortalized oral epithelial cells (HIOECs) that were sustainedly infected by P. gingivalis (MOI = 1) for a duration of 30 weeks. Our findings indicated that sustained infection with P. gingivalis inhibited the expression of ZFP36 protein and induced changes in the biological behaviour of HIOECs. The mechanism investigation demonstrated the potential role of ZFP36 in regulating the cancer-related biological behaviour of HIOECs. Subsequent studies revealed that highly expressed CCAT1 could serve as a molecular scaffold in the formation of the ZFP36/CCAT1/MK2 complex. This complex formation enhanced the binding abundance of MK2 and ZFP36, thereby promoting the inhibition of ZFP36 protein phosphorylation. To summarize, low expression of ZFP36 protein under persistent P. gingivalis infection enhances the cancer-related biological behaviour of HIOECs.
Subject(s)
Bacteroidaceae Infections , Epithelial Cells , Porphyromonas gingivalis , Tristetraprolin , Humans , Porphyromonas gingivalis/pathogenicity , Epithelial Cells/microbiology , Epithelial Cells/metabolism , Epithelial Cells/pathology , Bacteroidaceae Infections/microbiology , Bacteroidaceae Infections/metabolism , Tristetraprolin/metabolism , Tristetraprolin/genetics , Mouth Neoplasms/pathology , Mouth Neoplasms/microbiology , Mouth Neoplasms/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Intracellular Signaling Peptides and Proteins/genetics , Carcinoma, Squamous Cell/pathology , Carcinoma, Squamous Cell/metabolism , Carcinoma, Squamous Cell/microbiology , Carcinogenesis/metabolism , Carcinogenesis/pathology , PhosphorylationABSTRACT
Bacteremia induced by periodontal infection is an important factor for periodontitis to threaten general health. P. gingivalis DNA/virulence factors have been found in the brain tissues from patients with Alzheimer's disease (AD). The blood-brain barrier (BBB) is essential for keeping toxic substances from entering brain tissues. However, the effect of P. gingivalis bacteremia on BBB permeability and its underlying mechanism remains unclear. In the present study, rats were injected by tail vein with P. gingivalis three times a week for eight weeks to induce bacteremia. An in vitro BBB model infected with P. gingivalis was also established. We found that the infiltration of Evans blue dye and Albumin protein deposition in the rat brain tissues were increased in the rat brain tissues with P. gingivalis bacteremia and P. gingivalis could pass through the in vitro BBB model. Caveolae were detected after P. gingivalis infection in BMECs both in vivo and in vitro. Caveolin-1 (Cav-1) expression was enhanced after P. gingivalis infection. Downregulation of Cav-1 rescued P. gingivalis-enhanced BMECs permeability. We further found P. gingivalis-gingipain could be colocalized with Cav-1 and the strong hydrogen bonding between Cav-1 and arg-specific-gingipain (RgpA) were detected. Moreover, P. gingivalis significantly inhibited the major facilitator superfamily domain containing 2a (Mfsd2a) expression. Mfsd2a overexpression reversed P. gingivalis-increased BMECs permeability and Cav-1 expression. These results revealed that Mfsd2a/Cav-1 mediated transcytosis is a key pathway governing BBB BMECs permeability induced by P. gingivalis, which may contribute to P. gingivalis/virulence factors entrance and the subsequent neurological impairments.
Subject(s)
Bacteremia , Blood-Brain Barrier , Caveolin 1 , Porphyromonas gingivalis , Animals , Rats , Bacteremia/complications , Bacteremia/metabolism , Blood-Brain Barrier/metabolism , Blood-Brain Barrier/microbiology , Caveolin 1/metabolism , Gingipain Cysteine Endopeptidases/metabolism , Permeability , Porphyromonas gingivalis/pathogenicity , Transcytosis , Virulence Factors/metabolismABSTRACT
Bacteremia induced by periodontal infection is an important factor for periodontitis to threaten general health. P. gingivalis DNA/virulence factors have been found in the brain tissues from patients with Alzheimer's disease (AD). The blood-brain barrier (BBB) is essential for keeping toxic substances from entering brain tissues. However, the effect of P. gingivalis bacteremia on BBB permeability and its underlying mechanism remains unclear. In the present study, rats were injected by tail vein with P. gingivalis three times a week for eight weeks to induce bacteremia. An in vitro BBB model infected with P. gingivalis was also established. We found that the infiltration of Evans blue dye and Albumin protein deposition in the rat brain tissues were increased in the rat brain tissues with P. gingivalis bacteremia and P. gingivalis could pass through the in vitro BBB model. Caveolae were detected after P. gingivalis infection in BMECs both in vivo and in vitro. Caveolin-1 (Cav-1) expression was enhanced after P. gingivalis infection. Downregulation of Cav-1 rescued P. gingivalis-enhanced BMECs permeability. We further found P. gingivalis-gingipain could be colocalized with Cav-1 and the strong hydrogen bonding between Cav-1 and arg-specific-gingipain (RgpA) were detected. Moreover, P. gingivalis significantly inhibited the major facilitator superfamily domain containing 2a (Mfsd2a) expression. Mfsd2a overexpression reversed P. gingivalis-increased BMECs permeability and Cav-1 expression. These results revealed that Mfsd2a/Cav-1 mediated transcytosis is a key pathway governing BBB BMECs permeability induced by P. gingivalis, which may contribute to P. gingivalis/virulence factors entrance and the subsequent neurological impairments.
Subject(s)
Animals , Rats , Bacteremia/metabolism , Blood-Brain Barrier/microbiology , Caveolin 1/metabolism , Gingipain Cysteine Endopeptidases/metabolism , Permeability , Porphyromonas gingivalis/pathogenicity , Transcytosis , Virulence Factors/metabolismABSTRACT
Introducción: Porphyromonas gingivalis es un microorganismo presente en las periodontitis, productor de la enzima peptidil arginina desminasa, inductora de la citrulinación de proteínas que convierte en antígenos, y que son reconocidos por los anticuerpos antipéptido cíclico citrulinados, marcadores específicos de la artritis reumatoide. Estudios clínicos y epidemiológicos relacionan el hábito de fumar con la periodontitis y la artritis reumatoide. Objetivo: Evaluar la asociación entre el hábito de fumar, la periodontitis crónica y la artritis reumatoide. Métodos: Se realizó un estudio observacional, analítico, de corte transversal, de casos y controles de pacientes con diagnóstico de artritis reumatoide tratados en el Centro de Reumatología y pacientes atendidos por medicina interna en el Hospital Clínico Quirúrgico 10 de octubre de La Habana, en el periodo entre septiembre del 2017 y mayo del 2019. Se estudiaron las variables edad, sexo, hábito de fumar y estado periodontal evaluado a través del índice de enfermedad periodontal de Russell y el nivel de inserción clínica. Para identificar la asociación entre variables se empleó la prueba de ji al cuadrado y el odds ratio. Se respetaron las legislaciones éticas. Resultados: En el estudio prevaleció el grupo de 35 a 44 años y el sexo femenino. El hábito de fumar predominó en los pacientes artríticos, con manifiesto incremento de la prevalencia y gravedad de la enfermedad periodontal. Conclusiones: El hábito de fumar incrementó el riesgo de periodontitis crónica en ambos grupos, y con menos intensidad de riesgo en la artritis reumatoide.
Introduction: Porphyromonas gingivalis is a microorganism present in periodontitis, producer of the enzyme peptidyl arginine deminase that induces citrullination of proteins, turning them into antigens, which are recognized by anti-citrullinated cyclic peptide antibodies, specific markers of rheumatoid arthritis. Clinical and epidemiological studies link smoking with periodontitis and rheumatoid arthritis. Objective: To evaluate the association between smoking, the presence of chronic periodontitis and rheumatoid arthritis. Methods: An observational, analytical, cross-sectional study of cases and controls of patients with a diagnosis of rheumatoid arthritis treated at the Rheumatology Center and patients treated by Internal Medicine in 10 de Octubre Surgical- Clinic Hospital in Havana, between September 2017 and May 2019. The variables were: age, sex, smoking habit and periodontal status evaluated through the Russell Periodontal Disease Index and Level of Clinical Insertion. For the association and relationship between variables, the chi square and the odds ratio were used. Ethical legislation was respected. Results: In the study the group of 35 to 44 years old and the female sex prevailed. Smoking prevailed in arthritic patients with a remarkable increase in the prevalence and severity of periodontal disease. Conclusions: Smoking increased the risk of chronic periodontitis in both groups with less intensity of risk in rheumatoid arthritis.
Subject(s)
Female , Adult , Arthritis, Rheumatoid/complications , Smoking/adverse effects , Porphyromonas gingivalis/pathogenicity , Chronic Periodontitis/complicationsABSTRACT
Porphyromonas gingivalis is a gram-negative oral anaerobic pathogen and is one of the key causative agents of periodontitis. P. gingivalis utilises a range of virulence factors, including the cysteine protease RgpB, to drive pathogenesis and these are exported and attached to the cell surface via the type IX secretion system (T9SS). All cargo proteins possess a conserved C-terminal signal domain (CTD) which is recognised by the T9SS, and the outer membrane ß-barrel protein PorV (PG0027/LptO) can interact with cargo proteins as they are exported to the bacterial surface. Using a combination of solution nuclear magnetic resonance (NMR) spectroscopy, biochemical analyses, machine-learning-based modelling and molecular dynamics (MD) simulations, we present a structural model of a PorV:RgpB-CTD complex from P. gingivalis. This is the first structural insight into CTD recognition by the T9SS and shows how the conserved motifs in the CTD are the primary sites that mediate binding. In PorV, interactions with extracellular surface loops are important for binding the CTD, and together these appear to cradle and lock RgpB-CTD in place. This work provides insight into cargo recognition by PorV but may also have important implications for understanding other aspects of type-IX dependent secretion.
Subject(s)
Bacterial Proteins , Bacterial Secretion Systems , Membrane Proteins , Molecular Dynamics Simulation , Porphyromonas gingivalis , Bacterial Proteins/chemistry , Membrane Proteins/chemistry , Porphyromonas gingivalis/metabolism , Porphyromonas gingivalis/pathogenicity , Virulence Factors/chemistry , Bacterial Secretion Systems/chemistry , Protein DomainsABSTRACT
BACKGROUND/AIMS: Interleukin 33 (IL-33) plays a significant role in immunity but its role in bone physiology and periodontitis needs to be further investigated. The aim of this study was to decipher the contribution of IL-33 to bone homeostasis under physiological conditions, and to alveolar bone loss associated with experimental periodontitis (EP) in IL-33 knockout (KO) mice and their wildtype (WT) littermates. METHODS: The bone phenotype of IL-33 KO mice was studied in the maxilla, femur, and fifth lumbar vertebra by micro-computed tomography (micro-CT). EP was induced by a ligature soaked with the periopathogen Porphyromonas gingivalis (Pg) around a maxillary molar. Alveolar bone loss was quantified by micro-CT. The resorption parameters were assessed via toluidine blue staining on maxillary sections. In vitro osteoclastic differentiation assays using bone marrow cells were performed with or without lipopolysaccharide from Pg (LPS-Pg). RESULTS: First, we showed that under physiological conditions, IL-33 deficiency increased the trabecular bone volume/total volume ratio (BV/TV) of the maxillary bone in male and female mice, but not in the femur and fifth lumbar vertebra, suggesting an osteoprotective role for IL-33 in a site-dependent manner. The severity of EP induced by Pg-soaked ligature was increased in IL-33 KO mice but in female mice only, through an increase in the number of osteoclasts. Moreover, osteoclastic differentiation from bone marrow osteoclast progenitors in IL-33-deficient female mice is enhanced in the presence of LPS-Pg. CONCLUSION: Taken together, our data demonstrate that IL-33 plays a sex-dependent osteoprotective role both under physiological conditions and in EP with Pg.
Subject(s)
Alveolar Bone Loss , Interleukin-33 , Periodontitis , Alveolar Bone Loss/microbiology , Animals , Female , Interleukin-33/deficiency , Interleukin-33/genetics , Lipopolysaccharides , Male , Mice , Mice, Knockout , Osteoclasts , Periodontitis/microbiology , Porphyromonas gingivalis/pathogenicity , X-Ray MicrotomographyABSTRACT
Serum- and glucocorticoid-regulated kinase 1 (SGK1) is a serine/threonine kinase that plays important roles in the cellular stress response. While SGK1 has been reported to restrain inflammatory immune responses, the molecular mechanisms involved remain elusive, especially in oral bacteria-induced inflammatory milieu. Here, we found that SGK1 curtails Porphyromonas gingivalis-induced inflammatory responses through maintaining levels of tumor necrosis factor receptor-associated factor (TRAF) 3, thereby suppressing NF-κB signaling. Specifically, SGK1 inhibition significantly enhances production of proinflammatory cytokines, including tumor necrosis factor α, interleukin (IL)-6, IL-1ß, and IL-8 in P. gingivalis-stimulated innate immune cells. The results were confirmed with siRNA and LysM-Cre-mediated SGK1 KO mice. Moreover, SGK1 deletion robustly increased NF-κB activity and c-Jun expression but failed to alter the activation of mitogen-activated protein kinase signaling pathways. Further mechanistic data revealed that SGK1 deletion elevates TRAF2 phosphorylation, leading to TRAF3 degradation in a proteasome-dependent manner. Importantly, siRNA-mediated traf3 silencing or c-Jun overexpression mimics the effect of SGK1 inhibition on P. gingivalis-induced inflammatory cytokines and NF-κB activation. In addition, using a P. gingivalis infection-induced periodontal bone loss model, we found that SGK1 inhibition modulates TRAF3 and c-Jun expression, aggravates inflammatory responses in gingival tissues, and exacerbates alveolar bone loss. Altogether, we demonstrated for the first time that SGK1 acts as a rheostat to limit P. gingivalis-induced inflammatory immune responses and mapped out a novel SGK1-TRAF2/3-c-Jun-NF-κB signaling axis. These findings provide novel insights into the anti-inflammatory molecular mechanisms of SGK1 and suggest novel interventional targets to inflammatory diseases relevant beyond the oral cavity.
Subject(s)
Alveolar Bone Loss , Immediate-Early Proteins , Protein Serine-Threonine Kinases , TNF Receptor-Associated Factor 3 , Alveolar Bone Loss/genetics , Animals , Cytokines/metabolism , Genes, jun , Immediate-Early Proteins/metabolism , Immunity , Inflammation , Mice , NF-kappa B/genetics , NF-kappa B/metabolism , Porphyromonas gingivalis/pathogenicity , Protein Serine-Threonine Kinases/metabolism , RNA, Small Interfering , Signal Transduction , TNF Receptor-Associated Factor 2/metabolism , TNF Receptor-Associated Factor 3/metabolismABSTRACT
AIM: The aim of this study was to evaluate the effect of the administration of pasteurized Akkermansia muciniphila and Amuc_1100 on periodontal destruction in lean and obese mice and to determine the impact of the mode of administration. MATERIALS AND METHODS: Porphyromonas gingivalis-associated experimental periodontitis was induced in lean and obese mice. After 3 weeks, live, pasteurized A. muciniphila or Amuc_1100 was administered by oral or gastric gavage for three additional weeks. Moreover, an evaluation of the interaction between A. muciniphila and P. gingivalis was performed by RNA-sequencing, and cytokines secretion was measured in exposed macrophages. RESULTS: Oral administration of live, pasteurized A. muciniphila or Amuc_1100 significantly decreased P. gingivalis-induced periodontal destruction and inflammatory infiltrate in lean and obese mice and contributed to the reduction of the plasma level of TNF-α and to the increase of IL-10. The co-culture of A. muciniphila and P. gingivalis induced an increased expression of genes linked to the synthesis of monobactam-related antibiotics in A. muciniphila, while a decrease of the gingipains and type IX secretion system was observed in P. gingivalis. In P. gingivalis-infected macrophages, pasteurized A. muciniphila decreased TNF-α and increased IL-10 levels. CONCLUSIONS: Pasteurized A. muciniphila can counteract P. gingivalis-associated periodontal destruction.