Project description:Periodontitis increases the risk of non-alcoholic fatty liver disease (NAFLD). However, the precise mechanisms are unclear. Here, gut dysbiosis induced by orally administered Porphyromonas gingivalis, a representative periodontopathic bacterium, was implicated in the deterioration of NAFLD pathology. C57BL/6 mice were administered with the vehicle, P. gingivalis or Prevotella intermedia, with weaker periodontal pathogenicity, followed by feeding on a choline-deficient, high fat diet (CDAHFD60). CDAHFD60 feeding induced hepatic steatosis, and combined bacterial administration further aggravated NAFLD pathology with increased fibrosis. Liver gene expression analyses revealed that genes involved in the NAFLD pathology were perturbed with distinctive expression profiles induced by different bacteria. These differences may be due to quantitative and qualitative differences in the influx of gut bacterial products because the serum endotoxin level, gut microbiota composition, and serum metabolite profile caused by ingested P. intermedia and P. gingivalis were different. These findings provide insights into mechanisms linking periodontitis and NAFLD.
Project description:The outer membrane vesicles (OMVs) produced by Porphyromonas gingivalis (P. gingivalis) contain a variety of bioactive molecules that may be involved in the progression of periodontitis. However, the participation of P. gingivalis OMVs in the development of periodontitis has not been elucidated. Here we isolated P. gingivalis OMVs and confirmed their participation in periodontitis both in vivo and in vitro. Microcomputed Tomography (micro-CT) and histological analysis showed that under the stimulation of P. gingivalis OMVs, the alveolar bone of rats was significantly resorbed in vivo. We found that P. gingivalis OMVs were taken up by hPDLCs (human Periodontal Ligament Cells, hPDLCs) in vitro, then subsequently resulting in apoptosis and inflammatory cytokines releasing which was accomplished by the microRNA-size small RNAs (msRNAs) sRNA45033 in the P. gingivalis OMVs. Through bioinformatics analysis and screening of target genes, Chromobox 5 (CBX5) was identified as the downstream target of screened-out small RNA s45033. Using dual-luciferase reporter assay, overexpression, and knockdown methods, s45033 was confirmed to target CBX5 to regulate hPDLCs apoptosis. In addition, Cleavage Under Targets and Tagmentation (Cut&Tag) analysis confirmed the mechanism that CBX5 regulates apoptosis through the methylation of p53 DNA. Collectively, these findings indicate that the role of P. gingivalis OMVs is immunologically relevant and related to bacterial virulence in the development of periodontitis.
Project description:Porphyromonas gingivalis (P. gingivalis) is a key pathogen in periodontitis. Our previous study indicated that periodontitis induced by P. gingivalis increases the percentage of CD19+ B cells, Th17, Treg, gMDSCs and mMDSCs but decreases the ratio of B10 cells in CIA mice. It’s unclear which virulence factors of P. gingivalis are involved in these processes. Here, our study first indicated that such effects are 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 strain of P. gingivalis (ATCC33277) with its isogenic gingipain-null mutant (△K△RAB) on B cells. The results showed that B cells infected with △K△RAB exhibited increased levels of IL-6 and others cytokines (IL-1β,IL-23) involve in Th17 differentiation compared to wild-type strain, also the frequency of IL-10 producing regulatory B cells (B10). Furthermore, the peritonitis induced by △K△RAB enhanced the proportion of B10 and Th17 compared with treated with ATCC33277. Cumulatively, this study preliminarily revealed deletion of gingipains affected the antigen presentation of B cell that promoted B cells express the cytokines which promoted T cells toward Th17 and the secretion immunosuppressive cytokines of B cells that enhanced the frequency of B10 which implicated gingipains are vital in altering B cell function to participated immune response.
Project description:Porphyromonas gingivalis is a gram-negative bacterium that causes destructive chronic periodontitis. In addition, this bacterium is also involved in the development of cardiovascular disease. The aim of this study was to investigate the effects of P. gingivalis infection on gene and protein expression in human aortic smooth muscle cells (AoSMCs) and its relation to cellular function.
Project description:Porphyromonas gingivalis secretes cysteine proteases named gingipains which can cleave an array of proteins and importantly contribute to the development of periodontitis. In this study we focused on gingipain-exerted proteolysis at the cell surface of human gingival epithelial cells (telomerase immortalized gingival keratinocytes [TIGK]). We examined whether gingipains have sheddase activity or if their main activity is degradation of membrane proteins into small fragments. Using mass spectrometry, we investigated the whole sheddome/degradome of TIGK cell surface proteins by P. gingivalis strains differing in gingipain expression. We observed extensive degradation of TIGK surface proteins, suggesting that gingipains could in fact be the major cause of damage to the gingival epithelium. Most of the identified gingipain substrates were molecules involved in adhesion, suggesting that gingipains may cause tissue damage through cleavage of cell contacts, resulting in cell detachment and rounding, and consequently leading to anoikis. These results reveal a molecular underpinning to P. gingivalis-induced tissue destruction and enhance our knowledge of the role of P. gingivalis’ proteases in the pathobiology of periodontitis.
Project description:Investigation of whole genome gene expression level changes in Porphyromonas gingivalis ATCC 33277 treated with an anti-adhesive extract from Myrothamnus flabellifolia compared to the untreated strain. Aim: Identification of anti-adhesive plant extracts against cell surface binding of Porphyromonas gingivalis. Materials and Methods: Polyphenol-enriched extract from Myrothamnus flabellifolia (MF) traditionally used for periodontitis was tested for inhibition of P. gingivalis adhesion to KB cells by FACS, for influence on gingipain activity, hemagglutination and by microarray analysis for effects on the bacterial transcriptome. P. gingivalis-induced inflammation parameters were monitored by RT-PCR. Results: MF (100 µg/ml) reduced P. gingivalis adhesion/invasion about 50% by interacting with fimbriae and bacterial OMPs. Microarray analysis of MF-treated bacteria indicated up-regulation of genes involved in cell adhesion. As confirmed by RT-PCR, fimbrillin- and Arg-gingipain-encoding genes were upregulated by MF. On the protein level, inhibition (70%) of Arg-gingipain activity was observed, while the corresponding Lys-gingipain was hardly influenced. MF also inhibited hemagglutination. While exposure to P. gingivalis resulted in an increased expression of inflammation-related genes in KB cells, pretreatment of KB cells with MF evoked cytoprotective effects concerning IL-1β, IL-6, IL-8 and TNFα gene expression as well as IL-6 release rates. Conclusions: While being cytoprotective, MF exerts strong anti-adhesive effects against P. gingivalis. Thus, MF may be useful for the prevention of P. gingivalis-associated periodontal diseases. The chip study used total RNA recovered from two separate MF-treated and two separate untreated Porphyromonas gingivalis ATCC 33277 cultures. Each chip measured the expression level of 1,842 genes from P. gingivalis ATCC 33277 with thirteen 60-mer probes per gene, with three-fold technical redundancy.
Project description:Rheumatoid arthritis (RA) and periodontitis (PD) are chronic inflammatory diseases that appear to occur in tandem. Autoantibodies against citrullinated peptide antigens linked pathogeneses with PD preceding RA. However, the mutual impact PD exerts on RA and vice versa has not yet been defined. To address this issue, we set up an animal model and analyzed how the prime inducers of citrullination - Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans – differ in their pathogenic potential. Our experimental setup included collagen induced arthritis (CIA) in the mouse, oral inoculation with P. gingivalis or A. actinomycetemcomitans to induce alveolar bone loss and the combination of both diseases in inverted orders of events. Label-free quantitative proteome analysis revealed that P. gingivalis and A. actinomycetemcomitans led to differential expression patterns in the synovial membranes that were reminiscent of cellular and humoral immune responses, respectively. The P. gingivalis and A. actinomycetemcomitans specific signatures in the synovial proteomes suggest a role for oral pathogens in shaping disease subtypes and setting the stage for subsequent therapy response.
Project description:Periodontitis and infections with periodontal bacteria have been highlighted as risk factors for dementia. In recent years attention has been drawn to the role of microglia cells in neurodegenerative diseases. However, there is limited knowledge of the influence of periodontal bacteria on microglia cells. The aim of the present study was to investigate the interactions between the periodontal bacteria P. gingivalis and microglia cells, and to unravel if these interactions could contribute to Alzheimer’s pathology. Periodontitis and infections with periodontal bacteria have been highlighted as risk factors for dementia. In recent years attention has been drawn to the role of microglia cells in neurodegenerative diseases. However, there is limited knowledge of the influence of periodontal bacteria on microglia cells. The aim of the present study was to investigate the interactions between the periodontal bacteria P. gingivalis and microglia cells, and to unravel if these interactions could contribute to Alzheimer’s pathology. We found, through microarray analysis, that stimulation of microglia cells with P. gingivalis resulted in upregulation of several Alzheimer´s disease associated genes, including NOX4. We also showed that P. gingivalis LPS mediated ROS production and IL-6 and IL-8 induction via NOX4 in microglia. The viability of neurons was shown to be reduced by conditioned media from microglia cells stimulated with P. gingivalis LPS, and that the reduction was NOX4 dependent. The levels of total and phosphorylated Tau in neurons were increased by conditioned media from microglia cells stimulated with P. gingivalis or LPS. This increase was NOX4 dependent. In summary our findings give us a potential mechanistic explanation of how the periodontal pathogen P. gingivalis could trigger or exacerbate AD pathogenesis.