Modulation de l'expression de gènes reliés à la virulence et au stress chez Porphyromonas gingivalis par les polyphénols du thé vert

Dans ce projet, la capacité des polyphénols du thé vert à moduler l’expression de certains gènes chez Porphyromonas gingivalis, le principal agent étiologique de la parodontite chronique, a été évaluée. Une analyse par PCR quantitative a démontré qu’à des concentrations sous-inhibitrices, l’extrait de thé vert ainsi que l’épigallocatéchine-3-gallate (EGCG) réduisent à différents degrés le niveau d’expression de gènes codant pour d’importants facteurs de virulence chez P. gingivalis. Ces facteurs participent notamment à la colonisation, l’acquisition des nutriments et la destruction tissulaire. De plus, les deux composés ont augmenté le niveau d’expression du gène codant pour la protéine de résistance au stress HtrA chez P. gingivalis. Les résultats de cette étude suggèrent que le thé vert et l’EGCG pourraient contribuer à réduire la virulence de P. gingivalis, supportant ainsi une potentielle utilisation pour la prévention et le traitement de la parodontite

Anti-Bacterial and Anti-Inflammatory Properties of Daiokanzoto

Kampo formulations used in Japan to treat a wide variety of diseases and to promote health are composed of mixtures of crude extracts from the roots, bark, leaves, and rhizomes of a number of herbs. The present study was aimed at identifying the beneficial biological properties of Daiokanzoto (TJ-84), a Kampo formulation composed of crude extracts of Rhubarb rhizomes and Glycyrrhiza roots, with a view to using it as a potential treatment for periodontal disease. Daiokanzoto dose-dependently inhibited the expression of major Porphyromonas gingivalis virulence factors involved in host colonization and tissue destruction. More specifically, Daiokanzoto reduced the expression of the fimA, hagA, rgpA, and rgpB genes, as determined by quantitative real-time PCR. The U937-3xκB-LUC monocyte cell line transfected with a luciferase reporter gene was used to evaluate the anti-inflammatory properties of Daiokanzoto. Daiokanzoto attenuated the P. gingivalis-mediated activation of the NF-κB signaling pathway. It also reduced the secretion of pro-inflammatory cytokines (IL-6 and CXCL8) by lipopolysaccharide-stimulated oral epithelial cells and gingival fibroblasts. Lastly, Daiokanzoto, dose-dependently inhibited the catalytic activity of matrix metalloproteinases (-1 and -9). In conclusion, the present study provided evidence that Daiokanzoto shows potential for treating and/or preventing periodontal disease. The ability of this Kampo formulation to act on both bacterial pathogens and the host inflammatory response, the two etiological components of periodontal disease, is of high therapeutic interest

Identification of dichloroacetic acid degrading Cupriavidus bacteria in a drinking water distribution network model

Aims: Bacterial community structure and composition of a drinking water network were assessed to better understand this ecosystem in relation to haloacetic acid (HAA) degradation and to identify new bacterial species having HAA degradation capacities. Methods and Results: Biofilm samples were collected from a model system, simulating the end of the drinking water distribution network and supplied with different concentrations of dichloroacetic and trichloroacetic acids at different periods over the course of a year. The samples were analysed by culturing, denaturing gradient gel electrophoresis (DGGE) and sequencing. Pipe diameter and HAA ratios did not impact the bacterial community profiles, but the season had a clear influence. Based on DGGE profiles, it appeared that a particular biomass has developed during the summer compared with the other seasons. Among the bacteria isolated in this study, those from genus Cupriavidus were able to degrade dichloroacetic acid. Moreover, these bacteria degrade dichloroacetic acid at 18°C but not at 10°C. Conclusions: The microbial diversity evolved throughout the experiment, but the bacterial community was distinct during the summer. Results obtained on the capacity of Cupriavidus to degrade DCAA only at 18°C but not at 10°C indicate that water temperature is a major element affecting DCAA degradation and confirming observations made regarding season influence on HAA degradation in the drinking water distribution network. Significance and Impact of the Study: This is the first demonstration of the HAA biodegradation capacity of the genus Cupriavidu

The Daiokanzoto (TJ-84) Kampo Formulation Reduces Virulence Factor Gene Expression in Porphyromonas gingivalis and Possesses Anti-Inflammatory and Anti-Protease Activities.

Kampo formulations used in Japan to treat a wide variety of diseases and to promote health are composed of mixtures of crude extracts from the roots, bark, leaves, and rhizomes of a number of herbs. The present study was aimed at identifying the beneficial biological properties of Daiokanzoto (TJ-84), a Kampo formulation composed of crude extracts of Rhubarb rhizomes and Glycyrrhiza roots, with a view to using it as a potential treatment for periodontal disease. Daiokanzoto dose-dependently inhibited the expression of major Porphyromonas gingivalis virulence factors involved in host colonization and tissue destruction. More specifically, Daiokanzoto reduced the expression of the fimA, hagA, rgpA, and rgpB genes, as determined by quantitative real-time PCR. The U937-3xκB-LUC monocyte cell line transfected with a luciferase reporter gene was used to evaluate the anti-inflammatory properties of Daiokanzoto. Daiokanzoto attenuated the P. gingivalis-mediated activation of the NF-κB signaling pathway. It also reduced the secretion of pro-inflammatory cytokines (IL-6 and CXCL8) by lipopolysaccharide-stimulated oral epithelial cells and gingival fibroblasts. Lastly, Daiokanzoto, dose-dependently inhibited the catalytic activity of matrix metalloproteinases (-1 and -9). In conclusion, the present study provided evidence that Daiokanzoto shows potential for treating and/or preventing periodontal disease. The ability of this Kampo formulation to act on both bacterial pathogens and the host inflammatory response, the two etiological components of periodontal disease, is of high therapeutic interest

Effect of Daiokanzoto on the expression of <i>fimA</i> and <i>hagA</i> (Panel A) and <i>rgpA</i> and <i>rgpB</i> mRNA (Panel B) in <i>P</i>. <i>gingivalis</i>.

<p>Data are expressed as means ± standard deviations. mRNA expression was normalized to 16S rRNA. *, significantly different (P < 0.01) compared to an untreated control.</p

Effect of Daiokanzoto on <i>P</i>. <i>gingivalis</i>-induced activation of the NF-κB signaling pathway in monocytes.

<p>Data are expressed as means ± standard deviations. *, Significant inhibition at <i>p</i> < 0.01 using a Student’s <i>t</i>-test.</p

Effect of Daiokanzoto on IL-6 (Panel A) and CXCL8 (Panel B) secretion by LPS-stimulated human oral epithelial cells (OBA-9).

<p>Data are expressed as means ± standard deviations. *, Significant inhibition at <i>p</i> < 0.01 using a Student’s <i>t</i>-test.</p

Effect of Daiokanzoto on IL-6 (Panel A) and CXCL8 (Panel B) secretion by LPS-stimulated human gingival fibroblasts (HGF-1).

<p>Data are expressed as means ± standard deviations. *, Significant inhibition at <i>p</i> < 0.01 using a Student’s <i>t</i>-test.</p

Green tea extract and its major constituent epigallocatechin-3-gallate inhibit growth and halitosis-related properties of Solobacterium moorei

Background: Solobacterium moorei is a volatile sulfide compound (VSC)-producing Gram-positive anaerobic bacterium that has been associated with halitosis. The aim of this study was to investigate the effects of green tea extract and its major constituent epigallocatechin-3-gallate (EGCG) on growth and severalhalitosis-related properties of S. moorei.Methods: A microplate dilution assay was used to determine the antibacterial activity of green tea extract and EGCG against S. moorei. Their effects on bacterial cell membrane integrity were investigated by transmission electron microscopy and a fluorescence-based permeability assay. Biofilm formation was quantified by crystal violet staining. Adhesion of FITC-labeled S. moorei to oral epithelial cells was monitored by fluorometry. The modulation of beta-galactosidase gene expression in S. moorei was evaluated by quantitative RT-PCR.Results: The green tea extract as well as EGCG inhibited the growth of S. moorei, with MIC values of 500 and 250 mu g/ml, respectively. Transmission electron microscopy analysis and a permeabilization assay brought evidence that the bacterial cell membrane was the target of green tea polyphenols. Regarding the effects of green tea polyphenols on the S. moorei colonization properties, it was found that biofilm formation on EGCG-treated surfaces was significantly affected, and that green tea extract and EGCG can cause the eradication of pre-formed S. moorei biofilms. Moreover, both the green tea extract and EGCG were found to reduce the adherence of S. moorei to oral epithelial cells. The beta-galactosidase activity of S. moorei, which plays a key role in VSC production, was dose-dependently inhibited by green tea polyphenols. In addition, EGCG at 1/2 MIC significantly decreased the beta-galactosidase gene expression.Conclusion: Our study brought evidence to support that green tea polyphenols possess a number of properties that may contribute to reduce S. moorei-related halitosis. Therefore, these natural compounds may be of interest to be used to supplement oral healthcare products

Primers used for the quantitative RT-PCR analysis of virulence factor gene expression in <i>P</i>. <i>gingivalis</i>.

<p>Primers used for the quantitative RT-PCR analysis of virulence factor gene expression in <i>P</i>. <i>gingivalis</i>.</p