BACKGROUND: Periodontitis is characterized by alveolar bone resorption, aggravated by osteoblast dysfunction, and associated with intracellular oxidative stress linked to the nuclear factor erythroid 2-related factor 2 (NRF2) level. We evaluated the molecular mechanism of periodontitis onset and development and the role of NRF2 in osteogenic differentiation. METHODS: Primary murine mandibular osteoblasts were extracted and exposed to Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) or other stimuli. Reactive oxygen species (ROS) and 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide (JC-1) staining were used to detect intracellular oxidative stress. Alkaline phosphatase staining and alizarin red S staining were used to detect the osteogenic differentiation of osteoblasts. Immunofluorescence and western blotting were used to determine the changes in the mitogen-activated protein kinase (MAPK) pathway and related molecule activities. Immunofluorescence colocalization and co-immunoprecipitation were performed to examine the nuclear translocation of NRF2 and its interaction with dual-specific phosphatase 1 (DUSP1) in cells. RESULTS: Ligated tissue samples showed higher alveolar bone resorption rate and lower NRF2 level than healthy periodontal tissue samples. Pg-LPS increased intracellular oxidative stress levels and inhibited osteogenic differentiation, whereas changes in NRF2 expression were correlated with changes in the oxidative stress and osteogenesis rate. NRF2 promoted the dephosphorylation of the MAPK pathway by nuclear translocation and the upregulation of DUSP1 expression, thus enhancing the osteogenic differentiation capacity of mandibular osteoblasts. The interaction between NRF2 and DUSP1 was observed. CONCLUSIONS: NRF2 and its nuclear translocation can regulate the osteogenic differentiation of mandibular osteoblasts under Pg-LPS conditions by interacting with DUSP1 in a process linked to the MAPK pathway. These findings form the basis of periodontitis treatment.
Animals ; NF-E2-Related Factor 2/physiology* ; Lipopolysaccharides/pharmacology* ; Osteoblasts/drug effects* ; Mice ; Porphyromonas gingivalis/chemistry* ; Cell Differentiation ; Osteogenesis ; Dual Specificity Phosphatase 1/metabolism* ; Mandible/cytology* ; Reactive Oxygen Species/metabolism* ; Oxidative Stress ; Periodontitis/metabolism* ; Cells, Cultured ; Male ; Cell Nucleus/metabolism*

OBJECTIVE: This study aims to use Arginine-gingipain A gene vaccine (pVAX1-rgpA) to immunize adult Beagle dogs and to evaluate its effect during peri-implantitis progression and development. METHODS: Plasmid pVAX1-rgpA was constructed. The second and third bilateral mandible premolars of 15 adult Beagle dogs were extracted, and the implants were placed immediately. After 3 months, the animals were randomly divided into groups A, B, and C. Afterward, the animals were immunized thrice with plasmid pVAX1-rgpA, with heat-killed Porphyromonas gingivalis, or pVAX1, respectively. IgG in the serum and secretory IgA (sIgA) in saliva were quantitatively analyzed by enzyme-linked immunosorbent assay before and after 2 weeks of immunization. Peri-implantitis was induced with cotton ligatures fixed around the neck of implants. Probing depth (PD) and bleeding on probing were recorded. All animals were sacrificed after ligaturation for 6 weeks. Decalcified sections with thickness of 50 μm were prepared and dyed with methylene blue to observe the bone phenotype around implants. RESULTS: Levels of serum IgG and sIgA in saliva were higher in groups A and B after immunization than before the process (P<0.05) and higher than those in group C (P<0.05). However, no difference was observed between groups A and B (P>0.05). At 4 and 6 weeks after ligaturation, PD of the ligatured side in group C was higher than that in groups A and B (P<0.05). On the other hand, no difference was identified between groups A and B (P>0.05). Bone loss in group A was significantly lower than that of the other groups (P<0.05). Abundant inflammatory cells and bacteria were present in the bone loss area around the implants in the three groups, as identified through hard tissue section observation. However, group C presented the most number of inflammatory cells and bacteria in the bone loss area around the implants. CONCLUSIONS IgG and sIgA can be generated by immunity with rgpA DNA vaccine, which can significantly slow down bone loss during experimental peri-implantitis in dogs.
Adhesins, Bacterial ; therapeutic use ; Alveolar Bone Loss ; Animals ; Arginine ; Cysteine Endopeptidases ; therapeutic use ; Dental Implants ; Dogs ; Peri-Implantitis ; prevention & control ; Porphyromonas gingivalis ; chemistry ; Vaccines ; therapeutic use

OBJECTIVETo test whether Porphyromonas gingivalis (P. gingivalis) could produce bacterial signal molecule, bis-(3'-5')-cyclic dimeric adenosine monophosphate (c-di-AMP) and lay the foundation for explorations of its roles in life metabolism and periodontitis immunity of P. gingivalis.

METHODSP. gingivalis standard strain ATCC33277 was used as the experimental strain to extract nucleic acids from the bacteria. Then, c-di-AMP was detected using high performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS). Subsequently, HPLC was used to validate the sample further.

RESULTSBased on the signal/noise (S/N) for 3 : 1, the limit of determination of HPLC-MS/MS for peak time of c-di-AMP standard substances was 7.49 min and nucleic acid extractions from P. gingivalis was 8.82 min (S/N > 3). Further confirmation of HPLC showed that nucleic acid extractions from both P. gingivalis and c-di-AMP standard substances pre- sented goal absorbent peaks at 15.7 min, with the same ultraviolet absorbent spectrum.

CONCLUSIONThe nucleic acid extrac- tions from P. gingivalis contained c-di-AMP, which shows that P. gingivalis could produce c-di-AMP.

Chromatography, High Pressure Liquid ; Cyclic AMP ; chemistry ; metabolism ; Periodontitis ; Porphyromonas gingivalis ; metabolism ; Tandem Mass Spectrometry

In the present study, two new limonoids, 1α, 7α-dihydroxyl-3α-acetoxyl-12α-ethoxylnimbolinin (1) and 1α-tigloyloxy-3α-acetoxyl-7α-hydroxyl-12β-ethoxylnimbolinin (2), together with other four known limonoids (3-6), were isolated from the fruits of Melia toosendan. Their structures were elucidated by means of extensive spectroscopic analyses (NMR and ESI-MS) and comparisons with the data reported in the literature. The isolated compounds were evaluated for their antibacterial activities. Compound 4 exhibited significant antibacterial activity against an oral pathogen, Porphyromonas gingivalis ATCC 33277, with an MIC value of 15.2 μg·mL(-1). Compound 2 was also active against P. gingivalis ATCC 33277, with an MIC value of 31.25 μg·mL(-1). In conlcusion, our resutls indicate that these compounds may provide a basis for future development of novel antibiotics.
Anti-Bacterial Agents ; chemistry ; isolation & purification ; pharmacology ; Drugs, Chinese Herbal ; chemistry ; isolation & purification ; Fruit ; chemistry ; Limonins ; chemistry ; isolation & purification ; Magnetic Resonance Spectroscopy ; Melia ; chemistry ; Molecular Structure ; Porphyromonas gingivalis ; drug effects ; growth & development ; Spectrometry, Mass, Electrospray Ionization

Sub-gingival anaerobic pathogens can colonize an implant surface to compromise osseointegration of dental implants once the soft tissue seal around the neck of an implant is broken. In vitro evaluations of implant materials are usually done in monoculture studies involving either tissue integration or bacterial colonization. Co-culture models, in which tissue cells and bacteria battle simultaneously for estate on an implant surface, have been demonstrated to provide a better in vitro mimic of the clinical situation. Here we aim to compare the surface coverage by U2OS osteoblasts cells prior to and after challenge by two anaerobic sub-gingival pathogens in a co-culture model on differently modified titanium (Ti), titanium-zirconium (TiZr) alloys and zirconia surfaces. Monoculture studies with either U2OS osteoblasts or bacteria were also carried out and indicated significant differences in biofilm formation between the implant materials, but interactions with U2OS osteoblasts were favourable on all materials. Adhering U2OS osteoblasts cells, however, were significantly more displaced from differently modified Ti surfaces by challenging sub-gingival pathogens than from TiZr alloys and zirconia variants. Combined with previous work employing a co-culture model consisting of human gingival fibroblasts and supra-gingival oral bacteria, results point to a different material selection to stimulate the formation of a soft tissue seal as compared to preservation of osseointegration under the unsterile conditions of the oral cavity.
Acid Etching, Dental ; methods ; Alloys ; chemistry ; Bacterial Adhesion ; physiology ; Bacteriological Techniques ; Biofilms ; Cell Adhesion ; physiology ; Cell Culture Techniques ; Cell Line, Tumor ; Cell Movement ; physiology ; Ceramics ; chemistry ; Coculture Techniques ; Dental Alloys ; chemistry ; Dental Etching ; methods ; Dental Implants ; microbiology ; Dental Materials ; chemistry ; Dental Polishing ; methods ; Humans ; Osseointegration ; physiology ; Osteoblasts ; physiology ; Porphyromonas gingivalis ; physiology ; Prevotella intermedia ; physiology ; Surface Properties ; Titanium ; chemistry ; Yttrium ; chemistry ; Zirconium ; chemistry

Oral mucosal and salivary lipids exhibit potent antimicrobial activity for a variety of Gram-positive and Gram-negative bacteria; however, little is known about their spectrum of antimicrobial activity or mechanisms of action against oral bacteria. In this study, we examine the activity of two fatty acids and three sphingoid bases against Porphyromonas gingivalis, an important colonizer of the oral cavity implicated in periodontitis. Minimal inhibitory concentrations, minimal bactericidal concentrations, and kill kinetics revealed variable, but potent, activity of oral mucosal and salivary lipids against P. gingivalis, indicating that lipid structure may be an important determinant in lipid mechanisms of activity against bacteria, although specific components of bacterial membranes are also likely important. Electron micrographs showed ultrastructural damage induced by sapienic acid and phytosphingosine and confirmed disruption of the bacterial plasma membrane. This information, coupled with the association of treatment lipids with P. gingivalis lipids revealed via thin layer chromatography, suggests that the plasma membrane is a likely target of lipid antibacterial activity. Utilizing a combination of two-dimensional in-gel electrophoresis and Western blot followed by mass spectroscopy and N-terminus degradation sequencing we also show that treatment with sapienic acid induces upregulation of a set of proteins comprising a unique P. gingivalis stress response, including proteins important in fatty acid biosynthesis, metabolism and energy production, protein processing, cell adhesion and virulence. Prophylactic or therapeutic lipid treatments may be beneficial for intervention of infection by supplementing the natural immune function of endogenous lipids on mucosal surfaces.
Anti-Bacterial Agents ; pharmacology ; Bacterial Proteins ; drug effects ; Colony Count, Microbial ; Fatty Acids ; pharmacology ; Humans ; Lipids ; pharmacology ; Microscopy, Electron ; Mouth Mucosa ; chemistry ; immunology ; microbiology ; Porphyromonas gingivalis ; chemistry ; drug effects ; ultrastructure ; Saliva ; chemistry ; microbiology ; Sphingolipids ; pharmacology ; Virulence ; drug effects

Protein phosphorylation on tyrosine has emerged as a key device in the control of numerous cellular functions in bacteria. In this article, we review the structure and function of bacterial tyrosine kinases and phosphatases. Phosphorylation is catalyzed by autophosphorylating adenosine triphosphate-dependent enzymes (bacterial tyrosine (BY) kinases) that are characterized by the presence of Walker motifs. The reverse reaction is catalyzed by three classes of enzymes: the eukaryotic-like phosphatases (PTPs) and dual-specific phosphatases; the low molecular weight protein-tyrosine phosphatases (LMW-PTPs); and the polymerase-histidinol phosphatases (PHP). Many BY kinases and tyrosine phosphatases can utilize host cell proteins as substrates, thereby contributing to bacterial pathogenicity. Bacterial tyrosine phosphorylation/dephosphorylation is also involved in biofilm formation and community development. The Porphyromonas gingivalis tyrosine phosphatase Ltp1 is involved in a restraint pathway that regulates heterotypic community development with Streptococcus gordonii. Ltp1 is upregulated by contact with S. gordonii and Ltp1 activity controls adhesin expression and levels of the interspecies signal AI-2.
Bacteria ; enzymology ; Bacterial Proteins ; genetics ; metabolism ; Biofilms ; growth & development ; Gene Expression Regulation, Bacterial ; Host-Pathogen Interactions ; Phosphorylation ; Polysaccharides, Bacterial ; biosynthesis ; Porphyromonas gingivalis ; enzymology ; Protein Processing, Post-Translational ; Protein Structure, Tertiary ; Protein Tyrosine Phosphatases ; chemistry ; genetics ; metabolism ; Protein-Tyrosine Kinases ; chemistry ; genetics ; metabolism ; Quorum Sensing ; Signal Transduction ; Streptococcus gordonii ; enzymology ; Virulence Factors ; metabolism

OBJECTIVETo investigate whether signaling through Toll-like receptor-2 (TLR-2) can affect the expression of some cytokines in human gingival fibroblasts.

METHODSThe gingival fibroblasts were isolated and cultured in vivo, divided into blank control group, lipopolysaccharide (LPS) from Porphyromonas gingivalis (Pg) group and Escherichia coli (Ec) group. mRNA expression levels were measured by real-time polymerase chain reaction (PCR). The protein expression levels were detected by the enzyme linked immunosorbent assay (ELISA). The data was statistically analyzed by SPSS16.0 software package.

RESULTSLPS from Pg could stimulate the expression of interleukin (IL)-6 and leukemia inhibitory factor (LIF) mRNA and protein, which reached the peak (5.87 ± 0.83) at 10 h, and the expression level increased with the increase of the Pg concentration. IL-11 or oncostatin-M (OSM) mRNA expression was not affected by LPS. After treated with Pg for 48 h, the protein expression of IL-6 and LIF was up-regulated, (962 ± 57) ng/L and (47 ± 18) ng/L respectively.

CONCLUSIONSSignaling through TLR-2 controls the expression of cytokines of IL-6 family in human gingival fibroblasts.

Adolescent ; Adult ; Cells, Cultured ; Child ; Dose-Response Relationship, Drug ; Escherichia coli ; chemistry ; Fibroblasts ; cytology ; metabolism ; Gingiva ; cytology ; Humans ; Interleukin-11 ; genetics ; metabolism ; Interleukin-6 ; genetics ; metabolism ; Leukemia Inhibitory Factor ; genetics ; metabolism ; Lipopeptides ; pharmacology ; Lipopolysaccharides ; administration & dosage ; isolation & purification ; pharmacology ; Oncostatin M ; genetics ; metabolism ; Porphyromonas gingivalis ; chemistry ; RNA, Messenger ; metabolism ; Signal Transduction ; Toll-Like Receptor 2 ; agonists ; Young Adult

OBJECTIVETo determine the effect of Porphyromonas gingivalis lipopolysaccharide (LPS) on induced secretion of inflammatory cytokines by different cell lines.

METHODSLPS of P. gingivalis strain ATCC33277 (Pg-LPS) was extracted with phenol-water method, and identified by Limulus test and infrared spectrum analysis. KB, HGF-1 and THP-1 cells were treated with Pg-LPS of different concentrations and time duration, a commercial LPS of E.coli strain O111:B4 (E-LPS) was used as the control. TNF-alpha, IL-1beta, IL-6 and IL-8 levels in culture supernatants were measured by quantitative ELISA.

RESULTThe minimal dosages of both Pg-LPS and E-LPS to solidify Limulus agents were 15 ng/ml and their infrared spectrums were similar. With the treatment of Pg-LPS or E-LPS, the TNF-alpha and IL-1beta levels secreted by HGF-1 cells were remarkably increased with a single perk (P<0.01) while a continuous enhancement of secretion by THP-1 cells was observed (P<0.01). Either Pg-LPS or E-LPS stimulated HGF-1 or THP-1 cells to continuously increase the secretion of IL-6 (P<0.01). Both Pg-LPS and E-LPS induced IL-8 secretion by THP-1 cells (P<0.01), but only Pg-LPS showed the similar effect on HGF-1 cells (P<0.01). Neither Pg-LPS nor E-LPS induced KB cells to secrete inflammatory cytokines.

CONCLUSIONPg-LPS can promote target cells to increase their secretion of inflammatory cytokines. KB cells can not be used as the target cell to determine inflammation-causing effect of LPS.

Cell Line ; Epithelial Cells ; cytology ; metabolism ; Fibroblasts ; cytology ; metabolism ; Humans ; Interleukin-1beta ; secretion ; Interleukin-6 ; secretion ; Interleukin-8 ; secretion ; Lipopolysaccharides ; pharmacology ; Porphyromonas gingivalis ; chemistry ; Tumor Necrosis Factor-alpha ; secretion

OBJECTIVETo study antibacterial chemical constituents of Sarcandra glabra.

METHODThe constituents of the chloroform and EtOAc-soluble portions of the EtOH extract from the whole plant of S. glabra, which posses the antibacterial activities, were isolated and purified with column chromatography. The compounds were identified by physical and spectroscopic techniques.

RESULTSix compounds were isolated and identified as 4, 4'-biisofraxidin (1), esculetin (2), fraxetin (3), scoparone (4), isofraxidin (5), scopoletin(6), respectively.

CONCLUSIONCompound 1 is a novel natural product. Compounds 24 were isolated from the plants of Chloranthaceae for the first time. The antibacterial activities of these six compounds were tested for the first time. Some compounds may have potential for future study and development as plant-derived oral antibacterial agents.

Anti-Bacterial Agents ; analysis ; chemistry ; isolation & purification ; pharmacology ; Coumarins ; analysis ; isolation & purification ; pharmacology ; Drugs, Chinese Herbal ; chemistry ; Magnetic Resonance Spectroscopy ; Magnoliopsida ; chemistry ; Porphyromonas gingivalis ; drug effects ; Spectrometry, Mass, Electrospray Ionization ; Spectrophotometry, Infrared ; Streptococcus mutans ; drug effects