scholarly journals Role of an Arginine Residue Present in Histatin 8 Which Inhibits Coaggregation between Porphyromonas gingivalis and Streptococcus mitis.

1993 ◽  
Vol 43 (2) ◽  
pp. 221-223 ◽  
Author(s):  
Yukitaka MURAKAMI ◽  
Hideki NAGATA ◽  
Satoshi SHIZUKUISHI ◽  
Akira TSUNEMITSU
Keyword(s):  
Porphyromonas Gingivalis ◽  
Arginine Residue ◽  
Streptococcus Mitis ◽  
Histatin 8

scholarly journals The Role of Arg13 in Protein Phosphatase M tPphA from Thermosynechococcus elongatus

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Jiyong Su ◽  
Karl Forchhammer
Keyword(s):  
Amino Acid ◽  
Protein Phosphatase ◽  
Arginine Residue ◽  
Side Chain ◽  
Wild Type ◽  
Catalytic Center ◽  
Nitrophenyl Phosphate ◽  
Reduced Activity ◽  
Amino Acid Variants

A highly conserved arginine residue is close to the catalytic center of PPM/PP2C-type protein phosphatases. Different crystal structures of PPM/PP2C homologues revealed that the guanidinium side chain of this arginine residue can adopt variable conformations and may bind ligands, suggesting an important role of this residue during catalysis. In this paper, we randomly mutated Arginine 13 of tPphA, a PPM/PP2C-type phosphatase from Thermosynechococcus elongatus, and obtained 18 different amino acid variants. The generated variants were tested towards p-nitrophenyl phosphate and various phosphopeptides. Towards p-nitrophenyl phosphate as substrate, twelve variants showed 3–7 times higher Km values than wild-type tPphA and four variants (R13D, R13F, R13L, and R13W) completely lost activity. Strikingly, these variants were still able to dephosphorylate phosphopeptides, although with strongly reduced activity. The specific inability of some Arg-13 variants to hydrolyze p-nitrophenyl phosphate highlights the importance of additional substrate interactions apart from the substrate phosphate for catalysis. The properties of the R13 variants indicate that this residue assists in substrate binding.

scholarly journals Porphyromonas gingivalis lipopolysaccharide stimulation in human periodontal ligament stem cells: role of epigenetic modifications to the inflammation

2017 ◽  
Vol 61 (3) ◽  
Author(s):  
Francesca Diomede ◽  
Soundara Rajan Thangavelu ◽  
Ilaria Merciaro ◽  
Monica D'Orazio ◽  
Placido Bramanti ◽  
...  
Keyword(s):  
Stem Cells ◽  
Porphyromonas Gingivalis ◽  
Inflammatory Disease ◽  
Periodontal Ligament ◽  
Model System ◽  
Epigenetic Mechanism ◽  
Periodontal Ligament Stem Cells ◽  
Porphyromonas Gingivalis Lipopolysaccharide

<p>Periodontitis is a chronic oral inflammatory disease produced by bacteria. Gingival retraction and bone and connective tissues resorption are the hallmarks of this disease. Chronic periodontitis may contribute to the risk of onset or progression of neuroinflammatory pathological conditions, such as Alzheimer’s disease. The main goal of the present study was to investigate if the role of epigenetic modulations is involved in periodontitis using human periodontal ligament stem cells (hPDLSCs) as an <em>in vitro</em> model system. hPDLSCs were treated with lipopolysaccharide of <em>Porphyromonas gingivalis</em> and the expression of proteins associated with DNA methylation and histone acetylation, such as DNMT1 and p300, respectively, and inflammatory transcription factor NF-kB, were examined. Immunofluorescence, Western blot and next generation sequencing results demonstrated that <em>P. gingivalis </em>lipopolysaccharide significantly reduced DNA methylase DNMT1, while it markedly upregulated the level of histone acetyltransferase p300 and NF-kB in hPDLSCs. Our results showed that <em>P. gingivalis </em>lipopolysaccharide markedly regulate the genes involved in epigenetic mechanism, which may result in inflammation induction. We propose that <em>P. gingivalis </em>lipopolysaccharide-treated hPDLSCs could be a potential in vitro model system to study epigenetics modulations associated with periodontitis, which might be helpful to identify novel biomarkers linked to this oral inflammatory disease.</p>

scholarly journals Porphyromonas gingivalis Impairs Oral Epithelial Barrier through Targeting GRHL2

2019 ◽  
Vol 98 (10) ◽  
pp. 1150-1158 ◽  
Author(s):  
W. Chen ◽  
A. Alshaikh ◽  
S. Kim ◽  
J. Kim ◽  
C. Chun ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Oral Mucosa ◽  
Porphyromonas Gingivalis ◽  
Oral Bacteria ◽  
Conditional Knockout ◽  
Epithelial Barrier ◽  
Wild Type ◽  
Oral Epithelial ◽  
Junction Proteins

Oral mucosa provides the first line of defense against a diverse array of environmental and microbial irritants by forming the barrier of epithelial cells interconnected by multiprotein tight junctions (TJ), adherens junctions, desmosomes, and gap junction complexes. Grainyhead-like 2 (GRHL2), an epithelial-specific transcription factor, may play a role in the formation of the mucosal epithelial barrier, as it regulates the expression of the junction proteins. The current study investigated the role of GRHL2 in the Porphyromonas gingivalis ( Pg)–induced impairment of epithelial barrier functions. Exposure of human oral keratinocytes (HOK-16B and OKF6 cells) to Pg or Pg-derived lipopolysaccharides ( Pg LPSs) led to rapid loss of endogenous GRHL2 and the junction proteins (e.g., zonula occludens, E-cadherin, claudins, and occludin). GRHL2 directly regulated the expression levels of the junction proteins and the epithelial permeability for small molecules (e.g., dextrans and Pg bacteria). To explore the functional role of GRHL2 in oral mucosal barrier, we used a Grhl2 conditional knockout (KO) mouse model, which allows for epithelial tissue-specific Grhl2 KO in an inducible manner. Grhl2 KO impaired the expression of the junction proteins at the junctional epithelium and increased the alveolar bone loss in the ligature-induced periodontitis model. Fluorescence in situ hybridization revealed increased epithelial penetration of oral bacteria in Grhl2 KO mice compared with the wild-type mice. Also, blood loadings of oral bacteria (e.g., Bacteroides, Bacillus, Firmicutes, β- proteobacteria, and Spirochetes) were significantly elevated in Grhl2 KO mice compared to the wild-type littermates. These data indicate that Pg bacteria may enhance paracellular penetration through oral mucosa in part by targeting the expression of GRHL2 in the oral epithelial cells, which then impairs the epithelial barrier by inhibition of junction protein expression, resulting in increased alveolar tissue destruction and systemic bacteremia.

scholarly journals Retraction Note: Temporal activation of anti- and pro-apoptotic factors in human gingival fibroblasts infected with the periodontal pathogen, Porphyromonas gingivalis: potential role of bacterial proteases in host signalling

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Sonya Urnowey ◽  
Toshihiro Ansai ◽  
Vira Bitko ◽  
Koji Nakayama ◽  
Tadamichi Takehara ◽  
...  
Keyword(s):  
Porphyromonas Gingivalis ◽  
Potential Role ◽  
Human Gingival Fibroblasts ◽  
Periodontal Pathogen ◽  
Gingival Fibroblasts ◽  
The University ◽  
Apoptotic Factors

The Editor has retracted this article [1] following an investigation by the University of South Alabama which found:

scholarly journals Potential Role of Phosphoglycerol Dihydroceramide Produced by Periodontal Pathogen Porphyromonas gingivalis in the Pathogenesis of Alzheimer’s Disease

2020 ◽  
Vol 11 ◽  
Author(s):  
Chiaki Yamada ◽  
Juliet Akkaoui ◽  
Anny Ho ◽  
Carolina Duarte ◽  
Richard Deth ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Porphyromonas Gingivalis ◽  
Virulence Factors ◽  
Potential Role ◽  
Sirtuin 1 ◽  
Periodontal Pathogen ◽  
Secretory Phenotype ◽  
Aβ42 Peptide

BackgroundAmong different types of sphingolipids produced by human cells, the possible engagement of ceramide species in the pathogenesis of Alzheimer’s disease (AD) has attracted recent attention. While ceramides are primarily generated by de novo synthesis in mammalian cells, only a limited number of bacterial species, produce ceramides, including phosphoglycerol dihydroceramide (PGDHC) that is produced by the key periodontal pathogen Porphyromonas gingivalis. Emerging evidence indicates that virulence factors produced by P. gingivalis, such as lipopolysaccharide and gingipain, may be engaged in the initiation and/or progression of AD. However, the potential role of PGDHC in the pathogenesis of AD remains unknown. Therefore, the aim of this study was to evaluate the influence of PGDHC on hallmark findings in AD.Material and MethodsCHO-7WD10 and SH-SY-5Y cells were exposed to PGDHC and lipopolysaccharide (LPS) isolated from P. gingivalis. Soluble Aβ42 peptide, amyloid precursor protein (APP), phosphorylated tau and senescence-associated secretory phenotype (SASP) factors were quantified using ELISA and Western blot assays. ResultsOur results indicate that P. gingivalis (Pg)-derived PGDHC, but not Pg-LPS, upregulated secretion of soluble Aβ42 peptide and expression of APP in CHO-7WD10 cells. Furthermore, hyperphosphorylation of tau protein was observed in SH-SY-5Y cells in response to PGDHC lipid. In contrast, Pg-LPS had little, or no significant effect on the tau phosphorylation induced in SH-SY-5Y cells. However, both PGDHC and Pg-LPS contributed to the senescence of SH-SY5Y cells as indicated by the production of senescence-associated secretory phenotype (SASP) markers, including beta-galactosidase, cathepsin B (CtsB), and pro-inflammatory cytokines TNF-α, and IL-6. Additionally, PGDHC diminished expression of the senescence-protection marker sirtuin-1 in SH-SY-5Y cells.ConclusionsAltogether, our results indicate that P. gingivalis-derived PGDHC ceramide promotes amyloidogenesis and hyperphosphorylation, as well as the production of SASP factors. Thus, PGDHC may represent a novel class of bacterial-derived virulence factors for AD associated with periodontitis.

In Vitro Invasion and Survival of Porphyromonas gingivalis in Gingival Fibroblasts; Role of the Capsule

2012 ◽  
Vol 60 (6) ◽  
pp. 469-476 ◽  
Author(s):  
Muhammad Irshad ◽  
Wil A. van der Reijden ◽  
Wim Crielaard ◽  
Marja L. Laine
Keyword(s):  
Porphyromonas Gingivalis ◽  
Gingival Fibroblasts ◽  
In Vitro Invasion

scholarly journals VimA is part of the maturation pathway for the major gingipains of Porphyromonas gingivalis W83

Microbiology ◽  
2006 ◽  
Vol 152 (11) ◽  
pp. 3383-3389 ◽  
Author(s):  
E. Vanterpool ◽  
F. Roy ◽  
W. Zhan ◽  
S. M. Sheets ◽  
L. Sangberg ◽  
...  
Keyword(s):  
Gene Product ◽  
Porphyromonas Gingivalis ◽  
Protein Interaction ◽  
Protein Protein Interaction ◽  
Interaction Studies ◽  
Defective Mutant ◽  
Protease Activation ◽  
Porphyromonas Gingivalis W83

The authors have shown previously that the vimA gene, which is part of the bcp-recA-vimA operon, plays an important role in protease activation in Porphyromonas gingivalis. The gingipain RgpB proenzyme is secreted in the vimA-defective mutant P. gingivalis FLL92. An important question that is raised is whether the vimA gene product could directly interact with the proteases for their activation or regulate a pathway responsible for protease activation. To further study the mechanism(s) of VimA-dependent protease activation, the vimA gene product was further characterized. A 39 kDa protein consistent with the size of the predicted VimA protein was purified. In protein–protein interaction studies, the VimA protein was shown to interact with gingipains RgpA, RgpB and Kgp. Immune sera from mice immunized with P. gingivalis immunoreacted with the purified VimA protein. Taken together, these data suggest an interaction of VimA with the gingipains and further confirm the role of this protein in their regulation or maturation.

scholarly journals Arthritic role of Porphyromonas gingivalis in collagen-induced arthritis mice

PLoS ONE ◽  
2017 ◽  
Vol 12 (11) ◽  
pp. e0188698 ◽  
Author(s):  
Hyerin Jung ◽  
Seung Min Jung ◽  
Yeri Alice Rim ◽  
Narae Park ◽  
Yoojun Nam ◽  
...  
Keyword(s):  
Porphyromonas Gingivalis ◽  
Collagen Induced Arthritis
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