Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0031099 (periodontitis)
 12,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Porphyromonas gingivalis has been implicated as an etiologic agent of adult periodontitis. We have previously shown that P. gingivalis can degrade the epithelial cell-cell junction complexes, thus suggesting that this bacterium can invade the underlying connective tissues via a paracellular pathway. However, the precise mechanism(s) involved in this process has not been elucidated. The purpose of this study was to determine if the arginine- and lysine-specific gingipains of P. gingivalis (i.e., HRgpA and RgpB, and Kgp, respectively) were responsible for the degradation of E-cadherin, the cell-cell adhesion protein in the adherens junctions. In addition, we compared the degradative abilities of the whole gingipains HRgpA and Kgp to those of their catalytic domains alone. In these studies, immunoprecipitated E-cadherin as well as monolayers of polarized Madin-Darby canine kidney (MDCK) epithelial cell cultures were incubated with the gingipains and hydrolysis of E-cadherin was assessed by Western blot analysis. Incubation of P. gingivalis cells with immunoprecipitated E-cadherin resulted in degradation, whereas prior exposure of P. gingivalis cells to leupeptin and especially acetyl-Leu-Val-Lys-aldehyde (which are arginine- and lysine-specific inhibitors, respectively) reduced this activity. Furthermore, incubation of E-cadherin immunoprecipitates with the different gingipains resulted in an effective and similar hydrolysis of the protein. However, when monolayers of MDCK cells were exposed to the gingipains, Kgp was most effective in hydrolyzing the E-cadherin molecules in the adherens junction. Kgp was more effective than its catalytic domain in degrading E-cadherin at 500 nM but not at a lower concentration (250 nM). These results suggest that the hemagglutinin domain of Kgp plays a role in degradation and that there is a critical threshold concentration for this activity. Taken together, these results provide evidence that the gingipains, especially Kgp, are involved in the degradation of the adherens junction of epithelial cells, which may be important in the invasion of periodontal connective tissue by P. gingivalis.
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PMID:Hydrolysis of epithelial junctional proteins by Porphyromonas gingivalis gingipains. 1195 90

The article reveals patterns of changes in the parameters of oxidative modification of proteins for different periods of the inflammatory process in periodontal tissues during periodontitis. Biochemical researches of phenylhydrazones, aldehyde-, and ketone derivatives of neutral and basic proteins were determined in the blood of white rats on the 7th, 14th, and 30th days of the experimental periodontitis development, as well as in intact animals. The method for determination of the oxidative modification of proteins was based on the interaction of oxidized amino acid residues with 2,4-dinitrophenylhydrazine to form 2,4-dinitrophenylhydrazones. At the early stage of experimental periodontitis development, i.e., on the 7th day, an increase in the products of oxidative modification of proteins of basic and neutral nature was observed in the blood serum, but later, on the 14th day, this index changed in opposite direction, i.e., it began to decrease; however, it was higher relative to the intact group of animals. The obtained factual data evidence that under the conditions of experimental periodontitis formation, there is an intensive increase in the level of oxidative modification of proteins especially in the early period of the inflammatory process development.
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PMID:Oxidative modification of proteins in the process of experimental periodontitis development. 2995 Dec 90