Stimulation of plasmin activity in cultured human fibroblast cells by Porphyromonas endodontalis

The plasminogen activation system in periodontal tissue (Review)

The plasminogen activation system (PAS) plays an essential role in tissue proteolysis in physiological and pathological processes. Periodontitis is a chronic infection associated with increased proteolysis driven by plasminogen activation. In this comprehensive review, we summarise the effects of PAS in wound healing, tissue remodelling, inflammation, bacterial infection, and in the initiation and progression of periodontal disease. Specifically, we discuss the role of plasminogen activators (PAs), including urokinase PA (uPA), tissue-type PA (tPA), PA inhibitor type 1 (PAI-1) and 2 (PAI-2) and activated plasminogen in periodontal tissue, where their concentrations can reach much higher values than those found in other parts of the body. We also discuss whether PA deficiencies can have effects on periodontal tissue. We conclude that in periodontal disease, PAS is unbalanced and equalizing its function can improve the clinical periodontal tissue condition.

Effect of Escherichia coli lipopolysaccharide on u-PA activity and u-PA and u-PAR RNA expression in a bovine mammary epithelial cell line

It is well known that the plasminogen-activating (PA) system plays a key role in the bovine mammary gland during tissue remodelling. However, the modulation of the PA cascade after bacterial infections needs to be elucidated. This study examined the effects of Escherichia coli lipopolysaccharide (LPS) on cell viability, the modulation of cell-associated u-PA activity, and the regulation of u-PA and u-PA receptor (u-PAR) RNA expression using the BME-UV1 bovine mammary epithelial cell line. LPS did not affect cell viability, but induced an increase in u-PA activity, with the maximum response after 6 h of incubation. Moreover, u-PA and u-PAR mRNA expression were both up-regulated in BME-UV1 cells after 3 h of incubation with LPS. These data indicated that E. coli LPS led to an increase in u-PA activity and RNA expression of u-PA and u-PAR in BME-UV1 cells, thus strengthening the role of the PA system during pathological processes.

The purification and characterization of an 88-kDa Porphyromonas endodontalis 35406 protease

A Porphyromonas endodontalis ATCC 35406 protease was purified from Triton X-114 cell extracts by preparative SDS-PAGE followed by electroelution. The purified enzyme exhibits a molecular size of 88 kDa and was dissociated into two polypeptides of 43 and 41 kDa upon heating in the presence of sodium dodecyl sulfate with or without a reducing agent. The protease (pH optimum 7.5-8.0) degraded the extracellular matrix proteins fibrinogen and fibronectin. Collagen IV was also degraded at 37 degrees C but not at 28 degrees C. The protease also cleaved the bioactive peptide angiotensin at amino acid residue phenylalanine-8 and tyrosine-4 but failed to hydrolyze bradykinin, vasopressin and synthetic chromogenic substrates with phenylalanine or tyrosine at the P1 position. In addition, two peptidases were detected in P. endodontalis cells: a proline aminopeptidase that remained associated with the cell pellet after detergent extraction and peptidase/s that partitioned into the Triton X-114 phase after phase separation and degraded the bioactive peptides bradykinin and vasopressin. These P. endodontalis peptidases and proteases may play an important role in both the nutrition and pathogenicity of these assacharolytic microorganisms. The inactivation of bioactive peptides and degradation of extracellular matrix proteins by bacterial enzymes may contribute to the damage of host tissues accompanied with endodontic infections.

Whole genomic DNA probe for detection of Porphyromonas endodontalis

The purpose of the present study was to develop a DNA probe for Porphyromonas endodontalis. Pure cultures of P. endodontalis were grown in TYP medium, in an anaerobic chamber. DNA was extracted from the P. endodontalis and labeled using the Genius System by Boehringer Mannheim. The labeled P. endodontalis DNA was used in dot-blot hybridization reactions with homologous (P. endodontalis) and unrelated bacterial samples. To determine specificity, strains of 40 other oral bacterial species (e.g. Porphyromonas gingivalis, Porphyromonas asaccharolytica, and Prevotella intermedia) were spotted and reacted with the P. endodontalis DNA probe. None of the panel of 40 oral bacteria hybridized with the P. endodontalis probe, whereas the blot of the homologous organism showed a strong positive reaction. To determine the sensitivity of the probe, dilutions of a P. endodontalis suspension of known concentration were blotted onto a nylon membrane and reacted with the probe. The results of our investigation indicate that the DNA probe that we have prepared specifically detects only P. endodontalis and can detect at least 3 x 10(4) cells.

Cell cycle-dependent fluctuation of urokinase-type plasminogen activator, its receptor, and inhibitors in cultured bovine mammary epithelial and myoepithelial cells

Bovine mammary epithelial (BME-UV1, clone E-T and BME-UV, clone E-T2) and myoepithelial (BMM-UV, clone m-T2) cell lines were used to study the modulation of cell-associated activity of urokinase-type plasminogen activator (u-PA), as well as mRNA transcripts of u-PA, its receptor (u-PAR), and inhibitors (PAI-1 and PAI-2) during the cell cycle. After release from a growth arrest accomplished by growth factor deprivation, the length of the cell cycle was determined as 19-21 h, with G1, S, and G2+M phases of 6-7, 7-9, and 5-6 h respectively. As the cell cycle progressed, accumulated cell-associated u-PA activity increased. Maximal activity occurred at the S/G2 boundary and decreased during the G2/M phases. All cell lines tested produced plasmin-specific inhibitor(s). Accumulation of u-PA mRNA peaked 3 h after stimulation into the growth cycle for m-T2 and E-T and during 3-6 h for E-T2 cells. Maximum levels of u-PAR mRNA were observed at 3 h for the E-T cell line, 6-9 h for E-T2 cells, and 3-9 h for m-T2 cells. The cell cycle distribution of the PAI-1 mRNA was similar to that of u-PA for both epithelial cell lines, while for m-T2 cells maximal accumulation of PAI-1 mRNA was detected at 3-9 h after growth initiation. The increase of PAI-2 mRNA transcription for m-T2 and E-T cells was detected at 3-6 h. The PAI-2 mRNA in E-T2 cells was under detectable levels. The data indicate that the expression of the constituents of the PA system in bovine mammary epithelial and myoepithelial cells is not cell type-dependent but is tightly connected to the phase of the cell cycle.

Immunohistochemical demonstration of the plasminogen activator system in human gingival tissues and gingival fibroblasts

The relative distribution of urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1) and plasminogen activator inhibitor-2 (PAI-2) was studied in cultured human gingival fibroblasts, healthy gingival tissues and inflamed gingival tissues by immunohistochemistry. In cultured gingival fibroblasts t-PA, u-PA and PAI-1 were expressed in cytoplasm; u-PA and PAI-1 were more intensely stained than t-PA; PAI-2 was not detectable in gingival fibroblasts. Following interleukin 1 beta (IL-1 beta) stimulation, the intensity of intracellular staining for t-PA was increased and a number of cells staining strongly for PAI-2 were seen; no difference in the intensity of immunostaining level was noted for the expression of u-PA and PAI-1 between IL-1 beta stimulated cells and unstimulated cells. In healthy gingival tissues, u-PA and PAI-1 displayed a wide distribution throughout all the connective tissue and epithelium; t-PA localized mainly in the connective tissue while PAI-2 showed little association with the connective tissue but did faintly stain in the epithelial layer. In inflamed gingival tissues, staining for t-PA was significantly increased in the extracellular matrix of the connective tissue, whereas staining for u-PA, PAI-1 and PAI-2 was found to be slightly increased, but no significant difference was noted for staining when compared with the healthy gingival tissues. A granular distribution of t-PA, u-PA, PAI-1 and PAI-2 was noted around areas of inflammatory cell infiltration. These immunohistochemical findings indicate that the plasminogen activator system produced by fibroblasts may be influenced by the presence of the inflammatory mediator IL-1 beta. In addition, the significant increase of t-PA in inflamed connective tissue and the wide expression of these components around inflamed cells may contribute to connective tissue degradation and may relate to the migration and localization of monocytes/macrophages in inflamed tissue.