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T Sorsa

Publications and source records attributed to T Sorsa.

At least 109 records · Page 6Linked to original sources
PubMed1999

Analysis of 16 different matrix metalloproteinases (MMP-1 to MMP-20) in the synovial membrane: different profiles in trauma and rheumatoid arthritis.

OBJECTIVE: To define the pattern of mRNA expression of all human matrix metalloproteinases (MMPs) described to date in rheumatoid arthritis (RA) and traumatic synovial membrane, in order to differentiate between a physiological tissue remodelling pattern and that associated with inflammatory tissue destruction. METHODS: Analysis of SwissProt protein and EMBL/GenBank nucleotide sequence banks, protein sequence alignment, reverse transcriptase-polymerase chain reaction and nucleotide sequencing were used. RESULTS: MMP-2 (gelatinase A), MMP-3 (stromelysin-1), MMP-11 (stromelysin-3) and MMP-19 were constitutively expressed. MMP-1 (fibroblast type collagenase), MMP-9 (gelatinase B) and MMP-14 (MT1-MMP) were expressed in all RA, but only in 55-80% of trauma samples. MMP-13 (collagenase-3) and MMP-15 (MT2-MMP) were expressed exclusively in RA (80-90% of the samples). MMP-20 (enamelysin) was absent and MMP-8 (collagenase-2) was rarely found in RA or trauma. All other MMPs (-7, -10, -12, -16, -17) had an intermediate pattern of expression. CONCLUSIONS: Some MMPs without interstitial collagenase activity seem to have a constitutive pattern of expression and probably participate in physiological synovial tissue remodelling. Some MMPs are exclusively associated to RA synovitis, for example, MMP-13, which preferentially degrades type II collagen and aggrecan, and MMP-15, which activates proMMP-2 and proMMP-13 and is involved in tumour necrosis factor alpha processing. This clear cut rheumatoid/inflammatory MMP profile, more complex than has been previously appreciated, may facilitate inflammatory tissue destruction in RA.

Adult↗
PubMed1999

Transforming and epidermal growth factors in degenerated intervertebral discs.

We studied the presence of anabolic growth factors in human herniated intervertebral discs (IVD) using a reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry. Messenger RNA (mRNA) was isolated from the nucleus pulposus using oligo (dT)25 superparamagnetic beads and probing with gene-specific primers in RT-PCR. mRNA coding for TGF-alpha (3/10), EGF (0/10), TGF-beta1 (0/10) and TGF-beta3 (2/10) or the EGF receptor (EGF-R; 0/10) and TGF-beta type-II receptor (0/10) was found only occasionally. Beta-actin was always present and positive sample controls confirmed the validity of the RT-PCR assay. These RT-PCR findings were confirmed using immunohistochemical staining of EGF and TFG-beta, whereas TGF-alpha protein was always found associated with discocytes. We conclude that the nucleus pulposus of the herniated IVD is vulnerable to proteolytic degradation and depletion of proteoglycans due to the lack and/or low production of anabolic growth factors/receptors which could increase the local synthesis of the extracellular matrix.

Actins↗
PubMed1999

The association between smoking cessation and periodontal status and salivary proteinase levels.

BACKGROUND: Little information is available about the effects of the cessation of cigarette smoking on oral health, although cigarette smoking has been shown to be associated with a variety of oral diseases. The aim of this study was to compare periodontal status, salivary proteolytic activity, especially collagenase-2 (MMP-8) levels, and oral mucosal status in individuals who had quit smoking for at least 6 months (mean 3.5, SD 1.3 years) and in regular smokers. METHODS: The subjects were 409 white male smokers aged 55 to 74 years with 15 or more remaining teeth. They had participated in a major cancer prevention study (ATBC Study). Eighty-two of the men had given up smoking and 327 were smokers. The subjects were examined clinically to determine the prevalence of periodontal pockets, gingival bleeding (BOP) and suppuration, and prevalence of keratotic oral mucosal lesions. The loss of alveolar bone was determined radiographically. Candida albicans was cultivated, and lesions showing leukoplakia were examined histopathologically. General proteolytic activity and collagenase-2 or matrix metalloproteinase-8 (MMP-8) levels in saliva, salivary pH, and buffering capacity were measured. Linear regression, logistic regression, or Fisher's exact test were used in statistical analysis. RESULTS: Salivary general proteolytic activity and MMP-8 levels were lower in current smokers than in ex-smokers (P <0.05 and P <0.05, respectively). The prevalence of > or = 4 mm deep pockets, gingival suppuration, and loss of crestal bone were statistically significantly lower (P = 0.003, P<0.001, and P<0.05, respectively) and salivary buffering capacity higher (P <0.05) in those who had quit smoking compared to current smokers; there was no difference in BOP. The prevalence of oral leukoplakia did not differ significantly between smokers and quitters, but was higher in those who smoked >15 cigarettes per day compared to quitters (odds ratio 3.5, 95% CI, 0.8 to 15.3). CONCLUSIONS: These data suggest that periodontal status and oral mucosal health are better in those who have quit cigarette smoking compared to current smokers. However, the data further suggest that smoking may significantly lower both general proteolytic enzyme activity and MMP-8 levels in saliva. Thus, care should be taken in interpreting results revealing salivary/mouthrinse proteinases as diagnostic markers for oral/periodontal disease activity.

Aged↗
PubMed1998

Solution structure and main chain dynamics of the regulatory domain (Residues 1-91) of human cardiac troponin C.

The three-dimensional structure of calcium-loaded regulatory, i.e. N-terminal, domain (1-91) of human cardiac troponin C (cNTnC) was determined by NMR in water/trifluoroethanol (91:9 v/v) solution. The single-calcium-loaded cardiac regulatory domain is in a "closed" conformation with comparatively little exposed hydrophobic surface. Difference distance matrices computed from the families of Ca2+-cNTnC, the apo and two-calcium forms of the skeletal TnC (sNTnC) structures reveal similar relative orientations for the N, A, and D helices. The B and C helices are closer to the NAD framework in Ca2+-cNTnC and in apo-sNTnC than in 2.Ca2+-sNTnC. However, there is an indication of a conformational exchange based on broad 15N resonances for several amino acids measured at several temperatures. A majority of the amides in the alpha-helices and in the calcium binding loop exhibit very fast motions with comparatively small amplitudes according to the Lipari-Szabo model. A few residues at the N and C termini are flexible. Data were recorded from nonlabeled and 15N-labeled samples, and backbone dynamics was investigated by 15N T1, T2, and heteronuclear nuclear Overhauser effect as well as by relaxation interference measurements.

Amino Acid Sequence↗
PubMed1998

A recombinant mutant vascular endothelial growth factor-C that has lost vascular endothelial growth factor receptor-2 binding, activation, and vascular permeability activities.

The vascular endothelial growth factor (VEGF) and the VEGF-C promote growth of blood vessels and lymphatic vessels, respectively. VEGF activates the endothelial VEGF receptors (VEGFR) 1 and 2, and VEGF-C activates VEGFR-3 and VEGFR-2. Both VEGF and VEGF-C are also potent vascular permeability factors. Here we have analyzed the receptor binding and activating properties of several cysteine mutants of VEGF-C including those (Cys156 and Cys165), which in other platelet-derived growth factor/VEGF family members mediate interchain disulfide bonding. Surprisingly, we found that the recombinant mature VEGF-C in which Cys156 was replaced by a Ser residue is a selective agonist of VEGFR-3. This mutant, designated DeltaNDeltaC156S, binds and activates VEGFR-3 but neither binds VEGFR-2 nor activates its autophosphorylation or downstream signaling to the ERK/MAPK pathway. Unlike VEGF-C, DeltaNDeltaC156S neither induces vascular permeability in vivo nor stimulates migration of bovine capillary endothelial cells in culture. These data point out the critical role of VEGFR-2-mediated signal transduction for the vascular permeability activity of VEGF-C and strongly suggest that the redundant biological effects of VEGF and VEGF-C depend on binding and activation of VEGFR-2. The DeltaNDeltaC156S mutant may provide a valuable tool for the analysis of VEGF-C effects mediated selectively via VEGFR-3. The ability of DeltaNDeltaC156S to form homodimers also emphasizes differences in the structural requirements for VEGF and VEGF-C dimerization.

Animals↗
PubMed1998

Anti-collagenolytic mechanism of action of doxycycline treatment in rheumatoid arthritis.

Tetracyclines exert, independently of their antimicrobial activity, anti-collagenolytic effects by inhibiting activities of human interstitial collagenases and by preventing the oxidative activation of latent pro-collagenases. We tested the clinical response to a 3-month doxycycline in concert with collagenase activity in 12 rheumatoid arthritis (RA) patients. Patients received 150 mg/day of doxycycline for 3 months. Clinical assessments at zero, six and 12 weeks comprised classification of the functional class, joint score index, Hb, CRP, ESR, health assessment questionnaire, visual analogue scale (VAS) of pain, pain disability index, comprehensible psychopathological rating scale (CPRS), SDS-PAGE laser densitometric collagenase activity measurements and Western blots. Significant reductions were seen in joint score index (P < 0.01), pain VAS (P < 0.05) and some CPRS parameters. Furthermore, collagenase activities measured from saliva by quantitative SDS-PAGE electrophoresis were significantly reduced during the 12-week intervention (P < 0.01). Western blots demonstrated intact 75-80 kDa enzyme protein (classic neutrophil collagenase), but also a newly discovered mesenchymal, less glycosylated 40-55 kDa MMP-8 subtype of fibroblast/chondrocytic origin. These results indicate that the documented favourable clinical response may in part be due to in vivo inhibition of classic neutrophil and mesenchymal collagenase/MMP-8 activities produced by doxycycline. This anti-collagenolytic doxycycline effects is mediated through inhibition of the enzyme activity and not through degradation of the enzyme, which may have contributed to the reportedly reduced tissue destruction, as has been seen in clinical studies concerning RA as well as reactive arthritis.

Anti-Bacterial Agents↗
PubMed1998

Production of platelet-derived growth factor in aseptic loosening of total hip replacement.

Aseptic loosening is the predominant cause of total hip implant failure. It has been assumed that a layer or membrane, containing macrophages, fibroblasts and vascular endothelial cells, of synovial-like tissue develops at the implant-to-bone interface almost invariably and, with time, somehow leads to loosening of the components from the surrounding bone. These cells produce a variety of cytokines and proteolytic enzymes which stimulate bone resorption. Platelet derived growth factor (PDGF) may be one of the cytokines which stimulate bone resorption and contribute to aseptic loosening in total hip replacement (THR). Synovial-like membrane from the implant or cement-to-bone interface (n = 10) and pseudocapsule (n = 10) were obtained from ten patients operated on for aseptic loosening of THR. As a control, nine samples of connective tissues were obtained from patients who had mandibular or maxillary fractures fixed with bone implant. The avidin-biotin-peroxidase complex (ABC) method with polyclonal rabbit anti-human IgG against the A-chain and B-chain of PDGF was used for staining. ABC-alkaline phosphatase-anti-alkaline-phosphatase double staining with monoclonal mouse anti-human fibroblast IgG1 and CD68 antibodies was used to ascertain the cellular origin of PDGF. Results of the PDGF staining were quantitated by a semi-automatic VIDAS image analysis system. The PDGF-A and PDGF-B chain containing cells were found in all periprosthetic tissues, in particular in macrophages with phagocytosed particulate debris, but to some extent also in fibroblasts and in endothelial cells. The numbers of PDGF-A and PDGF-B chain positive cells per mm 2 in synovial-like interface membrane (1881 +/- 486 and 1877 +/- 214) and pseudocapsule (1786 +/- 236 and 1676 +/- 152) were higher (P < 0.01) around loose THR than in control tissue (821 +/- 112 and 467 +/- 150), respectively. The results of the present study suggest that PDGF is preferably expressed by macrophages, which to an increased extent produce it in the synovial-like interface membrane and pseudocapsular synovial-like membrane. Because of its role in bone resorption, it may well play a role in periprosthetic bone loss and aseptic loosening and deserves more detailed study as a mediator and potential target in the modulation or prevention of loosening of THR.

Adolescent↗
PubMed1998

Matrix metalloproteinase (MMP)-9 type IV collagenase/gelatinase implicated in the pathogenesis of Sjögren's syndrome.

Type IV collagenases/gelatinases (matrix metalloproteinases MMP-2 and MMP-9) in labial salivary glands (LSG) and saliva in Sjögren's syndrome (SS) and healthy controls were studied. Zymograms and Western blots disclosed that SS saliva contained 92/82 kD MMP-9/type IV collagenase duplex. Specific activity measurement disclosed 53.1+/-9.8 U/mg protein MMP-9 in SS compared to 16.5+/-2.6 U/mg in healthy controls (p=0.01). MMP-2 did not differ between SS and controls. In SS salivary glands, MMP-2 and MMP-9 were also expressed, in addition to stromal fibroblasts and occasional infiltrating neutrophils, respectively, in acinar end piece cells. In addition, an effective proMMP-9 activator, human trypsin-2 (also known as tumor-associated trypsin-2 or TAT-2), was found in acinar end piece cells and in saliva. Interestingly, proteolytically processed MMP-9 was found in saliva (vide supra), and in vivo activated MMP-9 was significantly higher in SS than in controls (p=0.002). LSGs, particularly in SS, were characterized ultrastructurally by areas containing small cytoplasmic vesicles in the basal parts of the epithelial cells associated with areas of disordered and thickened basal lamina. Based on our results, we conclude here that SS saliva contains increased concentrations of MMP-9, which is of glandular origin in part. Pro MMP-9 is to a large extent proteolytically activated. This is probably mediated by the most potent pro MMP-9 activator found in vivo thus far, namely trypsin-2. Therefore, the MMP 9/trypsin-2 cascade may be responsible for the increased remodelling and/or structural destruction of the basement membrane scaffolding in salivary glands in SS. Due to the role of basal lamina as an important molecular sieve and extracellular matrix-cell signal, these pathological changes may contribute to the pathogenesis of the syndrome.

Blotting, Western↗
PubMed1998

New collagenolytic enzymes/cascade identified at the pannus-hard tissue junction in rheumatoid arthritis: destruction from above.

Our aim was to investigate the collagenolytic potential and localization of matrix metalloproteinase-2 (MMP-2) in relation to its regulatory proteins membrane type MT1-MMP and tissue inhibitor of metalloproteinases-2 (TIMP-2) in rheumatoid arthritis (RA). For this purpose, we have used purification of MMP-2, MMP-8, MMP-9 and interstitial type I, II and III collagens; SDS-PAGE/densitometric collagenase activity assay; zymography; Western blotting; reverse transcriptase polymerase chain reaction; in situ hybridization; and immunofluorescence, ABC, ABC-APAAP double immunostainings. MMP-2 degraded human type II collagen almost as effectively as MMP-8, whereas MMP-9 did not cleave type II collagen. In synovial tissue, MT1-MMP, TIMP-2 and MMP-2 were found in synovial lining in fibroblast- and macrophage-like cells, in stromal cells and in vascular endothelium. MT1-MMP, TIMP-2 and MMP-2 were strongly expressed in the pannocytes of the invasive pannus at the interface, but staining was weak and/or there were few positive cells both "above" and "below" the soft-to-hard tissue (cartilage and/or bone) interface. Rheumatoid synovial tissue extract contained proteolytically active 62/59 kDa MMP-2 and 43 kDa MT1-MMP, but no free TIMP-2. These results indicate that components of the ternary MT1-MMP/TIMP-2/MMP-2 complex are coexpressed in the normal synovial lining and in its pathological extension on the hyaline articular cartilage. MMP-2 may participate in the remodeling of the normal lining and also seems to be localized/focalized to pannocytes at a site critical for tissue destruction in arthritis.

Adult↗
PubMed1998

In vitro sensitivity of the three mammalian collagenases to tetracycline inhibition: relationship to bone and cartilage degradation.

There are at least nine tetracycline (TC) analogs (both antimicrobial and nonantimicrobial) with documented capacity to inhibit, both in vitro and in vivo, the connective tissue degrading activity of matrix metalloproteinases (MMPs). Of the three MMPs that can degrade native helical collagens, MMP-13 (initially identified as rat osteoblast and human breast cancer collagenase, and now known to also be expressed by human cartilage and bone cells) is the most sensitive to TC inhibition (IC50 values in vitro generally less than 1 microgram/mL); the TCs inhibit both the collagenolytic as well as the gelatinolytic activity of this enzyme. The IC50 for MMP-8 (neutrophil collagenase) in vitro ranges from 15 to 86 micrograms/mL depending on assay conditions and choice of TC, whereas inhibition of the fibroblast enzyme (MMP-1) generally requires levels in excess of 200 micrograms/mL (except for CMT-3). The TC compounds that are highly effective against MMP-13 in vitro are also highly inhibitory of glycosaminoglycan release from interleukin-1-stimulated cartilage explants in culture. The current data correlate well with: (i) literature values for TC inhibition of bone resorption by isolated osteoclasts; (ii) inhibition by TCs of avian tibial resorption in organ culture; and (iii) the dramatic ability of TCs to inhibit bone destruction in many rat models (rats have only MMP-8 and MMP-13, and no MMP-1). By carefully selecting a TC-based MMP inhibitor and controlling dosages, it should be possible to inhibit pathologically excessive MMP-8 and/or MMP-13 activity, especially that causing bone erosion, without affecting the constitutive levels of MMP-1 needed for tissue remodeling and normal host function; in this regard, three newly developed CMTs (especially CMT-8, and, to a lesser extent, CMT-3 and -7) appear to be most effective.

Animals↗
PubMed1998

Expression of matrix metalloproteinases (MMP-1 and -2) and their inhibitors (TIMP-1, -2 and -3) in oral lichen planus, dysplasia, squamous cell carcinoma and lymph node metastasis.

Although matrix metalloproteinases (MMPs) are among the potential key mediators of cancer invasion, their involvement in premalignant lesions and conditions is not clarified. Therefore, we studied, using in situ hybridization, immunohistochemistry and zymography the expression and distribution of MMP-1 and -2, and their tissue inhibitors (TIMPs -1, -2 and -3) in oral squamous cell carcinomas (SCC) and lymph node metastases as well as in oral lichen planus, epithelial dysplasias and normal buccal mucosa. In oral SCC and lymph node metastasis, MMP-1 mRNA was detected in fibroblastic cells of tumoral stroma. In two out of ten carcinomas studied, the peripheral cells of neoplastic islands were also positive. MMP-2 mRNA expression was noted in fibroblasts surrounding the carcinoma cells, and no signal in carcinoma cells was detected. A clear TIMP-3 mRNA expression was seen in stromal cells surrounding the neoplastic islands in all SCCs and lymph node metastases studied. TIMP-1 mRNA was detected in some stromal cells surrounding the neoplastic islands, whereas the mRNA expression for TIMP-2 was negligible. On the other hand, expression of MMPs and TIMPs was consistently low in oral epithelial dysplasias, lichen planus and normal mucosa. In certain epithelial dysplasias and lichen planus, MMP-1 and -2 mRNA expressions were detected in few fibroblasts under the basement membrane zone, but normal mucosa was completely negative. In SCC and lymph node metastasis, a detectable immunostaining for MMP-1 in stromal cells and in some carcinoma cells was observed. MMP-2 immunoreactivity was detected in the peripheral cell layer in neoplastic islands and in some fibroblast-like cells of tumoral stroma. Immunostaining for TIMP-3 was detected in stromal cells surrounding the neoplastic islands. A weak positive staining for TIMP-1 was located in tumoral stroma, whereas the immunostaining for TIMP-2 was negative. Using zymography, elevated levels of MMP-2 and MMP-9 were observed in carcinoma samples in comparison with lichen planus or normal oral mucosa. Our results indicate that the studied MMPs and TIMPs are clearly up-regulated during invasion in oral SCC. However, there was also a clear, although weak, up-regulation of the expression of the MMPs but not TIMPs in some of the lichen planus and dysplastic lesions.

Blotting, Western↗
PubMed1998

72-kDa and 92-kDa gelatinases in saliva of patients with human immunodeficiency virus infection.

Human immunodeficiency virus (HIV) infection has been associated with periodontal diseases in HIV-seropositive patients. In periodontal diseases, matrix metalloproteinases (MMPs) may play key roles in the extracellular matrix, basement membrane, serpin degradation, and modification of cytokine action. We characterized the 72 kDa type IV collagenase (gelatinase A, MMP-2) and 92 kDa type IV collagenase (gelatinase B, MMP-9) in the saliva of HIV-seropositive patients and seronegative healthy controls by activity measurements and quantitative immunoblotting. Immunoblot analysis with specific antibodies against MMP-2 and MMP-9 and their tissue inhibitors (TIMP-1, TIMP-2) disclosed that, independent of the phase of the patients' HIV infection, their salivary samples contained higher amounts of MMP-2 and MMP-9 immunoreactivities in pro- and active forms and the TIMP-1 and TIMP-2 inhibitors than did the control samples. Healthy control saliva contained only slight immunoreactivities for gelatinases and TIMPs. However, as judged by the studied clinical and microbiologic indicators, HIV-seropositive patients showed only a slight tendency to develop periodontitis. Overall, an increased amount of gelatinases in saliva may reflect increased host response and defense activities in HIV infection.

Adult↗
PubMed1998

Surface structure, hydrophobicity, phagocytosis, and adherence to matrix proteins of Bacillus cereus cells with and without the crystalline surface protein layer.

Nonopsonic phagocytosis of Bacillus cereus by human polymorphonuclear leukocytes (PMNs) with particular attention to bacterial surface properties and structure was studied. Two reference strains (ATCC 14579(T) and ATCC 4342) and two clinical isolates (OH599 and OH600) from periodontal and endodontic infections were assessed for adherence to matrix proteins, such as type I collagen, fibronectin, laminin, and fibrinogen. One-day-old cultures of strains OH599 and OH600 were readily ingested by PMNs in the absence of opsonins, while cells from 6-day-old cultures were resistant. Both young and old cultures of the reference strains of B. cereus were resistant to PMN ingestion. Preincubation of PMNs with the phagocytosis-resistant strains of B. cereus did not affect the phagocytosis of the sensitive strain. Negatively stained cells of OH599 and OH600 studied by electron microscopy had a crystalline protein layer on the cell surface. In thin-sectioned cells of older cultures (3 to 6 days old), the S-layer was observed to peel off from the cells. No S-layer was detected on the reference strains. Extraction of cells with detergent followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a major 97-kDa protein from the strains OH599 and OH600 but only a weak 97-kDa band from the reference strain ATCC 4342. One-day-old cultures of the clinical strains (hydrophobicity, 5.9 to 6.0%) showed strong binding to type I collagen, laminin, and fibronectin. In contrast, reference strains (hydrophobicity, -1.0 to 4.2%) as well as 6-day-old cultures of clinical strains (hydrophobicity, 19.0 to 53.0%) bound in only low numbers to the proteins. Gold-labelled biotinylated fibronectin was localized on the S-layer on the cell surface as well as on fragments of S-layer peeling off the cells of a 6-day-old culture of B. cereus OH599. Lactose, fibronectin, laminin, and antibodies against the S-protein reduced binding to laminin but not to fibronectin. Heating the cells at 84 degreesC totally abolished binding to both proteins. Benzamidine, a noncompetitive serine protease inhibitor, strongly inhibited binding to fibronectin whereas binding to laminin was increased. Overall, the results indicate that changes in the surface structure, evidently involving the S-layer, during growth of the clinical strains of B. cereus cause a shift from susceptibility to PMN ingestion and strong binding to matrix and basement membrane proteins. Furthermore, it seems that binding to laminin is mediated by the S-protein while binding to fibronectin is dependent on active protease evidently attached to the S-layer.

Bacillus cereus↗
PubMed1998

Expression of tenascin-C in aseptic loosening of total hip replacement.

OBJECTIVE: To assess if the bonding interlayer between the implant and bone in aseptic loosening of total hip replacement (THR) is qualitatively deteriorated by excessive accumulation of anti-adhesive glycoprotein, tenascin-C. METHODS: Alkaline phosphatase-anti-alkaline phosphatase (APAAP) method was used for immunohistochemical staining of tenascin-C in interface tissue and control synovial tissue. RESULTS: Tenascin-C was found to be a major component of the extracellular matrix at a hitherto unrecognised site, namely the synovial membrane-like interface tissue between implant and bone in aseptic loosening of THR. The overall tenascin-C staining (median score 4.0) was greatly increased in aseptic loosening compared with synovial membrane (median score 2.0; p < 0.001) and fibrous capsule (median score 2.0; p < 0.001) from primary THR operations. Topological analysis disclosed that tenascin-C was also found at the critical implant-interface and interface-bone surfaces. CONCLUSION: Local tenascin-C expression is increased as a result of a chronic foreign body type reaction associated with excessive cytokine production and tissue injury mediated by microtrauma and neutral endoproteinases. This qualitative and topological deterioration of the bonding interlayer by an increase of anti-adhesive tenascin-C expression may inadvertantly contribute to loosening.

Aged↗
PubMed1998

The activation and function of host matrix metalloproteinases in dentin matrix breakdown in caries lesions.

Matrix metalloproteinases (MMPs) are a family of enzymes which, in concert, are capable of degrading collagen. We investigated whether human MMPs could participate in the degradation of dentin organic matrix after demineralization. We performed Western blot analyses using MMP-specific antibodies to identify MMPs in human dental caries lesions. Enzymography and functional activity assays, with 125I-labeled gelatin as substrate or quantitating the degradation of type I collagen, were used to determine the activity of purified and salivary gelatinolytic (MMP-2 and MMP-9) and collagenolytic (MMP-8) enzymes with and without acid-activation in pHs relevant to caries. Respective analyses were done with caries-related bacteria. We performed electron microscope analyses to assess the degradative activity of sterilized salivary host MMPs on demineralized human dentin. Human MMP-2, MMP-8, and MMP-9 were identified in demineralized dentinal lesions. The latent purified forms of these enzymes were activated at low pH (4.5), followed by neutralization, mimicking the conditions during caries progression. Incubation of human saliva at low pH followed by neutralization resulted in a four-fold increase in the gelatinolytic activity. No gelatinolytic or collagenolytic activity was observed in bacterial samples. The activated enzymes in saliva degraded demineralized dentin organic matrix in vitro. These results demonstrate the pH-dependent activation mechanism of MMPs, which may have a distinct role in different physiological and pathological conditions. They further demonstrate that host MMPs, activated by bacterial acids, have a crucial role in the destruction of dentin by caries.

Bacterial Proteins↗
PubMed1998

Production of membrane-type matrix metalloproteinase-1 (MT-MMP-1) in early human placenta. A possible role in placental implantation?

The extracellular matrix proteolytic machinery is known to play a major role in trophoblast invasion, a process that shares similar features with the pathology of tumor invasion. In this study we investigated the expression of the recently described membrane-type matrix metalloproteinase-1 (MT-MMP-1; MMP-14) in early human placenta and decidual membrane to determine whether it might play a role in invasion. With in situ hybridization, the cytotrophoblasts of trophoblastic columns and the infiltrating intermediate trophoblasts in the decidual membrane were found to be the main producers of MT-MMP-1 mRNA. Gene expression was also seen in the villous double-layered trophoblastic epithelium and in the decidual cells of the decidual membrane. In endothelial and fibroblastic cells, however, the hybridization signal was either very weak or nonexistent. Immunohistochemical analysis and immunoelectron microscopy correlated well with the in situ hybridization findings. The most significant exception to this consisted of pericytes of spiral arteries, which appeared to lack MT-MMP-1 mRNA but showed intensive intracytoplasmic staining for the antigen. Our results show that MT-MMP-1 mRNA production is highly characteristic of intermediate trophoblasts, and MT-MMP-1 may have general importance in the tissue organization of early human placenta. We propose that MT-MMP-1 could be one of the key enzymes in the process of trophoblast invasion, acting alone or as a cell-surface activator of other proteinases.

Chorionic Villi↗