Expression of metalloproteinases and their tissue inhibitors in inflamed gingival biopsies

Matrix Metalloproteinases in the Periodontium-Vital in Tissue Turnover and Unfortunate in Periodontitis

The extracellular matrix (ECM) is a complex non-cellular three-dimensional macromolecular network present within all tissues and organs, forming the foundation on which cells sit, and composed of proteins (such as collagen), glycosaminoglycans, proteoglycans, minerals, and water. The ECM provides a fundamental framework for the cellular constituents of tissue and biochemical support to surrounding cells. The ECM is a highly dynamic structure that is constantly being remodeled. Matrix metalloproteinases (MMPs) are among the most important proteolytic enzymes of the ECM and are capable of degrading all ECM molecules. MMPs play a relevant role in physiological as well as pathological processes; MMPs participate in embryogenesis, morphogenesis, wound healing, and tissue remodeling, and therefore, their impaired activity may result in several problems. MMP activity is also associated with chronic inflammation, tissue breakdown, fibrosis, and cancer invasion and metastasis. The periodontium is a unique anatomical site, composed of a variety of connective tissues, created by the ECM. During periodontitis, a chronic inflammation affecting the periodontium, increased presence and activity of MMPs is observed, resulting in irreversible losses of periodontal tissues. MMP expression and activity may be controlled in various ways, one of which is the inhibition of their activity by an endogenous group of tissue inhibitors of metalloproteinases (TIMPs), as well as reversion-inducing cysteine-rich protein with Kazal motifs (RECK).

Matrix Metalloproteinase Activity in Gingival Crevicular Fluid and Periodontal Health Status in Down Syndrome Patients: A Comparative Study

Introduction Periodontal diseases, caused by gram-negative bacteria, often begin as gingivitis and can progress to periodontitis, characterized by inflammation extending to the periodontal ligament and alveolar bone. Individuals with Down syndrome (DS) commonly exhibit poorer oral hygiene and a higher prevalence of severe chronic periodontitis. This study aimed to identify unregulated risk factors in DS that contribute to increased periodontal breakdown. Materials and methods We conducted a study with 60 age-matched patients, including 20 DS patients from Balavihar Special School and 40 systemically healthy patients with and without periodontitis from Thai Moogambigai Dental College and Hospital. We collected patients' complete case histories and blood samples for evaluating matrix metalloproteinase 8 (MMP8) and matrix metalloproteinase 9 (MMP9) levels. All patients underwent nonsurgical periodontal therapy, and the samples were processed at the Central Research Laboratory at Meenakshi Ammal Dental College and Hospital. We calculated each group's mean and standard deviation and compared them using one-way analysis of variance and Kruskal-Wallis tests, followed by post hoc (Tukey honestly significant difference) multiple group comparisons. Statistical analysis was performed using Statistical Product and Service Solutions (SPSS) Statistics for Windows, Version 17.0. (Chicago: SPSS Inc.). Results The mean value of MMP8 in the DS group with chronic periodontitis was -18.1895, which was statistically significant (P<.001) compared to the mean value of -20.3720 in systemically healthy subjects with chronic periodontitis and -21.7120 in systemically healthy controls. Similarly, the mean value of MMP9 in the DS group with chronic periodontitis was 18.6455, which was statistically significant (P<.001) compared to the mean values of 19.8540 in systemically healthy subjects with chronic periodontitis and 25.2505 in systemically healthy controls. These findings indicate that DS subjects exhibit increased levels of pro-inflammatory cytokines MMP8 and MMP9, serving as markers for identifying periodontal disease. The mean differences in MMP8 and MMP9 in the DS group with chronic periodontitis showed highly statistically significant levels compared to both systemically healthy groups. Conclusion This study aimed to identify unregulated risk factors in DS that contribute to increased periodontal breakdown. Our findings revealed elevated MMP8 and MMP9 in DS patients with periodontitis, indicating an increased risk for early development of destructive forms of periodontal disease in this population. Extensive gingival tissue inflammation, bleeding on probing, increasing probing depths, loss of periodontal attachment, and alveolar bone loss are all common symptoms.

Expression of matrix metalloproteinase-9 in gingival tissue biopsy in patients with slowly/ moderately and rapidly progressing periodontitis: An observational study

Background

Matrix metalloproteinases (MMPs) are a group of host-derived zinc-dependent enzymes which mediates the destruction of the extracellular matrix. In periodontitis, there is excess production of MMPs associated with periodontal tissue destruction. The aim of this study was to estimate the level MMP-9 in both active and latent form in gingival tissue (GT) samples collected from periodontitis patients with different rates of progression and compare it with healthy individuals.

Materials and Methods

Sixty patients were selected and divided into three groups, 20 each: Group A (slowly/moderately progressing periodontitis), Group B (rapidly progressing periodontitis), and Group C (clinical periodontal health). Plaque index, gingival index, periodontal probing depth (PPD), and clinical attachment level were recorded. GT samples were collected from all 60 patients and MMP-9 expressions were measured using gelatin zymography and western blotting.

Results

Levels of active MMP-9 (aMMP-9) and latent MMP-9 (lMMP-9) were significantly high in both Group A (GA) (aMMP-9: 2.05 arbitrary unit [AU]/lMMP-9: 2.54 AU) and Group B (GB) (aMMP-9: 1.32 AU/lMMP-9: 1.74 AU) when compared to that of Group C (GC) (aMMP-9: 0.93/lMMP-9: 1.08 AU). In GA, levels of aMMP-9 showed a significant correlation with PPD values. No other correlations were found.

Conclusion

The levels of aMMP-9 and lMMP-9 were increased in both the types of periodontitis when compared with periodontally healthy individuals. A significant correlation was found between PPD and activities of aMMP-9 in slowly/moderately progressing periodontitis patients. However, further studies are required to confirm these findings.

Porphyromonas gingivalis lipopolysaccharide and gingival fibroblast augment MMP-9 expression of monocytic U937 cells through cyclophilin A

BACKGROUND

Intercellular cross-talking was suggested in matrix metalloproteinase (MMP)-9 expression with unknown mechanisms. Studies showed cyclophilin A (CypA) playing an important role in regulating MMP-9 expression in varied diseases. The aim of the study was to examine the CyPA on the MMP-9 augmentation in monocytic U937 cells after Porphyromonas gingivalis (Pg) lipopolysaccharide (LPS) treatment and human gingival fibroblast (hGF) co-culture.

METHODS

In independent culture or co-culture of hGF and U937 cell, quantitative real-time polymerase chain reaction (qPCR) and zymography were selected to examine the mRNA and protein activity of MMP-9, respectively. The CyPA expression was determined by qPCR.

RESULTS

LPS could enhance MMP-9 mRNA expression and enzyme activity in U937 cell. However, the enhancements were not observed in hGF. Similarly, LPS enhanced CyPA mRNA in U937, but not in hGF. After co-cultured with hGF, however, MMP-9 and CyPA in U937 increased regardless of the presence/absence of LPS. In U937 cells, the extra-supplied CyPA increased MMP-9 mRNA and enzyme activity, whereas the CyPA inhibitor, cyclosporine A, suppressed the LPS- and co-culture-enhanced MMP-9. Moreover, the inhibitors for MAP kinase, including PD98059 (ERK) and SP600125 (JNK), suppressed the CyPA-enhanced MMP-9 in U937.

CONCLUSION

Through the CyPA pathway, the LPS and the hGF could augment the MMP-9 expression in the U937 cells.

CD147 self-regulates matrix metalloproteinase-2 release in gingival fibroblasts after coculturing with U937 monocytic cells

BACKGROUND

Cluster of differentiation 147 (CD147) is a multifunctional glycoprotein that functions as an inducer of matrix metalloproteinase (MMP) expression in fibroblasts. Synergistically enhanced MMP-2 expression was recently observed in the coculture of human gingival fibroblasts (HGFs) and U937 human monocytic cells; however, the responsible mechanisms have not yet been fully established. The aim of this study was to evaluate the release of soluble CD147 in HGFs after coculturing with U937 cells and its functional effect on the enhancement of MMP-2 expression in HGFs.

METHODS

Enzyme-linked immunosorbent assay was used to determine the amount of CD147 protein in media, whereas real-time polymerase chain reaction was performed to evaluate the mRNA levels of CD147 and MMP-2 in HGFs and U937 cells. The enzyme activities of MMP-2 released from cells were examined by zymography. Transwell coculturing and conditioned media treatments were selected to rule out the effect of direct contact of HGFs and U937 cells.

RESULTS

The protein and mRNA expression of CD147 in HGFs were enhanced after transwell coculturing with U937 cells and exposure to U937-conditioned medium. MMP-2 enzyme activities in HGFs were also significantly increased by the coculturing methods. Administration of exogenous CD147 enhanced MMP-2 expression in HGFs, whereas treatment with cyclosporine-A, which inhibited CD147 expression, reduced U937-enhanced MMP-2 expression in HGFs.

CONCLUSIONS

CD147 can interact with fibroblasts to stimulate the expression of MMPs associated with periodontal extracellular matrix degradation. This study has demonstrated that CD147 released from fibroblasts might play a role in monocyte-enhanced MMP-2 expression in HGFs.

The novel role of HtrA1 in gingivitis, chronic and aggressive periodontitis

Proteolytic tissue degradation is a typical phenomenon in inflammatory periodontal diseases. HtrA1 (High temperature requirement A 1) has a serine protease activity and is able to degrade fibronectin whose fragments induce the expression and secretion of several matrix metalloproteinases (MMPs). The aim of this study was to investigate for the first time if HtrA1 has a role in gingivitis and in generalized forms of chronic and aggressive periodontitis. Expression of HtrA1 was investigated in 16 clinically healthy gingiva, 16 gingivitis, 14 generalized chronic periodontitis and 10 generalized aggressive periodontitis by immunohistochemistry and real-time PCR. Statistical comparisons were performed by the Kruskall-Wallis test. Significantly higher levels of HtrA1 mRNA and protein expression were observed in pathological respect to healthy tissues. In particular, we detected an increase of plasma cell HtrA1 immunostaining from gingivitis to chronic and aggressive periodontitis, with the higher intensity in aggressive disease. In addition, we observed the presence of HtrA1 in normal and pathological epithelium, with an increased expression, particularly in its superficial layer, associated with increasingly severe forms of periodontal disease. We can affirm that HtrA1 expression in plasma cells could be correlated with the destruction of pathological periodontal tissue, probably due to its ability to trigger the overproduction of MMPs and to increase the inflammatory mediators TNF-α and IL-1β by inhibition of TGF-β. Moreover, epithelial HtrA1 immunostaining suggests a participation of the molecule in the host inflammatory immune responses necessary for the control of periodontal infection.

Full inactivation of human influenza virus by high hydrostatic pressure preserves virus structure and membrane fusion while conferring protection to mice against infection

Whole inactivated vaccines (WIVs) possess greater immunogenicity than split or subunit vaccines, and recent studies have demonstrated that WIVs with preserved fusogenic activity are more protective than non-fusogenic WIVs. In this work, we describe the inactivation of human influenza virus X-31 by high hydrostatic pressure (HHP) and analyze the effects on the structure by spectroscopic measurements, light scattering, and electron microscopy. We also investigated the effects of HHP on the glycoprotein activity and fusogenic activity of the viral particles. The electron microscopy data showed pore formation on the viral envelope, but the general morphology was preserved, and small variations were seen in the particle structure. The activity of hemagglutinin (HA) during the process of binding and fusion was affected in a time-dependent manner, but neuraminidase (NA) activity was not affected. Infectious activity ceased after 3 hours of pressurization, and mice were protected from infection after being vaccinated. Our results revealed full viral inactivation with overall preservation of viral structure and maintenance of fusogenic activity, thereby conferring protection against infection. A strong response consisting of serum immunoglobulin IgG1, IgG2a, and serum and mucosal IgA was also detected after vaccination. Thus, our data strongly suggest that applying hydrostatic pressure may be an effective method for developing new vaccines against influenza A as well as other viruses.

Mast cells and MMP-9 in the lamina propria during eruption of rat molars: quantitative and immunohistochemical evaluation

During the active tooth eruption process, structural changes in the lamina propria are necessary to provide extracellular matrix remodelling and for the establishment of the eruptive pathway. A large number of resident cells, recruited cells and proteases have been demonstrated in the eruptive process, but the participation of MMP-9 and mast cells has not yet been demonstrated. In this study, we set out to evaluate the intensity of MMP-9 immunoexpression, the frequency of mast cells and the correlation between the incidence of mast cells and bone resorption in different phases of tooth eruption. Fragments of maxilla containing first molars, obtained from 9-, 11-, 13- and 16-day-old rats, were fixed in 4% formaldehyde, decalcified and embedded in paraffin. Sagittal sections were stained with Masson's trichrome or submitted to the tartrate-resistant acid phosphatase method for quantification of osteoclasts. Sections stained by 1% toluidine blue were used for quantification of metachromatic mast cells mm(-2) of lamina propria. The expression of MMP-9 in the lamina propria was evaluated by immunohistochemistry. In the 9-day-old rats, the lamina propria contained few mast cells and occasional osteoclasts were found in the bone surface overlying the occlusal portion of the tooth germs. Otherwise, a significant increase in the number of mast cells was observed in the intra-osseous phase of tooth eruption (11-day-old rats), period in which numerous TRAP-positive osteoclasts were found in the bone surface. MMP-9 immunolabelling was detected in fibroblasts, mast cells and macrophage-like cells of the lamina propria in all ages studied. However, an enhanced immunolabelling was evident in the advanced phase of tooth eruption (16-day-old rats). During the intra-osseous phase, the parallel between the high frequency of both mast cells and osteoclasts suggests that mast cells could exert a paracrine function on the osteoclasts and then stimulate bone resorption. The immunoexpression of MMP-9 in different cells of lamina propria, including mast cells, indicates that this enzyme participates in the degradation of ECM, mainly during late phase of mucosal penetration. Thus mast cells and MMP-9 are involved in the complex process of degradation of the eruptive pathway extracellular matrix.