Chondrocyte matrix metalloproteinase-8. Human articular chondrocytes express neutrophil collagenase

In Vivo Regulation of Active Matrix Metalloproteinase-8 (aMMP-8) in Periodontitis: From Transcriptomics to Real-Time Online Diagnostics and Treatment Monitoring

BACKGROUND

This study investigated in vivo regulation and levels of active matrix metalloproteinase-8 (aMMP-8), a major collagenolytic protease, in periodontitis.

METHODS

Twenty-seven adults with chronic periodontitis (CP) and 30 periodontally healthy controls (HC) were enrolled in immunohistochemistry and transcriptomics analytics in order to assess Treponema denticola (Td) dentilisin and MMP-8 immunoexpression, mRNA expression of MMP-8 and its regulators (IL-1β, MMP-2, MMP-7, TIMP-1). Furthermore, the periodontal anti-infective treatment effect was monitored by four different MMP-8 assays (aMMP-8-IFMA, aMMP-8-Oralyzer, MMP-8-activity [RFU/minute], and total MMP-8 by ELISA) among 12 CP (compared to 25 HC).

RESULTS

Immunohistochemistry revealed significantly more Td-dentilisin and MMP-8 immunoreactivities in CP vs. HC. Transcriptomics revealed significantly elevated IL-1β and MMP-7 RNA expressions, and MMP-2 RNA was slightly reduced. No significant differences were recorded in the relatively low or barely detectable levels of MMP-8 mRNAs. Periodontal treatment significantly decreased all MMP-8 assay levels accompanied by the assessed clinical indices (periodontal probing depths, bleeding-on-probing, and visual plaque levels). However, active but not total MMP-8 levels persisted higher in CP than in periodontally healthy controls.

CONCLUSION

In periodontal health, there are low aMMP-8 levels. The presence of Td-dentilisin in CP gingivae is associated with elevated aMMP-8 levels, potentially contributing to a higher risk of active periodontal tissue collagenolysis and progression of periodontitis. This can be detected by aMMP-8-specific assays and online/real-time aMMP-8 chair-side testing.

Graphene Hydrogel as a Porous Scaffold for Cartilage Regeneration

Porous scaffolds have widely been exploited in cartilage tissue regeneration. However, it is often difficult to understand how the delicate hierarchical structure of the scaffold material affects the regeneration process. Graphene materials are versatile building blocks for robust and biocompatible porous structures, enabling investigation of structural cues on tissue regeneration otherwise challenging to ascertain. Here, we utilize a graphene hydrogel with stable and tunable structure as a model scaffold to examine the effect of porous structure on matrix remodeling associated with ingrowth of chondrocytes on scaffolds. We observe much-accelerated yet balanced cartilage remodeling correlating the ingrowth of chondrocytes into the graphene scaffold with an open pore structure on the surface. Importantly, such an enhanced remodeling selectively promotes the expression of collagen type II fibrils over proteoglycan aggrecan, hence clearly illustrating that chondrocytes maintain a stable phenotype when they migrate into the scaffold while offering new insights into scaffold design for cartilage repair.

Cellular responses in the FGF10-mediated improvement of hindlimb regenerative capacity in Xenopus laevis revealed by single-cell transcriptomics

Xenopus laevis tadpoles possess regenerative capacity in their hindlimb buds at early developmental stages (stages ~52-54); they can regenerate complete hindlimbs with digits after limb bud amputation. However, they gradually lose their regenerative capacity as metamorphosis proceeds. Tadpoles in late developmental stages regenerate fewer digits (stage ~56), or only form cartilaginous spike without digits or joints (stage ~58 or later) after amputation. Previous studies have shown that administration of fibroblast growth factor 10 (FGF10) in late-stage (stage 56) tadpole hindlimb buds after amputation can improve their regenerative capacity, which means that the cells responding to FGF10 signaling play an important role in limb bud regeneration. In this study, we performed single-cell RNA sequencing (scRNA-seq) of hindlimb buds that were amputated and administered FGF10 by implanting FGF10-soaked beads at a late stage (stage 56), and explored cell clusters exhibiting a differential gene expression pattern compared with that in controls treated with phosphate-buffered saline. The scRNA-seq data showed expansion of fgf8-expressing cells in the cluster of the apical epidermal cap of FGF10-treated hindlimb buds, which was reported previously, indicating that the administration of FGF10 was successful. On analysis, in addition to the epidermal cluster, a subset of myeloid cells and a newly identified cluster of steap4-expressing cells showed remarkable differences in their gene expression profiles between the FGF10- or phosphate-buffered saline-treatment conditions, suggesting a possible role of these clusters in improving the regenerative capacity of hindlimbs via FGF10 administration.

Integrative analyses of genes related to femoral head osteonecrosis: an umbrella review of systematic reviews and meta-analyses of observational studies

Background

Femoral head osteonecrosis (FHON) is a worldwide challenging clinical topic. Steroid use is one of the main etiologies of FHON. There are several genetic variants associated with FHON. Therefore, the purpose of this umbrella review was to provide a comprehensive summary of a meta-analysis and systematic review of genetic variations associated with nonsteroidal and steroid-induced FHON.

Methods

The eligible studies were selected from the PubMed and MEDLINE databases for the collection of diverse systematic meta-analyses and reviews. The genetic main effect score was assigned using the Human Genome Epidemiology Network’s Venice criteria to assess the cumulative evidence on the effects of a single nucleotide polymorphism (SNP) on FHON.

Results

Eight articles reported the meta-analysis of candidate SNP-based studies covering eight genes and 13 genetic variants. In the nonsteroid-induced FHON genetic variants including rs2012390 and rs11225394 in MMP8, rs1800629 and rs361525 in tumor necrosis factor (TNF)-α, VNTR in intron 4, rs1799983 and rs2070744 in endothelial nitric oxide synthase (eNOS), rs2010963 in vascular endothelial growth factor (VEGF), and rs6025 in factor V showed significance in each reference. The steroid-induced FHON genetic variants including rs693 and rs1042031 in apolipoprotein (Apo)B, rs1045642 in ABCB1, and rs1799889 in PAI-1 showed significance in each reference.

Conclusion

Based on the systematic review conducted in this study, we organized the genomes associated with FHON and looked at each contribution. Our results could give an integrative approach for understanding the mechanism of FHON etiology. It is expected that these results could contribute to the strategy of prediagnosis, evaluating the individual risk of nonsteroid-induced and steroid-induced FHON.

Level of Evidence: Level I.

Targeting Dysregulation of Metalloproteinase Activity in Osteoarthritis

Metalloproteinases were first identified as collagen cleaving enzymes and are now appreciated to play important roles in a wide variety of biological processes. The aberrant activity and dysregulation of the metalloproteinase family are linked to numerous diseases including cardiovascular and pulmonary diseases, chronic wounds, cancer, fibrosis and arthritis. Osteoarthritis (OA) is the most prevalent age-related joint disorder that causes pain and disability, but there are no disease-modifying drugs available. The hallmark of OA is loss of articular cartilage and elevated activities of matrix-degrading metalloproteinases are responsible. These enzymes do not exist in isolation and their activity is tightly regulated by a number of processes, such as transcription, proteolytic activation, interaction with their inhibitors, cell surface and extracellular matrix molecules, and endocytic clearance from the extracellular milieu. Here, we describe the functions and roles of metalloproteinase family in OA pathogenesis. We highlight recent studies that have illustrated novel mechanisms regulating their extracellular activity and impairment of such regulations that lead to the development of OA. We also discuss how to stop or slow down the degenerative processes by targeting aberrant metalloproteinase activity, which may in future become therapeutic interventions for the disease.

Mechanisms of toxicity mediated by neutrophil and eosinophil granule proteins

Neutrophils and eosinophils are granulocytes which are characterized by the presence of granules in the cytoplasm. Granules provide a safe storage site for granule proteins that play important roles in the immune function of granulocytes. Upon granulocytes activation, diverse proteins are released from the granules into the extracellular space and contribute to the fight against infections. In this article, we describe granule proteins of both neutrophils and eosinophils able to kill pathogens and review their anticipated mechanism of antimicrobial toxicity. It should be noted that an excess of granules protein release can lead to tissue damage of the host resulting in chronic inflammation and organ dysfunction.

Evaluation of Salivary Matrix Metalloproteinase (MMP-8) in Periodontal Patients Undergoing Non-Surgical Periodontal Therapy and Mouthwash Based on Ozonated Olive Oil: A Randomized Clinical Trial

Background: Extracellular matrix metalloproteinases (MMPs) play a pivotal role in the damage to the periodontal tissue in patients with periodontitis. Scaling and root planning (SRP) attempt to control the plaque amount and consequentially reduce the bacterial load. Non-surgical periodontal treatment could be integrated with drug therapy and physiotherapy procedures such as ozone therapy. The aim of this study was to evaluate in a cohort of patients with a diagnosis of periodontitis: (1) the efficacy of non-surgical periodontal therapy assisted by the use of ozonated olive oil-based mouthwash on salivary metalloproteinase (MMP-8) and (2) the reduction of periodontal indices. Methods: Ninety-six subjects with a diagnosis of periodontitis were enrolled in this study and randomly assigned to the study group (SRP + mouthwash) or control group (SRP). The study duration was 3 months. Data on MMP-8, plaque index (PI), bleeding on probing (BoP) and probing pocket depth (PPD) were recorded at T0, T1 (14 days), T2 (1 month) and T3 (6 months). Group differences were assessed using Student's t-test for independent samples. Results: A significant improvement in PI, BoP, PPD and salivary MMP-8 levels was observed in both groups. An analysis of differences in relative changes of indices revealed the efficacy of ozonated olive oil in decreasing MMP-8 level. Simultaneously, it slowed the decrease of BoP index. Conclusions: Scaling and root plaining with the aid of ozonated olive oil mouthwash were found to be more effective on salivary MMP-8 reduction than scaling and root plaining alone.

Association of MMP-8 rs2012390 and rs11225394 polymorphisms with osteonecrosis of the femoral head risks: Evidence from a meta-analysis

BACKGROUND

The association of MMP-8 rs2012390 and rs11225394 polymorphisms with osteonecrosis of the femoral head (ONFH) risks was investigated in several studies with conflicting results. We performed the meta-analysis to evaluate the association between them.

METHODS

Potentially relevant literatures were searched from the electronic databases of PubMed, Web of Science, and Cochrane Library. All databases were searched up to May 6, 2018. The strength of associations of the MMP-8 rs2012390 and rs11225394 polymorphisms with ONFH risk was assessed by crude odds ratios (ORs) with their 95% confidence intervals (CIs) under different genetic models.

RESULTS

A total of 1469 cases diagnosed with ONFH and 1211 healthy controls were included in the current meta-analysis. A remarkable association between rs11225394 in the MMP-8 gene and an increased risk of ONFH was found (allele model: OR = 1.33, 95% CI = 1.09-1.61, P = .005; heterozygote model: OR = 1.39, 95% CI = 1.13-1.71, P = .002; dominant model: OR = 1.40, 95% CI = 1.14-1.73, P = .002, respectively). Meanwhile, a significant association between MMP-8 rs2012390 and the decreased risk of ONFH was found in heterozygote model (OR = 0.63, 95% CI = 0.51-0.77, P < .00001).

CONCLUSION

The meta-analysis results showed a remarkable association between rs11225394 in MMP-8 gene and an increased risk of ONFH and a significant association between MMP-8 rs2012390 and the decreased risk of ONFH.

MMP-3 and MMP-8 single-nucleotide polymorphisms are related to alcohol-induced osteonecrosis of the femoral head in Chinese males

Our study investigated the association between MMP-3 and MMP-8 single-nucleotide polymorphisms (SNPs) and alcohol-induced osteonecrosis of the femoral head (ONFH) in 695 Chinese males (299 cases and 396 control subjects). The minor allele of MMP-3 rs650108 was associated with a 0.78-fold decrease in alcohol-induced ONFH risk in the allelic model (95% CI = 0.63-0.97, P = 0.026). In the genetic model adjusted for age, rs650108 was associated with decreased risk of alcohol-induced ONFH in the dominant model (OR = 0.68, 95% CI = 0.49-0.95, P = 0.022) and log-additive model (OR = 0.78, 95% CI = 0.63-0.98, P = 0.030); MMP-8 rs11225394 was associated with increased risk in the codominant model (OR = 1.72, 95% CI = 1.15-2.58, P= 0.010), dominant model (OR = 1.67, 95% CI = 1.12-2.48, P = 0.012), over-dominant model (OR = 1.73, 95% CI = 1.16-2.59, P = 0.007) and log-additive model (OR = 1.57, 95% CI= 1.07-2.32, P = 0.022); and MMP-8 rs2012390 was associated with decreased risk in the dominant model (OR = 0.72, 95% CI = 0.53-0.97, P = 0.032) and log-additive model (OR = 0.77, 95% CI = 0.60-0.98, P = 0.035). Haplotype analysis showed that the CGATATGT sequence mediated decreased alcohol-induced ONFH risk (OR = 0.75, 95% CI = 0.57-0.97, P = 0.029). Therefore, among Chinese males, MMP-3 rs650108 and MMP-8 rs2012390 decrease alcohol-induced ONFH risk and MMP-8 rs11225394 increases it. Further study is needed to validate our conclusion.

Osteogenic Potential of the Transcription Factor c-MYB

The transcription factor c-MYB is a well-known marker of undifferentiated cells such as haematopoietic cell precursors, but recently it has also been observed in differentiated cells that produce hard tissues. Our previous findings showed the presence of c-MYB in intramembranous bones and its involvement in the chondrogenic steps of endochondral ossification, where the up-regulation of early chondrogenic markers after c-myb overexpression was observed. Since we previously detected c-MYB in osteoblasts, we aimed to analyse the localisation of c-MYB during later stages of endochondral bone formation and address its function during bone matrix production. c-MYB-positive cells were found in the chondro-osseous junction zone in osteoblasts of trabecular bone as well as deeper in the zone of ossification in cells of spongy bone. To experimentally evaluate the osteogenic potential of c-MYB during endochondral bone formation, micromasses derived from embryonic mouse limb buds were established. Nuclear c-MYB protein expression was observed in long-term micromasses, especially in the areas around nodules. c-myb overexpression induced the expression of osteogenic-related genes such as Bmp2, Comp, Csf2 and Itgb1. Moreover, alizarin red staining and osteocalcin labelling promoted mineralised matrix production in c-myb-overexpressing cultures, whereas downregulation of c-myb by siRNA reduced mineralised matrix production. In conclusion, c-Myb plays a role in the osteogenesis of long bones by inducing osteogenic genes and causing the enhancement of mineral matrix production. This action of the transcription factor c-Myb might be of interest in the future for the establishment of novel approaches to tissue regeneration.

Serum and salivary matrix metalloproteinases, neutrophil elastase, myeloperoxidase in patients with chronic or aggressive periodontitis

Salivary, serum matrix metalloproteinase-8 (MMP-8), tissue inhibitor of matrix metalloproteinases-1 (TIMP-1), neutrophil elastase (NE), and myeloperoxidase (MPO) levels were investigated in generalized chronic periodontitis (GCP), generalized aggressive periodontitis (GAgP), and healthy groups. Whole-mouth clinical periodontal measurements were recorded. Salivary, serum concentrations of MMP-8, MPO, TIMP-1, and NE were determined by immunofluorometric assay or ELISA in 18 patients with GCP, 23 patients with GAgP, 18 individuals with healthy periodontium. Patients in the GAgP group were younger than the other groups (p<0.05). The study groups were similar in gender, smoking status. Plaque index was higher in GCP than GAgP group (p<0.05). Biochemical data were similar in periodontitis groups. Salivary, serum MPO, and salivary NE concentrations were higher; TIMP-1 concentrations were lower in the periodontitis groups than the controls (p<0.05). The present data support a close relationship between salivary, serum protease content and clinical periodontal parameters in patients with generalized periodontitis.

Development of a cellularly degradable PEG hydrogel to promote articular cartilage extracellular matrix deposition

Healing articular cartilage remains a significant clinical challenge because of its limited self-healing capacity. While delivery of autologous chondrocytes to cartilage defects has received growing interest, combining cell-based therapies with scaffolds that capture aspects of native tissue and promote cell-mediated remodeling could improve outcomes. Currently, scaffold-based therapies with encapsulated chondrocytes permit matrix production; however, resorption of the scaffold does not match the rate of production by cells leading to generally low extracellular matrix outputs. Here, a poly (ethylene glycol) (PEG) norbornene hydrogel is functionalized with thiolated transforming growth factor (TGF-β1) and cross-linked by an MMP-degradable peptide. Chondrocytes are co-encapsulated with a smaller population of mesenchymal stem cells, with the goal of stimulating matrix production and increasing bulk mechanical properties of the scaffold. The co-encapsulated cells cleave the MMP-degradable target sequence more readily than either cell population alone. Relative to non-degradable gels, cellularly degraded materials show significantly increased glycosaminoglycan and collagen deposition over just 14 d of culture, while maintaining high levels of viability and producing a more widely-distributed matrix. These results indicate the potential of an enzymatically degradable, peptide-functionalized PEG hydrogel to locally influence and promote cartilage matrix production over a short period. Scaffolds that permit cell-mediated remodeling may be useful in designing treatment options for cartilage tissue engineering applications.

Melittin has a chondroprotective effect by inhibiting MMP-1 and MMP-8 expressions via blocking NF-κB and AP-1 signaling pathway in chondrocytes

Bee venom is a natural ingredient produced by the honey bee (Apis mellifera), and has been widely used in China, Korea and Japan as a traditional medicine for various diseases such as arthritis, rheumatism, and skin diseases However, the regulation of the underlying molecular mechanisms of the anti-arthritis by bee venom and its major peptides is largely unknown. In this study, we investigated the potential molecular mechanisms underlying the anti-arthritis effect of bee venom and its major peptides, melittin and apamin, in tumor necrosis factor-α (TNF-α) responsive C57BL/6 mice chondrocyte cells. The bee venom and melittin significantly and selectively suppressed the TNF-α-mediated decrease of type II collagen expression, whereas the apamin had no effects on the type II collagen expression. We, furthermore, found that the bee venom and melittin inhibited the protein expression of matrix metalloproteinase (MMP)-1 and MMP-8, which suggests that the chondroprotective effect of bee venom may be caused by melittin. The inhibitory effects of melittin on the TNF-α-induced MMP-1 and MMP-8 protein expression were regulated by the inhibition of NF-kB and AP-1. In addition, melittin suppressed the TNF-α-induced phosphorylation of Akt, JNK and ERK1/2, but did not affect the phosphorylation of p38 kinase. These results suggest that melittin suppresses TNF-α-stimulated decrease of type II collagen expression by the inhibiting MMP-1 and MMP-8 through regulation of the NF-kB and AP-1 pathway and provision of a novel role for melittin in anti-arthritis action.

Glycogen synthase kinase 3 inhibition stimulates human cartilage destruction and exacerbates murine osteoarthritis

OBJECTIVE

To assess the role of glycogen synthase kinase 3 (GSK-3) as a regulator of cartilage destruction in human tissue and a murine model of osteoarthritis (OA).

METHODS

Surgical destabilization of the medial meniscus (DMM) was performed to induce experimental murine OA, and joint damage was assessed histologically. Bovine nasal and human OA cartilage samples were incubated with interleukin-1 (IL-1) plus oncostatin M (OSM) and GSK-3 inhibitor. Collagen and proteoglycan release was assessed by hydroxyproline measurement and dye binding assay, collagenase activity was assessed by bioassay, and gene expression was analyzed by real-time polymerase chain reaction. Human articular chondrocytes were isolated by enzymatic digestion and cultured prior to gene silencing and immunoblotting of cell lysates and nuclear fractions.

RESULTS

Mice treated with GSK-3 inhibitor exhibited significantly greater cartilage damage compared with sham-operated control mice. GSK-3 inhibition in bovine cartilage dramatically accelerated IL-1 plus OSM-stimulated degradation, concomitant with a profound increase in collagenase activity. GSK-3 inhibitor induced collagen release from human OA cartilage in the presence of IL-1 plus OSM and increased proteoglycan loss. Gene expression profiling of resorbing OA cartilage revealed a marked procatabolic switch in gene expression upon GSK-3 inhibition. This was mirrored in human articular chondrocytes following GSK3 silencing, particularly with the GSK-3β isoform. GSK-3 inhibition or silencing led to enhanced IL-1 plus OSM-stimulated abundance and activity of Jun, and silencing of c-jun ameliorated GSK-3 inhibitor-mediated procatabolic gene expression.

CONCLUSION

GSK-3 is an important regulator of matrix metalloproteinase (MMP)-mediated joint destruction, the inhibition of which by proinflammatory stimuli de-represses catabolic gene expression. Therapeutic strategies that maintain cartilage GSK-3 activity may therefore help curtail aberrant MMP activity during pathologic joint destruction.

Association of matrix metalloproteinase 8 genetic polymorphisms with bronchial asthma in a Japanese population

Asthma has a strong genetic component. The final disease phenotype results from complex interactions between environment and multiple genes of small-to-modest effects. We investigated whether the polymorphism in genes encoding inflammatory mediators and cytokines is important for solving the onset and progression of asthma. We investigated whether 31 single nucleotide polymorphisms (SNPs) in genes encoding cytokines or monokines (interleukin [IL]-5R, matrix metalloproteinase [MMP] 8, beta2 adrenergic receptor, cytotoxic T-lymphocyte–associated antigen 4, IL-3, C-reactive protein, cytochrome P450 (CYP) 2C9, CYP3A4, a disintegrin and metalloproteinase [ADAM] 33, cysteinyl leukotriene receptor [CysLTR] 1, CysLTR2, eosinophilic cationic protein, glucocorticoid receptor, and leukotriene A 4 hydrolase) are related to asthma development in 206 Japanese bronchial asthma patients and 127 healthy controls. Using multifactor dimensionality reduction (MDR), we identified rs17099451 in MMP8, using a single locus model, with a mean cross-validation of 87.0%. Using a two-locus model, combinations of MMP8 and rs44707 in ADAM33, and MMP8 and rs40401 in IL-3, were identified, with mean cross-validation consistencies reaching 45.0%. Of the SNPs selected by the MDR method, rs17099451 in MMP8 and rs40401 in IL-3 were regarded as the most significant results in a 2 × 2 dominant model analysis. The finding that an MMP8 allele was most strongly related to asthma development indicates that metalloproteinase function is crucial to the airflow limitation process involved in this disease.

Influence of MMP-8 promoter polymorphism in early osseointegrated implant failure

OBJECTIVE

Dental implants consist in the treatment of choice to replace tooth loss. The knowledge that implant loss tends to cluster in subsets of individuals may indicate that host immuneinflammatory response is influenced by genetic factors. In fact, genetic polymorphisms influence the osseointegration process. The objective of this study was investigate the possible relationship between C-799T polymorphism in matrix metalloproteinase 8 (MMP-8) gene and early implant failure in nonsmoker patients.

METHODS AND MATERIALS

Subjects were divided into two groups: control group (100 patients with one or more healthy implants) and test group (80 patients that had suffered one or more early implant failures). Genomic DNA from oral mucosa was amplified by PCR and analyzed by restriction endonucleases. The significance of the differences in observed frequencies of polymorphisms was assessed by Chi-square.

RESULTS

Statistical analysis shows that in the MMP-8 gene, the T allele in 76.25% in the test group and the T/T genotype, 63.75% in the same group, may predispose to early loss of implants osseointegrated.

CONCLUSION

These results suggest that polymorphism in the promoter region of MMP-8 gene is associated with early implant failure. This polymorphism can be a genetic marker to risk of implant loss.

CLINICAL RELEVANCE

The determination of this genetic pattern in osseointegration would enable the identification of individuals at higher risk to loss implant. Thus, genetic markers will be identified, contributing to an appropriate preoperative selection and preparation of strategies for prevention and therapy individualized to modulate the genetic markers and increase the success rate of treatments.

Evaluation of the influence of ozonotherapy on the clinical parameters and MMP levels in patients with chronic and aggressive periodontitis

PURPOSE

A comparison of the clinical status and salivary MMP levels after SRP alone or with ozonotherapy in patients with aggressive and chronic periodontitis.

MATERIAL/METHODS

The study was performed in 52 generally healthy subjects with chronic or aggressive periodontitis. Group CP-S consisted of 12 patients with chronic periodontitis, who underwent scaling and root planing (SRP). In group CP-O there were 25 patients with chronic periodontitis who additionaly to SRP underwent ozonotherapy. The same therapy was performed in group AP, containing 15 patients with aggressive periodontitis. Plaque index, approximal plaque index, bleeding on probing, sulcus bleeding index, probing pocket depth and clinical attachment loss were measured at baseline, at two weeks and two months post-therapy. The levels of MMP-1, MMP-8 and MMP-9 were estimated in non-stimulated saliva with an ELISA method.

RESULTS

All the clinical parameters assessed in the study groups were reduced after treatment. SRP with additional ozonotherapy provided an increase in MMP levels in patients with chronic periodontitis and a reduction in MMP levels in patients with aggressive periodontitis.

CONCLUSIONS

SRP followed by ozonotherapy does not lead to further improvement in clinical periodontal parameters in patients with AP and CP.

Matrix metalloproteinase-8 deficiency increases joint inflammation and bone erosion in the K/BxN serum-transfer arthritis model

Introduction

Rheumatoid arthritis is an autoimmune disease in which joint inflammation leads to progressive cartilage and bone erosion. Matrix metalloproteinases (MMPs) implicated in homeostasis of the extracellular matrix play a central role in cartilage degradation. However, the role of specific MMPs in arthritis pathogenesis is largely unknown. The aim of the present study was to investigate the role of Mmp-8 (collagenase-2) in an arthritis model.

Methods

Arthritis was induced in Mmp8-deficient and wildtype mice by K/BxN serum transfer. Arthritis severity was measured by a clinical index and ankle sections were scored for synovial inflammation, cartilage damage and bone erosion. cDNA microarray analysis, real-time PCR and western blot were performed to identify differential changes in gene expression between mice lacking Mmp8 and controls.

Results

Mmp8 deficiency increased the severity of arthritis, although the incidence of disease was similar in control and deficient mice. Increased clinical score was associated with exacerbated synovial inflammation and bone erosion. We also found that the absence of Mmp8 led to increased expression of IL-1β, pentraxin-3 (PTX3) and prokineticin receptor 2 (PROKR2) in arthritic mice joints.

Conclusions

Lack of Mmp-8 is accompanied by exacerbated synovial inflammation and bone erosion in the K/BxN serum-transfer arthritis model, indicating that this Mmp has a protective role in arthritis.

Inhibitors of collagenase but not of gelatinase reduce cartilage explant proteoglycan breakdown despite only low levels of matrix metalloproteinase activity

Aims-To investigate the level of matrix metalloproteinase activity during the time-course of cartilage explant proteoglycan breakdown; to determine the effects of selective small-molecule inhibitors of matrix metalloproteinases on proteoglycan degradation.Methods-The levels of matrix metalloproteinase activity in cartilage explant cultures and conditioned media were monitored by use of a quenched fluorescent substrate. The constants for inhibition of certain matrix metalloproteinases by a series of synthetic inhibitors were determined. Bovine and human cartilage explant cultures were treated with interleukin-1, tumor necrosis factor or retinoic acid and the amount of proteoglycan released into the culture medium in the absence and presence of the inhibitors was quantified. Control experiments, examining the inhibition of other proteinases, and investigating possible toxic or non-specific effects of the inhibitors, were carried out.Results-The profile of inhibition of proteoglycan release suggested the involvement of interstitial collagenase-like, rather than gelatinase- or possibly stromelysin-like, proteinases. No evidence was found for toxic or non-specific mechanisms of inhibition. Very low levels of activity of the known matrix metalloproteinases were present during the time-course of aggrecan breakdown.Conclusions-A novel collagenase-like proteinase(s) may be involved in cartilage proteoglycan breakdown. Gelatinase-type matrix metalloproteinases do not seem to be involved in this process. Specific collagenase inhibitors may be therapeutically efficacious in the treatment of arthritis.

MMP-8 promotes polymorphonuclear cell migration through collagen barriers in obliterative bronchiolitis

Increased levels of MMP-8 (neutrophil collagenase) have been reported in OB, but the biological role of MMP-8 in OB is not known. MMP-8 is an interstitial collagenase highly expressed by polymorphonuclear leukocytes, which are prominent in early OB. Here, we show that MMP-8 promotes migration of PMNs through the collagen-rich matrix in a mouse heterotopic airway transplant model of OB. Overall, MMP-8(-/-) mice had significantly fewer PMNs in the airway lumen 2 and 14 days post-transplantation, and the percentage of PMNs traversing the matrix to the lumen was decreased markedly in the MMP-8(-/-) compared with WT mice at 14 days. There were significantly more PMNs outside of the lumen in the ECM in the MMP-8(-/-) mice compared with WT mice. In vitro, significantly fewer MMP-8(-/-) PMNs migrated through 3D cross-linked collagen gels than WT PMNs. MMP inhibitor GM6001 was also able to impede migration of WT PMNs through collagen gels. The decreased migration was likely a result of pericollagenase activity of MMP-8, as WT PMNs expressing MMP-8 were not able to migrate effectively through collagen that was resistant to the collagenase. Protection from OB was seen in the MMP-8(-/-) mice, as the airway lumen had significantly less obliteration and collagen deposition, suggesting that MMP-8 plays an important role in the pathogenesis of OB.

Etiology and biomechanics of ankle arthritis

Of all joints in the body, the ankle joint is subjected to the highest forces per square centimeter and is injured more commonly. Yet, the incidence of symptomatic ankle arthritis is much lower than that of the knee and hip. Various mechanical, biochemical and anatomic peculiarities of the ankle account for its apparent resilience to the process of aging and trauma. The goal of this article is to help the reader better understand the functional paradoxes that make the ankle joint a unique and fascinating articulation.

Association of the 5A/6A promoter polymorphism of the MMP-3 gene with the radiographic progression of rheumatoid arthritis

Matrix metalloproteinases (MMPs) as a family of zinc-dependent endopeptidases have been involved in remodeling the extracellular matrix (ECM) in rheumatoid arthritis (RA). In RA patients synovial fluid and serum include enhanced levels of MMP-3. The 5A/6A polymorphism in the MMP-3 gene promoter can contribute to the severity of RA on account of a higher promoter activity of the 5A allele in vitro. The aim of the study was to associate the 5A/6A polymorphism of the MMP-3 gene with radiographic progression of RA. A total of 128 RA patients according to the ACR criteria were available for the study. Radiographs of both hands, obtained from all RA patients, were scored using the modified Sharp/van der Heijde method and the Steinbrocker method. The total Sharp score (TSS) and the annual radiographic progression rate (TSS/year) were calculated. Significant association with the 5A/6A polymorphism was found between patients with TSS/year <or= 1.00 and those with TSS/year > 1.00 in allelic frequencies (Pa = 0.046) and also in genotype distribution (Pg = 0.04). Compared to other genotypes the prevalence of 5A/5A genotype was lower within patients with TSS/year <or= 1.00 (odds ratio [OR] = 0.2; 95% confidence interval [CI] 0.04-0.85; P = 0.01). Also, in comparison to genotypes 5A/6A and 5A/5A, the prevalence of 6A/6A genotype was higher within patients with nonerosive RA (OR = 2.65; 95% CI 1.03-6.83, P = 0.02). Results obtained in this study provide the evidence of an association of the 5A/6A promoter polymorphism of the MMP-3 gene to the radiographic progression of RA.

Collagenase and surgical disease

Collagen types I, II, and III are the most abundant extracellular matrix (ECM) proteins. Collagenase is a member of the matrix metalloproteinase (MMP) family of enzymes, and is the principal enzyme involved with collagen degradation. Cellular-ECM interactions are vitally important to tissue structure and function. In this review, we summarize recent work that highlights the role of collagenase in ECM remodeling and repair, and further report that alterations of collagenase expression, function, and/or regulation are found in many diverse disease states, including aortic aneurysms, tumor invasiveness and their metastases, and hernias. Collagenase is intimately involved in many surgical diseases, and represents a potential target for therapy.

In situ localization of gelatinolytic activity during development and resorption of Meckel's cartilage in mice

Degradation of Meckel's cartilage in the middle portion is accompanied by hypertrophy and death of chondrocytes, calcification of the cartilaginous matrix, and chondroclastic resorption. We hypothesize that the gelatinolytic activity of matrix metalloproteinases (MMPs) largely contributes to the degradation of extracellular matrix (ECM) in the process. The activity in Meckel's cartilage of mouse mandibular arches at embryonic days 14-16 (E14-E16) was examined by a combination of in situ zymography (ISZ), using quenched fluorescent dye-labeled gelatin as a substrate, with CTT (a selective inhibitor of MMP-2 and -9) or with EDTA (a general MMP inhibitor). On E14 and E15, ISZ showed fluorescence in the perichondrium, in the intercellular septa between chondrocytes, and in the nucleus of chondrocytes. CTT attenuated fluorescence, and EDTA eliminated it. On E16, calcified cartilaginous matrix showed intense fluorescence, and dot-like fluorescence was observed in as-yet uncalcified intercellular septa, even after CTT treatment. EDTA inhibited fluorescence, but unexpectedly intense fluorescence was found in the cytoplasm of hypertrophic chondrocytes facing the resorption front. MMP-2, -9, and -13 immunoreactivity was detected in the perichondrium and chondrocytes of Meckel's cartilage. These findings suggest that MMPs and other proteinases capable of degrading gelatin play an integral role in the development, calcification, and resorption of Meckel's cartilage through ECM reconstitution.

Influence of early neutrophil depletion on MMPs/TIMP-1 balance in bleomycin-induced lung fibrosis

Pulmonary fibrosis is characterized by excessive deposition of extracellular matrix in interstitium resulting in respiratory failure associated with inflammation showing mainly neutrophil (PMN) recruitment. The turn over of extracellular matrix is partially regulated by proteases such as metalloproteinases (MMPs) and their inhibitors (TIMPs). We investigated the impact of PMN depletion on the MMP/TIMP-1 imbalance and the development of fibrosis in mice induced by bleomycin (0.3 mg/mouse). Administration of 200 microL of rabbit anti-mouse PMN antibody i.p. blunted the neutrophil influx detected in BAL and in whole blood one day after bleomycin administration. At day(14), hydroxyproline content was increased both in anti-PMN treated and control mice, without any difference between groups. At day one, bleomycin elicited a raise in pro-MMP-9 level in BAL that was significantly attenuated in anti-PMN depleted mice, whereas TIMP-1 and MMP-2 release were similar in both groups at day(1) and day(14). Higher RNA levels were observed in PMN-treated mice at day(1) for MMP-9 and MMP-2 and at day(14) for MMP-2 only. At day(14), bleomycin elicited a raise of TIMP-1 protein and RNA levels regardless of anti-PMN treatment, whereas MMP-9 returned to basal level. Bleomycin enhanced MMP-8 level in BAL at day(14) only for the control group. The amount of MMP-8 was more important in BAL from anti-PMN treated mice than in control mice at day(1) and day(14). PMN-depletion and the associated modifications in pro-MMP-9/TIMP-1 imbalance in lung during the early inflammatory phase do not alter susceptibility to bleomycin-induced pulmonary fibrosis.

Tetraspanin CD151 is expressed in osteoarthritic cartilage and is involved in pericellular activation of pro-matrix metalloproteinase 7 in osteoarthritic chondrocytes

OBJECTIVE

The proenzyme of matrix metalloproteinase 7 (proMMP-7), which can degrade various extracellular matrix (ECM) and non-ECM molecules after being activated, is overexpressed in osteoarthritic (OA) articular cartilage, but the process of its activation in the cartilage remains unknown. The present study was undertaken to investigate the expression of tetraspanin CD151 in OA cartilage and its involvement in proMMP-7 activation.

METHODS

The expression of CD151 in articular cartilage was examined by reverse transcription-polymerase chain reaction (RT-PCR), real-time PCR, immunohistochemistry, in situ hybridization, and immunoblotting. Chondrocytes were used to study the interaction between CD151 and proMMP-7, and activation of proMMP-7.

RESULTS

RT-PCR revealed expression of CD151 messenger RNA in all OA cartilage samples, but in only 30% of normal control cartilage samples. Immunohistochemistry and in situ hybridization findings indicated that CD151 was coexpressed with proMMP-7 in chondrocytes, mainly in the superficial and transitional zones of OA cartilage. CD151 immunoreactivity directly correlated with the Mankin score (r = 0.757, P < 0.0001 [n = 30]) and the degree of chondrocyte cloning (r = 0.83, P < 0.0001 [n = 30]) in the cartilage samples. Complexes CD151 and proMMP-7 and their colocalization on the cell membranes were demonstrated by immunoprecipitation and double fluorescence immunostaining of the OA chondrocytes. In situ zymography indicated that chondrocytes exhibit pericellular proteolytic activity, which was abolished by treatment with MMP inhibitors, anti-MMP-7 antibody, or anti-CD151 antibody.

CONCLUSION

These data demonstrate that CD151 is overexpressed in OA cartilage and suggest that CD151 plays a role in the pericellular activation of proMMP-7, leading to cartilage destruction and/or chondrocyte cloning.

Matrix metalloproteinase-8 (MMP-8) is the major collagenase in human dentin

OBJECTIVE

Previously an unidentified collagenolytic metalloprotease together with gelatinase (matrix metalloproteinase-2, MMP-2), and enamelysin (MMP-20) have been detected in human dentin. The aim of the study was to characterize dentinal collagenolytic enzymes. Furthermore, we hypothesized that the dentinal MMPs are protected by the mineral phase, and studied the stability of dentinal MMPs.

DESIGN

To characterize dentinal collagenolytic enzymes, we used Western blotting with specific antibodies against MMP collagenases (MMP-1, -8, and -13) and cathepsin K. MMP-8 immunofluorometric assay (IFMA) was also used for MMP-8 detection, and functional collagenase activity was examined with type I collagen degradation assay. The stability of dentinal MMPs was examined by autoclaving dentin blocks before protein extraction and subsequent examination of protein levels and the activities of dentin collagenase and gelatinases.

RESULTS

MMP-8 (collagenase-2) was detected in dentin both with Western blot and IFMA, and dentinal samples also cleaved the intact type I collagen into characteristic 3/4(alphaA)-cleavage products in vitro. No other collagenases or cathepsin K were detected. In autoclaved samples no MMP-8 was found, but gelatinase activity was observed in protein fractions of mineralized dentin.

CONCLUSIONS

MMP-8 represents the major collagenase in human dentin. Unlike MMP-8, dentinal gelatinases can be detected after autoclave treatment of dentin, indicating their high resistance to external sample treatment procedures.

Collagenolytic proteinases in keratoconus

PURPOSE

To study the proteolytic phenomena contributing to the pathogenesis of keratoconus, corneal enzymes with potential to cleave fibrillar collagen were studied.

METHODS

Immunohistochemical labeling was undertaken of conventional and novel mammalian collagenases (MMP-1, -2, -8, -13, and -14) of the matrix metalloproteinase (MMP) family and other collagenolytic proteinases of the serine (human trypsin-2) and cysteine (cathepsin K) endoproteinase families. The results were analyzed using a semiquantitative scoring system.

RESULTS

Labeling of MMP-8 was moderate in healthy controls, but weak in keratoconus. Moderate MMP-2 and weak MMP-14 expressions were similar in controls and keratoconus. MMP-1 was slightly overexpressed in keratoconus. In contrast, MMP-13 was weak in controls compared to moderate in keratoconus and human trypsin-2 and cathepsin K were moderate in controls and strong in keratoconus.

CONCLUSIONS

The collagenolytic milieu of human cornea is more complex than expected. Mesenchymal isoform of MMP-8 (ie, collagenase-2) participates in normal tissue remodeling, which may be impaired in keratoconus. MMP-2 (gelatinase A with interstitial collagenase activity) and MMP-14 (membrane-type MMP type I with collagenolytic potential) seem to be constitutively expressed and probably play a role in normal corneal remodeling. The most prominent changes in keratoconic cornea were observed in collagenase MMP-13 (ie, collagenase-3), and particularly, in cathepsin K and human trypsin-2, which were strongly expressed in keratoconus suggesting a role in intra- and extracellular pathological collagen destruction, respectively. This may contribute to stromal thinning characteristic for keratoconus.

Increased local matrix metalloproteinase-8 expression in the periodontal connective tissues of smokers with periodontal disease

Matrix metalloproteinase (MMP)-8 has been associated with the progression of periodontitis, a common inflammatory disease of the supporting structures of the teeth, and with other degradative diseases. Tobacco smokers are at high risk of developing periodontitis that may progress more rapidly and respond poorly to treatment. Therefore, MMP-8 expression was determined by immunofluorescence staining in 60 random, computer-selected fields in the excised periodontal tissues of smokers and non-smokers, balanced for age, gender, and periodontal status. Immunofluorescence intensity, representing MMP-8 expression, in the periodontal tissues of smokers (30 fields from 6 subjects, mean 1154+/-124 units) was significantly higher than that in the periodontal tissues of non-smokers (30 fields from 6 subjects, mean 817+/-60 units; p < 0.05). Serum MMP-8 concentrations were measured by ELISA and compared in a larger group of smokers (n = 20) and age- and gender-balanced non-smokers (n = 20). Systemic MMP-8 concentrations in smokers and non-smokers were not significantly different (p > 0.05). A local tobacco-related increase in MMP-8 burden may contribute to periodontal disease progression in tobacco smokers. This finding may also have relevance to other tobacco-induced inflammatory diseases, such as vascular and pulmonary diseases.

Vaginal matrix metalloproteinase levels in pregnant women with bacterial vaginosis

OBJECTIVE

To compare matrix metalloproteinase (MMP)-8 and MMP-9 levels in the vaginal secretions of pregnant women with or without asymptomatic bacterial vaginosis (BV).

METHODS

In this study, vaginal levels and molecular forms of MMP-8 and MMP-9 were studied in 36 pregnant women between 28 and 34 weeks of gestation with asymptomatic BV and 41 pregnant women, matched for gestational age, without BV.

RESULTS

Vaginal MMP-8 concentrations were significantly higher (P = .023) in BV-positive women. There was no significant difference in MMP-9 levels between healthy pregnant controls and BV-positive pregnant women. The presence of MMP-8 was confirmed by a 38-kd band on Western blots.

CONCLUSIONS

Our findings show that BV is associated with increased levels of MMP-8 in vaginal fluid. Increased production of collagen-degrading enzymes such as MMP-8 is a possible cause of spontaneous preterm delivery in pregnant women with asymptomatic BV.

Matrix metalloproteases from chondrocytes generate an antiangiogenic 16 kDa prolactin

The 16 kDa N-terminal fragment of prolactin (16K-prolactin) is a potent antiangiogenic factor. Here, we demonstrate that matrix metalloproteases (MMPs) produced and secreted by chondrocytes generate biologically functional 16K-prolactin from full-length prolactin. When incubated with human prolactin at neutral pH, chondrocyte extracts and conditioned medium, as well as chondrocytes in culture, cleaved the Ser155-Leu156 peptide bond in prolactin, yielding - upon reduction of intramolecular disulfide bonds - a 16 kDa N-terminal fragment. This 16K-prolactin inhibited basic fibroblast growth factor (FGF)-induced endothelial cell proliferation in vitro. The Ser155-Leu156 site is highly conserved, and both human and rat prolactin were cleaved at this site by chondrocytes from either species. Conversion of prolactin to 16K-prolactin by chondrocyte lysates was completely abolished by the MMP inhibitors EDTA, GM6001 or 1,10-phenanthroline. Purified MMP-1, MMP-2, MMP-3, MMP-8, MMP-9 and MMP-13 cleaved human prolactin at Gln157, one residue downstream from the chondrocyte protease cleavage site, with the following relative potency: MMP-8&gt;MMP-13 &gt;MMP-3&gt;MMP-1=MMP-2&gt;MMP-9. Finally, chondrocytes expressed prolactin mRNA (as revealed by RT-PCR) and they contained and released antiangiogenic N-terminal 16 kDa prolactin (detected by western blot and endothelial cell proliferation). These results suggest that several matrix metalloproteases in cartilage generate antiangiogenic 16K-prolactin from systemically derived or locally produced prolactin.

Collagen degradation by interleukin-1beta-stimulated gingival fibroblasts is accompanied by release and activation of multiple matrix metalloproteinases and cysteine proteinases

OBJECTIVE

Several collagenolytic matrix metalloproteinases (MMPs) have recently been identified in gingival fibroblasts, while secreted cysteine proteinases could also participate in connective tissue destruction in periodontitis. To clarify their involvement, we examined enzyme release during collagen breakdown by cultured cytokine-stimulated fibroblasts.

MATERIALS AND METHODS

Gingival fibroblasts were derived from four chronic periodontitis patients and cultured on collagen gels in serum-free medium for 1-4 days. Collagenolysis was measured by hydroxyproline release into the medium. Proteinases were assessed by electrophoresis and immunoblotting.

RESULTS

Adding interleukin-1beta resulted in progressive gel breakdown. This was associated particularly with a shift in MMP-1 band position from proenzyme to active enzyme and the appearance of active as well as proenzyme forms of cathepsin B. There was also partial processing of pro-MMP-13 and increased immunoreactivity for active cathepsin L. In addition, both pro-forms and active forms of MMP-8, membrane-type-1-MMP and MMP-2 were present in control and treated cultures.

CONCLUSIONS

Fibroblast MMP-1 was most likely responsible for collagen dissolution in the culture model, while cathepsin B may have been part of an activation pathway. All studied proteinases contribute to extracellular matrix destruction in inflamed gingival tissue, where they probably activate each other in proteolytic cascades.

Matrix Metalloproteinase-8 and -9 Are Increased at the Site of Abdominal Aortic Aneurysm Rupture

Background— Abdominal aortic aneurysm (AAA) expansion is characterized by extracellular matrix degradation and widespread inflammation. In contrast, the processes that characterize AAA rupture are not well understood. The aim of this study was to investigate the proteolytic and cellular activity of ruptured AAA, focusing on matrix metalloproteinases (MMPs) and their inhibitors (TIMPs).

Methods and Results— Anterior aneurysm wall biopsies were taken from 55 nonruptured and 21 ruptured AAAs. A further biopsy from the site of rupture was taken from 12 of the ruptured AAAs. MMP-1, -2, -3, -8, -9, and -13, as well as TIMP-1 and -2, were quantified in each biopsy with ELISA. A comparison of anterior aneurysm biopsies showed no difference in MMP or TIMP concentrations between nonruptured and ruptured AAA. In a comparison of ruptured AAA biopsies, MMP-8 and -9 levels were significantly elevated in the 12 rupture site biopsies compared with their 12 paired anterior wall biopsies, whereas other MMPs and TIMPs showed no difference (MMP-8, P <0.001; MMP-9, P =0.01). MMP-8 and -9 expression was mediated by native mesenchymal cells and was independent of the inflammatory infiltrate.

Conclusions— A localized increase in MMP-8 and –9, mediated by native mesenchymal cells, presents a potential pathway for collagen breakdown and AAA rupture.

Matrix metalloproteinases: contribution to pathogenesis, diagnosis and treatment of periodontal inflammation

Matrix metalloproteinases (MMPs) form a family of enzymes that mediate multiple functions both in the tissue destruction and immune responses related to periodontal inflammation. The expression and activity of MMPs in non-inflamed periodontium is low but is drastically enhanced to pathologically elevated levels due to the dental plaque and infection-induced periodontal inflammation. Soft and hard tissue destruction during periodontitis and peri-implantitis are thought to reflect a cascade of events involving bacterial virulence factors/enzymes, pro-inflammatory cytokines, reactive oxygen species and MMPs. However, recent studies suggest that MMPs can also exert anti-inflammatory effects in defence of the host by processing anti-inflammatory cytokines and chemokines, as well as by regulating apoptotic and immune responses. MMP-inhibitor (MMPI)-drugs, such as doxycycline, can be used as adjunctive medication to augment both the scaling and root planing-treatment of periodontitis locally and to reduce inflammation systematically. Furthermore, MMPs present in oral fluids (gingival crevicular fluid (GCF), peri-implant sulcular fluid (PISF), mouth-rinses and saliva) can be utilized to develop new non-invasive, chair/bed-side, point-of-care diagnostics for periodontitis and dental peri-implantitis.

Collagen degradation products modulate matrix metalloproteinase expression in cultured articular chondrocytes

Destruction of collagen within osteoarthritic cartilage depends in part on collagen-degrading matrix metalloproteases (MMP). Degradative fragments of type II collagen (Col II) occur in normal and in osteoarthritic cartilage, and may contribute to regulation of matrix turnover by interfering with normal cell-matrix communication pathways. Therefore, the effects of different types of collagen fragments on mRNA and protein levels of MMP-2, MMP-3, MMP-9, and MMP-13 in cultured bovine articular knee chondrocytes and explants were examined. Primary chondrocytes and explants were incubated with fragments from whole cartilage collagen matrix (Colf) and from purified type II collagen (Col2f), or with a synthetic 29-mer peptide representing the amino-terminal domain of type II collagen (Ntelo). Gelatin zymography revealed increases of proMMP-2, a shift towards active MMP-2 and increases in proMMP-9, depending on the type of fragment. In situ hybridization of cartilage sections displayed MMP-3 mRNA in virtually all cells. Moderate to strong increases in MMP-2, MMP-3, MMP-9, and MMP-13 mRNA levels were detected by quantitative PCR. The results demonstrate stimulating effects of collagen fragments on both mRNA and/or protein from MMP -2, -3, -9, and -13, and suggest a novel mechanism of MMP induction and activation that includes a particular role for N-telo in controlling catabolic pathways of matrix turnover.

Serum matrix metalloproteinases and tissue inhibitors of metalloproteinases in ankylosing spondylitis: MMP-3 is a reproducibly sensitive and specific biomarker of disease activity

OBJECTIVE

To submit serum levels of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) to statistical analyses to test their exact degrees of clinical usefulness as biomarkers for detecting high disease activity in ankylosing spondylitis (AS), comparing them with erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).

METHODS

Serum levels of MMP-1, -3, -9 and TIMP-1 and -2 were measured in 42 AS patients and 20 healthy controls. The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) provided the gold standard for measuring disease activity. Patients with BASDAI > or =4 were regarded as having high disease activity. The results were compared with results for a separate cohort of 41 AS patients.

RESULTS

Only MMP-3 levels were significantly higher in AS patients than in healthy controls (P<0.001). Within AS patients, MMP-3 levels were also higher in patients with high disease activity compared with those with low disease activity, and correlated significantly with BASDAI (r = 0.366, P = 0.017) and functional indices (r = 0.344, P = 0.026). The correlation with BASDAI was stable in a 1-yr follow-up (r = 0.464, P = 0.095) and reproducible with two different enzyme-linked immunosorbent assays. For detecting high disease activity, the sensitivity and specificity of MMP-3 level was 69.2 and 68.8% respectively. Most importantly, using receiver operating characteristic plots to analyse the two cohorts, MMP-3 was more accurate than ESR and CRP in detecting AS patients with high disease activity (P = 0.01 and P = 0.009, respectively).

CONCLUSION

Using several analytical approaches that have never been reported previously, we showed that MMP-3 is a more useful biomarker than ESR and CRP to detect high disease activity in AS.

A Review of Biological Factors Implicated in Abdominal Aortic Aneurysm Rupture

Abdominal aortic aneurysm (AAA) rupture is the 13th commonest cause of death in the Western World. Although considerable research has been applied to the aetiology and mechanism of aneurysm expansion, little is known about the mechanism of rupture. Aneurysm rupture was historically considered to be a simple physical process that occurred when the aortic wall could no longer contain the haemodynamic stress of the circulation. However, AAAs do not conform to the law of Laplace and there is growing evidence that aneurysm rupture involves a complex series of biological changes in the aortic wall. This paper reviews the available data on patient variables associated with aneurysm rupture and presents the evidence implicating biological factors in AAA rupture.

Collagenases in cancer

Three mammalian collagenases (MMP-1, MMP-8, and MMP-13) belong to family of matrix metalloproteinases and are the principal secreted endopeptidases capable of cleaving collagenous extracellular matrix. In addition to fibrillar collagens, collagenases can cleave several other matrix and non-matrix proteins including growth factors, and this way regulate cell growth and survival. Collagenases are important proteolytic tools for extracellular matrix remodeling during organ development and tissue regeneration, but they also apparently play important roles in many pathological situations and tumor progression and metastasis. Because of their potentially destructive characteristics the expression and activity of collagenases are strictly controlled. Synthesis of collagenases is regulated by extracellular signals via cellular signal transduction pathways at transcriptional and post-transcriptional level. Collagenases are synthesized as inactive pro-forms, and once activated, their activity is inhibited by specific tissue inhibitors of metalloproteinases, TIMPs, as well as by non-specific proteinase inhibitors. In this review we discuss the current view on the role of collagenases in tumor growth, invasion, and metastasis, as a basis for their feasibility in diagnosis and prognostication, as well as therapeutic targets in cancer patients.

Cartilage breakdown in rheumatoid arthritis

Rheumatoid arthritis (RA) is a connective tissue disease characterized by destruction of the joint cartilage and subsequently of the underlying bone. Cartilage destruction is due to proteolysis by enzymes called metalloproteinases (MMPs), whose production and expression are regulated by numerous local mediators such as cytokines, growth factors, prostaglandins, oxygen species, and neuropeptides. MMP activation is largely due to a stimulatory effect of cytokines including IL-1beta and TNFalpha. When these cytokines bind to their membrane receptor, they set off signaling cascades, with activation of TGFbeta-activating kinase (TAK-1), of NF-kappaB by Ikappa-B kinase, of mitogen-activated protein kinases (MAP kinases), and finally of activator protein-1 (AP-1). Tissue inhibitors of MMPs (TIMPs) specifically inhibit MMPs. The interrelations between joint inflammation and joint destruction remain poorly understood. Experimental data suggest that IL-1 may be involved chiefly in joint destruction and TNF in joint inflammation. However, TNF antagonists are potent inhibitors of joint destruction in clinical practice. These results suggest that the mediators function as a network and that inhibition of a single mediator can affect the entire web. Insights gained into the innermost mechanisms of cartilage breakdown in patients with RA have led to major therapeutic breakthroughs. Thus, TNF antagonists have proved highly effective in RA. Future progress will no doubt stem from new knowledge about the extracellular mediators and intracellular signaling pathways that lead to the production and activation of enzymes responsible for cartilage degradation.

MMP-3 and -8 expression is found in the condylar surface of temporomandibular joints with internal derangement

BACKGROUND

Internal derangement is one of the most common disorder of the temporomandibular joint (TMJ). The aim of this study was to investigate the associations of matrix metalloproteinase (MMP)-3 and -8 expression in articular condylar surface with different stages of TMJ internal derangement according to Wilkes (Minn Med, 1978; 61: 645-52) and osteoarthrosis (OA) according to Dijkgraaf et al. (J Oral Maxillofac Surg, 1995; 53: 1182-92).

METHODS

The study was based on 54 condylar specimens obtained during TMJ surgery. Immunohistochemistry using antibodies specific to MMP-3 and -8, represented in cartilage destruction, was carried out.

RESULTS

In all tissue specimens, MMP-3 expression was intense in the surface layer but showed less intensive staining in the deeper layers. Some MMP-8 expression was also seen. The severity of TMJ internal derangement, however, did not seem to have a statistically significant correlation (P<0.05) with the expression of these enzymes.

CONCLUSION

The study confirms that distinct expression of MMP-3 and -8 is found in the condylar surface of TMJs with internal derangement.

Matrix metalloproteinases and their clinical applications in orthopaedics

Imbalance in the expression of matrix metalloproteinases and their inhibitors contribute considerably to abnormal connective tissue degradation prevalent in various orthopaedic joint diseases such as rheumatoid arthritis and osteoarthritis. Matrix metalloproteinase expression has been detected in ligament, tendon, and cartilage tissues in the joint. They are known to contribute to the development, remodeling, and maintenance of healthy tissue through their ability to cleave a wide range of extracellular matrix substrates. Their role has been extended to cell growth, migration, differentiation, and apoptosis. In orthopaedics, their clinical applications constantly are being explored. The multiple steps in matrix metalloproteinase regulation offer potential targets for inhibition, useful in drug therapy. The correlation between matrix metalloproteinases and progression in joint erosion presents potential prognostic and diagnostic tools in rheumatoid arthritis. Matrix metalloproteinases also can be incorporated into scaffold design to control the degradation rate of engineered tissue constructs. This current review aims to summarize and emphasize the importance of matrix metalloproteinases and their natural inhibitors in the maturation of musculoskeletal tissue through matrix remodeling and, therefore, in the generation of a new clinical potential in orthopaedics.

Functionally significant SNP MMP8 promoter haplotypes and preterm premature rupture of membranes (PPROM)

Matrix metalloproteinase 8 (MMP8), an enzyme that degrades fibrillar collagens imparting strength to the fetal membranes, is expressed by leukocytes and chorionic cytotrophoblast cells. We identified three single nucleotide polymorphisms (SNPs) at -799C/T, -381A/G and +17C/G from the major transcription start site in the MMP8 gene, and determined the functional significance of these SNPs by analyzing their impact upon MMP8 promoter activity and their association with preterm premature rupture of membranes (PPROM). The minor alleles +17 (G) and -381 (G) were in complete linkage disequilibrium. A promoter fragment containing the three minor alleles had 3-fold greater activity in chorion-like trophoblast cells (BeWo, JEG-3 and HTR-8/SVneo) compared with the major allele promoter construct. Electrophoretic mobility shift assays revealed differences in BeWo nuclear protein binding to oligonucleotides representing the -381 and -799 SNPs, suggesting that the minor alleles have reduced transcription factor binding. A case-control study of African-American neonates using allele-specific primers revealed a statistically significant association between the three minor allele haplotype, which displays the highest MMP8 promoter activity in trophoblast cells, with PPROM with an odds ratio (OR) of 4.63 (P < 0.0001), whereas the major allele promoter appeared to be protective (OR = 0.52, P < 0.0002). None of the minor alleles were individually associated with PPROM. These findings demonstrate the functional significance of SNP haplotypes in the MMP8 gene and associations with obstetrical outcomes.

TGF-beta1 stimulates production of gelatinase (MMP-9), collagenases (MMP-1, -13) and stromelysins (MMP-3, -10, -11) by human corneal epithelial cells

Matrix metalloproteinases (MMPs) have been implicated in the pathogenesis of ocular surface diseases. This study investigated the regulated expression of gelatinases (MMP-2 and -9), collagenases (MMP-1 and -13) and stromelysins (MMP-3, -10, and -11) by TGF-beta1 in cultured human corneal epithelial cells. Primary human corneal epithelial cell cultures were grown to confluence and treated with different concentrations (0.1, 1.0, 10 ng ml(-1)) of TGF-beta1 in serum-free medium for 6-24 hr. Total RNA was isolated from cultured cells with or without TGF-beta1 treatment for 6 hr and subjected to semi-quantitative RT-PCR and Northern hybridization. Conditioned media were collected from cultures with or without TGF-beta1 treatment for 24 hr to evaluate the MMP production by ELISA and activity assays. Semi-quantitative RT-PCR revealed that the expressions of MMP-9, -1, -13, -3, -10 and -11 mRNA were up-regulated by TGF-beta1 in a concentration-dependent fashion, while MMP-2 and MMP-14 production did not change. Northern hybridization confirmed these findings. Gelatin zymography, MMP ELISA and activity assays showed concentration-dependent stimulated production and activity of MMP-9, -1, -13, -3 and -10 protein in the conditioned media of cultures treated for 24 hr with TGF-beta1. In conclusion, our results demonstrate that TGF-beta1 stimulates the expression and production of gelatinase (MMP-9), collagenases (MMP-1, -13) and stromelysins (MMP-3, -10, -11) in human corneal epithelial cells. These findings suggest that TGF-beta1 may play a role in the pathogenesis of MMP mediated ocular surface diseases, such as sterile corneal ulceration.

Membrane-bound matrix metalloproteinase-8 on activated polymorphonuclear cells is a potent, tissue inhibitor of metalloproteinase-resistant collagenase and serpinase

Little is known about the cell biology or the biologic roles of polymorphonuclear cell (PMN)-derived matrix metalloproteinase-8 (MMP-8). When activated with proinflammatory mediators, human PMN release only approximately 15-20% of their content of MMP-8 ( approximately 60 ng/10(6) cells) exclusively as latent pro-MMP-8. However, activated PMN incubated on type I collagen are associated with pericellular collagenase activity even when bathed in serum. PMN pericellular collagenase activity is attributable to membrane-bound MMP-8 because: 1) MMP-8 is expressed in an inducible manner in both pro- and active forms on the surface of human PMN; 2) studies of activated PMN from mice genetically deficient in MMP-8 (MMP-8(-/-)) vs wild-type (WT) mice show that membrane-bound MMP-8 accounts for 92% of the MMP-mediated, PMN surface type I collagenase activity; and 3) human membrane-bound MMP-8 on PMN cleaves types I and II collagens, and alpha(1)-proteinase inhibitor, but is substantially resistant to inhibition by tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2. Binding of MMP-8 to the PMN surface promotes its stability because soluble MMP-8 has t(1/2) = 7.5 h at 37 degrees C, but membrane-bound MMP-8 retains >80% of its activity after incubation at 37 degrees C for 18 h. Studies of MMP-8(-/-) vs WT mice given intratracheal LPS demonstrate that 24 h after intratracheal LPS, MMP-8(-/-) mice have 2-fold greater accumulation of PMN in the alveolar space than WT mice. Thus, MMP-8 has an unexpected, anti-inflammatory role during acute lung injury in mice. TIMP-resistant, active MMP-8 expressed on the surface of activated PMN is likely to be an important form of MMP-8, regulating lung inflammation and collagen turnover in vivo.