Matrix-degrading metalloproteinases and their roles in joint destruction

Infrared Spectroscopy Can Differentiate Between Cartilage Injury Models: Implication for Assessment of Cartilage Integrity

In order to improve the ability of clinical diagnosis to differentiate articular cartilage (AC) injury of different origins, this study explores the sensitivity of mid-infrared (MIR) spectroscopy for detecting structural, compositional, and functional changes in AC resulting from two injury types. Three grooves (two in parallel in the palmar-dorsal direction and one in the mediolateral direction) were made via arthrotomy in the AC of the radial facet of the third carpal bone (middle carpal joint) and of the intermediate carpal bone (the radiocarpal joint) of nine healthy adult female Shetland ponies (age = 6.8 ± 2.6 years; range 4-13 years) using blunt and sharp tools. The defects were randomly assigned to each of the two joints. Ponies underwent a 3-week box rest followed by 8 weeks of treadmill training and 26 weeks of free pasture exercise before being euthanized for osteochondral sample collection. The osteochondral samples underwent biomechanical indentation testing, followed by MIR spectroscopic assessment. Digital densitometry was conducted afterward to estimate the tissue's proteoglycan (PG) content. Subsequently, machine learning models were developed to classify the samples to estimate their biomechanical properties and PG content based on the MIR spectra according to injury type. Results show that MIR is able to discriminate healthy from injured AC (91%) and between injury types (88%). The method can also estimate AC properties with relatively low error (thickness = 12.7% mm, equilibrium modulus = 10.7% MPa, instantaneous modulus = 11.8% MPa). These findings demonstrate the potential of MIR spectroscopy as a tool for assessment of AC integrity changes that result from injury.

Cartilage-Related Collagens in Osteoarthritis and Rheumatoid Arthritis: From Pathogenesis to Therapeutics

Collagens serve essential mechanical functions throughout the body, particularly in the connective tissues. In articular cartilage, collagens provide most of the biomechanical properties of the extracellular matrix essential for its function. Collagen plays a very important role in maintaining the mechanical properties of articular cartilage and the stability of the ECM. Noteworthily, many pathogenic factors in the course of osteoarthritis and rheumatoid arthritis, such as mechanical injury, inflammation, and senescence, are involved in the irreversible degradation of collagen, leading to the progressive destruction of cartilage. The degradation of collagen can generate new biochemical markers with the ability to monitor disease progression and facilitate drug development. In addition, collagen can also be used as a biomaterial with excellent properties such as low immunogenicity, biodegradability, biocompatibility, and hydrophilicity. This review not only provides a systematic description of collagen and analyzes the structural characteristics of articular cartilage and the mechanisms of cartilage damage in disease states but also provides a detailed characterization of the biomarkers of collagen production and the role of collagen in cartilage repair, providing ideas and techniques for clinical diagnosis and treatment.

Adenosine inhibits TNFα-induced MMP-3 production in MH7A rheumatoid arthritis synoviocytes via A2A receptor signaling

Adenosine causes the anti-inflammatory effect of MTX; however, the contributions of synoviocyte adenosine receptors (AdoRs) are unknown, and matrix metalloproteinase 3 (MMP-3) is released by fibroblast-like synoviocytes in response to inflammatory signaling. To understand the mechanism of the clinical observation that the matrix proteinase-3 concentration of patients with rheumatoid arthritis treated successfully with methotrexate does not usually normalize, we investigated the effects of A_2A AdoR activation and inhibition on tumor necrosis factor-alpha (TNFα)-induced MMP-3 release by MH7A human rheumatoid synovial cells. MH7A cells constitutively expressed membrane-associated A_2A AdoRs, and HENECA enhanced intracellular cAMP. Stimulation with TNFα markedly enhanced release of MMP-3 from MH7A cells, whereas HENECA partially and dose-dependently inhibited TNFα-evoked MMP-3 release. Similarly, dbcAMP partially inhibited TNFα-induced MMP-3 release. Pretreatment with ZM241385 reversed the inhibitory effects of HENECA. Further, TNFα induced p38 MAPK and ATF-2 phosphorylation, whereas HENECA suppressed p38 MAPK and ATF-2 phosphorylation. We concluded that adenosine signaling via A_2A AdoRs, adenylyl cyclase, and cAMP reduces TNFα-induced MMP-3 production by interfering with p38 MAPK/ATF-2 activity. Activation of A_2A AdoR signaling alone using HENECA did not reduce TNFα-induced MMP-3 production to the basal levels, which may explain why MTX usually decreases but does not eliminate serum MMP-3.

The collagenases: are they tractable targets for preventing cartilage destruction in osteoarthritis?

INTRODUCTION

The etiology and pathogenesis of osteoarthritis (OA) have been intensely investigated; however, the disease course and progression are not completely understood. A prominent role for interstitial collagenases is recognized in this degenerative process, hence strategies to target them are of major interest.

AREAS COVERED

The pathogenesis of OA, the role of interstitial collagenases (MMP-1, -8 and -13) and collagenase modifying drugs are examined and discussed. We reviewed relevant papers from PubMed and Google Scholar.

EXPERT OPINION

There is strong evidence for the therapeutic potential of MMP inhibitors in OA; however, they are not expected to impact the inflammatory process. Therefore, there is a need for a relative inhibitor of MMP-13 collagenase which possesses anti-inflammatory properties. The identification of novel broad-spectrum relative multiple peptidase inhibitors could provide desirable tools for the prophylaxis, cure, or treatment of diseases involving articular cartilage (AC) degradation, in particular OA.

Meroterpenoid-Rich Fraction of the Ethanol Extract of Sargassum Serratifolium Suppresses Collagen-Induced Rheumatoid Arthritis in DBA/1J Mice Via Inhibition of Nuclear Factor κB Activation

SCOPE

Rheumatoid arthritis (RA) is an autoimmune disorder related to the inflammation of cartilage due to the infiltration of inflammatory cells. Sargassum serratifolium, a brown alga, possesses strong anti-inflammatory activities.

METHODS AND RESULTS

The effect of meroterpenoid-rich fraction from the ethanol extract of S. serratifolium (MES) on RA and its underlying mechanisms on the inhibition of RA using a collagen-induced arthritis (CIA) mouse model are examined. The results show that MES ameliorates paw swelling and reduces the arthritis score. MES considerably decreases the secretion of pro-inflammatory cytokines in the serum and joint tissue of mice. Histopathological analysis demonstrates that MES strongly inhibited bone damage and inflammatory cell intrusion in the joint tissue. The expression of inflammatory enzymes and adhesion molecules is significantly inhibited in the serum and joint tissue of MES-fed mice. In addition, MES downregulates the nuclear factor κB (NF-κB) signaling pathway by suppressing the phosphorylation of protein kinase B, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinases.

CONCLUSIONS

MES supplementation remarkably reduces inflammatory response in CIA mouse model. These results indicate that MES can be used as a pharmaceutical agent against RA.

Effect of Kaempferia parviflora extract on knee osteoarthritis

Knee osteoarthritis (OA) is becoming more prevalent worldwide due to increases in the numbers of elderly and obese patients. Currently, pharmaceutical medicines used for the treatment of OA are for symptomatic therapy and therefore new therapeutic agents are needed. Kaempferia parviflora (KP) is a plant growing naturally in Southeast Asia and has various pharmacological effects including an anti-inflammatory effect, but no effect on OA has yet been reported. We therefore conducted a search for the effects KP and the active components of KP extract (KPE) exert on OA as well as its mechanism of action. Results from a study of KPE using the monoiodoacetic acid rat OA model revealed that KPE reduced the pain threshold and severity of osteoarthritic cartilage lesions. The mechanism of action and active components were then investigated using IL-1β-treated human knee-derived chondrocytes. KPE, as well as 5,7-dimethoxyflavone and 5,7,4'-trimethoxyflavone, which are key constituents of KPE and highly absorbable into the body, reduced the expression of matrix metalloproteinases (MMPs), which are the main extracellular matrix enzymes that degrade collagen within cartilage. As mentioned above, KPE acted to suppress OA and 5,7-dimethoxyflavone and 5,7,4'-trimethoxyflavone were shown to be involved as part of KPE's mechanism that inhibits MMPs.

Mori Folium water extract alleviates articular cartilage damages and inflammatory responses in monosodium iodoacetate‑induced osteoarthritis rats

Mori folium, the leaf of Morus alba L. (Moraceae), has been widely used in traditional medicine for the treatment of various diseases. It has been recently reported that Mori folium possesses potential chondroprotective effects in interleukin (IL)-1β-stimulated human chondrocytes; however, its protective and therapeutic potential against osteoarthritis (OA) in an animal model remains unclear. In this study, as part of an ongoing screening program to evaluate the anti-osteoarthritic potential of Mori folium, the protective effects of a water extract of Mori folium (MF) on cartilage degradation and inflammatory responses in a monosodium iodoacetate (MIA)-induced OA rat model were evaluated. The results demonstrated that administration of MF had a tendency to attenuate the damage to articular cartilage induced by MIA, as determined by knee joint swelling and the histological grade of OA. The elevated levels of matrix metalloproteinases-13 and two bio-markers for the diagnosis and progression of OA, such as the cartilage oligomeric matrix protein and C-telopeptide of type II collagen, were markedly ameliorated by MF administration in MIA-induced OA rats. In addition, MF significantly suppressed the production of pro-inflammatory cytokines, including IL-1β, IL-6 and tumor necrosis factor-α. MF also effectively inhibited the expression of inducible nitric oxide (NO) synthase and cyclooxygenase-2, thus inhibiting the release of NO and prostaglandin E₂. Although further work is required to fully understand the critical role and clinical usefulness, these findings indicate that MF may be a potential therapeutic option for the treatment of OA.

The Role of Matrix Metalloproteinase Polymorphisms in Ischemic Stroke

Stroke remains the fifth leading cause of mortality in the United States with an annual rate of over 128,000 deaths per year. Differences in incidence, pathogenesis, and clinical outcome have long been noted when comparing ischemic stroke among different ethnicities. The observation that racial disparities exist in clinical outcomes after stroke has resulted in genetic studies focusing on specific polymorphisms. Some studies have focused on matrix metalloproteinases (MMPs). MMPs are a ubiquitous group of proteins with extensive roles that include extracellular matrix remodeling and blood-brain barrier disruption. MMPs play an important role in ischemic stroke pathophysiology and clinical outcome. This review will evaluate the evidence for associations between polymorphisms in MMP-1, 2, 3, 9, and 12 with ischemic stroke incidence, pathophysiology, and clinical outcome. The role of polymorphisms in MMP genes may influence the presentation of ischemic stroke and be influenced by racial and ethnic background. However, contradictory evidence for the role of MMP polymorphisms does exist in the literature, and further studies will be necessary to consolidate our understanding of these multi-faceted proteins.

Clinically relevant radiographic progression in joint destruction in RA patients with abnormal MMP-3 or high levels of CRP despite 1-year treatment with infliximab

OBJECTIVE

Identify the independently related factors of joint destruction progression in RA patients despite of infliximab treatment.

METHODS

The subjects were cases who underwent infliximab treatment for one year or longer in our department (n = 244). Patients in which modified total sharp score (mTSS), joint erosion (JE), and joint space narrowing (JSN) had advanced to the standard value (3.0) or more for one year were defined as mTSS- Clinically-Relevant-Rapid Progression (CRRP) (n = 20), JE-CRRP (n = 20), and JSN-CRRP (n = 23), and the respective related factors at baseline and week 54 were defined by multiple logistic regression.

RESULTS

The median disease duration was 24 months and median mTSS 9.0 at baseline. The median DAS28, CRP, and yearly progression of mTSS improved from 5.8 to 2.6, 1.2 to 0.1 mg/dL, and 4.4 to 0.0 point/year, respectively. The related factor in each of mTSS-CRRP, JE-CRRP, and JSN-CRRP was high CRP levels at baseline. At week 54, the related factor of mTSS-CRRP and JSN-CRRP was high MMP-3 titer; however, the related factor of JE-CRRP was high CRP levels.

CONCLUSION

High CRP levels at baseline were an independent predictive factor of joint destruction advancement during infliximab treatment. Moreover, it was believed that abnormal MMP-3 at week 54 was the index for mTSS and JSN advancement, while high CRP levels were the index for JE advancement.

Observing the development of the temporomandibular joint in embryonic and post-natal mice using various staining methods

The temporomandibular joint (TMJ) is a specialized synovial joint that is essential for the movement and function of the mammalian jaw. The TMJ develops from two mesenchymal condensations, and is composed of the glenoid fossa that originates from the otic capsule by intramembranous ossification, the mandibular condyle of the temporal bone and a fibrocartilagenous articular disc derived from a secondary cartilaginous joint by endochondral ossification. However, the development of the TMJ remains unclear. In the present study, the formation and development of the mouse TMJ was investigated between embryonic day 13.5 and post-natal day 180 in order to elucidate the morphological and molecular alterations that occur during this period. TMJ formation appeared to proceed in three stages: Initiation or blastema stage; growth and cavitation stage; and the maturation or completion stage. In order to investigate the activity of certain transcription factors on TMJ formation and development, the expression of extracellular matrix (ECM), sex determining region Y-box 9, runt-related transcription factor 2, Indian hedgehog homolog, Osterix, collagen I, collagen II, aggrecan, total matrix metalloproteinase (MMP), MMP-9 and MMP-13 were detected in the TMJ using in situ and/or immunohistochemistry. The results indicate that the transcription factors, ECM and MMP serve critical functions in the formation and development of the mouse TMJ. In summary, the development of the mouse TMJ was investigated, and the molecular regulation of mouse TMJ formation was partially characterized. The results of the present study may aid the systematic understanding of the physiological processes underlying TMJ formation and development in mice.

Regulation of serum matrix metalloproteinases and tissue inhibitor of metalloproteinases-1 following rituximab therapy in patients with rheumatoid arthritis refractory to anti-tumor necrosis factor blockers

In our article, we evaluated the regulatory effects of the infusions of rituximab, a monoclonal antibody directed against CD20⁺ B cells, on the serum matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases-1 (TIMP-1) levels in patients with active rheumatoid arthritis (RA) not responding to anti-tumor necrosis factor (anti-TNF) therapy. Twelve RA patients were planned to receive four infusions of 1,000 mg of rituximab at weeks 0, 2, 24 and 26. The therapy was combined with methotrexate (MTX) (20–30 mg/week). Seven patients were refractory to previously received infliximab, and five to etanercept. Serum concentrations of interstitial collagenase (MMP-1), stromelysin-1 (MMP-3), gelatinase B (MMP-9) and TIMP-1 were measured by ELISA on weeks 0, 2, 12, 24, 36 and 52. Initial infusion of rituximab downregulated serum MMP-1 (p < 0.01), MMP-3 (p < 0.001), MMP-9 (p < 0.001) and TIMP-1 (p < 0.05) levels. Second drug administration caused even more remarkable reduction of measured MMPs (p < 0.001 in all cases) and TIMP-1 level (p < 0.01). These findings were accompanied by significantly decreased ratios of measured MMPs to TIMP-1. Next rituximab infusions on weeks 24 and 26 sustained the suppression of serum MMPs levels. Prior to the initial rituximab infusion, serum concentrations of studied MMPs and TIMP-1 significantly correlated with markers of RA activity such as disease activity score (DAS28) and CRP levels. Rituximab therapy, beside a rapid clinical improvement, reduced serum MMPs concentrations in RA patients refractory to anti-TNF treatment. Repeated infusions of rituximab maintained initial serum MMPs suppression.

Functional changes in rheumatoid fibroblast-like synovial cells through activation of peroxisome proliferator-activated receptor gamma-mediated signalling pathway

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand dependent transcriptional factor known to be a regulator of adipogenesis. Recent studies have also shown that stimulation of PPARgamma inhibits the transcriptional activities of other nuclear factors and down-regulates proinflammatory cytokine synthesis in T cells and monocytes. We examined, in the present study, the functional significance of PPARgamma expressed in fibroblast-like synovial cells (FLS) isolated from patients with rheumatoid arthritis (RA). Incubation of FLS with a synthetic PPARgamma ligand, troglitazone, inhibited endogenous production of TNF-alpha, IL-6 and IL-8, as well as matrix metalloprotease-3 (MMP-3), without inducing apoptosis of the cells. The gelatinase activity of FLS culture media was also inhibited by troglitazone. Electrophoretic mobility shift assay (EMSA) showed a significant reduction in the DNA binding activity of NF-kappaB in troglitazone-treated FLS in response to TNF-alpha or IL-1beta. Moreover, long-term cultivation of FLS with troglitazone resulted in morphological changes with marked lipid accumulation in these cells. Our results show a negative regulatory function for PPARgamma on cytokine and MMP production together with inhibition of cytokine-mediated inflammatory responses in rheumatoid synovial cells. Our results also suggest that FLS could differentiate into adipocyte-like cells in the presence of proper stimulatory signals including PPARgamma.

Expression of membrane-type 1 matrix metalloproteinase in rheumatoid synovial cells

Membrane-type 1 matrix metalloproteinase (MT1-MMP) is thought to be a putative regulator of pro-gelatinase A (MMP-2) in the rheumatoid synovium. In this study, we examined the effects of IL-1beta, one of the inflammatory cytokines, on the expression of MT1-MMP and the activation of pro-MMP-2 using rheumatoid synovial cells. We also studied the effects of KE-298 (2-acetylthiomethyl-4-(4-methylphenyl)-4-oxobutanoic acid), a new disease-modifying anti-rheumatic drug (DMARD), on MT1-MMP expression of rheumatoid synovial cells. Type B synovial cells (fibroblast-like synovial cells) were cultured with KE-298 (25-100 microg/ml) in the presence of IL-1beta for 48 h. Activation of pro-MMP-2 secreted from synovial cells was analysed by gelatin zymography. Reverse transcription-polymerase chain reaction (RT-PCR) methods were used to detect MT1-MMP mRNA. MT1-MMP protein expression on synovial cells was examined by anti-MT1-MMP immunoblot. An active form of MMP-2 was demonstrated in the culture media conditioned by IL-1beta-stimulated synovial cells. In addition, MT1-MMP mRNA and protein expression of rheumatoid synovial cells were increased by IL-1beta treatment. KE-298 blocked this IL-1beta-induced pro-MMP-2 activation and MT1-MMP expression, but did not affect IL-1beta-induced tissue inhibitor of metalloproteinase-2 (TIMP-2) secretion from rheumatoid synovial cells. These findings indicate that activation of rheumatoid synovial cells by IL-1beta results in the induction of MT1-MMP expression. Given that MT1-MMP promotes matrix degradation by activating pro-MMP-2, these results suggest a novel mechanism whereby cytokine may contribute to articular destruction in rheumatoid arthritis (RA). KE-298 may prevent this process by down-regulating MT1-MMP expression.