Bone marrow mesenchymal stem cell-derived exosomes inhibit chondrocyte apoptosis and the expression of MMPs by regulating Drp1-mediated mitophagy

Osteoarthritis (OA) is a joint degenerative disease commonly seen in the elderly. Bone marrow mesenchymal stem cell-exosomes (BMSC-exosomes) are closely associated with the progression of OA. Here, we investigated whether BMSC-exosomes can affect OA development by regulating mitophagy. Primary rat chondrocytes were treated with advanced glycation end products (AGEs) to induce cell damage. The results of flow cytometry showed that AGEs treatment significantly promoted apoptosis of chondrocytes. AGEs treatment also enhanced the expression of matrix metalloproteinases (MMPs), MMP-3 and MMP-13, and dynamin-related protein 1 (Drp1) in chondrocytes. To investigate the impact of BMSC-exosomes on chondrocytes, chondrocytes were treated with BMSC-exosomes. AGEs-mediated increase of apoptosis and up-regulation of MMP-3, MMP-13, and Drp1 in chondrocytes were abrogated by BMSC-exosomes. Western blot analysis of autophagy-related proteins and Mito-Keima assay revealed that BMSC-exosome treatment elevated the expression of autophagy-related proteins, LC3-II/LC3-I and Beclin-1, and promoted mitophagy in the AGEs-treated chondrocytes. Moreover, Drp1 overexpression repressed the expression of LC3-II/LC3-I and Beclin-1, and enhanced apoptosis and the expression of MMP-3 and MMP-13 in AGEs-treated chondrocytes. BMSC-exosomes reversed the impact of Drp1 overexpression on AGEs-treated chondrocytes. In conclusion, this work demonstrates that BMSC-exosomes inhibit chondrocyte apoptosis and the expression of MMPs, which attributes to regulate Drp1-mediated mitophagy. Thus, BMSC-exosomes may be a potential treatment for OA.

Matrix metalloproteinases MMP-1, MMP-2, and MMP-13 are overexpressed in primary nodular melanoma

BACKGROUND

The spread and invasion of malignant melanoma cells involve degradation and reorganization of the extracellular matrix by the activation of several matrix metalloproteinases (MMPs). This study analyzed the expression of MMP-1, MMP-2, and MMP-13 proteins in primary nodular melanoma (NM) and dysplastic nevi (DN) as a significant risk factor for melanoma development. The secondary goal was to analyze the correlation of MMPs protein expression in NM with tumor invasion, BRAF V600 mutation status, and overall survival.

METHODS

Immunohistochemistry for MMP-1, MMP-2, and MMP-13 was performed on nodular melanoma (n = 52) and dysplastic nevi (n = 28) on tissue microarray (TMA). BRAF V600 mutation analysis on NM samples was performed by the Sanger sequencing method.

RESULTS

A high level of MMPs expression in NM samples (>30%) compared with DN (<8%) was statistically significant (P < 0.001). BRAF V600 mutations were detected in 15 of 39 (38.5%) NM samples. This study revealed an interesting finding that MMP-1 and MMP-13 protein expression in the BRAF V600 mutated melanomas were significantly lower than in the BRAF V600 wild type (P < 0.05).

CONCLUSION

Cox analysis revealed that Clark categories, Breslow thickness, and MMP-1 high protein expression are predictive factors for shorter overall survival (P < 0.05).

The protective effects of the GPR39 agonist TC-G 1008 against TNF-α-induced inflammation in human fibroblast-like synoviocytes (FLSs)

Rheumatoid arthritis (RA) is a common immune-mediated chronic inflammatory joint disease of unknown etiology. While tumor necrosis factor-α(TNF-α) blockers have proven to be a beneficial treatment option for many patients, not all respond to such treatments. In the present study, we investigate the role of the recently discovered zinc-sensing G protein-couple receptor GPR39. To our knowledge, this study is the first to investigate the role of GPR39 in the context of RA using human fibroblast-like synoviocytes (FLS). We found that agonism of GPR39 using its specific agonist TC-G 1008 significantly ameliorated important markers of RA, including oxidative stress, mitochondrial dysfunction, expression of proinflammatory cytokines including interleukin-1β (IL-1β), IL-6, and monocyte chemoattractant protein 1 (MCP-1), and secretion of key matrix metalloproteinases (MMPs) including MMP-1, MMP-3 and MMP-13. Furthermore, we demonstrate that these may be mediated via the Janus-kinase (JNK), activating protein 1 (AP-1), and nuclear factor-κB (NF-κB) cellular signaling pathways. Our findings demonstrate for the first time the potential of GPR39 to mediate synovial inflammation, pannus invasion, and enzymatic degradation of articular extracellular matrix.

Coordinated existence of multiple gangliosides is required for cartilage metabolism

OBJECTIVE

Gangliosides, ubiquitously existing membrane components that modulate transmembrane signaling and mediate cell-to-cell and cell-to-matrix interactions, are key molecules of inflammatory and neurological disorders. However, the functions of gangliosides in the cartilage degradation process remain unclear. We investigated the functional role of gangliosides in cartilage metabolism related to osteoarthritis (OA) pathogenesis.

DESIGN

We generated knockout (KO) mice by targeting the β1, 4-N-acetylgalactosaminyltransferase (GalNAcT) gene, which encodes an enzyme of major gangliosides synthesis, and the GD3 synthase (GD3S) gene, which encodes an enzyme of partial gangliosides synthesis. In vivo OA and in vitro cartilage degradation models were used to evaluate the effect of gangliosides on the cartilage degradation process.

RESULTS

The GalNAcT and GD3S KO mice developed and grew normally; nevertheless, OA changes in these mice were enhanced with aging. The GalNAcT KO mice showed significantly enhanced OA progression compared to GD3S mice in vivo. Both GalNAcT and GD3S KO mice showed severe IL-1α-induced cartilage degradation ex vivo. Phosphorylation of MAPKs was enhanced in both GalNAcT and GD3S KOs after IL-1α stimulation. Gangliosides modulated by GalNAcT or GD3S rescued an increase of MMP-13 induced by IL-1α in mice lacking GalNAcT or GD3S after exogenous replenishment in vitro.

CONCLUSION

These data show that the deletion of gangliosides in mice enhanced OA development. Moreover, the gangliosides modulated by GalNAcT are important for cartilage metabolism, suggesting that GalNAcT is a potential target molecule for the development of novel OA treatments.

Correlation of COX-2 and MMP-13 expressions with gastric cancer and their effects on prognosis

PURPOSE

To study the expressions of cyclooxygenase-2 (COX-2) and matrix metalloproteinase-13 (MMP-13) genes in gastric cancer, and to investigate the correlation between them and gastric cancer and their effects onprognosis.

METHODS

80 cases of tumor tissues and 40 cases of normal tumor-adjacent tissues were collected from patients with gastric cancer admitted to the Surgical Department of our hospital. The mRNA expression levels of COX-2 and MMP- 13 in tumor tissues and normal tumor-adjacent tissues were detected via real-time fluorescence reverse transcription polymerase chain reaction (RT-PCR). The expressions of COX-2 and MMP-13 in gastric cancer tissues and normal tumor-adjacent tissues were detected via immunohistochemical method. The clinical data of patients were recorded and the correlation between the COX-2 and MMP-13 expressions and the pathological parameters and prognosis of patients with gastric cancer were analyzed.

RESULTS

RT-PCR results showed that the mRNA expressions of COX-2 and MMP-13 in gastric cancer tissues were significantly higher than those in normal tumor-adjacent tissues. Immunohistochemical results showed that the positive expression rates of COX-2 and MMP-13 in gastric cancer tissues were 76.25% (60/80) and 71.25% (57/80), respectively and the high expression was related to the invasion, metastasis and tumor stage. The 5-year overall survival of patients was 16.6% (13/80). Single-factor survival analysis showed that both COX-2 and MMP-13 were factors influencing the overall survival of patients with gastric cancer (p<0.01).

CONCLUSION

The high expressions of COX-2 and MMP-13 are closely related to the pathological parameters of patients with gastric cancer, especially the invasion, metastasis and tumor stage. COX-2 and MMP-13 can be used as reference indexes to guide the treatment of gastric cancer and predict the disease prognosis.

Activation of MMPs in Macrophages by Mycobacterium tuberculosis via the miR-223-BMAL1 Signaling Pathway

An interaction between Mycobacterium tuberculosis and macrophages constitutes an essential step in tuberculosis development, as macrophages exert both positive and negative effects on M. tuberculosis-triggered organ lesions. In this study, we focused on the regulation of the expression of matrix metalloproteinases (MMPs), which is responsible for lung matrix degradation and bacteria dissection, in macrophages following M. tuberculosis infection. Female BALB/c mice were intravenously injected with the M. tuberculosis strain H37Rv at 0 h zeitgeber time (ZT0) or 12 h zeitgeber time (ZT12). The expression and activity of MMP-1, -2, -3, and -9 in lungs and spleens were then evaluated. In vitro, peritoneal macrophages were harvested at ZT0 or at ZT12 and infected with 10 MOI M. tuberculosis. The expression of MMPs, microRNA-223 and BMAL1 was analyzed by qRT-PCR and/or Western blot. The binding of BMAL1 3'-UTR by miR-223 was confirmed by luciferase activity assay. Additionally, wild-type BMAL1 or NLSmut BMAL1 plasmids were transfected to evaluate the effect of BMAL1 on MMPs. The results showed a differential expression of MMPs in mice tissues infected at different times. M. tuberculosis infection caused enhanced MMP-1, -9, and miR-223 expression, with inhibited BMAL1 expression. MiR-223 modulated BMAL1 expression via the direct binding of BMAL1 3'-UTR. Furthermore, wild-type BMAL1 other than NLSmut BMAL1 attenuated MMPs expression in M. tuberculosis-infected macrophages. Overall, this study demonstrated a potential involvement of circadian rhythm in MMP activation by M. tuberculosis in macrophages. J. Cell. Biochem. 118: 4804-4812, 2017. © 2017 Wiley Periodicals, Inc.

Fibroblast-growth factor 23 promotes terminal differentiation of ATDC5 cells

Objectives

Fibroblast Growth Factor 23 (FGF23) is well documented as a crucial player in the systemic regulation of phosphate homeostasis. Moreover, loss-of-function experiments have revealed that FGF23 also has a phosphate-independent and local impact on skeletogenesis. Here, we used ATDC5 cell line to investigate the expression of FGF23 and the role it may play locally during the differentiation of these cells.

Methods

ATDC5 cells were differentiated in the presence of insulin, and treated with recombinant FGF23 (rFGF23), inorganic phosphate (Pi) and/or PD173074, an inhibitor of FGF receptors (FGFRs). The mRNA expressions of FGF23, FGFRs and markers of hypertophy, Col X and MMP13, were determined by qPCR analysis and FGF23 production was assessed by ELISA. FGFR activation was determined by immunoprecipitation and immunoblotting.

Results

FGF23 mRNA expression and production were increased during ATDC5 differentiation. At D28 in particular, rFGF23 stimulation increased hypertrophic markers expression, as Col X and MMP13, and mineralization. A synergic effect of Pi and rFGF23 stimulation was observed on these markers and on the mineralization process. The use of PD173074, a pan-FGFR inhibitor, decreased terminal differentiation of ATDC5 by preventing rFGF23 pro-hypertrophic effects.

Conclusions

Altogether, our results provide evidence that FGF23 plays an important role during differentiation of ATDC5 cell line, by promoting both hypertrophy and mineralization.

Cytokine-induced MMP13 Expression in Human Chondrocytes Is Dependent on Activating Transcription Factor 3 (ATF3) Regulation

Irreversible breakdown of cartilage extracellular matrix (ECM) by the collagenase matrix metalloproteinase 13 (MMP13) represents a key event in osteoarthritis (OA) progression. Although inflammation is most commonly associated with inflammatory joint diseases, it also occurs in OA and is thus relevant to the prevalent tissue destruction. Here, inflammation generates a cFOS AP-1 early response that indirectly affects MMP13 gene expression. To ascertain a more direct effect on prolonged MMP13 production we examined the potential molecular events occurring between the rapid, transient expression of cFOS and the subsequent MMP13 induction. Importantly, we show MMP13 mRNA expression is mirrored by nascent hnRNA transcription. Employing ChIP assays, cFOS recruitment to the MMP13 promoter occurs at an early stage prior to gene transcription and that recruitment of transcriptional initiation markers also correlated with MMP13 expression. Moreover, protein synthesis inhibition following early FOS expression resulted in a significant decrease in MMP13 expression thus indicating a role for different regulatory factors modulating expression of the gene. Subsequent mRNA transcriptome analyses highlighted several genes induced soon after FOS that could contribute to MMP13 expression. Specific small interfering RNA-mediated silencing highlighted that ATF3 was as highly selective for MMP13 as cFOS. Moreover, ATF3 expression was AP-1(cFOS/cJUN)-dependent and expression levels were maintained after the early transient cFOS response. Furthermore, ATF3 bound the proximal MMP13 AP-1 motif in stimulated chondrocytes at time points that no longer supported binding of FOS Consequently, these findings support roles for both cFOS (indirect) and ATF3 (direct) in effecting MMP13 transcription in human chondrocytes.

Ethanol extract of Terminalia chebula fruit protects against UVB-induced skin damage

CONTEXT

The fruit of Terminalia chebula Retz. (Combretaceae) has been used for several therapeutic purposes in Thai folk medicines. Currently, the ethanol extracts containing antioxidant compounds have shown the ability to promote collagen synthesis.

OBJECTIVE

This purpose of this work was to study the effects of the ethanol extract from T. chebula fruit on the inhibition of cutaneous photodamage.

MATERIALS AND METHODS

The viability of human skin fibroblasts after incubation with T. chebula at concentration 0.5-50 μg/mL for 24, 48 and 72 h was assessed by using sodium 3'-[(phenyl-amino)-carbonyl]-3,4,tetrazolium-bis(4-methoxy-6-notro)benzene-sulphonic acid hydrate (XTT). The levels of type I procollagen and matrix metalloproteinases (MMP)-1 and MMP-13 produced by UVB-irradiated fibroblasts were determined by ELISA. Skin thickness and collagen content caused by long-term UVB irradiation in male ICR mice were determined from haematoxylin and eosin stained tissue sections and spectrophotometric measurement of hydroxyproline.

RESULTS

The extract (0.5-50 μg/mL) had no effect on cell viability or morphology of the human fibroblasts. In vitro studies showed that the T. chebula extract reduced the UVB-induced MMP-1 and MMP-13 expression, whereas an increased production of type I procollagen was observed. In a UVB-irradiated animal model, male ICR mice with hair shaved were chronically exposed to UVB which lead to epidermal thickness and loss of hydroxyproline. However, these effects were fully prevented by the topical application of the T. chebula ethanol extract.

DISCUSSION AND CONCLUSION

These data suggested that the T. chebula ethanol fruit extract is an efficacious pharmaceutical protectant of skin against photodamage.

Identification of Targets of a New Nutritional Mixture for Osteoarthritis Management Composed by Curcuminoids Extract, Hydrolyzed Collagen and Green Tea Extract

Objective

We have previously demonstrated that a mixture of curcuminoids extract, hydrolyzed collagen and green tea extract (COT) inhibited inflammatory and catabolic mediator’s synthesis by osteoarthritic human chondrocytes. The objective of this study was to identify new targets of COT using genomic and proteomic approaches.

Design

Cartilage specimens were obtained from 12 patients with knee osteoarthritis. Primary human chondrocytes were cultured in monolayer until confluence and then incubated for 24 or 48 hours in the absence or in the presence of human interleukin(IL)-1β (10^-11M) and with or without COT, each compound at the concentration of 4 μg/ml. Microarray gene expression profiling between control, COT, IL-1β and COT IL-1β conditions was performed. Immunoassays were used to confirm the effect of COT at the protein level.

Results

More than 4000 genes were differentially expressed between conditions. The key regulated pathways were related to inflammation, cartilage metabolism and angiogenesis. The IL-1β stimulated chemokine ligand 6, matrix metalloproteinase-13, bone morphogenetic protein-2 and stanniocalcin1 gene expressions and protein productions were down-regulated by COT. COT significantly decreased stanniocalcin1 production in basal condition. Serpin E1 gene expression and protein production were down-regulated by IL-1β. COT reversed the inhibitory effect of IL-1β. Serpin E1 gene expression was up-regulated by COT in control condition.

Conclusion

The COT mixture has beneficial effect on osteoarthritis physiopathology by regulating the synthesis of key catabolic, inflammatory and angiogenesis factors. These findings give a scientific rationale for the use of these natural ingredients in the management of osteoarthritis.

The Long Noncoding RNA MALAT-1 Is Highly Expressed in Ovarian Cancer and Induces Cell Growth and Migration

BACKGROUND

Metastasis associated in lung adenocarcinoma transcript-1 (MALAT-1) is overexpressed during cancer progression and promotes cell migration and invasion in many solid tumors. However, its role in ovarian cancer remains poorly understood.

METHODS

Expressions of MALAT-1 were detected in 37 normal ovarian tissues and 45 ovarian cancer tissues by reverse transcription polymerase chain reaction (RT-PCR). Cell proliferation was observed by CCK-8 assay; Flow cytometry was used to measure cell cycle and apoptosis; Cell migration was detected by transwell migration and invasion assay. In order to evaluate the function of MALAT-1, shRNA combined with DNA microarray and Functional enrichment analysis were performed to determine the transcriptional effects of MALAT-1 silencing in OVCAR3 cells. RNA and protein expression were measured by qRT-PCR and Western blotting, respectively.

RESULTS

We found that upregulation of MALAT-1 mRNA in ovarian cancer tissues and enhanced MALAT-1 expression was associated with FIGO stage. Knockdown of MALAT-1 expression in OVCAR3 cells inhibited cell proliferation, migration, and invasion, leading to G0/G1 cell cycle arrest and apoptosis. Overexpressed MALAT-1 expression in SKOV3 cells promoted cell proliferation, migration and invasion. Downregulation of MALAT-1 resulted in significant change of gene expression (at least 2-fold) in 449 genes, which regulate proliferation, cell cycle, and adhesion. As a consequence of MALAT-1 knockdown, MMP13 protein expression decreased, while the expression of MMP19 and ADAMTS1 was increased.

CONCLUSIONS

The present study found that MALAT-1 is highly expressed in ovarian tumors. MALAT-1 promotes the growth and migration of ovarian cancer cells, suggesting that MALAT-1 may be an important contributor to ovarian cancer development.

E2 regulates MMP-13 via targeting miR-140 in IL-1β-induced extracellular matrix degradation in human chondrocytes

BACKGROUND

Estrogen deficiency is closely related to the development of menopausal arthritis. Estrogen replacement therapy (ERT) shows a protective effect against the osteoarthritis. However, the underlying mechanism of this protective effect is unknown. This study aimed to determine the role of miR-140 in the estrogen-dependent regulation of MMP-13 in human chondrocytes.

METHODS

Primary human articular chondrocytes were obtained from female OA patients undergoing knee replacement surgery. Normal articular chondrocytes were isolated from the knee joints of female donors after trauma and treated with interleukin-1 beta (IL-1β). Gene expression levels of miR-140, MMP-13, and ADAMTS-5 were detected by quantitative real-time PCR (qRT-PCR). miR-140 levels were upregulated or downregulated by transfecting cells with a miRNA mimic and inhibitor, respectively, prior to treatment with IL-1β. MMP-13 expression was then evaluated by Western blotting and immunofluorescence. Luciferase reporter assays were performed to verify the interaction between miR-140 and ER.

RESULTS

17-β-estradiol (E2) suppressed MMP-13 expression in human articular chondrocytes. miR-140 expression was upregulated after estrogen treatment. Knockdown of miR-140 expression abolished the inhibitory effect of estrogen on MMP-13. In addition, the estrogen/ER/miR-140 pathway showed an inhibitory effect on IL-1β-induced cartilage matrix degradation.

CONCLUSIONS

This study suggests that estrogen acts via ER and miR-140 to inhibit the catabolic activity of proteases within the chondrocyte extracellular matrix. These findings provide new insight into the mechanism of menopausal arthritis and indicate that the ER/miR-140 signaling pathway may be a potential target for therapeutic interventions for menopausal arthritis.

Insulin decreases autophagy and leads to cartilage degradation

OBJECTIVE

Autophagy, a key homeostasis mechanism, is defective in Osteoarthritis (OA) and Type 2 Diabetes (T2D). T2D has been proposed as a risk factor for OA. We hypothesized that diabetes impairs articular cartilage integrity by decreasing autophagy. Our objective was to investigate the effects of high glucose and insulin, characteristics of T2D, on cartilage homeostasis.

METHODS

Immortalized human chondrocytes (TC28a2) and primary human chondrocytes (HC) were cultured in 25 mM or 0 mM glucose and treated with insulin (10, 100, 500 nM) for 2, 6 or 24 h. Activity of LC3-II, Akt and rpS6 was evaluated by Western blotting (WB). Human cartilage explants were cultivated with 25 mM glucose and insulin (100,1000 nM) for 24 h to evaluate histopathology. MMP-13 and IL-1β expression was determined by immunohistochemistry and WB. Effects of Rapamycin (10 μM) were analyzed by WB. LC3 and rpS6 expression was determined by WB in chondrocytes from Healthy, Non Diabetic-OA and Diabetic-OA patients.

RESULTS

Insulin downregulates autophagy by reducing LC3 II expression and increasing Akt and rpS6 phosphorylation. Loss of proteoglycans and increased MMP-13 and IL-1β expression was observed after insulin treatment. Autophagy activation by rapamycin reversed insulin effects. Importantly, chondrocytes from diabetic-OA patients showed decreased LC3 and increased p-rpS6 expression compared to Healthy and Non-Diabetic OA patients.

CONCLUSIONS

These results suggest that decreased autophagy might be a mechanism by which diabetes influences cartilage degradation. Pharmacological activation of autophagy may be an effective therapeutic approach to prevent T2D-induced cartilage damage.

Visfatin Destabilizes Atherosclerotic Plaques in Apolipoprotein E-Deficient Mice

Objectives

Although there is evidence that visfatin is associated with atherogenesis, the effect of visfatin on plaque stability has not yet been explored.

Methods

In vivo, vulnerable plaques were established by carotid collar placement in apolipoprotein E–deficient (ApoE^−/−) mice, and lentivirus expressing visfatin (lenti-visfatin) was locally infused in the carotid artery. The lipid, macrophage, smooth muscle cell (SMC) and collagen levels were evaluated, and the vulnerability index was calculated. In vitro, RAW264.7 cells were stimulated with visfatin, and the MMPs expressions were assessed by western blot and immunofluorescence. And the mechanism that involved in visfatin-induced MMP-8 production was investigated.

Results

Transfection with lenti-visfatin significantly promoted the expression of visfatin which mainly expressed in macrophages in the plaque. Lenti-visfatin transfection significantly promoted the accumulation of lipids and macrophages, modulated the phenotypes of smooth muscle cells and decreased the collagen levels in the plaques, which significantly decreased the plaque stability. Simultaneously, transfection with lenti-visfatin significantly up-regulated the expression of MMP-8 in vivo, as well as MMP-1, MMP-2 and MMP-9. Recombinant visfatin dose- and time-dependently up-regulated the in vitro expression of MMP-8 in macrophages. Visfatin promoted the translocation of NF-κB, and inhibition of NF-κB significantly reduced visfatin-induced MMP-8 production.

Conclusions

Visfatin increased MMP-8 expression, promoted collagen degradation and increased the plaques vulnerability index.

Involvement of acid-sensing ion channel 1a in matrix metabolism of endplate chondrocytes under extracellular acidic conditions through NF-κB transcriptional activity

Acidic conditions are present in degenerated intervertebral discs and are believed to be responsible for matrix breakdown. Acid-sensing ion channel 1a (ASIC1a) is expressed in endplate chondrocytes, and its activation is associated with endplate chondrocyte apoptosis. However, the precise role of ASIC1a in regulating the matrix metabolic activity of endplate chondrocytes in response to extracellular acid remains poorly understood. Aggrecan (ACAN), type II collagen (Col2a1), and matrix metalloproteinase (MMP) expressions were determined using reverse transcription (RT)-PCR and Western blot. ASIC1a was knocked down by transfecting endplate chondrocytes with ASIC1a siRNA. MMP activity and NF-κB transcriptional activity were measured. NF-κB transcriptional activity was assessed by examining cytosolic phosphorylated IκBα and nuclear phosphorylated p65 levels. Extracellular acidic solution (pH 6.0) resulted in a decrease in ACAN and Co12a1 expressions and an increase in MMP-1, MMP-9, and MMP-13 expressions, as well as in MMP activity; while ASIC1a siRNA blocked these effects. In addition, acid-induced increase in cytosolic levels of phosphorylated IκBα and nuclear levels of phosphorylated p65 in endplate chondrocytes were inhibited by ASIC1a siRNA. ASIC1a is involved in matrix metabolism of endplate chondrocytes under extracellular acidic conditions via NF-κB transcriptional activity.

Interleukin-1 Receptor Antagonist Has a Novel Function in the Regulation of Matrix Metalloproteinase-13 Expression

Interleukin-1 receptor antagonist (IL-1Ra) is an IL-1 family member, which binds to IL-1 receptors but does not induce any intracellular signaling. We addressed whether IL-1Ra has a novel function in regulation of the extracellular matrix or adhesion molecules. Polymerase chain reaction array analysis demonstrated a ~5-fold increase in matrix metalloproteinase 13 (MMP-13) mRNA expression of IL-1Ra siRNA-transfected Ca9-22 human oral squamous epithelial carcinoma cells compared with the control. In fact, MMP-13 mRNA and protein expression as well as its activity in IL-1Ra siRNA-transfected Ca9-22 cell lines were significantly higher than those in the control. IL-1Ra siRNA treatment resulted in strong elevation of MMP-13 expression, whereas addition of rhIL-1Ra (40 ng/ml) suppressed MMP-13 expression, suggesting that IL-1Ra had a specific effect on MMP-13 induction. IL-1Ra siRNA could potently suppress IL-1α. No significant difference was found between the MMP-13 mRNA expression of IL-1Ra siRNA-transfected cells and those treated with anti-IL-1α or anti-IL-1β antibodies. These results suggested that continuous supply of IL-1 had no effect on the induction of MMP-13 by IL-1Ra siRNA. Histopathological investigation of MMP-13 in periodontal tissue showed specific localization in the junctional epithelial cells of IL-1Ra knockout (KO) mice. Furthermore, infection with Aggregatibacter actinomycetemcomitans to establish an experimental periodontitis model resulted in predominant localization of MMP-13 along apical junctional epithelial cells. Laminin-5, which is degraded by MMP-13, was found in the internal basal lamina of wild-type mice, whereas the internal basal lamina of IL-1Ra KO mice did not show obvious laminin-5 localization. In particular, laminin-5 localization almost disappeared in the internal basal lamina of IL-1Ra KO mice infected with A. actinomycetemcomitans, suggesting that the suppression of IL-1Ra resulted in strong induction of MMP-13 that degraded laminin-5. In conclusion, IL-1Ra is associated with MMP-13 expression and has a novel function in such regulation without interference of the IL-1 signaling cascade.

Suppressive Effect of Dietary Fucoidan on Proinflammatory Immune Response and MMP-1 Expression in UVB-Irradiated Mouse Skin

It is well known that ultraviolet B irradiation leads to dermal inflammation. In this study, we found that Mekabu fucoidan suppressed edema, decreased the thickness of the prickle cell layer, and decreased matrix metalloproteinase 1 in the skin of mice irradiated with ultraviolet B. Moreover, we found that the mean level of interferon gamma of Mekabu fucoidan-treated, ultraviolet B-irradiated mice (approximately 2.2 ng/mL) was not significantly different from that in normal mice (approximately 2.5 ng/mL). In contrast, a significant decrease in the mean level of interferon gamma (approximately 1.3 ng/mL) in ultraviolet B-irradiated control mice was observed compared with that in Mekabu fucoidan-treated, ultraviolet B-irradiated mice. The mean thickness of the prickle cell layer in the skin of Mekabu fucoidan-treated, ultraviolet B-irradiated mice was less than that in the ultraviolet B-irradiated control mice. Metalloproteinase 1 activity was significantly higher in the skin of ultraviolet B-irradiated mice than in the skin of untreated, nonirradiated normal mice. Metalloproteinase 1 in the skin of ultraviolet B-irradiated, Mekabu fucoidan- or L(+)-ascorbic acid (vitamin C)-treated mice was significantly lower than that in the ultraviolet B-irradiated control mice. Mitigation of the morphological changes in Mekabu fucoidan-treated mice was correlated with a decrease in metalloproteinase 1 levels. These data indicate that Mekabu fucoidan is an effective suppressor of inflammation in an ultraviolet B-irradiated mouse model.

Inhibitory effects of EGb761 on the expression of matrix metalloproteinases (MMPs) and cartilage matrix destruction

Cytokines such as tumor necrosis factor alpha (TNF-α)-induced expression of matrix metalloproteinase (MMP) play a pivotal role in the destruction of articular cartilage in patients who are suffering from osteoarthritis (OA). Collagen type II, the basis for articular cartilage, can be degraded by MMP-1, MMP-3, and 13. EGb761, the standardized extract of Ginkgo biloba produced by Dr. Willar Schwabe Pharmaceuticals, has shown its anti-inflammatory capacity. This study aimed to determine a mechanism whereby EGb761 may inhibit cartilage degradation. Our results indicated that pretreatment with EGb761 abolishes MMP-1, MMP-3, and MMP-13 gene expression and protein expression induced by TNF-α in human chondrocyte monolayer. In addition, the reduction of the tissue inhibitor of metalloproteinase-1(TIMP-1) and metalloproteinase-2 gene expression induced by TNF-α was rescued by pretreatment with EGb761. Importantly, TNF-α-induced degradation of collagen type II was ameliorated by EGb761 in a dose-dependent manner. Mechanistically, our results indicated that EGb761 treatment attenuated TNF-α-induced NF-κB activation. These actions of EGb761 suggest a mechanism by which EGb761 may act to prevent cartilage breakdown in arthritis.

SERPINE2 Inhibits IL-1α-Induced MMP-13 Expression in Human Chondrocytes: Involvement of ERK/NF-κB/AP-1 Pathways

OBJECTIVES

Osteoarthritis (OA) is a chronic joint disease, characterized by a progressive loss of articular cartilage. During OA, proinflammatory cytokines, such as interleukin IL-1, induce the expression of matrix metalloproteinases (MMPs) in chondrocytes, contributing thus to the extracellular matrix (ECM) degradation. Members of Serpine family, including plasminogen activator inhibitors have been reported to participate in ECM regulation. The aim of this study was to assess the expression of serpin peptidase inhibitor clade E member 2 (SERPINE2), under basal conditions and in response to increasing doses of IL-1α, in human cultured chondrocytes. We also examined the effects of SERPINE2 on IL-1α-induced MMP-13 expression. For completeness, the signaling pathway involved in this process was also explored.

METHODS

SERPINE2 mRNA and protein expression were evaluated by RT-qPCR and western blot analysis in human T/C-28a2 cell line and human primary chondrocytes. These cells were treated with human recombinant SERPINE2, alone or in combination with IL-1α. ERK 1/2, NFκB and AP-1 activation were assessed by western blot analysis.

RESULTS

Human cultured chondrocytes express SERPINE2 in basal condition. This expression increased in response to IL-1α stimulation. In addition, recombinant SERPINE2 induced a clear inhibition of MMP-13 expression in IL-1α-stimulated chondrocytes. This inhibitory effect is likely regulated through a pathway involving ERK 1/2, NF-κB and AP-1.

CONCLUSIONS

Taken together, these data demonstrate that SERPINE2 might prevent cartilage catabolism by inhibiting the expression of MMP-13, one of the most relevant collagenases, involved in cartilage breakdown in OA.

Microencapsulated equine mesenchymal stromal cells promote cutaneous wound healing in vitro

INTRODUCTION

The prevalence of impaired cutaneous wound healing is high and treatment is difficult and often ineffective, leading to negative social and economic impacts for our society. Innovative treatments to improve cutaneous wound healing by promoting complete tissue regeneration are therefore urgently needed. Mesenchymal stromal cells (MSCs) have been reported to provide paracrine signals that promote wound healing, but (i) how they exert their effects on target cells is unclear and (ii) a suitable delivery system to supply these MSC-derived secreted factors in a controlled and safe way is unavailable. The present study was designed to provide answers to these questions by using the horse as a translational model. Specifically, we aimed to (i) evaluate the in vitro effects of equine MSC-derived conditioned medium (CM), containing all factors secreted by MSCs, on equine dermal fibroblasts, a cell type critical for successful wound healing, and (ii) explore the potential of microencapsulated equine MSCs to deliver CM to wounded cells in vitro.

METHODS

MSCs were isolated from the peripheral blood of healthy horses. Equine dermal fibroblasts from the NBL-6 (horse dermal fibroblast cell) line were wounded in vitro, and cell migration and expression levels of genes involved in wound healing were evaluated after treatment with MSC-CM or NBL-6-CM. These assays were repeated by using the CM collected from MSCs encapsulated in core-shell hydrogel microcapsules.

RESULTS

Our salient findings were that equine MSC-derived CM stimulated the migration of equine dermal fibroblasts and increased their expression level of genes that positively contribute to wound healing. In addition, we found that equine MSCs packaged in core-shell hydrogel microcapsules had similar effects on equine dermal fibroblast migration and gene expression, indicating that microencapsulation of MSCs does not interfere with the release of bioactive factors.

CONCLUSIONS

Our results demonstrate that the use of CM from MSCs might be a promising new therapy for impaired cutaneous wounds and that encapsulation may be a suitable way to effectively deliver CM to wounded cells in vivo.

Animal and cellular models of hepatocellular carcinoma bone metastasis: establishment and characterisation

BACKGROUND

An increasingly high occurrence of bone metastases in hepatocellular carcinoma (HCC) patients highlights the importance of fundamental research on HCC bone metastasis, which has been limited in its success due to the lack of a model system.

PURPOSE

Establishment of animal and cellular models of HCC bone metastasis and discovery of HCC bone metastasis-related genes.

METHODS

Luciferase-transfected HCC cell lines HCCLM3, MHCC97H, and SMMC-7721 were used to inoculate nude mice intracardially. Formation of bone metastases was examined by bioluminescence imaging, SPECT, and pathology study. Metastatic cells in bone were isolated and subcultured. Differences between bone metastatic cells and their parental cells were studied by in vitro/in vivo assays.

RESULTS

Mouse model of HCC bone metastasis was successfully established. Injected tumour cells formed metastases in the skull, the spine, the hind limbs, and the sternum, causing osteolytic lesions via act of MMP-1 and recruitment of osteoclasts. Four bone metastatic cell lines were extracted from HCCLM3-inoculated mice and were demonstrated to exhibit a much stronger ability to form bone metastases as well as other phenotypes, including enhanced in vitro migration/invasion and colony formation. Moreover, the expression of PTHrP, MMP-1, and CTGF was significantly elevated in bone metastatic cells compared to parental HCC cells.

CONCLUSION

The nude mouse model and bone metastatic cell lines together provide an effective simulation of HCC bone metastasis. This model system will become powerful tool with which to explore the mechanisms and therapies of HCC bone metastasis. Additionally, PTHrP, MMP-1, and CTGF are candidate genes related to HCC bone metastasis.

Signatures of resistance to Lepeophtheirus salmonis include a TH2-type response at the louse-salmon interface

Disease outbreaks with the salmon louse Lepeophtheirus salmonis cause significant economic losses in mariculture operations worldwide. Variable innate immune responses at the louse-attachment site contribute to differences in susceptibility among species such that members of Salmo spp. are more susceptible to infection than those of some Oncorhynchus spp. Relatively little is known about the mechanisms that contribute to disease resistance or susceptibility to L. salmonis in salmon. Here, we utilize histochemistry and transcriptomics in a comparative infection model with susceptible (Atlantic, sockeye) and resistant (coho) salmon. At least three cell populations (MHIIβ+, IL1β+, TNFα+) were activated in coho salmon skin during L. salmonis infection. Locally elevated expression of several pro-inflammatory mediators (e.g. IL1β, IL8, TNFα, COX2, C/EBPβ), and tissue repair enzymes (MMP9, MMP13) were detected in susceptible and resistant species. However, responses specific to coho salmon (e.g. IL4, IL6, TGFβ) or responses shared among susceptible salmon (e.g. SAP, TRF, Cath in Atlantic and sockeye salmon) provide evidence for species-specific pathways contributing to resistance or susceptibility, respectively. Our results confirm the importance of an early pro-inflammatory TH1-type pathway as an initial host response during infection with Pacific sea lice, and demonstrate subsequent regulatory TH2-type processes as candidate defense mechanisms in the skin of resistant coho salmon.

Exploring the osteoarthritis-related genes by gene expression analysis

OBJECTIVE

Osteoarthritis (OA) is a most common chronic degenerative joint lesion, which affects both cartilage and bone. A better understanding of the gene expression profiling of OA may help understanding the pathogenesis of OA and finding the therapy targets for OA treatment.

MATERIALS AND METHODS

GSE8077 was downloaded from Gene Expression Omnibus (GEO) including 5 OA rats induced by anterior cruciate ligament transection and partial medial meniscectomy and 5 rats that were performed sham surgery as control. Differentially expressed genes (DEGs) between OA group and control group were identified by t-test with p < 0.05 and the coding genes that transcription factors corresponded were screened by TRANSFAC. Then Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis for DEGs and transcription factors were performed. The DEGs and transcription factors were integrated with information from STRING database to construct PPI network.

RESULTS

A total of 119 up-regulated genes, 39 down-regulated genes and 9 transcription factors were identified in OA sample. The GO enrichment analysis showed that 119 up-regulated genes were significantly enriched in blood vessel development and KEGG pathway enrichment showed that genes were involved in circadian rhythm pathway. In the PPI network, Cd44, Mmp13, Timp1 and Igf1 showed higher degrees.

CONCLUSIONS

The screened genes could provide a new and comprehensive view for treatment of OA.

Mesenchymal precursor cells maintain the differentiation and proliferation potentials of breast epithelial cells

INTRODUCTION

Stromal-epithelial interactions play a fundamental role in tissue homeostasis, controlling cell proliferation and differentiation. Not surprisingly, aberrant stromal-epithelial interactions contribute to malignancies. Studies of the cellular and molecular mechanisms underlying these interactions require ex vivo experimental model systems that recapitulate the complexity of human tissue without compromising the differentiation and proliferation potentials of human primary cells.

METHODS

We isolated and characterized human breast epithelial and mesenchymal precursors from reduction mammoplasty tissue and tagged them with lentiviral vectors. We assembled heterotypic co-cultures and compared mesenchymal and epithelial cells to cells in corresponding monocultures by analyzing growth, differentiation potentials, and gene expression profiles.

RESULTS

We show that heterotypic culture of non-immortalized human primary breast epithelial and mesenchymal precursors maintains their proliferation and differentiation potentials and constrains their growth. We further describe the gene expression profiles of stromal and epithelial cells in co-cultures and monocultures and show increased expression of the tumor growth factor beta (TGFβ) family member inhibin beta A (INHBA) in mesenchymal cells grown as co-cultures compared with monocultures. Notably, overexpression of INHBA in mesenchymal cells increases colony formation potential of epithelial cells, suggesting that it contributes to the dynamic reciprocity between breast mesenchymal and epithelial cells.

CONCLUSIONS

The described heterotypic co-culture system will prove useful for further characterization of the molecular mechanisms mediating interactions between human normal or neoplastic breast epithelial cells and the stroma, and will provide a framework to test the relevance of the ever-increasing number of oncogenomic alterations identified in human breast cancer.

[Effect of laminarin polysaccharide on activity of matrix metalloproteinase in photoaging skin]

OBJECTIVE

To study the effect of laminarin polysaccharide (LP) on the activity of matrix metalloproteinase of photoaging skins.

METHOD

Kunming SPF mice were prepared with back hair shaved, and randomly divided into the control group, the model group, the LP low does group (LP-L, 1 mg x kg(-1)), the LP high dose group (LP-H, 5 mg x kg(-1)) and the Vit E (100 mg x kg(-1)) group. They were abdominally injected with drugs twice on a daily basis. Except for the control group, all groups were exposed to ultraviolet rays for 1 hour every day, five times on a weekly basis, with accumulated exposure dose of UVB being 21.60 J x cm(-2) and accumulated exposure dose of UVA being 84.02 J x cm(-2). Eight weeks later, exposed back skins were collected to detect thickness of dermis by HE stain, content of hydroxyproline (Hyp) by chemical colorimetry, and serum MMP-1 and TIMP-1 content by ELISA. In addition, matrix metalloproteinase-1 (MMP-1) mRNA and relative content of tissue inhibitor of metalloproteinase-1 (TIMP1) mRNA was analyzed with Real-time PCR.

RESULT

Compared with the model group, the LP-H group could significantly increase the thickness of dermis, skin Hyp content and serum TIMP-1 level, and decrease relative content of MMP-1 mRNA in skin and MMP-1 content in serum.

CONCLUSION

LP can regulate the metabolism of collagen photoaging skins by adjusting the activity of matrix metalloproteinase.

Salubrinal reduces expression and activity of MMP13 in chondrocytes

OBJECTIVE

Stress to the endoplasmic reticulum (ER) and inflammatory cytokines induce expression and activity of matrix metalloproteinase 13 (MMP13). Since a synthetic agent, salubrinal, is known to alleviate ER stress and attenuate nuclear factor kappa B (NFκB) signaling, we addressed a question whether upregulation of MMP13 by ER stress and cytokines is suppressed by administration of salubrinal.

METHODS

Using C28/I2 human chondrocytes, we applied ER stress with tunicamycin and inflammatory distress with tumor necrosis factor α (TNFα) and interleukin 1β (IL1β). RNA interference with siRNA specific to NFκB p65 (RelA) was employed to examine a potential involvement of NFκB signaling in salubrinal's action in regulation of MMP13. We also employed primary human chondrocytes and evaluated MMP13 activity.

RESULTS

The result showed that tunicamycin activated p38 mitogen-activated protein kinase (MAPK), while inflammatory cytokines activated p38 MAPK and NFκB. In both cases, salubrinal significantly reduced expression and activity of MMP13. Silencing NFκB reduced inflammatory cytokine-driven upregulation of MMP13 activity.

CONCLUSIONS

The results demonstrate that salubrinal downregulates expression and activity MMP13 through p38 and NFκB signaling, suggesting its potential usage to treat degenerative diseases such as osteoarthritis.

Osterix regulates calcification and degradation of chondrogenic matrices through matrix metalloproteinase 13 (MMP13) expression in association with transcription factor Runx2 during endochondral ossification

Endochondral ossification is temporally and spatially regulated by several critical transcription factors, including Sox9, Runx2, and Runx3. Although the molecular mechanisms that control the late stages of endochondral ossification (e.g. calcification) are physiologically and pathologically important, these precise regulatory mechanisms remain unclear. Here, we demonstrate that Osterix is an essential transcription factor for endochondral ossification that functions downstream of Runx2. The global and conditional Osterix-deficient mice studied here exhibited a defect of cartilage-matrix ossification and matrix vesicle formation. Importantly, Osterix deficiencies caused the arrest of endochondral ossification at the hypertrophic stage. Microarray analysis revealed that matrix metallopeptidase 13 (MMP13) is an important target of Osterix. We also showed that there exists a physical interaction between Osterix and Runx2 and that these proteins function cooperatively to induce MMP13 during chondrocyte differentiation. Most interestingly, the introduction of MMP13 stimulated the calcification of matrices in Osterix-deficient mouse limb bud cells. Our results demonstrated that Osterix was essential to endochondral ossification and revealed that the physical and functional interaction between Osterix and Runx2 were necessary for the induction of MMP13 during endochondral ossification.

Beneficial effect of a sturgeon-based bioactive compound on gene expression of tumor necrosis factor-alpha, matrix metalloproteinases and type-10 collagen in human chondrocytes

In the present study, we examined the effect of a marine bioactive compound containing high-purity caviar-derived DNA, collagen elastin and protein extracts from sturgeon (LD-1227, Caviarlieri, Laboratoires Dom, Switzerland) on IL-1beta-induced activation and production of TNFalpha and MMP-13 in human osteo-arthritis (OA) chondrocytes and intracellular signaling factors. Human chondrocytes were derived from OA cartilage and stimulated with IL-1beta. Gene expression of TNFalpha, MMP-13, MMP-1 and Col10A1 was measured by quantitative RT-PCR. TNFalpha protein in culture medium was determined using cytokine-specific ELISA. Western immunoblotting was used to analyze the MMP-13 production in the culture medium and the activation of NF-kB. DNA binding activity of NF-kB p65 was determined using a highly sensitive and specific ELISA. MMP-13 activity in the culture medium was assayed by gelatine zymography. LD-1227 significantly decreased IL-1beta-stimulated gene expression and production of TNFalpha, MMP-1, MMP-13 and Col10A1 in human chondrocytes. The inhibitory effect of LD-1227 on the IL-1beta-induced expression of these genes was mediated at least in part via suppression of NF-kB p65. These data show that LD-1227 can inhibit IL-1beta-induced proliferation and inflammatory reactions via inhibited activation of the transcription factor NF-kB pathway in human chondrocytes derived from OA patients. These novel pharmacological actions of LD-1227 on IL-1beta-stimulated human OA chondrocytes provide suggestions that this marine biology compound may inhibit cartilage degradation by suppressing IL-1beta-mediated activation and the catabolic response in human chondrocytes.

The glial scar-monocyte interplay: a pivotal resolution phase in spinal cord repair

The inflammatory response in the injured spinal cord, an immune privileged site, has been mainly associated with the poor prognosis. However, recent data demonstrated that, in fact, some leukocytes, namely monocytes, are pivotal for repair due to their alternative anti-inflammatory phenotype. Given the pro-inflammatory milieu within the traumatized spinal cord, known to skew monocytes towards a classical phenotype, a pertinent question is how parenchymal-invading monocytes acquire resolving properties essential for healing, under such unfavorable conditions. In light of the spatial association between resolving (interleukin (IL)-10 producing) monocytes and the glial scar matrix chondroitin sulfate proteoglycan (CSPG), in this study we examined the mutual relationship between these two components. By inhibiting the de novo production of CSPG following spinal cord injury, we demonstrated that this extracellular matrix, mainly known for its ability to inhibit axonal growth, serves as a critical template skewing the entering monocytes towards the resolving phenotype. In vitro cell culture studies demonstrated that this matrix alone is sufficient to induce such monocyte polarization. Reciprocal conditional ablation of the monocyte-derived macrophages concentrated at the lesion margins, using diphtheria toxin, revealed that these cells have scar matrix-resolving properties. Replenishment of monocytic cell populations to the ablated mice demonstrated that this extracellular remodeling ability of the infiltrating monocytes requires their expression of the matrix-degrading enzyme, matrix metalloproteinase 13 (MMP-13), a property that was found here to be crucial for functional recovery. Altogether, this study demonstrates that the glial scar-matrix, a known obstacle to regeneration, is a critical component skewing the encountering monocytes towards a resolving phenotype. In an apparent feedback loop, monocytes were found to regulate scar resolution. This cross-regulation between the glial scar and monocytes primes the resolution of this interim phase of spinal cord repair, thereby providing a fundamental platform for the dynamic healing response.

Effect of CCN2 on FGF2-induced proliferation and MMP9 and MMP13 productions by chondrocytes

CCN2 (also known as connective tissue growth factor) interacts with several growth factors involved in endochondral ossification via its characteristic four modules and modifies the effect of such growth factors. Presently we investigated whether CCN2 interacts with fibroblast growth factor 2 (FGF2). Solid-phase binding assay, immunoprecipitation-Western blot analysis, and surface plasmon resonance (SPR) spectroscopy revealed that the C-terminal module of CCN2 (CT) directly bound to FGF2 with a dissociation constant of 5.5 nm. Next, we examined the combinational effects of CCN2 and FGF2 on the proliferation of and matrix metalloproteinase (MMP)-9 and -13 productions by cultured chondrocytes. FGF2 promoted not only the proliferation but also the production of MMP9 and -13, however, combined of FGF2 with CT module nullified the enhancement of both MMP productions and proliferation. To clarify the mechanism, we investigated the binding of CCN2 or its CT module to FGF receptor 1. As a result, we found that CCN2 bound to FGF receptor 1 with a dissociation constant of 362 nm, whereas the CT module did not. In addition, when we tested FGF signaling in chondrocytic HCS-2/8 cells stimulated by the combination of FGF2 with CT module, the level of ERK1/2, p38 MAPK, and c-Jun N-terminal kinase phosphorylation was decreased compared with that found with FGF2 alone. These findings suggest that CCN2 may regulate the proliferation and matrix degradation of chondrocytes by forming a complex with FGF2 as a novel modulator of FGF2 functions.

Microarray and proteomic analysis of breast cancer cell and osteoblast co-cultures: role of osteoblast matrix metalloproteinase (MMP)-13 in bone metastasis

Dynamic reciprocal interactions between a tumor and its microenvironment impact both the establishment and progression of metastases. These interactions are mediated, in part, through proteolytic sculpting of the microenvironment, particularly by the matrix metalloproteinases, with both tumors and stroma contributing to the proteolytic milieu. Because bone is one of the predominant sites of breast cancer metastases, we used a co-culture system in which a subpopulation of the highly invasive human breast cancer cell line MDA-MB-231, with increased propensity to metastasize to bone, was overlaid onto a monolayer of differentiated osteoblast MC3T3-E1 cells in a mineralized osteoid matrix. CLIP-CHIP® microarrays identified changes in the complete protease and inhibitor expression profile of the breast cancer and osteoblast cells that were induced upon co-culture. A large increase in osteoblast-derived MMP-13 mRNA and protein was observed. Affymetrix analysis and validation showed induction of MMP-13 was initiated by soluble factors produced by the breast tumor cells, including oncostatin M and the acute response apolipoprotein SAA3. Significant changes in the osteoblast secretomes upon addition of MMP-13 were identified by degradomics from which six novel MMP-13 substrates with the potential to functionally impact breast cancer metastasis to bone were identified and validated. These included inactivation of the chemokines CCL2 and CCL7, activation of platelet-derived growth factor-C, and cleavage of SAA3, osteoprotegerin, CutA, and antithrombin III. Hence, the influence of breast cancer metastases on the bone microenvironment that is executed via the induction of osteoblast MMP-13 with the potential to enhance metastases growth by generating a microenvironmental amplifying feedback loop is revealed.

TLR4 protein contributes to cigarette smoke-induced matrix metalloproteinase-1 (MMP-1) expression in chronic obstructive pulmonary disease

Cigarette smoke is the major risk factor associated with the development of chronic obstructive pulmonary disease and alters expression of proteolytic enzymes that contribute to disease pathology. Previously, we reported that smoke exposure leads to the induction of matrix metalloproteinase-1 (MMP-1) through the activation of ERK1/2, which is critical to the development of emphysema. To date, the upstream signaling pathway by which cigarette smoke induces MMP-1 expression has been undefined. This study demonstrates that cigarette smoke mediates MMP-1 expression via activation of the TLR4 signaling cascade. In vitro cell culture studies demonstrated that cigarette smoke-induced MMP-1 was regulated by TLR4 via MyD88/IRAK1. Blockade of TLR4 or inhibition of IRAK1 prevented cigarette smoke induction of MMP-1. Mice exposed to acute levels of cigarette smoke exhibited increased TLR4 expression. To further confirm the in vivo relevance of this signaling pathway, rabbits exposed to acute cigarette smoke were found to have elevated TLR4 signaling and subsequent MMP-1 expression. Additionally, lungs from smokers exhibited elevated TLR4 and MMP-1 levels. Therefore, our data indicate that TLR4 signaling, through MyD88 and IRAK1, plays a predominant role in MMP-1 induction by cigarette smoke. The identification of the TLR4 pathway as a regulator of smoke-induced protease production presents a series of novel targets for future therapy in chronic obstructive pulmonary disease.

Prostaglandin EP2 receptor signalling inhibits the expression of matrix metalloproteinase 13 in human osteoarthritic chondrocytes

OBJECTIVES

Matrix metalloproteinase (MMP) 13 is a pathogenic collagenase that causes cartilage destruction and plays a leading role in causing osteoarthritis. This study focused on 114 genes that are differentially expressed between intact and damaged osteoarthritis cartilage, in order to determine which molecules are involved in suppressing MMP-13 expression.

METHODS

MMP-13 concentrations were measured in the supernatant of human osteoarthritis chondrocyte cultures transfected with small interfering RNA (siRNA) against the 114 genes. MMP-13 levels changed most dramatically in response to siRNA against prostaglandin EP2 receptor. The authors performed further measurements of MMP-13 production in osteoarthritis chondrocytes stimulated by the EP2 agonist butaprost in the presence or absence of interleukin-1β (IL-1β) and/or cyclooxygenase-2 (COX-2) inhibitor. They also assessed the effect of butaprost on chondrocyte viability, and investigated the involvement of the cAMP-protein kinase A (PKA) pathway on EP2 signalling using inhibitors. Cartilage-related gene expression was examined in chondrocytes treated with butaprost. The authors also investigated which E series of prostaglandin (EP) receptors are expressed in osteoarthritis cartilage.

RESULTS

MMP-13 messenger RNA expression was significantly affected by two molecules, EP2 receptor and SLC14A1, a urea transporter. In IL-1β-treated osteoarthritis chondrocytes, butaprost suppressed MMP-13 production, which was further decreased by COX-2 inhibitor. EP2 signalling downregulated MMP-13 mRNA expression via the cAMP-PKA pathway without affecting cell viability. Although EP2 signalling enhanced IL-6 expression, the expressions of several catabolic factors (MMP-1, MMP-3, MMP-13, ADAMTS5, IL-1β and tumour necrosis factor alpha) were inhibited. EP2 receptor was the major EP receptor in osteoarthritis cartilage.

CONCLUSION

The results suggest that EP2 signalling has 'anti-catabolic' effects in osteoarthritis chondrocytes.

Parathyroid hormone-related peptide regulates matrix metalloproteinase-13 gene expression in bone metastatic breast cancer cells

BACKGROUND

Breast cancer (BC) cells often metastasize to bone where they express large amounts of parathyroid hormone-related protein (PTHrP). In this study, we investigated the possibility that PTHrP may have roles in breast cancer bone metastasis independently of, or in addition to, its roles in osteoclastic function.

MATERIALS AND METHODS

A mouse model of bone metastasis was prepared by inoculating mice with suspensions of the human BC cell line MDA-MB-231 tumor cells via the left cardiac ventricle. Matrix metalloproteinase-13 (MMP-13) expression in the bone microenvironment was examined by Western blot and Real-time RT-PCR (RT-PCR) analysis, as well as by confocal microscopy.

RESULTS

The invading MDA-MB-231 cells contained conspicuous amounts of both PTHrP and MMP-13, an important matrix-degrading enzyme; and treatment of the cells in culture with exogenous PTHrP markedly stimulated MMP13 gene expression. Analysis of signaling mechanisms showed that PTHrP treatment led to rapid increases in the levels of phosphorylated protein kinase C (PKCα) and extracellular signal-regulated kinase (ERK1/2). Pharmacologic inhibition of ERK1/2 and PKC as well as of PKA activities counteracted the PTHrP-dependent stimulation of MMP13 expression. Indeed, pharmacologic activation of PKA or PKC was sufficient for stimulation of MMP13 expression.

CONCLUSION

Consistent with these findings, the inhibition of PKC prevented PTHrP-induced activation of ERK1/2, whereas 12-O-tetradecanoylphorbol-13-acetate (TPA), a stimulator of PKC, up-regulated the PTHrP-induced activation of ERK1/2. Taken together, our data indicate that the MDA-MB-231 breast cancer cells may carry out bone destruction and favor their own metastatic behavior by producing MMP-13. Given that the cells expressed PTHrP and that this factor stimulated MMP-13 expression, metastatic bone destruction may result from a PTHrP autocrine loop involving a PKC-ERK1/2 signaling pathway.

MMP13 is a potential prognostic marker for colorectal cancer

Matrix metalloproteinase 13 (MMP13), a member of the matrix metalloproteinase family, is considered to play a role in the tumor cell proliferation and invasion. The purpose of this study was to verify the expression of MMP13 in colorectal cancer (CRC) in vitro and in vivo, and subsequently analyze whether the MMP13 expression levels correlate with the clinicopathological features and prognosis of CRC patients. We assessed MMP13 mRNA expression profile in human colorectal adenocarcinoma cell lines by quantitative RT-PCR, and further verified if it was a secreted protein or not by Western blot analysis of cell culture medium. By immunohistochemical staining the immunoreactivity of MMP13 showed that MMP13 was localized in the cytoplasm of CRC cells. MMP13 mRNA expression of 80 cancerous tissues collected from UICC stage I to III CRC patients were examined by membrane array. The correlations between MMP13 mRNA expression and patients' clinicopathological features were analyzed. MMP13 was confirmed to be a secreted protein by Western blot analysis. The larger tumor size (P<0.0001), advanced clinical stage (P=0.002), tumor invasive depth (P=0.039), lymph node metastasis (P=0.001) and post-operative relapse (P<0.0001) were significantly correlated with the MMP13 mRNA overexpression. Patients with MMP13 mRNA overexpression have a higher risk of postoperative relapse (P<0.0001; OR=7.989; 95% CI, 2.607-24.481). The results of the present study highly suggest that MMP13 is a secreted protein with a significant correlation to development of postoperative relapse; hence it could be a potential prognostic marker for CRC patients.

Overexpression of MMP-13 gene in colorectal cancer with liver metastasis

Matrix metalloproteinase-7 (MMP-7), MMP-9, MMP-13, and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) are considered to have important roles in the invasiveness and outcomes of colorectal cancer (CRC). This study examined the clinicopathological significance of the relative expression of these genes in patients with colorectal cancer, especially as related to liver metastasis. The study analysed surgical specimens of cancer tissue and adjacent normal mucosa obtained from 202 patients with untreated colorectal cancer. MMP-7, MMP-9, MMP-13, TIMP-1, and beta-actin mRNA of cancer tissue and adjacent normal mucosa were measured by quantitative real-time, reverse-transcriptase polymerase chain reaction. Expression levels of MMP-7, MMP-9, MMP-13 and TIMP-1 were higher in cancer tissue than in adjacent normal mucosa. On analysis of the relations between gene expression and clinicopathological factors, MMP-13 expression was found to correlate with liver metastasis. Moreover, MMP-13 expression levels were higher in tumour tissue with liver metastasis than in that without liver metastasis. It is concluded that MMP-13 gene expression is a useful predictor of liver metastasis in patients with CRC.

Tendon degeneration is not mediated by regulation of Toll-like receptors 2 and 4 in human tenocytes

We hypothesized that expression of Toll-like receptors (TLRs) 2 and 4 by tenocytes is involved in the catabolic processes of tendon degeneration. We investigated TLR2 and TLR4 expression by tenocytes in healthy and tendinotic Achilles tendons. We also investigated whether TLR2 and TLR4 could be upregulated in tendon explants using proinflammatory cytokines interleukin (IL)-1beta and tumor necrosis factor alphpa (TNFalpha). Peroperatively harvested healthy (n = 5) and tendinotic (n = 13) Achilles tendon samples were examined by real-time RT-PCR and immunohistochemical staining for TLR2 and TLR4. In addition, the catabolic process in tendinopathy was analyzed by real-time RT-PCR for matrix metalloproteinases MMP1, MMP3, MMP9, and MMP13. Furthermore, healthy tendon explants were cultured in the presence of 20 ng/ml IL-1beta (n = 10) or 10 ng/mL TNFalpha (n = 8) for 4, 24, 48, and 72 h before analysis of TLR and MMP expression levels. Although mRNA levels for both TLR2 and TLR4 were detected in healthy and tendinotic Achilles tendons, we could not confirm expression of these receptors by immunohistochemical staining in either healthy or tendinotic tendon samples. Both receptors did not show significant transcriptional regulation in tendinopathy, although MMP3 was downregulated and MMP9 was upregulated in tendinopathy. In tendon explant cultures TLR2 mRNA was upregulated by TNFalpha (p < 0.05) and IL-1beta (not significant). TLR4 gene expression was not altered by addition of IL-1beta or TNFalpha. Tendon tissue can be stimulated to increase TLR2 gene expression by addition of catabolic factors TNFalpha or IL-1beta. However, the catabolic processes in Achilles tendinopathy cannot be attributed to regulation of TLR2 and TLR4 by tenocytes.

Co-culture of mechanically injured cartilage with joint capsule tissue alters chondrocyte expression patterns and increases ADAMTS5 production

We studied changes in chondrocyte gene expression, aggrecan degradation, and aggrecanase production and activity in normal and mechanically injured cartilage co-cultured with joint capsule tissue. Chondrocyte expression of 21 genes was measured at 1, 2, 4, 6, 12, and 24h after treatment; clustering analysis enabled identification of co-expression profiles. Aggrecan fragments retained in cartilage and released to medium and loss of cartilage sGAG were quantified. Increased expression of MMP-13 and ADAMTS4 clustered with effects of co-culture, while increased expression of ADAMTS5, MMP-3, TGF-beta, c-fos, c-jun clustered with cartilage injury. ADAMTS5 protein within cartilage (immunohistochemistry) increased following injury and with co-culture. Cartilage sGAG decreased over 16-days, most severely following injury plus co-culture. Cartilage aggrecan was cleaved at aggrecanase sites in the interglobular and C-terminal domains, resulting in loss of the G3 domain, especially after injury plus co-culture. Together, these results support the hypothesis that interactions between injured cartilage and other joint tissues are important in matrix catabolism after joint injury.

Osteocalcin attenuates T3- and increases vitamin D3-induced expression of MMP-13 in mouse osteoblasts

Osteocalcin (OCN), the most abundant non-collagenous protein of the bone matrix, whose function is not fully understood, was recently suggested to act as endocrine factor regulating energy metabolism. Besides OCN, osteoblasts also express MMP-13, a matrix metallo-proteinase important for bone development and remodeling. Although differentially, both genes are regulated by 1,25-dihydroxy vitamin D3 (1,25D3) and T3, important hormones for bone metabolism. In mouse osteoblasts with a distinct differentiation status, T3 increases the expression of both proteins. By contrast, 1,25D3 stimulates the expression of MMP-13 but inhibits the expression of OCN in these cells. In humans, however, 1,25D3 upregulates both genes while T3 inhibits the OCN expression. Using northern blot hybridization we studied gene expression in the mouse osteoblastic cell line MC3T3-E1. We show that MMP-13 expression was strongly increased by T3 when the stimulation of OCN was low and, inversely, that the MMP-13 increase was low when T3 strongly stimulated the OCN expression. These findings suggest an interrelationship between OCN and MMP-13 expression. In fact, we observed that externally added OCN attenuated the T3 induced MMP-13 expression dose dependently and, furthermore, increased the 1,25D3 stimulated MMP-13 expression. Using a protein kinase A inhibitor we were able to show that this inhibitor mimics the effect of OCN suggesting a PKA dependent pathway to be involved in this regulatory process. We therefore hypothesize that OCN is a modulator of the hormonally regulated MMP-13 expression.

Matrix metalloproteinase 13 is induced in fibroblasts in polyomavirus middle T antigen-driven mammary carcinoma without influencing tumor progression

Matrix metalloproteinase (MMP) 13 (collagenase 3) is an extracellular matrix remodeling enzyme that is induced in myofibroblasts during the earliest invasive stages of human breast carcinoma, suggesting that it is involved in tumor progression. During progression of mammary carcinomas in the polyoma virus middle T oncogene mouse model (MMTV-PyMT), Mmp13 mRNA was strongly upregulated concurrently with the transition to invasive and metastatic carcinomas. As in human tumors, Mmp13 mRNA was found in myofibroblasts of invasive grade II and III carcinomas, but not in benign grade I and II mammary intraepithelial neoplasias. To determine if MMP13 plays a role in tumor progression, we crossed MMTV-PyMT mice with Mmp13 deficient mice. The absence of MMP13 did not influence tumor growth, vascularization, progression to more advanced tumor stages, or metastasis to the lungs, and the absence of MMP13 was not compensated for by expression of other MMPs or tissue inhibitor of metalloproteinases. However, an increased fraction of thin collagen fibrils was identified in MMTV-PyMT;Mmp13(-/-) compared to MMTV-PyMT;Mmp13(+/+) tumors, showing that collagen metabolism was altered in the absence of MMP13. We conclude that the expression pattern of Mmp13 mRNA in myofibroblasts of invasive carcinomas in the MMTV-PyMT breast cancer model recapitulates the expression pattern observed in human breast cancer. Our results suggest that MMP13 is a marker of carcinoma-associated myofibroblasts of invasive carcinoma, even though it does not make a major contribution to tumor progression in the MMTV-PyMT breast cancer model.

Taurine chloramine differentially inhibits matrix metalloproteinase 1 and 13 synthesis in interleukin-1beta stimulated fibroblast-like synoviocytes

It has been suggested that taurine chloramine (TauCl) plays an important role in the downregulation of proinflammatory mediators. However, little is known about its effect on the expression of matrix metalloproteinases (MMPs). In this study, we investigated the effects of TauCl on synovial expression of MMPs. The effects of TauCl on MMP expression in IL-1β stimulated fibroblast-like synoviocytes (FLSs) were studied using the following techniques. Real-time PCR and semi-quantitative PCR were employed to analyze the mRNA expression of MMPs. ELISA was used to determine protein levels of MMPs. Western blot analyses were performed to analyze the mitogen-activated protein kinase and inhibitor of nuclear factor-κB (IκB) kinase signalling pathways. Finally, electrophoretic mobility shift assay and immunohistochemistry were used to assess localization of transcription factors. IL-1β increased the transcriptional and translational levels of MMP-1 and MMP-13 in rheumatoid arthritis FLSs, whereas the levels of MMP-2 and MMP-9 were unaffected. TauCl at a concentration of 400 to 600 μmol/l greatly inhibited the transcriptional and translational expression of MMP-13, but the expression of MMP-1 was significantly inhibited at 800 μmol/l. At a concentration of 600 μmol/l, TauCl did not significantly inhibit phosphorylation of mitogen-activated protein kinase or IκB degradation in IL-1β stimulated rheumatoid arthritis FLSs. The degradation of IκB was significantly inhibited at a TauCl concentration of 800 μmol/l. The inhibitory effect of TauCl on IκB degradation was confirmed by electrophoretic mobility shift assay and immunochemical staining for localization of nuclear factor-κB. TauCl differentially inhibits the expression of MMP-1 and MMP-13, and inhibits expression of MMP-1 primarily through the inhibition of IκB degradation, whereas it inhibits expression of MMP-13 through signalling pathways other than the IκB pathway.

Nmp4/CIZ contributes to fluid shear stress induced MMP-13 gene induction in osteoblasts

The expression of matrix metalloproteinase-13 (MMP-13), involved in bone turnover, is elevated in stretched MC3T3-E1 osteoblast-like cells. Strain-mediated forces impact bone remodeling due in large part to the movement of fluid through the canalicular-lacunar network. The resulting fluid shear stress (FSS) over the surface membranes of bone cells initiates bone remodeling. Although the nuclear events mediating putative FSS-induced changes in osteoblast MMP-13 transcription are unknown, previous studies with bone cells suggest an overlap between osteoblast FSS- and PTH-induced signal response pathways. MMP-13 PTH response is regulated by a 110 bp 5' regulatory region, conserved across the mouse, rat, and human genes, that supports the binding of numerous transcription factors including Runx2, c-fos/c-jun, Ets-1, and nuclear matrix protein 4/cas interacting zinc finger protein (Nmp4/CIZ) a nucleocytoplasmic shuttling trans-acting protein that attenuates PTH-driven transcription. Nmp4/CIZ also binds p130(cas), an adaptor protein implicated in mechanotransduction. Here we sought to determine whether Nmp4/CIZ contributes to FSS-induced changes in MMP-13 transcription. FSS (12 dynes/cm(2), 3-5 h) increased MMP-13 promoter-reporter activity approximately two-fold in MC3T3-E1 osteoblast-like cells attended by a comparable increase in mRNA expression. This was accompanied by a decrease in Nmp4/CIZ binding to its cis-element within the PTH response region, the mutation of which abrogated the MMP-13 response to FSS. Interestingly, FSS enhanced Nmp4/CIZ promoter activity and induced p130(cas) nuclear translocation. We conclude that the PTH regulatory region of MMP-13 also contributes to FSS response and that Nmp4/CIZ plays similar but distinct roles in mediating hormone- and FSS-driven induction of MMP-13 in bone cells.

Interface membrane fibroblasts around aseptically loosened endoprostheses express MMP-13

The objective of this article was to assess whether matrix metalloproteinase-13 (MMP-13) is produced by cells of the peri-implant interface tissues and to further characterize these cells. Tissue specimens were collected from the bone-prosthesis interface at the time of revision surgery of clinically loosened hip and knee arthroplasties (n = 27). Synovial tissues from osteoarthritic patients and young patients with mild joint deformity were used as controls (n = 6). Tissue samples were fixed in 4% PFA, decalcified with EDTA, and embedded in paraffin. Sections (4 microm) were stained with hematoxylin/eosin and for the osteoclastic marker enzyme tartrate resistant acid phosphatase. Monocytes/macrophages were characterized with a monoclonal antibody against CD68 and mRNAs encoding MMP-13 and alpha(1) collagen I (COL1A1) were detected by in situ hybridization. Cells expressing transcripts encoding MMP-13 were found in 70% of the interface tissues. These cells colocalized with a cell population expressing COL1A1 mRNA, and were fibroblastic in appearance. MMP-13 expressing cells were found in the close vicinity of osteoclasts and multinuclear giant cells. No signals for transcripts encoding MMP-13 were detected in multinuclear giant cells or in osteoclasts. Control tissues were negative for transcripts encoding MMP-13 mRNA. Fibroblasts of the interface from aseptically loosened endoprostheses selectively express MMP-13. By the expression and the release of MMP-13, these fibroblastic cells may contribute to the local degradation of the extracellular matrix and to bone resorption.

Accelerated cellular senescence in degenerate intervertebral discs: a possible role in the pathogenesis of intervertebral disc degeneration

Current evidence implicates intervertebral disc degeneration as a major cause of low back pain, although its pathogenesis is poorly understood. Numerous characteristic features of disc degeneration mimic those seen during ageing but appear to occur at an accelerated rate. We hypothesised that this is due to accelerated cellular senescence, which causes fundamental changes in the ability of disc cells to maintain the intervertebral disc (IVD) matrix, thus leading to IVD degeneration. Cells isolated from non-degenerate and degenerate human tissue were assessed for mean telomere length, senescence-associated β-galactosidase (SA-β-gal), and replicative potential. Expression of P16^INK4A (increased in cellular senescence) was also investigated in IVD tissue by means of immunohistochemistry. RNA from tissue and cultured cells was used for real-time polymerase chain reaction analysis for matrix metalloproteinase-13, ADAMTS 5 (a disintegrin and metalloprotease with thrombospondin motifs 5), and P16^INK4A. Mean telomere length decreased with age in cells from non-degenerate tissue and also decreased with progressive stages of degeneration. In non-degenerate discs, there was an age-related increase in cellular expression of P16^INK4A. Cells from degenerate discs (even from young patients) exhibited increased expression of P16^INK4A, increased SA-β-gal staining, and a decrease in replicative potential. Importantly, there was a positive correlation between P16^INK4A and matrix-degrading enzyme gene expression. Our findings indicate that disc cell senescence occurs in vivo and is accelerated in IVD degeneration. Furthermore, the senescent phenotype is associated with increased catabolism, implicating cellular senescence in the pathogenesis of IVD degeneration.

Novel p38 MAP kinase inhibitor R-130823 suppresses IL-6, IL-8 and MMP-13 production in spheroid culture of human synovial sarcoma cell line SW 982

Synovial hyperplasia is a hallmark of rheumatoid arthritis (RA) and is regarded as a major destructive element of articular bone and cartilage. This pathological process is accompanied by the production of proinflammatory cytokines, prostaglandin E(2) (PGE(2)), and matrix metalloproteinases (MMPs) in synoviocytes. We studied the spontaneous production of these substances in RA synoviocytes in spheroid culture. Synovial sarcoma cell line SW 982 formed a single spheroid in non-adherent culture plates. It produced interleukin (IL)-1beta, IL-6, IL-8, PGE(2), MMP-2 and MMP-13. Neither the addition of integrin antagonizing oligopeptide (GRGDSP) nor that of vitronectin receptor inhibitor SB-265123 to the culture inhibited any production. Phosphorylation of p38 mitogen-activated protein (MAP) kinase was observed during the culture. A novel p38 MAP kinase inhibitor, R-130823, inhibited the release of IL-6, IL-8 and MMP-13 in a concentration-dependent manner, but not that of IL-1beta or MMP-2. Real-time RT-PCR analysis demonstrated that IL-6, IL-8 and MMP-13 were inhibited at the transcriptional level. R-130823 did not affect the production of PGE(2) in spheroid culture, while the addition of R-130823 suppressed IL-1beta-induced PGE(2) synthesis in monolayer culture of SW 982 cells. The results suggest that spheroid culture induced proinflammatory factors and MMPs in signaling pathways both dependent and independent of p38 MAP kinase.

Interleukin-4 antagonizes oncostatin M and transforming growth factor beta-induced responses in articular chondrocytes

Oncostatin M (OSM) stimulates cartilage degradation in rheumatoid arthritis (RA) by inducing matrix metalloproteinases (MMPs) and aggrecanases (ADAMTS; a disintegrin and metalloproteinase with thrombospondin motif). Transforming growth factor beta (TGF-beta1) induces cartilage repair in joints but in excessive amounts, promotes inflammation. OSM and TGF-beta1 also induce tissue inhibitor of metalloproteinase-3 (TIMP-3), an important natural inhibitor of MMPs, aggrecanases, and tumor necrosis factor alpha converting enzyme (TACE), the principal proteases involved in arthritic inflammation and cartilage degradation. We studied cartilage protective mechanisms of the antiinflammatory cytokine, interleukin-4 (IL-4). IL-4 strongly (MMP-13 and TIMP-3) or minimally (ADAMTS-4) suppressed OSM-induced gene expression in chondrocytes. IL-4 did not affect OSM-stimulated phosphorylation of extracellular signal-regulated kinases (ERKs), protein 38 (p38), c-Jun N-terminal kinase (JNK) and Stat1. Lack of additional suppression with their inhibitors suggested that MMP-13, ADAMTS-4, and TIMP-3 inhibition was independent of these mediators. IL-4 also downregulated TGF-beta1-induced TIMP-3 gene expression, Smad2, and JNK phosphorylation. Additional suppression of TIMP-3 RNA by JNK inhibitor suggests JNK implication. The cartilage protective effects of IL-4 in animal models of arthritis may be due to its inhibition of MMPs and ADAMTS-4 expression. However, suppression of TIMP-3 suggests caution for using IL-4 as a cartilage protective therapy.

A metalloproteinase-13 polymorphism affecting its gene expression is associated with advanced stages of oral cancer

BACKGROUND

Based on the known contribution of other metalloproteinases to the development of oral cancer, this study investigated the possible association of the -77A/G polymorphism in the matrix metalloproteinase-13 (MMP-13) gene with the risk of oral cancer.

PATIENTS AND METHODS

The polymorphism -77A/G, which affects gene transcription, was examined in DNA samples of 161 patients with oral squamous cell carcinoma and 97 healthy controls of comparable ethnicity, age and gender.

RESULTS

The detected allele and carrier frequency for the high expression A allele in the patient group were not significantly increased in comparison to that of the control group (70.8% versus 65.5%, and 95% versus 89.7%, respectively). The same pattern was observed between controls and patients or subgroups of patients in regard to family history of cancer, smoking and heavy alcohol consumption. Only in the subgroup of patients with advanced stages of cancer was the allele frequency for the high expression A allele significantly increased compared to controls (p = 0.038). In the same subgroup AA genotypes had a borderline significant difference from controls (p = 0.059).

CONCLUSION

MMP-13 gene expression-related polymorphism is associated with risk for the highly aggressive form of oral cancer. The high expression A allele of the -77A/G polymorphism seems to be a prognostic factor for tumor progression.

MMP-13 and p53 in the progression of malignant peripheral nerve sheath tumors

Malignant peripheral nerve sheath tumors (MPNST) are sarcomas with poor prognosis and limited treatment options. Factors contributing to tumor progression are largely unknown. We therefore examined MPNST from 22 neurofibromatosis type 1 (NF1) patients, 14 non-NF1 patients, and 14 neurofibroma patients for matrix metalloproteinase 13 (MMP-13) expression. Because wild-type and mutant p53 were shown to differentially regulate MMP-13 expression, TP53 status and protein levels were also determined. MMP-13 expression was detected in 58% of MPNST and was significantly associated with recurrent MPNST (P = .019). p53 was observed in 78% of MPNST and was found to be strongly associated with MMP-13 expression (P = .005). In contrast, 14 neurofibromas lacked MMP-13 and p53 expressions. TP53 mutations were found in only 11% of MPNST and were associated with high tumor grades (P = .029). No significant association between mutant TP53 and MMP-13 was observed, indicating that other factors drive MMP-13 expression in MPNST. The presence of metastasis was linked to p53Pro(72) polymorphism (P = .041) and shorter survival. In summary, our data suggest that MMP-13 expression in nerve sheath tumors is coupled with malignant progression. Therefore, MMP-13 may serve as a marker for progression and as a therapeutic target.

Matrix metalloproteinase-13 is required for zebra fish (Danio rerio) development and is a target for glucocorticoids

Matrix metalloproteinases (MMPs) are endopeptidases that degrade the proteins of the extracellular matrix (ECM). Expression and activity of the MMPs are essential for embryogenesis, where MMPs participate in the normal ECM remodeling that occurs during tissue morphogenesis and development. Studies have demonstrated that MMP gene expression is inhibited by glucocorticoids in mammalian cell culture systems and that exposure to glucocorticoids causes developmental abnormalities in several species. Therefore, we proposed that glucocorticoids impede normal development through alteration of MMP expression. Zebra fish (Danio rerio) were used as a model to study MMP-13 expression both during normal embryogenesis and following acute exposure to two glucocorticoids, dexamethasone, and hydrocortisone. MMP-13 is one of three collagenases identified in vertebrates that catalyzes the degradation of type I collagens at neutral pH. MMP-13 expression varied during zebra fish development, with peak expression at 48 h post-fertilization (hpf). Morpholino knockdown studies showed that MMP-13 expression is necessary for normal zebra fish embryogenesis. Acute exposure to dexamethasone and hydrocortisone resulted in abnormal zebra fish development including craniofacial abnormalities, altered somitogenesis, blood pooling and pericardial and yolk sac edema as well as increased MMP-13 mRNA and activity at 72 hpf. In situ hybridization experiments were used to confirm the increase in MMP-13 expression following glucocorticoid treatment and showed elevated MMP-13 expression in the rostral trunk, brain, eye, heart, and anterior kidney of treated embryos. These data demonstrate that normal zebra fish embryogenesis requires MMP-13 and that dexamethasone and hydrocortisone modulate the expression of this gene, leading to increased activity and potentially contributing to subsequent dysmorphogenesis.

Basic fibroblast growth factor activates the MAPK and NFkappaB pathways that converge on Elk-1 to control production of matrix metalloproteinase-13 by human adult articular chondrocytes

The pathology of joint destruction is associated with elevated production of basic fibroblast growth factor (bFGF) and matrix metalloproteinase-13 (MMP-13). In osteoarthritic joint disease, expression of bFGF and MMP-13 in chondrocytes and their release into the synovial fluid are significantly increased. We have previously found that the capacity for cartilage repair in human adult articular chondrocytes is severely compromised by minimal exposure to bFGF because bFGF reduces responsiveness to bone morphogenetic protein-7 and insulin-like growth factor-1 and induces MMP-13 through protein kinase Cdelta-dependent activation of multiple mitogen-activated protein kinase (MAPK) signaling pathways. Here we show using biochemical and molecular approaches that transcription factor Elk-1, a direct downstream target of MAPK, is a critical transcriptional activator of of MMP-13 by bFGF in human articular chondrocytes. We also provide evidence that Elk-1 is a direct target of NFkappaB and induces MMP-13 expression upon activation of the NFkappaB signaling pathway. Taken together, our results suggest that elevated expression of MMP-13 occurs through Elk-1 activation of both MAPK and NFkappaB signaling pathways, thus revealing a two-pronged biological mechanism by which bFGF controls the production of catabolic enzymes that are associated with excessive degradation of the cartilage matrix in degenerative joint diseases such as osteoarthritis.