IL-1ß promotes ADAMTS enzyme-mediated aggrecan degradation through NF-κB in human intervertebral disc.

BACKGROUND: The purpose of this study is to investigate IL-1ß regulation of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS-4 and ADAMTS-5) expression through nuclear factor kappa B (NF-κB) in human nucleus pulposus (NP) cells. METHODS: qRT-PCR and Western blot were used to measure ADAMTS expression. Transfections and gene silencing were used to determine the role of NF-κB on cytokine-mediated ADAMTS expression and its role in aggrecan degradation. RESULTS: IL-1ß increased ADAMTS expression in NP cells. Treatment with NF-κB inhibitors abolished the inductive effect of the cytokines on ADAMTS expression. Silencing of p65 confirmed their role in IL-1ß-dependent ADAMTS-4 and ADAMTS-5 expression and aggrecan degradation. CONCLUSIONS: By controlling the activation of NF-κB signaling, IL-1ß modulates the expression of ADAMTS in NP cells. To our knowledge, this is the first study that shows the contribution of both ADAMTS-4 and ADAMTS-5 to aggrecan degradation in human NP cells.

ADAMTS-4 and ADAMTS-5 expression in human temporomandibular joint discs with internal derangement, correlates with degeneration.

Temporomandibular joint (TMJ) internal derangement (ID) is one of the most common form of temporomandibular disorders. There is evidence showing the increased expression of matrix metalloproteinases (MMPs) in the cells from degenerated TMJ disc. ADAMTS are a large family of metalloproteases which are responsible for proteoglycans degradation. The present study aimed to evaluate ADAMTS-4 and ADAMTS-5 immunohistochemical expression in human TMJ discs from patients affected by ID, and to find out if there is any correlation with the degree of histopathological changes. Eighteen temporomandibular displaced disc specimens and sixteen TMJ disc control were used for the present study. Specimens were immunohistochemically processed and ADAMTS-4 and ADAMTS-5 expression were obtained respectively for the anterior (AB), intermediate (IB) and posterior (PB) bands and compared to the histopathological degeneration score (HDS). Immunoreactivity for ADAMTS-4 and -5, was observed in both not degenerated and degenerated human TMJ discs. Both the percentage of ADAMTS-4 and -5 immunostained cells (ES) and the intensity of staining (IS) were significantly greater in affected specimens compared with those in control discs. The ADAMTS-5 ES and IS of the 3 bands of the disc correlated to the TMJ disc HDS (0.001 < P < 0.05), on the other hand only AB and IB, ADAMTS-4 immunostaining scores correlated to HDS. According to these findings it can be assumed in that the more histopathological changes in the disc are detected, the higher levels of ADAMTS are produced. This in turn can lead to ECM breakdown and in turn to a more advanced disc displacement.

Early induction of ADAMTS 1, -4, -5 and -9 in IL-stimulated mouse astrocytes.

AIM: Astrocytes and extracellular matrix molecules have important roles in regulating synaptic functions between neurons in the central nervous system. However, under pathological conditions, these constituents are activated to form glial scar that is thought to be harmful for neuronal regeneration. The aim of this study was to evaluate the expression pattern of ADAMTS1, -4, -5 and -9 in IL-1 stimulated astrocyte cultures obtained from postnatal day zero mouse brains. MATERIAL AND METHODS: Real time PCR analyses were performed. RESULTS: An overexpression of ADAMTS1, -4, -5 and -9 at the 3-h time point after IL-1 stimulation was found. IL-1 stimulation induced aggrecaneses and this effect was time dependent. Maximum increase was detected at 3-h (six fold increase). Interestingly the expression of ADAMTS1 and -4 appeared to be at the highest expression level but the ADAMTS5 and ADAMTS9 expression level was much weaker (three times and two times respectively). CONCLUSION: To the best of our knowledge, this is the first report demonstrating induction of ADAMTS in IL-1 induced astrocytes. Aggrecanases may play a role in tissue destruction in the progression of central nervous system (CNS) injury and they are differentially expressed in mouse CNS, suggesting a critical role in the pathogenesis of CNS injury. This can be a very crucial aetiologic factor for some neuropsychiatric disorders.

Differential expression patterns of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) -1, -4, -5, and -14 in human placenta and gestational trophoblastic diseases.

CONTEXT: The ability of intermediate trophoblasts to invade maternal tissue during placentation depends on how well they can degrade the extracellular matrix. Invasion into the extracellular matrix requires many complex proteases. A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) is a novel family of secreted metalloproteinases. The ADAMTS-1, -4, -5, and -14 subtypes are known to be expressed in human placenta, but little is understood about their expression patterns. OBJECTIVE: To examine the expression patterns of ADAMTS-1, -4, -5, and -14 in specific human placenta cell types during gestation and in gestational trophoblastic diseases. DESIGN: Placental tissues were obtained from 25 pregnant women and 21 cases of gestational trophoblastic diseases (10 early complete moles, 3 placental site trophoblastic tumors, 4 invasive moles, and 4 choriocarcinomas). The expression of the 4 ADAMTS was analyzed by immunohistochemistry. RESULTS: ADAMTS-1, -4, -5, and -14 were differentially expressed by the human placenta throughout gestation in a time-specific and cell type-specific manner, as well as in gestational trophoblastic diseases. ADAMTS-1 showed gradually strong staining intensity in gestational trophoblastic diseases according to the invasive potential but showed consistent strong intensity throughout normal placenta. ADAMTS-4 and ADAMTS-5 exhibited higher and restricted expression in first-trimester intermediate trophoblasts. They also exhibited comparably strong expression in gestational trophoblastic diseases. However, ADAMTS-14 expression remained unchanged throughout gestation. CONCLUSIONS: The restricted expression pattern of ADAMTS-4 and ADAMTS-5 and their increased expression in gestational trophoblastic diseases suggest that these 2 ADAMTS subtypes are associated with a biological phenotype of trophoblasts involved in human placentation and the development of gestational trophoblastic diseases.

IL-6 upregulates a disintegrin and metalloproteinase with thrombospondin motifs 2 (ADAMTS-2) in human osteosarcoma cells mediated by JNK pathway.

ADAMTS-2 and ADAMTS-3 (a disintegrin and metalloproteinase with thrombospondin type 1 motif 2) belong to the procollagen aminoproteinase subfamily of ADAMTS proteases. They play crucial roles in the collagen metabolism. To understand the regulation of ADAMTS-2 gene expression in osteoblastic cells, we have cloned a functional 760 bp of human ADAMTS-2 promoter. Sequence analysis of the ADAMTS-2 promoter region showed the absence of a TATA box, but identified a GC box, a CpG island, several GAGA boxes and several transcriptional factor binding sites, which may be valuable in the regulation of ADAMTS-2 transcription. We also elucidated that Interleukin 6 (IL-6) increases ADAMTS-2 and ADAMTS-3 mRNA and protein levels in different osteosarcoma cell lines namely, MG-63 and Saos-2. IL-6 also increases the transcriptional activation of the ADAMTS-2 gene promoter. Pathway inhibition studies revealed that ADAMTS-2 upregulation by IL-6 was mediated by JNK pathway.

Gene expression profiling of craniofacial fibrous dysplasia reveals ADAMTS2 overexpression as a potential marker.

Fibrous dysplasia (FD) as an abnormal bone growth is one of the common fibro-osseous leasions (FOL) in oral and maxillofacial region, however, its etiology still remains unclear. Here, we performed gene expression profiling of FD using microarray analysis to explore the key molecule events in FD development, and develop potential diagnostic markers or therapeutic targets for FD. We found that 1,881 genes exhibited differential expression with more than two-fold changes in FD compared to normal bone tissues, including 1,200 upregulated genes and 681 downregulated genes. Pathway analysis indicated that obviously activated pathways are Ribosome and ECM-receptor interaction pathways; downregulated pathways are "Hepatitis C" and "cancer" signaling pathways. We further validated the expression of ADAMTS2, one of most differentiated expressed genes, by Immunohistochemistry (IHC) in 40 of FD cases. Results showed that ADAMTS2 was significantly overexpressed in FD tissues, but rarely expressed in normal bone tissues, suggesting that ADAMTS2 could be a potential biomarker for FD. Thus, this study uncovered differentially expressed candidate genes in FD, which provides pilot data for understanding FD pathogenesis, and developing novel biomarkers for diagnosis and targeting of FD.

Regulation of ADAMTS-1, -4 and -5 expression in human macrophages: differential regulation by key cytokines implicated in atherosclerosis and novel synergism between TL1A and IL-17.

Atherosclerosis is an inflammatory disease of the vasculature regulated by cytokines. Macrophages play a crucial role at all stages of this disease, including regulation of foam cell formation, the inflammatory response and stability of atherosclerotic plaques. For example, matrix metalloproteinases produced by macrophages play an important role in modulating plaque stability. More recently, the ADAMTS proteases, which are known to play a key role in the control of cartilage degradation during arthritis, have been found to be expressed in atherosclerotic lesions and suggested to have potentially important functions in the control of plaque stability. Unfortunately, the action of cytokines on the expression of ADAMTS family in macrophages is poorly understood. We have investigated the effect of classical cytokines (IFN-γ and TGF-ß) and those that have been recently identified (TL1A and IL-17) on the expression of ADAMTS-1, -4 and -5 in human macrophages. The expression of all three ADAMTS members was induced during differentiation of monocytes into macrophages. TGF-ß had a differential action with induction of ADAMTS-1 and -5 expression and attenuation in the levels of ADAMTS-4. In contrast, IFN-γ suppressed the expression of ADAMTS-1 without having an effect on ADAMTS-4 and -5. Although TL-1A or IL-17A alone had little effect on the expression of all the members, they induced their expression synergistically when present together. These studies provide new insight into the regulation of key ADAMTS family members in human macrophages by major cytokines in relation to atherosclerosis.

Cellular dissection of the spinal cord motor column by BAC transgenesis and gene trapping in zebrafish.

Bacterial artificial chromosome (BAC) transgenesis and gene/enhancer trapping are effective approaches for identification of genetically defined neuronal populations in the central nervous system (CNS). Here, we applied these techniques to zebrafish (Danio rerio) in order to obtain insights into the cellular architecture of the axial motor column in vertebrates. First, by using the BAC for the Mnx class homeodomain protein gene mnr2b/mnx2b, we established the mnGFF7 transgenic line expressing the Gal4FF transcriptional activator in a large part of the motor column. Single cell labeling of Gal4FF-expressing cells in the mnGFF7 line enabled a detailed investigation of the morphological characteristics of individual spinal motoneurons, as well as the overall organization of the motor column in a spinal segment. Secondly, from a large-scale gene trap screen, we identified transgenic lines that marked discrete subpopulations of spinal motoneurons with Gal4FF. Molecular characterization of these lines led to the identification of the ADAMTS3 gene, which encodes an evolutionarily conserved ADAMTS family of peptidases and is dynamically expressed in the ventral spinal cord. The transgenic fish established here, along with the identified gene, should facilitate an understanding of the cellular and molecular architecture of the spinal cord motor column and its connection to muscles in vertebrates.

Inflammatory cytokines associated with degenerative disc disease control aggrecanase-1 (ADAMTS-4) expression in nucleus pulposus cells through MAPK and NF-κB.

We investigated TNF-α and IL-1ß regulation of ADAMTS-4 expression in nucleus pulposus (NP) cells and its role in aggrecan degradation. Real-time quantitative RT-PCR, Western blotting, and transient transfections with rat NP cells and lentiviral silencing with human NP cells were performed to determine the roles of MAPK and NF-κB in cytokine-mediated ADAMTS-4 expression and function. ADAMTS4 expression and promoter activity increased in NP cells after TNF-α and IL-1ß treatment. Treatment of cells with MAPK and NF-κB inhibitors abolished the inductive effect of the cytokines on ADAMTS4 mRNA and protein expression. Although ERK1, p38α, p38ß2, and p38γ were involved in induction, ERK2 and p38δ played no role in TNF-α-dependent promoter activity. The inductive effect of p65 on ADAMTS4 promoter was confirmed through gain and loss-of-function studies. Cotransfection of p50 completely blocked p65-mediated induction. Lentiviral transduction with shRNA plasmids shp65, shp52, shIKK-α, and shIKK-ß significantly decreased TNF-α-dependent increase in ADAMTS-4 and -5 levels and aggrecan degradation. Silencing of either ADAMTS-4 or -5 resulted in reduction in TNF-α-dependent aggrecan degradation in NP cells. By controlling activation of MAPK and NF-κB signaling, TNF-α and IL-1ß modulate expression of ADAMTS-4 in NP cells. To our knowledge, this is the first study to show nonredundant contribution of both ADAMTS-4 and ADAMTS-5 to aggrecan degradation in human NP cells in vitro.

Transcript levels of major MMPs and ADAMTS-4 in relation to the clinicopathological profile of patients with tuberculous intervertebral discs and healthy controls.

OBJECTIVES: The purpose of the present study was to simultaneously examine the transcript levels of a large number of MMPs (-3, -8, -9, -13 and -14) and ADAMTS-4 and to investigate their correlation with the clinicopathological profile of patients suffering from tuberculous intervertebral discs. DESIGN AND METHODS: Clinical data were collected from 130 patients participating in the study from March 2011 to April 2012. mRNA expression levels were determined by means of the real-time polymerase chain reaction in 60 tuberculous (TB), 60 herniated, and 10 control intervertebral disc (ID) specimens. RESULTS: MMP-8, -9, -13, and -14 that showed a stronger expression in spinal TB disc tissue compared to normal ID tissue (P<0.05). Our results showed multiple positive correlations among MMP-8, -9, and -13 mRNA in TB samples. Smoking habits were found to significantly up-regulate the transcript levels of MMP-3 and -13 (P<0.05). Pain intensity, duration of symptoms, CRP, and ESR significantly affected the transcript levels of several MMPs (P<0.05). CONCLUSIONS: The MMPs may drive extracellular matrix destruction in spinal tuberculosis intervertebral discs. The experimental data imply a synergistic effect on the activity of these MMPs in spinal tuberculosis intervertebral discs. Furthermore, the experimental data suggest that smoking plays an unfavourable role in the prognosis of spinal tuberculosis intervertebral discs. Moreover, pain intensity, duration of symptoms, CRP, and ESR may affect the process of extracellular matrix destruction by increasing the expression of MMPs in spinal tuberculosis intervertebral disc samples.

Mechanisms involved in suppression of ADAMTS4 expression in synoviocytes by high molecular weight hyaluronic acid.

Aggrecan degradation is considered to play a key role in the progression of osteoarthritis (OA). Aggrecanases are members of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) family, and degrade aggrecan in OA cartilage. The aim of this study was to clarify the mechanisms of expression of ADAMTS4 induced by IL-1ß in human fibroblast-like synoviocyte (HFLS) cells by high molecular weight hyaluronan (HMW-HA), a therapeutic agent used for OA. Monolayer cultures of HFLS cells were incubated with IL-1ß and HMW-HA. In some experiments, cells were pretreated with the CD44 function-blocking monoclonal antibody or inhibitors of signaling pathways prior to addition of IL-1ß and HMW-HA. The expressions of ADAMTS4 mRNA and protein were monitored using real-time RT-PCR, Western blotting, and immunofluorescence microscopy. To further determine the role of HMW-HA in IL-1ß-induced ADAMTS4 expression, activation of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), c-jun NH2-terminal kinase (JNK), Akt, and NF-κB were analyzed by Western blotting. HMW-HA suppressed ADAMTS4 mRNA and protein expressions induced by IL-1ß. Pretreatment with the anti-CD44 monoclonal antibody recovered the inhibitory effect of HMW-HA on expression of ADAMTS4 mRNA induced by IL-1ß. Western blotting analysis revealed that IL-1ß-induced phosphorylation of p38 MAPK and JNK protein were diminished by HMW-HA. Furthermore, inhibition of the p38 MAPK and JNK pathways by chemical inhibitors suppressed ADAMTS4 mRNA expression stimulated by IL-1ß. These results suggest that HMW-HA plays an important role as a regulatory factor in synovial tissue inflammation.

MicroRNA-125b regulates the expression of aggrecanase-1 (ADAMTS-4) in human osteoarthritic chondrocytes.

INTRODUCTION: Increased expression of aggrecanase-1 (ADAMTS-4) has emerged as an important factor in osteoarthritis (OA) and other joint diseases. This study aimed to determine whether the expression of ADAMTS-4 in human chondrocytes is regulated by miRNA. METHODS: MiRNA targets were identified using bioinformatics. Chondrocytes were isolated from knee cartilage and treated with interleukin-1 beta (IL-1ß). Gene expression was quantified using TaqMan assays and protein production was determined by immunoblotting. Luciferase reporter assay was used to verify interaction between miRNA and target messenger RNA (mRNA). RESULTS: In silico analysis predicted putative target sequence of miR-125b on ADAMTS-4. MiR-125b was expressed in both normal and OA chondrocytes, with significantly lower expression in OA chondrocytes than in normal chondrocytes. Furthermore, IL-1ß-induced upregulation of ADAMTS-4 was suppressed by overexpression of miR-125b in human OA chondrocytes. In the luciferase reporter assay, mutation of the putative miR-125b binding site in the ADAMTS-4 3'UTR abrogated the suppressive effect of miR125. CONCLUSIONS: Our results indicate that miR-125b plays an important role in regulating the expression of ADAMTS-4 in human chondrocytes and this identifies miR-125b as a novel therapeutic target in OA.

Genotoxic stress accelerates age-associated degenerative changes in intervertebral discs.

Intervertebral disc degeneration (IDD) is the leading cause of debilitating spinal disorders such as chronic lower back pain. Aging is the greatest risk factor for IDD. Previously, we demonstrated IDD in a murine model of a progeroid syndrome caused by reduced expression of a key DNA repair enzyme. This led us to hypothesize that DNA damage promotes IDD. To test our hypothesis, we chronically exposed adult wild-type (Wt) and DNA repair-deficient Ercc1(-/Δ) mice to the cancer therapeutic agent mechlorethamine (MEC) or ionization radiation (IR) to induce DNA damage and measured the impact on disc structure. Proteoglycan, a major structural matrix constituent of the disc, was reduced 3-5× in the discs of MEC- and IR-exposed animals compared to untreated controls. Expression of the protease ADAMTS4 and aggrecan proteolytic fragments was significantly increased. Additionally, new PG synthesis was reduced 2-3× in MEC- and IR-treated discs compared to untreated controls. Both cellular senescence and apoptosis were increased in discs of treated animals. The effects were more severe in the DNA repair-deficient Ercc1(-/Δ) mice than in Wt littermates. Local irradiation of the vertebra in Wt mice elicited a similar reduction in PG. These data demonstrate that genotoxic stress drives degenerative changes associated with IDD.

Evaluation of the inflammatory response in experimentally induced synovitis in the horse: a comparison of recombinant equine interleukin 1 beta and lipopolysaccharide.

OBJECTIVE: To compare two transient models of synovitis-osteoarthritis (OA) in horses by characterizing biological changes in synovial fluid and joint tissue. METHOD: Twelve skeletally mature mares were utilized in a block design. Synovitis was induced by an intra-articular injection of 100 ng recombinant equine interleukin 1 beta (reIL-1ß) or 0.5 ng lipopolysaccharide (LPS) into a middle carpal joint in 1 ml volumes. One ml of saline was injected into the contra-lateral control joint. Lameness evaluations were conducted through post-injection hour (PIH) 8 (at which time arthroscopic removal of synovium and articular biopsies was done), and at PIH 240. Arthrocentesis collection of synovial fluid occurred between PIH 0 and 48. An arthroscopic examination at PIH 8 included synovium and articular cartilage biopsies for gene expression analysis. RESULTS: Synovial fluid analysis indicated that single injections of reIL-1ß or LPS increased synovial white blood cell (WBC), neutrophil count, total protein, prostaglandin E(2) (PGE(2)) concentrations and general matrix metalloproteinase (MMP) activity relative to control joints through PIH 8. Injections of either reIL-1ß or LPS increased mRNA expression for MMP-1 and a disintegrin and metalloprotease with thrombospondin motifs (ADAMTS)-4 in synovium and for MMP-1, ADAMTS-4, ADAMTS-5 in articular cartilage collected at PIH 8 compared to saline injections. CONCLUSION: Injections of reIL-1ß into equine carpal joints resulted in a transient inflammatory response that was similar in severity to the LPS injection, causing increased expression of certain deleterious mediators in joint tissues at 8 h. Given that IL-1ß is a known critical mediator of traumatic arthritis and OA, this humane and temporary model may be useful in evaluating therapeutics that act against early stages of joint disease.

Expression of ADAMTS-1, ADAMTS-4, ADAMTS-5 and TIMP3 by hepatocellular carcinoma cell lines.

Little is known about the expression or role of ADAMTS-1, -4 and -5 and their endogenous inhibitor TIMP3 in the liver in physiological and pathological conditions. Their expression was, therefore, investigated in the hepatocellular carcinoma cell lines HepG2 and HuH-7 using qRT-PCR and western blotting, and their cellular localisation by immunocytochemistry. Cytokine treatments were used to assess mRNA and protein modulation. ADAMTS-1, -4, -5 and TIMP3 mRNA and protein were detected in both HepG2 and HuH-7 cells. IL-1ß and IL-6 treatments significantly modulated ADAMTS-1 mRNA expression and IL-1ß treatment ADAMTS-4 mRNA expression in HepG2 cells. Modulations of mRNA by ≥ 5-fold did not translate to increased protein expression. This study showed that ADAMTS-1, -4, -5 and TIMP3 were expressed at differential levels in hepatocellular carcinoma cell lines. The pro-inflammatory cytokines IL-1ß, TNF-α or IL-6 induced changes in mRNA expression, although these did not translate to the protein level.

Expression of ADAMTS-2, -3, -13, and -14 in culprit coronary lesions in patients with acute myocardial infarction or stable angina.

ADAMTS (a disintegrin and metalloproteinase with thrombospondin type 1 motifs) proteases are emerging as key participants in the pathogenesis of vascular diseases. We studied the expression of ADAMTS-2, -3, -4 and -14 in the culprit plaques from patients presenting with acute myocardial infarction (AMI) versus stable angina. Tissue samples were gathered from 52 patients with AMI (n = 35) or stable angina (n = 17) who underwent directional coronary atherectomy. The specimens were stained with hematoxylin-eosin and analyzed immunohistochemically using antibodies specific to ADAMTS-2, -3, -13 and -14, and markers for endothelial cells, macrophages, and smooth muscle cells. Baseline characteristics of the groups were mostly similar. The proportion of smooth muscle α-actin-immunopositive area was smaller in the AMI group than in the stable angina group, but the areas immunopositive for CD31 or CD68 were higher in the AMI group. The relative areas immunopositive for ADAMTS-2, -3, and -13 in AMI were significantly larger than those in stable angina. However, the proportion of areas immunopositive for ADAMTS-14 did not differ between the two groups. Areas that stained for ADAMTS-2, -3, -13, and -14 largely overlapped with those positive for CD31 or CD68. The areas immunopositive for ADAMTS proteases were significantly correlated with CD31- or CD68-immunostained areas. In conclusions, ADAMTS-2, -3, and -13 expression, but not that of ADAMTS-14, are increased in plaques causing AMI compared those associated with stable angina. These results support a role for these enzymes in the pathogenesis of AMI.

Platelet-rich plasma releasate inhibits inflammatory processes in osteoarthritic chondrocytes.

BACKGROUND: Platelet-rich plasma (PRP) has recently been postulated as a treatment for osteoarthritis (OA). Although anabolic effects of PRP on chondrocytes are well documented, no reports are known addressing effects on cartilage degeneration. Since OA is characterized by a catabolic and inflammatory joint environment, the authors investigated whether PRP was able to counteract the effects of such an environment on human osteoarthritic chondrocytes. HYPOTHESIS: Platelet-rich plasma inhibits inflammatory effects of interleukin-1 (IL-1) beta on human osteoarthritic chondrocytes. STUDY DESIGN: Controlled laboratory study. METHODS: Human osteoarthritic chondrocytes were cultured in the presence of IL-1 beta to mimic an osteoarthritic environment. Medium was supplemented with 0%, 1%, or 10% PRP releasate (PRPr, the active releasate of PRP). After 48 hours, gene expression of collagen type II alpha 1 (COL2A1), aggrecan (ACAN), a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)4, ADAMTS5, matrix metalloproteinase (MMP)13, and prostaglandin-endoperoxide synthase (PTGS)2 was analyzed. Additionally, glycosaminoglycan (GAG) content, nitric oxide (NO) production, and nuclear factor kappa B (NFκB) activation were studied. RESULTS: Platelet-rich plasma releasate diminished IL-1 beta-induced inhibition of COL2A1 and ACAN gene expression. The PRPr also reduced IL-1 beta-induced increase of ADAMTS4 and PTGS2 gene expression. ADAMTS5 gene expression and GAG content were not influenced by IL-1 beta or additional PRPr. Matrix metalloproteinase 13 gene expression and NO production were upregulated by IL-1 beta but not affected by added PRPr. Finally, PRPr reduced IL-1 beta-induced NFκB activation to control levels containing no IL-1 beta. CONCLUSION: Platelet-rich plasma releasate diminished multiple inflammatory IL-1 beta-mediated effects on human osteoarthritic chondrocytes, including inhibition of NFκB activation. CLINICAL RELEVANCE: Platelet-rich plasma releasate counteracts effects of an inflammatory environment on genes regulating matrix degradation and formation in human chondrocytes. Platelet-rich plasma releasate decreases NFκB activation, a major pathway involved in the pathogenesis of OA. These results encourage further study of PRP as a treatment for OA.

Expression of ADAMTS4 in Ewing's sarcoma.

Ewing's sarcoma (EWS) is a malignant bone tumor that frequently occurs in teenagers. Genetic mutations which cause EWS have been investigated, and the most frequent one proved to be a fusion gene between EWS gene of chromosome 22 and the FLI1 gene of chromosome 11. However, a limited numbers of useful biological markers for diagnosis of EWS are available. In this study, we identified ADAMTS4 (a disintegrin and metalloproteinase with thrombospondin motifs) as a possible tumor marker for EWS using the retrovirus-mediated signal sequence trap method. ADAMTS4 is a secreted protein of 837 amino acids with a predicted molecular mass of 98-100 kDa. It is a member of metalloprotease family, is expressed mainly in cartilage and brain, and regulates the degradation of aggrecans. ADAMTS4 has been suggested to be involved in arthritic diseases and gliomas. Herein, we show that ADAMTS4 mRNA was expressed in all primary EWS samples and all EWS-derived cell lines examined, while its expression was detected only in small subpopulations of other solid tumors. Furthermore, ADAMTS4 expression was found to be regulated by EWS-FLI1 fusion gene-dependent manner. We also demonstrated that ADAMTS4 protein was highly expressed in tumor samples of the patients with EWS by using immunohistochemistry. These results suggest that ADAMTS4 is a novel tumor marker for EWS.

Nobiletin, a citrus polymethoxy flavonoid, suppresses gene expression and production of aggrecanases-1 and -2 in collagen-induced arthritic mice.

Aggrecanase-1/a disintegrin and metalloproteinase with thrombospondin-like motifs (ADAMTS)-4 and aggrecanase-2/ADAMTS-5 have been shown to play crucial roles in cartilage destruction in arthritic diseases, including rheumatoid arthritis and osteoarthritis. In this study, we examined the effects of nobiletin, a citrus polymethoxy flavone, on the expression and production of ADAMTS-4 and -5 in vitro and in vivo. Nobiletin (16-64muM) interfered with the interleukin (IL)-1beta-mediated ADAMTS-4 and -5 mRNA expression in cultured human synovial fibroblasts. Furthermore, intraperitoneal administration of nobiletin (15, 30, and 60mg/kg) also suppressed ADAMTS-4 and -5 mRNA expression in the joint tissues of collagen-induced arthritic (CIA) mice. Immunohistochemical analysis using an antibody against aggrecan neoepitope (NVTEGE(373)) revealed that aggrecanase-mediated degradation of aggrecan in cartilage was effectively inhibited by nobiletin. These results provide novel evidence that nobiletin effectively interferes with gene expression of ADAMTS-4 and -5, and thereby prevents cartilage destruction in CIA mice.

ADAMTS-4 and -8 are inflammatory regulated enzymes expressed in macrophage-rich areas of human atherosclerotic plaques.

OBJECTIVES: Remodeling of extracellular matrix (ECM) plays an important role in inflammatory disorders such as atherosclerosis. ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) is a recently described family of proteinases that is able to degrade the ECM proteins aggrecan and versican expressed in blood vessels. The purpose of the present study was to analyze the expression and regulation of several ADAMTSs before and after macrophage differentiation and after stimulation with IFN-gamma, IL-1beta and TNF-alpha. ADAMTS expression was also examined during atherosclerosis development in mice and in human atherosclerotic plaques. METHODS AND RESULTS: Real time RTPCR showed that, of the nine different ADAMTS members examined, only ADAMTS-4 and -8 were induced during monocyte to macrophage differentiation, which was also seen at protein level. Macrophage expression of ADAMTS-4, -7, -8 and -9 mRNA were enhanced upon stimulation with IFN-gamma or TNF-alpha. Furthermore, immunohistochemical analyses revealed that ADAMTS-4 and -8 were expressed in macrophage rich areas of human atherosclerotic carotid plaques and coronary unstable plaques. In addition, ADAMTS-4 expression was upregulated during the development of atherosclerosis in LDLR(-/-)ApoB(100/100) mice. Whereas ADAMTS-4 expression was low in non-atherosclerotic aortas, it was significantly higher in aortas from 30-40-week old atherosclerotic animals. CONCLUSION: The present study suggests that ADAMTS-4 and -8 are inflammatory regulated enzymes expressed in macrophage-rich areas of atherosclerotic plaques. This is the first study associating ADAMTS-4 and -8 expression with atherosclerosis. However, further experiments are required to understand the physiological and pathological functions of ADAMTS in the vascular wall, and tools to measure ADAMTS activity need to be developed.