ADAMTS7-Mediated Complement Factor H Degradation Potentiates Complement Activation to Contributing to Renal Injuries.

BACKGROUND: The dysfunction of complement factor H (CFH), the main soluble complement negative regulator, potentiates various complement-induced renal injuries. However, insights into the underlying mechanism of CFH dysfunction remain limited. In this study, we investigated whether extracellular protease-mediated degradation accounts for CFH dysfunction in complement-mediated renal injuries. METHODS: An unbiased interactome of lupus mice kidneys identified CFH-binding protease. In vitro cleavage assay clarified CFH degradation. Pristane-induced SLE or renal ischemia-reperfusion (I/R) injury models were used in wild-type and ADAMTS7-/- mice. RESULTS: We identified the metalloprotease ADAMTS7 as a CFH-binding protein in lupus kidneys. Moreover, the upregulation of ADAMTS7 correlated with CFH reduction in both lupus mice and patients. Mechanistically, ADAMTS7 is directly bound to CFH complement control protein (CCP) 1-4 domain and degraded CCP 1-7 domain through multiple cleavages. In mice with lupus nephritis or renal I/R injury, ADAMTS7 deficiency alleviated complement activation and related renal pathologies, but without affecting complement-mediated bactericidal activity. Adeno-associated virus-mediated CFH silencing compromised these protective effects of ADAMTS7 knockout against complement-mediated renal injuries in vivo. CONCLUSION: ADAMTS7-mediated CFH degradation potentiates complement activation and related renal injuries. ADAMTS7 would be a promising anticomplement therapeutic target that does not increase bacterial infection risk.

Long non­coding RNA LINC01960­201 hinders decidualization of endometrial stromal cell in endometriosis: Relevance to endometrial receptivity.

Emerging data have indicated that long non­coding RNAs (lncRNA) are associated with the pathogenesis of endometriosis. However, few are associated with endometriosis­associated infertility. In addition, to the best of our knowledge, the role of lncRNAs in decidual formation during the window of implantation with endometriosis has not been reported to date. Based on our previous results, the aim of the present study was to explore the role of lncRNA long intergenic non­protein coding RNA (LINC)01960­201 in in vitro decidualization of endometrial stromal cells in endometriosis during the window of implantation, as well as to explore the biological function of LINC01960­201, and the regulation of a disintegrin and metalloproteinase with thrombospondin motifs 7 (ADAMTS7), hsa­microRNA (miR)­760 and hsa­miR­608 in the decidualization of endometrial stromal cells with endometriosis. Using miRanda, PITA and RNAhybrid, the present study predicted which miRs share the common target gene ADAMTS7 with LINC01960­201 and the existence of regulatory targets. Dual luciferase vectors were constructed to extract the plasmids and measure the relative fluorescence values in order to estimate target regulatory association between LINC01960­201, ADAMTS7 and miRs. Mid­secretory endometrial tissues were collected from women with endometriosis­associated infertility. From these tissues, endometrial stromal cells were extracted and cultured as primary cultures. Medroxyprogesterone acetate (MPA) and 8­Bromoadenosine 3',5'­cyclic monophosphate (8­Br­cAMP) were added to induce in vitro decidualization, and to knockdown LINC01960­201 and transfect a hsa­miR­608 mimic at the same time. Reverse transcription­quantitative PCR and western blotting were conducted to compare the difference in gene expression between the experimental and negative control groups. No regulatory sites between LINC01960­201 and hsa­miR­608 were identified; however, potential regulatory sites were detected between hsa­miR­608 and the 3'­untranslated region (UTR) of ADAMTS7, whereas neither the 3'­UTR of LINC01960­201 or the 3'­UTR of ADAMTS7 had any regulatory targets with hsa­miR­760. During the process of decidualization of endometrial stromal cells by in vitro induction, the expression of hsa­miR­608 in the knockdown group was significantly higher compared with that of the negative control group after LINC01960­201­knockdown, and the expression of ADAMTS7 in the transfection group was significantly lower compared with that of the negative control group after hsa­miR­608 mimic transfection. In conclusion, it was hypothesized that LINC01960­201 played a notable regulatory role in the decidualization of endometrial stromal cells in women with endometriosis during the window of implantation, and its abnormal expression may lead to the decline of endometrial receptivity and recurrent abortions.

ADAMTS7 Attenuates House Dust Mite-Induced Airway Inflammation and Th2 Immune Responses.

PURPOSE: ADAMTS7 is a secreted metalloproteinase enzyme and proteoglycan associated with the early progression of coronary artery disease. However, there is limited information regarding the role of ADAMTS7 in lung adaptive immunity and inflammation. Thus, we sought to assess whether ADAMTS7 expression in the lung modulates house dust mite (HDM)-induced airway inflammation and Th2 immune response. METHODS: The role of ADAMTS7 in HDM-induced airway disease was assessed in ADAMTS7-deficient (ADAMTS7-/-) mice and compared with the wild-type control mice by flow cytometry, ELISA, and histopathology. Furthermore, the antigen priming capability of dendritic cells (DC) was determined ex vivo by employing coculture with CD4+ OT-II cells. RESULTS: ADAMTS7-/- mice develop an augmented eosinophilic airway inflammation, mucous cell metaplasia, and increased Th2 immune response to inhaled HDM. In addition, allergen uptake by lung DC and migration to draining mediastinal lymph node were significantly increased in ADAMTS7-/- mice, which shows an enhanced capacity to mount allergen-specific T-cell proliferation and effector Th2 cytokine productions. We propose that the mechanism by which ADAMTS7 negatively regulates DC function involves attenuated antigen uptake and presentation capabilities, which reduces allergic sensitization and Th2 immune responses in the lung. CONCLUSION: In aggregate, we provide compelling evidence that ADAMTS7 plays a pivotal role in allergic airway disease and Th2 immunity and would be an attractive target for asthma.

Genome-wide pleiotropy analysis of coronary artery disease and pneumonia identifies shared immune pathways.

Coronary artery disease (CAD) remains the leading cause of death despite scientific advances. Elucidating shared CAD/pneumonia pathways may reveal novel insights regarding CAD pathways. We performed genome-wide pleiotropy analyses of CAD and pneumonia, examined the causal effects of the expression of genes near independently replicated SNPs and interacting genes with CAD and pneumonia, and tested interactions between disruptive coding mutations of each pleiotropic gene and smoking status on CAD and pneumonia risks. Identified pleiotropic SNPs were annotated to ADAMTS7 and IL6R. Increased ADAMTS7 expression across tissues consistently showed decreased risk for CAD and increased risk for pneumonia; increased IL6R expression showed increased risk for CAD and decreased risk for pneumonia. We similarly observed opposing CAD/pneumonia effects for NLRP3. Reduced ADAMTS7 expression conferred a reduced CAD risk without increased pneumonia risk only among never-smokers. Genetic immune-inflammatory axes of CAD linked to respiratory infections implicate ADAMTS7 and IL6R, and related genes.

TAILS Identifies Candidate Substrates and Biomarkers of ADAMTS7, a Therapeutic Protease Target in Coronary Artery Disease.

Loss-of-function mutations in the secreted enzyme ADAMTS7 (a disintegrin and metalloproteinase with thrombospondin motifs 7) are associated with protection for coronary artery disease. ADAMTS7 catalytic inhibition has been proposed as a therapeutic strategy for treating coronary artery disease; however, the lack of an endogenous substrate has hindered the development of activity-based biomarkers. To identify ADAMTS7 extracellular substrates and their cleavage sites relevant to vascular disease, we used TAILS (terminal amine isotopic labeling of substrates), a method for identifying protease-generated neo-N termini. We compared the secreted proteome of vascular smooth muscle and endothelial cells expressing either full-length mouse ADAMTS7 WT, catalytic mutant ADAMTS7 E373Q, or a control luciferase adenovirus. Significantly enriched N-terminal cleavage sites in ADAMTS7 WT samples were compared to the negative control conditions and filtered for stringency, resulting in catalogs of high confidence candidate ADAMTS7 cleavage sites from our three independent TAILS experiments. Within the overlap of these discovery sets, we identified 24 unique cleavage sites from 16 protein substrates, including cleavage sites in EFEMP1 (EGF-containing fibulin-like extracellular matrix protein 1/Fibulin-3). The ADAMTS7 TAILS preference for EFEMP1 cleavage at the amino acids 123.124 over the adjacent 124.125 site was validated using both endogenous EFEMP1 and purified EFEMP1 in a binary in vitro cleavage assay. Collectively, our TAILS discovery experiments have uncovered hundreds of potential substrates and cleavage sites to explore disease-related biological substrates and facilitate activity-based ADAMTS7 biomarker development.

Age-associated changes in the transcriptomes of non-cultured adipose-derived stem cells from young and old mice assessed via single-cell transcriptome analysis.

Adipose-derived stem cells (ASCs) exhibit self-renewal and pluripotency. The differentiation potency of ASCs has been reported to deteriorate with aging; however, relevant studies used ASCs that were isolated and subcultured several times. It is still unclear whether subcultured ASCs accurately reflect the in vivo state. To address this question, we used freshly isolated stromal vascular fractions (SVFs) and performed comprehensive single-cell transcriptome analysis. In this study, we identified three cell populations as putative ASC candidates in SVFs and three novel ASC-related genes: Adamts7, Snai2, and Tgfbr1, that are reported to be negative regulators of cell differentiation. Moreover, we identified age-associated high gene expression levels of Adamts7, Egfr, and Igfbp4 in the earliest differentiation stage of ASCs. These results suggest that aging may make it impossible to maintain the stringency of the regulation of the expression of some genes related to ASC differentiation.

ADAMTS7 degrades Comp to fuel BMP2-dependent osteogenic differentiation and ameliorate oncogenic potential in osteosarcomas.

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents, with a high metastatic potential. Despite dramatic changes in OS treatments over the past decades, their efficiency still remains limited, with severe complications and adverse side effects. Key mechanisms underlining tumorigenesis, metastasis and chemotherapy resistance are currently lacking, in turn hindering any progress with respect to developing effective and safe therapeutic strategies against OS. Recently, ADAMTS7, a member of the disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) family, was shown to be involved in osteogenic differentiation-related pathological processes. ADAMTS7 promotes vascular calcification via disturbing the balance between osteogenic bone morphogenetic protein (BMP)2 (regulating osteogenic differentiation and bone formation during development) and its natural inhibitor cartilage oligomeric matrix protein (Comp). Hence, in the present study, we aimed to investigate the role of ADAMTS7 in the pathological process of OS. We first revealed that ADAMTS7 was decreased in OS tissues. Lower expression of ADAMTS7 was correlated with poor histological differentiation and an advanced clinical stage of OS. Through loss- and gain-function analysis, we further revealed that ADAMTS7 attenuated cell proliferation, migration and invasion, at the same time as promoting the expression of osteogenic differentiation markers in two OS cell lines: MG63 and SAOS2. Moreover, Comp was responsible for the effects of ADAMTS7 on OS pathogenesis by reinforcing cell osteogenic differentiation mediated by BMP2 in vitro. In conclusion, ADAMTS7-mediated degradation of Comp may provide a potential therapeutic target for the treatment of OS.

Upregulation of miR­423 improves autologous vein graft restenosis via targeting ADAMTS­7.

Coronary artery bypass graft (CABG) is one of the primary methods of treating coronary heart disease (CHD); however, vein graft restenosis is a major limiting factor of the effectiveness of CABG. Emerging evidence has indicated that miR­423 is associated with vascular diseases. Additionally, upregulation of a disintegrin and metalloproteinase with thrombospondin motifs­7 (ADAMTS­7) contributes to neointima formation by promoting the proliferation and migration of vascular smooth muscle cells and inhibiting the proliferation and migration of endothelial cells. The aim of the present study was to examine the effects of miR­423 target, ADAMTS­7, on regulating vein graft disease and identify novel biomarkers for use in therapy of vein graft failure (VGF). Aberrant expression of miR­423 in plasma of patients with CHD prior to and following CABG confirms that miR­423 may be a suitable target for preventing VGF. Furthermore, a dual­luciferase reporter gene assay indicated that miR­423 directly interacted with ADAMTS­7 and suppressed its expression. Ectopic expression of miR­423 suppressed ADAMTS­7, resulting in decreased proliferation and migration rates of human umbilical vein smooth muscle cells by targeting ADAMTS­7, but resulted in increased proliferation and migration of human umbilical vein endothelial cells in vitro. Overexpression of miR­423 also enhanced re­endothelialization and decreased neointimal formation in a rat vein graft model. In conclusion, the results of the present study demonstrated that the miR­423/ADAMTS­7 axis may possess potential clinical value for the prevention and treatment of restenosis in patients with CHD following CABG.

lncRNA/mRNA profiling of endometriosis rat uterine tissues during the implantation window.

Endometriosis is associated with changes in long non­coding RNA (lncRNA) and mRNA expression, but the exact changes during the implantation window are unknown. Therefore, this study aimed to explore the lncRNA and mRNA expression profiles in the uterus of rats with endometriosis during the implantation window. A total of 35 non­pregnant female rats were randomized to the endometriosis (n=13), adipose tissue control (n=8) and blank control (n=14) groups. On the 5th day of pregnancy, the rats were sacrificed to obtain uterine tissues. lncRNA and mRNA were analyzed using gene chips. A total of five differentially expressed lncRNA and four mRNA were validated by reverse transcription­quantitative (RT­q)PCR. Immunohistochemistry and western blotting were used to determine the expression of the ADAM metallopeptidase with thrombospondin type 1 motif 7 (Adamts7), tumor protein p53 (Tp53), distal­less homeobox 3 (Dlx3) and pyrimidinergic receptor P2Y6 (P2ry6) proteins. There were 115 upregulated lncRNAs, 51 downregulated lncRNAs, 97 upregulated mRNAs and 85 downregulated mRNAs in the endometriosis group. RT­qPCR confirmed the trends for five lncRNAs and four mRNAs (Adamts7, Tp53, Dlx3 and P2ry6). The relative protein expression levels of Adamts7, P2ry6, Dlx3 and TP53 were significantly different in the endometriosis group (P<0.05 vs. controls). Bioinformatics predicted the co­expression relationship of the selected five lncRNA and four mRNA. Gene ontology and the Kyoto Encyclopedia of Genes and Genomes predicted that Adamts7, P2ry6, Dlx3 and TP53 were involved in endometriosis­related inflammation and reproductive pathways. In conclusion, the changes in the expression of lncRNAs, mRNAs and proteins (Adamts7, P2ry6, Dlx3 and TP53) may possibly affect endometrial receptivity in rats with endometriosis during the implantation window, probably resulting in implantation failure of the embryo.

Wnt and RUNX2 mediate cartilage breakdown by osteoarthritis synovial fibroblast-derived ADAMTS-7 and -12.

Failure of therapeutic approaches for the treatment of osteoarthritis (OA) based on the inhibition of metalloproteinases, might be because of their constitutive expression in homeostasis, together with their network complexity. The knowledge of this network would contribute to selective target pathological conditions. In this sense, blockade of mediators produced by neighbouring joint cells, such as synovial fibroblasts (SF), would prevent cartilage damage. Thus, we studied the contribution of ADAMTS-7 and -12 from SF to cartilage oligomeric matrix protein (COMP) degradation, and the signalling pathways involved in their expression. We report for the first time in SF, the involvement of ERK-Runx2 axis and Wnt/ß-catenin signalling in ADAMTS-12 and ADAMTS-7 expressions, respectively, with the subsequent consequences in COMP degradation from cartilage extracellular matrix. After stimulation with IL-1ß or fibronectin fragments, we showed that ERK inhibition decreased Runx2 activation and ADAMTS-12 expression in OA-SF, also reducing Fn-fs-induced COMP degradation. Blockage of Wnt signalling by DKK1 reduced ADAMTS-7 and COMP degradation in OA-SF as well. In addition, Wnt7B expression was induced by IL-1ß and by itself, also increasing ADAMTS-7. Our results could contribute to the development of disease-modifying OA drugs targeting ADAMTS-7 and -12 for the prevention of extracellular matrix components degradation like COMP.

Genetic Variation at the ADAMTS7 Locus is Associated With Reduced Severity of Coronary Artery Disease.

BACKGROUND: Genome-wide association studies identified ADAMTS7 as a risk locus for coronary artery disease (CAD). Functional studies suggest that ADAMTS7 may promote cellular processes in atherosclerosis. We sought to examine the association between genetic variation at ADAMTS7 and measures of atherosclerosis using histological, angiographic, and clinical outcomes data. METHODS AND RESULTS: The lead CAD-associated single-nucleotide polymorphism rs3825807 at the ADAMTS7 locus was genotyped. The G allele (reduced ADAMTS7 function) was associated with a smaller fibrous cap (P=0.017) and a smaller percentage area of α-actin (smooth muscle cell marker) in the intima (P=0.017), but was not associated with calcification or plaque thickness, following ex vivo immunohistochemistry analysis of human coronary plaques (n=50; mean age 72.2±11.3). In two independent cohorts (Southampton Atherosclerosis Study [n=1359; mean age 62.5±10.3; 70.1% men] and the Emory Cardiovascular Biobank [EmCAB; n=2684; mean age 63.8±11.3; 68.7% men]), the G allele was associated with 16% to 19% lower odds of obstructive CAD (Southampton Atherosclerosis Study: odds ratio, 0.81; 95% confidence interval, 0.67-0.98; EmCAB: odds ratio, 0.84; 95% confidence interval, 0.75-0.95) with similar effects for multivessel, left anterior descending, and proximal CAD. Furthermore, each copy of the G allele was associated with lower angiographic severity Gensini score (Southampton Atherosclerosis Study, P=0.026; EmCAB, P<0.001), lower Sullivan Extent score (Southampton Atherosclerosis Study, P=0.029; EmCAB, P<0.001), and a 23% lower risk of incident revascularization procedures (EmCAB: hazard ratio, 0.76; 95% confidence interval, 0.59-0.98). There were no associations with all-cause mortality or incident myocardial infarction. CONCLUSIONS: Genetic variation at the ADAMTS7 locus is associated with several complementary CAD phenotypes, supporting the emerging role of ADAMTS7 in atherosclerosis and may represent a potential drug target.

Loss of Cardioprotective Effects at the ADAMTS7 Locus as a Result of Gene-Smoking Interactions.

BACKGROUND: Common diseases such as coronary heart disease (CHD) are complex in etiology. The interaction of genetic susceptibility with lifestyle factors may play a prominent role. However, gene-lifestyle interactions for CHD have been difficult to identify. Here, we investigate interaction of smoking behavior, a potent lifestyle factor, with genotypes that have been shown to associate with CHD risk. METHODS: We analyzed data on 60 919 CHD cases and 80 243 controls from 29 studies for gene-smoking interactions for genetic variants at 45 loci previously reported to be associated with CHD risk. We also studied 5 loci associated with smoking behavior. Study-specific gene-smoking interaction effects were calculated and pooled using fixed-effects meta-analyses. Interaction analyses were declared to be significant at a P value of <1.0×10-3 (Bonferroni correction for 50 tests). RESULTS: We identified novel gene-smoking interaction for a variant upstream of the ADAMTS7 gene. Every T allele of rs7178051 was associated with lower CHD risk by 12% in never-smokers (P=1.3×10-16) in comparison with 5% in ever-smokers (P=2.5×10-4), translating to a 60% loss of CHD protection conferred by this allelic variation in people who smoked tobacco (interaction P value=8.7×10-5). The protective T allele at rs7178051 was also associated with reduced ADAMTS7 expression in human aortic endothelial cells and lymphoblastoid cell lines. Exposure of human coronary artery smooth muscle cells to cigarette smoke extract led to induction of ADAMTS7. CONCLUSIONS: Allelic variation at rs7178051 that associates with reduced ADAMTS7 expression confers stronger CHD protection in never-smokers than in ever-smokers. Increased vascular ADAMTS7 expression may contribute to the loss of CHD protection in smokers.

Regulation of a disintegrins and metalloproteinase with thrombospondin motifs 7 during inflammation in nucleus pulposus (NP) cells: role of AP-1, Sp1 and NF-κB signaling.

AIM: The objective of this study is to explore the effect of inflammatory cytokines on a disintegrins and metalloproteinase with thrombospondin motifs 7 (ADAMTS7) and to demonstrate the role of Sp1, AP-1 and NF-κB signaling on the ADAMTS7 regulation during inflammation in NP cells. METHODS: Real-time PCR was to detect the effect of ADAMTS7 knockdown on the expression of catabolic enzymes during inflammatory condition in NP cells. Real-time PCR, western blot, immunofluorescence and transfection experiments were used to observe the effect of tumor necrosis factor-α (TNF-α) or interleukin-1ß on the expression and the activity of ADAMTS7, and demonstrated the role to Sp1, AP-1 and NF-κB in the regulation of ADAMTS7 during inflammation. RESULTS: As other cells, ADAMTS7 knockdown suppressed the mRNA expression of catabolic factors during inflammation in human NP cells. However, the expression of ADAMTS7 mRNA and protein and the activity of ADAMTS7 promoter were refractory to inflammatory cytokines. In addition, Sp1, AP-1, not NF-κB signaling sustained the expression of ADAMTS7 mRNA, protein, as well as promoter activity during inflammation in NP cells. CONCLUSION: ADAMTS7 played a crucial role in the expression of catabolic genes in the presence of TNF-α and AP-1, Sp1, not NF-κB signaling were critical for the maintenance of ADAMTS7 expression during inflammation in NP cells.

Association of ADAMTS-7 Levels with Cardiac Function in a Rat Model of Acute Myocardial Infarction.

BACKGROUND/AIMS: High ADAMTS-7 levels are associated with acute myocardial infarction (AMI), although its involvement in ventricular remodeling is unclear. In this study, we investigated the association between ADAMTS-7 expression and cardiac function in a rat AMI model. METHODS: Sprague-Dawley rats were randomized into AMI (n = 40) and sham (n = 20) groups. The left anterior descending artery was sutured to model AMI. Before surgery and 7, 14, 28, and 42 days post-surgery, ADAMTS-7 and brain natriuretic peptide (BNP), and cartilage oligomeric matrix protein (COMP) were assessed by ELISA, western blot, real-time RT-PCR, and/or immunohistochemistry. Cardiac functional and structural parameters were assessed by M-mode echocardiography. RESULTS: After AMI, plasma ADAMTS-7 levels increased, peaking on day 28 (AMI: 13.2 ± 6.3 vs. sham: 3.4 ± 1.3 ng/ml, P < 0.05). Compared with the sham group, ADAMTS-7 expression was higher in the infarct zone at day 28. COMP present in normal myocardium was degraded by day 28 post-AMI. Plasma ADAMTS-7 correlated positively with BNP (r = 0.642, P = 0.025), left ventricular end-diastolic diameter (r = 0.695, P = 0.041), left ventricular end-systolic diameter (r = 0.710, P = 0.039), left ventricular ejection fraction (r = 0.695, P = 0.036), and left ventricular short-axis fractional shortening (r = 0.721, P = 0.024). CONCLUSIONS: ADAMTS-7 levels may reflect the degree of ventricular remodeling after AMI.

miR-105/Runx2 axis mediates FGF2-induced ADAMTS expression in osteoarthritis cartilage.

UNLABELLED: Fibroblast growth factor 2 (FGF2) plays an important role in the development of osteoarthritis (OA) through the regulation of cartilage degradation. However, the molecular mechanism underlying FGF2-induced OA is poorly characterized. MicroRNAs (miRNAs) maintain cartilage homeostasis. To examine whether FGF2 regulates OA through the modulation of miRNA, we screened potential miRNA molecules that could be regulated through FGF2 using microarray analysis. The results showed that microRNA-105 (miR-105) was significantly downregulated in chondrocytes stimulated with FGF2. Runt-related transcription factor 2 (Runx2), a key transcription factor involved in OA, has been identified as a novel potential target of miR-105. FGF2 suppressed miR-105 expression through the recruitment of the subunit of the nuclear factor kappa B transcription complex p65 to the miR-105 promoter. The knockdown of Runx2 mimicked the effect of miR-105 and abolished the ability of miR-105 to regulate the expression of a disintegrin-like and metalloproteinase with thrombospondin 4 (ADAMTS4), ADAMTS5, ADAMTS7 and ADAMTS12, both of which are responsible for the degradation of collagen 2A1 (COL2A1) and aggrecan (ACAN). miR-105 is also required for FGF2/p65-induced Runx2 activation and ADAMTS expression. Moreover, miR-105 expression was downregulated in OA patients and inversely correlated with the expression of Runx2, ADAMTS7 and ADAMTS12, which were upregulated in OA patients. These data highlight that the FGF2/p65/miR-105/Runx2/ADAMTS axis might play an important role in OA pathogenesis and that miR-105 might be a potential diagnostic target and useful strategy for OA treatment. KEY MESSAGE: Runx2 was identified as a novel direct target of miR-105. FGF2 inhibits miR-105 transcription through recruitment of p65 to miR-105 promoter. p65/miR-105 is essential for FGF2-mediated Runx2 and ADAMTS upregulation. miR-105 is downregulated in OA and inversely correlated with Runx2 expression.

The Function and Roles of ADAMTS-7 in Inflammatory Diseases.

The ADAMTS proteinases are a group of multidomain and secreted metalloproteinases containing the thrombospondin motifs. ADAMTS-7 is a member of ADAMTS family and plays a crucial role in the pathogenesis of arthritis. Overexpression of ADAMTS-7 gene promotes the breakdown of cartilage oligomeric matrix protein (COMP) matrix and accelerates the progression of both surgically induced osteoarthritis and collagen-induced arthritis. Moreover, ADAMTS-7 and tumor necrosis factor-α (TNF-α) form a positive feedback loop in osteoarthritis. More significantly, granulin-epithelin precursor, a growth factor has important roles in bone development and bone-associated diseases, disturbs the interaction between ADAMTS-7 and COMP, and prevents COMP degradation. This review is based on our results and provides an overview of current knowledge of ADAMTS-7, including its structure, function, gene regulation, and inflammatory diseases involvement.

IL-17A enhances ADAMTS-7 expression through regulation of TNF-α in human nucleus pulposus cells.

ADMATS-7 is known to play an important role in the pathogenesis of various diseases, including cartilaginous diseases. IL-17A is an inflammatory cytokine detected in degenerative disc tissues. However, the interplay between IL-17A and ADMATS-7 in human disc degeneration is still unknown. Samples collected from 50 patients were divided into three groups according to MRI degeneration grading system score. Immunohistochemistry, RT-PCR and western Blotting were used to investigate the expression of ADAMTS-7 in NP tissues. Furthermore, a rat disc degeneration model was established, and the expression level of ADAMTS-7 was assayed using immunohistochemistry, RT-PCR and western Blotting. The human NP cells were cultured in the presence and absence of IL-17A stimulation. RNA extracts were collected, and real-time PCR was performed to determine the expression of ADAMTS-7. Moreover, ADAMTS-7 concentrations were detected in human NP cell culture supernatants by ELISA. After culturing NP cells with IL-17A (with or without Etanercept), ADAMTS-7 levels were detected in each group. ADAMTS-7 expression was dramatically elevated in both human and rat degenerative NP tissues compared with normal controls. The RT-PCR and ELISA results revealed that IL-17A could enhance the production of ADAMTS-7, while ADAMTS-7 expression dramatically decreased in the IL-17A + Etanercept group in comparison to the IL-17A alone group. Our results indicate the presence of ADAMTS-7 in human NP cells and imply its potential role in disc degeneration. Additionally, our results indicate that IL-17A induced ADAMTS-7 expression via TNF-α, which may form a molecular axis in human NP cells.

ADAMTS-7 promotes vascular smooth muscle cells proliferation in vitro and in vivo.

Vascular smooth muscle cell (VSMC) proliferation and migration are pivotal for the pathogenesis of atherosclerosis and post-angioplasty restenosis. We have recently reported that a disintegrin and metalloproteinase with thrombospondin motifs-7 (ADAMTS-7), a novel metalloproteinase, contributes directly to neointima formation by mediating VSMC migration. However, whether ADAMTS-7 affects VSMC proliferation remains unclear. In this study, we found that luminal adenoviral delivery of ADAMTS-7 aggravated intimal hyperplasia 7 d after injury, paralleled by an increased percentage of PCNA-positive cells in both intima and media. In contrast, perivascular administration of ADAMTS-7 siRNA, but not scrambled siRNA to injured arteries attenuated intimal thickening at day 7, paralleled with reduced intimal VSMC replication, without alteration of VSMC proliferation in the media. In accordance, [(3)H]-thymidine incorporation assay in primary cultured rat VSMCs revealed an enhanced replication rate (by 61%) upon ADAMTS-7 overexpression and retarded proliferation (by 23%) upon ADAMTS-7 siRNA administration. Our data demonstrates that ADAMTS-7 promotes VSMC proliferation both in vitro and in vivo. ADAMTS-7 may therefore serve as a novel therapeutic target for atherosclerosis and post-angioplasty restenosis.

Overexpression of ADAMTS-7 leads to accelerated initiation and progression of collagen-induced arthritis in mice.

The aim of the present study is to determine whether ADAMTS-7 contributes to the onset and severity of joint inflammation in the pathogenesis of inflammatory arthritis. ADAMTS-7 was found to be elevated in the course of collagen-induced arthritis (CIA). ADAMTS-7 transgenic (TG) mice were more susceptible to the induction of CIA. The onset of CIA was accelerated and the arthritic severity was increased in TG mice compared to wild-type mice. The overall incidence was also significantly higher in TG mice. In addition, arthritic TG mice displayed significantly higher clinical and histological arthritis scores. The COMP degradative fragments were significantly elevated in articular cartilage and sera in CIA models of TG mice. Furthermore, the production of tumor necrosis factor-alpha and interleukin-17 was also increased in serum and draining lymph nodes of arthritic TG mice. Therefore, these data provided the in vivo evidence, suggesting that ADAMTS-7 may play an important role in the pathogenesis of inflammatory arthritis, and that inhibition of ADAMTS-7 may be a potential target to ameliorate the severity of inflammatory arthritis.