ADAMTS-7: a metalloproteinase that directly binds to and degrades cartilage oligomeric matrix protein

Serum ADAMTS-9 Level in Newborn Babies with Congenital Heart Disease

OBJECTIVE

 A Disintegrin and Metalloproteinase with Thrombospondin-9 (ADAMTS-9), one of the ADAMTS enzymes, is expressed in all fetal tissues, unlike other ADAMTS enzymes, and is thus thought to play a role in fetal development. In this context, the objective of this study is to investigate the relationship between ADAMTS-9 activity and the development of congenital heart diseases (CHD) with a view to using ADAMTS-9 level as a biomarker for CHDs.

STUDY DESIGN

 Newborns diagnosed with CHD and healthy newborns were included in the study as the CHD and control groups, respectively. Gestational age, maternal age, and mode of delivery information pertaining to the mothers and Apgar score and birthweight information pertaining to the newborns were recorded. Blood samples were taken from all newborns to determine their ADAMTS-9 levels in the first 24 hours of life.

RESULTS

 Fifty-eight newborns with CHD and 46 healthy newborns were included in the study. Median ADAMTS-9 levels were 46.57 (interquartile range [IQR]: 33.31 [min: 26.92, max: 124.25]) and 23.36 (IQR: 5.48 [min: 11.7, max: 37.71]) ng/mL in the CHD and control groups, respectively. ADAMTS-9 levels in the CHD group were statistically significantly higher than in the control group (p = 0.000). ADAMTS-9 levels of the CHD and control groups were analyzed by the receiver operating characteristics curve. The area under the curve value for ADAMTS-9 levels of >27.86 ng/mL as the cut-off value for predicting the development of CHD in newborns was 0.836 (95% confidence interval [CI]: 0.753-0.900, p = 0.0001). ADAMTS-9 levels of >27.86 ng/mL were determined to predict the development of CHD in newborns with a sensitivity of 77.78% (95% CI: 65.5-87.38) and a specificity of 84.78% (95% CI: 71.1-93.60).

CONCLUSION

 In conclusion, it was found that the serum ADAMTS-9 levels were significantly higher in newborns with CHD than in healthy newborns. In parallel, ADAMTS-9 levels above a certain cut-off value were associated with CHD.

KEY POINTS

· ADAMTS-9 is expressed in fetal tissues.. · Its level increases in congenital heart diseases.. · It can be used as a biochemical marker in diagnosis..

BAY-9835: Discovery of the First Orally Bioavailable ADAMTS7 Inhibitor

The matrix metalloprotease ADAMTS7 has been identified by multiple genome-wide association studies as being involved in the development of coronary artery disease. Subsequent research revealed the proteolytic function of the enzyme to be relevant for atherogenesis and restenosis after vessel injury. Based on a publicly known dual ADAMTS4/ADAMTS5 inhibitor, we have in silico designed an ADAMTS7 inhibitor of the catalytic domain, which served as a starting point for an optimization campaign. Initially our inhibitors suffered from low selectivity vs MMP12. An X-ray cocrystal structure inspired us to exploit amino acid differences in the binding site of MMP12 and ADAMTS7 to improve selectivity. Further optimization composed of employing 5-membered heteroaromatic groups as hydantoin substituents to become more potent on ADAMTS7. Finally, fine-tuning of DMPK properties yielded BAY-9835, the first orally bioavailable ADAMTS7 inhibitor. Further optimization to improve selectivity vs ADAMTS12 seems possible, and a respective starting point could be identified.

Genetic architecture of cardiac dynamic flow volumes

Cardiac blood flow is a critical determinant of human health. However, the definition of its genetic architecture is limited by the technical challenge of capturing dynamic flow volumes from cardiac imaging at scale. We present DeepFlow, a deep-learning system to extract cardiac flow and volumes from phase-contrast cardiac magnetic resonance imaging. A mixed-linear model applied to 37,653 individuals from the UK Biobank reveals genome-wide significant associations across cardiac dynamic flow volumes spanning from aortic forward velocity to aortic regurgitation fraction. Mendelian randomization reveals a causal role for aortic root size in aortic valve regurgitation. Among the most significant contributing variants, localizing genes (near ELN, PRDM6 and ADAMTS7) are implicated in connective tissue and blood pressure pathways. Here we show that DeepFlow cardiac flow phenotyping at scale, combined with genotyping data, reinforces the contribution of connective tissue genes, blood pressure and root size to aortic valve function.

Analysis of Zinc and Stromal Immunity in Disuse Osteoporosis: Mendelian Randomization and Transcriptomic Analysis

OBJECTIVE

Disuse osteoporosis is known to be primarily caused by a lack of exercise. However, the causal relationships between zinc and immunity and disuse osteoporosis remain unknown. This study investigated these relationships and their potential mechanisms.

METHODS

This study was an integrative study combining genome-wide association studies and transcriptomics. Two-sample Mendelian randomization analysis (MR) was used to analyze the causal relationships between exposures (zinc, immunity, physical activity) and the outcome (osteoporosis) with the aid of single-nucleotide polymorphisms (SNPs) as instrumental variables (IVs). Four models, MR-Egger, inverse variance weighted, weighted median and MR-Pleiotrophy RESidual Sum and Outlier (MRPRESSO), were used to calculate odds ratio values. Sensitivity and heterogeneity analyses were also performed using MRPRESSO and MR-Egger methods. The mRNA transcriptomic analysis was subsequently conducted. Zinc metabolism scores were acquired through single-sample Gene Set Enrichment Analysis algorithms. Stromal scores were obtained using the R Package "estimate" algorithms. Important Kyoto Encyclopedia of Genes and Genomes and Gene Ontology pathways were also derived through gene set variation analysis. Cytoscape software helped construct the transcription factor (TF)-mRNA-microRNA (miRNA) network. Virtual screening and molecular docking were performed. Polymerase chain reaction validation was also carried out in vivo.

RESULTS

Causal relationships were demonstrated between zinc and exercise (95% confidence interval [CI] = 1.30-2.95, p = 0.001), exercise and immunity (95% CI = 0.36-0.80, p = 0.002), exercise and osteoporosis (95% CI = 0.97-0.99, p = 0.0007), and immunity disorder and osteoporosis (95% CI = 1.30-2.03, p = 0.00002). One hundred and seventy-nine mRNAs in important modules were screened. Combining the differential expressional genes (DEGs) and the Boruta selection, six DEGs were screened (AHNAK, CSF2, ADAMTS12, SRA1, RUNX2, and SLC39A14). TF HOXC10 and miRNA hsa-miR-204 were predicted. Then, the TF-mRNA-miRNA network was successfully constructed. RUNX2 and SLC39A14 were identified as hub mRNAs in the TF-mRNA-miRNA network. Eventually, the novel small drug C6O4NH5 was designed according to the pharmacophore structure of SLC39A14. The docking energy for the novel drug was -5.83 kcal/mol. SLC39A14 and RUNX2 were downregulated (of statistical significance p-value < 0.05) in our animal experiment.

CONCLUSION

This study revealed that zinc had a protective causal relationship with disuse osteoporosis by promoting exercise and immunity. SLC39A14 and RUNX2 mRNA participated in this zinc-related mechanism.

Genetic Polymorphisms of Ischemic Stroke in Asians

The increasing incidence of ischemic stroke emphasizes the necessity for early detection and preventive strategies. Diagnostic biomarkers currently available for ischemic stroke only become detectable shortly before the manifestation of stroke symptoms. Genetic variants associated with ischemic stroke offer a potential solution to address this diagnostic limitation. However, it is crucial to acknowledge that genetic variants cannot be modified in the same way as epigenetic changes. Nevertheless, individuals carrying risk or protective variants can modify their lifestyle to potentially influence the associated epigenetic factors. This study aims to summarize specific variants relevant to Asian populations that may aid in the early detection of ischemic stroke and explore their impact on the disease's pathophysiology. These variants give us important information about the genes that play a role in ischemic stroke by affecting things like atherosclerosis pathway, blood coagulation pathway, homocysteine metabolism, transporter function, transcription, and the activity of neurons regulation. It is important to recognize the variations in genetic variants among different ethnicities and avoid generalizing the pathogenesis of ischemic stroke.

Phylogenetic inference of the emergence of sequence modules and protein-protein interactions in the ADAMTS-TSL family

Numerous computational methods based on sequences or structures have been developed for the characterization of protein function, but they are still unsatisfactory to deal with the multiple functions of multi-domain protein families. Here we propose an original approach based on 1) the detection of conserved sequence modules using partial local multiple alignment, 2) the phylogenetic inference of species/genes/modules/functions evolutionary histories, and 3) the identification of co-appearances of modules and functions. Applying our framework to the multidomain ADAMTS-TSL family including ADAMTS (A Disintegrin-like and Metalloproteinase with ThromboSpondin motif) and ADAMTS-like proteins over nine species including human, we identify 45 sequence module signatures that are associated with the occurrence of 278 Protein-Protein Interactions in ancestral genes. Some of these signatures are supported by published experimental data and the others provide new insights (e.g. ADAMTS-5). The module signatures of ADAMTS ancestors notably highlight the dual variability of the propeptide and ancillary regions suggesting the importance of these two regions in the specialization of ADAMTS during evolution. Our analyses further indicate convergent interactions of ADAMTS with COMP and CCN2 proteins. Overall, our study provides 186 sequence module signatures that discriminate distinct subgroups of ADAMTS and ADAMTSL and that may result from selective pressures on novel functions and phenotypes.

ADAMTS7: a Novel Therapeutic Target in Atherosclerosis

PURPOSE OF REVIEW

Genome-wide association studies have repeatedly linked the metalloproteinase ADAMTS7 to coronary artery disease. Here we aim to highlight recent findings surrounding the human genetics of ADAMTS7, novel mouse models that investigate ADAMTS7 function, and potential substrates of ADAMTS7 cleavage.

RECENT FINDINGS

Recent genome-wide association studies in coronary artery disease have replicated the GWAS signal for ADAMTS7 and shown that the signal holds true even across different ethnic groups. However, the direction of effect in humans remains unclear. A recent novel mouse model revealed that the proatherogenicity of ADAMTS7 is derived from its catalytic functions, while at the translational level, vaccinating mice against ADAMTS7 reduced atherosclerosis. Finally, in vitro proteomics approaches have identified extracellular matrix proteins as candidate substrates that may be causal for the proatherogenicity of ADAMTS7. ADAMTS7 represents an enticing target for therapeutic intervention. The recent studies highlighted here have replicated prior findings, confirming the genetic link between ADAMTS7 and atherosclerosis, while providing further evidence in mice that ADAMTS7 is a targetable proatherogenic enzyme.

Genome-wide identification of bovine ADAMTS gene family and analysis of its expression profile in the inflammatory process of mammary epithelial cells

ADAM metallopeptidase with thrombospondin type 1 motif (ADAMTS) are secreted, multi-domain matrix-related zinc endopeptidases that play a role in organogenesis, assembly and degradation of extracellular matrix (ECM), cancer and inflammation. Genome-wide identification and analysis of the bovine ADAMTS gene family has not yet been carried out. In this study, 19 ADAMTS family genes were identified in Bos taurus by genome-wide bioinformatics analysis, and they were unevenly distributed on 12 chromosomes. Phylogenetic analysis shows that the Bos taurus ADAMTS are divided into eight subfamilies, with highly consistent gene structures and motifs within the same subfamily. Collinearity analysis showed that the Bos taurus ADAMTS gene family is homologous to other bovine subfamily species, and many ADAMTS genes may be derived from tandem replication and segmental replication. In addition, based on the analysis of RNA-seq data, we found the expression pattern of ADAMTS gene in different tissues. Meanwhile, we also analyzed the expression profile of ADAMTS gene in the inflammatory response of bovine mammary epithelial cells (BMECs) stimulated by LPS by qRT-PCR. The results can provide ideas for understanding the evolutionary relationship and expression pattern of ADAMTS gene in Bovidae, and clarify the theoretical basis of the function of ADAMTS in inflammation.

Controlled extracellular proteolysis of thrombospondins

Limited proteolysis of thrombospondins is a powerful mechanism to ensure dynamic tuning of their activities in the extracellular space. Thrombospondins are multifunctional matricellular proteins composed of multiple domains, each with a specific pattern of interactions with cell receptors, matrix components and soluble factors (growth factors, cytokines and proteases), thus with different effects on cell behavior and responses to changes in the microenvironment. Therefore, the proteolytic degradation of thrombospondins has multiple functional consequences, reflecting the local release of active fragments and isolated domains, exposure or disruption of active sequences, altered protein location, and changes in the composition and function of TSP-based pericellular interaction networks. In this review current data from the literature and databases is employed to provide an overview of cleavage of mammalian thrombospondins by different proteases. The roles of the fragments generated in specific pathological settings, with particular focus on cancer and the tumor microenvironment, are discussed.

Peptide Vaccine Against ADAMTS-7 Ameliorates Atherosclerosis and Postinjury Neointima Hyperplasia

BACKGROUND

The metalloprotease ADAMTS-7 (a disintegrin and metalloproteinase with thrombospondin type 1 motif 7) is a novel locus associated with human coronary atherosclerosis. ADAMTS-7 deletion protects against atherosclerosis and vascular restenosis in rodents.

METHODS

We designed 3 potential vaccines consisting of distinct B cell epitopic peptides derived from ADAMTS-7 and conjugated with the carrier protein KLH (keyhole limpet hemocyanin) as well as aluminum hydroxide as an adjuvant. Arterial ligation or wire injury was used to induce neointima in mice, whereas ApoE^-/- and LDLR^-/- (LDLR [low-density lipoprotein receptor]) mice fed a high-fat diet were applied to assess atherosclerosis. In addition, coronary stent implantation was performed on vaccine-immunized Bama miniature pigs, followed by optical coherence tomography to evaluate coronary intimal hyperplasia.

RESULTS

A vaccine, ATS7vac, was screened out from 3 candidates to effectively inhibit intimal thickening in murine carotid artery ligation models after vaccination. As well, immunization with ATS7vac alleviated neointima formation in murine wire injury models and mitigated atherosclerotic lesions in both hyperlipidemic ApoE^-/- and LDLR^-/- mice without lowering lipid levels. Preclinically, ATS7vac markedly impeded intimal hyperplasia in swine stented coronary arteries, but without significant immune-related organ injuries. Mechanistically, ATS7vac vaccination produced specific antibodies against ADAMTS-7, which markedly repressed ADAMTS-7-mediated COMP (cartilage oligomeric matrix protein) and TSP-1 (thrombospondin-1) degradation and subsequently inhibited vascular smooth muscle cell migration but promoted re-endothelialization.

CONCLUSIONS

ATS7vac is a novel atherosclerosis vaccine that also alleviates in-stent restenosis. The application of ATS7vac would be a complementary therapeutic avenue to the current lipid-lowering strategy for atherosclerotic disease.

The rs3825807 Polymorphism of ADAMTS7 as a Potential Genetic Marker for Myocardial Infarction in Slovenian Subjects with Type 2 Diabetes Mellitus

BACKGROUND

A disintegrin and metalloprotease with thrombospondin motif 7 (ADAMTS-7) was reported to play a role in the migration of vascular smooth muscle cells and neointimal formation. The object of the study was to investigate the association between the rs3825807 polymorphism of ADAMTS7 and myocardial infarction among patients with type 2 diabetes mellitus in a Slovenian cohort.

METHODS

1590 Slovenian patients with type 2 diabetes mellitus were enrolled in this retrospective cross-sectional case-control study. In total, 463 had a history of recent myocardial infarction, and 1127 of the subjects in the control group had no clinical signs of coronary artery disease. Genetic analysis of an rs3825807 polymorphism of ADAMTS7 was performed with logistic regression.

RESULTS

Patients with the AA genotype had a higher prevalence of myocardial infarction than those in the control group in recessive [odds ratio (OR) 1.647; confidence interval (CI) 1.120-2.407; p = 0.011] and co-dominant (OR 2.153; CI 1.215-3.968; p = 0.011) genetic models.

CONCLUSION

We found a statistically significant association between rs3825807 and myocardial infarction in a cohort of Slovenian patients with type 2 diabetes mellitus. We report that the AA genotype might be a genetic risk factor for myocardial infarction.

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.

The Mechanism and Role of ADAMTS Protein Family in Osteoarthritis

Osteoarthritis (OA) is a principal cause of aches and disability worldwide. It is characterized by the inflammation of the bone leading to degeneration and loss of cartilage function. Factors, including diet, age, and obesity, impact and/or lead to osteoarthritis. In the past few years, OA has received considerable scholarly attention owing to its increasing prevalence, resulting in a cumbersome burden. At present, most of the interventions only relieve short-term symptoms, and some treatments and drugs can aggravate the disease in the long run. There is a pressing need to address the safety problems due to osteoarthritis. A disintegrin-like and metalloprotease domain with thrombospondin type 1 repeats (ADAMTS) metalloproteinase is a kind of secretory zinc endopeptidase, comprising 19 kinds of zinc endopeptidases. ADAMTS has been implicated in several human diseases, including OA. For example, aggrecanases, ADAMTS-4 and ADAMTS-5, participate in the cleavage of aggrecan in the extracellular matrix (ECM); ADAMTS-7 and ADAMTS-12 participate in the fission of Cartilage Oligomeric Matrix Protein (COMP) into COMP lyase, and ADAMTS-2, ADAMTS-3, and ADAMTS-14 promote the formation of collagen fibers. In this article, we principally review the role of ADAMTS metalloproteinases in osteoarthritis. From three different dimensions, we explain how ADAMTS participates in all the following aspects of osteoarthritis: ECM, cartilage degeneration, and synovial inflammation. Thus, ADAMTS may be a potential therapeutic target in osteoarthritis, and this article may render a theoretical basis for the study of new therapeutic methods for osteoarthritis.

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.

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.

Antibodies to cartilage oligomeric matrix protein are pathogenic in mice and may be clinically relevant in rheumatoid arthritis

Objective

Cartilage oligomeric matrix protein (COMP) is an autoantigen in rheumatoid arthritis (RA) and experimental models of arthritis. This study was undertaken to investigate the structure, function, and relevance of anti‐COMP antibodies.

Methods

We investigated the pathogenicity of monoclonal anti‐COMP antibodies in mice using passive transfer experiments, and we explored the interaction of anti‐COMP antibodies with cartilage using immunohistochemical staining. The interaction of the monoclonal antibody 15A11 in complex with its specific COMP epitope P6 was determined by x‐ray crystallography. An enzyme‐linked immunosorbent assay and a surface plasma resonance technique were used to study the modulation of calcium ion binding to 15A11. The clinical relevance and value of serum IgG specific to the COMP P6 epitope and its citrullinated variants were evaluated in a large Swedish cohort of RA patients.

Results

The murine monoclonal anti‐COMP antibody 15A11 induced arthritis in naive mice. The crystal structure of the 15A11–P6 complex explained how the antibody could bind to COMP, which can be modulated by calcium ions. Moreover, serum IgG specific to the COMP P6 peptide and its citrullinated variants was detectable at significantly higher levels in RA patients compared to healthy controls and correlated with a higher disease activity score.

Conclusion

Our findings provide the structural basis for binding a pathogenic anti‐COMP antibody to cartilage. The recognized epitope can be citrullinated, and levels of antibodies to this epitope are elevated in RA patients and correlate with higher disease activity, implicating a pathogenic role of anti‐COMP antibodies in a subset of RA patients.

ADAMTS Proteins and Vascular Remodeling in Aortic Aneurysms

Extracellular matrix (ECM) in the vascular wall is a highly dynamic structure composed of a set of different molecules such as elastins, collagens, fibronectin (Fn), laminins, proteoglycans, and polysaccharides. ECM undergoes remodeling processes to regulate vascular smooth muscle and endothelial cells' proliferation, differentiation, and adhesion. Abnormalities affecting the ECM can lead to alteration in cellular behavior and from this, this can conduce to the development of pathologies. Metalloproteases play a key role in maintaining the homeostasis of ECM by mediating the cleavage of different ECM components. There are different types of metalloproteases: matrix metalloproteinases (MMPs), disintegrin and metalloproteinases (ADAMs), and ADAMs with thrombospondin motifs (ADAMTSs). ADAMTSs have been found to participate in cardiovascular physiology and diseases and specifically in aortic aneurysms. This review aims to decipher the potential role of ADAMTS proteins in the physiopathologic development of Thoracic Aortic Aneurysms (TAA) and Abdominal Aortic Aneurysms (AAA). This review will focus on what is known on the ADAMTS family involved in human aneurysms from human tissues to mouse models. The recent findings on THSD4 (encoding ADAMTSL6) mutations in TAA give a new insight on the involvement of the ADAMTS family in TAA.

Progranulin as a Potential Therapeutic Target in Immune-Mediated Diseases

Progranulin (PGRN), a secretory glycoprotein consisting of 593 amino acid residues, is a key actor and regulator of multiple system functions such as innate immune response and inflammation, as well as tissue regeneration. Recently, there is emerging evidence that PGRN is protective in the development of a variety of immune-mediated diseases, including rheumatoid arthritis (RA), inflammatory bowel disease (IBD), type 1 diabetes mellitus (T1DM) and multiple sclerosis (MS) by regulating signaling pathways known to be critical for immunology, particularly the tumor necrosis factor alpha/TNF receptor (TNF-α/TNFR) signaling pathway. Whereas, the role of PGRN in psoriasis, systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) is controversial. This review summarizes the immunological functions of PGRN and its role in the pathogenesis of several immune-mediated diseases, in order to provide new ideas for developing therapeutic strategies for these diseases.

Coronary Artery Disease Genetics Enlightened by Genome-Wide Association Studies

Many cardiovascular diseases are facilitated by strong inheritance. For example, large-scale genetic studies identified hundreds of genomic loci that affect the risk of coronary artery disease. At each of these loci, common variants are associated with disease risk with robust statistical evidence but individually small effect sizes. Only a minority of candidate genes found at these loci are involved in the pathophysiology of traditional risk factors, but experimental research is making progress in identifying novel, and, in part, unexpected mechanisms. Targets identified by genome-wide association studies have already led to the development of novel treatments, specifically in lipid metabolism. This review summarizes recent genetic and experimental findings in this field. In addition, the development and possible clinical usefulness of polygenic risk scores in risk prediction and individualization of treatment, particularly in lipid metabolism, are discussed.

Coronary Disease Association With ADAMTS7 Is Due to Protease Activity

[Figure: see text].

ADAMTS-12: Functions and Challenges for a Complex Metalloprotease

Nineteen members of the ADAMTS family of secreted zinc metalloproteinases are present in the human degradome. A wide range of different functions are being attributed to these enzymes and the number of their known substrates is considerably increasing in recent years. ADAMTSs can participate in processes such as fertility, inflammation, arthritis, neuronal and behavioral disorders, as well as cancer. Since its first annotation in 2001, ADAMTS-12 has been described to participate in different processes displayed by members of this family of proteinases. In this sense, ADAMTS-12 performs essential roles in modulation and recovery from inflammatory processes such as colitis, endotoxic sepsis and pancreatitis. ADAMTS-12 has also been involved in cancer development acting either as a tumor suppressor or as a pro-tumoral agent. Furthermore, participation of ADAMTS-12 in arthritis or in neuronal disorders has also been suggested through degradation of components of the extracellular matrix. In addition, ADAMTS-12 proteinase activity can also be modified by interaction with other proteins and thus, can be an alternative way of modulating ADAMTS-12 functions. In this review we revised the most relevant findings about ADAMTS-12 function on the 20th anniversary of its identification.

Hyalectanase Activities by the ADAMTS Metalloproteases

The hyalectan family is composed of the proteoglycans aggrecan, versican, brevican and neurocan. Hyalectans, also known as lecticans, are components of the extracellular matrix of different tissues and play essential roles in key biological processes including skeletal development, and they are related to the correct maintenance of the vascular and central nervous system. For instance, hyalectans participate in the organization of structures such as perineural nets and in the regulation of neurite outgrowth or brain recovery following a traumatic injury. The ADAMTS (A Disintegrin and Metalloprotease domains, with thrombospondin motifs) family consists of 19 secreted metalloproteases. These enzymes also perform important roles in the structural organization and function of the extracellular matrix through interactions with other matrix components or as a consequence of their catalytic activity. In this regard, some of their preferred substrates are the hyalectans. In fact, ADAMTSs cleave hyalectans not only as a mechanism for clearance or turnover of proteoglycans but also to generate bioactive fragments which display specific functions. In this article we review some of the physiological and pathological effects derived from cleavages of hyalectans mediated by ADAMTSs.

A guide to the composition and functions of the extracellular matrix

Extracellular matrix (ECM) is a dynamic 3-dimensional network of macromolecules that provides structural support for the cells and tissues. Accumulated knowledge clearly demonstrated over the last decade that ECM plays key regulatory roles since it orchestrates cell signaling, functions, properties and morphology. Extracellularly secreted as well as cell-bound factors are among the major members of the ECM family. Proteins/glycoproteins, such as collagens, elastin, laminins and tenascins, proteoglycans and glycosaminoglycans, hyaluronan, and their cell receptors such as CD44 and integrins, responsible for cell adhesion, comprise a well-organized functional network with significant roles in health and disease. On the other hand, enzymes such as matrix metalloproteinases and specific glycosidases including heparanase and hyaluronidases contribute to matrix remodeling and affect human health. Several cell processes and functions, among them cell proliferation and survival, migration, differentiation, autophagy, angiogenesis, and immunity regulation are affected by certain matrix components. Structural alterations have been also well associated with disease progression. This guide on the composition and functions of the ECM gives a broad overview of the matrisome, the major ECM macromolecules, and their interaction networks within the ECM and with the cell surface, summarizes their main structural features and their roles in tissue organization and cell functions, and emphasizes the importance of specific ECM constituents in disease development and progression as well as the advances in molecular targeting of ECM to design new therapeutic strategies.

The quest for substrates and binding partners: A critical barrier for understanding the role of ADAMTS proteases in musculoskeletal development and disease

Secreted ADAMTS metalloproteases are involved in the sculpting, remodeling, and erosion of connective tissues throughout the body, including in the musculoskeletal system. ADAMTS proteases contribute to musculoskeletal development, pathological tissue destruction, and are mutated in congenital musculoskeletal disorders. Examples include versican cleavage by ADAMTS9 which is required for interdigital web regression during limb development, ADAMTS5-mediated aggrecan degradation in osteoarthritis resulting in joint erosion, and mutations in ADAMTS10 or ADAMTS17 that cause Weill-Marchesani syndrome, a short stature syndrome with bone, joint, muscle, cardiac, and eye involvement. Since the function of ADAMTS proteases and proteases in general is primarily defined by the molecular consequences of proteolysis of their respective substrates, it is paramount to identify all physiological substrates for each individual ADAMTS protease. Here, we review the current knowledge of ADAMTS proteases and their involvement in musculoskeletal development and disease, focusing on some of their known physiological substrates and the consequences of substrate cleavage. We further emphasize the critical need for the identification and validation of novel ADAMTS substrates and binding partners by describing the principles of mass spectrometry-based approaches and by emphasizing strategies that need to be considered for validating the physiological relevance for ADAMTS-mediated proteolysis of novel putative substrates.

The roles of non-coding RNAs in vascular calcification and opportunities as therapeutic targets

Vascular calcification (VC) is characterized by an accumulation of calcium phosphate crystals inside the vessel wall. VC is often associated with diabetes, chronic kidney disease (CKD), atherosclerosis, and cardiovascular disease (CVD). Even though the number of patients with VC remains prevalent, there are still no approved therapies for the treatment of VC. Since the pathogenesis of VC is diverse and involves multiple factors and mechanisms, it is critical to reveal the novel mechanisms involved in VC. Although protein-coding RNAs involved in VC have been extensively studied, the roles of non-coding RNAs (ncRNAs) are not yet fully understood. The field of ncRNAs has recently received attention, and accumulating evidence from studies in VC suggests that ncRNAs, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), play an important role in the regulation of VC. NcRNAs can modulate VC by acting as promoters or inhibitors and may be useful in the clinical diagnosis and treatment of VC. In this article, we review and discuss ncRNAs that regulate VC and present the therapeutic implications of these ncRNAs.

Identification of cardiovascular health gene variants related to longevity in a Chinese population

Cardiovascular disease (CVD) is one of the most important causes of human death, but no attention has been paid to cardiovascular health genes related to healthy longevity. Therefore, we developed a cohort study to explore such genes in healthy, long-lived Chinese subjects. A total of 13275 healthy elderly people were enrolled, including 5107 healthy long-lived individuals and 8168 age-matched control individuals with low CVD risk. Using a combination of whole-exome sequencing (WES) and genome-wide association studies (GWAS), we identified 2 genetic variants (TFPI rs7586970 T, p=0.013, OR=1.100. ADAMTS7 rs3825807 A, p=0.017, OR=1.198) associated with healthy lipid metabolism and longevity. Furthermore, we showed that an interaction among TFPI rs7586970, ADAMTS7 rs3825807 and APOE ɛ3 maintained normal blood lipid levels in centenarians by stratified analysis of CVD risk factors. Finally, through biological function analysis, we revealed clues regarding the mechanism of factor related to cardiovascular health (FCH) such as lipids and longevity. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that the two variants above may be associated with longevity via FCH lipid metabolism pathways. From a meta-analysis of venous thrombosis patients, we unexpectedly found that rs7586970 T is associated with both longevity and protection against vascular disease.

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.

Elevated serum cartilage oligomeric matrix protein and the metalloproteinase-ADAMTS7 levels are associated with vascular calcification in maintenance hemodialysis patients

BACKGROUND

Vascular calcification is common in maintenance hemodialysis (HD) patients. Recent studies showed that cartilage oligomeric matrix protein (COMP) could protect blood vessels from calcification, but the role of ADAMTS7 was opposite. We aimed to investigate the relationship between serum COMP, ADAMTS7 levels and vascular calcification scores in HD patients.

METHODS

Serum COMP and ADAMTS7 levels were tested by ELISA and we compared calcification scores between high and low COMP groups, also between high and low ADAMTS7 groups. We also investigated the differences of serum COMP and ADAMTS7 levels between mild and severe vascular calcification groups. The relationship between serum COMP and ADAMTS7 levels was analyzed in the end.

RESULTS

Serum COMP and ADAMTS7 levels were both higher in HD patients than in control (29.63 vs 14.23 ng/mL, P = .002, 11.12 vs 2.40 ng/mL, P = .005). Serum COMP levels in severe vascular calcification (VC) group were higher than in mild VC (43.13 ± 28.77 vs 26.75 ± 18.22 ng/mL, P = .010). Serum ADAMTS7 levels were positively correlated with radial and digital arteries (small arteries) calcification scores (r = .249, P = .033). And serum COMP and ADAMTS7 levels were positively correlated (r = .348, P = .026).

CONCLUSIONS

Serum COMP and ADAMTS7 levels were probably associated with vascular calcification scores in HD respectively.

Effect of a coronary-heart-disease-associated variant of ADAMTS7 on endothelial cell angiogenesis

BACKGROUND AND AIMS

Recent studies have unveiled an association between ADAMTS7 gene variation and coronary artery disease (CAD) caused by atherosclerosis. We investigated if the ADAMTS7 Serine214-to-Proline substitution arising from a CAD-associated variant affected angiogenesis, since neovascularization plays an important role in atherosclerosis.

METHODS AND RESULTS

ADAMTS7 knockdown in vascular endothelial cells (ECs) attenuated their angiogenesis potential, whereas augmented ADAMTS7-Ser214 expression had the opposite effect, leading to increased ECs migratory and tube formation ability. Proteomics analysis showed an increase in thrombospondin-1, a reported angiogenesis inhibitor, in culture media conditioned by ECs with ADAMTS7 knockdown and a decrease of thrombospondin-1 in media conditioned by ECs with ADAMTS7-Ser214 overexpression. Cleavage assay indicated that ADAMTS7 possessed thrombospondin-1 degrading activity, which was reduced by the Ser214-to-Pro substitution. The pro-angiogenic effect of ADAMTS7-Ser214 diminished in the presence of a thrombospondin-1 blocking antibody.

CONCLUSIONS

The ADAMTS7 Ser217-to-Pro substitution as a result of ADAMTS7 polymorphism affects thrombospondin-1 degradation, thereby promoting atherogenesis through increased EC migration and tube formation.

Hypomethylation of DNA promoter upregulates ADAMTS7 and contributes to HTR-8/SVneo and JEG-3 cells abnormalities in pre-eclampsia

INTRODUCTION

Accumulating evidences have suggested a crucial role of epigenetics in the initiation and progression of pre-eclampsia (PE). Here, we studied the expression of the metalloproteinase ADAMTS7 and the methylation level of its promoter in PE placentas and investigated ADAMTS7 role in the pathogenesis of PE.

METHODS

We first explored ADAMTS7 expression in PE and normal placentas by reverse transcription quantitative PCR (RT-qPCR), western blot, and immunohistochemistry. Methylation specific PCR (MSP) and bisulfite sequencing PCR (BSP) were performed to evaluate the methylation status of ADAMTS7 promoter. Treatment with 5'-Aza was used to induce demethylation and thereby to explore the direct relationship between promoter methylation and ADAMTS7 expression. CCK8 assay, colony formation assay, and trans-well assay were conducted to assess the viability, migration, and invasion of HTR-8/SVneo and JEG-3 cells.

RESULTS

Our results showed that ADAMTS7 expression was upregulated in PE placentas. Methylation analysis revealed a hypomethylated status of ADAMTS7 promoter regions in PE placenta tissues. Besides, demethylation induced by 5'-Aza directly restored ADAMTS7 expression in trophoblast cells. Finally, overexpression of ADAMTS7 inhibited viability, migration, and invasion of HTR-8/SVneo and JEG-3 cells, while silence of ADAMTS7 by RNA interference reciprocally facilitated cell viability, migration and invasion in vitro.

DISCUSSION

Upregulation of ADAMTS7 by promoter hypomethylation in placenta might contribute to the etiology of PE via suppressing cell functions of trophoblasts.

ADATMS-7 regulates the focal adhesion kinase signaling and promotes invasiveness of trophoblasts in early pregnancy

INTRODUCTION

ADAMTS-7, a member of the disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) family, was recently identified to be associated with cell migration and invasion. However, its function on trophoblasts remains unknown. In this study, we are aimed to investigate the role of ADAMTS-7 on trophoblasts in human first trimester gestation.

METHODS

The expression of ADAMTS-7 in trophoblasts and HTR8/SVneo cells is examined by immunohistochemistry and quantitative real-time PCR. BrdU incorporation and Annexin V/PI staining are utilized to measure the effect of ADAMTS-7 on the proliferation and apoptosis of HTR8/SVneo cells, respectively. In addition, we detect the role of ADAMTS-7 on the invasion ability of HTR8/SVneo cells using matrigel invasion assays. The activation of focal adhesion kinase (FAK) and integrinβ1 induced by ADAMTS-7 were determined by Western blot.

RESULTS

ADAMTS-7 and its substrate cartilage oligomeric matrix protein (COMP) were expressed in both primary human trophoblasts and human trophoblast cell lines. TGF-β1 induced a continuous and significant decrease of ADAMTS-7. Inversely, IL-1β up-regulated the ADAMTS-7 level in a dosage dependent manner. In addition, knockdown of ADAMTS-7 inhibited the growth and invasion of HTR8/SVneo cells. To the contrary, ADAMTS-7 overexpression promoted the growth and invasion of HTR8/SVneo cells. ADAMTS-7 knockdown led to a decreased level of FAK Tyr-397 phosphorylation.

DISCUSSION

Our results suggest that ADAMTS-7 may regulate trophoblasts invasion through focal adhesion kinase (FAK) signaling.

Profile of Matrix-Remodeling Proteinases in Osteoarthritis: Impact of Fibronectin

The extracellular matrix (ECM) is a complex and specialized three-dimensional macromolecular network, present in nearly all tissues, that also interacts with cell surface receptors on joint resident cells. Changes in the composition and physical properties of the ECM lead to the development of many diseases, including osteoarthritis (OA). OA is a chronic degenerative rheumatic disease characterized by a progressive loss of synovial joint function as a consequence of the degradation of articular cartilage, also associated with alterations in the synovial membrane and subchondral bone. During OA, ECM-degrading enzymes, including urokinase-type plasminogen activator (uPA), matrix metalloproteinases (MMPs), and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTSs), cleave ECM components, such as fibronectin (Fn), generating fibronectin fragments (Fn-fs) with catabolic properties. In turn, Fn-fs promote activation of these proteinases, establishing a degradative and inflammatory feedback loop. Thus, the aim of this review is to update the contribution of ECM-degrading proteinases to the physiopathology of OA as well as their modulation by Fn-fs.

Genetic variants of ADAMTS7 confer risk for ischaemic stroke in the Chinese population

Large-scale genome-wide association analyses show an association between ADAMTS7 variations and coronary risk. However, the link between ADAMTS7 variability and ischaemic stroke (IS) has yet to be determined. This study evaluated ADAMTS7 variants with respect to the risk of IS. Genetic association analyses were performed in two independent case-control cohorts with 1279 patients with IS and 1268 age-matched healthy controls. Four variant genotypes of the ADAMTS7 gene were identified using the Multiplex SNaPshot assay. The rs3825807, rs11634042, and rs7173743 variants of ADAMTS7 were related to lower IS risk in both initial and replication cohort. The G-T-T-C and G-T-C-C haplotypes are significantly less prevalent in the IS group than in the control group. Further stratification according to IS subtypes indicated that carriers with the variant alleles of the rs3825807, rs11634042 and rs7173743 variants of ADAMTS7conferred a lower risk of developing large-artery atherosclerosis stroke subtype. Also, the mutated rs3825807 G allele, as well as the mutated rs11634042 T allele of ADAMTS7, are linked to a significant reduction of ADAMTS7 in patients with IS. Our findings confirm the role of ADAMTS7 in the pathophysiology of IS, with potentially significant implications for the prevention, treatment, and development of novel therapies for IS.

Association between ADAMTS7 TagSNPs and the risk of myocardialinfarction

Purpose of the study

Genome-wide association studies have revealed an association of ADAMTS7 polymorphisms with the risk of cardiovascular diseases. Nonetheless, the role of ADAMTS7 polymorphisms on myocardial infarction (MI) risk remains poorly understood. Here, we aim to evaluate the effect of ADAMTS7 tag single nucleotide polymorphisms (SNPs) on individual susceptibility to MI.

Study design

Genotyping of the four tagSNPs (rs1994016, rs3825807, rs4380028 and rs7173743) was performed in 232 MI cases and 661 control subjects using PCR-ligase detection reaction (LDR) method. The association of these four tagSNPs with MI risk was performed with SPSS software.

Results

Multivariate logistic regression analysis showed that ADAMTS7 tagSNP rs3825807 exhibited a significant effect on MI risk. Compared with the TT homozygotes, the CT genotype (OR1.93, 95% CI1.30to 2.85, Pc=0.004) and the combined CC/CT genotypes (OR1.70, 95% CI1.16 to 2.50, Pc=0.028) were statistically significantly associated with the increased risk for MI. Further stratified analysis revealed a more significant association with MI risk among older subjects, hypertensives, non-diabetics and patients with hyperlipidaemia. Consistently, the haplotype rs1994016T–rs3825807C containing rs3825807 C allele exhibited increased MI risk (OR1.52, 95% CI1.10 to 2.10, p=0.010). However, we did not detect any association of the other three tagSNPs with MI risk.

Conclusions

Our finding suggest that ADAMTS7 tagSNP rs3825807 contributes to MI susceptibility in the Chinese Han population. Further studies are necessary to confirm the general validity of our findings and to clarify the underlying mechanism for this association.

Proteomic discovery of substrates of the cardiovascular protease ADAMTS7

The protease ADAMTS7 functions in the extracellular matrix (ECM) of the cardiovascular system. However, its physiological substrate specificity and mechanism of regulation remain to be explored. To address this, we conducted an unbiased substrate analysis using terminal amine isotopic labeling of substrates (TAILS). The analysis identified candidate substrates of ADAMTS7 in the human fibroblast secretome, including proteins with a wide range of functions, such as collagenous and noncollagenous extracellular matrix proteins, growth factors, proteases, and cell-surface receptors. It also suggested that autolysis occurs at Glu-729-Val-730 and Glu-732-Ala-733 in the ADAMTS7 Spacer domain, which was corroborated by N-terminal sequencing and Western blotting. Importantly, TAILS also identified proteolysis of the latent TGF-β-binding proteins 3 and 4 (LTBP3/4) at a Glu-Val and Glu-Ala site, respectively. Using purified enzyme and substrate, we confirmed ADAMTS7-catalyzed proteolysis of recombinant LTBP4. Moreover, we identified multiple additional scissile bonds in an N-terminal linker region of LTBP4 that connects fibulin-5/tropoelastin and fibrillin-1-binding regions, which have an important role in elastogenesis. ADAMTS7-mediated cleavage of LTBP4 was efficiently inhibited by the metalloprotease inhibitor TIMP-4, but not by TIMP-1 and less efficiently by TIMP-2 and TIMP-3. As TIMP-4 expression is prevalent in cardiovascular tissues, we propose that TIMP-4 represents the primary endogenous ADAMTS7 inhibitor. In summary, our findings reveal LTBP4 as an ADAMTS7 substrate, whose cleavage may potentially impact elastogenesis in the cardiovascular system. We also identify TIMP-4 as a likely physiological ADAMTS7 inhibitor.

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/β‐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‐1β 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‐1β 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.

Upregulation of ADAMTS‑7 and downregulation of COMP are associated with spontaneous abortion

A disintegrin and metalloproteinase with thrombospondin motifs 7 (ADAMTS-7) has been revealed to serve an important role in inflammation-associated diseases. However, the role of ADAMTS-7 in spontaneous abortion (SA) remains unclear. In the present study, human and mouse decidual tissues were used to detect the expression of ADAMTS-7 and cartilage oligomeric matrix protein (COMP) in mice with lipopolysaccharide (LPS)-induced abortion (10 mice/group), and in SA humans and the corresponding control group (21 participants in the SA group and 15 participants in the control group). The results revealed that ADAMTS-7 expression was upregulated and that COMP expression was downregulated in the mouse decidual tissue of the LPS-induced abortion group, when compared with that of the normal control group. The results were further confirmed by western blot analysis and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis, which revealed increased ADAMTS-7 and decreased COMP expression at the protein and mRNA levels in mice treated with LPS. Additionally, the expression of ADAMTS-7 was negatively correlated with the expression of COMP in mice, with a correlation coefficient of −0.936 (P<0.001). In addition, the expression of ADAMTS-7 and COMP exhibited was similar in the decidual tissue of SA patients when compared with the levels observed in the tissues of the normal control participants, as demonstrated by increased ADAMTS-7 expression and decreased COMP expression. Western blotting and RT-qPCR analysis revealed that ADAMTS-7 was increased and COMP was decreased in the decidual tissue of SA subjects. The correlation analysis of ADAMTS-7 and COMP in human decidual tissue also revealed a similar result, with a correlation coefficient of −0.836 (P<0.001). The results of the present study demonstrated that ADAMTS-7 was upregulated and COMP was downregulated in the decidual tissues of humans and mice with SA, and a negative correlation was identified between the expression levels of ADAMTS-7 and COMP, thereby providing novel evidence for a better understanding of the pathogenesis of SA, which may lead to improvements in the clinical pregnancy outcomes of these individuals.

The Expression of Thrombospondin-4 Correlates with Disease Severity in Osteoarthritic Knee Cartilage

Osteoarthritis (OA) is a progressive joint disease characterized by a continuous degradation of the cartilage extracellular matrix (ECM). The expression of the extracellular glycoprotein thrombospondin-4 (TSP-4) is known to be increased in injured tissues and involved in matrix remodeling, but its role in articular cartilage and, in particular, in OA remains elusive. In the present study, we analyzed the expression and localization of TSP-4 in healthy and OA knee cartilage by reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry, and immunoblot. We found that TSP-4 protein expression is increased in OA and that expression levels correlate with OA severity. TSP-4 was not regulated at the transcriptional level but we detected changes in the anchorage of TSP-4 in the altered ECM using sequential protein extraction. We were also able to detect pentameric and fragmented TSP-4 in the serum of both healthy controls and OA patients. Here, the total protein amount was not significantly different but we identified specific degradation products that were more abundant in sera of OA patients. Future studies will reveal if these fragments have the potential to serve as OA-specific biomarkers.

Changes in synovial fluid and serum concentrations of cartilage oligomeric matrix protein over 5 years after anterior cruciate ligament rupture: an exploratory analysis in the KANON trial

OBJECTIVE

To monitor longitudinal changes of cartilage oligomeric matrix protein (COMP) in synovial fluid (sf) and serum (s) over 5 years after acute anterior cruciate ligament (ACL) rupture, and to compare results from two commercial COMP immunoassays.

DESIGN

Bio-fluids were collected from 121 patients on six occasions over 5 years after acute ACL injury, and from 25 knee healthy reference subjects. Concentrations of sf- and sCOMP were measured by AnaMar (sCOMP-Ana) and by BioVendor (sf- and sCOMP-Bio) immunoassays; other biomarkers were previously assessed. We used ANCOVA for group comparisons and linear mixed models for associations between biomarkers over 5-years with P < 0.05 considered a statistically significant difference or association.

RESULTS

Compared to the reference group, sfCOMP-Bio concentrations were 2-fold elevated within 6 weeks after ACL injury and remained elevated 5 years thereafter, whereas sCOMP-Bio and sCOMP-Ana concentrations were no different from reference levels at any time point. Over the 5-year period, there was an association between sCOMP-Bio and sCOMP-Ana concentrations, although neither sCOMP-Bio nor sCOMP-Ana associated with sfCOMP-Bio. sfCOMP-Bio associated with SF ARGS-aggrecan, urine type I and II collagens (uNTX-I and uCTX-II) and SF cytokines, while sCOMP-Bio associated inversely with uCTX-II, uNTX-I and SF cytokines.

CONCLUSION

The local process after an acute ACL injury generates increased SF COMP concentrations in the injured knee up to 5 years after injury. This response is not detected in serum. Discrepancies in associations between sCOMP measured by BioVendor and AnaMar immunoassays with other biomarkers indicate differences in detected COMP fragments.

Role of ADAMTS-12 in Protecting Against Inflammatory Arthritis in Mice By Interacting With and Inactivating Proinflammatory Connective Tissue Growth Factor

OBJECTIVE

It has been reported that ADAMTS-12 is a susceptibility gene for rheumatoid arthritis (RA) development, and its level is significantly increased in RA patients. In addition, ADAMTS-12 is reported to be required for inflammation in otherwise healthy subjects. This study was undertaken to determine the role of ADAMTS-12 and the underlying mechanisms in the pathogenesis of inflammatory arthritis.

METHODS

The collagen-induced arthritis (CIA) model was established in ADAMTS-12-deficient mice and their control littermates to determine the role of ADAMTS-12 in vivo. Micro-computed tomography scanning was used to demonstrate the destruction of the ankle joint; histologic analysis illustrated synovitis, pannus formation, and bone and cartilage destruction; enzyme-linked immunosorbent assay was performed to measure serum levels of inflammatory cytokines; and protein-protein interaction assays were performed to detect the interactions of ADAMTS-12 and its various deletion mutants with connective tissue growth factor (CTGF).

RESULTS

Deficiency of ADAMTS-12 led to accelerated inflammatory arthritis in the CIA mouse model. Loss of ADAMTS-12 caused enhanced osteoclastogenesis. In vitro and in vivo protein-protein interaction assays demonstrated that ADAMTS-12 bound and processed CTGF, a previously unrecognized substrate of ADAMTS-12. In addition, deletion of ADAMTS-12 enhanced, while overexpression of ADMATS-12 reduced, CTGF-mediated inflammation. Furthermore, ADAMTS-12 regulation of inflammation was largely lost in CTGF-deficient macrophages. Importantly, blocking of CTGF attenuated elevated inflammatory arthritis seen in the ADAMTS-12-deficient CIA mouse model.

CONCLUSION

This study provides evidence that ADAMTS-12 is a critical regulator of inflammatory arthritis and that this is mediated, at least in part, through control of CTGF turnover.

Cartilage oligomeric matrix protein is a novel notch ligand driving embryonic stem cell differentiation towards the smooth muscle lineage

Cartilage oligomeric matrix protein (COMP), a protective component of vascular extracellular matrix (ECM), maintains the homeostasis of mature vascular smooth muscle cells (VSMCs). However, whether COMP modulates the differentiation of stem cells towards the smooth muscle lineage is still elusive. Firstly, purified mouse COMP directly induced mouse embryonic stem cell (ESC) differentiation into VSMCs both in vitro and in vivo, while the silencing of endogenous COMP markedly inhibited ESC-VSMC differentiation. RNA-Sequencing revealed that Notch signaling was significantly activated by COMP during ESC-VSMC differentiation, whereas the inhibition of Notch signaling attenuated COMP-directed ESC-VSMC differentiation. Furthermore, COMP deficiency inhibited Notch activation and VSMC differentiation in mice. Through silencing distinct Notch receptors, we identified that Notch1 mainly mediated COMP-initiated ESC-VSMC differentiation. Mechanistically, COMP N-terminus directly interacted with the EGF11-12 domain of Notch1 and activated Notch1 signaling, as evidenced by co-immunoprecipitation and mammalian two-hybrid assay. In conclusion, COMP served as a potential ligand of Notch1, thereby driving ESC-VSMC differentiation.

The metalloproteinase-proteoglycans ADAMTS7 and ADAMTS12 provide an innate, tendon-specific protective mechanism against heterotopic ossification

Heterotopic ossification (HO) is a significant clinical problem with incompletely resolved mechanisms. Here, the secreted metalloproteinases ADAMTS7 and ADAMTS12 are shown to comprise a unique proteoglycan class that protects against a tendency toward HO in mouse hindlimb tendons, menisci, and ligaments. Adamts7 and Adamts12 mRNAs were sparsely expressed in murine forelimbs but strongly coexpressed in hindlimb tendons, skeletal muscle, ligaments, and meniscal fibrocartilage. Adamts7-/- Adamts12-/- mice, but not corresponding single-gene mutants, which demonstrated compensatory upregulation of the intact homolog mRNA, developed progressive HO in these tissues after 4 months of age. Adamts7-/- Adamts12-/- tendons had abnormal collagen fibrils, accompanied by reduced levels of the small leucine-rich proteoglycans (SLRPs) biglycan, fibromodulin, and decorin, which regulate collagen fibrillogenesis. Bgn-/0 Fmod-/- mice are known to have a strikingly similar hindlimb HO to that of Adamts7-/- Adamts12-/- mice, implicating fibromodulin and biglycan reduction as a likely mechanism underlying HO in Adamts7-/- Adamts12-/- mice. Interestingly, degenerated human biceps tendons had reduced ADAMTS7 mRNA compared with healthy biceps tendons, which expressed both ADAMTS7 and ADAMTS12. These results suggest that ADAMTS7 and ADAMTS12 drive an innate pathway protective against hindlimb HO in mice and may be essential for human tendon health.

Association of serum ADAMTS-7 levels with left ventricular reverse remodeling after ST-elevation myocardial infarction

BACKGROUND

Left ventricular reverse remodeling (LVRR) in patients with ST-elevation myocardial infarction (STEMI) is associated with a good prognosis. Serum levels of ADAMTS-7 might be used for the prognosis of STEMI. This study aimed to investigate the relationship between serum ADAMTS-7 levels and LVRR.

METHODS

This was a prospective study of 104 patients with STEMI who underwent revascularization and 63 controls. ADAMTS-7 serum levels were measured on days 1, 3, and 7 and in months 1 and 6 after STEMI. A decrease ≥ 15% of the left ventricular end-systolic volume at 6 months was defined as LVRR.

RESULTS

The serum levels of ADAMTS-7 in patients with LVRR were lower than those without LVRR (3.84 ± 2.26 vs. 5.02 ± 2.54, P = 0.032) 7 days after STEMI and the difference between day 7 and day 1 (ΔADAMTS-7) was even significantly lower (- 1.31 ± 0.94 vs. - 0.30 ± 0.22, P = 0.021). Multivariate analysis showed that ΔADAMTS-7_{(day 7 minus day 1)} was independently associated with LVRR (OR = - 0.322, 95% CI = - 0.996 to - 0.074, P = 0.028). Receiver operating characteristic (ROC) curve analysis showed that LVRR could be predicted (sensitivity 89%, specificity 82%, and area under the curve 0.896) when ΔADAMTS-7_{(day 7 minus day 1)} was < - 0.39.

CONCLUSIONS

ΔADAMTS-7_{(day 7 minus day 1)} might be a potential predictive factor for LVRR.

Understanding cardiac extracellular matrix remodeling to develop biomarkers of myocardial infarction outcomes

Cardiovascular Disease (CVD) is the most common cause of death in industrialized countries, and myocardial infarction (MI) is a major CVD with significant morbidity and mortality. Following MI, the left ventricle (LV) undergoes a wound healing response to ischemia that results in extracellular matrix (ECM) scar formation to replace necrotic myocytes. While ECM accumulation following MI is termed cardiac fibrosis, this is a generic term that does not differentiate between ECM accumulation that occurs in the infarct region to form a scar that is structurally necessary to preserve left ventricle (LV) wall integrity and ECM accumulation that increases LV wall stiffness to exacerbate dilation and stimulate the progression to heart failure. This review focuses on post-MI LV ECM remodeling, targeting the discussion on ECM biomarkers that could be useful for predicting MI outcomes.

Quantification of cartilage oligomeric matrix protein (COMP) and a COMP neoepitope in synovial fluid of patients with different joint disorders by novel automated assays

OBJECTIVE

To develop automated immunoassays for the quantification of Cartilage Oligomeric Matrix Protein (COMP) and a COMP neoepitope in synovial fluid and to investigate their diagnostic potential in different joint conditions.

METHODS

Two sandwich immunoassays were developed for the quantification of COMP and a COMP neoepitope, using an automated analyser (IDS-iSYS, Immunodiagnostic Systems, Boldon, UK). Assay performance was evaluated in terms of sensitivity, recovery, linearity, and intra- and inter-assay precision. Clinical performance was evaluated by analysing synovial fluid from patients diagnosed with rheumatoid arthritis (RA), reactive arthritis (ReA), osteoarthritis (OA) or acute trauma (AT).

RESULTS

Both automated assays showed good performance for all parameters tested. Quantification of these biomarkers showed the highest median values for Total COMP in the OA group, followed by the AT group, the ReA group, and the RA group. For the COMP neoepitope the AT group showed the highest median value, followed by the ReA group, the OA group, and the RA group. The ratio COMP neoepitope/Total COMP showed distinct differences between the patients groups, as well as between RA patients with slow or rapid progression of joint damage.

CONCLUSIONS

The newly developed automated assays have a good technical performance, can reliably quantify different epitopes on the COMP molecule and show different levels of the two biomarkers in synovial fluid in patients with different joint diseases. The combination of these two assays, measuring their ratio, shows promise for early detection of patients with RA with different prognosis regarding progression of joint damage.

ADAMTS and ADAM metalloproteinases in osteoarthritis - looking beyond the 'usual suspects'

INTRODUCTION

Matrix metalloproteinases (MMPs) and 'aggrecanase' a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTSs) are well established to play key roles in osteoarthritis (OA) through degradation of extracellular matrix (ECM) type II collagen and aggrecan, and are thus potential targets for development of OA therapies.

OBJECTIVE

This paper aims to provide a comprehensive review of the expression and potential roles of other, lesser-known ADAMTSs and related adamalysins (or a disintegrin and metalloproteinases (ADAMs)) in cartilage, with a view to identifying potentially protective or homeostatic metalloproteinases in the joint and informing consequent selective inhibitor design.

DESIGN

A comprehensive literature search was performed using PubMed terms 'osteoarthritis' and 'ADAMTS' or 'ADAM'.

RESULTS

Several ADAMTSs and ADAMs were identified as having reportedly increased expression in OA. These include enzymes likely to play roles in cartilage matrix anabolism (e.g., the procollagen N-proteinases ADAMTS-2, ADAMTS-3 and ADAMTS-14), chondrocyte differentiation and proliferation (e.g., ADAM9, ADAM10, ADAM12), as well as enzymes contributing to cartilage catabolism (e.g., Cartilage oligomeric protein (COMP)-degrading ADAMTS-7 and ADAMTS-12).

CONCLUSIONS

In addition to the well-characterised MMPs, ADAMTS-4 and ADAMTS-5, many other ADAMTSs and ADAMs are expressed in cartilage and several show significantly altered expression in OA. Studies aimed at elucidating the pathophysiological roles of these enzymes in cartilage will contribute to our understanding of OA pathogenesis and enable design of targeted inhibitors that effectively target metalloproteinase-mediated cartilage degradation while sparing cartilage repair pathways.

ADAMTS-7 is associated with a high-risk plaque phenotype in human atherosclerosis

Several large-scale genome-wide association studies have identified single-nucleotide polymorphisms in the genomic region of A Disintegrin And Metalloproteinase with ThromboSpondin type 1 repeats (ADAMTS)-7 and associations to coronary artery disease. Experimental studies have provided evidence for a functional role of ADAMTS-7 in both injury-induced vascular neointima formation and development of atherosclerotic lesions. However, whether ADAMTS-7 is associated with a specific plaque phenotype in humans has not been investigated. Carotid plaques (n = 206) from patients with and without cerebrovascular symptoms were analyzed for expression of ADAMTS-7 by immunohistochemistry and correlated to components associated with plaque vulnerability. Plaques from symptomatic patients showed increased levels of ADAMTS-7 compared with lesions from asymptomatic patients. High levels of ADAMTS-7 correlated with high levels of CD68-staining and lipid content, but with low smooth muscle cell and collagen content, which together are characteristics of a vulnerable plaque phenotype. ADAMTS-7 levels above median were associated with increased risk for postoperative cardiovascular events. Our data show that ADAMTS-7 is associated with a vulnerable plaque phenotype in human carotid lesions. These data support previous observations of a potential proatherogenic role of ADAMTS-7.

Genetic variants rs1994016 and rs3825807 in ADAMTS7 affect its mRNA expression in atherosclerotic occlusive peripheral arterial disease

AIM

Peripheral artery disease (PAD) is a vascular disease affecting peripheral circulation. Recently, genome-wide association studies revealed a relationship between single nucleotide polymorphisms (SNPs) in ADAMTS7 (a disintegrin and metalloprotease with thrombospondin motif 7) and atherosclerosis. In this study, we aimed to determine ADAMTS7 expression in peripheral blood mononuclear cells (PBMCs) and the frequency of ADAMTS7 rs1994016 and rs3825807 polymorphisms in a sample of Turkish patients with PAD, and to evaluate the association of matrix metalloproteinase (MMP) levels with PAD development.

METHODS

In this case-control study, ADAMTS7mRNA and protein expression was determined using reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) and western blot, respectively, and rs1994016 and rs3825807 variants in ADAMTS7 were determined by real-time PCR in 115 PAD patients and 116 healthy controls. Plasma levels of nine MMPs were determined using a multiplex immunoassay system.

RESULTS

ADAMTS7mRNA levels were significantly higher in PAD patients than in controls (t=-2.75, P=.007). There was no significant difference in the frequencies of rs1994016 and rs3825807 between PAD patients and controls (P>.05). In PAD patients, ADAMTS7mRNA levels were significantly increased for the CC genotype of rs1994016 (t=-2.31, P=.026) and TT genotype of rs3825807 (t=-2.23, P=.032). Furthermore, plasma levels of MMP-1, MMP-3, MMP-7, MMP-10, MMP-12, and MMP-13 were significantly higher in PAD patients than in controls (P<.05).

CONCLUSION

This is the first report of the relationship between PAD and ADAMTS7 expression and the effects of the rs1994016 and rs3825807 variants on PAD development. ADAMTS7 may be associated with PAD development.