ADAMTS1 cleaves aggrecan at multiple sites and is differentially inhibited by metalloproteinase inhibitors

ADAMTS-1 has nuclear localization in cells with epithelial origin and leads to decreased cell migration

In the study of tumorigenesis, the involvement of molecules within the extracellular matrix (ECM) is crucial. ADAMTSs (A Disintegrin and Metalloproteinase with Thrombospondin motifs), a group of secreted proteases known for their role in ECM remodeling, were primarily considered to be extracellular proteases. However, our research specifically detected ADAMTS-1, a member of this family, predominantly within the nucleus of mammary cells. Our main objective was to understand the mechanism of ADAMTS-1 translocation to the nucleus and its functional significance in this cellular compartment. Our investigation uncovered that nuclear ADAMTS-1 was present in cells exhibiting an epithelial phenotype, while cells of mesenchymal origin contained the protease in the cytoplasm. Moreover, disruption of ADAMTS-1 secretion, induced by Monensin treatment, resulted in its accumulation in the cytoplasm. Notably, our research indicated that alterations in the secretory pathways could influence the protease's compartmentalization. Additionally, experiments with conditioned medium from cells containing nuclear ADAMTS-1 demonstrated its internalization into the nucleus by HT-1080 cells and fibroblasts. Furthermore, heightened levels of ADAMTS-1 within the ECM reduced the migratory potential of mesenchymal cells. This highlights the potential significance of nuclear ADAMTS-1 as a critical component within the tumor microenvironment due to its functional activity in this specific cellular compartment.

The C-terminal domains of ADAMTS1 contain exosites involved in its proteoglycanase activity

A disintegrin-like and metalloproteinase with thrombospondin type 1 motifs (ADAMTS1) is a protease involved in fertilization, cancer, cardiovascular development, and thoracic aneurysms. Proteoglycans such as versican and aggrecan have been identified as ADAMTS1 substrates, and Adamts1 ablation in mice typically results in versican accumulation; however, previous qualitative studies have suggested that ADAMTS1 proteoglycanase activity is weaker than that of other family members such as ADAMTS4 and ADAMTS5. Here, we investigated the functional determinants of ADAMTS1 proteoglycanase activity. We found that ADAMTS1 versicanase activity is approximately 1000-fold lower than ADAMTS5 and 50-fold lower than ADAMTS4 with a kinetic constant (kcat/Km) of 3.6 × 103 M-1 s-1 against full-length versican. Studies on domain-deletion variants identified the spacer and cysteine-rich domains as major determinants of ADAMTS1 versicanase activity. Additionally, we confirmed that these C-terminal domains are involved in the proteolysis of aggrecan as well as biglycan, a small leucine-rich proteoglycan. Glutamine scanning mutagenesis of exposed positively charged residues on the spacer domain loops and loop substitution with ADAMTS4 identified clusters of substrate-binding residues (exosites) in β3-β4 (R756Q/R759Q/R762Q), β9-β10 (residues 828-835), and β6-β7 (K795Q) loops. This study provides a mechanistic foundation for understanding the interactions between ADAMTS1 and its proteoglycan substrates and paves the way for development of selective exosite modulators of ADAMTS1 proteoglycanase activity.

Hypochlorous Acid and Chloramines Induce Specific Fragmentation and Cross-Linking of the G1-IGD-G2 Domains of Recombinant Human Aggrecan, and Inhibit ADAMTS1 Activity

Atherosclerosis is a chronic inflammatory disease and a leading cause of mortality. It is characterized by arterial wall plaques that contain high levels of cholesterol and other lipids and activated leukocytes covered by a fibrous cap of extracellular matrix (ECM). The ECM undergoes remodelling during atherogenesis, with increased expression of aggrecan, a proteoglycan that binds low-density-lipoproteins (LDL). Aggrecan levels are regulated by proteases, including a disintegrin and metalloproteinase with thrombospondin motifs 1 (ADAMTS1). Activated leukocytes release myeloperoxidase (MPO) extracellularly, where it binds to proteins and proteoglycans. Aggrecan may therefore mediate colocalization of MPO and LDL. MPO generates hypochlorous acid (HOCl) and chloramines (RNHCl species, from reaction of HOCl with amines on amino acids and proteins) that damage LDL and proteins, but effects on aggrecan have not been examined. The present study demonstrates that HOCl cleaves truncated (G1-IGD-G2) recombinant human aggrecan at specific sites within the IGD domain, with these being different from those induced by ADAMTS1 which also cleaves within this region. Irreversible protein cross-links are also formed dose-dependently. These effects are limited by the HOCl scavenger methionine. Chloramines including those formed on amino acids, proteins, and ECM materials induce similar damage. HOCl and taurine chloramines inactivate ADAMTS1 consistent with a switch from proteolytic to oxidative aggrecan fragmentation. Evidence is also presented for colocalization of aggrecan and HOCl-generated epitopes in advanced human atherosclerotic plaques. Overall, these data show that HOCl and chloramines can induce specific modifications on aggrecan, and that these effects are distinct from those of ADAMTS1.

The Biochemistry and Physiology of A Disintegrin and Metalloproteinases (ADAMs and ADAM-TSs) in Human Pathologies

Metalloproteinases are a group of proteinases that plays a substantial role in extracellular matrix remodeling and its molecular signaling. Among these metalloproteinases, ADAMs (a disintegrin and metalloproteinases) and ADAM-TSs (ADAMs with thrombospondin domains) have emerged as highly efficient contributors mediating proteolytic processing of various signaling molecules. ADAMs are transmembrane metalloenzymes that facilitate the extracellular domain shedding of membrane-anchored proteins, cytokines, growth factors, ligands, and their receptors and therefore modulate their biological functions. ADAM-TSs are secretory, and soluble extracellular proteinases that mediate the cleavage of non-fibrillar extracellular matrix proteins. ADAMs and ADAM-TSs possess pro-domain, metalloproteinase, disintegrin, and cysteine-rich domains in common, but ADAM-TSs have characteristic thrombospondin motifs instead of the transmembrane domain. Most ADAMs and ADAM-TSs are activated by cleavage of pro-domain via pro-protein convertases at their N-terminus, hence directing them to various signaling pathways. In this article, we are discussing not only the structure and regulation of ADAMs and ADAM-TSs, but also the importance of these metalloproteinases in various human pathophysiological conditions like cardiovascular diseases, colorectal cancer, autoinflammatory diseases (sepsis/rheumatoid arthritis), Alzheimer's disease, proliferative retinopathies, and infectious diseases. Therefore, based on the emerging role of ADAMs and ADAM-TSs in various human pathologies, as summarized in this review, these metalloproteases can be considered as critical therapeutic targets and diagnostic biomarkers.

Role of ADAM and ADAMTS Disintegrin and Metalloproteinases in Normal Pregnancy and Preeclampsia

Normal pregnancy (NP) involves intricate processes starting with egg fertilization, proceeding to embryo implantation, placentation and gestation, and culminating in parturition. These pregnancy-related processes require marked uteroplacental and vascular remodeling by proteolytic enzymes and metalloproteinases. A disintegrin and metalloproteinase (ADAM) and ADAM with thrombospondin motifs (ADAMTS) are members of the zinc-dependent family of proteinases with highly conserved protein structure and sequence homology, which include a pro-domain, and a metalloproteinase, disintegrin and cysteine-rich domain. In NP, ADAMs and ADAMTS regulate sperm-egg fusion, embryo implantation, trophoblast invasion, placental angiogenesis and spiral arteries remodeling through their ectodomain proteolysis of cell surface cytokines, cadherins and growth factors as well as their adhesion with integrins and cell-cell junction proteins. Preeclampsia (PE) is a serious complication of pregnancy characterized by new-onset hypertension (HTN) in pregnancy (HTN-Preg) at or after 20 weeks of gestation, with or without proteinuria. Insufficient trophoblast invasion of the uterine wall, inadequate expansive remodeling of the spiral arteries, reduced uteroplacental perfusion pressure, and placental ischemia/hypoxia are major initiating events in the pathogenesis of PE. Placental ischemia/hypoxia increase the release of reactive oxygen species (ROS), which lead to aberrant expression/activity of certain ADAMs and ADAMTS. In PE, abnormal expression/activity of specific ADAMs and ADAMTS that function as proteolytic sheddases could alter proangiogenic and growth factors, and promote the release of antiangiogenic factors and inflammatory cytokines into the placenta and maternal circulation leading to generalized inflammation, endothelial cell injury and HTN-Preg, renal injury and proteinuria, and further decreases in uteroplacental blood flow, exaggeration of placental ischemia, and consequently fetal growth restriction. Identifying the role of ADAMs and ADAMTS in NP and PE has led to a better understanding of the underlying molecular and vascular pathways, and advanced the potential for novel biomarkers for prediction and early detection, and new approaches for the management of PE.

Targeting Autophagy for Developing New Therapeutic Strategy in Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) is a prevalent cause of low back pain. IVDD is characterized by abnormal expression of extracellular matrix components such as collagen and aggrecan. In addition, it results in dysfunctional growth, senescence, and death of intervertebral cells. The biological pathways involved in the development and progression of IVDD are not fully understood. Therefore, a better understanding of the molecular mechanisms underlying IVDD could aid in the development of strategies for prevention and treatment. Autophagy is a cellular process that removes damaged proteins and dysfunctional organelles, and its dysfunction is linked to a variety of diseases, including IVDD and osteoarthritis. In this review, we describe recent research findings on the role of autophagy in IVDD pathogenesis and highlight autophagy-targeting molecules which can be exploited to treat IVDD. Many studies exhibit that autophagy protects against and postpones disc degeneration. Further research is needed to determine whether autophagy is required for cell integrity in intervertebral discs and to establish autophagy as a viable therapeutic target for IVDD.

Induction of A Disintegrin and Metalloproteinase with Thrombospondin motifs 1 by a rare variant or cognitive activities reduces hippocampal amyloid-β and consequent Alzheimer’s disease risk

Amyloid-β (Aβ) derived from amyloid precursor protein (APP) hydrolysis is acknowledged as the predominant hallmark of Alzheimer’s disease (AD) that especially correlates to genetics and daily activities. In 2019, meta-analysis of AD has discovered five new risk loci among which A Disintegrin and Metalloproteinase with Thrombospondin motifs 1 (ADAMTS1) has been further suggested in 2021 and 2022. To verify the association, we re-sequenced ADAMTS1 of clinical AD samples and subsequently identified a novel rare variant c.–2067A > C with watchable relevance (whereas the P-value was not significant after adjustment). Dual-luciferase assay showed that the variant sharply stimulated ADAMTS1 expression. In addition, ADAMTS1 was also clearly induced by pentylenetetrazol-ignited neuronal activity and enriched environment (EE). Inspired by the above findings, we investigated ADAMTS1’s role in APP metabolism in vitro and in vivo. Results showed that ADAMTS1 participated in APP hydrolysis and consequently decreased Aβ generation through inhibiting β-secretase-mediated cleavage. In addition, we also verified that the hippocampal amyloid load of AD mouse model was alleviated by the introduction of ADAMTS1, and thus spatial cognition was restored as well. This study revealed the contribution of ADAMTS1 to the connection of genetic and acquired factors with APP metabolism, and its potential in reducing hippocampal amyloid and consequent risk of AD.

Preliminary study of genome-wide association identifies novel susceptibility genes for serum mineral elements in the Chinese Han population

Mineral elements (copper (Cu), zinc (Zn), calcium (Ca), magnesium (Mg), iron (Fe)) play important biological roles in enzymes, hormones, vitamins, and normal metabolism. The deficiency of mineral elements can lead to abnormal physiological functions. And some elements (such as lead (Pb)) are harmful to the body. We aim to identify genetic loci which can influence the serum levels of mineral elements (Cu, Zn, Ca, Mg, Fe, and Pb). Genotyping was performed using Applied Biosystems Axiom™ PMDA in 587 individuals, and 6,423,076 single-nucleotide polymorphisms (SNPs) were available for the genome-wide association study (GWAS) analysis. The association between genotype and phenotype was analyzed using mixed linear regression (additive genetic model) adjusting by age and gender combined with identical by descent (IBD) matrix. Genetic loci in BCHE-LOC105374194, DTX2P1-UPK3BP1-PMS2P11, VAT1L, LINC00908-LINC00683, LINC01310-NONE, and rs6747410 in VWA3B were identified to be associated with serum Cu element concentration (p < 5 × 10^-6). ADAMTSL1 rs17229526 (p = 4.96 × 10^-6) was significantly associated with serum Zn element levels. Genetic loci in LRP1B, PIGZ-MELTF, LINC01365-LINC02502, and HAPLN3 were related to serum Ca element levels (p < 5 ×1 0^-6). Three SNPs in ALPK1, ASAP1-ADCY8 and IER3IP1-SKOR2 also achieved a significant association with Mg element levels (p < 5 × 10^-6). TACSTD2-MYSM1, LRP1B, and ASAP1-ADCY8 showed suggestive associations with serum Fe element levels (p < 5 × 10^-6). Moreover, the two most significant SNPs associated with Pb were rs304234 in CADPS-LINC00698 (p = 2.47 × 10^-6) and rs12666460 in LOC101928211-GPR37 (p = 1.81 × 10^-6). In summary, we reported 19 suggestive loci associated with serum mineral elements in the Chinese Han population. These findings provided new insights into the potential mechanisms regulating serum mineral elements levels.

Disintegrin and Metalloproteinases (ADAMs [A Disintegrin and Metalloproteinase] and ADAMTSs [ADAMs With a Thrombospondin Motif]) in Aortic Aneurysm

Aortic aneurysm is a complex pathology that can be lethal if not detected in time. Although several molecular mechanisms and pathways have been identified to be involved in aortic aneurysm development and growth, the current lack of an effective pharmacological treatment highlights the need for a more thorough understanding of the factors that regulate the remodeling of the aortic wall in response to triggers that lead to aneurysm formation. This task is further complicated by the regional heterogeneity of the aorta and that thoracic and abdominal aortic aneurysm are distinct pathologies with different risk factors and distinct course of progression. ADAMs (a disintegrin and metalloproteinases) and ADAMTS (ADAMs with a thrombospondin motif) are proteinases that share similarities with other proteinases but possess unique and diverse properties that place them in a category of their own. In this review, we discuss what is known on how ADAMs and ADAMTSs are altered in abdominal aortic aneurysm and thoracic aortic aneurysm in patients, in different animal models, and their role in regulating the function of different vascular and inflammatory cell types. A full understanding of the role of ADAMs and ADAMTSs in aortic aneurysm will help reveal a more complete understanding of the underlying mechanism driving aneurysm formation, which will help towards developing an effective treatment in preventing or limiting the growth of aortic aneurysm.

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.

Secretome of Adipose Tissue as the Key to Understanding the Endocrine Function of Adipose Tissue

The prevalence of obesity has reached pandemic levels and is becoming a serious health problem in developed and developing countries. Obesity is associated with an increased prevalence of comorbidities that include type II diabetes, cardiovascular diseases and some cancers. The recognition of adipose tissue as an endocrine organ capable of secreting adipokines that influence whole-body energy homeostasis was a breakthrough leading to a better molecular understanding of obesity. Of the adipokines known to be involved in the regulation of energy metabolism, very few are considered central regulators of insulin sensitivity, metabolism and energy homeostasis, and the discovery and characterization of new adipocyte-derived factors are still ongoing. Proteomics techniques, such as liquid chromatography-mass spectrometry or gas chromatography-mass spectrometry, have proven to be useful tools for analyzing the secretory function of adipose tissue (the secretome), providing insights into molecular events that influence body weight. Apart from the identification of novel proteins, the considerable advantage of this approach is the ability to detect post-translational modifications that cannot be predicted in genomic studies. In this review, we summarize recent efforts to identify novel bioactive secretory factors through proteomics.

ADAM and ADAMTS disintegrin and metalloproteinases as major factors and molecular targets in vascular malfunction and disease

A Disintegrin and Metalloproteinase (ADAM) and A Disintegrin and Metalloproteinase with Thrombospondin Motifs (ADAMTS) are two closely related families of proteolytic enzymes. ADAMs are largely membrane-bound enzymes that act as molecular scissors or sheddases of membrane-bound proteins, growth factors, cytokines, receptors and ligands, whereas ADAMTS are mainly secreted enzymes. ADAMs have a pro-domain, and a metalloproteinase, disintegrin, cysteine-rich and transmembrane domain. Similarly, ADAMTS family members have a pro-domain, and a metalloproteinase, disintegrin, and cysteine-rich domain, but instead of a transmembrane domain they have thrombospondin motifs. Most ADAMs and ADAMTS are activated by pro-protein convertases, and can be regulated by G-protein coupled receptor agonists, Ca²⁺ ionophores and protein kinase C. Activated ADAMs and ADAMTS participate in numerous vascular processes including angiogenesis, vascular smooth muscle cell proliferation and migration, vascular cell apoptosis, cell survival, tissue repair, and wound healing. ADAMs and ADAMTS also play a role in vascular malfunction and cardiovascular diseases such as hypertension, atherosclerosis, coronary artery disease, myocardial infarction, heart failure, peripheral artery disease, and vascular aneurysm. Decreased ADAMTS13 is involved in thrombotic thrombocytopenic purpura and microangiopathies. The activity of ADAMs and ADAMTS can be regulated by endogenous tissue inhibitors of metalloproteinases and other synthetic small molecule inhibitors. ADAMs and ADAMTS can be used as diagnostic biomarkers and molecular targets in cardiovascular disease, and modulators of ADAMs and ADAMTS activity may provide potential new approaches for the management of cardiovascular disorders.

Metalloproteases in gonad formation and ovulation

Changes in expression or activation of various metalloproteases including matrix metalloproteases (Mmp), a disintegrin and metalloprotease (Adam) and a disintegrin and metalloprotease with thrombospondin motif (Adamts), and their endogenous inhibitors (tissue inhibitors of metalloproteases, Timp), have been shown to be critical for ovulation in various species from studies in past decades. Some of these metalloproteases such as Adamts1, Adamts9, Mmp2, and Mmp9 have also been shown to be regulated by luteinizing hormone (LH) and/or progestin, which are essential triggers for ovulation in all vertebrate species. Most of these metalloproteases also express broadly in various tissues and cells including germ cells and somatic gonad cells. Thus, metalloproteases likely play roles in gonad formation processes comprising primordial germ cell (PGC) migration, development of germ and somatic cells, and sex determination. However, our knowledge on the functions and mechanisms of metalloproteases in these processes in vertebrates is still lacking. This review will summarize our current knowledge on the metalloproteases in ovulation and gonad formation with emphasis on PGC migration and germ cell development.

Identification of novel ADAMTS1, ADAMTS4 and ADAMTS5 cleavage sites in versican using a label-free quantitative proteomics approach

The chondroitin sulfate proteoglycan versican is important for embryonic development and several human disorders. The versican V1 splice isoform is widely expressed and cleaved by ADAMTS proteases at a well-characterized site, Glu441-Ala442. Since ADAMTS proteases cleave the homologous proteoglycan aggrecan at multiple sites, we hypothesized that additional cleavage sites existed within versican. We report a quantitative label-free approach that ranks abundance of liquid chromatography-tandem mass spectrometry (LC-MS/MS)-identified semi-tryptic peptides after versican digestion by ADAMTS1, ADAMTS4 and ADAMTS5 to identify site-specific cleavages. Recombinant purified versican V1 constructs were digested with the recombinant full-length proteases, using catalytically inactive mutant proteases in control digests. Semi-tryptic peptide abundance ratios determined by LC-MS/MS in ADAMTS:control digests were compared to the mean of all identified peptides to obtain a z-score by which outlier peptides were ranked, using semi-tryptic peptides identifying Glu441 -Ala442 cleavage as the benchmark. Tryptic peptides with higher abundance in control digests supported cleavage site identification. We identified several novel cleavage sites supporting the ADAMTS1/4/5 cleavage site preference for a P1-Glu residue in proteoglycan substrates. Digestion of proteins in vitro and application of this z-score approach is potentially widely applicable for mapping protease cleavage sites using label-free proteomics. SIGNIFICANCE: Versican abundance and turnover are relevant to the pathogenesis of several human disorders. Versican is cleaved by A Disintegrin-like And Metalloprotease with Thrombospondin type 1 motifs (ADAMTS) family members at Glu441-Ala442, generating a bioactive proteoform called versikine, but additional cleavage sites and the site-specificity of individual ADAMTS proteases is unexplored. Here, we used a label-free proteomics strategy to identify versican cleavage sites for 3 ADAMTS proteases, applying a novel z-score-based statistical approach to compare the protease digests of versican to controls (digests with inactive protease) using the known protease cleavage site as a benchmark. We identified 21 novel cleavage sites that had a comparable z-score to the benchmark. Given the functional significance of versikine, they represent potentially significant cleavages and helped to refine a substrate site preference for each protease.The z-score approach is potentially widely applicable for discovery of site-specific cleavages within an purified protein or small ensemble of proteins using any protease.

Osteoblasts Regulate the Expression of ADAMTS and MMPs in Chondrocytes through ERK Signaling Pathway

OBJECTIVE

Degradative enzymes such as matrix metalloproteinase (MMP) and disintegrin metalloproteinase with platelet thrombin-sensitive protein-like motifs (ADAMTS) play a key role in the development of osteoarthritis (OA). We aimed to investigate the effects of OA subchondral osteoblasts on the expression of ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 in chondrocytes and the regulation of mitogen-activated protein kinase (MAPK) signaling pathway.

METHODS

A rat knee OA model was constructed by cutting the anterior cruciate ligament of the knee joints, and normal rat articular cartilage chondrocytes (N-ACC), OA rat articular cartilage chondrocytes (O-ACC), normal subchondral bone osteoblasts (N-SBO), and OA subchondral bone osteoblasts (O-SBO) were isolated and extracted. The expressions of O-ACC and O-SBO COL1 and COL2 were detected respectively. Chondrocytes were identified by immunofluorescence of COL2 and toluidine blue staining, and osteoblasts were identified by COL1 immunofluorescence, alkaline phosphatase (ALP), and Alizarin Red staining. Gene expression of COL1, COL2, and aggrecan in normal chondrocytes and OA chondrocytes, and gene expression of osteoblast ALP and osteocalcin (OCN) were detected by RT-PCR to identify the two chondrocytes and the two osteoblast phenotypes. The constructing N-ACC group, O-ACC group, N-ACC + N-SBO group, N-ACC + O-SBO group, O-ACC + N-SBO group, O-ACC + O-SBO group, I + N-ACC + O-SBO group, and I + O-ACC + O-SBO group cell cultures, and the expression of ERK, ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 genes in chondrocytes cultured for 0, 24, 48, and 72 h were detected by RT-PCR. The protein expressions of pERK, ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 were detected by Western blot.

RESULTS

· The X-ray showed that the knee joint space of the affected limb became narrow.. · The results of RT-PCR of COL2 and aggrecan gene in OA and normal chondrocytes suggest that the relative expression of COL2 in OA articular chondrocytes (0.24 ± 0.07) is significantly lower than that in normal cartilage (0.61 ± 0.07) (p < 0.05). The relative expression of AGG (0.37 ± 0.16) in OA chondrocytes was significantly lower than that of normal chondrocytes AGG (1.30 ± 0.25) (p < 0.05). The expression of COL1 was very low, and was not statistically significant.. · The results of RT-PCR of the osteoblast ALP and OCN gene indicated that gene expression of ALP (12.30 ± 1.17) and OCN (20.47 ± 4.19)was upregulated when compared with the relative expression of ALP (4.66 ± 0.71) (p < 0.05) and OCN (12.17 ± 2.76) (p < 0.05) in normal osteoblasts, indicating that osteoblasts of OA have greater osteogenic potential than normal osteoblasts.. · The expressions of ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 genes and proteins in OA chondrocytes or normal chondrocytes were basically unchanged when they were cocultured with normal osteoblasts. Indirect coculture of OA osteoblasts and chondrocytes could promote the expression of ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 genes and proteins in chondrocytes. Overexpression of ADAMTS and MMP in coculture systems can be reversed by MAPK-ERK inhibitors..

CONCLUSIONS

· OA subchondral bone osteoblasts can promote the overexpression of ADAMTS and MMPs in chondrocytes.. · The ERK signaling pathway may be involved in the regulation of the effect of subchondral bone osteoblasts on chondrocytes..

An anti-ADAMTS1 treatment relieved muscle dysfunction and fibrosis in dystrophic mice

Duchenne Muscular Dystrophy (DMD) is caused by mutations in the dystrophin gene, accompanied by aberrant extracellular matrix synthesis and muscle damage. ADAMTS1 metalloproteinase was reported increased in dystrophin-deficient mdx mouse. The aim of this study was to explore the role of ADAMTS1 in muscle function, fibrosis and damage, and respiratory function of mdx mice. 102 DMD patients and their mothers were included in this study. Multiplex ligation dependent probe amplification (MLPA) assay and Next-generation sequencing (NGS) were adopted to do genetic diagnosis. Dystrophin-deficient mdx mice were treated with anti-ADAMTS1 antibody (anti-ADAMTS1) for three weeks. The results showed that ADAMTS1 was increased in gastrocnemius muscle of mdx mice and serum of DMD patients. Anti-ADAMTS1 treatment increased Versican transcription but suppressed versican protein expression. Besides, we found anti-ADAMTS1 improved muscle strength, diaphragm and extensor digitorum longus muscles functions in mdx mice. Meanwhile, muscle fibrosis and damage were attenuated in anti-ADAMTS1 treated dystrophic mice. In summary, anti-ADAMTS1 antibody relieved muscle dysfunction and fibrosis in dystrophic mice. It is suggested that ADAMTS1 is a potential target for developing new biological therapies for DMD.

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.

Metalloprotease ADAMTS-1 decreases cell migration and invasion modulating the spatiotemporal dynamics of Cdc42 activity

ADAMTSs (A Disintegrin And Metalloproteinase with ThromboSpondin motifs) are secreted proteases dependent on Zn2+/Ca2+, involved in physiological and pathological processes and are part of the extracellular matrix (ECM). Here, we investigated if ADAMTS-1 is required for invasion and migration of cells and the possible mechanism involved. In order to test ADAMTS-1's role in ovarian cancer cells (CHO, NIH-OVCAR-3 and ES2) and NIH-3 T3 fibroblasts, we modified the levels of ADAMTS-1 and compared those to parental. Cells exposed to ADAMTS-1-enriched medium exhibited a decline in cell migration and invasion when compared to controls with or without a functional metalloproteinase domain. The opposite was observed in cells when ADAMTS-1 was deleted via the CRISPR/Cas9 approach. The decline in ADAMTS-1 levels enhanced the phosphorylated form of Src and FAK. We also evaluated the activities of cellular Rho GTPases from cell lysates using the GLISA® kit. The Cdc42-GTP signal was significantly increased in the CRISPR ADAMTS-1 ES-2 cells. By a Förster resonance energy transfer (FRET) biosensor for Cdc42 activity in ES-2 cells we demonstrated that Cdc42 activity was strongly polarized at the leading edge of migrating cells with ADAMTS-1 deletion, compared to the wild type cells. As conclusion, ADAMTS-1 inhibits proliferation, polarization and migration.

Polymorphisms in the ASMT and ADAMTS1 gene may increase litter size in goats

Prolificacy of most local goat breeds in China is low. Jining Grey goat is one of the most prolific goat breeds in China, it is an important goat breed for the rural economy. ASMT (acetylserotonin O‐methyltransferase) and ADAMTS1 (ADAM metallopeptidase with thrombospondin type 1 motif) are essential for animal reproduction. Single nucleotide polymorphisms (SNPs) of ASMT and ADAMTS1 genes in the highly prolific breed (Jining Grey goats), medium prolific breed (Boer goats and Guizhou White goats) and low prolific breeds (Angora goats, Liaoning Cashmere goats and Inner Mongolia Cashmere goats) were detected by polymerase chain reaction‐restriction fragment length polymorphism and sequencing. Two SNPs (g.158122T>C, g.158700G>A) of ASMT gene and two SNPs (g.7979798A>G, g.7979477C>T) of ADAMTS1 gene were identified. For g.158122T>C of ASMT gene, further analysis revealed that genotype TC or CC had 0.66 (p < 0.05) or 0.75 (p < 0.05) kids more than those with genotype TT in Jining Grey goats. No significant difference (p > 0.05) was found in litter size between TC and CC genotypes. The SNP (g.158122T>C) caused a p.Tyr298His change and this SNP mutation resulted in changes in protein binding sites and macromolecule‐binding sites. The improvement in reproductive performance may be due to changes in the structure of ASMT protein. For g.7979477C>T of ADAMTS1 gene, Jining Grey does with genotype CT or TT had 0.82 (p < 0.05) or 0.86 (p < 0.05) more kids than those with genotype CC. No significant difference (p > 0.05) was found in litter size between CT or TT genotypes. These results preliminarily indicated that C allele (g.158122T>C) of ASMT gene and T allele (g.7979477C>T) of ADAMTS1 gene are potential molecular markers which could improve litter size of Jining Grey goats and be used in goat breeding.

ADAMTS-5: A difficult teenager turning 20

A Disintegrin And Metalloproteinase with ThromboSpondin motif (ADAMTS)-5 was identified in 1999 as one of the enzymes responsible for cleaving aggrecan, the major proteoglycan in articular cartilage. Studies in vitro, ex vivo and in vivo have validated ADAMTS-5 as a target in osteoarthritis (OA), a disease characterized by extensive degradation of aggrecan. For this reason, it attracted the interest of many research groups aiming to develop a therapeutic treatment for OA patients. However, ADAMTS-5 proteoglycanase activity is not only involved in the dysregulated aggrecan proteolysis, which occurs in OA, but also in the physiological turnover of other related proteoglycans. In particular, versican, a major ADAMTS-5 substrate, plays an important structural role in heart and blood vessels and its proteolytic processing by ADAMTS-5 must be tightly regulated. On the occasion of the 20th anniversary of the discovery of ADAMTS-5, this review looks at the evidence for its detrimental role in OA, as well as its physiological turnover of cardiovascular proteoglycans. Moreover, the other potential functions of this enzyme are highlighted. Finally, challenges and emerging trends in ADAMTS-5 research are discussed.

Underestimated Aspect of Mucopolysaccharidosis Pathogenesis: Global Changes in Cellular Processes Revealed by Transcriptomic Studies

Mucopolysaccharidoses (MPS), a group of inherited metabolic disorders caused by deficiency in enzymes involved in degradation of glycosaminoglycans (GAGs), are examples (and models) of monogenic diseases. Accumulation of undegraded GAGs in lysosomes was supposed to be the major cause of MPS symptoms; however, their complexity and variability between particular types of the disease can be hardly explained by such a simple storage mechanism. Here we show that transcriptomic (RNA-seq) analysis of the material derived from fibroblasts of patients suffering from all types and subtypes of MPS, supported by RT-qPCR results, revealed surprisingly large changes in expression of genes involved in various cellular processes, indicating complex mechanisms of MPS. Although each MPS type and subtype was characterized by specific changes in gene expression profile, there were genes with significantly changed expression relative to wild-type cells that could be classified as common for various MPS types, suggesting similar disturbances in cellular processes. Therefore, both common features of all MPS types, and differences between them, might be potentially explained on the basis of changes in certain cellular processes arising from disturbed regulations of genes’ expression. These results may shed a new light on the mechanisms of genetic diseases, indicating how a single mutation can result in complex pathomechanism, due to perturbations in the network of cellular reactions. Moreover, they should be considered in studies on development of novel therapies, suggesting also why currently available treatment methods fail to correct all/most symptoms of MPS. We propose a hypothesis that disturbances in some cellular processes cannot be corrected by simple reduction of GAG levels; thus, combined therapies are necessary which may require improvement of these processes.

Glucose Restriction Plus Refeeding in Vitro Induce Changes of the Human Adipocyte Secretome with an Impact on Complement Factors and Cathepsins

Adipose tissue is a major endocrine organ capable of secreting adipokines with a role in whole-body metabolism. Changes in the secretome profile during the development of obesity is suspected to contribute to the risk of health complications such as those associated with weight regain after weight loss. However, the number of studies on weight regain is limited and secretome changes during weight regain have hardly been investigated. In an attempt to generate leads for in vivo studies, we have subjected human Simpson Golabi Behmel Syndrome adipocytes to glucose restriction (GR) followed by refeeding (RF) as an in vitro surrogate for weight regain after weight loss. Using LC-MS/MS, we compared the secreted protein profile after GR plus RF with that of normal feeding (NF) to assess the consequences of GR plus RF. We identified 338 secreted proteins of which 49 were described for the first time as being secreted by adipocytes. In addition, comparison between NF and GR plus RF showed 39 differentially secreted proteins. Functional classification revealed GR plus RF-induced changes of enzymes for extracellular matrix modification, complement system factors, cathepsins, and several proteins related to Alzheimer’s disease. These observations can be used as clues to investigate metabolic consequences of weight regain, weight cycling or intermittent fasting.

TIMP-3 as a therapeutic target for cancer

Tissue inhibitor of metalloproteinase-3 (TIMP-3), a secreted glycoprotein, plays an important role in carcinogenesis. It can bind to many proteinases to suppress their activity and thus protect the extracellular matrix from degradation. TIMP-3 may have many anticancer properties, including apoptosis induction and antiproliferative, antiangiogenic, and antimetastatic activities. This review summarizes the structure, proteinase inhibition ability, genetic and epigenetic regulation, cancer therapy potential, and contribution to cancer development of TIMP-3. Furthermore, in this review we discuss its potential as a biomarker for predicting cancer progression and the current state of drugs that target TIMP-3, either alone or in combination with clinical treatment. In conclusion, TIMP-3 can be a biomarker of cancer and a potential target for cancer therapy. This review article can serve as a basis to understand how to modulate TIMP-3 levels as a drug target of cancers.

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.

Ovulation: Parallels With Inflammatory Processes

The midcycle surge of LH sets in motion interconnected networks of signaling cascades to bring about rupture of the follicle and release of the oocyte during ovulation. Many mediators of these LH-induced signaling cascades are associated with inflammation, leading to the postulate that ovulation is similar to an inflammatory response. First responders to the LH surge are granulosa and theca cells, which produce steroids, prostaglandins, chemokines, and cytokines, which are also mediators of inflammatory processes. These mediators, in turn, activate both nonimmune ovarian cells as well as resident immune cells within the ovary; additional immune cells are also attracted to the ovary. Collectively, these cells regulate proteolytic pathways to reorganize the follicular stroma, disrupt the granulosa cell basal lamina, and facilitate invasion of vascular endothelial cells. LH-induced mediators initiate cumulus expansion and cumulus oocyte complex detachment, whereas the follicular apex undergoes extensive extracellular matrix remodeling and a loss of the surface epithelium. The remainder of the follicle undergoes rapid angiogenesis and functional differentiation of granulosa and theca cells. Ultimately, these functional and structural changes culminate in follicular rupture and oocyte release. Throughout the ovulatory process, the importance of inflammatory responses is highlighted by the commonalities and similarities between many of these events associated with ovulation and inflammation. However, ovulation includes processes that are distinct from inflammation, such as regulation of steroid action, oocyte maturation, and the eventual release of the oocyte. This review focuses on the commonalities between inflammatory responses and the process of ovulation.

A Disintegrin and Metalloproteinase (ADAM) and ADAM with thrombospondin motifs (ADAMTS) family in vascular biology and disease

A Disintegrin and Metalloproteinase (ADAM) is a family of proteolytic enzymes that possess sheddase function and regulate shedding of membrane-bound proteins, growth factors, cytokines, ligands and receptors. Typically, ADAMs have a pro-domain, and a metalloproteinase, disintegrin, cysteine-rich and a characteristic transmembrane domain. Most ADAMs are activated by proprotein convertases, but can also be regulated by G-protein coupled receptor agonists, Ca²⁺ ionophores and protein kinase C activators. A Disintegrin and Metalloproteinase with Thrombospondin Motifs (ADAMTS) is a family of secreted enzymes closely related to ADAMs. Like ADAMs, ADAMTS members have a pro-domain, and a metalloproteinase, disintegrin, and cysteine-rich domain, but they lack a transmembrane domain and instead have characteristic thrombospondin motifs. Activated ADAMs perform several functions and participate in multiple cardiovascular processes including vascular smooth muscle cell proliferation and migration, angiogenesis, vascular cell apoptosis, cell survival, tissue repair, and wound healing. ADAMs may also be involved in pathological conditions and cardiovascular diseases such as atherosclerosis, hypertension, aneurysm, coronary artery disease, myocardial infarction and heart failure. Like ADAMs, ADAMTS have a wide-spectrum role in vascular biology and cardiovascular pathophysiology. ADAMs and ADAMTS activity is naturally controlled by endogenous inhibitors such as tissue inhibitors of metalloproteinases (TIMPs), and their activity can also be suppressed by synthetic small molecule inhibitors. ADAMs and ADAMTS can serve as important diagnostic biomarkers and potential therapeutic targets for cardiovascular disorders. Natural and synthetic inhibitors of ADAMs and ADAMTS could be potential therapeutic tools for the management of cardiovascular diseases.

The role of ADAMTS genes in the end stage of hip osteoarthritis

PURPOSE

The aim of this study is to investigate which ADAMTS genes play a major role in the development of primary hip osteoarthritis, by comparing the tissue and blood samples in patients with hip osteoarthritis and a control group.

MATERIAL AND METHODS

Human articular cartilage was obtained from femoral heads of 15 patients with end stage osteoarthritis undergoing total hip replacement. As the control group, the cartilages was obtained from femoral heads of 15 patients, who did not have osteoarthritis or degenerative changes in hip joint, undergoing hip replacement following the fracture of the femoral neck. After the cartilage samples were taken from the resection materials, the DNA polymorphisms in the patients' cartilage samples were tested by Polymerase Chain Reaction (PCR), the serum levels of aggrecanase genes were analyzed with Enzyme-Linked ImmunoSorbent Assay (ELISA).

RESULTS

The level of ADAMTS5 and ADAMTS9 genes were found significantly lower as a result of ELISA analysis degenerative arthritis group than the control group (p < 0,05). ADAMTS 1, 4, 8, 15 were similar between the two groups in ELISA analysis (p > 0,05). As a result of quantitative real time RT-PCR analysis, the level of ADAMTS8 mRNA increased 3.5 fold in hip degenerative arthritis group when compared with femoral neck fractures group. ADAMTS1, ADAMTS4 and ADAMTS5 expression levels in hip degenerative arthritis group were decreased 2.5, 2 and 2.5 fold, respectively. ADAMTS9, 15 were found to be similar between two groups.

CONCLUSON

As a result of this study on hip osteoarthritis, the ADAMTS8 levels was found to be significantly higher in the end stage of hip osteoarthritis. Unlike similar studies on knee osteoarthritis, ADAMTS1,4,5 levels were found to be lower.

ADAMTS1 protease is required for a balanced immune cell repertoire and tumour inflammatory response

Recent advances have emphasized the relevance of studying the extracellular microenvironment given its main contribution to tissue homeostasis and disease. Within this complex scenario, we have studied the extracellular protease ADAMTS1 (a disintegrin and metalloprotease with thrombospondin motif 1), implicated in vascularization and development, with reported anti- and pro-tumorigenic activities. In this work we performed a detailed study of the vasculature and substrates in adult organs of wild type and Adamts1-deficient mice. In addition to the expected alterations of organs like kidney, heart and aorta, we found that the lack of ADAMTS1 differently affects lymphocyte and myeloid populations in the spleen and bone marrow. The study of the substrate versican also revealed its alteration in the absence of the protease. With such premises, we challenged our mice with subcutaneous B16F1 syngeneic tumours and closely evaluated the immune repertoire in the tumours but also in the distant spleen and bone marrow. Our results confirmed a pro-inflammatory landscape in the absence of ADAMTS1, correlating with tumour blockade, supporting its novel role as a modulator of the immune cell response.

Keratan sulfate, a complex glycosaminoglycan with unique functional capability

From an evolutionary perspective keratan sulfate (KS) is the newest glycosaminoglycan (GAG) but the least understood. KS is a sophisticated molecule with a diverse structure, and unique functional roles continue to be uncovered for this GAG. The cornea is the richest tissue source of KS in the human body but the central and peripheral nervous systems also contain significant levels of KS and a diverse range of KS-proteoglycans with essential functional roles. KS also displays important cell regulatory properties in epithelial and mesenchymal tissues and in bone and in tumor development of diagnostic and prognostic utility. Corneal KS-I displays variable degrees of sulfation along the KS chain ranging from non-sulfated polylactosamine, mono-sulfated and disulfated disaccharide regions. Skeletal KS-II is almost completely sulfated consisting of disulfated disaccharides interrupted by occasional mono-sulfated N-acetyllactosamine residues. KS-III also contains highly sulfated KS disaccharides but differs from KS-I and KS-II through 2-O-mannose linkage to serine or threonine core protein residues on proteoglycans such as phosphacan and abakan in brain tissue. Historically, the major emphasis on the biology of KS has focused on its sulfated regions for good reason. The sulfation motifs on KS convey important molecular recognition information and direct cell behavior through a number of interactive proteins. Emerging evidence also suggest functional roles for the poly-N-acetyllactosamine regions of KS requiring further investigation. Thus further research is warranted to better understand the complexities of KS.

The Many Facets of Metzincins and Their Endogenous Inhibitors: Perspectives on Ovarian Cancer Progression

Approximately sixty per cent of ovarian cancer patients die within the first five years of diagnosis due to recurrence associated with chemoresistance. The metzincin family of metalloproteinases is enzymes involved in matrix remodeling in response to normal physiological changes and diseased states. Recently, there has been a mounting awareness of these proteinases and their endogenous inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), as superb modulators of cellular communication and signaling regulating key biological processes in cancer progression. This review investigates the role of metzincins and their inhibitors in ovarian cancer. We propose that understanding the metzincins and TIMP biology in ovarian cancer may provide valuable insights in combating ovarian cancer progression and chemoresistance-mediated recurrence in patients.

Histone deacetylase-4 and histone deacetylase-8 regulate interleukin-1β-induced cartilage catabolic degradation through MAPK/JNK and ERK pathways

Interleukin-1β (IL-1β)-induced inflammatory response is associated with osteoarthritis (OA) and its development. Histone deacetylase (HDAC) may be involved in regulating this pathogenesis, but the mechanism has yet to be elucidated. The aim of the present study was to investigate the mechanism underlying the regulation of IL-1β-stimulated catabolic degradation of cartilage by HDAC. An in vitro model of OA was generated using rat articular chondrocytes (rACs) treated with IL-1β. The role of HDAC in IL-1β-induced gene expression was investigated using HDAC inhibitors and specific small interfering RNAs (siRNAs). The association of diverse mitogen-activated protein kinase (MAPK) pathways was examined. The IL-1β-induced expression of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4 and ADAMTS-5, and the production of collagen X and cyclo-oxygenase-2 in rACs was accompanied by the expression of HDAC4 and HDAC8, and were significantly downregulated by HDAC inhibitors and specific siRNAs. IL-1β-induced activation of extracellular signal-regulated kinase was downregulated by the HDAC inhibitor Trichostatin A, but not significantly by PCI-34051. The activation of c-Jun N-terminal kinase was observably downregulated by the latter, but only slightly by the former. These results suggest that HDAC4 and HDAC8 may serve as key upstream mediators of MAPK in regulating the IL-1β-induced cartilage catabolic and degradation. Therefore, inhibiting HDAC4 or HDAC8 or both may be a promising therapeutic strategy in preventing and treating OA.

Stroma-derived but not tumor ADAMTS1 is a main driver of tumor growth and metastasis

The matrix metalloprotease ADAMTS1 (A Disintegrin And Metalloprotease with ThromboSpondin repeats 1) has been involved in tumorigenesis although its contributions appeared ambiguous. To understand the multifaceted actions of this protease, it is still required a deeper knowledge of its implication in heterogeneous tumor-stroma interactions. Using a syngeneic B16F1 melanoma model in wild type and ADAMTS1 knockout mice we found distinct stroma versus tumor functions for this protease. Genetic deletion of ADAMTS1 in the host microenvironment resulted in a drastic decrease of tumor growth and metastasis. However, the downregulation of tumor ADAMTS1 did not uncover relevant effects. Reduced tumors in ADAMTS1 KO mice displayed a paradoxical increase in vascular density and vascular-related genes; a detailed characterization revealed an impaired vasculature, along with a minor infiltration of macrophages. In addition, ex-vivo assays supported a chief role for ADAMTS1 in vascular sprouting, and melanoma xenografts showed a relevant induction of its expression in stroma compartments. These findings provide the first genetic evidence that supports the pro-tumorigenic role of stromal ADAMTS1.

Matrix Metalloproteinases, Vascular Remodeling, and Vascular Disease

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that degrade various proteins in the extracellular matrix (ECM). Typically, MMPs have a propeptide sequence, a catalytic metalloproteinase domain with catalytic zinc, a hinge region or linker peptide, and a hemopexin domain. MMPs are commonly classified on the basis of their substrates and the organization of their structural domains into collagenases, gelatinases, stromelysins, matrilysins, membrane-type (MT)-MMPs, and other MMPs. MMPs are secreted by many cells including fibroblasts, vascular smooth muscle (VSM), and leukocytes. MMPs are regulated at the level of mRNA expression and by activation through removal of the propeptide domain from their latent zymogen form. MMPs are often secreted in an inactive proMMP form, which is cleaved to the active form by various proteinases including other MMPs. MMPs degrade various protein substrates in ECM including collagen and elastin. MMPs could also influence endothelial cell function as well as VSM cell migration, proliferation, Ca²⁺ signaling, and contraction. MMPs play a role in vascular tissue remodeling during various biological processes such as angiogenesis, embryogenesis, morphogenesis, and wound repair. Alterations in specific MMPs could influence arterial remodeling and lead to various pathological disorders such as hypertension, preeclampsia, atherosclerosis, aneurysm formation, as well as excessive venous dilation and lower extremity venous disease. MMPs are often regulated by endogenous tissue inhibitors of metalloproteinases (TIMPs), and the MMP/TIMP ratio often determines the extent of ECM protein degradation and tissue remodeling. MMPs may serve as biomarkers and potential therapeutic targets for certain vascular disorders.

MiR-362-3p inhibits the proliferation and migration of vascular smooth muscle cells in atherosclerosis by targeting ADAMTS1

Atherosclerosis is a progressive condition of the large arteries that can cause coronary artery disease (CAD). Growing amounts of evidence have indicated that microRNAs (miRNAs, miRs) can be used as diagnostic biomarkers in many cellular processes associated with CAD. MiR-362-3p has been implicated in many biological cellular functions. However, little is known about the role of miR-362-3p during atherosclerosis. In the present study, significant downregulation of miR-362-3p was observed in 110 atherosclerotic CAD patients and not in the 84 controls. The upregulation of miR-362-3p was demonstrated to inhibit vascular smooth muscle cell (VSMC) proliferation and migration, and impede the G1/S cell cycle transition. Bioinformatics analysis indicated that a disintegrin and metalloproteinase with thrombospondin motifs 1 (ADAMTS1) was a direct target of miR-362-3p. Subsequent experiments demonstrated that miR-362-3p binds to the 3'-untranslated region (UTR) of ADAMTS1 and decreases its levels of mRNA and protein expression. Overexpression of ADAMTS1 partially restored the miR-362-3p-mediated inhibition of VSMC proliferation, cell cycle, and migration. Upregulation of ADAMTS1 in plasma samples was detected in atherosclerotic CAD patients. Taken together, our findings suggested that miR-362-3p inhibits the proliferation and migration of VSMCs by directly targeting ADAMTS1, which might provide novel insight into the molecular mechanisms underlying the action of miR-362-3p in atherosclerosis.

The extracellular metalloprotease AdamTS-A anchors neural lineages in place within and preserves the architecture of the central nervous system

The extracellular matrix (ECM) regulates cell migration and sculpts organ shape. AdamTS proteins are extracellular metalloproteases known to modify ECM proteins and promote cell migration, but demonstrated roles for AdamTS proteins in regulating CNS structure and ensuring cell lineages remain fixed in place have not been uncovered. Using forward genetic approaches in Drosophila, we find that reduction of AdamTS-A function induces both the mass exodus of neural lineages out of the CNS and drastic perturbations to CNS structure. Expressed and active in surface glia, AdamTS-A acts in parallel to perlecan and in opposition to viking/collagen IV and βPS-integrin to keep CNS lineages rooted in place and to preserve the structural integrity of the CNS. viking/collagen IV and βPS-integrin are known to promote tissue stiffness and oppose the function of perlecan, which reduces tissue stiffness. Our work supports a model in which AdamTS-A anchors cells in place and preserves CNS architecture by reducing tissue stiffness.

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.

Oocyte-specific deletion of furin leads to female infertility by causing early secondary follicle arrest in mice

The process of follicular development involves communications between oocyte and surrounding granulosa cells. FURIN is a member of the family of proprotein convertases that is involved in the activation of a large number of zymogens and proproteins by cleavage at its recognition motif. To investigate the functions of FURIN in female fertility, furin^flox/flox (fur^fl/fl) mice were crossed with Zp3-Cre mice and Gdf9-Cre, respectively, to achieve oocyte-specific disruption of FURIN. Here we report for the first time that FURIN is dispensable for primordial follicle maintenance and activation but important for early secondary follicular development, as ablation of FURIN in oocytes caused failure of follicle development beyond the type 4 and/or 5a follicles in mutant mice, resulting in increased number of early secondary follicles and the severely decreased number of mature follicles, thus anovulation and infertility. We also found that the developmental arrest of early secondary follicles might be rooted in the loss of the mature form of ADAMTS1 (85-kDa prodomain truncated) and compromised proliferation of granulosa cells in mutant mice. Taken together, our data highlight the importance of FURIN in follicle development beyond the early secondary follicle stage and indicate that compromised FURIN function leads to follicular dysplasia and female infertility in mice.

siRNA-knockdown of ADAMTS-13 modulates endothelial cell angiogenesis

ADAMTS-13, a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13, is a zinc-containing metalloprotease that cleaves von Willebrand factor (vWf). Previous publications by our laboratory have shown that ADAMTS-13 may also be involved in angiogenesis. For this study, we report the successful transient knockdown of endogenous ADAMTS-13 in human umbilical vein endothelial cells (HUVEC) via siRNA and the effects of reduced endogenous ADAMTS-13 on HUVEC angiogenesis functions. 15nM of ADAMTS-13 siRNA reduced HUVEC ADAMTS-13 protein levels by 90% after 24h incubation, whereas control siRNA did not affect endogenous ADAMTS-13 levels. Furthermore, this transfection did not affect the HUVEC endogenous protein level of ADAMTS-1, a related family member of ADAMTS-13 indicating the specificity of the siRNA. Transfection of HUVEC with 15nM of ADAMTS-13 siRNA resulted in a 21% decrease in proliferation after 24h incubation. The effects of ADAMTS-13 knockdown on migration of HUVEC across a scratch wound were also evaluated. 24h after transfection with control siRNA, there was increased cell migration across the scratch wound. This dramatic migration did not occur with ADAMTS-13 knockdown cells. Decreased protein levels of endogenous ADAMTS-13 also affected angiogenesis as measured by endothelial cell tube formation using a Matrigel matrix method. The tube lengths, sizes and junction numbers of the ADAMTS-13 knockdown cells were all significantly lower compared to control cells by about 40%. The protein level of vascular endothelial growth factor (VEGF), a well-known regulator of angiogenesis, was significantly decreased by 45% upon knockdown of ADAMTS-13. Moreover, activity of the AKT pathway, one of the VEGF angiogenesis downstream signaling pathways was down-regulated by ADAMTS-13 siRNA. These data indicate that in cultured endothelial cells, one role of endogenous ADAMTS-13 is regulation of angiogenesis, mediated through VEGF and AKT signaling pathway. Overall, our data suggest an additional model of endogenous ADAMTS-13 functionality, beyond that of cleaving von Willebrand factor.

Matrix Metalloproteinase Inhibitors as Investigational and Therapeutic Tools in Unrestrained Tissue Remodeling and Pathological Disorders

Matrix metalloproteinases (MMPs) are zinc-dependent proteolytic enzymes that degrade various proteins in the extracellular matrix (ECM). MMPs may also regulate the activity of membrane receptors and postreceptor signaling mechanisms and thereby affect cell function. The MMP family includes collagenases, gelatinases, stromelysins, matrilysins, membrane-type MMPs, and other MMPs. Inactive proMMPs are cleaved by other MMPs or proteases into active MMPs, which interact with various protein substrates in ECM and cell surface. MMPs regulate important biological processes such as vascular remodeling and angiogenesis and may be involved in the pathogenesis of cardiovascular disorders such as hypertension, atherosclerosis, and aneurysm. The role of MMPs is often assessed by measuring their mRNA expression, protein levels, and proteolytic activity using gel zymography. MMP inhibitors are also used to assess the role of MMPs in different biological processes and pathological conditions. MMP activity is regulated by endogenous tissue inhibitors of metalloproteinases (TIMPs), and the MMP/TIMP balance could determine the net MMP activity, ECM turnover, and tissue remodeling. Also, several synthetic MMP inhibitors have been developed. Synthetic MMP inhibitors include a large number of zinc-binding globulins (ZBGs), in addition to non-ZBGs and mechanism-based inhibitors. MMP inhibitors have been proposed as potential tools in the management of osteoarthritis, cancer, and cardiovascular disorders. However, most MMP inhibitors have broad-spectrum actions on multiple MMPs and could cause undesirable musculoskeletal side effects. Currently, doxycycline is the only MMP inhibitor approved by the Food and Drug Administration. New generation biological and synthetic MMP inhibitors may show greater MMP specificity and fewer side effects and could be useful in targeting specific MMPs, reducing unrestrained tissue remodeling, and the management of MMP-related pathological disorders.

Expression of a metalloproteinase family of ADAMTS in human vulnerable carotid lesions

AIMS

ADAMTS family of metalloproteases (a disintegrin and metalloprotease with thrombospondin motifs) possesses high proteolytic activity especially regarding proteoglycans. Their expression pattern in carotid plaques is as-yet unknown. The aim of the study was therefore the analysis of expression of ADAMTS1, 4, 5, and 13 and their inhibitors TIMP-1 and TIMP-3 in stable and unstable carotid plaques.

METHODS

Atherosclerotic plaques were collected from 40 patients (29 men, 11 women, mean age 70 years) undergoing carotid endarterectomy. The specimens were categorized into two groups (stable/unstable) according to Redgrave und Rothwell (The Oxford Plaque Study, 2008). SYBR Green-based real-time PCR, histology, and immunohistochemistry were performed.

RESULTS

All ADAMTS tested in our study were expressed in both stable and unstable plaques, especially in smooth muscle cells (SMCs) and macrophages. Analysis of the expression pattern on mRNA level showed significant higher expression of ADAMTS1 in unstable plaques compared with stable plaques (1.7-fold, P = 0.049). The expression of ADAMTS4 and 5 was also increased in unstable lesions; however, these changes were not statistically significant (1.2-fold, P = 0.667 and 1.6-fold, P = 0.077). Expression of TIMP-1 was significantly reduced in unstable plaques compared with stable ones (1.9-fold, P = 0.014).

CONCLUSION

SMCs seem to be an important source of ADAMTS analyzed in our study. Furthermore, expression of ADAMTS1 was found to be increased in unstable carotid lesions and might potentially contribute to plaque vulnerability.

Unusual life cycle and impact on microfibril assembly of ADAMTS17, a secreted metalloprotease mutated in genetic eye disease

Secreted metalloproteases have diverse roles in the formation, remodeling, and the destruction of extracellular matrix. Recessive mutations in the secreted metalloprotease ADAMTS17 cause ectopia lentis and short stature in humans with Weill-Marchesani-like syndrome and primary open angle glaucoma and ectopia lentis in dogs. Little is known about this protease or its connection to fibrillin microfibrils, whose major component, fibrillin-1, is genetically associated with ectopia lentis and alterations in height. Fibrillin microfibrils form the ocular zonule and are present in the drainage apparatus of the eye. We show that recombinant ADAMTS17 has unique characteristics and an unusual life cycle. It undergoes rapid autocatalytic processing in trans after its secretion from cells. Secretion of ADAMTS17 requires O-fucosylation and its autocatalytic activity does not depend on propeptide processing by furin. ADAMTS17 binds recombinant fibrillin-2 but not fibrillin-1 and does not cleave either. It colocalizes to fibrillin-1 containing microfibrils in cultured fibroblasts and suppresses fibrillin-2 (FBN2) incorporation in microfibrils, in part by transcriptional downregulation of Fbn2 mRNA expression. RNA in situ hybridization detected Adamts17 expression in specific structures in the eye, skeleton and other organs, where it may regulate the fibrillin isoform composition of microfibrils.

Hampered cumulus expansion of porcine cumulus-oocyte complexes by excessive presence of alpha2 -macroglobulin is likely mediated via inhibition of zinc-dependent metalloproteases

In vitro maturation (IVM) in serum causes hampered expansion of porcine cumulus-oocyte complexes (COCs) due to excessive alpha₂ -macroglobulin (A2M). This study investigated two hypotheses that could explain the effect of A2M: (i) binding of epidermal growth factor (EGF) to A2M, followed by its decreased availability; and (ii) inhibition of zinc-dependent metalloproteases. Cumulus expansion was evaluated based on the diameter of the COCs, the proportion of COCs participating in a floating cloud and the proportion of COCs with loss of cumulus cells. The first hypothesis of decreased EGF availability was tested by increasing the EGF concentration (20 and 50 ng/mL vs. 10 ng/mL), but was not confirmed because cumulus expansion did not improve. To verify the second hypothesis of inhibited zinc-dependent metalloproteases, the effect of tissue inhibitor of metalloproteases-3 (TIMP-3) on cumulus expansion during IVM with and without A2M was investigated. To immuno-neutralize A2M, serum was pre-incubated with A2M antibodies. Impaired cumulus expansion because of TIMP-3 could only be observed during IVM in 10% of serum with A2M antibodies. No effect of TIMP-3 was observed in medium without A2M antibodies. These results indicate that A2M and TIMP-3 share a common target, a zinc-dependent metalloprotease. Future research is directed toward the identification of the protease involved.

Progesterone receptor and prostaglandins mediate luteinizing hormone-induced changes in messenger RNAs for ADAMTS proteases in theca cells of bovine periovulatory follicles

Little is known about the ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) family of extracellular proteases in ovarian follicles of non-rodent species, particularly in theca cells. In the present study, temporal changes in the abundance of mRNA encoding four ADAMTS subtypes and hormonal regulation of mRNA encoding two subtypes were investigated in theca interna cells during the periovulatory period in cattle. Gonadotropin-releasing hormone (GnRH) was injected into animals to induce a luteinizing hormone (LH)/follicle-stimulating hormone (FSH) surge, and follicles were obtained at 0 hr post-GnRH (preovulatory) or at 6, 12, 18, or 24 hr (periovulatory). ADAMTS1, -2, -7, and -9 transcript abundance was then determined in the isolated theca interna. ADAMTS1 and -9 mRNA levels were up-regulated at 24 hr post-GnRH, whereas ADAMTS2 mRNA was higher at 12-24 hr post-GnRH and ADAMTS7 mRNA increased transiently at 12 hr post-GnRH compared to other time points. Subsequent in vitro experiments using preovulatory theca interna (0 hr post-GnRH) showed that application of LH in vitro can mimic the effects of the gonadotropin surge on mRNAs encoding ADAMTS1 and -9 and that progesterone/progesterone receptor and/or prostaglandins may regulate the levels of mRNA encoding ADAMTS1 and -9 in theca interna, downstream of the LH surge. Time- and subtype-specific changes in ADAMTS mRNA abundance in vivo, and their regulation in vitro by hormones, indicate that ADAMTS family members produced by theca cells may play important roles in follicle rupture and the accompanying tissue remodeling in cattle. Mol. Reprod. Dev. 84: 55-66, 2017. © 2016 Wiley Periodicals, Inc.

Expression of ADAMTS-1, -4, -5 and TIMP-3 in normal and multiple sclerosis CNS white matter

ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) -1, -4 and -5 proteases have been identified in the CNS at the mRNA level. These glutamyl endopeptidases, inhibited by tissue inhibitor of metalloproteinases (TIMP)-3, are key enzymes in the degradation of the aggregating chondroitin sulphate proteoglycans (CSPGs), and may therefore play a role in CNS extracellular matrix (ECM) changes in multiple sclerosis (MS). We have investigated ADAMTS and TIMP-3 expression in normal and MS CNS white matter by real-time RT-PCR, western blotting and immunohistochemistry. We report for the first time the presence of ADAMTS-1, -4 and -5 in normal and MS white matter. Levels of ADAMTS-1 and -5 mRNA were decreased in MS compared to normal tissue, with no significant change in ADAMTS-4 mRNA levels. Protein levels of ADAMTS-4 were significantly higher in MS tissue compared to normal tissue. Immunohistochemical studies demonstrated that ADAMTS-4 was associated predominantly with astrocytes with increased expression within MS lesions. TIMP-3 mRNA was significantly decreased in MS compared to controls. These studies suggest a role for ADAMTS-4 in the pathogenesis of MS. Further studies on the activity of ADAMTS-4 will enable a better understanding of its role in the turnover of the ECM of white matter in MS.

Adamts1 mediates ethanol-induced alterations in collagen and elastin via a FoxO1-sestrin3-AMPK signaling cascade in myocytes

A variety of stressors including alcohol (EtOH) are known to induce collagen production and fibrotic diseases. Matrix metalloproteinases (MMP) play an important role in regulating fibrosis, but little is known regarding the relationship between EtOH and MMPs. In addition, the signaling cascades involved in this process have not been elucidated. We have identified the MMP Adamts1 as a target of EtOH regulation. To characterize the function of Adamts1, we examined EtOH-induced alterations in collagen I and elastin protein levels in C2C12 myocytes. Incubation of myocytes with 100 mM EtOH decreased elastin and increased collagen content, respectively, and these changes were associated with increased O-GLcNAc modification of Adamts1. Conversely, silencing of Adamts1 by siRNA blocked the adverse effects of EtOH on collagen and elastin levels. Similar results were obtained after treatment with a pharmacological inhibitor of MMP. Changes in collagen were due, at least in part, to a decreased interaction of Adamts1 with its endogenous inhibitor TIMP3. The AMPK inhibitor compound C blocked the EtOH-induced stimulation of collagen and O-GLcNAc Adamts1 protein. Changes in AMPK appear linked to FoxO1, since inhibition of FoxO1 blocked the effects of EtOH on AMPK phosphorylation and O-GLcNAc levels. These FoxO-dependent modifications were associated with an upregulation of the FoxO1 transcription target sestrin 3, as well as increased binding of sestrin 3 with AMPK. Collectively, these data indicate that EtOH regulates the collagen I and elastin content in an Adamts1-dependent manner in myocytes. Furthermore, Adamts1 appears to be controlled by the FoxO1-sestrin 3-AMPK signaling cascade.

ADAMTS13 and 15 are not regulated by the full length and N-terminal domain forms of TIMP-1, -2, -3 and -4

A disintegrin and metalloproteinase with thombospondin motifs (ADAMTS) 13 and 15 are secreted zinc proteinases involved in the turnover of von Willebrand factor and cancer suppression. In the present study, ADAMTS13 and 15 were subjected to inhibition studies with the full-length and N-terminal domain forms of tissue inhibitor of metalloproteinases (TIMPs)-1 to -4. TIMPs have no ability to inhibit the ADAMTS proteinases in the full-length or N-terminal domain form. While ADAMTS13 is also not sensitive to the hydroxamate inhibitors, batimastat and ilomastat, ADAMTS15 can be effectively inhibited by batimastat (K_i^app 299 nM). In conclusion, the present results indicate that TIMPs are not the regulators of these two ADAMTS proteinases.