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The ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin motifs) enzymes are secreted, multi-domain matrix-associated zinc metalloendopeptidases that have diverse roles in tissue morphogenesis and patho-physiological remodeling, in inflammation and in vascular biology. The human family includes 19 members that can be sub-grouped on the basis of their known substrates, namely the aggrecanases or proteoglycanases (ADAMTS1, 4, 5, 8, 9, 15 and 20), the procollagen N-propeptidases (ADAMTS2, 3 and 14), the cartilage oligomeric matrix protein-cleaving enzymes (ADAMTS7 and 12), the von-Willebrand Factor proteinase (ADAMTS13) and a group of orphan enzymes (ADAMTS6, 10, 16, 17, 18 and 19). Control of the structure and function of the extracellular matrix (ECM) is a central theme of the biology of the ADAMTS, as exemplified by the actions of the procollagen-N-propeptidases in collagen fibril assembly and of the aggrecanases in the cleavage or modification of ECM proteoglycans. Defects in certain family members give rise to inherited genetic disorders, while the aberrant expression or function of others is associated with arthritis, cancer and cardiovascular disease. In particular, ADAMTS4 and 5 have emerged as therapeutic targets in arthritis. Multiple ADAMTSs from different sub-groupings exert either positive or negative effects on tumorigenesis and metastasis, with both metalloproteinase-dependent and -independent actions known to occur. The basic ADAMTS structure comprises a metalloproteinase catalytic domain and a carboxy-terminal ancillary domain, the latter determining substrate specificity and the localization of the protease and its interaction partners; ancillary domains probably also have independent biological functions. Focusing primarily on the aggrecanases and proteoglycanases, this review provides a perspective on the evolution of the ADAMTS family, their links with developmental and disease mechanisms, and key questions for the future.

Viral myocarditis, an inflammatory disease of the heart, causes significant morbidity and mortality. Type I interferon (IFN)-mediated antiviral responses protect against myocarditis, but the mechanisms are poorly understood. We previously identified A Disintegrin And Metalloproteinase domain 9 (ADAM9) as an important factor in viral pathogenesis. ADAM9 is implicated in a range of human diseases, including inflammatory diseases; however, its role in viral infection is unknown. Here, we demonstrate that mice lacking ADAM9 are more susceptible to encephalomyocarditis virus (EMCV)-induced death and fail to mount a characteristic type I IFN response. This defect in type I IFN induction is specific to positive-sense, single-stranded RNA (+ ssRNA) viruses and involves melanoma differentiation-associated protein 5 (MDA5)—a key receptor for +ssRNA viruses. Mechanistically, ADAM9 binds to MDA5 and promotes its oligomerization and thereby downstream mitochondrial antiviral-signaling protein (MAVS) activation in response to EMCV RNA stimulation. Our findings identify a role for ADAM9 in the innate antiviral response, specifically MDA5-mediated IFN production, which protects against virus-induced cardiac damage, and provide a potential therapeutic target for treatment of viral myocarditis. Mice lacking A Disintegrin and Metalloproteinase 9 (ADAM9) do not mount Type 1 interferon responses against encephalomyocarditis infection. Here, Bazzone et al show that ADAM9 regulates innate immune responses via by MDA5.

ADAM9 (A disintegrin and a metalloprotease 9) is a membrane-anchored protein that participates in a variety of physiological functions, primarily through the disintegrin domain for adhesion and the metalloprotease domain for ectodomain shedding of a wide variety of cell surface proteins. ADAM9 influences the developmental process, inflammation, and degenerative diseases. Recently, increasing evidence has shown that ADAM9 plays an important role in tumor biology. Overexpression of ADAM9 has been found in several cancer types and is correlated with tumor aggressiveness and poor prognosis. In addition, through either proteolytic or non-proteolytic pathways, ADAM9 promotes tumor progression, therapeutic resistance, and metastasis of cancers. Therefore, comprehensively understanding the mechanism of ADAM9 is crucial for the development of therapeutic anti-cancer strategies. In this review, we summarize the current understanding of ADAM9 in biological function, pathophysiological diseases, and various cancers. Recent advances in therapeutic strategies using ADAM9-related pathways are presented as well.

A disintegrin and metalloproteinase 10 (ADAM10), a disintegrin and metalloproteinase that resides in the postsynaptic densities (PSDs) of excitatory synapses, has previously been shown to limit β-amyloid peptide (Aβ) formation in Alzheimer's disease (AD). ADAM10 also plays a critical role in regulating functional membrane proteins at the synapse. Using human hippocampal homogenates, we found that ADAM10 removal from the plasma membrane was mediated by clathrin-dependent endocytosis. Additionally, we identified the clathrin adaptor AP2 as an interacting partner of a previously uncharacterized atypical binding motif in the ADAM10 C-terminal domain. This domain was required for ADAM10 endocytosis and modulation of its plasma membrane levels. We found that the ADAM10/AP2 association was increased in the hippocampi of AD patients compared with healthy controls. Long-term potentiation (LTP) in hippocampal neuronal cultures induced ADAM10 endocytosis through AP2 association and decreased surface ADAM10 levels and activity. Conversely, long-term depression (LTD) promoted ADAM10 synaptic membrane insertion and stimulated its activity. ADAM10 interaction with the synapse-associated protein-97 (SAP97) was necessary for LTD-induced ADAM10 trafficking and required for LTD maintenance and LTD-induced changes in spine morphogenesis. These data identify and characterize a mechanism controlling ADAM10 localization and activity at excitatory synapses that is relevant to AD pathogenesis.

Organ fibrosis often leads to end-stage organ failure, but the origin of key profibrotic cell types is still unclear. Lucie Peduto and her colleagues have used genetic lineage tracing and pharmacological ablation techniques to show that ADAM12 + perivascular cells are a key source of profibrotic cells in acute skin and muscle injury in the mouse. They also show that knockdown of ADAM12 expression is beneficial, suggesting a possible therapeutic target for the treatment of fibrosis. Profibrotic cells that develop upon injury generate permanent scar tissue and impair organ recovery, though their origin and fate are unclear. Here we show that transient expression of ADAM12 (a disintegrin and metalloprotease 12) identifies a distinct proinflammatory subset of platelet-derived growth factor receptor-α–positive stromal cells that are activated upon acute injury in the muscle and dermis. By inducible genetic fate mapping, we demonstrate in vivo that injury-induced ADAM12 + cells are specific progenitors of a major fraction of collagen-overproducing cells generated during scarring, which are progressively eliminated during healing. Genetic ablation of ADAM12 + cells, or knockdown of ADAM12, is sufficient to limit generation of profibrotic cells and interstitial collagen accumulation. ADAM12 + cells induced upon injury are developmentally distinct from muscle and skin lineage cells and are derived from fetal ADAM12 + cells programmed during vascular wall development. Thus, our data identify injury-activated profibrotic progenitors residing in the perivascular space that can be targeted through ADAM12 to limit tissue scarring.

The metalloprotease ADAM10 mediates the shedding of the ectodomain of various cell membrane proteins, including APP, the precursor of the amyloid peptide Aβ, and Notch receptors following ligand binding. ADAM10 associates with the members of an evolutionary conserved subgroup of tetraspanins, referred to as TspanC8, which regulate its exit from the endoplasmic reticulum. Here we show that 4 of these TspanC8 (Tspan5, Tspan14, Tspan15 and Tspan33) which positively regulate ADAM10 surface expression levels differentially impact ADAM10-dependent Notch activation and the cleavage of several ADAM10 substrates, including APP, N-cadherin and CD44. Sucrose gradient fractionation, single molecule tracking and quantitative mass-spectrometry analysis of the repertoire of molecules co-immunoprecipitated with Tspan5, Tspan15 and ADAM10 show that these two tetraspanins differentially regulate ADAM10 membrane compartmentalization. These data represent a unique example where several tetraspanins differentially regulate the function of a common partner protein through a distinct membrane compartmentalization.

Cancer-associated fibroblasts (CAFs) drive tumour progression, but the emergence of this cell state is poorly understood. A broad spectrum of metalloproteinases, controlled by the Timp gene family, influence the tumour microenvironment in human cancers. Here, we generate quadruple TIMP knockout (TIMPless) fibroblasts to unleash metalloproteinase activity within the tumour-stromal compartment and show that complete Timp loss is sufficient for the acquisition of hallmark CAF functions. Exosomes produced by TIMPless fibroblasts induce cancer cell motility and cancer stem cell markers. The proteome of these exosomes is enriched in extracellular matrix proteins and the metalloproteinase ADAM10. Exosomal ADAM10 increases aldehyde dehydrogenase expression in breast cancer cells through Notch receptor activation and enhances motility through the GTPase RhoA. Moreover, ADAM10 knockdown in TIMPless fibroblasts abrogates their CAF function. Importantly, human CAFs secrete ADAM10-rich exosomes that promote cell motility and activate RhoA and Notch signalling in cancer cells. Thus, Timps suppress cancer stroma where activated-fibroblast-secreted exosomes impact tumour progression. Khokha and colleagues report that loss of the Timp family of metalloproteinases from stromal fibroblasts promotes a cancer-associated fibroblast phenotype and production of exosomes that stimulate cancer cell motility.

No biomarker can effectively screen for early gastric cancer (EGC). Players in the A disintegrin and metalloproteinase (ADAM)-natural killer group 2 member D (NKG2D) receptor axis may have a role for that. As a proof-of-concept pilot study, the expression of ADAM8, ADAM9, ADAM10, ADAM12, ADAM17, and major histocompatibility complex (MHC) class I chain-related sequence A (MICA), a ligand for NKG2D, in gastric cancer was investigated in silico using The Cancer Genome Atlas (TCGA) database. Subsequently, the mRNA and protein expression levels of these markers except ADAM8 were tested in blood samples from patients with EGC and healthy controls. In the TCGA data analyses, EGC tissues ( n  = 57) expressed significantly higher mRNA levels of ADAM8 , ADAM9 , ADAM10 , ADAM12 , and ADAM17 than normal tissues ( n  = 35) ( p  < 0.005). In human blood sample analyses, ADAM12 (p =  0.0007), ADAM 17 mRNA ( p  < 0.0001) and ADAM10 ( p  < 0.001 7 ) protein were significantly elevated in patients with EGC ( n  = 27 for mRNA and n  = 25 for protein) compared to the controls ( n  = 30 for mRNA and n  = 26 for protein). Areas under the curves calculated by receiver-operating characteristic analysis for ADAM12 , ADAM17 mRNA and ADAM10 protein were 0.7568 (95% confidence interval [CI]: 0.6334 to 0.8802), 0.8062 (95% CI: 0.6889 to 0.9234; p  < 0.0001), and 0.8108 (95% CI: 0.6895 to 0.9320; p  = 0.0001), respectively. Thus, ADAM12 , ADAM17 mRNA and ADAM10 protein levels in peripheral blood could hold potential as biomarkers for screening EGC, and further investigations are required.

Metalloproteinases cleave transmembrane proteins that play critical roles in inflammation and cancers. Metalloproteinases include a disintegrin and metalloprotease (ADAM), which we previously examined using a fluorescence assay system, and described their association with resistance to systemic therapy in cancer patients. There are also many reports on the relation between ADAM expression and the prognosis of patients with gastroenterological chronic inflammatory diseases and cancers. Inhibiting their immunomodulating activity in chronic inflammation restores innate immunity and potentially prevents the development of various cancers. Among the numerous critical immune system-related molecules, we focus on major histocompatibility complex class I polypeptide-related sequence A (MICA), MICB, intracellular adhesion molecule (ICAM)-1, TNF-α, IL-6 receptor (IL-6R), and Notch. This review summarizes our current understanding of the role of ADAMs in gastroenterological diseases with regard to the immune system. Several Food and Drug Administration (FDA)-approved inhibitors of ADAMs have been identified, and potential therapies for targeting ADAMs in the treatment of chronic inflammatory diseases and cancers are discussed. Some ongoing clinical trials for cancers targeting ADAMs are also introduced.

Osteoarthritis (OA) is a joint disease in which cartilage degradation is the hallmark pathological change. In this study, we investigated the anti-osteoarthritic effects of DHEA in rabbit chondrocytes. Polymerase chain reaction was performed to evaluate the expression of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4, ADAMTS-5, aggrecan and collagen type 2. In addition, ERK1/2 signaling pathway components were analyzed by Western blotting. In IL-1β-induced chondrocytes, the phosphorylation of ERK1/2 was enhanced, and the downstream catabolic genes, including ADAMTS-4 and ADAMTS-5, were upregulated, while the anabolic genes aggrecan and collagen type 2 were downregulated. DHEA administration restored the IL-1β-induced imbalance in anabolic and catabolic gene expression. In addition, the phosphorylation of ERK1/2 was suppressed by DHEA. Then, PD98059 was used to block the ERK1/2 signaling pathway. The protective effect of DHEA was significantly increased when ERK1/2 signaling was inactivated. DHEA may exert its protective effect by suppressing ADAMTS in an ERK1/2-dependent manner in rabbit chondrocytes.