A Disintegrin And Metalloprotease Proteins Research Articles

The evolution of ADAM gene family in eukaryotes

The ADAM (A Disintegrin And Metalloprotease) gene family encodes proteins with adhesion and proteolytic functions. ADAM proteins are associated with diseases like cancers. Twenty ADAM genes have been identified in humans. However, little is known about the evolution of the family. We analyzed the repertoire of ADAM genes in a vast number of eukaryotic genomes to clarify the main gene copy number expansions. For the first time, we provide compelling evidence that early-branching green algae (Mamiellophyceae) have ADAM genes, suggesting that they originated in the last common ancestor of eukaryotes, before the split of plants, fungi and animals. The ADAM family expanded in early metazoans, with the most significative gene expansion happening during the first steps of vertebrate evolution. We concluded that most of mammal ADAM diversity can be explained by gene duplications in early bone fish. Our data suggest that ADAM genes were lost early in green plant evolution.

Changes in gene expression in human skeletal stem cells transduced with constitutively active Gsα correlates with hallmark histopathological changes seen in fibrous dysplastic bone.

Fibrous dysplasia (FD) of bone is a complex disease of the skeleton caused by dominant activating mutations of the GNAS locus encoding for the α subunit of the G protein-coupled receptor complex (Gsα). The mutation involves a substitution of arginine at position 201 by histidine or cysteine (GsαR201H or R201C), which leads to overproduction of cAMP. Several signaling pathways are implicated downstream of excess cAMP in the manifestation of disease. However, the pathogenesis of FD remains largely unknown. The overall FD phenotype can be attributed to alterations of skeletal stem/progenitor cells which normally develop into osteogenic or adipogenic cells (in cis), and are also known to provide support to angiogenesis, hematopoiesis, and osteoclastogenesis (in trans). In order to dissect the molecular pathways rooted in skeletal stem/progenitor cells by FD mutations, we engineered human skeletal stem/progenitor cells with the GsαR201C mutation and performed transcriptomic analysis. Our data suggest that this FD mutation profoundly alters the properties of skeletal stem/progenitor cells by pushing them towards formation of disorganized bone with a concomitant alteration of adipogenic differentiation. In addition, the mutation creates an altered in trans environment that induces neovascularization, cytokine/chemokine changes and osteoclastogenesis. In silico comparison of our data with the signature of FD craniofacial samples highlighted common traits, such as the upregulation of ADAM (A Disintegrin and Metalloprotease) proteins and other matrix-related factors, and of PDE7B (Phosphodiesterase 7B), which can be considered as a buffering process, activated to compensate for excess cAMP. We also observed high levels of CEBPs (CCAAT-Enhancer Binding Proteins) in both data sets, factors related to browning of white fat. This is the first analysis of the reaction of human skeletal stem/progenitor cells to the introduction of the FD mutation and we believe it provides a useful background for further studies on the molecular basis of the disease and for the identification of novel potential therapeutic targets.

ADAM and ADAMTS Proteases in Hepatic Disorders

Proteolysis is an irreversible post-translational modification that regulates protein function and signal transduction. This includes remodelling of the extracellular matrix, release of membrane-bound cytokines and receptor ectodomains, as well as the initiation of intracellular signalling cues. Members of the adamalysin protease subfamily, in particular the ADAM (a disintegrin and metalloprotease) and ADAMTS (the ADAM containing thrombospondin motif) families, are involved in these processes. This review presents an overview of how ADAM and ADAMTS proteins are involved in liver physiology and pathophysiology.

Multiple non-catalytic ADAMs are novel integrin α4 ligands.

The ADAM (a disintegrin and metalloprotease) protein family uniquely exhibits both catalytic and adhesive properties. In the well-defined process of ectodomain shedding, ADAMs transform latent, cell-bound substrates into soluble, biologically active derivatives to regulate a spectrum of normal and pathological processes. In contrast, the integrin ligand properties of ADAMs are not fully understood. Emerging models posit that ADAM-integrin interactions regulate shedding activity by localizing or sequestering the ADAM sheddase. Interestingly, 8 of the 21 human ADAMs are predicted to be catalytically inactive. Unlike their catalytically active counterparts, integrin recognition of these "dead" enzymes has not been largely reported. The present study delineates the integrin ligand properties of a group of non-catalytic ADAMs. Here we report that human ADAM11, ADAM23, and ADAM29 selectively support integrin α4-dependent cell adhesion. This is the first demonstration that the disintegrin-like domains of multiple catalytically inactive ADAMs are ligands for a select subset of integrin receptors that also recognize catalytically active ADAMs.

Metalloproteinases ADAM12 and MMP-14 are associated with cavernous sinus invasion in pituitary adenomas.

Invasion of tumor cells critically depends on cell-cell or cell-extracellular matrix interactions. Enzymes capable of modulating these interactions belong to the proteinase families of ADAM (a disintegrin and metalloprotease) and MMP (matrix metalloprotease) proteins. Our objective is to examine their expression levels and evaluate the relationship between expression levels and cavernous sinus invasion in pituitary adenomas. Tissue samples from 35 patients with pituitary adenomas were analyzed. Quantitative real-time polymerase chain reaction (qPCR) was employed to assess mRNA expression levels for ADAM and MMP genes. Protein levels were examined using immunohistochemistry and Western Blot. Correlation analyses between expression levels and clinical parameters were performed. By silencing ADAM12 and MMP-14 with siRNA in a mouse pituitary adenoma cell line (TtT/GF), their cellular effects were investigated. In our study, nine women and 26 men were included, with a mean age of 53.1 years (range 15-84 years) at the time of surgery. There were 19 cases with cavernous sinus invasion. The proteins ADAM12 and MMP-14 were significantly up-regulated in invasive adenomas compared to noninvasive adenomas. Both human isoforms of ADAM12 (ADAM12L and ADAM12s) were involved in tumor invasion; moreover, ADAM12L was found to correlate positively with Ki-67 proliferation index in pituitary adenomas. In TtT/GF pituitary adenoma cells, silencing of ADAM12 and MMP-14 significantly inhibited cell invasion and migration, respectively, whereas only silencing of ADAM12 suppressed cell proliferation. We conclude that ADAM12 and MMP-14 are associated with cavernous sinus invasion in pituitary adenomas, which qualifies these proteins in diagnosis and therapy.

Retinoids induce integrin-independent lymphocyte adhesion through RAR-α nuclear receptor activity

Oxidative metabolites of vitamin A, in particular all-trans-retinoic acid (atRA), have emerged as key factors in immunity by specifying the localization of immune cells to the gut. Although it is appreciated that isomers of retinoic acid activate the retinoic acid receptor (RAR) and retinoid X receptor (RXR) family of nuclear receptors to elicit cellular changes, the molecular details of retinoic acid action remain poorly defined in immune processes. Here we employ a battery of agonists and antagonists to delineate the specific nuclear receptors utilized by retinoids to evoke lymphocyte cell adhesion to ADAM (adisintegrin and metalloprotease) protein family members. We report that RAR agonism is sufficient to promote immune cell adhesion in both immortal and primary immune cells. Interestingly, adhesion occurs independent of integrin function, and mutant studies demonstrate that atRA-induced adhesion to ADAM members required a distinct binding interface(s) as compared to integrin recognition. Anti-inflammatory corticosteroids as well as 1,25-(OH)2D3, a vitamin D metabolite that prompts immune cell trafficking to the skin, potently inhibited the observed adhesion. Finally, our data establish that induced adhesion was specifically attributable to the RAR-α receptor isotype. The current study provides novel molecular resolution as to which nuclear receptors transduce retinoid exposure into immune cell adhesion.

Quantitative and dynamic expression profile of premature and active forms of the regional ADAM proteins during chicken brain development

The ADAM (A Disintegrin and Metalloprotease) family of transmembrane proteins plays important roles in embryogenesis and tissue formation based on their multiple functional domains. In the present study, for the first time, the expression patterns of the premature and the active forms of six members of the ADAM proteins — ADAM9, ADAM10, ADAM12, ADAM17, ADAM22 and ADAM23 — in distinct parts of the developing chicken brain were investigated by quantitative Western blot analysis from embryonic incubation day (E) 10 to E20. The results show that the premature and the active forms of various ADAM proteins are spatiotemporally regulated in different parts of the brain during development, suggesting that the ADAMs play a very important role during embryonic development.

The disintegrin and metalloprotease Meltrin from Drosophila forms oligomers via its protein binding domain and is regulated by the homeobox protein VND during embryonic development

A Disintegrin And Metalloprotease (ADAM) proteins belong to the metzincin superfamily of metalloproteases that are known to play important roles in several physiological and developmental processes including myoblast fusion, tumor necrosis factor-α release or fertilization. They are characterized by a typical domain structure with a proteolytically active domain and the protein binding domains both facing the extracellular space. Regulatory mechanisms are largely unknown. Here we report on the potential of the Drosophila ADAM Meltrin to form oligomers via its substrate binding domain. Significantly, oligomerization occurs apparently in a redox-dependent manner. Further analysis revealed that the ACR domain is responsible for aggregation while the disintegrin-like and EGF-like domains are not capable of oligomer formation. Stage dependent transcript analysis revealed a constant expression of three different splice variants, two of which were characterized by sequencing. Like many other ADAM proteins, Meltrin shows a highly restricted expression pattern during embryogenesis with at least two of the respective transcripts being present in a subpopulation of neuronal cells in the embryonic central nervous system. Finally, we report on the identification of the first regulator of meltrin: the homeobox protein ventral nervous system defective specifically excludes Meltrin expression from the embryonic ventral neuroectoderm.

Characterization of a Novel ADAM Protease Expressed byPneumocystis carinii

Pneumocystis species are opportunistic fungal pathogens that cause severe pneumonia in immunocompromised hosts. Recent evidence has suggested that unidentified proteases are involved in Pneumocystis life cycle regulation. Proteolytically active ADAM (named for "a disintegrin and metalloprotease") family molecules have been identified in some fungal organisms, such as Aspergillus fumigatus and Schizosaccharomyces pombe, and some have been shown to participate in life cycle regulation. Accordingly, we sought to characterize ADAM-like molecules in the fungal opportunistic pathogen, Pneumocystis carinii (PcADAM). After an in silico search of the P. carinii genomic sequencing project identified a 329-bp partial sequence with homology to known ADAM proteins, the full-length PcADAM sequence was obtained by PCR extension cloning, yielding a final coding sequence of 1,650 bp. Sequence analysis detected the presence of a typical ADAM catalytic active site (HEXXHXXGXXHD). Expression of PcADAM over the Pneumocystis life cycle was analyzed by Northern blot. Southern and contour-clamped homogenous electronic field blot analysis demonstrated its presence in the P. carinii genome. Expression of PcADAM was observed to be increased in Pneumocystis cysts compared to trophic forms. The full-length gene was subsequently cloned and heterologously expressed in Saccharomyces cerevisiae. Purified PcADAMp protein was proteolytically active in casein zymography, requiring divalent zinc. Furthermore, native PcADAMp extracted directly from freshly isolated Pneumocystis organisms also exhibited protease activity. This is the first report of protease activity attributable to a specific, characterized protein in the clinically important opportunistic fungal pathogen Pneumocystis.

ADAM Proteins- Therapeutic Potential in Cancer

The A Disintegrin And Metalloprotease (ADAM) proteins belong to the metzincin-superfamily of Zn-dependent metalloproteinases that shed the extracellular domains of membrane-bound growth factors, cytokines and their receptors. The latter play a central role in cell signaling and contribute a potential target in cancer therapy. Of particular interest are the ErBB/HER family of growth factor receptors associated with elevated intrinsic tyrosine kinase activity. Overexpression of ADAMs and cell signaling components have also been implicated in the development and progression of a variety of tumor types. Emerging evidence has suggested that the ADAM proteins are involved in tumour cell proliferation, in angiogenesis as well as metastasis. Therefore, strategies targeting ADAMs may constitute an important target for the design of cancer drugs. The review will focus on current understanding of the role of ADAM in the physiological and pathological functions associated with cancer. It is the intention of the review to provide insights which may assist in the development of ADAM-based approaches for the treatment of human cancers.

ADAM-15/Metargidin Mediates Homotypic Aggregation of Human T Lymphocytes and Heterotypic Interactions of T Lymphocytes with Intestinal Epithelial Cells

Intestinal epithelial cells (IEC) play an immunoregulatory role in the intestine. This role involves cell-cell interactions with intraepithelial lymphocytes that may also play a role in some enteropathies. The discovery of the RGD motif-containing Protein ADAM-15 (a disintegrin and metalloprotease-15) raises the question of its involvement in these cell-cell interactions. Cell adhesion assays were performed using the Jurkat E6.1 T cell line as a model of T lymphocytes and Caco2-BBE monolayers as a model of intestinal epithelia. Our results show that an anti-ADAM-15 ectodomain antibody inhibited the attachment of Jurkat cells on Caco2-BBE monolayers. Overexpression of ADAM-15 in Caco2-BBE cells enhanced Jurkat cell binding, and overexpression of ADAM-15 in Jurkat cells enhanced their aggregation. Mutagenesis experiments showed that both the mutation of ADAM-15 RGD domain or the deletion of its cytoplasmic tail decreased these cell-cell interactions. Moreover, wound-healing experiments showed that epithelial ADAM-15-mediated Jurkat cell adhesion to Caco2-BBE cells enhances the mechanisms of wound repair. We also found that ADAM-15-mediated aggregation of Jurkat cells increases the expression of tumor necrosis factor-alpha mRNA. These results demonstrate the following: 1) ADAM-15 is involved in heterotypic adhesion of intraepithelial lymphocytes to IEC as well as in homotypic aggregation of T cells; 2) both the RGD motif and the cytoplasmic tail of ADAM-15 are involved for these cell-cell interactions; and 3) ADAM-15-mediated cell-cell interactions are involved in mechanisms of epithelial restitution and production of pro-inflammatory mediators. Altogether these findings point to ADAM-15 as a possible therapeutic target for prevention of inappropriate T cell activation involved in some pathologies.

ADAM23 Plays Multiple Roles in Neuronal Differentiation of P19 Embryonal Carcinoma cells

ADAM23, belonging to ADAM (A Disintegrin And Metalloprotease) protein family, is mainly expressed in brain. P19 cells could differentiate into neuroectodermal cell lineage after cell aggregates have been induced by retinoic acid (RA). In this report, we show that the post-transcriptional and post-translational processes of ADAM23 are regulated during the differentiation of P19 cells. In P19-derived neurons, ADAM23 is polarized distributed in the proximal part. To explore the possible roles of ADAM23 during P19 cell neuronal differentiation, ADAM23-RNAi P19 cell lines were established. These transfected cells could differentiate into neurofilament-expression neurons in the absence of RA, whereas wild-type P19 cell can not. These results suggest ADAM23 may play roles in both early and later stage of neuronal differentiation.

Structure-Activity Relationship Studies on ADAM Protein-Integrin Interactions

The ADAM (a disintegrin and metalloprotease) family of proteins possess multi-domain structures composed of a signal peptide, a prodomain, a metalloprotease domain, a disintegrin-like domain, a cysteine rich domain, an epidermal growth factor-like domain, a transmembrane domain and cytoplasmic tail. The disintegrin-like domain shares sequence similarity with the soluble venom disintegrins, a family of proteins which are potent inhibitors of integrin-mediated platelet aggregation and cell adhesion. Several ADAMs have been reported to interact with integrins, and the disintegrin-like domain may be crucial part in this respect. A description of structure-activity relationship of ADAM proteins interacting with integrin is outlined in this review. The review highlights recent reports on potential integrin family for ADAMs and how ADAMs selectively modulate interaction for integrin mediated cell function. Lastly, it describes progress in understanding the structural features and functional roles of the ADAMs in normal and pathological conditions and how this insight may assist the development of new therapeutic approaches.

5-HT2A Receptor Induces ERK Phosphorylation and Proliferation through ADAM-17 Tumor Necrosis Factor-α-converting Enzyme (TACE) Activation and Heparin-bound Epidermal Growth Factor-like Growth Factor (HB-EGF) Shedding in Mesangial Cells

In this study, we present multiple lines of evidence to support a critical role for heparin-bound EGF (epidermal growth factor)-like growth factor (HB-EGF) and tumor necrosis factor-alpha-converting enzyme (TACE) (ADAM17) in the transactivation of EGF receptor (EGFR), ERK phosphorylation, and cellular proliferation induced by the 5-HT(2A) receptor in renal mesangial cells. 5-hydroxy-tryptamine (5-HT) resulted in rapid activation of TACE, HB-EGF shedding, EGFR activation, ERK phosphorylation, and longer term increases in DNA content in mesangial cells. ERK phosphorylation was attenuated by 1) neutralizing EGFR antibodies and the EGFR kinase inhibitor, AG1478, 2) neutralizing HB-EGF, but not amphiregulin, antibodies, heparin, or CM197, and 3) pharmacological inhibitors of matrix-degrading metalloproteinases or TACE small interfering RNA. Exogenously administered HB-EGF stimulated ERK phosphorylation. Additionally, TACE was co-immunoprecipitated with HB-EGF. Small interfering RNA against TACE also blocked 5-HT-induced increases in ERK phosphorylation, HB-EGF shedding, and DNA content. In aggregate, this work supports a pathway map that can be depicted as follows: 5-HT --> 5-HT(2A) receptor --> TACE --> HB-EGF shedding --> EGFR --> ERK --> increased DNA content. To our knowledge, this is the first time that TACE has been implicated in 5-HT-induced EGFR transactivation or in proliferation induced by a G protein-coupled receptor in native cells in culture.

A disintegrin and metalloprotease 21 (ADAM21) is associated with neurogenesis and axonal growth in developing and adult rodent CNS

We have reported that alpha6beta1 integrin regulates the directed migration of neuroblasts from the adult rodent subventricular zone (SVZ) through the rostral migratory stream (RMS). ADAM (a disintegrin and metalloprotease) proteins bind integrins. Here, we show that ADAM21, but not ADAM2, -3, -9, -10, -12, -15, or -17, is expressed in adult rats and mice by ependyma and SVZ cells with long basal processes, and in radial glia at early postnatal times. ADAM21-positive processes projected into the RMS, contacted blood vessels, and were present within the RMS intermingled with neuroblasts up to where neuroblasts start their radial migration and differentiation in the olfactory bulb. Tissue inhibitors of metalloproteases (TIMPs) 1, 2, and 3 are present in the ependymal layer but not in the SVZ and RMS. Thus, ADAM21 could regulate neurogenesis and guide neuroblast migration through cleavage-dependent activation of proteins and integrin binding. ADAM21 is also present in growing axonal tracts during postnatal development and in growing primary olfactory axons in adults. In the olfactory nerve layer, ADAM21 often, but not always, colocalizes with OMP, a marker of mature olfactory neurons, but is not colocalized with the immature marker betaIII-tubulin. This suggests that ADAM21 is involved in the final axonal outgrowth phase and/or synapse formation. TIMP3 is present in periglomerular neurons, where it could restrict ADAM21-mediated axonal growth to the glomeruli. ADAM21's unique disintegrin and metalloprotease sequences and its restricted expression suggest that it might be a good target for influencing neurogenesis and neuronal plasticity.

ADAM-Integrin Interactions: Potential Integrin Regulated Ectodomain Shedding Activity

ADAMs (a disintegrin and metalloprotease) are a family of cell surface proteins related to the Class III snake venom metalloproteases (SVMP). ADAMs are members of the Metazincin family which includes the matrix matalloproteases and the ADAMTS proteins. Unlike their snake venom relatives, ADAMs are expressed as transmembrane cell surface proteins. The domain structure of ADAMs suggests that these proteins posses both proteolytic and adhesive functions. Several members of the ADAM protein family have been shown to be involved in ectodomain shedding of many important cell surface proteins resulting in the release of biologically active soluble factors. The carboxyl-terminal domains, especially the disintegrin-like domain of ADAMs, have been demonstrated to support cell adhesion. The disintegrin-like domains of many ADAMs are capable of acting as integrin ligands. Integrins known to interact with ADAM disintegrin-like domains include alpha4beta1, alpha4beta7, alpha5beta1, alpha6beta1, alpha9beta1, alphavbeta3, and alphavbeta5. This integrin mediated interaction of the disintegrin-like domains with the cell surface suggests that ADAMs may function as cellular counter receptors. In this review we discuss the individual functions ascribed to members of the ADAM family especially those related to integrin interactions and the potential for integrin mediated regulation of ectodomain shedding.

ADAMs: key components in EGFR signalling and development

ADAM (a disintegrin and metalloprotease) proteins are membrane-anchored metalloproteases that process and shed the ectodomains of membrane-anchored growth factors, cytokines and receptors. ADAMs also have essential roles in fertilization, angiogenesis, neurogenesis, heart development and cancer. Research on ADAMs and their role in protein ectodomain shedding is emerging as a fertile ground for gathering new insights into the functional regulation of membrane proteins.

A Fibulin-1 Homolog Interacts with an ADAM Protease that Controls Cell Migration in C. elegans

ADAM (a disintegrin and metalloprotease) family proteins play important roles in animal development and pathogenesis. In C. elegans, a secreted ADAM protein, MIG-17, acts from outside the gonad to control the migration of gonadal distal tip cells (DTCs) that promote gonad morphogenesis. Here, we report that dominant mutations in the fbl-1 gene encoding fibulin-1 spliced isoforms, which are calcium binding extracellular matrix proteins, bypass the requirement for MIG-17 activity in directing DTC migration. Specific amino acid substitutions in the third EGF-like motif of one of the two isoforms, FBL-1C, which corresponds to mammalian fibulin-1C, suppress mig-17 mutations. FBL-1C is synthesized in the gut cells and localizes strongly to the gonadal basement membrane in a MIG-17-dependent manner. Localization of mutant FBL-1C is weaker than that of the wild-type protein and is insensitive to MIG-17 activity, suggesting that it gains a novel function that compensates for its reduced molecular density. We propose that proteolysis by MIG-17 recruits FBL-1C to the gonadal basement membrane, where it is required for the guidance of DTCs, and that mutant FBL-1C acts in a manner that mimics the downstream events of MIG-17-mediated proteolysis.

Novel metalloprotease-disintegrin, meltrin epsilon (ADAM35), expressed in epithelial tissues during chick embryogenesis.

Members of the ADAM (a disintegrin and metalloprotease) family are involved in fertilization, morphogenesis, and pathogenesis. Their metalloprotease domains mediate limited proteolysis, including ectodomain shedding of membrane-anchored growth factors and intercellular-signaling proteins, and their disintegrin domains play regulatory roles in cell adhesion and migration. In screening for cDNAs encoding chicken ADAM proteins expressed during muscle development, we identified Meltrin epsilon as a novel member of this family. To elucidate its functions, we investigated its expression during development by using antibodies raised against its protease domain. In the somites, Meltrin epsilon protein was specifically expressed in the myotomal cells, which delaminate from the dermomyotome to form epithelial sheets. It was also found in the surface ectoderm, lens placodes, otic vesicles, and the gut epithelia. Basolateral localization of Meltrin epsilon in these epithelial cells suggests its unique roles in the organization of the epithelial tissues and development of the sensory organs and the gut.

UNC-71, a disintegrin and metalloprotease (ADAM) protein, regulates motor axon guidance and sex myoblast migration in C. elegans.

The migration of cells and growth cones is a process that is guided by extracellular cues and requires the controlled remodeling of the extracellular matrix along the migratory path. The ADAM proteins are important regulators of cellular adhesion and recognition because they can combine regulated proteolysis with modulation of cell adhesion. We report that the C. elegans gene unc-71 encodes a unique ADAM with an inactive metalloprotease domain. Loss-of-function mutations in unc-71 cause distinct defects in motor axon guidance and sex myoblast migration. Many unc-71 mutations affect the disintegrin and the cysteine-rich domains, supporting a major function of unc-71 in cell adhesion. UNC-71 appears to be expressed in a selected set of cells. Genetic mosaic analysis and tissue-specific expression studies indicate that unc-71 acts in a cell non-autonomous manner for both motor axon guidance and sex myoblast migration. Finally, double mutant analysis of unc-71 with other axon guidance signaling molecules suggests that UNC-71 probably functions in a combinatorial manner with integrins and UNC-6/netrin to provide distinct axon guidance cues at specific choice points for motoneurons.