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Background: Heart failure (HF) is a highly heterogeneous disorder characterized by the interactions of multiple genetic and environmental factors as well as the interaction of different cell types in the heart. Although reductionistic approaches have successfully identified many genes involved in HF, heritability studies suggest that many genes have resisted discovery through these approaches. By utilizing cell-type-specific gene expression paired with transcriptomic data from a large cohort of mice, we sought to identify important drivers of HF using a systems genetics approach. Methods and Results: Mice from 93 unique inbred lines of the Hybrid Mouse Diversity Panel were given 30 ug/g/day of isoproterenol for three weeks via osmotic minipump to induce heart failure. Transcriptomes were generated from these mice and the weighted Maximal Information Component Analysis (wMICA) algorithm was applied to generate transcriptomic gene networks. Cardiomyocytes and Fibroblasts were isolated from both control and isoproterenol-treated adult C57BL/6J hearts using a Langendorff apparatus (n=3 per sex/treatment) and transcriptomes were generated. Significantly differentially expressed genes were identified using DESEQ2 and used to query the wMICA-derived network, identifying the gene Adamts2 as a potential regulator of cardiac hypertrophy. Follow-up in vitro and in vivo work has demonstrated that Adamts2 knockdown significantly blunts the hypertrophic effect of isoproterenol on cardiomyocytes while simultaneously reducing fibroblast proliferation and increasing apoptosis as measured by TUNEL staining. Careful examination of the gene network reveals evidence of paracrine signaling between cardiomyocytes and fibroblasts and suggests a key trans-cell-type role of Adamts2 in the regulation of HF after catecholamine stimulation. Conclusion: Co-expression network algorithms combined with cell-type-specific transcriptomics identified Adamts2 as a driver of HF. Adamts2 plays an important role via paracrine signaling in the proliferative response of fibroblasts and the hypertrophic response of cardiomyocytes to catecholamines. Further mechanistic analysis of Adamts2 will further reveal its role in the progression of heart failure.

Collagens are the main structural component of the extracellular matrix and provide biomechanical properties to connective tissues. A critical step in collagen fibril formation is the proteolytic removal of N- and C-terminal propeptides from procollagens by metalloproteinases of the ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) and BMP1 (bone morphogenetic protein 1)/Tolloid-like families, respectively. BMP1 also cleaves and activates the lysyl oxidase (LOX) precursor, the enzyme catalyzing the initial step in the formation of covalent collagen cross-links, an essential process for fibril stabilization. In this study, using murine skin fibroblasts and HEK293 cells, along with immunoprecipitation, LOX enzymatic activity, solid-phase binding assays, and proteomics analyses, we report that the LOX precursor is proteolytically processed by the procollagen N-proteinases ADAMTS2 and ADAMTS14 between Asp-218 and Tyr-219, 50 amino acids downstream of the BMP1 cleavage site. We noted that the LOX sequence between the BMP1- and ADAMTS-processing sites contains several conserved tyrosine residues, of which some are post-translationally modified by tyrosine O-sulfation and contribute to binding to collagen. Taken together, these findings unravel an additional level of regulation in the formation of collagen fibrils. They point to a mechanism that controls the binding of LOX to collagen and is based on differential BMP1- and ADAMTS2/14-mediated cleavage of a tyrosine-sulfated domain.

Collagen assembly during development is essential for successful matrix mineralisation, which determines bone quality and mechanocompetence. However, the biochemical and structural perturbations that drive pathological skeletal collagen configuration remain unclear. Deletion of vascular endothelial growth factor (VEGF; also known as VEGFA) in bone-forming osteoblasts (OBs) induces sex-specific alterations in extracellular matrix (ECM) conformation and mineralisation coupled to vascular changes, which are augmented in males. Whether this phenotypic dimorphism arises as a result of the divergent control of ECM composition and its subsequent arrangement is unknown and is the focus of this study. Herein, we used murine osteocalcin-specific Vegf knockout (OcnVEGFKO) and performed ex vivo multiscale analysis at the tibiofibular junction of both sexes. Label-free and non-destructive polarisation-resolved second-harmonic generation (p-SHG) microscopy revealed a reduction in collagen fibre number in males following the loss of VEGF, complemented by observable defects in matrix organisation by backscattered electron scanning electron microscopy. This was accompanied by localised divergence in collagen orientation, determined by p-SHG anisotropy measurements, as a result of OcnVEGFKO. Raman spectroscopy confirmed that the effect on collagen was linked to molecular dimorphic VEGF effects on collagen-specific proline and hydroxyproline, and collagen intra-strand stability, in addition to matrix carbonation and mineralisation. Vegf deletion in male and female murine OB cultures in vitro further highlighted divergence in genes regulating local ECM structure, including Adamts2, Spp1, Mmp9 and Lama1. Our results demonstrate the utility of macromolecular imaging and spectroscopic modalities for the detection of collagen arrangement and ECM composition in pathological bone. Linking the sex-specific genetic regulators to matrix signatures could be important for treatment of dimorphic bone disorders that clinically manifest in pathological nano- and macro-level disorganisation. This article has an associated First Person interview with the first author of the paper., Summary: Combined application of polarisation-resolved second-harmonic generation microscopy and Raman spectroscopy identified unique, sexually dimorphic extracellular matrix signatures linking pathological matrix disorganisation with composition.

The Ehlers–Danlos Syndromes (EDS) comprise a clinically and genetically heterogeneous group of complex hereditary disorders of connective tissue, with common features including joint hypermobility, soft and hyperextensible skin, abnormal wound healing, easy bruising, and signs of generalized connective tissue friability. Initial ultrastructural studies suggested that the abnormalities underlying EDS affected the collagen “wickerwork” of the connective tissue, and early biochemical and genetic studies identified defects in fibrillar types I, III, and V collagen, and in enzymes involved in their posttranslational modification, lysyl hydroxylase 1 and the procollagen amino-proteinase ADAMTS2. More recent discoveries have implicated a range of other, diverse extracellular matrix (ECM) molecules in the physiopathology of EDS, including the glycoprotein tenascin X, the FACIT type XII collagen, the intracellular chaperone and peptidylprolyl isomerase FKBP22, enzymes involved in glycosaminoglycan biosynthesis (D4ST1, DS-epi1, galactosyltransferase I and II), an intracellular zinc transporter ZIP13, (putative) transcription factors ZNF469 and PRDM5, factors involved in the classical complement pathway (C1r and C1s), and most recently, the ECM molecule AEBP1 that is involved in collagen polymerization. In this chapter, we give an overview of the different types of EDS and describe how the identification of their molecular underpinnings, and the study of pathophysiologic consequences of these defects in humans and in cellular and mouse models have provided key insights into the complex pathways of collagen fibrillogenesis and supramolecular organization of the collagen fibrils in the ECM.

N-propeptidaz izoenzimlerinden ADAMTS2 (a disintegrin and metalloproteinase with thrombospondin motifs 2), prokollajenlerin amino uclarinin kesilip uzaklastirilmasini saglayarak kollejen biyosentezinde gorev alan bir enzimdir. ADAMTS2, prokollajenlerin islenmesinin yani sira anti-anjiyojenik aktiviteye de sahiptir. Bu aktivitesi ile kanser calismalarinda bir hedef haline gelmistir. Hipoksik regulasyon hucresel duzeyde cok sayida genin ifadesini etkileyen bir surectir. Calismamiz kapsaminda ADAMTS2 geninin klonlanmasi ve ektopik olarak Saos-2 (insan kemik karsinomu) hucre hattinda ifadesi gerceklestirilmistir. Bu amacla ADAMTS2 kodlayici sekans iceren ekspresyon vektorunun, Saos-2 hucrelerine kalsiyum-fosfat presipitasyonu ile gecici transfeksiyonu gerceklestirilmistir. Rekombinant ADAMTS2’nin Saos-2 hucrelerinde ektopik olarak uretilip uretilmedigi vektor transfekte edilmeyen hucrelerdeki ADAMTS2 mRNA ifadesi ile kontrol edilmistir. Transfekte edilen Saos-2 hucrelerinde ADAMTS2 mRNA ifadesi kontrol grubuna kiyasla 50 kat artis oldugu gozlenmistir. Daha sonra rekombinant ADAMTS2’nin Saos- 2 hucrelerinin koloni olusturma potansiyeli uzerindeki etkisi hem normal hem de kimyasal olarak induklenmis hipoksik kosullarda incelenmistir. Kontrol grubu hucrelerine kiyasla normal kosullarda ektopik ifadenin saglandigi Saos-2 hucrelerinde koloni olusumu azalmistir. Ayrica Saos-2 hucrelerinde hipoksik kosullarda yapilan ektopik ifadenin hucrelerin koloni olusturma potansiyellerini uzerinde daha guclu yonde azaltici etkisi tespit edilmistir. Calismamizda, ilk kez ADAMTS2'nin hipoksik kosullarda guclu inhibe edici etkisi Saos-2 hucrelerinde belirlenmistir.

ADAMTS proteins are a superfamily of 26 secreted molecules comprising two related, but distinct families. ADAMTS proteases are zinc metalloendopeptidases, most of whose substrates are extracellular matrix (ECM) components, whereas ADAMTS-like proteins lack a metalloprotease domain, reside in the ECM and have regulatory roles vis-à-vis ECM assembly and/or ADAMTS activity. Evolutionary conservation and expansion of ADAMTS proteins in mammals is suggestive of crucial embryologic or physiological roles in humans. Indeed, Mendelian disorders or birth defects resulting from naturally occurring ADAMTS2, ADAMTS3, ADAMTS10, ADAMTS13, ADAMTS17, ADAMTS20, ADAMTSL2 and ADAMTSL4 mutations as well as numerous phenotypes identified in genetically engineered mice have revealed ADAMTS participation in major biological pathways. Important roles have been identified in a few acquired conditions. ADAMTS5 is unequivocally implicated in pathogenesis of osteoarthritis via degradation of aggrecan, a major structural proteoglycan in cartilage. ADAMTS7 is strongly associated with coronary artery disease and promotes atherosclerosis. Autoantibodies to ADAMTS13 lead to a platelet coagulopathy, thrombotic thrombocytopenic purpura, which is similar to that resulting from ADAMTS13 mutations. ADAMTS proteins have numerous potential connections to other human disorders that were identified by genome-wide association studies. Here, we review inherited and acquired human disorders in which ADAMTS proteins participate, and discuss progress and prospects in therapeutics.

Since its first description, ADAMTS14 has been considered as an aminoprocollagen peptidase based on its high similarity with ADAMTS3 and ADAMTS2. As its importance for procollagen processing was never experimentally demonstrated in vivo , we generated Adamts14 -deficient mice. They are healthy, fertile and display normal aminoprocollagen processing. They were further crossed with Adamts2 -deficient mice to evaluate potential functional redundancies between these two highly related enzymes. Initial characterizations made on young Adamts2-Adamts14 -deficient animals showed the same phenotype as that of Adamts2 -deficient mice, with no further reduction of procollagen processing and no significant aggravation of the structural alterations of collagen fibrils. However, when evaluated at older age, Adamts2-Adamts14 -deficient mice surprisingly displayed epidermal lesions, appearing in 2 month-old males and later in some females, and then worsening rapidly. Immunohistological evaluations of skin sections around the lesions revealed thickening of the epidermis, hypercellularity in the dermis and extensive infiltration by immune cells. Additional investigations, performed on young mice before the formation of the initial lesions, revealed that the primary cause of the phenotype was not related to alterations of the epidermal barrier but was rather the result of an abnormal activation and differentiation of T lymphocytes towards a Th1 profile. However, the primary molecular defect probably does not reside in the immune system itself since irradiated Adamts2-Adamts14 -deficient mice grafted with WT immune cells still developed lesions. While originally created to better characterize the common and specific functions of ADAMTS2 and ADAMTS14 in extracellular matrix and connective tissues homeostasis, the Adamts2-Adamts14 -deficient mice revealed an unexpected but significant role of ADAMTS in the regulation of immune system, possibly through a cross-talk involving mesenchymal cells and the TGFβ pathways.

Summary An eight‐week old Doberman Pinscher was diagnosed with Ehlers Danlos syndrome based on the dog's hyper‐mobile carpal, tarsal and stifle joints and abnormal skin. The skin was loose and hyper‐elastic with several wounds and large atrophic scars. The dog was euthanized after a severe degloving injury from minimal trauma. A whole‐genome sequence, generated with DNA from the dog's blood, contained a rare, homozygous C‐to‐T transition at position 2408978 on chromosome 11. This transition is predicted to alter the ADAMTS2 transcript (ADAMTS2:c.769C>T) and encode a nonsense mutation (p.Arg257Ter). Biallelic ADAMTS2 mutations have caused a type of Ehlers Danlos syndrome known as dermatosparaxis in other species.

Purpose The development of intracranial aneurysm (IA) has been linked to genetic factors. The current study examines the potential role of genes encoding disintegrin and metalloproteinase using thrombospondin motifs (ADAMTS) in IA development. Material and Methods High-throughput whole-genome and whole-exome sequencing were used when screening for deleterious single-nucleotide variants (SNVs) in ADAMTS genes using samples from 20 Han Chinese patients: 19 with familial IA and one patient with sporadic IA. The variant frequencies in these subjects were compared to those in control individuals found in the Genome Aggregation Database. Transcriptome sequencing and methylation sequencing data were retrieved from the Gene Expression Omnibus (GEO) database to identify differentially expressed ADAMTS genes and their methylation sites. We predicted the network of interactions among proteins encoded by the overlapping set of ADAMTS genes showing deleterious variants and both differential expression and abnormal methylation in IA. Possible candidate proteins linked to IA were validated using Western blot analysis. The associations between IA and SNVs rs11750568 in ADAMTS2, as well as rs2301612 and rs2285489 in ADAMTS13, were verified using the Sequenom MassArray system on a separate sample set of 595 Han Chinese patients with sporadic IA and 600 control individuals. Results A total of 16 deleterious variants in 13 ADAMTS genes were identified in our patients, and seven of these genes overlapped with the genes found to be differentially expressed and differentially methylated in the GEO database. Protein–protein interaction analysis predicted that ADAMTSL1 was at the center of the seven genes. ADAMTSL1 protein was lower expressed in IA tissue than in the control cerebral artery. Frequencies of the IA-related SNVs rs11750568 in ADAMTS2 and rs2301612 and rs2285489 in ADAMTS13 were not significantly different between sporadic IA patients and controls. Conclusion IA is associated with genetic variants, differential expression, and abnormal methylation in ADAMTS genes, ADAMTSL1 in particular.

Türkoğlu, Sümeyye Aydoğan, ADAMTS2 (a disintegrin and metalloproteinase with thrombospondin motifs 2), an N- propeptidase isoenzyme, is an enzyme involved in collagen biosynthesis by providing the amino ends of procollagen to be cut away. ADAMTS2 has anti-angiogenic activity as well as provides the processing of collagen. With this activity, it has become a target in cancer studies. Hypoxic regulation is a process that affects the expression of a large number of genes at the cellular level. Within the scope of our study, the cloning of the ADAMTS2 gene and its expression in Saos-2 (human bone carcinoma) cell line were performed ectopically. For this purpose, the transient transfection of the expression vector containing ADAMTS2 coding sequence was transfected by the calcium-phosphate precipitation method. Recombinant ADAMTS2 mRNA expression was checked by Real-Time PCR in Saos-2 cells. It was observed that there was a 50-fold increase in ADAMTS2 mRNA expression in the transfected Saos-2 cells compared to the control group. Then, the effect of recombinant ADAMTS2 on the colony-forming potential of Saos-2 cells was investigated in both normal and chemically induced hypoxic conditions. Colony formation was reduced in Saos-2 cells, in which ADAMTS2 was expressed ectopically under normal conditions compared to control group cells. Also, a stronger reducing effect on the colony-formation potential of ectopic expression in hypoxic conditions in Saos-2 cells was determined. In this study, the strong inhibitory effect of ADAMTS2 in hypoxic conditions was determined in Saos-2 cells for the first time., N-propeptidaz izoenzimlerinden ADAMTS2 (a disintegrin and metalloproteinase with thrombospondin motifs 2), prokollajenlerin amino uçlarının kesilip uzaklaştırılmasını sağlayarak kollejen biyosentezinde görev alan bir enzimdir. ADAMTS2, prokollajenlerin işlenmesinin yanı sıra anti-anjiyojenik aktiviteye de sahiptir. Bu aktivitesi ile kanser çalışmalarında bir hedef haline gelmiştir. Hipoksik regülasyon hücresel düzeyde çok sayıda genin ifadesini etkileyen bir süreçtir. Çalışmamız kapsamında ADAMTS2 geninin klonlanması ve ektopik olarak Saos-2 (insan kemik karsinomu) hücre hattında ifadesi gerçekleştirilmiştir. Bu amaçla ADAMTS2 kodlayıcı sekans içeren ekspresyon vektörünün, Saos-2 hücrelerine kalsiyum-fosfat presipitasyonu ile geçici transfeksiyonu gerçekleştirilmiştir. Rekombinant ADAMTS2’nin Saos-2 hücrelerinde ektopik olarak üretilip üretilmediği vektör transfekte edilmeyen hücrelerdeki ADAMTS2 mRNA ifadesi ile kontrol edilmiştir. Transfekte edilen Saos-2 hücrelerinde ADAMTS2 mRNA ifadesi kontrol grubuna kıyasla 50 kat artış olduğu gözlenmiştir. Daha sonra rekombinant ADAMTS2’nin Saos- 2 hücrelerinin koloni oluşturma potansiyeli üzerindeki etkisi hem normal hem de kimyasal olarak indüklenmiş hipoksik koşullarda incelenmiştir. Kontrol grubu hücrelerine kıyasla normal koşullarda ektopik ifadenin sağlandığı Saos-2 hücrelerinde koloni oluşumu azalmıştır. Ayrıca Saos-2 hücrelerinde hipoksik koşullarda yapılan ektopik ifadenin hücrelerin koloni oluşturma potansiyellerini üzerinde daha güçlü yönde azaltıcı etkisi tespit edilmiştir. Çalışmamızda, ilk kez ADAMTS2'nin hipoksik koşullarda güçlü inhibe edici etkisi Saos-2 hücrelerinde belirlenmiştir.

RESUMEN: El conocimiento de los mecanismos moleculares implicados en el desarrollo y las manifestaciones clínicas de la esquizofrenia pueden mejorar nuestra capacidad para diagnosticarlo y tratarlo. Datos previos asociaron la desregulación de ADAMTS2 en PBMCs de pacientes en FEP, así como en respondedores clínicos a AP. En esta tesis, realizamos una validación independiente de dichos datos y estudiamos los mecanismos implicados en el control de ADAMTS2. Verificamos nuestros resultados previos utilizando una nueva cohorte de pacientes con esquizofrenia con seguimiento clínico tras el tratamiento. Además, ADAMTS2 se activó mediante señalización de receptores de clase D1 y señalización CREB / ERK, que fue derogada in vitro mediante AP e inhibidores de PKA/NEK. En conclusión, receptores D1 y activación de CREB podrían participar en el inicio y respuesta clínicas a la terapia, controlando la expresión y actividad de ADAMTS2, y proporcionando un nuevo panorama de mejorar de su eficacia clínica. ABSTRACT: Molecular mechanisms in the development and clinical manifestations of schizophrenia can improve our ability to diagnose and treat it. Previous data associated ADAMTS2 expression deregulation in PBMCs from patients at FEP (up) as well as in clinical responders to APs (down). In this thesis, we performed an independent validation of such data and studied the mechanisms implicated in the control of ADAMTS2. Using a new cohort of drug-naïve schizophrenia patients with clinical follow-up, we confirmed our previous data. Also, ADAMTS2 was activated by D1-class receptors signalling and downstream by CREB/ERK signalling. APs and selective PKA/MEK inhibitors abrogated D1-mediated activation of ADAMTS2 in vitro. Thus, D1 receptors signalling towards CREB activation might participate in the onset and clinical responses to therapy in schizophrenia, by controlling ADAMTS2 expression and activity. The unbiased investigation of molecular mechanisms triggered by APs may provide a new landscape of novel targets potentially associated with clinical efficacy. La financiación necesaria para la realización de esta Tesis doctoral ha sido aportada por el MINECO mediante los proyectos SAF2013-46292-R y SAF2016-76046-R, y por el ISCII mediante el Proyecto PI16/00156 y la financiación específica al grupo de investigación CIBERSAM-G26. El autor de esta tesis ha disfrutado de contrato predoctoral de Formación de Personal Investigador (FPI), referencia BES-2014-070615, concedida por el MINECO, y de un contrato de 6 meses mediante la ayuda de Luchamos por la Vida 2019 en el Instituto de Investigación Marqués de Valdecilla (IDIVAL).

ADAMTS constitute a family of 19 secreted metalloproteinases involved in diverse physiopathological conditions. Most of their roles first emerged from analysis of spontaneous human and animal mutations or genetically engineered animals. However, the involved mechanisms and the full repertoire of their functions are still largely unrecognized, in part because they are difficult to produce and purify as recombinant active enzymes. Here we describe protocols, tips, and tricks specifically regarding ADAMTS2, 3, and 14 but still relevant for other ADAMTS.

OBJECTIVE Cerebral aneurysms (CAs) affect 2%–5% of the population, and familial predisposition plays a significant role in CA pathogenesis. Several lines of evidence suggest that genetic variations in matrix metalloproteinase genes (MMP) are involved in the etiopathology of CAs. The authors performed a case-control study to investigate the effect of 4 MMP variants from the ADAMTS family on the pathogenesis of CAs. METHODS To identify susceptible genetic variants, the authors investigated 8 single nucleotide polymorphisms (SNPs) in 4 genes from the ADAMTS family (ADAMTS2, -7, -12, and -13) known to be associated with vascular diseases. The study included 353 patients with CAs and 1055 healthy adults. RESULTS The authors found significant associations between CA susceptibility and genetic variations in 3 members of the ADAMTS family. The largest risk for CA (OR 1.32, p = 0.006) was observed in carriers of the ADAMTS2 variant rs11750568, which has been previously associated with pediatric stroke. Three SNPs under investigation are associated with a protective effect in CA pathogenesis (ADAMTS12 variant rs1364044: OR 0.65, p = 0.0001; and ADAMTS13 variants rs739469 and rs4962153: OR 0.77 and 0.63, p = 0.02 and 0.0006, respectively), while 2 other ADAMTS13 variants may confer a significant risk (rs2301612: OR 1.26, p = 0.011; rs2285489: OR 1.24, p = 0.02). CONCLUSIONS These results suggest that reduced integrity of the endothelial wall, as conferred by ADAMTS variants, together with inflammatory processes and defective vascular remodeling plays an important role in CA pathogenesis, although the mechanism of action remains unknown. The authors' findings may lead to specific screening of at-risk populations in the future.

Cartilage degeneration is believed to be the primary event in the development of osteoarthritis (OA). On the other hand, meniscal degeneration is observed with high prevalence, and some researchers have pointed out that pathological changes in menisci precede that of cartilage. The purpose of the present study is to investigate comprehensive gene expression pattern of cartilage and menisci in the initial phase of surgically induced OA and to compare them. Secondary OA was surgically induced in 10-week-old male Wistar rats by anterior cruciate ligament transection (ACLT). Articular cartilage and menisci were separately dissected from six ACLT- and six sham-operated rats. Each specimen was analyzed by microarray, histological, and immunohistochemical analysis 3 weeks after surgery. Of the 36,685 transcripts detectable by microarray, the number of upregulated transcripts in ACLT menisci was >2.5-fold compared with that in ACLT menisci in any given threshold. Cluster analysis using the Database for Annotation Visualization and Integrated Discovery (DAVID) showed genes related to OA, such as response to stimulus, angiogenesis, and apoptosis, which were predominantly found in menisci in ACLT rats. Representative proteases including Adamts2, 4, Mmp2, 12, 13, 14, 16, extracellular matrix genes including versican (Vcan), lumican (Lum), syndecan1 (Sdc1), and Prostaglandin endoperoxide synthase2 (Ptgs2) were up-regulated in menisci, but were not up-regulated in cartilage. Our results indicated that the molecular changes that occurred in menisci preceded those occurred in cartilage in the very early phase of surgically induced OA models.

Made available in DSpace on 2014-09-30T18:18:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-05-01Bitstream added on 2014-10-01T14:04:10Z : No. of bitstreams: 1 S0100-736X2014000500010.pdf: 1325621 bytes, checksum: b616649d5b9e2fc531104505ac1b006a (MD5) Dermatosparaxia em animais é uma doença autossômica recessiva do tecido conjuntivo caracterizada por fragilidade e hiperextensibilidade cutânea. A doença em ovinos White Dorper é provocada pela mutação c.421G>T no gene ADAMmetalopeptidase com trombospondina tipo 1 motif, 2 (ADAMTS2). O objetivo deste estudo foi descrever os achados clínicos, moleculares e histopatológicos da dermatosparaxia em ovinos White Dorper de um rebanho localizado no Centro-Oeste Paulista. O rebanho era composto por nove animais, sendo um reprodutor, quatro matrizes e seus respectivos borregos. Dos nove animais examinados, dois apresentavam sinais clínicos compatíveis com dermatosparaxia. O exame histopatológico de amostras cutâneas das lesões destes dois animais revelou também achados compatíveis com dermatosparaxia, sendo caracterizados por epiderme e anexos cutâneos preservados e sem características atípicas; colágeno displásico arranjado em feixes pequenos, fragmentados e com focos de degeneração, anexos cutâneos proeminentes e na região da derme foco hemorrágico intenso associado a moderado infiltrado neutrofílico na derme profunda. Com o objetivo de realizar o diagnóstico molecular da enfermidade, uma PCR foi padronizada utilizando primers específicos desenhados para amplificar a região do gene ADAMTS2 que continha a mutação c.421G>T e o DNA obtido de amostras de sangue de todos os animais do rebanho. O sequenciamento direto dos produtos da PCR, comprovou que os dois animais clinicamente afetados possuíam a mutação responsável pela dermatosparaxia. A metodologia descrita neste estudo possibilitou o diagnóstico definitivo da doença. Segundo a literatura consultada, esta é a primeira vez que a dermatosparaxia é descrita em ovinos White Dorper no Brasil. A metodologia aqui descrita poderá ser empregada em estudos futuros que avaliem a prevalência desta mutação no Brasil, possibilitando a adoção de medidas que previnam a disseminação dessa mutação no rebanho brasileiro de ovinos White Dorper. Dermatosparaxis in animals is an autosomal recessive disorder of the connective-tissue clinically characterized by skin fragility and hiperextensibility. The disease in White Dorper sheep is caused by mutation (c.421G>T) in the ADAM metalloproteinase with thrombospondin type 1 motif, 2 (ADAMTS2) gene. This study describes the dermatological, histological and the molecular findings of the dermatosparaxis in White Dorper sheep from a herd located in the center-west of São Paulo State. The herd consisted of one ram, four ewe and their lambs. In this herd two lambs had clinical signs consistent with dermatosparaxis. Histopathological evaluation of the affected skin of these two animals also revealed consistent findings with dermatosparaxis, characterized by dysplasia of the collagen, which were arranged in small and fragmented collagen bundles and with foci of degeneration of collagen. Prominent cutaneous appendages and severe hemorrhagic focus in dermis region associated with mild neutrophilic infiltrate in the deep dermis. PCR using DNA blood and specific primers to amplify the mutation region c.421G>T was optimized in order to perform molecular diagnosis of the disease. The direct sequencing of the PCR products proved that the two clinically affected animals had the mutation responsible for dermatosparaxis, previously described for this breed and allowed the definitive diagnosis of the disease. This is the first report of the dermatosparaxis in White Dorper sheep in Brazil and the methodology used to confirm the diagnosis could be used in future studies to assess the prevalence of this mutation in Brazil, allowing the adoption of measures to prevent the spread of this mutation in the Brazilian White Dorper herd. Universidade Estadual Paulista Faculdade de Medicina Veterinária e Zootecnia Departamento de Clínica Veterinária Universidade Estadual Paulista Faculdade de Medicina Veterinária e Zootecnia Departamento de Clínica Veterinária

A disintegrin and metalloproteinases (ADAMs are members of the metzinci nf amily of zinc‑dependent metalloproteinases that play pivotal roles in the proteolytic degradation of the extracellular matrix for cell invasion. Few studies have investigated the ADAM subtypes that are expressed in first trimester trophoblast cells. The purpose of this study was to elucidate the differential expression profiles of ADAMs between first trimester villous trophoblast cells (VTs and extravillous trophoblast cells (EVTs. We isolated EVTs from explanted human first trimester chorionic villi and investigated the mRNA expression levels of five members of the ADAM family (ADAMTS1 ADAMTS2 ADAM10 ADAM12 andADAM17 using real‑time PCR. Chorionic villous tips were defined as first trimester VTs. Of the differentially expressed ADAM genes between first trimester VTs and EVTs ADAMTS1 was expressed at a significantly higher level in EVTs than in VTs. In contrast both ADAM10 and ADAM12 were expressed at significantly higher levels in VTs than in EVTs. No differences were found in the mRNA levels of ADAMTS2 and ADAM17 between the two cell types. Moreover we demonstrated that in VTs the expression level of ADAM12 was significantly downregulated in the late first trimester (10―13 gestational weeks compared to the middle first trimester (7―8 weeks. These results suggest that first trimester trophoblast cells express ADAM genes in cell type‑ and gestational age‑dependent manners. Our data provide additional insight into the functions of ADAMs in the human placenta. (J Nippon Med Sch 2014; 81: 122―129

Rupture of the extraembryonic membranes that form the gestational sac in humans is a typical feature of human parturition. However, preterm premature rupture of membranes (PPROM) occurs in approximately 1% of pregnancies, and is a leading cause of preterm birth. Conversely, retention of an intact gestational sac during parturition in the form of a caul is a rare occurrence. Understanding the molecular and evolutionary underpinnings of these disparate phenotypes can provide insight into both normal pregnancy and PPROM. Using phylogenetic techniques we reconstructed the evolution of the gestational sac phenotype at parturition in 55 mammal species representing all major viviparous mammal groups. We infer the ancestral state in therians, eutherians, and primates, as in humans, is a ruptured gestational sac at parturition. We present evidence that intact membranes at parturition have evolved convergently in diverse mammals including horses, elephants, and bats. In order to gain insight into the molecular underpinnings of the evolution of enhanced membrane integrity we also used comparative genomics techniques to reconstruct the evolution of a subset of genes implicated in PPROM, and find that four genes (ADAMTS2, COL1A1, COL5A1, LEPRE1) show significant evidence of increased nonsynonymous rates of substitution on lineages with intact membranes as compared to those with ruptured membranes. Among these genes, we also discovered that 17 human SNPs are associated with or near amino acid replacement sites in those mammals with intact membranes. These SNPs are candidate functional variants within humans, which may play roles in both PPROM and/or the retention of the gestational sac at birth., Highlights • We reconstructed the evolution of the gestational sac at parturition in mammals. • We offer evidence that intact membranes during parturition evolved multiple times. • Four genes show increased nonsynonymous rates on lineages with intact membranes. • Human SNPs are near amino acid replacements sites in mammals with intact membranes. • SNPs near amino acid changes in certain species may play a role in sac integrity.

Extracellular matrix (ECM) is the major macromolecule in skeletal muscle, and collagen is main component of ECM surrounding muscle fiber and adipocyte, which affect meat quality greatly. The remodeling of ECM is regulated by matrix metalloproteinases, such as ADAMTS2, which is essential for the maturation of triple helical collagen fibrils in body. The expression patterns of COL1A1, COL2A1, COL3A1 and ADAMTS2 in longissimus dorsi muscle were explored by qRT-PCR and results indicated that the expression levels of COL1A1, COL3A1 and ADAMTS2 were significantly higher at 3 and 24 month, while significantly lower at 12 and 30 month. The expression of ADAMTS2 and COL1A1 had significant positive relationships with intramuscular fat content, while expression of COL3A1 had significant positive relationship with shearing force and water holding capacity in cattle. The expression levels of collagen and ADAMTS2 were significantly higher in mesenteric fat, mammary fat pad and subcutaneous fat than in longissimus dorsi muscle, biceps femoris and infraspinitus tissues. The expressions levels of COL1A1, COL3A1 and ADAMTS2 were significantly lower in marbling fat than in other fat tissues. This study indicated that the expression of collagen and ADAMTS2 had important effects on postnatal skeletal muscle development and meat quality.

ADAMTS2 (A Disintegrin and Metalloproteinase With Thrombospondin Motifs 2) is recognized as a metalloproteinase that promotes the cleavage of amino propeptides of types I, II, III, and V procollagens. However, the role of ADAMTS2 in the heart has not yet been defined. Herein, we observed the upregulated expression of ADAMTS2 in failing human hearts and hypertrophic murine hearts. Mice lacking ADAMTS2 display exacerbated cardiac hypertrophy on pressure overload–induced hypertrophic response, whereas mice with cardiac-specific overexpression of ADAMTS2 display alleviation of this detrimental phenotype. Consistent with these results, in vitro loss or gain of function experiments in neonatal rat cardiomyocytes confirmed that ADAMTS2 negatively regulates cardiomyocyte hypertrophy in response to Ang II. Mechanistically, blockage of the PI3K (phosphoinositide 3-kinase)/AKT (protein kinase B)–dependent signaling pathway with specific inhibitors both in vivo and in vitro could rescue the aggravated hypertrophic response to the loss of ADAMTS2. Collectively, we propose that ADAMTS2 regulates the hypertrophic response through inhibiting the activation of the PI3K/AKT-dependent signaling pathway. Because ADAMTS2 is an extracellular protein, it could be effectively manipulated using pharmacological means to modulate cardiac hypertrophy.

A disintegrin and metalloproteinase with thrombospondin type I motif (ADAMTS)2, 3, and 14 are collectively named procollagen N-proteinases (pNPs) because of their specific ability to cleave the aminopropeptide of fibrillar procollagens. Several reports also indicate that they could be involved in other biological processes, such as blood coagulation, development, and male fertility, but the potential substrates associated with these activities remain unknown. Using the recently described N-terminal amine isotopic labeling of substrate approach, we analyzed the secretomes of human fibroblasts and identified 8, 17, and 22 candidate substrates for ADAMTS2, 3, and 14, respectively. Among these newly identified substrates, many are components of the extracellular matrix and/or proteins related to cell signaling such as latent TGF-β binding protein 1, TGF-β RIII, and dickkopf-related protein 3. Candidate substrates for the 3 ADAMTS have been biochemically validated in different contexts, and the implication of ADAMTS2 in the control of TGF-β activity has been further demonstrated in human fibroblasts. Finally, the cleavage site specificity was assessed showing a clear and unique preference for nonpolar or slightly hydrophobic amino acids. This work shows that the activities of the pNPs extend far beyond the classically reported processing of the aminopropeptide of fibrillar collagens and that they should now be considered as multilevel regulators of matrix deposition and remodeling.-Bekhouche, M., Leduc, C., Dupont, L., Janssen, L., Delolme, F., Vadon-Le Goff, S., Smargiasso, N., Baiwir, D., Mazzucchelli, G., Zanella-Cleon, I., Dubail, J., De Pauw, E., Nusgens, B., Hulmes, D. J. S., Moali, C., Colige, A. Determination of the substrate repertoire of ADAMTS2, 3, and 14 significantly broadens their functions and identifies extracellular matrix organization and TGF-β signaling as primary targets.

Purpose Keratoconus (KC) is a multifactorial disease where progressive thinning and weakening of the cornea leads to loss of visual acuity. Although the underlying etiology is poorly understood, a major endpoint is a dysfunctional stromal connective tissue matrix. Using multiple individual KC corneas, we determined that matrix production by keratocytes is severely impeded due to an altered stress response program. Methods KC and donor (DN) stromal keratocytes were cultured in low glucose serum-free medium containing insulin, selenium and transferrin. Fibronectin, collagens and proteins related to their chaperone, processing and export, matrix metalloproteinase, and stress response related proteins were investigated by immunoblotting, immunocytochemistry, hydroxyproline quantification, and gelatin zymography. Multiplexed mass spectrometry was used for global proteomic profiling of 5 individual DN and KC cell culture. Transcription of selected proteins was assayed by qPCR. Results DN and KC cells showed comparable survival and growth. However, immunoblotting of selected ECM proteins and global proteomics showed decreased fibronectin, collagens, PCOLCE, ADAMTS2, BMP1, HSP47, other structural and cytoskeletal proteins in KC. Phosphorylated (p) eIF2α, a translation regulator and its target, ATF4 were increased in KC cultured cells and corneal sections. Conclusions The profound decrease in structural proteins in cultured KC cells and increase in the p-eIF2α, and ATF4, suggest a stress related blockade in structural proteins not immediately needed for cell survival. Therefore, this cell culture system reveals an intrinsic aggravated stress response with consequent decrease in ECM proteins as potential pathogenic underpinnings in KC.

We describe a newborn infant with multiple congenital skull fractures and intracranial hemorrhage. He also had multiple skin folds suggesting a connective tissue abnormality. Electron microscopy of the skin biopsy showed collagen abnormalities with a "hieroglyphic appearance." The analysis of the synthesis of collagen in the cultured dermal fibroblasts demonstrated an accumulation of procollagen I. Molecular analysis found a nonsense mutation Q225X in ADAMTS2 gene, which encodes procollagen I N-terminal proteinase. All these findings confirmed the diagnosis of Ehlers-Danlos syndrome type VIIC (MIM 225410). Family studies suggested a founder effect in Ashkenazi Jews originating from Belarus. Prenatal diagnosis in the subsequent pregnancy reassured the parents that the fetus was an unaffected carrier.

Dermatosparaxis is an autosomal recessive disorder of connective tissue; the disorder is clinically characterized by skin fragility and hyperextensibility. Dermatosparaxis in White Dorper sheep is caused by a single nucleotide polymorphism (SNP) (c.421G>T) in the ADAM metalloproteinase with thrombospondin type 1 motif, 2 (ADAMTS2) gene. The aim of this study was to investigate the prevalence of this SNP in a White Dorper herd in São Paulo state, Brazil. In this study, we collected blood DNA samples from 303 White Dorper sheep and performed polymerase chain reaction to amplify the SNP region. The samples were sequenced to determine the presence of the SNP in the ADAMTS2 gene. The SNP prevalence in the studied population was 15.5%; this finding indicates that more effective control measures should be used to prevent the inheritance of SNP c.421G>T in the ADAMTS2 gene in Brazilian White Dorper herds. Resumo: A dermatosparaxia é uma doença autossômica recessiva do tecido conjuntivo, clinicamente caracaterizada pela fragilidade e hiperextensibilidade da pele. A dermatosparaxia em ovinos White Dorper é causada pelo polimorfismo de base única (SNP) c.421G>T no gene ADAM metalopeptidase com trombospondina tipo 1 motif, 2 (ADAMTS2). O objetivo deste estudo foi investigar a prevalência deste SNP em ovinos White Dorper no estado de São Paulo, Brasil. Foram coletadas amostras de sangue de 303 ovinos White Dorper. O DNA foi purificado destas amostras sanguíneas e utilizado em uma reação em cadeia da polimerase (PCR) para amplificação da região do gene contendo SNP c.421G>T. Os produtos das PCR foram sequenciados para determinar o genótipo dos animais. A prevalência do SNP na população estudada foi de 15,5%, estes achados indicam que medidas de controle efetivas devem ser utilizadas para prevenir a disseminação deste SNP no rebanho brasileiro de White Dorper.

PURPOSE: The Ehlers-Danlos syndrome (EDS), dermatosparaxis type, is a recessively inherited connective tissue disorder caused by deficient activity of ADAMTS-2, an enzyme that cleaves the aminoterminal propeptide domain of types I, II, and III procollagen. Only 10 EDS dermatosparaxis patients have been reported, all presenting a recognizable phenotype with characteristic facial gestalt, extreme skin fragility and laxity, excessive bruising, and sometimes major complications due to visceral and vascular fragility. METHODS: We report on five new EDS dermatosparaxis patients and provide a comprehensive overview of the current knowledge of the natural history of this condition. RESULTS: We identified three novel homozygous loss-of-function mutations (c.2927_2928delCT, p.(Pro976Argfs*42); c.669_670dupG, p.(Pro224Argfs*24); and c.2751-2A>T) and one compound heterozygous mutation (c.2T>C, p.? and c.884_887delTGAA, p.(Met295Thrfs26*)) in ADAMTS2 in five patients from four unrelated families. Three of these displayed a phenotype that was strikingly milder than that of previously reported patients. CONCLUSION: This study expands the clinical and molecular spectrum of the dermatosparaxis type of EDS to include a milder phenotypic variant and stresses the importance of good clinical criteria. To address this, we propose an updated set of criteria that accurately captures the multisystemic nature of the dermatosparaxis type of EDS.Genet Med advance online publication 14 January 2016Genetics in Medicine (2016); doi:10.1038/gim.2015.188.

Adverse remodeling of the extracellular matrix (ECM) is a significant characteristic of heart failure. Reverse remodeling of the fibrillar ECM secondary to mechanical unloading of the left ventricle (LV) by left ventricular assist device (LVAD) has been subject of intense investigation; however, little is known about the impacts on nonfibrillar ECM and matricellular proteins that also contribute to disease progression. Explanted failing hearts were procured from patients with nonischemic dilated cardiomyopathy (DCM) with or without LVAD support, and compared to nonfailing control hearts. LV free wall specimens were formalin-fixed, flash-frozen or optimum cutting temperature-mount frozen. Histologic and biochemical assessment of fibrillar ECM showed that LVAD support was associated with lower levels of insoluble collagen, collagen type I mRNA, and collagen I/III ratio compared with no-LVAD hearts. A disintegrin and Metalloproteinase with Thrombospondin Motifs-2 (ADAM-TS2), a procollagen endopeptidase, was reduced in no-LVAD but not in LVAD hearts. The rise in ECM proteolytic activities was significantly lower in LVAD hearts. Matrix metalloproteinases (MMP1, MMP2, MMP8, MMP13, and MT1-MMP/MMP14) were comparable between DCM hearts. Tissue inhibitor of metalloproteinase (TIMP)3 and TIMP4 messenger RNA and protein showed the greatest reduction in no-LVAD hearts. Basement membrane proteins exhibited less severe disarray of laminin and fibronectin-1 in LVAD-supported hearts. The rise in matricellular protein, osteopontin, was suppressed in LVAD hearts, whereas secreted protein, acidic, cysteine-rich (SPARC) levels was unaffected by LVAD. Mechanical unloading of the failing DCM hearts can restore the fibrillar ECM and the basement membrane, contributing toward improved clinical outcomes. However, persistent elevation of matricellular proteins such as SPARC could contribute to the relapse of failing hearts on removal of LVAD support.

The only documented activity of a subclass of ADAMTS proteases comprising ADAMTS2, 3 and 14 is the cleavage of the aminopropeptide of fibrillar procollagens. A limited number of in vitro studies suggested that ADAMTS3 is mainly responsible for procollagen II processing in cartilage. Here, we created an ADAMTS3 knockout mouse (Adamts3−/−) model to determine in vivo the actual functions of ADAMTS3. Heterozygous Adamts3+/− mice were viable and fertile, but their intercrosses demonstrated lethality of Adamts3−/− embryos after 15 days of gestation. Procollagens I, II and III processing was unaffected in these embryos. However, a massive lymphedema caused by the lack of lymphatics development, an abnormal blood vessel structure in the placenta and a progressive liver destruction were observed. These phenotypes are most probably linked to dysregulation of the VEGF-C pathways. This study is the first demonstration that an aminoprocollagen peptidase is crucial for developmental processes independently of its primary role in collagen biology and has physiological functions potentially involved in several human diseases related to angiogenesis and lymphangiogenesis. Electronic supplementary material The online version of this article (doi:10.1007/s10456-015-9488-z) contains supplementary material, which is available to authorized users.

Mutations in ADAMTS2, a procollagen amino-propeptidase, cause severe skin fragility, designated as dermatosparaxis in animals, and a subtype of the Ehlers-Danlos syndrome (dermatosparactic type or VIIC) in humans. Not all collagen-rich tissues are affected to the same degree, which suggests compensation by the ADAMTS2 homologs ADAMTS3 and ADAMTS14. In situ hybridization of Adamts2, Adamts3 and Adamts14 , and of the genes encoding the major fibrillar collagens, Col1a1, Col2a1 and Col3a1 , during mouse embryogenesis, demonstrated distinct tissue-specific, overlapping expression patterns of the protease and substrate genes. Adamts3 , but not Adamts2 or Adamts14 , was co-expressed with Col2a1 in cartilage throughout development, and with Col1a1 in bone and musculotendinous tissues. ADAMTS3 induced procollagen I processing in dermatosparactic fibroblasts, suggesting a role in procollagen I processing during musculoskeletal development. Adamts2 , but not Adamts3 or Adamts14 , was co-expressed with Col3a1 in many tissues including the lungs and aorta, and Adamts2 -/- mice showed widespread defects in procollagen III processing. Adamts2 -/- mice had abnormal lungs, characterized by a decreased parenchymal density. However, the aorta and collagen fibrils in the aortic wall appeared normal. Although Adamts14 lacked developmental tissue-specific expression, it was co-expressed with Adamts2 in mature dermis, which possibly explains the presence of some processed skin procollagen in dermatosparaxis. The data show how evolutionarily related proteases with similar substrate preferences may have distinct biological roles owing to tissue-specific gene expression, and provide insights into collagen biosynthesis and the pathobiology of dermatosparaxis.

The metalloproteinase ADAMTS-2 has procollagen I N-proteinase activity capable of cleaving procollagens I and II N-propeptides in vitro, whereas mutations in the ADAMTS-2 gene in dermatosparaxis and Ehlers-Danlos syndrome VIIC show this enzyme to be responsible in vivo for most biosynthetic processing of procollagen I N-propeptides in skin. Yet despite its important role in the regulation of collagen deposition, information regarding regulation and substrate specificity of ADAMTS-2 has remained sparse. Here we demonstrate that ADAMTS-2 can, like the procollagen C-proteinases, be regulated by transforming growth factor-β1 (TGF-β1), with implications for mechanisms whereby this growth factor effects net increases in formation of extracellular matrix. TGF-β1 induced ADAMTS-2 mRNA ∼8-fold in MG-63 osteosarcoma cells in a dose- and time-dependent, cycloheximide-inhibitable manner, which appeared to operate at the transcriptional level. Secreted ADAMTS-2 protein induced by TGF-β1 was 132 kDa and was identical in size to the fully processed, active form of the protease. Biosynthetic processing of ADAMTS-2 to yield the 132-kDa form is shown to be a two-step process involving sequential cleavage by furin-like convertases at two sites. Surprisingly, purified recombinant ADAMTS-2 is shown to cleave procollagen III N-propeptides as effectively as those of procollagens I and II, whereas processing of procollagen III is shown to be decreased in Ehlers-Danlos VIIC. Thus, the dogma that procollagen I and procollagen III N-proteinase activities are provided by separate enzymes appears to be false, whereas the phenotypes of dermatosparaxis and Ehlers-Danlos VIIC may arise from defects in both type I and type III collagen biosynthesis.

ADAMTS13 is an idiosyncratic member of a distinct family of zinc metalloproteases, the ADAMTS family. This 19-member family is related to ADAM proteases and matrix metalloproteinases (MMPs) through sequence homology of their active sites and similar catalytic domain structures. These similarities contrast with the presence of distinct ancillary domains in each family, with those of ADAMTS proteases comprising thrombospondin type 1 repeats and other modules in a characteristic arrangement. Human and animal mutations affecting ADAMTS proteases lead to a variety of inherited human disorders and animal phenotypes, which demonstrate their requirement in crucial biological and disease pathways. ADAMTS proteases are implicated in procollagen maturation (ADAMTS2, ADAMTS3), versican turnover during embryogenesis (ADAMTS1, ADAMTS5, ADAMTS9, ADAMTS15, ADAMTS20) and ovulation (ADAMTS1), cartilage aggrecan destruction in arthritis (ADAMTS4, ADAMTS5), genetic disorders affecting fibrillin microfibrils (ADAMTS10, ADAMTS17), and, recently, VEGF-C processing during lymphangiogenesis (ADAMTS3). Although ADAMTS13 shares many characteristics with the other family members, it has some special attributes and is the only ADAMTS protease presently implicated in hemostasis. Its unique specificity for von Willebrand factor contrasts with that of other family members, which can have shared or multiple substrates.

Background: Mixed phenotype acute leukemias (MPAL) include acute leukemias with blasts that express antigens of more than one lineage, with no clear evidence of myeloid or lymphoid lineage differentiation. T/myeloid (T/My) MPAL not otherwise specified (NOS) is a rare leukemia that expresses both T and myeloid antigens, accounting for less than 1% of all leukemias but 89% of T/My MPAL. From a molecular point of view, very limited data are available on T/My MPAL NOS. Case presentation: In this report we describe a T/My MPAL NOS case with a complex rearrangement involving chromosomes 5 and 14, resulting in overexpression of the ADAM metallopeptidase with thrombospondin type 1 motif, 2 (ADAMTS2) gene due to its juxtaposition to the T cell receptor delta (TRD) gene segment. Conclusion: Detailed molecular cytogenetic characterization of the complex rearrangement in the reported T/My MPAL case allowed us to observe ADAMTS2 gene overexpression, identifying a molecular marker that may be useful for monitoring minimal residual disease. To our knowledge, this is the first evidence of gene dysregulation due to a chromosomal rearrangement in T/My MPAL NOS.

Collagen fibers are the main components of most of the extracellular matrices where they provide a structural support to cells, tissues and organs. Fibril-forming procollagens are synthetized as individual chains that associate to form homo- or hetero-trimers. They are characterized by the presence of a central triple helical domain flanked by amino and carboxy propeptides. Although there are some exceptions, these two propeptides have to be proteolytically removed to allow the almost spontaneous assembly of the trimers into collagen fibrils and fibers. While the carboxy-propeptide is mainly cleaved by proteinases from the tolloid family, the amino-propeptide is usually processed by procollagen N-proteinases: ADAMTS2, 3 and 14. This review summarizes the current knowledge concerning this subfamily of ADAMTS enzymes and discusses their potential involvement in physiopathological processes that are not directly linked to fibrillar procollagen processing.

ADAMTS (a disintegrin-like and metalloproteinase domain with thrombospondin type 1 modules) proteins constitute a family of zinc metalloproteinases which target and process extracellular matrix proteins. We cloned and characterized a novel human ADAMTS gene, ADAMTS14, which is located on human chromosome 10q2. ADAMTS14 exhibits the characteristic multidomain structure of ADAMTS proteins including four thrombospondin modules and shows highest similarity to ADAMTS3 and ADAMTS2. By RT-PCR analysis we demonstrated that ADAMTS14 is expressed in human retina and also at low levels in adult brain, lung and placenta.

The amino and carboxyl propeptides of procollagens I and II are removed by specific enzymes as a prerequisite for fibril assembly. Null mutations in procollagen I N-propeptidase (ADAMTS-2) cause dermatosparaxis in cattle and the Ehlers-Danlos syndrome (dermatosparactic type) in humans by preventing proteolytic excision of the N-propeptide of procollagen I. We have found that procollagen II is processed normally in dermatosparactic nasal cartilage, suggesting the existence of another N-propeptidase(s). We investigated such a role for ADAMTS-3 in Swarm rat chondrosarcoma RCS-LTC cells, which fail to process the procollagen II N-propeptide. Stable transfection of RCS-LTC cells with bovine ADAMTS-2 or human ADAMTS-3 partially rescued the processing defect, suggesting that ADAMTS-3 has procollagen II N-propeptidase activity. Human skin and skin fibroblasts showed 30-fold higher mRNA levels of ADAMTS-2 than ADAMTS-3, whereas ADAMTS-3 mRNA was 5-fold higher than ADAMTS-2 mRNA in human cartilage. We propose that both ADAMTS-2 and ADAMTS-3 process procollagen II, but ADAMTS-3 is physiologically more relevant, given its preferred expression in cartilage. The findings provide an explanation for the sparing of cartilage in dermatosparaxis and, perhaps, for the relative sparing of some procollagen I-containing tissues.

Summary Ehlers-Danlos syndrome (EDS) type VIIC is a recessively inherited connective-tissue disorder, characterized by extreme skin fragility, characteristic facies, joint laxity, droopy skin, umbilical hernia, and blue sclera. Like the animal model dermatosparaxis, EDS type VIIC results from the absence of activity of procollagen I N-proteinase (pNPI), the enzyme that excises the N-propeptide of type I and type II procollagens. The pNPI enzyme is a metalloproteinase containing properdin repeats and a cysteine-rich domain with similarities to the disintegrin domain of reprolysins. We used bovine cDNA to isolate human pNPI. The human enzyme exists in two forms: a long version similar to the bovine enzyme and a short version that contains the Zn ++ -binding catalytic site but lacks the entire C-terminal domain in which the properdin repeats are located. We have identified the mutations that cause EDS type VIIC in the six known affected human individuals and also in one strain of dermatosparactic calf. Five of the individuals with EDS type VIIC were homozygous for a C→T transition that results in a premature termination codon, Q225X. Four of these five patients were homozygous at three downstream polymorphic sites. The sixth patient was homozygous for a different transition that results in a premature termination codon, W795X. In the dermatosparactic calf, the mutation is a 17-bp deletion that changes the reading frame of the message. These data provide direct evidence that EDS type VIIC and dermatosparaxis result from mutations in the pNPI gene.