Regulation of procollagen amino-propeptide processing during mouse embryogenesis by specialization of homologous ADAMTS proteases: insights on collagen biosynthesis and dermatosparaxis

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. brillar 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. broblasts, 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

Newly identified biologically active and proteolysis-resistant VEGF-A isoform VEGF111 is induced by genotoxic agents

Ultraviolet B and genotoxic drugs induce the expression of a vascular endothelial growth factor A (VEGF-A) splice variant (VEGF111) encoded by exons 1–4 and 8 in many cultured cells. Although not detected in a series of normal human and mouse tissue, VEGF111 expression is induced in MCF-7 xenografts in nude mice upon treatment by camptothecin. The skipping of exons that contain proteolytic cleavage sites and extracellular matrix–binding domains makes VEGF111 diffusible and resistant to proteolysis. Recombinant VEGF111 activates VEGF receptor 2 (VEGF-R2) and extracellularly regulated kinase 1/2 in human umbilical vascular endothelial cells and porcine aortic endothelial cells expressing VEGF-R2. The mitogenic and chemotactic activity and VEGF111's ability to promote vascular network formation during embyonic stem cell differentiation are similar to those of VEGF121 and 165. Tumors in nude mice formed by HEK293 cells expressing VEGF111 develop a more widespread network of numerous small vessels in the peritumoral tissue than those expressing other isoforms. Its potent angiogenic activity and remarkable resistance to proteolysis makes VEGF111 a potential adverse factor during chemotherapy but a beneficial therapeutic tool for ischemic diseases

CULTURE DE CELLULES DANS BILLES D'HYDROGEL DE CHITOSANE-ALGINATE

publication date: 2011-09-01; filing date: 2011-02-11The present invention relates to a method of producing a hydrogel matrix comprising cartilage-forming cells wherein alginate, chitosan and cartilage- forming cells are mixed and subsequently polymerised into beads

Cell cultivation in chitosan alginate hydrogel beads

publication date: 2011-08-31; filing date: 2010-02-25The present invention relates to a method of producing a hydrogel matrix comprising cartilage-forming cells wherein alginate, chitosan and cartilage-forming cells are mixed and subsequently polymerised into beads

Evaluation of the function of ADAMTS-2, a metalloproteinase containing a disintegrin domain and thrombospondin type I repeats, during angiogenesis in vitro and in vivo

Angiogenesis is required for development, growth, tissue remodeling, and wound healing. Pathologies such as diabetic retinopathy, rheumatoid arthritis and cancer would benefit from therapies controlling and reducing angiogenesis. Enzymes of the ADAMTS family are closely related to MMPs and ADAMs. They contain however some specific features, such as a variable number of domains known as “ThromboSpondin type I repeat” (TSPI). ADAMTS-1 and -8 are 20-fold more anti-angiogenic than angiostatin and endostatin, two potent inhibitors of angiogenesis. The primary function of ADAMTS-2 is the maturation of collagen type I and II molecules by excising the amino-propeptide. In addition, ADAMTS-2 could also modulate angiogenesis, as it contains the same sequences than those responsible for the anti-angiogenic activity of ADAMTS-1 and -8. This hypothesis was investigated in vitro in different experimental models such as cell proliferation and formation of capillary structures by human endothelial cells. An ex vivo angiogenesis model was also used. It consists in mice or rat aorta pieces embedded in a collagen gel in order to allow the growth of capillaries from the vascular endothelium. As compared to control mice (TS2+/+), angiogenesis was slightly increased, in absence of ADAMTS-2, from aortas of ADAMTS-2 KO mice (TS2-/-). Using rat aortas, addition of recombinant ADAMTS-2 reduced the formation of capillary structure, also confirming the anti-angiogenic activity of ADAMTS-2. Finally, an in vivo model of angiogenesis was also used. Biocompatible sponges (Ivalon) were implanted under the skin of TS2+/+ or TS2-/- mice in order to evaluate the formation of capillaries in the granulation tissue invading the sponge. In absence of ADAMTS-2, angiogenesis and granulation tissue formation were both reduced. Additional investigations are being performed in order to identify the underlying mechanism(s) inducing these modifications

Effect of ADAMTS-2, a metalloproteinase containing a disintegrin domain and thrombospondin type I repeats, during angiogenesis in vitro and in vivo

Formation of new blood vessels (angiogenesis) is a key step during the development of various pathologies, including cancer. Enzymes of the ADAMTS family are closely related to MMPs and ADAMs. They further contain specific domains, such as the ‘‘Thrombospondin type I’’ (TSP1) repeats, that are able to strongly repress angiogenesis, as described for thrombospondin-1 and -2, and for ADAMTS-1 and -8. The primary function of ADAMTS-2 is to process collagen type I, II and III precursors into mature molecules by excising the aminopropeptide. We further hypothesized that it could modulate angiogenesis through its TSP1 repeats. This hypothesis was investigated using different in vitro experimental models of angiogenesis. Recombinant ADAMTS-2 induced morphological changes in human umbilical vein endothelial cells (HUVEC) and human microvessel endothelial cells (HMEC), and significantly reduced their proliferation, attachment and spreading. Similar effects were observed when using inactive ADAMTS-2 mutated at the Zn2+-binding catalytic site. ADAMTS-2 did not alter the initial steps of formation of capillary-like structures by HUVEC in vitro. However, these structures appeared much less stable and were more rapidly disrupted in presence of ADAMTS-2 than in control conditions. ADAMTS-2 was also tested in an ex vivo angiogenesis model using aortic rings from rats and mice, wild type or KO for ADAMTS-2. Outgrowth of capillaries was slightly increased from aortas of ADAMTS-2 KO mice (TS2-/-) as compared to aortas from control animals (TS2+/+), while addition of full size recombinant ADAMTS-2 reduced the formation of capillary structures from rat aortas, suggesting its anti-angiogenic activity. Choroidal neovascularization induced in TS2+/+ or TS2-/- mice by LASER burns was used as in vivo model to confirm the in vitro and ex vivo results. Several genes involved in the healing and angiogenesis processes (fibrillar collagens, VEGF, TGF-beta and CTGF) were not differently regulated in TS2+/+ and TS2-/- mice at 5 days

A better future without the North Metro

Is there still time to stop the North Metro project? For the authors of this BSI Position Paper, the public inquiry for the digging of a new tunnel is the opportunity to do so. Priorities have changed (telework, energy crisis, etc). This project poses a serious threat to regional finances and, consequently, to the other policies which the Region must pursue. Moreover, the expected environmental gain turns out to be negligible and the anticipated improvement in mobility, unsatisfactory

Un avenir meilleur sans le Métro Nord

Est-il encore temps d’arrêter le projet Métro Nord ? Pour les auteurs de ce BSI Position Paper, l’enquête publique pour le creusement d’un nouveau tunnel nous en offre l’occasion. Les priorités ont changé (télétravail, crise énergétique…). Or, ce projet constitue une menace grave pour les finances régionales et, partant, pour les autres politiques que la Région doit mener. Alors que le gain environnemental escompté se révèle négligeable et l’amélioration attendue de la mobilité peu satisfaisante

Een betere toekomst zonder Metro Noord

Kan het metro Noord project nog gestopt worden? Voor de auteurs van deze BSI Position Paper biedt het openbaar onderzoek naar aanleiding van de geplande graafwerken voor een nieuwe tunnel inderdaad deze kans. De prioriteiten zijn ondertussen veranderd (telewerk, energiecrisis,…) en het project in kwestie vormt een grote bedreiging voor de gewestelijke begroting en de andere beleidskeuzes die het Gewest dient te maken; en dit terwijl de verwachte winst voor het leefmilieu te verwaarlozen is en de verbetering van de mobiliteit weinig bevredigend

Effects of compression on human subchondral osteoblast metabolism

Introduction. Recent data showed that subchondral bone plays an important role in osteoarthritis (OA). Metabolic and morphologic modifications in this tissue contribute to the degradation of the overlaying cartilage. It was suggested that abnormal mechanical pressure exerted onto the articulation was responsible to these changes. Here, we evaluated the effects of compression on osteoblasts from subchondral bone. Method. Osteoblasts were isolated from sclerotic (SC) or non-sclerotic (NSC) areas of human OA subchondral bone. After 28 days, osteoblasts were surrounded by their matrix. This osteoblasts-containing membrane was then placed onto a Biopress Flexercell plate and submitted to a 4h 1.67 MPa compression (1 Hz). Expression of IL-6, IL-8, COX-2, VEGF, IGF-1, OPG and RANKL was evaluated by RT-PCR. IL-6, IL-8 and PGE2 were quantified by ELISA. Results. Basal IL-6, VEGF, COX-2, IGF-1 and RANKL mRNA levels were significantly increased in SC osteoblasts as compared to NSC. By contrast, SC osteoblasts expressed less OPG than those from NSC areas. Compressions induced the expression of genes coding for IL-6, IL-8, COX-2, IGF-1, VEGF and RANKL but decreased the expression of OPG in NSC osteoblasts (p<0.01). Interestingly, compressed NSC osteoblasts expressed similar levels of these genes than SC osteoblasts. Conclusions. We show that our model of compression can induce in NSC osteoblasts a phenotype similar to this observed in sclerotic areas. Moreover, SC osteoblasts are less sensitive to mechanical stimuli than NSC osteoblasts. These results clarify the role of compression in the pathogenesis of subchondral bone sclerosis and allow new perspectives of research in this field