References of "Kesteloot, Frédéric"
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See detailEffects of compression on human subchondral osteoblast metabolism
Kesteloot, Frédéric ULg; Gabay, Odile; Msika, Philippe et al

Poster (2009, May 24)

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 ... [more ▼]

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. [less ▲]

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See detailFollow-up of COLL2-1, COLL2-1NO2 and myeloperoxydase in dogs after transection of the cruciate ligament of the knee
Kesteloot, Frédéric ULg; Pelletier, Jean-Pierre; Martel-Pelletier, Johanne et al

Poster (2009, May 23)

Purpose: To determine the profile of Coll2-1, Coll2-1NO2 and myeloperoxydase (MPO) serum concentrations in experimental knee OA induced in the dog by transection of the anterior cruciate ligament. Methods ... [more ▼]

Purpose: To determine the profile of Coll2-1, Coll2-1NO2 and myeloperoxydase (MPO) serum concentrations in experimental knee OA induced in the dog by transection of the anterior cruciate ligament. Methods: Surgical transection of the ACL of the right knee was performed on 16 adult crossbred dogs. The dogs were sacrificed 8 weeks after the surgical procedure. Coll2-1, Coll2-1NO2 and MPO were measured by specific immunoassays in 16 dogs at baseline and every 2 weeks during the 8 weeks. The results were expressed as median (range). Results: Immunostainings with D3 and D37, the antiserum recognizing Coll2-1 and Coll2-1NO2, respectively, labelled extracellular matrix in the superficial layer of fibrillated cartilage. After the transection of the ACL, the concentration of 3 biomarkers increased significantly (Friedman test: p<0.001). The concentrations of Coll2-1 and MPO were significantly increased at week 2 compared to baseline [Coll2-1 baseline: 281.57 (131.02-384.67) nM vs Coll2-1 week 2: 345.52 (181.15-589.25) nM (p<0.01) and MPO baseline: 5.16 (<0.4-14.7) ng/ml vs MPO week 2: 14.54 (3.28-31.50) ng/ml (p<0.001)] and remained stable until week 8 [Coll2-1 week 8:318.89 (117.95-492.28) nM and MPO week 8: 11.55 (2.87-42.94) ng/ml]. The Coll2-1NO2 concentration increased significantly at weeks 6 and 8 compared to baseline [Coll2-1NO2 baseline: 0.54 (0.29-1.48) nM vs Coll2-1NO2 week 6: 0.64 (0.40-1.9) nM (p<0.001) vs week 8: 0.61 (0.37-1.79) nM]. Conclusions: These findings suggest that Coll2-1 is a relevant marker for the detection of early structural changes in OA dogs. Interestingly, MPO and Coll2-1NO2 are increased in OA dogs indicating that an oxidative stress occurs in this OA model. [less ▲]

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See detailNewly identified biologically active and proteolysis-resistant VEGF-A isoform VEGF111 is induced by genotoxic agents
Mineur, Pierre ULg; Colige, Alain ULg; Deroanne, Christophe ULg et al

in Journal of Cell Biology (2007), 179(6), 1261-1273

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 ... [more ▼]

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. [less ▲]

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See detailADAM metallopeptidase with thrombospondin type 1 motif 2 inactivation reduces the extent and stability of carbon tetrachloride-induced hepatic fibrosis in mice
Kesteloot, Frédéric ULg; Desmoulière, Alexis; Leclercq, Isabelle et al

in Hepatology (Baltimore, Md.) (2007), 46(5), 1620-1631

ADAMTS2 belongs to the "ADAM metallopeptidase with thrombospondin type I motif" (ADAMTS) family. Its primary function is to process collagen type I, II, III, and V precursors into mature molecules by ... [more ▼]

ADAMTS2 belongs to the "ADAM metallopeptidase with thrombospondin type I motif" (ADAMTS) family. Its primary function is to process collagen type I, II, III, and V precursors into mature molecules by excising the aminopropeptide. This process allows the correct assembly of collagen molecules into fibrils and fibers, which confers to connective tissues their architectural structure and mechanical resistance. To evaluate the impact of ADAMTS2 on the pathological accumulation of extracellular matrix proteins, mainly type I and III collagens, we evaluated carbon tetrachloride-induced liver fibrosis in ADAMTS2-deficient (TS2(-/-)) and wild-type (WT) mice. A single carbon tetrachloride injection caused a similar acute liver injury in deficient and WT mice. A chronic treatment induced collagen deposition in fibrous septa that were made of thinner and irregular fibers in TS2(-/-) mice. The rate of collagen deposition was slower in TS2(-/-) mice, and at an equivalent degree of fibrosis, the resorption of fibrous septa was slightly faster. Most of the genes involved in the development and reversion of the fibrosis were similarly regulated in TS2(-/-) and NW mice. Conclusion: These data indicate that the extent of fibrosis is reduced in TS2(-/-) mice in comparison with their WT littermates. Inhibiting the maturation of fibrillar collagens may be a beneficial therapeutic approach to interfering with the development of fibrotic lesions. [less ▲]

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See detailRegulation of procollagen amino-propeptide processing during mouse embryogenesis by specialization of homologous ADAMTS proteases: insights on collagen biosynthesis and dermatosparaxis
Le Goff, Carine; Somerville, Robert PT; Kesteloot, Frédéric ULg et al

in Development (2006), 133(8), 1587-1596

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 ... [more ▼]

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. [less ▲]

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See detailDomains and maturation processes that regulate the activity of ADAMTS-2, a metalloproteinase cleaving the aminopropeptide of fibrillar procollagens types I-III and V
Colige, Alain ULg; Ruggiero, Florence; Vandenberghe, Isabel et al

in Journal of Biological Chemistry (2005), 280(41), 34397-34408

Processing of fibrillar collagens is required to generate collagen monomers able to self-assemble into elongated and cylindrical collagen fibrils. ADAMTS-2 belongs to the "A disintegrin and ... [more ▼]

Processing of fibrillar collagens is required to generate collagen monomers able to self-assemble into elongated and cylindrical collagen fibrils. ADAMTS-2 belongs to the "A disintegrin and metalloproteinase with thrombospondin type 1 motifs" (ADAMTS) family. It is responsible for most of the processing of the aminopropeptide of type I procollagen in the skin, and it also cleaves type II and type III procollagens. ADAMTS are complex secreted enzymes that are implicated in various physiological and pathological processes. Despite accumulating evidence indicating that their activity is regulated by ancillary domains, additional information is required for a better understanding of the specific function of each domain. We have generated 17 different recombinant forms of bovine ADAMTS-2 and characterized their processing, activity, and cleavage specificity. The results indicated the following: (i) activation of the ADAMTS-2 zymogen involves several cleavages, by proprotein convertases and C-terminal processing, and generates at least seven distinct processed forms; (ii) the C-terminal domain negatively regulates enzyme activity, whereas two thrombospondin type 1 repeats are enhancer regulators; (iii) the 104-kDa form displays the highest aminoprocollagen peptidase activity on procollagen type I; (iv) ADAMTS-2 processes the aminopropeptide of alpha1 type V procollagen homotrimer at the end of the variable domain; and (v) the cleaved sequence (PA) is different from the previously described sites ((P/A)Q) for ADAMTS-2, redefining its cleavage specificity. This finding and the existence of multiple processed forms of ADAMTS-2 strongly suggest that ADAMTS-2 may be involved in function(s) other than processing of fibrillar procollagen types I-III. [less ▲]

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See detailADAMTS-2, a metalloproteinase containing a disintegrin domain and thrombospondin type I repeats, a new regulator of angiogenesis
Dubail, Johanne ULg; Kesteloot, Frédéric ULg; Motte, Patrick ULg et al

in Journal of Vascular Research (2005), 42(Suppl. 2), 76

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 able to strongly repress angiogenesis. The ... [more ▼]

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 able to strongly repress angiogenesis. The primary function of ADAMTS-2 is to process procollagen type I, II, III and V into mature molecules by excising the amino-propeptide. We further hypothesized that it could modulate angiogenesis through its TSP1 repeats. Recombinant ADAMTS-2 induced morphological changes in HUVEC and HMEC cultured on gelatin, collagen and fibronectin. It also significantly reduced their proliferation, attachment and spreading. Similar effects were observed when using inactive ADAMTS-2 mutated at the Zn++-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 more rapidly disrupted in presence of ADAMTS-2 than in control conditions. Immunostaining with monoclonal antibodies against ADAMTS-2 indicate that it is tightly immobilized at the endothelial cell surface by an heparin-sensitive binding. With the aim to identify mechanism(s)leading to the modulation of angiogenesis by ADAMTS-2, we investigated various signalling pathways critical for EC. Phosphorylation status of FAK was not altered by ADAMTS-2 while a downregulation of phosphorylation of p42/44 MAPK was observed. Our data suggest that ADAMTS-2 reduces angiogenesis by regulating endothelial cell adhesion and proliferation, and by alteration of the stability of the capillary-like structures. These effects do not seem to be mediated by an integrin-dependent signaling pathway. Choroidal neovascularization induced in TS2+/+ or TS2-/- mice by LASER burns was used as in vivo model. Several genes involved in the healing and angiogenesis processes (fibrillar collagens, VEGF, TGF, CTGF, …) were not differently regulated in TS2+/+ and TS2-/- mice 5 days after the LASER impact. Wound capillaries visualized by confocal microscopy after FITC-conjugated dextran injection, were significantly increased (p<0,05) in TS2-/- mice suggesting an increased angiogenic response in the KO animals. The results obtained in in vivo and in vitro models indicate that ADAMTS-2 is involved in the control of angiogenesis. Additional investigations are being performed to determine which domain(s) of the molecule is (are) antiangiogenic and to identify the mechanism(s) underlying this regulatory function. [less ▲]

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See detailEffect of ADAMTS-2, a metalloproteinase containing a disintegrin domain and thrombospondin type I repeats, during angiogenesis in vitro and in vivo
Dubail, Johanne ULg; Kesteloot, Frédéric ULg; Motte, Patrick ULg et al

in Angiogenesis (2004), 7(2), 172

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 ... [more ▼]

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. [less ▲]

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See detailEvaluation of the function of ADAMTS-2, a metalloproteinase containing a disintegrin domain and thrombospondin type I repeats, during angiogenesis in vitro and in vivo
Kesteloot, Frédéric ULg; Lapière, Charles M; Colige, Alain ULg et al

in Acta Clinica Belgica (2004), 59(2), 120

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 ... [more ▼]

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. [less ▲]

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