Search PubMed⌕ Search

Biomedical subjects

C Munaut

Publications and source records attributed to C Munaut.

At least 19 recordsLinked to original sources
PubMed2006

Expression of a disintegrin and metalloprotease (ADAM and ADAMTS) enzymes in human non-small-cell lung carcinomas (NSCLC).

A Disintegrin and Metalloprotease (ADAM) are transmembrane proteases displaying multiple functions. ADAM with ThromboSpondin-like motifs (ADAMTS) are secreted proteases characterised by thrombospondin (TS) motifs in their C-terminal domain. The aim of this work was to evaluate the expression pattern of ADAMs and ADAMTS in non small cell lung carcinomas (NSCLC) and to investigate the possible correlation between their expression and cancer progression. Reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot and immunohistochemical analyses were performed on NSCLC samples and corresponding nondiseased tissue fragments. Among the ADAMs evaluated (ADAM-8, -9, -10, -12, -15, -17, ADAMTS-1, TS-2 and TS-12), a modulation of ADAM-12 and ADAMTS-1 mRNA expression was observed. Amounts of ADAM-12 mRNA transcripts were increased in tumour tissues as compared to the corresponding controls. In sharp contrast, ADAMTS-1 mRNA levels were significantly lower in tumour tissues when compared to corresponding nondiseased lung. These results were corroborated at the protein level by Western blot and immunohistochemistry. A positive correlation was observed between the mRNA levels of ADAM-12 and those of two vascular endothelial growth factor (VEGF)-A isoforms (VEGF-A(165) and VEGF-A(121)). Taken together, these results providing evidence for an overexpression of ADAM-12 and a lower expression of ADAMTS-1 in non-small-cell lung cancer suggest that these proteases play different functions in cancer progression.

ADAM Proteins↗
PubMed2005

Smooth muscle cell matrix metalloproteinases in idiopathic pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) results from persistent vasoconstriction, smooth muscle growth and extracellular matrix (ECM) remodelling of pulmonary arteries (PAs). Matrix metalloproteinases (MMPs) are matrix-degrading enzymes involved in ECM turnover, and in smooth muscle cell (SMC) and endothelial cell migration and proliferation. MMP expression and activity are increased in experimental PAH. Therefore, this study investigated whether similar changes occur in idiopathic PAH (IPAH; formerly known as primary pulmonary hypertension). Both in situ and in vitro studies were performed on PAs from patients undergoing lung transplantation for IPAH and from patients treated by lobectomy for localised lung cancer, who served as controls. In IPAH, MMP-tissue inhibitor of metalloproteinase (TIMP) imbalance was found in cultured PA-SMCs, with increased TIMP-1 and decreased MMP-3. MMP-2 activity was markedly elevated as a result of increases in both total MMP-2 and proportion of active MMP-2. In situ zymography and immunolocalisation showed that MMP-2 was associated with SMCs and elastic fibres, and also confirmed the MMP-3-TIMP-1 imbalance. In conclusion, the findings of this study were consistent with a role for the matrix metalloproteinase-tissue inhibitor of metalloproteinase system in pulmonary vascular remodelling in idiopathic pulmonary arterial hypertension. The matrix metalloproteinase-tissue inhibitor of metalloproteinase imbalance may lead to matrix accumulation, and increased matrix metalloproteinase-2 activity may contribute to smooth muscle cell migration and proliferation. Whether these abnormalities are potential therapeutic targets deserves further investigation.

Cells, Cultured↗
PubMed2004

Human chorionic gonadotropin and growth factors at the embryonic-endometrial interface control leukemia inhibitory factor (LIF) and interleukin 6 (IL-6) secretion by human endometrial epithelium.

BACKGROUND: The elucidation of the molecular mechanisms by which the embryo contributes to its implantation is an area of extensive research. The main objective of this study was to investigate the pattern of leukemia inhibitory factor (LIF) and interleukin-6 (IL-6) secretion by human endometrial epithelium, and their regulation by human chorionic gonadotropin (hCG) and other growth factors present at the embryonic-endometrial interface. METHODS: Endometrial epithelial cells (EEC) were isolated from biopsies collected at both proliferative and secretory phases of fertile women. RESULTS: HCG (1-50 IU/ml) increased LIF secretion by EEC cultures derived from follicular phase (up to 285+/-75%) or from secretory phase (up to 212+/-16%). In contrast, hCG reduced IL-6 secretion by EEC in both phases. The hCG/LH receptor gene was transcribed by EEC as evidenced by RT-PCR. Insulin-like growth factors 1 and 2 increased LIF secretion by EEC. Transforming growth factor beta1 stimulated LIF and reduced IL-6 secretion. CONCLUSIONS: Through hCG, the blastocyst may be involved in the control of its implantation (via an increase of proimplantatory LIF) and tolerance (via an inhibition of proinflammatory IL-6). Other growth factors present at the embryonic-endometrial interface are also involved in the control of LIF and IL-6 endometrial secretion.

Adolescent↗
PubMed2003

Evidence of a limited contribution of feto-maternal interactions to trophoblast differentiation along the invasive pathway.

Trophoblast differentiation is a key event in human placental development. During extravillous trophoblast (EVT) differentiation, stem cells from the anchoring villi detach from their basement membrane and proliferate to form aggregates called trophoblast cell columns (TCCs). They subsequently invade the decidua and differentiate into interstitial and endovascular trophoblasts. The influence of the decidua on EVT differentiation is controversial. We therefore compared the pattern of trophoblast differentiation marker expression in viable intrauterine and tubal pregnancies, as decidual cell markers (prolactin [PRL] and insulin-like growth factor binding Protein-1 [IGFBP1]) were only expressed in endometrial implantation sites. Extravillous trophoblast differentiation in anchoring villi from uterine and ectopic pregnancies exhibited a comparable phenotypical switch: alpha6 integrin subunit, E-cadherin, EGF receptor, Ki 67 and connexin 40 were localized in the proximal part of the TCC, while alpha5beta1 and alpha1 integrins, c-erb B2, hPL and HLA-G were expressed by invasive cytotrophoblasts. The cyclin-dependent kinase inhibitors p16 and p57 were mainly detected in invasive cytotrophoblasts some distance from the columns. However, the TCC was markedly longer in tubal pregnancy than in intrauterine pregnancy. These findings suggest that the decidua is not necessary to trigger EVT invasion, but that it is likely to limit the extent of the TCC and to accelerate the onset of EVT migration.

Biomarkers↗
PubMed2002

Murine 5T multiple myeloma cells induce angiogenesis in vitro and in vivo.

Multiple myeloma is a B cell malignancy. Recently, it has been demonstrated that bone marrow samples of patients with multiple myeloma display an enhanced angiogenesis. The mechanisms involved seem to be multiple and complex. We here demonstrate that the murine 5T multiple myeloma models are able to induce angiogenesis in vitro by using a rat aortic ring assay and in vivo by determining the microvessel density. The rat aortic rings cultured in 5T multiple myeloma conditioned medium exhibit a higher number of longer and more branched microvessels than the rings cultured in control medium. In bone marrow samples from 5T multiple myeloma diseased mice, a statistically significant increase of the microvessel density was observed when compared to bone marrow samples from age-matched controls. The angiogenic phenotype of both 5T multiple myeloma cells could be related, at least in part, to their capacity to produce vascular endothelial growth factor. These data clearly demonstrate that the 5T multiple myeloma models are good models to study angiogenesis in multiple myeloma and will allow to unravel the mechanisms of neovascularisation, as well as to test new putative inhibitors of angiogenesis.

Animals↗
PubMed2002

Macrophage migration inhibitory factor (MIF) expression in human glioblastomas correlates with vascular endothelial growth factor (VEGF) expression.

Macrophage migration inhibitory factor (MIF) is a peptide released upon hypothalamo-pituitary stimulation that acts as a potent endogenous antagonist of the glucocorticoid inhibition of acute inflammatory response and subsequent antigen-specific response. MIF also sustains tumour growth as it promotes angiogenesis, overcomes p53-mediated cell growth arrest and inhibits tumour-specific immune responses. Using quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry, we studied MIF expression in 35 human glioblastomas and two normal brains. We compared these results with the expression of vascular endothelial growth factor (VEGF), the most potent angiogenic factor in glioblastomas. We detected MIF in normal cortical neurons and glial cells. All glioblastomas were positive for MIF mRNA with expression levels similar to or higher than those of normal brain. MIF immunoreactivity was seen mainly in tumour cells and less frequently in hyperplastic endothelial cells. The expressions of MIF and VEGF mRNA were strongly correlated (P < 0.0001). Our results demonstrate the expression of MIF in human glioblastomas, and indicate a close relationship with VEGF expression. This is of particular interest given the potential modulation of MIF by glucocorticosteroids.

Adult↗
PubMed2002

MT1-MMP expression promotes tumor growth and angiogenesis through an up-regulation of vascular endothelial growth factor expression.

Membrane type 1 metalloprotease (MT1-MMP) is a transmembrane metalloprotease that plays a major role in the extracellular matrix remodeling, directly by degrading several of its components and indirectly by activating pro-MMP2. We investigated the effects of MT1-MMP overexpression on in vitro and in vivo properties of human breast adenocarcinoma MCF7 cells, which do not express MT1-MMP or MMP-2. MT1-MMP and MMP-2 cDNAs were either transfected alone or cotransfected. All clones overexpressing MT1-MMP 1) were able to activate endogenous or exogenous pro-MMP-2, 2) displayed an enhanced in vitro invasiveness through matrigel-coated filters independent of MMP-2 transfection, 3) induced the rapid development of highly vascularized tumors when injected subcutaneously in nude mice, and 4) promoted blood vessels sprouting in the rat aortic ring assay. These effects were observed in all clones overexpressing MT1-MMP regardless of MMP-2 expression levels, suggesting that the production of MMP-2 by tumor cells themselves does not play a critical role in these events. The angiogenic phenotype of MT1-MMP-producing cells was associated with an up-regulation of VEGF expression. These results emphasize the importance of MT1-MMP during tumor angiogenesis and open new opportunities for the development of anti-angiogenic strategies combining inhibitors of MT1-MMP and VEGF antagonists.

Animals↗
PubMed2001

Distinct pathways in the over-expression of matrix metalloproteinases in human fibroblasts by relaxation of mechanical tension.

The aim of the work was to analyze, on a comparative basis, the signaling pathways operating in the regulation of a panel of matrix metalloproteinases (MMP) expressed by human dermal fibroblasts submitted to mechanical stress relaxation by cytochalasin D (CD) and in a retracting collagen gel (RCG). The mRNA steady-state level of MMPs was measured by a quantitative RT-PCR procedure using a synthetic RNA as internal standard. In monolayer, most MMPs were barely detected, except MMP-2. Disruption of the actin stress fibers by CD induced a moderate increase of MMP-2 mRNA and a much larger stimulation of MMP-3, -9, -13 and -14 mRNAs. In RCG, a significant up-regulation of these MMPs was also observed although to a lower extent than in CD-treated monolayers. Among the investigated MMPs, the MMP-8 and -11 were not reproducibly detected. MMP-2 was processed to its active form both by CD and in RCG. The CD-induced up-regulation of gene expression was largely repressed by blocking protein synthesis by cycloheximide for all the MMPs, by inhibiting the tyrosine-kinases of the src family by herbimycin A for all MMPs, except MMP-2, and by inhibiting the TPA-inducible PKC isoforms by bisindoyl maleimide for all MMPs, except MMP-14. The up-regulation induced by stress relaxation in RCG was protein synthesis-dependent for MMP-2 and MMP-13, tyrosine kinases-dependent for MMP-3 and MMP-13, as previously described for MMP-1. Inhibiting TPA-inducible PKC did not affect any MMP in RCG except MMP-13, which was strongly induced. The processing of MMP-2 was tyrosine kinases-dependent but PKC-independent. Inhibitors of the ERK1,2 and p38 MAP kinases pathways diversely affected the MMPs expression. Inhibiting the Rho-kinase activity by Y-27632 was inactive. These results point to the potent regulation operated by the status of the cytoskeleton on the cell phenotype, and to distinct regulatory pathways involved in the control of different MMPs expression.

Animals↗
PubMed2001

Matrix metalloproteinases and TIMP-1 production by peripheral blood granulocytes from COPD patients and asthmatics.

Both asthmatic and COPD patients were found to have increased amounts of granulocytes and matrix metalloproteinase-9 (MMP-9) in their sputum. The present study was conducted to investigate whether the elevated amounts of MMP-9 and TIMP-1 found in such patients' airways may be linked to an enhanced secretion by granulocytes. Blood granulocytes from asthmatics (n = 10), COPD patients (n = 11), and healthy controls (n = 11) were isolated and cultured under basal conditions or after stimulation by phorbol 12-myristate 13-acetate (PMA) or N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP). MMP-9 activity was detected by zymography while MMP-8 and TIMP-1 levels were measured by ELISA. In zymography, pro- and activated forms of MMP-9 were present in each group (healthy subjects, asthmatics, and COPD patients). Spontaneous release was not different between the three groups. Stimulation by fMLP and PMA increased to a similar extent the release of MMP-9 by granulocytes in all the three groups. TIMP-1 levels were also increased after stimulation by PMA and fMLP only in healthy subjects and COPD patients. MMP-8 levels were barely detectable. We conclude that circulating granulocytes from COPD patients and asthmatics do not display an abnormal secretion of MMP-9, and that granulocytes from asthmatics have an impaired ability to release TIMP-1 upon stimulation.

Adult↗
PubMed2001

Down-Regulation of MT1-MMP expression by the alpha3 chain of type IV collagen inhibits bronchial tumor cell line invasion.

The basement membrane (BM) is the first barrier encountered by tumor cells when they become invasive. Moreover, some invasive tumor clusters are surrounded by a remnant or neosynthetized BM material. We have previously reported the presence of a particular alpha chain of type IV collagen, the alpha3(IV) chain, in bronchopulmonary carcinomas. This chain was not detected in the normal bronchial epithelium, but was found around some invasive tumor cluster BM. In the present study, we examined the effects of the alpha3(IV) chain on the invasive properties of bronchial tumor cell lines, with special emphasis on their expression of matrix metalloproteinase-2 (MMP-2) and its activator, membrane type 1-matrix metalloproteinase (MT1-MMP), which is largely involved in tumor progression. Two epithelial bronchial cell lines (16HBE14o- and BZR), showing different invasive abilities, were evaluated. Using the Boyden chamber invasion assay, we demonstrated that the alpha3(IV) chain inhibits the invasive properties of BZR cells and modifies their morphology by inducing an epithelial cell shape. In the presence of the recombinant NC1 domain of the alpha3(IV) chain, the expression of MMP-2 and tissue inhibitor of metalloproteinase-2 (TIMP-2) was not modified in either cell line. The NC1 alpha3(IV) domain did not modulate the MT1-MMP expression of noninvasive 16HBE14o- cells, whereas a 50% decrease of MT1-MMP mRNA was observed in invasive BZR cells. Accordingly, Western blot analyses showed a disappearance of the 45-kd MT1-MMP form when BZR cells were treated with the recombinant NC1 alpha3(IV) domain. These findings suggest that the alpha3 chain of type IV collagen may play a role in tumor invasion, at least by decreasing the expression and synthesis of MT1-MMP.

Bronchi↗
PubMed2001

Influence of plasminogen activator inhibitor type 1 on choroidal neovascularization.

High levels of the plasminogen activators, but also their inhibitor, plasminogen activator inhibitor 1 (PAI-1), have been documented in neovascularization of severe ocular pathologies such as diabetic retinopathy or age-related macular degeneration (AMD). AMD is the primary cause of irreversible photoreceptors loss, and current therapies are limited. PAI-1 has recently been shown to be essential for tumoral angiogenesis. We report here that deficient PAI-1 expression in mice prevented the development of subretinal choroidal angiogenesis induced by laser photocoagulation. When systemic and local PAI-1 expression was achieved by intravenous injection of a replication-defective adenoviral vector expressing human PAI-1 cDNA, the wild-type pattern of choroidal angiogenesis was restored. These observations demonstrate the proangiogenic activity of PAI-1 not only in tumoral models, but also in choroidal experimental neovascularization sharing similarities with human AMD. They identify therefore PAI-1 as a potential target for therapeutic ocular anti-angiogenic strategies.

Adenoviridae↗
PubMed2001

Presence of oestrogen receptor type beta in human retina.

BACKGROUND/AIMS: Recent studies have demonstrated the existence of two oestrogen receptor subtypes alpha (ORalpha) and beta (ORbeta) with significant differences of expression among organs. Since important pathologies of human eye could be linked to hormonal status, the expression of ORbeta in ocular posterior segment was sought. METHODS: Immunohistochemical localisation of ORbeta and ORalpha protein and detection of OR mRNAs by reverse transcription-polymerase chain reaction (RT-PCR) were performed in macular and extramacular regions of the retina and in the choroid on male and female donors eyes. RESULTS: ORbeta protein was localised in the ganglion cell layer and in the choroid. At the transcriptional level, mRNA for ORbeta and for ORalpha were both present. Local differences in the expression level were observed, however, suggesting the possibility of variation in the ratio of ORalpha v ORbeta. CONCLUSIONS: The coexistence of two oestrogen receptor subtypes in the human ocular posterior segment raises acute questions about their potential physiological role, but offers a perspective for preferential targeting of a specific receptor subtype.

Aged↗
PubMed2001

Contribution of MT1-MMP and of human laminin-5 gamma2 chain degradation to mammary epithelial cell migration.

Membrane-type matrix metalloproteinase 1 (MT1-MMP) is a membrane-anchored matrix metalloproteinase (MMP) that is frequently associated with processes involving tissue remodelling and cell migration. We have examined MT1-MMP expression and subcellular distribution as a function of MCF10A mammary epithelial cell migration using an in vitro outgrowth migration assay. Stronger expression of MT1-MMP was observed at the mRNA and at the protein level in cells at the periphery of the outgrowth. As shown by videomicroscopy, these cells were involved in an orientated cell migration, in contrast to stationary cells distant from the periphery. Furthermore, MT1-MMP was mainly distributed in lamellipodia of migratory cells, as well as at their basal surface in contact with the substrate. Laminin-5 (Ln-5), a recently described substrate for MT1-MMP, was deposited preferentially in the matrix by migratory cells. Fragments of the gamma2 subunit of Ln-5 were also identified in migratory cultures of MCF10A cells, attesting to its proteolytic degradation. These fragments corresponded in size to those we observed after incubation of purified human Ln-5 with the recombinant catalytic domain of human MT1-MMP. We also show that anti-Ln5 blocking antibodies, MMP inhibitors (BB94 and TIMP-2) and MT1-MMP antisense oligonucleotides significantly decreased MCF10A cell migration. Taken together, these observations demonstrate that MT1-MMP is spatially and temporally regulated during MCF10A cell migration, and suggest that MT1-MMP-mediated pericellular proteolysis of Ln-5 gamma2 chain could contribute to this process.

Blotting, Western↗
PubMed2000

Membrane type 1 matrix metalloproteinase-associated degradation of tissue inhibitor of metalloproteinase 2 in human tumor cell lines.

Tissue inhibitor of metalloproteinase 2 (TIMP-2) is required for the membrane type 1 matrix metalloproteinase (MT1-MMP)-dependent activation of pro-MMP-2 on the cell surface. MT1-MMP-bound TIMP-2 has been shown to function as a receptor for secreted pro-MMP-2, resulting in the formation of a trimolecular complex. In the presence of uncomplexed active MT1-MMP, the prodomain of cell surface-associated MMP-2 is cleaved, and activated MMP-2 is released. However, the behavior of MT1-MMP-bound TIMP-2 during MMP-2 activation is currently unknown. In this study, (125)I-labeled recombinant TIMP-2 ((125)I-rTIMP-2) was used to investigate the fate of TIMP-2 during pro-MMP-2 activation by HT1080 and transfected A2058 cells. HT1080 and A2058 cells transfected with MT1-MMP cDNA (but not vector-transfected A2058 cells) were able to bind (125)I-rTIMP-2, to activate pro-MMP-2, and to process MT1-MMP into an inactive 43-kDa form. Under these conditions, (125)I-rTIMP-2 bound to the cell surface was rapidly internalized and degraded in intracellular organelles through a bafilomycin A(1)-sensitive mechanism, and (125)I-bearing low molecular mass fragment(s) were released in the culture medium. These different processes were inhibited by hydroxamic acid-based synthetic MMP inhibitors and rTIMP-2, but not by rTIMP-1 or cysteine, serine, or aspartic proteinase inhibitors. These results support the concept that the MT1-MMP-dependent internalization and degradation of TIMP-2 by some tumor cells might be involved in the regulation of pericellular proteolysis.

Enzyme Activation↗
PubMed2000

MMP-2- and MMP-9-linked gelatinolytic activity in the sputum from patients with asthma and chronic obstructive pulmonary disease.

BACKGROUND: The course of asthma and chronic obstructive pulmonary disease (COPD) is associated with bronchial morphological changes. Metalloproteinases are thought to play a role in these structural changes. METHODS: We studied the gelatinolytic activity present in the induced sputum from 20 patients with asthma, 20 with COPD and 19 healthy controls. The assessment of gelatinolytic activity was performed by quantitative zymography, and gelatinolytic species were identified by Western blot analysis. Tissue inhibitor of metalloproteinase-1 (TIMP-1) was detected by reverse zymography and ELISA. RESULTS: From zymography, we found significantly higher gelatinolytic activity linked to pro-matrix metalloproteinase-9 (pro-MMP-9) in the sputum from asthmatics (p < 0.0001) and COPD patients (p < 0.0001) compared to the control group. Furthermore, the activated form of MMP-9 (85 kD) was found in the sputum from 60% of asthmatics and 85% of COPD patients, but was absent in that of control subjects (p < 0.0001). Importantly, although less frequently detectable than pro-MMP-9, pro- MMP-2 (72 kD) was found more frequently in asthmatics (50%) than in control subjects (5%) (p < 0. 005). We also described two unusual gelatinolytic species of 45 and 120 kD and showed that they derived from MMP-9 according to their ability to bind gelatin and anti-MMP-9 antibody. Levels of TIMP-1 were higher in asthmatics (p < 0.05) and COPD patients (p < 0.05) than in controls. CONCLUSION: Asthmatics and COPD patients display an increased gelatinolytic activity linked to MMP-2 and MMP-9 and higher levels of TIMP-1 in their sputum.

Adult↗
PubMed2000

[Bronchial morphologic modification in asthma].

Asthma is an inflammatory disease of the airways clinically characterised by recurrent bronchial obstructions at least partially reversible. Recent epidemiologic data suggest that asthmatics have an increased rate of decrease of their expiratory volumes during life. This irreversible lung function impairment is associated with fundamental structural changes of the bronchial wall in terms of conjunctive tissue and smooth muscle composition. We describe these changes and explore the different mechanisms proposed to explain these structural modifications. We also review their consequences in terms of bronchial physiology and their potential influence on bronchial hyperresponsiveness.

Asthma↗
PubMed1999

Murine matrix metalloproteinase 9 gene. 5'-upstream region contains cis-acting elements for expression in osteoclasts and migrating keratinocytes in transgenic mice.

Knowledge about the regulation of cell lineage-specific expression of extracellular matrix metalloproteinases is limited. In the present work, the murine matrix metalloproteinase 9 (MMP-9) gene was shown to contain 13 exons, and the 2.8-kilobase pair upstream region was found to contain several common promoter elements including a TATA box-like motif, three GC boxes, four AP-1-like binding sites, an AP-2 site, and three PEA3 consensus sequences that may be important for basic activity of the gene. In order to identify cell-specific regulatory elements, constructs containing varying lengths of the upstream region in front of a LacZ reporter gene were made and studied for expression in transgenic mice generated by microinjection into fertilized oocytes. Analyses of the mice revealed that the presence of sequences between -2722 and -7745 allowed for expression in osteoclasts and migrating keratinocytes, i. e. cells that have been shown to normally express the enzyme in vivo. The results represent the first in vivo demonstration of the location of cell-specific control elements in a matrix metalloproteinase gene and show that element(s) regulating most cell-specific activities of 92-kDa type collagenase are located in the -2722 to -7745 base pair region.

Amino Acid Sequence↗