References of "Martial, Joseph"
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See detailMiR-146a an angiostatic miRNA elevated in peripartum cardiomyopathy
Halkein, Julie ULg; Tabruyn, Sébastien ULg; Haghikia, Arash et al

Poster (2012, January)

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See detailA panel of biological tests reveals developmental effects of pharmaceutical pollutants on late stage zebrafish embryos.
Pruvot, Benoist ULg; Quiroz O' Donova, Yobhana ULg; Voncken, Audrey ULg et al

in Reproductive Toxicology (2012)

Standard toxicological assays using the zebrafish model system evaluate lethality and teratogenicity upon exposure during the first two days after fertilization. We tested the biological effects of ... [more ▼]

Standard toxicological assays using the zebrafish model system evaluate lethality and teratogenicity upon exposure during the first two days after fertilization. We tested the biological effects of several widely used drugs on zebrafish by acute treatment for 24hours starting at late embryonic stages, between 48 and 72hours post-fertilization. For 4 out of 6 compounds, we observed a higher sensitivity of late stage zebrafish embryos for general toxicity (lethality) compared to younger embryos. Morphological defects such as edema, body curvature, delayed growth, decreased heart rate and locomotion were observed for each of the compounds tested, often at sublethal concentrations. Gene expression studies on a set of four selected genes revealed a specific regulatory pattern for the different compounds tested. Our results allow us to compare various toxicological endpoints and may contribute to the design of a rational high throughput approach using the zebrafish model. [less ▲]

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See detailRUNX3, EGR1 AND SOX9B FORM A REGULATORY CASCADE REQUIRED TO MODULATE BMP-SIGNALING DURING CRANIAL CARTILAGE DEVELOPMENT IN ZEBRAFISH.
Dalcq, Julia ULg; Pasque, Vincent; Ghaye, Aurélie ULg et al

in PLoS ONE (2012), in press

The cartilaginous elements forming the pharyngeal arches of the zebrafish derive from cranial neural crest cells. Their proper differentiation and patterning are regulated by reciprocal interactions ... [more ▼]

The cartilaginous elements forming the pharyngeal arches of the zebrafish derive from cranial neural crest cells. Their proper differentiation and patterning are regulated by reciprocal interactions between neural crest cells and surrounding endodermal, ectodermal and mesodermal tissues. In this study, we show that the endodermal factors Runx3 and Sox9b form a regulatory cascade with Egr1 resulting in transcriptional repression of the fsta gene, encoding a BMP antagonist, in pharyngeal endoderm. Using a transgenic line expressing a dominant negative BMP receptor or a specific BMP inhibitor (dorsomorphin), we show that BMP signaling is indeed required around 30 hpf in the neural crest cells to allow cell differentiation and proper pharyngeal cartilage formation. Runx3, Egr1, Sox9b and BMP signaling are required for expression of runx2b, one of the key regulator of cranial cartilage maturation and bone formation. Finally, we show that egr1 depletion leads to increased expression of fsta and inhibition of BMP signaling in the pharyngeal region. In conclusion, we show that the successive induction of the transcription factors Runx3, Egr1 and Sox9b constitutes a regulatory cascade that controls expression of Follistatin A in pharyngeal endoderm, the latter modulating BMP signaling in developing cranial cartilage in zebrafish. [less ▲]

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See detailScaphandre La science rencontre l'art: L'art
Haubruge, Eric ULg; Bay, Daniel ULg; Semal, Jean et al

in Haubruge, Eric; Bay, Daniel; Semal, Jean (Eds.) Scaphandre La science rencontre l'art (2012)

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See detailMicroRNA-146a, a downstream effector of 16kDa prolactin, impairs the endothelium-cardiomyocyte cross-talk in peripartum cardiomyopathy
Struman, Ingrid ULg; Halkein, Julie ULg; Tabruyn, Sébastien ULg et al

in FASEB meeting:the Growth Hormone/Prolactin Family in Biology and Disease. (2012)

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See detailThe HMG-Box Transcription Factor Sox4b Is Required for Pituitary Expression of gata2a and Specification of Thyrotrope and Gonadotrope Cells in Zebrafish.
Quiroz O'Donova, Yobhana ULg; Lopez, Marie-Josée ULg; Mavropoulos, A et al

in Molecular Endocrinology (2012), 26(6), 1014-1027

The pituitary is a complex gland comprising different cell types each secreting specific hormones. The extensive network of signaling molecules and transcription factors required for determination and ... [more ▼]

The pituitary is a complex gland comprising different cell types each secreting specific hormones. The extensive network of signaling molecules and transcription factors required for determination and terminal differentiation of specific cell types is still not fully understood. The SRY-like HMG-box (SOX) transcription factor Sox4 plays important roles in many developmental processes and has two homologs in zebrafish, Sox4a and Sox4b. We show that the sox4b gene is expressed in the pituitary anlagen starting at 24 h after fertilization (hpf) and later in the entire head region including the pituitary. At 48 hpf, sox4b mRNA colocalizes with that for TSH (tshbeta), glycoprotein subunit alpha (gsualpha), and the Zn finger transcription factor Gata2a. Loss of Sox4b function, using morpholino knockdown or expression of a dominant-negative Sox4 mutant, leads to a drastic decrease in tshbeta and gsualpha expression and reduced levels of gh, whereas other anterior pituitary gland markers including prl, slbeta, pomc, and lim3 are not affected. Sox4b is also required for expression of gata2a in the pituitary. Knockdown of gata2a leads to decreased tshbeta and gsualpha expression at 48 hpf, similar to sox4b morphants. Injection of gata2a mRNA into sox4b morphants rescued tshbeta and gsualpha expression in thyrotrope cells. Finally, sox4b or gata2a knockdown causes a significant decrease of gonadotropin expression (lhbeta and fshbeta) at 4 d after fertilization. In summary, our results indicate that Sox4b is expressed in zebrafish during pituitary development and plays a crucial role in the differentiation of thyrotrope and gonadotrope cells through induction of gata2a expression in the developing pituitary. [less ▲]

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See detailFast Homozygosity Mapping and Identification of a Zebrafish ENU-Induced Mutation by Whole-Genome Sequencing.
Voz, Marianne ULg; Coppieters, Wouter ULg; Manfroid, Isabelle ULg et al

in PLoS ONE (2012), 7(4), 34671

Forward genetics using zebrafish is a powerful tool for studying vertebrate development through large-scale mutagenesis. Nonetheless, the identification of the molecular lesion is still laborious and ... [more ▼]

Forward genetics using zebrafish is a powerful tool for studying vertebrate development through large-scale mutagenesis. Nonetheless, the identification of the molecular lesion is still laborious and involves time-consuming genetic mapping. Here, we show that high-throughput sequencing of the whole zebrafish genome can directly locate the interval carrying the causative mutation and at the same time pinpoint the molecular lesion. The feasibility of this approach was validated by sequencing the m1045 mutant line that displays a severe hypoplasia of the exocrine pancreas. We generated 13 Gb of sequence, equivalent to an eightfold genomic coverage, from a pool of 50 mutant embryos obtained from a map-cross between the AB mutant carrier and the WIK polymorphic strain. The chromosomal region carrying the causal mutation was localized based on its unique property to display high levels of homozygosity among sequence reads as it derives exclusively from the initial AB mutated allele. We developed an algorithm identifying such a region by calculating a homozygosity score along all chromosomes. This highlighted an 8-Mb window on chromosome 5 with a score close to 1 in the m1045 mutants. The sequence analysis of all genes within this interval revealed a nonsense mutation in the snapc4 gene. Knockdown experiments confirmed the assertion that snapc4 is the gene whose mutation leads to exocrine pancreas hypoplasia. In conclusion, this study constitutes a proof-of-concept that whole-genome sequencing is a fast and effective alternative to the classical positional cloning strategies in zebrafish. [less ▲]

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See detailA peptide mimicking the C-terminal part of the reactive center loop induces the transition to the latent form of Plasminogen Activator Inhibitor Type-1
D'Amico, Salvino ULg; Martial, Joseph ULg; Struman, Ingrid ULg

in FEBS Letters (2012), 586

Plasminogen Activator Inhibitor-1 (PAI-1) is the primary inhibitor of plasminogen activators (uPA and tPA) and thus plays a central role in fibrinolysis. The spontaneous insertion of its Reactive Centre ... [more ▼]

Plasminogen Activator Inhibitor-1 (PAI-1) is the primary inhibitor of plasminogen activators (uPA and tPA) and thus plays a central role in fibrinolysis. The spontaneous insertion of its Reactive Centre Loop (RCL) into beta-sheet A is responsible for its irreversible conversion into the inactive latent form. In this study, we used two peptides mimicking residues P14-P9 and P8-P3 of the RCL so as to understand this dynamic process. We show that both peptides inhibit the formation of PAI 1/uPA and PAI-1/tPA complexes via two different mechanisms. Targeting the N-terminal part of the loop induces the cleavage of PAI-1 by the proteases uPA/tPA while targeting its C-terminal part greatly favors the irreversible formation of latent PAI-1. [less ▲]

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See detailZebrafish sox9b is crucial for hepatopancreatic duct development and pancreatic endocrine cell regeneration
Manfroid, Isabelle ULg; Ghaye, Aurélie ULg; Naye, François et al

in Developmental Biology (2012)

Recent zebrafish studies have shown that the late appearing pancreatic endocrine cells derive from pancreatic ducts but the regulatory factors involved are still largely unknown. Here, we show that the ... [more ▼]

Recent zebrafish studies have shown that the late appearing pancreatic endocrine cells derive from pancreatic ducts but the regulatory factors involved are still largely unknown. Here, we show that the zebrafish sox9b gene is expressed in pancreatic ducts where it labels the pancreatic Notchresponsive cells previously shown to be progenitors. Inactivation of sox9b disturbs duct formation and impairs regeneration of beta cells from these ducts in larvae. sox9b expression in the midtrunk endoderm appears at the junction of the hepatic and ventral pancreatic buds and, by the end of embryogenesis, labels the hepatopancreatic ductal system as well as the intrapancreatic and intrahepatic ducts. Ductal morphogenesis and differentiation are specifically disrupted in sox9b mutants, with the dysmorphic hepatopancreatic ducts containing misdifferentiated hepatocyte-like and pancreatic-like cells. We also show that maintenance of sox9b expression in the extrapancreatic and intrapancreatic ducts requires FGF and Notch activity, respectively, both pathways known to prevent excessive endocrine differentiation in these ducts. Furthermore, beta cell recovery after specific ablation is severely compromised in sox9b mutant larvae. Our data position sox9b as a key player in the generation of secondary endocrine cells deriving from pancreatic ducts in zebrafish. [less ▲]

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See detailThe Antiangiogenic 16K Prolactin Impairs Functional Tumor Neovascularization by Inhibiting Vessel Maturation
Nguyen, Ngoc-Quynh-Nhu ULg; Castermans, Karolien; Berndt, Sarah et al

in PLoS ONE (2011), 6(11), 27318-27318

Background: Angiogenesis, the formation of new blood vessels from existing vasculature, plays an essential role in tumor growth, invasion, and metastasis. 16K hPRL, the antiangiogenic 16-kDa N-terminal ... [more ▼]

Background: Angiogenesis, the formation of new blood vessels from existing vasculature, plays an essential role in tumor growth, invasion, and metastasis. 16K hPRL, the antiangiogenic 16-kDa N-terminal fragment of human prolactin was shown to prevent tumor growth and metastasis by modifying tumor vessel morphology. Methodology/Principal Findings: Here we investigated the effect of 16K hPRL on tumor vessel maturation and on the related signaling pathways. We show that 16K hPRL treatment leads, in a murine B16-F10 tumor model, to a dysfunctional tumor vasculature with reduced pericyte coverage, and disruption of the PDGF-B/PDGFR-B, Ang/Tie2, and Delta/Notch pathways. In an aortic ring assay, 16K hPRL impairs endothelial cell and pericyte outgrowth from the vascular ring. In addition, 16K hPRL prevents pericyte migration to endothelial cells. This event was independent of a direct inhibitory effect of 16K hPRL on pericyte viability, proliferation, or migration. In endothelial cell-pericyte cocultures, we found 16K hPRL to disturb Notch signaling. Conclusions/Significance: Taken together, our data show that 16K hPRL impairs functional tumor neovascularization by inhibiting vessel maturation and for the first time that an endogenous antiangiogenic agent disturbs Notch signaling. These findings provide new insights into the mechanisms of 16K hPRL action and highlight its potential for use in anticancer therapy. [less ▲]

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See detailStainless steel with robust anibacterial activiy based on a versatile and bio-inspired strategy
Faure, Emilie ULg; Lecomte, Philippe ULg; Vreuls, Christelle ULg et al

Conference (2011, September 01)

The synthesis of a poly(methacrylamide) bearing 3,4-dihydroxyphenylalanine inspired from the chemical composition of mussel adhesives will be presented. This homopolymer is designed to insure a multilayer ... [more ▼]

The synthesis of a poly(methacrylamide) bearing 3,4-dihydroxyphenylalanine inspired from the chemical composition of mussel adhesives will be presented. This homopolymer is designed to insure a multilayer film growth by covalent coupling during the layer-by-layer building with a homopolymer containing amino groups. The film cross-linking is initiated by adequately controlling both the redox state of the polymer and the pH of the solutions. This cross-linking is evidenced by solid-state 13C NMR with the occurrence of a typical signal of imine, traducing the Schiff base formation during film growth. The same coupling reaction is implemented for grafting an antibacterial peptide, Nisin, on a stainless steel substrate. Antibacterial activity against Bacillus subtilis is preserved even after long immersion time, as the result of the peptide covalent anchoring on the surface. All the processing steps, including the synthesis of the polymers and the peptide grafting, are performed in aqueous solutions under mild conditions. [less ▲]

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See detailGenetically engineered polypeptides as a new tool for inorganic nano-particles separation in water based media
Vreuls, Christelle ULg; Genin, Alexis ULg; Zocchi, Germaine ULg et al

in Journal of Materials Chemistry (2011), 21

The present paper relates a method for the separation of an insoluble inorganic powder out of a mixture of several insoluble powders with different chemical compositions, using genetically engineered ... [more ▼]

The present paper relates a method for the separation of an insoluble inorganic powder out of a mixture of several insoluble powders with different chemical compositions, using genetically engineered inorganic binding peptides (GEPI). GEPI are small peptides that recognize and specifically bind an inorganic solid material. This GEPI is anchored to magnetic beads for easy recovery of the powder of interest from the mixture. [less ▲]

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See detailSustainable and bio-inspired chemistry for robust antibacterial activity of stainless steel
Faure, Emilie ULg; Lecomte, Philippe ULg; Lenoir, Sandrine et al

in Journal of Materials Chemistry (2011), 21(22), 7901-7904

We report on the original synthesis of a poly(methacrylamide) bearing (oxidized) 3,4-dihydroxyphenylalanine specially designed to (i) insure film growth by covalent coupling, (ii) covalently bind an ... [more ▼]

We report on the original synthesis of a poly(methacrylamide) bearing (oxidized) 3,4-dihydroxyphenylalanine specially designed to (i) insure film growth by covalent coupling, (ii) covalently bind an antibacterial peptide and (iii) contribute to the film cross-linking that is essential for the durability of the properties. [less ▲]

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See detailThe antiangiogenic 16K prolactin disturbs functional tumor neovascularization by affecting vessel maturation
Nguyen, Ngoc-Quynh-Nhu ULg; Castermans, Karolien; Berndt, Sarah et al

Poster (2011, May)

16K hPRL, the antiangiogenic 16-kDa N-terminal fragment of human prolactin was shown to prevent tumor growth and metastasis by modifying tumor vessel morphology. Here we investigated the effect of 16K ... [more ▼]

16K hPRL, the antiangiogenic 16-kDa N-terminal fragment of human prolactin was shown to prevent tumor growth and metastasis by modifying tumor vessel morphology. Here we investigated the effect of 16K hPRL on tumor vessel maturation and on the related signaling pathways. We show that 16K hPRL treatment leads, in a murine B16-F10 tumor model, to a dysfunctional tumor vasculature with reduced pericyte coverage, and disruption of the PDGF-B/PDGFR-B, Ang/Tie2, and Delta/Notch pathways. In an aortic ring assay, 16K hPRL impairs endothelial cell and pericyte outgrowth from the vascular ring. In addition, 16K hPRL prevents pericyte migration to endothelial cells. This event was independent of a direct inhibitory effect of 16K hPRL on pericyte viability, proliferation, or migration. In endothelial cell-pericyte cocultures, we found 16K hPRL to disturb Notch signaling, this being the first time such an effect is observed with an endogenous antiangiogenic agent. These findings provide new insights into the mechanisms of 16K hPRL action and highlight its potential for use in anticancer therapy. [less ▲]

Detailed reference viewed: 34 (5 ULg)