References of "Struman, Ingrid"
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See detailLymphangiogenesis and extracellular matrix remodeling
Erpicum, Charlotte ULg; Detry, Benoît ULg; Paupert, Jenny ULg et al

Conference (2013, January 28)

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See detailLaser-induced choroidal neovascularization model to study age-related macular degeneration in mice.
LAMBERT, Vincent ULg; Lecomte, Julie ULg; Hansen, Sylvain ULg et al

in Nature Protocols (2013), 8(11), 2197-2211

The mouse model of laser-induced choroidal neovascularization (CNV) has been used extensively in studies of the exudative form of age-related macular degeneration (AMD). This experimental in vivo model ... [more ▼]

The mouse model of laser-induced choroidal neovascularization (CNV) has been used extensively in studies of the exudative form of age-related macular degeneration (AMD). This experimental in vivo model relies on laser injury to perforate Bruch's membrane, resulting in subretinal blood vessel recruitment from the choroid. By recapitulating the main features of the exudative form of human AMD, this assay has served as the backbone for testing antiangiogenic therapies. This standardized protocol can be applied to transgenic mice and can include treatments with drugs, recombinant proteins, antibodies, adenoviruses and pre-microRNAs to aid in the search for new molecular regulators and the identification of novel targets for innovative treatments. This robust assay requires 7-14 d to complete, depending on the treatment applied and whether immunostaining is performed. This protocol includes details of how to induce CNV, including laser induction, lesion excision, processing and different approaches to quantify neoformed vasculature. [less ▲]

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See detailMicroRNA-146a is a therapeutic target and biomarker for peripartum cardiomyopathy.
Halkein, Julie ULg; Tabruyn, Sebastien P.; Ricke-Hoch, Melanie et al

in Journal of Clinical Investigation (2013), 123(5), 2143-54

Peripartum cardiomyopathy (PPCM) is a life-threatening pregnancy-associated cardiomyopathy in previously healthy women. Although PPCM is driven in part by the 16-kDa N-terminal prolactin fragment (16K PRL ... [more ▼]

Peripartum cardiomyopathy (PPCM) is a life-threatening pregnancy-associated cardiomyopathy in previously healthy women. Although PPCM is driven in part by the 16-kDa N-terminal prolactin fragment (16K PRL), the underlying molecular mechanisms are poorly understood. We found that 16K PRL induced microRNA-146a (miR-146a) expression in ECs, which attenuated angiogenesis through downregulation of NRAS. 16K PRL stimulated the release of miR-146a-loaded exosomes from ECs. The exosomes were absorbed by cardiomyocytes, increasing miR-146a levels, which resulted in a subsequent decrease in metabolic activity and decreased expression of Erbb4, Notch1, and Irak1. Mice with cardiomyocyte-restricted Stat3 knockout (CKO mice) exhibited a PPCM-like phenotype and displayed increased cardiac miR-146a expression with coincident downregulation of Erbb4, Nras, Notch1, and Irak1. Blocking miR-146a with locked nucleic acids or antago-miRs attenuated PPCM in CKO mice without interrupting full-length prolactin signaling, as indicated by normal nursing activities. Finally, miR-146a was elevated in the plasma and hearts of PPCM patients, but not in patients with dilated cardiomyopathy. These results demonstrate that miR-146a is a downstream-mediator of 16K PRL that could potentially serve as a biomarker and therapeutic target for PPCM. [less ▲]

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See detailMiR-205 is downregulated in hereditary hemorrhagic telangiectasia and impairs TGF-beta signaling pathways in endothelial cells.
Tabruyn, Sebastien P.; Hansen, Sylvain ULg; Ojeda-Fernandez, Maria-Luisa et al

in Angiogenesis (2013)

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disorder characterized by arteriovenous malformations and hemorrhages. This vascular disease results mainly from mutations in 2 genes ... [more ▼]

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disorder characterized by arteriovenous malformations and hemorrhages. This vascular disease results mainly from mutations in 2 genes involved in the TGF-beta pathway (ENG and ALK1) that are exclusively expressed by endothelial cells. The present study identified miR-27a and miR-205 as two circulating miRNAs differentially expressed in HHT patients. The plasma levels of miR-27a are elevated while those of miR-205 are reduced in both HHT1 and HHT2 patients compared to healthy controls. The role of miR-205 in endothelial cells was further investigated. Our data indicates that miR-205 expression displaces the TGF-beta balance towards the anti-angiogenic side by targeting Smad1 and Smad4. In line, overexpression of miR-205 in endothelial cells reduces proliferation, migration and tube formation while its inhibition shows opposite effects. This study not only suggests that detection of circulating miRNA (miR-27a and miR-205) could help for the screening of HHT patients but also provides a functional link between the deregulated expression of miR-205 and the HHT phenotype. [less ▲]

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See detailPhenotyping and outcome on contemporary management in a German cohort of patients with peripartum cardiomyopathy.
Haghikia, A.; Podewski, E.; Libhaber, E. et al

in Basic Research in Cardiology (2013), 108(4), 366

Peripartum cardiomyopathy (PPCM) is a life-threatening heart disease developing towards the end of pregnancy or in the months following delivery in previously healthy women in terms of cardiac disease ... [more ▼]

Peripartum cardiomyopathy (PPCM) is a life-threatening heart disease developing towards the end of pregnancy or in the months following delivery in previously healthy women in terms of cardiac disease. Enhanced oxidative stress and the subsequent cleavage of the nursing hormone Prolactin into an anti-angiogenic 16 kDa subfragment emerged as a potential causal factor of the disease. We established a prospective registry with confirmed PPCM present in 115 patients (mean baseline left ventricular ejection fraction, LVEF: 27 +/- 9 %). Follow-up data (6 +/- 3 months) showed LVEF improvement in 85 % and full recovery in 47 % while 15 % failed to recover with death in 2 % of patients. A positive family history of cardiomyopathy was present in 16.5 %. Pregnancy-associated hypertension was associated with a better outcome while a baseline LVEF </= 25 % was associated with a worse outcome. A high recovery rate (96 %) was observed in patients obtaining combination therapy with beta-blocker, angiotensin-converting enzyme (ACE) inhibitors/angiotensin-receptor-blockers (ARBs) and bromocriptine. Increased serum levels of Cathepsin D, the enzyme that generates 16 kDa Prolactin, miR-146a, a direct target of 16 kDa Prolactin, N-terminal-pro-brain-natriuretic peptide (NT-proBNP) and asymmetric dimethylarginine (ADMA) emerged as biomarkers for PPCM. In conclusion, low baseline LVEF is a predictor for poor outcome while pregnancy-induced hypertensive disorders are associated with a better outcome in this European PPCM cohort. The high recovery rate in this collective is associated with a treatment concept using beta-blockers, ACE inhibitors/ARBs and bromocriptine. Increased levels of Cathepsin D activity, miR-146a and ADMA in serum of PPCM patients support the pathophysiological role of 16 kDa Prolactin for PPCM and may be used as a specific diagnostic marker profile. [less ▲]

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See detailMatrix metalloproteinase-2 governs lymphatic vessel formation as an interstitial collagenase.
Detry, Benoît ULg; Erpicum, Charlotte ULg; Paupert, Jenny ULg et al

in Blood (2012), 119(21), 5048-56

Lymphatic dysfunctions are associated with several human diseases, including lymphedema and metastatic spread of cancer. Although it is well recognized that lymphatic capillaries attach directly to ... [more ▼]

Lymphatic dysfunctions are associated with several human diseases, including lymphedema and metastatic spread of cancer. Although it is well recognized that lymphatic capillaries attach directly to interstitial matrix mainly composed of fibrillar type I collagen, the interactions occurring between lymphatics and their surrounding matrix have been overlooked. In this study, we demonstrate how matrix metalloproteinase (MMP)–2 drives lymphatic morphogenesis through Mmp2-gene ablation in mice, mmp2 knockdown in zebrafish and in 3D-culture systems, and through MMP2 inhibition. In all models used in vivo (3 murine models and thoracic duct development in zebrafish) and in vitro (lymphatic ring and spheroid assays), MMP2 blockage or down-regulation leads to reduced lymphangiogenesis or altered vessel branching. Our data show that lymphatic endothelial cell (LEC) migration through collagen fibers is affected by physical matrix constraints (matrix composition, density and cross-linking). Transmission electron microscopy (TEM) and confocal reflection microscopy using DQ-collagen highlight the contribution of MMP2 to mesenchymal-like migration of LEC associated with collagen fiber remodeling. Our findings provide new mechanistic insight into how LEC negotiate an interstitial type I collagen barrier and reveal an unexpected MMP2-driven collagenolytic pathway for lymphatic vessel formation and morphogenesis. [less ▲]

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See detailMicroRNA-146a is a causative factor and a specific biomarker for peripartum cardiomyopathy
Halkein, Julie ULg; Tabruyn, Sébastien ULg; Haghikia, Arash et al

Poster (2012, April)

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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 detail16-kDa prolactin and bromocriptine in postpartum cardiomyopathy.
Hilfiker-Kleiner, Denise; Struman, Ingrid ULg; Hoch, Melanie et al

in Current Heart Failure Reports (2012), 9(3), 174-82

Peripartum cardiomyopathy (PPCM) is a potentially life-threatening heart disease emerging toward the end of pregnancy or in the first postpartal months in previously healthy women. Recent data suggest a ... [more ▼]

Peripartum cardiomyopathy (PPCM) is a potentially life-threatening heart disease emerging toward the end of pregnancy or in the first postpartal months in previously healthy women. Recent data suggest a central role of unbalanced peri-/postpartum oxidative stress that triggers the proteolytic cleavage of the nursing hormone prolactin (PRL) into a potent antiangiogenic, proapoptotic, and proinflammatory 16-kDa PRL fragment. This notion is supported by the observation that inhibition of PRL secretion by bromocriptine, a dopamine D2-receptor agonist, prevented the onset of disease in an animal model of PPCM and by first clinical experiences where bromocriptine seem to exert positive effects with respect to prevention or treatment of PPCM patients. Here, we highlight the current state of knowledge on diagnosis of PPCM, provide insights into the biology and pathophysiology of 16-kDa PRL and bromocriptine, and outline potential consequences for the clinical management and treatment options for PPCM patients. [less ▲]

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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 detailDre-miR-2188 Targets Nrp2a and Mediates Proper Intersegmental Vessel Development in Zebrafish Embryos.
Soares, Ana R.; Reverendo, Marisa; Pereira, Patricia M. et al

in PLoS ONE (2012), 7(6), 39417

BACKGROUND: MicroRNAs (miRNAs) are a class of small RNAs that are implicated in the control of eukaryotic gene expression by binding to the 3'UTR of target mRNAs. Several algorithms have been developed ... [more ▼]

BACKGROUND: MicroRNAs (miRNAs) are a class of small RNAs that are implicated in the control of eukaryotic gene expression by binding to the 3'UTR of target mRNAs. Several algorithms have been developed for miRNA target prediction however, experimental validation is still essential for the correct identification of miRNA targets. We have recently predicted that Neuropilin2a (Nrp2a), a vascular endothelial growth factor receptor which is essential for normal developmental angiogenesis in zebrafish, is a dre-miR-2188 target. METHODOLOGY: Here we show that dre-miR-2188 targets the 3'-untranslated region (3'UTR) of Nrp2a mRNA and is implicated in proper intersegmental vessel development in vivo. Over expression of miR-2188 in zebrafish embryos down regulates Nrp2a expression and results in intersegmental vessel disruption, while its silencing increases Nrp2a expression and intersegmental vessel sprouting. An in vivo GFP sensor assay based on a fusion between the GFP coding region and the Nrp2a 3'UTR confirms that miR-2188 binds to the 3'UTR of Nrp2a and inhibits protein translation. CONCLUSIONS: We demonstrate that miR-2188 targets Nrp2a and affects intersegmental vessel development in zebrafish embryos. [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 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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