References of "Heinen, Ernst"
     in
Bookmark and Share    
See detailPeculiar hydrophobic properties of the 67-78 fragment of α-synuclein are responsible for membrane destabilization and neurotoxicity
Crowet, Jean-Marc ULg; Lins, Laurence ULg; Dupiereux-Fettweis, Ingrid ULg et al

Poster (2006, December 18)

α-synuclein is a 140 residue protein linked to Parkinson’s disease. Intraneural inclusions called Lewy bodies and Lewy neurites are mainly composed of α-synuclein aggregated in amyloid fibrils. Few years ... [more ▼]

α-synuclein is a 140 residue protein linked to Parkinson’s disease. Intraneural inclusions called Lewy bodies and Lewy neurites are mainly composed of α-synuclein aggregated in amyloid fibrils. Few years ago, tilted peptides have been detected in two other amyloidogenic proteins : the amyloid β peptide involved in Alzheimer’s disease, and the PrP protein linked to Creuztfeldt-Jakob’s disease. Tilted peptides are short protein fragments that adopt an oblique orientation when inserted into biological membranes. Tilted peptides are able to destabilize membranes. In this study, we predicted by sequence analysis and molecular modelling that the 67-78 fragment of α-synuclein is a tilted peptide. Like most of them, the α-syn 67-78 peptide is able to induce lipid mixing and leakage of unilamellar liposomes. A mutant designed by molecular modelling to decrease the destabilizing properties of the peptide was shown to be significantly less fusogenic. The neuronal toxicity was studied using human neuroblastoma cells and we demonstrated that the α-syn 67-78 peptide induces neurotoxicity. In conclusion, we have identified a tilted peptide in α-synuclein which could be involved in the toxicity induced during amyloidogenesis of α-synuclein. [less ▲]

Detailed reference viewed: 10 (1 ULg)
Full Text
Peer Reviewed
See detailTRANSMISSION ET RÉSISTANCE DES PRIONS : LA PRATIQUE DE LA MÉDECINE DENTAIRE EN SERA T-ELLEAFFECTÉE ?
Elmoualij, Benaïssa ULg; Heinen, Ernst ULg; Zorzi, Willy ULg et al

in Journal de l'Ordre des Dentistes du Québec (2006), 43(9), 461-467

Detailed reference viewed: 17 (3 ULg)
Full Text
Peer Reviewed
See detailAdvances in immunoproteomics for serological characterization of microbial antigens
Falisse-Poirier, Nandini; Ruelle, Virginie ULg; Elmoualij, Benaïssa ULg et al

in Journal of Microbiological Methods (2006), 67(3), 593-596

We propose a multi-dimensional strategy, associating immunodetection to a protein fractionating two-dimensional liquid chromatography tool, for serological characterization of microbial antigens. The ... [more ▼]

We propose a multi-dimensional strategy, associating immunodetection to a protein fractionating two-dimensional liquid chromatography tool, for serological characterization of microbial antigens. The originality of such immunoproteomic approaches resides in their application in large-scale studies for rapid serotyping of micro-organisms, evaluation of immunomes and could be proposed in the development and monitoring of vaccines. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 24 (1 ULg)
Full Text
Peer Reviewed
See detailImmunoquantitative real-time PCR for detection and quantification of Staphylococcus aureus enterotoxin B in foods
Rajkovic, A.; Elmoualij, Benaïssa ULg; Uyttendaele, M. et al

in Applied and Environmental Microbiology (2006), 72(10), 6593-6599

A real-time immunoquantitative PCR (iqPCR) method for detection of Staphylococcus aureus enterotoxin B (SEB) was developed and evaluated using both pure cultures and foods. The assay consisted of ... [more ▼]

A real-time immunoquantitative PCR (iqPCR) method for detection of Staphylococcus aureus enterotoxin B (SEB) was developed and evaluated using both pure cultures and foods. The assay consisted of immunocapture of SEB and real-time PCR amplification of the DNA probe linked to the detection antibody. iqPCR was compared to an in-house enzyme-linked immunosorbent assay (ELISA) using the same couple of capture-detection antibodies and to commercial kits for detection of S. aureus enterotoxins (SE). The iqPCR was approximately 1,000 times more sensitive (< 10 pg ml(-1)) than the in-house ELISA and had a dynamic range of approximately 10 pg ml(-1) to approximately 30,000 pg ml(-1). iqPCR was not inhibited by any of the foods tested and was able to detect SEB present in these foods. No cross-reactivity with SE other than SEB was observed. Application of iqPCR for detection of SEB in cultures of S. aureus revealed the onset of SEB production after 4 It of incubation at 22, 37, and 42 degrees C, which was in the first half of the exponential growth phase. The total amounts of SEB produced by the two strains tested were larger at 42 degrees C than at 37 degrees C and were strain dependent. [less ▲]

Detailed reference viewed: 40 (2 ULg)
Full Text
Peer Reviewed
See detailDistribution of nerve fibres in bovine and human mucosal associated lymphoid tissues
Defaweux, Valérie ULg; Dorban, G.; Antoine, Nadine ULg et al

Poster (2006, October)

Prion cell tropism varies significantly among animal species, depending on both the agent strain and host-specific factors. For example, prions show high lymphotropism in scrapie infected sheep and vCJD ... [more ▼]

Prion cell tropism varies significantly among animal species, depending on both the agent strain and host-specific factors. For example, prions show high lymphotropism in scrapie infected sheep and vCJD, but little, if any, in sCJD or BSE. In particular, the BSE strain is associated with significant PrP-res accumulation in tonsils, spleen and appendix in humans, whereas it is largely confined to the nervous system in infected cattle. Therefore, at least in the case of BSE and vCJD, it appears that host properties can influence the accumulation of the infectious agent in lymphoid organs. Mature FDC play an important role in prion pathogenesis, since neuroinvasion following peripheral challenge is significantly impaired in their absence. The proximity between these FDC and sympathetic nerve endings is known to affect the speed of prion neuroinvasion. In this study, we analysed the mucosal innervation and the interface between nerve fibres and FDC in bovine and human tonsils and in ileal and jejunal bovine Peyer’s patches using a panel of antibodies observed by confocal microscopy. Since differences in the innervation of lymphoid organs depending on age have been reported, we analysed three categories of bovine ages (new born calves, calves less than 12 months old and bovines older than 24 months) and two categories of human ages (patients less than 5 years old and patients older than 25 years). In both species, hypothetical ways of innervation by-passing germinal centre could be postulated: nerve fibres are widely distributed in antigens/cells traffic area (the lamina propria, the interfollicular zone, the suprafollicular dome in Peyer’s patches and the lymphoepithelial area in tonsils). We pointed out that, only in ileal and jejunal Peyer’s patches and in tonsils of bovines older than 24 months, nerve fibres are observed to be in contact with FDC. In contrast, in human tonsils, no nerve fibres established contact with FDC, whatever the age. Thus, innervation of germinal centres can be said to be an age-dependent dynamic process in bovines and a weak innervation of the secondary lymphoid organs could thus be a rate-limiting step to neuroinvasion in humans. This variation could influence the way of neuroinvasion and thus, the differences of susceptibility of bovines and humans to the BSE agent. [less ▲]

Detailed reference viewed: 40 (11 ULg)
Peer Reviewed
See detailDendritic cells: potential actors in prion neuroinvasion.
Dorban, G.; Lallemand, C.; Defaweux, Valérie ULg et al

Poster (2006, September)

Detailed reference viewed: 13 (7 ULg)
Full Text
Peer Reviewed
See detailStudy on the toxic mechanism of prion protein peptide 106-126 in neuronal and non neuronal cells
Dupiereux-Fettweis, Ingrid ULg; Zorzi, Willy ULg; Rachidi, W. et al

in Journal of Neuroscience Research (2006), 84(3), 637-646

A synthetic peptide corresponding to the 106-126 amyloidogenic region of the cellular human prion protein (PrPc) is useful for in vitro study of prion-induced neuronal cell death. The aim of the present ... [more ▼]

A synthetic peptide corresponding to the 106-126 amyloidogenic region of the cellular human prion protein (PrPc) is useful for in vitro study of prion-induced neuronal cell death. The aim of the present work was to examine the implication of the cellular prion protein in the toxicity mechanism induced by PrP 106-126. The effect of PrP 106-126 was investigated both on human neuroblastoma SH-SY5Y cells and on SH-SY5Y over-expressing murine cellular prions (wtPrP). We show by metabolic assay tests and ATP assays that PrPc expression does not modulate the toxicity of the prion peptide. Moreover, we investigated the effect of this peptide on an established non neuronal model, rabbit kidney epithelial A74 cells that express a doxycycline-inducible murine PrPc gene. We show for the first time that the prion peptide 106-126 does not exert any toxic effect on this cell line in the presence or absence of doxycycline. Our results show that the PrP 106-126-induced cell alteration is independent of PrPc expression. Rather, it seems to act via an interaction with lipidic components of the plasma membrane as strengthened by our results showing the differential susceptibility of neuronal and non neuronal cell lines that significantly differ by their membrane fatty acid composition. (c) 2006 Wiley-Liss, Inc. [less ▲]

Detailed reference viewed: 36 (0 ULg)
Peer Reviewed
See detailLa tremblante du mouton influence-t-elle le système immunitaire lors d’une réponse vis-à-vis d’un antigène
Defaweux, Valérie ULg; Dorban, G.; Demonceau, C. et al

Conference (2005, November)

Detailed reference viewed: 27 (16 ULg)
See detailL'infection par les prions pathogènes modifie l'expression menbranaire de la PrPc par les cellules dendritiques
Dorban, G; Demonceau,C; Levavasseur, E et al

Poster (2005, October)

Detailed reference viewed: 23 (16 ULg)
Full Text
Peer Reviewed
See detailCharacterization of bovine and human cellular prion protein expressed in the central nervous system and in lymphoid organs.
Defaweux, Valérie ULg; Stramiello, Sara; Capellari, Sabina et al

Poster (2005, October)

Prion cell tropism varies significantly among animal species, depending on both the agent strain and host-specific factors. For example, prions show high lymphotropism in scrapie infected sheep and vCJD ... [more ▼]

Prion cell tropism varies significantly among animal species, depending on both the agent strain and host-specific factors. For example, prions show high lymphotropism in scrapie infected sheep and vCJD, but little, if any, in sCJD or BSE. In particular, the BSE strain is associate with significant PrP-res accumulation in tonsils, spleen and appendix in humans, whereas, it is largely confined to the nervous system in infected cattle. So, it appears that, at least in the case of BSE and vCJD, host properties can influence the accumulation of the infectious agent in lymphoid organs. Given that the normal cellular prion protein (PrPC), is sine qua non for PrP-res formation and the development of TSE, it appears reasonable to hypothesize that tissue-specific PrPC properties may represent one of the host factors influencing the cell tropism of the infectious agent in human or bovine. We applied a western blot analyses to compare the relative percentage of the di-, mono- and unglycosylated PrPC (the so called glycoform ratio) as well as the expression of truncated PrPC forms in tissues from the central nervous system and lymphoid structures (lymphoid follicles, lymphocytes and follicular dendritic cells) of both bovine and human. We found that PrPC glycoform ratio is significantly different between cerebellum and medulla in both bovine and human. Moreover, the expression of truncated forms of PrPC (i.e. 21 and 18 kDa PrPC) was also significantly heterogenous according to the brain region investigated. PrPC was highly glycosylated in spleen and lymphoid follicles isolated from bovine tonsils, mesenteric lymph nodes, ileal and jejunal Peyer’s patches. After deglycosylation, a novel PrPC truncated form with a relative molecular mass of about 25 kDa was detected in bovine lymphoid organs beside the typical 18 and 21 kDa forms. No difference in WB PrPC profile was seen in human lymphocytes extracted either from spleen or tonsil. Our results highlight variation in the profile expression of PrPC in peripheral and central tissues of bovine and human. Such differences may have an implication for PrPC function or may represent critical factors influencing the accumulation of the infectious agent in these areas. Supported by the EU contract QLG3-CT-2002-81030. [less ▲]

Detailed reference viewed: 25 (3 ULg)
Peer Reviewed
See detailImplication of Peyer’s patches dendritic cells in prion diseases.
Dorban, G.; Defaweux, Valérie ULg; Demonceau, C. et al

Poster (2005, June)

Detailed reference viewed: 8 (1 ULg)
Full Text
Peer Reviewed
See detailLymphotoxin-beta receptor-dependent genes in lymph node and follicular dendritic cell transcriptomes
Huber, Christoph; Thielen, Caroline ULg; Seeger, Harald et al

in Journal of Immunology (2005), 174(9), 5526-5536

Affinity-maturation and Ab class switches occur in lymphoid germinal centers (GCs), in which differentiation and maintenance depend on lymphotoxin (LT) signaling and include differentiation of follicular ... [more ▼]

Affinity-maturation and Ab class switches occur in lymphoid germinal centers (GCs), in which differentiation and maintenance depend on lymphotoxin (LT) signaling and include differentiation of follicular dendritic cells (FDCs). The events leading to FDC and GC maturation are poorly defined. Using several approaches of functional genomics, we enumerated transcripts affected in mice by suppressing LT beta receptor (LT beta R) signaling and/or overrepresented in FDC-enriched GC isolates. Protein expression analysis of 3 of 12 genes both enriched in FDCs and down-regulated by LT beta R signaling suppression validated them as FDC markers. Functional analysis of one of these three, clusterin, suggests a role as an FDC-derived trophic factor for GC B cells. Hence, the set of genes presented in this study includes markers emanating from LT beta R signaling and transcripts relevant to GC and FDC function. [less ▲]

Detailed reference viewed: 50 (7 ULg)
Peer Reviewed
See detailInvestigation of germinal centres in vivo and in vitro in the context of prion disease
Demonceau, C.; Defaweux, Valérie ULg; Flandroy, S. et al

Poster (2005, April)

Detailed reference viewed: 8 (2 ULg)