Gupta S.,De Duve Institute |
Michels P.A.M.,De Duve Institute |
Michels P.A.M.,Catholic University of Louvain
Molecular and Biochemical Parasitology | Year: 2011
Steroids such as dehydroepiandrosterone (DHEA) and epiandrosterone (EA) exert multiple effects in mammals including the inhibition of glucose-6-phosphate dehydrogenase (G6PDH). Initially, the inhibition was considered specific for the mammalian enzyme. The beneficial effect of these steroids on infections by protists and nematodes was attributed to stimulation of the immune system. However, we showed previously that DHEA and EA also inhibit Trypanosoma brucei and T. cruzi G6PDH, with low micromolar K i values, but not the enzyme from Leishmania species, and kill in vitro cultured trypanosomes. We report here that, contrary to wild-type trypanosomes, mutant bloodstream-form T. brucei cells expressing L. mexicana G6PDH are not susceptible to the steroids, proving that G6PDH is the in situ target. Moreover, bromo-derivatives of the steroids show 50-100 fold lower K i values for the enzyme and display an increased potency to kill the parasites. Therefore, the compounds offer promise for use in development of parasite-selective drugs. © 2011 Elsevier B.V. All rights reserved.
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: HEALTH-2007-1.2-2 | Award Amount: 4.70M | Year: 2008
The CARS EXPLORER seeks to demonstrate the concept of innovative light-based contrasting technologies for functional in situ imaging in life science and biomedical research. Our ultimate goal is to develop an endoscope based on non-linear optics (NLO) and laser pulse phase shaping. Non linear laser pulse interactions with living tissues provide unique possibilities, such as an absence of sample preparation, direct multiparametric visualization with molecular specificity and cellular resolution, and deep sample penetration. Nevertheless, the effective transfer of NLO to biomedical applications faces major technological challenges related to the delivery of ultra-short laser pulses, the weakness of the signal produced in biological samples and the difficulty in interpreting generated contrasts. Therefore, the CARS EXPLORER interdisciplinary consortium includes partners with expertise ranging from optical physics to the clinic. The work plan is split into 5 RTD workpackages: three are intended to overcome specific technological problems with (1) the development of dedicated methodology using phase shaping for NLO imaging of deep biological tissues, (2) the development of specific photonic crystal fibre optics for the excitation, delivery and collection of NLO signals, and (3) the extraction of relevant information from NLO signals generated in biological tissues. The two other workpackages will determine the assets and constraints in NLO imaging through appropriate experimental biological models. These models will also assess each technological improvement made on the microscope and endoscope prototypes. Last, to bring the concept to the diagnostic level, we will explore the molecular and morphological NLO signatures associated with tumor development in skin cancer. In addition to the challenge of developing pulse shaped NLO-based endoscope technology, this project will have strategic and economic impact by providing a non-invasive functional exploration method.
Agency: European Commission | Branch: FP7 | Program: MC-ITN | Phase: FP7-PEOPLE-ITN-2008 | Award Amount: 3.72M | Year: 2009
Aims: provide a cutting edge research training programme encompassing complementary approaches to the investigation of liver and pancreatic development and disease. Provide early stage researchers with a balanced mix of experience and skills in academic and industry based research. Give early stage researchers a set of transferrable skills which will improve their employment and career prospects. Objectives: 1) To provide a broad multi-disciplinary approach to liver and pancreatic development and disease which will ensure a solid foundation in research technology and methods. 2) To offer a number of multi-centre and cross-sector projects. 3) To organize regular meetings which will provide task-specific and complementary training in skills essential for career development. Implementation: 1) involvement of highly successful research leaders and groups (with expertise in different disciplines including systems biology and bioinformatics, developmental biology, genomics, genetics and epigenetics, cell biology, engineering and drug development) in design and running of this programme will ensure the cutting edge research methodology and multidisciplinary approach to training. 2) Each research project will involve minimum two partners. 3) Partners will alternate in organizing network meetings which will include laboratory courses, single-topic conferences and network workshops. 4) The experienced researchers recruited to the network will spend more time in the industrial setting and have more leadership training and responsibilities.
De Jonckheere J.F.,De Duve Institute |
De Jonckheere J.F.,Scientific Institute of Public Health
Infection, Genetics and Evolution | Year: 2011
Naegleria fowleri, a worldwide distributed pathogen, is the causative agent of primary amoebic meningoencephalitis. Because it is such a fulminant disease, most patients do not survive the infection. This pathogen is a free-living amoeboflagellate present in warm water. To date, it is well established that there are several types of N. fowleri, which can be distinguished based on the length of the internal transcribed spacer 1 and a one bp transition in the 5.8S rDNA. Seven of the eight known types have been detected in Europe. Three types are present in the USA, of which one is unique to this country. Only one of the eight types occurs in Oceania (Australia and New Zealand) and Japan. In mainland Asia (India, China and Thailand) the two most common types are found, which are also present in Europe and the USA. There is strong indication that the pathogenic N. fowleri evolved from the nonpathogenic Naegleria lovaniensis on the American continent. There is no evidence of virulence differences between the types of N. fowleri. Two other Naegleria spp. are pathogenic for mice, but human infections due to these two other Naegleria spp. are not known. © 2011 Elsevier B.V.
De Jonckheere J.F.,de Duve Institute |
De Jonckheere J.F.,Scientific Institute of Public Health
Experimental Parasitology | Year: 2014
In this short overview of the genus Naegleria a brief historical sketch is given since the discovery of this amoeboflagellate in 1899 and the finding in 1970 that one species, Naegleria fowleri causes primary amoebic meningoencephalitis in man. Eight different types of this pathogen are known which have an uneven distribution over the world. Until now 47 different Naegleria spp. are described, of which two other species cause disease in experimental animals, and their geographical dispersal is indicated. The presence of group I introns in the SSU and in the LSU rDNA in the genus is discussed, as well as the possibility of sex or mating. It is also mentioned that the genome of N. fowleri should not be compared to that of Naegleria gruberi, to know why the former is pathogenic, but to the genome of its closest relative Naegleria lovaniensis. © 2014 Published by Elsevier Inc.
Gaide Chevronnay H.P.,De Duve Institute |
Lemoine P.,De Duve Institute |
Courtoy P.J.,De Duve Institute |
Marbaix E.,De Duve Institute |
Henriet P.,De Duve Institute
Endocrinology | Year: 2010
Explants from nonmenstrual endometria cultured in the absence of ovarian hormones undergo tissue breakdown. Addition of estradiol and progesterone (EP) prevents proteolysis. Explants include stromal and epithelial compartments which play different but complementary roles in endometrial physiology, including tissue remodeling and hormonal response. In order to characterize the cell type-specific contribution to regulation of tissue breakdown, we characterized the transcriptomes of microdissected stromal and glandular areas from endometrial explants cultured with or without EP. The datasets were also compared to other published endometrial transcriptomes. Finally, the contribution of proteolysis, hypoxia, and MAPKs to the regulation of selected genes was further investigated in explant culture. This analysis identified distinct gene expression profiles in stroma and glands, with differential response to EP, but functional clustering underlined convergence in biological processes, further indicating that endometrial remodeling requires cooperation between the two compartments through expression of cell type-specific genes. Only partial overlaps were observed between lists of genes involved in different occurrences of endometrial breakdown, pointing to a limited number of potentially crucial regulators but also to the requirement for additional mechanisms controlling tissue remodeling. We identified a group of genes differentially regulated by EP in stroma and glands among which some were sensitive to MAPKs and/or aspartic proteinases and were not induced by hypoxia. In conclusion, MAPKs and/or aspartic proteinases likely act in concert with EP to locally and specifically control differential expression of genes between degrading and preserved areas of the human endometrium. Copyright © 2010 by The Endocrine Society.
Baeyens N.,Catholic University of Louvain |
Horman S.,Catholic University of Louvain |
Vertommen D.,De Duve Institute |
Rider M.,De Duve Institute |
Morel N.,Catholic University of Louvain
American Journal of Physiology - Cell Physiology | Year: 2010
Ezrin, radixin, and moesin (ERM) proteins are known to be substrates of Rho kinase (ROCK), a key player in vascular smooth muscle regulation. Their function in arteries remains to be elucidated. The objective of the present study was to investigate ERM phosphorylation and function in rat aorta and mesenteric artery and the influence of ERM-binding phosphoprotein 50 (EBP50), a scaffold partner of ERM proteins in several cell types. In isolated arteries, ERM proteins are phosphorylated by PKC and ROCK with different kinetics after either agonist stimulation or KCl-induced depolarization. Immunoprecipitation of EBP50 in noradrenaline-stimulated arteries allowed identification of its interaction with moesin and several other proteins involved in cytoskeleton regulation. This interaction was inhibited by Y27632, a ROCK inhibitor. Moesin or EBP50 depletion after small interfering RNA transfection by reverse permeabilization in intact mesenteric arteries both potentiated the contractility in response to agonist stimulation without any effect on contractile response induced by high KCl. This effect was preserved in ionomycin-permeabilized arteries. These results indicate that, in agonist-stimulated arteries, the activation of ROCK leads to the binding of moesin to EBP50, which interacts with several components of the cytoskeleton, resulting in a decrease in the contractile response. Copyright © 2010 the American Physiological Society.
de Smet C.,De Duve institute |
Loriot A.,De Duve institute
Epigenetics | Year: 2010
Cytosine methylation is a heritable modification of DNA in mammalian cells, and has a determinant impact on long-term gene repression and genome stability. Genomic methylation patterns, which remain generally stable in the adult, become profoundly altered in most human tumors. while discrete DNA segments become hypermethylated in cancer cells, many more sequences become hypomethylated. This review discusses our current understanding of the mechanisms that lead to DNA hypomethylation in tumors. evidence suggests that methylation losses are not random, but rather evolve into mosaic hypomethylation patterns. it is proposed that such hypomethylation patterns result from a historical event of transient DNA demethylation and that transcriptional regulators contribute to determining which regions escape remethylation and remain therefore unmethylated. Finally, possible stages of tumor development during which the transient DNA demethylation process may take place will be discussed. © 2010 Landes Bioscience.
De Duve C.,De Duve Institute
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2011
The origin of life on Earth may be divided into two stages separated by the first appearance of replicable molecules, most probably of RNA. The first stage depended exclusively on chemistry. The second stage likewise involved chemistry, but with the additional participation of selection, a necessary concomitant of inevitable replication accidents. Consideration of these two processes suggests that the origin of life may have been close to obligatory under the physical-chemical conditions that prevailed at the site of its birth. Thus, an extrasolar planet in which those conditions were replicated appears as a probable site for the appearance of extra-terrestrial life. © 2011 The Royal Society.
Agency: European Commission | Branch: FP7 | Program: MC-IRG | Phase: FP7-PEOPLE-2009-RG | Award Amount: 100.00K | Year: 2011
The protein L-isoaspartyl methyltransferase (PIMT) is well known for its protein repair function, namely the reconversion of deamidated and/or isomerized asparaginyl and aspartyl residues (L-isoaspartyl residues) into their normal, non-isomerized forms. The conversion of biomolecules to non-useful and potentially toxic products by unwanted chemical reactions represents probably an important aspect of the aging process in living organisms. To the extent that they can minimize the accumulation of damaged molecules, they can endure. PIMT knockout mice accumulate high levels of damaged proteins in their tissues, especially the brain, and die of massive seizures at an average age of 42 days. On the other hand, worms and flies overexpressing this enzyme live longer, strongly suggesting a role for PIMT in the aging process. A particularly intriguing observation is that the insulin/IGF-1 signaling pathway is activated in the brain of PIMT knockout mice. Genetic evidence also exists for an interaction between PIMT and insulin-like signaling in Caenorhabditis elegans. It has recently become clear that insulin-like signaling plays an important role in the regulation of the aging process. Lowered insulin/IGF-1 signaling, especially in neuronal tissues, leads to lifespan extension in worms, flies and mice. The overall objective of this project is to understand the link between PIMT and insulin-like signaling. A first aim is to consolidate the interaction between PIMT and insulin-like signaling in worms. A second aim is to analyze the effect of PIMT deficiency on the phosphoproteome of mouse brains. A third aim is to elucidate the mechanism by which PIMT deficiency leads to the observed changes in protein phosphorylation. Several routes, including direct regulation of protein phosphatase activity by PIMT methylation, modulation of such an activity by a critical isoaspartyl residue, and effect of high isoaspartyl content in a protein on its phosphorylation state will be explored.