66 results on '"Eggermont K"'
Search Results
2. Optimized lentiviral vector production and purification procedure prevents immune response after transduction of mouse brain
- Author
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Baekelandt, V, Eggermont, K, Michiels, M, Nuttin, B, and Debyser, Z
- Published
- 2003
- Full Text
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3. In vitro modeling of dysfunctional glial cells in neurodegenerative diseases using human pluripotent stem cells
- Author
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García León, Juan Antonio, Eggermont, K, Neyrinck, K, Davila, Jose Carlos, Vitorica, Javier, Verfaillie, C, and Gutierrez-Perez, Antonia
- Abstract
Most neurodegenerative diseases are characterized by a complex and mostly still unresolved pathology. This fact, together with the lack of reliable models, have precluded the development of effective therapies counteracting the disease progression. In the past few years, several studies have evidenced that lack of proper functionality of glial cells (astrocytes, microglia and oligodendrocytes) has a key role in the pathology of several neurodegenerative conditions including Alzheimer´s disease, amyotrophic lateral sclerosis and multiple sclerosis among others. However, this glial dysfunction is poorly modelled by available animal models, and we hypothesize that patientderived cells can serve as a better platform where to study this glial dysfunction. In this sense, human pluripotent stem cells (hPSCs) has revolutionized the field allowing the generation of disease-relevant neural cell types that can be used for disease modelling, drug screening and, possibly, cell transplantation purposes. In the case of the generation of oligodendrocytes (OLs) from hPSCs, we have developed a fast and robust protocol to generate surface antigen O4-positive (O4+) and myelin basic protein-positive OLs from hPSCs in only 22 days, including from patients with multiple sclerosis or amyotrophic lateral sclerosis. The generated cells resemble primary human OLs at the transcriptome level and can myelinate neurons in vivo. Using in vitro OLneuron co-cultures, effective myelination of neurons can also be demonstrated. This platform is being translated as well to the generation of the other glial cell types, allowing the derivation of patient-specific glial cells where to model disease-specific dysfunction. This methodology can be used for elucidating pathogenic pathways associated with neurodegeneration and to identify therapeutic targets susceptible of drug modulation, contributing to the development of novel and effective drugs for these devastating disorders. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Supported by PI18/01557 (to AG) and P18/1556 (to JV) grants from ISCiii of Spain co-financed by FEDER funds from European Union, and PI-0276-2018 grant (to JAGL) from Consejeria de Salud of Junta de Andalucia. JAGL held a postdoctoral contract from the I Research Plan Propio of the University of Malaga. CV and KE were supported by IWT-SBO-150031-iPSCAF and the Thierry Lathran Foundation grant – ALS-OL, and KN by FWO1166518N
- Published
- 2019
4. SOX10 Single Transcription Factor-Based Fast and Efficient Generation of Oligodendrocytes from Human Pluripotent Stem Cells
- Author
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García-León, J.A. (Juan Antonio), Kumar, M. (Manoj), Boon, R. (Ruben), Chau, D. (David), One, J. (Jennifer), Wolfs, E. (Esther), Eggermont, K. (Kristel), Berckmans, P. (Pieter), Gunhanlar, N. (Nilhan), Vrij, F.M.S. (Femke), Lendemeijer, B. (Bas), Pavie, B. (Benjamin), Corthout, N. (Nikky), Kushner, S.A. (Steven A.), Dávila, J.C. (José Carlos), Lambrichts, I. (Ivo), Hu, W.-S. (Wei-Shou), Verfaillie, C.M. (Catherine M.), García-León, J.A. (Juan Antonio), Kumar, M. (Manoj), Boon, R. (Ruben), Chau, D. (David), One, J. (Jennifer), Wolfs, E. (Esther), Eggermont, K. (Kristel), Berckmans, P. (Pieter), Gunhanlar, N. (Nilhan), Vrij, F.M.S. (Femke), Lendemeijer, B. (Bas), Pavie, B. (Benjamin), Corthout, N. (Nikky), Kushner, S.A. (Steven A.), Dávila, J.C. (José Carlos), Lambrichts, I. (Ivo), Hu, W.-S. (Wei-Shou), and Verfaillie, C.M. (Catherine M.)
- Abstract
Scarce access to primary samples and lack of efficient protocols to generate oligodendrocytes (OLs) from human pluripotent stem cells (hPSCs) are hampering our understanding of OL biology and the development of novel therapies. Here, we demonstrate that overexpression of the transcription factor SOX10 is sufficient to generate surface antigen O4-positive (O4+) and myelin basic protein-positive OLs from hPSCs in only 22 days, including from patients with multiple sclerosis or amyotrophic lateral sclerosis. The SOX10-induced O4+ population resembles primary human OLs at the transcriptome level and can myelinate neurons in vivo. Using in vitro OL-neuron co-cultures, myelination of neurons by OLs can also be demonstrated, which can be adapted to a high-throughput screening format to test the response of pro-myelinating drugs. In conclusion, we provide an approach to generate OLs in a very rapid and efficient manner, which can be used for disease modeling, drug discovery efforts, and potentially for therapeutic OL transplantation. In this article, García-León JA and colleagues demonstrate the generation of functional oligodendrocytes (OLs) from human pluripotent stem cells in a rapid and efficient manner by the single overexpression of SOX10. Generated OLs resemble primary OLs at the transcriptome level and can myelinate neurons both in vivo and in vitro. Neuron-OL co-cultures, adapted to high-throughput screening formats, responded to drugs affecting myelination.
- Published
- 2018
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5. SOX10 Single Transcription Factor-Based Fast and Efficient Generation of Oligodendrocytes from Human Pluripotent Stem Cells
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Garcia-Leon, JA, Kumar, M, Boon, R, Chau, D, One, J, Wolfs, E, Eggermont, K, Berckmans, P, Gunhanlar, Nilhan, de Vrij, Femke, Lendemeijer, Bas, Pavie, B, Corthout, N, Kushner, Steven, Davila, JC, Lambrichts, I, Hu, WS, Verfaillie, CM, Garcia-Leon, JA, Kumar, M, Boon, R, Chau, D, One, J, Wolfs, E, Eggermont, K, Berckmans, P, Gunhanlar, Nilhan, de Vrij, Femke, Lendemeijer, Bas, Pavie, B, Corthout, N, Kushner, Steven, Davila, JC, Lambrichts, I, Hu, WS, and Verfaillie, CM
- Published
- 2018
6. P110 GENE EXPRESSION DURING HEPATOCYTE DIFFERENTIATION DRIVEN BY EPIGENETIC CHANGES: VIA PROMOTERS OR ENHANCERS?
- Author
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Vanhove, J., primary, Pistoni, M., additional, Welters, M., additional, Eggermont, K., additional, Vanslembrouck, V., additional, Collas, P., additional, Voncken, W., additional, and Verfaillie, C.M., additional
- Published
- 2014
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7. The Arabidopsis mutant iop1 exhibits induced over-expression of the plant defensin gene PDF1.2 and enhanced pathogen resistance
- Author
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Penninckx, I.A.M.A., Eggermont, K., Schenk, P.M., van den Ackerveken, G., Cammue, B.P.A., and Thomma, B.P.H.J.
- Subjects
methyl-jasmonate ,EPS-2 ,fungi ,cev1 ,cell-death ,Laboratorium voor Phytopathologie ,salicylic-acid ,Laboratory of Phytopathology ,activation ,thaliana ,fungal pathogens ,response pathways ,protein ,induction - Abstract
Jasmonate and ethylene are concomitantly involved in the induction of the Arabidopsis plant defensin gene PDF1.2. To define genes in the signal transduction pathway leading to the induction of PDF1.2, we screened for mutants with induced over-expression of a β-glucuronidase reporter, under the control of the PDF1.2 promoter. One mutant, iop1 (induced over-expressor of PDF1.2) produced small plants that showed induced over-expression of the pathogenesis-related genes PR-3, PR-4 and PR-1,2 (PDF1.2), combined with a down-regulated induction of PR-1 upon pathogen inoculation. The iop1 mutant showed enhanced resistance to a number of necrotrophic pathogens.
- Published
- 2003
8. Travel cost and time measurement in travel cost models
- Author
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Moons, Ellen, Loomis, J, Proost, Stef, Eggermont, K, and Hermy, Martin
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Measurement ,Cost ,Models ,Working ,Model ,Time - Abstract
In this paper we use the results of a recent on-site recreation survey to know whether it matters to use perceived rather than calculated travel costs. The calculated travel costs (time and money) are derived from detailed GIS computations. The perceived travel times and costs are taken directly from the survey responses. We first find that there is a high non-response rate for the perceived cost question. For those who respond we find that the perceived costs are close to the sum of the calculated time and fuel costs. The relative difference between perceived and calculated costs is negatively related to distance and visit frequency. We explain perceived costs by simple factors such as distance, time, group size, social class, education level, length of stay and general satisfaction with their visit. To examine the effect of the specification of the travel cost and time variables, we estimate several individual trip demand equations for three functional forms of the dependent variable: semi-log, negative binomial and truncated negative binomial. Based on the log-likelihood values of the estimation of the different trip demand equations we show that there are no significant differences in model performance as far as cost specifications are concerned. Comparing cost coefficients and consequently consumer surplus estimates shows that only for the negative binomial functional form there is a statistically significant difference between the specification with perceived costs and the model with total calculated cost measures. ispartof: Working Papers pages:1-22 status: published
- Published
- 2001
9. Economische waardering van bossen - een case study voor Heverleebos-Meerdaalwoud
- Author
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Proost, S., Moons, E., Nunes, P.A.L.D., Hermy, M., Eggermont, K., van Ierland, E., and Loomis, J.B.
- Published
- 2000
10. Begrazing van natuurgebieden in vlaanderen:eindrapport
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Eggermont, K, Hermy, M, and De Blust, Geert
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Vlaanderen ,Regulier beheer ,B003-ecologie ,natuurbeheer - Published
- 1996
11. Pathogen-induced systemic activation of a plant defensin gene in Arabidopsis follows a salicylic acid-independent pathway.
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Penninckx, I A, primary, Eggermont, K, additional, Terras, F R, additional, Thomma, B P, additional, De Samblanx, G W, additional, Buchala, A, additional, Métraux, J P, additional, Manners, J M, additional, and Broekaert, W F, additional
- Published
- 1996
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12. A Potent Antimicrobial Protein from Onion Seeds Showing Sequence Homology to Plant Lipid Transfer Proteins
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Cammue, BPA., primary, Thevissen, K., additional, Hendriks, M., additional, Eggermont, K., additional, Goderis, I. J., additional, Proost, P., additional, Van Damme, J., additional, Osborn, R. W., additional, Guerbette, F., additional, Kader, J. C., additional, and Broekaert, W. F., additional
- Published
- 1995
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13. Small cysteine-rich antifungal proteins from radish: their role in host defense.
- Author
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Terras, F R, primary, Eggermont, K, additional, Kovaleva, V, additional, Raikhel, N V, additional, Osborn, R W, additional, Kester, A, additional, Rees, S B, additional, Torrekens, S, additional, Van Leuven, F, additional, and Vanderleyden, J, additional
- Published
- 1995
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14. Disease development of several fungi on Arabidopsis can be reduced by treatment with methyl jasmonate
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Thomma, B. P. H. J., Eggermont, K., Broekaert, W. F., and Cammue, B. P. A.
- Published
- 2000
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15. Requirement of functional ethylene-insensitive 2 gene for efficient resistance of Arabidopsis to infection by Botrytis cinerea.
- Author
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Thomma, B P, Eggermont, K, Tierens, K F, and Broekaert, W F
- Abstract
Inoculation of wild-type Arabidopsis plants with the fungus Alternaria brassicicola results in systemic induction of genes encoding a plant defensin (PDF1.2), a basic chitinase (PR-3), and an acidic hevein-like protein (PR-4). Pathogen-induced induction of these three genes is almost completely abolished in the ethylene-insensitive Arabidopsis mutant ein2-1. This indicates that a functional ethylene signal transduction component (EIN2) is required in this response. The ein2-1 mutants were found to be markedly more susceptible than wild-type plants to infection by two different strains of the gray mold fungus Botrytis cinerea. In contrast, no increased fungal colonization of ein2-1 mutants was observed after challenge with avirulent strains of either Peronospora parasitica or A. brassicicola. Our data support the conclusion that ethylene-controlled responses play a role in resistance of Arabidopsis to some but not all types of pathogens.
- Published
- 1999
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16. Induced pluripotent stem cell-derived neuronal cultures as a model to study ZIKA virus infections and antivirals
- Author
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Lanko, K., Kaptein, S., Eggermont, K., Patel, A., Claes, C., Guo, W., Damme, P., Den Bosch, L., Delang, L., Verfaillie, C., and Johan NEYTS
17. Mental illness and identity in adolescents with internalizing problems: A qualitative exploration of identity-relevant narratives.
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de Moor EL, Campens S, Eggermont K, Raemen L, Vanderhaegen J, Vankerckhoven L, van Laere E, Bogaerts A, Koster N, Branje S, Claes L, and Luyckx K
- Abstract
Mental illness and identity are related, with issues in identity contributing to the development of psychopathology and vice versa. However, little work has examined how mental illness and identity can become interwoven (i.e., mental illness identity). Mental illness identity may be particularly important during adolescence, as this life phase is marked by the salience of identity and an increase in psychopathology. In the present study, we conducted a qualitative examination of the high point, low point, turning point, and psychopathology-related narratives of 69 Dutch adolescents ( M
age = 16.5, 75.4% female, 15.9% male, 8.7% other). The participants were diagnosed with a mood, anxiety, and/or eating disorder, and the majority of them (82.6%) were in treatment at the time of the study. We found that adolescents' mental illness identity could take different forms and that these forms may be more adaptive or maladaptive depending on the context of each adolescent's life. Furthermore, mental illness identity was related to several factors within adolescents (e.g., sense of agency) and their environment (e.g., stigma). These findings contribute to our understanding of adolescent mental illness identity and may be used to improve the treatment of their internalizing problems. (PsycInfo Database Record (c) 2024 APA, all rights reserved).- Published
- 2024
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18. PMP22 duplication dysregulates lipid homeostasis and plasma membrane organization in developing human Schwann cells.
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Prior R, Silva A, Vangansewinkel T, Idkowiak J, Tharkeshwar AK, Hellings TP, Michailidou I, Vreijling J, Loos M, Koopmans B, Vlek N, Agaser C, Kuipers TB, Michiels C, Rossaert E, Verschoren S, Vermeire W, de Laat V, Dehairs J, Eggermont K, van den Biggelaar D, Bademosi AT, Meunier FA, vandeVen M, Van Damme P, Mei H, Swinnen JV, Lambrichts I, Baas F, Fluiter K, Wolfs E, and Van Den Bosch L
- Subjects
- Animals, Humans, Mice, Gene Duplication, Sciatic Nerve metabolism, Cell Membrane metabolism, Charcot-Marie-Tooth Disease genetics, Charcot-Marie-Tooth Disease metabolism, Charcot-Marie-Tooth Disease pathology, Homeostasis physiology, Induced Pluripotent Stem Cells metabolism, Lipid Metabolism physiology, Myelin Proteins metabolism, Myelin Proteins genetics, Schwann Cells metabolism
- Abstract
Charcot-Marie-Tooth disease type 1A (CMT1A) is the most common inherited peripheral neuropathy caused by a 1.5 Mb tandem duplication of chromosome 17 harbouring the PMP22 gene. This dose-dependent overexpression of PMP22 results in disrupted Schwann cell myelination of peripheral nerves. To obtain better insights into the underlying pathogenic mechanisms in CMT1A, we investigated the role of PMP22 duplication in cellular homeostasis in CMT1A mouse models and in patient-derived induced pluripotent stem cells differentiated into Schwann cell precursors (iPSC-SCPs). We performed lipidomic profiling and bulk RNA sequencing (RNA-seq) on sciatic nerves of two developing CMT1A mouse models and on CMT1A patient-derived iPSC-SCPs. For the sciatic nerves of the CMT1A mice, cholesterol and lipid metabolism was downregulated in a dose-dependent manner throughout development. For the CMT1A iPSC-SCPs, transcriptional analysis unveiled a strong suppression of genes related to autophagy and lipid metabolism. Gene ontology enrichment analysis identified disturbances in pathways related to plasma membrane components and cell receptor signalling. Lipidomic analysis confirmed the severe dysregulation in plasma membrane lipids, particularly sphingolipids, in CMT1A iPSC-SCPs. Furthermore, we identified reduced lipid raft dynamics, disturbed plasma membrane fluidity and impaired cholesterol incorporation and storage, all of which could result from altered lipid storage homeostasis in the patient-derived CMT1A iPSC-SCPs. Importantly, this phenotype could be rescued by stimulating autophagy and lipolysis. We conclude that PMP22 duplication disturbs intracellular lipid storage and leads to a more disordered plasma membrane owing to an alteration in the lipid composition, which might ultimately lead to impaired axo-glial interactions. Moreover, targeting lipid handling and metabolism could hold promise for the treatment of patients with CMT1A., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain.)
- Published
- 2024
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19. A brief screener for impairment in personality functioning: Psychometric validation of the Five-Item Screening Scale for Personality Disorders in a Dutch-speaking clinical sample.
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Eggermont K, Smits D, Bogaerts A, Pauwels E, Dierckx E, Luyckx K, and Claes L
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- Humans, Female, Male, Adult, Middle Aged, Reproducibility of Results, Netherlands, Young Adult, Psychiatric Status Rating Scales standards, Adolescent, Aged, Personality Disorders diagnosis, Psychometrics standards
- Abstract
Personality disorders (PDs) are characterized by problems with identity and self-direction. Since the recent dimensional PD models of the Diagnostic and Statistical Manual of Mental Disorders , fifth edition ( DSM-5 ) and the International Statistical Classification of Diseases and Related Health Problems, 11th edition, the role of identity and self-direction in personality pathology has been made explicitly by including these problems in a general personality pathology criterion. This criterion reflects impairment in personality functioning (IPF), which is assessed on a continuum to determine the severity of personality pathology. The present study aimed to psychometrically evaluate the Five-Item Screening Scale for Personality Disorders (FISSPD; Skodol et al., 2011), a short screener for IPF, in a Dutch-speaking clinical sample of 820 adults. This screener mainly taps into self-related impairment, with four items measuring self-related impairment and one item measuring interpersonal impairment. The factor structure, scale reliability, measurement invariance (across sex, age, and patients with vs. without PD), and convergent validity were investigated. The Dutch FISSPD showed a unidimensional structure and good scale reliability. Scalar measurement invariance was established across sex, age (patients below vs. above age 40), and patients with versus without PD. The Dutch FISSPD was significantly related to identity and all DSM-IV/5 Section-II PD symptoms. The present study indicates that the Dutch FISSPD has potential as a reliable and valid screener for personality pathology in adult patients. (PsycInfo Database Record (c) 2024 APA, all rights reserved).
- Published
- 2024
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20. Molecular insights into PCB neurotoxicity: Comparing transcriptomic responses across dopaminergic neurons, population blood cells, and Parkinson's disease pathology.
- Author
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Krauskopf J, Eggermont K, Caiment F, Verfaillie C, and de Kok TM
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- Humans, Blood Cells drug effects, Induced Pluripotent Stem Cells drug effects, Induced Pluripotent Stem Cells metabolism, Environmental Pollutants toxicity, Polychlorinated Biphenyls toxicity, Parkinson Disease, Dopaminergic Neurons drug effects, Transcriptome drug effects
- Abstract
Parkinson's disease (PD) is a complex neurodegenerative disorder influenced by genetic factors and environmental exposures. Polychlorinated biphenyls (PCBs), a group of synthetic organic compounds, have been identified as potential environmental risk factors for neurodegenerative diseases, including PD. We explored PCB-induced neurotoxicity mechanisms using iPSC-derived dopaminergic neurons and assessed their transcriptomic responses to varying PCB concentrations (0.01 μM, 0.5 μM, and 10 μM). Specifically, we focused on PCB-180, a congener known for its accumulation in human brains. The exposure durations were 24 h and 74 h, allowing us to capture both short-term and more prolonged effects on gene expression patterns. We observed that PCB exposure led to the suppression of oxidative phosphorylation, synaptic function, and neurotransmitter release, implicating these pathways in PCB-induced neurotoxicity. In our comparative analysis, we noted similarities in PCB-induced changes with other PD-related compounds like MPP+ and rotenone. Our findings also aligned with gene expression changes in human blood derived from a population exposed to PCBs, highlighting broader inflammatory responses. Additionally, molecular patterns seen in iPSC-derived neurons were confirmed in postmortem PD brain tissues, validating our in vitro results. In conclusion, our study offers novel insights into the multifaceted impacts of PCB-induced perturbations on various cellular contexts relevant to PD. The use of iPSC-derived dopaminergic neurons allowed us to decipher intricate transcriptomic alterations, bridging the gap between in vitro and in vivo findings. This work underscores the potential role of PCB exposure in neurodegenerative diseases like PD, emphasizing the need to consider both systemic and cell specific effects., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2024
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21. DJ-1 is an essential downstream mediator in PINK1/parkin-dependent mitophagy.
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Imberechts D, Kinnart I, Wauters F, Terbeek J, Manders L, Wierda K, Eggermont K, Madeiro RF, Sue C, Verfaillie C, and Vandenberghe W
- Subjects
- Humans, Mitochondria metabolism, Ubiquitin-Protein Ligases genetics, Mitophagy genetics, Mitophagy physiology, Parkinson Disease metabolism, Protein Kinases genetics
- Abstract
Loss-of-function mutations in the PRKN, PINK1 and PARK7 genes (encoding parkin, PINK1 and DJ-1, respectively) cause autosomal recessive forms of Parkinson's disease. PINK1 and parkin jointly mediate selective autophagy of damaged mitochondria (mitophagy), but the mechanisms by which loss of DJ-1 induces Parkinson's disease are not well understood. Here, we investigated PINK1/parkin-mediated mitophagy in cultured human fibroblasts and induced pluripotent stem cell-derived neurons with homozygous PARK7 mutations. We found that DJ-1 is essential for PINK1/parkin-mediated mitophagy. Loss of DJ-1 did not interfere with PINK1 or parkin activation after mitochondrial depolarization but blocked mitophagy further downstream by inhibiting recruitment of the selective autophagy receptor optineurin to depolarized mitochondria. By contrast, starvation-induced, non-selective autophagy was not affected by loss of DJ-1. In wild-type fibroblasts and induced pluripotent stem cell-derived dopaminergic neurons, endogenous DJ-1 translocated to depolarized mitochondria in close proximity to optineurin. DJ-1 translocation to depolarized mitochondria was dependent on PINK1 and parkin and did not require oxidation of cysteine residue 106 of DJ-1. Overexpression of DJ-1 did not rescue the mitophagy defect of PINK1- or parkin-deficient cells. These findings position DJ-1 downstream of PINK1 and parkin in the same pathway and suggest that disruption of PINK1/parkin/DJ-1-mediated mitophagy is a common pathogenic mechanism in autosomal recessive Parkinson's disease., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Guarantors of Brain.)
- Published
- 2022
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22. Transcriptomics analysis of human iPSC-derived dopaminergic neurons reveals a novel model for sporadic Parkinson's disease.
- Author
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Krauskopf J, Eggermont K, Madeiro Da Costa RF, Bohler S, Hauser D, Caiment F, de Kok TM, Verfaillie C, and Kleinjans JC
- Subjects
- Humans, Dopaminergic Neurons metabolism, Transcriptome genetics, Parkinson Disease genetics, Parkinson Disease metabolism, Induced Pluripotent Stem Cells metabolism, Neurodegenerative Diseases metabolism
- Abstract
Parkinson's disease (PD) is a progressive, neurodegenerative disease affecting over 1% of the population beyond 65 years of age. Although some PD cases are inheritable, the majority of PD cases occur in a sporadic manner. Risk factors comprise next to heredity, age, and gender also exposure to neurotoxins from for instance pesticides and herbicides. As PD is characterized by a loss of dopaminergic neurons in the substantia nigra, it is nearly impossible to access and extract these cells from patients for investigating disease mechanisms. The emergence of induced pluripotent stem (iPSC) technology allows differentiating and growing human dopaminergic neurons, which can be used for in vitro disease modeling. Here, we differentiated human iPSCs into dopaminergic neurons, and subsequently exposed the cells to increasing concentrations of the neurotoxin MPP
+ . Temporal transcriptomics analysis revealed a strong time- and dose-dependent response with genes over-represented across pathways involved in PD etiology such as "Parkinson's Disease", "Dopaminergic signaling" and "calcium signaling". Moreover, we validated this disease model by showing robust overlap with a meta-analysis of transcriptomics data from substantia nigra from post-mortem PD patients. The overlap included genes linked to e.g. mitochondrial dysfunction, neuron differentiation, apoptosis and inflammation. Our data shows, that MPP+ -induced, human iPSC-derived dopaminergic neurons present molecular perturbations as observed in the etiology of PD. Therefore we propose iPSC-derived dopaminergic neurons as a foundation for a novel sporadic PD model to study the pathomolecular mechanisms of PD, but also to screen for novel anti-PD drugs and to develop and test new treatment strategies., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)- Published
- 2022
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23. Do Gender and Age Moderate the Relationship between Friendship Quality and Non-Suicidal Self-Injury in Community Children and Adolescents?
- Author
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Eggermont K, Bastin M, Luyckx K, and Claes L
- Abstract
In the present study, we investigated the relationship between friendship quality (dimensions) and non-suicidal self-injury (NSSI) as well as the moderating role of gender and age in this relationship. The sample consisted of 463 children and adolescents (50.10% female, age range: 9-17 years). Friendship quality and NSSI were measured using the Friendship Qualities Scale (FQS; Bukowski, Hoza, & Boivin, 1994) and the Self Harm Inventory (SHI; Sansone, Wiederman, & Sansone, 1998), respectively. Overall, total friendship quality and NSSI were significantly and negatively related. Additionally, the relationship between total friendship quality and NSSI was moderated by gender and age. Specifically, girls with low friendship quality reported more NSSI; whereas for boys an opposite effect was found. As for age, friendship quality and NSSI were positively related in older participants. In younger participants, a relationship between friendship quality and NSSI seemed rather absent. This study highlights the important association between friendship quality and NSSI, as well as gender- and age-related differences in this association, which should be taken into account in the prevention and treatment of NSSI., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2021 The Author(s).)
- Published
- 2021
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24. Induced pluripotent stem cell-derived motor neurons of CMT type 2 patients reveal progressive mitochondrial dysfunction.
- Author
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Van Lent J, Verstraelen P, Asselbergh B, Adriaenssens E, Mateiu L, Verbist C, De Winter V, Eggermont K, Van Den Bosch L, De Vos WH, and Timmerman V
- Subjects
- Charcot-Marie-Tooth Disease pathology, Genotype, Humans, Induced Pluripotent Stem Cells metabolism, Induced Pluripotent Stem Cells pathology, Mitochondria pathology, Motor Neurons pathology, Mutation, Pedigree, Charcot-Marie-Tooth Disease metabolism, Mitochondria metabolism, Motor Neurons metabolism
- Abstract
Axonal Charcot-Marie-Tooth neuropathies (CMT type 2) are caused by inherited mutations in various genes functioning in different pathways. The types of genes and multiplicity of mutations reflect the clinical and genetic heterogeneity in CMT2 disease, which complicates its diagnosis and has inhibited the development of therapies. Here, we used CMT2 patient-derived pluripotent stem cells (iPSCs) to identify common hallmarks of axonal degeneration shared by different CMT2 subtypes. We compared the cellular phenotypes of neurons differentiated from CMT2 patient iPSCs with those from healthy controls and a CRISPR/Cas9-corrected isogenic line. Our results demonstrated neurite network alterations along with extracellular electrophysiological abnormalities in the differentiated motor neurons. Progressive deficits in mitochondrial and lysosomal trafficking, as well as in mitochondrial morphology, were observed in all CMT2 patient lines. Differentiation of the same CMT2 iPSC lines into peripheral sensory neurons only gave rise to cellular phenotypes in subtypes with sensory involvement, supporting the notion that some gene mutations predominantly affect motor neurons. We revealed a common mitochondrial dysfunction in CMT2-derived motor neurons, supported by alterations in the expression pattern and oxidative phosphorylation, which could be recapitulated in the sciatic nerve tissue of a symptomatic mouse model. Inhibition of a dual leucine zipper kinase could partially ameliorate the mitochondrial disease phenotypes in CMT2 subtypes. Altogether, our data reveal shared cellular phenotypes across different CMT2 subtypes and suggests that targeting such common pathomechanisms could allow the development of a uniform treatment for CMT2., (© The Author(s) (2021). Published by Oxford University Press on behalf of the Guarantors of Brain.)
- Published
- 2021
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25. HDAC6 inhibition restores TDP-43 pathology and axonal transport defects in human motor neurons with TARDBP mutations.
- Author
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Fazal R, Boeynaems S, Swijsen A, De Decker M, Fumagalli L, Moisse M, Vanneste J, Guo W, Boon R, Vercruysse T, Eggermont K, Swinnen B, Beckers J, Pakravan D, Vandoorne T, Vanden Berghe P, Verfaillie C, Van Den Bosch L, and Van Damme P
- Subjects
- Amyotrophic Lateral Sclerosis genetics, Cells, Cultured, DNA-Binding Proteins metabolism, Histone Deacetylase 6 antagonists & inhibitors, Histone Deacetylase Inhibitors pharmacology, Humans, Induced Pluripotent Stem Cells cytology, Mitochondria metabolism, Motor Neurons cytology, Motor Neurons drug effects, Mutation, Missense, Amyotrophic Lateral Sclerosis metabolism, Axonal Transport, DNA-Binding Proteins genetics, Histone Deacetylase 6 metabolism, Motor Neurons metabolism
- Abstract
TDP-43 is the major component of pathological inclusions in most ALS patients and in up to 50% of patients with frontotemporal dementia (FTD). Heterozygous missense mutations in TARDBP, the gene encoding TDP-43, are one of the common causes of familial ALS. In this study, we investigate TDP-43 protein behavior in induced pluripotent stem cell (iPSC)-derived motor neurons from three ALS patients with different TARDBP mutations, three healthy controls and an isogenic control. TARDPB mutations induce several TDP-43 changes in spinal motor neurons, including cytoplasmic mislocalization and accumulation of insoluble TDP-43, C-terminal fragments, and phospho-TDP-43. By generating iPSC lines with allele-specific tagging of TDP-43, we find that mutant TDP-43 initiates the observed disease phenotypes and has an altered interactome as indicated by mass spectrometry. Our findings also indicate that TDP-43 proteinopathy results in a defect in mitochondrial transport. Lastly, we show that pharmacological inhibition of histone deacetylase 6 (HDAC6) restores the observed TDP-43 pathologies and the axonal mitochondrial motility, suggesting that HDAC6 inhibition may be an interesting therapeutic target for neurodegenerative disorders linked to TDP-43 pathology., (© 2021 The Authors. Published under the terms of the CC BY 4.0 license.)
- Published
- 2021
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26. Dorsal Pancreas Agenesis in an Organ Donor: To Accept or to Discard for Transplantation?
- Author
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De Beule J, Monbaliu D, Eggermont K, Sutherland DER, Gruessner RWG, Pirenne J, and Ceulemans LJ
- Abstract
Competing Interests: J.P. declares unrelated disclosures: he holds named chairs at the KU Leuven from the Institut Georges Lopez and from the “Centrale Afdeling voor Fractionering” (DGF-CAF). L.J.C. is supported by an unrelated KU Leuven University Chair funded by Medtronic. J.D.B. holds a PhD fellowship fundamental research (1152820 N) from The Research Foundation Flanders (FWO). D.M. is a senior clinical investigator of the Research Foundation Flanders (FWO) (18B1916N). L.J.C. receives a postdoctoral grant from the University Hospitals Leuven (KOOR-UZ Leuven). The other authors declare no conflicts of interest.
- Published
- 2020
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27. Generation of oligodendrocytes and establishment of an all-human myelinating platform from human pluripotent stem cells.
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García-León JA, García-Díaz B, Eggermont K, Cáceres-Palomo L, Neyrinck K, Madeiro da Costa R, Dávila JC, Baron-Van Evercooren A, Gutiérrez A, and Verfaillie CM
- Subjects
- Cell Culture Techniques methods, Cell Line, Humans, Myelin Basic Protein analysis, Myelin Basic Protein metabolism, Neural Stem Cells metabolism, Oligodendroglia metabolism, Pluripotent Stem Cells metabolism, Myelin Sheath metabolism, Neural Stem Cells cytology, Neurogenesis, Oligodendroglia cytology, Pluripotent Stem Cells cytology
- Abstract
Oligodendrocytes (OLs) are responsible for myelin production and metabolic support of neurons. Defects in OLs are crucial in several neurodegenerative diseases including multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS). This protocol describes a method to generate oligodendrocyte precursor cells (OPCs) from human pluripotent stem cells (hPSCs) in only ~20 d, which can subsequently myelinate neurons, both in vitro and in vivo. To date, OPCs have been derived from eight different hPSC lines including those derived from patients with spontaneous and familial forms of MS and ALS, respectively. hPSCs, fated for 8 d toward neural progenitors, are transduced with an inducible lentiviral vector encoding for SOX10. The addition of doxycycline for 10 d results in >60% of cells being O4-expressing OPCs, of which 20% co-express the mature OL marker myelin basic protein (MBP). The protocol also describes an alternative for viral transduction, by incorporating an inducible SOX10 in the safe harbor locus AAVS1, yielding ~100% pure OPCs. O4
+ OPCs can be purified and either cryopreserved or used for functional studies. As an example of the type of functional study for which the derived cells could be used, O4+ cells can be co-cultured with maturing hPSC-derived neurons in 96/384-well-format plates, allowing the screening of pro-myelinating compounds.- Published
- 2020
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28. Detection of Zika Virus Replication in Human Semen by Reverse-Transcription Polymerase Chain Reaction Targeting of Antisense Ribonucleic Acid.
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Huits R, De Smet B, Grard G, Eggermont K, Minto-Bain C, Jess N, Leparc-Goffart I, Malvy D, and Cnops L
- Subjects
- Humans, Male, Reverse Transcriptase Polymerase Chain Reaction, Sensitivity and Specificity, Zika Virus genetics, Zika Virus isolation & purification, RNA, Antisense analysis, RNA, Viral analysis, Semen virology, Virus Replication, Zika Virus physiology, Zika Virus Infection virology
- Abstract
Background: Persistence of Zika virus (ZIKV) ribonucleic acid (RNA) in semen is common after infection., Methods: We designed a reverse-transcription polymerase chain reaction assay that targets antisense ZIKV RNA (asRNA) to assess ZIKV replication competence in ZIKV RNA-positive semen samples., Results: We detected ZIKV asRNA in semen of 9 of 19 men (47.4%) diagnosed with ZIKV infection. All asRNA-positive samples had high ZIKV loads (cycle threshold values <26) and were obtained within 21 days of symptom onset., Conclusions: The sensitivity of the asRNA assay for detection of ZIKV replication was higher than that of conventional virus isolation methods (47.4% vs 21.1%, P = .032)., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)
- Published
- 2020
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29. Incidence of Zika virus infection in a prospective cohort of Belgian travellers to the Americas in 2016.
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Huits R, Van Den Bossche D, Eggermont K, Lotgering E, Feyens AM, Potters I, Jacobs J, Van Esbroeck M, Cnops L, and Bottieau E
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- Adult, Americas epidemiology, Belgium ethnology, Disease Transmission, Infectious, Female, Humans, Incidence, Male, Middle Aged, Prospective Studies, Travel-Related Illness, Young Adult, Zika Virus isolation & purification, Disease Outbreaks, Travel, Zika Virus Infection ethnology
- Abstract
Background: The incidence rate of Zika virus (ZIKV) infection in travellers from non-endemic areas to the Americas during the ZIKV outbreak in 2016 is unknown., Methods: Belgian adults who planned to travel to South America, Central America, and the Caribbean were recruited prospectively to study the incidence and characteristics of ZIKV. Demographic data and sera were collected at baseline. Participants were trained to collect capillary blood on filter paper (BFP). When ill during travel, the participants completed a questionnaire and they sampled BFP for post-hoc analysis. All symptomatic participants were screened for ZIKV using ZIKV-specific RT-PCR on serum or urine, or BFP, and antibody detection assays (ELISA). Follow-up sera of asymptomatic travellers, obtained at least 20 days post travel, were tested by ZIKV ELISA only. All positive ELISA results were subject to confirmation by virus neutralization testing (VNT)., Results: Forty-nine participants completed follow-up: 38 women and 11 men, with a median age of 32 years (range 19-64 years). Travel destinations were countries in South America (n=20), Central America (n=24), and the Caribbean (n=5). The total travel duration was 67.8 person-months. Illness was reported by 24 participants (49.0%). ZIKV infection was confirmed in nine cases, by RT-PCR (n=5) and by VNT (n=4). Only one of nine ZIKV cases (11.1%) was asymptomatic. The ZIKV incidence rate was 17.0% (95% confidence interval 7.8-32.2%) per month of travel., Conclusions: The ZIKV incidence rate in adult travellers from non-endemic countries to the epidemic territories during the 2016 outbreak was high. Asymptomatic ZIKV infection was rare in this population., (Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2019
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30. Generation of a human induced pluripotent stem cell-based model for tauopathies combining three microtubule-associated protein TAU mutations which displays several phenotypes linked to neurodegeneration.
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García-León JA, Cabrera-Socorro A, Eggermont K, Swijsen A, Terryn J, Fazal R, Nami F, Ordovás L, Quiles A, Lluis F, Serneels L, Wierda K, Sierksma A, Kreir M, Pestana F, Van Damme P, De Strooper B, Thorrez L, Ebneth A, and Verfaillie CM
- Subjects
- CRISPR-Cas Systems, Cell Line, Humans, Induced Pluripotent Stem Cells pathology, Membrane Potentials physiology, Mutation, Nerve Degeneration genetics, Nerve Degeneration metabolism, Nerve Degeneration pathology, Neurogenesis physiology, Neuronal Outgrowth physiology, Neurons metabolism, Neurons pathology, Phenotype, Tauopathies genetics, Tauopathies pathology, Transcriptome, tau Proteins genetics, Induced Pluripotent Stem Cells metabolism, Tauopathies metabolism, tau Proteins metabolism
- Abstract
Introduction: Tauopathies are neurodegenerative diseases characterized by TAU protein-related pathology, including frontotemporal dementia and Alzheimer's disease among others. Mutant TAU animal models are available, but none of them faithfully recapitulates human pathology and are not suitable for drug screening., Methods: To create a new in vitro tauopathy model, we generated a footprint-free triple MAPT-mutant human induced pluripotent stem cell line (N279K, P301L, and E10+16 mutations) using clustered regularly interspaced short palindromic repeats-FokI and piggyBac transposase technology., Results: Mutant neurons expressed pathogenic 4R and phosphorylated TAU, endogenously triggered TAU aggregation, and had increased electrophysiological activity. TAU-mutant cells presented deficiencies in neurite outgrowth, aberrant sequence of differentiation to cortical neurons, and a significant activation of stress response pathways. RNA sequencing confirmed stress activation, demonstrated a shift toward GABAergic identity, and an upregulation of neurodegenerative pathways., Discussion: In summary, we generated a novel in vitro human induced pluripotent stem cell TAU-mutant model displaying neurodegenerative disease phenotypes that could be used for disease modeling and drug screening., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2018
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31. Level of parenting stress in mothers of singletons and mothers of twins until one year postpartum: A cross-sectional study.
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De Roose M, Beeckman D, Eggermont K, Vanhouche E, Van Hecke A, and Verhaeghe S
- Subjects
- Adaptation, Psychological, Adult, Cross-Sectional Studies, Female, Humans, Male, Personal Satisfaction, Pregnancy, Social Support, Time Factors, Mothers psychology, Parenting psychology, Postpartum Period psychology, Stress, Psychological psychology, Twins psychology
- Abstract
Problem: To date, it is unclear which factors are associated with parenting stress., Background: There are no studies investigating the association between parenting stress and coping strategies such as coparenting and social support, while simultaneously considering demographic and obstetric factors, in mothers of singletons and twins., Aim: To investigate if parenting stress is associated with personal, and obstetric characteristics, the level of coparenting, and the availability of and satisfaction with social support in mothers of singletons and twins until one year postpartum., Methods: A cross-sectional study was conducted. A total of 151 singleton mothers and 101 twin mothers were included., Results: Both singleton and twin mothers experiencing lower parenting stress levels indicated a better coparenting relationship quality (β=-0.253, p<0.01; β=-0.341, p=0.001). Elevated parenting stress levels positively influenced the level of satisfaction with social support in only mothers of twins (β=0.273, p<0.01). The availability of social support, personal, and obstetric characteristics were not associated with the level of parenting stress in neither singleton nor twin mothers., Conclusion: Coparenting seems to be a significant coping strategy reducing the level of parenting stress in singleton and twin mothers, irrespective of their personal and obstetric characteristics. Large-scale longitudinal research is needed to identify predictors of parenting stress, which may help to develop parenting stress reducing interventions. The acknowledgement and support of an adequate coparenting relationship quality by health care professionals might be an important factor to include in such interventions., (Copyright © 2017 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2018
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32. Chikungunya virus infection in Aruba: Diagnosis, clinical features and predictors of post-chikungunya chronic polyarthralgia.
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Huits R, De Kort J, Van Den Berg R, Chong L, Tsoumanis A, Eggermont K, Bartholomeeusen K, Ariën KK, Jacobs J, Van Esbroeck M, Bottieau E, and Cnops L
- Subjects
- Adolescent, Adult, Antibodies, Viral blood, Arthralgia complications, Arthralgia epidemiology, Aruba, Chikungunya Fever epidemiology, Chronic Disease, Cohort Studies, Female, Fluorescent Antibody Technique, Indirect, Genotype, Humans, Immunoglobulin G blood, Joints pathology, Male, Middle Aged, Risk Factors, Surveys and Questionnaires, Treatment Outcome, Young Adult, Arthralgia virology, Chikungunya Fever complications, Chikungunya virus genetics
- Abstract
Background: Chikungunya virus (CHIKV) emerged in Aruba for the first time in 2014. We studied the clinical presentation of acute CHIKV infection and the contribution of serologic and molecular assays to its diagnosis. In a cohort of confirmed CHIKV cases, we analysed the frequency, duration and predictors of post-chikungunya chronic polyarthralgia (pCHIK-CPA), defined as joint pains lasting longer than 6 weeks or longer than 1 year., Methodology: Patient sera obtained within 10 days of symptom onset were tested for CHIKV, using an indirect immunofluorescence test for the detection of CHIKV-specific Immunoglobulin M (IgM) and post-hoc, by reverse-transcription polymerase chain reaction (RT-PCR). CHIKV was isolated from selected samples and genotyped. For confirmed CHIKV cases, clinical data from chart review were complemented by a Telephone survey, conducted 18-24 months after diagnosis. When joint pain was reported, the duration, presence of inflammatory signs, type and number of joints affected, were recorded. Joint involvement was scored according to the 2010 'American College of Rheumatology/ European League Against Rheumatism' criteria for seronegative rheumatoid arthritis (ACR-score). Risk factors for pCHIK-CPA were identified by logistic regression., Principal Findings: Acute CHIKV infection was diagnosed in 269 of 498 sera, by detection of IgM (n = 105), by RT-PCR (n = 59), or by both methods (n = 105). Asian genotype was confirmed in 7 samples. Clinical data were complete for 171 of 248 (69.0%) patients, aged 15 years or older (median 49.4 [35.0-59.6]). The female-to-male ratio was 2.2. The main acute symptoms were arthralgia (94%), fever (85%), myalgia (85%), headache (73%) and rash (63%). In patients with arthralgia (n = 160), pCHIK-CPA longer than 6 weeks was reported by 44% and longer than 1 year by 26% of cases. Inflammatory signs, stiffness, edema and redness were frequent (71%, 39% and 21%, respectively). Joints involved were knees (66%), ankles (50%), fingers (52%), feet (46%), shoulders (36%), elbows (34%), wrists (35%), hips (31%), toes (28.1%) and spine (28.1%). Independent predictors of pCHIK-CPA longer than 1 year were female gender (OR 5.9, 95%-CI [2.1-19.6]); high ACR-score (7.4, [2.7-23.3]), and detection of CHIKV-RNA in serum beyond 7 days of symptom onset (6.4, [1.4-34.1]., Conclusions: We identified 269 CHIKV patients after the first outbreak of Asian genotype CHIKV in Aruba in 2014-2015. RT-PCR yielded 59 (28%) additional CHIKV diagnoses compared to IgM antibody detection alone. Arthralgia, fever and skin rash were the dominant acute phase symptoms. pCHIK-CPA longer than 1 year affected 26% of cases and was predicted by female gender, high ACR-score and CHIKV-RNA detection beyond 7 days of symptom onset.
- Published
- 2018
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33. Efficient Recombinase-Mediated Cassette Exchange in hPSCs to Study the Hepatocyte Lineage Reveals AAVS1 Locus-Mediated Transgene Inhibition.
- Author
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Ordovás L, Boon R, Pistoni M, Chen Y, Wolfs E, Guo W, Sambathkumar R, Bobis-Wozowicz S, Helsen N, Vanhove J, Berckmans P, Cai Q, Vanuytsel K, Eggermont K, Vanslembrouck V, Schmidt BZ, Raitano S, Van Den Bosch L, Nahmias Y, Cathomen T, Struys T, and Verfaillie CM
- Published
- 2018
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34. SOX10 Single Transcription Factor-Based Fast and Efficient Generation of Oligodendrocytes from Human Pluripotent Stem Cells.
- Author
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García-León JA, Kumar M, Boon R, Chau D, One J, Wolfs E, Eggermont K, Berckmans P, Gunhanlar N, de Vrij F, Lendemeijer B, Pavie B, Corthout N, Kushner SA, Dávila JC, Lambrichts I, Hu WS, and Verfaillie CM
- Subjects
- Amyotrophic Lateral Sclerosis genetics, Amyotrophic Lateral Sclerosis therapy, Antigens, Surface genetics, Gene Expression Regulation, Developmental, Humans, Multiple Sclerosis genetics, Multiple Sclerosis pathology, Multiple Sclerosis therapy, Myelin Basic Protein genetics, Neurons pathology, Neurons transplantation, Oligodendroglia cytology, Oligodendroglia transplantation, Pluripotent Stem Cells cytology, Pluripotent Stem Cells transplantation, Transcriptome genetics, Cell Differentiation genetics, Oligodendroglia metabolism, Pluripotent Stem Cells metabolism, SOXE Transcription Factors genetics
- Abstract
Scarce access to primary samples and lack of efficient protocols to generate oligodendrocytes (OLs) from human pluripotent stem cells (hPSCs) are hampering our understanding of OL biology and the development of novel therapies. Here, we demonstrate that overexpression of the transcription factor SOX10 is sufficient to generate surface antigen O4-positive (O4
+ ) and myelin basic protein-positive OLs from hPSCs in only 22 days, including from patients with multiple sclerosis or amyotrophic lateral sclerosis. The SOX10-induced O4+ population resembles primary human OLs at the transcriptome level and can myelinate neurons in vivo. Using in vitro OL-neuron co-cultures, myelination of neurons by OLs can also be demonstrated, which can be adapted to a high-throughput screening format to test the response of pro-myelinating drugs. In conclusion, we provide an approach to generate OLs in a very rapid and efficient manner, which can be used for disease modeling, drug discovery efforts, and potentially for therapeutic OL transplantation., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)- Published
- 2018
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35. Replication of the Zika virus in different iPSC-derived neuronal cells and implications to assess efficacy of antivirals.
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Lanko K, Eggermont K, Patel A, Kaptein S, Delang L, Verfaillie CM, and Neyts J
- Subjects
- Animals, Cell Line, Chlorocebus aethiops, DNA Replication drug effects, Humans, Induced Pluripotent Stem Cells drug effects, Neurons drug effects, Ribavirin pharmacology, Vero Cells, Antiviral Agents pharmacology, Induced Pluripotent Stem Cells virology, Neurons virology, Virus Replication drug effects, Zika Virus drug effects, Zika Virus physiology
- Abstract
Infections with the Zika virus (ZIKV) are responsible for congenital abnormalities and neurological disorders. We here demonstrate that ZIKV productively infects three types of human iPSC (induced pluripotent stem cells)-derived cells from the neural lineage, i.e. cortical and motor neurons as well as astrocytes. ZIKV infection results in all three cell types in the production of infectious virus particles and induces cytopathic effects (CPE). In cortical and motor neurons, an Asian isolate (PRVABC59) produced roughly 10-fold more virus than the prototypic African strain (MR766 strain). Viral replication and CPE is efficiently inhibited by the nucleoside polymerase inhibitor 7-deaza-2'-C-methyladenosine (7DMA). However, ribavirin and favipiravir, two molecules that inhibit ZIKV replication in Vero cells, did not inhibit ZIKV replication in the neuronal cells. These results highlight the need to assess the potential antiviral activity of novel ZIKV inhibitors in stem cell derived neuronal cultures., (Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2017
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36. Needs of fathers during labour and childbirth: A cross-sectional study.
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Eggermont K, Beeckman D, Van Hecke A, Delbaere I, and Verhaeghe S
- Subjects
- Adult, Belgium, Cross-Sectional Studies, Female, Humans, Male, Pregnancy, Socioeconomic Factors, Surveys and Questionnaires, Emotions, Fathers psychology, Parturition psychology, Sexual Partners psychology, Spouses psychology
- Abstract
Fathers play an important role in the childbearing process, but are sometimes sidelined by midwives. The objectives were: identify fathers' needs during the labor and childbirth process; determine if their needs were met by midwives; and identify variables influencing these needs. The questionnaire was designed based on a systematic literature search and validated by a multistage consensus method. Data were collected during a cross-sectional study in two maternity wards in Belgium, where a medical-led model is used. Fathers present during natural childbirth were recruited via consecutive sampling. Based on multivariate analyses, fathers with a higher education level and multiparous fathers needed less information about the process of birth compared to less educated fathers (p<0.05; OR=4.08; 95% CI=1.02-16.31) or first-time fathers (p<0.001; OR=0.04; 95% CI=0.01-0.18). For multiparous fathers, a tour of the delivery room was less important than for primiparous fathers (p=0.005; OR=0.14; 95% CI=0.03-0.54). Married fathers needed less information on how to support their partners physically (p<0.005; OR=0.18; 95% CI=0.06-0.59) and emotionally (p=0.01; OR=0.24; 95% CI=0.08-0.72) compared to cohabiting fathers. Information needs are more important to fathers compared to needs focusing on the birth experience or their involvement. Socio-demographic variables like educational level, parity, and marital status were associated with fathers' needs. Midwives need to be aware of fathers' needs during the birth process and to fulfill these needs appropriately., (Copyright © 2016 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2017
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37. H3K27me3 Does Not Orchestrate the Expression of Lineage-Specific Markers in hESC-Derived Hepatocytes In Vitro.
- Author
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Vanhove J, Pistoni M, Welters M, Eggermont K, Vanslembrouck V, Helsen N, Boon R, Najimi M, Sokal E, Collas P, Voncken JW, and Verfaillie CM
- Subjects
- Cell Differentiation drug effects, Cell Differentiation genetics, Dimethyl Sulfoxide pharmacology, Enhancer of Zeste Homolog 2 Protein metabolism, Gene Expression Regulation drug effects, Hepatocytes drug effects, Humans, Methylation, Regulatory Sequences, Nucleic Acid genetics, Transcription, Genetic drug effects, Biomarkers metabolism, Cell Lineage drug effects, Cell Lineage genetics, Hepatocytes cytology, Hepatocytes metabolism, Histones metabolism, Human Embryonic Stem Cells cytology, Lysine metabolism
- Abstract
Although pluripotent stem cells can be differentiated into the hepatocyte lineages, such cells retain an immature phenotype. As the chromatin state of regulatory regions controls spatiotemporal gene expression during development, we evaluated changes in epigenetic histone marks in lineage-specific genes throughout in vitro hepatocyte differentiation from human embryonic stem cells (hESCs). Active acetylation and methylation marks at promoters and enhancers correlated with progressive changes in gene expression. However, repression-associated H3K27me3 marks at these control regions showed an inverse correlation with gene repression during transition from hepatic endoderm to a hepatocyte-like state. Inhibitor of Enhancer of Zeste Homolog 2 (EZH2) reduced H3K27me3 decoration but did not improve hepatocyte maturation. Thus, H3K27me3 at regulatory regions does not regulate transcription and appears dispensable for hepatocyte lineage differentiation of hESCs in vitro., (Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.)
- Published
- 2016
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38. Efficient Recombinase-Mediated Cassette Exchange in hPSCs to Study the Hepatocyte Lineage Reveals AAVS1 Locus-Mediated Transgene Inhibition.
- Author
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Ordovás L, Boon R, Pistoni M, Chen Y, Wolfs E, Guo W, Sambathkumar R, Bobis-Wozowicz S, Helsen N, Vanhove J, Berckmans P, Cai Q, Vanuytsel K, Eggermont K, Vanslembrouck V, Schmidt BZ, Raitano S, Van Den Bosch L, Nahmias Y, Cathomen T, Struys T, and Verfaillie CM
- Subjects
- Cells, Cultured, DNA Methylation, Dependovirus genetics, Embryonic Stem Cells cytology, Gene Silencing, Genetic Loci, Hepatocytes metabolism, Humans, Induced Pluripotent Stem Cells cytology, Recombinases genetics, Embryonic Stem Cells metabolism, Gene Targeting methods, Hepatocytes cytology, Induced Pluripotent Stem Cells metabolism, Recombinases metabolism, Transgenes
- Abstract
Tools for rapid and efficient transgenesis in "safe harbor" loci in an isogenic context remain important to exploit the possibilities of human pluripotent stem cells (hPSCs). We created hPSC master cell lines suitable for FLPe recombinase-mediated cassette exchange (RMCE) in the AAVS1 locus that allow generation of transgenic lines within 15 days with 100% efficiency and without random integrations. Using RMCE, we successfully incorporated several transgenes useful for lineage identification, cell toxicity studies, and gene overexpression to study the hepatocyte lineage. However, we observed unexpected and variable transgene expression inhibition in vitro, due to DNA methylation and other unknown mechanisms, both in undifferentiated hESC and differentiating hepatocytes. Therefore, the AAVS1 locus cannot be considered a universally safe harbor locus for reliable transgene expression in vitro, and using it for transgenesis in hPSC will require careful assessment of the function of individual transgenes., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2015
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39. Hematopoietic stem/progenitor cells directly contribute to arteriosclerotic progression via integrin β2.
- Author
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Wang X, Gao M, Schouteden S, Roebroek A, Eggermont K, van Veldhoven PP, Liu G, Peters T, Scharffetter-Kochanek K, Verfaillie CM, and Feng Y
- Subjects
- Animals, Arteriosclerosis pathology, Hematopoietic Stem Cells pathology, Hypercholesterolemia metabolism, Hypercholesterolemia pathology, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Mice, Knockout, Arteriosclerosis metabolism, CD18 Antigens biosynthesis, Disease Progression, Hematopoietic Stem Cells metabolism
- Abstract
Recent studies described the association between hematopoietic stem/progenitor cell (HSPC) expansion in the bone marrow (BM), leukocytosis in the peripheral blood, and accelerated atherosclerosis. We hypothesized that circulating HSPC may home to inflamed vessels, where they might contribute to inflammation and neointima formation. We demonstrated that Lin(-) Sca-1(+) cKit(+) (LSK cells) in BM and peripheral blood of LDLr(-/-) mice on high fat diet expressed significantly more integrin β2 , which was responsible for LSK cell adhesion and migration toward ICAM-1 in vitro, and homing to injured arteries in vivo, all of which were blocked with an anti-CD18 blocking antibody. When homed LSK cells were isolated from ligated artery and injected to irradiated recipients, they resulted in BM reconstitution. Injection of CD18(+/+) LSK cells to immunodeficient Balb/C Rag2(-) ɣC(-/-) recipients resulted in more severe inflammation and reinforced neointima formation in the ligated carotid artery, compared to mice injected with PBS and CD18(-/-) LSK cells. Hypercholesterolemia stimulated ERK phosphorylation (pERK) in LSK cells of LDLr(-/-) mice in vivo. Blockade of pERK reduced ARF1 expression, leading to decreased integrin β2 function on HSPC. In addition, integrin β2 function could be regulated via ERK-independent LRP1 pathway. Integrin β2 expression on HSPC is regulated by hypercholesterolemia, specifically LDL, in pERK-dependent and -independent manners, leading to increased homing and localization of HSPC to injured arteries, which is highly correlated with arteriosclerosis., (© 2014 The Authors. STEM CELLS Published by Wiley Periodicals, Inc. on behalf AlphaMed Press.)
- Published
- 2015
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40. Controlling and monitoring stem cell safety in vivo in an experimental rodent model.
- Author
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Leten C, Roobrouck VD, Struys T, Burns TC, Dresselaers T, Vande Velde G, Santermans J, Lo Nigro A, Ibrahimi A, Gijsbers R, Eggermont K, Lambrichts I, Verfaillie CM, and Himmelreich U
- Subjects
- Animals, Brain metabolism, Cell Line, Green Fluorescent Proteins metabolism, Luciferases, Firefly metabolism, Magnetic Resonance Imaging, Mice, Models, Animal, Octamer Transcription Factor-3 metabolism, Rabbits, Rats, Ganciclovir metabolism, Stem Cells cytology
- Abstract
Adult stem cells have been investigated increasingly over the past years for multiple applications. Although they have a more favorable safety profile compared to pluripotent stem cells, they are still capable of self-renewal and differentiate into several cell types. We investigated the behavior of Oct4-positive (Oct4(+)) and Oct4-negative (Oct4(-) ) murine or rat bone marrow (BM)-derived stem cells in the healthy brain of syngeneic mice and rats. Engraftment of mouse and rat Oct4-positive BM-derived hypoblast-like stem cells (m/rOct4(+) BM-HypoSCs) resulted in yolk-sac tumor formation in the healthy brain which was monitored longitudinally using magnetic resonance imaging (MRI) and bioluminescence imaging (BLI). Contrast enhanced MRI confirmed the disruption of the blood brain barrier. In contrast, m/r Oct4-negative BM-derived multipotent adult progenitor cells (m/rOct4(-) BM-MAPCs) did not result in mass formation after engraftment into the brain. mOct4(+) BM-HypoSCs and mOct4(-) BM-MAPCs were transduced to express enhanced green fluorescent protein, firefly luciferase (fLuc), and herpes simplex virus-thymidine kinase to follow up suicide gene expression as a potential "safety switch" for tumor-forming stem cells by multimodal imaging. Both cell lines were eradicated efficiently in vivo by ganciclovir administration indicating successful suicide gene expression in vivo, as assessed by MRI, BLI, and histology. The use of suicide genes to prevent tumor formation is in particular of interest for therapeutic approaches where stem cells are used as vehicles to deliver therapeutic genes., (© 2014 AlphaMed Press.)
- Published
- 2014
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41. Regulation of high-density lipoprotein on hematopoietic stem/progenitor cells in atherosclerosis requires scavenger receptor type BI expression.
- Author
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Gao M, Zhao D, Schouteden S, Sorci-Thomas MG, Van Veldhoven PP, Eggermont K, Liu G, Verfaillie CM, and Feng Y
- Subjects
- Acetylcysteine pharmacology, Acetylcysteine therapeutic use, Animals, Apolipoprotein A-I pharmacology, Atherosclerosis blood, Atherosclerosis prevention & control, Bone Marrow Transplantation, Cell Division drug effects, Diet, Atherogenic adverse effects, Disease Progression, Hematopoietic Stem Cells drug effects, Hematopoietic Stem Cells pathology, Humans, Hypercholesterolemia complications, Hypercholesterolemia genetics, Leukocytosis etiology, MAP Kinase Signaling System, Mice, Mice, Inbred C57BL, Mice, Knockout, Phosphorylation, Protein Processing, Post-Translational, Proto-Oncogene Proteins c-akt metabolism, Radiation Chimera, Reactive Oxygen Species metabolism, Receptors, LDL deficiency, Receptors, LDL genetics, Scavenger Receptors, Class B deficiency, Scavenger Receptors, Class B genetics, Atherosclerosis etiology, Hematopoietic Stem Cells metabolism, Lipoproteins, HDL metabolism, Scavenger Receptors, Class B blood, Scavenger Receptors, Class B physiology
- Abstract
Objective: Recently, we demonstrated that scavenger receptor type BI (SR-BI), a high-density lipoprotein (HDL) receptor, was expressed on murine hematopoietic stem/progenitor cells (HSPC) and infusion of reconstituted HDL and purified human apolipoprotein A-I (apoA-I) suppressed HSPC proliferation. We hypothesized that SR-B1 expression is required for the observed antiproliferative effects of HDL on HSPC., Approach and Results: SR-BI-deficient (SR-BI(-/-)) mice and wild-type controls were fed on chow or high-fat diet (HFD) for 8 to 10 weeks. Under chow diet, a significant increase in Lin(-) Sca1(+) cKit(+) cells (LSK cells, so-called HSPC) was found in the bone marrow of SR-BI(-/-) mice when compared with wild-type mice. HFD induced a further expansion of CD150(+)CD48(-) LSK cells (HSC), HSPC, and granulocyte monocyte progenitors in SR-BI(-/-) mice. Injection of reactive oxygen species inhibitor N-acetylcysteine attenuated HFD-induced HSPC expansion, leukocytosis, and atherosclerosis in SR-BI(-/-) mice. ApoA-I infusion inhibited HSPC cell proliferation, Akt phosphorylation and reactive oxygen species production in HSPC and plaque progression in low-density lipoprotein receptor knockout (LDLr(-/-)) apoA-I(-/-) mice on HFD but had no effect on SR-BI(-/-) mice on HFD. Transplantation of SR-BI(-/-) bone marrow cells into irradiated LDLr(-/-) recipients resulted in enhanced white blood cells reconstitution, inflammatory cell production, and plaque development. In patients with coronary heart disease, HDL levels were negatively correlated with white blood cells count and HSPC frequency in the peripheral blood. By flow cytometry, SR-BI expression was detected on human HSPC., Conclusions: SR-BI plays a critical role in the HDL-mediated regulation HSPC proliferation and differentiation, which is associated with atherosclerosis progression., (© 2014 American Heart Association, Inc.)
- Published
- 2014
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42. NKX2-1 activation by SMAD2 signaling after definitive endoderm differentiation in human embryonic stem cell.
- Author
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Li Y, Eggermont K, Vanslembrouck V, and Verfaillie CM
- Subjects
- Activins physiology, Binding Sites, Bone Morphogenetic Proteins physiology, Cell Line, Gene Expression Regulation, Growth Differentiation Factors physiology, Humans, Nuclear Proteins genetics, Phosphorylation, Promoter Regions, Genetic, Protein Binding, Protein Processing, Post-Translational, Respiratory System cytology, Signal Transduction, Thyroid Nuclear Factor 1, Transcription Factors genetics, Cell Differentiation, Embryonic Stem Cells physiology, Endoderm cytology, Nuclear Proteins metabolism, Smad2 Protein metabolism, Transcription Factors metabolism
- Abstract
Expression of NKX2-1 is required to specify definitive endoderm to respiratory endoderm. However, the transcriptional regulation of NKX2-1 is not fully understood. Here we demonstrate that aside from specifying undifferentiated human embryonic stem cell (hESC) to definitive endoderm, high concentrations of Activin-A are also necessary and sufficient to induce hESC-derived definitive endodermal progeny to a FOXA2/NKX2-1/GATA6/PAX9 positive respiratory epithelial fate. Activin-A directly mediates the induction of NKX2-1 by interacting with ALK4, leading to phosphorylation of SMAD2, which binds directly to the NKX2-1 promoter and activates its expression. Activin-A can be replaced by GDF11 but not transforming growth factor β1. Addition of Wnt3a, SHH, FGF2, or BMP4 failed to induce NKX2-1. These results suggest that direct binding of Activin-A-responsive SMAD2 to the NKX2-1 promoter plays essential role during respiratory endoderm specification.
- Published
- 2013
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43. MAPC culture conditions support the derivation of cells with nascent hypoblast features from bone marrow and blastocysts.
- Author
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Lo Nigro A, Geraerts M, Notelaers T, Roobrouck VD, Muijtjens M, Eggermont K, Subramanian K, Ulloa-Montoya F, Park Y, Owens J, Burns TC, Low W, Sharma S, Sohni A, Crabbe A, Pauwelyn K, Roelandt P, Agirre X, Prosper F, O'Brien TD, Zwijsen A, Hu WS, Binas B, and Verfaillie CM
- Subjects
- Animals, Blastocyst physiology, Cell Culture Techniques methods, Cell Differentiation genetics, Cells, Cultured, Developmental Biology methods, Gene Expression genetics, Gene Expression physiology, Germ Layers physiology, Phenotype, Rats, Stem Cells cytology, Stem Cells physiology, Blastocyst cytology, Bone Marrow physiology, Cell Differentiation physiology, Germ Layers cytology
- Published
- 2012
- Full Text
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44. Zic3 induces conversion of human fibroblasts to stable neural progenitor-like cells.
- Author
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Kumar A, Declercq J, Eggermont K, Agirre X, Prosper F, and Verfaillie CM
- Subjects
- Animals, Cell Line, Embryonic Stem Cells cytology, Embryonic Stem Cells metabolism, Gene Expression Regulation, Homeodomain Proteins genetics, Homeodomain Proteins metabolism, Humans, Kruppel-Like Factor 4, Kruppel-Like Transcription Factors genetics, Kruppel-Like Transcription Factors metabolism, Mice, Mice, SCID, Neural Stem Cells metabolism, Octamer Transcription Factor-3 genetics, Octamer Transcription Factor-3 metabolism, RNA, Messenger genetics, RNA, Messenger metabolism, SOXB1 Transcription Factors genetics, SOXB1 Transcription Factors metabolism, Transcription Factors genetics, Transcription Factors metabolism, Transduction, Genetic, Transgenes genetics, Cell Differentiation, Fibroblasts cytology, Fibroblasts metabolism, Neural Stem Cells cytology
- Published
- 2012
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45. Lentiviral vectors mediate efficient and stable gene transfer in adult neural stem cells in vivo.
- Author
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Geraerts M, Eggermont K, Hernandez-Acosta P, Garcia-Verdugo JM, Baekelandt V, and Debyser Z
- Subjects
- Animals, Astrocytes cytology, Astrocytes virology, Cell Movement physiology, Cells, Cultured, Ependyma cytology, Ependyma virology, Female, Genes, Reporter, Genetic Vectors administration & dosage, Genetic Vectors genetics, Green Fluorescent Proteins biosynthesis, Green Fluorescent Proteins genetics, Humans, Injections, Intraventricular, Interneurons cytology, Lateral Ventricles cytology, Lateral Ventricles virology, Lentivirus genetics, Mice, Mice, Inbred C57BL, Olfactory Bulb cytology, Olfactory Bulb metabolism, Recombinant Proteins analysis, Stem Cells cytology, Stem Cells virology, Time Factors, Transfection methods, Gene Transfer Techniques, Genetic Vectors physiology, Interneurons physiology, Lentivirus physiology, Stem Cells physiology
- Abstract
Modulation of adult neurogenesis may offer new therapeutic strategies for various brain disorders. In the adult mammalian brain the subventricular zone (SVZ) of the lateral ventricle is a region of continuous neurogenesis. Lentiviral vectors stably integrate into dividing and nondividing cells, in contrast to retroviral vectors, which integrate only into dividing cells. We compared their potential for gene transfer into both quiescent and slowly dividing stem cells as well as into more rapidly dividing progenitor cells. In contrast to retroviral vectors, stereotactic injection of lentiviral vectors into the SVZ of adult mice resulted in efficient and long-term marker gene expression in cells with characteristics of both immature type B cells and migrating precursor cells. After migration along the rostral migratory stream and differentiation, the number of enhanced green fluorescent protein (eGFP)-expressing granular and periglomerular interneurons increased over time in the ipsilateral olfactory bulb. Moreover, the number of eGFP-labeled neuronal progenitor cells in the SVZ increased over time. By intraventricular injection of lentiviral vectors we could restrict gene transfer to ependymal cells and type B astroglial-like stem cells. In conclusion, lentiviral vectors surpass retroviral vectors in efficient long-term in vivo marking of subventricular zone stem cells for basic research and therapeutic applications.
- Published
- 2006
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46. Lentiviral vector-mediated delivery of short hairpin RNA results in persistent knockdown of gene expression in mouse brain.
- Author
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Van den Haute C, Eggermont K, Nuttin B, Debyser Z, and Baekelandt V
- Subjects
- Animals, Base Sequence, Central Nervous System Neoplasms genetics, Central Nervous System Neoplasms therapy, Down-Regulation, Green Fluorescent Proteins, HIV-1 genetics, Luminescent Proteins biosynthesis, Luminescent Proteins genetics, Mice, Mice, Inbred C57BL, Molecular Sequence Data, Reverse Transcriptase Polymerase Chain Reaction, Brain, Gene Expression Regulation, Genetic Therapy methods, Genetic Vectors, Lentivirus genetics, RNA Interference
- Abstract
RNA interference (RNAi) is an evolutionarily conserved mechanism of posttranscriptional gene-specific silencing. For in vivo applications, RNAi has been hampered until recently by inefficient delivery methods and by the transient nature of the gene suppression. Lentiviral vectors (LVs) hold great promise for gene therapeutic applications, pharmaceutical target validation, and functional genomics because stable gene transfer is mediated both in dividing and nondividing cells. We have used a lentiviral vector-based system for RNAi. We produced human immunodeficiency virus type 1-derived LVs encoding a short hairpin RNA specific for enhanced green fluorescent protein (EGFP) mRNA that were capable of inhibiting EGFP expression in mammalian cells. EGFP knockdown persisted after multiple passages of the cells. Of particular interest, our RNAi LVs were equally effective in suppression and prevention of EGFP expression after stereotactic injection in adult mouse brain. Therefore, we believe that the use of LVs for stable RNAi in brain will become a powerful aid to probe gene function in vivo and for gene therapy of diseases of the central nervous system.
- Published
- 2003
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47. The Arabidopsis mutant iop1 exhibits induced over-expression of the plant defensin gene PDF1.2 and enhanced pathogen resistance.
- Author
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Penninckx IA, Eggermont K, Schenk PM, Van den Ackerveken G, Cammue BP, and Thomma BP
- Abstract
SUMMARY Jasmonate and ethylene are concomitantly involved in the induction of the Arabidopsis plant defensin gene PDF1.2. To define genes in the signal transduction pathway leading to the induction of PDF1.2, we screened for mutants with induced over-expression of a beta-glucuronidase reporter, under the control of the PDF1.2 promoter. One mutant, iop1 (induced over-expressor of PDF1.2) produced small plants that showed induced over-expression of the pathogenesis-related genes PR-3, PR-4 and PR-1,2 (PDF1.2), combined with a down-regulated induction of PR-1 upon pathogen inoculation. The iop1 mutant showed enhanced resistance to a number of necrotrophic pathogens.
- Published
- 2003
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48. Characterization of lentiviral vector-mediated gene transfer in adult mouse brain.
- Author
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Baekelandt V, Claeys A, Eggermont K, Lauwers E, De Strooper B, Nuttin B, and Debyser Z
- Subjects
- Animals, Apoptosis, Blotting, Western, Brain pathology, Cell Division, Genetic Vectors, Green Fluorescent Proteins, Hepatitis B Virus, Woodchuck genetics, Hippocampus metabolism, Luminescent Proteins genetics, Luminescent Proteins metabolism, Mice, Mice, Inbred C57BL, Mice, SCID, Microscopy, Confocal, Microscopy, Fluorescence, Neuroglia pathology, Neurons pathology, Plasmids metabolism, Time Factors, Transcription, Genetic, Transgenes, Brain metabolism, Gene Transfer Techniques, Lentivirus genetics
- Abstract
Lentiviral vectors are promising tools for gene transfer into the central nervous system. We have characterized in detail transduction with human immunodeficiency virus type 1 (HIV-1)-derived vectors encoding enhanced green fluorescent protein (eGFP) in the adult mouse brain. Different brain regions such as the striatum, hippocampus, and the lateral ventricle were targeted. The eGFP protein was transported anterogradely in the nigrostriatal pathway, but we have found no evidence of transport of the lentiviral vector particle. The performance levels of the different generations of packaging and transfer plasmid were compared. Omission of the accessory genes from the packaging plasmid resulted in a modest decrease in transgene expression. Inclusion of the woodchuck hepatitis posttranscriptional regulatory element, on the one hand, and the central polypurine tract and termination sequences, on the other hand, in the transfer vector each resulted in a 4- to 5-fold increase in transgene expression levels. Combination of both elements enhanced expression levels more than the sum of the individual components, suggesting a synergistic effect. In the serum of mice injected with lentiviral vectors a humoral response to vector proteins was detected, but this did not compromise transgene expression. Immune response to the transgene was found only in a minority of the animals.
- Published
- 2002
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49. Esa1, an Arabidopsis mutant with enhanced susceptibility to a range of necrotrophic fungal pathogens, shows a distorted induction of defense responses by reactive oxygen generating compounds.
- Author
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Tierens KF, Thomma BP, Bari RP, Garmier M, Eggermont K, Brouwer M, Penninckx IA, Broekaert WF, and Cammue BP
- Subjects
- Arabidopsis genetics, Arabidopsis metabolism, Cyclopentanes pharmacology, Ethylenes pharmacology, Gene Expression Regulation, Plant drug effects, Immunity, Innate drug effects, Indoles pharmacology, Mutation, Nitrobenzoates pharmacology, Oxylipins, Paraquat pharmacology, Plant Diseases microbiology, Plant Extracts metabolism, Plant Proteins genetics, Plant Proteins metabolism, Salicylates pharmacology, Sesquiterpenes, Terpenes, Thiazoles pharmacology, Phytoalexins, Alternaria pathogenicity, Arabidopsis microbiology, Defensins, Plant Diseases genetics, Reactive Oxygen Species metabolism
- Abstract
An Arabidopsis thaliana mutant, esa1, that shows enhanced susceptibility to the necrotrophic pathogens Alternaria brassicicola, Botrytis cinerea and Plectosphaerella cucumerina, but has wild-type levels of resistance to the biotrophic pathogens Pseudomonas syringae pv. tomato and Peronospora parasitica. The enhanced susceptibility towards necrotrophic pathogens correlated with a delayed induction of phytoalexin accumulation and delayed induction of the plant defensin gene PDF1.2 upon inoculation with pathogens. Two reactive oxygen generating compounds, paraquat and acifluorfen, were found to cause induction of both phytoalexin accumulation and PDF1.2 expression in wild-type plants, but this induction was almost completely abolished in esa1. This finding suggests that esa1 may somehow be involved in transduction of signals generated by reactive oxygen species.
- Published
- 2002
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- View/download PDF
50. Deficiency in phytoalexin production causes enhanced susceptibility of Arabidopsis thaliana to the fungus Alternaria brassicicola.
- Author
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Thomma BP, Nelissen I, Eggermont K, and Broekaert WF
- Subjects
- Anti-Infective Agents metabolism, Antifungal Agents pharmacology, Arabidopsis genetics, Arabidopsis microbiology, Botrytis growth & development, Cyclopentanes pharmacology, Disease Susceptibility, Ethylenes pharmacology, Gene Expression Regulation, Plant, Indoles metabolism, Mutation, Oxylipins, Plant Growth Regulators pharmacology, Plant Proteins genetics, Salicylic Acid pharmacology, Sesquiterpenes, Terpenes, Thiazoles metabolism, Phytoalexins, Alternaria growth & development, Arabidopsis metabolism, Defensins, Plant Diseases microbiology, Plant Extracts metabolism
- Abstract
The phytoalexin-deficient Arabidopsis mutant pad3-1, which is affected in the production of the indole-type phytoalexin camalexin, has previously been shown not to display altered susceptibility to either the bacterium Pseudomonas syringae (Glazebrook & Ausubel 1994; Proc. Natl. Acad. Sci. USA, 91: 8955-8959) or the biotrophic fungi Peronospora parasitica (Glazebrook et al. 1997; Genetics, 146: 381-392) and Erysiphe orontii (Reuber et al. 1998; Plant J. 16: 473-485). We now show that this mutant is markedly more susceptible than its wild-type parental line to infection by the necrotrophic fungus Alternaria brassicicola, but not to Botrytis cinerea. A strong camalexin response was elicited in wild-type plants inoculated with either Alternaria brassicicola or Botrytis cinerea, whereas no camalexin could be detected in pad3-1 challenged with these fungi. Hence, PAD3 appears to be a key determinant in resistance to at least A. brassicicola. The induction of salicylate-dependent and jasmonate/ethylene-dependent defense genes was not reduced in Alternaria-challenged pad3-1 plants compared to similarly treated wild-type plants. Camalexin production could not be triggered by exogenous application of either salicylate, ethylene or jasmonate and was not, or not strongly, reduced in mutants with defects in perception of these defense-related signal molecules. Camalexin-production appears to be controlled by a pathway that exhibits little cross-talk with salicylate-, ethylene- and jasmonate-dependent signalling events.
- Published
- 1999
- Full Text
- View/download PDF
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