Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The tg(cyp19a1b-GFP) transgenic zebrafish expresses GFP (green fluorescent protein) under the control of the cyp19a1b gene, encoding brain aromatase. This gene has two major characteristics: (i) it is only expressed in radial glial progenitors in the brain of fish and (ii) it is exquisitely sensitive to estrogens. Based on these properties, we demonstrate that natural or synthetic hormones (alone or in binary mixture), including androgens or progestagens, and industrial chemicals induce a concentration-dependent GFP expression in radial glial progenitors. As GFP expression can be quantified by in vivo imaging, this model presents a very powerful tool to screen and characterize compounds potentially acting as estrogen mimics either directly or after metabolization by the zebrafish embryo. This study also shows that radial glial cells that act as stem cells are direct targets for a large panel of endocrine disruptors, calling for more attention regarding the impact of environmental estrogens and/or certain pharmaceuticals on brain development. Altogether these data identify this in vivo bioassay as an interesting alternative to detect estrogen mimics in hazard and risk assessment perspective.
ISSN: 1932-6203

hal-00877371
https://hal.archives-ouvertes.fr/hal-00877371
https://hal.archives-ouvertes.fr/hal-00877371/document
https://hal.archives-ouvertes.fr/hal-00877371/file/Screening_Estrogenic_Activities-accepted.pdf
DOI : 10.1371/journal.pone.0036069

Éditeur(s) : HAL CCSD
Résumé : International audience
BioEM 2015
Monterey, United States

hal-01164074
https://hal.archives-ouvertes.fr/hal-01164074

Éditeur(s) : HAL CCSD
Résumé : National audience
3rd European Doctoral College on Environment and Health
Rennes, France

hal-01115980
https://hal.archives-ouvertes.fr/hal-01115980

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Due to shallow penetration of millimeter waves (MMW) and convection in liquid medium surrounding cells, the problem of accurate assessment of local MMW heating in in vitro experiments remains unsolved. Conventional dosimetric MMW techniques, such as infrared imaging or fiber optic (FO) sensors, face several inherent limits. Here we propose a methodology for accurate local temperature measurement and subsequent specific absorption rate (SAR) retrieval using microscale thermocouples (TC). SAR was retrieved by fitting the measured initial temperature rise to the numerical solution of an equivalent thermal model. It was found that the accuracy of temperature measurement depends on thermosensor size, that is, the smaller TC, the more accurate the temperature measurement. SAR determined using TC with lead diameters of 25 and 75m demonstrated 98.5% and 80.4% match with computed SAR, respectively. However, both TC provided the same temperature rises in long run (>10min). FO probe failed to measure adequately local heating both for short and long exposures due to the relatively large size of the probe sensor (400m) and time constant (0.6s). Calculated SAR in the cell monolayer was almost two times lower than that in the surrounding liquid. It was shown that the impact of the cell monolayer on heating due to its small thickness (5 to 10m) can be considered as negligible. Moreover, we demonstrated the possibility of accurate measurement of MMW-induced thermal pulses (up to 10 degrees C) using 25m TC. Bioelectromagnetics. 38:11-21, 2017. (c) 2016 Wiley Periodicals, Inc.
ISSN: 0197-8462

hal-01436768
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01436768
DOI : 10.1002/bem.21999
PUBMED : 27571392

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : International audience
Millimetre waves correspond to the range of frequencies located between 30 and 300 GHz. Many applications exist and are emerging in this band, including wireless telecommunications, imaging and monitoring systems. In addition, some of these frequencies are used in therapy in Eastern Europe, suggesting that interactions with the human body are possible. This review aims to summarise current knowledge on interactions between millimetre waves and living matter. Several representative examples from the scientific literature are presented. Then, possible mechanisms of interactions between millimetre waves and biological systems are discussed.
ISSN: 1631-0705

hal-00874362
https://hal.archives-ouvertes.fr/hal-00874362
DOI : 10.1016/j.crhy.2013.02.005

Éditeur(s) : HAL CCSD IOS Press
Résumé : International audience
Cancer is generally conceived as a dedifferentiation process in which quiescent post-mitotic differentiated cells acquire stem-like properties and the capacity to proliferate. This view holds for the initial stages of carcinogenesis but is more questionable for advanced stages when the cells can transdifferentiate into the contractile phenotype associated to migration and metastasis. Singularly from this perspective, the hallmark of the most aggressive cancers would correspond to a genuine differentiation status, even if it is different from the original one. This seeming paradox could help reconciling discrepancies in the literature about the pro-or anti-tumoral functions of candidate molecules involved in cancer and whose actual effects depend on the tumoral grade. These ambiguities which are likely to concern a myriad of molecules and pathways, are illustrated here with the selected examples of chromatin epigenetics and myocardin-related transcription factors, using the human MCF10A and MCF7 breast cancer cells. Self-renewing stem like cells are characterized by a loose chromatin with low levels of the H3K9 trimetylation, but high levels of this mark can also appear in cancer cells acquiring a contractile-type differentiation state associated to metastasis. Similarly, the myocardin-related transcription factor MRTF-A is involved in metastasis and epithelial-mesenchymal transition, whereas this factor is naturally enriched in the quiescent cells which are precisely the most resistant to cancer: cardiomyocytes. These seeming paradoxes reflect the bistable epigenetic landscape of cancer in which dedifferentiated self-renewing and differentiated migrating states are incompatible at the single cell level, though coexisting at the population level. © 2016-IOS Press and the authors. All rights reserved.
ISSN: 0888-6008

hal-01367146
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01367146
DOI : 10.3233/BD-150210
PUBMED : 27177343

Éditeur(s) : HAL CCSD
Résumé : Poster
International audience
BEMS 2013
Thessalonique, Greece

hal-00926890
https://hal.archives-ouvertes.fr/hal-00926890

Éditeur(s) : HAL CCSD
Résumé : International audience
Background In life sciences, there is a growing need for new informatics tools designed to provide automated solutions in order to analyze big amounts of images obtained from high-throughput imaging systems. Among the most widely used assays in neurotoxicity, endocrinology and brain diseases, the neurite outgrowth assay is popular. New method Cell-to-cell quantification of the main morphological features of neurite outgrowth assays remains very challenging. Here, we provide a new pipeline developed on Fiji software for analysis of series of two-dimensional images. It allows the automated analysis of most of these features. Results We tested the accuracy and usefulness of the software by confirming the effects of estradiol and hypoxia on in vitro neuronal differentiation, previously published by different authors with manual analysis methods. With this new method, we highlighted original interesting data. Comparison with existing method(s) The innovation brought by this plugin lies in the fact that it can process multiple images at the same time, in order to obtain: the number of nuclei, the number of neurites, the length of neurites, the number of neurites junctions, the number of neurites branches, the length of each branch, the position of the branch in the image, the angle of each branch, but also the area of each cell and the number of neurites per cell. Conclusions This plugin is easy to use, highly sensitive, and allows the experimenter to acquire ready-to-use data coming from a vast amount of images. © 2016 Elsevier B.V.
Journal of Neuroscience Methods

hal-01367152
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01367152
DOI : 10.1016/j.jneumeth.2016.07.011
PUBMED : 27450924

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Les ondes millimétriques correspondent à la gamme des fréquences comprises entre 30 et 300 GHz. De nombreuses applications existent et émergent actuellement dans ce domaine, notamment en télécommunications, imagerie et surveillance. De plus, certaines de ces fréquences sont utilisées en thérapie en Europe de lʼEst, ce qui suggère que des interactions avec lʼorganisme sont possibles. Cette revue vise à résumer lʼétat des connaissances actuelles sur les interactions ondes millimétriques/matière vivante. Plusieurs exemples représentatifs de la littérature scientifique sont présentés. Enfin, les différents mécanismes potentiellement impliqués dans les effets biologiques des ondes millimétriques seront discutés
Comptes Rendus Physique

hal-00877136
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00877136
DOI : 10.1016/j.crhy.2013.02.005

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Technologies for wireless telecommunication systems using millimeter waves (MMW) will be widely deployed in the near future. Forthcoming applications in this band, especially around 60 GHz, are mainly developed for high data-rate local and body-centric telecommunications. At those frequencies, electromagnetic radiations have a very shallow penetration into biological tissues, making skin keratinocytes, and free nerve endings of the upper dermis the main targets of MMW. Only a few studies assessed the impact of MMW on neuronal cells, and none of them investigated a possible effect on neuronal differentiation. We used a neuron-like cell line (PC12), which undergoes neuronal differentiation when treated with the neuronal growth factor (NGF). PC12 cells were exposed at 60.4 GHz for 24 h, at an incident power density averaged over the cell monolayer of 10 mW/cm2. Using a large scale cell-by-cell analysis based on high-content screening microscopy approach, we assessed potential effects of MMW on PC12 neurite outgrowth and cytoskeleton protein expression. No differences were found in protein expression of the neuronal marker β3-Tubulin nor in internal expression control β-Tubulin. On the other hand, our data showed a slight increase, although insignificant, in neurite outgrowth, induced by MMW exposure. However, experimental controls demonstrated that this increase was related to heating
ISSN: 0304-3940

hal-01281481
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01281481
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01281481/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01281481/file/Effects%20of%2060-GHz%20Millimeter%20Waves%20on%20Neurite.pdf
DOI : 10.1016/j.neulet.2016.02.038

Éditeur(s) : HAL CCSD Royal Society
Résumé : International audience
Maternal Embryonic Leucine zipper Kinase (MELK) was recently shown to be involved in cell division of Xenopus embryo epithelial cells. The cytokinetic furrow of these cells ingresses asymmetrically and is developmentally regulated. Two subpopulations of xMELK, the mMELK (for "mitotic" xMELK) and iMELK ("interphase" xMELK), which differ in their spatial and temporal regulation, are detected in Xenopus embryo. How cells regulate these two xMELK populations is unknown. In this study we show that, in epithelial cells, xMELK is present at a higher concentration at the apical junctional complex, in contrast to mesenchyme-like cells, which have uniform distribution of cortical MELK. Interestingly, mMELK and iMELK also differ by their requirements towards cell-cell contacts to establish their proper cortical localization both in epithelial and mesenchyme-like cells. Receptor for Activated protein Kinase C (RACK1), which we identified as an xMELK partner, co-localizes with xMELK at the tight junction. Moreover, a truncated RACK1 construct interferes with iMELK localization at cell-cell contacts. Collectively, our results suggest that iMELK and RACK1 are present in the same complex and that RACK1 is involved in the specific recruitment of iMELK at the apical junctional complex in epithelial cells of Xenopus embryos.
ISSN: 2046-6390

hal-00874053
https://hal.archives-ouvertes.fr/hal-00874053
https://hal.archives-ouvertes.fr/hal-00874053/document
https://hal.archives-ouvertes.fr/hal-00874053/file/Cell-cycle_dependent-accepted.pdf
DOI : 10.1242/bio.20136080