347 research outputs found
N011 Culture et délivrance au niveau du tissu cardiaque de cardiomyocytes issus de cellules souches embryonnaires humaines au moyen de matrices tridimensionelles poreuses à base de polysaccharides
Un intĂ©rĂȘt particulier a Ă©tĂ© portĂ© ces derniĂšres annĂ©es Ă la thĂ©rapie cellulaire rĂ©paratrice cardiaque. Les cellules souches embryonnaires humaines (hES) sont une source prouvĂ©e de cardiomyocytes et les premiĂšres donnĂ©es in vivo suggĂšrent leurs capacitĂ©s fonctionnelles Ă type dâeffet pacemaker ou rĂ©paratrices dâinfarctus du myocarde. Nous avons Ă©tudiĂ© un mode de dĂ©livrance des cellules hES dans le tissu cardiaque basĂ© sur une matrice 3D servant de support Ă la fois pour la culture des cellules et pour leur implantation au contact du myocarde.Des matrices poreuses de polysaccharides (pullulane et dextrane) ont Ă©tĂ© prĂ©parĂ©es par rĂ©ticulation chimique permettant de rĂ©aliser des films avec des pores de 100 Ă 200 microns. Les matrices ont Ă©tĂ© recouvertes de diffĂ©rentes protĂ©ines; les cellules hES indiffĂ©renciĂ©es ont Ă©tĂ© cultivĂ©es sur fibroblastes murins, en milieu supplĂ©mentĂ© avec du sĂ©rum knock-out et du FGF2. Dans une premiĂšre partie in vitro, nous avons mis en Ă©vidence par q-RT-PCR, observation microscopique et imagerie confocale, la diffĂ©renciation en cardiomyocytes de cellules hES directement cultivĂ©es dans les matrices en prĂ©sence dâun milieu inducteur de diffĂ©rentiation; les matrices permettaient aussi la culture, lâexpansion et la survie Ă long terme de parties battantes obtenues Ă partir de corps embryoĂŻdes issus dâhES et isolĂ©es manuellement. Nous avons ensuite Ă©tudiĂ© le devenir des cellules hES dans un modĂšle de lĂ©sions cardiaques par dĂ©pĂŽt de films poreux cellularisĂ©s sur les cĆurs infarcis de souris NOD SCID. Lâidentification est confirmĂ©e pour les cardiomyocytes issus dâES dâune lignĂ©e de cellules hES H9 GFP+ ainsi que dâune lignĂ©e de cellules hES dans laquelle lâexpression de la GFP est sous contrĂŽle dâun promoteur spĂ©cifique du tissu cardiaque, Nkx2.5. Nous avons ainsi mis en Ă©vidence la migration des cellules ES Ă diffĂ©rents stades de diffĂ©renciation Ă partir des matrices 3D vers les souris NOD SCID ainsi que leur diffĂ©renciation en cardiomyocytes. Les donnĂ©es de PCR quantitative sur la base du transgĂšne GFP mettent en Ă©vidence une meilleure survie des ES dĂ©livrĂ©es par lâintermĂ©diaire des matrices 3D en comparaison avec une administration directe. Une Ă©tude fonctionnelle comparative est en cours
Structural insights into Legionella RidL-Vps29 retromer subunit interaction reveal displacement of the regulator TBC1D5
Legionella pneumophila can cause Legionnairesâ disease and replicates intracellularly in a distinct Legionella-containing vacuole (LCV). LCV formation is a complex process that involves a plethora of type IV-secreted effector proteins. The effector RidL binds the Vps29 retromer subunit, blocks retrograde vesicle trafficking, and promotes intracellular bacterial replication. Here, we reveal that the 29-kDa N-terminal domain of RidL (RidL2â281) adopts a âfoot-likeâ fold comprising a protruding ÎČ-hairpin at its âheelâ. The deletion of the ÎČ-hairpin, the exchange to Glu of Ile170 in the ÎČ-hairpin, or Leu152 in Vps29 abolishes the interaction in eukaryotic cells and in vitro. RidL2â281 or RidL displace the Rab7 GTPase-activating protein (GAP) TBC1D5 from the retromer and LCVs, respectively, and TBC1D5 promotes the intracellular growth of L. pneumophila. Thus, the hydrophobic ÎČ-hairpin of RidL is critical for binding of the L. pneumophila effector to the Vps29 retromer subunit and displacement of the regulator TBC1D5
PHIL Accelerator at LAL - Diagnostic status
http://accelconf.web.cern.ch/AccelConf/BIW2010/papers/tupsm100.pdfInternational audienceThe "Photo-Injector at LAL" (PHIL : http://phil.lal.in2p3.fr/) is a new electron beam accelerator at LAL. This accelerator is dedicated to test and characterise electron photo-guns and high-frequency structures for future accelerator projects (like the next generation lepton colliders, CLIC, ILC). This machine has been designed to produce low energy (E<10 MeV), small emittance (epsilon < 10 pi.mm.mrad), high current (charge 2 nC/bunch) electrons bunch at low repetition frequency (frep<10Hz) [1]. The first beam has been obtained on the 4th of November 2009. This paper will describe the current status and the futures developments of the diagnostics devices on this machine
Low Energy Beam Measurements Using PHIL Accelerator at LAL, Comparison with PARMELA Simulations
http://accelconf.web.cern.ch/AccelConf/PAC2011/papers/wep210.pdfInternational audiencePHIL ("PHoÂto-InÂjecÂtor at LAL") is a new elecÂtron beam acÂcelÂerÂaÂtor at LAL. This acÂcelÂerÂaÂtor is dedÂiÂcatÂed to test and charÂacÂterÂize elecÂtron RF-guns and to deÂlivÂer elecÂtron beam to users. This maÂchine has been deÂsigned to proÂduce and charÂacÂterise low enÂerÂgy (E<10 MeV), small emitÂtance (e<10 p.âmm.âmrad), high brilÂliance elecÂtrons bunch at low repÂeÂtiÂtion freÂquenÂcy (n<10Hz). The first beam has been obÂtained on the 4th of NovemÂber 2009. The curÂrent RF-gun testÂed on PHIL is the AlÂphaX gun, a 2.5 cell S-band cavÂiÂty deÂsigned by LAL for the plasÂma acÂcelÂerÂaÂtor studÂies perÂformed at the StrathÂclyde uniÂverÂsiÂty. This paper will preÂsent the first AlÂphaX RF-gun charÂacÂterÂiÂzaÂtions perÂformed at LAL on PHIL acÂcelÂerÂaÂtor, and will show comÂparÂisons beÂtween meaÂsureÂments and PARMELA simÂuÂlaÂtions
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Combined transcriptomic-(1)H NMR metabonomic study reveals yhat monoethylhexyl phthalate stimulates adipogenesis and glyceroneogenesis in human adipocytes
Adipose tissue is a major storage site for lipophilic environmental contaminants. The environmental metabolic disruptor hypothesis postulates that some pollutants can promote obesity or metabolic disorders by activating nuclear receptors involved in the control of energetic homeostasis. In this context, monoethylhexyl phthalate (MEHP) is of particular concern since it was shown to activate the peroxisome proliferator-activated receptor Îł (PPARÎł) in 3T3-L1 murine preadipocytes. In the present work, we used an untargeted, combined transcriptomic-(1)H NMR-based metabonomic approach to describe the overall effect of MEHP on primary cultures of human subcutaneous adipocytes differentiated in vitro. MEHP stimulated rapidly and selectively the expression of genes involved in glyceroneogenesis, enhanced the expression of the cytosolic phosphoenolpyruvate carboxykinase, and reduced fatty acid release. These results demonstrate that MEHP increased glyceroneogenesis and fatty acid reesterification in human adipocytes. A longer treatment with MEHP induced the expression of genes involved in triglycerides uptake, synthesis, and storage; decreased intracellular lactate, glutamine, and other amino acids; increased aspartate and NAD, and resulted in a global increase in triglycerides. Altogether, these results indicate that MEHP promoted the differentiation of human preadipocytes to adipocytes. These mechanisms might contribute to the suspected obesogenic effect of MEHP
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