54 research outputs found
Implication des protéines d'enveloppe d'HERVs dans le développement du placenta : utilisation potentielle comme biomarqueurs de la pré-éclampsie
PrĂšs de 8% du gĂ©nome humain est constituĂ© de sĂ©quences d'origine rĂ©trovirale. Ces sĂ©quences HERV s reprĂ©sentent des vestiges d'intĂ©grations rĂ©trovirales ancestrales et font maintenant partie de notre gĂ©nome. Certaines de ces sĂ©quences sont toujours aptes Ă produire des protĂ©ines typiques aux rĂ©trovirus, telles que les protĂ©ines de l'enveloppe. La prĂ©sence des HERVs dans le gĂ©nome humain est associĂ©e Ă divers phĂ©nomĂšnes biologiques. En effet, il a Ă©tĂ© dĂ©montrĂ© que deux protĂ©ines d'enveloppe appartenant Ă des sĂ©quences d'HERV, soit la Syncytine 1 et Syncytine 2, participent au dĂ©veloppement du placenta, en provoquant des Ă©vĂ©nements de fusion cellulaire entre les cellules cytotrophoblastiques du placenta, permettant la formation du syncytiotrophoblaste. Cependant, deux autres protĂ©ines d'enveloppe d'HERVs ont Ă©tĂ© rĂ©cemment identifiĂ©es et suscitent un intĂ©rĂȘt particulier. Il s'agit de EnvP(b), une protĂ©ine fusogĂ©nique mais ubiquitaire et, EnvV, dont l'expression est spĂ©cifique au placenta. La prĂ©sente Ă©tude visait d'abord Ă caractĂ©riser les transcrits de ces protĂ©ines et approfondir notre connaissance du rĂŽle suggĂ©rĂ© dans les Ă©vĂ©nements fusogĂ©niques des cellules trophoblastiques. Nos travaux ont dĂ©montrĂ© que, bien que possĂ©dant chacune un transcrit et une rĂ©gulation transciptionnelle similaires aux deux Syncytines 1 et 2, EnvP(b) et EnvV ne semblent pas ĂȘtre indispensables lors des Ă©vĂ©nements fusogĂ©niques des cytotrophoblastes. La Syncytine 1 et 2 restent alors les deux seules protĂ©ines d'enveloppe d'HERVs connues Ă ce jour, impliquĂ©es dans ce processus. Ainsi, dans un second volet, nous voulions vĂ©rifier si une altĂ©ration de l'expression de ces deux gĂšnes env corrĂ©lait avec un dĂ©faut de fusion des trophoblastes humains et qui plus est, avec les symptĂŽmes de la prĂ©-Ă©clampsie (PE). Nos rĂ©sultats ont dĂ©montrĂ© hors de tout doute, que l'expression de la Syncytine 1 et 2 est altĂ©rĂ©e suivant la condition PE, induisant probablement la diminution de la fusion cellulaire des cytotrophoblastes, laquelle est observĂ©e dans des cas de prĂ©-Ă©clampsie. Cette altĂ©ration fusogĂ©nique, dont les consĂ©quences conduiraient Ă un dysfonctionnement du placenta et donc Ă la condition « prĂ©Ă©clampsie » aurait donc pour origine un dĂ©faut en terme d'expression de ces deux protĂ©ines d'enveloppe. ComplĂ©tant un dernier volet, nous voulions Ă©tudier et Ă©lucider les mĂ©canismes faisant intervenir les exosomes cytotrophoblastiques. L'abondance des protĂ©ines d'enveloppe Syncytine 1 et 2 au sein de ces exosomes, a pour la premiĂšre fois clairement Ă©tĂ© mise en Ă©vidence et, un rĂŽle dans l'adressage et le transfert d'information visant une cellule cible de la couche syncytiale leur a Ă©tĂ© fortement suggĂ©rĂ©. Finalement, l'Ă©tude de la composition de ces exosomes dans la circulation maternelle de patientes prĂ©-Ă©clamptiques nous a permis de mettre en Ă©vidence une dĂ©ficience pour la Syncytine 2. Cette association exosome/Syncytine 2 devient alors un excellent biomarqueur de la condition prĂ©-Ă©clampsie.\ud
______________________________________________________________________________ \ud
MOTS-CLĂS DE LâAUTEUR : RĂ©troVirus EndogĂšne Humain (HERV), Syncytine 1, Syncytine 2, EnvP(b), EnvV, cytotrophoblaste, placenta, syncytialisation, prĂ©-Ă©clampsie, exosomes, biomarqueur
Expression et fonction des gÚnes env associés aux hervs dans les cellules trophoblastiques humaines
PrĂšs de 8% du gĂ©nome humain est constituĂ© de sĂ©quences d'origine rĂ©trovirale. Ces sĂ©quences nommĂ©es HERVs (Human Endogenous RetroVirus) reprĂ©sentent des vestiges d'intĂ©grations rĂ©trovirales ancestrales qui font maintenant partie de notre gĂ©nome. Certaines de ces sĂ©quences sont toujours aptes Ă produire des protĂ©ines typiques aux rĂ©trovirus, telles que les protĂ©ines de l'enveloppe ou certaines protĂ©ines rĂ©gulatrices. La prĂ©sence des HERVs dans le gĂ©nome humain peut se rĂ©vĂ©ler ĂȘtre associĂ©e Ă divers phĂ©nomĂšnes biologiques, favorisant ainsi l'idĂ©e qu'une corrĂ©lation entre ces rĂ©trovirus endogĂšnes et certaines pathologies, telles que la sclĂ©rose en plaque, la schizophrĂ©nie ou encore la prĂ©-Ă©clampsie pourrait exister. Cependant, il a Ă©tĂ© suggĂ©rĂ© qu'une protĂ©ine d'enveloppe appartenant Ă une sĂ©quence d'HERV, nommĂ©e Syncytine-l, pourrait participer au dĂ©veloppement du placenta. La fonction de cette derniĂšre serait de provoquer des Ă©vĂ©nements de fusion cellulaire entre les cellules cytotrophoblastiques du placenta, permettant la formation de la structure cellulaire nommĂ©e syncytiotrophoblaste. Cependant, d'autres protĂ©ines d'enveloppe d'HERVs dĂ©couvertes rĂ©cemment, telle que la Syncytine-2, pourraient aussi participer Ă ces Ă©vĂ©nements fusogĂ©niques de façon Ă©quivalente, voir plus importante que la Syncytine-l. L'Ă©tude menĂ©e ici a tout d'abord eu pour but d'approfondir et de prĂ©senter des mĂ©canismes possibles de rĂ©gulation du gĂšne Syncytine-l ainsi que d'un autre gĂšne env d'HERVs, soit la Syncytine-2, possiblement impliquĂ©e dans les Ă©vĂ©nements fusogĂ©niques des cellules trophoblastiques. D'abord, des expĂ©riences de 5'/3' RACE ont permis de caractĂ©riser les extrĂ©mitĂ©s du transcrit Syncytine-2. L'expression de ces enveloppes rĂ©trovirales a Ă©tĂ© ensuite Ă©tudiĂ©e en utilisant la technique RT-PCR. En effet, l'ARN total a Ă©tĂ© extrait de diffĂ©rentes lignĂ©es cellulaires de choriocarcinomes trophoblastiques (BeWo, Jar et JEG-3), stimulĂ©es ou non avec les agents activateurs, forskoline (un activateur de l'adĂ©nylate cyclase) et bpV[pic] (un inhibiteur de phosphotyrosine phosphatase) dont l'impact dans les Ă©vĂ©nements de fusion a Ă©tĂ© Ă©tudiĂ© parallĂšlement. D'autres amplifications par RTPCR, utilisant l'ARN de cellules primaires humaines placentaires, ont Ă©tĂ© envisagĂ©es, afin de mettre en Ă©vidence l'expression de ces gĂšnes dans un contexte plus reprĂ©sentatif du placenta. D'autre part, une Ă©tude des diffĂ©rentes activitĂ©s promotrices a Ă©tĂ© rĂ©alisĂ©e Ă l'aide de diffĂ©rents clonages des rĂ©gions LTR-5' de ces deux gĂšnes dans un vecteur rapporteur de la lucifĂ©rase. Dans un second temps, il s'agissait d'Ă©tudier l'implication fonctionnelle de ces deux protĂ©ines d'enveloppe d'HERVs, au cours de la syncytialisation des trophoblastes, par diffĂ©rentes expĂ©riences de fusion en prĂ©sence d'inhibiteurs de l'expression de ces enveloppes rĂ©trovirales telles que des molĂ©cules d'ARN InterfĂ©rents. Enfin, leur localisation cellulaire a Ă©tĂ© mise en Ă©vidence au travers de la microscopie confocale. ______________________________________________________________________________ MOTS-CLĂS DE LâAUTEUR : HERV, RĂ©trovirus endogĂšne, Env, Syncytine-1, Syncytine-2, Placenta, Trophoblaste, Fusion, Syncytium, Expression, Transcription, LTR, Localisation, siRNA
Induction of galectin-1 expression by HTLV-I Tax and its impact on HTLV-I infectivity
© 2008 Gauthier et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
Detection of oxaliplatin- and cisplatin-DNA lesions requires different global genome repair mechanisms that affect their clinical efficacy
The therapeutic efficacy of cisplatin and oxaliplatin depends on the balance between the DNA damage induction and the DNA damage response of tumor cells. Based on clinical evidence, oxaliplatin is administered to cisplatin-unresponsive cancers, but the underlying molecular causes for this tumor specificity are not clear. Hence, stratification of patients based on DNA repair profiling is not sufficiently utilized for treatment selection. Using a combination of genetic, transcriptomics and imaging approaches, we identified factors that promote global genome nucleotide excision repair (GG-NER) of DNA-platinum adducts induced by oxaliplatin, but not by cisplatin. We show that oxaliplatin-DNA lesions are a poor substrate for GG-NER initiating factor XPC and that DDB2 and HMGA2 are required for efficient binding of XPC to oxaliplatin lesions and subsequent GG-NER initiation. Loss of DDB2 and HMGA2 therefore leads to hypersensitivity to oxaliplatin but not to cisplatin. As a result, low DDB2 levels in different colon cancer cells are associated with GG-NER deficiency and oxaliplatin hypersensitivity. Finally, we show that colon cancer patients with low DDB2 levels have a better prognosis after oxaliplatin treatment than patients with high DDB2 expression. We therefore propose that DDB2 is a promising predictive marker of oxaliplatin treatment efficiency in colon cancer.</p
Genetic diversity, linkage disequilibrium and power of a large grapevine (Vitis vinifera L) diversity panel newly designed for association studies
UMR-AGAP Equipe DAVV (DiversitĂ©, adaptation et amĂ©lioration de la vigne) ; Ă©quipe ID (IntĂ©gration de DonnĂ©es)International audienceAbstractBackgroundAs for many crops, new high-quality grapevine varieties requiring less pesticide and adapted to climate change are needed. In perennial species, breeding is a long process which can be speeded up by gaining knowledge about quantitative trait loci linked to agronomic traits variation. However, due to the long juvenile period of these species, establishing numerous highly recombinant populations for high resolution mapping is both costly and time-consuming. Genome wide association studies in germplasm panels is an alternative method of choice, since it allows identifying the main quantitative trait loci with high resolution by exploiting past recombination events between cultivars. Such studies require adequate panel design to represent most of the available genetic and phenotypic diversity. Assessing linkage disequilibrium extent and panel power is also needed to determine the marker density required for association studies.ResultsStarting from the largest grapevine collection worldwide maintained in Vassal (France), we designed a diversity panel of 279 cultivars with limited relatedness, reflecting the low structuration in three genetic pools resulting from different uses (table vs wine) and geographical origin (East vs West), and including the major founders of modern cultivars. With 20 simple sequence repeat markers and five quantitative traits, we showed that our panel adequately captured most of the genetic and phenotypic diversity existing within the entire Vassal collection. To assess linkage disequilibrium extent and panel power, we genotyped single nucleotide polymorphisms: 372 over four genomic regions and 129 distributed over the whole genome. Linkage disequilibrium, measured by correlation corrected for kinship, reached 0.2 for a physical distance between 9 and 458 Kb depending on genetic pool and genomic region, with varying size of linkage disequilibrium blocks. This panel achieved reasonable power to detect associations between traits with high broad-sense heritability (>â0.7) and causal loci with intermediate allelic frequency and strong effect (explainingâ>â10 % of total variance).ConclusionsOur association panel constitutes a new, highly valuable resource for genetic association studies in grapevine, and deserves dissemination to diverse field and greenhouse trials to gain more insight into the genetic control of many agronomic traits and their interaction with the environment
Identification of genetic variants associated with Huntington's disease progression: a genome-wide association study
Background Huntington's disease is caused by a CAG repeat expansion in the huntingtin gene, HTT. Age at onset has been used as a quantitative phenotype in genetic analysis looking for Huntington's disease modifiers, but is hard to define and not always available. Therefore, we aimed to generate a novel measure of disease progression and to identify genetic markers associated with this progression measure. Methods We generated a progression score on the basis of principal component analysis of prospectively acquired longitudinal changes in motor, cognitive, and imaging measures in the 218 indivduals in the TRACK-HD cohort of Huntington's disease gene mutation carriers (data collected 2008â11). We generated a parallel progression score using data from 1773 previously genotyped participants from the European Huntington's Disease Network REGISTRY study of Huntington's disease mutation carriers (data collected 2003â13). We did a genome-wide association analyses in terms of progression for 216 TRACK-HD participants and 1773 REGISTRY participants, then a meta-analysis of these results was undertaken. Findings Longitudinal motor, cognitive, and imaging scores were correlated with each other in TRACK-HD participants, justifying use of a single, cross-domain measure of disease progression in both studies. The TRACK-HD and REGISTRY progression measures were correlated with each other (r=0·674), and with age at onset (TRACK-HD, r=0·315; REGISTRY, r=0·234). The meta-analysis of progression in TRACK-HD and REGISTRY gave a genome-wide significant signal (p=1·12 Ă 10â10) on chromosome 5 spanning three genes: MSH3, DHFR, and MTRNR2L2. The genes in this locus were associated with progression in TRACK-HD (MSH3 p=2·94 Ă 10â8 DHFR p=8·37 Ă 10â7 MTRNR2L2 p=2·15 Ă 10â9) and to a lesser extent in REGISTRY (MSH3 p=9·36 Ă 10â4 DHFR p=8·45 Ă 10â4 MTRNR2L2 p=1·20 Ă 10â3). The lead single nucleotide polymorphism (SNP) in TRACK-HD (rs557874766) was genome-wide significant in the meta-analysis (p=1·58 Ă 10â8), and encodes an aminoacid change (Pro67Ala) in MSH3. In TRACK-HD, each copy of the minor allele at this SNP was associated with a 0·4 units per year (95% CI 0·16â0·66) reduction in the rate of change of the Unified Huntington's Disease Rating Scale (UHDRS) Total Motor Score, and a reduction of 0·12 units per year (95% CI 0·06â0·18) in the rate of change of UHDRS Total Functional Capacity score. These associations remained significant after adjusting for age of onset. Interpretation The multidomain progression measure in TRACK-HD was associated with a functional variant that was genome-wide significant in our meta-analysis. The association in only 216 participants implies that the progression measure is a sensitive reflection of disease burden, that the effect size at this locus is large, or both. Knockout of Msh3 reduces somatic expansion in Huntington's disease mouse models, suggesting this mechanism as an area for future therapeutic investigation
A CRE/AP-1-like motif is essential for induced syncytin-2 expression and fusion in human trophoblast-like model.
Syncytin-2 is encoded by the envelope gene of Endogenous Retrovirus-FRD (ERVFRD-1) and plays a critical role in fusion of placental trophoblasts leading to the formation of the multinucleated syncytiotrophoblast. Its expression is consequently regulated in a strict manner. In the present study, we have identified a forskolin-responsive region located between positions -300 to -150 in the Syncytin-2 promoter region. This 150 bp region in the context of a minimal promoter mediated an 80-fold induction of promoter activity following forskolin stimulation. EMSA analyses with competition experiments with nuclear extracts from forskolin-stimulated BeWo cells demonstrated that the -211 to -177 region specifically bound two forskolin-induced complexes, one of them containing a CRE/AP-1-like motif. Site-directed mutagenesis of the CRE/AP-1 binding site in the context of the Syncytin-2 promoter or a heterologous promoter showed that this motif was mostly essential for forskolin-induced promoter activity. Transfection experiments with dominant negative mutants and constitutively activated CREB expression vectors in addition to Chromatin Immunoprecipitation suggested that a CREB family member, CREB2 was binding and acting through the CRE/AP-1 motif. We further demonstrated the binding of JunD to this same motif. Similar to forskolin and soluble cAMP, CREB2 and JunD overexpression induced Syncytin-2 promoter activity in a CRE/AP-1-dependent manner and Syncytin-2 expression. In addition, BeWo cell fusion was induced by both CREB2 and JunD overexpression, while being repressed following silencing of either gene. These results thereby demonstrate that induced expression of Syncytin-2 is highly dependent on the interaction of bZIP-containing transcription factors to a CRE/AP-1 motif and that this element is important for the regulation of Syncytin-2 expression, which results in the formation of the peripheral syncytiotrophoblast layer
Pro-inflammatory cytokines expression in neutrophils at 24 hours.
<p>Equine neutrophils (n = 6) were cultured (24 hours) in presence or absence of IL-17, LPS and dexamethasone (DEX). (A). IL-1ÎČ, (B). IL-6, (C). IL-8, and (D). TNF-α mRNA expression were evaluated by qPCR. Each symbol represents the mean of an experiment run in duplicate for every horse.</p
Upregulation of Human T-Cell Leukemia Virus Type 1 Antisense Transcription by the Viral Tax Proteinâż
Several studies have recently demonstrated the existence of human T-cell leukemia virus type 1 (HTLV-1) antisense transcripts, which allow the synthesis of the newly described HBZ protein. Although previous reports have been aimed at understanding the potential role of the HBZ protein in HTLV-1 pathogenesis, little is known as to how this viral gene is regulated. Here, using our K30-3âČasLuc reporter construct, we show that the viral Tax protein upregulates antisense transcription through its action on the TRE sequences located in the 3âČ long terminal repeat. Generation of stable clones in 293T cells demonstrated that Tax-induced HBZ expression is importantly influenced by the integration site in the host genome. The cellular DNA context could thus affect the level of HBZ mRNA expression in infected cells
- âŠ