Découverte de nouvelles interactions entre le virus de l'Hépatite C et l'hôte par une approche combinée de Spectrométrie de Masse et de Génomique Fonctionnelle

La réplication et l’assemblage du virus de l’hépatite C (VHC) sont régulés finement dans le temps et l’espace par les interactions protéiques entre le virus avec l’hôte. La compréhension de la biologie du virus ainsi que sa pathogénicité passe par les connaissances relatives aux interactions virus/hôte. Afin d’identifier ces interactions, nous avons exploité une approche d’immunoprécipitation (IP) couplée à une détection par spectrométrie de masse (MS), pour ensuite évaluer le rôle des protéines identifiées dans le cycle viral par une technique de silençage génique. Les protéines virales Core, NS2, NS3/4A, NS4B, NS5A et NS5B ont été exprimées individuellement dans les cellules humaines 293T et immunoprécipitées afin d’isoler des complexes protéiques qui ont été soumis à l’analyse MS. Ainsi, 98 protéines de l’hôte ont été identifiées avec un enrichissement significatif et illustrant une spécificité d’interaction. L’enrichissement de protéines connues dans la littérature a démontré la force de l’approche, ainsi que la validation de 6 nouvelles interactions virus/hôte. Enfin, le rôle de ces interactants sur la réplication virale a été évalué dans un criblage génomique par ARN interférant (ARNi). Deux systèmes rapporteurs de la réplication virale ont été utilisés : le système de réplicon sous-génomique (Huh7-Con1-Fluc) et le système infectieux (J6/JFH-1/p7Rluc2a), ainsi qu’un essai de toxicité cellulaire (Alamar Blue). Parmi les protéines de l’hôte interagissant avec le VHC, 28 protéines ont démontré un effet significatif sans effet de toxicité cellulaire, suggérant fortement un rôle dans la réplication du VHC. Globalement, l’étude a mené à l’identification de nouvelles interactions virus/hôte et l’identification de nouvelles cibles thérapeutiques potentielles.Hepatitis C virus (HCV) replication and assembly are tightly regulated in time and space within the cell, most likely due to protein interactions between virus and host. In order to better understand HCV biology and its pathogenesis, there is a need to unravel virus/host interaction network. We extended our knowledge of virus/host interactions by the identification of cellular proteins associated to HCV proteins using an immunoprecipitation (IP) technique coupled to mass spectrometry (MS), and further evaluate the role of retrieved interactors using gene knockdown. FLAG-tagged viral proteins Core, NS2, NS3/4A, NS4B, NS5A and NS5B have been expressed individually in 293T human cells, and immunoprecipitated protein complexes have been submitted to MS analysis for identification of host proteins. In this study, 98 proteins were significantly enriched and showed specific interaction to a viral protein. Retrieval of previously characterized interacting proteins proved the strength of the method. Six newly identified interactors by MS were individually confirmed using IP of viral proteins. We evaluated the role of identified interactors in HCV replication by performing a functional lentivirus-based RNA interference (RNAi) screen. Two reporter systems were used: the sub- genomic replicon (Huh7-Con1-Fluc) and a full length infectious clone (J6/JFH-1/p7Rluc2a), as well as the cellular toxicity assay Alamar blue. Of the identified host interactors, 28 proteins showed a significant effect on HCV replication upon gene knockdown and without cellular toxicity. Overall, the study led to the identification of novel virus/host interactions essential in HCV life cycle and provides novel potential drug targets

Les représentations sociales et les préoccupations en matière d’environnement chez les jeunes du Sénégal : une étude comparative en milieu urbain chez les jeunes scolarisés de Dakar

Le Sénégal est confronté à plusieurs enjeux environnementaux accentués par l’exode rural, la croissance démographique et l’urbanisation galopante. Dans la capitale de Dakar, les populations sont exposées à des risques industriels, sanitaires et environnementaux importants. Face aux conséquences néfastes des phénomènes de la dégradation de l’environnement en milieu urbain, il convient de chercher à mieux comprendre ce que l’environnement représente pour les populations notamment chez la jeune génération qui aura à vivre avec les conséquences liées à la détérioration de l'environnement léguée par les générations précédentes. S’appuyant sur la théorie des représentations sociales, cette recherche a comme objectifs 1) d’explorer les représentations sociales de l’environnement chez les jeunes sénégalais âgés de 9 à 16 ans en milieu scolaire situé en milieu urbain, et ce, dans différentes écoles de la ville de Dakar ; 2) d’étudier les connaissances, les sensibilités et les comportements des jeunes en matière écologique et environnementale; 3) finalement de déterminer les principaux agents responsables de la socialisation des jeunes dakarois en matière d’environnement. Le tout analysé en fonction de trois variables soit l’âge, le genre et le type d’école. La méthodologie de notre recherche est essentiellement qualitative de type exploratoire et elle s’appui principalement sur des questionnaires et des dessins. Les résultats montrent qu’en ce qui concerne les représentations sociales de l’environnement des jeunes dakarois, à travers l’analyse du discours, que l’environnement est représenté par les catégories typologiques dites « négative » « utilitariste » et « milieu de vie ». Ces représentations sociales varient à divers degrés en fonction du groupe d’âge, du genre et du type d’école. Les jeunes sont également nombreux à utiliser un vocabulaire associé aux notions liées à l’environnement naturel. De son côté, l’analyse picturale, qui concorde avec l’analyse lexicale, montre que les catégories typologiques de l’environnement sont liées au « milieu de vie », à l’« environnement ressource » et à l’« environnement nature » et ce, peu importe l’âge, le type d’école et le genre.Senegal faces many environmental problems that are exacerbated by rural-urban migration, population growth and increasing urbanization. In the capital, Dakar, people are exposed to important industrial, health and environmental hazards. Given the negative impacts of environmental degradation on urban settlements, it is crucial to acquire a deeper understanding of social representations of the environment among the urban population, especially among the younger generations, who will have to bear the consequences of the environmental deterioration caused by previous generations. Based on the theory of social representations, this research aimed to: 1) explore the social representations of the environment among young Senegalese, aged 9 to 16, in different schools in the city of Dakar; 2) study their knowledge, attitudes and behavior in relation to environmental and ecological issues, and; 3) determine the main agents creating environmental awareness among young people in Dakar. The analysis was based on age, gender and school-type variables. The methodology employed in this research was essentially qualitative-exploratory, and based mainly on questionnaires and drawings. Discourse analysis yields three typological categories of social representations of the environment among young people in Dakar: "negative" "utilitarian" and "living environment". These social representations differ in varying degrees depending on the age group, gender and school-type. A large number of youth are also using a vocabulary associated with concepts related to the natural environment. The pictorial analysis, which is consistent with the lexical analysis of the questionnaires, shows that the typological categories of environment are related to the "living environment" to "natural resources" and to "nature". These categories emerged regardless of age, school-type or gender group

Les comportements d'achat et le cycle de vie des ménages canadiens

L'objectif premier de cette recherche est de vérifier si le modèle du cycle de vie de la famille de Wells et Gubar de 1966 représente bien l'ensemble de la population canadienne. Dans un cas de non-représentativité, un second objectif se définit : vérifier s'il est possible de segmenter les ménages canadiens selon leur cycle de vie et leurs comportements d'achat en représentant mieux les réalités sociodémographiques actuelles. Utilisant l'Enquête sur les dépenses des ménages de Statistique Canada (2009), notre recherche étudie 13 catégories de dépenses : les vêtements, l'alimentation, les loisirs, le transport, les soins de santé, l'ameublement et l'équipement ménager, le logement, l'entretien ménager, les soins personnels, le matériel de lecture, l'éducation, le tabac et les boissons alcoolisées et finalement, l'assurance individuelle et les cotisations de retraite. Chaque dépense est analysée selon deux mesures : les montants d'agents bruts dépensés annuellement et le pourcentage de la catégorie en proportion des dépenses totales. Les trois hypothèses de recherche sont validées, permettant de confirmer, dans un premier temps (H1), la non-représentativité du modèle de Wells et Gubar de 1966. En second lieu (H2), notre étude valide l'importance de l'intégration des ménages célibataires au modèle du cycle de vie par leurs comportements d'achat significativement différents des ménages traditionnels. Troisièmement (H3), il est possible de créer des segmentations marketing, basées sur les critères du cycle de vie, tenant mieux compte des réalités canadiennes. En plus de proposer 26 segmentations marketing parcimonieuses et exhaustives (deux pour chacune des 13 catégories de dépenses), ce mémoire met à jour le concept sur le plan sociologique par la conception d'un modèle du cycle de vie constitué de 21 groupes représentatifs de la population canadienne. Les segmentations marketing proposées permettent aux gestionnaires de chaque industrie de savoir concrètement sur quel groupe miser en termes d'importance de marché et en termes d'importance de la catégorie pour les groupes par rapport à leurs dépenses totales.\ud ______________________________________________________________________________ \ud MOTS-CLÉS DE L’AUTEUR : Cycle de vie, comportements d'achat, ménage, dépenses, Canada

Regulation of COX-2 protein expression by Akt in endometrial cancer cells is mediated through NF-κB/IκB pathway

BACKGROUND: Cyclooxygenase-2 (COX-2) has been shown to be highly expressed in a broad series of primary endometrial tumors and its expression may be closely associated with parameters of tumor aggressiveness. In human endometrial cancer, tumor suppressor phosphatase tensin homologue (PTEN) is frequently mutated. In the presence of a mutated PTEN protein, Akt phosphorylation levels increase leading to the activation of this survival pathway. The nuclear transcription factor κB (NF-κB) is a well establish regulator of genes encoding cytokines, cytokine receptors, and cell adhesion molecules that drive immune and inflammatory responses. More recently, NF-κB activation has been connected with multiple aspects of oncogenesis, including the control of apoptosis, cell cycle, differentiation, and cell migration. It is known that Akt may act through NF-κB pathway and that COX-2 gene has been shown to be regulated at the promoter level by NF-κB. Recently, we showed that Akt regulates COX-2 gene and protein expressions in phospho-Akt expressing endometrial cancer cells. The present study was undertaken to determine the involvement of NF-κB pathway and IκB (an inhibitor of NF-κB) in the regulation of COX-2 expression and to determine more precisely the downstream targets of Akt involved in this process. RESULTS: Three different human endometrial cancer cell lines known to have wild type PTEN (HEC 1-A) or a mutated inactive PTEN protein (RL 95-2 and Ishikawa) were used for these studies. Expression IκB and Phospho-IκB were evaluated by Western analysis. The presence of IκB phosphorylation was found in all cell lines studied. There was no difference between cell lines in term of NF-κB abundance. Inhibition of PI 3-K with Wortmannin and LY294002 blocked IκB phosphorylation, reduced NF-κB nuclear activity, reduced COX-2 expression and induced apoptosis. Transfection studies with a dominant negative Akt vector blocked IκB phosphorylation and reduced COX-2 expression. On the opposite, constitutively active Akt transfections resulted in the induction of IκB phosphorylation and up-regulation of COX-2. CONCLUSION: These results demonstrate that Akt signals through NF-κB/IκB pathway to induce COX-2 expression in mutated PTEN endometrial cancer cells

Solidarity Economy in Montreal: Women's Activism Creating Alternatives Through the Ethics of Care

The feminization of poverty has been, and still is, a problem in North America. Canadian public policies have a negative affect on women, especially those who are mothers, single or elderly. Large urban centres such as Montréal, Québec have a large proportion of women living on low incomes or on social assistance. Through participant observation at Food Central, a community organization, I interacted with these women and the women activists who work with them to assist in easing the difficulties women experience in providing for their families and themselves when household income is insufficient to cover monthly bills. My fieldwork was conducted from August 2008-March 2009, some of the most expensive months of the year for many women. Québec’s history of social upheavals since the 1960s and its economic instability has created a situation that closely parallels Latin American countries. Both Québec and Latin American countries have increasingly large and popular activist organizations seeking social justice. Many of the grassroots Latin American activist organizations are creating alternatives to the globalized capitalist economy such as “economía solidaria” which is based on an ethics of care, reciprocity, and non-monetary forms of exchanges. This thesis presents the narratives and life stories of the women activists, volunteers and women who came to Food Central as clients to learn what alternatives to the formal economy if any, the women use as strategies of survival in a large city

Solidarity economy in Montréal : women's activism creating alternatives through the ethics of care

The feminization of poverty has been, and still is, a problem in North America. Canadian public policies have a negative affect on women, especially those who are mothers, single or elderly. Large urban centres such as Montréal, Québec have a large proportion of women living on low incomes or on social assistance. Through participant observation at Food Central, a community organization, I interacted with these women and the women activists who work with them to assist in easing the difficulties women experience in providing for their families and themselves when household income is insufficient to cover monthly bills. My fieldwork was conducted from August 2008-March 2009, some of the most expensive months of the year for many women. Québec's history of social upheavals since the 1960s and its economic instability has created a situation that closely parallels Latin American countries. Both Québec and Latin American countries have increasingly large and popular activist organizations seeking social justice. Many of the grassroots Latin American activist organizations are creating alternatives to the globalized capitalist economy such as " economía solidaria " which is based on an ethics of care, reciprocity, and non-monetary forms of exchanges. This thesis presents the narratives and life stories of the women activists, volunteers and women who came to Food Central as clients to learn what alternatives to the formal economy if any, the women use as strategies of survival in a large city

Isoflavone rich soy protein isolate exerts significant bone sparing effects in the lumbar spine but not symptom relief in perimenopausal women

In this double-blind 24-week study, we examined the effects of isoflavone-rich (80.4 mg/d) soy protein isolate in attenuating bone loss and symptom relief during the menopausal transition. Sixty-nine subjects were randomized to treatment: isoflavone-rich soy (SPI+; n=24), isoflavone-deficient soy (SPI-; n=24), or whey (Control; n=21) protein. At baseline and post-treatment, we measured lumbar spine bone mineral density (BMD) via dual-energy x-ray absorptiometry. At baseline, mid-, and post-treatment, we measured urinary N-telopeptides (N-Tx) and serum bone-specific alkaline phosphatase (BAP), reproductive hormones, and menopausal symptoms. Percentage change in lumbar spine BMD did not decline in the SPI+ group (-0.2%, p=0.73); however, significant loss occurred in the Control (-1.3%, p=0.0041) and loss approached significance in SPI- (-0.7%, p=0.097) groups. Multiple regression analysis indicated that isoflavone treatment had a significant positive effect on % change in BMD (p=0.023). Baseline BMD (p[Less than or equal to]0.0001) significantly affected (negatively) % change in BMD, whereas baseline body weight (p=0.0036) and bone-free lean weight (p=0.016), contributed (positively). Serum BAP at post-treatment negatively affected % change in BMD (p=0.0016). Contrast coding using ANCOVA with BMD as the outcome, indicated that it was the isoflavones, not the soy protein exerting the effect. Serum BAP did not decline in the SPI+ (p=0.90) and SPI- (p= 0.76) groups, whereas the Control had some decline (p=0.092; NS). Urinary N-Tx did not decline with isoflavone treatment (p=0.91) at week 12, in contrast to the other groups, and increased in each group from mid-to post-treatment. Repeated measures ANOVA indicated no treatment effect on frequency of hot flushes and night sweats. Chi-Square analyses indicated no treatment effect on severity of hot flushes or night sweats with the exception of night sweats (p = 0.036) at mid-treatment using the menopausal diary. Chi-Square analyses also indicated no treatment effect on frequency or severity of insomnia, limb numbness, headaches, and fatigue. Overall, these results indicate that soy isoflavones attenuate bone loss from the lumbar spine but do not cause symptom relief in estrogen-deficient perimenopausal women

Die metallogenetische Entwicklung des Krivoy Rog-Eisenerzbezirkes im Ukrainischen Schild

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