L’utilisation des réseaux sociaux (Snapchat, WhatsApp et Instagram) et le cyberbullying

100% des jeunes possèdent un téléphone portable, 99% ont un ordinateur et 97% ont accès à Internet (Waller et al., 2016). Ces nouveaux moyens technologiques font partie de notre quotidien. Depuis l’apparition de ces réseaux, un nouveau mouvement est né : le cyberbullying. Ce harcèlement par Internet consiste à l’utilisation de technologies modernes de communication afin de nuire aux autres de manière délibérée et agressive. Quand les jeunes arrivent en classe, ils apportent avec eux l’entier de leur vécu quotidien, familial ou encore émotionnel. Les problèmes liés à l’utilisation massive de ces réseaux font partie de notre quotidien d’enseignant. Malheureusement, les études faites jusqu’au jour d’aujourd’hui portent en majeure partie sur les élèves entre 13 ans et plus. Mais qu’en est-il des jeunes âgés entre 9 et 12 ans ? Notre travail de recherche porte donc sur l’utilisation des réseaux sociaux (Snapchat, Instagram et WhatsApp) et le cyberbullying. Deux outils différents ont été utilisés lors de cette recherche : des questionnaires afin d’avoir des résultats quantitatifs et deux entretiens afin d’avoir un point de vue qualitatif. Nos résultats montrent que WhatsApp est le réseau social le plus utilisé, suivi d’Instagram en deuxième position et finalement de Snapchat. Les élèves considèrent le nombre de dangers et de conflits sur les réseaux comme très faibles. Ils avouent tout de même donner plus d’informations personnelles sur WhatsApp que sur les autres réseaux choisis dans l’étude. Concernant leur vision du contrôle des parents, ils l’estiment très faible. Cependant, il s’agit uniquement de leur avis, il serait intéressant de savoir la réalité des faits en interrogeant les parents. Les deux sujets interrogés savent définir le cyberbullying et connaissent les différents acteurs agissant au sein de cette forme de harcèlement. Ils sont également conscients des différents risques, conséquences ou sentiments que peut ressentir une cyber-victime mais n’abordent pas du tout ceux concernant le témoin ou le cyber-harceleur. En conclusion, notre recherche montre que les réseaux sociaux font partie intégrante du quotidien d’un grand nombre d’élèves. Il est donc essentiel que les enseignants s’interrogent sur les moyens de gérer les problèmes que ceux-ci peuvent amener en classe mais également les moyens de les éviter

Clusterin expression can be modulated by changes in TCF1-mediated Wnt signaling-1

<p><b>Copyright information:</b></p><p>Taken from "Clusterin expression can be modulated by changes in TCF1-mediated Wnt signaling"</p><p>http://www.jmolecularsignaling.com/content/2/1/6</p><p>Journal of Molecular Signaling 2007;2():6-6.</p><p>Published online 16 Jul 2007</p><p>PMCID:PMC1976611.</p><p></p>the effectors of the Wnt pathway, were over-expressed in stably transfected LS174T derived cell lines. Proliferation was halted in LS174T derived cell lines after induction of both dnTCFs. This was visualised by methyl violet staining of cell cultures after 5 days of induction. Similar results were obtained by manually counting cells in a haemocytometer after cells had been cultured in the presence (+) or absence (-) of induction for 4 days. Data are presented as the mean ± standard deviation from 3 separate experiments. Induction of exogenous gene products, dnTCFs, was detected by western blot with cell lysates from LS174T derived cell lines 0, 12, and 24 hr after induction. Control cells are LS174T cells without any dnTCF expression vector. Both dnTCF1 and dnTCF4 abrogate β-catenin/TCF driven transcription of the Wnt-target gene, c-MYC, as analyzed by western blot with cell lysates from LS174T derived cell lines 0 and 12 hr after induction

Clusterin expression can be modulated by changes in TCF1-mediated Wnt signaling-4

<p><b>Copyright information:</b></p><p>Taken from "Clusterin expression can be modulated by changes in TCF1-mediated Wnt signaling"</p><p>http://www.jmolecularsignaling.com/content/2/1/6</p><p>Journal of Molecular Signaling 2007;2():6-6.</p><p>Published online 16 Jul 2007</p><p>PMCID:PMC1976611.</p><p></p>DNA ends (RACE) to determine the sequence of the extreme 5'-end of CLU34 mRNA. None of the three cloned 5'-end RACE fragments or the RT PCR analysis supported the most 5' extreme end of the CLU34 transcript containing the putative TATA-box as suggested by the RefSeq database. The 5'-end RACE results were consistent with results from RT-PCR reactions which only yielded an amplification product if the sense primer was placed downstream of the putative TATA-box

Clusterin expression can be modulated by changes in TCF1-mediated Wnt signaling-8

<p><b>Copyright information:</b></p><p>Taken from "Clusterin expression can be modulated by changes in TCF1-mediated Wnt signaling"</p><p>http://www.jmolecularsignaling.com/content/2/1/6</p><p>Journal of Molecular Signaling 2007;2():6-6.</p><p>Published online 16 Jul 2007</p><p>PMCID:PMC1976611.</p><p></p>f GFP tagged E-cadherin and GFP as control. Immunofluorescence was used to show the effects of transient over-expression of GFP tagged E-cadherin, which binds β-catenin, in LS174T and HCT116 colon carcinoma cell lines. In the left panel it is shown that the GFP-cyt-E-cadherin fusion protein efficiently sequesters β-catenin from the nucleus whereupon Wnt signaling is abrogated. In transfected cells (white arrow heads) β-catenin has a perinuclear localization contrasting untransfected cells (white arrows) where it is uniformly distributed. Shown in the right panel is the up-regulation of cytoplasmic CLU protein which follows the abrogation of Wnt signaling induced by the GFP-cyt-E-cadherin fusion protein. CLU is up-regulated in GFP-cyt-E-cadherin transfected cells (yellow arrow heads) but not in untransfected cells nor in cells transfected with GFP alone. Western blot with cell lysates from LS174T cells 24 hr after transient transfection with GFP-cyt-E-cadherin and GFP as a control. β-actin was used as a loading control. CLU protein levels are up-regulated and c-MYC protein levels are down-regulated as a consequence of over-expressing GFP-cyt-E-cadherin but not GFP alone. WB: western blot, ab: Antibody

Clusterin expression can be modulated by changes in TCF1-mediated Wnt signaling-6

<p><b>Copyright information:</b></p><p>Taken from "Clusterin expression can be modulated by changes in TCF1-mediated Wnt signaling"</p><p>http://www.jmolecularsignaling.com/content/2/1/6</p><p>Journal of Molecular Signaling 2007;2():6-6.</p><p>Published online 16 Jul 2007</p><p>PMCID:PMC1976611.</p><p></p>after induction of dnTCFs in LS174T derived cell lines. Expression levels were normalized to the Ubiquitin C (UBC) transcript. The CLU34 mRNA variant is specifically up-regulated in response to dnTCF1 over-expression in LS174T cells. Data are presented as the mean ± standard deviation from 2 separate experiments with each experiment consisting of the mean value of 3 independent determinations. c-MYC mRNA levels decrease, whereas p21mRNA levels increase after induction of both dnTCFs

Clusterin expression can be modulated by changes in TCF1-mediated Wnt signaling-3

<p><b>Copyright information:</b></p><p>Taken from "Clusterin expression can be modulated by changes in TCF1-mediated Wnt signaling"</p><p>http://www.jmolecularsignaling.com/content/2/1/6</p><p>Journal of Molecular Signaling 2007;2():6-6.</p><p>Published online 16 Jul 2007</p><p>PMCID:PMC1976611.</p><p></p>4T cells 48 hr after induction (p < 0.005, student's t-test). This was determined using two cell death assays based on either trypan blue dye or DNA-intercalating dyes, propidium iodide (PI) and hoechst 342 (HST). LS174T control and dnTCF1 cell lines were cultured in the presence of induction. After 24 hr and 48 hr, floating and attached cells were stained with the respective dyes. Data from both assays are presented as the mean ± standard deviation from 3 separate experiments. PI/HST assay: Cells were stained with PI (stains apoptotic/necrotic cells) and HST (stains viable cells). Percentage of PI stained cells relative to total cell number reflect the extent of cell death. Trypan blue dye exclusion assay: Cells were stained with the trypan blue dye. Percentage of trypan blue stained cells (stains dead cells) relative to total cell number reflect extent of cell death. MTT viability assay: The cells' capability to metabollically convert the MTT substrate was quantified, 48 hr after either induction (+dox) or no induction (-dox), by solubilizing MTT formazan crystals and performing spectrophotometry at 540 nm. Cell viability, which is proportional to the absorbance at 540 nm, decreases in dnTCF1 over-expressing LS174T cells relative to control cells

Clusterin expression can be modulated by changes in TCF1-mediated Wnt signaling-0

<p><b>Copyright information:</b></p><p>Taken from "Clusterin expression can be modulated by changes in TCF1-mediated Wnt signaling"</p><p>http://www.jmolecularsignaling.com/content/2/1/6</p><p>Journal of Molecular Signaling 2007;2():6-6.</p><p>Published online 16 Jul 2007</p><p>PMCID:PMC1976611.</p><p></p>f GFP tagged E-cadherin and GFP as control. Immunofluorescence was used to show the effects of transient over-expression of GFP tagged E-cadherin, which binds β-catenin, in LS174T and HCT116 colon carcinoma cell lines. In the left panel it is shown that the GFP-cyt-E-cadherin fusion protein efficiently sequesters β-catenin from the nucleus whereupon Wnt signaling is abrogated. In transfected cells (white arrow heads) β-catenin has a perinuclear localization contrasting untransfected cells (white arrows) where it is uniformly distributed. Shown in the right panel is the up-regulation of cytoplasmic CLU protein which follows the abrogation of Wnt signaling induced by the GFP-cyt-E-cadherin fusion protein. CLU is up-regulated in GFP-cyt-E-cadherin transfected cells (yellow arrow heads) but not in untransfected cells nor in cells transfected with GFP alone. Western blot with cell lysates from LS174T cells 24 hr after transient transfection with GFP-cyt-E-cadherin and GFP as a control. β-actin was used as a loading control. CLU protein levels are up-regulated and c-MYC protein levels are down-regulated as a consequence of over-expressing GFP-cyt-E-cadherin but not GFP alone. WB: western blot, ab: Antibody

Clusterin expression can be modulated by changes in TCF1-mediated Wnt signaling-5

<p><b>Copyright information:</b></p><p>Taken from "Clusterin expression can be modulated by changes in TCF1-mediated Wnt signaling"</p><p>http://www.jmolecularsignaling.com/content/2/1/6</p><p>Journal of Molecular Signaling 2007;2():6-6.</p><p>Published online 16 Jul 2007</p><p>PMCID:PMC1976611.</p><p></p>ial TCF-binding sites (red arrows) predicted by the MatInspector software. Exonic structure of CLU mRNA variants