Élaboration d’un outil de formation pour l’accueil adéquat du dévoilement d’un ou d’une enfant victime d’agression sexuelle par le personnel enseignant du primaire

Avec l'implantation du programme d'éducation à la sexualité obligatoire, certaines personnes enseignantes ressentent des réticences, plus particulièrement en ce qui concerne la thématique de l’agression sexuelle. Ces réticences semblent liées au fait que ces personnes devront possiblement accueillir le dévoilement d’élèves victimes d’agression sexuelle, qu’elles évaluent leur sentiment d’efficacité personnelle (SEP) à cet égard peu élevé et qu’elles ne connaissent pas nécessairement les procédures à suivre dans une telle situation. Ainsi, ce projet de recherche a pour but de créer un outil de formation qui présente et explique les procédures à suivre pour accueillir le dévoilement d’un ou d’une enfant victime d’agression sexuelle tout en s’appuyant sur la théorie du SEP pour le développer. Cet outil, qui prend la forme d’une vidéo, comprend une partie qui décrit ces procédures et une autre qui les exemplifie à l’aide d’une personne enseignante qui explique sa propre expérience d’accueil de dévoilement

Exploring the roles of RhoA and Collapsin Response Mediator Protein 4 (CRMP4) in the response to cellular damage

The cytoskeleton is an essential structural component of eukaryotic cells that provides mechanical support, and mediates rapid responses to extrinsic and intrinsic stimuli. In neurons, this intricate meshwork underlies many cellular functions, including neurite outgrowth and guidance as well as synaptic plasticity. However, the cytoskeleton can become disorganized following injury and its reassembly is key to recovery. Several proteins regulate cytoskeletal dynamics in the developing and injured nervous system. In this thesis, I focused on two of these regulatory proteins, collapsin response mediator protein 4 (CRMP4) and RhoA, as they are key players in the failure of neuronal regeneration observed following injury. Primarily expressed in the nervous system, CRMP4 is a phospho-protein that possesses growth-promoting roles in developing neurons and growth-inhibitory functions in the injured central nervous system (CNS). However, its functions in the neuronal response to injury in the peripheral nervous system (PNS) remained unclear and thus, I investigated those in chapter 2. I found that CRMP4 facilitates the regrowth of the axons of damaged sensory neurons, while its calpain-dependent cleavage contributes to Wallerian degeneration. Through its combined effects, CRMP4 facilitates PNS regeneration. On the other hand, the ubiquitously expressed small GTPase RhoA is involved in many cellular functions during development, adulthood and in response to various insults. Due to its broad expression and functions, it is tightly regulated by several mechanisms. In chapter 3, I characterized a novel proteolytic event that regulates RhoA in response to cell stress. I found that the fragments generated upon RhoA cleavage affect the actin cytoskeleton by regulating the assembly of stress fibres and nuclear rods. Overall, the findings of this thesis further our understanding of the functions of CRMP4 and of the regulation of RhoA in the cellular response to damage. These findings could be extrapolated to other injury models and thus, they become key to the identification of novel targets that could be used to develop more specific therapies to improve the neuronal response to various insults.Le cytosquelette est un composant structurel essentiel des cellules eucaryotes qui fournit un support mécanique et permet des réponses rapides aux stimuli extrinsèques et intrinsèques. Dans les neurones, ce maillage complexe sous-tend de nombreuses fonctions cellulaires, notamment la croissance et la navigation des neurites ainsi que la plasticité synaptique. Cependant, le cytosquelette peut devenir désorganisé suite à un dommage et son réassemblage est clé au rétablissement fonctionel. Plusieurs protéines régulent la dynamique du cytosquelette dans le système nerveux en développement et suite à une blessure. Dans cette thèse, je me concentre sur deux de ces protéines régulatrices, collapsin response mediator protein 4 (CRMP4) et RhoA, car celles-ci jouent un rôle important à l’échec de la regeneration neuronale observé suite à un dommage. Exprimée principalement dans le système nerveux, CRMP4 est une phospho-protéine qui joue un rôle favorable au development des neurones, alors qu'elle est inhibitoire dans le système nerveux central (SNC) endommagé. Cependant, ses fonctions dans la réponse neuronale suite à une lésion du système nerveux périphérique (SNP) demeurent inconnues et donc, nous investigons celles-ci dans le chapitre 2. J’ai constaté que CRMP4 facilite la repousse des axones des neurones sensoriels endommagés, tandis que son clivage par calpaïne contribue à la dégénérescence wallérienne. Grâce à ses effets combinés, CRMP4 facilite la régénération du SNP. D'autre part, omniprésente dans les cellules, la petite GTPase RhoA intervient dans de nombreuses fonctions cellulaires au cours du développement, à l'âge adulte et en réponse à diverses agressions. En raison de son expression et ses fonctions, cette protéine est étroitement régulée par plusieurs mécanismes. Dans le chapitre 3, j’ai caractérisé un nouveau mécanisme protéolytique régulant RhoA en réponse au stress cellulaire. J’ai constaté que les fragments générés lors du clivage de RhoA affectent le cytosquelette d'actine en régulant l'assemblage des fibres de stress et des bâtonnets nucléaires. Dans l'ensemble, les résultats de cette thèse nous permettent de mieux comprendre les fonctions de CRMP4 et la régulation de RhoA dans la réponse cellulaire suite aux dommages. Ces découvertes peuvent être extrapolées à d'autres modèles et, ainsi, elle deviennent essentielles à l'identification de nouvelles cibles pour le développement de thérapies qui améliorent la réponse neuronale face à diverses agressions

Psychological Meanings of Eating Disorders and Their Association With Symptoms, Motivation Toward Treatment, and Clinical Evolution Among Outpatients

Unlike patients suffering from egodystonic disorders, people with eating disorders sometimes attribute positive meanings to their symptoms, and this attribution process contributes to the maintenance of the disorder. This study aims at exploring psychological meanings of eating disorders and their associations with symptoms, motivation toward treatment, and clinical evolution. Eighty-one adults with an eating disorder (anorexia nervosa, n = 46 and bulimia nervosa, n = 35) treated in a day-hospital program were asked, each week over an 8-week period, to identify the psychological meanings they ascribed to their eating disorder. Avoidance was the most frequently identified meaning, followed by mental strength, security, death, confidence, identity, care, and communication. Avoidance was more frequently mentioned by participants with bulimia than in cases of anorexia. Security and mental strength were associated with less motivation toward treatment. Death was associated with more depressive and anxious symptoms. An exploratory factor analysis showed that these meanings formed three main dimensions: Avoidance, Intrapsychic, and Relational. Findings suggest that psychological meanings associated with eating disorders can be assessed and used as a clinical tool to increase treatment acceptability and effectiveness

RhoA Proteolysis Regulates the Actin Cytoskeleton in Response to Oxidative Stress.

The small GTPase RhoA regulates the actin cytoskeleton to affect multiple cellular processes including endocytosis, migration and adhesion. RhoA activity is tightly regulated through several mechanisms including GDP/GTP cycling, phosphorylation, glycosylation and prenylation. Previous reports have also reported that cleavage of the carboxy-terminus inactivates RhoA. Here, we describe a novel mechanism of RhoA proteolysis that generates a stable amino-terminal RhoA fragment (RhoA-NTF). RhoA-NTF is detectable in healthy cells and tissues and is upregulated following cell stress. Overexpression of either RhoA-NTF or the carboxy-terminal RhoA cleavage fragment (RhoA-CTF) induces the formation of disorganized actin stress fibres. RhoA-CTF also promotes the formation of disorganized actin stress fibres and nuclear actin rods. Both fragments disrupt the organization of actin stress fibres formed by endogenous RhoA. Together, our findings describe a novel RhoA regulatory mechanism

A Large-Scale Comparison of Canadian Sexual/Gender Minority and Heterosexual, Cisgender Adolescents’ Pornography Use Characteristics

Background The ease of access to pornography has made its use common among adolescents. Although sexual and gender minority (SGM) (eg, gay, transgender) adolescents may be more prone to use pornography owing to sexual orientation–related information seeking and/or scarcity of potential romantic or sexual partners, relatively little attention has been paid to their pornography use and to the quantitative examination of the similarities and differences between heterosexual, cisgender (HC) and SGM adolescents’ pornography use characteristics. Aim The aim of the present study was to compare SGM and HC adolescents’ pornography use considering potential sex differences. Methods We used a sample of 2,846 adolescents (52.5% girls; Mage = 14.5 years, SD = 0.6), which was collected as part of an ongoing longitudinal study on adolescents’ sexual health. Data were analyzed with 5 groups: HC boys; HC girls; SGM boys; SGM girls; and SGM non-binary individuals. Outcomes Adolescents completed a self-report questionnaire about sexual and gender minority status and pornography use (ie, lifetime use, age at first exposure, and frequency of use in the past 3 months.) Results Results indicated significant differences between all groups: 88.2% of HC boys, 78.2% of SGM boys, 54.2% of SGM girls, 39.4% of HC girls, and 29.4% of SGM non-binary individuals reported having ever viewed pornography by the age of 14 years. SGM girls indicated a significantly younger age at first pornography use than HC girls, but this difference was not significant among boys. SGM boys reported the highest (median: many times per week), whereas HC girls reported the lowest (median: less than once a month) frequency of pornography use. Clinical Translation Results suggest that SGM and HC boys' pornography use characteristics are rather similar, whereas SGM and HC girls’ pornography use patterns may be considered different presumably because of the varying underlying motivations (eg, using pornography to confirm sexual orientation). Strengths & Limitations Self-report measures and cross-sectional designs have potential biases that should be considered. However, the present study involved a large sample of adolescents including SGM adolescents, a population group that is understudied. Conclusion Approximately two-thirds of teenagers had gained their first experience with pornography in the present sample, and 52.2% reported using it once a week or more often in the past 3 months, indicating that pornography use may play an important role in both HC and SGM adolescents’ sexual development. Gender-based differences concerning pornography use seem to be robust regardless of SGM status

The molecular interplay between axon degeneration and regeneration

Neurons face a series of morphological and molecular changes following trauma and in the progression of neurodegenerative disease. In neurons capable of mounting a spontaneous regenerative response, including invertebrate neurons and mammalian neurons of the peripheral nervous system (PNS), axons regenerate from the proximal side of the injury and degenerate on the distal side. Studies of Wallerian degeneration slow (Wld(S) /Ola) mice have revealed that a level of coordination between the processes of axon regeneration and degeneration occurs during successful repair. Here, we explore how shared cellular and molecular pathways that regulate both axon regeneration and degeneration coordinate the two distinct outcomes in the proximal and distal axon segments

RhoA fragments and cleavage-resistant promote the formation of actin stress fibres.

<p><b>A)</b> Serum-starved Swiss 3T3 fibroblasts were transfected with Flag-tagged RhoA 1–56 and 57–193, which correspond to RhoA-NTF and -CTF respectively, as well as WT-, Q63L- and the cleavage-resistant L57A/Q63L-RhoA. Cells were stained with anti-Flag M2 antibody (green), Alexa-Fluor 546 phalloidin (red) and Hoechst (blue) to label RhoA, the actin stress fibres and the nucleus respectively. Scale bar, 20 μm. <b>B)</b> Classification of the actin phenotype in transfected Swiss 3T3 cells. Significance was determined by the Chi-square test. *, <i>p</i> < 0.05; ** <i>p</i> < 0.005; ***, <i>p</i> < 0.0005; ****, <i>p</i> < 0.0001. <i>n</i> > 40 cells from 7 independent experiments. <b>C)</b> Quantification of the ratio of actin-covered area divided by the total surface of the transfected cells represented as the mean +/- S.E.M. Significance was established by one-way ANOVA from <i>n</i> > 40 cells collected from 7 independent experiments. *, <i>p</i> < 0.05; ** <i>p</i> < 0.005; ***, <i>p</i> < 0.0005; ****, <i>p</i> < 0.0001. <b>D)</b> Representative side view of a z-stack of a Swiss 3T3 cell overexpressing RhoA-CTF showing the localization of nuclear actin rods (red) relative to the nucleus (blue) and RhoA 57–193 (green). Scale bar, 10 μm.</p

Identification of a 10 kDa amino-terminal RhoA fragment.

<p><b>A)</b> Western blot analysis of COS-7 cell lysates transfected with Flag-tagged WT-RhoA or with 2Xmyc-tagged WT-RhoA using an anti-Flag M2 or anti-c-myc antibody reveals the presence of FL-RhoA and RhoA-NTF bands. <b>B, C)</b> Western blot of cell lysates following treatment with the proteosome inhibitors MG132 <b>(B)</b> or epoxomicin <b>(C)</b>. <b>D)</b> Expression of wild-type (WT), constitutively active (Q63L and G14V), dominant-negative (T19N) as well as non-prenylated wild-type (C190A), active (Q63L/C190A) and inactive (T19N/C190A) RhoA constructs in COS-7 cells analyzed by western blot using the Flag M2 antibody. Western blot panels illustrating FL-RhoA only are exposed to evaluate loading of full-length protein while panels with FL-RhoA and RhoA-NTF are a longer exposure of the same blot to visualize RhoA-NTF.</p

Serine proteases, caspases and calpain regulate RhoA proteolysis.

<p><b>(A-F)</b>. Lysates from COS-7 cells transfected with Flag-tagged WT-RhoA were analyzed by western blot with anti-Flag M2 antibody following treatment with protease inhibitors. Transfected cells were treated for 3h with the serine protease inhibitor AEBSF <b>(A)</b>, 24h hours with the pan-caspase inhibitor z-VAD-fmk <b>(C)</b>, or 3 hours with the calpain inhibitor calpeptin <b>(E)</b> and the levels of RhoA-NTF were quantified by densitometry <b>(B, D, F)</b>. Water and DMSO were vehicle controls. <b>(G-H</b>). 2Xmyc WT-RhoA <b>(G)</b> or Flag RhoA 1–56 <b>(H)</b> were immunoprecipitated from transfected COS-7 cells and treated for 45 minutes with recombinant μ-calpain in the presence or absence of 14 μM calpeptin. <b>I)</b> Diagram illustrating the mechanism underlying RhoA proteolysis.</p

Endogenous RhoA proteolysis is enhanced by oxidative stress.

<p><b>A, B)</b> Lysates from COS-7 cells were transfected with Flag-tagged WT-RhoA <b>(A)</b> or T19N-RhoA <b>(B)</b> and western blotted with anti-Flag M2 antibody. Cells were exposed to H₂O₂ for 1 hour, 24 hours prior to lysis. <b>C)</b> COS-7 cells transfected with Flag-tagged WT-RhoA were immunoprecipitated with the Rho Y486 antibody from Abcam. Lysates and immunoprecipitates were probed with anti-RhoA Y486 or anti-FLAG M2 antibodies. <b>D)</b> Immunoprecipitation of RhoA-NTF from untransfected COS-7 cells treated with H₂O₂ for 1 hour at 24 hour prior to lysis or from various healthy adult rat tissues, including the heart, brain and lungs, using the Rho Y486 antibody. Arrow: RhoA-NTF. <b>E-F)</b> Analysis of the relative abundance of FL-RhoA and RhoA-NTF in cell lysates compared to a dose curve of recombinant WT-RhoA by Western blot analysis with the Rho Y486 antibody. The graph in F quantifies the average concentration of FL-RhoA as well as RhoA-NTF upon treatment with 1000 μM H₂O₂.</p