Melanosomal targeting sequences from gp100 are essential for MHC class II-restricted endogenous epitope presentation and mobilization to endosomal compartments

CD4+ T lymphocytes play an important role in CD8+ T cell-mediated responses against tumors. Considering that about 20% of melanomas express major histocompatibility complex (MHC) class II, it is plausible that concomitant antigenic presentation by MHC class I and class II complexes shapes positive (helper T cells) or negative (regulatory T cells) anti-tumor responses. Interestingly, gp100, a melanoma antigen, can be presented by both MHC class I and class II when expressed endogenously, suggesting that it can reach endosomal/MHC class II compartments (MIIC). Here, we demonstrated that the gp100 putative amino-terminal signal sequence and the last 70 residues in carboxy-terminus, are essential for MIIC localization and MHC class II presentation. Confocal microscopy analyses confirmed that gp100 was localized in LAMP-1+ endosomal/MIIC. Gp100-targeting sequences were characterized by deleting different sections in the carboxy-terminus (residues 590 to 661). Transfection in 293T cells, expressing MHC class I and class II molecules, revealed that specific deletions in carboxy-terminus resulted in decreased MHC class II presentation, without effects on MHC class I presentation, suggesting a role in MIIC trafficking for these deleted sections. Then, we used these gp100-targeting sequences to mobilize the green fluorescent protein (GFP) to endosomal compartments, and to allow MHC class II and class I presentation of minimal endogenous epitopes. Thus, we concluded that these specific sequences are MIIC targeting motifs. Consequently, these sequences could be included in expression cassettes for endogenously expressed tumor or viral antigens to promote MHC class II and class I presentation and optimize in vivo T cell responses, or as an in vitro tool for characterization of new MHC class II epitopes.R.L. is the recipient of a « Fond pour la recherché en santé du Québec » scholarship. This work was supported by grants from the Canadian Institutes of Health Research (CIHR) and from « La fondation du CHUM »

A corpus study of the verbal communication of empathy/sympathy by anglophone nurses in Quebec

When health professionals and patients do not share the same first language, language barriers may exist, which may have negative effects on the quality of communication and health services rendered (e.g. Bowen, 2001). To gain better knowledge of actual language use by nurses for second-language (L2) training purposes, nurse-patient dialogues documented in the Bilingual L2 Training Corpora (BL2TC) (French, 2012) were analysed for the occurrence of eight types of responses used to communicate empathy and/or sympathy. The findings showed that four types of responses (formulating the gist of the trouble, validating, naming feelings and making assessments) were used 90% of the time to communicate empathy/sympathy, whereas the four remaining (expressing one's own feelings, having emotive reactions, reporting one's own reactions and sharing a similar experience) were only used 10% of the time. Moreover, recurring linguistic forms were identified for the more frequent types of responses. RÉSUMÉ Lorsque les infirmières et les patients ne partagent pas une langue maternelle, une barrière linguistique peut se produire et avoir un impact négatif sur la qualité de la communication et des services fournis (p. ex. Bowen, 2001). Pour savoir davantage à propos du langage réel des infirmières pour des fins pédagogiques en L2, le Corpus bilingue pour la formation de L2 (French, 2012) a été analysé pour l'occurrence de huit types de réponses utilisés pour communiquer de l'empathie/la sympathie. Les résultats ont démontré que quatre types de réponses (formuler l'essence de la situation, valider, nommer des sentiments, et quantifier l'ampleur) ont été utilisés 90% du temps, alors que les autres types de réponses (exprimer ses propres sentiments, avoir des réactions émotives, reporter ses réactions, et partager une expérience similaire) n'ont été utilisés que 10% du temps. D'ailleurs, des formes linguistiques récurrentes ont été identifiées pour les types de réponses fréquents

L'effet de la quétiapine sur le phénomène de récompense

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Rôle de la phospholipase A2 de type V dans le recrutement de leucocytes au foyer inflammatoire

Les phospholipases A2 sécrétées (sPLA2) font partie d’une grande famille d’enzymes impliquées dans la synthèse d’écosanoïdes, de chimiokines et dans l’expression de molécules d’adhérence. Ce groupe comprend dix isoformes différentes (sPLA2-IB, -IIA, -IIC, -IID, -IIE, -IIF, -III, -V, -X et XII) dont la majorité sont surexprimées en présence de molécules pro-inflammatoires telles que l’interleukine-1β (IL-1 β) et le lipopolysaccharide bactérien (LPS). La sPLA2-IIA fut longtemps considérée comme la principale sPLA2 associée à l’inflammation. Toutefois, un nombre grandissant d’études suggère l’implication d’autres isoformes dans la réponse inflammatoire. Étant donné la similarité structurelle des différentes isoformes de sPLA2, la majorité des inhibiteurs présentement disponibles sont non spécifiques et bloquent simultanément plus d’une sPLA2. De ce fait, encore peu de choses sont connues quant au rôle précis de chacune des sPLA2 dans la réponse inflammatoire. Ayant accès à des souris génétiquement modifiées n’exprimant pas la sPLA2-V (sPLA2-V-/-), nous avons donc investigué le rôle spécifique de la sPLA2-V dans le recrutement leucocytaire induit par le LPS, ainsi que sa capacité à moduler l’expression de certaines molécules d’adhérence. Pour ce faire, nous avons utilisé le modèle inflammatoire de la poche d’air sous-cutanée. L’administration de LPS dans la poche d’air de souris contrôles (WT) entraîne un recrutement leucocytaire important. Cet appel de cellules inflammatoires est cependant significativement diminué chez les souris sPLA2-V-/-. De plus, l’expression des molécules d’adhérence VCAM-1 et ICAM-1 est également diminuée chez les souris sPLA2-V-/- comparativement aux souris WT. Nos résultats démontrent donc le rôle important de la sPLA2-V dans le recrutement leucocytaire et l’expression de molécules d’adhérence induits par le LPS, confirmant ainsi l’implication de cette enzyme dans le processus inflammatoire.Secretory phospholipases A2 (sPLA2s) are well known for their contribution in the biosynthesis of inflammatory eicosanoids. These enzymes also participate in the inflammatory process by regulating chemokine production and protein expression of adhesion molecules. The majority of sPLA2 isoforms are up-regulated by proinflammatory stimuli such as bacterial lipopolysaccharide (LPS), which predominantly increases the expression of group V sPLA2 (sPLA2-V). Furthermore, it has recently been shown that sPLA2-V is a critical messenger in the regulation of cell migration during allergic airway responsiveness. Herein, we investigated the effect of sPLA2-V on LPS-mediated leukocyte recruitment and its capacity to modulate adhesion molecule expression. We conducted our study in the murine air pouch model, using sPLA2-V null mice (sPLA2-V-/-) and control wild-type (WT) littermates. We observed that LPS (1 μg/mL)-mediated leukocyte migration in sPLA2-V-/- was attenuated by 52 and 86% after 6 and 12 hours of treatment, respectively, as compared to WT mice. In WT mice, treatment with the cell-permeable sPLA2 inhibitor (12-epi-scalaradial; SLD) reduced LPS-mediated leukocyte recruitment by 67%, but had no additional inhibitory effect in sPLA2-V-/- mice. Protein analyses from the air pouch skin were carried out upon LPS-challenge, and the expression of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 were both significantly reduced in sPLA2-V-/- mice as compared to control WT mice. Together, our data demonstrate the role of sPLA2-V in LPS-induced ICAM-1 and VCAM-1 protein overexpression and leukocyte recruitment, supporting the contribution of sPLA2-V in the development of inflammatory innate immune responses

Évaluation des distorsions cognitives et biais de désirabilité sociale chez les agresseurs sexuels d'enfants

Rapport de stage présenté à la Faculté des études supérieures en vue de l'obtention du grade de Maitre ès sciences (M.Sc.) en criminologie option interventionÀ première vue, les outils d’évaluation des distorsions cognitives chez les agresseurs sexuels d’enfants sont valides et fidèles. Pourtant, chaque outil reçoit la critique d’être sujet au biais de désirabilité sociale. En effet, il semblerait que les individus ayant agressé sexuellement des enfants auraient tendance à vouloir se présenter sous un meilleur jour en modifiant leurs réponses aux outils d’évaluation. Malgré cela, les outils semblent en mesure de discriminer significativement les cognitions de ces individus. Comment est-ce possible? La présente recherche avait pour objectif de déterminer, par une recension systématique des écrits, si les outils d’évaluation des distorsions cognitives réussissent efficacement à discriminer les cognitions des agresseurs sexuels d’enfants malgré les problèmes de désirabilité sociale qui leur sont inférés. Par le fait même, cette étude voulait offrir une meilleure compréhension théorique de l’évaluation des cognitions des agresseurs sexuels d’enfants, ainsi que de l’utilité et de la pertinence clinique des outils d’évaluation. Les résultats obtenus indiquent que les outils permettent une discrimination efficace des cognitions des agresseurs sexuels d’enfants malgré la critique faisant état d’un biais de désirabilité sociale. Cependant, en observant de plus près les résultats, il est possible de constater que les agresseurs d’enfants sont majoritairement en désaccord avec les items des outils d’évaluation. Jadis, ces résultats étaient justifiés par la présence d’un biais de désirabilité sociale. Il se trouve que cette conclusion n’est que peu appuyée par la littérature et que la désirabilité sociale ne jouerait qu’un faible rôle dans l’analyse des résultats obtenus, sans les invalider. En dernier lieu, il semble également que les agresseurs sexuels d’enfants répondraient honnêtement aux questionnaires et ne chercheraient pas à camoufler leurs réelles croyances.At first glance, the assessment tools for cognitive distortions in child molesters seem valid and reliable. These tools are however critiqued for being associated with a social desirability bias as child molesters seemingly tend to modulate their answers to show the best of themselves. Despite this, it seems that the assessment tools can achieve a significative discrimination of child molesters’ cognitions. How is this possible? For the purpose of this research paper, we conducted a literature review to determine whether the cognitive distortions assessment tools can allow for an effective discrimination of child molesters’ cognitions despite the social desirability issues they are attributed. We also aimed to achieve a better theoretical understanding of the assessment of child molesters’ cognitions as well as of the usefulness and clinical relevance of the assessment tools. Our results indicate that, despite the criticism formulated about a presumed social desirability bias, the assessment tools do allow for an effective discrimination of child molesters’ cognitions. However, upon closer inspection, it is possible to note that child molesters mostly disagree with the assessment tools items. Although these results were once attributed to the presence of a social desirability bias, we could find little support of this conclusion in the literature as social desirability only seemed to play a minimal role in the analysis of the assessment tools results without rendering them invalid. Lastly, it seems that child molesters honestly answer the assessment tools questions without trying to dissimulate the beliefs they really hold

HIF2α reduces growth rate but promotes angiogenesis in a mouse model of neuroblastoma

<p>Abstract</p> <p>Background</p> <p>HIF2α/EPAS1 is a hypoxia-inducible transcription factor involved in catecholamine homeostasis, vascular remodelling, physiological angiogenesis and adipogenesis. It is overexpressed in many cancerous tissues, but its exact role in tumour progression remains to be clarified.</p> <p>Methods</p> <p>In order to better establish its function in tumourigenesis and tumour angiogenesis, we have stably transfected mouse neuroblastoma N1E-115 cells with the native form of HIF2α or with its dominant negative mutant, HIF2α (1–485) and studied their phenotype <it>in vitro </it>and <it>in vivo</it>.</p> <p>Results</p> <p><it>In vitro </it>studies reveal that HIF2α induces neuroblastoma cells hypertrophy and decreases their proliferation rate, while its inactivation by the HIF2α (1–485) mutant leads to a reduced cell size, associated with an accelerated proliferation. However, our <it>in vivo </it>experiments show that subcutaneous injection of cells overexpressing HIF2α into syngenic mice, leads to the formation of tumour nodules that grow slower than controls, but that are well structured and highly vascularized. In contrast, HIF2α (1–485)-expressing neuroblastomas grow fast, but are poorly vascularized and quickly tend to extended necrosis.</p> <p>Conclusion</p> <p>Together, our data reveal an unexpected combination between an antiproliferative and a pro-angiogenic function of HIF2α that actually seems to be favourable to the establishment of neuroblastomas <it>in vivo</it>.</p

Disruption of AP1S1, Causing a Novel Neurocutaneous Syndrome, Perturbs Development of the Skin and Spinal Cord

Adaptor protein (AP) complexes regulate clathrin-coated vesicle assembly, protein cargo sorting, and vesicular trafficking between organelles in eukaryotic cells. Because disruption of the various subunits of the AP complexes is embryonic lethal in the majority of cases, characterization of their function in vivo is still lacking. Here, we describe the first mutation in the human AP1S1 gene, encoding the small subunit σ1A of the AP-1 complex. This founder splice mutation, which leads to a premature stop codon, was found in four families with a unique syndrome characterized by mental retardation, enteropathy, deafness, peripheral neuropathy, ichthyosis, and keratodermia (MEDNIK). To validate the pathogenic effect of the mutation, we knocked down Ap1s1 expression in zebrafish using selective antisens morpholino oligonucleotides (AMO). The knockdown phenotype consisted of perturbation in skin formation, reduced pigmentation, and severe motility deficits due to impaired neural network development. Both neural and skin defects were rescued by co-injection of AMO with wild-type (WT) human AP1S1 mRNA, but not by co-injecting the truncated form of AP1S1, consistent with a loss-of-function effect of this mutation. Together, these results confirm AP1S1 as the gene responsible for MEDNIK syndrome and demonstrate a critical role of AP1S1 in development of the skin and spinal cord

A corpus study of the verbal communication of empathy/sympathy by Anglophone nurses in Quebec

Lorsque les infirmières et les patients ne partagent pas une langue maternelle, une barrière linguistique peut se produire et avoir un impact négatif sur la qualité de la communication et des services fournis (p. ex. Bowen, 2001). Pour savoir davantage à propos du langage réel des infirmières pour des fins pédagogiques en L2, le Corpus bilingue pour la formation de L2 (French, 2012) a été analysé pour l'occurrence de huit types de réponses utilisés pour communiquer de l’empathie/la sympathie. Les résultats ont démontré que quatre types de réponses (formuler l'essence de la situation, valider, nommer des sentiments, et quantifier l'ampleur) ont été utilisés 90% du temps, alors que les autres types de réponses (exprimer ses propres sentiments, avoir des réactions émotives, reporter ses réactions, et partager une expérience similaire) n’ont été utilisés que 10% du temps. D’ailleurs, des formes linguistiques récurrentes ont été identifiées pour les types de réponses fréquents.When health professionals and patients do not share the same first language, language barriers may exist, which may have negative effects on the quality of communication and health services rendered (e.g. Bowen, 2001). To gain better knowledge of actual language use by nurses for second-language (L2) training purposes, nurse-patient dialogues documented in the Bilingual L2 Training Corpora (BL2TC) (French, 2012) were analysed for the occurrence of eight types of responses used to communicate empathy and/or sympathy. The findings showed that four types of responses (formulating the gist of the trouble, validating, naming feelings and making assessments) were used 90% of the time to communicate empathy/sympathy, whereas the four remaining (expressing one’s own feelings, having emotive reactions, reporting one’s own reactions and sharing a similar experience) were only used 10% of the time. Moreover, recurring linguistic forms were identified for the more frequent types of responses

Identification of a glucan synthase gene potentially coding for exopolysaccharide production by Propionibacterium freudenreichii subsp. shermanii

International audienceA gene potentially coding for exopolysaccharide (EPS) biosynthesis was identified in the genome sequence of Propionibacterium freudenreichii subsp. shermanii strain CIP 103027. The predicted protein product of this gene, designated Pps, best aligned with Tts, a polysaccharide synthase gene of Streptococcus pneumoniae type 37, which is responsible for the production of a glucan capsular polysaccharide. Pps also showed similarity with the putative glucan synthase Dps of Pediococcus damnosus and Oenococcus oeni. Specific primers were designed in order to detect the presence of pps in other P. freudenreichii subsp. shermanii strains by PCR amplification using total genomic DNA. The gene was detected in all the 12 strains tested. The same primers failed to detect the gene in an EPS-producing strain of Propionibacterium acidipropionicii, suggesting that the gene is not present or is sufficiently divergent in sequence to prevent amplification. Pps gene was totally sequenced for 8 strains, and seems to be very conserved, as less than 1 % of nucleotides differed from one strain to another. In order to evaluate pps gene expression, total RNA of 3 strains was extracted at different growth phases in YEL broth. The presence of mRNA corresponding to the gene was detected by RT-PCR in all 3 strains during exponential and stationary growth phases. This work is the first identification of a polysaccharide synthase gene of P. freudenreichii, and further studies need to be undertaken to measure the variability among strains in the production of capsular EPS