Orientadores: Henrique Marques Barbosa de Souza, Carla Beatriz Collares Buzato / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-25T12:54:45Z (GMT). No. of bitstreams: 1 Hernandes_LeticiaHelenaPinto_M.pdf: 22200442 bytes, checksum: 95e81ba6b7934db5b7e01d5eea75202c (MD5) Previous issue date: 2014 / Resumo: O Diabetes Mellitus tipo 2 (T2DM) representa uma das principais doenças do mundo moderno, e é caracterizado pelo comprometimento da homeostase glicêmica do organismo, resultante de uma combinação da redução da sensibilidade periférica à insulina e o comprometimento da função das células-'beta'. Estudos recentes sugerem que Coup-TFII possui um papel importante na homeostase glicêmica e no metabolismo energético. Apesar destes trabalhos representarem fortes indícios, ainda é desconhecido se Coup-TFII desempenharia este papel modulador da homeostase glicêmica e do metabolismo energético em indivíduos com T2DM. O objetivo deste trabalho foi investigar o padrão de expressão de Coup-TFII em camundongos apresentando um quadro pré-diabético. Para isto, foram utilizados camundongos C57BL/6 tipo selvagem tratados com dieta hiperlipídica (dHL) por 60 dias (animais dHL). A caracterização metabólica revelou que estes animais apresentaram características de quadro pré-diabético, i.e., sobrepeso, resistência periférica à insulina associada à moderada hiperglicemia, significativa hiperinsulinemia (resultante da hiperplasia compensatória de células-'beta') e distúrbios na secreção de insulina, tanto no estado basal (2,8 mM de glicose), quanto em condição estimulatória (16,8 mM de glicose). A análise da expressão de Coup-TFII por qPCR revelou uma redução dos níveis transcricionais deste gene em ilhotas dos animais dHL. Estes resultados indicam que a relação negativa previamente demonstrada entre hiperglicemia, hiperinsulinemia e reduzida secreção de insulina e a expressão de Coup-TFII também ocorre no quadro pré-diabético desenvolvido pelos animais dHL. Interessantemente, análise do conteúdo proteico de Coup-TFII revelou um aumento significativo de 33,6% nos animais dHL, resultado que contrasta com a redução da transcrição deste gene nas células-'beta' destes animais. Uma possível explicação seria pelo papel fundamental que Coup-TFII exerce no processo de proliferação das células-'beta' dependente da via Wnt/'beta'-catenina, observada durante o desenvolvimento e potencialmente atuando na hiperplasia compensatória nos animais dHL. Além disso, trabalhos recentes demonstraram que Coup-TFII atua como um regulador negativo de sua própria transcrição em células-'beta'. Portanto, com 60 dias de tratamento o quadro de hiperplasia nos animais dHL demandaria maiores níveis da proteína de Coup-TFII em comparação com os animais Ctr. Uma vez elevado, este nível proteico de Coup-TFII, juntamente com os efeitos das alterações metabólicas, teriam um efeito negativo sobre a transcrição de Coup-TFII nos animais dHL / Abstract: Type 2 diabetes mellitus (T2DM) is one of the most important diseases in the modern world, and is characterized by the compromise of the glycemic homeostasis and a result of a combination of insulin resistance and impaired 'beta'-cell function. Recent studies show that nuclear receptor COUP- TFII (Chicken ovalbumim upstream promoter transcription factor II) plays an important role in regulating glycemic homeostasis and energy metabolism. Although these results are a strong hint, it is still unknown whether Coup-TFII would have a role modulating glycemic homeostasis and energy metabolism in individuals suffering from T2DM. The aim of this work was to investigate the expression pattern of the transcription factor Coup-TFII in mice displaying pre-diabetic condition. To this aim, C57BL/6, wildtype mice were treated with high fat diet (dHL, from the Portuguese dieta hiper lipídida) for 60 days (dHL mice). Metabolic characterization confirmed that dHL mice display characteristics of pre-diabetic condition, i.e., overweigh, insulin resistance associated with moderate hyperglycemia, hyperinsulinemia (as a result of hyperplasia of 'beta'-cells) and impaired insulin secretion both, in basal and high blood glucose concentrations. Gene expression analysis for Coup-TFII by qPCR revealed a significant reduction of its transcripts in pancreatic islet of dHL animals. These results indicate that the previously described negative relationship between hyperglycemia, hyperinsulinemia and imparted insulin secretion and Coup-TFII expression is also happening in the pre-diabetic condition developed by dHL animals. Interestingly, analysis of the protein expression of Coup-TFII reveled a significant increase of 33,6% in dHL animals, a result that the contrasts with the reduction of Coup-TFII transcripts observed in these animals. One possible explanation is the essential role that Coup-TFII plays in the Wnt/'beta'-catenin-dependent 'beta'-cell proliferation, in addition to the negative feedback loop observed in 'beta'-cells for Coup-TFII on its own expression. By 60 days of treatment, 'beta'-cell proliferation during hyperplasia in dHL animals would require levels of Coup-TFII protein higher then in control animals. Once increased, this higher protein level, in addition to the metabolic alterations, would have a negative effect on Coup-TFII transcription in dHL animals / Mestrado / Biologia Celular / Mestre em Biologia Celular e Estrutural

Cette thèse porte sur l’opinion publique et la démocratie. Elle s’intéresse particulièrement aux Guatémaltèques et à leur faible propension à appuyer la démocratie et certains des principes associés à celle-ci. Entre des explications qui associent ce comportement à un artéfact et à une culture autoritaire, des éléments contextuels et d’importantes nuances prévalent. Ce travail montre qu’il est nécessaire de traiter l’appui à la démocratie comme un objet multiface et malléable. En puisant dans les théories des perspectives et des bifurcations, un instrument d’analyse est élaboré sous le libellé de « temps court de l’appui à la démocratie ». Ce dernier nous permet de comprendre pourquoi, en période de crise politique, les points de vue sur la démocratie sont susceptibles d’évoluer. Sensibles aux circonstances extraordinaires, les opinions peuvent aussi, dans des périodes plus calmes, connaître une certaine stabilité. Les théories de l’ambivalence permettent d’élaborer un deuxième instrument, le « temps long de l’appui à la démocratie », qui aide à expliquer pourquoi les sondés offrent souvent des réponses « contradictoires » en matière de droits et de libertés. Aussi ambivalents que les autres Centraméricains, les Guatémaltèques se démarquent cependant par une forte tendance à esquiver les questions de sondage, à s’opposer aux droits des gens qui critiquent le gouvernement et à évaluer négativement le travail des institutions. Ces caractéristiques mettent en lumière des tensions entre les demandes et l’évaluation de l’offre en démocratie que font les citoyens. Cette thèse débute en étudiant les dimensions de la culture politique guatémaltèque et en proposant une typologie des indicateurs employés dans les grandes enquêtes internationales. / This thesis deals with public opinion and democracy. It mainly focuses on Guatemalans and on their weak propensity to support democracy and some of its dimensions. Between explanations that tie this behaviour to an artifact and to a culture of authoritarianism, contextual factors and important nuances can be found. We thus argue that it is advisable to deal with support for democracy as a multifaceted and malleable object. Drawing from perspectives and bifurcation theories, we develop an analytical instrument that we refer to as the "short-run of support for democracy". The latter allows us to understand why and how, in times of crisis, citizens’ viewpoints on democracy can easily become volatile. The fact that opinions are sensitive to extraordinary circumstances does not prevent them, under usual circumstances, from being relatively stable. Building on theories on ambivalence, we elaborate another instrument, the "long-run of support for democracy", which allows us to explain why survey respondents often give "contradictory" answers to questions dealing with rights and freedoms. While as ambivalent as other Central Americans, Guatemalans stand apart for their likelihood to avoid certain survey questions, to prefer limiting the rights of people who criticize the government, and to be particularly distrustful of state institutions. As background to those opinions and other paradoxical attitudes, we highlight existing tensions between citizens’ demands and their evaluation of the offer in democracy. This thesis first examines the various dimensions of the Guatemalan political culture and proposes a typology of indicators used in international barometer surveys.

Depuis plusieurs années, un nombre non négligeable d’Etats africains, sont confrontés à la problématique de la remise en cause des acquis démocratiques. Aussi, en 2008, l’actualité politique de la Mauritanie et la Guinée est-elle secouée par les coups d’Etat qui ont lieu respectivement en août et décembre. Au fil des jours qui s’égrènent, ces deux Etats entrent dans une crise politique avec un air de guerre larvé. La communauté internationale porte une attention particulière à l’évolution de ces derniers, d’autant plus qu’ils font partie, pour la Mauritanie, de la zone sahélosaharienne, et pour la Guinée, de la sous-région ouest-africaine, deux espaces géographiques en proie à l’instabilité. Ainsi, conformément aux dispositions prévues par le droit international, la communauté internationale au nom desquelles l’Union Africaine, la CÉDÉAO, la France et les Etats-Unis, s’implique afin de conduire le processus de sortie de crise dans chaque pays. La présente thèse investit de ce fait les contours de cet interventionnisme étranger, tout en mettant en lumière les facteurs déclencheurs sousjacent de ces deux crises politiques. Ce faisant, nous examinons les principes et enjeux fondamentaux régissant cette ingérence. Une dynamique qui, dans sa globalité, permet d’apprécier les postures contrastées adoptées par les acteurs étrangers face à chaque putschiste / Over many years, numerous African States are facing serious issues due to the reappraisal or challenges of their so called democratic political system. Also, in the year 2008, the existing political conditions in both Mauritania and Guinea were destroyed by a coup d'état known as coup (e.g., putsch, or an overthrow), respectively in August and December of the same year; And over the days, these two states entered into political crisis considered as implying actions to be taken or steps toward civil war. The international community is highly considering these above mentions two states, for they are respectively parts the very geographical spaces threatened by constant instability such as the Sahel-Saharan zone (e.g., Mauritania) and the west-African sub-region (e.g., Guinea). In accordance with regulations and provisions by international law, we could acknowledge the involvement of the international community amongst the African Union, the Economic Community of West African States (ECOWAS), France and the United States, in order to lead the post-crisis process in each country. This thesis endeavors to investigate all the aspects with respect of these foreign interventionists, while highlighting the factors that trigger off these two political crises. Meanwhile, this thesis contributes to examine the principles and fundamental stakeholders of this external interference from these countries. Hence, the overall system, allows understanding the versatility of external forces or foreign actors standing out each coup d'état or "stroke of state"

Orientador: Henrique Marques Barbosa de Souza / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T10:31:42Z (GMT). No. of bitstreams: 1 Rosa_VivianedeSouza_M.pdf: 2727894 bytes, checksum: d0d5ab88ca9670f3109f39586f01a78c (MD5) Previous issue date: 2015 / Resumo: Células-tronco embrionárias (CTE) são células indiferenciadas que possuem a capacidade de (1) se proliferarem indefinidamente (auto-renovação) e, quando induzidas, (2) darem origem a qualquer tipo celular presente no embrião (pluripotência). Uma das abordagens mais comumente utilizadas para o estudo de diferenciação de CTE é através da formação de agregados multicelulares esféricos denominados corpos embrióides (CE). CE passam por um processo de morfogênese semelhante ao observado em embriões, originando derivados dos três folhetos germinativos. Durante o desenvolvimento embrionário, a formação e o posicionamento dos três folhetos ocorre por um processo altamente coordenado que culmina na formação de um embrião polarizado no eixo anteroposterior. Entretanto, um dos grandes desafios de pesquisas que envolvem o uso da diferenciação de CTE em CE é encontrar indícios de que esses processos são recapitulados in vitro e se entender como que células derivadas dos folhetos germinativos, que no embrião ocorrem de forma altamente organizada, são originadas em estruturas celulares sem nenhuma organização global evidente, como visto em CE. Coup-TFII (Chicken ovalbumin upstream promoter-transcription factor II) é um fator de transcrição o qual possui um papel fundamental na regulação do desenvolvimento embrionário e na aquisição de destinos celulares específicos durante a diferenciação de CTE. Utilizando CE como um modelo de estudo, caracterizamos a expressão de Coup-TFII e seu possível envolvimento durante a determinação de destinos celulares. Nossos resultados identificaram uma expressão hemisférica de Coup-TFII em CE em etapas inicias do processo de diferenciação. Esta observação nos levou a caracterizar a distribuição espacial de marcadores moleculares tecido-específicos nos CE em relação à expressão hemisférica de Coup-TFII. Interessantemente, praticamente todas as células identificadas como precursores mesodérmicos e precursores neuroectodérmicos, através da expressão de Brachyury-T e Nestin, respectivamente, estão contidas nas população de células Coup-TFII-positivas. Estes resultados sugerem a existência de um mecanismo de organização global intrínseco nas CTE, onde a expressão de Coup-TFII parece segregar os CE em dois hemisférios e, provavelmente de forma antagônica com Oct4, determinaria diferentes destinos celulares ainda em fases iniciais da diferenciação / Abstract: Embryonic stem cells (ESC) are undifferentiated cells that have the ability to (1) proliferate indefinitely (self-renewal) and when induced, (2) give rise to any cell type present in the embryo (pluripotency). One of the most commonly used approaches for the study of ESC differentiation is through the formation of spherical multicellular aggregates called embryoid bodies (EB). EB undergo a process similar to that observed in morphogenesis embryos, giving derivatives of three germ layers. During embryonic development, formation and placement of the three germ layers is a highly coordinated process by which culminates in the formation of a polarized embryo in the antero-posterior axis. However, one of the great challenges of research involving the use of ESC differentiation in EB is to find evidence that these processes are recapitulated in vitro and in understanding how to cells derived from the germ layers that occurs in the embryo highly organized manner originate on cellular structures with no apparent global organization, as seen in the EB. COUP-TFII (chicken ovalbumin promoter-upstream transcription factor II) is a transcription factor which plays a key role in the regulation of embryonic development and determination of specific cell fates during differentiation ESC. Using EB as a model system, we characterized the expression of Coup-TFII and its possible involvement in the determination of cell fates. Our results identified a hemispheric expression of Coup-TFII in EB at the onset of differentiation. This observation led us to characterize the spatial distribution of tissue-specific molecular markers in EB in relation the hemispheric expression of Coup-TFII. Interestingly, practically all cells identified as mesodermal and neuroectodermal precursors by the expression of Brachyury-T and Nestin, respectively, are contained in the COUP-TFII-positive cell population. These results suggest the existence of a mechanism of global organization intrinsic to ESC, where the expression of Coup-TFII segregates the EB into two hemispheres and probably antagonistically with Oct4, determine different cell fates still in early stages of differentiation / Mestrado / Biologia Tecidual / Mestra em Biologia Celular e Estrutural

Arteriosklerose führt zu schwerwiegenden klinischen Komplikationen bei Herz-Kreislauf-erkrankungen, welche die führenden Todesursachen in den westlichen Industrieländern sind. Die Arteriosklerose ist typischerweise eine Erkrankung arterieller Gefäße und betrifft nicht die venöse Gefäßwand. Bei der Entstehung von Arteriosklerose spielen die Endothelzellen als Barrierezellen und Regulatoren der Gefäßfunktion eine Schlüsselrolle. Ein wichtiger Schwerpunkt der Forschung ist die Differenzierung der Endothelzellen. Arterielle und venöse Endothelzellen weisen schon im frühen Embryonalstadium unterschiedliche Phänotypen auf. Ein besseres Verständnis der arterio-venösen Differenzierung wäre von großer Bedeutung für antiarteriosklerotische Therapien. Darüber hinaus könnte eine Reprogrammierung (z.B. von Vene in Arterie) entscheidend für neue Therapieansätze bei der Senkung der Restenoserate venöser Bypässe von Patienten mit koronarer Herzkrankheit und bei AV-Shunt-Operationen von dialysepflichtigen Patienten sein. In dieser Arbeit wurden differenzierte humane primäre arterielle und venöse Endothelzellen nach Genmodulation untersucht. Der Fokus der Genmodulation wurde auf das arterielle Markergen Hey2 und auf das venöse Markergen COUP-TFII gelegt. Das arterielle Markergen Hey2 ist ein Zielgen der Notch-Signalkaskade, während der molekulare Mechanismus der Rolle von COUP-TFII bei der venösen Differenzierung noch nicht bekannt ist. Daher wurde der Einfluss des arteriellen Markergens Hey2 und des venösen Markergens COUP-TFII auf die Notch-Signalkaskade untersucht, um ein besseres Verständnis über die molekularen Mechanismen der arterio-venösen Differenzierung zu gewinnen. Da humane primäre Endothelzellen mit kommerziell verfügbaren Transfektionsmitteln schwer transfizierbar sind, wurde zunächst ein lentivirales Vektorsystem etabliert. Hiermit wurde eine erfolgreiche und stabile Genexpression bzw. Genrepression in arteriellen und venösen Endothelzellen ermöglicht. Die Genmodulationen in arteriellen Endothelzellen, die durch die Expression des venösen Markergen COUP-TFII bzw. durch die Repression des arterellen Markergen Hey2 verursacht wurden, führten zu der neuen Erkenntnis, dass das venöse Markergen COUP-TFII in arteriellen Endothelzellen als ein Repressor des arteriellen Markergens Hey2 fungiert. Diese Repression wird durch eine direkte Bindung von COUP-TFII an den Hey2-Promotor vermittelt. Die COUP-TFII Expression bewirkte keine Veränderung in der Expression von Notch4, Dll4 und Nrp1. Dies könnte bedeuten, dass (i) COUP-TFII in arteriellen Endothelzellen kein Regulator von diesen Genen ist, (ii) Kooperationspartner von COUP-TFII fehlen, die in arteriellen Endothelzellen nicht vorhanden sind, oder (iii) der molekulare Mechanismus dieser Gene aufgrund seiner wichtigen Rolle nicht durch die Modifikation eines einzigen Gens beeinflussbar ist, da die Gene der Notch-Signalkaskade redundant kontrolliert werden. In venösen Endothelzellen wurden Genmodulationen durch Expression des arteriellen Markergens Hey2 bzw. durch die Repression des venösen Markergens COUP-TFII durchgeführt. Eine Expression des arteriellen Markergens Hey2 in venösen Endothelzellen konnte nicht die Expression der Gene der Notch-Signalkaskade aktivieren. Dies bedeutet, dass die Regulation dieser Gene durch einen übergeordneten molekularen Mechanismus gesichert ist. Interessanterweise konnte die Expression von Hey2 eine Reduktion der Hey1 Expression bewirken. Dies ist ein alternativer Effekt von Hey2 im Vergleich zu arteriellen Endothelzellen. Eine Repression des venösen Markergens COUP-TFII konnte die Expression der Gene Dll4, EphrinB2 und EphB4 induzieren. Vermutlich ist die Induktion der EphB4 Expression ein Kompensationsmechanismus auf die reduzierte COUP-TFII Expression. COUP-TFII sichert den venösen Phänotyp wahrscheinlich durch die Repression von EphrinB2 und Dll4, wobei die Reduktion von Dll4 vermutlich eine größere Bedeutung hat. Da Dll4 ein Ligand und Aktivator der Notch-Signalkaskade ist, ist seine Repression entscheidend für venöse Endothelzellen. Das arterielle Markergen Hey2 ist für die normale Embryogenese von großer Bedeutung, jedoch ist Hey2 als eines der Zielgene der Notch-Signalkaskade wahrscheinlich nicht in der Lage, molekulare Mechanismen, die zu unterschiedlichen endothelialen Phänotypen führen, zu aktivieren. Um arterielle Endothelzellen zu einem Reprogramming zu bewegen, wären wahrscheinlich Genmodulationen der Mitglieder der Notch-Signalkaskade, die upstream von Hey2 liegen, nötig. Hingegen ist die Rolle des venösen Markergens COUP-TFII in der Regulation der arterio-venösen Differenzierung von entscheidender Bedeutung. COUP-TFII spielt eine direkte Rolle in der Aufrechterhaltung der venösen Identität. Die Repression von COUP-TFII in venösen Endothelzellen bewirkt, dass sich die Expression des Gens Dll4, das die Notch-Signalkaskade aktiviert, in Richtung des arteriellen Expressionsniveaus bewegt. Für eine Reprogrammierung der venösen Endothelzellen in einen arteriellen Phänotyp ist das venöse Markergen COUP-TFII eines der Zielgene.

Ο μεταγραφικός παράγοντας COUP-TF είναι ένας ορφανός πυρηνικός υποδοχέας, ο οποίος είναι πολύ σημαντικός κατά την εμβρυική ανάπτυξη. Στην παρούσα εργασία επιχειρήθηκε η μελέτη του φυσιολογικού ρόλου του COUP-TFII των θηλαστικών κατά την αναγέννηση του σκελετικού μυός, χρησιμοποιώντας ως μοντέλο διαφοροποίησης τη μυοβλαστική σειρά ποντικού C2C12, που προέρχεται από ενήλικα βλαστικά κύτταρα του ίδιου μυός. Ο mCOUP-TFII εμπλέκεται στη ρύθμιση της ανάπτυξης του καρδιαγγειακού συστήματος, της μυογένεσης και άλλων αναπτυξιακών διαδικασιών. Έχει δειχθεί ότι αναστέλλει τη διαφοροποίηση των μυοβλαστών C2C12 σε μυοσωλήνες, κυρίως μέσω καταστολής της έκφρασης των μεταγραφικών παραγόντων μυογένεσης MyoD και Myogenin. Επίσης, η έκφρασή του στους μυοβλάστες C2C12 καταστέλλεται με την έναρξη της διαφοροποίησης. Αδημοσίευτα αποτελέσματα του εργαστηρίου μας, έχουν δείξει ότι μέσω εναλλακτικού ματίσματος στο mRNA του PlCOUP-TF του αχινού προκύπτουν δύο ισομορφές του υποδοχέα που διαφέρουν ως προς ένα εξώνιο 21 αμινοξέων στην DBD. H μικρή ισομορφή είναι λειτουργικός μεταγραφικός παράγοντας και δρα ως ομοδιμερές, ενώ η μεγάλη ισομορφή και τα ετεροδιμερή των δυο ισομορφών εμφανίζουν αδυναμία πρόσδεσης στο DNA. Με αυτόν τον τρόπο, η μεγάλη ισομορφή ρυθμίζει την ποσότητα του λειτουργικού μεταγραφικού παράγοντα, δρώντας ως επικρατής κατασταλτική πρωτεΐνη. Αρχικά, μελετήθηκαν οι ιδιότητες πρόσδεσης του mCOUP-TFII και η δυνατότητα σχηματισμού ετεροδιμερών με τη μεγάλη ισομορφή του PlCOUP-TF (L.I.) μέσω δοκιμής in vitro πρόσδεσης (EMSA), δεδομένης της ικανότητας ετεροδιμερισμού του hCOUP-TFI με την ομόλογη πρωτεΐνη του αχινού. Βρέθηκε ότι ο mCOUP-TFII δύναται να προσδεθεί στο στοιχείο απόκρισης C1R με τη μορφή ομοδιμερών και έχει ικανότητα ετεροδιμερισμού με τη PlCOUP-TF L.I. Τα ομοδιμερή του mCOUP-TFII εμφάνιζαν μειούμενη πρόσδεση στο DNA, όσο αυξανόταν ο λόγος PlCOUP-TF L.I./mCOUP-TFII. Ο απώτερος στόχος της έρευνας ήταν η μελέτη του ρόλου του mCOUP-TFII στη μυϊκή διαφοροποίηση, μέσω της υπερέκφρασης της επικρατούς κατασταλτικής PlCOUP-TF L.I. σε καλλιέργειες κυττάρων C2C12. Η αρχική μας υπόθεση ήταν ότι η PlCOUP-TF L.I. δύναται να δράσει ως επικρατής κατασταλτική ισομορφή του mCOUP-TFII, μέσω σχηματισμού μη λειτουργικού ετεροδιμερούς μαζί του. Σε αυτή την περίπτωση, θα αναμενόταν η PlCOUP-TF L.I. να καταστείλει τη δράση του ενδογενούς mCOUP-TFII των κυττάρων C2C12, με αποτέλεσμα την επαγωγή της διαφοροποίησης των μυοβλαστών. Αντιθέτως, η υπερέκφραση του mCOUP-TFII, θα αναμενόταν να συντελέσει στη διατήρηση της αδιαφοροποίητης κατάστασης των μυοβλαστών. Δεν παρατηρήθηκε διαφορά στις δράσεις των δυο COUP-TFs, ωστόσο, από τα πειράματα αυτά δεν μπορεί να εξαχθεί κάποιο ασφαλές συμπέρασμα αναφορικά με το ρόλο του mCOUP-TFII στη διαφοροποίηση των μυοβλαστών και τη δυνατότητα in vivo αλληλεπίδρασης μεταξύ των δυο υποδοχέων. / The transcription factor COUP-TF is an orphan nuclear receptor, which is very important during embryonic development. In the present dissertation, we attempted to study the physiological role of mammalian COUP-TFII during skeletal muscle regeneration, by use of the myoblast cell line C2C12, which originates from adult stem cells of skeletal muscle, as a model system of cell differentiation. mCOUP-TFII is involved in the regulation of cardiovascular system development, myogenesis and other developmental processes. It has been shown to inhibit the differentiation of C2C12 myoblasts to myotubes, mainly through suppression of the myogenic regulatory factors MyoD and Myogenin gene expression. Moreover, its expression in C2C12 myoblasts is suppressed at the onset of differentiation. Alternative splicing of the sea urchin PlCOUP-TF mRNA results in two isoforms, which differ by a 21 aa insertion in the DBD (unpublished data). The small isoform is a functional transcription factor that acts as a homodimer, while the large isoform and the heterodimers of the two isoforms fail to bind DNA. In this way, the large isoform regulates quantitatively the functional transcription factor, acting as dominant negative protein. Initially, by using in vitro binding assays (EMSA), we studied the binding properties of mCOUP-TFII and the possibility of forming heterodimers with the large isoform of PlCOUP-TF (L.I.), provided that hCOUP-TFI has been reported to be able to heterodimerize with the sea urchin homologue. We found that mCOUP-TFII is capable of binding the C1R response element as a homodimer and of forming heterodimers with PlCOUP-TF L.I. The binding of mCOUP-TFII homodimers has been shown to reduce as the ratio PlCOUP-TF L.I./mCOUP-TFII increases. The ultimate goal of this research, was the study of the role of mCOUP-TFII in muscle differentiation via overexpression of the dominant negative PlCOUP-TF L.I. in C2C12 cell cultures. Our initial assumption was that PlCOUP-TF L.I. is capable of acting as a dominant negative isoform of mCOUP-TFII, by forming non functional heterodimers with it. In this case, PlCOUP-TF L.I. would be expected to suppress the action of endogenous mCOUP-TFII in C2C12 cells. In contrast, overexpression of mCOUP-TFII would be expected to contribute to the maintenance of myoblasts in an undifferentiated state. We did not observe any difference in the actions of the two COUP-TFs, however, we cannot report any result regarding either the role of mCOUP-TFII in myoblast differentiation or the ability of in vivo interaction between these receptors.

.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

This study aims to describe and compare the differences and similarities for US mainstream media’s representation of two different coup attempts by using Robert Entman’s Framing theory in terms of legitimacy. The chosen cases are the coup attempt in Turkey (2016) which is an US ally, having a right-wing government and the coup attempt in Venezuela (2002) which has a strained relationship with the US and having left-wing government. The research applies qualitative approach to conduct a small-n case study for comparing and analyzing how the media framed the legitimacy of acts and actors during these two coup attempts. This is an attempt to describe the problematization of theory becoming practice for the US mainstream media regarding the presentation of what is legitimate and what is not. The definition of legitimacy is very clear, but the US mainstream media have issues to reflect this definition to the reality.

Em 1964, ao menos três IPMs foram instaurados em unidades da Universidade de São Paulo, com o objetivo de apurar atividades subversivas. O único deles a ter efeitos jurídicos no âmbito do Ato Institucional de 9 de abril de 1964 foi o IPM da Faculdade de Medicina, com base no qual o governador demitiu sete professores de vários departamentos (Erney Camargo, Luiz Hildebrando Pereira da Silva, Thomas Maack, Luiz Rey, Pedro Henrique Saldanha, Julio Pudles, Reynaldo Chiaverini). O trabalho pretende mostrar a contribuição da doutrina da Guerra Revolucionária, adotada pelos oficiais superiores das Forças Armadas, para a instauração de IPMs e seu papel no conflito de correntes internas a essas mesmas Forças Armadas, que se manifestou com intensidade nos primeiros meses do governo Castelo Branco. Em particular, o IPM da Medicina demonstra a convergência entre o impulso geral proveniente da doutrina da Guerra Revolucionária e interesses dos que detinham o poder de administrar a Universidade de São Paulo buscando evitar mudanças. / In 1964 at least three Military Police Investigations (IPM in the Portuguese language acronym) were launched in schools of the University of São Paulo, with the stated objective of assessing and curtailing subversive activities. Only one of these had juridical effects, derived from the Institutional Act of April 9, 1964, which was the IPM on the Medical School. Based on it, the State Governor fired seven professors from several departments (Erney Camargo, Luiz Hildebrando Pereira da Silva, Thomas Maack, Luiz Rey, Pedro Henrique Saldanha, Julio Pudles, Reynaldo Chiaverini). This work aims at demonstrating the contribution of the Revolutionary War doctrine, which was at the time adopted by the Brazilian military, for the conduction of the IPM investigation, as well as its role in internal dissensions existing in the Brazilian Armed Forces which manifested itself intensely during the first months of the Castelo Branco government. Particularly, the Medical School IPM can be seen as demonstrating convergence between the momentum given by the Revolutionary War doctrine to the investigation, and the special interests of those who had the power and authority to manage the University of São Paulo with the objective of precluding change.