Made available in DSpace on 2014-06-11T19:35:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-05Bitstream added on 2014-06-13T20:26:13Z : No. of bitstreams: 1 goncalves_fs_dr_jabo.pdf: 3109118 bytes, checksum: 5a4b81536e1b9bd9d62a0e42796b675b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O fator de transcrição Oct-4 é bem conservado entre as espécies e é conhecido por ser expresso em embriões e células-tronco embrionárias (CTE), sendo um importante marcador da pluripotência. Recentemente, foi relatado que a combinação de Oct-4 com três outros fatores de transcrição Klf-4, c-Myc e Sox2 foram capazes de reprogramar células somáticas a um estado indiferenciado pluripotente, chamadas células-tronco pluripotentes induzidas (“células iPS”), as quais apresentam várias das mesmas propriedades das CTE incluindo a pluripotência, auto-renovação e proliferação. O objetivo desse estudo foi avaliar a funcionalidade do promotor Oct-4 de eqüino em CTE de murinos. Três vetores plasmidiais expressando GFP (“green fluorescent protein”) sob o controle do promotor Oct-4 de equinos, camundongo e quatro vetores lentivirais, também contendo o gene reporter GFP e os promotores Oct-4 de equinos, camundongo e humanos, pLZ2-ecOCT-EGFP (meq) (sequência equivalente de camundongos), pLZ2-ecOCT-EGFP (heq) (sequência equivalente de humanos), pLZ2-mOCT-EGFP e pLZ2-hOCT-EGFP, respectivamente, foram construídos. Todos os vetores também contêm um sítio de resistência à blasticidina que permite a seleção das células estáveis e das células transduzidas. Essas construções plasmidiais foram verificadas se funcionavam eficientemente, bem como o efeito do promotor Oct-4 em transfectar transientes e estáveis CTE. As construções com promotor Oct-4 de camundongo, humano e eqüino (sequência análoga à de camundongo) produziram somente 6% de células GFP positivas com intensidade de fluorescência (IF) >1000 pela análise em citômetro de fluxo, enquanto que o plasmídeo contendo o promotor Oct-4 de eqüino (sequência equivalente à de humanos) produziu menos células GFP positivas (>3%) com IF >1000, quando... / The pluripotency transcription factor Oct-4 is well conserved among species and is known to be expressed in embryos and embryonic stem (ES) cells; it is being an important pluripotency marker. It was recently demonstrated that the combination of Oct-4 with three other factors Klf-4, c-myc and Sox2 were able to reprogram somatic cells to a pluripotent and undifferentiated state. These cells known as induced pluripotent stem (iPS) cells share several properties with ES cells including self-renewal, proliferation and pluripotency. The aim of this study was to assess the functionality of the horse Oct-4 promoter in mouse ES cells. Three plasmids vectors expressing GFP (green fluorescent protein) under the control of the horse, mouse and four lentivirus vectors also containing reporter gene GFP and horse, mouse and human promoters, pLZ2-ecOCT-EGFP (mouse sequence equivalent), pLZ2-ecOCT-EGFP (human sequence equivalent), pLZ2-mOCT-EGFP and pLZ2-hOCT-EGFP, respectively, were built. All these vectors also contain a blasticidin resistance cassette to allow selection of transfected stable cells and transduced cells. Afterwards, to assess the functionality of the Oct-4 promoter all plasmids were tranfected the into transient and stable mouse ES cells. Constructs with mouse, human and horse (mouse analog sequence) Oct-4 promoter produced only 6% GFP positive cells with fluorescence intensity (FI)>1000 by 20 FACs assay, while plasmid horse (human analog sequence) Oct-4 promoter produced less GFP positive cells (>3%) with FI>1000, when compared with the positive control and among groups. However, GFP expression was not present in stable cells, whereas there were Blasticidin-resistant colonies-forming from 6 days post-transfection. To optimize the system in mouse ES cells, pLZ2-mOCT-EGFP and pLZ2-hOCT-EGFP lentivectors, were tested as controls. It was used HIV-1-derived... (Complete abstract click electronic access below)

Vetores lentivirais são ferramentas fundamentais para modificação celular. Sua utilização ganhou destaque devido à capacidade desses em integrar ao genoma de células que estão ou não em divisão. Grande parte dos vetores desenvolvidos são derivados do genoma do Vírus da Imunodeficiência Humana (HIV-1), portanto, modificações foram necessárias a fim de evitar a formação de Partículas Competentes em Replicação (RCLs) e garantir uma utilização segura. Com as modificações, foram produzidos os vetores lentivirais de terceira geração utilizados atualmente. Esses vetores podem ser usados para expressão constitutiva de genes, produção de proteínas recombinantes, produção de animais transgênicos e terapia gênica. Com isso, torna-se necessário o desenvolvimento de vetores lentivirais para aplicação em pesquisa básica e ensaios clínicos. Dessa forma, o presente estudo teve por objetivo a construção de vetores de expressão lentivirais aplicáveis à: 1- expressão constitutiva de genes de interesse e 2-vetores com promotores específicos para expressão de proteínas em megacariócitos. Esse trabalho descreve a construção desses vetores, sua importância e discute suas possíveis aplicações. As sequências selecionadas para produção dos vetores foram: os genes Runx1C e VkorC1 e os promotores proPF4 e proITGA2b. Todas as sequências encontram-se clonadas em vetor de clonagem e estoques de bactérias com esses vetores congeladas em glicerol foram confeccionados. Para a confecção dos vetores lentivirais, o gene Runx1C foi subclonado no vetor lentiviral base p1054-CIGWS sob controle do promotor forte CMV, enquanto o promotor proITGA2b foi subclonado no vetor base p1054-FVIII, em substituição ao promotor CMV, de forma a controlar a expressão de FVIII. Os dois vetores produzidos apresentam ainda o gene para proteína verde GFP precedida do sítio de ligação do ribossomo IRES, com expressão controlada pelo mesmo promotor interno do vetor. O trabalho possibilitou, portanto, a produção de dois vetores lentivirais bi-cistrônicos: p1054-Runx1C e pL-proITGA2b-FVIII. A construção p1054-Runx1C ainda não foi sequenciada, mas foi confirmada por restrição enzimática e apresenta potencial para aplicação em estudos de diferenciação hematopoética. Já a construção pL-proITGA2b-FVIII foi sequenciada, porém sem confirmação da região de ligação do proITGA2b ao vetor. Reações de PCR e de restrição enzimática confirmaram a ligação e sequenciamento mostrou 67% de similaridade entre a região sequenciada e o promotor ITGA2b depositado no banco de dados. Análise funcional foi realizada através da transfecção desse vetor em células HEK-293T. As células transfectadas apresentaram expressão positiva para GFP e secreção de FVIII no sobrenadante celular, evidenciando que o promotor proITGA2b clonado no vetor encontra-se ativo. Esse vetor apresenta potencial para aplicação em terapia gênica para hemofilias, pois apresenta expressão do fator de coagulação direcionado a megacariócitos e plaquetas, células que estão diretamente relacionadas ao processo de coagulação, representando grandes veículos para secreção desses fatores. Ainda, os dois vetores lentivirais gerados apresentam segurança e eficiência elevadas, pois são vetores de terceira geração auto-inativantes (SIN) e apresentam elementos regulatórios que melhoram o transporte e integração do DNA ao genoma hospedeiro. / Lentiviral vectors are fundamental tools for cell modification that gained prominence due to their ability to integrate the genome of non-dividing cells. Most of developed lentiviral vectors are derived from the genome of Human Immunodeficiency Virus (HIV-1), so modifications were necessary in order to avoid the formation of Competent Replication Particles (RCLs) and ensure safer operations. The modifications led to development of third generation lentiviral vectors currently used. These vectors can be used for constitutive gene expression, production of recombinant protein, production of transgenic animals and gene therapy. It\'s evident the need to develop lentiviral vectors for application in basic research and clinical trials. Thus this study aimed to construct lentiviral expression vectors applicable to: 1- constitutive expression of genes of interest and 2-vectors with specific promoters for expression of proteins in megakaryocytes and platelets. This paper describes the construction of these vectors, their importance and discuss their possible applications. Sequences were selected for production of the vectors: genes Runx1C and VkorC1 and proPF4 and proITGA2b promoters. All four sequences are cloned into cloning vectors and stocks of bacteria with these vectors frozen in glycerol were prepared. Lentiviral vectors were engineered from subcloning the sequence Runx1C into the basic lentiviral vector p1054- CIGWS under control of the strong CMV promoter, and from subcloning proITGA2b promoter into p1054-FVIII basic vector, replacing the CMV promoter in order to control the expression of FVIII. Both vectors exhibit the green fluorescence protein GFP gene preceded by a ribosome binding site IRES under control of vector\'s internal promoter. Therefore, this work resulted in the production of two bi-cistronic lentiviral vectors: p1054-Runx1C and pLproITGA2b-FVIII. The p1054-Runx1C construction has not yet been sequenced, but it was confirmed by digestion and has potential for use in hematopoietic differentiation studies. Though, pL-proITGA2b-FVIII construct was sequenced, but the technique didn\'t allow to confirm the binding region between proITGA2b and the vector. Although PCR reaction and digestion confirmed the construction. Sequence analysis showed 67% similarity between the sequenced region and ITGA2b promoter deposited in the database. Functional analysis was performed by transfection of this vector in HEK-293T cells. The transfected cells showed positive expression of GFP and FVIII secretion in cell supernatant, indicating that the proITGA2b promoter cloned into the vector is active. This vector has potential usage in gene therapy for hemophilia, since it can be used to express coagulation factors in megakaryocytes and platelets and these cells are directly related to the clotting process, representing great vehicles for secretion of these factors. Even more, the two lentiviral vectors generated have higher safety and efficiency, as they are self-inactivating (SIN) third-generation vectors and have regulatory elements that enhance transport and integration of DNA into the host genome.

A chaque instant notre organisme est confronté à des agents pathogènes de nature très variable. Pourtant, malgré toutes les agressions rencontrées, il maintient une certaine intégrité. Cette dernière résulte de la mise en place d’un système de défense perfectionné, fruit de la collaboration étroite de diverses cellules :le système immunitaire. Parmi toutes les cellules qui le composent, les cellules dendritiques jouent un rôle prépondérant. Disséminées dans la plupart de nos organes et tissus, elles surveillent, en alerte du moindre danger. Elles orchestrent la réponse immune :elles sont capables d'initier et polariser une réponse immune ou d'instaurer la tolérance. De nombreux traitements thérapeutiques tentent d’exploiter leurs capacités intrinsèques. Ces cellules présentent en effet un grand potentiel dans la vaccination anti-tumorale et antivirale, dans l’acceptation de greffes et le contrôle de maladies auto-immunes. Toutefois, de nombreux éclaircissements restent encore à apporter que ce soit sur l’ontogénie des cellules dendritiques, leur rôle ou leur propre biologie. <p><p>Aussi, le dessein de ce travail était d’approfondir nos connaissances fondamentales sur les propriétés moléculaires et la biologie des cellules dendritiques afin de mieux appréhender la nature et l’amplitude des réponses qu’elles induisent. A cette fin, nous avons identifié deux nouveaux gènes qu’elles expriment préférentiellement et nous avons essayé de caractériser leur fonction. L’avènement de l’utilisation de la technique d’ARN interférence dans les systèmes de mammifères et le développement des vecteurs lentiviraux nous sont apparus comme des outils présentant un réel potentiel pour répondre à nos questions. Nous avons donc généré des souris qui sur- ou sous- expriment le gène d’intérêt, par infection lentivirale d’embryons, pour tenter de cerner son rôle in vivo. Cette méthode de transgénèse était très prometteuse car rapide, efficace, peu onéreuse et sollicitait peu de compétences pour la manipulation des embryons. Cependant, l’approche s’est révélée plus laborieuse que prévu. Nous avons en effet rencontré de nombreux phénomènes de variégation et de « silencing » qui a rendu plus ardue l’utilisation des souris transgéniques. Néanmoins, nous pensons aujourd’hui être à même d’élaborer une stratégie de sélection des souris générées par transgénèse lentivirale qui ne développeraient probablement pas les problèmes rencontrés. Au cours de l’étude, nous avons également observé une fluctuation de l’activité du promoteur CAG pendant le développement thymique, pointant l’importance du choix d’un promoteur optimal en fonction du projet de recherche. Enfin, l’analyse des souris, bien que préliminaire, suggère un rôle potentiel d’un des gènes examinés dans la différenciation, la mobilisation ou la survie des cellules dendritiques, des macrophages et des lymphocytes B.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Vetores lentivirais são ferramentas fundamentais para modificação celular. Sua utilização ganhou destaque devido à capacidade desses em integrar ao genoma de células que estão ou não em divisão. Grande parte dos vetores desenvolvidos são derivados do genoma do Vírus da Imunodeficiência Humana (HIV-1), portanto, modificações foram necessárias a fim de evitar a formação de Partículas Competentes em Replicação (RCLs) e garantir uma utilização segura. Com as modificações, foram produzidos os vetores lentivirais de terceira geração utilizados atualmente. Esses vetores podem ser usados para expressão constitutiva de genes, produção de proteínas recombinantes, produção de animais transgênicos e terapia gênica. Com isso, torna-se necessário o desenvolvimento de vetores lentivirais para aplicação em pesquisa básica e ensaios clínicos. Dessa forma, o presente estudo teve por objetivo a construção de vetores de expressão lentivirais aplicáveis à: 1- expressão constitutiva de genes de interesse e 2-vetores com promotores específicos para expressão de proteínas em megacariócitos. Esse trabalho descreve a construção desses vetores, sua importância e discute suas possíveis aplicações. As sequências selecionadas para produção dos vetores foram: os genes Runx1C e VkorC1 e os promotores proPF4 e proITGA2b. Todas as sequências encontram-se clonadas em vetor de clonagem e estoques de bactérias com esses vetores congeladas em glicerol foram confeccionados. Para a confecção dos vetores lentivirais, o gene Runx1C foi subclonado no vetor lentiviral base p1054-CIGWS sob controle do promotor forte CMV, enquanto o promotor proITGA2b foi subclonado no vetor base p1054-FVIII, em substituição ao promotor CMV, de forma a controlar a expressão de FVIII. Os dois vetores produzidos apresentam ainda o gene para proteína verde GFP precedida do sítio de ligação do ribossomo IRES, com expressão controlada pelo mesmo promotor interno do vetor. O trabalho possibilitou, portanto, a produção de dois vetores lentivirais bi-cistrônicos: p1054-Runx1C e pL-proITGA2b-FVIII. A construção p1054-Runx1C ainda não foi sequenciada, mas foi confirmada por restrição enzimática e apresenta potencial para aplicação em estudos de diferenciação hematopoética. Já a construção pL-proITGA2b-FVIII foi sequenciada, porém sem confirmação da região de ligação do proITGA2b ao vetor. Reações de PCR e de restrição enzimática confirmaram a ligação e sequenciamento mostrou 67% de similaridade entre a região sequenciada e o promotor ITGA2b depositado no banco de dados. Análise funcional foi realizada através da transfecção desse vetor em células HEK-293T. As células transfectadas apresentaram expressão positiva para GFP e secreção de FVIII no sobrenadante celular, evidenciando que o promotor proITGA2b clonado no vetor encontra-se ativo. Esse vetor apresenta potencial para aplicação em terapia gênica para hemofilias, pois apresenta expressão do fator de coagulação direcionado a megacariócitos e plaquetas, células que estão diretamente relacionadas ao processo de coagulação, representando grandes veículos para secreção desses fatores. Ainda, os dois vetores lentivirais gerados apresentam segurança e eficiência elevadas, pois são vetores de terceira geração auto-inativantes (SIN) e apresentam elementos regulatórios que melhoram o transporte e integração do DNA ao genoma hospedeiro. / Lentiviral vectors are fundamental tools for cell modification that gained prominence due to their ability to integrate the genome of non-dividing cells. Most of developed lentiviral vectors are derived from the genome of Human Immunodeficiency Virus (HIV-1), so modifications were necessary in order to avoid the formation of Competent Replication Particles (RCLs) and ensure safer operations. The modifications led to development of third generation lentiviral vectors currently used. These vectors can be used for constitutive gene expression, production of recombinant protein, production of transgenic animals and gene therapy. It\'s evident the need to develop lentiviral vectors for application in basic research and clinical trials. Thus this study aimed to construct lentiviral expression vectors applicable to: 1- constitutive expression of genes of interest and 2-vectors with specific promoters for expression of proteins in megakaryocytes and platelets. This paper describes the construction of these vectors, their importance and discuss their possible applications. Sequences were selected for production of the vectors: genes Runx1C and VkorC1 and proPF4 and proITGA2b promoters. All four sequences are cloned into cloning vectors and stocks of bacteria with these vectors frozen in glycerol were prepared. Lentiviral vectors were engineered from subcloning the sequence Runx1C into the basic lentiviral vector p1054- CIGWS under control of the strong CMV promoter, and from subcloning proITGA2b promoter into p1054-FVIII basic vector, replacing the CMV promoter in order to control the expression of FVIII. Both vectors exhibit the green fluorescence protein GFP gene preceded by a ribosome binding site IRES under control of vector\'s internal promoter. Therefore, this work resulted in the production of two bi-cistronic lentiviral vectors: p1054-Runx1C and pLproITGA2b-FVIII. The p1054-Runx1C construction has not yet been sequenced, but it was confirmed by digestion and has potential for use in hematopoietic differentiation studies. Though, pL-proITGA2b-FVIII construct was sequenced, but the technique didn\'t allow to confirm the binding region between proITGA2b and the vector. Although PCR reaction and digestion confirmed the construction. Sequence analysis showed 67% similarity between the sequenced region and ITGA2b promoter deposited in the database. Functional analysis was performed by transfection of this vector in HEK-293T cells. The transfected cells showed positive expression of GFP and FVIII secretion in cell supernatant, indicating that the proITGA2b promoter cloned into the vector is active. This vector has potential usage in gene therapy for hemophilia, since it can be used to express coagulation factors in megakaryocytes and platelets and these cells are directly related to the clotting process, representing great vehicles for secretion of these factors. Even more, the two lentiviral vectors generated have higher safety and efficiency, as they are self-inactivating (SIN) third-generation vectors and have regulatory elements that enhance transport and integration of DNA into the host genome.

A pesar de la abundancia de estudios realizados sobre el papel de las células acinares en las patologías exocrinas del páncreas (i.e. pancreatitis y cáncer), el estudio de las modificaciones producidas durante la diferenciación acinar en dichas patologías, se ha visto limitado por la escasez de modelos celulares no tumorales. Resultados previos de nuestro laboratorio, muestran que las células mES (células madre embrionarias de ratón )- pluripotentes y con la capacidad para generar tipos celulares especializados- pueden desarrollar un fenotipo acinar in vitro. Los objetivos de esta tesis han sido aumentar el contenido de enzimas digestivos así como las propiedades funcionales de las células generadas. Para ello se sobreexpresaron de forma estable p48, RBPJL y Mist1en células madre por transducción lentiviral de estos genes. Obtuvimos, gracias a una estrategia de infección en múltiples etapas, líneas celulares transgénicas mES que expresaban de forma constitutiva RBPJL y/o Mist1. La superimposición de la expresión de p48 por infección lentiviral en células en proceso de diferenciación dio lugar a una fuerte expresión de enzimas digestivos, con un patrón de regulación similar al que acontece in vivo durante el desarrollo pancreático. En esta inducción, tanto p48 como RPBJL son indispensables. Por otro lado, hemos mostrado un aumento elevado en la producción de varios componentes de la maquinaria secretota dependiente de Mist1. Además, hay que hacer notar ,que las células p48/RBPJL/Mist1 exhiben una regulada-secreción en respuesta a los secretagogos acinares y una mejor actividad de que la línea celular acinar 266-6. La expresión combinada de genes clave implicados en el desarrollo pancreático en células ES es un prometedor abordaje que nos llevará a una comprensión de los sutiles procesos del desarrollo exocrino pancreático. / Despite known involvement of acinar cells in pancreatic exocrine pathologies (i.e pancreatitis and pancreatic cancer), the lack of normal cell-based models has limited the study of the alterations that occur in the acinar differentiation program. Our previous data showed that mES (murine embryonic stem) cells, which are pluripotent and have the ability to generate specialized cell types, can acquire an acinar phenotype in vitro. The aim of this work was to increase the digestive enzyme content of the generated cells as well as their functional properties based on stable overexpression of p48, RBPJL and Mist1 by lentiviral gene transduction. Thus, we engineered transgenic mES cell lines constitutively expressing RBPJL and/or Mist1 using a multi-step infection strategy. The superimposition of p48 expression by lentiviral infection of differentiating cells resulted in a strong expression of digestive enzymes, with a pattern of regulation similar to what occurs in vivo during pancreatic development. In this induction, both p48 and RPBJL are indispensable. On the other hand, we showed a high increase in the production of several components of the secretory machinery which was dependent of Mist1. Importantly, p48/RBPJL/Mist1 cells exhibited a regulated-secretory in response to acinar secretagogues and a better secretion activity than the 266-6 acinar cell line. Combined expression of key genes involved in pancreatic development in ES cells may be a promising approach to better understand subtle steps of pancreatic exocrine development.

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La transplantation d'hépatocytes est un procédé séduisant pour remplacer les cellules déficientes dans un foie anatomiquement normal. Dans les maladies métaboliques héréditaires hépatiques (MMHH), la thérapie cellulaire présente un potentiel espoir thérapeutique. Le remplacement d'un pourcentage restreint (5-10%) d'hépatocytes déficients par des hépatocytes normaux pourrait rétablir durablement la fonction métabolique. Les résultats des essais cliniques de transplantation d'hépatocytes génétiquement modifiés ou non sont moins concluants, montrent une prise de greffe insuffisante et, dans la plupart des études, un effet thérapeutique transitoire. L'efficacité limitée de la transplantation d'hépatocytes isolés dans le traitement des MMHH semble en partie liée au faible pourcentage de la masse hépatocytaire reconstituée par les hépatocytes définitivement greffés et fonctionnels. De nombreux modèles animaux ont été développés pour étudier les facteurs pouvant augmenter le nombre et le pourcentage d'hépatocytes transplantés et greffés. Cependant, la majorité de ces modèles ne sont pas transposables en clinique car ils présentent des risques importants ou mal évalués pour les patients. Les principaux objectifs de ce travail ont été d'étudier des moyens peu invasifs pour induire une régénération hépatique et une prise de greffe hépatocytaire significatives dans le but de développer une nouvelle approche de transplantation d'hépatocytes génétiquement modifiés ex vivo pour le traitement de l'hypercholestérolémie familiale. L'effet d'une embolisation portale partielle (EPP) réversible sur la prolifération hépatocytaire et la régénération hépatique a été évalué chez le macaque. A la différence de l'EPP par un produit non résorbable, il ne s'agit pas d'une approche potentiellement délétère à long terme. Une obstruction veineuse plus complète a été provoquée en utilisant le Curaspon®, une gélatine biodégradable, en forme de poudre. Nous avons démontré pour la première fois dans la littérature l'efficacité d'une EPP réversible à induire une importante prolifération hépatocytaire et régénération hépatique. Nos données suggèrent qu'une occlusion portale initiale et temporaire est suffisante pour déclencher les mécanismes responsables d'une régénération hépatique dans le foie non-embolisé. L'utilisation du Curaspon® en poudre peut être considérée comme la forme la plus évoluée d'EPP : très distale, résorbable, qui dure suffisamment pour induire l'hypertrophie hépatique. Cette technique pourrait être indiquée dans des situations cliniques nécessitant une régénération hépatique de courte durée (ex. le traitement des cancers du foie en plusieurs étapes) ou dans des cas qui ne nécessitent pas une résection hépatique, comme la transplantation d'hépatocytes pour le traitement de MMHH. Ces résultats nous ont permis d'évaluer cette approche dans notre protocole préclinique de thérapie génique pour le traitement de l'hypercholestérolémie familiale chez le primate, par autotransplantation d'hépatocytes génétiquement modifiés ex vivo par un vecteur lentiviral. Nous avons démontré que l'EPP réversible induit une régénération hépatique du foie non-embolisé et améliore notablement les résultats de la transplantation d'hépatocytes isolés génétiquement modifiés exprimant la GFP. Seize semaines après la transplantation, les hépatocytes transduits et greffés exprimaient le transgène contrôlé par le promoteur apo-AII humain. Notre protocole a montré pour la première fois chez un gros animal que l'EPP par un produit résorbable entraine avec des conditions de sécurité optimales une repopulation hépatique importante par des hépatocytes transduits par un vecteur lentiviral, et ceci même à distance de la transplantation hépatocytaire. Les résultats encourageants de ces travaux nous ont ouvert la voie pour avancer sur notre projet préclinique et envisager la réalisation d'une étude clinique de phase I/II pour le traitement de l'hypercholestérolémie familiale.

Après 30 années de recherche, de nombreux obstacles s'opposent encore à la conception d'un vaccin contre le SIDA. En effet, il n'existe pas de consensus sur les corrélats immunitaires de protection qu'il devra induire ni sur les mécanismes à l'origine de la progression vers le SIDA chez les individus infectés. Dans un premier temps, nous avons cherché à concevoir un virus hybride structuralement semblable au VIH-1 et capable de se répliquer exclusivement dans le cytoplasme des cellules infectées. Dans cet objectif, nous avons développé des nouveaux vecteurs bi et tri-cistroniques dérivés du poliovirus et contenant les séquences des gènes gag et/ou env du VIH-1. Nous avons montré que ces réplicons permettaient l'expression des protéines structurales du VIH-1 sous leur forme mature. Dans un second temps, nous avons mis en évidence une corrélation indiquant que, plus la composition nucléotidique (% A/T/G/C) d'un lentivirus diverge de celle de son hôte, plus la probabilité qu'il soit pathogène est élevée. Nous avons montré que l'optimisation artificielle de la composition nucléotidique de séquences d'ARN lentivirales diminuait leur capacité d'induction d'interféron (IFN-I) après transfection. Nous avons ensuite synthétisé un virus de l'immunodéficience simienne (VIS) dont la séquence a été artificiellement optimisée à la composition nucléotidique moyenne du macaque. Ce virus présente une capacité d'induction d'IFN-I in vitro réduite par rapport au VIS sauvage. Ces données indiquent pour la première fois un lien entre la composition nucléotidique du génome des lentivirus et la progression vers le SIDA. Elles suggèrent de nouvelles stratégies vaccinales d'atténuation du VIH-1. / After over thirty years of AIDS epidemic, we still need to identify immunological correlates of protection against AIDS and we do not properly understand how HIV causes AIDS in infected individuals. In order to reproduce the protective capacity of live attenuated viruses, we first aimed at generating a hybrid virus structurally similar to HIV-1 and able to replicate exclusively in the cytoplasm of infected cells. We developed new polioviral pluricistronic vectors that contain HIV-1 packaging sequences, gag gene and/or env gene. We then showed that the use of these replicons was compatible with the production of processed and mature HIV structural proteins. Secondly, we investigated the consequences of the lentivirus nucleotide composition (% A/T/G/C) bias on their pathogenicity. We found a correlation, indicating that AIDS results from infection by primate lentiviruses having the most divergent nucleotide composition compared to their hosts, whereas less divergent lentiviruses cause non-pathogenic infections. A strong type I interferon (IFN-I) response during the chronic phase of infection is a typical feature of lentiviral pathogenic infection. We showed that nucleotide optimization of lentiviral RNA sequences dramatically reduce their in vitro capacity to induce IFN-I. We synthesized a simian immunodeficiency virus (SIV), whose genome sequence was artificially optimized to the macaque average nucleotide composition. This virus showed a reduced capacity to stimulate IFN-I in vitro than wt SIV. These data indicate for the first time a link between the nucleotide composition of lentiviruses and their pathogenicity. They suggest new vaccine attenuation strategies against AIDS.

Dans la cellule, les ARN pré messagers contenant des introns sont normalement retenus au noyau par leur interaction avec des facteurs d’épissage. Cependant, les ARN partiellement et non épissés des rétrovirus doivent entrer dans le cytoplasme pour servir de matrice pour la synthèse de certaines protéines telles que Env, Gag et Gag-Pol ainsi que d’ARN génomique qui sera empaqueté dans les nouveaux virions. Un mécanisme post-transcriptionnel utilisé par les lentivirus pour éviter la séquestration nucléaire de ces ARNm dépend d’une protéine virale appelée Rev. Pour assurer sa fonction d’exportation, Rev doit transiter entre le noyau et le cytoplasme et doit aussi pouvoir former des multimères. Par conséquent, Rev est dotée de domaines fonctionnels lui procurant ces habiletés. On retrouve le domaine riche en arginines qui contient le domaine de liaison à l’ARN et le signal de localisation nucléaire (NLS), un second domaine, riche en leucines, porte le signal d’exportation nucléaire (NES) et finalement le domaine de multimérisation. Bien que les protéines Rev du virus de l’immunodéficience humaine de type 1 (VIH-1) et bovine (VIB) aient été caractérisées, aucune étude n’a été réalisée pour la protéine Rev du virus de la maladie de Jembrana (JDV) et très peu sur le virus de l’immunodéficience féline (VIF). Comme les domaines fonctionnels et la voie d’importation des protéines Rev déjà caractérisées sont différents, nous supposons que chaque protéine Rev possède une organisation qui lui est propre et que les mécanismes de transport nucléo-cytoplasmique diffèrent entre les virus. Ce projet a pour objectif de caractériser ces domaines pour la protéine Rev du JDV et ceux du VIF ainsi que les mécanismes permettant leur transport nucléaire. L’utilisation de mutants de la protéine Rev de ces virus couplés à la protéine de fluorescente verte (EGFP) exprimés dans des cellules appropriées et observés par microscopie a permis d’identifier des séquences NLS et NES différentes de celles déjà caractérisées. Le NLS de la protéine Rev du JDV a été identifié et est composé des résidus arginines de la séquence 76-RRPARRPPIRR-87 avec un NoLS composé des mêmes résidus en plus des arginines R74, R103 et R104. Son NES est composé des résidus hydrophobes de la séquence 116-MAELEERFEDLAL-128 et est du type de l’inhibiteur de la protéine kinase (PKI pour « protéine kinase inhibitor »). Pour la protéine Rev du VIF, son NLS est composé des résidus basiques de la séquence 84-KKKRQRRRRKKKAFKK-99. Le NoLS est composé des mêmes acides aminés en plus du résidu K82. De plus, les essais d’importation nucléaires et d’interaction semblent indiquer que les voies d’importation utilisées diffèrent entre les virus et que plusieurs voies peuvent être utilisées. Ces travaux pourront éventuellement servir de base pour identifier de nouvelles cibles thérapeutiques contre les lentivirus. / In the cell, pre-messenger RNAs containing introns are normally retained in the nucleus by their interaction with splicing factors. However, the partially and unspliced ​​RNAs of retroviruses must enter the cytoplasm to serve as a template for the synthesis of certain proteins such as Env, Gag and Gag-Pol as well as genomic RNA to be packaged in the new virions. A post-transcriptional mechanism used by lentiviruses to prevent nuclear sequestration of these mRNAs depends on a trans-activator, the viral protein Rev. To ensure its export function, Rev must be able to shuttle between the nucleus and the cytoplasm and to form multimers. As a result, Rev has functional domains that provide these abilities: the arginine-rich domain, which contains the RNA binding domain and the nuclear localization signal (NLS), a second domain, rich in leucine, corresponding to the nuclear export signal (NES) and finally the multimerization domain. Although the Rev proteins of the human and bovine immunodeficiency virus (HIV-1 and BIV respectively) have been characterized, no studies have been performed for the Jembrana disease virus (JDV) Rev protein and very little on the feline immunodeficiency virus (FIV). Since the functional domains and import pathway of the already characterized Rev proteins are different, we assume that each Rev protein has its own organization and that the nucleo-cytoplasmic transport mechanisms differ between viruses. The goal of this project is to characterize these domains for the JDV and FIV Rev proteins as well as to elucidate mechanisms for their nuclear transport. The use of Rev mutants fused to the EGFP expressed in appropriate cells and observed by microscopy has identified NLS and NES sequences that differ from those already characterized. JDV Rev NLS is composed of arginine residues in the 76-RRPARRPPIRR-87 sequence with a NoLS composed of the same residues with the addition of arginine R74, R103 and R104. JDV Rev NES is composed of hydrophobic residues in the 116-MAELEERFEDLAL-128 sequence and is of the protein kinase inhibitor type (PKI). For the FIV Rev protein, its NLS is composed of basic residues in the 84-KKKRQRRRRKKKAFKK-99 sequence. FIV Rev NoLS is composed of the same residues with the addition of the lysine at position 82. In addition, the nuclear import and interaction tests suggest that the import routes used by Rev differ between the different viruses studied and that more than one import pathway may be used. This work could serve as a basis for identifying new therapeutic targets against lentiviruses.

Indiana University-Purdue University Indianapolis (IUPUI) / Immunotherapy for cancer has held much promise as a potent modality of cancer treatment. The ability to selectively destroy diseased cells and leave healthy cells unharmed has been the goal of cancer immunotherapy for the past thirty years. However, the full capabilities of cancer immunotherapies have been elusive. Cancer immunotherapies have been consistently hampered by limited immune reactivity, a diminishing immune response over time, and a failure to overcome self-tolerance. Many of these deficiencies have been borne-out by immunotherapies that have focused on the adoptive transfer of activated or genetically modified mature CD8+ T cells. The limitations inherent in therapies involving terminally differentiated mature lymphocytes include limited duration, lack of involvement of other components of the immune system, and limited clinical efficacy. We sought to overcome these limitations by altering and enhancing long-term host immunity by genetically modifying then transplanting HSCs. To study these questions and test the efficiency of gene transfer, we cloned a tumor reactive HLA-DR4-restricted CD4+ TCR specific for the melanocyte differentiation antigen TRP-1, then constructed both a high expression lentiviral delivery system and a TCR Tg expressing the same TCR genes. We demonstrate with both mouse and human HSCs durable, high-efficiency TCR gene transfer, following long-term transplantation. We demonstrate the induction of spontaneous autoimmune vitiligo and a TCR-specific TH1 polarized memory effector CD4+ T cell population. Most importantly, we demonstrate the destruction of subcutaneous melanoma without the aid of vaccination, immune modulation, or cytokine administration. Overall, these results demonstrate the creation of a novel translational model of durable lentiviral gene transfer, the induction of spontaneous CD4+ T cell immunity, the breaking of self-tolerance, and the induction of anti-tumor immunity.