Le nombre d’auteurs contemporains qui écrit pour les adultes et pour les enfants va croissant, à tel point que la critique anglophone a forgé le terme de crosswriters pour les désigner. Ce travail se propose d’observer ces va-et-vient entre L’école des loisirs et les Éditions de l’Olivier de 1991 à 2011. Ces circulations répondent à d’importants enjeux éditoriaux et témoignent du rôle crucial des éditeurs dans l’accompagnement des écrivains. Cette thèse s’intéresse plus particulièrement à Christophe Honoré et Manuela Draeger (un des hétéronymes d’Antoine Volodine). Tous deux usent singulièrement du crosswriting puisque certains de leurs textes pour enfants et de leurs textes pour adultes se répondent au point qu’un inter-dit peut siéger dans le blanc qui sépare ces deux corpus. Ce phénomène d’intratextualité, adossé à un geste de polyadresse, remet en cause l’intransitivité supposée de la littérature car pour être décrypté, ce dit en suspens appelle un lecteur transgénérationnel. Cet inter-dit est le lieu où se jouent des transitions d’un âge vers un autre, des transmissions d’une génération à une autre... Mais c’est aussi le lieu de ce qui ne passe pas et vient trouer l’œuvre pour faire écho au trauma individuel ou collectif. Et si c’est toujours le texte pour adultes qui délègue au texte pour enfants ce qui ne peut être articulé dans une langue adultocentrée, ces transferts ne viennent jamais suturer la béance du dispositif intratextuel mais explorent en littérature jeunesse d’autres rapports à la langue et disent quelque chose de l’être de langage que nous sommes. / The number of contemporary authors who write both for adults and children keeps rising, so much so that anglophone criticism has coined the term crosswriters to label the phenomenon. This work proposes to observe back-and-forth crossings between L’école des loisirs and Éditions de l’Olivier between 1991 and 2011. What motivate these crossings are important editorial stakes that attest to the crucial role played by publishers in guiding their authors. This dissertation will look more specifically to Christophe Honoré and Manuela Draeger (one of Antoine Volodine’s heteronyms). Both writers resort to crosswriting in singular ways as some of their children’s books and books for adults respond to one another to such an extent that what I call an “inter-diction” lodges itself in the interstice that divides their respective corpuses. This phenomenon of intratextuality, supported by a gesture of polyaddress, calls into question literature’s supposed intransitivity given that, in order to be decrypted, this suspended diction calls for a transgenerational reader. This inter-diction is the stage where are performed transitions from one age to another and where occur transmissions from one generation to the next. But it is also the site of what does not pass, of what punctures the work in an echo to individual or collective trauma. And if it is always the texts written for an adult readership that devolve to those for children what cannot be articulated in an adultocentered language, these transfers never seek to suture the abyss opened by intratextuality but rather explore through children’s literature alternative relations to language, thereby teaching us something about the linguistic beings that we are.

O poli(ácido láctico) (PLA) é um polímero biodegradável, biocompatível e bioabsorvível proveniente de fontes renováveis. Constitui uma excelente alternativa sustentável para substituição dos polímeros provenientes de petróleo, atualmente dominantes no mercado industrial. Apesar das vantagens, o PLA tem baixa tenacidade e reduzida elongação na ruptura a temperatura ambiente, o que torna a sua utilização limitada em usos que necessitem de alta deformação plástica em níveis de exigência mecânicos elevados. Misturas mecânicas de PLA com polímeros altamente flexíveis, como é o caso da poli(ε-caprolactona) (PCL), podem resultar em novos materiais com propriedades mecânicas adequadas para diferentes aplicações. Blendas PLA/PCL são completamente imiscíveis, sendo seu comportamento mecânico altamente dependente da interação interfacial entre os componentes da blenda. Portanto, o objetivo desse trabalho é avaliar o efeito compatibilizante de um copolímero em bloco de baixa massa molar (2000 g mol-1) derivado de ε-caprolactona e policarbonato (C2) e, disponível comercialmente em blendas imiscíveis PLA/PCL. Blendas binárias e ternárias foram preparadas por mistura mecânica no estado fundido via processo de extrusão em rosca simples. O teor de PLA nas blendas foi de 75, 50 e 25% (em massa) e a concentração do copolímero de 0, 1, 3, 5 e 7% (em massa). O comportamento térmico, morfológico e mecânico das blendas compatibilizadas e não compatibilizadas foi avaliado por Calorimetria Exploratória Diferencial (DSC), Análise Termodinâmico-Mecânica (DMTA), Microscopia Eletrônica de Varredura (MEV) e ensaios de tração, flexão e impacto Izod. Os resultados de DSC e DMTA indicaram que o copolímero provocou pequena redução na temperatura de transição vítrea (Tg) do PLA, sugerindo que o C2 é solúvel no PLA. Entretanto, nas micrografias das superfícies de fraturas do PLA foi nítida a presença de pequenas micelas formadas pelo copolímero em bloco, indicando que há um limite de solubilidade do compatibilizante na fase de PLA. Os resultados obtidos em tração mostraram que com o aumento do teor de compatibilizante, a tensão no escoamento, a tensão na ruptura e o módulo elástico das blendas sofrem alterações. A propriedade de tenacidade, avaliada no ensaio de impacto Izod, mostrou que as blendas tiveram um ganho na resistência quando comparadas com o PLA puro. Os resultados mostraram que o copolímero em bloco derivado de ε-caprolactona e policarbonato alifático pode atuar como compatibilizante para blendas PLA/PCL / Poly(lactic acid) (PLA) is a biodegradable, biocompatible and bioabsorbable polymer from renewable sources. It is an excellent sustainable alternative for replacing petroleum polymers, currently dominant in the industrial market. Despite the advantages, PLA has low toughness and reduced elongation at room temperature, which makes its use limited in uses that require high plastic deformation under high mechanical stress levels. Mechanical mixtures of PLA with highly flexible polymers, such as poly(ε-caprolactone) (PCL), may result in new materials with mechanical properties suitable for different applications. PLA/PCL blends are completely immiscible, and their mechanical behavior is highly dependent on the interfacial interaction between the components of the blend. Therefore, the objective of this work is to evaluate the compatibilizing effect of a low molar mass block copolymer (2000 g mol-1) derived from ε-caprolactone and polycarbonate (C2) and commercially available in PLA/PCL immiscible blends. Binary and ternary blends were prepared by mechanical mixing in the melted state via single-screw extrusion process. The content of PLA in the blends was 75, 50 and 25% (% by mass) and the copolymer concentration was 0, 1, 3, 5 and 7% (% by mass). The thermal, mechanical and morphological behavior of compatibilized and non-compatibilized blends was evaluated by differential scanning calorimetry (DSC), thermodynamic-mechanical analysis (DMTA), scanning electron microscopy (SEM), tensile test, flexion test, and Izod impact. The results of DSC and DMTA indicated that the copolymer caused a small reduction in the glass transition temperature (Tg) of PLA, suggesting that C2 is soluble in PLA. However, in the micrographies of the fracture surfaces of the PLA the presence of small micelles formed by the block copolymer is clear, indicating that there is a limit of solubility of the compatibilizer in the PLA phase. The results obtained in a tensile test showed that with the increase of the compatibilizing content, the tension in the flow, the tension at rupture and the elastic modulus of the blends undergo changes. The tenacity property, evaluated in the Izod impact test, showed that the blends had a gain in resistance when compared to pure PLA. The results showed that block copolymer derived from ε-caprolactone and aliphatic polycarbonate can act as a compatibilizer for PLA/PCL blends.

Este trabalho apresenta um estudo sobre a síntese e propriedades do copolímero poli(l,l-lactídeo-stat-e-caprolactona)-bloco-poli(óxido de etileno)-bloco-poli(l,l-lactideostat-e-caprolactona). Poli(óxido de etileno) de massa molar 20.000 u.m.a. e poli(óxido de etileno) modificado, preparado a partir de poli(glicol etilênico) de massa molar 4.000 u.m.a., foram selecionados para o processo da síntese. A reação foi feita pela polimerização por abertura de anel em massa a 120ºC usando octoanato de estanho como iniciador. A composição química de cada amostra foi determinada com auxílio de RMN-1H e RMN-13C e suas propriedades mecânicas foram verificadas e comparadas utilizando análises térmicas como DMTA, DSC, TG e a aplicação da MEV como análise complementar. A observação pelas fotos de MOLP permitiu a visualização do comportamento de nucleação dos copolímeros e as características de sua cristalinidade. Seu grau de cristalinidade e as fases cristalinas foram identificados por difração de raios X (WAXS). A biocompatibilidade do material também foi examinada pela cultura de células. Os resultados de caracterização indicam o sucesso da copolimerização, as propriedades elastoméricas e, sua não citotoxidade comprovaram a possibilidade do uso destes copolímeros como biomateriais. Contudo, o tempo prolongado de reação e baixa incorporação do monômero lactídeo ainda são questões a serem melhoradas para a viabilização do copolímero como material de implante na área biomédica. / This work includes the study of the synthesis and characterization of the copolymer poly(l,l-lactide-stat-e-caprolactone)-b-PEG-b-poly(l,l-lactide-stat-e-caprolactone). Poly (ethylene oxide) with molar weight 20.000 and poly(ethylene oxide) modified, prepared from poly(ethylene oxide) with molar weight 4000 have been selected for this synthesis process. The reaction was done by ring-opening bulk polymerization, using stannous octoate as initiator at 120ºC. The chemical composition of samples were determined by 1H-NMR and 13C-NMR and their mechanical properties were verified using thermal analyses like DMTA, DSC and TG. Scanning electron microscopy (SEM) was applied as a complementary analysis. The pictures of polarizing optical microscopy showed us the copolymer\'s nucleation behaviors and their respective crystallization. The degrees of crystallinity and phase of copolymers were determined by WAXS. The biocompatibility of the copolymer was examined by cell cultivation test. The result of these analyses above indicated the success of synthesis. Their rubbery properties and non-toxicity allowed their application as biomaterial. However, the long reaction time and low incorporation of monomer of lactide might to be improved to increase its potential use in biomedical area in the future.

Le traumatisme crânien (TC) représente un des problèmes majeurs de santé publique, pour lequel à l’heure actuelle il n’existe aucun traitement. Le TC induit une neuro-inflammation délétère qui pourrait contribuer à l’apparition des lésions de la substance blanche (SB). Ces dernières sont à l’origine de lourdes conséquences neurologiques chez les patients victimes de TC. Néanmoins, très peu d’études se sont intéressées à ces lésions bien que plus sévères que les lésions de la substance grise. Ainsi une meilleure connaissance de leur évolution et des causes devient indispensable. L’hyperactivation de la poly(ADP ribose)polymérase (PARP) joue un rôle délétère dans les conséquences post-traumatiques, notamment sur la neuro-inflammation. Ainsi son inhibition pourrait être bénéfique le développement des lésions de la SB. Dans ce contexte, l’objectif de notre travail a été d’évaluer le rôle de la PARP dans les lésions de la SB dans un modèle expérimental de TC induit par impact cortical contrôlé chez la souris. Dans une première partie, nous avons étudié l’évolution de la démyélinisation dans le corps calleux, une structure riche en SB, entre 6 heures et 3 mois post-TC. Parallèlement, les évolutions de la lésion cérébrale, des déficits sensorimoteurs, de la neuro-inflammation et de l’œdème cérébral ont été étudiées. Le TC induit (1) une démyélinisation dès 7 jours et au moins jusqu’à 3 mois post-TC, précédée par (2) une lésion cérébrale entre 24 et 72 heures suivie par une cicatrisation, (3) une neuro-inflammation entre 6 heures et 7 jours et (4) un œdème cérébral entre 6 et 72 heures post-TC. De plus, le TC induit des déficits sensorimoteurs à 6 heures et 3 mois. Ces résultats montrent que ce modèle est adapté pour étudier les lésions de la SB post-TC, et que la neuro-inflammation et l’œdème cérébral pourrait être impliqués dans la démyélinisation. Dans une deuxième partie, nous avons étudié le rôle de la PARP dans les lésions de la SB suite à TC à l’aide de souris knockout (KO) et wild-type (WT) pour le gène de la PARP. Nous avons mis en évidence que les souris KO ne présentent pas de démyélinisation bilatérale du corps calleux après un TC par rapport aux souris WT à 7 jours post-TC, démontrant pour la première fois l’implication de cette enzyme dans les lésions de la SB consécutives à un TC. De plus, nous avons constaté que les souris KO non traumatisées présentent une diminution de myélinisation comparativement aux souris WT non traumatisées, suggérant un rôle de la PARP dans le processus physiologique de la myélinisation.En conclusion, l’ensemble de ce travail expérimental a permis (1) une meilleure caractérisation de la démyélinisation post-TC et des mécanismes potentiellement impliqués dans cette dernière, et (2) de démontrer pour la première fois le rôle délétère de la PARP dans la démyélinisation induite par un TC. Nos travaux suggèrent le potentiel de l’inhibition de la PARP comme stratégie thérapeutique pour la prévention des lésions de la SB post-traumatiques. / Traumatic brain injury (TBI) is a leading cause of death and disability for which there is no neuroprotective treatment up to date. It results in neuroinflammation that may participate in lasting motor and cognitive impairments accompanied by changes in white matter (WM) tracts. WM lesions, evidenced by demyelination, are associated with neurological disorders and in clinical studies are common consequences in patients with chronic TBI. Several studies suggest a contribution of an overactivation of the poly(ADP-ribose) polymerase (PARP) to the neuroinflammatory response which may lead to demyelination. The first part of this study was dedicated to a detailed in vivo assessment of the evolution over time of neurological disorders, cerebral lesion and edema, neuroinflammation and white matter injury induced by controlled cortical impact (CCI) between 6 hours and 12 weeks post-TBI. Notably in the corpus callosum, a significant demyelination starting at 7 days appeared to be a major consequence to post-traumatic neuroinflammation associated with motor dysfunctions. The second part of this study was dedicated to the evaluation of PARP’s role in WM lesions post-TBI, using PARP knockout (KO) mice. Our main findings reveal a diminished demyelination in the corpus callosum of TBI PARP KO as opposed to TBI PARP wildtype specimens. Hence, these data suggest for the first time PARP’s deleterious role in post-traumatic demyelination. In conclusion, taken together these data give an overall view of motor/sensorimotor deficits, neuroinflammation and demyelination in a CCI model of TBI that could help to validate pharmacological strategy for preventing post-traumatic WM injury. Notably, PARP’s inhibition seems to be a valid candidate as this enzyme participates in the establishment of a demyelinating process.

O poli(ácido láctico) (PLA) é um polímero biodegradável, biocompatível e bioabsorvível proveniente de fontes renováveis. Constitui uma excelente alternativa sustentável para substituição dos polímeros provenientes de petróleo, atualmente dominantes no mercado industrial. Apesar das vantagens, o PLA tem baixa tenacidade e reduzida elongação na ruptura a temperatura ambiente, o que torna a sua utilização limitada em usos que necessitem de alta deformação plástica em níveis de exigência mecânicos elevados. Misturas mecânicas de PLA com polímeros altamente flexíveis, como é o caso da poli(ε-caprolactona) (PCL), podem resultar em novos materiais com propriedades mecânicas adequadas para diferentes aplicações. Blendas PLA/PCL são completamente imiscíveis, sendo seu comportamento mecânico altamente dependente da interação interfacial entre os componentes da blenda. Portanto, o objetivo desse trabalho é avaliar o efeito compatibilizante de um copolímero em bloco de baixa massa molar (2000 g mol-1) derivado de ε-caprolactona e policarbonato (C2) e, disponível comercialmente em blendas imiscíveis PLA/PCL. Blendas binárias e ternárias foram preparadas por mistura mecânica no estado fundido via processo de extrusão em rosca simples. O teor de PLA nas blendas foi de 75, 50 e 25% (em massa) e a concentração do copolímero de 0, 1, 3, 5 e 7% (em massa). O comportamento térmico, morfológico e mecânico das blendas compatibilizadas e não compatibilizadas foi avaliado por Calorimetria Exploratória Diferencial (DSC), Análise Termodinâmico-Mecânica (DMTA), Microscopia Eletrônica de Varredura (MEV) e ensaios de tração, flexão e impacto Izod. Os resultados de DSC e DMTA indicaram que o copolímero provocou pequena redução na temperatura de transição vítrea (Tg) do PLA, sugerindo que o C2 é solúvel no PLA. Entretanto, nas micrografias das superfícies de fraturas do PLA foi nítida a presença de pequenas micelas formadas pelo copolímero em bloco, indicando que há um limite de solubilidade do compatibilizante na fase de PLA. Os resultados obtidos em tração mostraram que com o aumento do teor de compatibilizante, a tensão no escoamento, a tensão na ruptura e o módulo elástico das blendas sofrem alterações. A propriedade de tenacidade, avaliada no ensaio de impacto Izod, mostrou que as blendas tiveram um ganho na resistência quando comparadas com o PLA puro. Os resultados mostraram que o copolímero em bloco derivado de ε-caprolactona e policarbonato alifático pode atuar como compatibilizante para blendas PLA/PCL / Poly(lactic acid) (PLA) is a biodegradable, biocompatible and bioabsorbable polymer from renewable sources. It is an excellent sustainable alternative for replacing petroleum polymers, currently dominant in the industrial market. Despite the advantages, PLA has low toughness and reduced elongation at room temperature, which makes its use limited in uses that require high plastic deformation under high mechanical stress levels. Mechanical mixtures of PLA with highly flexible polymers, such as poly(ε-caprolactone) (PCL), may result in new materials with mechanical properties suitable for different applications. PLA/PCL blends are completely immiscible, and their mechanical behavior is highly dependent on the interfacial interaction between the components of the blend. Therefore, the objective of this work is to evaluate the compatibilizing effect of a low molar mass block copolymer (2000 g mol-1) derived from ε-caprolactone and polycarbonate (C2) and commercially available in PLA/PCL immiscible blends. Binary and ternary blends were prepared by mechanical mixing in the melted state via single-screw extrusion process. The content of PLA in the blends was 75, 50 and 25% (% by mass) and the copolymer concentration was 0, 1, 3, 5 and 7% (% by mass). The thermal, mechanical and morphological behavior of compatibilized and non-compatibilized blends was evaluated by differential scanning calorimetry (DSC), thermodynamic-mechanical analysis (DMTA), scanning electron microscopy (SEM), tensile test, flexion test, and Izod impact. The results of DSC and DMTA indicated that the copolymer caused a small reduction in the glass transition temperature (Tg) of PLA, suggesting that C2 is soluble in PLA. However, in the micrographies of the fracture surfaces of the PLA the presence of small micelles formed by the block copolymer is clear, indicating that there is a limit of solubility of the compatibilizer in the PLA phase. The results obtained in a tensile test showed that with the increase of the compatibilizing content, the tension in the flow, the tension at rupture and the elastic modulus of the blends undergo changes. The tenacity property, evaluated in the Izod impact test, showed that the blends had a gain in resistance when compared to pure PLA. The results showed that block copolymer derived from ε-caprolactone and aliphatic polycarbonate can act as a compatibilizer for PLA/PCL blends.

O objetivo desse trabalho foi preparar compósitos de matriz de PCL reforçados com microfibrilas de PLA preparadas in situ a partir do controle da morfologia de blendas PLA/PCL. Embora a formação da morfologia fibrilar não tenha sido observada nas condições de extrusão empregadas, estudos do comportamento reológico de blendas de composição 50% PLA / 45% PCL / 5% de compatibilizante (% em massa) mostraram que microfibrilas de PLA podem ser obtidas entre 102 e 104 s-1. Assim, a técnica de reometria capilar foi utilizada para controlar a morfologia de blendas PLA/PCL. Compósitos de matriz de PCL reforçados com 5, 10, 20 e 30% (% em massa) de microfibrilas de PLA foram preparados em extrusora rosca simples, utilizando perfil de temperatura acima da temperatura de fusão do PCL, mas abaixo da temperatura de fusão do PLA, visando preservar a morfologia do PLA. O comportamento morfológico, térmico e mecânico dos compósitos foram avaliados por microscopia eletrônica de varredura (MEV), microscopia óptica com luz polarizada (POM), calorimetria exploratória diferencial (DSC), análise térmica dinâmico-mecânica (DMA) e ensaios mecânicos de tração e de impacto Izod. As curvas DSC mostraram um aumento no grau de cristalinidade da matriz de PCL com o aumento do teor de microfibrilas, o que provavelmente justifica os altos valores de módulo de Young determinados nos compósitos. A aplicação da Regra das Misturas comprovou que os compósitos fabricados exibiram boa orientação das microfibrilas na direção do esforço mecânico aplicado, com valores de módulos próximos ao limite superior da curva. No entanto, a adesão não uniforme entre a matriz e o reforço observada por MEV, resultou na queda da resistência à tração e resistência ao impacto dos compósitos, quando comparados ao PCL puro. A composição com 10% de microfibrilas apresentou um bom balanço de módulo de Young e resistência ao impacto, com potencial de viabilidade em uma série de aplicações biomédicas. / The aim of this work is to prepare PCL composites reinforced with PLA microfibrils prepared in situ from the morphology of PLA/PCL blends control. Although the formation of fibrillar morphology has not been observed under the extrusion conditions employed, studies of the rheological behavior of 50% PLA/ 45% PCL / 5% compatibilizer blends have shown that PLA microfibrils can be obtained between 102 and 104 s-1. Thus, the capillary rheometry technique was used to control the morphology of PLA /PCL blends. PCL composites reinforced with 5, 10, 20 and 30% (% by mass) PLA microfibrils were prepared in a single screw extruder using a temperature profile above the PCL melting temperature, but below the melt temperature of PLA, to preserve the PLA morphology. The morphology, thermal and mechanical behavior of the composites were evaluated by scanning electron microscopy (SEM), optical polarized light microscopy (POM), differential scanning calorimetry (DSC), dynamic mechanical-mechanical analysis (DMA) and mechanical tensile tests and Izod impact. DSC curves showed an increase in the degree of crystallinity of the PCL matrix with increasing the PLA microfibrils content, which probably justify the high Young\'s modulus values determined in the composites. The application of the Mix Rule proved that the composites showed good orientation of the PLA microfibrils in the direction of applied mechanical stress, presenting modules values near the upper limit of the curve. However, the non-uniform adhesion between the matrix and the reinforcement observed by MEV, caused the decrease of the tensile and impact strength when compared to pure PCL. The composition with 10% of PLA microfibrils exhibited a good balance of Young\'s modulus and impact strength, with potential viability in a number of biomedical applications.

Les glioblastomes sont des tumeurs cérébrales très agressives présentant une médiane de survie de 15 mois malgré l’usage du traitement de référence. Parmi les stratégies innovantes anti-glioblastome, les microARNs (miARN) constituent de nouvelles cibles et des outils thérapeutiques à fort potentiel. En outre, pour atteindre les cellules tumorales notamment au niveau loco-régional, les miARNs nécessitent d’être administrés grâce à des vecteurs sûrs et efficaces. L’objectif de ce travail a été de développer un système nanoparticulaire original de polyamidoamine réticulé (PAA) capable de véhiculer des miARNs au niveau cellulaire et tissulaire. Dans un premier temps, un test basé sur l’expression de la luciférase a été mis au point afin d’étudier la cytotoxicité et l’efficacité de nanoparticules des miARNs. Dans un second temps,des nanoparticules PAA-miARN ont été développées. Différentes conditions de formulation ont été testées afin d’optimiser la complexation entre miARNs et polymères. En l’absence d’efficacité cellulaire significative des premiers objets obtenus, des modifications du procédé de formulation ont été apportées, permettant une plus grande stabilité et une meilleure efficacité. Une fonctionnalisation par greffage de groupements biotine à des complexes PAA thio-réticulés a amélioré l’efficacité des internalisations. En conclusion, ce travail a permis le développement d’une méthode simple et rapide pour l’évaluation de l’efficacité et de la cytotoxicité de nanoparticules de miARN. La stabilité des nanoparticules a été augmentée par réticulation de thiolet leur internalisation a été améliorée par le greffage,adapté et modulable, d’un ligand cellulaire. / Glioblastoma are aggressive brain tumours with a median survival of 15 months even with the best currently available treatment options. microRNAs (miRNA) are ~23 nucleotide natural silencing RNAs that have great potentials to improve cancer treatment outcomes. Lack of a safe, stable and efficient delivery system has, however, hindered the use of miRNAs inclinical applications. The aim is therefore to develop amiRNA delivery system adapted to glioblastoma using linear chain cationic polyamidoamine (PAA) polymers.The first part involved the development of luciferase assay that combined the measurement of gene-knockdown efficiency and cytotoxicity of miRNA nanoparticles. The simple two-step procedure was more effective and sensitive compared to the conventional protein-based normalization method. The second part was focused on the development of miRNA nanoparticles. In the initial phase, conditions required for maximum miRNA-polymer binding was achieved, however, the newly developed miRNA-PAA nanoparticlesdid not produce significant functional gene-knockdown after cell treatment. The second stage was focused on the optimization of nanoparticle formulation as a function of stability in physiologicalionic concentration. Stable PAA-nanoparticles displaying moderate cellular uptake and gene-knockdown were obtained. The final stage of development was focused on PAA-nanoparticle tagging with biotin, which improved their cellular uptake. This work developed simple and informative luciferase assay ; the stability of miRNA-PAA-nanoparticles was improved by thiol-crosslinking and the functional performance was strongly enhanced by a simple butsmart method of ligand tagging.

Orientador: Guilherme de Camargo Ferraz / Resumo: A descoberta de polímeros biodegradáveis influenciou a pesquisa biomédica. O poli (ácido lático) (PLA) e a Poli (Ɛ-caprolactona) (PCL) e suas blendas se tornaram foco de vários estudos por serem biodegradáveis e biorreabsorvíveis, particularmente em pesquisas envolvendo a implantação in vivo. Pelo presente, objetivou-se avaliar se o implante subcutâneo (SC) e intraperitoneal (IP) de PLA ou blenda PLA/ PCL são seguros, biocompatíveis e biodegradáveis em ratos machos Wistar. Os ratos foram distribuídos em cinco grupos avaliados em duas fases; aguda: -1, 1, 2, 7 e 14 dias e crônica: 2, 8 e 24 semanas após a implantação. Assim, estudaram se os grupos PLA (PLA puro), PLA/PCL (mistura PLA/PCL), instrumentado (GI), controle (C) e grupo controle inflamatório (CI). Para avaliar a biocompatibilidade utilizou-se teste comportamental de campo aberto (CA), filamentos de von Frey (FvF) e análises histopatológicas utilizando coloração de hematoxilina-eosina (HE) e picrosirius-hematoxilina (PSH). A biodegradação in vivo e degradação in vitro em solução de PBS a 37°C do PLA e PLA/PCL foram avaliadas por microscopia eletrônica de varredura (MEV). As comparações foram realizadas entre os grupos subdivididos conforme a implantação IP e SC. No teste CA, realizado dois dias após a implantação, o grupo CI demonstrou redução nas frequências de locomoção e levantar e aumento na frequência de grooming em relação aos grupos implantados PLA, PLA/PCL, GI pela via IP ou SC e grupo C. As avaliações de FvF ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The discovery of biodegradable polymers influenced biomedical research. Poly (lactic acid) (PLA) and poly (Ɛ-caprolactone) (PCL) and their blends have become the focus of several studies because they are biodegradable and bioreabsorbable, particularly in research involving implantation in vivo. The aim of this study was to evaluate whether the subcutaneous (SC) and intraperitoneal (IP) implantation of PLA or PLA / PCL blends are safe, biocompatible and biodegradable in male Wistar rats. The rats were distributed in five groups evaluated in two phases; acute: -1, 1, 2, 7 and 14 days and chronic: 2, 8 and 24 weeks after implantation. Thus, we studied whether the groups PLA (pure PLA), PLA / PCL (PLA / PCL mixture), sham (S), control (C) and inflammatory control group (IC). To evaluate the biocompatibility, the open field behavioral test (OF), von Frey filaments (FvF) and histopathological analyzes using hematoxylin-eosin (HE) staining and picrosirius-hematoxylin (PSH) were used. In vivo biodegradation and degradation in vitro in PBS solution at 37°C of PLA and PLA / PCL were evaluated by scanning electron microscopy (SEM). The comparisons were made between groups subdivided according to the IP and SC implementation. In the OF test, performed two days after implantation, the IC group demonstrated a reduction in the locomotion frequencies and augmentation and increase in the grooming frequency in relation to the PLA, PLA / PCL, sham implanted groups via IP or SC and C groups. FvF... (Complete abstract click electronic access below) / Mestre

Cette thèse porte sur la conception de carbonates cycliques originaux et d’amines dérivés des huiles végétales dans le but de synthétiser des poly(hydroxyuréthane)s entièrement bio-sourcés. D’une part, deux voies d’accès à des amines dérivées d’acides gras utilisant des conditions douces ont été étudiées. La première consiste en l’oxydation sous air d’alcools aliphatiques en nitriles en présence de TEMPO supporté sur silice, suivi par une hydrogénation des dinitriles en diamines. Egalement, des diènes dérivés d’acides gras ont été couplés à la cystéamine via une chimie thiol-ène, permettant l’accès à des diamines aliphatiques bio-sourcées. D’autre part, des carbonates cycliques substitués à 5 chaînons ont été synthétisés à partir de dérivés d’acides gras et de glycérol, dans le but d’augmenter leur réactivité vis-à-vis de l’aminolyse. En insérant un groupement fonctionnel éther, thio-éther ou ester en position α ou β des carbonates cycliques, la réactivité de ces derniers vis-à-vis des amines a pu être ajustée. L’étude de la sélectivité, des réactions secondaires et de la catalyse de la voie carbonate/amine a été menée afin de mieux appréhender cette voie d’accès à des polyuréthanes sans isocyanates. Des poly(hydroxyuréthane)s entièrement oléo-sourcés ont été synthétisés avec succès, montrant des propriétés physico-chimiques contrôlables selon la structure des monomères. / In this thesis, vegetable oils were used as a platform to design original cyclic carbonates and amines with the goal to synthesize fully bio-based poly(hydroxyurethane)s. On the one hand, two routes to fatty acid-based amines were implemented in mild conditions. First, the oxidation of aliphatic alcohols into nitriles was performed under air in the presence of supported TEMPO on silica, followed by hydrogenation of nitrile compounds into corresponding amines. Second, thiol-ene chemistry was performed on unsaturated fatty acid substrates to design original aliphatic bio-based diamines. On the other hand, substituted 5-membered cyclic carbonates were designed from fatty acids and glycerol derivatives to enhance their reactivity towards aminolysis. By inserting ether, thio-ether or ester functionalities in α- or β-position of the cyclic carbonates, their reactivity towards amines could be tuned. Investigations on the selectivity, side reactions and catalysis of the carbonate-amine reaction were carried out to apprehend this route to non-isocyanate polyurethanes. Fully vegetable oil-based PHUs with tunable physico-chemical properties with respect to the monomer structures could be easily achieved.

En dehors des effets cytostatiques ou cytotoxiques sur les cellules tumorales, certaines thérapies anti-cancéreuses peuvent déclencher la mort cellulaire immunogénique, libérant les signaux de danger pour alerter le système immunitaire. Les cellules T CD8+ T (Tc1) productrices d’IFN- et spécifiques de la tumeur sont nécessaires pour le succès de la chimiothérapie et la diminution de la croissance tumorale. L’amorçage d’une réponse bénéfique Tc1 dépend de la sécrétion d'IL-1β par les cellules dendritiques confrontées à des cellules tumorales traitées avec de l’anthracycline libérant de l’ATP. Pour identifier les composants inflammatoires qui lient les réponses immunitaires innées et adaptatives, nous avons analysé l'influence de la chimiothérapie immunogène sur le microenvironnement de la tumeur. Nous avons identifié une up-régulation de gènes associés à la réponse Th1 et Th17 dans un modèle de tumeur répondant au traitement par les anthracyclines par un retard de croissance. En interférant avec les voies IFN- ou l'IL-17A, l'effet thérapeutique de la doxorubicine et l'oxaliplatine a été aboli et le vaccin à base de cellules tumorales mortes ne protège plus les souris de la réintroduction de cellules tumorales vivantes. Nous avons également découvert que des sous-populations distinctes de lymphocytes T  (V4+ et V6+) colonisent des tumeurs peu de temps après la chimiothérapie, où ils ont proliféré et sont devenus producteurs majeurs de l’IL-17 au sein de la tumeur. Nous avons constaté une forte corrélation entre la présence de lymphocytes T  producteurs d’IL-17 ( T17) et de TIL CD8+ (Tc1) dans trois modèles différents de tumeurs traitées par la chimiothérapie ou la radiothérapie. IL-17A agit sur la signalisation en amont de l'IFN- puisqu’un défaut d’expression d’IL-17RA conduit à la perte complète de la production des Tc1 spécifiques de l’antigène. La contribution des cellules  T17 (V4+ et V6+) dans l’effet bénéfique de la chimiothérapie est essentielle puisque les souris V4/6-/-. L’axe IL-1β/IL-1R, mais pas IL-23/IL-23R, est essentielle pour la production d'IL-17 par les cellules T et l’effet bénéfique de la chimiothérapie. Le transfert adoptif de lymphocytes  T peut rétablir l'efficacité de la chimiothérapie dans le modèle de souris IL-17A-/- et améliorer l'effet de la chimiothérapie chez la souris wt, s'ils conservent l'expression de l'IL-1R et de l'IL-17A. Nos résultats suggèrent l’existence d’un axe fonctionnel: DC (IL-1β) → cellules T (IL-17) → Tc1 (IFN-), déclenché par la chimiothérapie induisant la mort des cellules tumorales, phénomène essentiel pour une réponse thérapeutique favorable. Pour renforcer la réponse immunitaire, nous essayons de combiner la chimiothérapie « immunogène » avec le vaccin anti-tumoral en présence d’adjuvants (poly (A:U), l'agoniste de TLR3).Ce type de thérapie séquentielle combinée, appelé VCT, pourrait retarder considérablement la croissance des tumeurs, voire l’éradiquer complètement et établir une protection spécifique à long terme. Pour décortiquer l'effet de la poly (A:U) sur le système immunitaire et sur les cellules tumorales exprimant le TLR3, nous avons effectué un traitement VCT chez la souris nude, TRIF-/- et les souris présentant une diminution de l’expression de TRIF au niveau des cellules tumorales. Ainsi l'effet anti-tumoral de VCT requiert les lymphocytes T et la voie de signalisation TRIF intacte au niveau de l'hôte et des cellules tumorales. Le traitement poly (A:U) peut induire un niveau élevé de production de certaines chimiokines associées à la réponse de type Th1 (CCL5 et CXCL10 ) par les cellules tumorales in vitro et in vivo, ce qui peut influencer négativement et positivement les résultats thérapeutiques. Le découplage de l’action de CCL5 et de XCL10, pourrait améliorer le traitement par la VCT. Notre étude souligne ainsi le rôle des facteurs inflammatoires dérivés de la tumeur et de l’hôte dans la régulation de la réponse immunitaire anti-tumorale. / Besides exerting cytostatic or cytotoxic effects on tumor cells, some anti-cancer therapies (anthracyclines, oxaliplatin, X-Rays) could trigger an immunogenic cell death modality, releasing danger signals to alert immune system. We have shown that tumor-specific IFN- producing CD8+ T cells (Tc1) are mandatory for the success of chemotherapy to prevent tumor outgrowth. Priming of Tc1 response depends on IL-1β secretion by DC confronted with anthracycline-treated tumor cells releasing ATP. To identify the inflammatory components which link innate and cognate immune responses, we analyzed the influence of immunogenic chemotherapy on tumor microenvironment. We found an upregulated Th1- and Th17-related gene expression pattern in growth-retarded tumor after anthracycline treatment. By interfering with IFN- or IL-17A pathways, therapeutic effect of doxorubicin and oxaliplatin was abolished and dying tumor cell-based vaccine lost its efficacy to protect mice from live tumor cell rechallenge. Interestingly, we discovered that distinct subsets of  T lymphocytes (V4+ and V6+) colonized tumors shortly after chemotherapy, where they proliferated and became the dominant IL-17 producers within tumor beds. In three tumor models treated with chemotherapy or radiotherapy, a strong correlation between the presence of IL-17-producing  T ( T17) and IFN--producing CD8+ TIL (Tc1) was discovered. IL-17A signaling acts as upstream of IFN- since defect in IL-17RA led to complete loss of antigen specific Tc1 priming. The contribution of  T17 cells (V4+ and V6+) to chemotherapy is critical as V4/6-/- mice showed reduced sensitivity to chemotherapy and vaccination. Also, tumor infiltrating  T17 and Tc1 cells were reduced to basal level in this strain. IL-1β/IL-1R, but not IL-23/IL-23R, is pivotal for IL-17 production by  T cells and the success of chemotherapy. Importantly, adoptive transfer of  T cells could restore the efficacy of chemotherapy in IL-17A-/- mice and ameliorate the effect of chemotherapy in wild type host, provided that they retain the expression of IL-1R and IL-17A. Our research suggest a DC (IL-1β) →  T cells (IL-17) → Tc1 (IFN-) immune axis triggered by chemotherapy-induced dying tumor cells, which is critical for the favorable therapeutic response. To boost the immune system, we try to combine immunogenic chemotherapy with tumor vaccine in the presence of TLR3 agonist Poly (A:U). This sequential combined therapy, which we named VCT, could significantly retard tumor growth or even completely eradicate tumor and establish long-term protection against rechallenge in highly tumorigenic models. To dissect the effect of Poly (A:U) on immune system and that on TLR3 expressing-tumor cells, we performed VCT treatment in nude mice, TRIF-/- mice and with TRIF-silencing tumors. Interestingly, our results suggested that anti-tumor effect of VCT required T cells and intact TRIF signaling pathway at the level of the host and that of tumor cells. Poly (A:U) treatment could induce high level of CCL5 and CXCL10 production from tumor cells both in vitro and in vivo, which could negatively and positively influence the therapeutic outcome. By uncoupling the effect of CCL5 from that of CXCL10, the VCT treatment can be ameliorated. Our study emphasizes that both tumor and host derived inflammatory factors participate in regulating anti-tumor response. We also highlight that therapeutic application of TLR agonists can be optimized through regulating the profile of chemokines and their downstream signaling events.