La maladie de Huntington (MH) est une affection neurodégénérative héréditaire dont la mutation conduit à une expansion anormale d’un segment polyglutamine dans la protéine Huntingtine (Htt). La Htt mutée, bien qu’ubiquitaire dans le cerveau, conduit à une neurodégénérescence préférentielle du striatum. Cette atteinte pourrait en partie s’expliquer par la présence de produits de gènes sélectivement exprimés dans le striatum. Le laboratoire étudie depuis plusieurs années l’implication potentielle de marqueurs moléculaires du striatum dans la vulnérabilité des neurones de cette structure cérébrale vis-à-vis de la Htt mutée. Durant ma thèse, j’ai étudié plus spécifiquement trois de ces marqueurs du striatum: l’ARN long intergénique non-codant Abhd11os et les protéines µ-crystalline (CRYM) et doublecortin-like kinase 3 (DCLK3). Une étude préliminaire avait montré l’effet neuroprotecteur de ces marqueurs du striatum contre la toxicité induite par un fragment court de la Htt mutée dans un modèle murin aigu de la MH. J’ai donc étudié plus en détails les caractéristiques de ces "modificateurs" de la MH, ainsi que les mécanismes moléculaires potentiels permettant d’expliquer leur effet neuroprotecteur dans un contexte de la MH. J’ai également mené une expérience de thérapie génique en surexprimant le marqueur striatal DCLK3 dans un modèle transgénique de la MH. Cette étude nous a permis de valider le haut potentiel thérapeutique de cette protéine.L’élucidation précise des mécanismes d’action de ces modificateurs de la MH reste encore à résoudre, mais plusieurs pistes sont maintenant possiblement envisagées par rapport à leurs caractéristiques moléculaires. Outre la découverte de candidats neuroprotecteurs qui pourrait permettre de développer de nouvelles cibles thérapeutiques, cette étude a permis d’envisager de nouvelles hypothèses permettant d’expliquer la vulnérabilité striatale dans la MH et de donner une vue d’ensemble des voies sur lesquelles il serait possible d’agir pour induire des effets neuroprotecteurs dans ce contexte. / Huntington’s disease (HD) is a neurodegenerative disorder caused by the mutation of huntingtin (Htt) gene, which leads to an abnormal polyglutamine expansion in the Htt protein.Whereas mutant Htt (mHtt) is ubiquitously expressed in the brain, it preferentially affects the striatum. Our hypothesis is that genes products selectively expressed in the striatum could be involved in the high vulnerability of the striatum. From this hypothesis, numerous teams studied “markers of the striatum”, that are genes product enriched in the striatum whose expression are up- or down-regulated in HD compared to healthy condition.During my thesis, I studied three of these striatal markers: the long intergenic non-coding RNA Abhd11os, and the two proteins µ-crystallin (CRYM) and doublecortin-like kinase 3 (DCLK3). A preliminary study from the laboratory has shown that these three markers have neuroprotective effects against a toxic fragment of mHtt in vivo. So, the aims of my thesis were to further characterize these three ill-defined disease modifiers and to better understand the putative molecular mechanisms underlying their neuroprotective effects against mHtt.I also conducted a translational study on DCLK3, whose results validate the high therapeutic potential of this protein.The elucidation of the mechanisms underlying the neuroprotective effects of these disease modifiers against mHtt toxicity will require further studies, but new trails can be envisioned, according to their characteristics. My study has enlightened new therapeutic targets and more globally gives an overview of molecular mechanisms to modulate to induce neuroprotective effects in this context, leading to new hypothesis explaining striatal vulnerability in HD.

There is no abstract available for this thesis.

Introdução: A doença de Huntington (HD) é uma doença neurodegenerativa, autossômica dominante, causada pela expansão CAG que resulta em distúrbios do movimento, prejuízo cognitivo e alterações de personalidade. Muito pouco se sabe sobre a qualidade de vida de pacientes com HD e fatores associados e a influência dos mesmos nos sintomas depressivos dos cuidadores. Objetivo: Avaliar a qualidade de vida de indivíduos portadores da HD bem como suas implicações e, além disso, avaliar presença de sintomas depressivos no seu cuidador de convívio diário. Investigar os fatores que possam estar relacionados com o prejuízo da qualidade de vida do paciente tais como grau de comprometimento funcional, distúrbio motor, cognitivo e comportamental, sintomas de depressão, prejuízo no sono. Metodologia: Trata-se de um estudo quantitativo transversal. A população foi composta por pacientes com HD em acompanhamento no ambulatório de Distúrbios do Movimento e Neurogenética, que possuíam diagnóstico de HD confirmado por teste molecular. As entrevistas foram realizadas com auxilio de ferramentas estruturadas, as quais seguem: SF-36 e HQoLI, para qualidade de vida; UHDRS para avaliação funcional; MoCA para avaliação cognitiva; PSQI para avaliação do sono e BDI para avaliação de sintomas depressivos do paciente e cuidador. Resultados: Foram avaliados 28 pacientes com HD com idade média de 41 ± 9.5 e expansão CAG média de 45 ± 6. A duração da doença apresentou associação com os aspectos físicos da escala SF-36 (p<0.01). AUHDRS apresentou impacto em vários domínios da qualidade de vida, tais como domínios de saúde física e mental. A má qualidade do sono avaliada através da escala PSQI influenciou na QV do paciente nos dois grandes domínios de saúde física e saúde mental com (p<0.05) e (p<0.01) respectivamente. O nível cognitivo apresentado pelos pacientes avaliados pela escala MoCA apresentaram associação com domínio de funcionamento físico da escala SF-36 (p<0.01) Conclusão: As análises dos dados coletados permitem afirmar que se trata de uma doença que impacta de maneira significativa na QV das famílias. O apoio multidisciplinar a família afetada e o tratamento das comorbidades associadas se faz fundamental para amenizar os impactos da doença e melhorar a QV. / Background: The Huntington Disease (HD) is a neurodegenerative autosomal dominant disorder caused by the CAG expansion resulting in movement disorders, cognitive impairment and personality changes. Very little is known about the quality of life in HD patients associated factors and influence on depressive symptoms of caregivers. Objective: To evaluate the quality of life in individuals with HD, as well as its implications, and evaluate their daily caregiver for depressive symptoms. Factors that may be related to harm of patient's quality of life, such as functional impairment; motor, cognitive and behavioral disorder; symptoms of depression; and sleep loss were investigated. Methods: It is a quantitative cross-sectional study. The population was composed of patients with HD from Movement Disorders and Neurogenetics Clinic, who had positive molecular test. The interviews were carried out with support of the structured tools as follow: SF-36 and HQoLI for quality of life, UHDRS for functional evaluation, MoCA for cognitive evaluation, PSQI for sleep evaluation, and BDI for evaluation of depression of patient and caregiver. Results: Twenty-eight HD patients were evaluated with an average age of 41 ± 9.5 and an average CAG expansion of 45 ± 6. The duration of the disease was associated with the physical aspects of the SF-36 scale (p<0.01). UHDRS was associated with impairment in several domains of quality of life including mental and physical domains. It was identified that the bad sleep quality evaluated through the PSQI scale was associated with patient's QL (quality of life). The cognitive level evaluated by the MoCA scale presented association with the Physical functioning domain of SF-36 scale (p<0.01). Conclusion: The analysis of the collected data allows to affirm that HD impacts significantly on the families quality of life. The multidisciplinary support to the affected family is critical to mitigate the impacts of the disease and improve the QL.

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Introdução: A doença de Huntington (HD) é uma doença neurodegenerativa, autossômica dominante, causada pela expansão CAG que resulta em distúrbios do movimento, prejuízo cognitivo e alterações de personalidade. Muito pouco se sabe sobre a qualidade de vida de pacientes com HD e fatores associados e a influência dos mesmos nos sintomas depressivos dos cuidadores. Objetivo: Avaliar a qualidade de vida de indivíduos portadores da HD bem como suas implicações e, além disso, avaliar presença de sintomas depressivos no seu cuidador de convívio diário. Investigar os fatores que possam estar relacionados com o prejuízo da qualidade de vida do paciente tais como grau de comprometimento funcional, distúrbio motor, cognitivo e comportamental, sintomas de depressão, prejuízo no sono. Metodologia: Trata-se de um estudo quantitativo transversal. A população foi composta por pacientes com HD em acompanhamento no ambulatório de Distúrbios do Movimento e Neurogenética, que possuíam diagnóstico de HD confirmado por teste molecular. As entrevistas foram realizadas com auxilio de ferramentas estruturadas, as quais seguem: SF-36 e HQoLI, para qualidade de vida; UHDRS para avaliação funcional; MoCA para avaliação cognitiva; PSQI para avaliação do sono e BDI para avaliação de sintomas depressivos do paciente e cuidador. Resultados: Foram avaliados 28 pacientes com HD com idade média de 41 ± 9.5 e expansão CAG média de 45 ± 6. A duração da doença apresentou associação com os aspectos físicos da escala SF-36 (p<0.01). AUHDRS apresentou impacto em vários domínios da qualidade de vida, tais como domínios de saúde física e mental. A má qualidade do sono avaliada através da escala PSQI influenciou na QV do paciente nos dois grandes domínios de saúde física e saúde mental com (p<0.05) e (p<0.01) respectivamente. O nível cognitivo apresentado pelos pacientes avaliados pela escala MoCA apresentaram associação com domínio de funcionamento físico da escala SF-36 (p<0.01) Conclusão: As análises dos dados coletados permitem afirmar que se trata de uma doença que impacta de maneira significativa na QV das famílias. O apoio multidisciplinar a família afetada e o tratamento das comorbidades associadas se faz fundamental para amenizar os impactos da doença e melhorar a QV. / Background: The Huntington Disease (HD) is a neurodegenerative autosomal dominant disorder caused by the CAG expansion resulting in movement disorders, cognitive impairment and personality changes. Very little is known about the quality of life in HD patients associated factors and influence on depressive symptoms of caregivers. Objective: To evaluate the quality of life in individuals with HD, as well as its implications, and evaluate their daily caregiver for depressive symptoms. Factors that may be related to harm of patient's quality of life, such as functional impairment; motor, cognitive and behavioral disorder; symptoms of depression; and sleep loss were investigated. Methods: It is a quantitative cross-sectional study. The population was composed of patients with HD from Movement Disorders and Neurogenetics Clinic, who had positive molecular test. The interviews were carried out with support of the structured tools as follow: SF-36 and HQoLI for quality of life, UHDRS for functional evaluation, MoCA for cognitive evaluation, PSQI for sleep evaluation, and BDI for evaluation of depression of patient and caregiver. Results: Twenty-eight HD patients were evaluated with an average age of 41 ± 9.5 and an average CAG expansion of 45 ± 6. The duration of the disease was associated with the physical aspects of the SF-36 scale (p<0.01). UHDRS was associated with impairment in several domains of quality of life including mental and physical domains. It was identified that the bad sleep quality evaluated through the PSQI scale was associated with patient's QL (quality of life). The cognitive level evaluated by the MoCA scale presented association with the Physical functioning domain of SF-36 scale (p<0.01). Conclusion: The analysis of the collected data allows to affirm that HD impacts significantly on the families quality of life. The multidisciplinary support to the affected family is critical to mitigate the impacts of the disease and improve the QL.

Introdução: A doença de Huntington (HD) é uma doença neurodegenerativa, autossômica dominante, causada pela expansão CAG que resulta em distúrbios do movimento, prejuízo cognitivo e alterações de personalidade. Muito pouco se sabe sobre a qualidade de vida de pacientes com HD e fatores associados e a influência dos mesmos nos sintomas depressivos dos cuidadores. Objetivo: Avaliar a qualidade de vida de indivíduos portadores da HD bem como suas implicações e, além disso, avaliar presença de sintomas depressivos no seu cuidador de convívio diário. Investigar os fatores que possam estar relacionados com o prejuízo da qualidade de vida do paciente tais como grau de comprometimento funcional, distúrbio motor, cognitivo e comportamental, sintomas de depressão, prejuízo no sono. Metodologia: Trata-se de um estudo quantitativo transversal. A população foi composta por pacientes com HD em acompanhamento no ambulatório de Distúrbios do Movimento e Neurogenética, que possuíam diagnóstico de HD confirmado por teste molecular. As entrevistas foram realizadas com auxilio de ferramentas estruturadas, as quais seguem: SF-36 e HQoLI, para qualidade de vida; UHDRS para avaliação funcional; MoCA para avaliação cognitiva; PSQI para avaliação do sono e BDI para avaliação de sintomas depressivos do paciente e cuidador. Resultados: Foram avaliados 28 pacientes com HD com idade média de 41 ± 9.5 e expansão CAG média de 45 ± 6. A duração da doença apresentou associação com os aspectos físicos da escala SF-36 (p<0.01). AUHDRS apresentou impacto em vários domínios da qualidade de vida, tais como domínios de saúde física e mental. A má qualidade do sono avaliada através da escala PSQI influenciou na QV do paciente nos dois grandes domínios de saúde física e saúde mental com (p<0.05) e (p<0.01) respectivamente. O nível cognitivo apresentado pelos pacientes avaliados pela escala MoCA apresentaram associação com domínio de funcionamento físico da escala SF-36 (p<0.01) Conclusão: As análises dos dados coletados permitem afirmar que se trata de uma doença que impacta de maneira significativa na QV das famílias. O apoio multidisciplinar a família afetada e o tratamento das comorbidades associadas se faz fundamental para amenizar os impactos da doença e melhorar a QV. / Background: The Huntington Disease (HD) is a neurodegenerative autosomal dominant disorder caused by the CAG expansion resulting in movement disorders, cognitive impairment and personality changes. Very little is known about the quality of life in HD patients associated factors and influence on depressive symptoms of caregivers. Objective: To evaluate the quality of life in individuals with HD, as well as its implications, and evaluate their daily caregiver for depressive symptoms. Factors that may be related to harm of patient's quality of life, such as functional impairment; motor, cognitive and behavioral disorder; symptoms of depression; and sleep loss were investigated. Methods: It is a quantitative cross-sectional study. The population was composed of patients with HD from Movement Disorders and Neurogenetics Clinic, who had positive molecular test. The interviews were carried out with support of the structured tools as follow: SF-36 and HQoLI for quality of life, UHDRS for functional evaluation, MoCA for cognitive evaluation, PSQI for sleep evaluation, and BDI for evaluation of depression of patient and caregiver. Results: Twenty-eight HD patients were evaluated with an average age of 41 ± 9.5 and an average CAG expansion of 45 ± 6. The duration of the disease was associated with the physical aspects of the SF-36 scale (p<0.01). UHDRS was associated with impairment in several domains of quality of life including mental and physical domains. It was identified that the bad sleep quality evaluated through the PSQI scale was associated with patient's QL (quality of life). The cognitive level evaluated by the MoCA scale presented association with the Physical functioning domain of SF-36 scale (p<0.01). Conclusion: The analysis of the collected data allows to affirm that HD impacts significantly on the families quality of life. The multidisciplinary support to the affected family is critical to mitigate the impacts of the disease and improve the QL.

O objetivo deste trabalho foi caracterizar as alterações de linguagem na doença de Huntington e correlacioná-las com os transtornos motores, cognitivos, psiquiátricos e, também, com o tempo de doença. Foram estudados 26 indivíduos, divididos em grupo leve (11 doentes) e moderado (15 doentes), comparados com dois grupos controle. Foram encontradas alterações em provas de compreensão e expressão da linguagem oral e gráfica para os dois grupos de doentes. Evidências sugerem que não há prejuízo nas representações semânticas, e que as dificuldades de linguagem estão relacionadas com o declínio cognitivo global e, especialmente, com o prejuízo das funções executivas. As alterações de linguagem se correlacionaram com o desempenho em tarefas cognitivas, mas não com as alterações motoras ou psiquiátricas da doença. Também não foi encontrada correlação entre o desempenho de linguagem e o tempo de doença / The objective of this study was to characterize the language alterations in Huntington's disease and how they relate to severity of motor, cognitive, psychiatric disturbances and also with the disease duration. Twenty-six (26) individuals were divided into groups characterized as lightly (11) and moderately ill (15) and compared with two control groups. Alterations in exams of language comprehension and expression were noticed for both groups of sick individuals. The result indicates no evident loss in semantic representation. The language difficulties are related to a global cognitive decline and, principally, to loss of executive functions. The language alterations were significantly correlated to performance in cognitive tasks, but not to the motor or psychiatric alterations of the disease. There was also no correlation observed between the language performance and duration of illness

La maladie de Huntington (MH) est une maladie neurodégénérative héréditaire qui affecte le cerveau. Cette maladie est caractérisée par des signes cliniques tels que la dépression, la démence ainsi que des troubles moteurs s’aggravant au fil du temps. Ces déficiences sont dues à une augmentation anormale de la taille des répétitions CAG dans le gène codant la protéine huntingtine. Celle-ci s’accumule dans les cellules cérébrales et entraine leur mort. Des études antérieures ont démontré que le profil métabolique mesuré en spectroscopie RMN ¹H pouvait être altéré chez les patients atteints de cette maladie ainsi que des atrophies majeures de certaines structures du cerveau. Des hypothèses impliquant des défauts du métabolisme énergétique ont été avancées pour expliquer en partie la physiopathologie de la maladie. Les acteurs du métabolisme pourraient ainsi constituer des biomarqueurs d’intérêt. A l'aide d'une modalité d'IRM prometteuse appelée CEST (Chemical Exchange Saturation Transfer : Transfert de Saturation par Echange Chimique) il est possible de détecter des protons labiles faiblement concentrés qui sont classiquement indétectables en IRM. Il devient ainsi possible de cartographier in vivo la distribution de métabolites comme le glutamate (qui est un neurotransmetteur) ou le glucose (qui est le carburant des cellules) qui sont potentiellement impliqués dans les maladies neurodégénératives. Les développements méthodologiques effectués lors de cette thèse ont ensuite été appliqués à des modèles de rongeurs de la maladie de Huntington (souris KI140, souris R6/1, rats BACHD) afin d'identifier les biomarqueurs potentiels de la pathologie et d'évaluer la pertinence de ces méthodes IRM innovantes. L’ensemble de ces résultats et des méthodes mises en place durant cette thèse montrent le potentiel de l’imagerie CEST pour l’étude des maladies neurodégénératives. / Huntington's disease (HD) is a inherited neurodegenerative disease affecting the brain. This disease is characterized by clinical symptoms such as psychiatric, cognitive and motor disorders worsening over time. These deficiencies are due to an abnormal increase in the size of the CAG repeats in the gene encoding the huntingtin protein. Thisaccumulates in the brain cells and causes their death. Previous studies have shown that the metabolic profile measured in ¹H NMR spectroscopy can be altered in patients with this disease as well as major atrophy of certain structures of the brain. Hypotheses involving defects in energy metabolism have been advanced to explain partially the pathophysiology of the disease. The metabolic actors could thus be biomarkers of interest. Using a promising MRI modality called Chemical Exchange Saturation Transfer (CEST), it is possible to detect low-concentrated labile protons that are classically undetectable in MRI. It thus becomes possible to map in vivo the distribution of metabolites such as glutamate (which is a neurotransmitter) or glucose (which is the fuel of cells) which are potentially involved in neurodegenerative diseases. The methodological developments carried out during this thesis were then applied to rodent models of Huntington's disease (KI140 mice, R6/1 mice, BACHD rats) in order to identify potential biomarkers of the pathology and to evaluate the relevance of these innovative MRI methods. All of these results and methods implemented during this thesis show the potential of CEST imaging for the study of neurodegenerative diseases.

La maladie de Huntington (MH) est une maladie neurodégénérative avec une transmission dominante, qui entraîne la mort dans les 15 à 20 ans suivant les premiers signes pathologiques. Le gène muté dans la MH contient une répétition de trinucléotide CAG instable qui code pour une expansion de polyglutamine (polyQ) dans la protéine huntingtine (HTT). Lorsque le gène code pour une protéine avec plus de 35 glutamines, il déclenche un dysfonction puis une mort neuronale notamment dans le striatum et le cortex, entrainant l'apparition de symptômes cognitifs, psychiatriques et moteurs. HTT est exprimée dans de nombreux tissus et est impliquée dans diverses fonctions cellulaires. Il est admis que dans la MH, l'expansion polyQ conduit à un gain de nouvelles fonctions toxiques, mais également à une perte des fonctions neuroprotectrices de HTT sauvage. Avant même l'apparition des premiers symptômes, des dysfonctions existent au sein du réseau neuronal corticostriatal. Cependant, les études in vivo des dysfonctions précoces au sein de ce réseau sont techniquement difficiles à l’échelle cellulaire.Le premier enjeu de ma thèse a été de reconstituer et de caractériser in vitro le réseau corticostriatal. Pour cela nous avons utilisé une plateforme microfluidique, compatible avec de la vidéomicroscopie haute résolution, dans laquelle chaque compartiment est identifié et où la progression de la croissance axonale à la formation des synapses est régulée. Nous avons observé des défauts majeurs au sein des différents compartiments du réseau corticostriatal, de la dynamique présynaptique à des défauts de structure et de transmission synaptiques, ainsi que des dysfonctions du trafic et des voies de signalisation post-synaptique. De manière intéressante, nous avons montré que le statut génétique du compartiment présynaptique était nécessaire et suffisant pour altérer ou restaurer le réseau corticostriatal.Le second aspect de ma thèse a été d’étudier la dynamique intracellulaire, depuis le réticulum endoplasmique jusqu’au compartiment final, au sein de cellules modèles de la MH. Pour cela nous avons utilisés le système RUSH (Retention Using Selective Hooks) couplé à une molécule utilisant la voie standard de biosynthèse des protéines. Au sein de cellules modèles de la MH, la dynamique intracellulaire est perturbée. L’utilisation de molécules inhibitrices d’une classe d’enzyme au sein de cellules modèles de la MH, est capable de restaurer une dynamique intracellulaire. En particulier, grâce au système microfluidique, nous avons montré qu’une molécule a la capacité de restaurer un réseau corticostriatal sauvage. Les études pharmacologiques de passage ont montré que cette molécule a un haut pouvoir de passage de la barrière hémato encéphalique. Le traitement pendant un mois de souris modèles de la MH et l’analyse de leur coordination motrice et de leur état anxiodépressif suggère que cette molécule est capable d’améliorer les symptômes chez les souris MH.Ces travaux ont permis de mettre en évidence 1/ l’importance du cortex comme région d’intérêt thérapeutique dans la MH, et 2/ le trafic de protéines comme une nouvelle cible thérapeutique. / Huntington Disease (HD) is a mid-life onset inherited neurodegenerative disorder that leads to death within 15 to 20 years after appearance of the first symptoms. The defective gene in HD contains an unstable trinuocleotide CAG repeat which encodes for a polyglutamine stretch (polyQ) in the huntingtin (HTT) protein. When the number of glutamines coded by the gene exceeds 35 repeats, it triggers neuronal dysfunction and death, affecting in particular the striatum and the cortex, causing cognitive, psychiatric, and motor symptoms. HTT is widely expressed and it is involved in numerous functions. In HD, it is accepted that, the polyQ strech leads to a gain of toxic functions, and converselyto a loss of neuroprotective functions of wild-type HTT. Long before the appearance of the first symptoms, dysfunctions exist within the corticostriatal neuronal network. However, in vivo studies of early cell dysfunction in this network are technically difficult, especially at the subcellular resolution.The first objective of my thesis was to reconstitute and characterize the corticostriatal network in vitro. We used a microfluidic device in which each neuronal compartment is identified and in which the progression from axonal growth to synapse regulation is controlled. We observed major defects in the different compartments of the corticostriatal circuit, from presynaptic dynamics to synaptic structure and transmission and to postsynaptic traffic and signaling. Importantly, the genetic status of the presynaptic compartment was necessary and sufficient to alter or restore the circuit.The second aspect of my thesis was to study the intracellular dynamics, from the endoplasmic reticulum to the final compartment, in cellular models of HD. For this we used the RUSH system (Retention Using Selective Hooks) coupled to a molecule using the standard pathway of protein biosynthesis. In cellular models of HD, intracellular dynamics are disrupted. We found that molecules targeting enzyme protein trafficking restore intracellular dynamics in HD cells. In particular, thanks to the microfluidic system, we showed that a given molecule has the capacity to restore a HD mutant corticostriatal network. Pharmacological studies showed that this molecule has a high power of passage of the blood brain barrier. One month treatment of HD mouse models and their behavioral tests for motor and anxiety-depressive symptoms suggest that the molecule is able to ameliorate symptoms.These studies made it possible to highlight 1 / the importance of the cortex as a key region of therapeutic interest in HD, and 2 / protein trafficking as a new therapeutic target in HD.

La maladie de Huntington (MH) est une maladie autosomale dominante causée par une expansion de la répétition CAG codant pour une expansion de la polyglutamine dans le premier exon du gène Huntingtine (HTT). Ce gène code pour une protéine ubiquitaire dont la mutation entraine de graves symptômes moteurs, psychiatriques et cognitifs, dus à la dégénérescence spécifique des neurones GABAergique épineux moyens du striatum. Nous proposons d'utiliser le trans-épissage pour développer un vecteur de thérapie génique qui réduira significativement voir éliminera l'expression de la protéine mutée tout en restaurant un niveau physiologique de HTT normale dans les cellules affectées par la mutation du gène Huntingtine. Cette technologie est basée sur le remplacement de l'exon muté par un exon sans mutation pendant l'étape de maturation de l'ARNm. Du fait du caractère dominant de la mutation,l'efficacité thérapeutique nécessitera une réaction de trans-épissage très efficace capable de convertir une portion significative de pre-ARNm HTT mutés en en ARNm HTT normaux. Nous avons donc développé un système rapporteur fluorescent permettant la détection des évènements de trans-épissage afin d’identifier les séquences les plus performantes parmi une centaine de molécules candidates. Nous avons validé notre stratégie de criblage basée sur la fluorescence et réalisé le criblage sur plusieurs introns HTT (3, 9 et 20) qui ont démontré des zones favorables au trans-épissage. Une méthode de quantification directe et absolue du taux de trans-épissage a également été validée pour déterminer très précisément le taux de correction. L’ensemble de ce travail a permis de contribuer à la mise en évidence de la faisabilité du trans-épissage dans le contexte de la MH. / Huntington’s disease (HD) is an autosomal dominant genetic disorder caused by the expansion of a CAG repeat encoding a polyglutamine tract in the first exon of the Huntingtin gene (HTT). This gene encode a ubiquitous protein in which mutation lead to severe motor, psychiatric and cognitive deficits and causes degeneration of specific neuronal populations, in particular the GABAergic medium spiny neurons of the striatum. We propose to use trans-splicing to develop a gene therapy vector that will significantly reduce or eliminate the expression of the mutant protein while restoring a physiological level of normal HTT in cells affected by the HD mutation. This technology is based on replacement of the mutated exon by a normal version during the mRNA maturation process. HTT mutation being dominant, therapeutic benefits necessitates a highly efficient trans-splicing reaction that would convert a significant proportion of mutant-HTT pre-mRNA into normal HTT mRNA. For this purpose, we developed a fluorescent reporter system enabling the detection of trans-splicing events in high content screening in order to identify the most potent trans-splicing sequences among hundreds of molecules. We validated our fluorescent screening strategy and implement trans-splicing screening on 3 HTT introns (3, 9 and 20), in which we demonstrated the presence of hotspot promoting trans-splicing reactions. A direct and absolute quantification method was also validated to accurately assess the correction rate. Overall, this work generated additional evidences of trans-splicing feasibility in HD.