La stimulation à haute fréquence (SHF) du noyau subthalamique (NST) joue un rôle essentiel chez les patients Parkinsoniens dans l'amélioration des troubles moteurs pour lesquels la dopa-thérapie n'est plus satisfaisante. Tout comme l'administration à long terme de L-DOPA, la SHF du NST, peut aussi, selon l'intensité de stimulation, évoquer des mouvements dyskinétiques. Ces dyskinésies sont considérées comme un phénomène d'apprentissage moteur pathologique, secondaire à une altération de la transmission glutamatergique et sont sous-tendues par des modifications durables d'expression génique, notamment dans le striatum. L'objectif de ce travail de thèse est d'étudier et de comparer les mécanismes moléculaires des dyskinésies induites par la L-DOPA à celles induites par la SHF, en se focalisant plus particulièrement sur la sous unité NR2B des récepteurs NMDA. Dans un premier temps, nous avons montré par immunohistochimie que la sous unité NR2B est hyperphosphorylée dans le NST et l'EP suite à l'induction de dyskinésie par la SHF du NST chez l'animal sain. Ces résultats ont été confirmés par la suite dans un modèle animal de la maladie de Parkinson, le rat 6-OHDA. La comparaison de ces modifications avec celles observées chez le rat 6-OHDA rendus dyskinétique par un traitement chronique à la L-DOPA nous permet de suggérer que l'induction des dyskinésies est associée à une hyperphosphorylation de NR2B au sein d'une voie subthalamo-entopédonculaire alors qu'une activation de NR2B dans le striatum semble être impliquée dans l'expression des dyskinésies. Enfin, nos résultats mettent également en évidence une implication différentielle des deux structures de sorties des ganglions de la base dans les processus akinétiques et dyskinésiogènes. / High frequency stimulation of the subthalamic nucleus (STN-HFS) alleviates parkinsonian motor symptoms and indirectly improves dyskinesia by decreasing L-DOPA requirement. However, inappropriate stimulation can also trigger dyskinetic movements Dyskinesia are thought to be a pathological learning process due to an overactive glutamate transmission within the basal ganglia. Moreover, several molecular changes seem to be involved in this process. The aim of the present study is to compare the molecular mechanisms of dyskinesia induced by L-DOPA and by STN-HFS, by focusing more particularly on the NR2B-containing NMDA receptor. We show by immunohistochemistry that NR2B subunit is hyperphosphorylated within the STN and the EP during a dyskinesiogenic STN-HFS in normal rats. Similar results are obtained from 6-OHDA rats, a model of Parkinson disease. Comparison of these results with those observed in 6-OHDA dyskinetic rats chronically treated with L-DOPA suggest that dyskinesia induction is associated with an hyperphosphorylation of NR2B within a subthalamo-entopeduncular network while activation of NR2B within the striatum seem to be involved in the expression of dyskinesia. A different implication of the two output of the basal ganglia in akinetic and dyskinesiogenic process is also demonstrated. STAR Date de soutenance : 8 juillet 2011 Thèse sur travaux: non

Le traitement substitutif par la L-DOPA, indiqué dans la maladie de Parkinson, induit à terme des complications motrices appelées les dyskinésies induites par la L-DOPA. L'apparition des dyskinésies est due, au moins en partie, à la mise en place d'une plasticité aberrante dans le striatum, qui fait suite à des modifications transcriptionnelles induites par la L-DOPA. Une analyse du transcriptome nous a permis d'identifier le gène Nptx2, codant pour la neuropentraxine Narp, comme étant un candidat potentiellement impliqué dans l'apparition des dyskinésies. L'objectif de ce travail était d'étudier la régulation et le rôle de Narp dans l'apparition des dyskinésies, dans un modèle de souris lésée à la 6-hydroxydopamine. Nous avons montré que les dyskinésies induites par la L-DOPA sont diminuées chez des souris invalidées pour Nptx2 (Narp-KO). Par ailleurs, l'injection dans le striatum dorsal d'un adénovirus exprimant une forme dominante négative de Narp, induit une réduction importante des scores de dyskinésies. Dans le striatum, Narp est exprimé par les neurones épineux de taille moyenne et par les interneurones à parvalbumine. Après une stimulation dopaminergique, l'augmentation de l'expression de Nptx2 s'accompagne d'un enrichissement de Narp au niveau synaptique. Nos travaux montrent donc que Narp joue un rôle important dans le développement des dyskinésies et suggèrent qu'il pourrait être impliqué dans la plasticité synaptique des neurones du striatum, comme cela a été montré dans l'hippocampe. Ces résultats permettent d'ouvrir de nouvelles perspectives thérapeutiques pour retarder l'apparition de ces complications motrices chez les patients parkinsoniens. / Dopaminergic replacement therapy in Parkinson’s disease is hampered by the occurrence of L-DOPA-induced dyskinesia (LID). One major hypothesis is that LID result from L-DOPA-induced aberrant plasticity in the striatum due to modifications of the transcriptional program. Using a microarray-based approach, we identified Narp as a putative candidate implicated in LID induction. Thus, we investigated Narp involvement in LID by examining abnormal involuntary movements (AIM) development in Narp genetically-ablated mice or upon intrastriatal injection of a dominant negative form of Narp. Interestingly, the total AIM score was greatly reduced in these two models of impaired Narp expression. Hence, my results highlight Narp as an important actor in LID development. Then, I further examined Narp regulatory mechanisms in the striatum and I demonstrated that dopamine stimulation leads to increased Narp expression both at the transcriptional level and at the protein level through its accumulation within the synaptic compartment. These findings advance knowledge about mechanisms underlying dyskinesia with the hope of delaying their appearance in patients.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-09T22:44:45Z No. of bitstreams: 1 AntonioMarcosUrbanoDeAraujo_TESE.pdf: 3225313 bytes, checksum: e25ff75db18347413666f8caf426a50e (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-10T22:25:30Z (GMT) No. of bitstreams: 1 AntonioMarcosUrbanoDeAraujo_TESE.pdf: 3225313 bytes, checksum: e25ff75db18347413666f8caf426a50e (MD5) / Made available in DSpace on 2016-08-10T22:25:30Z (GMT). No. of bitstreams: 1 AntonioMarcosUrbanoDeAraujo_TESE.pdf: 3225313 bytes, checksum: e25ff75db18347413666f8caf426a50e (MD5) Previous issue date: 2016-01-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Foram sintetizados neste trabalho em solu??o aquosa os seguintes compostos de coordena??o: [Ni(LDP)(H2O)2Cl2].2H2O, [Co(LDP)Cl2].3H2O, [Ni(CDP)Cl2].4H2O, [Co(CDP)Cl2].4H2O, [Ni(BDZ)2Cl2].4H2O e [Co(BDZ)2Cl2].(H2O). Esses complexos foram sintetizados por adi??o estequiom?trica do ligante nas respectivas solu??es de cloretos do metal. A precipita??o ocorreu ap?s a secagem dos solventes sob temperatura ambiente. A caracteriza??o e proposta das estruturas foram realizadas utilizando-se de m?todos convencionais de an?lise tais como: an?lise elementar (CHN), espectroscopia de absor??o na regi?o do infravermelho com transformada de Fourier (FTIR), difratometria de raios X pelo m?todo do p? e as t?cnicas termoanal?ticas TG/DTG (termogravimetria/termogravimetria derivada) e DSC (calorimetria explorat?ria diferencial). Estas t?cnicas forneceram informa??es sobre desidrata??o, modos de coordena??o, comportamento t?rmico, composi??o e estrutura dos compostos sintetizados. Com os resultados das curvas TG, p?de-se estabelecer a f?rmula geral de cada composto sintetizado. Pela an?lise dos difratogramas de raios X foi observado que quatro dos complexos sintetizados apresentam estrutura n?o cristalina que foram os complexos obtidos a partir da L-dopa e Carbidopa e para os complexos obtidos a partir do benzimidazol obteve-se estruturas cristalinas. As observa??es dos espectros na regi?o do infravermelho sugeriram uma coordena??o monodentada do ligante aos respectivos centros met?licos atrav?s do grupo amina para todos os complexos. As curvas TG-DTG e DSC forneceram informa??es e importantes sobre o comportamento e a decomposi??o t?rmica dos compostos sintetizados. Os dados de condutividade molar apontaram que as solu??es dos complexos formados se comportam como um n?o-eletr?lito, o que implica dizer que o cloro est? coordenado ao ?tomo central nos complexos. / Were synthesized in this work in the following aqueous solution coordination compounds: [Ni(LDP)(H2O)2Cl2].2H2O, [Co(LDP)Cl2].3H2O, [Ni(CDP)Cl2].4H2O, [Co(CDP)Cl2].4H2O, [Ni(BDZ)2Cl2].4H2O and [Co(BDZ)2Cl2(H2O)2]. These complexes were synthesized by stoichiometric addition of the binder in the respective metal chloride solutions. Precipitation occurred after drying the solvent at room temperature. The characterization and proposed structures were made using conventional analysis methods such as elemental analysis (CHN), absorption spectroscopy in the infrared Fourier transform spectroscopy (FTIR), X-ray diffraction by the powder method and Technical thermoanalytical TG / DTG (thermogravimetry / derivative thermogravimetry) and DSC (differential scanning calorimetry). These techniques provided information on dehydration, coordination modes, thermal performance, composition and structure of the synthesized compounds. The results of the TG curve, it was possible to establish the general formula of each compound synthesized. The analysis of X-ray diffraction was observed that four of the synthesized complex crystal structure which does not exhibit the complex was obtained from Ldopa and carbidopa and the complex obtained from benzimidazole was obtained crystal structures. The observations of the spectra in the infrared region suggested a monodentate ligand coordination to metal centers through its amine group for all complexes. The TG-DTG and DSC curves provide important information and on the behavior and thermal decomposition of the synthesized compounds. The molar conductivity data indicated that the solutions of the complexes formed behave as a nonelectrolyte, which implies that chlorine is coordinated to the central atom in the complex.

Parkinson’s disease (PD) is a progressive neurodegenerative disorder producing a clinical syndrome of bradykinesia, rigidity and resting tremor. These motor symptoms appear due to the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc) and loss of dopamine in the striatum, which subsequently leads to an imbalance of the basal ganglia motor circuit. The most effective pharmacological treatment for PD is L-3,4-dihydroxyphenylalanine (L-DOPA), the immediate metabolic precursor of dopamine, which effectively restores motor function. L-DOPA is catabolised into dopamine and replaces neurotransmitter loss in PD. However, long-term L-DOPA treatment leads to abnormal involuntary movements (AIMs), such as L-DOPA-induced dyskinesia (LID), which reduces the quality of life in PD patients. Currently, there are no reliable pharmacological treatments for these motor complications. Clinical and preclinical studies have shown that development and expression of LID is linked to unregulated dopamine release and plasticity-induced changes of striatal dopaminergic and non-dopaminergic signalling pathways. The activities of these pathways can be modulated by neurotransmitter receptors of a specific classification, the G-protein-coupled receptor (GPCR) family. In turn, GPCRs are regulated by certain endogenous proteins, the regulators of G-protein signalling (RGS) proteins. Numerous RGS protein subtypes are expressed in the striatum but their roles in PD and LID remain poorly understood. Given the modulatory function of RGS proteins in the striatum, these endogenous factors may have pathophysiological roles in the expression of motor symptoms in PD and LID. The studies presented in this thesis investigated the roles of RGS proteins in the unilateral 6-hydroxydopamine (6-OHDA)-lesioned rat model of PD and LID. Rats received unilateral 6-OHDA lesions of the right medial forebrain bundle to induce severe dopamine denervation. L-DOPA/benserazide (6/15 mg/kg) was then administered once daily for at least 21 days to induce stable abnormal involuntary movements (AIMs). In Chapter 2 of this thesis, increased levels of RGS2 and RGS4 mRNA were found in the rostral striatum of the unilateral 6-OHDA-lesioned rat model of LID. Moreover, elevated levels of RGS4 mRNA were specific to sensorimotor regions and positively correlated with AIMs severity. These molecular and behavioural data suggest that RGS4 proteins are involved in the expression of LID. In Chapters 3 and 4, behavioural studies conducted in the unilateral 6-OHDA-lesioned rat model of LID showed that acute inhibition of striatal RGS4 proteins reduced the expression of AIMs and improved overall motor function. Moreover, repeated de novo treatment with RGS4 protein inhibitors, in combination with L-DOPA, attenuated the development of AIMs and reduced the overexpression of preproenkephalin-B, a molecular marker of LID. These behavioural and molecular data suggest that blockade of RGS4 proteins can reduce the induction of LID. In Chapter 5, in vivo microdialysis conducted in the unilateral 6-OHDA-lesioned rat model of LID showed that systemic administration of RGS4 protein inhibitors, in combination with L-DOPA, attenuated unregulated striatal dopamine efflux. These data suggest that RGS4 proteins may regulate specific G-protein coupled receptors, such as 5-HT1A receptors, that modulate striatal dopamine release. In conclusion, the work presented in this thesis shows that RGS4 proteins play a pathophysiological role in the expression and development of LID. These proteins could mediate regulation of key neurotransmitter receptors involved in LID, making them a potential therapeutic target for the development of future treatments.

L-3,4-dihyroxyphenylalanine (L-DOPA, levodopa) is a gold standard treatment of Parkinson's disease. Lately, it has been found that some of its deuterated analogues exhibit higher potency in the treatment; thus, they could replace L-DOPA. The subject of this thesis was a study of L-DOPA and its deuterated derivatives by the means of vibrational spectroscopy (Raman, ROA, IR, and VCD) and a comparison of the experimental results to a quantum mechanical simulations of the spectra. ROA and VCD are chiroptical methods, thus they are suitable for measurement of chiral molecules amongst which L-DOPA indeed belongs. Thanks to the quantum chemistry calculations, which yielded spectra with a very good agreement with the experiment, we were able to assign experimental spectral features to individual vibrational modes of the L-DOPA. The use of chiroptical techniques (mainly ROA) enabled an assignment of an absolute configuration of double deuterated derivative of L-DOPA, α,β-D2-L-DOPA. It reviled that it occurs in a (S-α,S-β)-enantiomeric form.

Parkinson’s disease (PD) is a devastating neurodegenerative disease and the second most prevalent after Alzheimer’s disease. The most characteristic hallmark of Parkinson’s is the presence of Lewy Bodies, clumps of aggregated α-synuclein protein, in the Substantia Nigra. While much has been said and theorized about α-synuclein, mitochondrial dysregulation in neurons of Parkinson’s patients is an equally important consideration due to the role that the mitochondria plays in supplying neurons with their energy needs through ATP. C. elegans is a non-vertebrate animal often used to study aging and neurodegenerative disease due to its simple, well characterized genome. This literature review aims to outline the genetic and some environmental factors that cause mitochondrial dysregulation leading to the progressive neurodegeneration witnessed in Parkinson’s, as modeled in C. elegans. Through a select review of studies done on C. elegans homolog of genes associated with mitochondrial function, this review aims to elucidate the mechanism by which each mutation not only causes the deficits seen in PD on its own but also how it interacts with other genes to worsen or alleviate symptoms. Ultimately, understanding these pathways and mechanism will be crucial to discovering and creating new therapeutic treatments and targets.

L-Dihydroxyphenylalanine (L-DOPA), the anti-parkinsonian drug affording the greatest symptomatic relief of parkinsonian symptoms, is still misunderstood in terms of its neurotoxic potential and the mechanism by which generated dopamine (DA) is able to exert an effect despite the absence of DA innervation of target sites in basal ganglia. This review summaries important aspects and new developments on these themes. On the basis of L-DOPA therapy in animal models of Parkinson's disease, it appears that L-DOPA is actually neuroprotective, not neurotoxic, as indicated by L-DOPAs reducing striatal tissue content of the reactive oxygen species, hydroxyl radical (HO•), and by leaving unaltered the extraneuronal in vivo microdialysate level of HO•. In addition, the potential beneficial anti-parkinsonian effect of L-DOPA is actually increased because of the fact that the basal ganglia are largely DA-denervated. That is, from in vivo microdialysis studies it can be clearly demonstrated that extraneuronal in vivo microdialysate DA levels are actually higher in the DA-denervated vs. the intact striatum of rats - owing to the absence of DA transporter (i.e., uptake sites) on the absent DA nerve terminal fibers in parkinsonian brain. In essence, there are fewer pumps removing DA from the extraneuronal pool. Finally, the undesired motor dyskinesias that commonly accompany long-term L-DOPA therapy, can be viewed as an outcome of L-DOPAs sensitizing DA receptors (D1-D5), an effect easily replicated by repeated DA agonist treatments (especially agonist of the D 2 class) in animals, even if the brain is not DA-denervated. The newest findings demonstrate that L-DOPA induces BDNF release from corticostriatal fibers, which in-turn enhances the expression of D3 receptors; and that this effect is associated with motor dyskinesias (and it is blocked by D3 antagonists). The recent evidence on mechanisms and effects of L-DOPA increases our understanding of this benefical anti-parkinsonian drug, and can lead to improvements in L-DOPA effects while providing avenues for reducing or eliminating L-DOPAs deleterious effects.

Human neurosphere stem cells offer promising potential for the treatment of neurodegenerative diseases. Their well characterized multi-potency of differentiating into neurons, astrocytes, and oligodendrocytes when exposed to the optimum exogenous growth factors make them an exciting area of study (38). Finding novel endogenous methods of modulating stem cell metabolism will allow for the safer treatment of various brain disorders (34). In this experiment, melatonin, N-acetylserotonin, L-tryptophan, and L-DOPA are added in three different concentrations to neurospheres suspended in HNSC/GBM media with less than optimal concentrations of exogenous epidermal growth factor (EGF) and fibroblast growth factor (FGF). The alamarBlue assay (resazurin) was chosen as the most suitable assay for measuring neurosphere metabolism. Metabolic neural stem cells would cause the greatest reduction of the oxidized alamarBlue reagent (resazurin?resorufin), which was detected by a fluorescent plate reader (39-41). The percent reduction in alamarBlue was calculated for all four molecules at three different concentrations and compared to controls without any molecule. Our results illustrate that there was no statistically significant difference at p<0.05 between the biological molecules and the control group except for two exceptions (labeled with asterisks on figures 3 and 5) L-DOPA at a 40 micromolar concentration after 4 hours of incubation and melatonin at a 40 micromolar concentration after 52 hours of incubation.

No description available.

Mes travaux de thèse concernent le rôle du récepteur D1 de la dopamine dans les dyskinésies L-dopa induites, effets secondaires extrêmement handicapants du traitement de la maladie de Parkinson. En condition de dénervation striatale mimant l’environnement de la maladie de Parkinson, le traitement chronique par la L-dopa entraine des altérations majeures du trafic intraneuronal et de la signalisation du récepteur D1 de la dopamine dans les principaux neurones cibles de la dopamine, les neurones épineux de taille moyenne du striatum. Il existe en particulier une hypersensibilisation des récepteurs D1 dans les neurones striataux, avec une abondance accrue à la membrane plasmique et une diminution du niveau d’expression de la protéine GRK6 (Protéine kinase des Récepteurs Couplés aux Protéines G 6), un des acteurs clefs des phénomènes de désensibilisation, en relation directe avec l’apparition des dyskinésies.C’est dans ce contexte que se situe mon travail de thèse qui a eu pour objectif de mettre à profit et/ou de développer différents modèles expérimentaux et outils « in vivo » et « in vitro ». Nous avons associé des techniques d’imagerie cellulaire et tissulaire à des approches comportementales, afin d’explorer certains des événements cellulaires et moléculaires à l’échelle du neurone striatal et des réseaux neuronaux, reliant le niveau d’expression du récepteur D1, sa compartimentation cellulaire, son trafic intraneuronal et les dyskinésies ou des conditions pharmacologiques équivalentes.Nous avons confirmé dans le modèle du rat lésé unilatéralement à la 6-OHDA, traité par la L-dopa et développant des mouvements anormaux analogues aux dyskinésies chez l’homme, que le récepteur D1 est anormalement abondant à la membrane plasmique des neurones du striatum, alors qu’il devrait être internalisé après stimulation par son ligand naturel, la dopamine. Nous avons mis en évidence que les mécanismes d’internalisation après stimulation par un agoniste restent néanmoins fonctionnels. Après administration de l’agoniste D1, chez les animaux dyskinétiques, l’abondance des récepteurs D1 augmente dans les compartiments notamment impliqués dans les mécanismes d’internalisation et de transport (vésicules) et de dégradation (corps multivésiculaires). Nous avons apporté une explication possible à cette abondance anormale et à ce défaut d’internalisation, en montrant qu’ils pourraient être dus à une hétérodimérisation entre les récepteurs D1 et D3. La co-activation des récepteurs D1 et D3 par la L-dopa favoriserait l’ancrage du récepteur D1 à la membrane plasmique des neurones striataux.Dans ce cadre, l’abord de l’étude de l’implication du protéasome dans la régulation de l’expression du récepteur D1 de la dopamine nous a semblé particulièrement important, sur la base des premières études soulignant l’implication de ce système catalytique dans le contrôle de l’activité et du métabolisme des récepteurs aux neurotransmetteurs. Nous avons révélé pour la première fois des liens entre l’activité catalytique du protéasome et la dynamique intraneuronale du récepteur D1 et plus particulièrement nous avons montré que son activité chymotrypsine-like est réduite de façon spécifique dans le striatum d’animaux dyskinétiques, comme une conséquence directe d’une déplétion en dopamine associée à une hyperstimulation dopaminergique.Nous avons testé en situation expérimentale une stratégie « thérapeutique » nouvelle en restaurant le mécanisme de désensibilisation homologue du récepteur D1 de la dopamine, par correction du déficit de la kinase GRK6 par transfert du gène correspondant via l’injection intrastriatale d’un vecteur lentiviral. Nous avons montré que cette approche permet de réduire considérablement la sévérité des dyskinésies dans les modèles rat et primate non-humain, analogues des dyskinésies chez l’homme et qu’elle restaure les effets thérapeutiques de la L-dopa. Ces effets sont la conséquence de la restauration des mécanismes de désensibilisation homologue : la surexpression de GRK6 entraîne l’internalisation spécifique des récepteurs D1. L’ensemble de nos résultats s’inscrit dans une démarche de recherche translationnelle menée depuis plusieurs années au laboratoire allant de la cellule au patient, avec pour but de transposer la compréhension des données expérimentales concernant les anomalies de l’expression du récepteur D1 de la dopamine en stratégies thérapeutiques dans les dyskinésies L-dopa induites. Nos investigations montrent qu’il est possible d’agir sur l’expression du récepteur D1 à la membrane plasmique des neurones striataux de manière indirecte, en manipulant trois co-activateurs de son métabolisme, pour espérer réduire « in fine » la sévérité des dyskinésies. / In my thesis work, I studied the role of dopamine D1 receptor in L-dopa induced dyskinesia, a debilitating complication of Parkinson's disease’s treatment. In condition of striatal denervation, that mimics the Parkinson's disease environment, chronic treatment with L-dopa leads to major alterations of intraneuronal trafficking and dopamine D1 receptor signaling in the major target of dopamine neurons, the striatal medium spiny neurons. In particularly, there is a D1 receptor hypersensitivity in striatal neurons, with an increased abundance of D1 receptor at the plasma membrane and a decreased level of GRK6 protein expression, a key actor in desensitization mechanism, directly related with the apparition of dyskinesia.In this context, I used different in vitro and in vivo experimental models and tools. I have associated cell and tissue imaging techniques and behavioural approaches in order to explore cellular and molecular events in striatal neuron and neuronal networks, linking the D1 receptor expression level, its cellular compartmentalization, its intraneuronal trafficking and the dyskinesia behaviour or equivalent pharmacological conditions.We confirmed in the rat analog of L-dopa-induced dyskinesia, i.e., the L-dopa-induced abnormal involuntary movements in unilaterally 6-hydroxydopamine (6-OHDA)-lesioned animals, that D1 receptor is abnormally abundant in the plasma membrane of neurons in the striatum, whereas it should be internalized after stimulation by its natural ligand, the dopamine. We showed that nevertheless the internalization mechanisms after agonist stimulation remains functional. After D1 agonist administration in dyskinetic animals, D1 receptor abundance increases in the cytoplasmic compartments involved in the internalization and transport (vesicles) and degradation (multivesicular bodies) mechanisms. Based on D3 receptor antagonist experiment, we propose that this abnormal abundance and this lack of internalization could be due to heterodimerization between the D1 and D3 receptors. D1 and D3 receptors co-activation by L-dopa might anchor D1 receptor at the plasma membrane of striatal neurons.In this context, analysis of proteasome involvement in the regulation of dopamine D1 receptor expression seemed particularly important, on the basis of the first studies underlying proteasome involvement in the activity and metabolism of neurotransmitter receptors. We demonstrated for the first time links between the proteasomal catalytic activity and D1 receptor intraneuronal dynamics and more particularly we showed that the proteasome chymotrypsin-like activity is reduced specifically in the striatum of dyskinetic animals, as a direct consequence of dopamine depletion associated with dopaminergic hyperstimulation.We tested in experimental condition, a new "therapeutic"strategy in order to restore the dopamine D1 receptor homologous desensitization mechanism, correcting the GRK6 kinase deficit by gene transfer through the intrastriatal injection of a lentiviral vector. We showed that this approach reduces significantly the dyskinesia severity in rat and non-human primate models and restores the L-dopa therapeutic effects. These effects are a consequence of the homologous desensitization mechanisms restoration : indeed GRK6 overexpression provokes specific D1 receptor internalization.Our results are part of a translational research conducted over several years in the laboratory from cell to patient, in order to translate our increased understanding of D1 receptor function abnormalities into therapeutic strategies for L-dopa induced dyskinesia. Our investigations show that it is possible to act on D1 receptor expression at the plasma membrane of striatal neurons via various routes, all resulting into diminished dyskinesia severity.