L'objectif de mon travail a été d'étudier les bases génétiques de deux maladies du mouvement, les mouvements miroirs congénitaux (CMM) et les dyskinésies paroxystiques kinésigéniques (PKD). Nous avons tout d'abord mis en évidence le deuxième gène impliqué dans les CMM, RAD51, et commencé à explorer quelques hypothèses physiopathologiques. Nous avons ensuite recueilli les ADN de 26 cas index de CMM isolés, et montré que près de 50% d'entre eux avaient un variant possiblement pathogène dans RAD51 ou dans le premier gène de CMM décrit, DCC. Nous avons ensuite écarté l'implication d'un troisième gène possiblement causal, DNAL4, dans 17 cas index. Enfin, nous avons collaboré avec une équipe néo-zélandaise et mis en évidence par séquençage de l'exome un nouveau gène, NTN1, codant pour le ligand de DCC, dans deux familles et un cas sporadique. En ce qui concerne les PKD, nous avons analysé le premier gène impliqué dans cette pathologie, PRRT2, dans une cohorte de 42 cas index. Nous avons ainsi montré que PRRT2 est un gène majeur de PKD dans la population européenne, impliqué dans 65% des cas typiques. Nous avons ensuite contribué à mettre en évidence l'implication de PRRT2 dans la migraine hémiplégique, et effectué une revue de la littérature montrant que les mutations de PRRT2 peuvent être responsables de phénotypes multiples de mouvements anormaux paroxystiques. Nous avons ensuite réalisé un séquençage d'exomes chez une famille et 10 trios, malheureusement sans résultat probant. Enfin, chez deux patients avec PKD atypiques, nous avons mis en évidence des mutations du gène ADCY5, récemment impliqué dans des formes complexes de dyskinésies paroxystiques. / The objective of my work was to study the genetic bases of two movement disorders, congenital mirror movements (CMM) and paroxysmal kinesigenic dyskinesia (PKD). First we uncovered the second gene implicated in CMM, RAD51, and started to explore pathophysiological hypotheses. Then we collected DNA of 26 index cases of isolated CMM, and showed that almost 50% of them had a possibly pathogenic variant in RAD51 or in the first described gene of CMM, DCC. We subsequently ruled out the implication of a possible third gene, DNAL4, in 17 cases. Finally, we collaborated with a team from New Zealand to implicate a novel gene, NTN1, coding for the ligand of DCC, in two families and one sporadic case. Concerning PKD, we analyzed the first causative gene described, PRRT2, in a cohort of 42 index cases. We showed that PRRT2 is a major gene of PKD in the European population, involved in 65% of typical cases. We then contributed to show the implication of PRRT2 mutations in hemiplegic migraine, and conducted a review of the literature concluding that PRRT2 mutations can induce multiple types of paroxysmal disorders. We sequenced the exomes of one family and 10 trios negative for PRRT2, but were unable to uncover another causative gene. Finally, in two patients with atypical PKD, we found mutations in ADCY5, a gene recently implicated in complex forms of paroxysmal dyskinesia.

Tardive dyskinesia (TD), a movement disorder produced by long-term treatment with a classical antipsychotic drug, is generally considered to be a disorder of dopamine (DA) systems, since classical antipsychotics are potent DA D2 receptor blockers. Also, acute DA D1 agonist treatment of rats is known to produce vacuous chewing movements (VCMs), a behavioral feature resembling the oral dyskinesia that is so prominent in most instances of TD. In this paper we outline a series of studies in a new animal model of TD in which DA D1 receptor supersensitivity was produced by neonatal 6-hydroxydopamine (6-OHDA)-induced destruction of nigrostriatal DA fibers. In rats so-lesioned 5-HT receptor supersensitivity is additionally produced, and in fact 5-HT receptor antagonists attenuate enhanced DA D16-lesioned rats treated with haloperidol for one year, there is a 2-fold increase in numbers of VCMs (versus intact rats treated with haloperidol); and this high frequency of VCMs persists for more than 6 months after discontinuing haloperidol treatment. During this stage, 5-HT2 receptor antagonists, but not DA D1 receptor antagonists, attenuate the incidence of VCMs. This series of findings implicates the 5-HT neuronal phenotype in TD, and promotes 5-HT2 receptor antagonists, more specifically 5-HT2C receptor antagonists, as a rational treatment approach for TD in humans.

Malgré l’usage de médicaments antipsychotiques depuis plusieurs décennies, leur mécanisme d’action précis, autre que leur interaction avec les récepteurs dopaminergiques et sérotoninergiques, demeure peu connu. Nur77 (Nr4a1 ou NGFI-B) est un facteur de transcription de la famille des récepteurs nucléaires associé aux effets des antipsychotiques. Ceci étant dit, le mécanisme d’action de Nur77 est également peu connu. Afin de mieux comprendre les éléments impliqués avec les antipsychotiques et l’activité de Nur77, nous avons comparé les niveaux de transcrits dans le striatum suite à un traitement avec l’halopéridol chez des rats sauvages et déficients en Nur77 à l’aide de la technique de séquençage à haut débit (RNAseq) et d’une analyse bio-informatique. L’halopéridol et Nur77 ont modulé d’importants groupes de gènes associés avec la signalisation des récepteurs dopaminergiques et la synapse glutamatergique. L’analyse a révélé des modulations de gènes clés reliés à la signalisation des protéines G. Parmi les transcrits modulés significativement chez les rats traités avec halopéridol et ceux déficients en Nur77, la dual specificity phosphatase 5 (Dusp5) représente un nouveau candidat d’intérêt. En effet, nous avons confirmé que les niveaux d’ARNm et protéiques de Dusp5 dans le striatum sont associés aux mouvements involontaires anormaux (dyskinésie) dans un modèle de primates non-humains traités chroniquement avec halopéridol. Cette analyse transcriptomique a démontré des altérations rapides et importantes d’éléments impliqués dans la signalisation des protéines G par l’halopéridol, et a permis d’identifier, pour la première fois, une expression de Dusp5 dépendante de Nur77 en tant que nouvelle composante reliée avec la dyskinésie tardive. / Despite antipsychotic drugs being used for several decades, their precise mechanism of action remains elusive. Nur77 (Nr4a1 or NGFI-B) is a transcription factor of the nuclear receptor family associated with antipsychotic drug effects. However, the mechanism of action of Nur77 is also not well understood. To better understand the signaling components implicated with antipsychotic drug use and Nur77 activity, we compared striatal gene transcripts following haloperidol in wild-type and Nur77-deficient rats using Next Generation RNA Sequencing (RNAseq) and a bioinformatics analysis. Haloperidol and Nur77 modulated important subsets of striatal genes associated with dopamine receptor signaling and glutamate synapses. The analysis revealed modulations of key components of G protein signaling that are consistent with a rapid adaptation of striatal cells that may partially explain long-term haloperidol-induced dopamine D2 receptor upregulation. Amongst significantly modulated transcripts in rats treated with haloperidol and rats deficient in Nur77, dual specificity phosphatase 5 (Dusp5) represents a new and very interesting candidate. Indeed, we confirmed that striatal Dusp5 mRNA and protein levels were associated with abnormal involuntary movements (dyskinesia) in non-human primates chronically exposed to haloperidol. This transcriptomic analysis showed important haloperidol-induced G protein-coupled receptor signaling alterations that may support a regulatory role of Nur77 in dopamine D2 receptor signaling pathways and identified, for the first time, a putative Nur77-dependent expression of Dusp5 as a new signaling component for antipsychotic drug-induced tardive dyskinesia.

Les cellules épithéliales nasales humaines (CENH) sont des acteurs importants de la physiopathologie de la polypose naso-sinusienne (PNS), le plus souvent la PNS est primitive (étiologie inconnue), plus rarement, elle est secondaire à la mucoviscidose (PNS CF) ou la dyskinésie ciliaire primitive (PNS DCP). L'objectif de cette thèse est d'identifier des protéines différentiellement exprimées dans les PNS primitives et secondaires par approche protéomique puis de les caractériser par des techniques classiques. Dans cette étude, nous avons utilisé des cultures primaires (interface air/liquide) de CENH, dérivant de déchet per-opératoire (PNS) ou de brossages (muqueuse saine). Le marquage iTRAQ suivie d'une analyse par nano-LC-MALDI-TOF-TOF à en particulier montré : 1) une augmentation de six marqueurs du stress du réticulum endoplasmique (RE) dans la PNS primitive et la PNS CF, 2) une altération du métabolisme du glucose dans la PNS CF (sous-expression de 6 protéines dont la pyruvate kinase, enzyme clef de la glycolyse) et 3) une sous expression de 12 protéines des filaments acto-myosines dans la PNS DCP (dont 3 tropomyosines). Nous avons caractérisé le stress du RE dans la PNS primitive, montrant qu'il est induit par le biais d'une sensibilité des CENH à un stress oxydatif probablement d'origine mitochondrial et qu'il participe activement à l'inflammation (sécrétion d'IL-8 et de LTB4). Ces observations nous permettent de proposer que, dans la PNS primitive, il existe un cercle vicieux entre stress du RE, stress oxydatif et inflammation et que la sensibilité au stress oxydatif observée apparaît comme une nouvelle cible thérapeutique dans le traitement de la PNS. / Human nasal epithelial cells (HNEC) play an important role in nasal polyposis(NP). NP have generally an unknown etiology, less frequently, NP is secondary to cystic fibrosis (CF NP) or primary ciliary dyskinesia (PCD NP). The aim of this thesis is to identify differentially expressed proteins in NP, CF NP and PCD NP using proteomic approach then to characterize them by classical methodes. In this study, we used primary culture (air/liquid)of HNEC derived from NP patients (surgery waste) or healthy patients (brushing). The iTRAQ labeling folowing by nano-LC-MALDI-TOF-TOF analysis shown in particular :1)an increased expression of six endoplasmic reticulum (ER) stress markers in NP and CF NP, 2)an alteration of glucose metabolism (decreased expression of six proteins with in particular the pyruvate kinase, glycolysis key enzyme) and 3)an decreased expression of 12 acto-myosin filament proteins (in particular three tropomyosins). We caracterized the ER stress in NP showing that ER stress is activated by an oxydative stress susceptibility of NP HNEC probably of mitochondrial origin and that it directly participate to inflammation (IL-8 and LTB4 secretions). Altogether, our results underline a vicious circle that exists between oxidative stress, ER stress and inflammation.The oxydative stress susceptibility observed in NP may represent new therapeutic target in such a pathology.

Eukaryotic organisms rely on the coordinated beating of motile cilia for a multitude of fundamental reasons. In smaller organisms, such as Paramecium and the single cell alga Chlamydomonas reinhardtii, it is a matter of propulsion, to swim towards a higher concentration of nutrients or away from damaging environments. Larger organisms use instead the coordinated motion of cilia to push fluid along an epithelium: examples common to mammals are the circulation of cerebrospinal fluid in the brain, the transport of ovules in the fallopian tubes, and breaking the left/right symmetry in the embryo. Another notable example, and one that is central to this thesis, is mucociliary clearance in human airways: A carpet of motile cilia helps keeping the cell surface free from pathogens and foreign particles by constantly evacuating from lungs, bronchi, and trachea a barrier of mucus. The question of how motile cilia interact with one another to beat in a coordinated fashion is an open and pressing one, with immediate implications for the medical community. In order for the fluid propulsion to be effective, the motion of cilia needs to be phase-locked across significant distances, in the form of travelling waves (``metachronal waves''). It is still not known how this long-range coordination emerges from local rules, as there is no central node regulating the coordination among cilia. In the first part of this thesis I will focus on studying the coordination in carpets of cilia with a top-down approach, by proposing, implementing, and applying a new method of analysing microscope videos of ciliated epithelia. Chapter 1 provides the reader with an introduction on motile cilia and flagella, treating their structure and motion and reporting the different open questions currently tackled by the scientific community, with particular interest in the coordination mechanisms of cilia and the mucociliary clearance apparatus. Chapter 2 introduces Differential Dynamic Microscopy (DDM), a powerful and versatile image analysis tool that bridges the gap between spectroscopy and microscopy by allowing to perform scattering experiments on a microscope. The most interesting aspects of DDM for this work are that it can be applied to microscope videos where it is not possible to resolve individual objects in the field of view, and it requires no user input. These two characteristics make DDM a perfect candidate for analysing several hundred microscope videos of weakly scattering filaments such as cilia. In Chapter 3 I will present how it is possible to employ DDM to extract a wealth of often-overlooked information from videos of ciliated epithelia: DDM can successfully probe the ciliary beat frequency (CBF) in a sample, measure the direction of beating of the cilia, and detect metachronal waves and read their direction and wavelength. In vitro ciliated epithelia however often do not show perfect coordination or alignment among cilia. For the analysis of these samples, where the metachronal coordination might not be evident, we developed a new approach, called multiscale DDM (multiDDM), to measure a coordination length scale, a characteristic length of the system over which the coordination between cilia is lost. The new technique of multiDDM is employed in Chapter 4 to study how the coordination among cilia changes as a response to changes in the rheology of the mucous layer. In particular, we show that cilia beating under a thick, gel-like mucus layer show a larger coordination length scale, as if the mucus acted as an elastic raft effectively coupling cilia over long distances. This is corroborated by the coordination length scale being larger in samples from patients affected by Cystic Fibrosis than in healthy samples, and much shorter when the mucus layer is washed and cilia therefore beat in a near-Newtonian fluid. We then show how it is possible to employ multiDDM to measure the effectiveness of drugs in recovering, in CF samples, a coordination length scale typical of a healthy phenotype. In the second part I will focus instead on the single cilium scale, showing how we can attempt to link the beating pattern of cilia to numerical simulations studying synchronisation in a model system. In particular in Chapter 5 I will describe our approach to quantitatively describe the beating pattern of single cilia obtained from human airway cells of either healthy individuals or patients affected by Primary Ciliary Dyskinesia. Our description of the beating pattern, and the selection of a few meaningful, summary parameters, are then shown to be accurate enough to discriminate between different mutations within Primary Ciliary Dyskinesia. In Chapter 6 instead I report the results obtained by coarse-graining the ciliary beat pattern into a model system consisting of two ``rotors''. The rotors are simulated colloidal particles driven along closed trajectories while leaving their phase free. In my study, the trajectories followed by the rotors are analytical fits of experimental trajectories of the centre of drag of real cilia. The rotors, that are coupled only via hydrodynamics interactions, are seen to phase-lock, and the shape of the trajectory they are driven along is seen to influence the steady state of the system.

A doença de Parkinson (DP) é a segunda doença neurodegenerativa que mais atinge a população mundial. O desenvolvimento dos prejuízos motores decorrentes da doença está relacionado a sua fisiopatologia, que promove principalmente a neurodegeneração dos neurônios dopaminérgicos da substância negra pars compacta. Estudos sugerem o envolvimento de vias inflamatórias exacerbando a morte celular na fisiopatologia da DP. O fenômeno neuroinflamatório é caracterizado pela ativação de diversas células do sistema nervoso central, como neurônios, micróglia e astrócitos, além dos principais mediadores pró- inflamatórios, que são a enzima ciclooxigenase-2 (COX-2), o fator de necrose tumoral-alfa (TNF-?), a interleucina 1? (IL-1?) e a interleucina 6 (IL-6), entre outros. Estes fatores estão presentes em estruturas neuroanatômicas como o estriado e substância negra pars compacta de indivíduos com a DP. O tratamento crônico com L-DOPA, o precursor do neurotransmissor dopamina, inicialmente gera uma redução da manifestação dos sintomas motores na maioria dos pacientes. Porém, após certo tempo de tratamento, ocorre o surgimento de complicações motoras, como a discinesia induzida por L-DOPA (LID - LDOPA-induced dyskinesia). O desenvolvimento e a manifestação da LID também podem acompanhar uma resposta inflamatória anormal. Dados do grupo sugerem a enzima COX-2 e as células gliais como mediadores da LID. Estudos apontam que fármacos que reduzem a LID modulam a expressão de COX-2. Nosso objetivo, portanto, foi caracterizar a presença de fatores/mecanismos pró-inflamatórios no estriado lesionado de camundongos tratados com LDOPA. Nossos resultados serão apresentados em três capítulos. No primeiro capítulo, empregamos o modelo de camundongos hemiparkinsonianos (lesionados com 6- hidroxidopamina) e tratamos com L-DOPA por diferentes períodos de tempo (1, 7, 14 e 21 dias) para analisarmos o surgimento de fatores inflamatórios no estriado, como a enzima COX-2, o fator nuclear kappa-B (NF-?B) e a expressão e atividade dos astrócitos e micróglia. No segundo capítulo, demonstramos o potencial destas células gliais em produzir citocinas e/ou glutamato após estímulo com os principais neurotransmissores envolvidos com a LID, a DA (ou seu precursor L-DOPA) e glutamato. No terceiro capítulo, demonstramos o potencial terapêutico de drogas usadas na clínica - com propriedades anti-inflamatórias - de reduzirem a LID previamente estabelecida. Para tal, utilizamos o canabidiol (princípio ativo da Cannabis, usado no tratamento para epilepsia, entre outros) e o celecoxibe (inibidor específico da atividade enzimática da COX-2). Este estudo corrobora a existência de um processo inflamatório no estriado lesionado de camundongos parkinsonianos, exacerbado pelo tratamento com L-DOPA. A enzima COX-2 pode ter um papel fundamental no desenvolvimento da LID. Adicionalmente, este trabalho sugere que drogas utilizadas clinicamente com ação anti-inflamatória podem se tornar possíveis ferramentas terapêuticas para a redução desta desordem. Desta forma, relacionamos a produção de fatores inflamatórios e a ativação de células gliais à perpetuação de uma atividade pós-sináptica estriatal anormal que ocasionam a \"má plasticidade\" típica da LID. / Parkinson\'s disease (PD) is the second most common neurodegenerative disease in world population. The development of motor impairments related to this disease occurs due to its pathophysiology, which mainly promotes the neurodegeneration of the dopaminergic neurons in the substantia nigra pars compacta. Studies suggest the involvement of inflammatory pathways that exacerbate cell death in the pathophysiology of PD. The neuroinflammatory phenomenon is characterized by the activation of central nervous system cells, such as neurons, microglia and astrocytes, in addition to proinflammatory mediators that are elevated in patients with PD, such as the enzyme cyclooxygenase-2 (COX-2), tumor necrosis factoralpha (TNF-?), interleukin 1? (IL-1?) and interleukin-6 (IL-6), among others. These factors are present in neuroanatomic structures such as striatum and substantia nigra pars compacta. Chronic treatment with L-DOPA, the precursor of the neurotransmitter dopamine, initially generates a reduction in the manifestation of motor symptoms in the vast majority of patients, but after a certain time of treatment, motor complications begin to appear, such as L-DOPAinduced dyskinesia (LID). The development and manifestation of LID may also accompany an abnormal inflammatory response. Data from our group suggest the enzyme COX-2 as one of the mediators of LID. Studies also point out that drugs that reduce LID are able to modulate COX-2 expression. Our objective, therefore, was to characterize the presence of proinflammatory factors/mechanisms in the injured striatum of mice treated with L-DOPA. For this purpose, the present study will be divided into three chapters. In the first chapter, we used the hemiparkinsonian mice model (lesioned with 6-hydroxydopamine) treated with LDOPA for different time periods (1, 7, 14 and 21 days) to observe the appearance of inflammatory factors in the striatum, such as the COX-2 enzyme, nuclear factor kappa-B (NF- ?B) and the expression and activity of glial cells, represented by astrocytes and microglia. In the second chapter, we demonstrated the potential of glial cells to produce cytokines and/or glutamate after stimulation with the major neurotransmitters involved with LID, dopamine (or its precursor L-DOPA) and glutamate. Finally, in the third chapter, we demonstrate the therapeutic potential of drugs used in the clinic with anti-inflammatory properties to reduce previously established LID. For this, we used cannabidiol (the active constituent of Cannabis, used for the treatment of epilepsy, among others) and celecoxib (a specific COX-2 activity inhibitor). The present study corroborates the existence of an inflammatory process in the injured striatum of parkinsonian mice, exacerbated by treatment with L-DOPA. The COX-2 enzyme may play a key role in the development of LID. Additionally, this work suggests that drugs clinically used with anti-inflammatory action may become possible therapeutic tools for the reduction of this disorder. In this way, we relate the production of inflammatory factors and the activation of glial cells to the perpetuation of an abnormal striatal postsynaptic activity that causes the \"maladaptative plasticity\" typical of LID.

La maladie de Parkinson (MP) est une maladie neurodégénérative chronique qui apparait en moyenne à partir 55 ans. Sa cause reste inconnue mais son apparition et son développement sont corrélés avec la perte progressive des neurones dopaminergique de la substance noire qui innervent les ganglions de la base (GB). Jusqu'à ce jour le traitement le plus efficace est basé sur la compensation du déficit en dopamine (DA) par l'administration de son précurseur, la L-DOPA, qui est métabolisé en DA. Ce traitement améliore les symptômes moteurs de la maladie et donc la qualité de vie des patients. Néanmoins, après une certaine période des effets secondaires invalidants apparaissent, en particulier des fluctuations motrices et des mouvements anormaux involontaires appelés dyskinésies. De plus, ce traitement n'apporte pas de réponse à la progression de la dégénérescence et donc de la maladie. C'est pour ces raisons que la communauté scientifique est à la recherche d'une thérapie pharmacologique alternative à la L-DOPA, ou du moins visant à minimiser ses effets indésirables. Dans ce contexte, les récepteurs métabotropiques du glutamate, en particulier mGluR4, semblent constituer une cible privilégiée. En effet, mGluR4 est situé à des synapses des GB supposées hyperactives dans la MP, et son activation par des moyens pharmacologiques pourrait donc rétablir une activité normale grâce à son action inhibitrice sur la libération de neurotransmetteur. Nos résultats démontrent le bien-fondé de cette hypothèse sur le plan fonctionnel, en utilisant un nouvel agoniste allostérique spécifique de mGluR4, Lu AF21934. / Parkinson's disease (PD) is a progressive neurodegenerative disorder that appears around 55 years of age. The causes of PD remain unknown but its appearance and progression are correlated with the progressive loss of dopaminergic neurons of substantia nigra pars compacta innervating the basal ganglia (BG). Up to date, the most efficient treatment is based on restoring a normal level of dopamine (DA) in the brain by the administration of L-DOPA, a DA precursor that is metabolized to DA. However, at long term, L-DOPA treatment induces some side-effects, in particular the highly disabling L-DOPA-induced dyskinesia (LID). For this reason, the scientific community is searching for a pharmacological treatment alternative to L-DOPA and/or minimizing LID. In this context, metabotropic glutamate receptors, in particular mGluR4, are targets of interest. mGlu4 are localized at presynaptic terminals within BG circuitry that become hyperactive in PD. For this reason, mGluR4 has been considered a key strategic target for non-dopaminergic pharmacological treatments aimed at modulating these synapses, due to its ability to reduce neurotransmitter release. Herein we provide physiological and functional support to this hypothesis using Lu AF21934, a novel selective and brain-penetrant mGluR4 positive allosteric modulator (PAM). By in vitro electrophysiological recordings we demonstrate that Lu AF21934 inhibits corticostriatal synaptic transmission. In rats rendered parkinsonian, Lu AF21934 combined with sub-threshold doses of L-DOPA acted synergistically in alleviating akinesia in a dose-dependent manner and, notably, also reduced the incidence of LID.

Mon projet de thèse porte sur les altérations de la réponse dopaminergique dans la maladie de Parkinson (MP). Les troubles moteur de la MP sont améliorés par la L-Dopa (précurseur de la dopamine) et/ou les agonistes dopaminergiques. Cependant, ces traitements engendrent des effets secondaires moteurs (les dyskinésies) et non-moteurs. Ainsi, environ 15% des patients atteints de la MP sous agoniste dopaminergique vont présenter des addictions comportementales avec un syndrome de sevrage, et 3 à 4% des patients traités à la L-Dopa ou à l’apomorphine développent une prise compulsive de médicament. Ces complications motrices et non-motrices des thérapies dopaminergiques, font intervenir une dysfonction du réseau des ganglions de la base. Ce travail a exploré le lien entre l’accumulation de la protéine ΔFosB et les modifications des propriétés électriques des neurones impliqués dans l’expression des dyskinésies, en utilisant une technique d’inactivation sélective des neurones exprimant ΔFosB dans le striatum de rat et de singe. Mes travaux ont également évalué chez le singe, comment la L-Dopa modifiait les taux de monoamines pour engendrer les dyskinésies. Ceci m’a permis de montrer que les structures cognitives et limbiques sont elles aussi affectées et qu’elles pourraient être directement impliqués dans les dyskinésies. Sur cette base, j’ai étudié la physiopathologie des troubles du traitement de la récompense et démontré que la L-Dopa, le traitement de référence de la MP, peut acquérir des propriétés récompensantes proches de celles de la cocaïne dans un modèle rat de la MP par surexpression de gène codant pour l’α-synucléine mutée. J’ai également utilisé des procédures d’auto-administration intraveineuse chez le rat pour montrer que le Pramipexole, un agoniste dopaminergique couramment utilisé dans le traitement de la MP, possédait des propriétés renforçantes. Ceci m’a permis de souligner que des susceptibilités individuelles sous-tendraient le développement de ces addictions comportementales. Ces découvertes ont ensuite été complétées par des expériences montrant que les altérations liées à la MP modifiaient le trait d’impulsivité des rats et que les traitements dopaminergiques pouvaient empirer ces changements. / My PhD focused on the alterations of the dopaminergic response in Parkinson’s disease (PD). Motor impairments in PD are reduced by the dopamine precursor L-Dopa and/or dopamine agonists. However, these medications elicit motor (dyskinesia) and non-motor side-effects. Up to 15% of PD patients under dopamine agonists experience behavioral addictions and withdrawal syndrome, and 3-4% of patients treated with L-Dopa or apomorphine exhibit compulsive medication intake. Both motor and non-motor complications of dopaminergic therapies involve dysfunctions in the basal ganglia network. I explored the link between deltaFosB protein accumulation and the cellular electrical properties that trigger dyskinesia by using a cell-type specific inactivation of FosB expressing neurons of the striatum in rats and monkeys. I have also investigated in monkeys how L-Dopa modifies monoaminergic functions to mediate dyskinesia and demonstrated that limbic/cognitive structures are identically affected providing a basis for a non-motor component involved in motor side effects in PD. From this, I studied the pathophysiology of addiction-like disorders by revealing that L-Dopa, the most widely-used treatment for PD, can acquire rewarding properties similar to cocaine in a viral-mediated rat model of PD. I also used self-administration procedures in rats to demonstrate the rewarding properties of Pramipexole, a dopamine agonist commonly use in the treatment of PD, and identified individual susceptibilities in the development of addiction-like disorders. These findings were followed by additional work showing that PD alterations modify the impulsivity trait of rats and that medication might worsen these changes.

La maladie de Parkinson (MP) est caractérisée par une dégénérescence progressive et irréversible des neurones dopaminergiques (DA) de la substance noire. Lorsque la perte DA atteint 60 à 80%, les patients vont développer des symptômes. Les traitements DA permettent de contrecarrer l'expression de ces symptômes mais induisent également à long terme l'apparition de complications invalidantes. De plus les patients développent également des symptômes non- moteurs pouvant émerger avant, pendant ou après l'apparition des symptômes moteurs. Parallèlement à la dégénérescence DA, les patients parkinsoniens présentent des altérations du système sérotoninergique (5-HT) qui ont été mises en évidence en post-mortem et plus récemment par imagerie par tomographie à émission de positons (TEP). Des corrélations ont également été démontrées entre l'altération du système 5-HT et la sévérité de certains symptômes parkinsoniens. Cependant, à ce jour, aucune étude n'a mis en évidence de lien causal direct entre l'altération 5-HT et l'expression des symptômes parkinsoniens. Il était donc crucial de clarifier le rôle exact de la 5-HT dans le développement des symptômes parkinsoniens ainsi que dans la réponse aux traitements dopaminergiques. Dans ce contexte, nous avons développé un nouveau modèle de la MP. Ce modèle nous a permis d'étudier l'impact de la lésion 5-HT sur la symptomatologie parkinsonienne. Ce travail a permis de démontrer l'implication du système sérotoninergique dans l'expression de la rigidité parkinsonienne. Par ailleurs, ce travail a également permis de démontrer le rôle causal des fibres 5-HT dans le développement de complications induites par un traitement chronique à la L- DOPA / Parkinson's disease (PD) is characterized by a progressive and irreversible degeneration of dopaminergic (DA) neurons localized in the substantia nigra, leading to the loss of dopamine within the target structures (mainly the striatum). When the DA loss reaches 60 to 80%, PD patients develop motor symptoms (rigidity, tremor, akinesia/bradykinesia). DA treatments allow counteracting symptoms expression but also induce after a certain time the appearance of disabling complications. Moreover, patients also develop non-motor symptoms that can emerge before, during or after the appearance of motor symptoms. ln addition to DA degeneration, PD patients present serotoninergic (5-HT) alteration evidenced in post-mortem and more recently by position emission tomography (PET) imaging. Correlations have been shown between the 5-HT alteration and the severity of some motor and non-motor symptoms as well as L-DOPA-induced dyskinesia. However, to date, none study evidenced a direct causal link between the 5-HT alteration and the expression of parkinsonian symptoms. lt was crucial to clarify the exact role of 5-HT in the development of parkinsonian symptoms. ln this context, we have developed a new model of PD. This model has allowed studying the impact of the 5-HT lesion on the parkinsonian symptomatology. We have evidenced the involvement of the 5-HT system in the expression of parkinsonian rigidity. Moreover, we have demonstrated the causal role of the 5-HT fibers in the development of complications induced by the L-DOPA treatment

A doença de Parkinson (DP) é a segunda doença neurodegenerativa que mais atinge a população mundial. O desenvolvimento dos prejuízos motores decorrentes da doença está relacionado a sua fisiopatologia, que promove principalmente a neurodegeneração dos neurônios dopaminérgicos da substância negra pars compacta. Estudos sugerem o envolvimento de vias inflamatórias exacerbando a morte celular na fisiopatologia da DP. O fenômeno neuroinflamatório é caracterizado pela ativação de diversas células do sistema nervoso central, como neurônios, micróglia e astrócitos, além dos principais mediadores pró- inflamatórios, que são a enzima ciclooxigenase-2 (COX-2), o fator de necrose tumoral-alfa (TNF-?), a interleucina 1? (IL-1?) e a interleucina 6 (IL-6), entre outros. Estes fatores estão presentes em estruturas neuroanatômicas como o estriado e substância negra pars compacta de indivíduos com a DP. O tratamento crônico com L-DOPA, o precursor do neurotransmissor dopamina, inicialmente gera uma redução da manifestação dos sintomas motores na maioria dos pacientes. Porém, após certo tempo de tratamento, ocorre o surgimento de complicações motoras, como a discinesia induzida por L-DOPA (LID - LDOPA-induced dyskinesia). O desenvolvimento e a manifestação da LID também podem acompanhar uma resposta inflamatória anormal. Dados do grupo sugerem a enzima COX-2 e as células gliais como mediadores da LID. Estudos apontam que fármacos que reduzem a LID modulam a expressão de COX-2. Nosso objetivo, portanto, foi caracterizar a presença de fatores/mecanismos pró-inflamatórios no estriado lesionado de camundongos tratados com LDOPA. Nossos resultados serão apresentados em três capítulos. No primeiro capítulo, empregamos o modelo de camundongos hemiparkinsonianos (lesionados com 6- hidroxidopamina) e tratamos com L-DOPA por diferentes períodos de tempo (1, 7, 14 e 21 dias) para analisarmos o surgimento de fatores inflamatórios no estriado, como a enzima COX-2, o fator nuclear kappa-B (NF-?B) e a expressão e atividade dos astrócitos e micróglia. No segundo capítulo, demonstramos o potencial destas células gliais em produzir citocinas e/ou glutamato após estímulo com os principais neurotransmissores envolvidos com a LID, a DA (ou seu precursor L-DOPA) e glutamato. No terceiro capítulo, demonstramos o potencial terapêutico de drogas usadas na clínica - com propriedades anti-inflamatórias - de reduzirem a LID previamente estabelecida. Para tal, utilizamos o canabidiol (princípio ativo da Cannabis, usado no tratamento para epilepsia, entre outros) e o celecoxibe (inibidor específico da atividade enzimática da COX-2). Este estudo corrobora a existência de um processo inflamatório no estriado lesionado de camundongos parkinsonianos, exacerbado pelo tratamento com L-DOPA. A enzima COX-2 pode ter um papel fundamental no desenvolvimento da LID. Adicionalmente, este trabalho sugere que drogas utilizadas clinicamente com ação anti-inflamatória podem se tornar possíveis ferramentas terapêuticas para a redução desta desordem. Desta forma, relacionamos a produção de fatores inflamatórios e a ativação de células gliais à perpetuação de uma atividade pós-sináptica estriatal anormal que ocasionam a \"má plasticidade\" típica da LID. / Parkinson\'s disease (PD) is the second most common neurodegenerative disease in world population. The development of motor impairments related to this disease occurs due to its pathophysiology, which mainly promotes the neurodegeneration of the dopaminergic neurons in the substantia nigra pars compacta. Studies suggest the involvement of inflammatory pathways that exacerbate cell death in the pathophysiology of PD. The neuroinflammatory phenomenon is characterized by the activation of central nervous system cells, such as neurons, microglia and astrocytes, in addition to proinflammatory mediators that are elevated in patients with PD, such as the enzyme cyclooxygenase-2 (COX-2), tumor necrosis factoralpha (TNF-?), interleukin 1? (IL-1?) and interleukin-6 (IL-6), among others. These factors are present in neuroanatomic structures such as striatum and substantia nigra pars compacta. Chronic treatment with L-DOPA, the precursor of the neurotransmitter dopamine, initially generates a reduction in the manifestation of motor symptoms in the vast majority of patients, but after a certain time of treatment, motor complications begin to appear, such as L-DOPAinduced dyskinesia (LID). The development and manifestation of LID may also accompany an abnormal inflammatory response. Data from our group suggest the enzyme COX-2 as one of the mediators of LID. Studies also point out that drugs that reduce LID are able to modulate COX-2 expression. Our objective, therefore, was to characterize the presence of proinflammatory factors/mechanisms in the injured striatum of mice treated with L-DOPA. For this purpose, the present study will be divided into three chapters. In the first chapter, we used the hemiparkinsonian mice model (lesioned with 6-hydroxydopamine) treated with LDOPA for different time periods (1, 7, 14 and 21 days) to observe the appearance of inflammatory factors in the striatum, such as the COX-2 enzyme, nuclear factor kappa-B (NF- ?B) and the expression and activity of glial cells, represented by astrocytes and microglia. In the second chapter, we demonstrated the potential of glial cells to produce cytokines and/or glutamate after stimulation with the major neurotransmitters involved with LID, dopamine (or its precursor L-DOPA) and glutamate. Finally, in the third chapter, we demonstrate the therapeutic potential of drugs used in the clinic with anti-inflammatory properties to reduce previously established LID. For this, we used cannabidiol (the active constituent of Cannabis, used for the treatment of epilepsy, among others) and celecoxib (a specific COX-2 activity inhibitor). The present study corroborates the existence of an inflammatory process in the injured striatum of parkinsonian mice, exacerbated by treatment with L-DOPA. The COX-2 enzyme may play a key role in the development of LID. Additionally, this work suggests that drugs clinically used with anti-inflammatory action may become possible therapeutic tools for the reduction of this disorder. In this way, we relate the production of inflammatory factors and the activation of glial cells to the perpetuation of an abnormal striatal postsynaptic activity that causes the \"maladaptative plasticity\" typical of LID.