Zinc finger protein regulator of apoptosis and cell cycle arrest 1 (Zac1) est un facteur de transcription suppresseur de tumeurs capable, à travers des voies différentes et indépendantes, dinduire lapoptose ou larrêt du cycle cellulaire. Malgré ses implications potentielles dans le développement embryonnaire et certaines maladies telles que le cancer et le diabète néonatal, les mécanismes régulant son expression physiologique, ainsi que sa fonction biologique exacte restent méconnus. Les deux principaux objectifs de notre travail consistaient, dune part, à définir la nature des stimuli capables de moduler lexpression endogène de la protéine Zac1 et, dautre part, à étudier la fonction de Zac1. Nous avons tout dabord montré que la protéine Zac1 nétait pas exprimée dans les organes murins où lon détecte son ARN messager. Nous navons cependant pas pu mettre en évidence de mécanisme de dégradation de la protéine Zac1. Malgré ses similitudes de fonction avec le suppresseur de tumeurs p53, Zac1 nétait également pas exprimée après traitement avec des inducteurs de p53 tels que des inducteurs de dommages à lADN. Après avoir testé sans succès de nombreux stimuli pro-inflammatoires susceptibles dinduire lexpression de Zac1, nous avons finalement découvert que le variant de transcrit Zac1b était exprimé dans des fibroblastes embryonnaires murins (MEFs) traités à lacide polyriboinosinique polyribocytidylique poly(I:C), un double brin dARN synthétique. Cette régulation sest avérée être dépendante de la voie du Toll-Like Receptor 3 (TLR3) et de lInterferon Regulatory Factor 3 (IRF3), et indépendante des interférons (IFNs) de type I. Le TLR3 et IRF3 étant des activateurs centraux de limmunité antivirale, nous avons tenté de déterminer si Zac1 pourrait être impliqué dans la réponse antivirale. En rapport avec cette hypothèse, nous avons observé que Zac1b était exprimé dans des MEFs infectées avec le virus de lEncéphalomyocardite (EMCV). Nous avons également constaté que les MEFs déficientes pour Zac1 étaient moins sensibles à la mort cellulaire induite par lEMCV que les MEFs sauvages. Cependant, linactivation du gène Zac1 navait pas deffet sur la survie des souris infectées à lEMCV. En conclusion, ce travail décrit, pour la première fois, une régulation transcriptionnelle de Zac1b induite par des ARN double brin synthétiques et des virus à ARN, mais dont la signification fonctionnelle reste à découvrir. De plus, il montre que les stimuli capables dinduire p53 ninduisent pas lexpression de la protéine Zac1 suggérant que la protéine Zac1 est régulée différemment de p53.

Activation of the immune system in gestating mothers has been identified as an important environmental risk factor for neuropsychiatric disorders. Maternal immune activation (MIA) animal models have been used to explore how the maternal immune system may cause expression of pathophysiology in offspring. Protein tyrosine phosphatase (PTP1B) is recruited during inflammation and its regulatory proteins are modulated in MIA. Disrupted regulation of PTP1B has been linked to mental disorders such as Rett Syndrome and anxiety. We asked if ablating neuronal PTP1B could protect from the expression of some neuropsychiatric phenotypes that appear in MIA models. In our MIA model induced with poly I:C injection at gestational day 9.5, we observed increased locomotion and sensorimotor gating and reduced anxiety in 3-month-old male offspring while females showed decreased sensorimotor gating. These effects were not replicated in PTP1B KO mice indicating a role of PTP1B in affecting locomotion and anxiety level in MIA. This model promotes a more balanced understanding of MIA and introduces PTP1B as a player in MIA-induced behaviour changes.

Interleukin-10 (IL-10) is a pleiotropic cytokine which limits inflammatory responses by balancing the hosts immune response against infection. Mammalian Toll-like receptors (TLRs) are pattern recognition receptors that recognize specific molecular pattens on microbial pathogens and activate intracellular signaling via the transcription factors NF-B and IRF-3. In this study we evaluate the contribution of the TLR ligands Poly I:C, Pam3CSK4, LPS and LTA to IL-10 receptor dysfunction in murine peritoneal macrophages (PM). We examine how these ligands are able to alter IL-10 mediated STAT3 phosphorylation and CCR5 gene expression in PM. The ability of Poly I:C and Pam3CSK4 to alter the immunosuppressive activity of IL-10 in C2-ceramide stimulated PM is also examined. The results of our study indicate a delayed inhibition of IL-10 mediated activation of STAT3 by LPS, LTA, Poly I:C and Pam3CSK4. The CCR5 gene expression experiments demonstrate that LPS was able to down-regulate IL-10 induced CCR5 mRNA expression in PM.

The developmental stress hypothesis predicts that an aversive condition, such as decreased food intake, predation, and social isolation, in the early developmental stage could have long term effects on behaviors and brain development of an animal. In nature, bird nestlings are susceptible to various factors, such as malnutrition, infections, and parasites. Effects of early life stress on adulthood have been extensively studied with some stressors including malnutrition. However, immune challenges as an early life stressor and their long-term programming effects on adult behaviors are yet to be studied in detail. The goal of the current study was to investigate changes in growth rate, personality, mate selection behaviors and brain development in zebra finch nestlings after injection with a viral infection mimicking agent, Polyinosinic: polycytidylic acid (Poly I:C). By using Poly I:C, it was possible to isolate long-term effects to the immune response of the bird. After Poly I:C injection on post-hatch day (PD) 14, morphological measures were conducted to detect changes in body growth rate. When birds became sexually mature (> ~PD 200), behaviors of birds were observed in different conditions to detect changes associated with the personality traits of animals. In mate choice trials, both attractiveness of males and mate selection behaviors of males and females were investigated. Finally, the development and neuronal activity of specific brain nuclei involved in courtship (i.e., HVC and RA) and social/sexual behaviors (nucleus taeniae of the amygdala, TnA) were investigated. The results showed that nestlings’ growth rate was not affected. However, Poly I:C injection had some effects on certain, but not all, personality traits observed in the study. Such effects were found only in female zebra finches, suggesting that there was a limited sex-specific influence of an early life immune challenge on personalities of adults. The results also showed that Control females tended to choose untreated males over Poly I:C injected males in mate choice trials. Finally, Poly I:C injection negatively affected the overall development of targeted brain nuclei. In addition, neuronal activity in TnA was higher in Poly I:C injected birds. Results of the present study suggest that one time injection with Poly I:C early in the life causes long term effects on adulthood. These findings are further discussed regarding their relevance to the developmental stress hypothesis.

京都大学 / 新制・課程博士 / 博士(生命科学) / 甲第24052号 / 生博第478号 / 新制||生||63(附属図書館) / 京都大学大学院生命科学研究科高次生命科学専攻 / (主査)教授 朝長 啓造, 教授 野田 岳志, 教授 今吉 格 / 学位規則第4条第1項該当 / Doctor of Philosophy in Life Sciences / Kyoto University / DFAM

Les études épidémiologiques ont démontré un risque accru d’autisme chez les enfants nés d’une mère hospitalisée pour infection au cours de la grossesse. L’imitation d’une infection virale dans le but de déclencher une Activation Immunitaire Maternelle (MIA) a été réalisé avec succès dans des modèles animaux. Ceci a démontré qu’une MIA conduit à des altérations physiologiques et comportementales sur le long terme. Notre but consistait à étudier la présence de séquelles néonatales chez des souris nées de mère MIA. Nous avons observé que la MIA altère l’activité et la morphologie des neurones dès la naissance, et que ces modifications restaient présentes dans les animaux âgés de deux semaines. La MIA subie au cours de la grossesse altère donc les neurones dès la naissance. / Epidemiological studies have shown an increased risk for autism in children born from mothers hospitalized for infection during pregnancy. Mimicking a maternal infection during pregnancy to trigger a Maternal Immune Activation (MIA) has been successfully achieved in animal models, showing that it leads to long term physiological and behavioural alterations. Our goal was to investigate neonatal sequels in MIA mice offspring. We found that already at birth MIA alters neuronal activity and morphology, and these changes were still present in two-week-old animals. Consequently, MIA during pregnancy alters neurons already at birth.

Les troubles du spectre autistique (TSA) sont une pathologie psychiatrique neurodéveloppementale dont les premiers signes apparaissent dès l’enfance et persistent tout au long de la vie. Leur étiologie complexe reste encore très mal connue et les données actuelles n’ont pas permis à ce jour de développer des traitements curatifs.L’objectif de cette thèse était d’identifier les réseaux neuronaux impliqués dans les symptômes moteurs afin de proposer une nouvelle piste diagnostique et d’ouvrir de nouvelles voies thérapeutiques ciblant ces réseaux. Nous avons donc exploré par une approche neuroanatomique, les régions contribuant au contrôle moteur : le cervelet, la substance noire pars compacta, le striatum et le cortex moteur. Cette étude a été réalisée sur deux modèles murins environnementaux liés à une exposition in utero soit à une molécule pharmacologique utilisée comme traitement antiépileptique : l’acide valproïque, soit à un agent pathogène mimant une infection virale : l’acide polyinosinique:polycytidylique. Nos résultats indiquent des pertes neuronales restrictives dans le cervelet et dans le cortex moteur qui dépendent du sexe des animaux et du modèle. Ils reflètent alors l’hétérogénéité retrouvée chez les patients selon les syndromes ainsi que les différences entre les hommes et les femmes. Nous avons également montré que cette perte neuronale pouvait être liée à la fois aux déficits moteurs et sociaux. Ainsi, ces régions cérébrales pourraient servir de cible thérapeutique pour pallier à ces symptômes des TSA. / Autism spectrum disorders (ASD) are psychiatric and neurodevelopmental disabilities that begins early in childhood and lasts throughout a person's life. The complex etiology is currently unknown and does not allow to develop new therapeutical strategies. The aim of this thesis was to identify the neuronal network involved in motor symptoms and propose new diagnostic tools and new therapeutical approaches focusing this linkage. We anatomically investigated the different regions responsible for motor control: the cerebellum, the substantia nigra pars compacta, the striatum and the motor cortex. This study has been performed using two environmental mouse models, prenatally exposed to either an anticonvulsant drug: the valproic acid, either an immunostimulant mimicking a viral infection: the polyinosinic:polycytidylic acid.Our results have indicated restricted neuronal losses in the cerebellum and in the motor cortex, which were model- and sex-dependent. These data also point out the heterogeneity found according to the different syndromes and the sex ratio in patients. Furthermore, we have also shown that the neuronal loss could be associated to as well the motor and the social deficits. Interestingly, these brain regions could be used as therapeutical target to reverse both ASD symptoms.

Depuis 2008, des épisodes de surmortalité massive d’origine multifactorielle, affectent mondialement les élevages de juvéniles d’huître creuse Crassostrea gigas dont le virus de type herpès, l’OsHV-1, peut être considéré comme un des agents pathogènes majeurs. L’immunité des huîtres, repose sur un système immunitaire inné et a longtemps été considéré comme peu spécifique et dépourvu de mémoire. Cependant, cette vision a été remise en question via des études ayant démontré l’existence d’une réponse immunitaire spécifique et mémoire chez des invertébrés. Dans le cadre de cette thèse, l’objectif était de caractériser le priming immunitaire antiviral ainsi que ses mécanismes chez l’huître face au virus OsHV-1. En stimulant les huîtres avec un agent mimétique viral, le poly(I:C), nos travaux ont montré que cette molécule protégeait spécifiquement contre l’OsHV-1 en milieu contrôlé et en milieu naturel sur le long terme, en améliorant le taux de survie des huîtres de près de 100%, mais pas d’infections bactériennes. Une approche RNA-seq nous a permis d’identifier différentes voies de signalisations immunitaires antivirales régulées suite à la stimulation par le poly(I:C). Les profils de régulation sont majoritairement maintenus dans le temps (au moins 10 jours), ce qui pourrait expliquer la protection observée. L’ensemble de ces résultats montre l’existence d’un phénomène de priming immunitaire antiviral efficace chez un Lophotrochozoaire et apporte une contribution à la compréhension des mécanismes moléculaires sous-jacents à ce phénomène. Ces travaux ont permis d’apporter des pistes de sortie de crise pour la filière ostréicole jusqu’alors inexplorées. / Since 2008, mass mortality events of multifactorial origin have affected the Pacific oyster Crassostrea gigas farms worldwide, in which a herpesvirus, the OsHV-1, can be considered as one of the major pathogens. The immunity of oysters, as for all invertebrates, is based on an innate immune system that has long been considered to be scarcely specific and to lack memory. However, in recent years this simplistic view has been questioned through studies that have demonstrated the existence of a specific immune response and memory. However, knowledge about the mechanisms underlying these phenomena still remains extremely fragmentary. The aim of this thesis was to characterize the antiviral immune priming and its mechanisms in the oyster against OsHV-1. By stimulating oysters with a viral mimic, poly(I:C), we have shown that this molecule specifically protects against OsHV-1 in controlled environment and in natural environment, protecting oysters from mass mortality events on the long term (min. 5 months) by improving oyster survival by almost 100% but does not protect against bacterial infection. A RNA-seq approach carried out during this thesis allowed us to identify different antiviral immune pathways regulated following the stimulation by poly(I:C). The regulation profiles are mostly maintained over time (at least 10 days), which could explain the observed protection. All these results show the existence of an effective antiviral immune priming phenomenon in a Lophotrochozoan and contribute to the understanding of the molecular mechanisms underlying this phenomenon. This work opens new perspectives hitherto unexplored to support oyster farming against this crisis.

Antipsychotic medications remain the first line of treatment for individuals diagnosed with schizophrenia (SCZ). However, antipsychotic treatment is often not compliant due to dysregulation of both the central (CNS) and autonomic (ANS) nervous systems, resulting in debilitating dose-dependent side effects. Recent work suggests a new approach for treatment of SCZ that could potentially lower treatment doses and reduce side effects. Increased neuroinflammation has been shown in patients diagnosed with SCZ, particularly within the prefrontal cortex (PFC) and hippocampal (HPC) regions of the brain. Tumor necrosis factor-alpha (TNFa) is one of the key pro-inflammatory cytokines observed to be secreted during the inflammatory response. When TNFa is chronically secreted, resident CNS microglia become pro-inflammatory and toxic to the local environment. Microglial activation alongside of dopamine dysregulation thereby results in both the behavioral and neuroinflammatory aspects of SCZ. In this study, we hypothesized dietary administration of two different novel TNFamodulators (PD2024 – Experiment 1 and PD340 – Experiment 2) developed by our collaborators from P2D Bioscience, Inc. (Cincinnati, OH) would alleviate auditory sensorimotor gating deficits and reduce microglial cell activation caused by neonatal polyinosinic:polycytidylic acid (Poly I:C) treatment in rats, which is a validated rodent model of SCZ. Four groups (Experiment 1: Poly IC/PD2024, Poly IC/Control, Saline/PD2024, Saline/Control and Experiment 2: Poly IC/PD340, Poly IC/Control, Saline/PD340, Saline/Control) were intraperitoneally administered either Poly I:C (2 mg/kg) or saline (0.9% NaCl) from postnatal days 5-7. From P30-67, animals were placed on the experimental diet containing either low (10 mg/kg) or high (30 mg/kg) doses of either PD2024 or PD340, whereas the control animals remained on a normal diet. Prepulse inhibition (PPI) was used to test for auditory sensorimotor gating (behavioral abnormalities) in both adolescence (P44-46) and in adulthood (P60-66). At P67, immunohistochemistry (IHC) and confocal microscopy were used to evaluate and examine microglial cell activation using the Iba1-GFP antibody (neuroinflammatory abnormalities) in the PFC and HPC. Results revealed auditory sensorimotor gating deficits in Poly IC/Controls were alleviated in both adolescence and adulthood with either PD2024 or PD340. It was also found that both TNFa modulators significantly reduced microglial activation in the HPC, but not the PFC. The data supports our hypothesis that dietary administration of PD2024 or PD340 alleviates behavioral deficits and decreases neuroinflammation generated from the Poly I:C rodent model of SCZ. Therefore, an approach with a TNFa modulator alongside of current antipsychotic medications could treat both the behavioral and neuroinflammatory aspects of SCZ.

The aim of thesis was to study murine melanoma B16- F10 therapy based on the use of TLR agonists combinedwith activation of phagocytosis. Mechanisms of this therapy were studied on the bases of analysis of tumor infiltrating immune cells and evaluationof thein effect on tumor cells.