Les lésions spinales cervicales sont au premier rang de l'épidémiologie des lésions spinales. Ce type de lésion porte atteinte aux commandes motrices bulbo-spinales respiratoires et entraîne des insuffisances respiratoires mettant en jeu le pronostic vital du patient. L'étude de la récupération spontanée de la fonction respiratoire et le développement de stratégies réparatrices constituent un enjeu majeur. Les stratégies thérapeutiques par greffe de cellules engainantes olfactives sont les plus prometteuses. Nous exposons l'effet de la transplantation de cellules gliales olfactives d'origine nasale au niveau spinal dans le cadre d'une hémi-contusion spinale cervicale chez le rat adulte et de la récupération de la fonction respiratoire. Nous montrons également, pour la première fois, qu'une lésion spinale a un impact sur les foyers de neurogenèse du cerveau et qu'un phénomène de neuroprotection se met en place dans la medulla du tronc cérébral suite à une lésion spinale. Nos travaux se replaçent dans une thématique clinique très actuelle, riche en publications. Il est impératif de prendre en compte les conséquences sus-lésionnelles d'une lésion spinale notamment pour la médecine régénératrice. / Cervical spinal cord injuries are the most frequent type of spinal cord injury. It interrupts motor bulbospinal respiratory pathway inducing respiratory deficits bringing into play the vital diagnostic of patients. The study of spontaneous recovery of respiratory function and the development of reparing strategies are a major issue. Therapeutic strategies by olfactory enseathing cells are the most promising. We show the effect of nasal olfactory enseathing cells transplantation at the spinal level considering a cervical spinal cord hemicontusion in adult rat and the recovery of respiratory function. We also demonstrate, for the first time, that spinal cord injury has an impact on adult brain neurogenesis niches and that a neuroprotective phenomenon appears after spinal cord injury in the medulla of the brainstem. Our results concerns an actual clinical research theme, well-referenced in publications. It is of high importance to consider supralesional consequences of spinal cord injury, especially for the regenerative medicine

Le système constitué de la zone sous ventriculaire (ZSV) et du bulbe olfactif (BO) est l’une des deux régions cérébrales capables à l’âge adulte de produire de nouveaux neurones. La mise en évidence de cette neurogénèse adulte bulbaire a suscité un grand nombre d’interrogations quant à son rôle fonctionnel. Cependant les études réalisées dans ce domaine sont rares et contradictoires. L’objectif de cette thèse a été d’étudier l’impact de différentes expériences olfactives sur la neurogénèse afin de mieux comprendre son rôle fonctionnel. Nous avons choisi pour cela deux approches : d’une part l’étude de l’implication des néoneurones bulbaires lors de deux tâches d’apprentissage olfactif mettant en œuvre des odeurs neutres ; et d’autre part l’étude du rôle de ces néoneurones dans une situation de vie où l’olfaction joue un rôle primordial et où des variations de neurogénèse ont été rapportées: la maternité. Dans un premier temps, nous avons mis en évidence grâce à une stratégie d’anatomie fonctionnelle que les néoneurones de 5 semaines étaient recrutés lors d’un apprentissage de discrimination olfactive, mais pas lors de la restitution de cette information. Dans un deuxième temps, nous avons mis en évidence que la maternité améliorait les performances olfactives, et que cette amélioration était abolie par un stress gestationnel. Cependant, nous n’avons pas pu mettre en relation ces modifications de performances olfactives liées à la maternité et au stress avec des variations de neurogénèse. Nos travaux supportent l’hypothèse selon laquelle les néoneurones bulbaires sont impliqués dans la discrimination olfactive et mettent en évidence pour la première fois un impact de la maternité, qu’elle soit normale ou pathologique, sur les performances olfactives des mères. / In the mammalian brain, the subventricular zone (ZSV) and olfactory bulb (BO) system is a region where new neurons are continuously added throughout adulthood. While the functional consequences of continuous hippocampal neurogenesis have been extensively studied, the role of olfactory adult-born neurons remains more elusive. In particular, the involvement of these newborn neurons in odor discrimination and long-term odor memory is still a matter of debate. To address this question, we used two approaches. In the first one, we studied the recruitment of granular olfactory newborn neurons in two different tasks of olfactory learning with neutral odors. In the second one we studied the role of olfactory newborn neurons in a life situation where olfaction is crucial and where an increase in olfactory neurogenesis was reported, i.e. motherhood. In the first study, we found that odor discrimination learning recruited newborn neurons preferentially over preexisting ones, while odor memory restitution did not specifically activate newborn cells. Results of our second study indicate that motherhood improves olfactory memory and that this enhancement is abolished by a gestational stress. However, in our experimental conditions, we could not relate variations in neurogenesis with the modifications of olfactory performances linked to motherhood or stress. In conclusion our work brings new data in support of a functional role for newborn neurons in olfactory discrimination and shows for the first time an impact of motherhood, whether normal or pathological, on the olfactory performances of mothers.

No description available.

Scratch2 (Scrt2) é um fator de transcrição (FT) expresso em células neurais recém-pós-mitóticas. O mecanismo de regulação de sua transcrição permanece desconhecido. Nós buscamos por potenciais elementos cis-regulatórios (CR) e sítios de ligação para FT na região genômica de Scrt2. Nós testamos o efeito in vivo da região CR intrônica através de eletroporação em embrião de galinha. Esta CR intrônica levou à expressão de eGFP tubo neural, mas não gerou um padrão semelhante ao Scrt2 endógeno. Estes dados sugerem que esta região CR pode contribuir com o controle da expressão de Scrt2, mas requer regiões regulatórias adicionais. Nós também verificamos o papel de mAsh1, cPax6, cNgn2 e Brn na regulação da expressão de Scrt2 através da superexpressão destes no tubo neural embrionário. As análises foram realizadas por qPCR e hibridação in situ. A superexpressão de mAsh1 e cNgn2 levou a um leve aumento na expressão de cScrt2 visto através da hibridação in situ. Já a superexpressão de cPax6 e mBrn-Eng reduziu os níveis de cScrt2, com Brn apresentando efeitos mais severos. / Scratch2 (Scrt2) is a transcription factor expressed in early post-mitotic neural cells. The mechanisms that control its transcription remain unknown. We searched for potential cis-regulatory elements and putative transcription factors binding sites in the genomic region of cScrt2. Then, we tested the function of a candidate cis-regulatory intronic region through electroporation in chick embryos. This fragment drove eGFP expression in the neural tube of chick embryo, but its expression did not resemble the cScrt2 endogenous pattern. Thus, this cis-regulatory region likely requires the presence of other regulatory regions. We also evaluated the role of mAsh1, cPax6, cNgn2 e Brn in regulating cScrt2 expression through overexpression of these factors in chick neural tubes and subsequent qPCR and in situ hybridization. Overexpression of mAsh1 and cNgn2 increased slightly cScrt2 expression level as seen by in situ hybridization. Overexpression of cPax6 and mBrn-Eng, reduced cScrt2 levels, with more severe effects with Brn.

No final do século 19, o neurônio foi descrito como a unidade funcional básica do sistema nervoso e sua formação era considerada inexistente na fase adulta, explicando a ausência de recuperação significativa em doenças neurológicas. Evidências de geração de neurônios em mamíferos adultos surgiram na década de 1960 e foram confirmadas três décadas depois. Atualmente, predomina a visão de que mamíferos adultos possuem dois nichos neurogênicos independentes: a zona subventricular (ZSV) e a zona subgranular (ZSG) do giro denteado. No entanto, a existência de nichos neurogênicos em humanos adultos é controversa. Nossa hipótese foi de que o mapeamento de nichos neurogênicos no lobo temporal humano poderia esclarecer aspectos sobre a neurogênese adulta. A detecção destes nichos foi buscada em 28 lobos temporais através de imuno-histoquímica para nestina, o marcador mais comum de células-tronco neurais, que são aquelas capazes de se autorrenovar e de gerar novas células neurais. A neurogênese foi pesquisada no hipocampo pelo uso de DCX (do inglês \"doublecortin\"), o principal marcador de neuroblastos e neurônios imaturos. Nestina foi observada em uma camada contínua formada pela ZSV, zona subpial do lobo temporal medial e ZSG, terminando no subículo. A partir do subículo, uma intensa expressão de DCX ocorreu através da principal via eferente do hipocampo até a fímbria. A visão panorâmica das marcações por nestina e DCX mostrava em conjunto uma linha que circundava as estruturas límbicas do lobo temporal. Por isto, foi denominada linha externa de células do sistema límbico (LECEL). Uma possível explicação para os resultados é que a LECEL seja um nicho neurogênico no qual a ZSV, a zona subpial do lobo temporal medial e a ZSG formam uma unidade contendo células-tronco neurais que se diferenciam em neurônios no subículo. Curiosamente, a área identificada previamente como sendo a corrente migratória rostral humana (formada por células neurais imaturas migrando a partir da ZSV do corno frontal) pode ser na verdade o fórnix, que contém axônios originados no subículo. A implicação mais intrigante dos resultados é que se as características da LECEL seguirem além do lobo temporal, então o encéfalo humano pode conter um anel neurogênico límbico, em que a neurogênese ocorreria principalmente no subículo e seria modulada pelas estruturas relacionadas à fissura coroideia. Este estudo sugere que a neurogênese ocorre de maneira orquestrada em uma área ampla do lobo temporal humano / At the end of the 19th century, the neuron was described as the basic functional unit of the nervous system. The formation of neurons was thought to be absent in adulthood, thus explaining the lack of significant recovery from neurological diseases. Evidence for the generation of neurons in adult mammals was reported in the 1960s and confirmed three decades later. Currently, the prevailing view is that adult mammals harbour two neurogenic niches: the subgranular zone (SGZ) of the dentate gyrus and the subventricular zone (SVZ). Nonetheless, the existence of these niches in adult humans is controversial. We hypothesised that mapping neurogenic niches in the human temporal lobe could clarify this issue. The presence of neurogenic niches was examined in 28 temporal lobes via immunostaining for nestin, the most common marker for neural stem cells, which are cells with the capacities of self-renewal and the generation of neural cells. The presence of neurogenesis was examined in the hippocampus with doublecortin (DCX), a prominent marker for neuroblasts and immature neurons. Nestin was observed in a continuous layer that was formed by the SVZ, the subpial zone of the medial temporal lobe and the SGZ, terminating in the subiculum. In the subiculum, remarkable DCX expression was observed through the principal efferent pathway of the hippocampus to the fimbria. A panoramic view of nestin and DCX staining collectively displayed a line that surrounded the limbic structures of the temporal lobe. Hence, we termed it the external line of cells of the limbic system (EXCEL). A possible explanation for the results is that the EXCEL is a neurogenic niche, in which the SVZ, the subpial zone of the medial temporal lobe and the SGZ form a unit containing neural stem cells that differentiate into neurons in the subiculum. Curiously, the area previously identified as the human rostral migratory stream (formed by immature neural cells that migrate from the SVZ of the frontal horn) may in truth be the fornix, which contains axons that originate in the subiculum. Perhaps most intriguingly, if the EXCEL acts as a neurogenic niche beyond the boundaries of the temporal lobe, the human brain may contain a limbic neurogenic ring, in which neurogenesis would occur in the subiculum through the modulation of choroid fissure-related structures. This study suggests that neurogenesis may occur in an orchestrated manner in a broad area of the human temporal lobe

Embryonen von Höheren Krebsen (Malacostraca) zeigen ein stereotypes Zellteilungsmuster im Ektoderm des Rumpfes, im Verlaufe dessen paarige seitliche Reihen von Zellen und eine unpaare mittlere Reihe von Zellen gebildet werden. Das Muster der seitlichen Zellen ist von Dohle (1970, 1976) und Mitarbeitern geklärt worden. Die vorliegende Arbeit untersucht die cell lineage und Zelldifferenzierung der Mittellinienzellen im Thorax. Diese Zellen sind von besonderem Interesse, weil sie bei Insekten bereits intensiv erforscht wurden. (i) Die DiI Markierungen von Mittellinienzellen von Orchestia cavimana zeigen: Die Bildung der Mittellinie beginnt mit einer Zelle, die sich zweimal in Längsrichtung teilt. Die resultierenden vier Zellen werden mit a0, b0, c0 und d0 bezeichtet. Aus den Zellen a0, b0 und c0 gehen Paare von Gliazellen hervor. Die Tochterzellen von a0 und c0 umhüllen die Kommissuren. Die Zelle d0 ist ein medianer Neuroblast, aus dem mehrere Neurone hervorgehen, unter anderem ein unpaares Neuron im medianen Fasertrakt, interneurone und ein Motoneuron. (ii)BrdU Markierungen von Porcellio scaber zeigen: In den Ganglienanlagen liegt in der Mittellinie je eine Zelle, die größer ist als die benachbarten, schneller proliferiert und deshalb vermutlich ein medianer Neuroblast ist. (iii) Die Expression von engrailed setzt bei Orchestia und Porcellio ein in der Zelle a0 und wird in den zwei Tochterzellen fortgesetzt. Für Orchestia wird gezeigt, daß diese Expression zurückgeht und die Tochterzellen der Zelle d0 de novo mit einer Expression von engrailed beginnen.Aus den Ergebnissen kann abgeleitet werden, daß der gemeinsame Vorfahr von Insekten und Höheren Krebsen eine Mittellinie differenziert, die Vorläufer für Glia der Kommissuren und einen medianen Neuroblasten umfaßt und eine Expression von engrailed in den Tochterzellen des Neuroblasten zeigt. / Embryos of higher crustaceans (Malacostraca) show a highly stereotypic cell division pattern in the ectoderm of the trunk region while forming paired rows of lateral cells and an unpaired median row of midline cells. By using nuclear dyes, the pattern of the lateral cells has been determined by Dohle (1970, 1976) an co-workers. This study addresses the cell lineage and cell differentiation of the midline cells in the thorax. These kind of cells are of particular interest as they have been investigated extensively in insects. (i) The DiI labelling of midline cells in Orchestia cavimana reveals: Formation of the midline starts with a single midline cell that divides twice in longitudinal direction. The resulting four cells are termed a0, b0, c0, and d0. The cells a0, b0, and c0 give rise to pairs of glial cells. The progeny of a0 and c0 enwrap the commissures. The cell d0 is a median neuroblast that gives rise to several neurons, among them an unpaired neuron in the median fibre tract, interneurons and probably a single motoneuron. (ii) BrdU labelling in Porcellio scaber shows: there is a single larger and faster dividing cell in the midline in each segmental ganglion anlage that is a putative median neuroblast. (iii)The expression of engrailed starts in Orchestia and Porcellio the cell a0 and continues in the two daughter cells during segmentation. In Orchestia it can be shown that this expression ceases and progenies of the cell d0 start de novo with the expression of engrailed. From the results can be concluded that the common ancestor of insects and higher crustaceans differentiated an unpaired midline comprising precursors for glial cells enwrapping the commissures and a single median neuroblast whose derivatives express engrailed.

O envelhecimento, processo iminente a todo ser vivo, no SNC é caracterizado por alterações como, por exemplo, a neuroinflamação crônica, que estão associadas a processos de neurodegeneração e ao aumento da incidência de doenças neurológicas ligadas ao surgimento de demência. A insulina, o hormônio anabólico mais importante descoberto até hoje, tem sua sinalização como processo vital que está presente desde bactérias até a espécie humana e desde os tecidos periféricos até o SNC. Mesmo a sinalização cerebral de insulina sendo um tema bem definido na literatura, pouco se sabe sobre a sua função em células da glia, principalmente astrócitos e microglia, componentes chaves do processo de neuroinflamação. A neuroinflamação foi considerada, por muitos anos, tóxica ao SNC, mas atualmente evidências importantes têm sido encontradas sugerindo que processos pró-inflamatórios são primariamente benéficos ao cérebro ou encéfalo e podem assumir papel tóxico à medida que se tornam crônico. Assim, considerando o papel da insulina no SNC, bem como o aumento da expectativa de vida da população mundial que acarreta o aumento dramático da incidência de doenças neurodegenerativas, foi investigada, na presente tese a relação da sinalização fisiológica de insulina com processos cognitivos, neurotróficos e neuroinflamatórios e também a resistência na sinalização da mesma causada pelo envelhecimento cerebral. Foi demonstrado que a administração intracerebroventricular de insulina melhora a cognição de animais jovens, mas o mesmo não ocorre no envelhecimento. A nível celular e molecular, foi visto um distúrbio na conexão da sinalização de insulina e BDNF, bem como na ativação microglial e sinalização pró-inflamatória da insulina que parecem estar comprometidos no envelhecimento. Além disso, foi observado que a microglia é sensível à sinalização direta de insulina via PI3K e que essa sinalização microglial é adaptada e sofre mudanças na vida adulta. Em conjunto com a literatura, foi demostrado por esta tese que existe uma ruptura de paradigmas na interpretação dos processos neuroinflamatórios, que deixam de ser vistos somente como um fator tóxico ao cérebro, mas também como um artifício elementar de adaptação do SNC aos diversos estímulos que as células nervosas recebem durante o curso da vida, desde o nascimento até o envelhecimento. / Aging is a process that is found in all living being in the CNS. It is characterized by modifications, such as chronic neuroinflammation, which are associated with neurodegeneration and represent a risk factor for neurological diseases. Insulin is the most important anabolic hormone ever discovered. Insulin signaling represents an essential process that is present from bacteria to humans and from the periphery to the brain. Insulin signaling in the CNS is a well-defined topic in the literature. Most of the knowledge regarding brain insulin signaling still report findings in neurons and little is known about insulin function in glia, especially astrocytes and microglia that are key players of neuroinflammation. Neuroinflammation has been considered a toxic factor to the CNS, however, in the last few years, important evidences have been found that proinflammatory processes are primarily beneficial and may play a toxic role as soon as they become chronic. Thus, considering the role of insulin in the CNS, as well as the increased populational life spam worldwide, the present thesis investigated the relation of physiological insulin signaling and the brain insulin signaling caused by aging in cognition, neurochemistry and neuroinflammation. We showed that insulin intracerebroventricular administration improved the cognition of young animals, but the same was not observed in aging. At the cellular and molecular level, we found a disruption in the connection of insulin and BDNF signaling. We also show that a microglial activation and pro-inflammation triggered by insulin in young brain appear to be lost during aging. In addition, it was observed that microglia is sensitive to direct insulin signaling via PI3K and that this microglial signaling suffers adaptations and changes during life. Together with the recently changes in the literature, the findings of this work demonstrate that there is a rupture of paradigms in the interpretation of neuroinflammatory processes, which are no longer seen only as a toxic factor to the brain, but also as an smart adaptation of the CNS to the various stimuli that brain cells receive during the course of life, from birth to aging.

La mutation à l’origine de la maladie de Huntington (MH) correspond à une expansion anormale de glutamines sur la protéine huntingtine (HTT). La MH est caractérisée par des symptômes moteurs et cognitifs mais également des troubles psychiatriques tels que l’anxiété et la dépression.Au cours de ma thèse, j’ai montré que la HTT module le statut anxio-dépressif de la souris via ses phosphorylations aux sérines 1181/1201. En effet, l’ablation des phosphorylations sur la HTT endogène améliore significativement le phénotype anxio-dépressif de la souris. Chez la souris, cette modulation dépend d’une augmentation de la maturation et de la survie des nouveaux neurones dans l’hippocampe. En effet, l’irradiation focale de l’hippocampe, dans un contexte où les phosphorylations sont absentes, supprime la neurogenèse et la réduction du statut anxio-dépressif observée en l’absence de phosphorylations. Au niveau moléculaire, la HTT non phosphorylée accroît l’association des moteurs moléculaires et des vésicules de BDNF sur les microtubules, ce qui augmente les dynamiques et la libération du BDNF. Ceci active la voie de signalisation MAPK/CREB dans l’hippocampe, cette voie pouvant ainsi stimuler la neurogenèse.J’ai ensuite étudié le rôle de ces phosphorylations dans un contexte MH et j’ai démontré l’effet anxiolytique/antidépresseur de l’absence de ces phosphorylations.J’ai également montré le rôle de ces phosphorylations de la HTT au cours du développement du cortex embryonnaire.Les résultats obtenus au cours de ma thèse suggèrent que les mécanismes fondamentaux de neurogenèse sont régulés par la HTT et ses phosphorylations. De plus, ils identifient une nouvelle voie de modulation de l’anxiété/dépression faisant intervenir la HTT. / Huntington disease (HD) is a fatal neurodegenerative disorder associated with early psychiatric symptoms including anxiety and depression.During my thesis, I have demonstrated that huntingtin, the protein mutated in HD, modulates anxiety/depression-related behaviors through its phosphorylations at serines 1181 and 1201. Indeed, genetic phospho-ablation at serines 1181 and 1201 in mouse reduces basal levels of anxiety/depression-like behaviors in mouse. Suppression of neurogenesis by focal hippocampal irradiation abolishes this reduction of basal levels of anxiety/depression on some behavioral test demonstrating that neurogenesis is involved in this process. Ablation of HTT phosphorylations may stimulate neurogenesis through BDNF transport, release and signaling.I have also shown that ablation of phosphorylations on HTT is sufficient to ameliorate the anxiety/depression-like behavior of a mouse model of HD, which develops a behavior indicative of depression–like state.I have finally explored the role of HTT phosphorylation at serines 1181 and 1201 during brain development. During early steps of cortical neurogenesis, I have shown that ablation of HTT phosphorylations affects the mitosis of cortical progenitors, the fate of newly generated cells and the migration of new neurons.The results obtained during my thesis support the notion that HTT regulates key molecular mechanisms during neurogenesis both in adult and embryo. It also supports the notion that huntingtin participates to anxiety and depression-like behavior with potential consequences for the etiology of mood disorders and anxiety/depression in HD.

La dépression majeure (DM) est une pathologie complexe et hétérogène associée avec des altérations du réseau cérébral, une dérégulation de l’axe hypothalamus-pituitaire-surrénales et avec des déficits de la neurogenèse adulte hippocampique (NHA). De nombreuses évidences pointent sur l’implication de la NHA dans les troubles de l’humeur et les troubles anxieux, ce qui a conduit à la formulation de l’ « hypothèse neurogénique », laquelle postule que des neurones néo-formés dans l’hippocampe du sujet adulte sont impliqués dans l’étiologie et dans l’efficacité du traitement de la DM. L’objectif de cette étude a été de déterminer le rôle des neurones formés à l’âge adulte après que les animaux aient été exposés à un stress ainsi que les mécanismes sous-jacents. Nos résultats suggèrent que l’augmentation de la neurogenèse est suffisante pour estomper les effets d’un stress chronique au niveau comportemental et hormonal, et donc pour induire un effet de type antidépresseur, comportementalement et physiologiquement. Les effets surviennent sans doute via le noyau du lit de la strie terminale antéro-dorsale. / Major depressive disorder (MDD) is a complex and heterogeneous disorder hypothesized to be associated with alterations in brain circuitry, dysregulations of the hypothalamic–pituitary–adrenal axis and impairments in adult hippocampal neurogenesis (AHN). Multiple lines of evidence point to the involvement of AHN in mood and anxiety disorders, leading to the formation of the “neurogenesis hypothesis”, which postulates that adult-born hippocampal neurons are involved in the etiology and treatment efficacy of MDD. The purpose of this study was to determine the role of adult-born neurons after the onset of stress exposure and the mechanism that underlies the observed results. Our results suggest that increasing neurogenesis is sufficient to buffer against the effects of chronic stress on certain behavioral and endocrine levels and thus to display antidepressant-like effects, both behaviorally and physiologically. Adult-born neurons might have exerted some of their effects via the anteromedial division of the bed nucleus of the stria terminalis (BSTMA).

SCRATCH2 é um fator de transcrição envolvido no desenvolvimento neural expresso em células pós-mitóticas. Identificamos que a retenção nuclear de SCRATCH2 é dada pelo domínio zinc-finger. A atividade repressora é modulada pelo domínio SCRATCH e não depende do domínio SNAG. O alinhamento de ortólogos de SCRATCH2 identificou uma sequência conservada na região N-terminal contendo os resíduos de fosforiláveis Y77 e S78. Mutação em Y77 ou S78 reduz a capacidade repressora de SCRATCH2, enquanto mutações em ambos resíduos resgatam sua função. Nossos dados sugerem que o domínio zinc-finger é responsável pela localização nuclear enquanto a atividade repressora é mediada pelo domínio SCRATCH. Já a identidade de Y77 e S78 é importante para a conformação correta proteína. O nocaute de SCRATCH2 aumenta a expressão de marcadores de progenitores intermediários (IP) e reduz o a expressão de marcadores de neurônios pós-mitóticos durante a neurodiferenciação de células-tronco. Esses dados sugerem que SCRATCH2 atua na manutenção de IP, e participa do início da diferenciação neural. / SCRATCH2 is a transcription factor involved in neural development expressed in postmitotic neural cells. Here, we identify that the nuclear retention of SCRATCH2 is controlled by the zinc-finger domain. The repressor activity is modulated by the SCRATCH domain and is independent of the SNAG domain. An analysis of SCRATCH2 through homology comparison identified a N-terminal conserved sequence containing two phosphorylatable residues, Y77 and S78. Single mutation in Y77 or S78 reduces SCRATCH2 repression ability while concomitant mutation in both rescue SCRATCH2 function. Our data suggest that the zinc-finger domain is responsible for nuclear retention of SCRATCH2 while residues Y77 and S78 are relevant for the protein correct conformation. In mouse embryonic stem cells neural induced towards corticogenesis, SCRATCH2 KO increases the levels of intermediate progenitors (IP) markers and reduces the level of early born neurons markers. This data suggests that SCRATCH2 plays a role in the maintenance of IP pool, thereby regulating the onset of neural differentiation.