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1.
Front Neurosci ; 17: 1026939, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36998737

RESUMO

The neurohormone oxytocin (OXT) has been implicated in the regulation of social behavior and is intensively investigated as a potential therapeutic treatment in neurodevelopmental disorders characterized by social deficits. In the Magel2-knockout (KO) mouse, a model of Schaaf-Yang Syndrome, an early postnatal administration of OXT rescued autistic-like behavior and cognition at adulthood, making this model relevant for understanding the actions of OXT in (re)programming postnatal brain development. The oxytocin receptor (OXTR), the main brain target of OXT, was dysregulated in the hippocampus of Magel2-KO adult males, and normalized upon OXT treatment at birth. Here we have analyzed male and female Magel2-KO brains at postnatal day 8 (P8) and at postnatal day 90 (P90), investigating age, genotype and OXT treatment effects on OXTR levels in several regions of the brain. We found that, at P8, male and female Magel2-KOs displayed a widespread, substantial, down-regulation of OXTR levels compared to wild type (WT) animals. Most intriguingly, the postnatal OXT treatment did not affect Magel2-KO OXTR levels at P8 and, consistently, did not rescue the ultrasonic vocalization deficits observed at this age. On the contrary, the postnatal OXT treatment reduced OXTR levels at P90 in male Magel2-KO in a region-specific way, restoring normal OXTR levels in regions where the Magel2-KO OXTR was upregulated (central amygdala, hippocampus and piriform cortex). Interestingly, Magel2-KO females, previously shown to lack the social deficits observed in Magel2-KO males, were characterized by a different trend in receptor expression compared to males; as a result, the dimorphic expression of OXTR observed in WT animals, with higher OXTR expression observed in females, was abolished in Magel2-KO mice. In conclusion, our data indicate that in Magel2-KO mice, OXTRs undergo region-specific modifications related to age, sex and postnatal OXT treatment. These results are instrumental to design precisely-timed OXT-based therapeutic strategies that, by acting at specific brain regions, could modify the outcome of social deficits in Schaaf-Yang Syndrome patients.

2.
Front Mol Neurosci ; 15: 1071719, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36583080

RESUMO

The nonapeptide oxytocin (OT) is a master regulator of the social brain in early infancy, adolescence, and adult life. Here, we review the postnatal dynamic development of OT-system as well as early-life OT functions that are essential for shaping social behaviors. We specifically address the role of OT in neonates, focusing on its role in modulating/adapting sensory input and feeding behavior; both processes are involved in the establishing mother-infant bond, a crucial event for structuring all future social interactions. In patients and rodent models of Prader-Willi and Schaaf-Yang syndromes, two neurodevelopmental diseases characterized by autism-related features, sensory impairments, and feeding difficulties in early infancy are linked to an alteration of OT-system. Successful preclinical studies in mice and a phase I/II clinical trial in Prader-Willi babies constitute a proof of concept that OT-treatment in early life not only improves suckling deficit but has also a positive long-term effect on learning and social behavior. We propose that in early postnatal life, OT plays a pivotal role in stimulating and coordinating the maturation of neuronal networks controlling feeding behavior and the first social interactions. Consequently, OT therapy might be considered to improve feeding behavior and, all over the life, social cognition, and learning capabilities.

3.
Transl Psychiatry ; 12(1): 318, 2022 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-35941105

RESUMO

The prosocial neuropeptide oxytocin is being developed as a potential treatment for various neuropsychiatric disorders including autism spectrum disorder (ASD). Early studies using intranasal oxytocin in patients with ASD yielded encouraging results and for some time, scientists and affected families placed high hopes on the use of intranasal oxytocin for behavioral therapy in ASD. However, a recent Phase III trial obtained negative results using intranasal oxytocin for the treatment of behavioral symptoms in children with ASD. Given the frequently observed autism-like behavioral phenotypes in Prader-Willi and Schaaf-Yang syndromes, it is unclear whether oxytocin treatment represents a viable option to treat behavioral symptoms in these diseases. Here we review the latest findings on intranasal OT treatment, Prader-Willi and Schaaf-Yang syndromes, and propose novel research strategies for tailored oxytocin-based therapies for affected individuals. Finally, we propose the critical period theory, which could explain why oxytocin-based treatment seems to be most efficient in infants, but not adolescents.


Assuntos
Transtorno do Espectro Autista , Síndrome de Prader-Willi , Administração Intranasal , Artrogripose , Transtorno do Espectro Autista/tratamento farmacológico , Anormalidades Craniofaciais , Humanos , Hipopituitarismo , Deficiência Intelectual , Ocitocina/uso terapêutico , Síndrome de Prader-Willi/tratamento farmacológico , Projetos de Pesquisa
4.
Neuropsychopharmacology ; 47(11): 1901-1912, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35396500

RESUMO

Atypical responses to sensory stimuli are considered as a core aspect and early life marker of autism spectrum disorders (ASD). Although recent findings performed in mouse ASD genetic models report sensory deficits, these were explored exclusively during juvenile or adult period. Whether sensory dysfunctions might be present at the early life stage and rescued by therapeutic strategy are fairly uninvestigated. Here we found that under cool environment neonatal mice lacking the autism-associated gene Magel2 present pup calls hypo-reactivity and are retrieved with delay by their wild-type dam. This neonatal atypical sensory reactivity to cool stimuli was not associated with autonomic thermoregulatory alteration but with a deficit of the oxytocinergic system. Indeed, we show in control neonates that pharmacogenetic inactivation of hypothalamic oxytocin neurons mimicked atypical thermosensory reactivity found in Magel2 mutants. Furthermore, pharmacological intranasal administration of oxytocin to Magel2 neonates was able to rescue both the atypical thermosensory response and the maternal pup retrieval. This preclinical study establishes for the first-time early life impairments in thermosensory integration and suggest a therapeutic potential benefit of intranasal oxytocin treatment on neonatal atypical sensory reactivity for autism.


Assuntos
Transtorno Autístico , Hipestesia , Comportamento Materno , Ocitocina , Proteínas , Administração Intranasal , Fatores Etários , Animais , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/metabolismo , Transtorno do Espectro Autista/complicações , Transtorno Autístico/complicações , Transtorno Autístico/genética , Transtorno Autístico/metabolismo , Fármacos do Sistema Nervoso Central/administração & dosagem , Fármacos do Sistema Nervoso Central/metabolismo , Feminino , Hipestesia/etiologia , Hipestesia/genética , Hipestesia/metabolismo , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Comportamento Materno/fisiologia , Camundongos , Ocitocina/administração & dosagem , Ocitocina/metabolismo , Proteínas/genética , Proteínas/metabolismo , Comportamento Social
5.
Front Mol Neurosci ; 15: 1075305, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36698777

RESUMO

Oxytocin (OT) is a neurohormone involved early in neurodevelopment and is implicated in multiple functions, including sensory modulation. Evidence of such modulation has been observed for different sensory modalities in both healthy and pathological conditions. This review summarizes the pleiotropic modulation that OT can exercise on an often overlooked sensory system: thermosensation. This system allows us to sense temperature variations and compensate for the variation to maintain a stable core body temperature. Oxytocin modulates autonomic and behavioral mechanisms underlying thermoregulation at both central and peripheral levels. Hyposensitivity or hypersensitivity for different sensory modalities, including thermosensitivity, is a common feature in autism spectrum disorder (ASD), recapitulated in several ASD mouse models. These sensory dysregulations occur early in post-natal development and are correlated with dysregulation of the oxytocinergic system. In this study, we discussed the potential link between thermosensory atypia and the dysregulation of the oxytocinergic system in ASD.

6.
Biol Aujourdhui ; 216(3-4): 131-143, 2022.
Artigo em Francês | MEDLINE | ID: mdl-36744979

RESUMO

Oxytocin (OT) is a neurohormone that regulates the so-called "social brain" and is mainly studied in adulthood. During postnatal development, the mechanisms by which the OT system structures various behaviors are little studied. Here we present the dynamic process of postnatal development of the OT system as well as the OT functions in the perinatal period that are essential for shaping social behaviors. Specifically, we discuss the role of OT, in the newborn, in integrating and adapting responses to early sensory stimuli and in stimulating suckling activity. Sensory dialogue and suckling are involved in mother-infant bonds and structure future social interactions. In rodents and humans, neurodevelopmental diseases with autism spectrum disorders (ASD), such as Prader-Willi and Schaaf-Yang syndromes, are associated with sensory, feeding and behavioral deficits in infancy. We propose that in early postnatal life, OT plays a key role in stimulating the maturation of neural networks controlling feeding behavior and early social interactions from birth. Administration of OT at birth improves sensory integration of environmental factors and the relationship with the mother as well as sucking activity as we have shown in mouse models and in babies with Prader-Willi syndrome. Long-term effects have also been observed on social and cognitive behavior. Therefore, early feeding difficulties might be an early predictive marker of ASD, and OT treatment a promising option to improve feeding behavior and, in the longer term, social behavioral problems.


Title: L'ocytocine, dès la naissance, conditionne le comportement alimentaire et social d'un individu. Abstract: L'ocytocine (OT) est une neurohormone qui, dans le cerveau, régule ce que l'on appelle le « cerveau social ¼ et dont l'étude est principalement conduite chez l'adulte. Au cours du développement postnatal, les mécanismes par lesquels le système OT structure divers comportements sont peu explorés. Nous présentons ici le processus dynamique du développement postnatal du système OT ainsi que ses rôles fonctionnels, en période périnatale, qui sont essentiels pour façonner les comportements sociaux. Nous abordons spécifiquement le rôle de l'OT chez le nouveau-né, qui permet d'intégrer et d'adapter des réponses aux premières stimulations sensorielles et qui stimule aussi l'activité de succion. Ce dialogue sensoriel et la tétée sont impliqués dans les liens mère-enfant et structurent les futures interactions sociales. Chez les rongeurs et chez l'homme, des maladies neuro-développementales avec des troubles du spectre autistique, comme les syndromes de Prader-Willi et de Schaaf-Yang, sont associées à des déficiences sensorielles, alimentaires et comportementales dans la petite enfance. Nous proposons qu'au début de la vie postnatale, l'OT joue un rôle clé dans la maturation des réseaux neuronaux contrôlant le comportement alimentaire et les premières interactions sociales. Une administration d'OT chez le nouveau-né améliore l'intégration sensorielle des facteurs environnementaux et la relation avec la mère ainsi que l'activité de succion comme nous l'avons montré chez des modèles de souris ainsi que chez des bébés atteints du syndrome de Prader-Willi. Des effets à long terme ont aussi été observés sur le comportement social et cognitif. Par conséquent, les difficultés précoces d'alimentation peuvent être un marqueur prédictif précoce des cas de troubles du spectre autistique (TSA) et l'administration exogène d'OT pourrait améliorer le comportement alimentaire et, à plus long terme, les troubles du comportement social.


Assuntos
Ocitocina , Síndrome de Prader-Willi , Humanos , Recém-Nascido , Animais , Camundongos , Comportamento Social , Encéfalo , Síndrome de Prader-Willi/psicologia , Comportamento Alimentar
8.
Mol Psychiatry ; 26(12): 7582-7595, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34290367

RESUMO

Oxytocin is an important regulator of the social brain. In some animal models of autism, notably in Magel2tm1.1Mus-deficient mice, peripheral administration of oxytocin in infancy improves social behaviors until adulthood. However, neither the mechanisms responsible for social deficits nor the mechanisms by which such oxytocin administration has long-term effects are known. Here, we aimed to clarify these oxytocin-dependent mechanisms, focusing on social memory performance. Using in situ hybridization (RNAscope), we have established that Magel2 and oxytocin receptor are co-expressed in the dentate gyrus and CA2/CA3 hippocampal regions involved in the circuitry underlying social memory. Then, we have shown that Magel2tm1.1Mus-deficient mice, evaluated in a three-chamber test, present a deficit in social memory. Next, in hippocampus, we conducted neuroanatomical and functional studies using immunostaining, oxytocin-binding experiments, ex vivo electrophysiological recordings, calcium imaging and biochemical studies. We demonstrated: an increase of the GABAergic activity of CA3-pyramidal cells associated with an increase in the quantity of oxytocin receptors and of somatostatin interneurons in both DG and CA2/CA3 regions. We also revealed a delay in the GABAergic development sequence in Magel2tm1.1Mus-deficient pups, linked to phosphorylation modifications of KCC2. Above all, we demonstrated the positive effects of subcutaneous administration of oxytocin in the mutant neonates, restoring hippocampal alterations and social memory at adulthood. Although clinical trials are debated, this study highlights the mechanisms by which peripheral oxytocin administration in neonates impacts the brain and demonstrates the therapeutic value of oxytocin to treat infants with autism spectrum disorders.


Assuntos
Transtorno Autístico , Ocitocina , Animais , Antígenos de Neoplasias/uso terapêutico , Transtorno Autístico/tratamento farmacológico , Hipocampo/metabolismo , Camundongos , Ocitocina/uso terapêutico , Proteínas , Receptores de Ocitocina/metabolismo , Comportamento Social
9.
Dev Neurobiol ; 81(4): 366-388, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33609001

RESUMO

Oxytocin contributes to the regulation of cytoskeletal and synaptic proteins and could, therefore, affect the mechanisms of neurodevelopmental disorders, including autism. Both the Prader-Willi syndrome and Schaaf-Yang syndrome exhibit autistic symptoms involving the MAGEL2 gene. Magel2-deficient mice show a deficit in social behavior that is rescued following the postnatal administration of oxytocin. Here, in Magel2-deficient mice, we showed that the neurite outgrowth of primary cultures of immature hippocampal neurons is reduced. Treatment with oxytocin reversed this abnormality. In the hippocampus of Magel2-deficient pups, we further demonstrated that several transcripts of neurite outgrowth-associated proteins, synaptic vesicle proteins, and cell-adhesion molecules are decreased. In the juvenile stage, when neurons are mature, normalization or even overexpression of most of these markers was observed, suggesting a delay in the neuronal maturation of Magel2-deficient pups. Moreover, we found reduced transcripts of the excitatory postsynaptic marker, Psd95 in the hippocampus and we observed a decrease of PSD95/VGLUT2 colocalization in the hippocampal CA1 and CA3 regions in Magel2-deficient mice, indicating a defect in glutamatergic synapses. Postnatal administration of oxytocin upregulated postsynaptic transcripts in pups; however, it did not restore the level of markers of glutamatergic synapses in Magel2-deficient mice. Overall, Magel2 deficiency leads to abnormal neurite outgrowth and reduced glutamatergic synapses during development, suggesting abnormal neuronal maturation. Oxytocin stimulates the expression of numerous genes involved in neurite outgrowth and synapse formation in early development stages. Postnatal oxytocin administration has a strong effect on development that should be considered for certain neuropsychiatric conditions in infancy.


Assuntos
Transtorno Autístico , Síndrome de Prader-Willi , Animais , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/metabolismo , Transtorno Autístico/genética , Camundongos , Crescimento Neuronal , Ocitocina/farmacologia , Síndrome de Prader-Willi/genética , Proteínas/genética
10.
J Clin Invest ; 131(2)2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33232306

RESUMO

Intellectual and social disabilities are common comorbidities in adolescents and adults with MAGE family member L2 (MAGEL2) gene deficiency characterizing the Prader-Willi and Schaaf-Yang neurodevelopmental syndromes. The cellular and molecular mechanisms underlying the risk for autism in these syndromes are not understood. We asked whether vasopressin functions are altered by MAGEL2 deficiency and whether a treatment with vasopressin could alleviate the disabilities of social behavior. We used Magel2-knockout mice (adult males) combined with optogenetic or pharmacological tools to characterize disease modifications in the vasopressinergic brain system and monitor its impact on neurophysiological and behavioral functions. We found that the activation of vasopressin neurons and projections in the lateral septum were inappropriate for performing a social habituation/discrimination task. Mechanistically, the lack of vasopressin impeded the deactivation of somatostatin neurons in the lateral septum, which predicted social discrimination deficits. Correction of vasopressin septal content by administration or optogenetic stimulation of projecting axons suppressed the activity of somatostatin neurons and ameliorated social behavior. This preclinical study identified vasopressin in the lateral septum as a key factor in the pathophysiology of Magel2-related neurodevelopmental syndromes.


Assuntos
Antígenos de Neoplasias/genética , Transtorno Autístico , Comportamento Animal , Proteínas/genética , Núcleos Septais , Comportamento Social , Vasopressinas , Animais , Antígenos de Neoplasias/metabolismo , Transtorno Autístico/tratamento farmacológico , Transtorno Autístico/genética , Transtorno Autístico/metabolismo , Transtorno Autístico/fisiopatologia , Modelos Animais de Doenças , Humanos , Masculino , Camundongos , Camundongos Knockout , Neurônios/metabolismo , Neurônios/patologia , Proteínas/metabolismo , Núcleos Septais/metabolismo , Núcleos Septais/fisiopatologia , Vasopressinas/deficiência , Vasopressinas/farmacologia
11.
Hum Mol Genet ; 29(12): 2065-2075, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32420597

RESUMO

Prader-Willi syndrome (PWS) is caused by deficient expression of the paternal copy of several contiguous genes on chromosome 15q11-q13 and affects multiple organ systems in the body, including the nervous system. Feeding and suckling deficits in infants with PWS are replaced with excessive feeding and obesity in childhood through adulthood. Clinical trials using intranasal oxytocin (OXT) show promise to improve feeding deficits in infants with PWS. The mechanism and location of action of exogenous OXT are unknown. We have recently shown in neonatal mice that OXT receptors (OXTR) are present in several regions of the face with direct roles in feeding. Here we show that the trigeminal ganglion, which provides sensory innervation to the face, is a rich source of Oxtr and a site of cellular co-expression with PWS gene transcripts. We also quantified OXTR ligand binding in mice deficient in Magel2, a PWS gene, within the trigeminal ganglion and regions that are anatomically relevant to feeding behavior and innervated by the trigeminal ganglion including the lateral periodontium, rostral periodontium, tongue, olfactory epithelium, whisker pads and brainstem. We found that peripheral OXTR ligand binding in the head is mostly intact in Magel2-deficient mice, although it is reduced in the lateral periodontium (gums) of neonatal Magel2-deficient mice compared to wild-type controls. These data suggest that OXT via orofacial OXTR may play a peripheral role to modulate sensory-motor reflexes necessary for suckling and may be part of the mechanism by which intranasal OXT shows promise for therapeutic benefit in PWS.


Assuntos
Antígenos de Neoplasias/genética , Ocitocina/genética , Obesidade Pediátrica/genética , Síndrome de Prader-Willi/genética , Proteínas/genética , Receptores de Ocitocina/genética , Adulto , Animais , Animais Recém-Nascidos , Criança , Impressão Genômica/genética , Humanos , Camundongos , Obesidade Pediátrica/metabolismo , Obesidade Pediátrica/patologia , Síndrome de Prader-Willi/metabolismo , Síndrome de Prader-Willi/patologia , Gânglio Trigeminal/metabolismo , Gânglio Trigeminal/patologia
12.
Curr Opin Neurobiol ; 52: 165-171, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30032064

RESUMO

From birth, mammals have to find food and maximize caloric intake to ensure growth and survival. Suckling must be initiated quickly after birth and then maintained and controlled until weaning. It is a complex process involving interactions between sensory and motor neuronal pathways. Meanwhile, the control of food intake and energy homeostasis is progressively established via the development of hypothalamic circuits. The development of these circuits is influenced by hormonal and nutritional signals and can be disturbed in a variety of developmental disorders leading to long-term metabolic, behavioral and cognitive dysfunctions. This review summarizes our current knowledge of the neuronal circuits involved in early postnatal feeding processes.


Assuntos
Comportamento Alimentar/fisiologia , Homeostase/fisiologia , Hipotálamo/fisiologia , Rede Nervosa/fisiologia , Percepção Olfatória/fisiologia , Comportamento de Sucção/fisiologia , Percepção do Tato/fisiologia , Animais , Humanos , Hipotálamo/crescimento & desenvolvimento , Hipotálamo/metabolismo , Rede Nervosa/crescimento & desenvolvimento , Rede Nervosa/metabolismo
14.
Curr Top Behav Neurosci ; 35: 239-268, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-28812269

RESUMO

Oxytocin plays a role in various functions including endocrine and immune functions but also parent-infant bonding and social interactions. It might be considered as a main neuropeptide involved in mediating the regulation of adaptive interactions between an individual and his/her environment. Recently, a critical role of oxytocin in early life has been revealed in sensory processing and multi-modal integration that are essential for normal postnatal neurodevelopment. An early alteration in the oxytocin-system may disturb its maturation and may have short-term and long-term pathological consequences such as autism spectrum disorders. Here, we will synthesize the existing literature on the development of the oxytocin system and its role in the early postnatal life of mammals (from birth to weaning) in a normal or pathological context. Oxytocin is required in critical windows of time that play a pivotal role and that should be considered for therapeutical interventions.


Assuntos
Transtorno do Espectro Autista/metabolismo , Encéfalo/metabolismo , Desenvolvimento Infantil/fisiologia , Relações Interpessoais , Ocitocina/metabolismo , Animais , Humanos , Recém-Nascido , Transdução de Sinais/fisiologia
15.
Elife ; 62017 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-29087295

RESUMO

Prader-Willi syndrome (PWS) is a genetic neurodevelopmental disorder that presents with hypotonia and respiratory distress in neonates. The Necdin-deficient mouse is the only model that reproduces the respiratory phenotype of PWS (central apnea and blunted response to respiratory challenges). Here, we report that Necdin deletion disturbs the migration of serotonin (5-HT) neuronal precursors, leading to altered global serotonergic neuroarchitecture and increased spontaneous firing of 5-HT neurons. We show an increased expression and activity of 5-HT Transporter (SERT/Slc6a4) in 5-HT neurons leading to an increase of 5-HT uptake. In Necdin-KO pups, the genetic deletion of Slc6a4 or treatment with Fluoxetine, a 5-HT reuptake inhibitor, restored normal breathing. Unexpectedly, Fluoxetine administration was associated with respiratory side effects in wild-type animals. Overall, our results demonstrate that an increase of SERT activity is sufficient to cause the apneas in Necdin-KO pups, and that fluoxetine may offer therapeutic benefits to PWS patients with respiratory complications.


Assuntos
Potenciais de Ação , Apneia/fisiopatologia , Proteínas do Tecido Nervoso/metabolismo , Proteínas Nucleares/metabolismo , Síndrome de Prader-Willi/fisiopatologia , Neurônios Serotoninérgicos/patologia , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Animais , Modelos Animais de Doenças , Deleção de Genes , Camundongos , Proteínas do Tecido Nervoso/deficiência , Proteínas Nucleares/deficiência , Serotonina/metabolismo
16.
Pediatrics ; 139(2)2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28100688

RESUMO

BACKGROUND AND OBJECTIVES: Patients with Prader-Willi syndrome (PWS) display poor feeding and social skills as infants and fewer hypothalamic oxytocin (OXT)-producing neurons were documented in adults. Animal data demonstrated that early treatment with OXT restores sucking after birth. Our aim is to reproduce these data in infants with PWS. METHODS: We conducted a phase 2 escalating dose study of a short course (7 days) of intranasal OXT administration. We enrolled 18 infants with PWS under 6 months old (6 infants in each step) who received 4 IU of OXT either every other day, daily, or twice daily. We investigated the tolerance and the effects on feeding and social skills and changes in circulating ghrelin and brain connectivity by functional MRI. RESULTS: No adverse events were reported. No dose effect was observed. Sucking assessed by the Neonatal Oral-Motor Scale was abnormal in all infants at baseline and normalized in 88% after treatment. The scores of Neonatal Oral-Motor Scale and videofluoroscopy of swallowing significantly decreased from 16 to 9 (P < .001) and from 18 to 12.5 (P < .001), respectively. Significant improvements in Clinical Global Impression scale scores, social withdrawal behavior, and mother-infant interactions were observed. We documented a significant increase in acylated ghrelin and connectivity of the right superior orbitofrontal network that correlated with changes in sucking and behavior. CONCLUSIONS: OXT is well tolerated in infants with PWS and improves feeding and social skills. These results open perspectives for early treatment in neurodevelopment diseases with feeding problems.


Assuntos
Comportamento Alimentar/efeitos dos fármacos , Ocitocina/uso terapêutico , Síndrome de Prader-Willi/tratamento farmacológico , Habilidades Sociais , Administração Intranasal , Pré-Escolar , Relação Dose-Resposta a Droga , Esquema de Medicação , Feminino , Seguimentos , Humanos , Lactente , Masculino , Relações Mãe-Filho , Ocitocina/administração & dosagem , Ocitocina/sangue , Síndrome de Prader-Willi/sangue , Comportamento de Sucção/efeitos dos fármacos
17.
Biol Psychiatry ; 78(2): 85-94, 2015 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-25599930

RESUMO

BACKGROUND: Mutations of MAGEL2 have been reported in patients presenting with autism, and loss of MAGEL2 is also associated with Prader-Willi syndrome, a neurodevelopmental genetic disorder. This study aimed to determine the behavioral phenotype of Magel2-deficient adult mice, to characterize the central oxytocin (OT) system of these mutant mice, and to test the curative effect of a peripheral OT treatment just after birth. METHODS: We assessed the social and cognitive behavior of Magel2-deficient mice, analyzed the OT system of mutant mice treated or not by a postnatal administration of OT, and determined the effect of this treatment on the brain. RESULTS: Magel2 inactivation induces a deficit in social recognition and social interaction and a reduced learning ability in adult male mice. In these mice, we reveal anatomical and functional modifications of the OT system and show that these defects change from birth to adulthood. Daily administration of OT in the first postnatal week was sufficient to prevent deficits in social behavior and learning abilities in adult mutant male mice. We show that this OT treatment partly restores a normal OT system. Thus, we report that an alteration of the OT system around birth has long-term consequences on behavior and on cognition. Importantly, an acute OT treatment of Magel2-deficient pups has a curative effect. CONCLUSIONS: Our study reveals that OT plays a crucial role in setting social behaviors during a period just after birth. An early OT treatment in this critical period could be a novel therapeutic approach for the treatment of neurodevelopmental disorders such as Prader-Willi syndrome and autism.


Assuntos
Antígenos de Neoplasias/genética , Transtorno Autístico/genética , Ocitocina/administração & dosagem , Síndrome de Prader-Willi/genética , Proteínas/genética , Comportamento Social , Animais , Transtorno Autístico/tratamento farmacológico , Transtorno Autístico/psicologia , Encéfalo/metabolismo , Cognição/efeitos dos fármacos , Cognição/fisiologia , Modelos Animais de Doenças , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ocitocina/metabolismo , Ocitocina/farmacocinética , Ocitocina/uso terapêutico , Síndrome de Prader-Willi/tratamento farmacológico , Síndrome de Prader-Willi/psicologia , Reconhecimento Psicológico/efeitos dos fármacos , Reconhecimento Psicológico/fisiologia , Aprendizagem Espacial/efeitos dos fármacos , Aprendizagem Espacial/fisiologia
18.
Front Neuroanat ; 8: 164, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25767437

RESUMO

Oxytocin (OT), the main neuropeptide of sociality, is expressed in neurons exclusively localized in the hypothalamus. During the last decade, a plethora of neuroendocrine, metabolic, autonomic and behavioral effects of OT has been reported. In the urgency to find treatments to syndromes as invalidating as autism, many clinical trials have been launched in which OT is administered to patients, including adolescents and children. However, the impact of OT on the developing brain and in particular on the embryonic and early postnatal maturation of OT neurons, has been only poorly investigated. In the present review we summarize available (although limited) literature on general features of ontogenetic transformation of the OT system, including determination, migration and differentiation of OT neurons. Next, we discuss trajectories of OT receptors (OTR) in the perinatal period. Furthermore, we provide evidence that early alterations, from birth, in the central OT system lead to severe neurodevelopmental diseases such as feeding deficit in infancy and severe defects in social behavior in adulthood, as described in Prader-Willi syndrome (PWS). Our review intends to propose a hypothesis about developmental dynamics of central OT pathways, which are essential for survival right after birth and for the acquisition of social skills later on. A better understanding of the embryonic and early postnatal maturation of the OT system may lead to better OT-based treatments in PWS or autism.

19.
PLoS Genet ; 9(9): e1003752, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24039599

RESUMO

Genomic imprinting is a process that causes genes to be expressed from one allele only according to parental origin, the other allele being silent. Diseases can arise when the normally active alleles are not expressed. In this context, low level of expression of the normally silent alleles has been considered as genetic noise although such expression has never been further studied. Prader-Willi Syndrome (PWS) is a neurodevelopmental disease involving imprinted genes, including NDN, which are only expressed from the paternally inherited allele, with the maternally inherited allele silent. We present the first in-depth study of the low expression of a normally silent imprinted allele, in pathological context. Using a variety of qualitative and quantitative approaches and comparing wild-type, heterozygous and homozygous mice deleted for Ndn, we show that, in absence of the paternal Ndn allele, the maternal Ndn allele is expressed at an extremely low level with a high degree of non-genetic heterogeneity. The level of this expression is sex-dependent and shows transgenerational epigenetic inheritance. In about 50% of mutant mice, this expression reduces birth lethality and severity of the breathing deficiency, correlated with a reduction in the loss of serotonergic neurons. In wild-type brains, the maternal Ndn allele is never expressed. However, using several mouse models, we reveal a competition between non-imprinted Ndn promoters which results in monoallelic (paternal or maternal) Ndn expression, suggesting that Ndn allelic exclusion occurs in the absence of imprinting regulation. Importantly, specific expression of the maternal NDN allele is also detected in post-mortem brain samples of PWS individuals. Our data reveal an unexpected epigenetic flexibility of PWS imprinted genes that could be exploited to reactivate the functional but dormant maternal alleles in PWS. Overall our results reveal high non-genetic heterogeneity between genetically identical individuals that might underlie the variability of the phenotype.


Assuntos
Epigênese Genética/genética , Impressão Genômica , Proteínas do Tecido Nervoso/genética , Proteínas Nucleares/genética , Síndrome de Prader-Willi/genética , Alelos , Animais , Apneia/genética , Apneia/patologia , Encéfalo/metabolismo , Encéfalo/patologia , Modelos Animais de Doenças , Regulação da Expressão Gênica , Heterozigoto , Humanos , Camundongos , Camundongos Knockout , Proteínas do Tecido Nervoso/metabolismo , Proteínas Nucleares/metabolismo , Síndrome de Prader-Willi/patologia , Regiões Promotoras Genéticas
20.
Brain ; 136(Pt 8): 2457-73, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23831613

RESUMO

Altered development of the human cerebral cortex can cause severe malformations with often intractable focal epileptic seizures and may participate in common pathologies, notably epilepsy. This raises important conceptual and therapeutic issues. Two missense mutations in the sushi repeat-containing protein SRPX2 had been previously identified in epileptic disorders with or without structural developmental alteration of the speech cortex. In the present study, we aimed to decipher the precise developmental role of SRPX2, to have a better knowledge on the consequences of its mutations, and to start addressing therapeutic issues through the design of an appropriate animal model. Using an in utero Srpx2 silencing approach, we show that SRPX2 influences neuronal migration in the developing rat cerebral cortex. Wild-type, but not the mutant human SRPX2 proteins, rescued the neuronal migration phenotype caused by Srpx2 silencing in utero, and increased alpha-tubulin acetylation. Following in utero Srpx2 silencing, spontaneous epileptiform activity was recorded post-natally. The neuronal migration defects and the post-natal epileptic consequences were prevented early in embryos by maternal administration of tubulin deacetylase inhibitor tubacin. Hence epileptiform manifestations of developmental origin could be prevented in utero, using a transient and drug-based therapeutic protocol.


Assuntos
Anilidas/farmacologia , Movimento Celular/genética , Córtex Cerebral/metabolismo , Epilepsia/genética , Inibidores de Histona Desacetilases/farmacologia , Ácidos Hidroxâmicos/farmacologia , Proteínas de Membrana/genética , Neurônios/metabolismo , Animais , Movimento Celular/efeitos dos fármacos , Córtex Cerebral/citologia , Córtex Cerebral/efeitos dos fármacos , Epilepsia/metabolismo , Inativação Gênica , Humanos , Neurônios/citologia , Neurônios/efeitos dos fármacos , Ratos , Tubulina (Proteína)/genética , Tubulina (Proteína)/metabolismo
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