RESUMEN
Transgenerational epigenetic inheritance in mammals remains a debated subject. Here, we demonstrate that DNA methylation of promoter-associated CpG islands (CGIs) can be transmitted from parents to their offspring in mice. We generated DNA methylation-edited mouse embryonic stem cells (ESCs), in which CGIs of two metabolism-related genes, the Ankyrin repeat domain 26 and the low-density lipoprotein receptor, were specifically methylated and silenced. DNA methylation-edited mice generated by microinjection of the methylated ESCs exhibited abnormal metabolic phenotypes. Acquired methylation of the targeted CGI and the phenotypic traits were maintained and transmitted across multiple generations. The heritable CGI methylation was subjected to reprogramming in parental PGCs and subsequently reestablished in the next generation at post-implantation stages. These observations provide a concrete step toward demonstrating transgenerational epigenetic inheritance in mammals, which may have implications in our understanding of evolutionary biology as well as the etiology, diagnosis, and prevention of non-genetically inherited human diseases.
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Metilación de ADN , Epigénesis Genética , Ratones , Humanos , Animales , Islas de CpG , Patrón de Herencia , Mamíferos/genéticaRESUMEN
Aging and circadian rhythms have been linked for decades, but their molecular interplay has remained obscure. Sato et al. and Solanas et al. now reveal that, while core clock components remain nearly unaltered, aging is associated with tissue-specific rewiring, which can be prevented by calorie restriction.
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Envejecimiento , Ritmo Circadiano , Restricción CalóricaRESUMEN
Current genome-editing systems generally rely on inducing DNA double-strand breaks (DSBs). This may limit their utility in clinical therapies, as unwanted mutations caused by DSBs can have deleterious effects. CRISPR/Cas9 system has recently been repurposed to enable target gene activation, allowing regulation of endogenous gene expression without creating DSBs. However, in vivo implementation of this gain-of-function system has proven difficult. Here, we report a robust system for in vivo activation of endogenous target genes through trans-epigenetic remodeling. The system relies on recruitment of Cas9 and transcriptional activation complexes to target loci by modified single guide RNAs. As proof-of-concept, we used this technology to treat mouse models of diabetes, muscular dystrophy, and acute kidney disease. Results demonstrate that CRISPR/Cas9-mediated target gene activation can be achieved in vivo, leading to measurable phenotypes and amelioration of disease symptoms. This establishes new avenues for developing targeted epigenetic therapies against human diseases. VIDEO ABSTRACT.
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Sistemas CRISPR-Cas , Epigénesis Genética , Marcación de Gen/métodos , Terapia Genética/métodos , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/terapia , Utrofina/genética , Animales , Secuencia de Bases , Modelos Animales de Enfermedad , Distrofina/genética , Interleucina-10/genética , Proteínas Klotho , Proteínas de la Membrana/genética , Ratones , Ratones Endogámicos C57BL , Activación TranscripcionalRESUMEN
Aging is the major risk factor for many human diseases. In vitro studies have demonstrated that cellular reprogramming to pluripotency reverses cellular age, but alteration of the aging process through reprogramming has not been directly demonstrated in vivo. Here, we report that partial reprogramming by short-term cyclic expression of Oct4, Sox2, Klf4, and c-Myc (OSKM) ameliorates cellular and physiological hallmarks of aging and prolongs lifespan in a mouse model of premature aging. Similarly, expression of OSKM in vivo improves recovery from metabolic disease and muscle injury in older wild-type mice. The amelioration of age-associated phenotypes by epigenetic remodeling during cellular reprogramming highlights the role of epigenetic dysregulation as a driver of mammalian aging. Establishing in vivo platforms to modulate age-associated epigenetic marks may provide further insights into the biology of aging.
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Envejecimiento/genética , Reprogramación Celular , Epigénesis Genética , Enfermedades Metabólicas/genética , Factores de Transcripción/metabolismo , Envejecimiento Prematuro/genética , Envejecimiento Prematuro/metabolismo , Animales , Diabetes Mellitus Tipo 2/inducido químicamente , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Células Madre Pluripotentes Inducidas/metabolismo , Factor 4 Similar a Kruppel , Lamina Tipo A/genética , Enfermedades Metabólicas/metabolismo , Enfermedades Metabólicas/prevención & control , Ratones , Modelos Animales , Páncreas/metabolismo , Sarcopenia/metabolismoRESUMEN
Substantial evidence suggests that chromosomal abnormalities contribute to the risk of autism. The duplication of human chromosome 15q11-13 is known to be the most frequent cytogenetic abnormality in autism. We have modeled this genetic change in mice by using chromosome engineering to generate a 6.3 Mb duplication of the conserved linkage group on mouse chromosome 7. Mice with a paternal duplication display poor social interaction, behavioral inflexibility, abnormal ultrasonic vocalizations, and correlates of anxiety. An increased MBII52 snoRNA within the duplicated region, affecting the serotonin 2c receptor (5-HT2cR), correlates with altered intracellular Ca(2+) responses elicited by a 5-HT2cR agonist in neurons of mice with a paternal duplication. This chromosome-engineered mouse model for autism seems to replicate various aspects of human autistic phenotypes and validates the relevance of the human chromosome abnormality. This model will facilitate forward genetics of developmental brain disorders and serve as an invaluable tool for therapeutic development.
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Trastorno Autístico/genética , Trastorno Autístico/fisiopatología , Conducta Animal , Cromosomas Humanos Par 15 , Modelos Animales de Enfermedad , Animales , Cromosomas de los Mamíferos , Expresión Génica , Humanos , Relaciones Interpersonales , Masculino , Ratones , Neuronas/metabolismo , Receptor de Serotonina 5-HT2C/metabolismo , Prueba de Desempeño de Rotación con Aceleración Constante , Transducción de SeñalRESUMEN
Targeted genome editing via engineered nucleases is an exciting area of biomedical research and holds potential for clinical applications. Despite rapid advances in the field, in vivo targeted transgene integration is still infeasible because current tools are inefficient, especially for non-dividing cells, which compose most adult tissues. This poses a barrier for uncovering fundamental biological principles and developing treatments for a broad range of genetic disorders. Based on clustered regularly interspaced short palindromic repeat/Cas9 (CRISPR/Cas9) technology, here we devise a homology-independent targeted integration (HITI) strategy, which allows for robust DNA knock-in in both dividing and non-dividing cells in vitro and, more importantly, in vivo (for example, in neurons of postnatal mammals). As a proof of concept of its therapeutic potential, we demonstrate the efficacy of HITI in improving visual function using a rat model of the retinal degeneration condition retinitis pigmentosa. The HITI method presented here establishes new avenues for basic research and targeted gene therapies.
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Sistemas CRISPR-Cas/genética , Edición Génica/métodos , Marcación de Gen/métodos , Genoma/genética , Retinitis Pigmentosa/genética , Retinitis Pigmentosa/terapia , Animales , División Celular , Modelos Animales de Enfermedad , Técnicas de Sustitución del Gen , Terapia Genética/métodos , Neuronas/citología , Neuronas/metabolismo , Ratas , Homología de SecuenciaRESUMEN
Circadian rhythms are controlled by a system of negative and positive genetic feedback loops composed of clock genes. Although many genes have been implicated in these feedback loops, it is unclear whether our current list of clock genes is exhaustive. We have recently identified Chrono as a robustly cycling transcript through genome-wide profiling of BMAL1 binding on the E-box. Here, we explore the role of Chrono in cellular timekeeping. Remarkably, endogenous CHRONO occupancy around E-boxes shows a circadian oscillation antiphasic to BMAL1. Overexpression of Chrono leads to suppression of BMAL1-CLOCK activity in a histone deacetylase (HDAC) -dependent manner. In vivo loss-of-function studies of Chrono including Avp neuron-specific knockout (KO) mice display a longer circadian period of locomotor activity. Chrono KO also alters the expression of core clock genes and impairs the response of the circadian clock to stress. CHRONO forms a complex with the glucocorticoid receptor and mediates glucocorticoid response. Our comprehensive study spotlights a previously unrecognized clock component of an unsuspected negative circadian feedback loop that is independent of another negative regulator, Cry2, and that integrates behavioral stress and epigenetic control for efficient metabolic integration of the clock.
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Factores de Transcripción ARNTL/metabolismo , Relojes Circadianos/fisiología , Péptidos y Proteínas de Señalización del Ritmo Circadiano/metabolismo , Criptocromos/metabolismo , Proteínas Represoras/metabolismo , Células 3T3 , Secuencia de Aminoácidos , Animales , Células COS , Línea Celular , Chlorocebus aethiops , Relojes Circadianos/genética , Ritmo Circadiano/genética , Ritmo Circadiano/fisiología , Péptidos y Proteínas de Señalización del Ritmo Circadiano/biosíntesis , Péptidos y Proteínas de Señalización del Ritmo Circadiano/genética , Criptocromos/genética , Histona Desacetilasas/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Datos de Secuencia Molecular , Receptores de Glucocorticoides/metabolismo , Proteínas Represoras/biosíntesis , Proteínas Represoras/genética , Alineación de Secuencia , Transcripción Genética/genéticaRESUMEN
Defect in the SMN1 gene causes spinal muscular atrophy (SMA), which shows loss of motor neurons, muscle weakness and atrophy. While current treatment strategies, including small molecules or viral vectors, have shown promise in improving motor function and survival, achieving a definitive and long-term correction of SMA's endogenous mutations and phenotypes remains highly challenging. We have previously developed a CRISPR-Cas9 based homology-independent targeted integration (HITI) strategy, enabling unidirectional DNA knock-in in both dividing and non-dividing cells in vivo. In this study, we demonstrated its utility by correcting an SMA mutation in mice. When combined with Smn1 cDNA supplementation, it exhibited long-term therapeutic benefits in SMA mice. Our observations may provide new avenues for the long-term and efficient treatment of inherited diseases.
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Sistemas CRISPR-Cas , Edición Génica , Terapia Genética , Atrofia Muscular Espinal , Proteína 1 para la Supervivencia de la Neurona Motora , Atrofia Muscular Espinal/terapia , Atrofia Muscular Espinal/genética , Animales , Edición Génica/métodos , Proteína 1 para la Supervivencia de la Neurona Motora/genética , Ratones , Terapia Genética/métodos , Modelos Animales de Enfermedad , Humanos , Neuronas Motoras/metabolismo , Neuronas Motoras/patología , Mutación , Masculino , FemeninoRESUMEN
Tissue regeneration following an injury requires dynamic cell-state transitions that allow for establishing the cell identities required for the restoration of tissue homeostasis and function. Here, we present a biochemical intervention that induces an intermediate cell state mirroring a transition identified during normal differentiation of myoblasts and other multipotent and pluripotent cells to mature cells. When applied in somatic differentiated cells, the intervention, composed of one-carbon metabolites, reduces some dedifferentiation markers without losing the lineage identity, thus inducing limited reprogramming into a more flexible cell state. Moreover, the intervention enabled accelerated repair after muscle injury in young and aged mice. Overall, our study uncovers a conserved biochemical transitional phase that enhances cellular plasticity in vivo and hints at potential and scalable biochemical interventions of use in regenerative medicine and rejuvenation interventions that may be more tractable than genetic ones.
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Músculos , Mioblastos , Ratones , Animales , Diferenciación Celular , Mioblastos/metabolismoRESUMEN
Circadian oscillators in the suprachiasmatic nucleus (SCN) collectively orchestrate 24 h rhythms in the body while also coding for seasonal rhythms. Although synchronization is required among SCN oscillators to provide robustness for regular timekeeping (Herzog et al., 2004), heterogeneity of period and phase distributions is needed to accommodate seasonal variations in light duration (Pittendrigh and Daan, 1976b). In the mouse SCN, the heterogeneous phase distribution has been recently found in the cycling of clock genes Period 1 and Period 2 (Per1, Per2) and has been shown to reorganize by relative day lengths (Inagaki et al., 2007). However, it is not yet clearly understood what underlies the spatial patterning of Per1 and Per2 expression (Yamaguchi et al., 2003; Foley et al., 2011) and its plasticity. We found that the period of the oscillation in Bmal1 expression, a positive-feedback component of the circadian clock, preserves the behavioral circadian period under culture and drives clustered oscillations in the mouse SCN. Pharmacological and physical isolations of SCN subregions indicate that the period of Bmal1 oscillation is subregion specific and is preserved during culture. Together with computer simulations, we show that either the intercellular coupling does not strongly influence the Bmal1 oscillation or the nature of the coupling is more complex than previously assumed. Furthermore, we have found that the region-specific periods are modulated by the light conditions that an animal is exposed to. Based on these, we suggest that the period forms the basis of seasonal coding in the SCN.
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Factores de Transcripción ARNTL/metabolismo , Relojes Biológicos/fisiología , Ritmo Circadiano/genética , Fotoperiodo , Núcleo Supraquiasmático/metabolismo , Factores de Transcripción ARNTL/genética , Potenciales de Acción/efectos de los fármacos , Potenciales de Acción/genética , Animales , Relojes Biológicos/efectos de los fármacos , Relojes Biológicos/genética , Mapeo Encefálico , Ritmo Circadiano/efectos de los fármacos , Análisis por Conglomerados , Antagonistas del GABA/farmacología , Regulación de la Expresión Génica/genética , Proteínas Luminiscentes/genética , Proteínas Luminiscentes/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Modelos Neurológicos , Actividad Motora/genética , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Dinámicas no Lineales , Técnicas de Cultivo de Órganos , Proteínas Circadianas Period/genética , Proteínas Circadianas Period/metabolismo , Piridazinas/farmacología , Bloqueadores de los Canales de Sodio/farmacología , Programas Informáticos , Estadística como Asunto , Núcleo Supraquiasmático/citología , Tetrodotoxina/farmacologíaRESUMEN
It is widely believed that cellular senescence plays a critical role in both aging and cancer, and that senescence is a fundamental, permanent growth arrest that somatic cells cannot avoid. Here we show that Myc plays an important role in self-renewal of esophageal epithelial cells, contributing to their resistance to cellular senescence. Myc is homogeneously expressed in basal cells of the esophageal epithelium and Myc positively regulates their self-renewal by maintaining their undifferentiated state. Indeed, Myc knockout induced a loss of the undifferentiated state of esophageal epithelial cells resulting in cellular senescence while forced MYC expression promoted oncogenic cell proliferation. A superoxide scavenger counteracted Myc knockout-induced senescence, therefore suggesting that a mitochondrial superoxide takes part in inducing senescence. Taken together, these analyses reveal extremely low levels of cellular senescence and senescence-associated phenotypes in the esophageal epithelium, as well as a critical role for Myc in self-renewal of basal cells in this organ. This provides new avenues for studying and understanding the links between stemness and resistance to cellular senescence.
RESUMEN
Mammals have limited regenerative capacity, whereas some vertebrates, like fish and salamanders, are able to regenerate their organs efficiently. The regeneration in these species depends on cell dedifferentiation followed by proliferation. We generate a mouse model that enables the inducible expression of the four Yamanaka factors (Oct-3/4, Sox2, Klf4, and c-Myc, or 4F) specifically in hepatocytes. Transient in vivo 4F expression induces partial reprogramming of adult hepatocytes to a progenitor state and concomitantly increases cell proliferation. This is indicated by reduced expression of differentiated hepatic-lineage markers, an increase in markers of proliferation and chromatin modifiers, global changes in DNA accessibility, and an acquisition of liver stem and progenitor cell markers. Functionally, short-term expression of 4F enhances liver regenerative capacity through topoisomerase2-mediated partial reprogramming. Our results reveal that liver-specific 4F expression in vivo induces cellular plasticity and counteracts liver failure, suggesting that partial reprogramming may represent an avenue for enhancing tissue regeneration.
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Reprogramación Celular , Hígado , Animales , Desdiferenciación Celular , Hepatocitos/metabolismo , Hígado/metabolismo , Regeneración Hepática , Mamíferos , RatonesRESUMEN
Autism spectrum disorder (ASD) is a neurodevelopmental disorder. Several genetic causes of ASD have been identified and this has enabled researchers to construct mouse models. Mouse behavioral tests reveal impaired social interaction and communication, as well as increased repetitive behavior and behavioral inflexibility in these mice, which correspond to core behavioral deficits observed in individuals with ASD. However, the connection between these behavioral abnormalities and the underlying dysregulation in neuronal circuits and synaptic function is poorly understood. Moreover, different components of the ASD phenotype may be linked to dysfunction in different brain regions, making it even more challenging to chart the pathophysiological mechanisms involved in ASD. Here we summarize the research on mouse models of ASD and their contribution to understanding pathophysiological mechanisms. Specifically, we emphasize abnormal serotonin production and regulation, as well as the disruption in circadian rhythms and sleep that are observed in a subset of ASD, and propose that spatiotemporal disturbances in brainstem development may be a primary cause of ASD that propagates towards the cerebral cortex.
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Trastorno del Espectro Autista/fisiopatología , Trastorno Autístico/fisiopatología , Encéfalo/fisiopatología , Ritmo Circadiano/fisiología , Animales , Trastorno Autístico/genética , Humanos , Fenotipo , Conducta SocialRESUMEN
Identification of the precise molecular pathways involved in oncogene-induced transformation may help us gain a better understanding of tumor initiation and promotion. Here, we demonstrate that SOX2+ foregut epithelial cells are prone to oncogenic transformation upon mutagenic insults, such as KrasG12D and p53 deletion. GFP-based lineage-tracing experiments indicate that SOX2+ cells are the cells-of-origin of esophagus and stomach hyperplasia. Our observations indicate distinct roles for oncogenic KRAS mutation and P53 deletion. p53 homozygous deletion is required for the acquisition of an invasive potential, and KrasG12D expression, but not p53 deletion, suffices for tumor formation. Global gene expression analysis reveals secreting factors upregulated in the hyperplasia induced by oncogenic KRAS and highlights a crucial role for the CXCR2 pathway in driving hyperplasia. Collectively, the array of genetic models presented here demonstrate that stratified epithelial cells are susceptible to oncogenic insults, which may lead to a better understanding of tumor initiation and aid in the design of new cancer therapeutics.
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Neoplasias Esofágicas/metabolismo , Mutación , Receptores de Interleucina-8B/metabolismo , Factores de Transcripción SOXB1/metabolismo , Animales , Proliferación Celular , Neoplasias Esofágicas/patología , Femenino , Masculino , Ratones , Ratones Mutantes , Transducción de Señal , Células Tumorales CultivadasRESUMEN
In vivo genome editing represents a powerful strategy for both understanding basic biology and treating inherited diseases. However, it remains a challenge to develop universal and efficient in vivo genome-editing tools for tissues that comprise diverse cell types in either a dividing or non-dividing state. Here, we describe a versatile in vivo gene knock-in methodology that enables the targeting of a broad range of mutations and cell types through the insertion of a minigene at an intron of the target gene locus using an intracellularly linearized single homology arm donor. As a proof-of-concept, we focused on a mouse model of premature-aging caused by a dominant point mutation, which is difficult to repair using existing in vivo genome-editing tools. Systemic treatment using our new method ameliorated aging-associated phenotypes and extended animal lifespan, thus highlighting the potential of this methodology for a broad range of in vivo genome-editing applications.
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Edición Génica/métodos , Animales , Sistemas CRISPR-Cas/genética , Reparación del ADN , Dependovirus/genética , Factor de Transcripción GATA3/genética , Técnicas de Sustitución del Gen , Terapia Genética/métodos , Vectores Genéticos/metabolismo , Células Madre Embrionarias Humanas , Humanos , Intrones , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos ICR , Neuronas/citología , Neuronas/metabolismo , ARN Guía de Kinetoplastida/metabolismo , Ratas , Tubulina (Proteína)/genéticaRESUMEN
Circadian rhythms are a critical part of the body's homeostatic mechanisms. These rhythms repeat with a cycle-length of approximately 24 h and are generated by a transcriptional-translational feedback loop. These rhythms are critical for proper behavioral, physiological, and molecular functions. CHRONO, a novel circadian clock gene, forms a complex with other clock proteins and modulates the circadian machinery. CHRONO also interacts with histone deacetylase (HDAC) to modulate the epigenetic status of the transcriptional regulation. Chrono knockout mice display a longer period of circadian behavior and an elevated stress response. This paper reviews the molecular function of CHRONO with a focus on epigenetic regulation and speculates on the possible function of CHRONO in physiological processes. Key messages Chrono is a circadian clock gene whose transcription exhibits a robust circadian oscillation. CHRONO is a repressor of circadian transcriptional/translational feedback loops. CHRONO may function to link epigenetic control mechanisms to stress responses.
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Proteínas CLOCK/genética , Proteínas CLOCK/metabolismo , Péptidos y Proteínas de Señalización del Ritmo Circadiano/genética , Péptidos y Proteínas de Señalización del Ritmo Circadiano/metabolismo , Histona Desacetilasas/metabolismo , Estrés Fisiológico , Animales , Ritmo Circadiano , Epigénesis Genética , Regulación de la Expresión Génica , Histonas/metabolismo , HumanosRESUMEN
The circadian oscillation of clock gene expression in mammals is based on the interconnected transcriptional/translational feedback loops of Period (Per) and Bmal1. The Per feedback loop initiates transcription through direct binding of the BMAL1-CLOCK (NPAS2) heterodimer to the E-box of the Per2 promoter region. Negative feedback of PER protein on this promoter subsequently represses transcription. Other circadian transcription regulators, particularly E4BP4 and DEC2, regulate the amplitude and phase of Per2 expression rhythms. Moreover, a direct repeat of E-box-like (EE) elements in the Per2 promoter is required for its cell-autonomous circadian rhythm. However, the detailed mechanism for repression of the two core sequences of the EE element in the Per2 promoter region is unknown. Here, we show that E4BP4 binds to the Per2 EE element with DEC2 to repress transcription and identify the DEC2-E4BP4 heterodimer as a key repressor of the tightly interlocked Per2 feedback loop in the mammalian circadian oscillator. Our results suggest an additional modulatory mechanism for tuning of the phase of cell-autonomous Per2 gene expression cycling.
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Cartílago Articular/efectos de los fármacos , Condrocitos/efectos de los fármacos , Glucuronidasa/uso terapéutico , Osteoartritis de la Rodilla/tratamiento farmacológico , Receptor Tipo II de Factor de Crecimiento Transformador beta/uso terapéutico , Animales , Cartílago Articular/patología , Técnicas de Cultivo de Célula , Condrocitos/patología , Humanos , Proteínas Klotho , Osteoartritis de la Rodilla/inducido químicamente , Papaína , Ratas , Proteínas Recombinantes/uso terapéuticoRESUMEN
The scale-invariant and intermittent dynamics of animal behavior are attracting scientific interest. Recent findings concerning the statistical laws of behavioral organization shared between healthy humans and wild-type mice (WT) and their alterations in human depression patients and circadian clock gene (Period 2; Per2) mutant mice indicate that clock genes play functional roles in intermittent, ultradian locomotor dynamics. They also claim the clinical and biological importance of the laws as objective biobehavioral measures or endophenotypes for psychiatric disorders. In this study, to elucidate the roles of breakdown of the broader circadian regulatory circuit in intermittent behavioral dynamics, we studied the statistical properties and rhythmicity of locomotor activity in Per2 mutants and mice deficient in other clock genes (Bmal1, Clock). We performed wavelet analysis to examine circadian and ultradian rhythms and estimated the cumulative distributions of resting period durations during which locomotor activity levels are continuously lower than a predefined threshold value. The wavelet analysis revealed significant amplification of ultradian rhythms in the BMAL1-deficient mice, and instability in the Per2 mutants. The resting period distributions followed a power-law form in all mice. While the distributions for the BMAL1-deficient and Clock mutant mice were almost identical to those for the WT mice, with no significant differences in their parameter (power-law scaling exponent), only the Per2 mutant mice showed consistently and significantly lower values of the scaling exponent, indicating the increased intermittency in ultradian locomotor dynamics. Furthermore, based on a stochastic priority queuing model, we explained the power-law nature of resting period distributions, as well as its alterations shared with human depressive patients and Per2 mutant mice. Our findings lead to the development of a novel mathematical model for abnormal behaviors in psychiatric disorders.
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Péptidos y Proteínas de Señalización del Ritmo Circadiano/deficiencia , Péptidos y Proteínas de Señalización del Ritmo Circadiano/genética , Locomoción/genética , Locomoción/fisiología , Modelos Estadísticos , Animales , Conducta Animal/fisiología , Ritmo Circadiano/genética , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Modelos Biológicos , Fenotipo , Análisis de OndículasRESUMEN
Autism spectrum disorders (ASDs) have garnered significant attention as an important grouping of developmental brain disorders. Recent genomic studies have revealed that inherited or de novo copy number variations (CNVs) are significantly involved in the pathophysiology of ASDs. In a previous report from our laboratory, we generated mice with CNVs as a model of ASDs, with a duplicated mouse chromosome 7C that is orthologous to human chromosome 15q11-13. Behavioral analyses revealed paternally duplicated (patDp/+) mice displayed abnormal behaviors resembling the symptoms of ASDs. In the present study, we extended these findings by performing various behavioral tests with C57BL/6J patDp/+ mice, and comprehensively measuring brain monoamine levels with ex vivo high performance liquid chromatography. Compared with wild-type controls, patDp/+ mice exhibited decreased locomotor and exploratory activities in the open field test, Y-maze test, and fear-conditioning test. Furthermore, their decreased activity levels overcame increased appetite induced by 24 hours of food deprivation in the novelty suppressed feeding test. Serotonin levels in several brain regions of adult patDp/+ mice were lower than those of wild-type control, with no concurrent changes in brain levels of dopamine or norepinephrine. Moreover, analysis of monoamines in postnatal developmental stages demonstrated reduced brain levels of serotonin in young patDp/+ mice. These findings suggest that a disrupted brain serotonergic system, especially during postnatal development, may generate the phenotypes of patDp/+ mice.