RESUMEN
The human brain is a complex organ comprised of distinct cell types, and the contribution of the 3D genome to lineage specific gene expression remains poorly understood. To decipher cell type specific genome architecture, and characterize fine scale changes in the chromatin interactome across neural development, we compared the 3D genome of the human fetal cortical plate to that of neurons and glia isolated from the adult prefrontal cortex. We found that neurons have weaker genome compartmentalization compared to glia, but stronger TADs, which emerge during fetal development. Furthermore, relative to glia, the neuronal genome shifts more strongly towards repressive compartments. Neurons have differential TAD boundaries that are proximal to active promoters involved in neurodevelopmental processes. CRISPRi on CNTNAP2 in hIPSC-derived neurons reveals that transcriptional inactivation correlates with loss of insulation at the differential boundary. Finally, re-wiring of chromatin loops during neural development is associated with transcriptional and functional changes. Importantly, differential loops in the fetal cortex are associated with autism GWAS loci, suggesting a neuropsychiatric disease mechanism affecting the chromatin interactome. Furthermore, neural development involves gaining enhancer-promoter loops that upregulate genes that control synaptic activity. Altogether, our study provides multi-scale insights on the 3D genome in the human brain.
Asunto(s)
Encéfalo , Cromatina , Neurogénesis , Adulto , Humanos , Encéfalo/crecimiento & desarrollo , Encéfalo/metabolismo , Cromatina/metabolismo , Genoma , NeuronasRESUMEN
In part
RESUMEN
We analyzed the influence of the transcription factor DeltaFosB on learned helplessness, an animal model of affective disorder wherein a subset of mice exposed to inescapable stress (IS) develop a deficit in escape behavior. Repeated IS induces DeltaFosB in the ventrolateral periaqueductal gray (vlPAG), and levels of the protein are highly predictive of an individual's subsequent behavorial deficit-with the strongest DeltaFosB induction observed in the most resilient animals. Induction of DeltaFosB by IS predominates in substance P-positive neurons in the vlPAG, and the substance P gene, a direct target for DeltaFosB, is downregulated upon DeltaFosB induction. Local overexpression of DeltaFosB in the vlPAG using viral-mediated gene transfer dramatically reduces depression-like behaviors and inhibits stress-induced release of substance P. These results indicate that IS-induced accumulation of DeltaFosB in the vlPAG desensitizes substance P neurons enriched in this area and opposes behavioral despair by promoting active defense responses.
Asunto(s)
Reacción de Fuga/fisiología , Desamparo Adquirido , Sustancia Gris Periacueductal/metabolismo , Proteínas Proto-Oncogénicas c-fos/metabolismo , Estrés Psicológico/metabolismo , Adaptación Fisiológica , Adaptación Psicológica/fisiología , Análisis de Varianza , Animales , Regulación de la Expresión Génica/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Neuronas/metabolismo , Núcleo Accumbens/metabolismo , Sustancia Gris Periacueductal/citología , Ratas , Ratas Sprague-Dawley , Sustancia P/metabolismoRESUMEN
Previous work has identified alterations in histone acetylation in animal models of drug addiction and depression. However, the mechanisms which integrate drugs and stress with changes in chromatin structure remain unclear. Here, we identify the activity-dependent class II histone deacetylase, HDAC5, as a central integrator of these stimuli with changes in chromatin structure and gene expression. Chronic, but not acute, exposure to cocaine or stress decreases HDAC5 function in the nucleus accumbens (NAc), a major brain reward region, which allows for increased histone acetylation and transcription of HDAC5 target genes. This regulation is behaviorally important, as loss of HDAC5 causes hypersensitive responses to chronic, not acute, cocaine or stress. These findings suggest that proper balance of histone acetylation is a crucial factor in the saliency of a given stimulus and that disruption of this balance is involved in the transition from an acute adaptive response to a chronic psychiatric illness.
Asunto(s)
Trastornos Relacionados con Cocaína/enzimología , Trastornos Relacionados con Cocaína/genética , Epigénesis Genética/genética , Histona Desacetilasas/genética , Estrés Psicológico/enzimología , Estrés Psicológico/genética , Acetilación/efectos de los fármacos , Adaptación Fisiológica/efectos de los fármacos , Adaptación Fisiológica/genética , Animales , Cromatina/efectos de los fármacos , Cromatina/genética , Enfermedad Crónica , Cocaína/farmacología , Trastornos Relacionados con Cocaína/fisiopatología , Modelos Animales de Enfermedad , Inhibidores de Captación de Dopamina/farmacología , Emociones/efectos de los fármacos , Emociones/fisiología , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Regulación Enzimológica de la Expresión Génica/genética , Histonas/metabolismo , Ratones , Ratones Endogámicos C57BL , Núcleo Accumbens/efectos de los fármacos , Núcleo Accumbens/enzimología , Núcleo Accumbens/fisiopatología , Recompensa , Estrés Psicológico/fisiopatologíaRESUMEN
To better understand the molecular mechanisms of depression and antidepressant action, we administered chronic social defeat stress followed by chronic imipramine (a tricyclic antidepressant) to mice and studied adaptations at the levels of gene expression and chromatin remodeling of five brain-derived neurotrophic factor (Bdnf) splice variant mRNAs (I-V) and their unique promoters in the hippocampus. Defeat stress induced lasting downregulation of Bdnf transcripts III and IV and robustly increased repressive histone methylation at their corresponding promoters. Chronic imipramine reversed this downregulation and increased histone acetylation at these promoters. This hyperacetylation by chronic imipramine was associated with a selective downregulation of histone deacetylase (Hdac) 5. Furthermore, viral-mediated HDAC5 overexpression in the hippocampus blocked imipramine's ability to reverse depression-like behavior. These experiments underscore an important role for histone remodeling in the pathophysiology and treatment of depression and highlight the therapeutic potential for histone methylation and deacetylation inhibitors in depression.
Asunto(s)
Antidepresivos/farmacología , Cromatina/metabolismo , Depresión/fisiopatología , Hipocampo/efectos de los fármacos , Hipocampo/fisiología , Acetilación , Animales , Antidepresivos/uso terapéutico , Conducta Animal/fisiología , Factor Neurotrófico Derivado del Encéfalo/genética , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Depresión/tratamiento farmacológico , Modelos Animales de Enfermedad , Hipocampo/citología , Histonas/metabolismo , Imipramina/farmacología , Imipramina/uso terapéutico , Masculino , Metilación , Ratones , Ratones Endogámicos C57BL , Estrés Psicológico/metabolismoRESUMEN
Given that cocaine induces neuroadaptations through regulation of gene expression, we investigated whether chromatin remodeling at specific gene promoters may be a key mechanism. We show that cocaine induces specific histone modifications at different gene promoters in striatum, a major neural substrate for cocaine's behavioral effects. At the cFos promoter, H4 hyperacetylation is seen within 30 min of a single cocaine injection, whereas no histone modifications were seen with chronic cocaine, consistent with cocaine's ability to induce cFos acutely, but not chronically. In contrast, at the BDNF and Cdk5 promoters, genes that are induced by chronic, but not acute, cocaine, H3 hyperacetylation was observed with chronic cocaine only. DeltaFosB, a cocaine-induced transcription factor, appears to mediate this regulation of the Cdk5 gene. Furthermore, modulating histone deacetylase activity alters locomotor and rewarding responses to cocaine. Thus, chromatin remodeling is an important regulatory mechanism underlying cocaine-induced neural and behavioral plasticity.
Asunto(s)
Ensamble y Desensamble de Cromatina/fisiología , Cocaína/administración & dosificación , Cuerpo Estriado/efectos de los fármacos , Inhibidores de Captación de Dopamina/administración & dosificación , Plasticidad Neuronal/efectos de los fármacos , Acetilación , Animales , Conducta Animal/efectos de los fármacos , Factor Neurotrófico Derivado del Encéfalo/genética , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Butiratos/farmacología , Ensamble y Desensamble de Cromatina/efectos de los fármacos , Condicionamiento Operante/efectos de los fármacos , Cuerpo Estriado/fisiología , Quinasa 5 Dependiente de la Ciclina/genética , Quinasa 5 Dependiente de la Ciclina/metabolismo , Esquema de Medicación , Interacciones Farmacológicas , Inhibidores Enzimáticos/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Técnicas de Transferencia de Gen/psicología , Histona Desacetilasas/metabolismo , Histonas/clasificación , Histonas/metabolismo , Inmunohistoquímica/métodos , Inmunoprecipitación/métodos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Actividad Motora/efectos de los fármacos , Células PC12/metabolismo , Regiones Promotoras Genéticas/fisiología , Subunidades de Proteína , Proteínas Proto-Oncogénicas c-fos/genética , ARN Mensajero/biosíntesis , Ratas , Ratas Sprague-Dawley , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Factores de TiempoRESUMEN
The mechanism of action of electroconvulsive seizures (ECS), one of the most effective treatments of major depression, may involve the regulation of gene expression. Chromatin remodeling at gene promoter regions is increasingly recognized as a key control point of gene expression and may, therefore, partly mediate acute and chronic effects of ECS on gene activity. Here, we assayed how posttranslational modifications of histones, a major form of chromatin remodeling, are altered at several gene promoters in rat hippocampus at 30 min, 2 hr, and 24 hr after acute or repeated ECS. We performed chromatin immunoprecipitation assays to measure levels of histone H3 and H4 acetylation and phosphoacetylation at the promoters of the c-fos, BDNF, and CREB (cAMP response element-binding protein) genes, the expression of which is altered by ECS. We found that, with few exceptions, levels of H4 acetylation correlated with mRNA levels for c-fos, BDNF, and CREB throughout the acute and chronic time course study, whereas acetylation and phosphoacetylation of H3 were detected more selectively. Our findings suggest that the chronic downregulation of c-fos transcription, observed in this study, may be achieved at the level of H4 acetylation, whereas chronic upregulation of BDNF transcription may be sustained via control of H3 acetylation, selectively at the BDNF P3 and P4 promoters. These data provide the first in vivo demonstration of the involvement of chromatin remodeling in ECS-induced regulation of gene expression in the brain and will help in understanding the mechanisms underlying the efficacy of ECS in the treatment of depression.
Asunto(s)
Hipocampo/metabolismo , Histonas/metabolismo , Acetilación , Animales , Factor Neurotrófico Derivado del Encéfalo/biosíntesis , Factor Neurotrófico Derivado del Encéfalo/genética , Cromatina/metabolismo , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/biosíntesis , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/genética , Electrochoque , Inmunoprecipitación , Masculino , Reacción en Cadena de la Polimerasa , Regiones Promotoras Genéticas , Procesamiento Proteico-Postraduccional , Proteínas Proto-Oncogénicas c-fos/biosíntesis , Proteínas Proto-Oncogénicas c-fos/genética , ARN Mensajero/biosíntesis , Ratas , Ratas Sprague-Dawley , Factores de TiempoRESUMEN
Many neurological and most psychiatric disorders are not due to mutations in a single gene; rather, they involve molecular disturbances entailing multiple genes and signals that control their expression. Recent research has demonstrated that complex 'epigenetic' mechanisms, which regulate gene activity without altering the DNA code, have long-lasting effects within mature neurons. This review summarizes recent evidence for the existence of sustained epigenetic mechanisms of gene regulation in neurons that have been implicated in the regulation of complex behaviour, including abnormalities in several psychiatric disorders such as depression, drug addiction and schizophrenia.
Asunto(s)
Epigénesis Genética/fisiología , Regulación de la Expresión Génica/fisiología , Trastornos Mentales/genética , Trastornos Mentales/fisiopatología , Animales , Encéfalo/patología , Humanos , Trastornos Mentales/patología , Modelos Biológicos , Neuronas/fisiologíaRESUMEN
Mice experiencing repeated aggression develop a long-lasting aversion to social contact, which can be normalized by chronic, but not acute, administration of antidepressant. Using viral-mediated, mesolimbic dopamine pathway-specific knockdown of brain-derived neurotrophic factor (BDNF), we showed that BDNF is required for the development of this experience-dependent social aversion. Gene profiling in the nucleus accumbens indicates that local knockdown of BDNF obliterates most of the effects of repeated aggression on gene expression within this circuit, with similar effects being produced by chronic treatment with antidepressant. These results establish an essential role for BDNF in mediating long-term neural and behavioral plasticity in response to aversive social experiences.