RESUMO
Genes implicated in neuropsychiatric disorders are active in human fetal brain, yet difficult to study in a longitudinal fashion. We demonstrate that organoids from human pluripotent cells model cerebral cortical development on the molecular level before 16 weeks postconception. A multiomics analysis revealed differentially active genes and enhancers, with the greatest changes occurring at the transition from stem cells to progenitors. Networks of converging gene and enhancer modules were assembled into six and four global patterns of expression and activity across time. A pattern with progressive down-regulation was enriched with human-gained enhancers, suggesting their importance in early human brain development. A few convergent gene and enhancer modules were enriched in autism-associated genes and genomic variants in autistic children. The organoid model helps identify functional elements that may drive disease onset.
Assuntos
Córtex Cerebral/embriologia , Epigênese Genética , Regulação da Expressão Gênica no Desenvolvimento , Modelos Neurológicos , Neurogênese/genética , Organoides/embriologia , Elementos Facilitadores Genéticos , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , TranscriptomaRESUMO
To broaden our understanding of human neurodevelopment, we profiled transcriptomic and epigenomic landscapes across brain regions and/or cell types for the entire span of prenatal and postnatal development. Integrative analysis revealed temporal, regional, sex, and cell type-specific dynamics. We observed a global transcriptomic cup-shaped pattern, characterized by a late fetal transition associated with sharply decreased regional differences and changes in cellular composition and maturation, followed by a reversal in childhood-adolescence, and accompanied by epigenomic reorganizations. Analysis of gene coexpression modules revealed relationships with epigenomic regulation and neurodevelopmental processes. Genes with genetic associations to brain-based traits and neuropsychiatric disorders (including MEF2C, SATB2, SOX5, TCF4, and TSHZ3) converged in a small number of modules and distinct cell types, revealing insights into neurodevelopment and the genomic basis of neuropsychiatric risks.
Assuntos
Encéfalo/embriologia , Regulação da Expressão Gênica no Desenvolvimento , Transtornos Mentais/genética , Doenças do Sistema Nervoso/genética , Neurogênese/genética , Encéfalo/crescimento & desenvolvimento , Epigênese Genética , Epigenômica , Redes Reguladoras de Genes , Humanos , Análise de Célula Única , TranscriptomaRESUMO
Brain development and function depend on the precise regulation of gene expression. However, our understanding of the complexity and dynamics of the transcriptome of the human brain is incomplete. Here we report the generation and analysis of exon-level transcriptome and associated genotyping data, representing males and females of different ethnicities, from multiple brain regions and neocortical areas of developing and adult post-mortem human brains. We found that 86 per cent of the genes analysed were expressed, and that 90 per cent of these were differentially regulated at the whole-transcript or exon level across brain regions and/or time. The majority of these spatio-temporal differences were detected before birth, with subsequent increases in the similarity among regional transcriptomes. The transcriptome is organized into distinct co-expression networks, and shows sex-biased gene expression and exon usage. We also profiled trajectories of genes associated with neurobiological categories and diseases, and identified associations between single nucleotide polymorphisms and gene expression. This study provides a comprehensive data set on the human brain transcriptome and insights into the transcriptional foundations of human neurodevelopment.
Assuntos
Envelhecimento/genética , Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento/genética , Transcriptoma/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/embriologia , Criança , Pré-Escolar , Éxons/genética , Feminino , Feto/metabolismo , Redes Reguladoras de Genes/genética , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Controle de Qualidade , Locos de Características Quantitativas/genética , Caracteres Sexuais , Fatores de Tempo , Adulto JovemRESUMO
The corticospinal (CS) tract is involved in controlling discrete voluntary skilled movements in mammals. The CS tract arises exclusively from layer (L) 5 projection neurons of the cerebral cortex, and its formation requires L5 activity of Fezf2 (Fezl, Zfp312). How this L5-specific pattern of Fezf2 expression and CS axonal connectivity is established with such remarkable fidelity had remained elusive. Here we show that the transcription factor TBR1 directly binds the Fezf2 locus and represses its activity in L6 corticothalamic projection neurons to restrict the origin of the CS tract to L5. In Tbr1 null mutants, CS axons ectopically originate from L6 neurons in a Fezf2-dependent manner. Consistently, misexpression of Tbr1 in L5 CS neurons suppresses Fezf2 expression and effectively abolishes the CS tract. Taken together, our findings show that TBR1 is a direct transcriptional repressor of Fezf2 and a negative regulator of CS tract formation that restricts the laminar origin of CS axons specifically to L5.
