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1.
Cell ; 186(26): 5766-5783.e25, 2023 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-38134874

RESUMO

The enhanced cognitive abilities characterizing the human species result from specialized features of neurons and circuits. Here, we report that the hominid-specific gene LRRC37B encodes a receptor expressed in human cortical pyramidal neurons (CPNs) and selectively localized to the axon initial segment (AIS), the subcellular compartment triggering action potentials. Ectopic expression of LRRC37B in mouse CPNs in vivo leads to reduced intrinsic excitability, a distinctive feature of some classes of human CPNs. Molecularly, LRRC37B binds to the secreted ligand FGF13A and to the voltage-gated sodium channel (Nav) ß-subunit SCN1B. LRRC37B concentrates inhibitory effects of FGF13A on Nav channel function, thereby reducing excitability, specifically at the AIS level. Electrophysiological recordings in adult human cortical slices reveal lower neuronal excitability in human CPNs expressing LRRC37B. LRRC37B thus acts as a species-specific modifier of human neuron excitability, linking human genome and cell evolution, with important implications for human brain function and diseases.


Assuntos
Neurônios , Células Piramidais , Canais de Sódio Disparados por Voltagem , Animais , Humanos , Camundongos , Potenciais de Ação/fisiologia , Axônios/metabolismo , Neurônios/metabolismo , Canais de Sódio Disparados por Voltagem/genética , Canais de Sódio Disparados por Voltagem/metabolismo
2.
Neuron ; 111(1): 65-80.e6, 2023 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-36334595

RESUMO

The primary cilium is a central signaling component during embryonic development. Here we focus on CROCCP2, a hominid-specific gene duplicate from ciliary rootlet coiled coil (CROCC), also known as rootletin, that encodes the major component of the ciliary rootlet. We find that CROCCP2 is highly expressed in the human fetal brain and not in other primate species. CROCCP2 gain of function in the mouse embryonic cortex and human cortical cells and organoids results in decreased ciliogenesis and increased cortical progenitor amplification, particularly basal progenitors. CROCCP2 decreases ciliary dynamics by inhibition of the IFT20 ciliary trafficking protein, which then impacts neurogenesis through increased mTOR signaling. Loss of function of CROCCP2 in human cortical cells and organoids leads to increased ciliogenesis, decreased mTOR signaling, and impaired basal progenitor amplification. These data identify CROCCP2 as a human-specific modifier of cortical neurogenesis that acts through modulation of ciliary dynamics and mTOR signaling.


Assuntos
Cílios , Transdução de Sinais , Animais , Humanos , Camundongos , Cílios/metabolismo , Citoesqueleto/metabolismo , Neurogênese , Serina-Treonina Quinases TOR/metabolismo
3.
J Clin Invest ; 130(12): 6338-6353, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33164986

RESUMO

Neonatal diabetes is caused by single gene mutations reducing pancreatic ß cell number or impairing ß cell function. Understanding the genetic basis of rare diabetes subtypes highlights fundamental biological processes in ß cells. We identified 6 patients from 5 families with homozygous mutations in the YIPF5 gene, which is involved in trafficking between the endoplasmic reticulum (ER) and the Golgi. All patients had neonatal/early-onset diabetes, severe microcephaly, and epilepsy. YIPF5 is expressed during human brain development, in adult brain and pancreatic islets. We used 3 human ß cell models (YIPF5 silencing in EndoC-ßH1 cells, YIPF5 knockout and mutation knockin in embryonic stem cells, and patient-derived induced pluripotent stem cells) to investigate the mechanism through which YIPF5 loss of function affects ß cells. Loss of YIPF5 function in stem cell-derived islet cells resulted in proinsulin retention in the ER, marked ER stress, and ß cell failure. Partial YIPF5 silencing in EndoC-ßH1 cells and a patient mutation in stem cells increased the ß cell sensitivity to ER stress-induced apoptosis. We report recessive YIPF5 mutations as the genetic cause of a congenital syndrome of microcephaly, epilepsy, and neonatal/early-onset diabetes, highlighting a critical role of YIPF5 in ß cells and neurons. We believe this is the first report of mutations disrupting the ER-to-Golgi trafficking, resulting in diabetes.


Assuntos
Diabetes Mellitus , Estresse do Retículo Endoplasmático/genética , Doenças Genéticas Inatas , Doenças do Recém-Nascido , Microcefalia , Mutação , Proteínas de Transporte Vesicular , Linhagem Celular , Diabetes Mellitus/embriologia , Diabetes Mellitus/genética , Diabetes Mellitus/patologia , Feminino , Doenças Genéticas Inatas/embriologia , Doenças Genéticas Inatas/genética , Doenças Genéticas Inatas/patologia , Células-Tronco Embrionárias Humanas/metabolismo , Células-Tronco Embrionárias Humanas/patologia , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes Induzidas/patologia , Recém-Nascido , Doenças do Recém-Nascido/embriologia , Doenças do Recém-Nascido/genética , Doenças do Recém-Nascido/patologia , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patologia , Masculino , Microcefalia/embriologia , Microcefalia/genética , Microcefalia/patologia , Neurônios/metabolismo , Neurônios/patologia , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismo
4.
Neuron ; 104(5): 972-986.e6, 2019 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-31761708

RESUMO

How neural circuits develop in the human brain has remained almost impossible to study at the neuronal level. Here, we investigate human cortical neuron development, plasticity, and function using a mouse/human chimera model in which xenotransplanted human cortical pyramidal neurons integrate as single cells into the mouse cortex. Combined neuronal tracing, electrophysiology, and in vivo structural and functional imaging of the transplanted cells reveal a coordinated developmental roadmap recapitulating key milestones of human cortical neuron development. The human neurons display a prolonged developmental timeline, indicating the neuron-intrinsic retention of juvenile properties as an important component of human brain neoteny. Following maturation, human neurons in the visual cortex display tuned, decorrelated responses to visual stimuli, like mouse neurons, demonstrating their capacity for physiological synaptic integration in host cortical circuits. These findings provide new insights into human neuronal development and open novel avenues for the study of human neuronal function and disease. VIDEO ABSTRACT.


Assuntos
Neurogênese/fisiologia , Células Piramidais/citologia , Células Piramidais/fisiologia , Células Piramidais/transplante , Animais , Diferenciação Celular/fisiologia , Xenoenxertos , Humanos , Camundongos , Córtex Visual/citologia , Córtex Visual/fisiologia
5.
Neuron ; 103(6): 1096-1108.e4, 2019 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-31353074

RESUMO

During neurogenesis, progenitors switch from self-renewal to differentiation through the interplay of intrinsic and extrinsic cues, but how these are integrated remains poorly understood. Here, we combine whole-genome transcriptional and epigenetic analyses with in vivo functional studies to demonstrate that Bcl6, a transcriptional repressor previously reported to promote cortical neurogenesis, acts as a driver of the neurogenic transition through direct silencing of a selective repertoire of genes belonging to multiple extrinsic pathways promoting self-renewal, most strikingly the Wnt pathway. At the molecular level, Bcl6 represses its targets through Sirt1 recruitment followed by histone deacetylation. Our data identify a molecular logic by which a single cell-intrinsic factor represses multiple extrinsic pathways that favor self-renewal, thereby ensuring robustness of neuronal fate transition.


Assuntos
Autorrenovação Celular/genética , Repressão Epigenética/genética , Histonas/metabolismo , Células-Tronco Neurais/metabolismo , Neurogênese/genética , Proteínas Proto-Oncogênicas c-bcl-6/genética , Sirtuína 1/metabolismo , Animais , Fatores de Crescimento de Fibroblastos/metabolismo , Perfilação da Expressão Gênica , Proteínas Hedgehog/metabolismo , Código das Histonas , Camundongos , Proteínas Proto-Oncogênicas c-bcl-6/metabolismo , RNA-Seq , Receptores Notch/metabolismo , Transdução de Sinais/genética , Via de Sinalização Wnt/genética
6.
Cell ; 173(6): 1370-1384.e16, 2018 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-29856955

RESUMO

The cerebral cortex underwent rapid expansion and increased complexity during recent hominid evolution. Gene duplications constitute a major evolutionary force, but their impact on human brain development remains unclear. Using tailored RNA sequencing (RNA-seq), we profiled the spatial and temporal expression of hominid-specific duplicated (HS) genes in the human fetal cortex and identified a repertoire of 35 HS genes displaying robust and dynamic patterns during cortical neurogenesis. Among them NOTCH2NL, human-specific paralogs of the NOTCH2 receptor, stood out for their ability to promote cortical progenitor maintenance. NOTCH2NL promote the clonal expansion of human cortical progenitors, ultimately leading to higher neuronal output. At the molecular level, NOTCH2NL function by activating the Notch pathway through inhibition of cis Delta/Notch interactions. Our study uncovers a large repertoire of recently evolved genes active during human corticogenesis and reveals how human-specific NOTCH paralogs may have contributed to the expansion of the human cortex.


Assuntos
Córtex Cerebral/metabolismo , Regulação da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Proteínas de Membrana/metabolismo , Neurogênese , Neurônios/metabolismo , Receptor Notch2/genética , Sequência de Aminoácidos , Proteínas de Ligação ao Cálcio , Diferenciação Celular/genética , Análise por Conglomerados , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Hibridização In Situ , Células-Tronco Neurais/metabolismo , Transdução de Sinais
7.
Cell Rep ; 23(9): 2732-2743, 2018 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-29847802

RESUMO

The transplantation of pluripotent stem-cell-derived neurons constitutes a promising avenue for the treatment of several brain diseases. However, their potential for the repair of the cerebral cortex remains unclear, given its complexity and neuronal diversity. Here, we show that human visual cortical cells differentiated from embryonic stem cells can be transplanted and can integrate successfully into the lesioned mouse adult visual cortex. The transplanted human neurons expressed the appropriate repertoire of markers of six cortical layers, projected axons to specific visual cortical targets, and were synaptically active within the adult brain. Moreover, transplant maturation and integration were much less efficient following transplantation into the lesioned motor cortex, as previously observed for transplanted mouse cortical neurons. These data constitute an important milestone for the potential use of human PSC-derived cortical cells for the reassembly of cortical circuits and emphasize the importance of cortical areal identity for successful transplantation.


Assuntos
Envelhecimento/patologia , Neurônios/transplante , Células-Tronco Pluripotentes/citologia , Córtex Visual/patologia , Animais , Axônios/metabolismo , Biomarcadores/metabolismo , Córtex Cerebral/citologia , Células-Tronco Embrionárias Humanas/citologia , Humanos , Camundongos Endogâmicos NOD , Camundongos SCID , Especificidade de Órgãos , Sinapses/metabolismo , Telencéfalo/metabolismo
8.
Cancer Cell ; 26(6): 797-812, 2014 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-25490446

RESUMO

Disrupted differentiation during development can lead to oncogenesis, but the underlying mechanisms remain poorly understood. Here we identify BCL6, a transcriptional repressor and lymphoma oncoprotein, as a pivotal factor required for neurogenesis and tumor suppression of medulloblastoma (MB). BCL6 is necessary for and capable of preventing the development of GNP-derived MB in mice, and can block the growth of human MB cells in vitro. BCL6 neurogenic and oncosuppressor effects rely on direct transcriptional repression of Gli1 and Gli2 effectors of the SHH pathway, through recruitment of BCOR corepressor and SIRT1 deacetylase. Our findings identify the BCL6/BCOR/SIRT1 complex as a potent repressor of the SHH pathway in normal and oncogenic neural development, with direct diagnostic and/or therapeutic relevance for SHH MB.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Meduloblastoma/patologia , Neurogênese , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Repressoras/metabolismo , Transdução de Sinais , Sirtuína 1/metabolismo , Animais , Linhagem Celular Tumoral , Cerebelo/metabolismo , Humanos , Fatores de Transcrição Kruppel-Like/metabolismo , Meduloblastoma/metabolismo , Camundongos , Camundongos Transgênicos , Proteínas Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-bcl-6 , Transativadores/metabolismo , Proteína GLI1 em Dedos de Zinco
9.
Neuron ; 77(3): 440-56, 2013 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-23395372

RESUMO

The study of human cortical development has major implications for brain evolution and diseases but has remained elusive due to paucity of experimental models. Here we found that human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), cultured without added morphogens, recapitulate corticogenesis leading to the sequential generation of functional pyramidal neurons of all six layer identities. After transplantation into mouse neonatal brain, human ESC-derived cortical neurons integrated robustly and established specific axonal projections and dendritic patterns corresponding to native cortical neurons. The differentiation and connectivity of the transplanted human cortical neurons complexified progressively over several months in vivo, culminating in the establishment of functional synapses with the host circuitry. Our data demonstrate that human cortical neurons generated in vitro from ESC/iPSC can develop complex hodological properties characteristic of the cerebral cortex in vivo, thereby offering unprecedented opportunities for the modeling of human cortex diseases and brain repair.


Assuntos
Encéfalo/citologia , Células-Tronco Embrionárias/citologia , Rede Nervosa/fisiologia , Células-Tronco Pluripotentes/fisiologia , Células Piramidais/fisiologia , 6-Ciano-7-nitroquinoxalina-2,3-diona/farmacologia , Fatores Etários , Animais , Axônios/fisiologia , Bromodesoxiuridina , Cálcio/metabolismo , Diferenciação Celular , Transplante de Células , Células Cultivadas , Dendritos/fisiologia , Potenciais Evocados/fisiologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Feminino , Feto , Corantes Fluorescentes/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Proteínas de Fluorescência Verde/genética , Humanos , Técnicas In Vitro , Camundongos , Microscopia Eletrônica de Transmissão , Proteínas Associadas aos Microtúbulos/metabolismo , Rede Nervosa/ultraestrutura , Proteínas do Tecido Nervoso/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Técnicas de Patch-Clamp , Gravidez , Células Piramidais/citologia , RNA Mensageiro/metabolismo , Sinapses/metabolismo , Sinapses/ultraestrutura , Potenciais Sinápticos/fisiologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transdução Genética , Tirosina 3-Mono-Oxigenase/metabolismo , Valina/análogos & derivados , Valina/farmacologia , Proteína Vesicular 1 de Transporte de Glutamato/metabolismo
10.
Nat Neurosci ; 15(12): 1627-35, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23160044

RESUMO

During neurogenesis, neural stem/progenitor cells (NPCs) undergo an irreversible fate transition to become neurons. The Notch pathway is important for this process, and repression of Notch-dependent Hes genes is essential for triggering differentiation. However, Notch signaling often remains active throughout neuronal differentiation, implying a change in the transcriptional responsiveness to Notch during the neurogenic transition. We identified Bcl6, an oncogene, as encoding a proneurogenic factor that is required for proper neurogenesis of the mouse cerebral cortex. BCL6 promoted the neurogenic conversion by switching the composition of Notch-dependent transcriptional complexes at the Hes5 promoter. BCL6 triggered exclusion of the co-activator Mastermind-like 1 and recruitment of the NAD(+)-dependent deacetylase Sirt1, which was required for BCL6-dependent neurogenesis. The resulting epigenetic silencing of Hes5 led to neuronal differentiation despite active Notch signaling. Our findings suggest a role for BCL6 in neurogenesis and uncover Notch-BCL6-Sirt1 interactions that may affect other aspects of physiology and disease.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/fisiologia , Diferenciação Celular , Proteínas de Ligação a DNA/fisiologia , Repressão Epigenética/fisiologia , Neurogênese/fisiologia , Receptores Notch/antagonistas & inibidores , Proteínas Repressoras/fisiologia , Sirtuína 1/fisiologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/antagonistas & inibidores , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Diferenciação Celular/genética , Células Cultivadas , Proteínas de Ligação a DNA/genética , Células-Tronco Embrionárias/fisiologia , Repressão Epigenética/genética , Feminino , Inativação Gênica , Marcação de Genes/métodos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurogênese/genética , Gravidez , Transporte Proteico/genética , Proteínas Proto-Oncogênicas c-bcl-6 , Receptores Notch/genética , Proteínas Repressoras/antagonistas & inibidores , Proteínas Repressoras/genética , Sirtuína 1/genética
11.
Cereb Cortex ; 22(7): 1678-89, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21940705

RESUMO

The patterning of cortical areas is controlled by a combination of intrinsic factors that are expressed in the cortex and external signals such as inputs from the thalamus. EphA7 is a guidance receptor that is involved in key aspects of cortical development and is expressed in gradients within developing cortical areas. Here, we identified a regulatory element of the EphA7 promoter, named pA7, that can recapitulate salient features of the pattern of expression of EphA7, including cortical gradients. Using a pA7-Green fluorescent Protein (GFP) mouse reporter line, we isolated cortical neuron populations displaying different levels of EphA7/GFP expression. Transcriptome analysis of these populations enabled to identify many differentially expressed genes, including 26 transcription factors with putative binding sites in the pA7 element. Among these, Pbx1 was found to bind directly to the EphA7 promoter in the developing cortex. All genes validated further were confirmed to be expressed differentially in the developing cortex, similarly to EphA7. Their expression was unchanged in mutant mice defective for thalamocortical projections, indicating a transcriptional control largely intrinsic to the cortex. Our study identifies a novel repertoire of cortical neuron genes that may act upstream of, or together with EphA7, to control the patterning of cortical areas.


Assuntos
Córtex Cerebral/embriologia , Córtex Cerebral/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Receptor EphA7/metabolismo , Fatores de Transcrição/metabolismo , Ativação Transcricional/fisiologia , Transcriptoma/fisiologia , Animais , Camundongos
12.
PLoS One ; 6(3): e17753, 2011 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-21445258

RESUMO

The developmental mechanisms through which the cerebral cortex increased in size and complexity during primate evolution are essentially unknown. To uncover genetic networks active in the developing cerebral cortex, we combined three-dimensional reconstruction of human fetal brains at midgestation and whole genome expression profiling. This novel approach enabled transcriptional characterization of neurons from accurately defined cortical regions containing presumptive Broca and Wernicke language areas, as well as surrounding associative areas. We identified hundreds of genes displaying differential expression between the two regions, but no significant difference in gene expression between left and right hemispheres. Validation by qRTPCR and in situ hybridization confirmed the robustness of our approach and revealed novel patterns of area- and layer-specific expression throughout the developing cortex. Genes differentially expressed between cortical areas were significantly associated with fast-evolving non-coding sequences harboring human-specific substitutions that could lead to divergence in their repertoires of transcription factor binding sites. Strikingly, while some of these sequences were accelerated in the human lineage only, many others were accelerated in chimpanzee and/or mouse lineages, indicating that genes important for cortical development may be particularly prone to changes in transcriptional regulation across mammals. Genes differentially expressed between cortical regions were also enriched for transcriptional targets of FoxP2, a key gene for the acquisition of language abilities in humans. Our findings point to a subset of genes with a unique combination of cortical areal expression and evolutionary patterns, suggesting that they play important roles in the transcriptional network underlying human-specific neural traits.


Assuntos
Evolução Biológica , Córtex Cerebral/embriologia , Regulação da Expressão Gênica no Desenvolvimento , Perfilação da Expressão Gênica , Humanos , Hibridização In Situ , Sequências Reguladoras de Ácido Nucleico , Reação em Cadeia da Polimerase Via Transcriptase Reversa
13.
Cell Microbiol ; 10(3): 606-17, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17979982

RESUMO

Virus entry is a major step in which host-cell lipids can play an essential role. In this report, we investigated the importance of sphingolipids in hepatitis C virus (HCV) entry. For this purpose, sphingomyelin present in the plasma membrane of target cells was hydrolysed into ceramide by sphingomyelinase treatment. Interestingly, ceramide enrichment of the plasma membrane strongly inhibited HCV entry. To understand how ceramide affected HCV entry, we analysed the effect of ceramide enrichment of the plasma membrane on three cell-surface molecules identified as entry factors for HCV: CD81 tetraspanin, scavenger receptor BI and Claudin-1. These proteins, which we found to be mainly associated with detergent-soluble membranes in Huh-7 cells, were not relocated in detergent-resistant microdomains after sphingomyelin hydrolysis into ceramide. Importantly, ceramide enrichment of the plasma membrane led to a 50% decrease in cell-surface CD81, which was due to its ATP-independent internalization. Our results strongly suggest that the ceramide-induced internalization of CD81 is responsible for the inhibitory effect of ceramide on HCV entry. Together, these data indicate that some specific lipids of the plasma membrane are essential for HCV entry and highlight plasma membrane lipids as potential targets to block HCV entry.


Assuntos
Antígenos CD/metabolismo , Membrana Celular/metabolismo , Ceramidas/metabolismo , Hepacivirus/fisiologia , Internalização do Vírus , Linhagem Celular , Claudina-1 , Humanos , Proteínas de Membrana/metabolismo , Receptores Depuradores Classe B/metabolismo , Esfingomielina Fosfodiesterase/metabolismo , Esfingomielinas/metabolismo , Tetraspanina 28
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