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1.
Science ; 368(6486): 48-53, 2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32241942

RESUMO

Neural stem cells (NSCs) in the developing and postnatal brain have distinct positional identities that dictate the types of neurons they generate. Although morphogens initially establish NSC positional identity in the neural tube, it is unclear how such regional differences are maintained as the forebrain grows much larger and more anatomically complex. We found that the maintenance of NSC positional identity in the murine brain requires a mixed-lineage leukemia 1 (Mll1)-dependent epigenetic memory system. After establishment by sonic hedgehog, ventral NSC identity became independent of this morphogen. Even transient MLL1 inhibition caused a durable loss of ventral identity, resulting in the generation of neurons with the characteristics of dorsal NSCs in vivo. Thus, spatial information provided by morphogens can be transitioned to epigenetic mechanisms that maintain regionally distinct developmental programs in the forebrain.


Assuntos
Impressão Genômica , Histona-Lisina N-Metiltransferase/fisiologia , Proteína de Leucina Linfoide-Mieloide/fisiologia , Células-Tronco Neurais/fisiologia , Neurogênese/genética , Prosencéfalo/citologia , Prosencéfalo/embriologia , Fator Nuclear 1 de Tireoide/genética , Animais , Proteínas Hedgehog/metabolismo , Histona-Lisina N-Metiltransferase/genética , Camundongos , Camundongos Mutantes , Proteína de Leucina Linfoide-Mieloide/genética , Células-Tronco Neurais/citologia , Transcriptoma
2.
Life Sci ; 248: 117468, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32105705

RESUMO

AIMS: Treatment with 5-fluorouracil (5-FU) can cause impairment to adult hippocampal neurogenesis, resulting in cognitive deficits. As melatonin has been shown to enhance memory and hippocampal neurogenesis in animal models, this research investigated the neuroprotective effects of melatonin against spatial memory and hippocampal neurogenesis impairment in 5-fluorouracil (5-FU)-treated rats. MATERIALS AND METHODS: Four-Five weeks old male Spraque-Dawley rats weighing between 180 and 200 g were used. Animals were maintained under standard laboratory conditions with 25 °C and 12 h light/dark cycle. Animal were administered intravenous (i.v.) injections of 5-FU (25 mg/kg) 5 times every 3 days starting on day 9 of the experiment. The rats were divided into preventive, recovery, and throughout groups and co-treated with melatonin (8 mg/kg, i.p.) once daily (at 7.00 pm) for 21 days prior to, after, and throughout 5-FU treatment, respectively. Spatial memory was assessed using a novel object location (NOL) test. Hippocampal neurogenesis was then examined using Ki67, bromodeoxyuridine (BrdU), and doublecortin (DCX) immunohistochemistry staining. KEY FINDINGS: Melatonin administration was able to both protect the subjects from and reverse spatial memory deficits. 5-FU was also found to reduce the generation of hippocampal newborn neurons. However, co-treatment with melatonin ameliorated the reductions in neurogenesis caused by 5-FU. SIGNIFICANCE: These findings suggest that melatonin administration was able to ameliorate the 5-FU-induced spatial memory deficits associated with neurogenesis. The present work will be valuable for patients who suffer memory deficits from 5-FU chemotherapy.


Assuntos
Disfunção Cognitiva/tratamento farmacológico , Fluoruracila/antagonistas & inibidores , Melatonina/farmacologia , Transtornos da Memória/tratamento farmacológico , Neurogênese/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Memória Espacial/efeitos dos fármacos , Animais , Antimetabólitos/efeitos adversos , Biomarcadores/metabolismo , Proliferação de Células/efeitos dos fármacos , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/fisiopatologia , Giro Denteado/efeitos dos fármacos , Giro Denteado/metabolismo , Giro Denteado/patologia , Esquema de Medicação , Fluoruracila/efeitos adversos , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Hipocampo/patologia , Injeções Intravenosas , Antígeno Ki-67/genética , Antígeno Ki-67/metabolismo , Masculino , Transtornos da Memória/metabolismo , Transtornos da Memória/fisiopatologia , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Neurogênese/genética , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Neuropeptídeos/genética , Neuropeptídeos/metabolismo , Ratos , Ratos Sprague-Dawley , Memória Espacial/fisiologia
3.
PLoS One ; 15(1): e0227917, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31978183

RESUMO

Experimental studies highlight the important role of the extracellular matrix (ECM) in the regulation of neuronal excitability and synaptic connectivity in the nervous system. In its turn, the neural ECM is formed in an activity-dependent manner. Its maturation closes the so-called critical period of neural development, stabilizing the efficient configurations of neural networks in the brain. ECM is locally remodeled by proteases secreted and activated in an activity-dependent manner into the extracellular space and this process is important for physiological synaptic plasticity. We ask if ECM remodeling may be exaggerated under pathological conditions and enable activity-dependent switches between different regimes of ECM expression. We consider an analytical model based on known mechanisms of interaction between neuronal activity and expression of ECM, ECM receptors and ECM degrading proteases. We demonstrate that either inhibitory or excitatory influence of ECM on neuronal activity may lead to the bistability of ECM expression, so two stable stationary states are observed. Noteworthy, only in the case when ECM has predominant inhibitory influence on neurons, the bistability is dependent on the activity of proteases. Excitatory ECM-neuron feedback influences may also result in spontaneous oscillations of ECM expression, which may coexist with a stable stationary state. Thus, ECM-neuronal interactions support switches between distinct dynamic regimes of ECM expression, possibly representing transitions into disease states associated with remodeling of brain ECM.


Assuntos
Matriz Extracelular/genética , Neurogênese/genética , Peptídeo Hidrolases/genética , Receptores de Superfície Celular/genética , Potenciais de Ação/genética , Animais , Encéfalo/metabolismo , Regulação da Expressão Gênica/genética , Humanos , Modelos Teóricos , Rede Nervosa/metabolismo , Plasticidade Neuronal/genética , Neurônios/metabolismo , Sinapses/genética
4.
Nat Commun ; 11(1): 382, 2020 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-31959746

RESUMO

Neurogenesis, a highly orchestrated process, entails the transition from a pluripotent to neural state and involves neural progenitor cells (NPCs) and neuronal/glial subtypes. However, the precise epigenetic mechanisms underlying fate decision remain poorly understood. Here, we delete KDM6s (JMJD3 and/or UTX), the H3K27me3 demethylases, in human embryonic stem cells (hESCs) and show that their deletion does not impede NPC generation from hESCs. However, KDM6-deficient NPCs exhibit poor proliferation and a failure to differentiate into neurons and glia. Mechanistically, both JMJD3 and UTX are found to be enriched in gene loci essential for neural development in hNPCs, and KDM6 impairment leads to H3K27me3 accumulation and blockade of DNA accessibility at these genes. Interestingly, forced expression of neuron-specific chromatin remodelling BAF (nBAF) rescues the neuron/glia defect in KDM6-deficient NPCs despite H3K27me3 accumulation. Our findings uncover the differential requirement of KDM6s in specifying NPCs and neurons/glia and highlight the contribution of individual epigenetic regulators in fate decisions in a human development model.


Assuntos
Diferenciação Celular/genética , Regulação da Expressão Gênica no Desenvolvimento , Histona Desmetilases/metabolismo , Histona Desmetilases com o Domínio Jumonji/metabolismo , Células-Tronco Neurais/fisiologia , Linhagem Celular , Proliferação de Células/genética , Metilação de DNA , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Células-Tronco Embrionárias/fisiologia , Epigênese Genética/fisiologia , Técnicas de Introdução de Genes , Técnicas de Inativação de Genes , Histona Desmetilases/genética , Histonas/genética , Histonas/metabolismo , Humanos , Histona Desmetilases com o Domínio Jumonji/genética , Neurogênese/genética , RNA-Seq
5.
Nat Commun ; 11(1): 195, 2020 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-31924768

RESUMO

The cyclin-dependent kinase inhibitor p57KIP2 is encoded by the imprinted Cdkn1c locus, exhibits maternal expression, and is essential for cerebral cortex development. How Cdkn1c regulates corticogenesis is however not clear. To this end we employ Mosaic Analysis with Double Markers (MADM) technology to genetically dissect Cdkn1c gene function in corticogenesis at single cell resolution. We find that the previously described growth-inhibitory Cdkn1c function is a non-cell-autonomous one, acting on the whole organism. In contrast we reveal a growth-promoting cell-autonomous Cdkn1c function which at the mechanistic level mediates radial glial progenitor cell and nascent projection neuron survival. Strikingly, the growth-promoting function of Cdkn1c is highly dosage sensitive but not subject to genomic imprinting. Collectively, our results suggest that the Cdkn1c locus regulates cortical development through distinct cell-autonomous and non-cell-autonomous mechanisms. More generally, our study highlights the importance to probe the relative contributions of cell intrinsic gene function and tissue-wide mechanisms to the overall phenotype.


Assuntos
Sobrevivência Celular , Córtex Cerebral/metabolismo , Inibidor de Quinase Dependente de Ciclina p57/genética , Inibidor de Quinase Dependente de Ciclina p57/metabolismo , Genômica , Neurogênese/fisiologia , Animais , Córtex Cerebral/crescimento & desenvolvimento , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Masculino , Camundongos , Camundongos Knockout , Neurogênese/genética , Neurônios/classificação , Neurônios/metabolismo , Fenótipo , Transcriptoma
6.
Nat Cell Biol ; 21(12): 1504-1517, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31792380

RESUMO

The enteric nervous system (ENS) predominantly originates from vagal neural crest (VNC) cells that emerge from the caudal hindbrain, invade the foregut and populate the gastrointestinal tract. However, the gene regulatory network (GRN) orchestrating the early specification of VNC remains unknown. Using an EdnrB enhancer, we generated a comprehensive temporal map of the chromatin and transcriptional landscape of VNC in the avian model, revealing three VNC cell clusters (neural, neurogenic and mesenchymal), each predetermined epigenetically prior to neural tube delamination. We identify and functionally validate regulatory cores (Sox10/Tfap2B/SoxB/Hbox) mediating each programme and elucidate their combinatorial activities with other spatiotemporally specific transcription factors (bHLH/NR). Our global deconstruction of the VNC-GRN in vivo sheds light on critical early regulatory mechanisms that may influence the divergent neural phenotypes in enteric neuropathies.


Assuntos
Linhagem da Célula/fisiologia , Cromatina/genética , Sistema Nervoso Entérico/fisiologia , Células-Tronco Mesenquimais/fisiologia , Crista Neural/fisiologia , Neurônios/fisiologia , Nervo Vago/fisiologia , Animais , Linhagem da Célula/genética , Galinhas/genética , Galinhas/fisiologia , Cromatina/fisiologia , Epigênese Genética/genética , Epigênese Genética/fisiologia , Redes Reguladoras de Genes/genética , Redes Reguladoras de Genes/fisiologia , Neurogênese/genética , Neurogênese/fisiologia , Fatores de Transcrição/genética , Transcrição Genética/genética
7.
Int J Mol Sci ; 21(1)2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31861329

RESUMO

Nuclear receptor related-1 (Nurr1) protein performs a crucial role in hippocampal neural stem cell (hNSC) development as well as cognitive functions. We previously demonstrated that the pharmacological stimulation of Nurr1 by amodiaquine (AQ) promotes spatial memory by enhancing adult hippocampal neurogenesis. However, the role of Nurr1 in the cell cycle regulation of the adult hippocampus has not been investigated. This study aimed to examine changes in the cell cycle-related molecules involved in adult hippocampal neurogenesis induced by Nurr1 pharmacological stimulation. Fluorescence-activated cell sorting (FACS) analysis showed that AQ improved the progression of cell cycle from G0/G1 to S phase in a dose-dependent manner, and MEK1 or PI3K inhibitors attenuated this progression. In addition, AQ treatment increased the expression of cell proliferation markers MCM5 and PCNA, and transcription factor E2F1. Furthermore, pharmacological stimulation of Nurr1 by AQ increased the expression levels of positive cell cycle regulators such as cyclin A and cyclin-dependent kinases (CDK) 2. In contrast, levels of CDK inhibitors p27KIP1 and p57KIP2 were reduced upon treatment with AQ. Similar to the in vitro results, RT-qPCR analysis of AQ-administered mice brains revealed an increase in the levels of markers of cell cycle progression, PCNA, MCM5, and Cdc25a. Finally, AQ administration resulted in decreased p27KIP1 and increased CDK2 levels in the dentate gyrus of the mouse hippocampus, as quantified immunohistochemically. Our results demonstrate that the pharmacological stimulation of Nurr1 in adult hNSCs by AQ promotes the cell cycle by modulating cell cycle-related molecules.


Assuntos
Células-Tronco Adultas/metabolismo , Ciclo Celular/genética , Hipocampo/citologia , Células-Tronco Neurais/metabolismo , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Células-Tronco Adultas/efeitos dos fármacos , Amodiaquina/farmacologia , Animais , Biomarcadores , Ciclo Celular/efeitos dos fármacos , Proliferação de Células , Giro Denteado/metabolismo , Fator de Transcrição E2F1/genética , Fator de Transcrição E2F1/metabolismo , Regulação da Expressão Gênica , Humanos , Imuno-Histoquímica , Masculino , Camundongos , Células-Tronco Neurais/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Neurogênese/genética , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Ratos
8.
PLoS Biol ; 17(10): e3000081, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31634368

RESUMO

In vitro models of postimplantation human development are valuable to the fields of regenerative medicine and developmental biology. Here, we report characterization of a robust in vitro platform that enabled high-content screening of multiple human pluripotent stem cell (hPSC) lines for their ability to undergo peri-gastrulation-like fate patterning upon bone morphogenetic protein 4 (BMP4) treatment of geometrically confined colonies and observed significant heterogeneity in their differentiation propensities along a gastrulation associable and neuralization associable axis. This cell line-associated heterogeneity was found to be attributable to endogenous Nodal expression, with up-regulation of Nodal correlated with expression of a gastrulation-associated gene profile, and Nodal down-regulation correlated with a preneurulation-associated gene profile expression. We harness this knowledge to establish a platform of preneurulation-like fate patterning in geometrically confined hPSC colonies in which fates arise because of a BMPs signalling gradient conveying positional information. Our work identifies a Nodal signalling-dependent switch in peri-gastrulation versus preneurulation-associated fate patterning in hPSC cells, provides a technology to robustly assay hPSC differentiation outcomes, and suggests conserved mechanisms of organized fate specification in differentiating epiblast and ectodermal tissues.


Assuntos
Proteína Morfogenética Óssea 4/farmacologia , Linhagem da Célula/efeitos dos fármacos , Regulação da Expressão Gênica no Desenvolvimento , Proteína Nodal/genética , Células-Tronco Pluripotentes/efeitos dos fármacos , Fenômenos Biomecânicos , Padronização Corporal/genética , Proteína Morfogenética Óssea 4/genética , Proteína Morfogenética Óssea 4/metabolismo , Técnicas de Cultura de Células , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Linhagem da Célula/genética , Gastrulação/efeitos dos fármacos , Gastrulação/genética , Perfilação da Expressão Gênica , Heterogeneidade Genética , Ensaios de Triagem em Larga Escala , Humanos , Modelos Biológicos , Neurogênese/efeitos dos fármacos , Neurogênese/genética , Proteína Nodal/metabolismo , Células-Tronco Pluripotentes/citologia , Células-Tronco Pluripotentes/metabolismo , Transdução de Sinais , Propriedades de Superfície
9.
Nat Commun ; 10(1): 3946, 2019 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-31477701

RESUMO

Cerebral cortex expansion is a hallmark of mammalian brain evolution; yet, how increased neurogenesis is coordinated with structural and functional development remains largely unclear. The T-box protein TBR2/EOMES is preferentially enriched in intermediate progenitors and supports cortical neurogenesis expansion. Here we show that TBR2 regulates fine-scale spatial and circuit organization of excitatory neurons in addition to enhancing neurogenesis in the mouse cortex. TBR2 removal leads to a significant reduction in neuronal, but not glial, output of individual radial glial progenitors as revealed by mosaic analysis with double markers. Moreover, in the absence of TBR2, clonally related excitatory neurons become more laterally dispersed and their preferential synapse development is impaired. Interestingly, TBR2 directly regulates the expression of Protocadherin 19 (PCDH19), and simultaneous PCDH19 expression rescues neurogenesis and neuronal organization defects caused by TBR2 removal. Together, these results suggest that TBR2 coordinates neurogenesis expansion and precise microcircuit assembly via PCDH19 in the mammalian cortex.


Assuntos
Caderinas/genética , Córtex Cerebral/metabolismo , Neurogênese/genética , Neurônios/metabolismo , Proteínas com Domínio T/genética , Animais , Caderinas/metabolismo , Córtex Cerebral/citologia , Córtex Cerebral/embriologia , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica no Desenvolvimento , Células HEK293 , Humanos , Camundongos Knockout , Camundongos Transgênicos , Interferência de RNA , Sinapses/metabolismo , Proteínas com Domínio T/metabolismo
10.
Int J Mol Sci ; 20(18)2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31509934

RESUMO

In addition to its role as an endocrine messenger, growth hormone (GH) also acts as a neurotrophic factor in the central nervous system (CNS), whose effects are involved in neuroprotection, axonal growth, and synaptogenic modulation. An increasing amount of clinical evidence shows a beneficial effect of GH treatment in patients with brain trauma, stroke, spinal cord injury, impaired cognitive function, and neurodegenerative processes. In response to injury, Müller cells transdifferentiate into neural progenitors and proliferate, which constitutes an early regenerative process in the chicken retina. In this work, we studied the long-term protective effect of GH after causing severe excitotoxic damage in the retina. Thus, an acute neural injury was induced via the intravitreal injection of kainic acid (KA, 20 µg), which was followed by chronic administration of GH (10 injections [300 ng] over 21 days). Damage provoked a severe disruption of several retinal layers. However, in KA-damaged retinas treated with GH, we observed a significant restoration of the inner plexiform layer (IPL, 2.4-fold) and inner nuclear layer (INL, 1.5-fold) thickness and a general improvement of the retinal structure. In addition, we also observed an increase in the expression of several genes involved in important regenerative pathways, including: synaptogenic markers (DLG1, NRXN1, GAP43); glutamate receptor subunits (NR1 and GRIK4); pro-survival factors (BDNF, Bcl-2 and TNF-R2); and Notch signaling proteins (Notch1 and Hes5). Interestingly, Müller cell transdifferentiation markers (Sox2 and FGF2) were upregulated by this long-term chronic GH treatment. These results are consistent with a significant increase in the number of BrdU-positive cells observed in the KA-damaged retina, which was induced by GH administration. Our data suggest that GH is able to facilitate the early proliferative response of the injured retina and enhance the regeneration of neurite interconnections.


Assuntos
Hormônio do Crescimento/farmacologia , Ácido Caínico/toxicidade , Regeneração/efeitos dos fármacos , Retina/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Fator Neurotrófico Derivado do Encéfalo/genética , Embrião de Galinha , Galinhas , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Neurogênese/genética , Neurogênese/fisiologia , Fármacos Neuroprotetores/farmacologia , Neurotoxinas/toxicidade , Receptor Notch1/genética , Regeneração/genética , Regeneração/fisiologia , Retina/metabolismo , Retina/fisiopatologia , Fatores de Transcrição SOXB1/genética
11.
Nat Commun ; 10(1): 3983, 2019 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-31484925

RESUMO

Hypoxic ischemia (HI) is an acute brain threat across all age groups. Therapeutic hypothermia ameliorates resulting injury in neonates but its side effects prevent routine use in adults. Hypothermia up-regulates a small protein subset that includes RNA-binding motif protein 3 (RBM3), which is neuroprotective under stressful conditions. Here we show how RBM3 stimulates neuronal differentiation and inhibits HI-induced apoptosis in the two areas of persistent adult neurogenesis, the subventricular zone (SVZ) and the subgranular zone (SGZ), while promoting neural stem/progenitor cell (NSPC) proliferation after HI injury only in the SGZ. RBM3 interacts with IGF2 mRNA binding protein 2 (IMP2), elevates its expression and thereby stimulates IGF2 release in SGZ but not SVZ-NSPCs. In summary, we describe niche-dependent regulation of neurogenesis after adult HI injury via the novel RBM3-IMP2-IGF2 signaling pathway.


Assuntos
Lesões Encefálicas/metabolismo , Hipóxia-Isquemia Encefálica/metabolismo , Fator de Crescimento Insulin-Like II/metabolismo , Células-Tronco Neurais/metabolismo , Proteínas de Ligação a RNA/metabolismo , Animais , Animais Recém-Nascidos , Lesões Encefálicas/genética , Células Cultivadas , Células HEK293 , Hipocampo/citologia , Hipocampo/crescimento & desenvolvimento , Hipocampo/metabolismo , Humanos , Hipóxia-Isquemia Encefálica/genética , Fator de Crescimento Insulin-Like II/genética , Ventrículos Laterais/citologia , Ventrículos Laterais/crescimento & desenvolvimento , Ventrículos Laterais/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células-Tronco Neurais/citologia , Neurogênese/genética , Proteínas de Ligação a RNA/genética , Transdução de Sinais/genética , Nicho de Células-Tronco
12.
Mol Cell ; 76(3): 473-484.e7, 2019 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-31494034

RESUMO

Enhancers can regulate the promoters of their target genes over very large genomic distances. It is widely assumed that mechanisms of enhancer action involve the reorganization of three-dimensional chromatin architecture, but this is poorly understood. The predominant model involves physical enhancer-promoter interaction by looping out the intervening chromatin. However, studying the enhancer-driven activation of the Sonic hedgehog gene (Shh), we have identified a change in chromosome conformation that is incompatible with this simple looping model. Using super-resolution 3D-FISH and chromosome conformation capture, we observe a decreased spatial proximity between Shh and its enhancers during the differentiation of embryonic stem cells to neural progenitors. We show that this can be recapitulated by synthetic enhancer activation, is impeded by chromatin-bound proteins located between the enhancer and the promoter, and appears to involve the catalytic activity of poly (ADP-ribose) polymerase. Our data suggest that models of enhancer-promoter communication need to encompass chromatin conformations other than looping.


Assuntos
Montagem e Desmontagem da Cromatina , Elementos Facilitadores Genéticos , Proteínas Hedgehog/metabolismo , Células-Tronco Embrionárias Murinas/metabolismo , Neurogênese , Neurônios/metabolismo , Regiões Promotoras Genéticas , Ativação Transcricional , Animais , Linhagem Celular , Regulação da Expressão Gênica no Desenvolvimento , Proteínas Hedgehog/genética , Camundongos , Modelos Genéticos , Neurogênese/genética , Conformação de Ácido Nucleico , Poli(ADP-Ribose) Polimerase-1/genética , Poli(ADP-Ribose) Polimerase-1/metabolismo , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo
13.
Int J Mol Sci ; 20(18)2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31527487

RESUMO

Methyl CpG binding protein 2 (MeCP2) was first identified as a nuclear protein with a transcriptional repressor role that recognizes DNA methylation marks. MeCP2 has a well-established function in neurodevelopment, as evidenced by the severe neurological impairments characteristic of the Rett syndrome (RTT) pathology and the MeCP2 duplication syndrome (MDS), caused by loss or gain of MeCP2 function, respectively. Research aimed at the underlying pathophysiological mechanisms of RTT and MDS has significantly advanced our understanding of MeCP2 functions in the nervous system. It has revealed, however, that MeCP2 has more varied and complex roles than previously thought. Here we review recent insights into the functions of MeCP2 in neurodevelopment and the less explored requirement for MeCP2 in adult brain function. We focus on the emerging view that MeCP2 is a global chromatin organizer. Finally, we discuss how the individual functions of MeCP2 in neurodevelopment and adulthood are linked to its role as a chromatin regulator.


Assuntos
Encéfalo/metabolismo , Cromatina/metabolismo , Proteína 2 de Ligação a Metil-CpG/metabolismo , Neurogênese , Animais , Encéfalo/patologia , Encéfalo/fisiopatologia , Diferenciação Celular , Cromatina/genética , Regulação da Expressão Gênica , Humanos , Neurogênese/genética , Processamento de Proteína Pós-Traducional , Transdução de Sinais
14.
Nat Commun ; 10(1): 3696, 2019 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-31420539

RESUMO

Despite the crucial physiological processes governed by neurons in the hypothalamic arcuate nucleus (ARC), such as growth, reproduction and energy homeostasis, the developmental pathways and regulators for ARC neurons remain understudied. Our single cell RNA-seq analyses of mouse embryonic ARC revealed many cell type-specific markers for developing ARC neurons. These markers include transcription factors whose expression is enriched in specific neuronal types and often depleted in other closely-related neuronal types, raising the possibility that these transcription factors play important roles in the fate commitment or differentiation of specific ARC neuronal types. We validated this idea with the two transcription factors, Foxp2 enriched for Ghrh-neurons and Sox14 enriched for Kisspeptin-neurons, using Foxp2- and Sox14-deficient mouse models. Taken together, our single cell transcriptome analyses for the developing ARC uncovered a panel of transcription factors that are likely to form a gene regulatory network to orchestrate fate specification and differentiation of ARC neurons.


Assuntos
Núcleo Arqueado do Hipotálamo/citologia , Regulação da Expressão Gênica no Desenvolvimento , Neurônios/metabolismo , Animais , Núcleo Arqueado do Hipotálamo/embriologia , Fatores de Transcrição Forkhead/genética , Perfilação da Expressão Gênica , Hormônio Liberador de Hormônio do Crescimento/metabolismo , Kisspeptinas/metabolismo , Camundongos , Camundongos Knockout , Neurogênese/genética , Proteínas Repressoras/genética , Fatores de Transcrição SOXB2/genética , Análise de Célula Única
15.
PLoS Genet ; 15(8): e1008243, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31386652

RESUMO

Tubulin genes encode a series of homologous proteins used to construct microtubules which are essential for multiple cellular processes. Neural development is particularly reliant on functional microtubule structures. Tubulin genes comprise a large family of genes with very high sequence similarity between multiple family members. Human genetics has demonstrated that a large spectrum of cortical malformations are associated with de novo heterozygous mutations in tubulin genes. However, the absolute requirement for many of these genes in development and disease has not been previously tested in genetic loss of function models. Here we directly test the requirement for Tuba1a, Tubb2a and Tubb2b in the mouse by deleting each gene individually using CRISPR-Cas9 genome editing. We show that loss of Tubb2a or Tubb2b does not impair survival but does lead to relatively mild cortical malformation phenotypes. In contrast, loss of Tuba1a is perinatal lethal and leads to significant forebrain dysmorphology. We also present a novel mouse ENU allele of Tuba1a with phenotypes similar to the null allele. This demonstrates the requirements for each of the tubulin genes and levels of functional redundancy are quite different throughout the gene family. The ability of the mouse to survive in the absence of some tubulin genes known to cause disease in humans suggests future intervention strategies for these devastating tubulinopathy diseases.


Assuntos
Malformações do Desenvolvimento Cortical/genética , Neurogênese/genética , Córtex Sensório-Motor/embriologia , Tubulina (Proteína)/genética , Alelos , Animais , Sistemas CRISPR-Cas , Modelos Animais de Doenças , Embrião de Mamíferos , Etilnitrosoureia/toxicidade , Feminino , Deleção de Genes , Edição de Genes , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Masculino , Malformações do Desenvolvimento Cortical/mortalidade , Malformações do Desenvolvimento Cortical/patologia , Camundongos , Camundongos Transgênicos , Microtúbulos/genética , Modelos Animais , Mutagênese/efeitos dos fármacos , Córtex Sensório-Motor/anormalidades , Especificidade da Espécie , Tubulina (Proteína)/metabolismo
16.
Int J Mol Sci ; 20(17)2019 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-31450858

RESUMO

MicroRNAs, also called miRNAs or simply miR-, represent a unique class of non-coding RNAs that have gained exponential interest during recent years because of their determinant involvement in regulating the expression of several genes. Despite the increasing number of mature miRNAs recognized in the human species, only a limited proportion is engaged in the ontogeny of the central nervous system (CNS). miRNAs also play a pivotal role during the transition of normal neural stem cells (NSCs) into tumor-forming NSCs. More specifically, extensive studies have identified some shared miRNAs between NSCs and neural cancer stem cells (CSCs), namely miR-7, -124, -125, -181 and miR-9, -10, -130. In the context of NSCs, miRNAs are intercalated from embryonic stages throughout the differentiation pathway in order to achieve mature neuronal lineages. Within CSCs, under a different cellular context, miRNAs perform tumor suppressive or oncogenic functions that govern the homeostasis of brain tumors. This review will draw attention to the most characterizing studies dealing with miRNAs engaged in neurogenesis and in the tumoral neural stem cell context, offering the reader insight into the power of next generation miRNA-targeted therapies against brain malignances.


Assuntos
MicroRNAs/genética , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neurais/metabolismo , Animais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Diferenciação Celular/genética , Perfilação da Expressão Gênica , Humanos , Células-Tronco Neoplásicas/patologia , Neurogênese/genética , Transcriptoma
17.
Nat Commun ; 10(1): 3465, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31371714

RESUMO

Brain morphogenesis is an important process contributing to higher-order cognition, however our knowledge about its biological basis is largely incomplete. Here we analyze 118 neuroanatomical parameters in 1,566 mutant mouse lines and identify 198 genes whose disruptions yield NeuroAnatomical Phenotypes (NAPs), mostly affecting structures implicated in brain connectivity. Groups of functionally similar NAP genes participate in pathways involving the cytoskeleton, the cell cycle and the synapse, display distinct fetal and postnatal brain expression dynamics and importantly, their disruption can yield convergent phenotypic patterns. 17% of human unique orthologues of mouse NAP genes are known loci for cognitive dysfunction. The remaining 83% constitute a vast pool of genes newly implicated in brain architecture, providing the largest study of mouse NAP genes and pathways. This offers a complementary resource to human genetic studies and predict that many more genes could be involved in mammalian brain morphogenesis.


Assuntos
Encéfalo , Estudos de Associação Genética , Morfogênese/genética , Neuroanatomia , Neurogênese/genética , Animais , Encéfalo/metabolismo , Ciclo Celular , Cognição , Citoesqueleto , Redes Reguladoras de Genes , Genes Letais/genética , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Animais , Mutação , Fenótipo , Sinapses
18.
Ecotoxicol Environ Saf ; 183: 109498, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31377521

RESUMO

2',2',4,4'-tetrabromo diphenyl ether (BDE-47), one of the most abundant congeners of commercial pentaBDE utilized as flame retardants, has been phased out of production due to its potential neural toxicity and endocrine disrupting activities, and yet still present in the environment. Several alternatives to BDE-47, including tetrabromobisphenol A (TBBPA), tetrabromobisphenol S (TBBPS), tetrachlorobisphenol A (TCBPA) and decabromodiphenyl ether (BDE-209), are presently employed without restrictions and their potential toxic effects on human neural development are still unclear. In this study, we utilized a human neural stem cell (hNSC)-based system to evaluate the potential developmental neurotoxic effects of the above-mentioned five chemicals, at environment and human exposure relevant concentrations. We found that those compounds slightly altered the expression of hNSC identity markers (SOX2, SOX3 and NES), without impairing cell viability or proliferation, in part by either modulating glycogen synthase kinase 3 beta (GSK3ß) signaling (TBBPS, TCBPA and BDE-47), and slightly disturbing the NOTCH pathway (TBBPA, TBBPS and TCBPA). Moreover, the five chemicals seemed to alter hNSC differentiation by perturbing triiodothyronine (T3) cellular signaling. Thus, our findings suggest that the five compounds, especially TBBPS, TCBPA, and BDE-47, may affect hNSC self-renewal and differentiation abilities and potentially elicit neural developmental toxicity.


Assuntos
Retardadores de Chama/toxicidade , Regulação da Expressão Gênica/efeitos dos fármacos , Glicogênio Sintase Quinase 3 beta/metabolismo , Células-Tronco Neurais/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Tri-Iodotironina/metabolismo , Humanos , Hidrocarbonetos Halogenados/toxicidade , Células-Tronco Neurais/metabolismo , Células-Tronco Neurais/patologia , Neurogênese/efeitos dos fármacos , Neurogênese/genética
19.
BMC Complement Altern Med ; 19(1): 167, 2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31286956

RESUMO

BACKGROUND: Centella asiatica (L.) Urban, known as Indian Pennywort, is a tropical medicinal plant from Apiaceae family native to Southeast Asian countries. It has been widely used as a nerve tonic in Ayuverdic medicine since ancient times. However, whether it can substitute for neurotrophic factors to induce human mesenchymal stem cell (hMSCs) differentiation into the neural lineage remains unknown. This study aimed to investigate the effect of a raw extract of C. asiatica (L.) (RECA) on the neural differentiation of hMSCs in vitro. METHODS: The hMSCs derived from human Wharton's jelly umbilical cord (hWJMSCs; n = 6) were treated with RECA at different concentrations; 400, 800, 1200, 1600, 2000 and 2400 µg/ml. The cytotoxicity of RECA was evaluated via the MTT (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) and cell proliferation assays. The hWJMSCs were then induced to neural lineage for 9 days either with RECA alone or RECA in combination with neurotrophic factors (NF). Cell morphological changes were observed under an inverted microscope, while the expression of the neural markers S100ß, p75 NGFR, MBP, GFAP and MOG was analyzed by quantitative polymerase chain reaction and immunocytochemistry. The cell cycle profile of differentiated and undifferentiated hWJMSCs was investigated through cell cycle analysis. RESULTS: RECA exerted effects on both proliferation and neural differentiation of hWJMSCs in a dose-dependent manner. RECA reduced the proliferation of hWJMSCs and was cytotoxic to cells above 1600 µg/ml, with IC50 value, 1875 ± 55.67 µg/ml. In parallel with the reduction in cell viability, cell enlargement was also observed at the end of the induction. Cells treated with RECA alone had more obvious protein expression of the neural markers compared to the other groups. Meanwhile, gene expression of the aforementioned markers was detected at low levels across the experimental groups. The supplementation of hWJMSCs with RECA did not change the normal life cycle of the cells. CONCLUSIONS: Although RECA reduced the proliferation of hWJMSCs, a low dose of RECA (400 µg/ml), alone or in combination of neurotrophic factors (NF + RECA 400 µg/ml), has the potential to differentiate hWJMSCs into Schwann cells and other neural lineage cells.


Assuntos
Centella/química , Células-Tronco Mesenquimais/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Extratos Vegetais/farmacologia , Ciclo Celular , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Feminino , Expressão Gênica/efeitos dos fármacos , Humanos , Células-Tronco Mesenquimais/citologia , Neurogênese/genética , Extratos Vegetais/toxicidade , Gravidez , Geleia de Wharton
20.
Int J Mol Sci ; 20(13)2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31261761

RESUMO

This work explores for the first time the potential contribution of microRNAs (miRNAs) to the pathophysiology of the GM2 gangliosidosis, a group of Lysosomal Storage Diseases. In spite of the genetic origin of GM2 gangliosidosis, the cascade of events leading from the gene/protein defects to the cell dysfunction and death is not fully elucidated. At present, there is no cure for patients. Taking advantage of the animal models of two forms of GM2 gangliosidosis, Tay-Sachs (TSD) and Sandhoff (SD) diseases, we performed a microRNA screening in the brain subventricular zone (SVZ) and striatum (STR), which feature the neurogenesis and neurodegeneration states, respectively, in adult mutant mice. We found abnormal expression of a panel of miRNAs involved in lipid metabolism, CNS development and homeostasis, and neuropathological processes, highlighting region- and disease-specific profiles of miRNA expression. Moreover, by using a computational analysis approach, we identified a unique disease- (SD or TSD) and brain region-specific (SVZ vs. STR) miRNAs signatures of predicted networks potentially related to the pathogenesis of the diseases. These results may contribute to the understanding of GM2 gangliosidosis pathophysiology, with the aim of developing effective treatments.


Assuntos
Corpo Estriado/metabolismo , Gangliosidoses GM2/genética , Redes Reguladoras de Genes , Ventrículos Laterais/metabolismo , MicroRNAs/genética , Transcriptoma , Animais , Gangliosidoses GM2/metabolismo , Metabolismo dos Lipídeos/genética , Camundongos , Camundongos Endogâmicos C57BL , Neurogênese/genética
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