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1.
J Vet Sci ; 20(2): e3, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30944526

RESUMO

The development of long-term surviving fetal cell cultures from primary cell tissue from the developing brain is important for facilitating studies investigating neural development and for modelling neural disorders and brain congenital defects. The field faces current challenges in co-culturing both progenitors and neurons long-term. Here, we culture for the first time, porcine fetal cells from the dorsal telencephalon at embryonic day (E) 50 and E60 in conditions that promoted both the survival of progenitor cells and young neurons. We applied a novel protocol designed to collect, isolate and promote survival of both progenitors and young neurons. Herein, we used a combination of low amount of fetal bovine serum, together with pro-survival factors, including basic fibroblast growth factor and retinoic acid, together with arabinofuranosylcytosine and could maintain progenitors and facilitate in vitro differentiation into calbindin 1+ neurons and reelin+ interneurons for a period of 7 days. Further improvements to the protocol that might extend the survival of the fetal primary neural cells would be beneficial. The development of new porcine fetal culture methods is of value for the field, given the pig's neuroanatomical and developmental similarities to the human brain.


Assuntos
Neurônios/citologia , Células-Tronco/citologia , Telencéfalo/embriologia , Animais , Contagem de Células/veterinária , Células Cultivadas , Feminino , Masculino , Suínos/embriologia , Telencéfalo/citologia
2.
eNeuro ; 6(1)2019.
Artigo em Inglês | MEDLINE | ID: mdl-30873428

RESUMO

LIM domain binding protein 1 (LDB1) is a protein cofactor that participates in several multiprotein complexes with transcription factors that regulate mouse forebrain development. Since Ldb1 null mutants display early embryonic lethality, we used a conditional knockout strategy to examine the role of LDB1 in early forebrain development using multiple Cre lines. Loss of Ldb1 from E8.75 using Foxg1Cre caused a disruption of midline boundary structures in the dorsal telencephalon. While this Cre line gave the expected pattern of recombination of the floxed Ldb1 locus, unexpectedly, standard Cre lines that act from embryonic day (E)10.5 (Emx1Cre) and E11.5 (NesCre) did not show efficient or complete recombination in the dorsal telencephalon by E12.5. Intriguingly, this effect was specific to the Ldb1 floxed allele, since three other lines including floxed Ai9 and mTmG reporters, and a floxed Lhx2 line, each displayed the expected spatial patterns of recombination. Furthermore, the incomplete recombination of the floxed Ldb1 locus using NesCre was limited to the dorsal telencephalon, while the ventral telencephalon and the diencephalon displayed the expected loss of Ldb1. This permitted us to examine the requirement for LDB1 in the development of the thalamus in a context wherein the cortex continued to express Ldb1. We report that the somatosensory VB nucleus is profoundly shrunken upon loss of LDB1. Our findings highlight the unusual nature of the Ldb1 locus in terms of recombination efficiency, and also report a novel role for LDB1 during the development of the thalamus.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Proteínas com Domínio LIM/metabolismo , Telencéfalo/embriologia , Telencéfalo/metabolismo , Tálamo/embriologia , Tálamo/metabolismo , Animais , Animais Recém-Nascidos , Proteínas de Ligação a DNA/genética , Feminino , Proteínas com Domínio LIM/genética , Masculino , Camundongos Transgênicos
3.
Dev Growth Differ ; 61(3): 252-262, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30843193

RESUMO

The forebrain develops into the telencephalon, diencephalon, and optic vesicle (OV). The OV further develops into the optic cup, the inner and outer layers of which develop into the neural retina and retinal pigmented epithelium (RPE), respectively. We studied the change in fate of the OV by using embryonic transplantation and explant culture methods. OVs excised from 10-somite stage chick embryos were freed from surrounding tissues (the surface ectoderm and mesenchyme) and were transplanted back to their original position in host embryos. Expression of neural retina-specific genes, such as Rax and Vsx2 (Chx10), was downregulated in the transplants. Instead, expression of the telencephalon-specific gene Emx1 emerged in the proximal region of the transplants, and in the distal part of the transplants close to the epidermis, expression of an RPE-specific gene Mitf was observed. Explant culture studies showed that when OVs were cultured alone, Rax was continuously expressed regardless of surrounding tissues (mesenchyme and epidermis). When OVs without surrounding tissues were cultured in close contact with the anterior forebrain, Rax expression became downregulated in the explants, and Emx1 expression became upregulated. These findings indicate that chick OVs at stage 10 are bi-potential with respect to their developmental fates, either for the neural retina or for the telencephalon, and that the surrounding tissues have a pivotal role in their actual fates. An in vitro tissue culture model suggests that under the influence of the anterior forebrain and/or its surrounding tissues, the OV changes its fate from the retina to the telencephalon.


Assuntos
Retina/embriologia , Animais , Padronização Corporal/fisiologia , Diferenciação Celular/fisiologia , Embrião de Galinha , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Imuno-Histoquímica , Retina/citologia , Retina/metabolismo , Pigmentos da Retina/metabolismo , Telencéfalo/citologia , Telencéfalo/embriologia , Telencéfalo/metabolismo
4.
Development ; 146(5)2019 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-30770393

RESUMO

During neocortical development, neurons are produced by a diverse pool of neural progenitors. A subset of progenitors express the Cux2 gene and are fate restricted to produce certain neuronal subtypes; however, the upstream pathways that specify these progenitor fates remain unknown. To uncover the transcriptional networks that regulate Cux2 expression in the forebrain, we characterized a conserved Cux2 enhancer that recapitulates Cux2 expression specifically in the cortical hem. Using a bioinformatic approach, we identified putative transcription factor (TF)-binding sites for cortical hem-patterning TFs. We found that the homeobox TF Lmx1a can activate the Cux2 enhancer in vitro Furthermore, we showed that Lmx1a-binding sites were required for enhancer activity in the cortical hem in vivo Mis-expression of Lmx1a in hippocampal progenitors caused an increase in Cux2 enhancer activity outside the cortical hem. Finally, we compared several human enhancers with cortical hem-restricted activity and found that recurrent Lmx1a-binding sites are a top shared feature. Uncovering the network of TFs involved in regulating Cux2 expression will increase our understanding of the mechanisms pivotal in establishing Cux2 lineage fates in the developing forebrain.


Assuntos
Elementos Facilitadores Genéticos , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Homeodomínio/fisiologia , Íntrons , Proteínas com Homeodomínio LIM/fisiologia , Fatores de Transcrição/fisiologia , Animais , Sítios de Ligação , Linhagem da Célula , Biologia Computacional , Feminino , Proteínas de Homeodomínio/genética , Proteínas com Homeodomínio LIM/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Prosencéfalo/embriologia , Telencéfalo/embriologia , Fatores de Transcrição/genética
5.
Brain Struct Funct ; 224(1): 33-56, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30242506

RESUMO

Radial glial cells (RGCs) are the first cell populations of glial nature to appear during brain ontogeny. They act as primary progenitor (stem) cells as well as a scaffold for neuronal migration. The proliferative capacity of these cells, both in development and in adulthood, has been subject of interest during past decades. In contrast with mammals where RGCs are restricted to specific ventricular areas in the adult brain, RGCs are the predominant glial element in fishes. However, developmental studies on the RGCs of cartilaginous fishes are scant. We have studied the expression patterns of RGCs markers including glial fibrillary acidic protein (GFAP), brain lipid binding protein (BLBP), and glutamine synthase (GS) in the telencephalic hemispheres of catshark (Scyliorhinus canicula) from early embryos to post-hatch juveniles. GFAP, BLBP and GS are first detected, respectively, in early, intermediate and late embryos. Expression of these glial markers was observed in cells with radial glia morphology lining the telencephalic ventricles, as well as in their radial processes and endfeet at the pial surface and their expression continue in ependymal cells (or tanycytes) in early juveniles. In addition, BLBP- and GS-immunoreactive cells morphologically resembling oligodendrocytes were observed. In late embryos, most of the GFAP- and BLBP-positive RGCs also coexpress GS and show proliferative activity. Our results indicate the existence of different proliferating subpopulations of RGCs in the embryonic ventricular zone of catshark. Further investigations are needed to determine whether these proliferative RGCs could act as neurogenic and/or gliogenic precursors.


Assuntos
Células Ependimogliais/metabolismo , Proteína 7 de Ligação a Ácidos Graxos/metabolismo , Proteínas de Peixes/metabolismo , Proteína Glial Fibrilar Ácida/metabolismo , Glutamato-Amônia Ligase/metabolismo , Neurogênese , Tubarões/metabolismo , Telencéfalo/metabolismo , Fatores Etários , Animais , Animais Recém-Nascidos , Proliferação de Células , Embrião não Mamífero/metabolismo , Tubarões/embriologia , Tubarões/crescimento & desenvolvimento , Telencéfalo/embriologia , Telencéfalo/crescimento & desenvolvimento
6.
PLoS One ; 13(12): e0209369, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30571765

RESUMO

The full-length members of the Groucho/Transducin-like Enhancer of split gene family, namely Grg1-4, encode nuclear corepressors that act either directly, via interaction with transcription factors, or indirectly by modifying histone acetylation or chromatin structure. In this work we describe a detailed expression analysis of Grg1-4 family members during embryonic neurogenesis in the developing murine telencephalon. Grg1-4 presented a unique, complex yet overlapping expression pattern; Grg1 and Grg3 were mainly detected in the proliferative zones of the telencephalon, Grg2 mainly in the subpallium and finally, Grg4 mainly in the subpallial post mitotic neurons. In addition, comparative analysis of the expression of Grg1-4 revealed that, at these stages, distinct telencephalic progenitor domains or structures are characterized by the presence of different combinations of Grg repressors, thus forming a "Grg-mediated repression map".


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Neurogênese/genética , Mapas de Interação de Proteínas/fisiologia , Proteínas Repressoras/metabolismo , Telencéfalo/embriologia , Animais , Embrião não Mamífero , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Repressoras/genética
7.
Development ; 145(19)2018 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-30177526

RESUMO

Trio, a member of the Dbl family of guanine nucleotide exchange factors, activates Rac1 downstream of netrin 1/DCC signalling in axon outgrowth and guidance. Although it has been proposed that Trio also activates RhoA, the putative upstream factors remain unknown. Here, we show that Slit2 induces Trio-dependent RhoA activation, revealing a crosstalk between Slit and Trio/RhoA signalling. Consistently, we found that RhoA activity is hindered in vivo in T rio mutant mouse embryos. We next studied the development of the ventral telencephalon and thalamocortical axons, which have been previously shown to be controlled by Slit2. Remarkably, this analysis revealed that Trio knockout (KO) mice show phenotypes that bear strong similarities to the ones that have been reported in Slit2 KO mice in both guidepost corridor cells and thalamocortical axon pathfinding in the ventral telencephalon. Taken together, our results show that Trio induces RhoA activation downstream of Slit2, and support a functional role in ensuring the proper positioning of both guidepost cells and a major axonal tract. Our study indicates a novel role for Trio in Slit2 signalling and forebrain wiring, highlighting its role in multiple guidance pathways as well as in biological functions of importance for a factor involved in human brain disorders.


Assuntos
Padronização Corporal , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Fosfoproteínas/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Telencéfalo/embriologia , Telencéfalo/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo , Animais , Orientação de Axônios , Axônios/metabolismo , Embrião de Mamíferos/citologia , Fibroblastos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Cones de Crescimento/metabolismo , Fatores de Troca do Nucleotídeo Guanina/genética , Peptídeos e Proteínas de Sinalização Intercelular/genética , Camundongos Knockout , Modelos Biológicos , Proteínas do Tecido Nervoso/genética , Neurônios/metabolismo , Fosfoproteínas/genética , Proteínas Serina-Treonina Quinases/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Tálamo/embriologia , Tálamo/metabolismo
8.
J Neurosci ; 38(42): 9105-9121, 2018 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-30143575

RESUMO

Specification of dorsoventral regional identity in progenitors of the developing telencephalon is a first pivotal step in the development of the cerebral cortex and basal ganglia. Previously, we demonstrated that the two zinc finger doublesex and mab-3 related (Dmrt) genes, Dmrt5 (Dmrta2) and Dmrt3, which are coexpressed in high caudomedial to low rostrolateral gradients in the cerebral cortical primordium, are separately needed for normal formation of the cortical hem, hippocampus, and caudomedial neocortex. We have now addressed the role of Dmrt3 and Dmrt5 in controlling dorsoventral division of the telencephalon in mice of either sex by comparing the phenotypes of single knock-out (KO) with double KO embryos and by misexpressing Dmrt5 in the ventral telencephalon. We find that DMRT3 and DMRT5 act as critical regulators of progenitor cell dorsoventral identity by repressing ventralizing regulators. Early ventral fate transcriptional regulators expressed in the dorsal lateral ganglionic eminence, such as Gsx2, are upregulated in the dorsal telencephalon of Dmrt3;Dmrt5 double KO embryos and downregulated when ventral telencephalic progenitors express ectopic Dmrt5 Conditional overexpression of Dmrt5 throughout the telencephalon produces gene expression and structural defects that are highly consistent with reduced GSX2 activity. Further, Emx2;Dmrt5 double KO embryos show a phenotype similar to Dmrt3;Dmrt5 double KO embryos, and both DMRT3, DMRT5 and the homeobox transcription factor EMX2 bind to a ventral telencephalon-specific enhancer in the Gsx2 locus. Together, our findings uncover cooperative functions of DMRT3, DMRT5, and EMX2 in dividing dorsal from ventral in the telencephalon.SIGNIFICANCE STATEMENT We identified the DMRT3 and DMRT5 zinc finger transcription factors as novel regulators of dorsoventral patterning in the telencephalon. Our data indicate that they have overlapping functions and compensate for one another. The double, but not the single, knock-out produces a dorsal telencephalon that is ventralized, and olfactory bulb tissue takes over most remaining cortex. Conversely, overexpressing Dmrt5 throughout the telencephalon causes expanded expression of dorsal gene determinants and smaller olfactory bulbs. Furthermore, we show that the homeobox transcription factor EMX2 that is coexpressed with DMRT3 and DMRT5 in cortical progenitors cooperates with them to maintain dorsoventral patterning in the telencephalon. Our study suggests that DMRT3/5 function with EMX2 in positioning the pallial-subpallial boundary by antagonizing the ventral homeobox transcription factor GSX2.


Assuntos
Proteínas de Homeodomínio/fisiologia , Células-Tronco Neurais/fisiologia , Neurônios/fisiologia , Telencéfalo/embriologia , Fatores de Transcrição/fisiologia , Animais , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Homeodomínio/genética , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células-Tronco Neurais/metabolismo , Neurônios/metabolismo , Telencéfalo/metabolismo , Fatores de Transcrição/genética
9.
Stem Cell Res Ther ; 9(1): 67, 2018 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-29544541

RESUMO

BACKGROUND: Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) have been widely used to generate cellular models harboring specific disease-related genotypes. Of particular importance are ESC and iPSC applications capable of producing dorsal telencephalic neural progenitor cells (NPCs) that are representative of the cerebral cortex and overcome the challenges of maintaining a homogeneous population of cortical progenitors over several passages in vitro. While previous studies were able to derive NPCs from pluripotent cell types, the fraction of dorsal NPCs in this population is small and decreases over several passages. Here, we present three protocols that are highly efficient in differentiating mouse and human ESCs, as well as human iPSCs, into a homogeneous and stable population of dorsal NPCs. These protocols will be useful for modeling cerebral cortical neurological and neurodegenerative disorders in both mouse and human as well as for high-throughput drug screening for therapeutic development. METHODS: We optimized three different strategies for generating dorsal telencephalic NPCs from mouse and human pluripotent cell types through single or double inhibition of bone morphogenetic protein (BMP) and/or SMAD pathways. Mouse and human pluripotent cells were aggregated to form embryoid bodies in suspension and were treated with dorsomorphin alone (BMP inhibition) or combined with SB431542 (double BMP/SMAD inhibition) during neural induction. Neural rosettes were then selected from plated embryoid bodies to purify the population of dorsal NPCs. We tested the expression of key dorsal NPC markers as well as nonectodermal markers to confirm the efficiency of our three methods in comparison to published and commercial protocols. RESULTS: Single and double inhibition of BMP and/or SMAD during neural induction led to the efficient differentiation of dorsal NPCs, based on the high percentage of PAX6-positive cells and the NPC gene expression profile. There were no statistically significant differences in the variation of PAX6 and SOX1-positive NPCs between the two human pluripotent cell-derived methods; therefore, both methods are suitable for producing stable dorsal NPCs. When further differentiated into mature neurons, NPCs gave rise to a population of almost exclusively forebrain cortical neurons, confirming the dorsal fate commitment of the progenitors. CONCLUSIONS: The methods described in this study show improvements over previously published studies and are highly efficient at differentiating human and mouse pluripotent cell types into dorsal PAX6-positive NPCs and eventually into forebrain cortical neurons.


Assuntos
Células-Tronco Embrionárias Humanas/citologia , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Neurais/citologia , Cultura Primária de Células/métodos , Animais , Células Cultivadas , Humanos , Camundongos , Telencéfalo/citologia , Telencéfalo/embriologia
10.
Development ; 145(1)2018 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-29229772

RESUMO

During forebrain development, a telencephalic organizer called the cortical hem is crucial for inducing hippocampal fate in adjacent cortical neuroepithelium. How the hem is restricted to its medial position is therefore a fundamental patterning issue. Here, we demonstrate that Foxg1-Lhx2 interactions are crucial for the formation of the hem. Loss of either gene causes a region of the cortical neuroepithelium to transform into hem. We show that FOXG1 regulates Lhx2 expression in the cortical primordium. In the absence of Foxg1, the presence of Lhx2 is sufficient to suppress hem fate, and hippocampal markers appear selectively in Lhx2-expressing regions. FOXG1 also restricts the temporal window in which loss of Lhx2 results in a transformation of cortical primordium into hem. Therefore, Foxg1 and Lhx2 form a genetic hierarchy in the spatiotemporal regulation of cortical hem specification and positioning, and together ensure the normal development of this hippocampal organizer.


Assuntos
Fatores de Transcrição Forkhead/biossíntese , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Hipocampo/embriologia , Proteínas com Homeodomínio LIM/biossíntese , Proteínas do Tecido Nervoso/biossíntese , Telencéfalo/embriologia , Fatores de Transcrição/biossíntese , Animais , Fatores de Transcrição Forkhead/genética , Proteínas com Homeodomínio LIM/genética , Camundongos , Camundongos Transgênicos , Proteínas do Tecido Nervoso/genética , Fatores de Transcrição/genética
11.
Toxicol Lett ; 284: 113-119, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29248573

RESUMO

Bisphenol A (BPA) is a widely used compound in the food packaging industry. Prenatal exposure to BPA induces histological abnormalities in the neocortex and hypothalamus in association with abnormal behaviors. Yet, the molecular and cellular neurodevelopmental toxicological mechanisms of BPA are incompletely characterized on neuroinflammatory-related endopoints. To evaluate the neurodevelopmental effects of BPA exposure in mouse embryos, we examined microglial numbers as well as the expression of microglial-related factors in the E15.5 embryonic brain. BPA-exposed embryos exhibited significant increases in Iba1-immunoreactive microglial numbers in the dorsal telencephalon and the hypothalamus compared to control embryos. Further, the expression levels of microglial markers (Iba1, CD16, iNOS, and CD206), inflammatory factors (TNFα and IL4), signal transducing molecules (Cx3Cr1 and Cx3Cl1), and neurotrophic factor (IGF1) were altered in BPA-exposed embryos. These findings suggest that BPA exposure increases microglial numbers in the brain and alters the neuroinflammatory status at a transcriptional level. Together, these changes may represent a novel target for neurodevelopmental toxicity assessment after BPA exposure.


Assuntos
Compostos Benzidrílicos/toxicidade , Poluentes Ambientais/toxicidade , Hipotálamo/efeitos dos fármacos , Microglia/efeitos dos fármacos , Fenóis/toxicidade , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Telencéfalo/efeitos dos fármacos , Animais , Comportamento Animal/efeitos dos fármacos , Biomarcadores/análise , Contagem de Células , Relação Dose-Resposta a Droga , Feminino , Embalagem de Alimentos , Expressão Gênica/efeitos dos fármacos , Hipotálamo/embriologia , Mediadores da Inflamação/imunologia , Masculino , Camundongos Endogâmicos ICR , Microglia/imunologia , Microglia/metabolismo , Microglia/patologia , Neurogênese/efeitos dos fármacos , Gravidez , Efeitos Tardios da Exposição Pré-Natal/imunologia , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Efeitos Tardios da Exposição Pré-Natal/patologia , Telencéfalo/embriologia
12.
Dev Dyn ; 247(1): 222-228, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28744915

RESUMO

BACKGROUND: The lateral ganglionic eminence (LGE) in the ventral telencephalon is a diverse progenitor domain subdivided by distinct gene expression into a dorsal region (dLGE) that gives rise to olfactory bulb and amygdalar interneurons and a ventral region (vLGE) that gives rise to striatal projection neurons. The homeobox gene, Gsx2, is an enriched marker of the LGE and is expressed in a high dorsal to low ventral gradient in the ventricular zone (VZ) as development proceeds. Aside from Gsx2, markers restricted to the VZ in the dLGE and/or vLGE remain largely unknown. RESULTS: Here, we show that the gene and protein expression of Glucocorticoid-induced transcript 1 (Glcci1) has a similar dorsal to ventral gradient of expression in the VZ as Gsx2. We found that Glcci1 gene and protein expression are reduced in Gsx2 mutants, and are increased in the cortex after early and late Gsx2 misexpression. Moreover, Glcci1 expressing cells are restricted to a subpopulation of Gsx2 positive cells on the basal side of the VZ and co-express Ascl1, but not the subventricular zone dLGE marker, Sp8. CONCLUSIONS: These findings suggest that Glcci1 is a new marker of a subpopulation of LGE VZ progenitor cells in the Gsx2 lineage. Developmental Dynamics 247:222-228, 2018. © 2017 Wiley Periodicals, Inc.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Células-Tronco Neurais/metabolismo , Receptores de Glucocorticoides/metabolismo , Telencéfalo/metabolismo , Animais , Camundongos , Camundongos Transgênicos , Neurônios/metabolismo , Receptores de Glucocorticoides/genética , Telencéfalo/embriologia
13.
Neural Dev ; 12(1): 19, 2017 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-29141678

RESUMO

Patterning of the telencephalic neuroepithelium is a tightly regulated process controlled by transcription factors and signalling molecules. The cortical primordium is flanked by two signalling centres, the hem medially, and the antihem laterally. The hem induces the formation of the hippocampus in adjacent neuroepithelium. Therefore, the position of the hem defines the position of the hippocampus in the brain. The antihem is positioned at the boundary between the dorsal and ventral telencephalon and proposed to provide patterning cues during development. LIM-homeodomain (LIM-HD) transcription factor LHX2 suppresses both hem and antihem fate in the cortical neuroepithelium. Upon loss of Lhx2, medial cortical neuroepithelium is transformed into hem, whereas lateral cortical neuroepithelium is transformed into antihem. Here, we show that transcription factor PAX6, known to regulate patterning of the lateral telencephalon, restricts this tissue from transforming into hem upon loss of Lhx2. When Lhx2 and Pax6 are both deleted, the cortical hem expands to occupy almost the complete extent of the cortical primordium, indicating that both factors act to suppress hem fate in the lateral telencephalon. Furthermore, the shift in the pallial-subpallial boundary and absence of the antihem, observed in the Pax6 mutant, are both restored in the Lhx2; Pax6 double mutant. Together, these results not only reveal a novel function for LHX2 in regulating dorsoventral patterning in the telencephalon, but also identify PAX6 as a fundamental regulator of where the hem can form, and therefore implicate this molecule as a determinant of hippocampal positioning.


Assuntos
Proteínas com Homeodomínio LIM/deficiência , Neurogênese/fisiologia , Fator de Transcrição PAX6/deficiência , Telencéfalo/embriologia , Fatores de Transcrição/deficiência , Animais , Camundongos , Camundongos Knockout
14.
Dev Growth Differ ; 59(9): 701-712, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29124740

RESUMO

The anterior part of the embryonic telencephalon gives rise to several brain regions that are important for animal behavior, including the frontal cortex (FC) and the olfactory bulb. The FC plays an important role in decision-making behaviors, such as social and cognitive behavior, and the olfactory bulb is involved in olfaction. Here, we show the organizing activity of fibroblast growth factor 8 (Fgf8) in the regionalization of the anterior telencephalon, specifically the FC and the olfactory bulb. Misexpression of Fgf8 in the most anterior part of the mouse telencephalon at embryonic day 11.5 (E11.5) by ex utero electroporation resulted in a lateral shift of dorsal FC subdivision markers and a lateral expansion of the dorsomedial part of the FC, the future anterior cingulate and prelimbic cortex. Fgf8-transfected brains had lacked ventral FC, including the future orbital cortex, which was replaced by the expanded olfactory bulb. The olfactory region occupied a larger area of the FC when transfection efficiency of Fgf8 was higher. These results suggest that Fgf8 regulates the proportions of the FC and olfactory bulb in the anterior telencephalon and has a medializing effect on the formation of FC subdivisions.


Assuntos
Fator 8 de Crescimento de Fibroblasto/metabolismo , Telencéfalo/metabolismo , Animais , Córtex Cerebral/embriologia , Córtex Cerebral/metabolismo , Fator 8 de Crescimento de Fibroblasto/genética , Fatores de Crescimento de Fibroblastos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Camundongos , Bulbo Olfatório/embriologia , Bulbo Olfatório/metabolismo , Telencéfalo/embriologia
15.
Biochem Biophys Res Commun ; 493(4): 1560-1566, 2017 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-28974418

RESUMO

Neuronal nitric oxide synthase (nNOS) 1, mainly responsible for NO release in central nervous system (CNS) 2, plays a significant role in multiple physiological functions. However, the function of nNOS+ interneurons in fear learning has not been much explored. Here we focused on the medial ganglionic eminences (MGE) 3-derived nNOS+ interneurons in fear learning. To determine the origin of nNOS+ interneurons, we cultured neurons in vitro from MGE, cortex, lateral ganglionic eminence (LGE) 4, caudal ganglionic eminences (CGE) 5 and preoptic area (POA) 6. The results showed that MGE contained the most abundant precursors of nNOS+ interneurons. Moreover, donor cells from E12.5 embryos demonstrated the highest positive rate of nNOS+ interneurons compared with other embryonic periods (E11.5, E12, E13, E13.5 and E14). Additionally, these cells from E12.5 embryos showed long axonal and abundant dendritic arbors after 10 days culture, indicating the capability to disperse and integrate in host neural circuits after transplantation. To investigate the role of MGE-derived nNOS+ interneurons in fear learning, donor MGE cells were transplanted into dentate gyrus (DG) 7 of nNOS knock-out (nNOS-/-) or wild-type mice. Results showed that the transplantation of MGE cells promoted the acquisition of nNOS-/- but not the wild-type mice, suggesting the importance of nNOS+ neurons in fear acquisition. Moreover, we transplanted MGE cells from nNOS-/- mice or wild-type mice into DG of the nNOS-/- mice and found that only MGE cells from wild-type mice but not the nNOS-/- mice rescued the deficit in acquisition of the nNOS-/- mice, further confirming the positive role of nNOS+ neurons in fear learning.


Assuntos
Medo/fisiologia , Interneurônios/fisiologia , Eminência Mediana/fisiologia , Óxido Nítrico Sintase Tipo I/fisiologia , Animais , Comportamento Animal/fisiologia , Células Cultivadas , Giro Denteado/citologia , Giro Denteado/fisiologia , Giro Denteado/cirurgia , Interneurônios/citologia , Interneurônios/transplante , Aprendizagem/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Células-Tronco Neurais/citologia , Células-Tronco Neurais/fisiologia , Células-Tronco Neurais/transplante , Óxido Nítrico Sintase Tipo I/deficiência , Óxido Nítrico Sintase Tipo I/genética , Telencéfalo/citologia , Telencéfalo/embriologia
16.
Dev Biol ; 431(2): 168-178, 2017 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-28941984

RESUMO

Development of the brain directly influences the development of the face via both physical growth and Sonic hedgehog (SHH) activity; however, little is known about how neural crest cells (NCCs), the mesenchymal population that comprise the developing facial prominences, influence the development of the brain. We utilized the conditional ciliary mutant Wnt1-Cre;Kif3afl/fl to demonstrate that loss of primary cilia on NCCs resulted in a widened ventral forebrain. We found that neuroectodermal Shh expression, dorsal/ventral patterning, and amount of proliferation in the ventral neuroectoderm was not changed in Wnt1-Cre;Kif3afl/fl mutants; however, tissue polarity and directional cell division were disrupted. Furthermore, NCCs of Wnt1-Cre;Kif3afl/fl mutants failed to respond to a SHH signal emanating from the ventral forebrain. We were able to recapitulate the ventral forebrain phenotype by removing Smoothened from NCCs (Wnt1-Cre;Smofl/fl) indicating that changes in the ventral forebrain were mediated through a Hedgehog-dependent mechanism. Together, these data suggest a novel, cilia-dependent mechanism for NCCs during forebrain development.


Assuntos
Divisão Celular , Cílios/metabolismo , Proteínas Hedgehog/metabolismo , Morfogênese , Crista Neural/citologia , Prosencéfalo/citologia , Prosencéfalo/embriologia , Animais , Padronização Corporal/genética , Polaridade Celular , Face/embriologia , Regulação da Expressão Gênica no Desenvolvimento , Integrases/metabolismo , Cinesina/metabolismo , Camundongos , Modelos Biológicos , Morfogênese/genética , Mutação/genética , Crista Neural/metabolismo , Placa Neural/citologia , Placa Neural/embriologia , Placa Neural/metabolismo , Fenótipo , Prosencéfalo/metabolismo , Recombinação Genética/genética , Fatores de Transcrição SOXE/metabolismo , Telencéfalo/embriologia , Telencéfalo/metabolismo , Proteínas Wnt/metabolismo
17.
Autophagy ; 13(8): 1348-1363, 2017 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-28598226

RESUMO

Interneuron progenitors in the ganglionic eminence of the ventral telencephalon generate most cortical interneurons during brain development. However, the regulatory mechanism of interneuron progenitors remains poorly understood. Here, we show that MTOR (mechanistic target of rapamycin [serine/threonine kinase]) regulates proliferation and macroautophagy/autophagy of interneuron progenitors in the developing ventral telencephalon. To investigate the role of MTOR in interneuron progenitors, we conditionally deleted the Mtor gene in mouse interneuron progenitors and their progeny by using Tg(mI56i-cre,EGFP)1Kc/Dlx5/6-Cre-IRES-EGFP and Nkx2-1-Cre drivers. We found that Mtor deletion markedly reduced the number of interneurons in the cerebral cortex. However, relative positioning of cortical interneurons was normal, suggesting that disruption of progenitor self-renewal caused the decreased number of cortical interneurons in the Mtor-deleted brain. Indeed, Mtor-deleted interneuron progenitors showed abnormal proliferation and cell cycle progression. Additionally, we detected a significant activation of autophagy in Mtor-deleted brain. Our findings suggest that MTOR plays a critical role in the regulation of cortical interneuron number and autophagy in the developing brain.


Assuntos
Autofagia , Encéfalo/citologia , Encéfalo/embriologia , Neurônios GABAérgicos/citologia , Interneurônios/citologia , Serina-Treonina Quinases TOR/metabolismo , Animais , Contagem de Células , Ciclo Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Proteína Forkhead Box O3/metabolismo , Neurônios GABAérgicos/efeitos dos fármacos , Neurônios GABAérgicos/metabolismo , Deleção de Genes , Integrases/metabolismo , Interneurônios/efeitos dos fármacos , Interneurônios/metabolismo , Camundongos Transgênicos , Modelos Biológicos , Tamanho do Órgão , Sirolimo/farmacologia , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Serina-Treonina Quinases TOR/antagonistas & inibidores , Telencéfalo/citologia , Telencéfalo/embriologia
18.
Dev Growth Differ ; 59(4): 258-269, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28581027

RESUMO

Among the forkhead box protein family, Foxg1 is a unique transcription factor that plays pleiotropic and non-redundant roles in vertebrate brain development. The emergence of the telencephalon at the rostral end of the neural tube and its subsequent expansion that is mediated by Foxg1 was a key reason for the vertebrate brain to acquire higher order information processing, where Foxg1 is repetitively used in the sequential events of telencephalic development to control multi-steps of brain circuit formation ranging from cell cycle control to neuronal differentiation in a clade- and species-specific manner. The objective of this review is to discuss how the evolutionary changes in cis- and trans-regulatory network that is mediated by a single transcription factor has contributed to determining the fundamental vertebrate brain structure and its divergent roles in instructing species-specific neuronal circuitry and functional specialization.


Assuntos
Encéfalo/embriologia , Fatores de Transcrição Forkhead/metabolismo , Telencéfalo/embriologia , Animais , Encéfalo/metabolismo , Fatores de Transcrição Forkhead/genética , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Neurogênese/fisiologia , Telencéfalo/metabolismo
19.
Dev Growth Differ ; 59(4): 175-187, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28470718

RESUMO

In the current model, the most anterior part of the forebrain (secondary prosencephalon) is subdivided into the telencephalon dorsally and the hypothalamus ventrally. Our recent study identified a new morphogenetic unit named the optic recess region (ORR) between the telencephalon and the hypothalamus. This modification of the forebrain regionalization based on the ventricular organization resolved some previously unexplained inconsistency about regional identification in different vertebrate groups. The ventricular-based comparison also revealed a large diversity within the subregions (notably in the hypothalamus and telencephalon) among different vertebrate groups. In tetrapods there is only one hypothalamic recess, while in teleosts there are two recesses. Most notably, the mammalian and teleost hypothalami are two extreme cases: the former has lost the cerebrospinal fluid-contacting (CSF-c) neurons, while the latter has increased them. Thus, one to one homology of hypothalamic subregions in mammals and teleosts requires careful verification. In the telencephalon, different developmental processes between Sarcopterygii (lobe-finned fish) and Actinopterygii (ray-finned fish) have already been described: the evagination and the eversion. Although pallial homology has been long discussed based on the assumption that the medial-lateral organization of the pallium in Actinopterygii is inverted from that in Sarcopterygii, recent developmental data contradict this assumption. Current models of the brain organization are largely based on a mammalian-centric point of view, but our comparative analyses shed new light on the brain organization of Osteichthyes.


Assuntos
Peixes/embriologia , Telencéfalo/embriologia , Animais , Neurogênese/fisiologia , Prosencéfalo/embriologia
20.
J Neurosci ; 37(23): 5690-5698, 2017 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-28483978

RESUMO

FGF signaling, an important component of intercellular communication, is required in many tissues throughout development to promote diverse cellular processes. Whether FGF receptors (FGFRs) accomplish such varied tasks in part by activating different intracellular transducers in different contexts remains unclear. Here, we used the developing mouse telencephalon as an example to study the role of the FRS adapters FRS2 and FRS3 in mediating the functions of FGFRs. Using tissue-specific and germline mutants, we examined the requirement of Frs genes in two FGFR-dependent processes. We found that Frs2 and Frs3 are together required for the differentiation of a subset of medial ganglionic eminence (MGE)-derived neurons, but are dispensable for the survival of early telencephalic precursor cells, in which any one of three FGFRs (FGFR1, FGFR2, or FGFR3) is sufficient for survival. Although FRS adapters are dispensable for ERK-1/2 activation, they are required for AKT activation within the subventricular zone of the developing MGE. Using an FRS2,3-binding site mutant of Fgfr1, we established that FRS adapters are necessary for mediating most or all FGFR1 signaling, not only in MGE differentiation, but also in cell survival, implying that other adapters mediate at least in part the signaling from FGFR2 and FGFR3. Our study provides an example of a contextual role for an intracellular transducer and contributes to our understanding of how FGF signaling plays diverse developmental roles.SIGNIFICANCE STATEMENT FGFs promote a range of developmental processes in many developing tissues and at multiple developmental stages. The mechanisms underlying this multifunctionality remain poorly defined in vivo Using telencephalon development as an example, we show here that FRS adapters exhibit some selectivity in their requirement for mediating FGF receptor (FGFR) signaling and activating downstream mediators that depend on the developmental process, with a requirement in neuronal differentiation but not cell survival. Differential engagement of FRS and non-FRS intracellular adapters downstream of FGFRs could therefore in principle explain how FGFs play several distinct roles in other developing tissues and developmental stages.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Fatores de Crescimento de Fibroblastos/metabolismo , Células-Tronco Neurais/metabolismo , Receptores de Fatores de Crescimento de Fibroblastos/metabolismo , Telencéfalo/embriologia , Telencéfalo/metabolismo , Animais , Sobrevivência Celular/fisiologia , Células Cultivadas , Feminino , Masculino , Camundongos , Camundongos Transgênicos , Células-Tronco Neurais/citologia , Telencéfalo/citologia
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