Este trabalho foi financiado pelo Instituto Nacional para a Saúde Mental, e da National Science Foundation. Agradecimentos especiais a membros do laboratório SIVE para muitas discussões úteis e críticas construtivas, e para Olivier Paugois para criação de peixes especialista.

1. Preparando-se para microinjeção <ol><li> Prepare agulhas microinjeção puxando tubos capilares utilizando Sutter extrator agulha instrumentos. </li><li> Agulha de microinjecção de carga com corante fluorescente (FITC-dextrano). </li><li> Montar a agulha no aparelho micromanipulador e microinjecção. </li><li> Cuidadosamente quebrar agulha microinjeção usando uma pinça para cerca de 2 m de largura, no entanto, isso vai variar dependendo da configuração do microinjetor. Para agulhas nossos microinjecção, esta corresponde à primeira região da agulha a partir da ponta, que não se curva. </li><li> Medir o tamanho da gota de óleo, ajustando o tempo de injecção e pressão, de modo que cada um proporciona uma injecção nl. Definições de exemplo para Harvard Apparatus microinjetor são: P = 1,4 psi equilíbrio, P = 1,4 psi fora, P = 22,9 psi injetar, P = 67,8 psi claras com um tempo de injeção de 0,4-0,7 seg. O diâmetro da nossa agulha usando essas configurações é de aproximadamente 2 m. No entanto, as definições serão microinjetor específico, e variamegundo a agulha de diâmetro. </li></ol> 2. Preparando os embriões <ol><li> Revestimento de dois pratos com agarose a 1% em água, para cada condição, furos puxão em agarose com uma ponta de pipeta de 1-200 uL, e remover tampões de agarose. Preencha pratos com a mídia de embriões. </li><li> Usando pinça, embriões dechorionate que são 18 hpf ou mais sob estereomicroscópio. Embriões são encenadas de acordo com Kimmel et al. 11. </li><li> Transferência de embriões dechorionated no prato agarose primeiro revestido. </li><li> Para anestesiar os embriões, adicionar tricaina (0,1 mg / ml) para o prato até embriões parar de se mover (feito de acordo com Westerfield 12). </li></ol> 3. Injetando os ventrículos cerebrais <ol><li> Embriões orientar para que você está olhando para o seu lado dorsal, colocando a cauda do embrião dentro do buraco. Se o micromanipulador está do lado direito, em seguida, deslocar o embrião de modo que o prosencéfalo é para a esquerda e para a direita rombencéfalo. </li><li> Posição da agulha ao widest ponto de ventrículo rombencéfalo. </li><li> Cuidadosamente placa telhado perfurar do ventrículo rombencéfalo tendo a certeza de não passar a profundidade do cérebro para a gema (Figura 1A). </li><li> Injectar 1-2 nl de corante fluorescente para os ventrículos, certificando-se que o corante enche todo o comprimento dos ventrículos do cérebro. </li><li> Transferir os embriões para o prato agarose segundo revestido cheio com meios de embriões e re-anestesiar como descrito em 2.4. </li><li> Começar imediatamente a imagem, como descrito na seção 4, a fim de obter uma imagem tempo zero. </li></ol> 4. Imagem <ol><li> Embriões orientar com sua cauda no buraco, como descrito em 3.1. </li><li> Use um microscópio de dissecação com luz fluorescente e transmitida tanto para obter uma imagem dorsal campo claro. Mantenha a ampliação constante entre imagiologia de embriões diferentes. Isto permite a comparação direta de análises realizadas utilizando Image J (5,2-6). </li><li> Sem mover o embrião microscópio, ou prato, dê umaimagem fluorescente correspondente. </li><li> Repetir para cada embrião em pontos de tempo desejados. </li></ol> 5. Quantificação de Movimento Dye <ol><li> Fundir de campo claro e as imagens fluorescentes em Photoshop como anteriormente descrito por Gutzman e Sive 10. </li><li> Medir a distância os movimentos frente de corante no software Image J disponível em <a href="http://rsbweb.nih.gov/ij/" target="_blank">http://rsbweb.nih.gov/ij/</a> . </li><li> Arquivo mesclado aberto no Image J e use a ferramenta de linha para desenhar uma linha do prosencéfalo dobradiça ponto-a-tingir frente em um ângulo de 10-20 ° de neuroepitélio (Figura 1A). Esta região foi escolhida por ser o primeiro local e mais notável de corante vazar do neuroepitélio de tipo selvagem. </li><li> Selecione a ferramenta de medição para calcular o comprimento da linha. </li><li> Repetir para cada ponto do tempo. </li><li> Calcular a distância a frente de corante líquido movido ao longo do tempo, subtraindo a distância em t = 0 a partir de outros pontos de tempo. </li><li> Lote emgráfico. </li></ol> 6. Resultados representativos Um exemplo dos resultados obtidos num ensaio de permeabilidade utilizando embriões neuroepitelial do tipo selvagem é mostrada na Figura 1B, D-. Para diferenciar com precisão da permeabilidade, que é útil para testar os corantes com weightsto molecular diferente identificar um tamanho que é apenas ligeiramente permeável de tipo selvagem ou de embriões de controlo (Figura 2). Isto permite a identificação de mutantes genéticos ou condições ambientais que, ou aumento ou diminuição de permeabilidade (Figura 1D, verde e vermelho, respectivamente, de linhas). Para o neuroepitélio zebrafish 24 hpf, 70 kDa vazamentos FITC Dextran lentamente ao longo de 2 horas, enquanto 2.000 kDa não faz e 10 kDa quase imediatamente vaza. Portanto 70 kDa é o peso ideal molecular para identificar as condições que tanto aumentar e diminuir a permeabilidade neuroepitelial. Se a agulha falha do lúmen do ventrículo, a fluorescência wmal aparecem fora do cérebro em t = 0 (para um exemplo veja Gutzman e Sive, 2009 10). Estes embriões devem ser eliminados uma vez que a tinta não foi injectado inicialmente contido no interior do cérebro e nenhuma conclusão clara sobre o movimento do corante e permeabilidade da neuropeithelium podem ser feitas. Finalmente, se os embriões têm ventrículos pequenos ou ventrículos cerebrais un-inflados, pré-injecção dos ventrículos com uma solução salina pode ser feito antes da injecção do corante fluorescente. Isto faz a insuflação dos ventrículos tornando visualização posterior dos ventrículos mais fácil quando se injecta com o corante fluorescente. Controlos apropriados devem ser realizados para determinar se a injecção de uma solução salina normal, interrompe o desenvolvimento do tubo neural. <img alt="Figura 1" src="/files/ftp_upload/4242/4242fig1.jpg" /> Figura 1. Curso de tempo de diferentes corantes de peso molecular. (A) Diagrama Experimental. Primeiro, Corante fluorescente é injetado nos ventrículos. X = posição de agulha para injecção. Próxima imagens dorsais são capturados ao longo do tempo. Finalmente, a distância percorrida pela frente do corante a partir do prosencéfalo dobradiça ponto é medida (representada por uma linha vermelha). (BC) Incorporada campo claro e fluorescentes imagens dorsal a 22 hpf (t = 0 min, B) e 24 hpf (t = 120 min, C). Linha branca indica a distância da frente de corante do cérebro anterior do ventrículo. (D) de dados de permeabilidade hipotéticos amostra. Azul = tipo selvagem ou controles, vermelho = amostra com permeabilidade diminuiu em relação ao controle, e amostra verde = com permeabilidade aumentada em relação ao controle. <img alt="Figura 2" src="/files/ftp_upload/4242/4242fig2.jpg" /> Figura 2. Medição da permeabilidade de diferentes corantes neuroepitelial peso molecular. (AE) brightfield Dorsal resultante da fusão e as imagens fluorescentes de 22 HPF embriões de tipo selvagem em t = 0 min após a injecção, com FITC-dExtran dos pesos moleculares seguintes: 10 kDa (A), 40 kDa (B), 70 kDa (C), 500 kDa (D) e de 2.000 kDa (E). (A&#39;-E &#39;) O mesmo que no embrião (AE) em t = 120 min a 24 hpf. Anterior para a esquerda. F = prosencéfalo, M = mesencéfalo, H = rombencéfalo. Asterisco = orelha.

<ol>
	<li>Harrington, M. J., Hong, E., Brewster, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+analysis+of+neurulation:+first+impressions+do+not+count.">Comparative analysis of neurulation: first impressions do not count.</a> Mol. Reprod. Dev. 76, 954-965 (2009).</li><li>Lowery, L. A., Sive, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strategies+of+vertebrate+neurulation+and+a+re-evaluation+of+teleost+neural+tube+formation.">Strategies of vertebrate neurulation and a re-evaluation of teleost neural tube formation.</a> Mech. Dev. 121, 1189-1197 (2004).</li><li>Salehi, Z., Mashayekhi, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+cerebrospinal+fluid+on+neural+cell+survival+in+the+developing+chick+cerebral+cortex:+an+in+vivo+study.">The role of cerebrospinal fluid on neural cell survival in the developing chick cerebral cortex: an in vivo study.</a> Eur. J. Neurol. 13, 760-764 (2006).</li><li>Martin, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+embryonic+brain+development+in+rats+requires+the+trophic+influence+of+cerebrospinal+fluid.">Early embryonic brain development in rats requires the trophic influence of cerebrospinal fluid.</a> Int. J. Dev. Neurosci. 27, 733-740 (2009).</li><li>Lehtinen, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+cerebrospinal+fluid+provides+a+proliferative+niche+for+neural+progenitor+cells.">The cerebrospinal fluid provides a proliferative niche for neural progenitor cells.</a> Neuron. 69, 893-905 (2011).</li><li>Gato, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Embryonic+cerebrospinal+fluid+regulates+neuroepithelial+survival,+proliferation,+and+neurogenesis+in+chick+embryos.">Embryonic cerebrospinal fluid regulates neuroepithelial survival, proliferation, and neurogenesis in chick embryos.</a> Anat. Rec. A. Discov. Mol. Cell Evol. Biol. 284, 475-484 (2005).</li><li>Lowery, L. A., Sive, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Totally+tubular:+the+mystery+behind+function+and+origin+of+the+brain+ventricular+system.">Totally tubular: the mystery behind function and origin of the brain ventricular system.</a> Bioessays. 31, 446-458 (2009).</li><li>Lowery, L. A., Sive, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Initial+formation+of+zebrafish+brain+ventricles+occurs+independently+of+circulation+and+requires+the+nagie+oko+and+snakehead/atp1a1a.1+gene+products.">Initial formation of zebrafish brain ventricles occurs independently of circulation and requires the nagie oko and snakehead/atp1a1a.1 gene products.</a> Development. 132, 2057-2067 (2005).</li><li>Zhang, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Establishment+of+a+neuroepithelial+barrier+by+Claudin5a+is+essential+for+zebrafish+brain+ventricular+lumen+expansion.">Establishment of a neuroepithelial barrier by Claudin5a is essential for zebrafish brain ventricular lumen expansion.</a> Proc. Natl. Acad. Sci. U.S.A. 107, 1425-1430 (2010).</li><li>Gutzman, J. H., Sive, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+brain+ventricle+injection.">Zebrafish brain ventricle injection.</a> J. Vis. Exp. , (2009).</li><li>Kimmel, C. B., Ballard, W. W., Kimmel, S. R., Ullmann, B., Schilling, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stages+of+embryonic+development+of+the+zebrafish.">Stages of embryonic development of the zebrafish.</a> Dev. Dyn. 203, 253-310 (1995).</li><li>Westerfield, M., Sprague, J., Doerry, E., Douglas, S., Grp, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Zebrafish+Information+Network+(ZFIN):+a+resource+for+genetic,+genomic+and+developmental+research.">The Zebrafish Information Network (ZFIN): a resource for genetic, genomic and developmental research.</a> Nucleic Acids Research. 29, 87-90 (2001).</li></ol>

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Nós demonstrar a capacidade de quantificar a permeabilidade do cérebro embrionário do peixe-zebra vivos, tal como determinado por um corante injectado de um determinado peso molecular. A nossa observação de que o neuroepitélio zebrafish embrionária é diferencialmente permeável aos corantes de diferentes pesos moleculares sugere que o corante está a avançar através da permeabilidade paracelular. No entanto, não podemos descartar a possibilidade de uma contribuição para a permeabilidade transcelular observado. Esta técnica pode ser aplicada a qualquer outra estrutura tubular, enquanto o interior eo exterior do tubo pode ser visto e o lúmen pode ser injectada. No entanto, a identificação do peso molecular ideal para outros órgãos terá de ser determinado como este pode diferir entre os tecidos e estádios de desenvolvimento. Este ensaio vai permitir uma investigação mais aprofundada sobre o papel da permeabilidade epitelial durante lúmen inflação ea regulação do tamanho do lúmen. Além disso, esta técnica vai elelp caracterizar as alterações na permeabilidade epitelial associada a perturbações tais como a hidrocefalia e doença poliquística do rim.

<table border="1"><tbody><tr><td> Nome do reagente </td><td> Companhia </td><td> Número de catálogo </td></tr><tr><td> Dextrano, fluoresceína, Anionic, Lisina fixável </td><td> Invitrogen </td><td> D7136, D7137, D1822, D1820, D1845 </td></tr><tr><td> Tricaina pó </td><td> Sigma </td><td> A5040 </td></tr><tr><td> Tubos capilares </td><td> FHC Inc. </td><td> 30-30-1 </td></tr></tbody></table>

an assay for permeability of the zebrafish embryonic neuroepithelium

O sistema ventricular do cérebro é conservada entre vertebrados e é composto de uma série de cavidades interconectadas chamado ventrículos cerebrais, os quais formam, durante as primeiras fases do desenvolvimento do cérebro e são mantidas durante toda a vida do animal. O sistema ventricular do cérebro é encontrado em vertebrados, e os ventrículos se desenvolver após a formação do tubo neural, em que o lúmen central, enche-se de líquido cefalorraquidiano (LCR) 1,2. CSF é um líquido rico em proteínas que são essenciais para o desenvolvimento do cérebro e função normais 3-6. No peixe-zebra, o cérebro de inflação ventrículo começa em cerca de 18 a fertilização pós hr (hpf), depois de o tubo neural está fechado. Vários processos estão associados com a formação de cérebro ventricular, incluindo a formação de um neuroepitélio, a formação da junção estanque, que regula a produção de permeabilidade e CSF. Nós mostramos que o Na, K-ATPase é necessária para a inflação do ventrículo cerebral, afectando todos estes processoses 7,8, ao passo 5a claudina é necessário para a formação da junção estanque 9. Além disso, mostramos que a &quot;relaxamento&quot; do neuroepitélio embrionário, através da inibição da miosina, está associada com a inflação do ventrículo cerebral. Para investigar a regulação da permeabilidade durante zebrafish inflação ventrículo cerebral, foi desenvolvido um ensaio ventricular retenção de corante. Este método utiliza a injecção ventrículo cerebral em um embrião do peixe-zebra vivos, uma técnica anteriormente desenvolvido no nosso laboratório 10, a fluorescência rotular o fluido cerebrospinal. Os embriões são então trabalhada ao longo do tempo à medida que o corante fluorescente, através dos ventrículos cerebrais e neuroepitélio. A distância da frente de corante se afasta do basal (não luminal) do lado do neuroepitélio ao longo do tempo é quantificado e é uma medida da permeabilidade neuroepitelial (Figura 1). Observamos que corantes 70 kDa e menores vão percorrer a neuroepitélio e pode ser detected fora do cérebro embrionário do peixe-zebra a 24 hpf (Figura 2). Este ensaio de retenção de corante pode ser usada para analisar a permeabilidade neuroepitelial em uma variedade de diferentes origens genéticas, em momentos diferentes durante o desenvolvimento, e após perturbações ambientais. Também pode ser útil para examinar a acumulação patológica de CSF. No geral, esta técnica permite aos pesquisadores analisar o papel e regulação da permeabilidade durante o desenvolvimento e doença.

Watch this Scientific Journal Video about An Assay for Permeability of the Zebrafish Embryonic Neuroepithelium at JoVE.com

An Assay for Permeability of the Zebrafish Embryonic Neuroepithelium

Nós descrevemos uma medição animal vivo todo quantitativa para a permeabilidade do cérebro de zebrafish embrionário. A técnica de análise da capacidade de retenção de fluido cerebrospinal e moléculas de diferentes pesos moleculares no interior do lúmen do tubo neural e quantifica o seu movimento para fora dos ventrículos. Este método é útil para a determinação de diferenças de permeabilidade epitelial e maturação durante o desenvolvimento e na doença.

Um ensaio para a permeabilidade do neuroepitélio Zebrafish Embryonic

The brain ventricular system is conserved among vertebrates and is composed of a series of interconnected cavities called brain ventricles, which form ...

an-assay-for-permeability-of-the-zebrafish-embryonic-neuroepithelium

Nanyang Technological University

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Neuroscience

9.4K visualizações.  Massachusetts Institute of Technology. Nós descrevemos uma medição animal vivo todo quantitativa para a permeabilidade do cérebro de zebrafish embrionário. A técnica de análise da capacidade de retenção de fluido cerebrospinal e moléculas de diferentes pesos moleculares no interior do lúmen do tubo neural e quantifica o seu movimento para fora dos ventrículos. Este método é útil para a determinação de diferenças de permeabilidade epitelial e maturação durante o desenvolvimento e na doença....

Vídeo: An Assay for Permeability of the Zebrafish Embryonic Neuroepithelium

Establishing Embryonic Mouse Neural Stem Cell Culture Using the Neurosphere Assay

In mammalians, stem cells acts as a source of undifferentiated cells to maintain cell genesis and renewal in different tissues and organs during the life span of the animal. They can potentially replace cells that are lost in the aging process or in the process of injury and disease. The existence of neural stem cells (NSCs) was first described by Reynolds and Weiss (1992) in the adult mammalian central nervous system (CNS) using a novel serum&#8208;free culture system, the neurosphere assay (NSA). Using this assay, it is also feasible to isolate and expand NSCs from different regions of the embryonic CNS. These in vitro expanded NSCs are multipotent and can give rise to the three major cell types of the CNS. While the NSA seems relatively simple to perform, attention to the procedures demonstrated here is required in order to achieve reliable and consistent results. This video practically demonstrates NSA to generate and expand NSCs from embryonic day 14-mouse brain tissue and provides technical details so one can achieve reproducible neurosphere cultures. The procedure includes harvesting E14 mouse embryos, brain microdissection to harvest the ganglionic eminences, dissociation of the harvested tissue in NSC medium to gain a single cell suspension, and finally plating cells in NSA culture. After 5-7 days in culture, the resulting primary neurospheres are passaged to further expand the number of the NSCs for future experiments.

This video protocol demonstrates the application of the neurosphere assay for the isolation and expansion of neural stem cells from the ganglionic eminences of embryonic day 14-mouse brain.

Estabelecer embrionárias de rato Cultura de Células-tronco neurais utilizando o ensaio Neurosphere

In mammalians, stem cells acts as a source of undifferentiated cells to maintain cell genesis and renewal in different tissues and organs during the life ...

Neurociência

The Neuroblast Assay: An Assay for the Generation and Enrichment of Neuronal Progenitor Cells from Differentiating Neural Stem Cell Progeny Using Flow Cytometry

Neural stem cells (NSCs) can be isolated and expanded in large-scale, using the neurosphere assay and differentiated into the three major cell types of the central nervous system (CNS); namely, astrocytes, oligodendrocytes and neurons. These characteristics make neural stem and progenitor cells an invaluable renewable source of cells for in vitro studies such as drug screening, neurotoxicology and electrophysiology and also for cell replacement therapy in many neurological diseases. In practice, however, heterogeneity of NSC progeny, low production of neurons and oligodendrocytes, and predominance of astrocytes following differentiation limit their clinical applications. Here, we describe a novel methodology for the generation and subsequent purification of immature neurons from murine NSC progeny using fluorescence activated cell sorting (FACS) technology. Using this methodology, a highly enriched neuronal progenitor cell population can be achieved without any noticeable astrocyte and bona fide NSC contamination. The procedure includes differentiation of NSC progeny isolated and expanded from E14 mouse ganglionic eminences using the neurosphere assay, followed by isolation and enrichment of immature neuronal cells based on their physical (size and internal complexity) and fluorescent properties using flow cytometry technology. Overall, it takes 5-7 days to generate neurospheres and 6-8 days to differentiate NSC progeny and isolate highly purified immature neuronal cells.

This video protocol demonstrates a novel method for the generation and subsequent purification of neuronal progenitor cells from a renewable source of neural stem cells (NSCs) based on their physical (size and internal granularity) and fluorescent properties using flow cytometry technology.

O Ensaio neuroblasto: um ensaio para a Geração e Enriquecimento de células progenitoras neuronais de Diferenciando Progeny Neural Stem Cell utilizando citometria de fluxo

Neural stem cells (NSCs) can be isolated and expanded in large-scale, using the neurosphere assay and differentiated into the three major cell types of ...

High-resolution Live Imaging of Cell Behavior in the Developing Neuroepithelium

The embryonic spinal cord consists of cycling neural progenitor cells that give rise to a large percentage of the neuronal and glial cells of the central nervous system (CNS). Although much is known about the molecular mechanisms that pattern the spinal cord and elicit neuronal differentiation1, 2, we lack a deep understanding of these early events at the level of cell behavior. It is thus critical to study the behavior of neural progenitors in real time as they undergo neurogenesis.
In the past, real-time imaging of early embryonic tissue has been limited by cell/tissue viability in culture as well as the phototoxic effects of fluorescent imaging. Here we present a novel assay for imaging such tissue for long periods of time, utilizing a novel ex vivo slice culture protocol and wide-field fluorescence microscopy (Fig. 1). This approach achieves long-term time-lapse monitoring of chick embryonic spinal cord progenitor cells with high spatial and temporal resolution.
This assay may be modified to image a range of embryonic tissues3, 4 In addition to the observation of cellular and sub-cellular behaviors, the development of novel and highly sensitive reporters for gene activity (for example, Notch signaling5) makes this assay a powerful tool with which to understand how signaling regulates cell behavior during embryonic development.

Imaging embryonic tissue in real-time is challenging over long periods of time. Here we present an assay for monitoring cellular and sub-cellular changes in chick spinal cord for long periods with high spatial and temporal resolution. This technique can be adapted for other regions of the nervous system and developing embryo.

De alta resolução de imagem ao vivo de comportamento de células no desenvolvimento neuroepitélio

The embryonic spinal cord consists of cycling neural progenitor cells that give rise to a large percentage of the neuronal and glial cells of the central ...

Manual Drainage of the Zebrafish Embryonic Brain Ventricles

Cerebrospinal fluid (CSF) is a protein rich fluid contained within the brain ventricles. It is present during early vertebrate embryonic development and persists throughout life. Adult CSF is thought to cushion the brain, remove waste, and carry secreted molecules1,2. In the adult and older embryo, the majority of CSF is made by the choroid plexus, a series of highly vascularized secretory regions located adjacent to the brain ventricles3-5. In zebrafish, the choroid plexus is fully formed at 144 hours post fertilization (hpf)6. Prior to this, in both zebrafish and other vertebrate embryos including mouse, a significant amount of embryonic CSF (eCSF) is present . These data and studies in chick suggest that the neuroepithelium is secretory early in development and may be the major source of eCSF prior to choroid plexus development7.
eCSF contains about three times more protein than adult CSF, suggesting that it may have an important role during development8,9. Studies in chick and mouse demonstrate that secreted factors in the eCSF, fluid pressure, or a combination of these, are important for neurogenesis, gene expression, cell proliferation, and cell survival in the neuroepithelium10-20. Proteomic analyses of human, rat, mouse, and chick eCSF have identified many proteins that may be necessary for CSF function. These include extracellular matrix components, apolipoproteins, osmotic pressure regulating proteins, and proteins involved in cell death and proliferation21-24. However, the complex functions of the eCSF are largely unknown.
We have developed a method for removing eCSF from zebrafish brain ventricles, thus allowing for identification of eCSF components and for analysis of the eCSF requirement during development. Although more eCSF can be collected from other vertebrate systems with larger embryos, eCSF can be collected from the earliest stages of zebrafish development, and under genetic or environmental conditions that lead to abnormal brain ventricle volume or morphology. Removal and collection of eCSF allows for mass spectrometric analysis, investigation of eCSF function, and reintroduction of select factors into the ventricles to assay their function. Thus the accessibility of the early zebrafish embryo allows for detailed analysis of eCSF function during development.

We present a method to collect cerebrospinal fluid (CSF) and to create a system which lacks CSF within the embryonic zebrafish brain ventricular system. This allows for further examination of CSF composition and its requirement during embryonic brain development.

Drenagem Manual dos Zebrafish ventrículos cerebrais embrionárias

Cerebrospinal fluid  (CSF) is a protein rich fluid contained within the brain ventricles. It is  present during early vertebrate embryonic development and ...

Ex vivo Live Imaging of Single Cell Divisions in Mouse Neuroepithelium

We developed a system that integrates live imaging of fluorescent markers and culturing slices of embryonic mouse neuroepithelium. We took advantage of existing mouse lines for genetic cell lineage tracing: a tamoxifen-inducible Cre line and a Cre reporter line expressing dsRed upon Cre-mediated recombination. By using a relatively low level of tamoxifen, we were able to induce recombination in a small number of cells, permitting us to follow individual cell divisions. Additionally, we observed the transcriptional response to Sonic Hedgehog (Shh) signaling using an Olig2-eGFP transgenic line 1-3 and we monitored formation of cilia by infecting the cultured slice with virus expressing the cilia marker, Sstr3-GFP 4. In order to image the neuroepithelium, we harvested embryos at E8.5, isolated the neural tube, mounted the neural slice in proper culturing conditions into the imaging chamber and performed time-lapse confocal imaging. Our ex vivo live imaging method enables us to trace single cell divisions to assess the relative timing of primary cilia formation and Shh response in a physiologically relevant manner. This method can be easily adapted using distinct fluorescent markers and provides the field the tools with which to monitor cell behavior in situ and in real time.

Ex vivo Live Imaging of Single Cell Divisions in Mouse Neuroepithelium

Here we develop the tools necessary for ex vivo live imaging to trace single cell divisions in the mouse E8.5 neuroepithelium

Ex vivo imagens ao vivo de divisões celulares simples no mouse neuroepithelium

We developed a system that integrates live imaging of fluorescent markers and culturing slices of embryonic mouse neuroepithelium. We took advantage of ...

Patch Clamp Recordings from Embryonic Zebrafish Mauthner Cells

Mauthner cells (M-cells) are large reticulospinal neurons located in the hindbrain of teleost fish. They are key neurons involved in a characteristic behavior known as the C-start or escape response that occurs when the organism perceives a threat. The M-cell has been extensively studied in adult goldfish where it has been shown to receive a wide range of excitatory, inhibitory and neuromodulatory signals1. We have been examining M-cell activity in embryonic zebrafish in order to study aspects of synaptic development in a vertebrate preparation. In the late 1990s Ali and colleagues developed a preparation for patch clamp recording from M-cells in zebrafish embryos, in which the CNS was largely intact2,3,4. The objective at that time was to record synaptic activity from hindbrain neurons, spinal cord neurons and trunk skeletal muscle while maintaining functional synaptic connections within an intact brain-spinal cord preparation. This preparation is still used in our laboratory today. To examine the mechanisms underlying developmental synaptic plasticity, we record excitatory (AMPA and NMDA-mediated)5,6 and inhibitory (GABA and glycine) synaptic currents from developing M-cells. Importantly, this unique preparation allows us to return to the same cell (M-cell) from preparation to preparation to carefully examine synaptic plasticity and neuro-development in an embryonic organism. The benefits provided by this preparation include 1) intact, functional synaptic connections onto the M-cell, 2) relatively inexpensive preparations, 3) a large supply of readily available embryos 4) the ability to return to the same cell type (i.e. M-cell) in every preparation, so that synaptic development at the level of an individual cell can be examined from fish to fish, and 5) imaging of whole preparations due to the transparent nature of the embryos.

We have developed an intact brain-spinal cord preparation to record and monitor electrical activity via patch clamp recording from the Mauthner neurons and other reticulospinal cells in zebrafish embryos. Thus, we are able to record excitatory and inhibitory synaptic currents, voltage-gated channel activity and action potentials from key neurons in a developing embryo.

Grampo patch Gravações de Embryonic Cells Zebrafish Mauthner

Mauthner cells (M-cells) are large  reticulospinal neurons located in the hindbrain of teleost fish. They are key  neurons involved in a characteristic ...

Live Imaging of Mitosis in the Developing Mouse Embryonic Cortex

Although of short duration, mitosis is a complex and dynamic multi-step process fundamental for development of organs including the brain. In the developing cerebral cortex, abnormal mitosis of neural progenitors can cause defects in brain size and function. Hence, there is a critical need for tools to understand the mechanisms of neural progenitor mitosis. Cortical development in rodents is an outstanding model for studying this process. Neural progenitor mitosis is commonly examined in fixed brain sections. This protocol will describe in detail an approach for live imaging of mitosis in ex vivo embryonic brain slices. We will describe the critical steps for this procedure, which include: brain extraction, brain embedding, vibratome sectioning of brain slices, staining and culturing of slices, and time-lapse imaging. We will then demonstrate and describe in detail how to perform post-acquisition analysis of mitosis. We include representative results from this assay using the vital dye Syto11, transgenic mice (histone H2B-EGFP and centrin-EGFP), and in utero electroporation (mCherry-&#945;-tubulin). We will discuss how this procedure can be best optimized and how it can be modified for study of genetic regulation of mitosis. Live imaging of mitosis in brain slices is a flexible approach to assess the impact of age, anatomy, and genetic perturbation in a controlled environment, and to generate a large amount of data with high temporal and spatial resolution. Hence this protocol will complement existing tools for analysis of neural progenitor mitosis.

Neural progenitor mitosis is a critical parameter of neurogenesis. Much of our understanding of neural progenitor mitosis is based on analysis of fixed tissue. Live imaging in embryonic brain slices is a versatile technique to assess mitosis with high temporal and spatial resolution in a controlled environment.

Imagens ao vivo da mitose no desenvolvimento Cortex embrionárias de camundongos

Although of short duration, mitosis is a complex and dynamic multi-step process fundamental for development of organs including the brain. In the ...

An Assay for Measuring the Effects of Ethanol on the Locomotion Speed of Caenorhabditis elegans

Alcohol use disorders are a significant public health concern, for which there are few effective treatment strategies. One difficulty that has delayed the development of more effective treatments is the relative lack of understanding of the molecular underpinnings of the effects of ethanol on behavior. The nematode, Caenorhabditis elegans (C.&#160;elegans), provides a useful model in which to generate and test hypotheses about the molecular effects of ethanol. Here, we describe an assay that has been developed and used to examine the roles of particular genes and environmental factors in behavioral responses to ethanol, in which locomotion is the behavioral output. Ethanol dose-dependently causes an acute depression of crawling on an agar surface. The effects are dynamic; animals exposed to a high concentration demonstrate an initial strong depression of crawling, referred to here as initial sensitivity, and then partially recover locomotion speed despite the continued presence of the drug. This ethanol-induced behavioral plasticity is referred to here as the development of acute functional tolerance. This assay has been used to demonstrate that these two phenotypes are distinct and genetically separable. The straightforward locomotion assay described here is suitable for examining the effects of both genetic and environmental manipulations on these acute behavioral responses to ethanol in C.&#160;elegans.

An Assay for Measuring the Effects of Ethanol on the Locomotion Speed of Caenorhabditis elegans

C. elegans is a useful model for studying the effects of ethanol on behavior. We present a behavioral assay that quantifies the effects of ethanol on the locomotion speed of crawling worms; both initial sensitivity and the development of acute functional tolerance to ethanol can be measured with this assay.

Um ensaio para medir os efeitos do etanol sobre a velocidade de Locomotion<em&gt; Caenorhabditis elegans</em

Alcohol use disorders are a significant public health concern, for which there are few effective treatment strategies. One difficulty that has delayed the ...

Electrophysiological Method for Recording Intracellular Voltage Responses of Drosophila Photoreceptors and Interneurons to Light Stimuli In Vivo

Voltage responses of insect photoreceptors and visual interneurons can be accurately recorded with conventional sharp microelectrodes. The method described here enables the investigator to measure long-lasting (from minutes to hours) high-quality intracellular responses from single Drosophila R1-R6 photoreceptors and Large Monopolar Cells (LMCs) to light stimuli. Because the recording system has low noise, it can be used to study variability among individual cells in the fly eye, and how their outputs reflect the physical properties of the visual environment. We outline all key steps in performing this technique. The basic steps in constructing an appropriate electrophysiology set-up for recording, such as design and selection of the experimental equipment are described. We also explain how to prepare for recording by making appropriate (sharp) recording and (blunt) reference electrodes. Details are given on how to fix an intact fly in a bespoke fly-holder, prepare a small window in its eye and insert a recording electrode through this hole with minimal damage. We explain how to localize the center of a cell's receptive field, dark- or light-adapt the studied cell, and to record its voltage responses to dynamic light stimuli. Finally, we describe the criteria for stable normal recordings, show characteristic high-quality voltage responses of individual cells to different light stimuli, and briefly define how to quantify their signaling performance. Many aspects of the method are technically challenging and require practice and patience to master. But once learned and optimized for the investigator's experimental objectives, it grants outstanding in vivo neurophysiological data.

Electrophysiological Method for Recording Intracellular Voltage Responses of Drosophila Photoreceptors and Interneurons to Light Stimuli In Vivo

Sharp microelectrodes enable accurate electrophysiological characterization of photoreceptor and visual interneuron output in living Drosophila. Here we show how to use this method to record high-quality voltage responses of individual cells to controlled light stimulation. This method is ideal for studying neural information processing in insect compound eyes.

Método eletrofisiológico para respostas gravação intracelular de tensão<em&gt; Drosophila</em&gt; Fotorreceptores e Interneurônios à luz Estímulos<em&gt; In Vivo</em

Voltage responses of insect photoreceptors and visual interneurons can be accurately recorded with conventional sharp microelectrodes. The method ...

Assay Development for High Content Quantification of Sod1 Mutant Protein Aggregate Formation in Living Cells

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that can be caused by inherited mutations in the gene encoding copper-zinc superoxide dismutase 1 (SOD1). The structural instability of SOD1 and the detection of SOD1-positive inclusions in familial-ALS patients supports a potential causal role for misfolded and/or aggregated SOD1 in ALS pathology. In this study, we describe the development of a cell-based assay designed to quantify the dynamics of SOD1 aggregation in living cells by high content screening approaches. Using lentiviral vectors, we generated stable cell lines expressing wild-type and mutant A4V SOD1 tagged with yellow fluorescent protein and found that both proteins were expressed in the cytosol without any sign of aggregation. Interestingly, only SOD1 A4V stably expressed in HEK-293, but not in U2OS or SH-SY5Y cell lines, formed aggregates upon proteasome inhibitor treatment. We show that it is possible to quantify aggregation based on dose-response analysis of various proteasome inhibitors, and to track aggregate-formation kinetics by time-lapse microscopy. Our approach introduces the possibility of quantifying the effect of ALS mutations on the role of SOD1 in aggregate formation as well as screening for small molecules that prevent SOD1 A4V aggregation.

We describe a method to quantify the aggregation of misfolded proteins. Our protocol details lentiviral induced stable cell line generation, automated confocal imaging, and image analysis of protein aggregates. As an illustrative application, we studied the effect of small molecules in promoting SOD1 aggregation in a time- and dose-dependent manner.

Desenvolvimento de ensaio para quantificação de conteúdo elevado de Sod1 proteína mutante formação agregada em células vivas

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that can be caused by inherited mutations in the gene encoding copper-zinc ...