We would like to acknowledge David O'Brien for his support with data analysis, and all the members of the Canto-Soler lab for their critical discussions. This work was supported by NIH grants EY004859 and EY022631 (MVCS), Core Grant EY1765, and an unrestricted departmental grant from Research to Prevent Blindness, Inc.

Todos os procedimentos descritos neste trabalho foram realizadas de acordo com as orientações recomendadas pelo Animal Care e do Comitê Use da Universidade Johns Hopkins. 1. Ahead of Time: preparação de instrumentos, reagentes e pratos <ol><li> Preparação de Ovos: ovos de galinha fertilizados Incubar Leghorn branco a 37,5 ° C e 60% de humidade relativa durante 5 dias numa incubadora de ovos. NOTA: Uma incubadora com capacidade de balanço pode ser útil para padronizar e sincronizar o desenvolvimento embrionário, mas de balanço não é estritamente necessário para o resultado do presente protocolo. </li><li> O plasmídeo Preparação: <ol><li> Design O plasmídeo para construir a sobre-expressão ou infra-regulação de genes (por exemplo, através da utilização de tecnologia RNAi 1,34), conforme necessário. Incluir um gene repórter (por exemplo, EGFP, RFP ou LacZ) na construção, sempre que possível. Nota: Alguns promotores vulgarmente utilizados tais como CMV, pode tornar-se silenciado após o tempo. O promot CAGer (beta-actina de galinha com promotor de CMV) é uma boa alternativa, proporcionando a expressão eficiente a longo prazo do gene de interesse 35-37. </li><li> Prepara-se uma solução de plasmídeo a uma concentração de 1,5 mg / mL em PBS estéril. OPCIONAL: Preparar a solução de plasmídeo antes do tempo e armazená-lo congelado até que esteja pronto para uso. NOTA: Superior concentrações plasmídeo não resultar num aumento significativo da eficiência, enquanto que utilizando concentrações mais baixas de plasmídeo diminuir a eficiência de transfecção 1. </li></ol></li><li> Eletrodos: <ol><li> Para o uso ânodo uma grossa de ouro com ponta do eletrodo (ver Tabela de Específico materiais / equipamentos). Limpe com etanol 70%. NOTA: Isolamento do eléctrodo de ouro derrubado, deixando cerca de 0,5 mm expostos, é aconselhável minimizar o vazamento da corrente eléctrica. Informações para material isolante podem ser encontrados na tabela de materiais específicos. </li><li> Faça um cátodo de um 2,5 milímetros quadrados bfilamento boi, 4,5 mm de largura (normalmente usado em puxadores micropipeta). Com o auxílio de uma pinça, desfazer a caixa quadrada e endireitar filamento em uma longa faixa. Em seguida, sob microscópio de dissecção e utilizando uma régua como guia, dobrar o filamento em um quadrado &#39;U&#39; 3 mm de comprimento na base e 2 mm de altura num lado, com o outro lado do restante comprimento do filamento (Figura 1 , C - D). Utilizando uma pinça, mergulhe o arame em etanol a 96% e chama para esterilizar. Em seguida, anexar um condutor eléctrico com um pequeno jacaré para o braço mais comprido do eletrodo. </li></ol></li><li> Setup Eletroporação Câmara: <ol><li> Preparar a câmara de electroporação por corte da tampa de um tubo de microcentrífuga de 1,5 ml estéril e aposição, o lado plano para baixo, para uma placa de Petri de 100 mm utilizando uma fita (Figura 1E). NOTA: Outro recipiente sob a forma de um poço de tamanho semelhante funciona; No entanto, um tubo de microcentrífuga de tampa é facilmente acessível e autoclavável. O bemdeve ser o suficiente para abrigar um eletrodo pintinho olho e cátodo grande, mas não tão grande quanto a resultar em uma perda de solução de plasmídeo. </li></ol></li></ol> 2. Ex ovo Eletroporação Procedimento <ol><li> Preparação de instrumentos: <ol><li> Esterilizar ferramentas micro-dissecção (2 pares de grandes pinças Moloney curvas para abrir cascas de ovos e escavar para fora embriões, 2 pares de fine-ponta curvada pinças Dumont para a remoção de RPE, um par de Bonn dentada pinças para remoção da lente e vítreo) por imersão do dicas em etanol a 96% e flamejante. Escopo de dissecação limpa usando lenços mergulhados em etanol a 70%. Aquecer uma garrafa de Solução Salina Equilibrada de cálcio e de magnésio estéril livre de Hank (HBSS-CMF) em um banho de água a 37 ° C. Preencha 100 mm placas de Petri estéreis para 3/4 com warm-CMF HBSS. </li><li> Coloque câmara de eletroporação sob outro microscópio de dissecação limpa e encha com 120 ml de solução de plasmídeo. Conectar eléctrodos para electroporação aparelho, tornandoCertifique-se eletrodo feito sob medida está ligado ao pólo negativo e eletrodo de ouro derrubado ao pólo positivo. </li></ol></li><li> Colheita de embriões: <ol><li> Limpe os ovos, limpando conchas com toalhetes humedecidos em etanol a 70%. Manter procedimento estéril em todo o resto do protocolo para evitar contaminação levando para as culturas. Usando grandes pinças Moloney curvas abrir cuidadosamente um buraco na casca do ovo batendo suavemente na ponta arredondada de um ovo (através da câmara de ar) e, em seguida, agarrando e puxando pedaços de casca. </li><li> Com outro par de fórceps remover membranas e coletar embriões escavando-lo para fora do ovo (tomando cuidado para não danificar o embrião). Coloque-o em um prato com CMF-HBSS. NOTA: como coletar muitos embriões conforme necessário para obter o número desejado de copos da retina para eletroporação, conforme especificado no 2.4.4 </li><li> Passo crítico: Estágio os embriões de acordo com Hamburger e Hamilton 38. NOTA: Para obter máxima eficiência embriõesdeve estar na fase 27 (Figura 2A). </li><li> Euthanize os embriões por decapitação usando uma pinça Moloney. </li></ol></li><li> Obtenção de Copas da retina: <ol><li> Com uma pinça Dumont finas, enuclear cuidadosamente os olhos e transferir para um novo CMF-HBSS prato. </li><li> A partir da parte posterior de cada olho, perto da cabeça do nervo óptico, e usando duas pinças Dumont finas, introduzir uma ponta de cada par de pinças entre a retina neural e RPE e dissecar cuidadosamente para fora do RPE sendo cauteloso para não danificar o neural retina (Figura 2B). NOTA: A falta de Ca 2+ e Mg 2+ na solução vai ajudar a separar EPR da retina neural mais facilmente. </li></ol></li><li> Eletroporação: <ol><li> Configurar os parâmetros de electroporador para entregar 5 pulsos quadrados de 15 Volts, 50 ms, duração e intervalo de 950 ms. Place &#39;U&#39; em forma eletrodo negativo interior da câmara de eletroporação (microcentrifuge tampa de enchimentoed com 120 ul de solução contendo plasmídeo-). </li><li> Usando uma pinça Dumont curvas transferir uma xícara de retina para a câmara de eletroporação (por escavar, não prensagem), e colocá-lo dentro do eletrodo em forma de &quot;U&quot;, com a parte posterior da retina para a parte inferior do eléctrodo e a lente virada para cima ( Figura 2D). </li><li> Coloque o ânodo de modo que toque a parte anterior do olho, próximo da lente, e usando o pedal do electroporador entregar os impulsos eléctricos. </li><li> Transferir electroporadas copo da retina para uma nova placa de Petri com CMF-HBSS e repete procedimento de electroporação com cada um dos restantes copos da retina. NOTA: Até 6 copos da retina pode ser electroporada com a mesma solução de plasmídeo sem uma diminuição significativa da eficiência da transfecção. </li><li> Retire a lente e corpo vítreo de cada copo de retina electroporated agarrando-os com uma pinça de Bona dentadas e puxando suavemente através de tele pupila abertura, mantendo o olho no lugar com a volta das pinças Dumont curvas. </li><li> Proceder à dissociação e cultura das células da retina electroporated seguintes procedimentos padrão. NOTA: Para obter um protocolo detalhado sobre a dissociação e cultura de células da retina pintinho referem-se a Vergara e Canto-Soler, 2012, arquivo adicionais 4 21 Neste protocolo, as células são semeadas a baixa densidade em placas de 6 poços revestidos por poliornitina ou 35. pratos -mm (6 x 10 5 células / 35 mm de diâmetro bem ou prato). O meio utilizado é o meio 199 com penicilina / glutamina, 10% de soro fetal de vitelo (FCS), e ácido linoleico-BSA a 100 ng / ml. As culturas são mantidas numa atmosfera humidificada a 37 ° C incubadora com 5% de CO 2. Utilizando este procedimento, a 5 - 6 6 x 10 células podem ser obtidas tipicamente por cada fase 27 do olho electroporadas. NOTA: O ideal é não mais do que 3 horas devem passar entre colheita e chapeamento de celular, para garantir uma boa sobrevivência celulare minimizar o estresse. Um tempo típico para observação e análise posterior é após 4 dias em cultura, uma vez que neste momento as células têm alcançado boa diferenciação morfológica e molecular e sobrevivência ainda é alta. </li></ol></li></ol>

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M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+hybrid+promoter-containing+vector+for+direct+cloning+and+enhanced+expression+of+PCR-amplified+ORFs+in+mammalian+cells.">A hybrid promoter-containing vector for direct cloning and enhanced expression of PCR-amplified ORFs in mammalian cells.</a> Mol Biol Rep. 37 (6), 2757-2765 (2009).</li><li>Hamburger, V., Hamilton, H. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+series+of+normal+stages+in+the+development+of+the+chick+embryo.">A series of normal stages in the development of the chick embryo.</a> Dev Dyn. 195 (4), 231-272 (1992).</li></ol>

The authors declare that they have no competing financial interests or other conflicts of interest.

O passo mais crítico para o sucesso deste protocolo é a selecção do estágio apropriado dos embriões. Em publicações anteriores, uma série de estágios embrionários é dada para estas culturas, tipicamente, definida pelos dias de incubação ou embrionárias dias (ED); portanto, é geralmente assumido que a utilização de ED de 5 a 6 ED embriões irá produzir resultados equivalentes. No entanto verificou-se que na fase 27 (ED 5), a eficiência de transfecção será de cerca de 22% da população total de cé...

Culturas de células dissociadas de retinas de pintainho embrionário têm sido amplamente utilizados para o estudo de vários aspectos da biologia celular de fotorreceptores, incluindo a sua sobrevivência 2-9, 10-12 diferenciação, crescimento de neuritos 13, e mais. As vantagens deste sistema, desenvolvido na década de 1980 por Ruben Adler e colaboradores e aperfeiçoados por suas e de outros grupos 14-20, residem nas características intrínsecas do pinto como um modelo animal 21. O grande tamanho do olho do pintainho, mesmo em estádios embrionários, fornece grandes quantidades de material para culturas. Além disso, quando as culturas são realizadas utilizando dia embrionário (ED) 5 - 6 retinas, 55 - 80% das suas células progenitoras diferenciam como fotorreceptores 14,15,18,22,23, e desde cerca de 86% dos fotorreceptores nesse animal são 24 cones, estas culturas são particularmente adequados para estudos que focalizam o tipo de célula. Temos recentemente desenPED e caracterizada uma técnica simples que permite um processo de alta eficiência de transfecção de plasmídeo das células nestas culturas, alargando assim a utilidade deste sistema, facilitando estudos missexpression genética 1. O desenvolvimento desta técnica resultou de um vazio na literatura científica de métodos que proporcionem um nível aceitável de transfecção para permitir o estudo da função dos genes de uma maneira autónoma da célula. Isto é em parte porque as culturas primárias neuronais são notoriamente difíceis de transfectar 25,26. Algumas das técnicas mais comumente usadas anteriormente disponíveis para o efeito métodos de transfecção incluiu químicos, tais como lipofecção ou cálcio transfecção mediada por fosfato, que resultam em eficácia na ordem de 3-5% e pode exercer toxicidade considerável 27-32. Embora a utilização de plasmídeos com um sistema de repórter enzimático pode contornar o problema da falta de eficiência de transfecção por amplificação do sinal, eles não fazemdiscriminar efeitos específicos de células, e os seus resultados são baseados em uma população de células pequenas que podem não ser representativas do conjunto. Outro método amplamente utilizado na pintinho, infecção por vírus RCAS, só é aplicável a células em proliferação e, portanto, não é adequado para este sistema de cultura de retina primário 33. No protocolo de corrente pintainho embrionário olhos são enucleados na fase 27 (ED 5), o epitélio pigmentado da retina (RPE) é removido, e o copo da retina é colocado numa câmara de electroporação preenchido com uma solução contendo o plasmídeo e electroporadas utilizando feito por encomenda eléctrodos, seguido pela dissociação da retina e de cultura usando técnicas convencionais. 21 Depois de optimizar este procedimento, temos sido capazes de conseguir de forma consistente eficiências de transfecção na ordem de 22% do número total de células em cultura e de 25% na população de fotorreceptores por si só, sem comprometer as características de sobrevivência e diferenciação de aculturas 1. Aqui nós fornecemos um protocolo detalhado descrevendo todas as etapas importantes deste processo, a fim de garantir o sucesso e reprodutibilidade desta técnica.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>ECM 830 Electro Square Porator</td>
			<td>BTX/ Harvard Apparatus</td>
			<td>45-0052</td>
			<td></td>
		</tr>
		<tr>
			<td>Genetrode, L-Shaped, 5 mm Gold Tip</td>
			<td>BTX/ Harvard Apparatus</td>
			<td>45-0115 model 512</td>
			<td>Gold tipped electrode used as anode</td>
		</tr>
		<tr>
			<td>Polyimide Tubing</td>
			<td>Vention Medical</td>
			<td>custom made</td>
			<td>Internal Diameter: 0.5mm / wall thickness: 0.15-0.2mm. Used for insulating gold tiped electrode</td>
		</tr>
		<tr>
			<td>2.5mm square box filament, 4.5mm wide</td>
			<td>Sutter Instrument Company</td>
			<td>FB245B</td>
			<td>Used to make cathode electrode</td>
		</tr>
		<tr>
			<td>HBSS, no calcium, no magnesium, no phenol red</td>
			<td>Gibco - Life Technologies</td>
			<td>14175-095</td>
			<td></td>
		</tr>
		<tr>
			<td>Moloney forceps</td>
			<td>Roboz</td>
			<td>RS-8254</td>
			<td>Serrated; Slight Curve; 4.5&#34; Length</td>
		</tr>
		<tr>
			<td>Dumont tweezers 5/45</td>
			<td>Roboz</td>
			<td>RS-5058</td>
			<td>Pattern #5, 45 Degree Angle; .10 X .06mm Tip Size; 109mm Length</td>
		</tr>
		<tr>
			<td>Bonn micro forceps, 1x2 teeth</td>
			<td>Roboz</td>
			<td>RS-5172</td>
			<td>Tying Platform; 1X2 Teeth, 0.12mm Teeth; 3.75&#34; Length; .3mm Tip Width</td>
		</tr>
	</tbody>
</table>

efficient gene transfer in chick retinas for primary cell culture studies: an ex-ovo electroporation approach

As culturas enriquecidas com cone fotorreceptoras da retina derivadas de bico embrionárias tornaram-se uma ferramenta indispensável para pesquisadores de todo o mundo que estudam a biologia dos neurônios da retina, particularmente fotorreceptores. As aplicações deste sistema excede investigação fundamental, uma vez que podem ser facilmente adaptados às tecnologias de elevado rendimento para o desenvolvimento de drogas. No entanto, a manipulação genética de fotorreceptores da retina nestas culturas tem provado ser muito desafiador, que levanta uma importante limitação para a utilidade do sistema. Temos recentemente desenvolvido e validado um ex ovo técnica de electroporação plasmídeo que aumenta a taxa de transfecção de células de retina nestas culturas por cinco vezes em comparação com outros protocolos actualmente disponíveis 1. Neste método pinto embrionário olhos são enucleados no estágio 27, o RPE é removido, ea taça da retina é colocado em uma solução contendo plasmídeo e electroporado usando custom- facilmente construídosfeitos eléctrodos. As retinas são então dissociados e cultivadas utilizando procedimentos padrão. Esta técnica pode ser aplicada a estudos sobre-expressão, bem como para a regulação negativa da expressão do gene, por exemplo, através da utilização de tecnologia RNAi-driven plasmídeo, geralmente atingir a expressão do transgene em 25% da população de fotorreceptores. O formato de vídeo da presente publicação irá tornar esta tecnologia de fácil acesso para os pesquisadores da área, permitindo o estudo da função dos genes em culturas de retina primários. Incluímos também explicações detalhadas sobre as etapas críticas de este procedimento para um resultado de sucesso e reprodutibilidade.

Aqui apresentamos um protocolo simples para o plasmídeo transfecção em copos de bico da retina enucleados para posterior cultura de células dissociadas. Transfecção é obtida por eletroporação usando fácil de fazer eletrodos personalizados (Figuras 1 - 2). Os parâmetros descritos neste protocolo foram otimizados para obter eficiências de transfecção que variam entre 20 e 27% (com uma média de 22%) (Figura 3D). Note-se que, pelas razões acima expostas, est...

Watch this Scientific Journal Video about Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach at JoVE.com

Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach

Culturas de células da retina pintinho embrionárias constituem ferramentas importantes para o estudo da biologia de fotorreceptores. Nós desenvolvemos uma técnica de transferência de gene eficiente com base em ex ovo plasmídeo electroporação das retinas antes da cultura. Esta técnica aumenta consideravelmente a eficiência de transfecção através de protocolos disponíveis atualmente, fazendo a manipulação genética viável para este sistema.

Transferência de Gene eficiente em retinas pintainho para célula primária Estudos de Cultura: An<em&gt; Ex-ovo</em&gt; Eletroporação Approach

The cone photoreceptor-enriched cultures derived from embryonic chick retinas have become an indispensable tool for researchers around the world studying ...

efficient-gene-transfer-chick-retinas-for-primary-cell-culture

Research

JoVE Journal

Developmental Biology

Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach

8.1K visualizações.  The Johns Hopkins University School of Medicine.  Culturas de células da retina pintinho embrionárias constituem ferramentas importantes para o estudo da biologia de fotorreceptores. Nós desenvolvemos uma técnica de transferência de gene eficiente com base em ex ovo plasmídeo electroporação das retinas antes da cultura. Esta técnica aumenta consideravelmente a eficiência de transfecção através de protocolos disponíveis atualmente, fazendo a manipulação genética viável para este sistema. 

Vídeo: Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach

Optimized Ex-ovo Culturing of Chick Embryos to Advanced Stages of Development

Research in anatomy, embryology, and developmental biology has largely relied on the use of model organisms. In order to study development in live embryos model organisms, such as the chicken, are often used. The chicken is an excellent model organism due to its low cost and minimal maintenance, however they present observational challenges because they are enclosed in an opaque eggshell. In order to properly view the embryo as it develops, the shell must be windowed or removed. Both windowing and ex ovo techniques have been developed to assist researchers in the study of embryonic development. However, each of the methods has limitations and challenges. Here, we present a simple, optimized ex ovo culture technique for chicken embryos that enables the observation of embryonic development from stage HH 19 into late stages of development (HH 40), when many organs have developed. This technique is easy to adopt in both undergraduate classes and more advanced research laboratories where embryo manipulations are conducted.

Optimized Ex-ovo Culturing of Chick Embryos to Advanced Stages of Development

Viewing and accessing the chicken embryo during development can be challenging. We have developed an ex ovo method that is simple, cost effective, and can easily be used in a classroom or research setting. This method provides access to the embryo into late stages of embryonic development (HH 40).

Otimizado<em&gt; Ex-ovo</em&gt; A cultura de Chick embriões para estágio avançado de desenvolvimento

Research in anatomy, embryology, and developmental biology has largely relied on the use of model organisms. In order to study development in live embryos ...

Biologia do Desenvolvimento

Culture of Embryonic Mouse Cochlear Explants and Gene Transfer by Electroporation

Auditory hair cells located within the mouse organ of Corti detect and transmit sound information to the central nervous system. The mechanosensory hair cells are aligned in one row of inner hair cells and three rows of outer hair cells that extend along the basal to apical axis of the cochlea. The explant culture technique described here provides an efficient method to isolate and maintain cochlear explants from the embryonic mouse inner ear. Also, the morphology and molecular characteristics of sensory hair cells and nonsensory supporting cells within the cochlear explant cultures resemble those observed in vivo and can be studied within its intrinsic cellular environment. The cochlear explants can serve as important experimental tools for the identification and characterization of molecular and genetic pathways that are involved in cellular specification and patterning. Although transgenic mouse models provide an effective approach for gene expression studies, a considerable number of mouse mutants die during embryonic development thereby hindering the analysis and interpretation of developmental phenotypes. The organ of Corti from mutant mice that die before birth can be cultured so that their in vitro development and responses to different factors can be analyzed. Additionally, we describe a technique for electroporating embryonic cochlear explants ex vivo which can be used to downregulate or overexpress specific gene(s) and analyze their potential endogenous function and test whether specific gene product is necessary or sufficient in a given context to influence mammalian cochlear development1-8.

We present a method that describes isolation and culture of cochlear explants from embryonic mouse inner ear. We also demonstrate a method for gene transfer into cochlear explants via square-wave electroporation. The in vitro explant culture coupled with gene transfer technique enables researchers to study the effects of altering gene expression during development.

Cultura da embrionárias mouse cocleares explantes e Gene Transferência de Eletroporação

Auditory hair cells located within the mouse organ of Corti detect and transmit sound information to the central nervous system. The mechanosensory hair ...

An Optogenetic Approach for Assessing Formation of Neuronal Connections in a Co-culture System

Here we describe a protocol to generate a co-culture consisting of 2 different neuronal populations. Induced pluripotent stem cells (iPSCs) are reprogrammed from human fibroblasts using episomal vectors. Colonies of iPSCs can be observed 30 days after initiation of fibroblast reprogramming. Pluripotent colonies are manually picked and grown in neural induction medium to permit differentiation into neural progenitor cells (NPCs). iPSCs rapidly convert into neuroepithelial cells within 1 week and retain the capability to self-renew when maintained at a high culture density. Primary mouse NPCs are differentiated into astrocytes by exposure to a serum-containing medium for 7 days and form a monolayer upon which embryonic day 18 (E18) rat cortical neurons (transfected with channelrhodopsin-2 (ChR2)) are added. Human NPCs tagged with the fluorescent protein, tandem dimer Tomato (tdTomato), are then seeded onto the astrocyte/cortical neuron culture the following day and allowed to differentiate for 28 to 35 days. We demonstrate that this system forms synaptic connections between iPSC-derived neurons and cortical neurons, evident from an increase in the frequency of synaptic currents upon photostimulation of the cortical neurons. This co-culture system provides a novel platform for evaluating the ability of iPSC-derived neurons to create synaptic connections with other neuronal populations.

A protocol to generate a co-culture system consisting of neurons derived from induced pluripotent stem cells (iPSCs), primary cortical neurons and astrocytes is described. This co-culture system allows detection of the formation of synaptic contacts and circuits between new, iPSC-derived neurons and pre-existing cortical neurons expressing channelrhodopsin-2.

Uma Abordagem Optogenetic para Avaliar Formação das conexões neuronais em um sistema de co-cultura

Here we describe a protocol to generate a co-culture consisting of 2 different neuronal populations. Induced pluripotent stem cells (iPSCs) are ...

Forward Genetic Approach to Uncover Stress Resistance Genes in Mice &#8212; A High-throughput Screen in ES Cells

Phenotype-driven genetic screens in mice is a powerful technique to uncover gene functions, but are often hampered by extremely high costs, which severely limits its potential. We describe here the use of mouse embryonic stem (ES) cells as surrogate cells to screen for a phenotype of interest and subsequently introduce these cells into a host embryo to develop into a living mouse carrying the phenotype. This method provides (1) a cost effective, high-throughput platform for genetic screen in mammalian cells; (2) a rapid way to identify the mutated genes and verify causality; and (3) a short-cut to develop mouse mutants directly from these selected ES cells for whole animal studies. We demonstrated the use of paraquat (PQ) to select resistant mutants and identify mutations that confer oxidative stress resistance. Other stressors or cytotoxic compounds may also be used to screen for resistant mutants to uncover novel genetic determinants of a variety of cellular stress resistance.

Forward Genetic Approach to Uncover Stress Resistance Genes in Mice &amp;#8212; A High-throughput Screen in ES Cells

Stress resistance is one of the hallmarks for longevity and is known to be genetically governed. Here, we developed an unbiased high-throughput method to screen for mutations that confer stress resistance in ES cells with which to develop mouse models for longevity studies.

Abordagem genética para a frente para descobrir genes de resistência a estresse em ratos - Uma tela de alta capacidade em células ES

Phenotype-driven genetic screens in mice is a powerful technique to uncover gene functions, but are often hampered by extremely high costs, which severely ...

Ex Vivo Culture of Chick Cerebellar Slices and Spatially Targeted Electroporation of Granule Cell Precursors

The cerebellar external granule layer (EGL) is the site of the largest transit amplification in the developing brain, and an excellent model for studying neuronal proliferation and differentiation. In addition, evolutionary modifications of its proliferative capability have been responsible for the dramatic expansion of cerebellar size in the amniotes, making the cerebellum an excellent model for evo-devo studies of the vertebrate brain. The constituent cells of the EGL, cerebellar granule progenitors, also represent a significant cell of origin for medulloblastoma, the most prevalent paediatric neuronal tumour. Following transit amplification, granule precursors migrate radially into the internal granular layer of the cerebellum where they represent the largest neuronal population in the mature mammalian brain. In chick, the peak of EGL proliferation occurs towards the end of the second week of gestation. In order to target genetic modification to this layer at the peak of proliferation, we have developed a method for genetic manipulation through ex vivo electroporation of cerebellum slices from embryonic Day 14 chick embryos. This method recapitulates several important aspects of in vivo granule neuron development and will be useful in generating a thorough understanding of cerebellar granule cell proliferation and differentiation, and thus of cerebellum development, evolution and disease.

Ex Vivo Culture of Chick Cerebellar Slices and Spatially Targeted Electroporation of Granule Cell Precursors

The cerebellar external granule layer is the site of the largest transit amplification in the developing brain. Here, we present a protocol to target genetic modification to this layer at the peak of proliferation using ex vivo electroporation and culture of cerebellar slices from embryonic Day 14 chick embryos.

Ex Cultura Vivo de Pintainho Cerebelar Slices e voltadas para o espaço Eletroporação do grânulo precursores de células

The cerebellar external granule layer (EGL) is the site of the largest transit amplification in the developing brain, and an excellent model for studying ...

Gene Transfer into the Chicken Auditory Organ by In Ovo Micro-electroporation

Chicken embryos are ideal model systems for studying embryonic development as manipulations of gene function can be conducted with relative ease in ovo. The inner ear auditory sensory organ is critical for our ability to hear. It houses a highly specialized sensory epithelium that consists of mechano-transducing hair cells (HCs) and surrounding glial-like supporting cells (SCs). Despite structural differences in the auditory organs, molecular mechanisms regulating the development of the auditory organ are evolutionarily conserved between mammals and aves. In ovo electroporation is largely limited to early stages at E1 - E3. Due to the relative late development of the auditory organ at E5, manipulations of the auditory organ by in ovo electroporation past E3 are difficult due to the advanced development of the chicken embryo at later stages. The method presented here is a transient gene transfer method for targeting genes of interest at stage E4 - E4.5 in the developing chicken auditory sensory organ via in ovo micro-electroporation. This method is applicable for gain- and loss-of-functions with conventional plasmid DNA-based expression vectors and can be combined with in ovo cell proliferation assay by adding EdU (5-ethynyl-2&#180;-deoxyuridine) to the whole embryo at the time of electroporation. The use of green or red fluorescent protein (GFP or RFP) expression plasmids allows the experimenter to quickly determine whether the electroporation successfully targeted the auditory portion of the developing inner ear. In this method paper, representative examples of GFP electroporated specimens are illustrated; embryos were harvested 18 - 96 hr&#160;after electroporation and targeting of GFP to the pro-sensory area of the auditory organ was confirmed by RNA in situ hybridization. The method paper also provides an optimized protocol for the use of the thymidine analog EdU to analyze cell proliferation; an example of an EdU based cell proliferation assay that combines immuno-labeling and click EdU chemistry is provided.

Gene Transfer into the Chicken Auditory Organ by In Ovo Micro-electroporation

The auditory organ mediates hearing. Here we present a modified in ovo micro-electroporation method optimized for studying auditory progenitor cell proliferation and differentiation in the developing chicken auditory organ.

A transferência de genes para o frango auditivo órgão por<em&gt; In Ovo</em&gt; Micro-eletroporação

Chicken embryos are ideal model systems for studying embryonic development as manipulations of gene function can be conducted with relative ease in ovo. ...

A Novel Ex Ovo Banding Technique to Alter Intracardiac Hemodynamics in an Embryonic Chicken System

The new model presented here can be used to understand the influence of hemodynamics on specific cardiac developmental processes, at the cellular and molecular level. To alter intracardiac hemodynamics, fertilized chicken eggs are incubated in a humidified chamber to obtain embryos of the desired stage (HH17). Once this developmental stage is achieved, the embryo is maintained ex ovo and hemodynamics in the embryonic heart are altered by partially constricting the outflow tract (OFT) with a surgical suture at the junction of the OFT and ventricle (OVJ). Control embryos are also cultured ex ovo but are not subjected to the surgical intervention. Banded and control embryos are then incubated in a humidified incubator for the desired period of time, after which 2D ultrasound is employed to analyze the change in blood flow velocity at the OVJ as a result of OFT banding. Once embryos are maintained ex ovo, it is important to ensure adequate hydration in the incubation chamber so as to prevent drying and eventually embryo death. Using this new banded model, it is now possible to perform analyses of changes in the expression of key players involved in valve development and to understand the role of hemodynamics on cellular responses in vivo, which could not be achieved previously.

A Novel Ex Ovo Banding Technique to Alter Intracardiac Hemodynamics in an Embryonic Chicken System

For the first time we present here a reproducible banding procedure to alter hemodynamics in the developing heart ex ovo. This is achieved by partially constricting the outflow tract (OFT).

Um romance<em&gt; Ex Ovo</em&gt; Técnica Banding para Alter intracardíaca Hemodinâmica em um sistema embrionário de galinha

The new model presented here can be used to understand the influence of hemodynamics on specific cardiac developmental processes, at the cellular and ...

An Enzyme- and Serum-free Neural Stem Cell Culture Model for EMT Investigation Suited for Drug Discovery

Epithelial to mesenchymal transition (EMT) describes the process of epithelium transdifferentiating into mesenchyme. EMT is a fundamental process during embryonic development that also commonly occurs in glioblastoma, the most frequent malignant brain tumor. EMT has also been observed in multiple carcinomas outside the brain including breast cancer, lung cancer, colon cancer, gastric cancer. EMT is centrally linked to malignancy by promoting migration, invasion and metastasis formation. The mechanisms of EMT induction are not fully understood. Here we describe an in vitro system for standardized isolation of cortical neural stem cells (NSCs) and subsequent EMT-induction. This system provides the flexibility to use either single cells or explant culture. In this system, rat or mouse embryonic forebrain NSCs are cultured in a defined medium, devoid of serum and enzymes. The NSCs expressed Olig2 and Sox10, two transcription factors observed in oligodendrocyte precursor cells (OPCs). Using this system, interactions between FGF-, BMP- and TGF&#946;-signaling involving Zeb1, Zeb2, and Twist2 were observed where TGF&#946;-activation significantly enhanced cell migration, suggesting a synergistic BMP-/TGF&#946;-interaction. The results point to a network of FGF-, BMP- and TGF&#946;-signaling to be involved in EMT induction and maintenance. This model system is relevant to investigate EMT in vitro. It is cost-efficient and shows high reproducibility. It also allows for the comparison of different compounds with respect to their migration responses (quantitative distance measurement), and high-throughput screening of compounds to inhibit or enhance EMT (qualitative measurement). The model is therefore well suited to test drug libraries for substances affecting EMT.

Epithelial to mesenchymal transition (EMT) allows cancers to become invasive. To investigate EMT, a neural stem cell (NSC)-based in vitro model devoid of serum and enzymes is described. This standardized system allows quantitative and qualitative assessment of cell migration, gene and protein expression. The model is suited for drug discovery.

Um Modelo de enzimas e Cultura de Células-Tronco Neural Serum-livre para EMT Investigation Adequado para Drug Discovery

Epithelial to mesenchymal transition (EMT) describes the process of epithelium transdifferentiating into mesenchyme. EMT is a fundamental process during ...

A Submerged Filter Paper Sandwich for Long-term Ex Ovo Time-lapse Imaging of Early Chick Embryos

Due to its availability, low cost, flat geometry, and transparency, the ex ovo chick embryo has become a major vertebrate animal model for the study of morphogenetic events, such as gastrulation2, neurulation3-5, somitogenesis6, heart bending7,8, and brain formation9-13, during early embryogenesis. Key to understanding morphogenetic processes is to follow them dynamically by time-lapse imaging. The acquisition of time-lapse movies of chick embryogenesis ex ovo has been limited either to short time windows or to the need for an incubator to control temperature and humidity around the embryo14. Here, we present a new technique to culture chick embryos ex ovo for high-resolution time-lapse imaging using transmitted light microscopy. The submerged filter paper sandwich is a variant of the well-established filter paper carrier technique (EC-culture)1 and allows for the culturing of chick embryos without the need for a climate chamber. The embryo is sandwiched between two identical filter paper carriers and is kept fully submerged in a simple, temperature-controlled medium covered by a layer of light mineral oil. Starting from the primitive streak stage (Hamburger-Hamilton stage 5, HH5)15 up to at least the 28-somite stage (HH16)15, embryos can be cultured with either their ventral or dorsal side up. This allows the acquisition of time-lapse movies covering about 30 hr of embryonic development. Representative time-lapse frames and movies are shown. Embryos are compared morphologically to an embryo cultured in the standard EC-culture.
The submerged filter paper sandwich provides a stable environment to study early dorsal and ventral morphogenetic processes. It also allows for live fluorescence imaging and micromanipulations, such as microsurgery, bead implantation, microinjection, gene silencing, and electroporation, and has a strong potential to be combined with immersion objectives for laser-based imaging (including light-sheet microscopy).

A Submerged Filter Paper Sandwich for Long-term Ex Ovo Time-lapse Imaging of Early Chick Embryos

Here, we present a new technique to culture chick embryos ex ovo for time-lapse imaging using transmitted light and fluorescence microscopy. The submerged filter paper sandwich is a variant of the well-established filter paper carrier technique1 that allows for the culturing of chick embryos fully-submerged in a liquid culture medium.

Um Sanduíche papel de filtro submerso por longo prazo<em&gt; Ex Ovo</em&gt; Imagem Time-lapse de galinha precoce embriões

Due to its availability, low cost, flat geometry, and transparency, the ex ovo chick embryo has become a major vertebrate animal model for the study of ...

CRISPR-mediated Loss of Function Analysis in Cerebellar Granule Cells Using In Utero Electroporation-based Gene Transfer

Brain malformation is often caused by genetic mutations. Deciphering the mutations in patient-derived tissues has identified potential causative factors of the diseases. To validate the contribution of a dysfunction of the mutated genes to disease development, the generation of animal models carrying the mutations is one obvious approach. While germline genetically engineered mouse models (GEMMs) are popular biological tools and exhibit reproducible results, it is restricted by time and costs. Meanwhile, non-germline GEMMs often enable exploring gene function in a more feasible manner. Since some brain diseases (e.g., brain tumors) appear to result from somatic but not germline mutations, non-germline chimeric mouse models, in which normal and abnormal cells coexist, could be helpful for disease-relevant analysis. In this study, we report a method for the induction of CRISPR-mediated somatic mutations in the cerebellum. Specifically, we utilized conditional knock-in mice, in which Cas9 and GFP are chronically activated by the CAG (CMV enhancer/chicken &#223;-actin) promoter after Cre-mediated recombination of the genome. The self-designed single-guide RNAs (sgRNAs) and the Cre recombinase sequence, both encoded in a single plasmid construct, were delivered into cerebellar stem/progenitor cells at an embryonic stage using in utero electroporation. Consequently, transfected cells and their daughter cells were labeled with green fluorescent protein (GFP), thus facilitating further phenotypic analyses. Hence, this method is not only showing electroporation-based gene delivery into embryonic cerebellar cells but also proposing a novel quantitative approach to assess CRISPR-mediated loss-of-function phenotypes.

CRISPR-mediated Loss of Function Analysis in Cerebellar Granule Cells Using In Utero Electroporation-based Gene Transfer

Conventional loss-of-function studies of genes using knockout animals have often been costly and time-consuming. Electroporation-based CRISPR-mediated somatic mutagenesis is a powerful tool to understand gene functions in vivo. Here, we report a method to analyze knockout phenotypes in proliferating cells of the cerebellum.

Mediada por CRISPR perda de função de análise no grânulo cerebelar células usando no Utero Electroporation Gene transferência baseada

Brain malformation is often caused by genetic mutations. Deciphering the mutations in patient-derived tissues has identified potential causative factors ...