We would like to thank C. Burns, C. McRae for outlining the basic principle of this purification protocol, and F. Priller for initial implementation of this method in our lab. S.A.-S. is supported by a Heisenberg professorship of the Deutsche Forschungsgemeinschaft (DFG). This work was supported by DFG grant SE2016/7-1.

Este protocolo segue as diretrizes de cuidados de animais da lei alemã e estado de Berlim; manuseio do peixe-zebra foi monitorada pela autoridade local para a protecção dos animais (LaGeSo, Berlin-Brandenburg). 1. A obtenção de embriões Zebrafish para Coração Extração <ol><li> Peixe-zebra repórter cardíaca transversal tal como a Tg (myl7: EGFP) twu34 linha transgénica 9, a fim de se obter os embriões com expressão específica do coração GFP. </li><li> Manter os embriões em água ovo a 28,5 ° C, até a fase embrionária pretendida 10,11. Certifique-se de que a população embrião coletado é homogênea tanto geneticamente e por estágio de desenvolvimento para limitar as variações na expressão gênica. </li><li> Dechorionate os embriões manualmente. </li></ol> 2. Dissecando Zebrafish embrionárias Corações NOTA: Mantenha todas as soluções em gelo. Se possível, fazer o trabalho em equipe: uma pessoa disseca os corações do embtabaco de enrolar enquanto outra pessoa classifica os corações sob a lupa de fluorescência. Isto permite que o tratamento de várias centenas de embriões em algumas horas. <ol><li> Transferir cerca de 100 embriões para um tubo de centrifugação de 1,5 ml. Anestesiar os embriões com tricaína (0,16 mg / ml em meio de E3). Continuar uma vez que os embriões são claramente anestesiados (eles não nadar e sedimentos para o fundo do tubo, mas os seus corações são ainda batendo). </li><li> Remover a solução / E3 tricaina e lavar os embriões, uma vez com 1 ml de L-15/10% de FBS e manter em gelo. NOTA: O meio com FBS a L-15/10% é importante para manter os órgãos e células vivos durante todo o procedimento de dissecção até que os corações foram transferidos para RNAlater ou Trizol. </li><li> Adicionar 1 ml L-15/10% de FBS para os embriões e pipeta cima e para baixo 5-8 vezes com uma rodada Gel Carregando Dica até que a gema é completamente interrompido. Pipetar os embriões gota a gota sobre a superfície da solução, de modo que a queda vai rebentar eos embriões são suavemente interrompido. NOTA: Como vigorosamente e quantas vezes os embriões têm de ser pipetados cima e para baixo depende do estágio de desenvolvimento dos embriões, ou seja, mais de pipetagem é necessária em estágios finais (por exemplo, a 56 hpf). </li><li> Para o primeiro lote de embriões dissecados, avaliar a integridade dos embriões e a proporção de corações dissecados sob microscópio estereoscópico, uma vez que alguns corações podem permanecer solidários com os embriões se pipetaram muito gentilmente. Ajuste o modo de pipetagem para as próximas rodadas de dissecção de acordo. NOTA: Use baixos dicas retenção pipetas e tubos de microcentrífuga para minimizar corações degola ao plástico. </li><li> Aplicar a amostra para um filtro de 100 um colocado em um tubo de 50 ml de centrifugação; enxaguar o tubo de 1,5 mL com 1 mL de meio L-15/10% de FBS e, em seguida, aplicar essa para o filtro, a fim de minimizar a perda da amostra (alguns corações pode ser aderente às paredes do tubo). Lavar o filtro duas vezes com 1 ml de L-15 / 10% de FBS. Neste passo os corações passar através do filtro e são recolhidas no tubo de 50 ml. </li><li> Aplicar o fluxo de passagem para um filtro de 30 mm colocada sobre um tubo de centrifugação de 15 mL e lavar o filtro uma vez com 1 ml de L-15/10% de FBS. Neste segundo passo de filtração, os corações são retidas no filtro e pequenos detritos é lavado. </li><li> Ligue o filtro de cabeça para baixo e lavar os corações para fora do filtro para um 1% de agarose revestidos por placa de Petri por aplicação de três lavagens consecutivas com 1 ml de L-15/10% de FBS. </li><li> Separar manualmente corações GFP positivas a partir dos detritos embrionário não fluorescente (por exemplo, lentes oculares) com um par de pinças sob um estereomicroscópio fluorescência e concentrá-las no centro do prato. Recolha-os de acordo com a etapa 3. NOTA: Se os embriões são mais velhos do que 24 hpf, o coração deve ser de bater, o que indica que os tecidos ainda estão fisiologicamente normal. </li></ol> 3. Isolamento de mRNA a partir de dissecçãoted Corações <ol><li> Recolha os corações no menor volume possível (por exemplo, 10 ul) e pipeta em um tubo de 1,5 ml contendo 0,75 ml RNAlater (no gelo). Verifique se não há corações permanecer na ponta da pipeta por vê-lo sob um microscópio estereoscópico fluorescência. </li><li> Como alternativa, se um capuz químico está disponível nas imediações de um microscópio de fluorescência, transferir os corações coletados em Trizol (CUIDADO) sob o capô química. Isto evita a possível perda de corações que furam na ponta da pipeta e também durante a centrifugação dos corações (passos 3.4, 3.5 e 3.7). Reúnem-se os corações de várias rodadas de isolamento no mesmo tubo com Trizol e ir diretamente para a etapa 3.8; o volume final não deve exceder 10% do volume inicial de Trizol. NOTA: Leia a Ficha de Segurança Trizol Produto (FDSP) antes do uso. Pega reagente Trizol sob um capuz e desgaste recomendado Equipamento de Proteção Individual. Evitar o contacto com a pele, olhos e clothing. Remova todas as fontes de ignição. </li><li> Reúnem-se os corações de várias rondas de isolamento no mesmo tubo com RNAlater (em gelo), como a eficiência de isolamento de ARN aumenta com a quantidade de tecido recolhido. Se o volume total da amostra for superior a 10% do volume inicial RNAlater, utilizar um tubo adicional com 0,75 ml RNAlater para armazenamento (em gelo). </li><li> Centrifuga-se as amostras a 15.700 xg durante 20 min a 4 ° C para sedimentar os corações. </li><li> Sob um microscópio estereoscópico de fluorescência, recolher cuidadosamente, tanto sobrenadante quanto possível num revestidos por placa de Petri de agarose 1% contendo 3 ml de L-15/10% de FBS, mas não perturbe os corações sedimentadas no fundo do tubo de centrifugação. Uma vez que até 15% dos corações pode permanecer no sobrenadante devido à elevada viscosidade do RNAlater, recuperá-los, tal como descrito na etapa 3.7. </li><li> Dentro de uma câmara química, adicionar 0,5 ml de Trizol para o tubo contendo os corações sedimentadas e manter em gelo. </li><li> Sob o microsco fluorescentepe, transferir os corações (a partir do passo 3.5) a partir do 1% de agarose revestidas de prato contendo solução de FBS RNAlater / L-15/10% em outro prato revestido de agarose a 1% com 3 ml de L-15/10% de FBS para diluir a RNAlater. Recolher os corações no centro da placa de petri e transferi-las num volume pequeno para o tubo de corações sedimentados em Trizol sob uma coifa química. </li><li> Vortex o tubo de 1,5 ml contendo os corações em Trizol para interromper o coração e incubar durante 5 min à temperatura ambiente. </li><li> Dentro de uma câmara química, adicione 100 clorofórmio ul (CUIDADO), misturar bem e transferir a solução / clorofórmio Trizol em um 1,5 ml pré-fiado tubo PLG (centrífuga 30 segundos a velocidade máxima antes de usar). Incuba-se durante 3 minutos à temperatura ambiente. NOTA: Leia as MSDS clorofórmio antes de usar. Pega reagente clorofórmio, sob um capuz e desgaste recomendado Equipamento de Proteção Individual. Evitar o contacto com a pele, olhos e vestuário. Manter longe de incompatíveis, como os metais, álcalis. </li><li> Centrifuge a amostra a 15.700 xg durante 15 min a 4 ° C, e transferir a fase aquosa para um novo tubo de 1,5 ml. </li><li> Junte 5-10 ug de glicogénio e 250 pi pré-arrefecida (-20 ° C) isopropanol; misturar bem e incubar durante a noite a -20 ° C. </li><li> Centrifuga-se a amostra a 15.700 xg durante 30 min a 4 ° C e desprezar o sobrenadante. </li><li> Lava-se a pelete com 1 ml de etanol a 75%, centrifugar a 15.700 xg durante 15 min a 4 ° C e desprezar o sobrenadante. </li><li> Deixe evaporar o etanol por secagem do sedimento à temperatura ambiente até se tornar branco (por exemplo, para 10-15 min). </li><li> Adicionar 20 ul de ARNase isento de ddH2O para o sedimento e incubar durante 10-15 min a 55 ° C para dissolver o ARN; em seguida, manter em gelo. </li><li> Avaliar a concentração de ARN e pureza por medição de absorvância. Avaliar a integridade do RNA por a execução da amostra sobre um gel de agarose a 1%. </li></ol>

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The authors have nothing to disclose.

Este protocolo permite o rápido enriquecimento do tecido do coração embrionário do peixe-zebra por análises de expressão de genes. A quantidade e qualidade da amostra de RNA específico cardíaca depende muito de alguns passos cruciais: primeiro, a quantidade da amostra é muito melhor se a perda de corações é impedida em cada etapa do protocolo, uma vez que a purificação RNA só funcionará com suficiente material de partida. Em segundo lugar, a pureza da amostra, o que depende inteiramente do experimentador...

Peixe-zebra (Danio rerio) é amplamente usada na biologia do desenvolvimento para estudar a organogénese in vivo, devido à sua rápida, transparente e extra-uterina do desenvolvimento embrionário, combinada com o tamanho pequeno e a disponibilidade de linhas repórter transgénicos com expressão específica para um tecido de proteínas fluorescentes. Este pequeno vertebrado é particularmente adequado para estudar o desenvolvimento do coração, já que oxigenação do embrião de peixe-zebra cedo não depende de batimento cardíaco e fluxo sanguíneo; esses recursos permitiram a caracterização de um grande número de mutantes cardiovasculares 1,2 e o peixe-zebra é agora um organismo modelo amplamente reconhecido para estudar doenças cardíacas 3. Para estudar a expressão de genes durante o desenvolvimento embrionário, as transcrições são comumente analisados ​​por todo o monte de hibridização in situ (DESEJO) 4, RT-qPCR 5, 6 microarrays, ou sequenciamento de próxima geração (RNA-Seq) 7. EnquantoDESEJO permite uma análise espacial-temporal da expressão gênica dentro de todo o embrião, níveis de transcrição são geralmente avaliada por RT-qPCR, microarrays ou abordagens de RNA-Seq. No entanto, estes métodos requerem enriquecimento tecido específico para perfil de expressão gênica. Uma vez que o coração embrionário do peixe-zebra representa uma pequena fracção da totalidade do embrião, estudos transcriptoma durante o desenvolvimento cardíaco requerem um protocolo de dissecção e enriquecimento de corações. Além disso, para obter dados fisiologicamente relevantes, é importante para manter o tecido cardíaco totalmente funcional até a extracção de ARN. Aqui, descrevemos um protocolo para isolar rapidamente fisiologicamente normal e corações batendo de centenas de embriões de peixes-zebra para se obter eficiência amostras de RNA de alta qualidade para análises posteriores. O presente método é baseado no protocolo descrito por Burns e MacRae, 2006 8. Para o enriquecimento de tecido cardíaco, ambos os métodos de usar uma linha de miocárdio repórter transgénicoe tirar vantagem das propriedades de adesão diferencial de corações de peixes-zebra embrionários contra outros tecidos. Resumidamente, por pipetagem muitos embriões cima e para baixo através de uma ponteira estreita, corações são simultaneamente lançado a partir de corpos embrionárias e, posteriormente, separados dos restos embrionários em duas etapas de filtração rápida; corações marcados com fluorescência são então classificadas manualmente a partir de detritos remanescentes e recolhidos para posterior processamento.

<table><tbody><tr><td>Equipment for raising fish and collecting eggs&amp;nbsp;</td><td></td><td></td><td>see the Zebrafish Book&lt;sup&gt;11&lt;/sup&gt; for details</td></tr><tr><td>Fluorescence stereomicroscope</td><td></td><td></td><td></td></tr><tr><td>Refrigerated Microcentrifuge</td><td></td><td></td><td></td></tr><tr><td>UV-Spectrophotometer</td><td></td><td></td><td>&lt;em&gt;e.g.&lt;/em&gt; Thermo Scientific Nanodrop 2000</td></tr><tr><td>Nucleic acid electrophoresis chamber</td><td></td><td></td><td></td></tr><tr><td>Petri dishes 4 cm &amp;Oslash;, coated with 1% agarose in E3 medium</td><td></td><td></td><td></td></tr><tr><td>Micropipettes and tips (P20, P100, P1000)</td><td></td><td></td><td></td></tr><tr><td>1.5 ml centrifugation tubes</td><td></td><td></td><td></td></tr><tr><td>15 ml and 50 ml centrifugation tubes</td><td></td><td></td><td></td></tr><tr><td>Pair of Dumont #5 forceps</td><td></td><td></td><td></td></tr><tr><td>ExactaCruz&amp;trade; Round Gel Loading Tips in Sterile Rack, 1-200&amp;mu;l&amp;nbsp;</td><td>Santa Cruz</td><td>sc-201732</td><td></td></tr><tr><td>100 &amp;mu;m filter (BD Falcon 100 mm Cell Strainer)</td><td>BD Biosciences</td><td>352360</td><td></td></tr><tr><td>30 &amp;mu;m filter (Pre-Separation Filters-30 &amp;micro;m)</td><td>Miltenyi Biotec</td><td>130-041-407</td><td></td></tr><tr><td>Phase lock gel, heavy, 1.5 ml tubes&amp;nbsp;</td><td>Prime</td><td>2302810</td><td></td></tr><tr><td>Egg water medium</td><td></td><td></td><td>60 &amp;mu;g/ml Instant Ocean Sea Salts in ddH2O, 0.00001% (w/v) Methylene Blue</td></tr><tr><td>E3 medium&amp;nbsp;</td><td></td><td></td><td>5 mM NaCl, 0.17 mM KCl, 0.33 mM CaCl&lt;sub&gt;2&lt;/sub&gt;, 0.33 mM MgSO&lt;sub&gt;4&lt;/sub&gt;</td></tr><tr><td>Tricaine (3-amino benzoic acidethylester)</td><td>Sigma-Aldrich</td><td>A-5040</td><td>4 mg/ml Tricaine stock solution, pH 7</td></tr><tr><td>1% agarose (in E3 medium)</td><td></td><td></td><td></td></tr><tr><td>1% agarose gel (in TBE buffer)</td><td></td><td></td><td></td></tr><tr><td>Leibovitz&amp;acute;s L-15 medium&amp;nbsp;</td><td>Gibco</td><td>21083-027</td><td></td></tr><tr><td>FBS (Fetal Bovine Serum)</td><td>Sigma</td><td>F4135</td><td></td></tr><tr><td>RNAlater</td><td>Ambion</td><td>AM7020</td><td></td></tr><tr><td>Trizol</td><td>Ambion</td><td>1559606</td><td></td></tr><tr><td>Glycogen&amp;nbsp;</td><td>Invitrogen</td><td>10814-010</td><td>20 &amp;micro;g/&amp;micro;l in RNase-free water</td></tr><tr><td>chloroform</td><td></td><td></td><td></td></tr><tr><td>isopropanol</td><td></td><td></td><td></td></tr><tr><td>75% ethanol (in DEPC-ddH2O)</td><td></td><td></td><td></td></tr><tr><td>Nuclease-free water or sterilized DEPC treated ddH2O</td><td></td><td></td><td></td></tr><tr><td>Nucleic acid loading buffer</td><td></td><td></td><td></td></tr><tr><td>TBE (Tris/Borate/EDTA) buffer for electrophoresis</td><td></td><td></td><td></td></tr></tbody></table>

large-scale zebrafish embryonic heart dissection for transcriptional analysis

O coração embrionário do peixe-zebra é composta de apenas algumas centenas de células, o que representa apenas uma pequena fracção de todo o embrião. Portanto, para evitar o transcriptoma cardíaca de ser mascarado pelo transcriptoma embrionário global, é necessário recolher um número suficiente de corações para análises posteriores. Além disso, como o desenvolvimento do peixe-zebra cardíaca processe rapidamente, a recolha do coração e métodos de extracção de ARN precisa de ser rápido, a fim de assegurar homogeneidade das amostras. Aqui, apresentamos um protocolo de dissecção Manual rápido para a coleta / corações batendo funcionais a partir de embriões de peixes-zebra. Este é um pré-requisito essencial para a extração de RNA cardíaca específica posterior para determinar os níveis de expressão de genes específicos cardíaca por análises de transcriptoma, como em tempo real reação em cadeia da polimerase quantitativa (RT-qPCR). O método baseia-se nas propriedades adesivas diferenciais do coração embrionário do peixe-zebra em comparação com outros tecidos; esta permite a rápida physeparação de Sical cardíaca a partir de tecido extracardiac por uma combinação de fluídico rompimento força de cisalhamento, filtração por etapas e coleta manual de transgênicos corações marcados com fluorescência.

Aqui, descrevemos uma experiência representativa dissecção do coração utilizando o peixe-zebra Tg (myl7: GFP) twu34 linhagem transgênica 9, que expressa a proteína fluorescente verde (GFP) exclusivamente dentro do miocárdio (Fig. 1). Foram coletadas ambos os corações dissecados e dos embriões a partir da qual eles foram derivados a avaliar a pureza da amostra coração. Resumidamente, homozigoto Tg (myl7: GFP) twu34 peixe-zebra 9 foram outcrossed c...

Watch this Scientific Journal Video about Large-scale Zebrafish Embryonic Heart Dissection for Transcriptional Analysis at JoVE.com

Large-scale Zebrafish Embryonic Heart Dissection for Transcriptional Analysis

Para analisar os perfis de expressão de genes cardíacos durante o desenvolvimento do coração de peixe-zebra, o RNA total foi de ser extraído do coração isolado. Aqui, apresentamos um protocolo para a coleta / corações batendo funcionais por um rápido esvaziamento manual a partir de embriões de peixes-zebra para obter mRNA específico cardíaca.

Em larga escala Zebrafish Embryonic Coração de dissecação para a análise transcricional

The zebrafish embryonic heart is composed of only a few hundred cells, representing only a small fraction of the entire embryo. Therefore, to prevent the ...

large-scale-zebrafish-embryonic-heart-dissection-for-transcriptional

Research

JoVE Journal

Developmental Biology

14.3K visualizações.  Max Delbrück Center for Molecular Medicine.  Para analisar os perfis de expressão de genes cardíacos durante o desenvolvimento do coração de peixe-zebra, o RNA total foi de ser extraído do coração isolado. Aqui, apresentamos um protocolo para a coleta / corações batendo funcionais por um rápido esvaziamento manual a partir de embriões de peixes-zebra para obter mRNA específico cardíaca. 

Vídeo: Large-scale Zebrafish Embryonic Heart Dissection for Transcriptional Analysis

Isolation and Characterization of Single Cells from Zebrafish Embryos

The zebrafish (Danio rerio) is a powerful model organism to study vertebrate development. Though many aspects of zebrafish embryonic development have been described at the morphological level, little is known about the molecular basis of cellular changes that occur as the organism develops. With recent advancements in microfluidics and multiplexing technologies, it is now possible to characterize gene expression in single cells. This allows for investigation of heterogeneity between individual cells of specific cell populations to identify and classify cell subtypes, characterize intermediate states that occur during cell differentiation, and explore differential cellular responses to stimuli. This study describes a protocol to isolate viable, single cells from zebrafish embryos for high throughput multiplexing assays. This method may be rapidly applied to any zebrafish embryonic cell type with fluorescent markers. An extension of this method may also be used in combination with high throughput sequencing technologies to fully characterize the transcriptome of single cells. As proof of principle, the relative abundance of cardiac differentiation markers was assessed in isolated, single cells derived from nkx2.5 positive cardiac progenitors. By evaluation of gene expression at the single cell level and at a single time point, the data support a model in which cardiac progenitors coexist with differentiating progeny. The method and work flow described here is broadly applicable to the zebrafish research community, requiring only a labeled transgenic fish line and access to microfluidics technologies.

This protocol describes a method for isolating single cells from zebrafish embryos, enriching for cells of interest, capturing zebrafish cells in microfluidic based single cell multiplex systems, and assessing gene expression from single cells.

Isolamento e caracterização de células individuais de embriões Zebrafish

The zebrafish (Danio rerio) is a powerful model organism to study vertebrate development. Though many aspects of zebrafish embryonic development have been ...

Biologia do Desenvolvimento

Dissection of Larval Zebrafish Gonadal Tissue

Although wild zebrafish possess a ZZ/ZW sex-determination system, domesticated zebrafish have lost the sex chromosome. They utilize a polygenic sex determination system, where several genes distributed throughout the genome collectively determine the sex identities of individual fish. Currently, the genes involved in regulating gonad development and how they work remain elusive. Normally, isolating gonadal tissue is the first step to examine the sex developmental processes. Here, we present a procedure to isolate gonadal tissue from 17 dpf (days post fertilization) and 25 dpf zebrafish larvae. The isolated gonadal tissue may be subsequently examined by morphology and gene expression profiling.

Here, we present a protocol for isolating gonadal tissue of larval zebrafish, which will facilitate investigations of zebrafish sex differentiation and maintenance.

Dissecção de larval Zebrafish gonadal Tissue

Although wild zebrafish possess a ZZ/ZW sex-determination system, domesticated zebrafish have lost the sex chromosome. They utilize a polygenic sex ...

Displacement Analysis of Myocardial Mechanical Deformation (DIAMOND) Reveals Segmental Heterogeneity of Cardiac Function in Embryonic Zebrafish

Zebrafish are increasingly utilized as a model organism for cardiomyopathies and regeneration. Current methods evaluating cardiac function fail to reliably detect segmental mechanics and are not readily feasible in zebrafish. Here we present a semiautomated, open-source method for the quantitative assessment of four-dimensional (4D) segmental cardiac function: displacement analysis of myocardial mechanical deformation (DIAMOND). Transgenic embryonic zebrafish were imaged in vivo using a light-sheet fluorescence microscopy system with 4D cardiac motion synchronization. Acquired 3D digital hearts were reconstructed at end-systole and end-diastole, and the ventricle was manually segmented into binary datasets. Then, the heart was reoriented and isotropically resampled along the true short axis, and the ventricle was evenly divided into eight portions (I&#8211;VIII) along the short axis. Due to the different resampling planes and matrices at end-systole and end-diastole, a transformation matrix was applied for image registration to restore the original spatial relationship between the resampled systolic and diastolic image matrices. After image registration, the displacement vector of each segment from end-systole to end-diastole was calculated based on the displacement of mass centroids in three dimensions (3D). DIAMOND shows that basal myocardial segments adjacent to the atrioventricular canal undergo the highest mechanical deformation and are the most susceptible to doxorubicin-induced cardiac injury. Overall, DIAMOND provides novel insights into segmental cardiac mechanics in zebrafish embryos beyond traditional ejection fraction (EF) under both physiological and pathological conditions.

Displacement Analysis of Myocardial Mechanical Deformation DIAMOND Reveals Segmental Heterogeneity of Cardiac Function in Embryonic Zebrafish

The goal of this protocol is to detail a novel method for the assessment of segmental cardiac function in embryonic zebrafish under both physiological and pathological conditions.

Análise de deslocamento da Deformação Mecânica Miocárdica (DIAMANTE) revela heterogeneidade segmental da função cardíaca em zebrafish embrionário

Zebrafish are increasingly utilized as a model organism for cardiomyopathies and regeneration. Current methods evaluating cardiac function fail to ...

Design and Microinjection of Morpholino Antisense Oligonucleotides and mRNA into Zebrafish Embryos to Elucidate Specific Gene Function in Heart Development

The morpholino oligomer-based knockdown system has been used to identify the function of various gene products through loss or reduced expression. Morpholinos (MOs) have the advantage in biological stability over DNA oligos because they are not susceptible to enzymatic degradation. For optimal effectiveness, MOs are injected into 1-4 cell stage embryos. The temporal efficacy of knockdown is variable, but MOs are believed to lose their effects due to dilution eventually. Morpholino dilution and injection amount should be closely controlled to minimize the occurrence of off-target effects while maintaining on-target efficacy. Additional complementary tools, such as CRISPR/Cas9 should be performed against the target gene of interest to generate mutant lines and to confirm the morphant phenotype with these lines. This article will demonstrate how to design, prepare, and microinject a translation-blocking morpholino against hand2 into the yolk of 1-4 cell stage zebrafish embryos to knockdown hand2 function and rescue these "morphants" by co-injection of mRNA encoding the corresponding cDNA. Subsequently, the efficacy of the morpholino microinjections is assessed by first verifying the presence of morpholino in the yolk (co-injected with phenol red) and then by phenotypic analysis. Moreover, cardiac functional analysis to test for knockdown efficacy will be discussed. Finally, assessing the effect of morpholino-induced blockage of gene translation via western blotting will be explained.

The present protocol describes designing, preparing, and microinjecting a translational-blocking morpholino against a representative cardiac gene; Heart And Neural Crest Derivatives Expressed2 (hand2) into the yolk of newly fertilized zebrafish embryos to knock down gene function. It also shows a transient rescue of these "morphants" by co-injection of mRNA encoding this gene product.

The morpholino oligomer-based knockdown system has been used to identify the function of various gene products through loss or reduced expression.  ...

Light-sheet Fluorescence Microscopy to Capture 4-Dimensional Images of the Effects of Modulating Shear Stress on the Developing Zebrafish Heart

The hemodynamic forces experienced by the heart influence cardiac development, especially trabeculation, which forms a network of branching outgrowths from the myocardium. Genetic program defects in the Notch signaling cascade are involved in ventricular defects such as Left Ventricular Non-Compaction Cardiomyopathy or Hypoplastic Left Heart Syndrome. Using this protocol, it can be determined that shear stress driven trabeculation and Notch signaling are related to one another. Using Light-sheet Fluorescence Microscopy, visualization of the developing zebrafish heart was possible. In this manuscript, it was assessed whether hemodynamic forces modulate the initiation of trabeculation via Notch signaling and thus, influence contractile function occurs. For qualitative and quantitative shear stress analysis, 4-D (3-D+time) images were acquired during zebrafish cardiac morphogenesis, and integrated light-sheet fluorescence microscopy with 4-D synchronization captured the ventricular motion. Blood viscosity was reduced via gata1a-morpholino oligonucleotides (MO) micro-injection to decrease shear stress, thereby, down-regulating Notch signaling and attenuating trabeculation. Co-injection of Nrg1 mRNA with gata1a MO rescued Notch-related genes to restore trabeculation. To confirm shear stress driven Notch signaling influences trabeculation, cardiomyocyte contraction was further arrested via tnnt2a-MO to reduce hemodynamic forces, thereby, down-regulating Notch target genes to develop a non-trabeculated myocardium. Finally, corroboration of the expression patterns of shear stress-responsive Notch genes was conducted by subjecting endothelial cells to pulsatile flow. Thus, the 4-D light-sheet microscopy uncovered hemodynamic forces underlying Notch signaling and trabeculation with clinical relevance to non-compaction cardiomyopathy.

Here, we present a protocol to visualize developing hearts in zebrafish in 4-Dimensions (4-D). 4-D imaging, via light-sheet fluorescence microscopy (LSFM), takes 3-Dimensional (3-D) images over time, to reconstruct developing hearts. We show qualitatively and quantitatively that shear stress activates endocardial Notch signaling during chamber development, which promotes cardiac trabeculation.

Microscopia de fluorescência de luz-folha para capturar imagens 4-Dimensional dos efeitos de modulação de tensão de cisalhamento sobre o coração em desenvolvimento de Zebrafish

The hemodynamic forces experienced by the heart influence cardiac development, especially trabeculation, which forms a network of branching outgrowths ...

Bioengenharia

Heart Dissection in Larval, Juvenile and Adult Zebrafish, Danio rerio

Zebrafish have become a beneficial and practical model organism for the study of embryonic heart development (see recent reviews1-6), however, work examining post-embryonic through adult cardiac development has been limited7-10. Examining the changing morphology of the maturing and aging heart are restricted by the lack of techniques available for staging and isolating juvenile and adult hearts. In order to analyze heart development over the fish's lifespan, we dissect zebrafish hearts at numerous stages and photograph them for further analysis11. The morphological features of the heart can easily be quantified and individual hearts can be further analyzed by a host of standard methods. Zebrafish grow at variable rates and maturation correlates better with fish size than age, thus, post-fixation, we photograph and measure fish length as a gauge of fish maturation. This protocol explains two distinct, size dependent dissection techniques for zebrafish, ranging from larvae 3.5mm standard length (SL) with hearts of 100&mu;m ventricle length (VL), to adults, with SL of 30mm and VL 1mm or larger. Larval and adult fish have quite distinct body and organ morphology. Larvae are not only significantly smaller, they have less pigment and each organ is visually very difficult to identify. For this reason, we use distinct dissection techniques.
We used pre-dissection fixation procedures, as we discovered that hearts dissected directly after euthanization have a more variable morphology, with very loose and balloon like atria compared with hearts removed following fixation. The fish fixed prior to dissection, retain in vivo morphology and chamber position (data not shown). In addition, for demonstration purposes, we take advantage of the heart (myocardial) specific GFP transgenic Tg(myl7:GFP)twu34 (12), which allows us to visualize the entire heart and is particularly useful at early stages in development when the cardiac morphology is less distinct from surrounding tissues. Dissection of the heart makes further analysis of the cell and molecular biology underlying heart development and maturation using in situ hybridization, immunohistochemistry, RNA extraction or other analytical methods easier in post-embryonic zebrafish. This protocol will provide a valuable technique for the study of cardiac development maturation and aging.

Heart Dissection in Larval, Juvenile and Adult Zebrafish, Danio rerio

A clear, standardized method for dissection and isolation of the zebrafish heart at multiple developmental stages are described. Annotation and quantification techniques are also discussed.

Dissecção do coração em larval, Zebrafish Juvenil e Adulto, Danio rerio</em

Zebrafish have become a beneficial and practical model organism for the study of embryonic heart development (see recent reviews1-6), however, work ...

Biologia

Immunostaining of Dissected Zebrafish Embryonic Heart 

Zebrafish embryo becomes a popular in vivo vertebrate model for studying cardiac development and human heart diseases due to its advantageous embryology and genetics 1,2. About 100-200 embryos are readily available every week from a single pair of adult fish. The transparent embryos that develop ex utero make them ideal for assessing cardiac defects 3. The expression of any gene can be manipulated via morpholino technology or RNA injection 4. Moreover, forward genetic screens have already generated a list of mutants that affect different perspectives of cardiogenesis 5. 
Whole mount immunostaining is an important technique in this animal model to reveal the expression pattern of the targeted protein to a particular tissue 6. However, high resolution images that can reveal cellular or subcellular structures have been difficult, mainly due to the physical location of the heart and the poor penetration of the antibodies. 
 Here, we present a method to address these bottlenecks by dissecting heart first and then conducting the staining process on the surface of a microscope slide. To prevent the loss of small heart samples and to facilitate solution handling, we restricted the heart samples within a circle on the surface of the microscope slides drawn by an immEdge pen. After the staining, the fluorescence signals can be directly observed by a compound microscope. 
Our new method significantly improves the penetration for antibodies, since a heart from an embryonic fish only consists of few cell layers. High quality images from intact hearts can be obtained within a much reduced procession time for zebrafish embryos aged from day 2 to day 6. Our method can be potentially extended to stain other organs dissected from either zebrafish or other small animals.

Immunostaining of Dissected Zebrafish Embryonic Heart

A rapid way to conduct immunostaining of zebrafish embryonic heart is described. Compared to the whole mount immunostaining approach, this method dramatically increases the penetration of the antibodies, which allows obtaining high resolution images that reveal cellular/subcellular structures in the heart within a much reduced processing time.

Imunomarcação de Dissecada Coração Zebrafish embrionárias

Zebrafish embryo becomes a popular in vivo vertebrate model for studying cardiac development and human heart diseases due to its advantageous embryology ...

Recovery of Adult Zebrafish Hearts for High-throughput Applications

Use of the zebrafish model system for studying development, regeneration, and disease is expanding toward use of adult hearts for cell dissociation and purification of RNA, DNA, and proteins. All of these applications demand the rapid recovery of significant numbers of zebrafish hearts to avoid gene regulatory, metabolic, and other changes that begin after death. Adult zebrafish hearts are also required for studying heart structure for a variety of mutants and for studying heart regeneration. However, the traditional zebrafish heart dissection is slow and difficult and requires specialized tools, making large-scale dissection of adult zebrafish hearts tedious. Traditional methods also harbor the risk of damaging the heart during the dissection. Here, we describe a method for dissection of adult zebrafish hearts that is fast, reproducible, and preserves heart architecture. Furthermore, this method does not require specialized tools, is painless for the zebrafish, can be performed on fresh or fixed specimens, and can be performed on zebrafish as young as one month old. The approach described expands the use of adult zebrafish for cardiovascular research.

Use of zebrafish for cardiovascular research is expanding towards research on adult hearts. For these applications, quick and simple isolation of cardiac tissues is key to avoid post-mortem changes and to obtain an adequate number of samples. Here, we describe a fast and reproducible method for dissecting adult zebrafish hearts.

Recuperação de Zebrafish Adulto Corações para aplicações de alto rendimento

Use of the zebrafish model system for studying development, regeneration, and disease is expanding toward use of adult hearts for cell dissociation and ...

Light Sheet Microscopy of Fast Cardiac Dynamics in Zebrafish Embryos

Embryonic cardiac research has greatly benefited from advances in fast in vivo light sheet fluorescence microscopy (LSFM). Combined with the rapid external development, tractable genetics, and translucency of the zebrafish, Danio rerio, LSFM has delivered insights into cardiac form and function at high spatial and temporal resolution without significant phototoxicity or photobleaching. Imaging of beating hearts challenges existing sample preparation and microscopy techniques. One needs to maintain a healthy sample in a constricted field of view and acquire ultrafast images to resolve the heartbeat. Here we describe optimized tools and solutions to study the zebrafish heart in vivo. We demonstrate the applications of bright transgenic lines for labeling the cardiac constituents and present novel gentle embedding and immobilization techniques that avoid developmental defects and changes in heart rate. We also propose a data acquisition and analysis pipeline adapted to cardiac imaging. The entire workflow presented here focuses on zebrafish embryonic heart imaging but can also be applied to various other samples and experiments.

We describe optimized tools to study the zebrafish heart in vivo with light sheet fluorescence microscopy. Specifically, we suggest bright cardiac transgenic lines and present new gentle embedding and immobilization techniques that avoid developmental and heart defects. A possible data acquisition and analysis pipeline adapted to cardiac imaging is also provided.

Microscopia de Folha de Luz da Dinâmica Cardíaca Rápida em Embriões de Zebrafish

Embryonic cardiac research has greatly benefited from advances in fast in vivo light sheet fluorescence microscopy (LSFM). Combined with the rapid ...

CRISPR-Cas9-Mediated Precise Knock-In Edits in Zebrafish Hearts

Clustered regularly interspaced short palindromic repeats (CRISPR) in animal models enable precise genetic manipulation for the study of physiological phenomena. Zebrafish have been used as an effective genetic model to study numerous questions related to heritable disease, development, and toxicology at the whole-organ and -organism level. Due to the well-annotated and mapped zebrafish genome, numerous tools for gene editing have been developed. However, the efficacy of generating and ease of detecting precise knock-in edits using CRISPR is a limiting factor. Described here is a CRISPR-Cas9-based knock-in approach with the simple detection of precise edits in a gene responsible for cardiac repolarization and associated with the electrical disorder, Long QT Syndrome (LQTS). This two-single-guide RNA (sgRNA) approach excises and replaces the target sequence and links a genetically encoded reporter gene. The utility of this approach is demonstrated by describing non-invasive phenotypic measurements of cardiac electrical function in wild-type and gene-edited zebrafish larvae. This approach enables the efficient study of disease-associated variants in a whole organism. Furthermore, this strategy offers possibilities for the insertion of exogenous sequences of choice, such as reporter genes, orthologs, or gene editors.

This protocol describes an approach to facilitate precise knock-in edits in zebrafish embryos using CRISPR-Cas9 technology. A phenotyping pipeline is presented to demonstrate the applicability of these techniques to model a Long QT Syndrome-associated gene variant.

Edições de knock-in precisas mediadas por CRISPR-Cas9 em corações de peixe-zebra

Clustered regularly interspaced short palindromic repeats (CRISPR) in animal models enable precise genetic manipulation for the study of physiological ...