Damos las gracias a Ekaterina Karelina para ayudar con la grabación de la banda sonora para el vídeo, Ivan Molotkov de animación en 3D y el Dr. Peter Blaesse de CAG-EGFP preparación de plásmidos. El trabajo fue apoyado por becas del Centro de Movilidad Internacional de Finlandia, Fundación Cultural de Finlandia y la Academia de Finlandia.

1. Introducción La creación de animales transgénicos es un poderoso método de investigación de las funciones de genes en animales vivos y un mecanismo para desentrañar la enfermedad de 2,3, así como para la manipulación de las propiedades de las células 4. Sin embargo, el procedimiento es bastante laboriosa, extremadamente largo y costoso, por lo que justifica el uso de métodos alternativos de entrega de genes virales como la inyección de 5, la inyección ventricular neonatal con la electroporación 6 y en el útero de la electroporación 7,8. El método de post-natal no ventricular inyección y electroporación tiene un conjunto único de ventajas: uso de no-viral construcciones genéticas; posibilidad de crear un patrón de expresión locales en el área de interés, en la transfección in situ de los tipos de células no migratorias, por ejemplo cortical astrocitos. En este vídeo, se demuestra el procedimiento detallado de la entrega de genes en el cerebro postnatal de ratas recién nacidos con un plásmido que codifica para el aumento de proteína verde fluorescente bajo el promotor de actina de pollo beta con el CMV potenciador (pCAG-EGFP) 9. Nos ilustran la preparación de la solución inyectable que contienen el plásmido, la fabricación de pipetas de vidrio delgado y montaje de la microinyector en un instrumento estereotáxico. Luego hablamos de anestesiar las crías de rata con isoflurano, sobre la realización de la cirugía, sobre el procedimiento de inyección y de la electroporación utilizando pinzas y electrodos en vivo del evaporador. Finalmente, se analiza brevemente los resultados esperados perspectivas, y las dificultades que puedan surgir durante estos experimentos. 2. Preparación del plásmido para la electroporación <ol><li> Por lo general, preparar 10 l de la solución de inyección de plásmido en un tubo de 200 l de pared delgada. Esta solución es suficiente para varios experimentos. </li><li> Mezclamos 8 l de la solución del plásmido (ver materiales y equipos), con un l de la 10X PBS (ver materiales y equipos) y 1 l de rápida solución al 0,1% de agua verde (ver Materiales y equipo). </li><li> La concentración final del plásmido en la solución inyectable debe ser entre 1 y 3 mg / l. Las menores concentraciones de ADN de plásmido se reducirá la eficiencia de transfección, mientras que la concentración de ADN mayor será demasiado viscoso para inyección a través de la punta fina de capilares de vidrio. </li></ol> 3. Preparación de la aguja de vidrio <ol><li> Para la preparación pipeta de vidrio, se utiliza vidrio de borosilicato con un filamento capilar (ver Materiales y equipo) y un extractor de electrodo de vidrio vertical (ver Materiales y equipo) en tracción máxima y calefacción parámetros. </li><li> A continuación, romper la punta de la pipeta con un pedazo de papel para lograr una punta de 10 a 20 micras de diámetro. </li><li> Comprobamos el diámetro de la punta y forma bajo el objetivo del microscopio. </li></ol> 4. Microinyector Montaje <ol><li> El uso de un polímero fino capilar (ver Materiales y equipo) que llene aproximadamente 1 / 3 del volumen de una jeringa de 10 l Hamilton (ver Materiales y equipo) con aceite mineral (ver Materiales y equipo). Evite las burbujas de aire! </li><li> Luego llene la pipeta de cristal con aceite mineral e insertar la pipeta en la jeringa Hamilton. Evite las burbujas de aire! </li><li> La jeringa con pipeta se fija en el microinyector conectado a un controlador (ver Materiales y equipo). </li><li> La configuración de microinyección fija en un instrumento estereotáxico (ver Materiales y equipo) que nos permite sumergirse de forma segura la punta de la pipeta de vidrio en el tubo con la solución de inyección de plásmido. </li><li> Cuando la punta toca la superficie de la solución, sumergirla mm más de 1 o 2 y llenar la pipeta con aproximadamente 1 l de la mezcla de la inyección con inyector de la micro controlador. </li></ol> 5. Anestesiar animales Todos los procedimientos que aquí se presenta se realizó de acuerdo a los reglamentos de la Universidad de Helsinki para los experimentos con animales. <ol><li> Para cada experimento, se llena una jeringa hermética (ver materiales y equipos), con aproximadamente 2 ml de isoflurano (ver Materiales y equipo). </li><li> Que la jeringa se fija en la unidad de anestesia (ver materiales y equipos) conectada a la fuente de flujo de aire, la caja de los animales y la máscara de configuración fija en estereotáctica. </li><li> En la unidad de anestesia, que se ajusta el flujo de aire a aproximadamente 250 ml / min y el nivel de isoflurano al 4%. </li><li> Ponemos la crías de rata en la caja de los animales durante 2-5 minutos. </li><li> Cuando el cachorro deja de moverse, lugar sobre el cojín eléctrico (ver materiales y equipos) unido a la configuración estereotáctica. </li><li> Colocar una parte rostral de la cabeza del cachorro en la máscara anestésica. </li><li> Se tarda de 5 a 10 minutos para lacachorro para entrar en la anestesia profunda. </li><li> Compruebe profundidad de anestesia con un poco de cola y disminuir la afluencia de isoflurano a alrededor de 1,5 a 2,0%. </li></ol> 6. La cirugía, la microinyección y electroporación <ol><li> El tratamiento de la piel de la cría de cabeza con el 70% de etanol. </li><li> Utilizando unas tijeras pequeñas (ver materiales y equipos) y las pinzas finas (ver materiales y equipos), cortar la piel de una piel del cachorro a su frente. </li><li> Doblar piezas de piel hacia los lados y tire de las barras del oído poco en los orificios auditivos del cráneo de la cabeza y la fijación de la piel. </li><li> El uso de un microscopio binocular, ubicamos el punto bregma en el cráneo. </li><li> Identificar la región de interés, utilizando las coordenadas estereotácticas. </li><li> La posición de la pipeta de inyección, por encima de esta región y se marca por caer 25-50 nl de la solución inyectable sobre la superficie del cráneo. </li><li> Perforar el cráneo con cuidado y suavidad en el punto marcado con un taladro de alta velocidad quirúrgica (ver Materiales y equipo) bajo el microscopio hasta que el líquido aparece en el área perforada. </li><li> Fijar una pinza electropotation electrodos (ver materiales y equipos) en los laterales del cráneo con gel conductor de corriente (ver Materiales y equipos) para lograr una mejor conductividad. </li><li> Eliminar la caída de líquido de la perforación con tampón pequeños (ver materiales y equipos) y sumergir la aguja de vidrio en el agujero de acuerdo a las coordenadas del sitio de la inyección. </li><li> Infundir 25 a 100 nl de la solución inyectable a razón de 5 a 20 nl / seg. </li><li> Quite rápidamente la pipeta y electroporar inmediatamente. La electroporación se realiza mediante la aplicación de cinco pulsos rectángulo con la duración de 50 ms y una amplitud de 99 V en la frecuencia de 1 Hz. </li><li> Retire los electrodos y barras de oído. </li><li> Coser la piel cortada usando una combinación de una pinza de tonto (ver materiales y equipos) y afilado e hilos quirúrgicos (ver Materiales y equipo). </li><li> Coloque el perrito en la cámara de calentamiento durante 15-30 minutos para ayudar a su recuperación después de la anestesia. </li><li> A continuación, poner la parte de atrás de la jaula de las crías de su madre. </li></ol> 7. Resultados representante La expresión del transgén en las células transfectadas con éxito aparecerá aproximadamente 10 horas después de la electroporación, y que se mantendrá estable durante varias semanas. Nos microinyección del plásmido o en capas profundas de la corteza o la región del estriado después del día 2 (P2) crías de ratas Wistar y se realizó en la electroporación in vivo como se describió anteriormente. Rebanadas de cerebro (400 micras de espesor) fueron cortadas después de 2 a 6 días (P4-P8) con un vibrotome en medio frío corte (Hepes buffer solución salina balanceada de Earle) 10. La adquisición de imágenes se realizó con Zeiss Axioplan 2 LSM5 Pascal microscopio confocal (Zeiss, Alemania) en el medio de corte a temperatura ambiente. Los puntos de inyección en profundidad las capas corticales y el cuerpo estriado contiene muchas células transfectadas que expresan EGFP que se encuentra en una región compacta de aproximadamente 200 a 300 micras de diámetro (fig. 1A, B). Dentro de las células transfectadas, el nivel de expresión EGFP es lo suficientemente alta para permitir imágenes de fina procesos celulares (fig. 1C), incluyendo las dendritas de espinas de diferentes formas (Figura 1D) y los paquetes axón (Figura 1). La estabilidad robusta de EGFP, así como la viabilidad celular después de la electroporación permite el rastreo partes distales de los axones (hasta 1,5-2 mm de cuerpos celulares) tales como terminales de cortical (Figura 1 F). <img src="/files/ftp_upload/2244/2244fig1.jpg" alt="Figura 1" /> Figura 1. (A) con éxito las células transfectadas en la región del estriado del cerebro de ratas P4 delinear el sitio de la inyección del plásmido. (B) Las células transfectadas en profundas capas corticales (aproximadamente 1000 m debajo de la superficie cortical) de cerebro de rata P5. (C) una célula transfectada en la región del estriado del cerebro de rata P8. (D) los procesos dendríticos de las células transfectadas en la región del estriado del cerebro de rata P8, las flechas indican los diferentes tipos de espinas dendríticas y filopodios. (E) Los axones de las células transfectadas en vía colateral. (F) Los axones terminan en la superficie pial de la corteza de rata P8 (cabeza de flecha). Las barras de escala son 100 m en A, B, E y F, 10 m en C y D.

<ol>
	<li>Gerlai, R., Clayton, N. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analyzing+hippocampal+function+in+transgenic+mice:+an+ethological+perspective.+Trends+Neurosci.">Analyzing hippocampal function in transgenic mice: an ethological perspective. Trends Neurosci.</a> 22, 47-51 (1999).</li><li>McGowan, E., Eriksen, J., Hutton, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+decade+of+modeling+Alzheimer's+disease+in+transgenic+mice.">A decade of modeling Alzheimer's disease in transgenic mice.</a> Trends Genet. 2, 281-289 (2006).</li><li>Cryan, J. F., Holmes, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+ascent+of+mouse:+advances+in+modeling+human+depression+and+anxiety.">The ascent of mouse: advances in modeling human depression and anxiety.</a> Nat. Rev. Drug Discov. 4, 775-790 (2005).</li><li>Wells, T., Carter, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+engineering+of+neural+function+in+transgenic+rodents:+towards+a+comprehensive+strategy.">Genetic engineering of neural function in transgenic rodents: towards a comprehensive strategy.</a> J. Neurosci. Methods. 108, 111-130 (2001).</li><li>Pilpel, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=reproducible+transduction+of+select+forebrain+regions+by+targeted+recombinant+virus+injection+into+the+neonatal+mouse+brain.">reproducible transduction of select forebrain regions by targeted recombinant virus injection into the neonatal mouse brain.</a> J. Neurosci. 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M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+of+organotypic+hippocampal+slice+cultures:+interface+method.">Preparation of organotypic hippocampal slice cultures: interface method.</a> Nat. Protoc. 1, 1439-1445 (2006).</li><li>Walantus, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+utero+intraventricular+injection+and+electroporation+of+E15+mouse+embryos.">In utero intraventricular injection and electroporation of E15 mouse embryos.</a> J. Vis. 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Métodos de administración de genes en el cerebro de los roedores que viven están bien establecidos en el útero de la electroporación 7,8,11,12 y, más recientemente, para la electroporación postnatal 6. Sin embargo, estos métodos se basan en la inyección intraventricular de ADN plásmido, que puede ser limitante para varias aplicaciones. Por ejemplo, estos métodos no permiten atacar a las células en ciertas áreas cerebrales como el hipocampo, ni la transfección de estos tipos d...

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>2A-sa dumb Tweezers, 115mm</td>
<td>equipment</td>
<td>XYtronic</td>
<td>XY-2A-SA</td>
<td>Treat with 70% ethanol for disinfection before use in surgical manipulations</td>
</tr>
<tr>
<td>Biological Temperature Controller with stainless steel heating pad</td>
<td>equipment</td>
<td>Supertech</td>
<td>TMP-5b</td>
<td>&nbsp;</td>
<tr>
<td>Borosilicate tube with filament</td>
<td>material</td>
<td>Sutter Instruments</td>
<td>BF120-69-10</td>
<td>Glass needle</td>
</tr>
<tr>
<td>Disposable drills</td>
<td>material</td>
<td>Meisinger</td>
<td>HP 310 104 001 001 008</td>
<td>&nbsp;</td>
<tr>
<td>Dulbeco's PBS 10X</td>
<td>reagent</td>
<td>Sigma</td>
<td>D1408</td>
<td>&nbsp;</td>
<tr>
<td>Dumont #5 forceps, 110 mm</td>
<td>equipment</td>
<td>FST</td>
<td>91150-20</td>
<td>Treat with 70% ethanol for disinfection before use in surgical manipulations</td>
</tr>
<tr>
<td>Ealing microelectrode puller</td>
<td>equipment</td>
<td>Ealing</td>
<td>50-2013</td>
<td>Vertical electrode glass puller</td>
</tr>
<tr>
<td>Ethilon monofil polyamide 6-0 FS-3 16 mm 3/8c</td>
<td>material</td>
<td>Johnson &amp; Johnson Medical</td>
<td>EH7177H</td>
<td>Surgical threads</td>
</tr>
<tr>
<td>Exmire micro syringe 10.0 ml</td>
<td>equipment</td>
<td>Exmire</td>
<td>MS*GLLX00</td>
<td>Gas-tight syringe</td>
</tr>
<tr>
<td>Fast Green</td>
<td>reagent</td>
<td>Sigma</td>
<td>F7252</td>
<td>&nbsp;</td>
<tr>
<td>Forceps electrodes</td>
<td>equipment</td>
<td>BEX</td>
<td>LF650P3</td>
<td>Treat with 70% ethanol for disinfection prior to use</td>
</tr>
<tr>
<td>Foredom drill control</td>
<td>equipment</td>
<td>Foredom </td>
<td>FM3545</td>
<td>Surgical drill power supply and control. Currently available analogue is micromotor kit K.1070 (Foredom) </td>
</tr>
<tr>
<td>Foredom micro motor handpiece</td>
<td>equipment</td>
<td>Foredom</td>
<td>MH-145</td>
<td>Currently available analogue is micromotor kit K.1070 (Foredom)</td>
</tr>
<tr>
<td>Gas anesthesia platform for mice</td>
<td>equipment</td>
<td>Stoelting</td>
<td>50264</td>
<td>Assembled on stereotaxic instrument</td>
</tr>
<tr>
<td>Isoflurane</td>
<td>reagent</td>
<td>Baxter</td>
<td>FDG9623</td>
<td>&nbsp;</td>
<tr>
<td>Micro dressing forceps, 105 mm</td>
<td>equipment</td>
<td>Aesculap</td>
<td>BD302R</td>
<td>Treat with 70% ethanol for disinfection before use in surgical manipulations</td>
</tr>
<tr>
<td>Microfil</td>
<td>material</td>
<td>WPI</td>
<td>MF34G-5</td>
<td>Micro syringe filling capillaries</td>
</tr>
<tr>
<td>Mineral oil</td>
<td>reagent</td>
<td>Sigma</td>
<td>M8410</td>
<td>&nbsp;</td>
<tr>
<td>NanoFil Syringe 10 microliter</td>
<td>equipment</td>
<td>WPI</td>
<td>NANOFIL</td>
<td>Hamilton syringe</td>
</tr>
<tr>
<td>plasmid CAG-EGFP</td>
<td>reagent</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>Extracted and purified with EndoFree Plasmid Maxi Kit (Qiagen) and dissolved in nuclease free water to concentration 1.5 mg/ml</td>
</tr>
<tr>
<td>Pulse generator CUY21Vivo-SQ</td>
<td>equipment</td>
<td>BEX</td>
<td>CUY21Vivo-SQ</td>
<td>&nbsp;</td>
<tr>
<td>Schiller electrode gel</td>
<td>reagent</td>
<td>Schiller AG</td>
<td>2.158000</td>
<td>Conductive gel</td>
</tr>
<tr>
<td>Small animal stereotaxic instrument</td>
<td>equipment</td>
<td>David Kopf Instruments</td>
<td>900</td>
<td>&nbsp;</td>
<tr>
<td>Stoelting mouse and neonatal rat adaptor</td>
<td>equipment</td>
<td>Stoelting</td>
<td>51625</td>
<td>Assembled on stereotaxic instrument.
Treat earbars with 70% ethanol for disinfection before use in surgical manipulations</td>
</tr>
<tr>
<td>Student iris scissors, straight 11.5 cm</td>
<td>equipment</td>
<td>FST</td>
<td>91460-11</td>
<td>Treat with 70% ethanol for disinfection before use in surgical manipulations</td>
</tr>
<tr>
<td>Sugi absorbent swabs 17 x 8 mm</td>
<td>material</td>
<td>Kettenbach</td>
<td>31602</td>
<td>Surgical tampons</td>
</tr>
<tr>
<td>UMP3 microsyringe pump and Micro 4 microsyringe pump controller</td>
<td>equipment</td>
<td>WPI</td>
<td>UMP3-1</td>
<td>Microinjector and controller</td>
</tr>
<tr>
<td>Univentor 400 Anesthesia Unit</td>
<td>equipment</td>
<td>Univentor</td>
<td>8323001</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

gene delivery to postnatal rat brain by non-ventricular plasmid injection and electroporation

La creación de animales transgénicos es un método estándar en el estudio de las funciones de un gen de interés en vivo. Sin embargo, muchos nocaut o animales transgénicos no son viables en los casos en que se expresa el gen modificado o suprimido en todo el organismo. Por otra parte, una variedad de mecanismos de compensación a menudo hacen difícil interpretar los resultados. Los efectos de compensación puede ser aliviado por tanto tiempo la expresión del gen o limitar la cantidad de células transfectadas. El método de post-natal no ventricular microinyección y electroporación in vivo permite la ejecución selectiva de los genes, o siRNA moléculas de colorante directamente a una pequeña región de interés en el cerebro de roedores recién nacidos. En contraste con la técnica convencional de inyección ventricular, este método permite la transfección de los tipos de células no migratorias. Animales transfectadas mediante el método descrito aquí puede ser usado, por ejemplo, de dos fotones de imágenes in vivo o en experimentos electrofisiológicos en rebanadas de cerebro agudo.

Watch this Scientific Journal Video about Gene Delivery to Postnatal Rat Brain by Non-ventricular Plasmid Injection and Electroporation at JoVE.com

Gene Delivery to Postnatal Rat Brain by Non-ventricular Plasmid Injection and Electroporation

Este protocolo describe un método no viral de la entrega de las construcciones genéticas en un área determinada del cerebro de roedor viviente. El método consiste en la preparación de plásmidos, fabricación micropipeta, la cirugía de las crías de rata neonatal, la microinyección de la construcción, y<em&gt; In vivo</em&gt; Electroporación.

Gen de entrega de cerebro de rata postnatal por la inyección no ventricular plásmido y electroporación

Creation of transgenic animals is a standard approach in studying functions of a gene of interest in vivo. However, many knockout or transgenic animals ...

gene-delivery-to-postnatal-rat-brain-non-ventricular-plasmid

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JoVE Journal

Neuroscience

15.0K vistas.  University of Helsinki. Este protocolo describe un método no viral de la entrega de las construcciones genéticas en un área determinada del cerebro de roedor viviente. El método consiste en la preparación de plásmidos, fabricación micropipeta, la cirugía de las crías de rata neonatal, la microinyección de la construcción, y In vivo Electroporación.

Video: Gene Delivery to Postnatal Rat Brain by Non-ventricular Plasmid Injection and Electroporation

In utero Electroporation followed by Primary Neuronal Culture for Studying Gene Function in Subset of Cortical Neurons

In vitro study of primary neuronal cultures allows for quantitative analyses of neurite outgrowth. In order to study how genetic alterations affect neuronal process outgrowth, shRNA or cDNA constructs can be introduced into primary neurons via chemical transfection or viral transduction. However, with primary cortical cells, a heterogeneous pool of cell types (glutamatergic neurons from different layers, inhibitory neurons, glial cells) are transfected using these methods. The use of in utero electroporation to introduce DNA constructs in the embryonic rodent cortex allows for certain subsets of cells to be targeted: while electroporation of early embryonic cortex targets deep layers of the cortex, electroporation at late embryonic timepoints targets more superficial layers. Further, differential placement of electrodes across the heads of individual embryos results in the targeting of dorsal-medial versus ventral-lateral regions of the cortex. Following electroporation, transfected cells can be dissected out, dissociated, and plated in vitro for quantitative analysis of neurite outgrowth. Here, we provide a step-by-step method to quantitatively measure neuronal process outgrowth in subsets of cortical cells.
The basic protocol for in utero electroporation has been described in detail in two other JoVE articles from the Kriegstein lab 1, 2. We will provide an overview of our protocol for in utero electroporation, focusing on the most important details, followed by a description of our protocol that applies in utero electroporation to the study of gene function in neuronal process outgrowth.

In utero Electroporation followed by Primary Neuronal Culture for Studying Gene Function in Subset of Cortical Neurons

In utero electroporation is a valuable method for transfecting neuronal progenitor cells in vivo. Depending upon the placement of the electrodes and the developmental timepoint of electroporation, certain subsets of cortical cells can be targeted. Targeted cells can then be analyzed in vivo or in vitro for effects of genetic alteration.

En el útero de electroporación seguido por cultivos neuronales primarias para estudiar la función génica en el subconjunto de neuronas corticales

In vitro study of primary neuronal cultures allows for quantitative analyses of neurite outgrowth. In order to study how genetic alterations affect ...

Investigación

Neurociencias

Mosaic Analysis of Gene Function in Postnatal Mouse Brain Development by Using Virus-based Cre Recombination

Normal brain function relies not only on embryonic development when major neuronal pathways are established, but also on postnatal 
development when neural circuits are matured and refined. Misregulation at this stage may lead to neurological and psychiatric disorders such as autism 
and schizophrenia1,2. Many genes have been studied in the prenatal brain and found crucial to many developmental processes3-5. However, their 
function in the postnatal brain is largely unknown, partly because their deletion in mice often leads to lethality during neonatal development, and partly because their requirement in early development hampers the postnatal analysis. To overcome these obstacles, floxed alleles of these genes are currently being generated in mice 6. When combined with transgenic alleles that express Cre recombinase in specific cell types, conditional deletion can be achieved to study gene function in the postnatal brain. However, this method requires additional alleles and extra time (3-6 months) to generate the mice with appropriate genotypes, thereby limiting the expansion of the genetic analysis to a large scale in the mouse brain.
Here we demonstrate a complementary approach that uses virally-expressed Cre to study these floxed alleles rapidly and 
systematically in postnatal brain development. By injecting recombinant adeno-associated viruses (rAAVs)7,8 encoding Cre into the neonatal brain, 
we are able to delete the gene of interest in different regions of the brain. By controlling the viral titer and coexpressing a fluorescent 
protein marker, we can simultaneously achieve mosaic gene inactivation and sparse neuronal labeling. This method bypasses the requirement of 
many genes in early development, and allows us to study their cell autonomous function in many critical processes in postnatal brain development,
 including axonal and dendritic growth, branching, and tiling, as well as synapse formation and refinement. This method has been used successfully 
in our own lab (unpublished results) and others8,9, and can be extended to other viruses, such as lentivirus 9, as well as to the expression of 
shRNA or dominant active proteins 10. Furthermore, by combining this technique with electrophysiology as well as recently-developed optical 
imaging tools 11, this method provides a new strategy to study how genetic pathways influence neural circuit development and function in mice 
and rats.

An in vivo method to test gene function in postnatal brain is described. Recombinant AAVs expressing Cre and/or a fluorescent protein are injected into neonatal mouse brain. Mosaic gene inactivation and sparse neuronal labeling are achieved, allowing rapid analysis of gene function in processes critical to neural circuit development.

Mosaico de Análisis de la función de genes en el desarrollo postnatal del cerebro del ratón mediante el uso de virus basada en la recombinación Cre

Normal brain function relies not only on embryonic development when major neuronal pathways are established, but also on postnatal 
development when ...

Efficient Gene Delivery into Multiple CNS Territories Using In Utero Electroporation

The ability to manipulate gene expression is the cornerstone of modern day experimental embryology, leading to the elucidation of multiple developmental pathways. Several powerful and well established transgenic technologies are available to manipulate gene expression levels in mouse, allowing for the generation of both loss- and gain-of-function models. However, the generation of mouse transgenics is both costly and time consuming. Alternative methods of gene manipulation have therefore been widely sought. In utero electroporation is a method of gene delivery into live mouse embryos1,2 that we have successfully adapted3,4. It is largely based on the success of in ovo electroporation technologies that are commonly used in chick5. Briefly, DNA is injected into the open ventricles of the developing brain and the application of an electrical current causes the formation of transient pores in cell membranes, allowing for the uptake of DNA into the cell. In our hands, embryos can be efficiently electroporated as early as embryonic day (E) 11.5, while the targeting of younger embryos would require an ultrasound-guided microinjection protocol, as previously described6. Conversely, E15.5 is the latest stage we can easily electroporate, due to the onset of parietal and frontal bone differentiation, which hampers microinjection into the brain. In contrast, the retina is accessible through the end of embryogenesis. Embryos can be collected at any time point throughout the embryonic or early postnatal period. Injection of a reporter construct facilitates the identification of transfected cells.
To date, in utero electroporation has been most widely used for the analysis of neocortical development1,2,3,4. More recent studies have targeted the embryonic retina7,8,9 and thalamus10,11,12. Here, we present a modified in utero electroporation protocol that can be easily adapted to target different domains of the embryonic CNS. We provide evidence that by using this technique, we can target the embryonic telencephalon, diencephalon and retina. Representative results are presented, first showing the use of this technique to introduce DNA expression constructs into the lateral ventricles, allowing us to monitor progenitor maturation, differentiation and migration in the embryonic telencephalon. We also show that this technique can be used to target DNA to the diencephalic territories surrounding the 3rd ventricle, allowing the migratory routes of differentiating neurons into diencephalic nuclei to be monitored. Finally, we show that the use of micromanipulators allows us to accurately introduce DNA constructs into small target areas, including the subretinal space, allowing us to analyse the effects of manipulating gene expression on retinal development.

Efficient Gene Delivery into Multiple CNS Territories Using In Utero Electroporation

In utero electroporation allows for rapid gene delivery in a spatially- and temporally-controlled manner in the developing central nervous system (CNS). Here we describe a highly adaptable in utero electroporation protocol that can be used to deliver expression constructs into multiple embryonic CNS domains, including the telencephalon, diencephalon and retina.

Entrega génica eficaz en los territorios del SNC múltiples utilizando In Utero La electroporación

The ability to manipulate gene expression is the cornerstone of modern day experimental embryology, leading to the elucidation of multiple developmental ...

Mouse in Utero Electroporation: Controlled Spatiotemporal Gene Transfection

In order to understand the function of genes expressed in specific region of the developing brain, including signaling molecules and axon guidance molecules, local gene transfer or knock- out is required. Gene targeting knock-in or knock-out into local regions is possible to perform with combination with a specific CRE line, which is laborious, costly, and time consuming. Therefore, a simple transfection method, an in utero electroporation technique, which can be performed with short time, will be handy to test the possible function of candidate genes prior to the generation of transgenic animals 1,2. In addition to this, in utero electroporation targets areas of the brain where no specific CRE line exists, and will limit embryonic lethality 3,4. Here, we present a method of in utero electroporation combining two different types of electrodes for simple and convenient gene transfer into target areas of the developing brain. First, a unique holding method of embryos using an optic fiber optic light cable will make small embryos (from E9.5) visible for targeted DNA solution injection into ventricles and needle type electrodes insertion to the targeted brain area 5,6. The patterning of the brain such as cortical area occur at early embryonic stage, therefore, these early electroporation from E9.5 make a big contribution to understand entire area patterning event. Second, the precise shape of a capillary prevents uterine damage by making holes by insertion of the capillary. Furthermore, the precise shape of the needle electrodes are created with tungsten and platinum wire and sharpened using sand paper and insulated with nail polish 7, a method which is described in great detail in this protocol. This unique technique allows transfection of plasmid DNA into restricted areas of the brain and will enable small embryos to be electroporated. This will help to, open a new window for many scientists who are working on cell differentiation, cell migration, axon guidance in very early embryonic stage. Moreover, this technique will allow scientists to transfect plasmid DNA into deep parts of the developing brain such as thalamus and hypothalamus, where not many region-specific CRE lines exist for gain of function (GOF) or loss of function (LOF) analyses.

Mouse in Utero Electroporation: Controlled Spatiotemporal Gene Transfection

A gene transfer method into the developing mouse brain is described by using a unique surgical method and special shape of electrodes. This unique technique allows transfection of plasmid DNA temporally and spatially, which will aid many neuroscientists in studying brain development.

Del ratón en el útero de electroporación: Transefection controlada Gene espacio-temporal

In order to understand the function of genes expressed in specific region of the developing brain, including signaling molecules and axon guidance ...

Gene Transfer to the Developing Mouse Inner Ear by In Vivo Electroporation

The mammalian inner ear has 6 distinct sensory epithelia: 3 cristae in the ampullae of the semicircular canals; maculae in the utricle and saccule; and the organ of Corti in the coiled cochlea. The cristae and maculae contain vestibular hair cells that transduce mechanical stimuli to subserve the special sense of balance, while auditory hair cells in the organ of Corti are the primary transducers for hearing 1. Cell fate specification in these sensory epithelia and morphogenesis of the semicircular canals and cochlea take place during the second week of gestation in the mouse and are largely completed before birth 2,3. Developmental studies of the mouse inner ear are routinely conducted by harvesting transgenic embryos at different embryonic or postnatal stages to gain insight into the molecular basis of cellular and/or morphological phenotypes 4,5. We hypothesize that gene transfer to the developing mouse inner ear in utero in the context of gain- and loss-of-function studies represents a complimentary approach to traditional mouse transgenesis for the interrogation of the genetic mechanisms underlying mammalian inner ear development6.
The experimental paradigm to conduct gene misexpression studies in the developing mouse inner ear demonstrated here resolves into three general steps: 1) ventral laparotomy; 2) transuterine microinjection; and 3) in vivo electroporation. Ventral laparotomy is a mouse survival surgical technique that permits externalization of the uterus to gain experimental access to the implanted embryos7. Transuterine microinjection is the use of beveled, glass capillary micropipettes to introduce expression plasmid into the lumen of the otic vesicle or otocyst. In vivo electroporation is the application of square wave, direct current pulses to drive expression plasmid into progenitor cells8-10. 
We previously described this electroporation-based gene transfer technique and included detailed notes on each step of the protocol11. Mouse experimental embryological techniques can be difficult to learn from prose and still images alone. In the present work, we demonstrate the 3 steps in the gene transfer procedure. Most critically, we deploy digital video microscopy to show precisely how to: 1) identify embryo orientation in utero; 2) reorient embryos for targeting injections to the otocyst; 3) microinject DNA mixed with tracer dye solution into the otocyst at embryonic days 11.5 and 12.5; 4) electroporate the injected otocyst; and 5) label electroporated embryos for postnatal selection at birth. We provide representative examples of successfully transfected inner ears; a pictorial guide to the most common causes of otocyst mistargeting; discuss how to avoid common methodological errors; and present guidelines for writing an in utero gene transfer animal care protocol.

Gene Transfer to the Developing Mouse Inner Ear by In Vivo Electroporation

The mouse inner ear is a placode-derived sensory organ whose developmental program is elaborated during gestation. We define an in utero gene transfer technique consisting of three steps: mouse ventral laparotomy, transuterine microinjection, and in vivo electroporation. We use digital video microscopy to demonstrate the critical experimental embryological techniques.

Transferencia de genes a la oreja del ratón en desarrollo por el interior<em&gt; En Vivo</em&gt; La electroporación

The mammalian inner ear has 6 distinct sensory epithelia: 3 cristae in the ampullae of the semicircular canals; maculae in the utricle and saccule; and ...

Expansion of Embryonic and Adult Neural Stem Cells by In Utero Electroporation or Viral Stereotaxic Injection

Somatic stem cells can divide to generate additional stem cells (expansion) or more differentiated cell types (differentiation), which is fundamental for tissue formation during embryonic development and tissue homeostasis during adulthood 1. Currently, great efforts are invested towards controlling the switch of somatic stem cells from expansion to differentiation because this is thought to be fundamental for developing novel strategies for regenerative medicine 1,2. However, a major challenge in the study and use of somatic stem cell is that their expansion has been proven very difficult to control.
Here we describe a system that allows the control of neural stem/progenitor cell (altogether referred to as NSC) expansion in the mouse embryonic cortex or the adult hippocampus by manipulating the expression of the cdk4/cyclinD1 complex, a major regulator of the G1 phase of the cell cycle and somatic stem cell differentiation 3,4. Specifically, two different approaches are described by which the cdk4/cyclinD1 complex is overexpressed in NSC in vivo. By the first approach, overexpression of the cell cycle regulators is obtained by injecting plasmids encoding for cdk4/cyclinD1 in the lumen of the mouse telencephalon followed by in utero electroporation to deliver them to NSC of the lateral cortex, thus, triggering episomal expression of the transgenes 5-8. By the second approach, highly concentrated HIV-derived viruses are stereotaxically injected in the dentate gyrus of the adult mouse hippocampus, thus, triggering constitutive expression of the cell cycle regulators after integration of the viral construct in the genome of infected cells 9. Both approaches, whose basic principles were already described by other video protocols 10-14, were here optimized to i) reduce tissue damage, ii) target wide portions of very specific brain regions, iii) obtain high numbers of manipulated cells within each region, and iv) trigger high expression levels of the transgenes within each cell. Transient overexpression of the transgenes using the two approaches is obtained by different means i.e. by natural dilution of the electroporated plasmids due to cell division or tamoxifen administration in Cre-expressing NSC infected with viruses carrying cdk4/cyclinD1 flanked by loxP sites, respectively 9,15.
These methods provide a very powerful platform to acutely and tissue-specifically manipulate the expression of any gene in the mouse brain. In particular, by manipulating the expression of the cdk4/cyclinD1 complex, our system allows the temporal control of NSC expansion and their switch to differentiation, thus, ultimately increasing the number of neurons generated in the mammalian brain. Our approach may be critically important for basic research and using somatic stem cells for therapy of the mammalian central nervous system while providing a better understanding of i) stem cell contribution to tissue formation during development, ii) tissue homeostasis during adulthood, iii) the role of adult neurogenesis in cognitive functions, and perhaps, iv) better using somatic stem cells in models of neurodegenerative diseases.

Expansion of Embryonic and Adult Neural Stem Cells by In Utero Electroporation or Viral Stereotaxic Injection

Controlling the expansion of somatic stem cells is a major factor hampering their study and use in therapy. Here we describe a system to temporally control neural stem cells expansion during development and adulthood, which can be used to increase the number of neurons generated in the mouse brain.

La expansión de las células madre embrionarias y adultas neurales por<em&gt; In Utero</em&gt; La electroporación o inyección estereotáxica Viral

Somatic stem cells can divide to generate additional stem cells (expansion) or more differentiated cell types (differentiation), which is fundamental for ...

In vivo Postnatal Electroporation and Time-lapse Imaging of Neuroblast Migration in Mouse Acute Brain Slices

The subventricular zone (SVZ) is one of the main neurogenic niches in the postnatal brain. Here, neural progenitors proliferate and give rise to neuroblasts able to move along the rostral migratory stream (RMS) towards the olfactory bulb (OB). This long-distance migration is required for the subsequent maturation of newborn neurons in the OB, but the molecular mechanisms regulating this process are still unclear. Investigating the signaling pathways controlling neuroblast motility may not only help understand a fundamental step in neurogenesis, but also have therapeutic regenerative potential, given the ability of these neuroblasts to target brain sites affected by injury, stroke, or degeneration.
In this manuscript we describe a detailed protocol for in vivo postnatal electroporation and subsequent time-lapse imaging of neuroblast migration in the mouse RMS. Postnatal electroporation can efficiently transfect SVZ progenitor cells, which in turn generate neuroblasts migrating along the RMS. Using confocal spinning disk time-lapse microscopy on acute brain slice cultures, neuroblast migration can be monitored in an environment closely resembling the in vivo condition. Moreover, neuroblast motility can be tracked and quantitatively analyzed. As an example, we describe how to use in vivo postnatal electroporation of a GFP-expressing plasmid to label and visualize neuroblasts migrating along the RMS. Electroporation of shRNA or CRE recombinase-expressing plasmids in conditional knockout mice employing the LoxP system can also be used to target genes of interest. Pharmacological manipulation of acute brain slice cultures can be performed to investigate the role of different signaling molecules in neuroblast migration. By coupling in vivo electroporation with time-lapse imaging, we hope to understand the molecular mechanisms controlling neuroblast motility and contribute to the development of novel approaches to promote brain repair.

In vivo Postnatal Electroporation and Time-lapse Imaging of Neuroblast Migration in Mouse Acute Brain Slices

Neuroblast migration is a fundamental event in postnatal neurogenesis. We describe a protocol for efficient labeling of neuroblasts by in vivo postnatal electroporation and subsequent visualization of their migration using time-lapse imaging of acute brain slices. We include a description for the quantitative analysis of neuroblast dynamics by video tracking.

In vivo Postnatal electroporación y time-lapse de Neuroblast Migración en rodajas de cerebro de ratón aguda

The subventricular zone (SVZ) is one of the main neurogenic niches in the postnatal brain. Here, neural progenitors proliferate and give rise to ...

Subtype-selective Electroporation of Cortical Interneurons

The study of central nervous system (CNS) maturation relies on genetic targeting of neuronal populations. However, the task of restricting the expression of genes of interest to specific neuronal subtypes has proven remarkably challenging due to the relative scarcity of specific promoter elements. GABAergic interneurons constitute a neuronal population with extensive genetic and morphological diversity. Indeed, more than 11 different subtypes of GABAergic interneurons have been characterized in the mouse cortex1. Here we present an adapted protocol for selective targeting of GABAergic populations. We achieved subtype selective targeting of GABAergic interneurons by using the enhancer element of the homeobox transcription factors Dlx5 and Dlx6, homologues of the Drosophila distal-less (Dll) gene2,3, to drive the expression of specific genes through in utero electroporation.

This procedure shows how to target interneurons in the developing mouse forebrain by means of in utero electroporation. This technique was particularly efficient to achieve selective gene expression in interneuron subtypes destined to the superficial layers of the cortex.

-Subtipo selectivo electroporación de interneuronas corticales

The study of central nervous system (CNS) maturation relies on genetic targeting of neuronal populations. However, the task of restricting the expression ...

Analysis of Gene Expression Changes in the Rat Hippocampus After Deep Brain Stimulation of the Anterior Thalamic Nucleus

Deep brain stimulation (DBS) surgery, targeting various regions of the brain such as the basal ganglia, thalamus, and subthalamic regions, is an effective treatment for several movement disorders that have failed to respond to medication. Recent progress in the field of DBS surgery has begun to extend the application of this surgical technique to other conditions as diverse as morbid obesity, depression and obsessive compulsive disorder. Despite these expanding indications, little is known about the underlying physiological mechanisms that facilitate the beneficial effects of DBS surgery. One approach to this question is to perform gene expression analysis in neurons that receive the electrical stimulation. Previous studies have shown that neurogenesis in the rat dentate gyrus is elicited in DBS targeting of the anterior nucleus of the thalamus1. DBS surgery targeting the ATN is used widely for treatment refractory epilepsy. It is thus of much interest for us to explore the transcriptional changes induced by electrically stimulating the ATN. In this manuscript, we describe our methodologies for stereotactically-guided DBS surgery targeting the ATN in adult male Wistar rats. We also discuss the subsequent steps for tissue dissection, RNA isolation, cDNA preparation and quantitative RT-PCR for measuring gene expression changes. This method could be applied and modified for stimulating the basal ganglia and other regions of the brain commonly clinically targeted. The gene expression study described here assumes a candidate target gene approach for discovering molecular players that could be directing the mechanism for DBS.

The mechanism underlying the therapeutic effects of Deep Brain Stimulation (DBS) surgery needs investigation. The methods presented in this manuscript describe an experimental approach to examine the cellular events triggered by DBS by analyzing the gene expression profile of candidate genes that can facilitate neurogenesis post DBS surgery.

Análisis de los cambios de expresión génica en la Rata Hippocampus Después de la estimulación cerebral profunda del tálamo anterior Núcleo

Deep brain stimulation (DBS) surgery, targeting various regions of the brain such as the basal ganglia, thalamus, and subthalamic regions, is an effective ...

Using Fluorescence Activated Cell Sorting to Examine Cell-Type-Specific Gene Expression in Rat Brain Tissue

The brain is comprised of four primary cell types including neurons, astrocytes, microglia and oligodendrocytes. Though they are not the most abundant cell type in the brain, neurons are the most widely studied of these cell types given their direct role in impacting behaviors. Other cell types in the brain also impact neuronal function and behavior via the signaling molecules they produce. Neuroscientists must understand the interactions between the cell types in the brain to better understand how these interactions impact neural function and disease. To date, the most common method of analyzing protein or gene expression utilizes the homogenization of whole tissue samples, usually with blood, and without regard for cell type. This approach is an informative approach for examining general changes in gene or protein expression that may influence neural function and behavior; however, this method of analysis does not lend itself to a greater understanding of cell-type-specific gene expression and the effect of cell-to-cell communication on neural function. Analysis of behavioral epigenetics has been an area of growing focus which examines how modifications of the deoxyribonucleic acid (DNA) structure impact long-term gene expression and behavior; however, this information may only be relevant if analyzed in a cell-type-specific manner given the differential lineage and thus epigenetic markers that may be present on certain genes of individual neural cell types. The Fluorescence Activated Cell Sorting (FACS) technique described below provides a simple and effective way to isolate individual neural cells for the subsequent analysis of gene expression, protein expression, or epigenetic modifications of DNA. This technique can also be modified to isolate more specific neural cell types in the brain for subsequent cell-type-specific analysis.

The goal of this protocol is to use the fluorescence activated cell sorting (FACS) technique to sort specific types of neural cells for subsequent analysis of cell-type-specific gene expression, epigenetic markers, and or protein expression.

Utilizando fluorescencia clasificación de células activadas para examinar Cell-tipo-específica la expresión génica en el tejido de cerebro de rata

The brain is comprised of four primary cell types including neurons, astrocytes, microglia and oligodendrocytes. Though they are not the most abundant ...