Este trabajo fue apoyado por theNIH grantNS042626. Damos las gracias a Thorn Kurt y UCSF Nikon Imaging centro de asistencia con las imágenes.

1. Preparación de los embriones de pez cebra <ol><li> Dos días antes de la electroporación, creado jaulas de apareamiento de los peces de tipo salvaje con divisores para separar los machos de las hembras. </li><li> Un día antes de la electroporación, tire de los separadores en el apareamiento de las jaulas del día anterior. </li><li> Recoger los embriones e incubar 50 embriones fecundados en el medio de 30 ml que contienen embriones 0,003% feniltiourea (PTU) a 28,5 ° C. </li><li> En el día de la electroporación, dechorionate los embriones de forma manual con unas pinzas finas (5 Inox, Dumont electrónico, Suiza), cuando los embriones llegan a la etapa de desarrollo de 22hpf. Luego, transferir los embriones al 3 de 10ml electroporación Ringer (180 mM NaCl, KCl 5 mM, CaCl2 1,8 mM, 5 mM HEPES pH 7,2) que contiene un 0,003% de PTU. </li><li> Añadir 420 l de valores tricaína (4mg/ml) a la electroporación de 10 ml de Ringer para anestesiar a los embriones. </li></ol> 2. Preparación para la electroporación <ol><li> Agujas de vidrio de la inyección fueron sacados de los capilares (1,2 mm de diámetro exterior, 0,9 mm de diámetro, con filamento) en un extractor de Flaming P897-Brown (Sutter Instruments, Novato, CA, EE.UU.). La punta de la aguja se rompió con las pinzas para obtener una línea de combate, como se muestra en la Figura 1D. El diámetro de la punta debe estar alrededor de 10 micras y el ángulo de inclinación debe ser alrededor de 30 grados. </li><li> Prepare un 0,8% y 1% de bajo punto de fusión de agarosa (Shelton Scientific, Inc. Catálogo # IB70050) en solución de Ringer electroporación. Alícuota de la solución de agarosa en tubos de 2 ml microcentrífuga. Mantener las alícuotas en un bloque de calor a ~ 37 ° C. </li><li> El sistema GAL4/UAS se utiliza para conducir la expresión de genes en las células progenitoras neurales de embriones electroporated. Dos plásmidos se utilizan: plásmido EF1α-GFF-PT2KXIG, en el que Gal4FF es impulsado por el promotor EF1α todas partes, y el plásmido UAS-E1B-EGFP PT2KXIG. </li><li> Prepare EF1α-GFF-PT2KXIG y UAS-E1B-EGFP-PT2KXIG ADN plásmido con GenEluteTM HP plásmido Kit Midiprep (Sigma). </li><li> Los plásmidos se concentra entonces en acetato de sodio / etanol precipitación a la concentración final de 2.1 mg / l en 10 mM Tris Cl (pH 8,5). </li><li> Mezcla de los dos plásmidos y diluir con nucleasa libre de H2O a una concentración final de 500 ng / l para cada plásmido. Además de rojo fenol (diluido volumen 1 / 10 en total) a la solución es el preferido para la visualización de la entrega. Mantenga la solución de ADN en el hielo. </li><li> Justo antes de la electroporación, retrocarga la aguja de inyección con dos l solución de ADN y ajustar el volumen de inyección de 2 nl. </li></ol> 3. Electroporación <ol><li> Un microscopio de disección stero (Zeiss Stemi 2000 con una ampliación máxima de 50x), una presión de inyector de aire (Narishige IM 300 microinyector), dos micromanipulador (WPI M3301R, Instrumentos del Mundo de precisión, Sarasota, FL, EE.UU.), y un estimulador eléctrico (SD9 pulso cuadrado estimulador Grass Tlefactor, West Warwick, Rhode Island, EE.UU.) se configuran como se muestra en la Figura 1. </li><li> Para montar los embriones, se sumergen dos embriones en el 1% bajo punto de fusión de agarosa. Inmediatamente después, la toma de embriones a partir de la agarosa con una pipeta de vidrio. </li><li> Colocar los embriones en una tapa de plástico invertida placa de Petri en gotas individuales de agarosa. Orientar a los embriones con cuidado con una sonda de fibra a una posición dorsal, antes de la agarosa solidifica de manera que el cerebro anterior es accesible tanto para los electrodos y la aguja de microinyección (fig. 1B). Los embriones se debe montar en gotas individuales de agarosa. </li><li> Manipular los electrodos con el micromanipulador izquierda. Introducir los electrodos en la agarosa, como se muestra en la Figura 1B. Electrodos de platino iridio personalizado paralelo bipolar 125 micras de diámetro y espaciados 500 m además se utilizan para la electroporación (FHC, catálogo # PBSA0575). </li><li> Inserte la aguja de microinyección en el ventrículo del cerebro anterior y se inyecta la mezcla de ADN 4nl, como el flujo de líquido de color rojo y la inflamación del ventrículo puede ser observado. </li><li> Inmediatamente, un 28,5 V pulso que dura milisegundos 1 se aplicó de forma manual. Luego invertir la polaridad y aplicar una mayor 28,5 V pulso que dura una milésima de segundo. Esto se traducirá en el etiquetado de mosaico bilateral de las células progenitoras neurales del cerebro anterior. </li><li> Después de la electroporación de 10 embriones, se añade medio de embriones de 5 ml para cubrir los embriones y la cáscara de la agarosa con un cuchillo de microcirugía para liberar los embriones. </li><li> La transferencia de los embriones electroporated a un plato fresco de medio de 30 ml que contienen embriones 0,003% PTU y se incuba a 28,5 º C. </li></ol> 4. Montaje y Time-lapse de imágenes en vivo <ol><li> Unas 4 horas después de la electroporación, la señal de EGFP se puede observar si se observa bajo un microscopio de epifluorescencia de disección. </li><li> Cinco horas después de la electroporación, seleccionar los embriones con un mosaico muy pero la expresión EGFP fuerte en la región del cerebro anterior. </li><li> La transferencia de los embriones seleccionados para 10 ml medio de embriones que contienen 0,003% PTU. </li><li> Añadir 420 l de valores tricaína (4mg/ml) a la 10ml embrionarias medio to anestesiar a los embriones. </li><li> Para montar los embriones, se sumergen en un embrión de bajo punto de fusión del 0,8% de agarosa. A continuación, retire inmediatamente el embrión de la agarosa con una pipeta de vidrio y colocar el embrión en el centro de una placa de cultivo de vidrio de 35 mm de fondo (MatTek corporación, Parte # P35GC-1.5-10-C, <a href="http://www.glass-bottom-dishes.com/">www.glass-bottom-dishes.com</a> ) . </li><li> Orientar a los embriones con cuidado con una sonda de fibra a una posición dorsal, antes de la agarosa solidifica. </li><li> Coloque el plato correctamente en la etapa de control de temperatura del microscopio confocal, tal como se muestra en la figura 1C (Nosotros usamos un microscopio confocal Nikon C1 espectrales con objetivos arriba-derecha). Ajustar la temperatura a 28,5 ° C. </li><li> Añadir 3 ml de medio de 28,5 ° C precalentado embrionario que contiene 0,003% PTU para cubrir el embrión. El embrión ya está listo para la imagen. </li><li> Realizar time-lapse de imágenes en vivo con un intervalo fijo utilizando un objetivo de inmersión de agua. </li></ol> 5. Resultados representante Se muestra en la Figura 2 se seleccionan los marcos de un lapso de tiempo de imagen confocal en vivo de la electroporación de embriones de EF1α-GFF + UAS-E1B-EGFP en 22 HPF. <img src="/files/ftp_upload/2594/2594fig1.jpg" alt="Figura 1" /> Figura 1. Aparato set-up. (A) El montaje de equipos de electroporación: la hierba SD9 estimulador pulso cuadrado (i), el micromanipulador izquierda (ii), los electrodos (iii), el Zeiss microscopio de disección (iv), la aguja de inyección (v), el micromanipulador derecho (vi) y el Narishige IM 300 microinyector (vii). (B) La posición relativa de los electrodos (i), el ventrículo del cerebro anterior (ii) y la aguja de inyección (iii). Tenga en cuenta la solución de ADN de color rojo ha sido inyectado en el ventrículo del cerebro anterior. (C) El montaje de imágenes en vivo en el microscopio Nikon C1 confocal: el controlador de temperatura (i), el agua mojando objetivo len (ii) y el embrión electroporated incrustado en bajo punto de fusión de agarosa en un recipiente de vidrio cultivo de fondo (iii) (D ) de la imagen de una aguja y tiró de corte para la microinyección de ADN. <img src="/files/ftp_upload/2594/2594fig2.jpg" alt="Figura 2" /> Figura 2. Fotogramas seleccionados de un joven de 18 horas de lapso de tiempo de imagen confocal en vivo del embrión electroporated con EF1α-GFF + UAS-E1B-EGFP en 22 HPF. La superficie del ventrículo izquierdo es en la parte inferior de cada cuadro de imagen. Barra de escala representa 10 micras.

<ol>
	<li>Temple, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+development+of+neural+stem+cells.">The development of neural stem cells.</a> Nature. 414, 112-117 (2001).</li><li>G#246;tz, M., Huttner, W. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+cell+biology+of+neurogenesis.">The cell biology of neurogenesis.</a> Nat. Rev. Mol. Cell Biol. 6, 777-788 (2005).</li><li>Cerda, G. A., Thomas, J. E., Allende, M. L., Karlstrom, R. O., Palma, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electroporation+of+DNA,+RNA,+and+morpholinos+into+zebrafish+embryos.">Electroporation of DNA, RNA, and morpholinos into zebrafish embryos.</a> Methods. 39, 207-211 (2006).</li><li>Hendricks, M., Jesuthasan, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electroporation-based+methods+for+in+vivo,+whole+mount+and+primary+culture+analysis+of+zebrafish+brain+development.">Electroporation-based methods for in vivo, whole mount and primary culture analysis of zebrafish brain development.</a> Neural. Dev. 2, 6-6 (2007).</li><li>Tawk, M., Bianco, I. H., Clarke, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Focal+electroporation+in+zebrafish+embryos+and+larvae.">Focal electroporation in zebrafish embryos and larvae.</a> Methods Mol. Biol. 546, 145-151 (2009).</li><li>Tawk, M., Tuil, D., Torrente, Y., Vriz, S., Paulin, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-efficiency+gene+transfer+into+adult+fish:+a+new+tool+to+study+fin+regeneration.">High-efficiency gene transfer into adult fish: a new tool to study fin regeneration.</a> Genesis. 32, 27-31 (2002).</li></ol>

En este vídeo, se demuestra un método para time-lapse en vivo de células progenitoras neurales a nivel clonal en el cerebro anterior pez cebra en desarrollo. Hemos probado y modificar los protocolos existentes electroporación 4-6 a genética y fluorescencia etiqueta individual células progenitoras neurales. Un árbol genealógico compuesto de células de la progenie clonal relación se puede establecer, ya que sólo unas pocas células se marcaron con un poco de tensión relativamente baja de la electrop...

time-lapse live imaging of clonally related neural progenitor cells in the developing zebrafish forebrain

Patrones precisos de la división, migración y diferenciación de las células progenitoras neuronales son cruciales para el desarrollo apropiado del cerebro y 1,2 función. Para entender el comportamiento de las células progenitoras neurales en el complejo en un entorno vivo, time-lapse de imágenes en vivo de las células progenitoras neuronales en un cerebro intacto es críticamente necesario. En este video, explotar las características únicas de embriones de pez cebra para visualizar el desarrollo de las células progenitoras neurales del cerebro anterior en vivo. Usamos la electroporación de genética y escasamente etiqueta individual células progenitoras neurales. En pocas palabras, construcciones de ADN que codifican para los marcadores fluorescentes se inyecta en el ventrículo del cerebro anterior de 22 horas después de la fecundación (HPF) embriones de pez cebra y pulsos eléctricos fueron entregados inmediatamente. Seis horas más tarde, los embriones de pez cebra electroporación fueron montadas con bajo punto de fusión de agarosa en placas de cultivo de fondo de cristal. Marcado con fluorescencia células progenitoras neurales fueron estudiados luego de 36 horas con intervalos fijos con un microscopio confocal con agua sumergiendo la lente objetivo. El presente método proporciona una forma para obtener información sobre el desarrollo en vivo de las células progenitoras neurales del cerebro anterior y se puede aplicar a otras partes del sistema nervioso central del embrión de pez cebra.

Watch this Scientific Journal Video about Time-lapse Live Imaging of Clonally Related Neural Progenitor Cells in the Developing Zebrafish Forebrain at JoVE.com

Time-lapse Live Imaging of Clonally Related Neural Progenitor Cells in the Developing Zebrafish Forebrain

El vídeo de la actualidad muestra un método que aprovecha las ventajas de la combinación de electroporación y la microscopía confocal para realizar las imágenes en vivo en cada células progenitoras neurales en el cerebro anterior pez cebra en desarrollo.<em&gt; En vivo</em&gt; El análisis del desarrollo de las células progenitoras neurales del cerebro anterior a nivel clonal se puede lograr de esta manera.

Time-lapse de imágenes en vivo de la relación clonal con células progenitoras neurales en el cerebro anterior El desarrollo de pez cebra

Precise patterns of division, migration and differentiation of neural progenitor cells are crucial for proper brain development and function1,2. To ...

time-lapse-live-imaging-clonally-related-neural-progenitor-cells

Research

JoVE Journal

Neuroscience

10.1K vistas.  University of California San Francisco. El vídeo de la actualidad muestra un método que aprovecha las ventajas de la combinación de electroporación y la microscopía confocal para realizar las imágenes en vivo en cada células progenitoras neurales en el cerebro anterior pez cebra en desarrollo. En vivo El análisis del desarrollo de las células progenitoras neurales del cerebro anterior a nivel clonal se puede lograr de esta manera.

Video: Time-lapse Live Imaging of Clonally Related Neural Progenitor Cells in the Developing Zebrafish Forebrain

Live-cell Imaging of Sensory Organ Precursor Cells in Intact Drosophila Pupae

Since the discovery of Green Fluorescent Protein (GFP), there has been a revolutionary change in the use of live-cell imaging as a tool for understanding fundamental biological mechanisms. Striking progress has been particularly evident in Drosophila, whose extensive toolkit of mutants and transgenic lines provides a convenient model to study evolutionarily-conserved developmental and cell biological mechanisms. We are interested in understanding the mechanisms that control cell fate specification in the adult peripheral nervous system (PNS) in Drosophila. Bristles that cover the head, thorax, abdomen, legs and wings of the adult fly are individual mechanosensory organs, and have been studied as a model system for understanding mechanisms of Notch-dependent cell fate decisions. Sensory organ precursor (SOP) cells of the microchaetes (or small bristles), are distributed throughout the epithelium of the pupal thorax, and are specified during the first 12 hours after the onset of pupariation. After specification, the SOP cells begin to divide, segregating the cell fate determinant Numb to one daughter cell during mitosis. Numb functions as a cell-autonomous inhibitor of the Notch signaling pathway.
Here, we show a method to follow protein dynamics in SOP cell and its progeny within the intact pupal thorax using a combination of tissue-specific Gal4 drivers and GFP-tagged fusion proteins 1,2.This technique has the advantage over fixed tissue or cultured explants because it allows us to follow the entire development of an organ from specification of the neural precursor to growth and terminal differentiation of the organ. We can therefore directly correlate changes in cell behavior to changes in terminal differentiation. Moreover, we can combine the live imaging technique with mosaic analysis with a repressible cell marker (MARCM) system to assess the dynamics of tagged proteins in mitotic SOPs under mutant or wildtype conditions. Using this technique, we and others have revealed novel insights into regulation of asymmetric cell division and the control of Notch signaling activation in SOP cells (examples include references 1-6,7 ,8).

Live-cell Imaging of Sensory Organ Precursor Cells in Intact Drosophila Pupae

In this video, we describe a method for live cell imaging of asymmetrically dividing sensory organ progenitor cells and epidermal cells in intact Drosophila pupae

Células vivas imágenes de células de los órganos sensoriales Precursor en Intacto Drosophila Las pupas

Since the discovery of Green Fluorescent Protein (GFP), there has been a revolutionary change in the use of live-cell imaging as a tool for understanding ...

Investigación

Neurociencias

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

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

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

Imágenes de alta resolución en vivo del comportamiento de las células en el desarrollo de neuroepitelio

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

Time-lapse Imaging of Neuroblast Migration in Acute Slices of the Adult Mouse Forebrain

There is a substantial body of evidence indicating that new functional neurons are constitutively generated from an endogenous pool of neural stem cells in restricted areas of the adult mammalian brain. Newborn neuroblasts from the subventricular zone (SVZ) migrate along the rostral migratory stream (RMS) to their final destination in the olfactory bulb (OB)1. In the RMS, neuroblasts migrate tangentially in chains ensheathed by astrocytic processes2,3 using blood vessels as a structural support and a source of molecular factors required for migration4,5. In the OB, neuroblasts detach from the chains and migrate radially into the different bulbar layers where they differentiate into interneurons and integrate into the existing network1, 6.
In this manuscript we describe the procedure for monitoring cell migration in acute slices of the rodent brain. The use of acute slices allows the assessment of cell migration in the microenvironment that closely resembling to in vivo conditions and in brain regions that are difficult to access for in vivo imaging. In addition, it avoids long culturing condition as in the case of organotypic and cell cultures that may eventually alter the migration properties of the cells. Neuronal precursors in acute slices can be visualized using DIC optics or fluorescent proteins. Viral labeling of neuronal precursors in the SVZ, grafting neuroblasts from reporter mice into the SVZ of wild-type mice, and using transgenic mice that express fluorescent protein in neuroblasts are all suitable methods for visualizing neuroblasts and following their migration. The later method, however, does not allow individual cells to be tracked for long periods of time because of the high density of labeled cells. We used a wide-field fluorescent upright microscope equipped with a CCD camera to achieve a relatively rapid acquisition interval (one image every 15 or 30 sec) to reliably identify the stationary and migratory phases. A precise identification of the duration of the stationary and migratory phases is crucial for the unambiguous interpretation of results. We also performed multiple z-step acquisitions to monitor neuroblasts migration in 3D. Wide-field fluorescent imaging has been used extensively to visualize neuronal migration7-10. Here, we describe detailed protocol for labeling neuroblasts, performing real-time video-imaging of neuroblast migration in acute slices of the adult mouse forebrain, and analyzing cell migration. While the described protocol exemplified the migration of neuroblasts in the adult RMS, it can also be used to follow cell migration in embryonic and early postnatal brains.

We describe a protocol for real-time videoimaging of neuronal migration in the mouse forebrain. The migration of virally-labeled or grafted neuronal precursors was recorded in acute live slices using wide-field fluorescent imaging with a relatively rapid acquisition interval to study the different phases of cell migration, including the durations of the stationary and migration phases and the speed of migration.

Time-lapse de imágenes de Migración neuroblasto en rodajas agudas del cerebro anterior ratón adulto

There is a substantial body of evidence indicating that new functional neurons are constitutively generated from an endogenous pool of neural stem cells ...

Motor Nerve Transection and Time-lapse Imaging of Glial Cell Behaviors in Live Zebrafish

The nervous system is often described as a hard-wired component of the body even though it is a considerably fluid organ system that reacts to external stimuli in a consistent, stereotyped manner, while maintaining incredible flexibility and plasticity. Unlike the central nervous system (CNS), the peripheral nervous system (PNS) is capable of significant repair, but we have only just begun to understand the cellular and molecular mechanisms that govern this phenomenon. Using zebrafish as a model system, we have the unprecedented opportunity to couple regenerative studies with in vivo imaging and genetic manipulation. Peripheral nerves are composed of axons surrounded by layers of glia and connective tissue. Axons are ensheathed by myelinating or non-myelinating Schwann cells, which are in turn wrapped into a fascicle by a cellular sheath called the perineurium. Following an injury, adult peripheral nerves have the remarkable capacity to remove damaged axonal debris and re-innervate targets. To investigate the roles of all peripheral glia in PNS regeneration, we describe here an axon transection assay that uses a commercially available nitrogen-pumped dye laser to axotomize motor nerves in live transgenic zebrafish. We further describe the methods to couple these experiments to time-lapse imaging of injured and control nerves. This experimental paradigm can be used to not only assess the role that glia play in nerve regeneration, but can also be the platform for elucidating the molecular mechanisms that govern nervous system repair.

Although the peripheral nervous system (PNS) is capable of significant repair after injury, little is known about the cellular and molecular mechanisms that govern this phenomenon. Using live, transgenic zebrafish and a reproducible nerve transection assay, we can study dynamic glial cell behaviors during nerve degeneration and regeneration.

Motor transección del nervio y Time-lapse de imágenes de Conductas de células gliales en el pez cebra en vivo

The  nervous system is often described as a hard-wired component of the body even  though it is a considerably fluid organ system that reacts to external ...

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 ...

Assessing Cell Cycle Progression of Neural Stem and Progenitor Cells in the Mouse Developing Brain after Genotoxic Stress

Neurons of the cerebral cortex are generated during brain development from different types of neural stem and progenitor cells (NSPC), which form a pseudostratified epithelium lining the lateral ventricles of the embryonic brain. Genotoxic stresses, such as ionizing radiation, have highly deleterious effects on the developing brain related to the high sensitivity of NSPC. Elucidation of the cellular and molecular mechanisms involved depends on the characterization of the DNA damage response of these particular types of cells, which requires an accurate method to determine NSPC progression through the cell cycle in the damaged tissue. Here is shown a method based on successive intraperitoneal injections of EdU and BrdU in pregnant mice and further detection of these two thymidine analogues in coronal sections of the embryonic brain. EdU and BrdU are both incorporated in DNA of replicating cells during S phase and are detected by two different techniques (azide or a specific antibody, respectively), which facilitate their simultaneous detection. EdU and BrdU staining are then determined for each NSPC nucleus in function of its distance from the ventricular margin in a standard region of the dorsal telencephalon. Thus this dual labeling technique allows distinguishing cells that progressed through the cell cycle from those that have activated a cell cycle checkpoint leading to cell cycle arrest in response to DNA damage.
An example of experiment is presented, in which EdU was injected before irradiation and BrdU immediately after and analyzes performed within the 4 hr&#160;following irradiation. This protocol provides an accurate analysis of the acute DNA damage response of NSPC in function of the phase of the cell cycle at which they have been irradiated. This method is easily transposable to many other systems in order to determine the impact of a particular treatment on cell cycle progression in living tissues.

Administration of two analogs of thymidine, EdU and BrdU, in pregnant mice allows the analysis of cell cycle progression in neural and progenitor cells in the embryonic mouse brain. This method is useful to determine the effects of genotoxic stress, including ionizing radiation, during brain development.

La evaluación de la progresión del ciclo celular de la madre neurales y células progenitoras en el cerebro en desarrollo del ratón después de estrés genotóxico

Neurons of the cerebral cortex are generated during brain development from different types of neural stem and progenitor cells (NSPC), which form a ...

Live Imaging of Mitosis in the Developing Mouse Embryonic Cortex

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

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

Imágenes en vivo de la mitosis en el desarrollo de la corteza de embriones de ratón

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

Feeder-free Derivation of Neural Crest Progenitor Cells from Human Pluripotent Stem Cells

Human pluripotent stem cells (hPSCs) have great potential for studying human embryonic development, for modeling human diseases in the dish and as a source of transplantable cells for regenerative applications after disease or accidents. Neural crest (NC) cells are the precursors for a large variety of adult somatic cells, such as cells from the peripheral nervous system and glia, melanocytes and mesenchymal cells. They are a valuable source of cells to study aspects of human embryonic development, including cell fate specification and migration. Further differentiation of NC progenitor cells into terminally differentiated cell types offers the possibility to model human diseases in vitro, investigate disease mechanisms and generate cells for regenerative medicine. This article presents the adaptation of a currently available in vitro differentiation protocol for the derivation of NC cells from hPSCs. This new protocol requires 18 days of differentiation, is feeder-free, easily scalable and highly reproducible among human embryonic stem cell (hESC) lines as well as human induced pluripotent stem cell (hiPSC) lines. Both old and new protocols yield NC cells of equal identity.

Neural crest (NC) cells derived from human pluripotent stem cells (hPSC) have great potential for modeling human development and disease and for cell replacement therapies. Here, a feeder-free adaptation of the currently widely used in vitro differentiation protocol for the derivation of NC cells from hPSCs is presented.

Derivación-Feeder libres de Células Progenitoras de la cresta neural Pluripotentes Células Madre

Human pluripotent stem cells (hPSCs) have great potential for studying human embryonic development, for modeling human diseases in the dish and as a ...

Cell Sorting of Neural Stem and Progenitor Cells from the Adult Mouse Subventricular Zone and Live-imaging of their Cell Cycle Dynamics

Neural stem cells (NSCs) in the subventricular zone of the lateral ventricles (SVZ) sustain olfactory neurogenesis throughout life in the mammalian brain. They successively generate transit amplifying cells (TACs) and neuroblasts that differentiate into neurons once they integrate the olfactory bulbs. Emerging fluorescent activated cell sorting (FACS) techniques have allowed the isolation of NSCs as well as their progeny and have started to shed light on gene regulatory networks in adult neurogenic niches. We report here a cell sorting technique that allows to follow and distinguish the cell cycle dynamics of the above-mentioned cell populations from the adult SVZ with a LeX/EGFR/CD24 triple staining. Isolated cells are then plated as adherent cells to explore in details their cell cycle progression by time-lapse video microscopy. To this end, we use transgenic Fluorescence Ubiquitination Cell Cycle Indicator (FUCCI) mice in which cells are red-fluorescent during G1 phase due to a G1 specific red-Cdt1 reporter. This method has recently revealed that proliferating NSCs progressively lengthen their G1 phase during aging, leading to neurogenesis impairment. This method is easily transposable to other systems and could be of great interest for the study of the cell cycle dynamics of brain cells in the context of brain pathologies.

We report a Fluorescent Activated Cell Sorting (FACS)-based method to isolate neural stem cells (NSCs) and their progeny from the subventricular zone (SVZ) of the adult mouse brain. Applied to Fluorescence Ubiquitination Cell Cycle Indicator (FUCCI) transgenic mice, it allows the study of cell cycle progression by live imaging.

Clasificación celular del Neuronales madre y progenitoras Las células del adulto Ratón zona subventricular y Live-imágenes de sus Dinámica del Ciclo Celular

Neural stem cells (NSCs) in the subventricular zone of the lateral ventricles (SVZ) sustain olfactory neurogenesis throughout life in the mammalian brain. ...

Time-lapse Live Imaging and Quantification of Fast Dendritic Branch Dynamics in Developing Drosophila Neurons

Highly motile dendritic filopodia are widely present in neurons at early developmental stages. These exploratory dynamic branches sample the surrounding environment and initiate contacts with potential synaptic partners. Although the connection between dendritic branch dynamics and synaptogenesis is well established, how developmental and activity-dependent processes regulate dendritic branch dynamics is not well understood. This is partly due to the technical difficulties associated with the live imaging and quantitative analyses of these fine structures using an in vivo system. We established a method to study dendrite dynamics using Drosophila larval ventral lateral neurons (LNvs), which can be individually labeled using genetic approaches and are accessible for live imaging. Taking advantage of this system, we developed protocols to capture branch dynamics of the whole dendritic arbor of a single labeled LNv through time-lapse live imaging. We then performed post-processing to improve image quality through drift correction and deconvolution, followed by analyzing branch dynamics at the single-branch level by annotating spatial positions of all branch terminals. Lastly, we developed R scripts (Supplementary File) and specific parameters to quantify branch dynamics using the coordinate information generated by the terminal tracing. Collectively, this protocol allows us to achieve a detailed quantitative description of branch dynamics of the neuronal dendritic arbor with high temporal and spatial resolution. The methods we developed are generally applicable to sparsely labeled neurons in both in vitro and in vivo conditions.

Time-lapse Live Imaging and Quantification of Fast Dendritic Branch Dynamics in Developing Drosophila Neurons

Here, we describe the method we employed to image highly motile dendritic filopodia in a live preparation of the Drosophila larval brain, and the protocol we developed to quantify time-lapse 3D imaging datasets for quantitative assessments of dendrite dynamics in developing neurons.

Imágenes en vivo de lapso de tiempo y cuantificación de la dinámica de ramas dendríticas rápidas en el desarrollo de neuronas drosophila

Highly motile dendritic filopodia are widely present in neurons at early developmental stages. These exploratory dynamic branches sample the surrounding ...