Agradecemos a los miembros de Matsunami de laboratorio para la lectura crítica de este manuscrito.

1. Procedimiento: El procedimiento consta de tres partes completadas en un tiempo total de 3 días: la transferencia de células, transfección y la inmunocitoquímica, un paso llevado a cabo al día. Transferencia y la transfección de células en los dos primeros días se llevó a cabo en condiciones estériles en una cámara de flujo laminar. Día 1: Traslado de las células HEK293T para el ensayo de la superficie de la expresión. <ol><li> Medio de transmisión (M10): Mezclar medio mínimo esencial suplementado con 10% (en volumen) de suero fetal bovino en condiciones estériles. </li><li> Se cultivan las células a una confluencia deseado en una placa de cultivo de 100 mm, dependiendo del número de platos necesarios para configurar. Es importante para determinar la fracción de células que se transfieren para evitar las células cubierto o escasa: por ejemplo, de un 100% confluentes plato de 100 mm, se puede transferir de 3% a un plato de 35 mm para obtener aproximadamente el 30% de confluencia en el este último. </li><li> Antes de la transferencia de células, en la cámara de flujo laminar estéril, capa de 22 X 22 mm se desliza con cubierta de vidrio estéril lisina poli D (1 mg / ml) y colocar una en cada placa de cultivo celular de 35 mm, con revestimiento hacia arriba para las células de revestimiento (Figura 1 ). Deje que la solución se seque durante 5 - 10 minutos. Durante este intervalo, la fuente de UV en la cámara de laminar puede ser activado para esterilizar el cubreobjetos, si lo desea. Poli D lisina ayuda a las células heterólogas se adhieren a la cubierta se desliza. </li><li> Para la transferencia de células, aspirar a los medios de comunicación existentes en la placa de 100 mm, lave cuidadosamente la adición de 8 ml de PBS estéril, aspirar el PBS y trypsinize las células en 3 mL 0,05% de tripsina-EDTA, cuando las células se desprenden de la placa, bloque de reacción enzimática más la adición de 5 ml M10. Triturar las células y la transferencia de volumen requerido para un tubo cónico estéril, centrifugar a 200 g durante 5 minutos para que sedimenten las células. Aspirar a cabo sobrenadante que contiene tripsina-EDTA, dejando el pellet de células intactas. Para transferir las células a placas de 35 mm, añada 1 ml M10 para cada plato y triturar para disociar las células. Añadir 1 ml de las células se resuspendieron a cada plato. Las células se incuban durante la noche a 37 ° C, 5% de CO 2. <img src="/files/ftp_upload/2405/2405fig1.jpg" alt="Figura 1" /> Figura 1. Coat 22 X 22 mm cubreobjetos de vidrio con poli-D de lisina y el lugar estucado por una cara en cada plato de 35 mm. </li></ol> Día 2: La transfección de células HEK293T. <ol><li> 18-24 horas después de la transferencia, las células están listas para la transfección de los receptores a ensayar. El uso de los receptores y RTP1S clonado en el vector de expresión de mamíferos PCI, preparado a partir de cultivos bacterianos utilizando Qiagen Miniprep protocolo Kit se describe a continuación antes de las 4. Use receptores que son etiquetados con terminal N 20 aminoácidos de largo epítopo rodopsina para facilitar la inmunotinción. </li><li> El uso de la construcción de 1000 ng receptor, 250 ng de RTP1S construir y 50 ng de proteína de fluorescencia verde cada transfección. Realizar la transfección utilizando Lipofectamine 2000, según manual del fabricante. </li></ol> Día 3: La inmunocitoquímica para visualizar receptores de las células teñidas superficie. <ol><li> Antes de comenzar, prepare las manchas y soluciones de lavado y enfriamiento a 4 ° C. Tinción medio: medio esencial mínimo, 45 ml, suero fetal bovino, 5 ml; HEPES (1M), 500 l (concentración final 10 mM), azida de sodio (1,5 M), 500 l (concentración final 15 mM). Solución de lavado: HBSS, 500 ml; HEPES (1M), 5 ml (concentración final 10 mM), azida de sodio (1,5 M), 5 ml (concentración final 15 mM). Ambas soluciones pueden ser almacenadas a 4 º C para su reutilización. Preparar las soluciones de anticuerpos mediante la dilución de anticuerpos necesarios en el medio de tinción de 100 veces. </li><li> Inicio inmunoquímica para la tinción de la superficie de los receptores de olor alrededor de 24 horas después de la transfección. Para realizar la tinción de células vivas, el trabajo experimental debe ser enfriado a 4 ° C: llenar un gran contenido de hielo y patrones de la superficie de hielo para que sea lo más uniforme posible, coloque una bandeja en el hielo y rociarlo con el 70% etanol. Cortar un trozo de parafina (más pequeño que la longitud de la bandeja) y colocar en la bandeja de etanol rociado, para obtener una superficie lisa. La transferencia de la cubierta de vidrio que contiene las células transfectadas se desliza sobre la parafina, de uno en uno, lado celda hacia arriba, usando unas pinzas. Cada capa de hoja de cubierta con 100 L solución fría tinción primaria, extrusión cuidadosamente una esquina de la hoja (Figura 2). Después de todas las capas de la cubierta se desliza con una solución de anticuerpos, la cubierta de la bandeja para evitar el secado de la solución en el aire. Llevar a cabo la incubación primaria durante 45-60 minutos. </li><li> Después de la incubación primaria, de forma rápida transferencia de la cubierta se desliza a las placas de cultivo de 35 mm original, que contiene los medios de comunicación. Aspirar los medios de comunicación y agregar 2 ml de solución de lavado enfriado ligeramente desde el borde del plato para evitar la pérdida de las células de la hoja de la cubierta. Aspirar la solución de lavado y repetir dos veces para completar tres lavados. Al final del tercer lavado, no aspirar a la solución de lavado. </li><li> Prepare anticuerpo secundario solutien los medios de tinción y la transferencia de la cubierta se desliza desde la solución de lavado a una capa de parafina recién colocada en la misma bandeja. Una vez más suave extrusión de 100 L de solución de anticuerpos a la capa de cada hoja de la cubierta, desde la esquina, como la incubación primaria. Llevar a cabo la incubación secundaria de 30 a 45 minutos y traslado de regreso a la solución de lavado de la vajilla original de 35 mm. Una vez más, lavar la cubierta se desliza tres veces como se describe. </li><li> Aspirar la solución de lavado de último lavado y añadir 2 ml de paraformaldehído al 1% frío. Fijar las células en una solución fría paraformaldehído al 1%, en hielo durante 15 minutos. </li><li> Monte la cubierta se desliza sobre el cristal de microscopio limpio diapositivas con montaje Mowiol reactivo, con la cara de la celda hacia abajo y con cautela excluir todas las burbujas de aire (Figura 3). Deje secar al aire una vez Mowiol, lavar la cubierta se desliza suavemente por la adición de agua destilada en la superficie y aspirar de inmediato. <img src="/files/ftp_upload/2405/2405fig2.jpg" alt="Figura 2" /> Figura 2. Capa de cada cubreobjetos con 100 L solución fría tinción primaria. <img src="/files/ftp_upload/2405/2405fig3.jpg" alt="Figura 3" /> Figura 3. Montar el cubreobjetos con la cara hacia abajo en la celda de cristal de microscopio limpios diapositivas usando el reactivo de montaje Mowiol. </li></ol> 2. Los resultados representativos: Tinción de células vivas le permite a uno visualizar las proteínas en la superficie de las células, en la transfección de los receptores con los acompañantes (en este caso de los receptores odoríferos Olfr62, con RTP1S receptor de proteína transportadora) (Figura 4). Tinción de la superficie celular de los receptores se caracteriza por el patrón de tinción puntiforme (Figura 4B, el recuadro). Tinción realizado inadecuadamente puede conducir a un mayor ruido, lo que hace difícil para el observador para distinguir las manchas de la superficie real del ruido. <img src="/files/ftp_upload/2405/2405fig4.jpg" alt="Figura 4" /> Transfección Figura 4. De los receptores con chaperones permite la visualización de proteínas en la superficie de las células mediante la tinción de células vivas. Transfección del receptor odorante Olfr62 solo (A) y la transfección de Olfr62 con acompañante RTP1S (B). Los niveles de expresión de GFP servir como control de transfección (A &#39;y B&#39;).

<ol>
	<li>Buck, L., Axel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+multigene+family+may+encode+odorant+receptors:+a+molecular+basis+for+odor+recognition.">A novel multigene family may encode odorant receptors: a molecular basis for odor recognition.</a> Cell. 65, 175-187 (1991).</li><li>Malnic, B., Hirono, J., Sato, T., Buck, L. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combinatorial+receptor+codes+for+odors.">Combinatorial receptor codes for odors.</a> Cell. 96, 713-723 (1999).</li><li>Saito, H., Kubota, M., Roberts, R. W., Chi, Q., Matsunami, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RTP+family+members+induce+functional+expression+of+mammalian+odorant+receptors.">RTP family members induce functional expression of mammalian odorant receptors.</a> Cell. 119, 679-691 (2004).</li><li>Zhuang, H., Matsunami, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluating+cell-surface+expression+and+measuring+activation+of+mammalian+odorant+receptors+in+heterologous+cells.">Evaluating cell-surface expression and measuring activation of mammalian odorant receptors in heterologous cells.</a> Nat Protoc. 3, 1402-1413 (2008).</li></ol>

Cada paso debe ser realizado cuidadosamente para asegurarse de tinción de la superficie importante y distintivo. El proceso de tinción completa debe ser llevado a cabo en frío (sobre hielo), y la bandeja en la que se establecen cubreobjetos debe ser enfriado antes de su uso para asegurar las células sobrevivir. Por otra parte la fijación se realiza al final del proceso de tinción de la superficie. Esto está en agudo contraste con la tinción de interior en el que precede a la fijación de tinción para permeabili...

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<td>Cover slip 22 X 22 mm (#1)</td>
<td>&nbsp;</td>
<td>Thermo Scientific</td>
<td>72200-11</td>
<td>&nbsp;</td>
<tr>
<td>Fetal bovine serum</td>
<td>&nbsp;</td>
<td>Gibco</td>
<td>16000</td>
<td>&nbsp;</td>
<tr>
<td>Lipofectamine 2000</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>11668-019</td>
<td>&nbsp;</td>
<tr>
<td>Minimal essential medium</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>M4655</td>
<td>With L glutamate, Earle&#x2019;s salt and bicarbonate</td>
</tr>
<tr>
<td>Mowiol</td>
<td>&nbsp;</td>
<td>Calbiochem</td>
<td>475904</td>
<td>&nbsp;</td>
<tr>
<td>Paraformaldehyde</td>
<td>&nbsp;</td>
<td>EMS</td>
<td>19208</td>
<td>&nbsp;</td>
<tr>
<td>Hanks Balanced Salt Solution (HBSS) 1X </td>
<td>&nbsp;</td>
<td>Gibco </td>
<td>14025</td>
<td>With calcium chloride and magnesium chloride</td>
</tr>
<tr>
<td>HEPES Buffer Solution</td>
<td>&nbsp;</td>
<td>Gibco</td>
<td>15630</td>
<td>&nbsp;</td>
<tr>
<td>Phosphate Buffer Saline (PBS)</td>
<td>&nbsp;</td>
<td>Cellgro</td>
<td>21-040-CV</td>
<td>Without calcium and magnesium</td>
</tr>
<tr>
<td>Poly D Lysine Hydrobromide</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>P7280</td>
<td>&nbsp;</td>
<tr>
<td>Sodium Azide</td>
<td>&nbsp;</td>
<td>EM Science</td>
<td>SX0299-1</td>
<td>&nbsp;</td>
<tr>
<td>Tissue culture dish 35 X 10 mm</td>
<td>&nbsp;</td>
<td>Falcon</td>
<td>353801</td>
<td>&nbsp;</td>
<tr>
<td>Trypsin-EDTA </td>
<td>&nbsp;</td>
<td>Gibco</td>
<td>25300</td>
<td>0.05%</td>
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assaying surface expression of chemosensory receptors in heterologous cells

El vívido mundo de los olores es reconocido por el sentido del olfato. El olfato de los ratones es mediada por un repertorio de alrededor de 1.200 receptores acoplados a proteínas G (GPCR) 1 que se postulan para unirse las moléculas volátiles de olor y la conversión de la señal extracelular en una señal intracelular mediante el acoplamiento con la proteína G Gαolf. La unión de los olores de los receptores se cree que siguen una regla combinatoria, es decir, un olor puede obligar a varios receptores y un receptor puede unirse olores varios en distintos grados 2. Señalización bioquímica, y ligando los estudios de unión han sido convenientemente llevado a cabo para la mayoría de los GPCRs utilizando células heterólogas. Sin embargo el uso de células heterólogas para el estudio de los receptores de olor, fue excluida por mucho tiempo ya que en la transfección no pudieron exportar a la superficie. Saito et al han demostrado receptores de membrana de una sola pasada de Transporte de proteínas (RTP) acompañantes de la familia muestran una mayor expresión en las neuronas olfativas sensoriales y actuar como acompañantes a los receptores de olor de tráfico a la superficie en células heterólogas, cuando co transfectadas juntos 3. Para llevar a cabo los análisis bioquímicos de los receptores con células heterólogas, primero hay que determinar si el receptor muestra la expresión de superficie sólida en la línea celular. Esto se puede probar por sobreexpresión de los receptores con el RTP1S acompañante seguido por tinción de células vivas para la etiqueta fluorescente el dominio extracelular o una etiqueta en el dominio extracelular de forma exclusiva. Aquí se demuestra un protocolo para llevar a cabo la tinción de células vivas que se pueden utilizar para detectar los receptores de olor en la superficie de las células HEK293T convenientemente. Además, también puede ser utilizado para el ensayo de expresión en la superficie de otros receptores o quimiosensoriales GPCRs.

Watch this Scientific Journal Video about Assaying Surface Expression of Chemosensory Receptors in Heterologous Cells at JoVE.com

Assaying Surface Expression of Chemosensory Receptors in Heterologous Cells

Aquí se demuestra un protocolo para llevar a cabo la tinción de células vivas que se pueden utilizar para detectar los receptores de olor en la superficie de las células HEK293T convenientemente. Además, también puede ser utilizado para el ensayo de expresión en la superficie de otros receptores o quimiosensoriales GPCRs.

Analizando la expresión de superficie de los receptores Quimiosensoriales en células heterólogas

The vivid world of odors is recognized by the sense of olfaction. Olfaction in mice is mediated by a repertoire of about 1200 G Protein Coupled Receptors ...

assaying-surface-expression-chemosensory-receptors-heterologous

Research

JoVE Journal

Neuroscience

10.8K vistas.  Duke University. Aquí se demuestra un protocolo para llevar a cabo la tinción de células vivas que se pueden utilizar para detectar los receptores de olor en la superficie de las células HEK293T convenientemente. Además, también puede ser utilizado para el ensayo de expresión en la superficie de otros receptores o quimiosensoriales GPCRs.

Video: Assaying Surface Expression of Chemosensory Receptors in Heterologous Cells

Assaying Locomotor Activity to Study Circadian Rhythms and Sleep Parameters in Drosophila

Most life forms exhibit daily rhythms in cellular, physiological and behavioral phenomena that are driven by endogenous circadian (&equiv;24 hr) pacemakers or clocks. Malfunctions in the human circadian system are associated with numerous diseases or disorders. Much progress towards our understanding of the mechanisms underlying circadian rhythms has emerged from genetic screens whereby an easily measured behavioral rhythm is used as a read-out of clock function. Studies using Drosophila have made seminal contributions to our understanding of the cellular and biochemical bases underlying circadian rhythms. The standard circadian behavioral read-out measured in Drosophila is locomotor activity. In general, the monitoring system involves specially designed devices that can measure the locomotor movement of Drosophila. These devices are housed in environmentally controlled incubators located in a darkroom and are based on using the interruption of a beam of infrared light to record the locomotor activity of individual flies contained inside small tubes. When measured over many days, Drosophila exhibit daily cycles of activity and inactivity, a behavioral rhythm that is governed by the animal's endogenous circadian system. The overall procedure has been simplified with the advent of commercially available locomotor activity monitoring devices and the development of software programs for data analysis. We use the system from Trikinetics Inc., which is the procedure described here and is currently the most popular system used worldwide. More recently, the same monitoring devices have been used to study sleep behavior in Drosophila. Because the daily wake-sleep cycles of many flies can be measured simultaneously and only 1 to 2 weeks worth of continuous locomotor activity data is usually sufficient, this system is ideal for large-scale screens to identify Drosophila manifesting altered circadian or sleep properties.

Assaying Locomotor Activity to Study Circadian Rhythms and Sleep Parameters in Drosophila

We describe procedures for recording daily locomotor activity rhythms of Drosophila and subsequent data analysis. Locomotor activity rhythms are a reliable behavioral output of animal circadian clocks and are used as the standard readout of clock function when studying circadian mutants or examining how the environment regulates the circadian system.

Ensayo Actividad locomotora para el Estudio de los ritmos circadianos y del sueño en los parámetros Drosophila</em

Most life forms exhibit daily rhythms in cellular, physiological and behavioral phenomena that are driven by endogenous circadian (&equiv;24 hr) ...

Investigación

Neurociencias

Assaying Locomotor, Learning, and Memory Deficits in Drosophila Models of Neurodegeneration

Advances in genetic methods have enabled the study of genes involved in human neurodegenerative diseases using Drosophila as a model system1. Most of these diseases, including Alzheimer's, Parkinson's and Huntington's disease are characterized by age-dependent deterioration in learning and memory functions and movement coordination2. Here we use behavioral assays, including the negative geotaxis assay3 and the aversive phototaxic suppression assay (APS assay)4,5, to show that some of the behavior characteristics associated with human neurodegeneration can be recapitulated in flies. In the negative geotaxis assay, the natural tendency of flies to move against gravity when agitated is utilized to study genes or conditions that may hinder locomotor capacities. In the APS assay, the learning and memory functions are tested in positively-phototactic flies trained to associate light with aversive bitter taste and hence avoid this otherwise natural tendency to move toward light. Testing these trained flies 6 hours post-training is used to assess memory functions. Using these assays, the contribution of any genetic or environmental factors toward developing neurodegeneration can be easily studied in flies.

Assaying Locomotor, Learning, and Memory Deficits in Drosophila Models of Neurodegeneration

Behavior assays for measuring locomotor functions, learning, and memory abilities in Drosophila.

Locomotor ensayo, aprendizaje, memoria y déficit en Drosophila Los modelos de neurodegeneración

Advances in genetic methods have enabled the study of genes involved in human neurodegenerative diseases using Drosophila as a model system1. Most of ...

Spinal Cord Electrophysiology II: Extracellular Suction Electrode Fabrication

Development of neural circuitries and locomotion can be studied using neonatal rodent spinal cord central pattern generator (CPG) behavior. We demonstrate a method to fabricate suction electrodes that are used to examine CPG activity, or fictive locomotion, in dissected rodent spinal cords. The rodent spinal cords are placed in artificial cerebrospinal fluid and the ventral roots are drawn into the suction electrode. The electrode is constructed by modifying a commercially available suction electrode. A heavier silver wire is used instead of the standard wire given by the commercially available electrode. The glass tip on the commercial electrode is replaced with a plastic tip for increased durability. We prepare hand drawn electrodes and electrodes made from specific sizes of tubing, allowing consistency and reproducibility. Data is collected using an amplifier and neurogram acquisition software. Recordings are performed on an air table within a Faraday cage to prevent mechanical and electrical interference, respectively.

A demonstration of the fabrication and use of an extracellular suction electrode used to measure electrophysiological recordings of neonatal rodent spinal cords in vitro

Médula Espinal Electrofisiología II: Fabricación de electrodos de aspiración extracelular

Development of neural circuitries and locomotion can be studied using neonatal rodent spinal cord central pattern generator (CPG) behavior. We demonstrate ...

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 ...

Isolating Nasal Olfactory Stem Cells from Rodents or Humans

The olfactory mucosa, located in the nasal cavity, is in charge of detecting odours. It is also the only nervous tissue that is exposed to the external environment and easily accessible in every living individual. As a result, this tissue is unique for anyone aiming to identify molecular anomalies in the pathological brain or isolate adult stem cells for cell therapy. 
Molecular abnormalities in brain diseases are often studied using nervous tissue samples collected post-mortem. However, this material has numerous limitations. In contrast, the olfactory mucosa is readily accessible and can be biopsied safely without any loss of sense of smell1. Accordingly, the olfactory mucosa provides an "open window" in the adult human through which one can study developmental (e.g. autism, schizophrenia)2-4 or neurodegenerative (e.g. Parkinson, Alzheimer) diseases4,5. Olfactory mucosa can be used for either comparative molecular studies4,6 or in vitro experiments on neurogenesis3,7.
The olfactory epithelium is also a nervous tissue that produces new neurons every day to replace those that are damaged by pollution, bacterial of viral infections. This permanent neurogenesis is sustained by progenitors but also stem cells residing within both compartments of the mucosa, namely the neuroepithelium and the underlying lamina propria8-10. We recently developed a method to purify the adult stem cells located in the lamina propria and, after having demonstrated that they are closely related to bone marrow mesenchymal stem cells (BM-MSC), we named them olfactory ecto-mesenchymal stem cells (OE-MSC)11.
Interestingly, when compared to BM-MSCs, OE-MSCs display a high proliferation rate, an elevated clonogenicity and an inclination to differentiate into neural cells. We took advantage of these characteristics to perform studies dedicated to unveil new candidate genes in schizophrenia and Parkinson's disease4. We and others have also shown that OE-MSCs are promising candidates for cell therapy, after a spinal cord trauma12,13, a cochlear damage14 or in an animal models of Parkinson's disease15 or amnesia16.
In this study, we present methods to biopsy olfactory mucosa in rats and humans. After collection, the lamina propria is enzymatically separated from the epithelium and stem cells are purified using an enzymatic or a non-enzymatic method. Purified olfactory stem cells can then be either grown in large numbers and banked in liquid nitrogen or induced to form spheres or differentiated into neural cells. These stem cells can also be used for comparative omics (genomic, transcriptomic, epigenomic, proteomic) studies.

We describe here a method for biopsying olfactory mucosa from rat and human nasal cavities. These biopsies can be used for either identifying molecular anomalies in brain diseases or isolating multipotent adult stem cells that can be utilized for cell transplantation in animal models of brain trauma/disease.

Aislar las células madre olfativo nasal de los roedores o los seres humanos

The olfactory mucosa, located in the nasal cavity, is in charge of detecting odours. It is also the only nervous tissue that is exposed to the external ...

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 ...

Assaying DNA Damage in Hippocampal Neurons Using the Comet Assay

A number of drugs target the DNA repair pathways and induce cell kill by creating DNA damage. Thus, processes to directly measure DNA damage have been extensively evaluated. Traditional methods are time consuming, expensive, resource intensive and require replicating cells. In contrast, the comet assay, a single cell gel electrophoresis assay, is a faster, non-invasive, inexpensive, direct and sensitive measure of DNA damage and repair. All forms of DNA damage as well as DNA repair can be visualized at the single cell level using this powerful technique.
	The principle underlying the comet assay is that intact DNA is highly ordered whereas DNA damage disrupts this organization. The damaged DNA seeps into the agarose matrix and when subjected to an electric field, the negatively charged DNA migrates towards the cathode which is positively charged. The large undamaged DNA strands are not able to migrate far from the nucleus. DNA damage creates smaller DNA fragments which travel farther than the intact DNA. Comet Assay, an image analysis software, measures and compares the overall fluorescent intensity of the DNA in the nucleus with DNA that has migrated out of the nucleus. Fluorescent signal from the migrated DNA is proportional to DNA damage. Longer brighter DNA tail signifies increased DNA damage. Some of the parameters that are measured are tail moment which is a measure of both the amount of DNA and distribution of DNA in the tail, tail length and percentage of DNA in the tail. This assay allows to measure DNA repair as well since resolution of DNA damage signifies repair has taken place. The limit of sensitivity is approximately 50 strand breaks per diploid mammalian cell 1,2. Cells treated with any DNA damaging agents, such as etoposide, may be used as a positive control. Thus the comet assay is a quick and effective procedure to measure DNA damage.

The comet assay is an efficient way of detecting single- and double-strand breaks, including alkali-labile sites and DNA-DNA/DNA-protein cross-links on the DNA in all cells including hippocampal neurons. The method takes advantage of the differential migration of DNA in an electric field due to differences in amount of DNA damage.

Ensayo de daño del ADN en las neuronas del hipocampo utilizando el ensayo cometa

A number of drugs target the DNA repair pathways and induce cell kill by creating DNA damage. Thus, processes to directly measure DNA damage have been ...

Proprioception and Tension Receptors in Crab Limbs: Student Laboratory Exercises

The primary purpose of these procedures is to demonstrate for teaching and research purposes how to record the activity of living primary sensory neurons responsible for proprioception as they are detecting joint position and movement, and muscle tension. Electrical activity from crustacean proprioceptors and tension receptors is recorded by basic neurophysiological instrumentation, and a transducer is used to simultaneously measure force that is generated by stimulating a motor nerve. In addition, we demonstrate how to stain the neurons for a quick assessment of their anatomical arrangement or for permanent fixation. Staining reveals anatomical organization that is representative of chordotonal organs in most crustaceans. Comparing the tension nerve responses to the proprioceptive responses is an effective teaching tool in determining how these sensory neurons are defined functionally and how the anatomy is correlated to the function. Three staining techniques are presented allowing researchers and instructors to choose a method that is ideal for their laboratory.

Physiological and anatomical techniques are demonstrated to address function and structure for joint proprioceptors and muscle tension receptors in crustacean walking limbs.

Propiocepción y la tensión en los receptores de cangrejo Limbs: Ejercicios de Laboratorio Estudiante

The primary purpose of these procedures is to demonstrate for teaching and research purposes how to record the activity of living primary sensory neurons ...

Inducing Plasticity of Astrocytic Receptors by Manipulation of Neuronal Firing Rates

Close to two decades of research has established that astrocytes in situ and in vivo express numerous G protein-coupled receptors (GPCRs) that can be stimulated by neuronally-released transmitter. However, the ability of astrocytic receptors to exhibit plasticity in response to changes in neuronal activity has received little attention. Here we describe a model system that can be used to globally scale up or down astrocytic group I metabotropic glutamate receptors (mGluRs) in acute brain slices. Included are methods on how to prepare parasagittal hippocampal slices, construct chambers suitable for long-term slice incubation, bidirectionally manipulate neuronal action potential frequency, load astrocytes and astrocyte processes with fluorescent Ca2+ indicator, and measure changes in astrocytic Gq GPCR activity by recording spontaneous and evoked astrocyte Ca2+ events using confocal microscopy. In essence, a &#8220;calcium roadmap&#8221; is provided for how to measure plasticity of astrocytic Gq GPCRs. Applications of the technique for study of astrocytes are discussed. Having an understanding of how astrocytic receptor signaling is affected by changes in neuronal activity has important implications for both normal synaptic function as well as processes underlying neurological disorders and neurodegenerative disease.

Here we describe an adaptation of protocols used to induce homeostatic plasticity in neurons for the study of plasticity of astrocytic G protein-coupled receptors. Recently used to examine changes in astrocytic group I mGluRs in juvenile mice, the method can be applied to measure scaling of various astrocytic GPCRs, in tissue from adult mice in situ and in vivo, and to gain a better appreciation of the sensitivity of astrocytic receptors to changes in neuronal activity.

La inducción de la plasticidad de astrocítico Receptores por manipulación de Neuronales cocción Precios

Close to two decades of research has established that astrocytes in situ and in vivo express numerous G protein-coupled receptors (GPCRs) that can be ...

Determining Cell-surface Expression and Endocytic Rate of Proteins in Primary Astrocyte Cultures Using Biotinylation

Cell-surface proteins mediate a wide array of functions. In many cases, their activity is regulated by endocytic processes that modulate their levels at the plasma membrane. Here, we present detailed protocols for 2 methods that facilitate the study of such processes, both of which are based on the principle of the biotinylation of cell-surface proteins. The first is designed to allow for the semi-quantitative determination of the relative levels of a particular protein at the cell-surface. In it, the lysine residues of the plasma membrane proteins of cells are first labeled with a biotin moiety. Once the cells are lysed, these proteins may then be specifically precipitated via the use of agarose-immobilized streptavidin by exploiting the natural affinity of the latter for biotin. The proteins isolated in such a manner may then be analyzed via a standard western blotting approach. The second method provides a means of determining the endocytic rate of a particular cell-surface target over a period of time. Cell-surface proteins are first modified with a biotin derivative containing a cleavable disulfide bond. The cells are then shifted back to normal culture conditions, which causes the endocytic uptake of a proportion of biotinylated proteins. Next, the disulfide bonds of non-internalized biotin groups are reduced using the membrane-impermeable reducing agent glutathione. Via this approach, endocytosed proteins may thus be isolated and quantified with a high degree of specificity.

Two biotinylation-based methods, designed for determining the cell-surface expression and endocytic rate of proteins expressed at the plasma membrane, are presented in this report.

Determinación de la expresión de la superficie celular y la tasa endocítica de proteínas en cultivos de astrocitos primarios usando biotinilación

Cell-surface proteins mediate a wide array of functions. In many cases, their activity is regulated by endocytic processes that modulate their levels at ...