Nous remercions les membres du laboratoire pour Matsunami lecture critique de ce manuscrit.

1. Procédure: La procédure comprend trois parties réalisé sur une durée totale de 3 jours: les cellules de transfert, la transfection et l&#39;immunocytochimie, une étape menée par jour. Transfert et transfection de cellules au cours des deux premiers jours doit être effectué dans des conditions stériles dans une chambre à flux laminaire. Jour 1: Transfert de cellules pour le dosage HEK293T expression à la surface. <ol><li> Le fluide caloporteur (M10): Mélanger milieu essentiel minimum supplémenté avec 10% (en volume) de sérum bovin fœtal à l&#39;état stérile. </li><li> Cultiver des cellules à une confluence souhaité dans une plaque de culture de 100 mm, selon le nombre de plaques nécessaires pour mettre en place. Il est important de déterminer la fraction de cellules pour être transféré à éviter des cellules envahies ou clairsemés: par exemple, à partir d&#39;un 100% de confluence 100 mm plat, on peut transférer environ 3% à un plat de 35 mm afin d&#39;obtenir environ 30% de confluence dans le celui-ci. </li><li> Avant le transfert de cellules, dans la chambre de flux laminaire stérile, manteau 22 X 22 mm en verre glisse couvrir avec la lysine stériles poly D (1 mg / ml) et placer un dans chaque plat de 35 mm de culture cellulaire, face enduite pour plaquage cellules (figure 1 ). Laisser la solution à sec pendant 5 - 10 minutes. Durant cet intervalle, la source UV dans la chambre de laminaire peut être activée pour stériliser les lamelles, si désiré. Poly D lysine aide les cellules hétérologues coller à l&#39;lamelles. </li><li> Pour transférer des cellules, aspirer à des médias existants dans le plat 100mm, se laver en prenant soin d&#39;ajouter 8 ml de PBS stérile, aspirer PBS et les cellules en utilisant trypsiniser 3 mL 0,05% de trypsine-EDTA; lorsque les cellules se détachent de la vaisselle, bloc de réaction enzymatique par d&#39;autres ajoutant 5 ml M10. Triturer les cellules et le transfert du volume requis pour un tube stérile conique; centrifuger à 200g pendant 5 minutes pour sédimenter les cellules. Aspirer à surnageant contenant la trypsine-EDTA, laissant le culot de cellules intactes. Pour transférer les cellules à plaques de 35 mm, ajouter 1 ml M10 pour chaque plat et triturer à dissocier les cellules. Ajouter 1 mL de cellules en suspension à chaque plat. Incuber les cellules pendant la nuit à 37 ° C, 5% de CO 2. <img src="/files/ftp_upload/2405/2405fig1.jpg" alt="Figure 1" /> Figure 1. Coat 22 X 22 mm avec des lamelles en verre poly D lysine et le lieu couché une face dans chaque plat de 35 mm. </li></ol> Jour 2: La transfection de cellules HEK293T. <ol><li> 18-24 heures après le transfert, les cellules sont prêtes pour la transfection du récepteur à doser. Utilisez des récepteurs et RTP1S clonés dans le vecteur d&#39;expression mammifère PCI, préparés à partir de cultures bactériennes en utilisant Qiagen Miniprep Kit protocole suivant décrit avant 4. Utilisez des récepteurs qui sont N terminale taggés avec 20 acides aminés à long épitope rhodopsine pour faciliter immunomarquage. </li><li> Utilisez des 1000ng construire des récepteurs, 250 ng de RTP1S construire et 50 ng de protéine à fluorescence verte chaque transfection. Effectuer transfection en utilisant Lipofectamine 2000, conformément au manuel du fabricant. </li></ol> Jour 3: immunocytochimie de visualiser les récepteurs de surface des cellules colorées. <ol><li> Avant de commencer, préparer la coloration et des solutions de lavage et de les refroidir à 4 ° C. Coloration moyennes: Minimum Essential Medium, 45 ml; sérum de veau fœtal, 5 ml; HEPES (1M), 500 ul (concentration finale 10 mM); azide de sodium (1,5 M), 500 ul (concentration finale 15 mM). Solution de lavage: HBSS, 500 ml; HEPES (1M), 5 ml (concentration finale 10 mM); azide de sodium (1,5 M), 5 ml (concentration finale 15 mM). Les deux solutions peuvent être conservés à 4 ° C pour les réutiliser. Préparer des solutions d&#39;anticorps en diluant les anticorps nécessaires à moyen et coloration 100 fois. </li><li> Démarrer immunochimie pour la coloration de surface pour les récepteurs olfactifs environ 24 heures après la transfection. Pour effectuer une coloration de cellules vivantes, le dispositif expérimental suivi doit être refroidi à 4 ° C: remplissez un grand contenu de glace et de Pat la surface de la glace pour la rendre aussi uniforme que possible, placez un bac sur la glace et de le vaporiser avec 70% l&#39;éthanol. Coupez un morceau de parafilm (plus petit que la longueur du bac) et l&#39;apposer sur le plateau de l&#39;éthanol pulvérisé, pour obtenir une surface lisse. Transférer les lamelles de verre contenant des cellules transfectées sur le parafilm, un à la fois, côté pile, en utilisant une pince à épiler. Couche de chaque lamelle avec 100 uL solution de coloration à froid primaire, extrusion soin à partir d&#39;un coin de la glisse (figure 2). Après superposition de tous les bordereaux de couvrir avec une solution d&#39;anticorps, couvrir le bac pour éviter l&#39;assèchement de la solution dans l&#39;air. Effectuer une incubation primaires pendant 45-60 minutes. </li><li> Après une incubation de primaire, de transférer rapidement des lamelles de la culture de plats originaux 35mm, contenant les médias. Aspirer les médias et ajouter 2 ml de solution de lavage refroidie doucement à partir du bord du plat pour éviter de perdre les cellules de la lamelle. Aspirer la solution de lavage et de répéter deux fois pour terminer trois lavages. A la fin du troisième lavage, ne pas aspirer la solution au lavage. </li><li> Préparer anticorps secondaire solutidans les médias coloration et de transférer les lamelles de la solution de lavage à une couche de parafilm nouvellement apposée dans le même bac. Encore une fois délicatement extruder 100 uL de solution d&#39;anticorps à la couche de chaque lamelle, à partir du coin, comme l&#39;incubation primaire. Effectuer une incubation secondaire pour 30 - 45 minutes et transfert à la solution de lavage dans les 35 plats originaux mm. Une fois de plus, se laver le couvercle glisse trois fois comme décrit. </li><li> Aspirer la solution de lavage du dernier lavage et ajouter 2 ml de paraformaldéhyde 1% réfrigérée. Fixer les cellules dans une solution de paraformaldéhyde réfrigérée à 1%, sur la glace pendant 15 minutes. </li><li> Montez le couvercle glisse sur le verre de microscope propre diapositives à l&#39;aide de réactifs de montage Mowiol, avec le côté pile vers le bas et prudemment exclure toutes les bulles d&#39;air (figure 3). Une fois séché à l&#39;air Mowiol, lavez délicatement lamelles en ajoutant de l&#39;eau distillée sur la surface et aspirer immédiatement. <img src="/files/ftp_upload/2405/2405fig2.jpg" alt="Figure 2" /> Figure 2. Couche de chaque lamelle avec 100 uL solution de coloration à froid primaire. <img src="/files/ftp_upload/2405/2405fig3.jpg" alt="Figure 3" /> Figure 3. Monter les lamelles avec le côté pile vers le bas sur microscope en verre propres diapositives à l&#39;aide de réactifs Mowiol montage. </li></ol> 2. Les résultats représentatifs: Coloration des cellules en direct permet de visualiser les protéines à la surface des cellules, sur la transfection de récepteurs avec des chaperons (dans ce cas, des récepteurs olfactifs Olfr62, avec RTP1S récepteur protéique Transport) (figure 4). Coloration de la surface cellulaire des récepteurs est caractérisée par le modèle ponctuée de taches (figure 4B, en médaillon). Coloration effectué de façon inappropriée peut entraîner une augmentation du bruit, ce qui rend difficile pour l&#39;observateur de distinguer la coloration de surface réelle du bruit. <img src="/files/ftp_upload/2405/2405fig4.jpg" alt="Figure 4" /> Transfection Figure 4. Des récepteurs avec des chaperons permet la visualisation des protéines à la surface des cellules utilisant une coloration de cellules vivantes. La transfection du récepteur odorant Olfr62 seul (A) et la transfection de Olfr62 avec chaperon RTP1S (B). Les niveaux d&#39;expression de GFP servir de contrôle de transfection (A &#39;et 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>

Chaque étape doit être réalisée avec soin pour s&#39;assurer coloration de surface importante et distinctive. Le processus de coloration au complet doit être effectué à froid (sur glace), et le plateau sur lequel sont fixées des lamelles doit être refroidi avant de l&#39;utiliser pour assurer les cellules rester en vie. Par ailleurs la fixation est effectuée à la fin du processus de coloration de surface. Ceci est en contraste frappant avec la coloration interne où la fixation précède coloration pour perm?...

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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>
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<td>Paraformaldehyde</td>
<td>&nbsp;</td>
<td>EMS</td>
<td>19208</td>
<td>&nbsp;</td>
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<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>
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<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>
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<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

Le monde des odeurs vives est reconnu par le sens de l&#39;olfaction. Olfaction chez la souris est médiée par un répertoire d&#39;environ 1200 récepteurs couplés aux protéines G (RCPG) 1 qui sont postulés pour lier les molécules odorantes volatiles et en convertissant le signal extracellulaire en signal intracellulaire par couplage avec la protéine G Gαolf. La liaison de l&#39;odorants aux récepteurs est pensé pour suivre une règle combinatoire, qui est, un odorant peut lier plusieurs récepteurs et un récepteur peut se lier plusieurs molécules odorantes à des degrés divers 2. Biochimiques, la signalisation et des études de liaison ligand ont été commodément effectuée pour la plupart des RCPG en utilisant des cellules hétérologues. Cependant l&#39;utilisation de cellules hétérologues pour l&#39;étude des récepteurs olfactifs, a été exclue pour un temps depuis longtemps sur la transfection ils ont échoué à l&#39;exportation vers la surface. Saito et al ont démontré seule récepteur membranaire passent protéine de transport (RTP) chaperons familiales montrent une expression accrue dans les neurones olfactifs sensoriels et d&#39;agir comme accompagnateur à récepteurs olfactifs du trafic à la surface des cellules hétérologues, en cas de co transfectées ensemble 3. Pour mener à bien des dosages biochimiques des récepteurs utilisant des cellules hétérologues, on doit d&#39;abord déterminer si le récepteur affiche l&#39;expression en surface robuste dans la lignée cellulaire. Cela peut être dosé en surexprimant les récepteurs à la RTP1S chaperon suivie par coloration de cellules vivantes à fluorescence étiquette du domaine extracellulaire ou un tag dans le domaine extracellulaire exclusivement. Ici nous démontrons un protocole pour mener à bien coloration de cellules vivantes qui peuvent être utilisés pour détecter les récepteurs olfactifs à la surface des cellules HEK293T commodément. En outre, il peut également être utilisé pour le dosage de l&#39;expression de surface d&#39;autres récepteurs chimiosensoriels ou RCPG.

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

Ici nous démontrons un protocole pour mener à bien coloration de cellules vivantes qui peuvent être utilisés pour détecter les récepteurs olfactifs à la surface des cellules HEK293T commodément. En outre, il peut également être utilisé pour le dosage de l&#39;expression de surface d&#39;autres récepteurs chimiosensoriels ou RCPG.

Dosage expression en surface des récepteurs chimiosensoriels dans des cellules hétérologues

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

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Neuroscience

10.8K vues.  Duke University. Ici nous démontrons un protocole pour mener à bien coloration de cellules vivantes qui peuvent être utilisés pour détecter les récepteurs olfactifs à la surface des cellules HEK293T commodément. En outre, il peut également être utilisé pour le dosage de l'expression de surface d'autres récepteurs chimiosensoriels ou RCPG.

Vidéo: 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.

Dosage activité locomotrice d&#39;étudier les rythmes circadiens et le sommeil dans les paramètres Drosophile</em

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

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Neurosciences

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.

Déficits locomoteur Dosage, apprentissage et mémoire dans Drosophile Modèles de la neurodégénérescence

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

La moelle épinière électrophysiologie II: fabrication des électrodes extracellulaires d&#39;aspiration

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

Imagerie des cellules vivantes des cellules sensorielles de précurseurs d&#39;organes en Intact Drosophile Les chrysalides

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.

Isoler les cellules souches nasal olfactif des rongeurs ou des êtres humains

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.

Imagerie à haute résolution en direct du comportement des cellules dans le développement neuro-épithélium

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.

Le dosage de dommages de l&#39;ADN dans les neurones hippocampiques Utilisation de l&#39;essai de comète

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.

Proprioception et tension récepteurs en crabe Membres: Exercices de laboratoire étudiant

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.

Induire la plasticité de Astrocytic récepteurs neuronaux par manipulation des taux de combustion

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.

Détermination de l&#39;expression de la surface cellulaire et du taux endocytique des protéines dans les cultures d&#39;astritcy primaires utilisant la 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 ...