Ce travail a été soutenu par une subvention de la DFG avec l&#39;heure GMT

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M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+dynamics+of+axon+pathfinding+in+the+Drosophilia+CNS:+a+time-lapse+study+of+an+identified+motorneuron.">In vivo dynamics of axon pathfinding in the Drosophilia CNS: a time-lapse study of an identified motorneuron.</a> J. Neurobiol. 37, 607-621 (1998).</li><li>Patel, N. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+neuronal+subsets+and+other+cell+types+in+whole-mount+Drosophila+embryos+and+larvae+using+antibody+probes.">Imaging neuronal subsets and other cell types in whole-mount Drosophila embryos and larvae using antibody probes.</a> Methods Cell Biol. 44, 445-487 (1994).</li><li>Rickert, C., Kunz, T., Harris, K. -. L., Whitington, P. M., Technau, G. 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S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=From+grasshopper+to+Drosophila:+a+common+plan+for+neuronal+development.">From grasshopper to Drosophila: a common plan for neuronal development.</a> Nature. 310, 203-207 (1984).</li><li>Whitington, P., Harris, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+axonogenesis+in+the+embryo+of+a+primitive+insect,+the+silverfish+Ctenolepisma+longicaudata.">Early axonogenesis in the embryo of a primitive insect, the silverfish Ctenolepisma longicaudata.</a> Development Genes and Evolution. 205 (5-6), 272-281 (1996).</li><li>Whitington, P., Meier, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Segmentation,+neurogenesis+and+formation+of+early+axonal+pathways+in+the+centipede,+Ethmostigmus+rubripes+(Brandt).">Segmentation, neurogenesis and formation of early axonal pathways in the centipede, Ethmostigmus rubripes (Brandt).</a> Development Genes and Evolution. 199, 349-363 (1991).</li><li>Whitington, P. M., Seifert, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Axon+growth+from+limb+motorneurons+in+the+locust+embryo:+the+effect+of+target+limb+removal+on+the+pattern+of+axon+branching+in+the+periphery.">Axon growth from limb motorneurons in the locust embryo: the effect of target limb removal on the pattern of axon branching in the periphery.</a> Developmental Biology. 106, 438-449 (1984).</li><li>Whitington, P. M., Leach, D., Sandeman, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evolutionary+change+in+neural+development+within+the+arthropods:+axonogenesis+in+the+embryos+of+two+crustaceans.">Evolutionary change in neural development within the arthropods: axonogenesis in the embryos of two crustaceans.</a> Development. 118, 449-461 (1993).</li><li>Williams, D. W., Tyrer, M., Shepherd, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tau+and+tau+reporters+disrupt+central+projections+of+sensory+neurons+in+Drosophila.">Tau and tau reporters disrupt central projections of sensory neurons in Drosophila.</a> J. Comp. Neurol. 428, 630-640 (2000).</li></ol>

Les auteurs déclarent n&#39;avoir aucun conflit d&#39;intérêts financiers.

Un avantage majeur de la drosophile comme modèle de système est qu&#39;il permet l&#39;analyse du développement et de la fonction au niveau des cellules individuelles. Ceci est particulièrement utile en ce qui concerne le système nerveux, où la diversité des types de cellules est exceptionnellement élevé et la fonction et la morphologie des cellules voisines peut être totalement différente. Procédé nous présentons ici permet le marquage des neurones individuels avec un...

La connaissance de la morphologie neuronale au niveau des cellules individuelles est une condition essentielle pour la compréhension de la connectivité neuronale et la fonction du système nerveux central. Ainsi, dès les premiers jours de la neuroscience, les chercheurs ont cherché à développer des simples techniques de marquage de cellules (voir 7 pour un traitement historique de cette question). Les méthodes classiques comme la coloration de Golgi fournir une excellente résolution de la morphologie neuronale, mais ne sont pas adaptés si l&#39;on cherche à identifier un type particulier de neurone d&#39;une manière dirigée, que la coloration se produit de façon aléatoire. Le développement de méthodes pour la coloration des cellules individuelles par injection intracellulaire ou juxtacellulaire de colorants à partir d&#39;une microélectrode l&#39;exigence en matière d&#39;étiquetage spécifique. L&#39;application de neurone unique colorant injection chez la drosophile a présenté un défi majeur, en raison de la petite taille de l&#39;organisme et à la fois ses neurones. Néanmoins, la coloration seul neurone de Drosophila embryonnaire </em&gt; Neurones a été atteint au milieu des années 1980 dans le laboratoire de Corey Goodman 15. Bien que la méthode a été éminemment utile et a fourni des renseignements clés sur les mécanismes de développement neuronal chez la drosophile au cours des 20-30 dernières années (par exemple, 2, 10), de nombreux travailleurs ont renoncé en grande partie à cause de ses exigences techniques. La disponibilité de ces dernières années des techniques génétiques pour l&#39;étiquetage des neurones chez la drosophile a également contribué à l&#39;impopularité de l&#39;injection de colorant unique neurone. Expression GAL4-dirigé des constructions GFP membrane ciblées peuvent fournir une excellente résolution de la morphologie des neurones 1, 20. Cependant, cette méthode présente certaines limites: l&#39;expression souvent inévitable de la GFP dans les cellules multiples peuvent obscurcir la structure des neurones individuels et une ligne pilote de GAL4 peut ne pas être disponible pour conduire l&#39;expression dans un neurone d&#39;intérêt particulier. Le MarcM (Analyse mosaïque avec un représentantmarqueur des cellules ressible) Méthode 8 peut fournir l&#39;étiquetage des neurones essentiellement tout au niveau de la cellule individuelle, mais ne peut pas être utilisé avec succès dans l&#39;embryon et la larve au début à cause de la rotation lente de la protéine GAL80. Compte tenu de ces limites de l&#39;étiquetage génétique, nous croyons que l&#39;injection de colorant seul neurone dans l&#39;embryon de drosophile reste une technique intéressante et mérite une plus large application. Pour promouvoir cet objectif, nous proposons ici une description détaillée de la méthode. Une illustration de sa puissance est fournie par notre récent compte de la morphologie de l&#39;ensemble des interneurones dans neuromeres abdominale de l&#39;embryon chez la drosophile fin 14. Cette étude, qui révèle à la fois la variabilité morphologique des différents types de cellules neuronales et les principes d&#39;organisation neuromere dans le SNC de l&#39;embryon, n&#39;aurait pas été possible avec n&#39;importe quelle méthode d&#39;étiquetage actuellement disponible autres.

<table border="1"><tbody><tr><td> Nom de réactif / Matériel </td><td> Entreprise </td><td> Numéro de catalogue </td><td> Commentaires </td></tr><tr><td></td><td></td><td></td><td> REACTIFS </td></tr><tr><td> DAB </td><td> Sigma-Aldrich </td><td> <a href="http://www.sigmaaldrich.com/catalog/product/sigma/d5905" target="_blank">D-5905</a> </td><td> 2-3 mg / ml dans 100 mM Tris-HCl, pH 7,4 </td></tr><tr><td> Dil </td><td> Sondes Invitrogen / moléculaires </td><td> <a href="http://products.invitrogen.com/ivgn/product/D282" target="_blank">D-282</a> </td><td> 1 mg / ml dans de l&#39;éthanol </td></tr><tr><td> <a href="http://www.merckmillipore.com/germany/chemicals/formaldehydloesung-min-37-prozent/MDA_CHEM-104002/p_Wt6b.s1L6pAAAAEWpOEfVhTl" target="_blank">Formaldéhyde</a> </td><td> Merck Millipore </td><td></td><td> 7,4% dans du PBS </td> &lt;/ Tr&gt; <tr><td> Glycérol </td><td> <a href="http://www.carlroth.com/catalogue/" target="_blank">Roth</a> </td><td> 3783 </td><td> 70% dans du PBS </td></tr><tr><td> Heptane colle </td><td> Beiersdorf AG </td><td> Violoncelle 31-39-30 * </td><td> diluer env. 1 à 1 avec du n-heptane </td></tr><tr><td> PBS </td><td></td><td></td><td> 1x </td></tr><tr><td> TRIS </td><td> <a href="http://www.carlroth.com/catalogue/" target="_blank">Roth</a> </td><td> 4855 </td><td></td></tr><tr><td> Vectashield </td><td> Vector Laboratories </td><td> <a href="http://www.vectorlabs.com/catalog.aspx?prodID=427" target="_blank">H1000</a> </td><td></td></tr><tr><td></td><td></td><td></td><td> ÉQUIPEMENT </td></tr><tr><td> Microscope confocal </td><td> Leica </td><td> TCS SP2 </td><td> de visualiser et de documenter les marquages ​​en fluorescence </td></tr><tr><td> DC - unemplifier </td><td> Dragan Corporation </td><td> Cornerstone ION-100 </td><td> pour effectuer les marquages </td></tr><tr><td> Lamelles de </td><td> <a href="http://www.menzel.de/" target="_blank">Menzel</a> </td><td> BB018018A1 </td><td> 18 x 18 mm </td></tr><tr><td> Lamelles de </td><td> <a href="http://www.menzel.de/" target="_blank">Menzel</a> </td><td> BB024060A1 </td><td> 24 x 60 mm </td></tr><tr><td> Microscope à dissection </td><td> Leica </td><td> MZ8 </td><td> de préparer et de disect embryons </td></tr><tr><td> Plat capillaires </td><td> <a href="http://www.hilgenberg-gmbh.de/" target="_blank">Hilgenberg</a> </td><td></td><td> le diamètre extérieur de 1 mm, épaisseur 0,1 mm verre </td></tr><tr><td> Injection capillaires </td><td> Science Products </td><td> 100 Go TF 8P </td><td></td></tr><tr><td> R micromanipulateur </td><td> Leica </td><td></td><td> pour effectuer les marquages </td></tr><tr><td> Modèle P-97 </td><td> Sutter Instruments </td><td></td><td> de tirer capillaires </td></tr><tr><td> Diapositives Objets </td><td> <a href="http://www.marienfeld-superior.com/" target="_blank">Marienfeld supérieure</a> </td><td> 1000000 </td><td></td></tr><tr><td> Microscope scientifique </td><td> Zeiss </td><td> Axioskop 2 mot </td><td> pour voir les marquages ​​après photoconversion </td></tr><tr><td> Microscope scientifique </td><td> Olympe </td><td> BX50 </td><td> pour effectuer les marquages </td></tr><tr><td> Caméra vidéo Sony MC3255 </td><td> Sony / AVT Corne </td><td> Sony MC3255 </td><td> pour enregistrer marquages ​​après photoconversion </td></tr></tbody></table> Tableau 1.

labeling of single cells in the central nervous system of drosophila melanogaster

Dans cet article, nous décrivons comment étiqueter individuellement les neurones dans le SNC embryonnaire de Drosophila melanogaster par injection juxtacellulaire de la membrane lipophile Dil marqueur fluorescent. Cette méthode permet la visualisation de la morphologie des cellules neuronales dans les moindres détails. Il est possible de marquer n&#39;importe quelle cellule du système nerveux central: les corps cellulaires des neurones cibles sont visualisés sous une optique DIC ou par expression d&#39;un marqueur fluorescent génétique comme la GFP. Après marquage, le DiI peut être transformée en une tache brune permanente par photoconversion pour permettre la visualisation de la morphologie des cellules avec de la lumière transmise et de l&#39;optique DIC. Alternativement, les cellules Dil-marqués peuvent être observés directement par microscopie confocale, permettant génétiquement introduits protéines rapporteurs fluorescents à colocalised. Cette technique peut être utilisée dans n&#39;importe quel animal, quelle que soit le génotype, ce qui permet d&#39;analyser les phénotypes mutants à résolution cellule unique.

La figure 4 illustre les résultats typiques de la technique, que nous décrivons ici. Figure 4A montre un exemple de Dil interneurone unique rempli qui a été proprement photoconverted. Il démontre bien le niveau de détail de ces préparatifs offre. Lorsqu&#39;elle est vue sous une optique DIC le contexte spatial de la cellule marquée dans le tissu environnant non marqué est visible, par exemple, la position du corps de la cellule à l&#39;intérieur de l&#39;écorce et d...

Watch this Scientific Journal Video about Labeling of Single Cells in the Central Nervous System of Drosophila melanogaster at JoVE.com

Labeling of Single Cells in the Central Nervous System of Drosophila melanogaster

Nous présentons une technique pour l&#39;étiquetage des neurones simples dans le système nerveux central (SNC) de<em&gt; Drosophila</em&gt; Embryons, ce qui permet l&#39;analyse de la morphologie neuronale soit par lumière transmise ou microscopie confocale.

Étiquetage des cellules isolées dans le système nerveux central des<em&gt; Drosophila melanogaster</em

In this  article we describe how to individually label neurons in the embryonic CNS of Drosophila melanogaster by juxtacellular injection of the ...

labeling-single-cells-central-nervous-system-drosophila

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JoVE Journal

Neuroscience

Labeling of Single Cells in the Central Nervous System of Drosophila melanogaster

12.6K vues.  University of Mainz. Nous présentons une technique pour l'étiquetage des neurones simples dans le système nerveux central (SNC) de Drosophila Embryons, ce qui permet l'analyse de la morphologie neuronale soit par lumière transmise ou microscopie confocale.

Vidéo: Labeling of Single Cells in the Central Nervous System of Drosophila melanogaster

Systemic and Local Drug Delivery for Treating Diseases of the Central Nervous System in Rodent Models

Thorough preclinical testing of central nervous system (CNS) therapeutics includes a consideration of routes of administration and agent biodistribution in assessing therapeutic efficacy. Between the two major classifications of administration, local vs. systemic, systemic delivery approaches are often preferred due to ease of administration. However, systemic delivery may result in suboptimal drug concentration being achieved in the CNS, and lead to erroneous conclusions regarding agent efficacy. Local drug delivery methods are more invasive, but may be necessary to achieve therapeutic CNS drug levels. Here, we demonstrate proper technique for three routes of systemic drug delivery: intravenous injection, intraperitoneal injection, and oral gavage. In addition, we show a method for local delivery to the brain: convection-enhanced delivery (CED). The use of fluorescently-labeled compounds is included for in vivo imaging and verification of proper drug administration. The methods are presented using murine models, but can easily be adapted for use in rats.

Thorough preclinical testing of drugs that act in the central nervous system often involves assessing and comparing drug biodistribution in association with specific routes of administration. Here, three commonly used methods of systemic delivery (intravenous, intraperitoneal, and oral) as well as a method for local delivery (convection-enhanced delivery) are demonstrated in mice.

Drug Delivery systémique et locale pour traiter les maladies du système nerveux central dans les modèles rongeurs

Thorough preclinical testing of central nervous system (CNS) therapeutics includes a consideration of routes of administration and agent biodistribution ...

Recherche

Neurosciences

Visualization of the Embryonic Nervous System in Whole-mount Drosophila Embryos

The Drosophila embryo is an attractive model system for investigating the cellular and molecular basis of neuronal development. Here we describe the procedure for the visualization of Drosophila embryonic nervous system using antibodies to neuronal proteins. Since the entire embryonic peripheral nervous and central nervous systems are well characterized at the level of individual cells (Dambly-Chaudi&egrave;re et al., 1986; Bodmer et al., 1987; Bodmer et al., 1989), any aberrations to these systems can be easily identified using antibodies to different neuronal proteins. The developing embryos are collected at certain times to ensure that the embryos are in the proper developmental stages for visualization. After collection, the outer layers of the embryo, the chorion membrane and the vitelline envelope that surrounds the embryo, are removed before fixation. Embryos are then incubated with neuronal antibodies and visualized using fluorescently labeled secondary antibodies. Embryos at stages 12-17 are visualized to access the embryonic nervous system. At stage 12 the CNS germ band starts shortening and by stage 15 the definitive pattern of the commissure has been achieved. By stage 17 the CNS contracts and the PNS is fully developed (Campos-Ortega et al. 1985). Thus changes in the pattern of the PNS and CNS can be easily observed during these developmental stages.

Visualization of the Embryonic Nervous System in Whole-mount Drosophila Embryos

We describe the procedure to prepare staged Drosophila embryos for the visualization of the embryonic nervous system during embryogenesis.

La visualisation du système nerveux embryonnaire, en totalité montage Drosophile Embryons

The Drosophila embryo is an attractive model system for investigating the cellular and molecular basis of neuronal development. Here we describe the ...

Optic Nerve Transection: A Model of Adult Neuron Apoptosis in the Central Nervous System

Retinal ganglion cells (RGCs) are CNS neurons that output visual information from the retina to the brain, via the optic nerve. 
The optic nerve can be accessed within the orbit of the eye and completely transected (axotomized), cutting the axons of the entire RGC population. Optic nerve 
transection is a reproducible model of apoptotic neuronal cell death in the adult CNS 1-4. This model is particularly attractive because the vitreous
 chamber of the eye acts as a capsule for drug delivery to the retina, permitting experimental manipulations via intraocular injections. The diffusion of chemicals 
through the vitreous fluid ensures that they act upon the entire RGC population. Moreover, RGCs can be selectively transfected by applying short interfering RNAs 
(siRNAs), plasmids, or viral vectors to the cut end of the optic nerve 5-7 or injecting vectors into their target, the superior colliculus 8. 
This allows researchers to study apoptotic mechanisms in the desired neuronal population without confounding effects on other bystander neurons or surrounding glia. 
An additional benefit is the ease and accuracy with which cell survival can be quantified after injury. The retina is a flat, layered tissue and RGCs are localized in 
the innermost layer, the ganglion cell layer. The survival of RGCs can be tracked over time by applying a fluorescent tracer (3% Fluorogold) to the cut end of the 
optic nerve at the time of axotomy, or by injecting the tracer into the superior colliculus (RGC target) one week prior to axotomy. The tracer is retrogradely transported, labeling 
the entire RGC population. Because the ganglion cell layer is a monolayer (one cell thick), RGC densities can be quantified in flat-mounted tissue, without the need 
for stereology. Optic nerve transection leads to the apoptotic death of 90% of injured RGCs within 14 days postaxotomy 9-11. RGC apoptosis has a 
characteristic time-course whereby cell death is delayed 3-4 days postaxotomy, after which the cells rapidly degenerate. This provides a time window for 
experimental manipulations directed against pathways involved in apoptosis.

Optic Nerve transection is a widely used model of adult CNS injury. Ninety percent of retinal ganglion cells (RGCs) whose axons are completely transected (axotomy) die within 14 days after axotomy. This model is easily amenable to experimental manipulations and highly reproducible.

Section du nerf optique: un modèle de l&#39;apoptose neuronale des adultes dans le système nerveux central

Retinal ganglion cells (RGCs) are CNS neurons that output visual information from the retina to the brain, via the optic nerve. 
The optic nerve can be ...

Multimodal Imaging of Stem Cell Implantation in the Central Nervous System of Mice

During the past decade, stem cell transplantation has gained increasing interest as primary or secondary therapeutic modality for a variety of diseases, both in preclinical and clinical studies. However, to date results regarding functional outcome and/or tissue regeneration following stem cell transplantation are quite diverse. Generally, a clinical benefit is observed without profound understanding of the underlying mechanism(s)1. Therefore, multiple efforts have led to the development of different molecular imaging modalities to monitor stem cell grafting with the ultimate aim to accurately evaluate survival, fate and physiology of grafted stem cells and/or their micro-environment. Changes observed in one or more parameters determined by molecular imaging might be related to the observed clinical effect. In this context, our studies focus on the combined use of bioluminescence imaging (BLI), magnetic resonance imaging (MRI) and histological analysis to evaluate stem cell grafting.
BLI is commonly used to non-invasively perform cell tracking and monitor cell survival in time following transplantation2-7, based on a biochemical reaction where cells expressing the Luciferase-reporter gene are able to emit light following interaction with its substrate (e.g. D-luciferin)8, 9. MRI on the other hand is a non-invasive technique which is clinically applicable10 and can be used to precisely locate cellular grafts with very high resolution11-15, although its sensitivity highly depends on the contrast generated after cell labeling with an MRI contrast agent. Finally, post-mortem histological analysis is the method of choice to validate research results obtained with non-invasive techniques with highest resolution and sensitivity. Moreover end-point histological analysis allows us to perform detailed phenotypic analysis of grafted cells and/or the surrounding tissue, based on the use of fluorescent reporter proteins and/or direct cell labeling with specific antibodies.
In summary, we here visually demonstrate the complementarities of BLI, MRI and histology to unravel different stem cell- and/or environment-associated characteristics following stem cell grafting in the CNS of mice. As an example, bone marrow-derived stromal cells, genetically engineered to express the enhanced Green Fluorescent Protein (eGFP) and firefly Luciferase (fLuc), and labeled with blue fluorescent micron-sized iron oxide particles (MPIOs), will be grafted in the CNS of immune-competent mice and outcome will be monitored by BLI, MRI and histology (Figure 1).

This article describes an optimized sequence of events for multimodal imaging of cellular grafts in rodent brain using: (i) in vivo bioluminescence and magnetic resonance imaging, and (ii) post mortem histological analysis. Combining these imaging modalities on a single animal allows cellular graft evaluation with high resolution, sensitivity and specificity.

Imagerie multimodale d&#39;implantation de cellules souches dans le système nerveux central de souris

During the past decade, stem cell transplantation has gained increasing interest as primary or secondary therapeutic modality for a variety of diseases, ...

Production of Lentiviral Vectors for Transducing Cells from the Central Nervous System

Efficient gene delivery in the central nervous system (CNS) is important in studying gene functions, modeling neurological diseases and developing therapeutic approaches. Lentiviral vectors are attractive tools in transduction of neurons and other cell types in CNS as they transduce both dividing and non-dividing cells, support sustained expression of transgenes, and have relatively large packaging capacity and low toxicity 1-3. Lentiviral vectors have been successfully used in transducing many neural cell types in vitro 4-6 and in animals 7-10.
Great efforts have been made to develop lentiviral vectors with improved biosafety and efficiency for gene delivery. The current third generation replication-defective and self-inactivating (SIN) lentiviral vectors are depicted in Figure 1. The required elements for vector packaging are split into four plasmids. In the lentiviral transfer plasmid, the U3 region in the 5' long terminal repeat (LTR) is replaced with a strong promoter from another virus. This modification allows the transcription of the vector sequence independent of HIV-1 Tat protein that is normally required for HIV gene expression 11. The packaging signal (&Psi;) is essential for encapsidation and the Rev-responsive element (RRE) is required for producing high titer vectors. The central polypurine tract (cPPT) is important for nuclear import of the vector DNA, a feature required for transducing non-dividing cells 12. In the 3' LTR, the cis-regulatory sequences are completely removed from the U3 region. This deletion is copied to 5' LTR after reverse transcription, resulting in transcriptional inactivation of both LTRs. Plasmid pMDLg/pRRE contains HIV-1 gag/pol genes, which provide structural proteins and reverse transcriptase. pRSV-Rev encodes Rev which binds to the RRE for efficient RNA export from the nucleus. pCMV-G encodes the vesicular stomatitis virus glycoprotein (VSV-G) that replaces HIV-1 Env. VSV-G expands the tropism of the vectors and allows concentration via ultracentrifugation 13. All the genes encoding the accessory proteins, including Vif, Vpr, Vpu, and Nef are excluded in the packaging system. The production and manipulation of lentiviral vectors should be carried out according to NIH guidelines for research involving recombinant DNA (<a href="http://oba.od.nih.gov/oba/rac/Guidelines/NIH_Guidelines.pdf" target="_blank">http://oba.od.nih.gov/oba/rac/Guidelines/NIH_Guidelines.pdf</a>). An approval from individual Institutional Biological and Chemical Safety Committee may be required before using lentiviral vectors. Lentiviral vectors are commonly produced by cotransfection of 293T cells with lentiviral transfer plasmid and the helper plasmids encoding the proteins required for vector packaging. Many lentiviral transfer plasmids and helper plasmids can be obtained from Addgene, a non-profit plasmid repository (<a href="http://www.addgene.org/" target="_blank">http://www.addgene.org/</a>). Some stable packaging cell lines have been developed, but these systems provide less flexibility and their packaging efficiency generally declines over time 14, 15. Commercially available transfection kits may support high efficiency of transfection 16, but they can be very expensive for large scale vector preparations. Calcium phosphate precipitation methods provide highly efficient transfection of 293T cells and thus provide a reliable and cost effective approach for lentiviral vector production.
In this protocol, we produce lentiviral vectors by cotransfection of 293T cells with four plasmids based on the calcium phosphate precipitation principle, followed by purification and concentration with ultracentrifugation through a 20% sucrose cushion. The vector titers are determined by fluorescence- activated cell sorting (FACS) analysis or by real time qPCR. The production and titration of lentiviral vectors in this protocol can be finished with 9 days. We provide an example of transducing these vectors into murine neocortical cultures containing both neurons and astrocytes. We demonstrate that lentiviral vectors support high efficiency of transduction and cell type-specific gene expression in primary cultured cells from CNS.

In this protocol we describe production, purification and titration of lentiviral vectors. We provide an example of lentiviral vector-mediated gene delivery in primary cultured neurons and astrocytes. Our methods may also apply to other cell types in vitro and in vivo.

La production de vecteurs lentiviraux pour les cellules de transduction du Système Nerveux Central

Efficient gene delivery in the central nervous system (CNS) is important in studying gene functions, modeling neurological diseases and developing ...

An Injury Paradigm to Investigate Central Nervous System Repair in Drosophila

An experimental method has been developed to investigate the cellular responses to central nervous system (CNS) injury using the fruit-fly Drosophila. Understanding repair and regeneration in animals is a key question in biology. The damaged human CNS does not regenerate, and understanding how to promote the regeneration is one of main goals of medical neuroscience. The powerful genetic toolkit of Drosophila can be used to tackle the problem of CNS regeneration.
A lesion to the CNS ventral nerve cord (VNC, equivalent to the vertebrate spinal cord) is applied manually with a tungsten needle. The VNC can subsequently be filmed in time-lapse using laser scanning confocal microscopy for up to 24 hr to follow the development of the lesion over time. Alternatively, it can be cultured, then fixed and stained using immunofluorescence to visualize neuron and glial cells with confocal microscopy. Using appropriate markers, changes in cell morphology and cell state as a result of injury can be visualized. With ImageJ and purposely developed plug-ins, quantitative and statistical analyses can be carried out to measure changes in wound size over time and the effects of injury in cell proliferation and cell death. These methods allow the analysis of large sample sizes. They can be combined with the powerful genetics of Drosophila to investigate the molecular mechanisms underlying CNS regeneration and repair.

An Injury Paradigm to Investigate Central Nervous System Repair in Drosophila

An injury paradigm using the Drosophila larval ventral nerve cord to investigate central nervous system regeneration and repair is described. Stabbing followed by laser scanning confocal microscopy in time-lapse and fixed specimens, combined with quantitative analysis with purposefully developed software and genetics, are used to investigate the molecular mechanisms of CNS regeneration and repair.

Un paradigme d&#39;enquêter sur les blessures du système nerveux central de réparation de<em&gt; Drosophila</em

An experimental method has been developed to investigate the cellular responses to central nervous system (CNS) injury using the fruit-fly Drosophila. ...

Direct Intraventricular Delivery of Drugs to the Rodent Central Nervous System

Due to an inability to cross the blood brain barrier, certain drugs need to be directly delivered into the central nervous system (CNS). Our lab focuses specifically on antisense oligonucleotides (ASOs), though the techniques shown in the video here can also be used to deliver a plethora of other drugs to the CNS. Antisense oligonucleotides (ASOs) have the capability to knockdown sequence-specific targets 1 as well as shift isoform ratios of specific genes 2. To achieve widespread gene knockdown or splicing in the CNS of mice, the ASOs can be delivered into the brain using two separate routes of administration, both of which we demonstrate in the video.
The first uses Alzet osmotic pumps, connected to a catheter that is surgically implanted into the lateral ventricle. This allows the ASOs to be continuously infused into the CNS for a designated period of time. The second involves a single bolus injection of a high concentration of ASO into the right lateral ventricle. Both methods use the mouse cerebral ventricular system to deliver the ASO to the entire brain and spinal cord, though depending on the needs of the study, one method may be preferred over the other.

We describe a method to target drugs to the central nervous system by either implanting a catheter or performing a bolus injection into the right lateral ventricle in mice. We focus specifically on the delivery of antisense oligonucleotides. This technique is readily adaptable to other drugs and to rats.

Livraison intraventriculaire directe des médicaments pour le système nerveux central rongeurs

Due to an inability to cross the blood brain barrier, certain drugs need to be directly delivered into the central nervous system (CNS). Our lab focuses ...

In vivo Interrogation of Central Nervous System Translatome by Polyribosome Fractionation

Multiple processes are involved in gene expression including transcription, translation and stability of mRNAs and proteins. Each of these steps are tightly regulated, affecting the final dynamics of protein abundance. Various regulatory mechanisms exist at the translation step, rendering mRNA levels alone an unreliable indicator of gene expression. In addition, local regulation of mRNA translation has been particularly implicated in neuronal functions, shifting &#39;translatomics&#39; to the focus of attention in neurobiology. The presented method can be used to bridge transcriptomics and proteomics.
Here we describe essential modifications to the technique of polyribosome fractionation, which interrogates the translatome based on the association of actively translated mRNAs to multiple ribosomes and their differential sedimentation in sucrose gradients. Traditionally, working with in vivo samples, particularly of the central nervous system (CNS), has proven challenging due to the restricted amounts of material and the presence of fatty tissue components. In order to address this, the described protocol is specifically optimized for use with minimal amount of CNS material, as demonstrated by the use of single mouse spinal cord and brain. Briefly, CNS tissues are extracted and translating ribosomes are immobilized on mRNAs with cycloheximide. Myelin flotation is then performed to remove lipid rich components. Fractionation is performed on a sucrose gradient where mRNAs are separated according to their ribosomal loading. Isolated fractions are suitable for a range of downstream assays, including new genome wide assay technologies.

In vivo Interrogation of Central Nervous System Translatome by Polyribosome Fractionation

This protocol illustrates essential modifications of polyribosome fractionation in order to study the translatome of in vivo CNS samples. It allows global assessment of translation and transcription regulation through the isolation and comparison of total RNA to ribosome bound RNA fractions.

En Interrogation in vivo de système nerveux central Translatome par polyribosome fractionnement

Multiple processes are involved in gene expression including transcription, translation and stability of mRNAs and proteins. Each of these steps are ...

In vivo Optogenetic Stimulation of the Rodent Central Nervous System

The ability to probe defined neural circuits in awake, freely-moving animals with cell-type specificity, spatial precision, and high temporal resolution has been a long sought tool for neuroscientists in the systems-level search for the neural circuitry governing complex behavioral states. Optogenetics is a cutting-edge tool that is revolutionizing the field of neuroscience and represents one of the first systematic approaches to enable causal testing regarding the relation between neural signaling events and behavior. By combining optical and genetic approaches, neural signaling can be bi-directionally controlled through expression of light-sensitive ion channels (opsins) in mammalian cells. The current protocol describes delivery of specific wavelengths of light to opsin-expressing cells in deep brain structures of awake, freely-moving rodents for neural circuit modulation. Theoretical principles of light transmission as an experimental consideration are discussed in the context of performing in vivo optogenetic stimulation. The protocol details the design and construction of both simple and complex laser configurations and describes tethering strategies to permit simultaneous stimulation of multiple animals for high-throughput behavioral testing.

In vivo Optogenetic Stimulation of the Rodent Central Nervous System

Optogenetics has become a powerful tool for use in behavioral neuroscience experiments. This protocol offers a step-by-step guide to the design and set-up of laser systems, and provides a full protocol for carrying out multiple and simultaneous in vivo optogenetic stimulations compatible with most rodent behavioral testing paradigms.

In vivo optogénétiques stimulation du système nerveux central pour rongeurs

The ability to probe defined neural circuits in awake, freely-moving animals with cell-type specificity, spatial precision, and high temporal resolution ...

Optical Clearing of the Mouse Central Nervous System Using Passive CLARITY

Traditionally, tissue visualization has required that the tissue of interest be serially sectioned and imaged, subjecting each tissue section to unique non-linear deformations, dramatically hampering one's ability to evaluate cellular morphology, distribution and connectivity in the central nervous system (CNS). However, optical clearing techniques are changing the way tissues are visualized. These approaches permit one to probe deeply into intact organ preparations, providing tremendous insight into the structural organization of tissues in health and disease. Techniques such as Clear Lipid-exchanged Acrylamide-hybridized Rigid Imaging-compatible Tissue-hYdrogel (CLARITY) achieve this goal by providing a matrix that binds important biomolecules while permitting light-scattering lipids to freely diffuse out. Lipid removal, followed by refractive index matching, renders the tissue transparent and readily imaged in 3 dimensions (3D). Nevertheless, the electrophoretic tissue clearing (ETC) used in the original CLARITY protocol can be challenging to implement successfully and the use of a proprietary refraction index matching solution makes it expensive to use the technique routinely. This report demonstrates the implementation of a simple and inexpensive optical clearing protocol that combines passive CLARITY for improved tissue integrity and 2,2&#8242;-thiodiethanol (TDE), a previously described refractive index matching solution.

Optical clearing techniques are revolutionizing the way tissues are visualized. In this report we describe modifications of the original Clear Lipid-exchanged Acrylamide-hybridized Rigid Imaging-compatible Tissue-hYdrogel (CLARITY) protocol that yields more consistent and less expensive results.

Clearing optique du système nerveux central de souris utilisant CLARITY passive

Traditionally, tissue visualization has required that the tissue of interest be serially sectioned and imaged, subjecting each tissue section to unique ...