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J., Sink, H., Kolodkin, A. L., Goodman, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Semaphorin+II+can+function+as+a+selective+inhibitor+of+specific+synaptic+arborizations.">Semaphorin II can function as a selective inhibitor of specific synaptic arborizations.</a> Cell. 81, 631-639 (1995).</li><li>Murray, M. J., Whitington, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+roundabout+on+growth+cone+dynamics,+filopodial+length,+and+growth+cone+morphology+at+the+midline+and+throughout+the+neuropile.">Effects of roundabout on growth cone dynamics, filopodial length, and growth cone morphology at the midline and throughout the neuropile.</a> Journal of Neuroscience. 19, 7901-7912 (1999).</li><li>Murray, M. J., Merritt, D. J., Brand, A. H., Whitington, P. 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. 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Die Autoren erklären, dass sie keine finanziellen Interessen haben.

Ein großer Vorteil von Drosophila als Modellsystem ist, dass sie eine Analyse der Entwicklung und Funktion auf der Ebene einzelner Zellen ermöglicht. Dies ist besonders hilfreich in Bezug auf das Nervensystem, wo die Vielfalt von Zelltypen ist außergewöhnlich hoch und die Funktion und Morphologie der benachbarten Zellen können ganz anders sein. Das Verfahren wir hier ermöglicht die Etikettierung von einzelnen Neuronen mit einem Farbstoff, der entweder in eine dauerhafte Färbu...

Wissen über neuronale Morphologie auf der Ebene der einzelnen Zellen ist eine wichtige Voraussetzung für das Verständnis neuronaler Verschaltungen und ZNS-Funktion. So wird aus den frühesten Tagen der Neurowissenschaften haben Forscher versucht, einzelne Zelle Kennzeichnung Techniken (siehe 7 für eine historische Aufarbeitung dieser Ausgabe) zu entwickeln. Klassische Methoden wie Golgi-Färbung eine ausgezeichnete Auflösung von neuronale Morphologie jedoch nicht geeignet sind, wenn man eine bestimmte Art von Neuronen in einer gerichteten Weise gekennzeichnet werden, wie Färbung erfolgt in einer zufälligen Weise sucht. Die Entwicklung von Verfahren zum Anfärben einzelner Zellen durch intrazelluläre oder juxtacellular Injektion von Farbstoffen von einer Mikroelektrode adressiert die Anforderung der spezifischen Markierung. Die Anwendung der einzelnen Neurons Farbstoffinjektion zu Drosophila eine große Herausforderung, wegen der geringen Größe der sowohl dem Organismus und seiner Neuronen. Dennoch einzelnen Neurons Färbung von embryonalen Drosophila </em&gt; Neuronen wurde Mitte der 1980er-Jahre im Labor von Corey Goodman 15 erreicht. Während das Verfahren war eminent nützlich und hat einige wichtige Einblicke in Mechanismen für die neuronale Entwicklung in Drosophila in den letzten 20-30 Jahren (z. B. 2, 10), haben viele Arbeitnehmer davon entfernt gescheut, vor allem wegen seiner technischen Anforderungen. Die Verfügbarkeit in den letzten Jahren der genetischen Techniken zur neuronalen Kennzeichnung in Drosophila wurde auch auf die Unbeliebtheit des einzelnen Neurons Farbstoffinjektion beigetragen. GAL4-gerichtete Expression von Membran-gezielte GFP-Konstrukte können eine hervorragende Auflösung von neuronalen Morphologie 1, 20. Allerdings hat diese Methode bestimmte Einschränkungen: die oft unvermeidlichen Expression von GFP in mehrere Zellen können die Struktur der einzelnen Neuronen zu verschleiern und eine GAL4 Fahrerpaarung möglicherweise nicht zur Verfügung, um die Expression in einem bestimmten Neuron von Interesse zu fahren. Die marcm (Mosaic Analyse mit einem Repressible Zellmarker) Methode 8 bieten kann Etikettieren von im Wesentlichen jedem Neuron in der einzelnen Zelle Ebene, aber nicht erfolgreich im Embryo und frühe Larve wegen der langsamen Umsatz des GAL80-Proteins verwendet werden. Angesichts dieser Einschränkungen der genetischen Kennzeichnung, glauben wir, dass einzelne Neuron Farbstoff Injektion in den Drosophila-Embryo bleibt eine wertvolle Technik und verdient eine breitere Anwendung. Um dieses Ziel zu fördern, geben wir hier eine detaillierte Beschreibung des Verfahrens. Eine Abbildung der Leistung wird durch unsere jüngsten Berücksichtigung der Morphologie des kompletten Satz von Interneuronen abdominalen Neuromeren des späten Drosophila-Embryo 14 vorgesehen. Diese Studie, die sowohl die morphologische Variabilität der einzelnen neuronalen Zelltypen und die Prinzipien der Neuromer Organisation im ZNS des Embryos zeigten, wären nicht mit irgendeinem anderen aktuell verfügbaren Markierungsverfahren möglich gewesen.

<table border="1"><tbody><tr><td> Name des Reagenz / Material </td><td> Firma </td><td> Katalog-Nummer </td><td> Kommentare </td></tr><tr><td></td><td></td><td></td><td> REAGENZIEN </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 in 100 mM Tris-HCl, pH 7,4 </td></tr><tr><td> DiI </td><td> Invitrogen / Molecular Probes </td><td> <a href="http://products.invitrogen.com/ivgn/product/D282" target="_blank">D-282</a> </td><td> 1 mg / ml in Ethanol </td></tr><tr><td> <a href="http://www.merckmillipore.com/germany/chemicals/formaldehydloesung-min-37-prozent/MDA_CHEM-104002/p_Wt6b.s1L6pAAAAEWpOEfVhTl" target="_blank">Formaldehyd</a> </td><td> Merck Millipore </td><td></td><td> 7,4% in PBS </td> &lt;/ Tr&gt; <tr><td> Glycerol </td><td> <a href="http://www.carlroth.com/catalogue/" target="_blank">Roth</a> </td><td> 3783 </td><td> 70% in PBS </td></tr><tr><td> Heptan Kleber </td><td> Beiersdorf AG </td><td> Cello 31-39-30 * </td><td> verdünnen ca. 1-1 mit n-Heptan </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> EQUIPMENT </td></tr><tr><td> Konfokalen Mikroskop </td><td> Leica </td><td> TCS SP2 </td><td> zu sehen und zu dokumentieren Beschriftungen in der Fluoreszenz </td></tr><tr><td> DC - amplifier </td><td> Dragan Konzern </td><td> Cornerstone ION-100 </td><td> die Markierungen durchzuführen </td></tr><tr><td> Deckgläser </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> Deckgläser </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> Seziermikroskop </td><td> Leica </td><td> MZ8 </td><td> vorzubereiten und disect Embryonen </td></tr><tr><td> Flache Kapillaren </td><td> <a href="http://www.hilgenberg-gmbh.de/" target="_blank">Hilgenberg</a> </td><td></td><td> Außendurchmesser 1 mm; Glas Dicke 0,1 mm </td></tr><tr><td> Injektionskapillaren </td><td> Science Products </td><td> GB 100 TF 8P </td><td></td></tr><tr><td> Micromanipulator R </td><td> Leica </td><td></td><td> die Markierungen durchzuführen </td></tr><tr><td> Modell P-97 </td><td> Sutter Instruments </td><td></td><td> Kapillaren ziehen </td></tr><tr><td> Objektträger </td><td> <a href="http://www.marienfeld-superior.com/" target="_blank">Marienfeld Superior</a> </td><td> 1000000 </td><td></td></tr><tr><td> Scientific Mikroskop </td><td> Zeiss </td><td> Axioskop 2 mot </td><td> um Markierungen nach Photokonversion anzeigen </td></tr><tr><td> Scientific Mikroskop </td><td> Olymp </td><td> BX50 </td><td> die Markierungen durchzuführen </td></tr><tr><td> Sony MC3255 Video Camera </td><td> Sony / AVT Horn </td><td> Sony MC3255 </td><td> um Markierungen nach Photokonversion aufzeichnen </td></tr></tbody></table> Tabelle 1.

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

In diesem Artikel beschreiben wir, wie Sie individuell beschriften Neuronen in den embryonalen ZNS von Drosophila melanogaster durch juxtacellular Injektion des lipophilen fluoreszierende Membran Marker DiI. Diese Methode erlaubt die Visualisierung von neuronalen Zellmorphologie im Detail. Es ist möglich, eine beliebige Zelle im ZNS kennzeichnen: Zellkörper Zielneuronen stehen unter DIC Optik oder durch Expression eines fluoreszierenden genetischen Marker wie GFP visualisiert. Nach der Markierung kann die DiI in einen permanenten braunen Fleck von Photokonversion umgewandelt werden zur Visualisierung der Zellmorphologie mit Durchlicht-und DIC-Optik ermöglichen. Alternativ können die DiI-markierten Zellen direkt mit konfokale Mikroskopie beobachtet werden, wodurch gentechnisch eingeführte fluoreszierenden Reporter-Proteine ​​zu colocalised werden. Die Technik kann bei einem Tier verwendet werden, unabhängig von Genotyp, die es ermöglichen, bei Mutantenphänotypen Einzelzelle Auflösung zu analysieren.

Abbildung 4 zeigt typische Ergebnisse der Technik beschreiben wir hier. 4A zeigt ein Beispiel für eine DiI gefüllt einzelnen Interneuronen, die sauber lichtinduziert wurde. Es schön zeigt die Menge der Details dieser Präparate Angebot. Wenn unter DIC Optik angesehen der räumliche Kontext der markierten Zelle innerhalb der nicht-markierten umgebende Gewebe sichtbar wird, z. B. die Position der Zelle innerhalb des Körpers Cortex und der Faser Vorsprung innerhalb des Neuropi...

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

Wir stellen eine Technik zur Markierung von einzelnen Neuronen im Zentralnervensystem (ZNS) von<em&gt; Drosophila</em&gt; Embryonen, die die Analyse der neuronalen Morphologie entweder Durchlicht oder konfokalen Mikroskopie ermöglicht.

Beschriften einzelner Zellen im zentralen Nervensystem<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

Research

JoVE Journal

Neuroscience

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

12.7K Aufrufe.  University of Mainz. Wir stellen eine Technik zur Markierung von einzelnen Neuronen im Zentralnervensystem (ZNS) von Drosophila Embryonen, die die Analyse der neuronalen Morphologie entweder Durchlicht oder konfokalen Mikroskopie ermöglicht.

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

Single Sensillum Recordings in the Insects Drosophila melanogaster and Anopheles gambiae

The sense of smell is essential for insects to find foods, mates, predators, and oviposition sites3. Insect olfactory sensory neurons (OSNs) are enclosed in sensory hairs called sensilla, which cover the surface of olfactory organs. The surface of each sensillum is covered with tiny pores, through which odorants pass and dissolve in a fluid called sensillum lymph, which bathes the sensory dendrites of the OSNs housed in a given sensillum. The OSN dendrites express odorant receptor (OR) proteins, which in insects function as odor-gated ion channels4, 5. The interaction of odorants with ORs either increases or decreases the basal firing rate of the OSN. This neuronal activity in the form of action potentials embodies the first representation of the quality, intensity, and temporal characteristics of the odorant6, 7.
Given the easy access to these sensory hairs, it is possible to perform extracellular recordings from single OSNs by introducing a recording electrode into the sensillum lymph, while the reference electrode is placed in the lymph of the eye or body of the insect. In Drosophila, sensilla house between one and four OSNs, but each OSN typically displays a characteristic spike amplitude. Spike sorting techniques make it possible to assign spiking responses to individual OSNs. This single sensillum recording (SSR) technique monitors the difference in potential between the sensillum lymph and the reference electrode as electrical spikes that are generated by the receptor activity on OSNs1, 2, 8. Changes in the number of spikes in response to the odorant represent the cellular basis of odor coding in insects. Here, we describe the preparation method currently used in our lab to perform SSR on Drosophila melanogaster and Anopheles gambiae, and show representative traces induced by the odorants in a sensillum-specific manner.

Single Sensillum Recordings in the Insects Drosophila melanogaster and Anopheles gambiae

Electrophysiological responses of olfactory sensory neurons to odorants can be measured in insects using single sensillum recordings. In this video article we will demonstrate how to perform single sensillum recordings in the antennae of the vinegar fly (Drosophila melanogaster) and the maxillary palps of the malaria mosquito (Anopheles gambiae).

Einzel Sensillum Recordings in der Insekten Drosophila melanogaster Und Anopheles gambiae</em

The sense of smell is essential for insects to find foods, mates, predators, and oviposition sites3. Insect olfactory sensory neurons (OSNs) are enclosed ...

Forschung

Neurowissenschaften

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.

Visualisierung des embryonalen Nervensystems 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 ...

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.

Optic Nerve Durchtrennung: Ein Modell des Adult Neuron Apoptose in das zentrale Nervensystem

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.

Multimodale Bildgebung von Stem Cell Implantation in das zentrale Nervensystem der Mäuse

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.

Die Produktion von lentiviralen Vektoren für die Transduktion von Zellen aus dem Zentralen Nervensystems

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.

Eine Verletzung Paradigm Central Nervous System Repair in Untersuchen<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.

Direkt Intraventrikuläre Abgabe von Arzneimitteln an die Nager 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 ...

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.

In-vivo-Abfrage des Zentralen Nervensystems durch Translatome Polyribosom Fraktionierung

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 optogenetische Stimulation des Nager 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 ...

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.

Optische Clearing der Maus Zentralnervensystem Passive CLARITY Verwendung

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