Queremos agradecer Arumae Urmas para compartilhar um protocolo de colágeno e Jutta Fey e Ursula Hinz para assistência técnica excelente. Além disso queremos agradecer a Christian F. Ackermann, Ulrike Engel ea Nikon Imaging Center da Universidade de Heidelberg e também Joachim Kirsch por gentilmente ajuda para o shoting vídeo. O trabalho foi parcialmente financiado pelo Deutsche Forschungsgemeinschaft (SFB 592).

1. Preparação de géis de colagénio <ol><li> Prepara-se uma média de valores, contendo 455 ul de MEM de 10x, 112 ul de 7,5% de NaHCO 3, 50 ul de glutamina e NaOH. A concentração e a quantidade de NaOH depende da preparação de colagénio da cauda de rato (ver 1.2), o volume final do meio de estoque sendo 1000 ul. </li><li> Prepare-colagénio da cauda de rato de acordo com Ebendal (1). Armazene a solução de colagénio, a 4 ° C. A degradação da solução de colagénio não pôde ser observado. Após a preparação de um novo lote, estimar a concentração de NaOH necessária para o meio de stock (ver 1.1). Utilizar o indicador de pH do meio para a titulação da quantidade e da concentração de NaOH. 800 ul colágeno rato-cauda ácida tem que virar um tom de vermelho quando misturado com 210 ul do meio de ações. Se a concentração de NaOH é muito baixa a solução de colagénio ficará amarela, devido a que o indicador de pH do meio. Adicione o colágeno para o meio e misture sem producing bolhas. Execute essas etapas em gelo. A polimerização ocorre dentro de 2 horas após a solução de colagénio e o meio de estoque foram misturados e a nova solução é incubada a 37 ° C. Testar isso antes de iniciar um experimento. 1.3) Misture 800 ml de solução de colágeno com 210 ul de meio de ações (ver 1.2). Coloque 100 ul desta solução nos poços de uma lâmina de câmara 8 também. Incubar as lâminas a 37 ° C, 5% de CO 2 e de condições de humidade numa incubadora de cultura de células. Preparar os géis de colagénio em um banco de cultura de células e condições estéreis. O colagénio é gelatinizado dentro de 2 horas. </li></ol> 2. Dissecação de SCGs embrionárias <ol><li> Colheita de embriões em tempo ratas grávidas (E16-18) do útero e mantê-los em PBS até mais necessário. </li><li> Dissecar um embrião a partir do âmnio. Decapitar o caudal embrião do nível clavicular. Fixe a cabeça em um prato fundo de silício com &quot;inseto-agulhas&quot;. O lado ventral da cabeça tem de enfrentar a você umaD Você tem que ver a região submandibular. A fixação permite a fácil preparação. </li><li> Remova a pele da região submandibular esquerda e para a direita e com ele o tecido conjuntivo sub-cutânea. </li><li> Retire as glândulas salivares submandibulares de sua localização para limpar a vista para o hióide, os músculos infrahyoidal eo músculo esternocleidomastóideo. </li><li> Remova os músculos cuidadosamente para limpar a vista para a laringe ea traquéia. Remover a traqueia e laringe. As artérias carótidas são, então, visível em ambos os lados sobre os músculos pré-vertebrais. O GCS está localizado na bifurcação das artérias carótidas e tem uma forma oval. Remova cuidadosamente os gânglios e colocá-los em PBS. Remover os gânglios suavemente a partir das ferramentas de dissecação, se forem aderindo a elas. É vantajoso usar uma pinça, bem como um porta-agulhas montado com uma &quot;agulha de insectos&quot; para a remoção do SCG. </li><li> Uma vez em PBS, armazenar os gânglios à temperatura ambiente em PBS até dissecados enougânglios gh. Em seguida, limpe os gânglios dos vasos sanguíneos e tecido conjuntivo. Realizar a dissecção SCG e limpeza sob um microscópio de dissecação colocado debaixo de um banco de fluxo laminar. </li><li> Finalmente, coloque os gânglios explantados para os géis de colagénio gelatinizadas com a ajuda de agulhas de seringa montado em uma seringa para uma manipulação mais fácil. </li><li> Incubar os explantes SCG sobre o colagénio gelatinizado numa incubadora de cultura de células a 37 ° C, com as condições de 5% de CO2 e humidade. </li></ol> 3. Tratamento de Explantes SCG <ol><li> Após 1-2 horas de incubação, cobrir o colagénio explante SCG contendo meio de cultura com 100 uL contendo Neurobasal célula B27 suplemento, glutamina e antibióticos. Agora, os poços das lâminas de câmara conter um volume de 200 ul (100 e 100 ul de gel ul de meio). Adicione outro ul 200 do meio, no entanto agora contendo NGF (60 ng / ml) para facilitar o crescimento axonal. Por conseguinte, a concentração final de NGF é de 30 ng / ml. </li><li><ol class="lalpha"><li> Para investigar o aparecimento de SC migração, adicione fatores adicionais diretamente no dia in vitro 0 (DIV0). Dissolver os fatores do meio de NGF contendo em o dobro da concentração necessária (2). </li><li> A fim de analisar o impacto no SCS, que já começaram a migrar ao longo de axônios, adicione fatores adicionais a DIV3 até DIV4 (paragem potencial do experimento). Para este fim, retirar cuidadosamente 180 ul da solução, em DIV3, e adiciona-se 200 ul de meio novo NGF contendo e os factores adicionais de interesse na concentração dupla (2). </li></ol></li></ol> 4. Lapso de tempo de imagem Use um microscópio invertido para análises. Diferentes objectivos podem ser usados, que define o campo de visão e ampliação. Um aspecto importante, contudo, é a distância de trabalho do objectivo utilizado, como imagens dos explantes SCG é realizada por meio da lâmina de vidro e o colagéniogel. A taxa de quadros de gravação de 1/10-30 minutos, mostrou bons resultados (2). No entanto, este aspecto tem de ser ajustado para a questão científica. Uma câmara CCD normal pode ser utilizado para a obtenção da imagem. Para imagiologia de lapso de tempo de uma câmara de incubação de células de cultura tem que ser ligado à fase do microscópio. Incubar o tecido durante a imagiologia, a 37 ° C, com as condições de 5% de CO2 e humidade. Inicie a incubação de uma hora antes do início do sistema de geração de imagens. Isto permite que as partes do microscópio (por exemplo, objectivo), incluindo a câmara de corrediça para ajustar a temperatura e evita desvios de temperatura induzidas. Definir as áreas específicas de análises (dentro de explante e entre diferentes explantes) com a ajuda do software de microscópio e uma fase motorizada controlada por software (configuração multiposições) para análises simultâneas de diferentes condições aplicadas aos explantes SCG. Por lapso de tempo tecidual de tipo selvagem, bem como nos tecidos dos animais transgénicos pode ser usadomarcando o SCs (S100B: GFP) (3). Para fluoróforos de imagem de uma fonte de luz fluorescente deve ser implementado na configuração micropscope. Use filtros padrão. 5. Quantificação das distâncias de migração SC <ol><li> No ponto final (DIV4 por exemplo), corrigir os géis de colágeno com PFA 4% no slide câmara para 3-4 horas. Consecutivamente, os géis de colagénio lavar 5 vezes durante 10 min com PBS. Aplicar protocolos padrão para a imunocitoquímica (2). Se você é novo para a preparação de SCGs, verificar a identidade do gânglio como um gânglio simpático por imuno-histoquímica contra tirosina hidroxilase (TH) um marcador comum para células catecolaminérgicos. Durante imunohistoquímica (após o anticorpo primário), transferir os explantes géis de colagénio contendo a placas de 24 poços, os quais têm um volume maior, o que é benéfico para a lavagem do gel. </li><li> Depois de imuno-histoquímica, coloque cuidadosamente o gel de colágeno em lâminas de vidro. Cuidadosamenteremover a solução restante e deixe secar o colágeno / encolher a duas dimensões. Isso permite que as medições fáceis de distâncias (2). Depois disso, montar as amostras. </li><li> Finalmente, medir distâncias de migração com a ajuda de software Fiji (NIH). Não plugins especiais são necessários para esse fim. Para permitir que medidas corretas em um, verificar os metadados de imagem correta e as configurações no Fiji, imagem e escala. Use Fiji também para a quantificação das células. </li></ol>

<ol>
	<li>Ebendal, T., Rush, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Use of collagen gels to bioassay nerve growth factor activity. IBRO Handh, (1989).</li><li>Heermann, S., Schm&#195;cker, J., Hinz, U., Rickmann, M., Unterbarnscheidt, T., Schwab, M. H., Krieglstein, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuregulin+1+type+III/ErbB+signaling+is+crucial+for+Schwann+cell+colonization+of+sympathetic+axons.">Neuregulin 1 type III/ErbB signaling is crucial for Schwann cell colonization of sympathetic axons.</a> PloS One. 6 (12), e28692 (2011).</li><li>Zuo, Y., Lubischer, J. L., Kang, H., Tian, L., Mikesh, M., Marks, A., Scofield, V. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescent+proteins+expressed+in+mouse+transgenic+lines+mark+subsets+of+glia,+neurons,+macrophages,+and+dendritic+cells+for+vital+examination.">Fluorescent proteins expressed in mouse transgenic lines mark subsets of glia, neurons, macrophages, and dendritic cells for vital examination.</a> The Journal of Neuroscience. The Official Journal of the Society for Neuroscience. 24 (49), 10999-11009 (2004).</li><li>Levi-Montalcini, R., Booker, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EXCESSIVE+GROWTH+OF+THE+SYMPATHETIC+GANGLIA+EVOKED+BY+A+PROTEIN+ISOLATED+FROM+MOUSE+SALIVARY+GLANDS.">EXCESSIVE GROWTH OF THE SYMPATHETIC GANGLIA EVOKED BY A PROTEIN ISOLATED FROM MOUSE SALIVARY GLANDS.</a> Proceedings of the National Academy of Sciences of the United States of America. 46 (3), 373-384 (1960).</li><li>Meintanis, S., Thomaidou, D., Jessen, K. R., Mirsky, R., Matsas, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+neuron-glia+signal+beta-neuregulin+promotes+Schwann+cell+motility+via+the+MAPK+pathway.">The neuron-glia signal beta-neuregulin promotes Schwann cell motility via the MAPK pathway.</a> Glia. 34 (1), 39-51 (2001).</li><li>Yamauchi, J., Miyamoto, Y., Chan, J. R., Tanoue, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ErbB2+directly+activates+the+exchange+factor+Dock7+to+promote+Schwann+cell+migration.">ErbB2 directly activates the exchange factor Dock7 to promote Schwann cell migration.</a> The Journal of cell biology. 181 (2), 351-365 (2008).</li><li>Anton, E. S., Weskamp, G., Reichardt, L. F., Matthew, W. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nerve+growth+factor+and+its+low-affinity+receptor+promote+Schwann+cell+migration.">Nerve growth factor and its low-affinity receptor promote Schwann cell migration.</a> Proceedings of the National Academy of Sciences of the United States of America. 91 (7), 2795-2799 (1994).</li><li>Mahanthappa, N. K., Anton, E. S., Matthew, W. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glial+growth+factor+2,+a+soluble+neuregulin,+directly+increases+Schwann+cell+motility+and+indirectly+promotes+neurite+outgrowth.">Glial growth factor 2, a soluble neuregulin, directly increases Schwann cell motility and indirectly promotes neurite outgrowth.</a> The Journal of Neuroscience: The Official Journal of the Society for Neuroscience. 16 (15), 4673-4683 (1996).</li><li>Yamauchi, J., Chan, J. R., Shooter, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurotrophins+regulate+Schwann+cell+migration+by+activating+divergent+signaling+pathways+dependent+on+Rho+GTPases.">Neurotrophins regulate Schwann cell migration by activating divergent signaling pathways dependent on Rho GTPases.</a> Proceedings of the National Academy of Sciences of the United States of America. 101 (23), 8774-8779 (2004).</li><li>Gumy, L. F., Bampton, E. T. W., Tolkovsky, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyperglycaemia+inhibits+Schwann+cell+proliferation+and+migration+and+restricts+regeneration+of+axons+and+Schwann+cells+from+adult+murine+DRG.">Hyperglycaemia inhibits Schwann cell proliferation and migration and restricts regeneration of axons and Schwann cells from adult murine DRG.</a> Molecular and Cellular Neurosciences. 37 (2), 298-311 (2008).</li><li>Sakaue-Sawano, A., Kurokawa, H., Morimura, T., Hanyu, A., Hama, H., Osawa, H., Kashiwagi, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualizing+spatiotemporal+dynamics+of+multicellular+cell-cycle+progression.">Visualizing spatiotemporal dynamics of multicellular cell-cycle progression.</a> Cell. 132 (3), 487-498 (2008).</li><li>Park, D., Don, A. S., Massamiri, T., Karwa, A., Warner, B., MacDonald, J., Hemenway, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Noninvasive+imaging+of+cell+death+using+an+Hsp90+ligand.">Noninvasive imaging of cell death using an Hsp90 ligand.</a> Journal of the American Chemical Society. 133 (9), 2832-2835 (2011).</li><li>Shcherbo, D., Souslova, E. A., Goedhart, J., Chepurnykh, T. V., Gaintzeva, A., Shemiakina, I. I., Gadella, T. W. J., Lukyanov, S., Chudakov, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Practical+and+reliable+FRET/FLIM+pair+of+fluorescent+proteins.">Practical and reliable FRET/FLIM pair of fluorescent proteins.</a> BMC Biotechnology. 9, 24 (2009).</li></ol>

Não há conflitos de interesse declarados.

O desenvolvimento do sistema nervoso periférico é um processo excitante. Quando o desenvolvimento estiver concluído, os axônios são ensheathed por SCs ao longo de todo o comprimento, o qual pode, em humanos, ser muitas vezes mais de 100 cm. Para este fim, o número correcto de os SCs requeridas deve ser estabelecido durante o desenvolvimento e as SCs também tem que se mover ao longo de axónios estendem para a periferia para assegurar a cobertura completa axonal. Isso vale para mielinizadas, mas também para os ax...

<table border="1"><tbody><tr><td> Nome do reagente / Material </td><td> Companhia </td><td> Número de Catálogo </td><td> Comentários </td></tr><tr><td> MEM 10x </td><td> Gibco </td><td> 21430 </td><td></td></tr><tr><td> Bicarbonato de sódio (7,5%) </td><td> Gibco </td><td> 25080 </td><td></td></tr><tr><td> Glutamina </td><td> Gibco </td><td> 25030 </td><td></td></tr><tr><td> NaOH </td><td> Merck </td><td> 109137 </td><td></td></tr><tr><td> NGF </td><td> Roche </td><td> 1058231 </td><td> R &amp; D # 556-NG-100 </td></tr><tr><td> Meio Neurobasal </td><td> Gibco </td><td> 21103 </td><td></td></tr><tr><td> B27 Suplemento </td><td> Gibco </td><td> 17504 </td><td></td></tr><tr><td> antibióticos </td><td> Gibco </td><td> 15640 </td><td></td></tr><tr><td> d-PBS </td><td> Gibco </td><td> 14040 </td><td></td></tr><tr><td> agulhas de insetos </td><td> FST </td><td> 26002-20 </td><td></td></tr><tr><td> agulha da seringa </td><td> Braun </td><td></td><td> BD # 300013 </td></tr><tr><td> 8 slides câmara bem </td><td> Laboratório tek </td><td> 177402 </td><td></td></tr></tbody></table>

analyzing murine schwann cell development along growing axons

O desenvolvimento de nervos periféricos é um processo intrigante. Neurônios enviam axônios para inervar alvos específicos, que nos seres humanos muitas vezes são mais de 100 cm de distância da soma do neurônio. A sobrevivência neuronal durante o desenvolvimento depende de factores de crescimento derivados alvo, mas também com o apoio de células de Schwann (SC). Para este fim os axônios ensheath SC a partir da região da soma neuronal (ou a transição da central para o sistema nervoso periférico) para a sinapse ou junção neuromuscular. As células de Schwann são derivados da crista neural e migram ao longo de axónios como precursores emergentes até o axónio inteiro é coberto com SCs. Isto demonstra a importância do SC de migração para o desenvolvimento do sistema nervoso periférico e sublinha a necessidade de investigar este processo. A fim de analisar SC desenvolvimento, uma configuração é necessário que ao lado das SCs também inclui seu substrato fisiológico para a migração, o axônio. Devido ao desenvolvimento intra-uterino <em&gt; imagem in vivo com lapso de tempo, no entanto, não é viável em vertebrados placentários como camundongo (Mus musculus). Para contornar isso, adaptamos o gânglio cervical superior técnica de explante (SCG). Após tratamento com factor de crescimento do nervo (NGF) explantes SCG estendem axónios, seguido de precursores SC migram ao longo dos axónios do gânglio para a periferia. A beleza deste sistema é que o SC são derivados a partir de um pool de SC endógena e que migram ao longo das suas próprias axônios fisiológicos que estão a crescer, ao mesmo tempo. Este sistema é especialmente interessante, porque o desenvolvimento ao longo SC axónios podem ser analisados ​​por lapso de tempo de imagem, abrindo novas possibilidades para obter insights sobre migração SC.

Crescimento axonal é facilitada a partir de explantes de SCG, após tratamento com NGF (4) (esquema filme Figura 1 esquema de S1). Este processo é facilmente visível por um microscópio invertido e pode ser seguido por lapso de tempo de imagem (vídeo S2). Se um cientista é novo para dissecar SCG de embriões de camundongos recomendamos uma validação da técnica por um hidroxilase anti-tirosina simples (TH) imuno-histoquímica. TH é um marcador para neurónios catecolaminérgicos...

Watch this Scientific Journal Video about Analyzing Murine Schwann Cell Development Along Growing Axons at JoVE.com

Analyzing Murine Schwann Cell Development Along Growing Axons

Aqui descrevemos uma célula de Schwann (SC) ensaio de migração em que SCs são capazes de desenvolver ao longo dos axônios estendem.

Analisando o desenvolvimento de células de Schwann Murino Junto axônios em crescimento

The  development of peripheral nerves is an intriguing process. Neurons send out  axons to innervate specific targets, which in humans are often more than ...

analyzing-murine-schwann-cell-development-along-growing-axons

Research

JoVE Journal

Neuroscience

11.6K visualizações.  University of Freiburg. Aqui descrevemos uma célula de Schwann (SC) ensaio de migração em que SCs são capazes de desenvolver ao longo dos axônios estendem.

Vídeo: Analyzing Murine Schwann Cell Development Along Growing Axons

Live Imaging of Dorsal Root Axons after Rhizotomy

The primary sensory axons injured by spinal root injuries fail to regenerate into the spinal cord, leading to chronic pain and permanent sensory loss. Regeneration of dorsal root (DR) axons into spinal cord is prevented at the dorsal root entry zone (DREZ), the interface between the CNS and PNS. Our understanding of the molecular and cellular events that prevent regeneration at DREZ is incomplete, in part because complex changes associated with nerve injury have been deduced from postmortem analyses. Dynamic cellular processes, such as axon regeneration, are best studied with techniques that capture real-time events with multiple observations of each living animal. Our ability to monitor neurons serially in vivo has increased dramatically owing to revolutionary innovations in optics and mouse transgenics. Several lines of thy1-GFP transgenic mice, in which subsets of neurons are genetically labeled in distinct fluorescent colors, permit individual neurons to be imaged in vivo1. These mice have been used extensively for in vivo imaging of muscle2-4 and brain5-7, and have provided novel insights into physiological mechanisms that static analyses could not have resolved. Imaging studies of neurons in living spinal cord have only recently begun. Lichtman and his colleagues first demonstrated their feasibility by tracking injured dorsal column (DC) axons with wide-field microscopy8,9. Multi-photon in vivo imaging of deeply positioned DC axons, microglia and blood vessels has also been accomplished10. Over the last few years, we have pioneered in applying in vivo imaging to monitor regeneration of DR axons using wide-field microscopy and H line of thy1-YFP mice. These studies have led us to a novel hypothesis about why DR axons are prevented from regenerating within the spinal cord11.
In H line of thy1-YFP mice, distinct YFP+ axons are superficially positioned, which allows several axons to be monitored simultaneously. We have learned that DR axons arriving at DREZ are better imaged in lumbar than in cervical spinal cord. In the present report we describe several strategies that we have found useful to assure successful long-term and repeated imaging of regenerating DR axons. These include methods that eliminate repeated intubation and respiratory interruption, minimize surgery-associated stress and scar formation, and acquire stable images at high resolution without phototoxicity.

An in vivo imaging protocol to monitor primary sensory axons following dorsal root crush is described. The procedures utilize wide-field fluorescence microscopy and thy1-YFP transgenic mice, and permit repeated imaging of axon regeneration over 4 cm in the PNS and axon interactions with the interface of the CNS.

Imagens ao vivo de axônios da raiz dorsal após rizotomia

The primary sensory axons injured by spinal root injuries fail to regenerate into the spinal cord, leading to chronic pain and permanent sensory loss. ...

Neurociência

Single-cell Profiling of Developing and Mature Retinal Neurons

Highly specialized, but exceedingly small populations of cells play important roles in many tissues. The identification of cell-type specific markers and gene expression programs for extremely rare cell subsets has been a challenge using standard whole-tissue approaches. Gene expression profiling of individual cells allows for unprecedented access to cell types that comprise only a small percentage of the total tissue1-7. In addition, this technique can be used to examine the gene expression programs that are transiently expressed in small numbers of cells during dynamic developmental transitions8.
This issue of cellular diversity arises repeatedly in the central nervous system (CNS) where neuronal connections can occur between quite diverse cells9. The exact number of distinct cell types is not precisely known, but it has been estimated that there may be as many as 1000 different types in the cortex itself10. The function(s) of complex neural circuits may rely on some of the rare neuronal types and the genes they express. By identifying new markers and helping to molecularly classify different neurons, the single-cell approach is particularly useful in the analysis of cell types in the nervous system. It may also help to elucidate mechanisms of neural development by identifying differentially expressed genes and gene pathways during early stages of neuronal progenitor development.
As a simple, easily accessed tissue with considerable neuronal diversity, the vertebrate retina is an excellent model system for studying the processes of cellular development, neuronal differentiation and neuronal diversification. However, as in other parts of the CNS, this cellular diversity can present a problem for determining the genetic pathways that drive retinal progenitors to adopt a specific cell fate, especially given that rod photoreceptors make up the majority of the total retinal cell population11. Here we report a method for the identification of the transcripts expressed in single retinal cells (Figure 1). The single-cell profiling technique allows for the assessment of the amount of heterogeneity present within different cellular populations of the retina2,4,5,12. In addition, this method has revealed a host of new candidate genes that may play role(s) in the cell fate decision-making processes that occur in subsets of retinal progenitor cells8. With some simple adjustments to the protocol, this technique can be utilized for many different tissues and cell types.

A method for the isolation of single retinal cells and subsequent amplification of their cDNAs is described. Single-cell transcriptomics reveals the degree of cellular heterogeneity present in a tissue and uncovers new marker genes for rare cell populations. The accompanying protocol can be adjusted to suit many different cell types.

De uma única célula perfil de imaturos e maduros neurônios da retina

Highly specialized, but exceedingly small populations of cells play important roles in many tissues. The identification of cell-type specific markers and ...

Isolation and Culture of Neural Crest Cells from Embryonic Murine Neural Tube

The embryonic neural crest (NC) is a multipotent progenitor population that originates at the dorsal aspect of the neural tube, undergoes an epithelial to mesenchymal transition (EMT) and migrates throughout the embryo, giving rise to diverse cell types 1-3. NC also has the unique ability to influence the differentiation and maturation of target organs4-6. When explanted in vitro, NC progenitors undergo self-renewal, migrate and differentiate into a variety of tissue types including neurons, glia, smooth muscle cells, cartilage and bone. 
NC multipotency was first described from explants of the avian neural tube7-9. In vitro isolation of NC cells facilitates the study of NC dynamics including proliferation, migration, and multipotency. Further work in the avian and rat systems demonstrated that explanted NC cells retain their NC potential when transplanted back into the embryo10-13. Because these inherent cellular properties are preserved in explanted NC progenitors, the neural tube explant assay provides an attractive option for studying the NC in vitro. 
To attain a better understanding of the mammalian NC, many methods have been employed to isolate NC populations. NC-derived progenitors can be cultured from post-migratory locations in both the embryo and adult to study the dynamics of post-migratory NC progenitors11,14-20, however isolation of NC progenitors as they emigrate from the neural tube provides optimal preservation of NC cell potential and migratory properties13,21,22. Some protocols employ fluorescence activated cell sorting (FACS) to isolate a NC population enriched for particular progenitors11,13,14,17. However, when starting with early stage embryos, cell numbers adequate for analyses are difficult to obtain with FACS, complicating the isolation of early NC populations from individual embryos. Here, we describe an approach that does not rely on FACS and results in an approximately 96% pure NC population based on a Wnt1-Cre activated lineage reporter23. 
The method presented here is adapted from protocols optimized for the culture of rat NC11,13. The advantages of this protocol compared to previous methods are that 1) the cells are not grown on a feeder layer, 2) FACS is not required to obtain a relatively pure NC population, 3) premigratory NC cells are isolated and 4) results are easily quantified. Furthermore, this protocol can be used for isolation of NC from any mutant mouse model, facilitating the study of NC characteristics with different genetic manipulations. The limitation of this approach is that the NC is removed from the context of the embryo, which is known to influence the survival, migration and differentiation of the NC2,24-28.

Isolation of embryonic neural crest from the neural tube facilitates the use of in vitro methods for studying migration, self-renewal, and multipotency of neural crest.

Isolamento e cultivo de células da crista neural do tubo neural embrionário murino

The embryonic neural crest (NC) is a multipotent progenitor population that originates at the dorsal aspect of the neural tube, undergoes an epithelial to ...

A Quantitative Cell Migration Assay for Murine Enteric Neural Progenitors

Neural crest cells (NCC) are a transient and multipotent cell population that originates from the dorsal neural tube and migrates extensively throughout the developing vertebrate embryo. In addition to providing peripheral glia and neurons, NCC generate melanocytes as well as most of the cranio-facial skeleton. NCC migration and differentiation is controlled by a combination of their axial origin along the neural tube and their exposure to regionally distinct extracellular cues. Such contribution of extracellular ligands is especially evident during the formation of the enteric nervous system (ENS), a complex interconnected network of neural ganglia that locally controls (among other things) gut muscle movement and intestinal motility. Most of the ENS is derived from a small initial pool of NCC that undertake a long journey in order to colonize - in a rostral to caudal fashion - the entire length of the prospective gut. Among several signaling pathways known to influence enteric NCC colonization, GDNF/RET signaling is recognized as the most important. Indeed, spatiotemporally controlled secretion of the RET ligand GDNF by the gut mesenchyme is chiefly responsible for the attraction and guidance of RET-expressing enteric NCC to and within the embryonic gut. Here, we describe an ex vivo cell migration assay, making use of a transgenic mouse line possessing fluorescently labeled NCC, which allows precise quantification of enteric NCC migration potential in the presence of various growth factors, including GDNF.

We present an ex vivo cell migration assay that allows precise quantification of enteric neural crest cell migration potential in the presence of various growth factors.

Um ensaio de migração celular quantitativo para murinos progenitores neurais entéricas

Neural crest cells (NCC) are a transient and multipotent cell population that originates from the dorsal neural tube and migrates extensively throughout ...

Laser Nanosurgery of Cerebellar Axons In Vivo

Only a few neuronal populations in the central nervous system (CNS) of adult mammals show local regrowth upon dissection of their axon. In order to understand the mechanism that promotes neuronal regeneration, an in-depth analysis of the neuronal types that can remodel after injury is needed. Several studies showed that damaged climbing fibers are capable of regrowing also in adult animals1,2. The investigation of the time-lapse dynamics of degeneration and regeneration of these axons within their complex environment can be performed by time-lapse two-photon fluorescence (TPF) imaging in vivo3,4. This technique is here combined with laser surgery, which proved to be a highly selective tool to disrupt fluorescent structures in the intact mouse cortex5-9.
This protocol describes how to perform TPF time-lapse imaging and laser nanosurgery of single axonal branches in the cerebellum in vivo. Olivocerebellar neurons are labeled by anterograde tracing with a dextran-conjugated dye and then monitored by TPF imaging through a cranial window. The terminal portion of their axons are then dissected by irradiation with a Ti:Sapphire laser at high power. The degeneration and potential regrowth of the damaged neuron are monitored by TPF in vivo imaging during the days following the injury.

Laser Nanosurgery of Cerebellar Axons In Vivo

Two-photon imaging, coupled to laser nanodissection, are useful tools to study degenerative and regenerative processes in the central nervous system with subcellular resolution. This protocol shows how to label, image, and dissect single climbing fibers in the cerebellar cortex in vivo.

Laser Nanocirurgia de cerebelo axônios<em&gt; In Vivo</em

Only a few neuronal populations in the central nervous system (CNS) of adult mammals show local regrowth upon dissection of their axon. In order to ...

Live Imaging of Nicotine Induced Calcium Signaling and Neurotransmitter Release Along Ventral Hippocampal Axons

Sustained enhancement of axonal signaling and increased neurotransmitter release by the activation of pre-synaptic nicotinic acetylcholine receptors (nAChRs) is an important mechanism for neuromodulation by acetylcholine (ACh). The difficulty with access to probing the signaling mechanisms within intact axons and at nerve terminals both in vitro and in vivo has limited progress in the study of the pre-synaptic components of synaptic plasticity. Here we introduce a gene-chimeric preparation of ventral hippocampal (vHipp)&#8211;accumbens (nAcc) circuit in vitro that allows direct live imaging to analyze both the pre- and post-synaptic components of transmission while selectively varying the genetic profile of the pre- vs post-synaptic neurons. We demonstrate that projections from vHipp microslices, as pre-synaptic axonal input, form multiple, reliable glutamatergic synapses with post-synaptic targets, the dispersed neurons from nAcc. The pre-synaptic localization of various subtypes of nAChRs are detected and the pre-synaptic nicotinic signaling mediated synaptic transmission are monitored by concurrent electrophysiological recording and live cell imaging. This preparation also provides an informative approach to study the pre- and post-synaptic mechanisms of glutamatergic synaptic plasticity in vitro.

We developed a gene-chimeric preparation of ventral hippocampal &#8211; accumbens circuit in vitro that allows direct live imaging to analyze presynaptic mechanisms of nicotinic acetylcholine receptors (nAChRs) mediated synaptic transmission. This preparation also provides an informative approach to study the pre- and post-synaptic mechanisms of synaptic plasticity.

Imagens ao vivo de nicotina Induzida Sinalização de Cálcio e Neurotransmitter lançamento Junto ventrais do hipocampo Axons

Sustained enhancement of axonal signaling and increased neurotransmitter release by the activation of pre-synaptic nicotinic acetylcholine receptors ...

In Vivo Gene Transfer to Schwann Cells in the Rodent Sciatic Nerve by Electroporation

The formation of the myelin sheath by Schwann cells (SCs) is essential for rapid conduction of nerve impulses along axons in the peripheral nervous system. SC-selective genetic manipulation in living animals is a powerful technique for studying the molecular and cellular mechanisms of SC myelination and demyelination in vivo. While knockout/knockin and transgenic mice are powerful tools for studying SC biology, these methods are costly and time consuming. Viral vector-mediated transgene introduction into the sciatic nerve is a simpler and less laborious method. However, viral methods have limitations, such as toxicity, transgene size constraints, and infectivity restricted to certain developmental stages. Here, we describe a new method that allows selective transfection of myelinating SCs in the rodent sciatic nerve using electroporation. By applying electric pulses to the sciatic nerve at the site of plasmid DNA injection, genes of interest can be easily silenced or overexpressed in SCs in both neonatal and more mature animals. Furthermore, this in vivo electroporation method allows for highly efficient simultaneous expression of multiple transgenes. Our novel technique should enable researchers to efficiently manipulate SC gene expression, and facilitate studies on SC development and function.

In Vivo Gene Transfer to Schwann Cells in the Rodent Sciatic Nerve by Electroporation

Here, we present an in vivo technique for gene transfer to Schwann cells (SCs) in the rodent sciatic nerve. This simple technique is useful for investigating signaling mechanisms involved in the development and maintenance of myelinating SCs.

Em Gene Vivo Transferência de células de Schwann no nervo ciático de roedores por Eletroporação

The formation of the myelin sheath by Schwann cells (SCs) is essential for rapid conduction of nerve impulses along axons in the peripheral nervous ...

Using Linear Agarose Channels to Study Drosophila Larval Crawling Behavior

Drosophila larval crawling is emerging as a powerful model to study neural control of sensorimotor behavior. However, larval crawling behavior on flat open surfaces is complex,&#160;including: pausing, turning, and meandering. This complexity in the repertoire of movement hinders detailed analysis of the events occurring during a single crawl stride cycle. To overcome this obstacle, linear agarose channels were made that constrain larval behavior to straight, sustained, rhythmic crawling. In principle, because agarose channels and the Drosophila larval body are both optically clear, the movement of larval structures labeled by genetically-encoded fluorescent probes can be monitored in intact, freely-moving larvae. In the past, larvae were placed in linear channels and crawling at the level of whole organism, segment, and muscle were analyzed1. In the future, larvae crawling in channels can be used for calcium imaging to monitor neuronal activity. Moreover, these methods can be used with larvae of any genotype and with any researcher-designed channel. Thus the protocol presented below is widely applicable for studies using the Drosophila larva as a model to understand motor control.

Using Linear Agarose Channels to Study Drosophila Larval Crawling Behavior

The Drosophila larva is a powerful model system to study neural control of behavior. This publication describes the use of linear agarose channels to elicit sustained bouts of linear crawling and methods to quantify the dynamics of larval structures during repetitive crawling behavior.

Usando Canais Linear de agarose para o Estudo<em&gt; Drosophila</em&gt; Comportamento larval Crawling

Drosophila larval crawling is emerging as a powerful model to study neural control of sensorimotor behavior. However, larval crawling behavior on flat ...

Analyzing Dendritic Morphology in Columns and Layers

In many regions of the central nervous systems, such as the fly optic lobes and the vertebrate cortex, synaptic circuits are organized in layers and columns to facilitate brain wiring during development and information processing in developed animals. Postsynaptic neurons elaborate dendrites in type-specific patterns in specific layers to synapse with appropriate presynaptic terminals. The fly medulla neuropil is composed of 10 layers and about 750 columns; each column is innervated by dendrites of over 38 types of medulla neurons, which match with the axonal terminals of some 7 types of afferents in a type-specific fashion. This report details the procedures to image and analyze dendrites of medulla neurons. The workflow includes three sections: (i) the dual-view imaging section combines two confocal image stacks collected at orthogonal orientations into a high-resolution 3D image of dendrites; (ii) the dendrite tracing and registration section traces dendritic arbors in 3D and registers dendritic traces to the reference column array; (iii) the dendritic analysis section analyzes dendritic patterns with respect to columns and layers, including layer-specific termination and planar projection direction of dendritic arbors, and derives estimates of dendritic branching and termination frequencies. The protocols utilize custom plugins built on the open-source MIPAV (Medical Imaging Processing, Analysis, and Visualization) platform and custom toolboxes in the matrix laboratory language. Together, these protocols provide a complete workflow to analyze the dendritic routing of Drosophila medulla neurons in layers and columns, to identify cell types, and to determine defects in mutants.

Here, we show how to analyze dendritic routing of Drosophila medulla neurons in columns and layers. The workflow includes a dual-view imaging technique to improve the image quality and computational tools for tracing, registering dendritic arbors to the reference column array and for analyzing the dendritic structures in 3D space.

Analisando dendríticas Morfologia em Colunas e Camadas

In many regions of the central nervous systems, such as the fly optic lobes and the vertebrate cortex, synaptic circuits are organized in layers and ...

Spectral Reflectometric Microscopy on Myelinated Axons In Situ

In a mammalian nervous system, myelin provides an electrical insulation by enwrapping the axon fibers in a multilayered spiral. Inspired by its highly-organized subcellular architecture, we recently developed a new imaging modality, named spectral reflectometry (SpeRe), which enables unprecedented label-free nanoscale imaging of the live myelinated axons in situ. The underlying principle is to obtain nanostructural information by analyzing the reflectance spectrum of the multilayered subcellular structure. In this article, we describe a detailed step-by-step protocol for performing a basic SpeRe imaging of the nervous tissues using a commercial confocal microscopic system, equipped with a white-light laser and a tunable filter. We cover the procedures of sample preparation, acquisition of spectral data, and image processing for obtaining nanostructural information.

Spectral Reflectometric Microscopy on Myelinated Axons In Situ

Here, we present a step-by-step protocol for imaging myelinated axons in a fixed brain slice using a label-free nanoscale imaging technique based on spectral reflectometry.

Analisando o desenvolvimento de células de Schwann Murino Junto axônios em crescimento

Resumo

Explore mais vídeos

Capítulos neste vídeo