Riconosciamo K. Mikic, che ha contribuito alla fase iniziale di questo film e M. Nicolescu per l&#39;immagine miR. C. Huber è stato sostenuto da una borsa di studio del IZKF del Universtitätsklinikum Tübingen, A. Alwin Prem Anand dal programma fortuna del Universtitätsklinikum Tubinga.

1. Requisiti per In ovo Elettroporazione <ol><li> Preparazione del costrutto vettore: miR senso e antisenso primer sono stati progettati dopo le istruzioni del Ambion, ricotte e legato in ApaI / EcoRI digerito pSilencer U6.1 vettoriale. Dopo trasformazione di successo uno dei cloni risultanti stata coltivata e pSilencer plasmide è stato isolato mediante metodo di lisi alcalina utilizzando un kit di preparazione midi Quiagen. </li><li> Elettrodi: Gli elettrodi possono essere acquistati o facilmente essere costruite 13. Usiamo elettrodi self-made di filo di platino (Φ = 0.2, 0.25, o 0,5 millimetri di diametro) o in alcuni casi un ancora più piccolo elettrodo filo di tungsteno (Φ = 0.1 mm) 8, a seconda di quale area si vuole l&#39;elettroporazione. Per evitare scottature di tessuto, usiamo di norma il più vicino al tessuto del diluente elettrodi. Per un&#39;ampia elettroporazione di mesencefalo, usiamo 0,5 millimetri fili di platino saldati ad un tubolare in ottone / acciaio inoxalbero e fissato ad una porta elettrodi con una distanza di 3-5 mm (figura 1). Per l&#39;elettroporazione di aree specifiche, usiamo 0,25 millimetri anodi filo di platino e 0,2 millimetri filo di platino o 0,1 millimetri di tungsteno per il catodo con una distanza approssimativa di 1 mm o meno. </li><li> Soluzioni: hanno le seguenti soluzioni pronte: <ol><li> Ringer pollo autoclavato, pH 7.5 (9.0 g NaCl, 0,42 g KCl, CaCl2 0,24 g, sciogliere in 1 L di acqua distillata). </li><li> PBS (8 g NaCl, 0,2 g KCl, 0.24 g di KH 2 PO 4, 1,44 g di Na 2 HPO 4, sciogliere in 1l distillata H 2 O). </li><li> Veloce Verde: soluzione stock 10 mg / ml di H 2 O distillata </li><li> Inchiostro essiccazione lenta (meno gommalacca e quindi meno avvelenamento per l&#39;embrione). Nota: Un filtro dicroico blu collegata a una lampada a fibre ottiche come descritto nel canto-Soler e Adler 14 migliora il contrasto e può eliminare la necessità di iniettare inchiostro. </li></ol></li></ol><img src="/files/ftp_upload/50024/50024fig1.jpg" fo:content-width="6in" fo:src="/files/ftp_upload/50024/50024fig1highres.jpg"/> Figura 1. Schema di elettrodi e porta elettrodo. (A, B, C) ​​filo di platino è stato saldato su un lato di un albero tubolare in acciaio inox. Un foro è stato praticato nell&#39;altro lato dell&#39;albero tubolare così che le spine possono adattarsi in (A) rosso e fili di colore blu sono stati collegati alle spine. All&#39;estremità opposta il filo è stato montato connettori a banana che lavorano con le prese elettriche del electroporator. (A, C) Il filo di platino è stato piegato in un angelo di 90 °. Uno strato di smalto isolato dell&#39;albero sopra la piega. 2. Preparazioni direttamente prima in ovo Elettroporazione <ol><li> Preparare il seguente materiale: <ol><li> Diluire Ink con pollo Ringer 01:06, aggiungere la soluzione antibiotica-antimicotica (100x da Gibco) 1:100. </li><li> Preparare la soluzione di vettore: 1-2 mg / mL per DNA specifico in H 2 O integrato con verde veloce (1,20). </li><li> Sterilizzare pinze, forbici, ago di tungsteno e gli elettrodi con il 70% di etanolo. </li><li> Tirare micropipette per l&#39;iniezione di acido nucleico da capillari di vetro borosilicato (lunghezza e il diametro esterno: 100 mm x 0.9 mm). Usiamo un semplice estrattore PUL-1 (WPI, Berlino) con le impostazioni mostrate nella Tabella 1. </li><li> Impostare i parametri del electroporator come mostrato nella Tabella 2. </li></ol></li></ol><table border="1" ><tbody><tr><td fo:width="1in"> Parametri </td><td fo:width="1in"> Valori </td></tr><tr><td> Calore </td><td> 350 </td></tr><tr><td> Tirare </td><td> 100 </td></tr><tr><td> Velocità </td&gt; <td> 50 </td></tr><tr><td> Ritardo </td><td> 200 </td></tr></tbody></table> Tabella 1. Impostazioni per PUL-1 <table border="1"><tbody><tr><td fo:width="1.5in"> Parametri </td><td fo:width="1.5in"> Valori </td></tr><tr><td> Frequenza </td><td> 50 Hz </td></tr><tr><td> Ritardo </td><td> 20-50 msec * </td></tr><tr><td> Larghezza </td><td> 20 msec </td></tr><tr><td> Tensione </td><td> 8-25 V * </td></tr><tr><td> Impulso </td><td> 3 - 5 volte </td></tr><tr><td colspan="2"> * A seconda del diametro dell&#39;elettrodo e la distanza. Per favoretenerne conto quando si cambia uno dei parametri. </td></tr></tbody></table> Tabella 2. Impostazioni per lo stimolatore Pulse <ol start="2"><li> Preparare embrioni di pollo per l&#39;elettroporazione: <ol><li> Incubare uova di gallina fecondate dal loro lato più lungo a 37 ° C con 65% di umidità per 39 ore per acquisire embrioni tra Hamburger &amp; Hamilton (HH) mette in scena 15 9-11. L&#39;embrione si deposita nella parte più alta delle uova, così si dovrebbe segnare con un tratto di matita. </li><li> Disinfettare le uova con il 70% di etanolo. </li><li> Perforare l&#39;uovo al suo lato più ampio, in cui la cavità d&#39;aria dovrebbe essere. </li><li> Rimuovere 1-2 ml di bianco d&#39;uovo. Questo staccare l&#39;embrione dal guscio d&#39;uovo. </li><li> Cello-tape guscio d&#39;uovo per evitare scheggiature sul guscio di cui l&#39;embrione. Utilizzare un paio di forbici per tagliare una piccola finestra nel guscio attorno alla linea di matita. </li><li> Iniettare un po &#39;di inchiostrosotto la zona opaca per visualizzare l&#39;embrione. </li><li> Effettuare un taglio nella membrana vitellina con un ago di tungsteno affilato per ottenere una migliore accessibilità dell&#39;embrione iniettabile acido nucleico ed elettroporazione. </li></ol></li></ol> 3. Elettroporazione e incubazione <ol><li> Aggiungere poche gocce di soluzione calda di Ringer sulle embrioni. Questo abbasserà gli embrioni, evitare il surriscaldamento, attaccare degli elettrodi al tessuto e fornire un mezzo per la corrente tra i due elettrodi. </li><li> Iniettare il vettore soluzione nel lume del tubo neurale a livello del mesencefalo. Se l&#39;espressione del DNA vettore contiene alcun gene reporter (es. EGFP), aggiungere un vettore gene reporter leggermente inferiore concentrato (1 mg / mL miR esprimere vettore a 0,9 mg / mL gene reporter vector) alla soluzione di DNA. Questo farà sì che si riconoscono cellule transfettate dopo 8. Usiamo il cosiddetto vettore pCAX, un gentile dono from C. Krull 13. </li><li> Per un&#39;ampia trasfezione del mesencefalo, posizionare gli elettrodi sinistra e destra dell&#39;embrione all&#39;altezza del mesencefalo. La distanza tra gli elettrodi deve essere di circa 3-5 mm. Le altre impostazioni sono 15V, 20 impulsi msec e 50 msec di ritardo per HH 10. Modifica della posizione dei due elettrodi leggermente lungo la (DV) asse dorso-ventrale del mesencefalo assicura un più ampio trasfezione di cellule trasfezione asse DV. </li><li> Per la trasfezione ventrale, aggiungere qualche Ringer per sollevare la testa dalla membrana tuorlo e posizionare l&#39;anodo sotto mesencefalo ventrale. Se la testa non fanno spingere l&#39;elettrodo sotto la membrana che separa tuorlo e embrioni per evitare scottature del tubo neurale. Il catodo deve essere posto sopra il dorso lateralmente mesencefalo opposto verso l&#39;anodo. Non toccare il tubo neurale. Abbiamo transfettare la metà ventrale sinistro del mesencefalo per evitare difficoltà con lo sviluppo del cuore. La distanza tra gli elettrodiè di circa 1-0,5 mm, il resto delle impostazioni sono 10V, larghezza di 20 msec e 50 msec di ritardo. </li><li> Applicare un&#39;altra goccia di Saline sopra degli embrioni per raffreddarlo e rimuovere le bolle d&#39;aria. </li><li> Sigillare le uova con il nastro e incubare per almeno 4 ore, il tempo minimo richiesto per il vettore di espressione. </li></ol> 4. Fissazione di pollo embrioni <ol><li> Rimuovere gli embrioni dalle loro uova. </li><li> Embrioni Pulire sotto uno stereomicroscopio e valutare il grado di trasfezione con un microscopio a fluorescenza stereo. </li><li> Fissare gli embrioni per tutta la notte in PFA 4% a 4 ° C. Procedere con sezionamento e / o colorazione (ibridazione in situ, immunoistochimica) per analizzare i cambiamenti nella zona transfettate. </li></ol>

<ol>
	<li>Kutter, C., Svoboda, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=miRNA,+siRNA,+piRNA:+Knowns+of+the+unknown.">miRNA, siRNA, piRNA: Knowns of the unknown.</a> RNA Biol. 5, 181-188 (2008).</li><li>Szell, M., Bata-Csorgo, Z., Kemeny, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+enigmatic+world+of+mRNA-like+ncRNAs:+their+role+in+human+evolution+and+in+human+diseases.">The enigmatic world of mRNA-like ncRNAs: their role in human evolution and in human diseases.</a> Semin. Cancer Biol. 18, 141-148 (2008).</li><li>Li, X., Jin, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Roles+of+small+regulatory+RNAs+in+determining+neuronal+identity.">Roles of small regulatory RNAs in determining neuronal identity.</a> Nature reviews. Neuroscience. 11, 329-338 (2010).</li><li>Riedmann, L. T., Schwentner, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=miRNA,+siRNA,+piRNA+and+argonautes:+news+in+small+matters.">miRNA, siRNA, piRNA and argonautes: news in small matters.</a> RNA Biol. 7, 133-139 (2010).</li><li>Coolen, M., Bally-Cuif, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MicroRNAs+in+brain+development+and+physiology.">MicroRNAs in brain development and physiology.</a> Curr. Opin. Neurobiol. 19, 461-470 (2009).</li><li>Muramatsu, T., Mizutani, Y., Ohmori, Y., Okumura, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+three+nonviral+transfection+methods+for+foreign+gene+expression+in+early+chicken+embryos+in+ovo.">Comparison of three nonviral transfection methods for foreign gene expression in early chicken embryos in ovo.</a> Biochem. Biophys. Res. Commun. 230, 376-380 (1997).</li><li>Itasaki, N., Bel-Vialar, S., Krumlauf, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shocking'+developments+in+chick+embryology:+electroporation+and+in+ovo+gene+expression.">Shocking' developments in chick embryology: electroporation and in ovo gene expression.</a> Nat. Cell Biol. 1, 203-207 (1999).</li><li>Momose, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+targeting+of+gene+expression+in+chick+embryos+by+microelectroporation.">Efficient targeting of gene expression in chick embryos by microelectroporation.</a> Dev. Growth Differ. 41, 335-344 (1999).</li><li>Nakamura, H., Watanabe, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Misexpression+of+genes+in+brain+vesicles+by+in+ovo+electroporation.">Misexpression of genes in brain vesicles by in ovo electroporation.</a> Dev. Growth Differ. 42, 199-201 (2000).</li><li>Voiculescu, O., Papanayotou, C., Stern, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatially+and+temporally+controlled+electroporation+of+early+chick+embryos.">Spatially and temporally controlled electroporation of early chick embryos.</a> Nat. Protoc. 3, 419-426 (2008).</li><li>Neumann, E., Schaefer-Ridder, M., Wang, Y., Gene Hofschneider, P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=transfer+into+mouse+lyoma+cells+by+electroporation+in+high+electric+fields.">transfer into mouse lyoma cells by electroporation in high electric fields.</a> The EMBO journal. 1, 841-845 (1982).</li><li>Potter, H., Weir, L., Leder, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhancer-dependent+expression+of+human+kappa+immunoglobulin+genes+introduced+into+mouse+pre-B+lymphocytes+by+electroporation.">Enhancer-dependent expression of human kappa immunoglobulin genes introduced into mouse pre-B lymphocytes by electroporation.</a> Proceedings of the National Academy of Sciences of the United States of America. 81, 7161-7165 (1984).</li><li>Krull, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+primer+on+using+in+ovo+electroporation+to+analyze+gene+function.">A primer on using in ovo electroporation to analyze gene function.</a> Dev. Dyn. 229, 433-439 (2004).</li><li>Canto-Soler, M. V., Adler, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optic+cup+and+lens+development+requires+Pax6+expression+in+the+early+optic+vesicle+during+a+narrow+time+window.">Optic cup and lens development requires Pax6 expression in the early optic vesicle during a narrow time window.</a> Developmental biology. , 294-2119 (2006).</li><li>Hamburger, V., Hamilton, H. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+series+of+normal+stages+in+the+development+of+the+chick+embryo.+1951.">A series of normal stages in the development of the chick embryo. 1951.</a> Dev Dyn. 195, 231-272 (1992).</li><li>Muramatsu, T., Nakamura, A., Park, H. 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+electroporation:+a+powerful+and+convenient+means+of+nonviral+gene+transfer+to+tissues+of+living+animals+(Review).">In vivo electroporation: a powerful and convenient means of nonviral gene transfer to tissues of living animals (Review).</a> Int J Mol Med. 1, 55-62 (1998).</li><li>Agoston, Z., Li, N., Haslinger, A., Wizenmann, A., Schulte, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+and+physical+interaction+of+Meis2,+Pax3+and+Pax7+during+dorsal+midbrain+development.">Genetic and physical interaction of Meis2, Pax3 and Pax7 during dorsal midbrain development.</a> BMC Dev Biol. 12, 10 (2012).</li><li>De Pietri Tonelli, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-cell+detection+of+microRNAs+in+developing+vertebrate+embryos+after+acute+administration+of+a+dual-fluorescence+reporter/sensor+plasmid.">Single-cell detection of microRNAs in developing vertebrate embryos after acute administration of a dual-fluorescence reporter/sensor plasmid.</a> Biotechniques. 41, 727-732 (2006).</li></ol>

Non abbiamo nulla da rivelare.

Questo video mostra un metodo efficace per trasfettare plasmide nelle cellule neuroepiteliale di aree specifiche del mesencefalo pulcino. Impulsi elettrici rettangolari di bassa tensione possono introdurre DNA in cellule del tubo neurale pulcino in ovo 6,16. Tuttavia, la precisione di targeting DNA è spesso ostacolata dal campo elettrico ampia, che sale attraverso le relativamente grandi elettrodi (Φ = 0,5 mm). Abbiamo cercato di affrontare questo problema utilizzando elettrodi più piccoli di diam...

Il riconoscimento di piccoli RNA non codificanti come lettori aggiuntivi per l&#39;espressione genica ha lanciato una nuova complessità genomica regolamento programmazione / gene. Diverse specie di RNA non codificanti hanno importanza funzionale in cellule neurali, comprese le piccole non codificanti RNA 1-4. I microRNA (miR o miRNA), per esempio, mostrano profili di espressione distinti e mutevoli nel cervello in via di sviluppo 5. Mirata in elettroporazione ovo di embrioni di pollo offre un&#39;opportunità unica per il controllo spaziale e temporale di espressione genica e silenziamento durante lo sviluppo. Questo video mostra le varie fasi di esecuzione di espressione ectopica di miR in specifiche aree del mesencefalo pulcino utilizzo in ovo elettroporazione 6-10. Per garantire un effetto di lunga durata di questi piccoli RNA non codificanti nelle cellule, la sequenza di DNA di miR sono stati clonati in vettori mono o bi-cistronic. Perché in elettroporazione ovo, miR contenente vettore viene iniettato nel tubo neurale mesencefalo esponendo l&#39;embrione dopo aver effettuato una piccola finestra nel guscio dell&#39;uovo. Trasfezione aree specifiche del mesencefalo più piccola (anodo) e negativo (catodo) elettrodi di platino sono collocati in posizioni specifiche. Per ventrale trasfezione mesencefalo, l&#39;anodo si trova sotto il mesencefalo ventrale sinistro e il catodo sopra la metà destra del mesencefalo prima di applicare una corrente. L&#39;apertura nel guscio è chiusa con nastro e embrioni vengono incubati per tutto il tempo richiesto per ogni analisi. Questo metodo è stato originariamente descritto da Muramatsu et al. 6 e migliorata Momose et al. 8 per zona specifica trasfezione. <img src="/files/ftp_upload/50024/50024schematic1.jpg" fo:content-width-="6in" fo:src="/files/ftp_upload/50024/50024schematic1highres.jpg"/> Panoramica schematica. <ol><li> L&#39;embrione nell&#39;uovo è esposto tagliando una piccola finestra in the guscio d&#39;uovo. </li><li> Il vettore (s) disciolto viene iniettato nel mesencefalo usando un micro capillare. </li><li> Due elettrodi - disposti parallelamente o sotto e sopra l&#39;embrione - generano un campo elettrico pulsato. </li><li> Il campo elettrico crea temporalmente pori nella membrana cellulare, che facilitano l&#39;ingresso nella cellula dal DNA caricato negativamente (o RNA) attratti verso l&#39;anodo 11,12. </li></ol>

<table border="1">
<tbody>
 <tr>
 <td>Name </td>
 <td>Company</td>
 <td></td>
 <td>Model</td>
 </tr>
 <tr>
 <td>Borosillicate glass capillaries </td>
 <td>Hartenstein</td>
 <td></td>
 <td>Model: 0.9 mm</td>
 </tr>
 <tr>
 <td>Microcapillary puller</td>
 <td>WPI, Berlin</td>
 <td></td>
 <td>Model: Pul1-E</td>
 </tr>
 <tr>
 <td>Electroporator</td>
 <td>Intracel</td>
 <td></td>
 <td>Model: TSSIC</td>
 </tr>
 <tr>
 <td>Stereomicroscope - fluorescence </td>
 <td>LEICA</td>
 <td></td>
 <td>Model: MZFLIII</td>
 </tr>
 <tr>
 <td>Stereomicroscope</td>
 <td>Zeiss</td>
 <td></td>
 <td>Model: Stemi</td>
 </tr>
 <tr>
 <td>Camera and software</td>
 <td>Zeiss</td>
 <td></td>
 <td>Model: Axiocam MRc/ Axiovision Re. 4.8</td>
 </tr>
 </tbody>
</table>

in ovo expression of microrna in ventral chick midbrain

RNA non codificanti sono altri giocatori nella regolazione dell&#39;espressione genica. Mirata in elettroporazione ovo di settori specifici fornisce uno strumento unico per il controllo spaziale e temporale di espressione microRNA ectopica. Tuttavia, le strutture cerebrali ventrali come mesencefalo ventrale sono piuttosto difficili da raggiungere per eventuali manipolazioni. Qui, dimostriamo un modo efficiente per l&#39;elettroporazione di miRNA nel mesencefalo ventrale con elettrodi di platino sottili. Questo metodo offre un modo affidabile per trasfettare aree specifiche del mesencefalo e uno strumento utile per studi in vivo.

L&#39;estensione dell&#39;area mesencefalo trasfettate con miR è visibile attraverso l&#39;espressione di GFP da un vettore giornalista iniettato insieme al miR esprimendo vettore (Figura 2). Utilizzando elettrodi di platino con un diametro di 0,5 mm e collocato parallelamente all&#39;asse AP di porta mesencefalo normalmente alla trasfezione di una vasta area lungo la-DV e AP-asse, compresi hindbrain, mesencefalo e talvolta diencefalo (Figure 2A e B). Le dimensioni degli elettrodi risu...

Watch this Scientific Journal Video about In ovo Expression of MicroRNA in Ventral Chick Midbrain at JoVE.com

In ovo Expression of MicroRNA in Ventral Chick Midbrain

Espressione ectopica è una tecnica per chiarire il ruolo microRNA nello sviluppo del cervello. Tuttavia, il targeting aree specifiche utilizzando in elettroporazione ovo è impegnativo. Qui vi mostriamo un modo efficiente alle regioni mesencefalo ventrale e dorsale in modo selettivo l&#39;elettroporazione.

In Expression Ovo di MicroRNA in Ventrale Chick Mesencefalo

Non-coding RNAs are additional players in regulating gene expression. Targeted in ovo electroporation of specific areas provides a unique tool for spatial ...

in-ovo-expression-of-microrna-in-ventral-chick-midbrain

Research

JoVE Journal

Neuroscience

In ovo Expression of MicroRNA in Ventral Chick Midbrain

10.4K Views.  University of Tübingen.  Espressione ectopica è una tecnica per chiarire il ruolo microRNA nello sviluppo del cervello. Tuttavia, il targeting aree specifiche utilizzando in elettroporazione ovo è impegnativo. Qui vi mostriamo un modo efficiente alle regioni mesencefalo ventrale e dorsale in modo selettivo l'elettroporazione. 

Video: In ovo Expression of MicroRNA in Ventral Chick Midbrain

Organotypic Slice Cultures of Embryonic Ventral Midbrain: A System to Study Dopaminergic Neuronal Development in vitro

The mouse is an excellent model organism to study mammalian brain development due to the abundance of molecular and genetic data. However, the developing mouse brain is not suitable for easy manipulation and imaging in vivo since the mouse embryo is inaccessible and opaque. Organotypic slice cultures of embryonic brains are therefore widely used to study murine brain development in vitro. Ex-vivo manipulation or the use of transgenic mice allows the modification of gene expression so that subpopulations of neuronal or glial cells can be labeled with fluorescent proteins. The behavior of labeled cells can then be observed using time-lapse imaging. Time-lapse imaging has been particularly successful for studying cell behaviors that underlie the development of the cerebral cortex at late embryonic stages 1-2. Embryonic organotypic slice culture systems in brain regions outside of the forebrain are less well established. Therefore, the wealth of time-lapse imaging data describing neuronal cell migration is restricted to the forebrain 3,4. It is still not known, whether the principles discovered for the dorsal brain hold true for ventral brain areas. In the ventral brain, neurons are organized in neuronal clusters rather than layers and they often have to undergo complicated migratory trajectories to reach their final position. The ventral midbrain is not only a good model system for ventral brain development, but also contains neuronal populations such as dopaminergic neurons that are relevant in disease processes. While the function and degeneration of dopaminergic neurons has been investigated in great detail in the adult and ageing brain, little is known about the behavior of these neurons during their differentiation and migration phase 5. We describe here the generation of slice cultures from the embryonic day (E) 12.5 mouse ventral midbrain. These slice cultures are potentially suitable for monitoring dopaminergic neuron development over several days in vitro. We highlight the critical steps in generating brain slices at these early stages of embryonic development and discuss the conditions necessary for maintaining normal development of dopaminergic neurons in vitro. We also present results from time lapse imaging experiments. In these experiments, ventral midbrain precursors (including dopaminergic precursors) and their descendants were labeled in a mosaic manner using a Cre/loxP based inducible fate mapping system 6.

Organotypic Slice Cultures of Embryonic Ventral Midbrain: A System to Study Dopaminergic Neuronal Development in vitro

A method to generate organotypic slices from the E12.5 murine embryonic midbrain is described. The organotypic slice cultures can be used to observe the behavior of dopaminergic neurons or other ventral midbrain neurons.

Culture Slice organotipica del mesencefalo ventrale embrionali: un sistema per studiare dopaminergici sviluppo neuronale In vitro</em

The  mouse is an excellent model organism to study mammalian brain development due  to the abundance of molecular and genetic data. However, the ...

Ricerca

Neuroscienze

High-resolution Live Imaging of Cell Behavior in the Developing Neuroepithelium

The embryonic spinal cord consists of cycling neural progenitor cells that give rise to a large percentage of the neuronal and glial cells of the central nervous system (CNS). Although much is known about the molecular mechanisms that pattern the spinal cord and elicit neuronal differentiation1, 2, we lack a deep understanding of these early events at the level of cell behavior. It is thus critical to study the behavior of neural progenitors in real time as they undergo neurogenesis.
In the past, real-time imaging of early embryonic tissue has been limited by cell/tissue viability in culture as well as the phototoxic effects of fluorescent imaging. Here we present a novel assay for imaging such tissue for long periods of time, utilizing a novel ex vivo slice culture protocol and wide-field fluorescence microscopy (Fig. 1). This approach achieves long-term time-lapse monitoring of chick embryonic spinal cord progenitor cells with high spatial and temporal resolution.
This assay may be modified to image a range of embryonic tissues3, 4 In addition to the observation of cellular and sub-cellular behaviors, the development of novel and highly sensitive reporters for gene activity (for example, Notch signaling5) makes this assay a powerful tool with which to understand how signaling regulates cell behavior during embryonic development.

Imaging embryonic tissue in real-time is challenging over long periods of time. Here we present an assay for monitoring cellular and sub-cellular changes in chick spinal cord for long periods with high spatial and temporal resolution. This technique can be adapted for other regions of the nervous system and developing embryo.

Imaging ad alta risoluzione dal vivo del comportamento delle cellule in via di sviluppo neuroepitelio

The embryonic spinal cord consists of cycling neural progenitor cells that give rise to a large percentage of the neuronal and glial cells of the central ...

In ovo Electroporation in Chick Midbrain for Studying Gene Function in Dopaminergic Neuron Development

Dopaminergic neurons located in the ventral midbrain control movement, emotional behavior, and reward mechanisms1-3. The dysfunction of ventral midbrain dopaminergic neurons is implicated in Parkinson's disease, Schizophrenia, depression, and dementia1-5. Thus, studying the regulation of midbrain dopaminergic neuron differentiation could not only provide important insight into mechanisms regulating midbrain development and neural progenitor fate specification, but also help develop new therapeutic strategies for treating a variety of human neurological disorders.
Dopaminergic neurons differentiate from neural progenitors lining the ventricular zone of embryonic ventral midbrain. The development of neural progenitors is controlled by gene expression programs6,7. Here we report techniques utilizing electroporation to express genes specifically in the midbrain of Hamburger Hamilton (HH) stage 11 (thirteen somites, 42 hours) chick embryos8,9. The external development of chick embryos allows for convenient experimental manipulations at specific embryonic stages, with the effects determined at later developmental time points10-13. Chick embryonic neural tubes earlier than HH stage 13 (nineteen somites, 48 hours) consist of multipotent neural progenitors that are capable of differentiating into distinct cell types of the nervous system. The pCAG vector, which contains both a CMV promoter and a chick &beta;-actin enhancer, allows for robust expression of Flag or other epitope-tagged constructs in embryonic chick neural tubes14. In this report, we emphasize special measures to achieve regionally restricted gene expression in embryonic midbrain dopaminergic neuron progenitors, including how to inject DNA constructs specifically into the embryonic midbrain region and how to pinpoint electroporation with small custom-made electrodes. Analyzing chick midbrain at later stages provides an excellent in vivo system for plasmid vector-mediated gain-of-function and loss-of-function studies of midbrain development. Modification of the experimental system may extend the assay to other parts of the nervous system for performing fate mapping analysis and for investigating the regulation of gene expression.

In ovo Electroporation in Chick Midbrain for Studying Gene Function in Dopaminergic Neuron Development

To assess the function and the regulation of genes during the development of midbrain dopaminergic neurons, we describe a method that involves in ovo electroporation of plasmid DNA constructs into embryonic chick ventral midbrain dopaminergic neuron progenitors. This technique can be used to achieve efficient expression of genes of interest to study different aspects of midbrain development and dopaminergic neuron differentiation.

In elettroporazione ovo nel mesencefalo Chick per lo Studio la funzione dei geni nello sviluppo dopaminergici Neuron

Dopaminergic neurons located in the ventral midbrain control movement, emotional behavior, and reward mechanisms1-3. The dysfunction of ventral midbrain ...

Comprehensive Profiling of Dopamine Regulation in Substantia Nigra and Ventral Tegmental Area

Dopamine is a vigorously studied neurotransmitter in the CNS. Indeed, its involvement in locomotor activity and reward-related behaviour has fostered five decades of inquiry into the molecular deficiencies associated with dopamine regulation. The majority of these inquiries of dopamine regulation in the brain focus upon the molecular basis for its regulation in the terminal field regions of the nigrostriatal and mesoaccumbens pathways; striatum and nucleus accumbens. Furthermore, such studies have concentrated on analysis of dopamine tissue content with normalization to only wet tissue weight. Investigation of the proteins that regulate dopamine, such as tyrosine hydroxylase (TH) protein, TH phosphorylation, dopamine transporter (DAT), and vesicular monoamine transporter 2 (VMAT2) protein often do not include analysis of dopamine tissue content in the same sample. The ability to analyze both dopamine tissue content and its regulating proteins (including post-translational modifications) not only gives inherent power to interpreting the relationship of dopamine with the protein level and function of TH, DAT, or VMAT2, but also extends sample economy. This translates into less cost, and yet produces insights into the molecular regulation of dopamine in virtually any paradigm of the investigators' choice.
We focus the analyses in the midbrain. Although the SN and VTA are typically neglected in most studies of dopamine regulation, these nuclei are easily dissected with practice. A comprehensive readout of dopamine tissue content and TH, DAT, or VMAT2 can be conducted. There is burgeoning literature on the impact of dopamine function in the SN and VTA on behavior, and the impingements of exogenous substances or disease processes therein 1-5. Furthermore, compounds such as growth factors have a profound effect on dopamine and dopamine-regulating proteins, to a comparatively greater extent in the SN or VTA 6-8. Therefore, this methodology is presented for reference to laboratories that want to extend their inquiries on how specific treatments modulate behaviour and dopamine regulation. Here, a multi-step method is presented for the analyses of dopamine tissue content, the protein levels of TH, DAT, or VMAT2, and TH phosphorylation from the substantia nigra and VTA from rodent midbrain. The analysis of TH phosphorylation can yield significant insights into not only how TH activity is regulated, but also the signaling cascades affected in the somatodendritic nuclei in a given paradigm.
We will illustrate the dissection technique to segregate these two nuclei and the sample processing of dissected tissue that produces a profile revealing molecular mechanisms of dopamine regulation in vivo, specific for each nuclei (Figure 1).

Dopamine is distinctly regulated in the midbrain nuclei, which contain the cell bodies and dendrites of the dopamine neurons. Here we describe a dissection and sample-handling approach to maximize results, and thus conclusions and insights, on dopamine regulation in the midbrain nuclei of the substantia nigra (SN) and ventral tegmental area (VTA) in rodents.

Profiling completa del regolamento dopamina nel substantia nigra e ventrale tegmentale Area

Dopamine is a vigorously studied neurotransmitter in the CNS. Indeed, its involvement in locomotor activity and reward-related behaviour has fostered five ...

Dual Electrophysiological Recordings of Synaptically-evoked Astroglial and Neuronal Responses in Acute Hippocampal Slices

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs through activation of their ion channels and neurotransmitter receptors, and process information in part through activity-dependent release of gliotransmitters. Furthermore, astrocytes constitute the main uptake system for glutamate, contribute to potassium spatial buffering, as well as to GABA clearance. These cells therefore constantly monitor synaptic activity, and are thereby sensitive indicators for alterations in synaptically-released glutamate, GABA and extracellular potassium levels. Additionally, alterations in astroglial uptake activity or buffering capacity can have severe effects on neuronal functions, and might be overlooked when characterizing physiopathological situations or knockout mice. Dual recording of neuronal and astroglial activities is therefore an important method to study alterations in synaptic strength associated to concomitant changes in astroglial uptake and buffering capacities. Here we describe how to prepare hippocampal slices, how to identify stratum radiatum astrocytes, and how to record simultaneously neuronal and astroglial electrophysiological responses. Furthermore, we describe how to isolate pharmacologically the synaptically-evoked astroglial currents.

The preparation of acute brain slices from isolated hippocampi, as well as the simultaneous electrophysiological recordings of astrocytes and neurons in stratum radiatum during stimulation of schaffer collaterals is described. The pharmacological isolation of astroglial potassium and glutamate transporter currents is demonstrated.

Due registrazioni elettrofisiologiche di sinapticamente-evocati Risposte astrogliale e neuronale in acute fettine di ippocampo

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs ...

RNA-Seq Analysis of Differential Gene Expression in Electroporated Chick Embryonic Spinal Cord

In ovo electroporation of the chick neural tube is a fast and inexpensive method for identification of gene function during neural development. Genome wide analysis of differentially expressed transcripts after such an experimental manipulation has the potential to uncover an almost complete picture of the downstream effects caused by the transfected construct. This work describes a simple method for comparing transcriptomes from samples of transfected embryonic spinal cords comprising all steps between electroporation and identification of differentially expressed transcripts. The first stage consists of guidelines for electroporation and instructions for dissection of transfected spinal cord halves from HH23 embryos in ribonuclease-free environment and extraction of high-quality RNA samples suitable for transcriptome sequencing. The next stage is that of bioinformatic analysis with general guidelines for filtering and comparison of RNA-Seq datasets in the Galaxy public server, which eliminates the need of a local computational structure for small to medium scale experiments. The representative results show that the dissection methods generate high quality RNA samples and that the transcriptomes obtained from two control samples are essentially the same, an important requirement for detection of differential expression genes in experimental samples. Furthermore, one example is provided where experimental overexpression of a DNA construct can be visually verified after comparison with control samples. The application of this method may be a powerful tool to facilitate new discoveries on the function of neural factors involved in spinal cord early development.

This video shows the basic steps for performing whole transcriptome analysis on dissected chick embryonic spinal cord samples after transfection with in ovo electroporation.

RNA-Seq Analisi di espressione genica differenziale in elettroporate Chick embrionali del midollo spinale

In ovo electroporation of the chick neural tube is a fast and inexpensive method for identification of gene function during neural development. Genome ...

Environmental Modulations of the Number of Midbrain Dopamine Neurons in Adult Mice

Long-lasting changes in the brain or &#8216;brain plasticity&#8217; underlie adaptive behavior and brain repair following disease or injury. Furthermore, interactions with our environment can induce brain plasticity. Increasingly, research is trying to identify which environments stimulate brain plasticity beneficial for treating brain and behavioral disorders. Two environmental manipulations are described which increase or decrease the number of tyrosine hydroxylase immunopositive (TH+, the rate-limiting enzyme in dopamine (DA) synthesis) neurons in the adult mouse midbrain. The first comprises pairing male and female mice together continuously for 1 week, which increases midbrain TH+ neurons by approximately 12% in males, but decreases midbrain TH+ neurons by approximately 12% in females. The second comprises housing mice continuously for 2 weeks in &#8216;enriched environments&#8217; (EE) containing running wheels, toys, ropes, nesting material, etc., which increases midbrain TH+ neurons by approximately 14% in males. Additionally, a protocol is described for concurrently infusing drugs directly into the midbrain during these environmental manipulations to help identify mechanisms underlying environmentally-induced brain plasticity. For example, EE-induction of more midbrain TH+ neurons is abolished by concurrent blockade of synaptic input onto midbrain neurons. Together, these data indicate that information about the environment is relayed via synaptic input to midbrain neurons to switch on or off expression of &#8216;DA&#8217; genes. Thus, appropriate environmental stimulation, or drug targeting of the underlying mechanisms, might be helpful for treating brain and behavioral disorders associated with imbalances in midbrain DA (e.g. Parkinson&#8217;s disease, attention deficit and hyperactivity disorder, schizophrenia, and drug addiction).

This protocol describes two different environmental manipulations and a concurrent brain infusion protocol to study environmentally-induced brain changes underlying adaptive behavior and brain repair in adult mice.

Modulazioni ambientali del numero di Mesencefalo dopamina neuroni in topi adulti

Long-lasting changes in the brain or &#8216;brain plasticity&#8217; underlie adaptive behavior and brain repair following disease or injury. Furthermore, ...

Reliable Identification of Living Dopaminergic Neurons in Midbrain Cultures Using RNA Sequencing and TH-promoter-driven eGFP Expression

In Parkinson&#39;s Disease (PD) there is widespread neuronal loss throughout the brain with pronounced degeneration of dopaminergic neurons in the SNc, leading to bradykinesia, rigidity, and tremor. The identification of living dopaminergic neurons in primary Ventral Mesencephalic (VM) cultures using a fluorescent marker provides an alternative way to study the selective vulnerability of these neurons without relying on the immunostaining of fixed cells. Here, we isolate, dissociate, and culture mouse VM neurons for 3 weeks. We then identify dopaminergic neurons in the cultures using eGFP fluorescence (driven by a Tyrosine Hydroxylase (TH) promoter). Individual neurons are harvested into microcentrifuge tubes using glass micropipettes. Next, we lyse the harvested cells, and conduct cDNA synthesis and transposon-mediated &#34;tagmentation&#34; to produce single cell RNA-Seq libraries1,2,3,4,5. After passing a quality-control check, single-cell libraries are sequenced and subsequent analysis is carried out to measure gene expression. We report transcriptome results for individual dopaminergic and GABAergic neurons isolated from midbrain cultures. We report that 100% of the live TH-eGFP cells that were harvested and sequenced were dopaminergic neurons. These techniques will have widespread applications in neuroscience and molecular biology.

In Parkinson&#39;s Disease (PD), Substantia Nigra (SNc) dopaminergic neurons degenerate, leading to motor dysfunction. Here we report a protocol for culturing ventral midbrain neurons from a mouse expressing eGFP driven by a Tyrosine Hydroxylase (TH) promoter sequence, harvesting individual fluorescent neurons from the cultures, and measuring their transcriptome using RNA-seq.

Identificazione affidabile di vita neuroni dopaminergici in Culture Midbrain Utilizzando RNA Sequencing e TH-promotore-driven eGFP Expression

In Parkinson&#39;s Disease (PD) there is widespread neuronal loss throughout the brain with pronounced degeneration of dopaminergic neurons in the SNc, ...

An In Ovo Model for Testing Insulin-mimetic Compounds

Elevated blood glucose levels in type 2 diabetes mellitus (T2DM), a complex and multifactorial metabolic disease, are caused by insulin resistance and &#946;-cell failure. Various strategies, including the injection of insulin or the usage of insulin-sensitizing drugs, were pursued to treat T2DM or at least reduce the symptoms. In addition, the application of herbal compounds has attracted increasing attention. Thus, it is necessary to find efficient test systems to identify and characterize insulin-mimetic compounds. Here we developed a modified chick embryo model, which enables testing of synthetic compounds and herbal extracts with insulin-mimetic properties. Using a fluorescence microscopy-based primary screen, which quantifies the translocation of Glucose transporter 4 (Glut4) to the plasma membrane, we were able to identify compounds, mainly herbal extracts, which lead to an increase of intracellular glucose concentrations in adipocytes. However, the efficacy of these substances requires further verification in a living organism. Thus, we used an in-ovo approach to identify their blood glucose-reducing properties. The approval by an ethics committee is not needed since the use of chicken embryos during the first two-thirds of embryonic development is not considered an animal experiment. Here, the application of this model is described in detail.

An In Ovo Model for Testing Insulin-mimetic Compounds

In this study, we describe an in-ovo system as a promising tool to test insulin-mimetic compounds in a living organism. The main advantages include adequate throughput rates and acceptable costs, which enable the identification of phytochemicals with insulin-mimetic properties.

Un modello In Ovo per testare composti insulino-mimetici

Elevated blood glucose levels in type 2 diabetes mellitus (T2DM), a complex and multifactorial metabolic disease, are caused by insulin resistance and ...

Combined In Vivo Anatomical and Functional Tracing of Ventral Tegmental Area Glutamate Terminals in the Hippocampus

Optogenetic modulation of neuron sub-populations in the brain has allowed researchers to dissect neural circuits in vivo and ex vivo. This provides a premise for determining the role of neuron types within a neural circuit, and their significance in information encoding relative to learning. Likewise, the method can be used to test the physiological significance of two or more connected brain regions in awake and anesthetized animals. The current study demonstrates how VTA glutamate neurons modulate the firing rate of putative pyramidal neurons in the CA1 (hippocampus) of anesthetized mice. This protocol employs adeno-associated virus (AAV)-dependent labeling of VTA glutamate neurons for the tracing of VTA presynaptic glutamate terminals in the layers of the hippocampus. Expression of light-controlled opsin (channelrhodopsin; hChR2) and fluorescence protein (eYFP) harbored by the AAV vector permitted anterograde tracing of VTA glutamate terminals, and photostimulation of VTA glutamate neuron cell bodies (in the VTA). High-impedance acute silicon electrodes were positioned in the CA1 to detect multi-unit and single-unit responses to VTA photostimulation in vivo. The results of this study demonstrate the&#160;layer-dependent distribution of presynaptic VTA glutamate terminals in the hippocampus (CA1, CA3, and DG). Also, the photostimulation of VTA glutamate neurons increased the firing and burst rate of putative CA1 pyramidal units in vivo.

The current protocol demonstrates a simple method for tracing of ventral tegmental area (VTA) glutamate projections to the hippocampus. Photostimulation of VTA glutamate neurons was combined with CA1 recording to demonstrate how VTA glutamate terminals modulate CA1 putative pyramidal firing rate in vivo.

Tracciato anatomico e funzionale combinato in vivo dei terminali del glutammato dell'area tegmentale ventrale nell'ippocampo

Optogenetic modulation of neuron sub-populations in the brain has allowed researchers to dissect neural circuits in vivo and ex vivo. This provides a ...

Methods Article

In Expression Ovo di MicroRNA in Ventrale Chick Mesencefalo