Name: efficient gene transfer in chick retinas for primary cell culture studies: an ex-ovo electroporation approach
Uploaded: 2015-11-02T14:00:00.000+00:00
Duration: 8 min 59 s
Description: Watch this Scientific Journal Video about Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach at JoVE.com

We would like to acknowledge David O'Brien for his support with data analysis, and all the members of the Canto-Soler lab for their critical discussions. This work was supported by NIH grants EY004859 and EY022631 (MVCS), Core Grant EY1765, and an unrestricted departmental grant from Research to Prevent Blindness, Inc.

Tutte le procedure descritte in questo lavoro sono stati eseguiti secondo le linee guida raccomandate dalla cura degli animali e del Comitato uso presso la Johns Hopkins University. 1. Ahead of Time: preparazione di strumenti, reagenti e piatti <ol><li> Preparazione di uova: incubare fecondate uova di gallina bianca Livorno a 37,5 ° C e 60% di umidità relativa per 5 giorni in una incubatrice uovo. NOTA: Un incubatore con capacità di oscillazione può essere utile per la standardizzazione e la sincronizzazione di sviluppo embrionale, ma a dondolo non è strettamente necessario per l&#39;esito di questo protocollo. </li><li> Plasmidi Preparazione: <ol><li> Disegno plasmide per costruire sovraespressione o downregulation gene (ad esempio tramite l&#39;uso della tecnologia RNAi 1,34) come necessario. Includere un gene reporter (come EGFP, RFP o LacZ) nel costrutto, quando possibile. NOTA: Alcuni promotori di uso comune come CMV, possono diventare a tacere dopo il tempo. Il promot CAGer (pollo beta-actina promotore con CMV enhancer) è una buona alternativa, fornendo espressione efficiente a lungo termine del gene di interesse 35-37. </li><li> Preparare una soluzione plasmide ad una concentrazione di 1,5 mg / mL in PBS sterile. OPTIONAL: Preparare la soluzione plasmide prima del tempo e conservarlo congelato fino al momento dell&#39;uso. NOTA: maggiore concentrazione plasmide non comportino un aumento significativo dell&#39;efficienza, mentre l&#39;uso di concentrazioni plasmide più basse riducono l&#39;efficienza di trasfezione 1. </li></ol></li><li> Elettrodi: <ol><li> Per l&#39;uso anodo un oro spessa punta elettrodo (vedi Tabella di materiali specifici / Equipment). Pulire con il 70% di etanolo. NOTA: Isolamento dell&#39;oro punta dell&#39;elettrodo, lasciando circa 0,5 mm a vista, è consigliabile per ridurre la dispersione della corrente elettrica. Informazioni per materiale isolante può essere trovato nella tabella di materiali specifici. </li><li> Fare un catodo di 2,5 mm quadrati bbue filamento, largo 4,5 mm (normalmente utilizzato in estrattori micropipetta). Con l&#39;aiuto di una pinza, svitare la scatola quadrata e raddrizzare filamento in una lunga striscia. Poi, al microscopio dissezione e utilizzando un righello come guida, piegare il filamento in una forma quadrata &#39;U&#39; lunga 3 mm alla base e 2 mm su un lato, con l&#39;altro lato della lunghezza rimanente del filamento (Figura 1 , C - D). Utilizzando pinze, immergere l&#39;elettrodo nel 96% di etanolo e fiamme al sterilizzare. Quindi collegare un cavo elettrico con un piccolo coccodrillo per il braccio più lungo dell&#39;elettrodo. </li></ol></li><li> Elettroporazione Camera Setup: <ol><li> Preparare la camera di elettroporazione tagliando il coperchio di una provetta sterile da 1,5 ml e apposizione, lato piatto verso il basso, ad una piastra di Petri 100 mm usando nastro (Figura 1E). NOTA: altro contenitore in forma di un pozzo di dimensioni simili funzionerebbe; tuttavia, un coperchio provetta è facilmente accessibile e autoclavabile. Il pozzodeve essere sufficiente per ospitare un elettrodo pulcino occhio e catodo grande, ma non così grande da risultare in una perdita di soluzione plasmide. </li></ol></li></ol> 2. Ex ovo Elettroporazione Procedura <ol><li> Preparazione degli strumenti: <ol><li> Sterilizzare gli strumenti di micro-dissezione (2 coppie di grandi pinze Moloney curve per aprire i gusci d&#39;uovo e scavando embrioni, 2 paia di fine-tip curvo pinzette Dumont per la rimozione di RPE, un paio di Bonn dentato forcipe per obiettivo la rimozione e vitreo) per immersione il punte in 96% di etanolo e fiammeggiante. Ambito dissezione Pulire con panni immersi nel 70% di etanolo. Scaldare una bottiglia di soluzione salina bilanciata sterile calcio-magnesio-libero di Hank (CMF-HBSS) in un bagno d&#39;acqua a 37 ° C. Riempire 100 mm sterili piastre Petri a 3/4 con caldo CMF-HBSS. </li><li> Mettere camera di elettroporazione con un altro microscopio dissezione pulito e riempire con 120 ml di soluzione di plasmide. Collegare gli elettrodi agli apparecchi elettroporazione, rendendoAssicurarsi elettrodo misura è collegato al polo negativo e oro punta dell&#39;elettrodo al polo positivo. </li></ol></li><li> Embrione Collezione: <ol><li> Pulire le uova strofinando conchiglie con salviette bagnate nel 70% di etanolo. Mantenere la procedura sterile per tutto il resto del protocollo per evitare di portare la contaminazione nelle culture. Utilizzando grandi pinze Moloney curve aprire con attenzione un buco nel guscio d&#39;uovo picchiettando delicatamente sulla punta arrotondata di un uovo (sopra la camera d&#39;aria) e poi presa e tirando fuori pezzi di conchiglia. </li><li> Con un altro paio di pinze rimuovere membrane e raccogliere embrione da scavare fuori l&#39;uovo (facendo attenzione a non danneggiare l&#39;embrione). Mettere in un piatto con CMF-HBSS. NOTA: raccogliere il maggior numero di embrioni necessari per ottenere il numero desiderato di tazze retina per elettroporazione come specificato in 2.4.4 </li><li> PUNTO CRITICO: stage gli embrioni secondo Hamburger e Hamilton 38. NOTA: Per ottenere gli embrioni ottimali di efficienzadeve essere di fase 27 (Figura 2A). </li><li> Eutanasia gli embrioni di decapitazione con pinze Moloney. </li></ol></li><li> Ottenere Coppe retina: <ol><li> Usando sottili pinzette Dumont, enucleare con attenzione gli occhi e trasferimento in un nuovo piatto CMF-HBSS. </li><li> Partendo dalla parte posteriore di ciascun occhio, in prossimità della testa del nervo ottico, e utilizzando due pinzette Dumont fine, introdurre una punta di ciascuna coppia di pinzette tra la retina neurale e RPE e accuratamente sezionare la RPE essendo cauto per non danneggiare neurale retina (Figura 2B). NOTA: La mancanza di Ca 2+ e Mg 2+ nella soluzione aiuterà il RPE stacca dalla retina neurale più facilmente. </li></ol></li><li> Elettroporazione: <ol><li> Impostare i parametri di elettroporatore per fornire impulsi di 5 quadrati di 15 volt, 50 msec, durata e intervallo 950 msec. Luogo &#39;U&#39; a forma di elettrodo negativo all&#39;interno della camera di elettroporazione (microcentrifuga coperchio di riempimentoED con 120 ml di soluzione contenente plasmide). </li><li> Usando pinzette Dumont curvi trasferire una tazza retinica alla camera di elettroporazione (scavando, non pressatura), e posizionarlo all&#39;interno dell&#39;elettrodo sagomato &#39;U&#39;, con la parte posteriore della retina verso il fondo dell&#39;elettrodo e la lente rivolta verso l&#39;alto ( Figura 2D). </li><li> Posizionare l&#39;anodo in modo che tocchi la parte anteriore dell&#39;occhio, accanto alla lente, e utilizzando pedale del electroporator fornire gli impulsi elettrici. </li><li> Trasferire tazza retina elettroporate in un piatto Petri con CMF-HBSS e ripetere la procedura di elettroporazione con ciascuno dei restanti tazze retiniche. NOTA: Fino a 6 tazze retina può essere elettroporate con la stessa soluzione plasmide senza una significativa diminuzione efficienza di trasfezione. </li><li> Rimuovere la lente e corpo vitreo di ogni coppa retinica elettroporate da loro presa con Bonn pinza dentata e tirando dolcemente attraverso tegli pupilla apertura tenendo l&#39;occhio in posizione con la parte posteriore delle pinzette Dumont curve. </li><li> Procedere alla dissociazione e la cultura delle cellule della retina elettroporate seguenti procedure standard. NOTA: per un protocollo dettagliato sulla dissociazione e la cultura di cellule retiniche pulcino si riferiscono a Vergara e Canto-Soler 2012, sui file 4 21 In questo protocollo le cellule vengono seminate a bassa densità su 6 pozzetti poliornitina rivestite o 35. piatti -mm (6 x 10 5 cellule / 35 mm di diametro e o piatto). Il mezzo utilizzato è medium 199 con penicillina / glutammina, siero di vitello fetale al 10% (FCS), e acido linoleico-BSA a 100 ug / ml. Le colture vengono mantenute in un umidificata 37 ° C incubatore con 5% di CO 2. Con questa procedura, 5 - 6 x 10 6 cellule in genere può essere ottenuto per ogni fase 27 occhio elettroporate. NOTA: Idealmente, non più di 3 ore dovrebbe passare tra il prelievo e la placcatura delle cellule, per assicurare una buona sopravvivenza cellularee ridurre al minimo lo stress. Una tipica temporizzazione per l&#39;osservazione e l&#39;ulteriore analisi è dopo 4 giorni di coltura, poiché a questo punto le cellule hanno raggiunto una buona differenziazione morfologica e molecolare e la sopravvivenza è ancora alto. </li></ol></li></ol>

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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=Evaluation+of+gene+promoters+for+liver+expression+by+hydrodynamic+gene+transfer.">Evaluation of gene promoters for liver expression by hydrodynamic gene transfer.</a> J Surg Res. 148 (1), 60-66 (2008).</li><li>Xu, L., 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=CMV-beta-actin+promoter+directs+higher+expression+from+an+adeno-associated+viral+vector+in+the+liver+than+the+cytomegalovirus+or+elongation+factor+1+alpha+promoter+and+results+in+therapeutic+levels+of+human+factor+X+in+mice.">CMV-beta-actin promoter directs higher expression from an adeno-associated viral vector in the liver than the cytomegalovirus or elongation factor 1 alpha promoter and results in therapeutic levels of human factor X in mice.</a> Hum Gene Ther. 12 (5), 563-573 (2001).</li><li>You, L. M., 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=A+hybrid+promoter-containing+vector+for+direct+cloning+and+enhanced+expression+of+PCR-amplified+ORFs+in+mammalian+cells.">A hybrid promoter-containing vector for direct cloning and enhanced expression of PCR-amplified ORFs in mammalian cells.</a> Mol Biol Rep. 37 (6), 2757-2765 (2009).</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.">A series of normal stages in the development of the chick embryo.</a> Dev Dyn. 195 (4), 231-272 (1992).</li></ol>

The authors declare that they have no competing financial interests or other conflicts of interest.

La fase più critica per il successo di questo protocollo è la selezione della fase appropriata degli embrioni. In pubblicazioni precedenti, una serie di stadi embrionali è dato per queste colture, tipicamente definito dai giorni di incubazione o embrionali giorni (ED); così è di solito presume che l&#39;utilizzo ED 5 a ED 6 embrioni produrrà risultati equivalenti. Tuttavia abbiamo trovato che sulla fase 27 (ED 5), l&#39;efficienza di trasfezione sarà circa il 22% della popolazione cellulare totale, come indicato ...

Colture di cellule dissociate da retine pulcino embrionali sono stati ampiamente utilizzati per studiare vari aspetti della biologia cellulare dei fotorecettori, tra cui la loro sopravvivenza 2-9, differenziazione 10-12, crescita dei neuriti 13, e altro ancora. I vantaggi di questo sistema, sviluppato nel 1980 da Ruben Adler e collaboratori e perfezionati dai suoi e altri gruppi 14-20, risiedono nelle caratteristiche intrinseche del pulcino come un modello animale 21. Le grandi dimensioni dell&#39;occhio pulcino, anche a stadi embrionali, fornisce una grande quantità di materiali per le culture. Inoltre, quando le culture vengono eseguite utilizzando giorno embrionale (ED) 5 - 6 retine, 55-80% dei loro cellule progenitrici differenziarsi come fotorecettori 14,15,18,22,23, e dal momento che circa il 86% dei fotorecettori in questo animale sono coni 24, queste culture sono particolarmente adatti per studi che mettono in questo tipo cellulare. Abbiamo recentemente sviped e caratterizzato una semplice tecnica che consente ad alta efficienza plasmide trasfezione delle cellule in queste culture, ampliando così l&#39;utilità di questo sistema facilitando studi missexpression genetica 1. Lo sviluppo di questa tecnica derivava da un vuoto nella letteratura scientifica di metodi che fornisca un livello accettabile di trasfezione per consentire lo studio della funzione genica in maniera autonoma cella. Ciò è in parte perché colture neuronali primarie sono notoriamente difficili da trasfettare 25,26. Alcune delle tecniche più utilizzate in precedenza disponibili per questo scopo inclusi metodi di transfezione chimici quali lipofezione o calcio trasfezione fosfato-mediata, che determinano efficienze dell&#39;ordine del 3-5% e possono esercitare una notevole tossicità 27-32. Anche se l&#39;uso di plasmidi con un sistema reporter enzimatico può aggirare il problema della scarsa efficienza di trasfezione amplificando il segnale, non lo fannodiscriminare effetti specifici delle cellule, ed i loro risultati sono basati su una piccola popolazione di cellule che potrebbe non essere rappresentativo dell&#39;intero. Un altro metodo ampiamente usato al pulcino, infezione da virus RCA, è applicabile solo alle cellule proliferanti e quindi non adatto a questo sistema di coltura retinico primario 33. Nel protocollo corrente occhi pulcino embrionale sono enucleati nella fase 27 (ED 5), l&#39;epitelio pigmentato retinico (RPE) viene rimosso, e la coppa retinica è posto in una camera di elettroporazione riempita con una soluzione plasmide contenente e elettroporate con misura elettrodi, seguita da dissociazione della retina e della cultura utilizzando tecniche standard 21. Dopo ottimizzare questa procedura siamo stati in grado di ottenere sempre efficienza di trasfezione dell&#39;ordine del 22% del numero totale di cellule in coltura e 25% nella popolazione fotorecettore sola, senza compromettere le caratteristiche di sopravvivenza e la differenziazione delleculture 1. Qui forniamo un protocollo dettagliata che illustra tutte le fasi importanti di questa procedura al fine di assicurare il successo e la riproducibilità di questa tecnica.

<table><tbody><tr><td>ECM 830 Electro Square Porator</td><td>BTX/ Harvard Apparatus</td><td>45-0052</td><td></td></tr><tr><td>Genetrode, L-Shaped, 5 mm Gold Tip</td><td>BTX/ Harvard Apparatus</td><td>45-0115 model 512</td><td>Gold tipped electrode used as anode</td></tr><tr><td>Polyimide Tubing</td><td>Vention Medical</td><td>custom made</td><td>Internal Diameter: 0.5 mm/wall thickness: 0.15 - 0.2 mm. Used for insulating gold tiped electrode</td></tr><tr><td>2.5 mm square box filament, 4.5 mm wide</td><td>Sutter Instrument Company</td><td>FB245B</td><td>Used to make cathode electrode</td></tr><tr><td>HBSS, no calcium, no magnesium, no phenol red</td><td>Gibco - Life Technologies</td><td>14175-095</td><td></td></tr><tr><td>Moloney forceps</td><td>Roboz</td><td>RS-8254</td><td>Serrated; Slight Curve; 4.5&quot; Length</td></tr><tr><td>Dumont tweezers 5/45</td><td>Roboz</td><td>RS-5058</td><td>Pattern #5, 45 Degree Angle; .10 X .06mm Tip Size; 109mm Length</td></tr><tr><td>Bonn micro forceps, 1x2 teeth</td><td>Roboz</td><td>RS-5172</td><td>Tying Platform; 1x2 Teeth, 0.12 mm Teeth; 3.75&quot; Length; 0.3 mm Tip Width</td></tr></tbody></table>

efficient gene transfer in chick retinas for primary cell culture studies: an ex-ovo electroporation approach

Le culture dei fotorecettori arricchito cono derivati ​​da retine pulcino embrionali sono diventati uno strumento indispensabile per i ricercatori di tutto il mondo che studiano la biologia dei neuroni della retina, in particolare fotorecettori. Le applicazioni di questo sistema vanno oltre la ricerca di base, in quanto possono essere facilmente adattate alle alte tecnologie throughput per lo sviluppo di farmaci. Tuttavia, la manipolazione genetica dei fotorecettori retinici in queste culture ha dimostrato di essere molto impegnativo, che costituiscono una limitazione importante per l&#39;utilità del sistema. Abbiamo recentemente sviluppato e validato un ex ovo tecnica plasmide elettroporazione che aumenta il tasso di trasfezione di cellule retiniche in queste culture per cinque volte rispetto ad altri protocolli attualmente disponibili 1. In questo metodo occhi pulcino embrionale sono enucleati nella fase 27, l&#39;RPE viene rimosso, e la coppa retinica viene posto in una soluzione contenente plasmide e elettroporate utilizzando CUSTOM- facilmente costruitoelettrodi in. Le retine sono poi dissociate e coltivate utilizzando le procedure standard. Questa tecnica può essere applicata a studi overespressione nonché alla downregulation dell&#39;espressione genica, per esempio attraverso l&#39;uso della tecnologia RNAi plasmide-driven, comunemente ottenendo l&#39;espressione del transgene nel 25% della popolazione fotorecettori. Il formato video di questa pubblicazione rendere questa tecnologia facilmente accessibile ai ricercatori del settore, che consente lo studio della funzione dei geni in colture primarie della retina. Abbiamo incluso anche spiegazioni dettagliate sulle fasi critiche di questa procedura per un esito positivo e la riproducibilità.

Qui vi presentiamo un semplice protocollo per plasmide trasfezione in enucleate pulcino tazze retina per la successiva coltura cellulare dissociata. Trasfezione si ottiene elettroporazione utilizzando facile fare elettrodi personalizzati (Figure 1 - 2). I parametri descritti in questo protocollo sono stati ottimizzati per ottenere efficienze di trasfezione che variano tra il 20 e il 27% (con una media del 22%) (Figura 3D). Si noti che, per le ragioni sopra esposte, questi risultati sono...

Watch this Scientific Journal Video about Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach at JoVE.com

Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach

Pulcino colture di cellule della retina embrionali costituiscono validi strumenti per lo studio della biologia dei fotorecettori. Abbiamo sviluppato una tecnica di trasferimento genico efficace sulla base di ex ovo plasmide elettroporazione delle retine precedenti alla cultura. Questa tecnica aumenta considerevolmente l&#39;efficienza di transfezione su protocolli attualmente disponibili, rendendo la manipolazione genetica fattibile per questo sistema.

Trasferimento efficiente Gene in Chick retine per cellulari primarie Cultura Studies: An<em&gt; Ex-ovo</em&gt; Elettroporazione Approach

The cone photoreceptor-enriched cultures derived from embryonic chick retinas have become an indispensable tool for researchers around the world studying ...

efficient-gene-transfer-chick-retinas-for-primary-cell-culture

Research

JoVE Journal

Developmental Biology

Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach

8.1K Views.  The Johns Hopkins University School of Medicine.  Pulcino colture di cellule della retina embrionali costituiscono validi strumenti per lo studio della biologia dei fotorecettori. Abbiamo sviluppato una tecnica di trasferimento genico efficace sulla base di ex ovo plasmide elettroporazione delle retine precedenti alla cultura. Questa tecnica aumenta considerevolmente l'efficienza di transfezione su protocolli attualmente disponibili, rendendo la manipolazione genetica fattibile per questo sistema. 

Video: Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach

Culture of Embryonic Mouse Cochlear Explants and Gene Transfer by Electroporation

Auditory hair cells located within the mouse organ of Corti detect and transmit sound information to the central nervous system. The mechanosensory hair cells are aligned in one row of inner hair cells and three rows of outer hair cells that extend along the basal to apical axis of the cochlea. The explant culture technique described here provides an efficient method to isolate and maintain cochlear explants from the embryonic mouse inner ear. Also, the morphology and molecular characteristics of sensory hair cells and nonsensory supporting cells within the cochlear explant cultures resemble those observed in vivo and can be studied within its intrinsic cellular environment. The cochlear explants can serve as important experimental tools for the identification and characterization of molecular and genetic pathways that are involved in cellular specification and patterning. Although transgenic mouse models provide an effective approach for gene expression studies, a considerable number of mouse mutants die during embryonic development thereby hindering the analysis and interpretation of developmental phenotypes. The organ of Corti from mutant mice that die before birth can be cultured so that their in vitro development and responses to different factors can be analyzed. Additionally, we describe a technique for electroporating embryonic cochlear explants ex vivo which can be used to downregulate or overexpress specific gene(s) and analyze their potential endogenous function and test whether specific gene product is necessary or sufficient in a given context to influence mammalian cochlear development1-8.

We present a method that describes isolation and culture of cochlear explants from embryonic mouse inner ear. We also demonstrate a method for gene transfer into cochlear explants via square-wave electroporation. The in vitro explant culture coupled with gene transfer technique enables researchers to study the effects of altering gene expression during development.

Cultura della embrionali di topo cocleari espianti e Gene Transfer con elettroporazione

Auditory hair cells located within the mouse organ of Corti detect and transmit sound information to the central nervous system. The mechanosensory hair ...

Ricerca

Biologia dello sviluppo

Whole Retinal Explants from Chicken Embryos for Electroporation and Chemical Reagent Treatments

The retina is a good model for the developing central nervous system. The large size of the eye and most importantly the accessibility for experimental manipulations in ovo/in vivo makes the chicken embryonic retina a versatile and very efficient experimental model. Although the chicken retina is easy to target in ovo by intraocular injections or electroporation, the effective and exact concentration of the reagents within the retina may be difficult to fully control. This may be due to variations of the exact injection site, leakage from the eye or uneven diffusion of the substances. Furthermore, the frequency of malformations and mortality after invasive manipulations such as electroporation is rather high.
This protocol describes an ex ovo technique for culturing whole retinal explants from chicken embryos and provides a method for controlled exposure of the retina to reagents. The protocol describes how to dissect, experimentally manipulate, and culture whole retinal explants from chicken embryos. The explants can be cultured for approximately 24 hr and be subjected to different manipulations such as electroporation. The major advantages are that the experiment is not dependent on the survival of the embryo and that the concentration of the introduced reagent can be varied and controlled in order to determine and optimize the effective concentration. Furthermore, the technique is rapid, cheap and together with its high experimental success rate, it ensures reproducible results. It should be emphasized that it serves as an excellent complement to experiments performed in ovo.

This protocol describes a method to dissect, experimentally manipulate and culture whole retinal explants from chicken embryos. The explant cultures are useful when high success rate, efficacy and reproducibility are needed to test the effects of plasmids for electroporation and/or reagent substances, i.e., enzymatic inhibitors.

Espianti di retina intero da pollo embrioni per trattamenti di elettroporazione e Agenti chimici

The retina is a good model for the developing central nervous system. The large size of the eye and most importantly the accessibility for experimental ...

In vivo Electroporation of Developing Mouse Retina

The functional characterization of genes expressed during mammalian retinal development remains a significant challenge. Gene targeting to generate constitutive or conditional loss of function knockouts remains cost and labor intensive, as well as time consuming. Adding to these challenges, retina expressed genes may have essential roles outside the retina leading to unintended confounds when using a knockout approach. Furthermore, the ability to ectopically express a gene in a gain of function experiment can be extremely valuable when attempting to identify a role in cell fate specification and/or terminal differentiation.
We present a method for the rapid and efficient incorporation of DNA plasmids into the neonatal mouse retina by electroporation. The application of short electrical impulses above a certain field strength results in a transient increase in plasma membrane permeability, facilitating the transfer of material across the membrane 1,2,3,4. Groundbreaking work demonstrated that electroporation could be utilized as a method of gene transfer into mammalian cells by inducing the formation of hydrophilic plasma membrane pores allowing the passage of highly charged DNA through the lipid bilayer 5. Continuous technical development has resulted in the viability of electroporation as a method for in vivo gene transfer in multiple mouse tissues including the retina, the method for which is described herein 6, 7, 8, 9, 10. 
DNA solution is injected into the subretinal space so that DNA is placed between the retinal pigmented epithelium and retina of the neonatal (P0) mouse and electrical pulses are applied using a tweezer electrode. The lateral placement of the eyes in the mouse allows for the easy orientation of the tweezer electrode to the necessary negative pole-DNA-retina-positive pole alignment. Extensive incorporation and expression of transferred genes can be identified by postnatal day 2 (P2). Due to the lack of significant lateral migration of cells in the retina, electroporated and non-electroporated regions are generated. Non-electroporated regions may serve as internal histological controls where appropriate. 
Retinal electroporation can be used to express a gene under a ubiquitous promoter, such as CAG, or to disrupt gene function using shRNA constructs or Cre-recombinase. More targeted expression can be achieved by designing constructs with cell specific gene promoters. Visualization of electroporated cells is achieved using bicistronic constructs expressing GFP or by co-electroporating a GFP expression construct. Furthermore, multiple constructs may be electroporated for the study of combinatorial gene effects or simultaneous gain and loss of function of different genes. Retinal electroporation may also be utilized for the analysis of genomic cis-regulatory elements by generating appropriate expression constructs and deletion mutants. Such experiments can be used to identify cis-regulatory regions sufficient or required for cell specific gene expression 11. Potential experiments are limited only by construct availability.

In vivo Electroporation of Developing Mouse Retina

A method for the incorporation of plasmid DNA into murine retinal cells for the purpose of performing either gain- or loss of function studies in vivo is presented. This method capitalizes on the transient increase in permeability of cell plasma membranes induced by the application of an external electrical field.

In elettroporazione in vivo di Retina topo in via di sviluppo

The functional characterization of genes expressed during mammalian retinal development remains a significant challenge.  Gene targeting to generate ...

Neuroscienze

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 ...

In utero and ex vivo Electroporation for Gene Expression in Mouse Retinal Ganglion Cells

The retina and its sole output neuron, the retinal ganglion cell (RGC), comprise an excellent model in which to examine biological questions such as cell differentiation, axon guidance, retinotopic organization and synapse formation[1]. One drawback is the inability to efficiently and reliably manipulate gene expression in RGCs in vivo, especially in the otherwise accessible murine visual pathways. Transgenic mice can be used to manipulate gene expression, but this approach is often expensive, time consuming, and can produce unwanted side effects. In chick, in ovo electroporation is used to manipulate gene expression in RGCs for examining retina and RGC development. Although similar electroporation techniques have been developed in neonatal mouse pups[2], adult rats[3], and embryonic murine retinae in vitro[4], none of these strategies allow full characterization of RGC development and axon projections in vivo. To this end, we have developed two applications of electroporation, one in utero and the other ex vivo, to specifically target embryonic murine RGCs[5, 6]. 
With in utero retinal electroporation, we can misexpress or downregulate specific genes in RGCs and follow their axon projections through the visual pathways in vivo, allowing examination of guidance decisions at intermediate targets, such as the optic chiasm, or at target regions, such as the lateral geniculate nucleus. Perturbing gene expression in a subset of RGCs in an otherwise wild-type background facilitates an understanding of gene function throughout the retinal pathway. Additionally, we have developed a companion technique for analyzing RGC axon growth in vitro. We electroporate embryonic heads ex vivo, collect and incubate the whole retina, then prepare explants from these retinae several days later. Retinal explants can be used in a variety of in vitro assays in order to examine the response of electroporated RGC axons to guidance cues or other factors. In sum, this set of techniques enhances our ability to misexpress or downregulate genes in RGCs and should greatly aid studies examining RGC development and axon projections.

In utero and ex vivo Electroporation for Gene Expression in Mouse Retinal Ganglion Cells

Here we present two techniques for manipulating gene expression in murine retinal ganglion cells (RGCs) by in utero and ex vivo electroporation. These techniques enable one to examine how alterations in gene expression affect RGC development, axon guidance, and functional properties.

In elettroporazione in vivo ed ex utero per l&#39;espressione genica in cellule gangliari della retina del mouse

The retina and its sole output neuron, the retinal ganglion cell (RGC), comprise an excellent model in which to examine biological questions such as cell ...

Biologia

Visualization of Tangential Cell Migration in the Developing Chick Optic Tectum

Time-lapse imaging is a powerful method to analyze migrating cell behavior. After fluorescent cell labeling, the movement of the labeled cells in culture can be recorded under video microscopy. For analyzing cell migration in the developing brain, slice culture is commonly used to observe cell migration parallel to the slice section, such as radial cell migration. However, limited information can be obtained from the slice culture method to analyze cell migration perpendicular to the slice section, such as tangential cell migration. Here, we present the protocols for time-lapse imaging to visualize tangential cell migration in the developing chick optic tectum. A combination of cell labeling by electroporation in ovo and a subsequent flat-mount culture on the cell culture insert enables detection of migrating cell movement in the horizontal plane. Moreover, our method facilitates detection of both individual cell behavior and the collective action of a group of cells in the long term. This method can potentially be applied to detect the sequential change of the fluorescent-labeled micro-structure, including the axonal elongation in the neural tissue or cell displacement in the non-neural tissue.

We describe the methods for fluorescent labeling of tangentially migrating cells by electroporation, and for time-lapse imaging of the labeled cell movement in a flat-mount culture in order to visualize migrating cell behavior in the developing chick optic tectum.

Visualizzazione della migrazione cellulare tangenziale nel Tectum ottica di pulcino in via di sviluppo

Time-lapse imaging is a powerful method to analyze migrating cell behavior. After fluorescent cell labeling, the movement of the labeled cells in culture ...

In Ovo and Ex Ovo Methods to Study Avian Inner Ear Development

The inner ear perceives sound and maintains balance using the cochlea and vestibule. It does this by using a dedicated mechanosensory cell type known as the hair cell. Basic research in the inner ear has led to a deep understanding of how the hair cell functions, and how dysregulation can lead to hearing loss and vertigo. For this research, the mouse has been the pre-eminent model system. However, mice, like all mammals, have lost the ability to replace hair cells. Thus, when trying to understand cellular therapies for restoring inner ear function, complementary studies in other vertebrate species could provide further insights. The auditory epithelium of birds, the basilar papilla (BP), is a sheet of epithelium composed of mechanosensory hair cells (HCs) intercalated by supporting cells (SCs). Although the anatomical architecture of the basilar papilla and the mammalian cochlea differ, the molecular mechanisms of inner ear development and hearing are similar. This makes the basilar papilla a useful system for not only comparative studies but also to understand regeneration. Here, we describe dissection and manipulation techniques for the chicken inner ear. The technique shows genetic and small molecule inhibition methods, which offer a potent tool for studying the molecular mechanisms of inner ear development. In this paper, we discuss in ovo electroporation techniques to genetically perturb the basilar papilla using CRIPSR-Cas9 deletions, followed by dissection of the basilar papilla. We also demonstrate the BP organ culture and optimal use of culture matrices, to observe the development of the epithelium and the hair cells.

In Ovo and Ex Ovo Methods to Study Avian Inner Ear Development

The chick is a cost-effective, accessible, and widely available model organism for a variety of studies. Here, a series of protocols is detailed to understand the molecular mechanisms underlying avian inner ear development and regeneration.

Metodi Ovo ed Ex Ovo per studiare lo sviluppo dell'orecchio interno aviario

The inner ear perceives sound and maintains balance using the cochlea and vestibule. It does this by using a dedicated mechanosensory cell type known as ...

In Ovo Electroporation in Embryonic Chick Retina

Chicken embryonic retina is an excellent tool to study retinal development in higher vertebrates. Because of large size and external development, it is comparatively very easy to manipulate the chick embryonic retina using recombinant DNA/RNA technology. Electroporation of DNA/RNA constructs into the embryonic retina have a great advantage to study gene regulation in retinal stem/progenitor cells during retinal development. Different type of assays such as reporter gene assay, gene over-expression, gene knock down (shRNA) etc. can be performed using the electroporation technique. This video demonstrates targeted retinal injection and in ovo electroporation into the embryonic chick retina at the Hamburger and Hamilton stage 22-23, which is about embryonic day 4 (E4). Here we show a rapid and convenient in ovo electroporation technique whereby a plasmid DNA that expresses green fluorescent protein (GFP) as a marker is directly delivered into the chick embryonic subretinal space and followed by electric pulses to facilitate DNA uptake by retinal stem/progenitor cells. The new method of retinal injection and electroporation at E4 allows the visualization of all retinal cell types, including the late-born neurons1, which has been difficult with the conventional method of injection and electroporation at E1.52.

In Ovo Electroporation in Embryonic Chick Retina

The overall goal of this video is to show how to perform targeted retinal injection and in ovo electroporation of DNA/RNA constructs into the chick embryonic retina at the Hamburger and Hamilton stage 22-23, which is about embryonic day 4 (E4). This technique is very useful to study gene expression, gene regulation, and morphological change in developing chick retina.

In elettroporazione Ovo in Retina Chick Embryonic

Chicken embryonic retina is an excellent tool to study retinal development in higher vertebrates. Because of large size and external development, it is ...

Gene Transfer into Older Chicken Embryos by ex ovo Electroporation

The chicken embryo provides an excellent model system for studying gene function and regulation during embryonic development. In ovo electroporation is a powerful method to over-express exogenous genes or down-regulate endogenous genes in vivo in chicken embryos1. Different structures such as DNA plasmids encoding genes2-4, small interfering RNA (siRNA) plasmids5, small synthetic RNA oligos6, and morpholino antisense oligonucleotides7 can be easily transfected into chicken embryos by electroporation. However, the application of in ovo electroporation is limited to embryos at early incubation stages (younger than stage HH20 - according to Hamburg and Hamilton)8 and there are some disadvantages for its application in embryos at later stages (older than stage HH22 - approximately 3.5 days of development). For example, the vitelline membrane at later stages is usually stuck to the shall membrane and opening a window in the shell causes rupture of the vessels, resulting in death of the embryos; older embryos are covered by vitelline and allantoic vessels, where it is difficult to access and manipulate the embryos; older embryos move vigorously and is difficult to control the orientation through a relatively small window in the shell.
In this protocol we demonstrate an ex ovo electroporation method for gene transfer into chicken embryos at late stages (older than stage HH22). For ex ovo electroporation, embryos are cultured in Petri dishes9 and the vitelline and allantoic vessels are widely spread. Under these conditions, the older chicken embryos are easily accessed and manipulated. Therefore, this method overcomes the disadvantages of in ovo electroporation applied to the older chicken embryos. Using this method, plasmids can be easily transfected into different parts of the older chicken embryos10-12.

Gene Transfer into Older Chicken Embryos by ex ovo Electroporation

A method of gene transfer into chicken embryos at later incubation stages (older than Hamburger and Hamilton stage (HH) 22) is described. This method overcomes disadvantages of in ovo electroporation applied to older chicken embryos and is a useful technique to study gene function and regulation at older developmental stages.

Il trasferimento genico in embrioni di pollo da anziani<em&gt; Ex ovo</em&gt; Elettroporazione

The chicken embryo provides an  excellent model system for studying gene function and regulation during  embryonic development. In ovo electroporation is ...

Loss-of-Function Approach in the Embryonic Chick Retina by Using Tol2 Transposon-Mediated Transgenic Expression of Artificial microRNAs

The chick retina has long been an important model system in developmental neurobiology, with advantages including its large size, rapid development, and accessibility for visualization and experimental manipulations. However, its major technical limitation had been the lack of robust loss-of-function approaches for gene function analyses. This protocol describes a methodology of gene silencing in the developing chick retina that involves transgenic expression of artificial microRNAs (miRNAs) by using the Tol2 transposon system. In this approach, a Tol2 transposon plasmid that contains an expression cassette for the EmGFP (emerald green fluorescent protein) marker and artificial pre-miRNA sequences against a target gene is introduced into the embryonic chick retina with a Tol2 transposase expression construct by in ovo electroporation. In the transfected retinal cells, the transposase catalyzes the excision of the expression cassette from the transposon vector and its integration into host chromosomes, leading to the stable expression of miRNAs and the EmGFP protein. In our previous study, we have demonstrated that the expression of Nel, a glycoprotein that exerts multiple functions in neural development, can be significantly suppressed in the developing chick retina by using this technique. Our results indicate that this methodology induces a stable and robust suppression of gene expression and thus provides an efficient loss-of-function approach for studies of retinal development.

We have developed a novel loss-of-function approach that involves the introduction and genomic integration of artificial micro-RNA sequences into chick embryos by using in ovo electroporation and the Tol2 transposon system. This technique provides a robust and stable gene knockdown methodology for studies of gene function during development.

Approccio alla perdita di funzione nella retina embrionale del pulcino utilizzando l'espressione transgenica mediata dal trasposone Tol2 di microRNA artificiali

The chick retina has long been an important model system in developmental neurobiology, with advantages including its large size, rapid development, and ...

Trasferimento efficiente Gene in Chick retine per cellulari primarie Cultura Studies: An

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