Questo progetto di ricerca è stata sostenuta da un supplemento ARRA, 5 R01 NS056380. Ulteriore supporto è stato fornito tramite il vettore virale Core e Core Microscopia della Emory Neuroscienze NINDS Nucleo Facilities Grant, P30NS055077. Ringraziamo il mouse Emory transgenico e Gene Targeting Nucleo per derivare la linea di mouse da GENSAT; Greg Pazour per il SSTR3-GFP linea cellulare IMCD3 stabile e Bradley Yoder per il SSTR3-GFP lentivirali costruiamo. Gli anticorpi monoclonali sono stati ottenuti da studi di sviluppo Hybridoma Banca, sviluppato sotto l&#39;egida del NICHD, e mantenuto dalla University of Iowa, Dipartimento di Scienze Biologiche, Iowa City, IA 52242. Tutte le procedure di animali sono stati approvati dal IACUC e del Comitato Biosicurezza alla Emory University.

Topi adulti sono sacrificati per dislocazione cervicale meccanico. Tutte le procedure di animali sono stati approvati dal IACUC e del Comitato Biosicurezza alla Emory University. 1. Generazione Embryo <ol><li> Croce tamoxifene-inducibile Cre linea, CAGGCreER, e la linea giornalista dsRedCre (Tg (CAG-Bgeo,-DsRed * MST) 1Nagy) (Figura 1) 5,6. Per monitorare la relativa tempistica di risposta Shh nelle cellule figlie, croce CAGGCreER e DsRed linea con il Olig2-eGFP BAC topi transgenici (Tg (Olig2-EGFP) EK23Gsat) (Figura 1) 7,8. </li><li> Sciogliere tamoxifene in 100% di etanolo, ed eseguire l&#39;iniezione intraperitoneale di 2,5 mg di tamoxifene per 40 g di peso corporeo nelle femmine gravide a 6,5 ​​embrionale (E6.5) per indurre l&#39;espressione Cre ed etichettatura DsRed in un piccolo sottogruppo di cellule. </li><li> 48 ore più tardi sezionare embrioni, identificare gli embrioni positivi DsRed utilizzando il microscopio a fluorescenza, trasferirli al piatto cultura e osservatoriposta divisioni cellulari singoli durante ex vivo imaging (vedi sotto). </li></ol> 2. Tutta mouse Embrione Cultura <ol><li> Sezionare embrioni E8.5 nel medio lavaggio preriscaldata contenente DMEM/F12 (1:1) supplementato con 10% di siero di vitello neonato e 1% di penicillina / streptomicina (P / S) 9. </li><li> Direttamente dopo la dissezione, posto embrioni sulla ° C fase di riscaldamento 37 al microscopio a fluorescenza e di identificare come GFP e / o DsRed positivo (vedi sotto). </li><li> Trasferire fino a 2 embrioni in 500 microlitri goccia di terreni di coltura pre-equilibrata contenente 50% siero di ratto da un maschio Sprague-Dawley e il 50% DMEM/F12 (1:1) senza rosso fenolo integrato con L-glutammina e 1% di 1 M HEPES in NaCl 0,85% e P / S 9. </li><li> Applicare uno strato sottile (0.1 cm) di olio minerale leggero equilibrata nel medio per evitare l&#39;evaporazione e trasferire il piatto di coltura contenente gli embrioni ai 37 ° C, 5% CO 2 incubatore. </li></ol> 3.Infezione virale <ol><li> Al fine di etichetta cilia nel neuroepitelio, aggiungere 5-10 ml di SSTR3-GFP lentivirus, circa 2 milioni di virioni, ad un 500 microlitri goccia equilibrata di terreno di coltura contenente un embrione E8.5. </li><li> Dopo 18 ore di coltura, il trasferimento di embrioni infetti in diverse gocce di mezzo di lavaggio per lavare il virus e preparare fetta del tubo neurale. </li></ol> 4. Del tubo neurale Slice Preparazione per Live Imaging <ol><li> Sezionare tubo neurale del E8.5 embrione in media lavaggio pre-riscaldato utilizzando un formato micro-coltello 0,025 millimetri, su un piatto rivestito di agar 1%. </li><li> Posizionare il tubo laterale isolato neurale ventrale giù in una goccia 150 ml di terreno di coltura equilibrato senza rosso fenolo sulla mm rivestito di vetro piatto fondo di poli-L-lisina 35. </li><li> Mettere una piccola quantità di una miscela 1:1 realizzato da gelatina pura al 100% di petrolio e cera fusa (candela da IKEA) attorno al tubo neurale montato, e premere delicatamente da una stretta lingua di coprioggetto di vetro, al fine diimmobilizzare il campione. </li><li> Coprire il piatto con un sottile strato (~ 0,1 centimetri) di olio minerale leggero equilibrata (Figura 2). </li></ol> 5. Vivere Imaging e Time-lapse Microscopia confocale <ol><li> Luogo piatto sotto la Nikon A1R confocale microscopio invertito dotato di una camera climatica che regola la temperatura, impostata a 37 ° C, e il 5% di CO 2. </li><li> Utilizzare 60x obiettivo ad immersione in olio a registrare GFP ciglia etichettati e cellule positive DsRed, mentre l&#39;uso obiettivo ad immersione in olio 40x per monitorare Olig2-GFP e cellule positive DsRed. </li><li> Aprire il software NIS Elements per creare le condizioni di imaging lasso di tempo. Ogni 10 min acquisire z-stack fino a 25 micron con una spaziatura di 1,5 micron (obiettivo 40x) e fino a 8 micron con una spaziatura di 0,4 micron (60x obiettivo). Usare 488 e 561 nm, la lunghezza d&#39;onda di eccitazione e di canali trasmessi, se necessario. Acquisire immagini in formato 512 x 512. Impostare più regioni definite dall&#39;utente di interest per eseguire la registrazione simultanea. Ottima esposizione al potere del laser e la luminosità dell&#39;immagine è stata regolata mediante l&#39;uso del laser a bassa intensità (fino al 11% per mCherry 561 e fino al 4,5% EGFP 405/488), velocità di scansione 1, media linea 2 e la dimensione del foro del perno (61 micron per DsRed; 28,1 micron per Olig2; 72 micron per SSTR3GFP; 61,3 micron per DsRed e SSTR3GFP; 58 micron per DsRed e Olig2). L&#39;uso di giornalisti fluorescenti geneticamente codificati ci ha permesso di rilevare la luminosità con basso potere del laser. </li><li> Analizzare i dati registrati utilizzando Imaris software di ricostruzione 3D. </li></ol> 6. Immunofluorescenza <ol><li> Fissare gli embrioni o tubi neurali isolate in paraformaldeide al 4% / 0,1 M tampone fosfato sul ghiaccio (4 ° C) per 1 ora in un piatto di vetro. </li><li> Lavare i campioni 2 ore in PBS su ghiaccio (4 ° C) (cambiamento PBS un paio di volte) e mettere nel 30% di saccarosio / 0,1 M tampone fosfato durante la notte o fino a quando gli embrioni lavandino. </li><li> Incorpora in ottobre, congelare in ghiaccio secco e conservare in -80 ° C. Peffettuare la giusta sezionamento sul criostato (10 mm). </li><li> Lavare i vetrini per 10 min in soluzione di lavaggio contenente siero ovino inattivato al calore 1% e 0,1% Triton X-100 in PBS. </li><li> Diluire gli anticorpi primari in soluzione di lavaggio a seguito di concentrazioni: Rat monoclonale anti-RFP (5F8,) 1:200; coniglio anti-ARL13B siero 1:1500 e topo monoclonale anti-ARL13B 01:05 (295B/54); coniglio anti-Olig2 1:300; monoclonali mouse Pax6, Shh e Nkx2.2-all 1:10; ed policlonale di coniglio Ki67 1:500. Aggiungere circa 150 ml per diapositiva nel piatto camera umidificata, coprire con parafilm per evitare la disidratazione e lasciare tutta la notte a 4 ° C. </li><li> Lavare i vetrini nella soluzione di lavaggio per tre volte, ogni volta 20 min a temperatura ambiente. </li><li> Diluire gli anticorpi secondari Alexa Fluor 488, 568, 350 nelle soluzioni di lavaggio a 1:200 concentrazione. Utilizzare Hoechst 1:3000 o TO-PRO-3 1:500 a macchia nuclei. Aggiungere 150 microlitri per vetrino, lasciare 1 ora a temperatura ambiente in camera umidificata al riparo dalla luce. </li><li> Lavare i vetrini nella soluzione di lavaggio two volte, ogni volta 30 min a temperatura ambiente. </li><li> Monte scivola nel 80% Prolungare Oro reagente anti-sbiadimento e la vista entro 24 ore. </li></ol>

<ol>
	<li>Yamada, T., Pfaff, S. L., Edlund, T., Jessell, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+cell+pattern+in+the+neural+tube:+motor+neuron+induction+by+diffusible+factors+from+notochord+and+floor+plate.">Control of cell pattern in the neural tube: motor neuron induction by diffusible factors from notochord and floor plate.</a> Cell. 73, 673-686 (1993).</li><li>Ericson, J., Muhr, J., Placzek, M., Lints, T., Jessell, T. M., Edlund, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sonic+hedgehog+induces+the+differentiation+of+ventral+forebrain+neurons:+A+common+signal+for+ventral+patterning+within+the+neural+tube.">Sonic hedgehog induces the differentiation of ventral forebrain neurons: A common signal for ventral patterning within the neural tube.</a> Cell. 81, 747-756 (1995).</li><li>Briscoe, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Homeodomain+Protein+Code+Specifies+Progenitor+Cell+Identity+and+Neuronal+Fate+in+the+Ventral+Neural+Tube.">Homeodomain Protein Code Specifies Progenitor Cell Identity and Neuronal Fate in the Ventral Neural Tube.</a> Cell. 101, 435-445 (2000).</li><li>Berbari, N. F., Johnson, A. D., Lewis, J. S., Askwith, C. C., Mykytyn, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+ciliary+localization+sequences+within+the+third+intracellular+loop+of+G+protein-coupled+receptors.">Identification of ciliary localization sequences within the third intracellular loop of G protein-coupled receptors.</a> Mol. Biol. Cell. 19 (4), 1540-1547 (2008).</li><li>Vintersten, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+in+red:+red+fluorescent+protein+expression+in+mouse+ES+cells,+embryos,+and+adult+animals.">Mouse in red: red fluorescent protein expression in mouse ES cells, embryos, and adult animals.</a> Genesis. 40 (4), 241-246 (2004).</li><li>Hayashi, S., McMahon, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+recombination+in+diverse+tissue+by+a+tamoxifen-inducible+form+of+Cre:+a+tool+for+temporally+regulated+gene+activation/inactivation+in+the+mouse.">Efficient recombination in diverse tissue by a tamoxifen-inducible form of Cre: a tool for temporally regulated gene activation/inactivation in the mouse.</a> Dev. Biol. 244 (2), 305-318 (2002).</li><li>Gong, S., Zheng, C., Doughty, M. L., Losos, K., Didkovsky, N., Schambra, U. B., Nowak, N. J., Joyner, A., Leblanc, G., Hatten, M. E., Heintz, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+gene+expression+atlas+of+the+central+nervous+system+based+on+bacterial+artificial+chromosomes.">A gene expression atlas of the central nervous system based on bacterial artificial chromosomes.</a> Nature. 425 (6961), 917-925 (2003).</li><li>Mukouyama, Y. S., Deneen, B., Lukaszewicz, A., Novitch, B. G., Wichterle, H., Jessell, T. M., Anderson, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Olig2++neuroepithelial+motoneuron+progenitors+are+not+multipotent+stem+cells+in+vivo.">Olig2+ neuroepithelial motoneuron progenitors are not multipotent stem cells in vivo.</a> Proc. Natl. Acad. Sci. U.S.A. 103 (5), 1551-1556 (2006).</li><li>Jones, E. A. V., Crotty, D., Kulesa, P. M., Waters, C. W., Baron, M. H., Fraser, S. E., Dickinson, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+in+vivo+imaging+of+postimplantation+mammalian+embryos+using+whole+embryo+culture.">Dynamic in vivo imaging of postimplantation mammalian embryos using whole embryo culture.</a> Genesis. 34, 228-235 (2002).</li><li>Piotrowska-Nitsche, K., Caspary, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Live+imaging+of+individual+cell+divisions+in+mouse+neuroepithelium+shows+asymmetry+in+cilium+formation+and+Sonic+hedgehog+response.">Live imaging of individual cell divisions in mouse neuroepithelium shows asymmetry in cilium formation and Sonic hedgehog response.</a> Cilia. 1 (6), (2012).</li><li>Nowotschin, S., Ferrer-Vaquer, A., Hadjantonakis, A. -. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+mouse+development+with+confocal+time-lapse+microscopy.">Imaging mouse development with confocal time-lapse microscopy.</a> Methods in Enzymology. 476, 351-377 (2010).</li></ol>

Nessun conflitto di interessi dichiarati.

Il nostro sistema ex vivo permette di osservare direttamente divisioni cellulari singoli all&#39;interno del neuroepitelio in tempo reale via di sviluppo. Come esempio abbiamo esaminato divisioni cellulari entro il mouse embrionale tubo neurale e vigilato o formazione ciglio o risposta Shh. Abbiamo confermato i nostri risultati di imaging (n = 24) erano coerenti con i risultati di sezioni fisse (n = 178) che indicano la nostra tecnica fornisce dati fisiologicamente rilevanti. <p class="jov...

<table border="1">
	<tbody>
		<tr>
			<td>Name of the reagent</td>
			<td>Company</td>
			<td>Catalogue number</td>
			<td>Comments (optional)</td>
		</tr>
		<tr>
			<td>Z/RED line (STOCK Tg(CAG-Bgeo,-DsRed*MST)1Nagy/J</td>
			<td>Jackson Laboratory</td>
			<td>005438</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Olig2-eGFP line (STOCK Tg(Olig2-EGFP)EK23Gsat/Mmcd</td>
			<td>MMRRC,</td>
			<td>010555-UCD</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>CAGGCreER</td>
			<td>Jackson Laboratory</td>
			<td>003724</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Tamoxifen</td>
			<td>Sigma</td>
			<td>T5648</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>DMEM/F12 (1:1)</td>
			<td>GIBCO</td>
			<td>21041-025</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Newborn calf serum</td>
			<td>Lonza</td>
			<td>14-416F</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin</td>
			<td>Invitrogen</td>
			<td>15140-122</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Rat Serum SD male</td>
			<td>Harlan Bioproducts</td>
			<td>4520</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>1M Hepes</td>
			<td>BioWhittaker</td>
			<td>17-737E</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>L-Glutamine</td>
			<td>GIBCO</td>
			<td>21041-025</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Light mineral oil</td>
			<td>Sigma</td>
			<td>M8410</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Sstr3-GFP lentivirus</td>
			<td>Emory Viral Core</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Micro-knife, size 0.025 mm</td>
			<td>Electron Microscopy Sciences</td>
			<td>62091</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>35 mm poly-L-lysine coated glass bottom dish</td>
			<td>MatTek</td>
			<td>P35GC-0-10-C</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>100% petroleum jelly</td>
			<td>Kroger</td>
			<td>FL9958c</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>A1R Laser Scanning Confocal Inverted Microscope</td>
			<td>Nikon</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>NIS Elements software</td>
			<td>Nikon</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Imaris 3D software</td>
			<td>Bitplane AG</td>
			<td>Imaris 7.2.3</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>OCT</td>
			<td>Tissue-Tek</td>
			<td>4583</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Cryostat</td>
			<td>Leica</td>
			<td>CM1850</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Heat-inactivated sheep serum</td>
			<td>Invitrogen</td>
			<td>16210-072</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Fisher Scientific</td>
			<td>BP151</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Parafolmaldehyde</td>
			<td>Sigma</td>
			<td>P6148</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Phosphate Buffer</td>
			<td>Lab made</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Rat monoclonal anti-RFP (5F8)</td>
			<td>Chromotek</td>
			<td>110411</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Rabbit anti-Arl13b serum</td>
			<td>NeuroMab</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>mouse monoclonal anti-Arl13b 1:5</td>
			<td>NeuroMab</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Rabbit anti-Olig2</td>
			<td>Chemicon</td>
			<td>AB9610</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Mouse monoclonals Pax6</td>
			<td>Developmental Hybridoma Bank</td>
			<td>Pax6</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Mouse monoclonalsShh</td>
			<td>Developmental Hybridoma Bank</td>
			<td>5E1</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Mouse monoclonals Nkx2.2</td>
			<td>Developmental Hybridoma Bank</td>
			<td>74.5A5</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Rabbit polyclonal Ki67</td>
			<td>Abcam</td>
			<td>AB15580</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Alexa Fluor 488</td>
			<td>Molecular Probes</td>
			<td>A11029</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Alexa Fluor 568</td>
			<td>Molecular Probes</td>
			<td>A11031</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Alexa Fluor 350</td>
			<td>Molecular Probes</td>
			<td>A11046</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Hoechst</td>
			<td>Fisher</td>
			<td>AC22989</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>TO-PRO-3</td>
			<td>Invitrogen</td>
			<td>T3605</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>ProLong Gold anti-fade reagent</td>
			<td>Invitrogen</td>
			<td>P36934</td>
			<td>&nbsp;</td>
		</tr>
	</tbody>
</table>

ex vivo live imaging of single cell divisions in mouse neuroepithelium

Abbiamo sviluppato un sistema che integra l&#39;imaging dal vivo di marcatori fluorescenti e fette di coltura embrionale neuroepithelium mouse. Abbiamo approfittato di linee del mouse esistenti per la cellula genetica lineage tracing: una linea di Cre tamoxifene-inducibile e una linea giornalista Cre esprimendo DsRed su ricombinazione Cre-mediata. Utilizzando un livello relativamente basso di tamoxifene, siamo stati in grado di indurre ricombinazione in un piccolo numero di cellule, permettendo di seguire divisioni cellulari individuali. Inoltre, abbiamo osservato la risposta trascrizionale di Sonic hedgehog (Shh) di segnalazione utilizzando un Olig2-eGFP transgenico linea 1-3 e abbiamo monitorato formazione di ciglia infettando la fetta colta con virus che esprime il marcatore di ciglia, SSTR3-GFP 4. Per l&#39;immagine del neuroepitelio, abbiamo raccolto gli embrioni a E8.5, isolato il tubo neurale, montata la fetta neurale in appropriate condizioni di coltura nella camera di imaging e di eseguita time-lapse imaging confocale. Il nostro exmetodo di imaging in vivo in diretta consente di tracciare divisioni cellulari singoli di valutare la relativa tempistica di formazione ciglia primarie e risposta Shh in modo fisiologicamente rilevanti. Questo metodo può essere facilmente adattato utilizzando marcatori fluorescenti distinti e fornisce il campo gli strumenti con cui monitorare il comportamento delle cellule in situ ed in tempo reale.

Qui abbiamo effettuato ex vivo imaging dal vivo di divisioni cellulari singoli all&#39;interno del E8.5 del mouse neuroepitelio. Per etichettare singole celle, abbiamo indotto ricombinasi Cre in un sottogruppo di cellule contenenti una linea giornalista Cre che esprimevano DsRed upon ricombinazione 5,6 (Figura 3A). Così, 48 ore dopo siamo stati in grado di osservare le divisioni cellulari singoli durante ex vivo imaging (Figure 4A-D). Allo stesso tempo, abb...

Watch this Scientific Journal Video about Ex vivo Live Imaging of Single Cell Divisions in Mouse Neuroepithelium at JoVE.com

Ex vivo Live Imaging of Single Cell Divisions in Mouse Neuroepithelium

Qui sviluppiamo gli strumenti necessari per<em&gt; Ex vivo</em&gt; L&#39;imaging dal vivo di tracciare divisioni cellulari singoli nel topo E8.5 neuroepitelio

Ex vivo Imaging in diretta di divisioni cellulari singoli in mouse neuroepitelio

We developed a system that integrates live imaging of fluorescent markers and culturing slices of embryonic mouse neuroepithelium. We took advantage of ...

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Neuroscience

Ex vivo Live Imaging of Single Cell Divisions in Mouse Neuroepithelium

10.3K Views.  Emory University School of Medicine. Qui sviluppiamo gli strumenti necessari per Ex vivo L'imaging dal vivo di tracciare divisioni cellulari singoli nel topo E8.5 neuroepitelio

Video: Ex vivo Live Imaging of Single Cell Divisions in Mouse Neuroepithelium

Multiple-mouse Neuroanatomical Magnetic Resonance Imaging

The field of mouse phenotyping with magnetic resonance imaging (MRI) is rapidly growing, motivated by the need for improved tools for characterizing and evaluating mouse models of human disease. MRI is an excellent modality for investigating genetically altered animals. It is capable of whole brain coverage, can be used in vivo, and provides multiple contrast mechanisms for investigating different aspects of neuranatomy and physiology. The advent of high-field scanners along with the ability to scan multiple mice simultaneously allows for rapid phenotyping of novel mutations.
Effective mouse MRI studies require attention to many aspects of experiment design. In this article, we will describe general methods to acquire quality images for mouse phenotyping using a system that images mice concurrently in shielded transmit/receive radio frequency (RF) coils in a common magnet (Bock et al., 2003). We focus particularly on anatomical phenotyping, an important and accessible application that has shown a high potential for impact in many mouse models at our imaging centre. Before we can provide the detailed steps to acquire such images, there are important practical considerations for both in vivo brain imaging (Dazai et al., 2004) and ex vivo brain imaging (Spring et al., 2007) that should be noted. These are discussed below.

Magnetic resonance imaging (MRI) has become an increasingly popular tool for examining the phenotype of genetically altered mice. This article illustrates the methods necessary to achieve high-throughput phenotyping of genetically altered mice using multiple-mouse MRI.

Multiple-topo Imaging neuroanatomici Risonanza Magnetica

The field of mouse phenotyping with magnetic resonance imaging (MRI) is rapidly growing, motivated by the need for improved tools for characterizing and ...

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Neuroscienze

Live Imaging of Dorsal Root Axons after Rhizotomy

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

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

Imaging in diretta degli assoni spinali dopo rizotomia

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

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 ...

Live Imaging of Mitosis in the Developing Mouse Embryonic Cortex

Although of short duration, mitosis is a complex and dynamic multi-step process fundamental for development of organs including the brain. In the developing cerebral cortex, abnormal mitosis of neural progenitors can cause defects in brain size and function. Hence, there is a critical need for tools to understand the mechanisms of neural progenitor mitosis. Cortical development in rodents is an outstanding model for studying this process. Neural progenitor mitosis is commonly examined in fixed brain sections. This protocol will describe in detail an approach for live imaging of mitosis in ex vivo embryonic brain slices. We will describe the critical steps for this procedure, which include: brain extraction, brain embedding, vibratome sectioning of brain slices, staining and culturing of slices, and time-lapse imaging. We will then demonstrate and describe in detail how to perform post-acquisition analysis of mitosis. We include representative results from this assay using the vital dye Syto11, transgenic mice (histone H2B-EGFP and centrin-EGFP), and in utero electroporation (mCherry-&#945;-tubulin). We will discuss how this procedure can be best optimized and how it can be modified for study of genetic regulation of mitosis. Live imaging of mitosis in brain slices is a flexible approach to assess the impact of age, anatomy, and genetic perturbation in a controlled environment, and to generate a large amount of data with high temporal and spatial resolution. Hence this protocol will complement existing tools for analysis of neural progenitor mitosis.

Neural progenitor mitosis is a critical parameter of neurogenesis. Much of our understanding of neural progenitor mitosis is based on analysis of fixed tissue. Live imaging in embryonic brain slices is a versatile technique to assess mitosis with high temporal and spatial resolution in a controlled environment.

Immagini dal vivo della mitosi in via di sviluppo embrionali di topo Cortex

Although of short duration, mitosis is a complex and dynamic multi-step process fundamental for development of organs including the brain. In the ...

Two-Photon in vivo Imaging of Dendritic Spines in the Mouse Cortex Using a Thinned-skull Preparation

In the mammalian cortex, neurons form extremely complicated networks and exchange information at synapses. Changes in synaptic strength, as well as addition/removal of synapses, occur in an experience-dependent manner, providing the structural foundation of neuronal plasticity. As postsynaptic components of the most excitatory synapses in the cortex, dendritic spines are considered to be a good proxy of synapses. Taking advantages of mouse genetics and fluorescent labeling techniques, individual neurons and their synaptic structures can be labeled in the intact brain. Here we introduce a transcranial imaging protocol using two-photon laser scanning microscopy to follow fluorescently labeled postsynaptic dendritic spines over time in vivo. This protocol utilizes a thinned-skull preparation, which keeps the skull intact and avoids inflammatory effects caused by exposure of the meninges and the cortex. Therefore, images can be acquired immediately after surgery is performed. The experimental procedure can be performed repetitively over various time intervals ranging from hours to years. The application of this preparation can also be expanded to investigate different cortical regions and layers, as well as other cell types, under physiological and pathological conditions.

Two-Photon in vivo Imaging of Dendritic Spines in the Mouse Cortex Using a Thinned-skull Preparation

Time-lapse imaging in the living animal provides valuable information on structural reorganization in the intact brain. Here, we introduce a thinned-skull preparation that allows transcranial imaging of fluorescently labeled synaptic structures in the living mouse cortex by two-photon microscopy.

Two-Photon<em&gt; In vivo</em&gt; Imaging di spine dendritiche nella corteccia mouse Uso un teschio Diluito-Preparazione

In the mammalian cortex, neurons form extremely complicated networks and exchange information at synapses. Changes in synaptic strength, as well as ...

Ex Vivo Imaging of Postnatal Cerebellar Granule Cell Migration Using Confocal Macroscopy

During postnatal development, immature granule cells (excitatory interneurons) exhibit tangential migration in the external granular layer, and then radial migration in the molecular layer and the Purkinje cell layer to reach the internal granular layer of the cerebellar cortex. Default in migratory processes induces either cell death or misplacement of the neurons, leading to deficits in diverse cerebellar functions. Centripetal granule cell migration involves several mechanisms, such as chemotaxis and extracellular matrix degradation, to guide the cells towards their final position, but the factors that regulate cell migration in each cortical layer are only partially known. In our method, acute cerebellar slices are prepared from P10 rats, granule cells are labeled with a fluorescent cytoplasmic marker and tissues are cultured on membrane inserts from 4 to 10 hr before starting real-time monitoring of cell migration by confocal macroscopy at 37 &#176;C in the presence of CO2. During their migration in the different cortical layers of the cerebellum, granule cells can be exposed to neuropeptide agonists or antagonists, protease inhibitors, blockers of intracellular effectors or even toxic substances such as alcohol or methylmercury to investigate their possible role in the regulation of neuronal migration.

Ex Vivo Imaging of Postnatal Cerebellar Granule Cell Migration Using Confocal Macroscopy

During postnatal cerebellum development, immature granule cells originating from the germinal zone exhibit distinct modalities of migration to reach their final destination and to establish neuronal networks. This protocol describes the preparation of cerebellar slices and the confocal macroscopic approach used to investigate the factors that regulate neuronal migration.

Ex Vivo Imaging di postnatale cerebellare granuli migrazione cellulare Utilizzando confocale macroscopia

During postnatal development, immature granule cells (excitatory interneurons) exhibit tangential migration in the external granular layer, and then ...

Simultaneous ex vivo Functional Testing of Two Retinas by in vivo Electroretinogram System

An In vivo electroretinogram (ERG) signal is composed of several overlapping components originating from different retinal cell types, as well as noise from extra-retinal sources. Ex vivo ERG provides an efficient method to dissect the function of retinal cells directly from an intact isolated retina of animals or donor eyes. In addition, ex vivo ERG can be used to test the efficacy and safety of potential therapeutic agents on retina tissue from animals or humans. We show here how commercially available in vivo ERG systems can be used to conduct ex vivo ERG recordings from isolated mouse retinas. We combine the light stimulation, electronic and heating units of a standard in vivo system with custom-designed specimen holder, gravity-controlled perfusion system and electromagnetic noise shielding to record low-noise ex vivo ERG signals simultaneously from two retinas with the acquisition software included in commercial in vivo systems. Further, we demonstrate how to use this method in combination with pharmacological treatments that remove specific ERG components in order to dissect the function of certain retinal cell types.

Simultaneous ex vivo Functional Testing of Two Retinas by in vivo Electroretinogram System

Ex vivo ERG can be used to record electrical activity of retinal cells directly from isolated intact retinas of animals or humans. We demonstrate here how common in vivo ERG systems can be adapted for ex vivo ERG recordings in order to dissect the electrical activity of retinal cells.

Simultaneo<em&gt; Ex vivo</em&gt; Test funzionale di due retine per<em&gt; In vivo</em&gt; Sistema Elettroretinogramma

An In vivo electroretinogram (ERG) signal is composed of several overlapping components originating from different retinal cell types, as well as noise ...

Live Imaging Followed by Single Cell Tracking to Monitor Cell Biology and the Lineage Progression of Multiple Neural Populations

Understanding the mechanisms that control critical biological events of neural cell populations, such as proliferation, differentiation, or cell fate decisions, will be crucial to design therapeutic strategies for many diseases affecting the nervous system. Current methods to track cell populations rely on their final outcomes in still images and they generally fail to provide sufficient temporal resolution to identify behavioral features in single cells. Moreover, variations in cell death, behavioral heterogeneity within a cell population, dilution, spreading, or the low efficiency of the markers used to analyze cells are all important handicaps that will lead to incomplete or incorrect read-outs of the results. Conversely, performing live imaging and single cell tracking under appropriate conditions represents a powerful tool to monitor each of these events. Here, a time-lapse video-microscopy protocol, followed by post-processing, is described to track neural populations with single cell resolution, employing specific software. The methods described enable researchers to address essential questions regarding the cell biology and lineage progression of distinct neural populations.

A robust protocol to monitor neural populations by time-lapse video-microscopy followed by software-based post-processing is described. This method represents a powerful tool to identify biological events in a selected population during live imaging experiments.

Seguita dalla singola cellula di rilevamento a Monitor biologia cellulare e la progressione di lignaggio di popolazioni neurali Multiple immagini dal vivo

Understanding the mechanisms that control critical biological events of neural cell populations, such as proliferation, differentiation, or cell fate ...

Single-cell Resolution Fluorescence Live Imaging of Drosophila Circadian Clocks in Larval Brain Culture

The circadian pacemaker circuit orchestrates rhythmic behavioral and physiological outputs coordinated with environmental cues, such as day/night cycles. The molecular clock within each pacemaker neuron generates circadian rhythms in gene expression, which underlie the rhythmic neuronal functions essential to the operation of the circuit. Investigation of the properties of the individual molecular oscillators in different subclasses of pacemaker neurons and their interaction with neuronal signaling yields a better understanding of the circadian pacemaker circuit. Here, we present a time-lapse fluorescent microscopy approach developed to monitor the molecular clockwork in clock neurons of cultured Drosophila larval brain. This method allows the multi-day recording of the rhythms of genetically encoded fluorescent circadian reporters at single-cell resolution. This setup can be combined with pharmacological manipulations to closely analyze real-time response of the molecular clock to various compounds. Beyond circadian rhythms, this multipurpose method in combination with powerful Drosophila genetic techniques offers the possibility to study diverse neuronal or molecular processes in live brain tissue.

Single-cell Resolution Fluorescence Live Imaging of Drosophila Circadian Clocks in Larval Brain Culture

The goal of this protocol is to establish ex vivo Drosophila larval brain culture optimized to monitor circadian molecular rhythms with long-term fluorescence time-lapse imaging. The application of this method to pharmacological assays is also discussed.

Cella singola risoluzione fluorescenza Live Imaging di Drosophila orologi circadiani nel cervello larvale cultura

The circadian pacemaker circuit orchestrates rhythmic behavioral and physiological outputs coordinated with environmental cues, such as day/night cycles. ...

Ex Vivo Imaging of Cell-specific Calcium Signaling at the Tripartite Synapse of the Mouse Diaphragm

The electrical activity of cells in tissues can be monitored by electrophysiological techniques, but these are usually limited to the analysis of individual cells. Since an increase of intracellular calcium (Ca2+) in the cytosol often occurs because of the electrical activity, or in response to a myriad of other stimuli, this process can be monitored by the imaging of cells loaded with fluorescent calcium-sensitive dyes.&#160; However, it is difficult to image this response in an individual cell type within whole tissue because these dyes are taken up by all cell types within the tissue. In contrast, genetically encoded calcium indicators (GECIs) can be expressed by an individual cell type and fluoresce in response to an increase of intracellular Ca2+, thus permitting the imaging of Ca2+ signaling in entire populations of individual cell types. Here, we apply the use of the GECIs GCaMP3/6 to the mouse neuromuscular junction, a tripartite synapse between motor neurons, skeletal muscle, and terminal/perisynaptic Schwann cells. We demonstrate the utility of this technique in classic ex vivo tissue preparations. Using an optical splitter, we perform dual-wavelength imaging of dynamic Ca2+ signals and a static label of the neuromuscular junction (NMJ) in an approach that could be easily adapted to monitor two cell-specific GECI or genetically encoded voltage indicators (GEVI) simultaneously. Finally, we discuss the routines used to capture spatial maps of fluorescence intensity. Together, these optical, transgenic, and analytic techniques can be employed to study the biological activity of distinct cell subpopulations at the NMJ in a wide variety of contexts.

Ex Vivo Imaging of Cell-specific Calcium Signaling at the Tripartite Synapse of the Mouse Diaphragm

Here we present a protocol to image calcium signaling in populations of individual cell types at the murine neuromuscular junction.