Questo lavoro è supportato dal NIH concedere NS065183 e fondi di start-up della Facoltà di Medicina di Rutgers Robert Wood Johnson.

1. Preparazione Rat astrociti Cultura per Media condizionata e astrociti-neuroni co-colture. <ol><li> Preparare buffer di dissezione (BSS, vedi Tabella 1 per ricetta) e conservare a 4 ° C fino al momento dell&#39;uso. </li><li> Anestetizzare cuccioli di ratto neonatale (P0-P2) con isoflurano in un bicchiere da 500 ml. </li><li> Quando cuccioli sono immobili, spruzzare con il 70% di etanolo e decapitare. </li><li> Rimuovere il cervello. <ol><li> Tenere la testa saldamente con un paio di Dumont # 5 pinze e usare le forbici pregiati per fare un&#39;incisione mediana attraverso la pelle e il cranio. </li><li> Esporre il cervello, riflettendo il cranio ai lati, e rimuovere il cervello in un piatto contenente freddo BSS. </li></ol></li><li> Separare gli emisferi cerebrali dal diencefalo e il tronco cerebrale in un ambito di dissezione. Rimuovere con cura tutte le meningi stabilizzando il tessuto con un paio di pinze e tirando delicatamente le meningi con un altro paio di pinze. </li><li> Raccogliere tutti i emisferin un 60 millimetri piatto. Utilizzando piccole forbici, tessuti trita più finemente possibile. Poi trasferire il tessuto tritato in una provetta conica da 50 ml. </li><li> Aggiungere 1,5 ml di 1% DNasi I e 1,5 ml di 2,5% tripsina e 12 ml di BSS (volume totale di 15 ml) al cervello. Incubare in un bagno d&#39;acqua per 15 minuti a 37 ° C. Per garantire una buona miscelazione, il tubo viene agitato a mano ogni 5 min. </li><li> Trasferire il surnatante attraverso un filtro 70 micron cella su un nuovo tubo conico da 50 ml. Aggiungere 3 ml FBS a questo surnatante. </li><li> Per i pezzi rimanenti, aggiungere 13,5 ml di BSS e 1,5 ml 2,5% tripsina e incubare nel bagnomaria agitazione per altri 15 min. </li><li> Trasferire il supernatante residuo attraverso il filtro cella e si combinano con il supernatante dal passo 1,8. </li><li> Centrifugare a 1000 rpm per 5 minuti per far sedimentare le cellule. </li><li> Risospendere pellet in 5 ml di media gliali. Surnatante può essere nuovamente centrifugato per far sedimentare le cellule rimanenti. </li><li> Contare le cellule utilizzando un emocitometro. </li><li> Piatto cells ad una densità di 1 x 10 7 ogni 150 cm 2 matraccio. </li><li> Cambiare media per mezzi freschi gliali il giorno dopo la placcatura. Successivamente, mangimi cellule due volte alla settimana con i media gliale. </li><li> Quando le cellule hanno raggiunto&gt; 80% di confluenza (circa 10 giorni dopo placcatura), congelare le cellule dal siero di cavallo 90% e 10% DMSO e mantenere scorte in azoto liquido. Le cellule sono congelati a 2 x 10 6 per flaconcino. Circa 5 fiale possono essere congelati da ciascun flacone. </li><li> Circa 10-14 giorni prima di impostare la cultura dell&#39;ippocampo, cellule gliali sono placcati dalle scorte congelate. Noi di solito piatto di cinque piastre da 6 pozzetti, il che è sufficiente a sostenere la crescita di 90 vetrini di neuroni dell&#39;ippocampo (tre coprioggetto 15 millimetri rotondi per pozzetto). Abbiamo anche piastra ulteriori otto a dieci 60 millimetri piatti a base di cellule gliali, che viene utilizzato per i media condizionata N2.1 per la trasfezione. Il giorno prima colture neuronali, cellule dovrebbe essere alimentato con i media NB27. Gli astrociti dovrebbero idealmente essere&gt; 90% confluenti al secoloè il punto. Troviamo che il congelamento riduce notevolmente il numero di microglia nelle culture astrogliali. Dal momento che una maggiore neurotossicità si osserva quando la microglia è presente nelle culture astrogliali, usiamo sempre la cultura astrogliale preparato da scorte congelate per co-coltura con i neuroni. </li></ol> 2. Cultura neuronale <ol><li> Pulire i vetrini per primo risciacquo in acqua MilliQ 2x. Essi vengono quindi immersi in acido nitrico concentrato per 24 ore, e risciacquati con acqua milliQ per almeno cinque volte per un totale di 2 ore. Coprioggetto vengono essiccati e sterilizzati mediante cottura in un forno a 225 ° C per 6 ore. </li><li> Trasferimento coprioggetto di 60 millimetri piatti dopo la sterilizzazione. Posizionare quattro punti di paraffina sterile vicino al bordo esterno di ogni coprioggetto per mantenere separati i neuroni da cellule gliali durante co-coltura. </li><li> Coprioggetto cappotto con 1 mg / ml di poli-L-lisina in 0.1 M tampone borato pernottamento a 37 ° C incubatore. </li><li> Il giorno dopo, lavare vetrini due volte in m sterileilliQ acqua per almeno 15 minuti ciascuno. Essi vengono poi incubate durante la notte nei media placcatura in 37 ° C incubatore. </li><li> Euthanize ratto gravide (E18) da anestesia isoflurano seguita da pneumotorace, e eutanasia topi embrionali per decapitazione. Rimuovere il cervello e sezionare i emisferi cerebrali come descritto sopra. </li><li> Sezionare il ippocampi dall&#39;emisfero cerebrale. Mettere tutti ippocampi in una provetta conica da 15 ml, e digerire con tripsina 0,25% (0,5 ml 2,5% tripsina, 4,5 ml BSS) a 37 ℃ per 15 min. </li><li> Ippocampi digeriti vengono risciacquati in BSS 3x per 5 minuti ciascuno. Vengono poi triturato con una pipetta Pasteur di vetro, e la densità cellulare è determinato utilizzando un emocitometro. I neuroni sono poi seminate ad una densità di 2 x 10 5 cellule ogni 60 mm senza coperchio. </li><li> Circa 2-4 ore dopo la placcatura, il trasferimento coprioggetto con i neuroni collegati ai piatti contenenti cellule astrogliali, con i neuroni rivolto verso la glia. A DIV3, aggiungere citosina arabinoside alcellule ad una concentrazione finale di 5 mM per fermare glia proliferazione. </li></ol> 3. Calcio Transfezione <ol><li> Supporti Condizione N2.1 sulla glia il giorno prima trasfezione. </li><li> Il giorno della trasfezione, adottare mezzi N2.1 condizionata fuori della glia e trasferire in un nuovo piatto. Trasferimento coprioggetto con i neuroni nel supporto N2.1 condizionato. Lasciare equilibrare in incubatrice per 10-30 min. </li><li> Per una serie di provette sterili, combinare 1-4 mg di DNA, 12,5 ml di 2 M CaCl 2 e H 2 O sterile per un volume totale di 100 microlitri. Per un secondo gruppo di tubi, aggiungere 100 ml di 2x HBS. </li><li> Aggiungere ⅛ volume di 2x HBS (12,5 mL) alla volta alla provetta contenente la miscela CaCl 2 / DNA, vortex per pochi secondi ogni volta. Lasciare le provette a sedere per 15 min. </li><li> Dopo 15 minuti di incubazione, aggiungere goccia a goccia la miscela di trasfezione per le cellule. Incubare per 1-1,5 ore. Uno strato di precipitati sabbia come dovrebbe essere visibilesotto il microscopio usando un obiettivo 10X. </li><li> Dopo l&#39;incubazione, lavare vetrini due volte con caldo tampone di lavaggio HBS. </li><li> Coprioggetti Ritorno a piatti originali con glia, aggiungere acido kynurenic ad una concentrazione finale di 0,5 mm. </li><li> Neuroni trasfettati possono essere esposte in diretta o trattati per immunocitochimica già a partire dal giorno successivo. I neuroni possono sopravvivere fino a tre settimane dopo la trasfezione. </li></ol>

<ol>
	<li>Karra, D., Dahm, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transfection+techniques+for+neuronal+cells.">Transfection techniques for neuronal cells.</a> J. Neurosci. 30, 6171-6177 (2010).</li><li>Zeitelhofer, 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=High-efficiency+transfection+of+mammalian+neurons+via+nucleofection.">High-efficiency transfection of mammalian neurons via nucleofection.</a> Nat. Protoc. 2, 1692-1704 (2007).</li><li>Janas, J., Skowronski, J., Van Aelst, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lentiviral+delivery+of+RNAi+in+hippocampal+neurons.">Lentiviral delivery of RNAi in hippocampal neurons.</a> Method Enzymol. 406, 593-605 (2006).</li><li>Graham, F. L., vander Eb, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+technique+for+the+assay+of+infectivity+of+human+adenovirus+5+DNA.">A new technique for the assay of infectivity of human adenovirus 5 DNA.</a> Virology. 52, 456-467 (1973).</li><li>Craig, A. M., Banker, G. a. G. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transfecting+cultured+neurons.">Transfecting cultured neurons.</a> Culturing Nerve Cells. , (1998).</li><li>Alavian, K. N., 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=Bcl-xL+regulates+metabolic+efficiency+of+neurons+through+interaction+with+the+mitochondrial+F1FO+ATP+synthase.">Bcl-xL regulates metabolic efficiency of neurons through interaction with the mitochondrial F1FO ATP synthase.</a> Nat. Cell Biol. 13, 1224-1233 (2011).</li><li>Zhang, Y., 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=Modulation+of+synaptic+function+by+VAC14,+a+protein+that+regulates+the+phosphoinositides+PI(3,5)P(2)+and+PI(5)P.">Modulation of synaptic function by VAC14, a protein that regulates the phosphoinositides PI(3,5)P(2) and PI(5)P.</a> EMBO J. 31, 3442-3456 (2012).</li><li>Dudek, H., Ghosh, A., Greenberg, 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=Calcium+phosphate+transfection+of+DNA+into+neurons+in+primary+culture.">Calcium phosphate transfection of DNA into neurons in primary culture.</a> Curr. Protoc. Neurosci. Chapter 3, Unit 3 11 (2001).</li><li>Goslin, K. A. H., Banker, G., Banker, G. a. G. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rat+Hippocampal+Neurons+in+Low-Density+Culture.">Rat Hippocampal Neurons in Low-Density Culture.</a> Culturing Nerve Cells. , (1998).</li><li>Kohrmann, 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=Fast,+convenient,+and+effective+method+to+transiently+transfect+primary+hippocampal+neurons.">Fast, convenient, and effective method to transiently transfect primary hippocampal neurons.</a> J. Neurosci. Res. 58, 831-835 (1999).</li><li>Jiang, M., Chen, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+Ca2+-phosphate+transfection+efficiency+in+low-density+neuronal+cultures.">High Ca2+-phosphate transfection efficiency in low-density neuronal cultures.</a> Nat. Protoc. 1, 695-700 (2006).</li><li>Goetze, B., Grunewald, B., Baldassa, S., Kiebler, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemically+controlled+formation+of+a+DNA/calcium+phosphate+coprecipitate:+application+for+transfection+of+mature+hippocampal+neurons.">Chemically controlled formation of a DNA/calcium phosphate coprecipitate: application for transfection of mature hippocampal neurons.</a> J. Neurobiol. 60, 517-525 (2004).</li></ol>

Nessun conflitto di interesse dichiarati.

Ci sono diversi parametri chiave che devono essere attentamente controllata per trasfezioni costantemente successo 10,11. Il parametro più critico per il fosfato di calcio trasfezione è il valore di pH 2x HBS, che nelle nostre mani solito varia tra 7,10-7,15. Si consiglia di fare tre lotti di titoli con valori di pH in 0.05 incrementi per spiegare la differenza tra pH-metri. In alternativa, il kit di transfezione mammiferi Clontech fornisce 2x HBS che produce costantemente buona efficienza. Tenere presente ...

Neuroni primari sono uno dei tipi di cellule più difficili da trasfettare come sono postmitotico e sono molto sensibili alle variazioni microambientali. Ci sono quattro tipi comunemente usati di metodi per l&#39;espressione di geni esogeni e RNA breve tornante (shRNAs) in queste cellule 1. Ognuno ha i suoi vantaggi e svantaggi. Ad esempio, elettroporazione viene di solito effettuata su neuroni appena isolate 2, come le cellule devono essere trasferiti in cuvette per trasfezione. Infezione da virus di solito può raggiungere un grado elevato di efficienza 3, ma è sempre rischiosa per gli operatori-intensità di lavoro. Molti reagenti di transfezione lipidi mediata sono disponibili in commercio, con vari gradi di successo nei neuroni e diversi livelli di citotossicità. Fosfato di calcio trasfezione rappresenta un metodo conveniente ed economico per l&#39;introduzione di geni estranei in neuroni. Il metodo è stato usato per la prima a introdurre adenovirus DNA in cel mammiferiLS di Graham e Van Der Eb (1973) 4. La trasfezione è stata eseguita miscelando cloruro di calcio con il DNA ricombinante in un tampone fosfato. Questo permette la formazione di fosfato di DNA / calcio precipitati che, quando gradualmente lasciato cadere su un monostrato di cellule, aderire alla superficie cellulare, sono assorbite per endocitosi e finalmente entrare nel nucleo 5. Questo processo porterebbe alla espressione di geni estranei introdotti nella cellula bersaglio. Tipiche efficienze di fosfato di calcio serie trasfezione tra il 0.5-5% 6-8. Tuttavia, con un&#39;attenta ottimizzazione e coerente attuazione del protocollo sperimentale, è possibile raggiungere una efficienza di trasfezione di quasi il 50%. Qui descriviamo il nostro protocollo dettagliato per fosfato di calcio trasfezione di neuroni primari, che sono co-coltivate con le cellule astrogliali in un formato panino 9.

<table border="0" cellpadding="0" cellspacing="0" width="879">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="24">
			<td height="24" style="height:24px;width:284px;">Dumont #5 forceps</td>
			<td style="width:207px;">Fine Science Tools</td>
			<td style="width:119px;">11251-20</td>
			<td style="width:269px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:284px;">Fine scissors</td>
			<td style="width:207px;">Fine Science Tools</td>
			<td style="width:119px;">14090-09</td>
			<td>straight / sharp 8.5 cm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:284px;">Vannas-Tubinger spring scissors</td>
			<td style="width:207px;">Fine Science Tools</td>
			<td style="width:119px;">15008-08</td>
			<td>angled / sharp / 8.5 cm / 5 mm cutting edge</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:284px;">Standard pattern forceps</td>
			<td style="width:207px;">Fine Science Tools</td>
			<td style="width:119px;">11000-16</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:284px;">Student surgical scissors</td>
			<td style="width:207px;">Fine Science Tools</td>
			<td style="width:119px;">91401-14</td>
			<td>blunt / 14.5 cm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:284px;">Spring scissors</td>
			<td style="width:207px;">Fine Science Tools</td>
			<td style="width:119px;">15006-09</td>
			<td>angled to side / 9 cm / 10 mm cutting edge</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:284px;">Isoflurane</td>
			<td style="width:207px;">Webster Veterinary</td>
			<td style="width:119px;">14043-225-06</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:284px;">Poly-L-lysine</td>
			<td>Sigma</td>
			<td style="width:119px;">P2636</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">MEM</td>
			<td>Sigma</td>
			<td>M2279</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:284px;">100 mM Sodium pyruvate</td>
			<td style="width:207px;">Sigma</td>
			<td style="width:119px;">S8636</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:284px;">Glucose</td>
			<td style="width:207px;">Sigma</td>
			<td style="width:119px;">G8270</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">10x HBSS</td>
			<td>Sigma</td>
			<td>H4385</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:284px;">1 M HEPES, pH 7.3</td>
			<td>Gibco/Invitrogen</td>
			<td>15630-080</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">GlutaMAX</td>
			<td>Gibco/Invitrogen</td>
			<td>35050-061</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Neurobasal Media</td>
			<td>Gibco/Invitrogen</td>
			<td>21130-049</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">B27 Supplement (50x)</td>
			<td>Gibco/Invitrogen</td>
			<td>17504-044</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">N2 Supplement</td>
			<td>Gibco/Invitrogen</td>
			<td>17502-048</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ovalbumin</td>
			<td style="width:207px;">Sigma</td>
			<td style="width:119px;">A5503</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Penicillin/Streptomycin</td>
			<td>Gibco/Invitrogen</td>
			<td style="width:119px;">15070-063</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:284px;">2.5% Trypsin</td>
			<td>Gibco/Invitrogen</td>
			<td style="width:119px;">15090-046</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:284px;">DNase I</td>
			<td style="width:207px;">Sigma</td>
			<td style="width:119px;">DN-25</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:284px;">Cytosine arabinoside</td>
			<td style="width:207px;">Calbiochem/EMD Millipore</td>
			<td align="right" style="width:119px;">251010</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:284px;">Kynurenic acid</td>
			<td style="width:207px;">Sigma</td>
			<td style="width:119px;">K3375</td>
			<td></td>
		</tr>
	</tbody>
</table>

calcium phosphate transfection of primary hippocampal neurons

Precipitazione di fosfato di calcio è un metodo conveniente ed economico per la trasfezione di cellule in coltura. Con ottimizzazione, è possibile usare questo metodo su cellule di difficile trasfezione come neuroni primari. Qui descriviamo il nostro protocollo dettagliato per fosfato di calcio trasfezione di neuroni dell&#39;ippocampo co-coltivate con le cellule astrogliali.

Quando i diversi parametri della trasfezione sono ottimizzati e accuratamente controllati da esperimento per sperimentare, è possibile avere efficienze di trasfezione fino al 50%. Figura 1 mostra un campo di neuroni che sono trasfettate con GFP su DIV4. Il campo contiene un totale di 28 neuroni, tra cui 16 sono state trasfettate. Ciò rappresenta un rendimento di oltre il 50%. Un campione di altri campi sullo stesso vetrino mostra l&#39;efficienza complessiva è di circa il 50% (dati non mostrati). Con...

Watch this Scientific Journal Video about Calcium Phosphate Transfection of Primary Hippocampal Neurons at JoVE.com

Calcium Phosphate Transfection of Primary Hippocampal Neurons

Fosfato di calcio trasfezione di primaria neuroni dell&#39;ippocampo

Calcium phosphate precipitation is a convenient and economical method for transfection of cultured cells. With optimization, it is possible to use this ...

calcium-phosphate-transfection-of-primary-hippocampal-neurons

Research

JoVE Journal

Neuroscience

25.1K Views.  Rutgers University.  Precipitazione di fosfato di calcio è un metodo conveniente ed economico per la trasfezione di cellule in coltura. Con ottimizzazione, è possibile usare questo metodo su cellule di difficile trasfezione come neuroni primari. Qui descriviamo il nostro protocollo dettagliato per fosfato di calcio trasfezione di neuroni dell'ippocampo co-coltivate con le cellule astrogliali. 

Video: Calcium Phosphate Transfection of Primary Hippocampal Neurons

Nucleofection and Primary Culture of Embryonic Mouse Hippocampal and Cortical Neurons

Hippocampal and cortical neurons have been used extensively to study central nervous system (CNS) neuronal polarization, axon/dendrite outgrowth, and synapse formation and function. An advantage of culturing these neurons is that they readily polarize, forming distinctive axons and dendrites, on a two dimensional substrate at very low densities. This property has made them extremely useful for determining many aspects of neuronal development. Furthermore, by providing glial conditioning for these neurons they will continue to develop, forming functional synaptic connections and surviving for several months in culture. In this protocol we outline a technique to dissect, culture and transfect embryonic mouse hippocampal and cortical neurons. Transfection is accomplished by electroporating DNA into the neurons before plating via nucleofection. This protocol has the advantage of expressing fluorescently-tagged fusion proteins early in development (~4-8hrs after plating) to study the dynamics and function of proteins during polarization, axon outgrowth and branching. We have also discovered that this single transfection before plating maintains fluorescently-tagged fusion protein expression at levels appropriate for imaging throughout the lifetime of the neuron (&gt; 2 months in culture). Thus, this methodology is useful for studying protein localization and function throughout CNS development with little or no disruption of neuronal function.

This protocol outlines the steps required to dissect, transfect via electroporation and culture mouse hippocampal and cortical neurons. Short-term cultures may be used for studies of axon outgrowth and guidance, while long-term cultures can be used for studies of synaptogenesis and dendritic spine analysis.

Nucleofection e cultura primaria di neuroni embrionali di topo ippocampale e corticale

Hippocampal and cortical neurons have been used extensively to study central nervous system (CNS) neuronal polarization, axon/dendrite outgrowth, and ...

Ricerca

Neuroscienze

Imaging Dendritic Spines of Rat Primary Hippocampal Neurons using Structured Illumination Microscopy

Dendritic spines are protrusions emerging from the dendrite of a neuron and represent the primary postsynaptic targets of excitatory inputs in the brain. Technological advances have identified these structures as key elements in neuron connectivity and synaptic plasticity. The quantitative analysis of spine morphology using light microscopy remains an essential problem due to technical limitations associated with light's intrinsic refraction limit. Dendritic spines can be readily identified by confocal laser-scanning fluorescence microscopy. However, measuring subtle changes in the shape and size of spines is difficult because spine dimensions other than length are usually smaller than conventional optical resolution fixed by light microscopy's theoretical resolution limit of 200 nm.
Several recently developed super resolution techniques have been used to image cellular structures smaller than the 200 nm, including dendritic spines. These techniques are based on classical far-field operations and therefore allow the use of existing sample preparation methods and to image beyond the surface of a specimen. Described here is a working protocol to apply super resolution structured illumination microscopy (SIM) to the imaging of dendritic spines in primary hippocampal neuron cultures. Possible applications of SIM overlap with those of confocal microscopy. However, the two techniques present different applicability. SIM offers higher effective lateral resolution, while confocal microscopy, due to the usage of a physical pinhole, achieves resolution improvement at the expense of removal of out of focus light. In this protocol, primary neurons are cultured on glass coverslips using a standard protocol, transfected with DNA plasmids encoding fluorescent proteins and imaged using SIM. The whole protocol described herein takes approximately 2 weeks, because dendritic spines are imaged after 16-17 days in vitro, when dendritic development is optimal. After completion of the protocol, dendritic spines can be reconstructed in 3D from series of SIM image stacks using specialized software.

This article describes a working protocol to image dendritic spines from hippocampal neurons in vitro using Structured Illumination Microscopy (SIM). Super-resolution microscopy using SIM provides image resolution significantly beyond the light diffraction limit in all three spatial dimensions, allowing the imaging of individual dendritic spines with improved detail.

Imaging spine dendritiche di Rat Primaria neuroni dell&#39;ippocampo utilizzando Structured Illumination Microscopy

Dendritic spines are protrusions emerging from the dendrite of a neuron and represent the primary postsynaptic targets of excitatory inputs in the brain. ...

Primary Culture of Mouse Dopaminergic Neurons

Dopaminergic neurons represent less than 1% of the total number of neurons in the brain. This low amount of neurons regulates important brain functions such as motor control, motivation, and working memory. Nigrostriatal dopaminergic neurons selectively degenerate in Parkinson&#39;s disease (PD). This progressive neuronal loss is unequivocally associated with the motors symptoms of the pathology (bradykinesia, resting tremor, and muscular rigidity). The main agent responsible of dopaminergic neuron degeneration is still unknown. However, these neurons appear to be extremely vulnerable in diverse conditions. Primary cultures constitute one of the most relevant models to investigate properties and characteristics of dopaminergic neurons. These cultures can be submitted to various stress agents that mimic PD pathology and to neuroprotective compounds in order to stop or slow down neuronal degeneration. The numerous transgenic mouse models of PD that have been generated during the last decade further increased the interest of researchers for dopaminergic neuron cultures. Here, the video protocol focuses on the delicate dissection of embryonic mouse brains. Precise excision of ventral mesencephalon is crucial to obtain neuronal cultures sufficiently rich in dopaminergic cells to allow subsequent studies. This protocol can be realized with embryonic transgenic mice and is suitable for immunofluorescence staining, quantitative PCR, second messenger quantification, or neuronal death/survival assessment.

Dopaminergic neurons play a vital regulatory role in the brain. Their loss is associated with Parkinson's disease. In this video, we show how to generate primary cultures of central dopaminergic neurons from embryonic mouse mesencephalon. Such cultures are useful to study the extreme vulnerability of these neurons to various stresses.

Cultura primario di topo neuroni dopaminergici

Dopaminergic neurons represent less than 1% of the total number of neurons in the brain. This low amount of neurons regulates important brain functions ...

Fluorescence and Bioluminescence Imaging of Subcellular Ca2+ in Aged Hippocampal Neurons

Susceptibility to neuron cell death associated to neurodegeneration and ischemia are exceedingly increased in the aged brain but mechanisms responsible are badly known. Excitotoxicity, a process believed to contribute to neuron damage induced by both insults, is mediated by activation of glutamate receptors that promotes Ca2+ influx and mitochondrial Ca2+ overload. A substantial change in intracellular Ca2+ homeostasis or remodeling of intracellular Ca2+ homeostasis may favor neuron damage in old neurons. For investigating Ca2+ remodeling in aging we have used live cell imaging in long-term cultures of rat hippocampal neurons that resemble in some aspects aged neurons in vivo. For this end, hippocampal cells are, in first place, freshly dispersed from new born rat hippocampi and plated on poli-D-lysine coated, glass coverslips. Then cultures are kept in controlled media for several days or several weeks for investigating young and old neurons, respectively. Second, cultured neurons are loaded with fura2 and subjected to measurements of cytosolic Ca2+ concentration using digital fluorescence ratio imaging. Third, cultured neurons are transfected with plasmids expressing a tandem of low-affinity aequorin and GFP targeted to mitochondria. After 24 hr, aequorin inside cells is reconstituted with coelenterazine and neurons are subjected to bioluminescence imaging for monitoring of mitochondrial Ca2+ concentration. This three-step procedure allows the monitoring of cytosolic and mitochondrial Ca2+ responses to relevant stimuli as for example the glutamate receptor agonist NMDA and compare whether these and other responses are influenced by aging. This procedure may yield new insights as to how aging influence cytosolic and mitochondrial Ca2+ responses to selected stimuli as well as the testing of selected drugs aimed at preventing neuron cell death in age-related diseases.

Fluorescence and Bioluminescence Imaging of Subcellular Ca2+ in Aged Hippocampal Neurons

Intracellular Ca2+ remodeling in aging may contribute to excitotoxicity and neuron damage, processes mediated by Ca2+ overload. We aimed at investigating Ca2+ remodeling in the aging brain using fluorescence and bioluminescence imaging of cytosolic and mitochondrial Ca2+ in long-term cultures of rat hippocampal neurons, a model of neuronal aging.

Fluorescenza e bioluminescenza di subcellulare Ca<sup&gt; 2+</sup&gt; In Aged neuroni dell&#39;ippocampo

Susceptibility to neuron cell death associated to neurodegeneration and ischemia are exceedingly increased in the aged brain but mechanisms responsible ...

Low-Density Primary Hippocampal Neuron Culture

The ability to probe the structure and physiology of individual nerve cells in culture is crucial to the study of neurobiology, and allows for flexibility in genetic and chemical manipulation of individual cells or defined networks. Such ease of manipulation is simpler in the reduced culture system when compared to the intact brain tissue. While many methods for the isolation and growth of these primary neurons exist, each has its own limitations. This protocol describes a method for culturing low-density and high-purity rodent embryonic hippocampal neurons on glass coverslips, which are then suspended over a monolayer of glial cells. This &#39;sandwich culture&#39; allows for exclusive long-term growth of a population of neurons while allowing for trophic support from the underlying glial monolayer. When neurons are of sufficient age or maturity level, the neuron coverslips can be flipped-out of the glial dish and used in imaging or functional assays. Neurons grown by this method typically survive for several weeks and develop extensive arbors, synaptic connections, and network properties.

This article describes the protocol for culturing low-density primary hippocampal neurons growing on glass coverslips inverted over a glial monolayer. The neuron and glial layers are separated by paraffin wax beads. The neurons grown by this method are suitable for high-resolution optical imaging and functional assays.

A bassa densità primaria ippocampale Cultura Neuron

The ability to probe the structure and physiology of individual nerve cells in culture is crucial to the study of neurobiology, and allows for flexibility ...

Measuring Synaptic Vesicle Endocytosis in Cultured Hippocampal Neurons

During endocytosis, fused synaptic vesicles are retrieved at nerve terminals, allowing for vesicle recycling and thus the maintenance of synaptic transmission during repetitive nerve firing. Impaired endocytosis in pathological conditions leads to decreases in synaptic strength and brain functions. Here, we describe methods used to measure synaptic vesicle endocytosis at the mammalian hippocampal synapse in neuronal culture. We monitored synaptic vesicle protein endocytosis by fusing a synaptic vesicular membrane protein, including synaptophysin and VAMP2/synaptobrevin, at the vesicular lumenal side, with pHluorin, a pH-sensitive green fluorescent protein that increases its fluorescence intensity as the pH increases. During exocytosis, vesicular lumen pH increases, whereas during endocytosis vesicular lumen pH is re-acidified. Thus, an increase of pHluorin fluorescence intensity indicates fusion, whereas a decrease indicates endocytosis of the labelled synaptic vesicle protein. In addition to using the pHluorin imaging method to record endocytosis, we monitored vesicular membrane endocytosis by electron microscopy (EM) measurements of Horseradish peroxidase (HRP) uptake by vesicles. Finally, we monitored the formation of nerve terminal membrane pits at various times after high potassium-induced depolarization. The time course of HRP uptake and membrane pit formation indicates the time course of endocytosis.

Synaptic vesicle endocytosis is detected by light microscopy of pHluorin fused with synaptic vesicle protein and by electron microscopy of vesicle uptake.

Endocitosi delle vescicole sinaptiche in colture di neuroni ippocampali di misura

During endocytosis, fused synaptic vesicles are retrieved at nerve terminals, allowing for vesicle recycling and thus the maintenance of synaptic ...

Generation of Neurospheres from Mixed Primary Hippocampal and Cortical Neurons Isolated from E14-E16 Sprague Dawley Rat Embryo

Primary neuron culture is an essential technique in the field of neuroscience. To gain deeper mechanistic insights into the brain, it is essential to have a robust in vitro model that can be exploited for various neurobiology studies. Though primary neuron cultures (i.e., long-term hippocampal cultures) have provided scientists with models, it does not yet represent the complexity of brain network completely. In the wake of these limitations, a new model has emerged using neurospheres, which bears a closer resemblance to the brain tissue. The present protocol describes the plating of high and low densities of mixed cortical and hippocampal neurons isolated from the embryo of embryonic day 14-16 Sprague Dawley rats. This allows for the generation of neurospheres and long-term primary neuron culture as two independent platforms to conduct further studies. This process is extremely simple and cost-effective, as it minimizes several steps and reagents previously deemed essential for neuron culture. This is a robust protocol with minimal requirements that can be performed with achievable results and further used for a diversity of studies related to neuroscience.

Presented here is a protocol for the spontaneous generation of neurospheres enriched in neural progenitor cells from high density plated neurons. During the same experiment, when neurons are plated at a lower density, the protocol also results in prolonged primary rat neuron cultures.

Generazione di neurosfere da neuroni ippocampali primari misti e corticali isolati da E14-E16 Sprague Dawley Rat Embryo

Primary neuron culture is an essential technique in the field of neuroscience. To gain deeper mechanistic insights into the brain, it is essential to have ...

Use of Primary Cultured Hippocampal Neurons to Study the Assembly of Axon Initial Segments

Neuronal axon initial segments (AIS) are sites of initiation of action potentials and have been extensively studied for their molecular structure, assembly and activity-dependent plasticity. Giant ankyrin-G, the master organizer of AIS, directly associates with membrane-spanning voltage gated sodium (VSVG) and potassium channels (KCNQ2/3), as well as 186 kDa neurofascin, a L1CAM cell adhesion molecule. Giant ankyrin-G also binds to and recruits cytoplasmic AIS molecules including beta-4-spectrin, and the microtubule-binding proteins, EB1/EB3 and Ndel1. Giant ankyrin-G is sufficient to rescue AIS formation in ankyrin-G deficient neurons. Ankyrin-G also includes a smaller 190 kDa isoform located at dendritic spines instead of the AIS, which is incapable of targeting to the AIS or rescuing the AIS in ankyrin-G-deficient neurons. Here, we described a protocol using cultured hippocampal neurons from ANK3-E22/23-flox mice, which, when transfected with Cre-BFP exhibit loss of all isoform of ankyrin-G and impair the formation of AIS. Combined a modified Banker glia/neuron co-culture system, we developed a method to transfect ankyrin-G null neurons with a 480 kDa ankyrin-G-GFP plasmid, which is sufficient to rescue the formation of AIS. We further employ a quantification method, developed by Salzer and colleagues to deal with variation in AIS distance from the neuronal cell bodies that occurs in hippocampal neuron cultures. This protocol allows quantitative studies of the de novo assembly and dynamic behavior of AIS.

Here, we described a protocol to quantitatively study the assembly and structure of the axon initial segments (AIS) of hippocampal neurons that lack pre-assembled AIS due to the absence of a giant ankyrin-G.

Uso di neuroni ippocampali coltivati primari per studiare l'assemblaggio dei segmenti iniziali di Axon

Neuronal axon initial segments (AIS) are sites of initiation of action potentials and have been extensively studied for their molecular structure, ...

Easy and Reproducible Low-Density Primary Culture using Frozen Stock of Embryonic Hippocampal Neurons

Neuronal culture is a valuable system for evaluating synaptic functions and drug screenings. In particular, a low-density culture of primary hippocampal neurons allows the study of individual neurons or subcellular components. We have shown subcellular protein localization within a neuron by immunocytochemistry, neuronal polarity, synaptic morphology, and its developmental change using a low-density primary hippocampal culture. Recently, ready-to-use frozen stocks of neurons have become commercially available. These frozen stocks of neurons reduce the time needed to prepare animal experiments and also contribute to the reduction of the number of animals used. Here, we introduce a reproducible low-density primary culture method using a 96-well plate. We used a commercially available frozen stock of neurons from the rat embryonic hippocampus. The neurons can be stably cultured long-term without media changes by reducing the growth of glial cells at particular timepoints. This high-throughput assay using low-density culture allows reproducible imaging-based evaluations of synaptic plasticity.

A ready-to-use frozen stock of neurons is a powerful tool for evaluating synaptic functions. Here, we introduce an easy low-density primary culture from frozen stock using a 96-well plate.

Coltura primaria a bassa densità facile e riproducibile utilizzando stock congelati di neuroni ippocampali embrionali

Neuronal culture is a valuable system for evaluating synaptic functions and drug screenings. In particular, a low-density culture of primary hippocampal ...

In Vivo Calcium Imaging of Neuronal Ensembles in Networks of Primary Sensory Neurons in Intact Dorsal Root Ganglia

Ca2+ imaging can be used as a proxy for cellular activity, including action potentials and various signaling mechanisms involving Ca2+ entry into the cytoplasm or the release of intracellular Ca2+ stores. Pirt-GCaMP3-based Ca2+ imaging of primary sensory neurons of the dorsal root ganglion (DRG) in mice offers the advantage of simultaneous measurement of a large number of cells. Up to 1,800 neurons can be monitored, allowing neuronal networks and somatosensory processes to be studied as an ensemble in their normal physiological context at a populational level in vivo. The large number of neurons monitored allows the detection of activity patterns that would be challenging to detect using other methods. Stimuli can be applied to the mouse hindpaw, allowing the direct effects of stimuli on the DRG neuron ensemble to be studied. The number of neurons producing Ca2+ transients as well as the amplitude of Ca2+ transients indicates sensitivity to specific sensory modalities. The diameter of neurons provides evidence of activated fiber types (non-noxious mechano vs. noxious pain fibers, A&#946;, A&#948;, and C fibers). Neurons expressing specific receptors can be genetically labeled with td-Tomato and specific Cre recombinases together with Pirt-GCaMP. Therefore, Pirt-GCaMP3 Ca2+ imaging of DRG provides a powerful tool and model for the analysis of specific sensory modalities and neuron subtypes acting as an ensemble at the populational level to study pain, itch, touch, and other somatosensory signals.

In Vivo Calcium Imaging of Neuronal Ensembles in Networks of Primary Sensory Neurons in Intact Dorsal Root Ganglia

This protocol describes the surgical exposure of the dorsal root ganglion (DRG) followed by GCaMP3 (genetically-encoded Ca2+ indicator; Green Fluorescent Protein-Calmodulin-M13 Protein 3) Ca2+ imaging of the neuronal ensembles using Pirt-GCaMP3 mice while applying a variety of stimuli to the ipsilateral hind paw.

In vivo Imaging del calcio di insiemi neuronali in reti di neuroni sensoriali primari nei gangli della radice dorsale intatti

Ca2+ imaging can be used as a proxy for cellular activity, including action potentials and various signaling mechanisms involving Ca2+ entry into the ...