Vorremmo ringraziare tutti i membri del Keller e dei Magie Labs presso l&#39;Università Quinnipiac per suggerimenti utili. In particolare, vorremmo ringraziare Barron L. Lincoln II per lo sviluppo di questo test di lesioni all&#39;interno del Keller Lab. Vorremmo inoltre ringraziare l&#39;Università di Quinnipiac College of Arts e Science Grant-In-Aid conferito a LC Keller.

1. Preparazione di reagenti e attrezzature <ol><li> Preparare 1x dissezione buffer (70 mM NaCl, 5 mM KCl, 0,02 mM CaCl 2, 20 mM MgCl 2, 10 mM NaHCO 3, 115 mM di saccarosio, trealosio 5 mM, HEPES 5 mM, pH 7.2). </li><li> Preparare una soluzione salina a base di fosfato (PBS). </li><li> Preparare 1x PBT utilizzando 1x PBS con 0.01% Triton X-100. </li><li> Preparare le piastre di agar succo di frutta. 14 In breve, mescolare 30 g di agar in 700 ml di H 2 O e autoclave. Sciogliere 0,5 g di metil paraben in 10 ml di etanolo e aggiungere la soluzione a 300 ml di concentrato di succo di frutta (uva o mela). Mescolare la concentrazione in soluzione agar autoclavata e versare nei coperchi di piatti da 10 mm x 35 mm Petri. NOTA: La premiera di potenza dell&#39;agrumi può essere acquistata anche da varie aziende (vedere tabelle dei materiali ). </li><li> Ottieni pinze di dimensione 5 che permettono di danneggiare meccanicamente le larve. </li><li> Utilizzare Drosophila standard CO 2 </sUb&gt; base dell&#39;anestesia. </li></ol> 2. Selezionare Drosophila Larvae <ol><li> Prendete un fiale o una bottiglia di Drosophila contenenti larve di terzo istante vagate che sono state coltivate a 25 ° C. </li><li> Selezionare dieci singoli 2 ° o 3 ° larve instar basate sull&#39;apparenza. Le larve di terze instari possono essere identificate dall&#39;aspetto di spirali anch&#39;esse ramificate, mentre le seconde larve di instar sono più piccole e presentano più spiracles anteriori. NOTA: le fasi Larval possono anche essere identificate mediante la temporizzazione. A 25 ° C, le larve secondarie appaiono approssimativamente 48 ore dopo la schiusa, e le larve di terzo istar molt circa 24 ore più tardi. Se interessati ad esaminare la neurodegenerazione presso la NMJ, le seconde larve instar devono essere ferite. </li></ol> 3. Preparazione delle larve Drosophila per lesioni meccaniche <ol><li> Prendete con attenzione le singole larve con le pinze o con un pennello, facendo attenzioneNon per comprimerlo comunque. </li><li> Posizionare direttamente 10 larve in un piatto di vetro contenente un freddo PBS o un tampone di dissezione per rimuovere eventuali detriti alimentari e decelerare la motilità del larvale. </li></ol> 4. lesioni meccaniche e trattamento di larve Drosophila <ol><li> Posizionare ogni singola larva su un apparecchio di anestesia di CO 2 . </li><li> Sotto un microscopio di dissezione, rotolare attentamente ogni larva sul loro lato dorsale per visualizzare i nervi segmentali attraverso la cuticola. </li><li> La dimensione di posizione 5 pende circa 1/2 a 2/3 lungo la lunghezza della larva partendo dai ganci della bocca. Una volta posizionato, pizzicare circa 1/3 della cuticola ventrale contenente i nervi segmentali con pinze di dimensioni 5. <ol><li> Per garantire che i nervi segmentali larvali siano feriti, applicare forza sufficiente a schiacciare i nervi segmentali ma lasciare intatta la cuticola. Per determinare la giusta quantità di forza, schiacciare 10 larve e assicurarsiIl tasso di mortalità dopo 5 h è inferiore al 50%. </li></ol></li><li> Dopo lesioni, trasferire con cura le larve in una piastra di agar di succo di frutta contenente circa 0,5 g di lievito. Posiziona ogni larva in modo che la sua estremità anteriore sia sulla pasta di lievito, per continuare a nutrirsi nonostante la motilità sconvolta. NOTA: per assicurarsi che i nervi segmentali larvali siano stati feriti, si può osservare la motilità del larvale interrotta dopo il trasferimento sulla piastra agar. Le larve danneggiate sono effettivamente paralizzate posteriormente al sito di lesioni, ma possono ancora muovere i loro ganci e l&#39;alimentazione. Un tasso di mortalità elevato di animali dopo il danno è comune quindi è meglio infettare 20-50% di animali in più di quanto sia necessario per un esperimento. </li><li> Posizionare le piastre di agar contenenti pasta di lievito e 10 larve ferite nel fondo di un piatto vuoto di 100 x 15 mm Petri. Coprire questa piastra di Petri, che ora contiene le larve ferite su una piastra agar con un tovagliolo di carta umido, assicurando che il tovagliolo non tocchi le larve o le piastre agar. Mettere questoPetri in un contenitore più grande dell&#39;aria, a RT. </li><li> Recuperare le larve per la dissezione dopo periodi specifici (6, 12 o 24 ore) dopo lesioni. NOTA: per esaminare gli effetti immediati di lesioni sul citochistone assonale, le larve possono essere disseccate direttamente dopo lesioni. Per esaminare i difetti di trasporto assonale, le larve possono essere disseccate circa 6 ore dopo il danno. Circa 12 h dopo l&#39;infortunio può essere osservato un accumulo di proteine ​​ubiquitinate, e 24 ore dopo l&#39;infortunio può essere osservata la degenerazione dei neuroni motori al NMJ. </li></ol> 5. Analisi della neurodegenerazione presso la NMJ <ol><li> Disseccare Drosophila larval NMJ come descritto in precedenza. 15 , 16 In breve, appoggiate le larve su un piatto di Sylgard, tagliate lungo la superficie dorsale e filettate con i perni in una goccia di tampone di dissezione per esporre la muscolatura della parete del corpo. Fissare le larve in 4% di paraformaldeide (PFA) o nella soluzione di Bouin in base all&#39;antiCorpi utilizzati per visualizzare i neuroni e muscoli. NOTA: la fissazione PFA deve essere utilizzata se i tag proteine ​​fluorescenti, come la Proteina Verde Fluorescente (GFP), devono essere visualizzati come il fissativo di Bouin può essere troppo duro. </li><li> Eseguire l&#39;immunofluorescenza, descritta in precedenza 11 , 13 , 16 , per segnare contemporaneamente i neuroni motori presinaptici e le pieghe muscolari postsinaptiche adiacenti (SSR). Visualizzare le membrane e gli assoni presinaptici con perossidasi di rafano coniugato fluorescently (HR: 1: 300) 17 e le zone attive possono essere macchiate utilizzando un anticorpo anti-Bruchpilot (Brp) (nc82; 1: 100; Developmental Studies Hybridoma Bank). Simultaneamente etichetta i muscoli post-sinaptici con un anticorpo anti-Dics Large (Dlg) (1: 10.000). 18 </li><li> Eseguire un dosaggio stabilito per quantificare la neurodegenerazione al NMJ come descritto in precedenza. 8 </suP&gt; , 9 , 10 , 11 , 12 , 13 , 14 In breve, visualizzare contemporaneamente singoli NMJ per entrambi i compartimenti pre e post-sinaptici. Tutti i marcatori etichettati con marcatori postsinaptici ma non marcatori presinaptici indicano siti di neurodegenerazione ( Figura 1 ). Il numero medio di bouton per NMJ e il numero medio di NMJ per animale possono essere quantificati. </li></ol>

<ol>
	<li>Bier, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophilia,+the+golden+bug,+emerges+as+a+tool+for+human+genetics.">Drosophilia, the golden bug, emerges as a tool for human genetics.</a> Nat. Rev. Genet. 6 (1), 9-23 (2005).</li><li>Ugur, B., Chen, K., Bellen, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+tools+and+assays+for+the+study+of+human+diseases.">Drosophila tools and assays for the study of human diseases.</a> Dis Model Mech. 9 (3), 235-244 (2016).</li><li>McGurk, L., Berson, A., Bonini, N. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+as+an+in+vivo+model+for+human+neurodegenerative+disease.">Drosophila as an in vivo model for human neurodegenerative disease.</a> Genetics. 201 (2), 377-402 (2015).</li><li>Shin, J. E., Cho, Y., Beirowski, B., Milbrandt, J., Cavalli, V., DiAntonio, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dual+leucine+zipper+kinase+is+required+for+retrograde+injury+signaling+and+axonal+regeneration.">Dual leucine zipper kinase is required for retrograde injury signaling and axonal regeneration.</a> Neuron. 74 (6), 1015-1022 (2012).</li><li>Xiong, X., Wang, X., Ewanek, R., Bhat, P., Diantonio, A., Collins, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protein+turnover+of+the+Wallenda/DLK+kinase+regulates+a+retrograde+response+to+axonal+injury.">Protein turnover of the Wallenda/DLK kinase regulates a retrograde response to axonal injury.</a> J Cell Biol. 191 (1), 211-223 (2010).</li><li>Xiong, X., Collins, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+conditioning+lesion+protects+axons+from+degeneration+via+the+Wallenda/DLK+MAP+kinase+signaling+cascade.">A conditioning lesion protects axons from degeneration via the Wallenda/DLK MAP kinase signaling cascade.</a> J Neurosci. 32 (2), 610-615 (2012).</li><li>Mishra, B., Ghannad-Rezaie, M., Li, J., Wang, X., Hao, Y., Ye, B., Chronis, N., Collins, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+microfluidics+chips+for+live+imaging+and+study+of+injury+responses+in+Drosophila+larvae.">Using microfluidics chips for live imaging and study of injury responses in Drosophila larvae.</a> J Vis Exp. (84), e50998 (2014).</li><li>Eaton, B. A., Fetter, R. D., Davis, G. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynactic+is+necessary+for+synapse+stabilization.">Dynactic is necessary for synapse stabilization.</a> Neuron. 34 (5), 729-741 (2002).</li><li>Eaton, B. A., Davis, G. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=LIM+Kinase1+controls+synaptic+stability+downstream+of+the+type+II+BMP+receptor.">LIM Kinase1 controls synaptic stability downstream of the type II BMP receptor.</a> Neuron. 47 (5), 695-708 (2005).</li><li>Pielage, J., Fetter, R. D., Davis, G. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Presynaptic+spectrin+is+essential+for+synapse+stabilization.">Presynaptic spectrin is essential for synapse stabilization.</a> Curr Biol. 15 (10), 918-928 (2005).</li><li>Pielage, J., Cheng, L., Fetter, R. D., Carlton, P. M., Sedat, J. W., Davis, G. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+presynaptic+giant+Ankyrin+stabilizes+the+NMJ+through+regulation+or+presynaptic+microtubules+and+transsynaptic+cell+adhesion.">A presynaptic giant Ankyrin stabilizes the NMJ through regulation or presynaptic microtubules and transsynaptic cell adhesion.</a> Neuron. 58 (2), 195-209 (2008).</li><li>Massaro, C. M., Pielage, J., Davis, G. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+mechanisms+that+enhance+synapse+stability+despite+persistent+disruption+of+the+spectrin/ankryin/microtubule+cytoskeleton.">Molecular mechanisms that enhance synapse stability despite persistent disruption of the spectrin/ankryin/microtubule cytoskeleton.</a> J Cell Biol. 187 (1), 101-117 (2009).</li><li>Lincoln, B. L., Alabsi, S. H., Frendo, N., Freund, R., Keller, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+neuronal+injury+follows+a+temporal+sequence+of+cellular+events+leading+to+degeneration+at+the+neuromuscular+junction.">Drosophila neuronal injury follows a temporal sequence of cellular events leading to degeneration at the neuromuscular junction.</a> J Exp Neurosci. 9, 1-9 (2015).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+apple+juice-agar+plates.">Drosophila apple juice-agar plates.</a> Cold Spring Harb Protoc. , (2011).</li><li>Brent, J. R., Werner, K. M., McCabe, B. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+larval+NMJ+immunohistochemistry.">Drosophila larval NMJ immunohistochemistry.</a> J Vis Exp. (25), (2009).</li><li>Smith, R., Taylor, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissection+and+imaging+of+active+zones+in+the+Drosophila+neuromuscular+junction.">Dissection and imaging of active zones in the Drosophila neuromuscular junction.</a> J Vis Exp. (50), (2011).</li><li>Jan, L., Jan, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antibodies+to+horseradish+peroxidase+as+specific+neuronal+markers+in+Drosophila+and+in+grasshopper+embryos.">Antibodies to horseradish peroxidase as specific neuronal markers in Drosophila and in grasshopper embryos.</a> Proc. Natl. Acad. Sci. 79 (8), 2700-2704 (1982).</li><li>Lahey, T., Gorczyca, M., Jia, X., Budnik, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Drosophila+tumor+suppressor+gene+dlg+is+required+for+normal+synaptic+bouton+structure.">The Drosophila tumor suppressor gene dlg is required for normal synaptic bouton structure.</a> Neuron. 13 (4), 823-835 (1994).</li></ol>

Gli autori non hanno nulla da rivelare.

La lesione meccanica neuronale descritta precedentemente e qui dimostrata può essere utilizzata per indurre lesioni / stress nei nervi segmentali delle larve Drosophila . 4 , 5 , 6 , 14 Questa tecnica sperimentale è stata impiegata in precedenza per disseccare la sequenza temporale degli eventi che conducono alla neurodegenerazione, nonché ad esaminare i cambiamenti trascrizionali ...

La degenerazione neuronale si verifica durante il normale sviluppo e può essere causata dal processo naturale di invecchiamento, lesioni, stress, o stati di malattia. Drosophila melanogaster , la mosca comune di frutta, fornisce un organismo modello semplice e potente per studiare la neurodegenerazione a causa delle notevoli somiglianze nei meccanismi molecolari che guidano la degenerazione dei neuroni. Queste somiglianze sono evidenziate dal fatto che circa il 70% dei geni umani associati alla malattia presenta un omologo Drosophila . 1 Inoltre, numerosi saggi e strumenti tecnologici per lo studio delle malattie neurodegenerative umane sono stati sviluppati e utilizzati in Drosophila. 2 , 3 All&#39;interno di Drosophila , la giunzione neuromuscolare (NMJ) permette di analizzare sia le proprietà cellulari che elettrofisiologiche e si è dimostrato un importante sistema per studiare la malattia neuromuscolare a causa del n visibileConnessioni euron-muscolari. 2 In questo studio, descriviamo un dosaggio in vivo di lesioni neuronali nelle larve Drosophila che consente la lesione riproducibile dei nervi segmentali. Questo infortunio motoneuron provoca una sequenza temporale di eventi cellulari che hanno determinato la neurodegenerazione al NMJ 24 h dopo lesioni. La capacità di lesioni riproducibili che provocano neurodegenerazione ha diverse applicazioni quali identificazione di geni specifici necessari per il processo degenerativo, dissezione delle risposte trascrizionali alla lesione neuronale e analisi delle cascate di segnalazione protettive. 4 , 5 , 6 Questo metodo è stato utilizzato anche in combinazione con microfluidici per studiare la degenerazione e la rigenerazione neuronali in animali vivi. 7 Utilizziamo un dosaggio quantitativo stabilito per esaminare il degenerato dei neuroni motoriIon a Drosophila NMJ dopo lesioni meccaniche. Questo saggio è basato sul fatto che la perdita di membrana e proteine ​​presinaptiche precede lo smontaggio del reticolo subsintattico (SSR) caratterizzato dalle pieghe della membrana muscolare postsinaptica. 8 , 9 , 10 , 11 , 12 , 13 Questo test consente la quantificazione di &quot;orme sinaptiche&quot; in cui il neurone pre-sinaptico ha perso la connessione con il muscolo postinaptico adiacente. Il processo degenerativo è stato dimostrato progressivo durante lo sviluppo della larve 12 e non può essere considerato per lo sviluppo alterato della sinapsia o la germinazione. 8 , 9 , 10 , 11 , 12 L&#39;annuncioIl vantaggio di utilizzare lesioni meccaniche sulle mutazioni preesistenti è che permette la dissezione della sequenza temporale di eventi cellulari che conducono alla neurodegenerazione presso la NMJ. 13

<table>
	<tbody>
		<tr>
			<td>Micro-dissecting scissors</td>
			<td>Fine Science Tools</td>
			<td>15000-08</td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont #3 Forceps</td>
			<td>Fine Science Tools</td>
			<td>11231-30</td>
			<td>Some people prefer size 3, while others prefer size 5</td>
		</tr>
		<tr>
			<td>Dumont #5 Forceps</td>
			<td>Fine Science Tools</td>
			<td>11251-30</td>
			<td>Some people prefer size 3, while others prefer size 5</td>
		</tr>
		<tr>
			<td>CO2 Air Tank</td>
			<td>Tech Air</td>
			<td>UN 1013</td>
			<td>Various tank sizes can be purchased/</td>
		</tr>
		<tr>
			<td>CO2 Anesthetizing Apparatus</td>
			<td>Genesee Scientific</td>
			<td>59-114</td>
			<td></td>
		</tr>
		<tr>
			<td>Stainless-steel pins, size 0.1</td>
			<td>Fine Science Tools</td>
			<td>26002-10</td>
			<td></td>
		</tr>
		<tr>
			<td>SylGard 184 Silicone Elastomer, Base and Curing Agent</td>
			<td>Dow Corning</td>
			<td>3097358-1004</td>
			<td>To pour dissecting plates</td>
		</tr>
		<tr>
			<td>Bouin&#39;s Solution</td>
			<td>Sigma</td>
			<td>HT 10132-1L</td>
			<td>Antibodies should be tested for their efficiency in Bouin&#39;s and PFA</td>
		</tr>
		<tr>
			<td>4% Paraformaldehyde in PBS</td>
			<td>Affymetrix</td>
			<td>FLY-8030-20</td>
			<td>Antibodies should be tested for their efficiency in Bouin&#39;s and PFA</td>
		</tr>
		<tr>
			<td>Dissecting Stereo MIcroscope</td>
			<td>AmScope</td>
			<td>SM-1BZ</td>
			<td></td>
		</tr>
		<tr>
			<td>Light Source</td>
			<td>AmScope</td>
			<td>HL150-AY-220V</td>
			<td></td>
		</tr>
		<tr>
			<td>anti- nc82 antibody</td>
			<td>Developmental Studies Hybridoma Bank</td>
			<td>nc82-s</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-discs large antibody</td>
			<td>Developmental Studies Hybridoma Bank</td>
			<td>AF3</td>
			<td></td>
		</tr>
		<tr>
			<td>Alexa Fluor anti-horseradish peroxidase</td>
			<td>Jackson Immunoresearch</td>
			<td>123-545-021; 123-585-021; 123-605-021</td>
			<td>One can you Alexa Fluor&#174; 488, 594 or 647</td>
		</tr>
		<tr>
			<td>Flystuff Grape Juice Agar Premix</td>
			<td>Genesee Scientific</td>
			<td>47-102</td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope slides</td>
			<td>Genesee Scientific</td>
			<td>29-101</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass Coverslips</td>
			<td>Fisher Scientific</td>
			<td>12-545-87</td>
			<td></td>
		</tr>
		<tr>
			<td>Thermo Scientific Nalgene Utility Box</td>
			<td>Fisher Scientific</td>
			<td>03-484C</td>
			<td>Used to create humid chamber for larval recovery</td>
		</tr>
	</tbody>
</table>

a simple neuronal mechanical injury methodology to study drosophila motor neuron degeneration

La degenerazione dei neuroni avviene durante il normale sviluppo e in risposta a lesioni, stress e malattie. I segni cellulari della degenerazione neuronale sono notevolmente simili negli esseri umani e negli invertebrati, così come i meccanismi molecolari che guidano questi processi. La mosca di frutta, Drosophila melanogaster , fornisce un organismo di modello genetico potente ma semplice per studiare le complessità cellulari delle malattie neurodegenerative. Infatti, circa il 70% dei geni umani associati alla malattia ha un omologo Drosophila e una pletora di strumenti e dosaggi sono stati descritti usando le mosche per studiare le malattie neurodegenerative umane. Più in particolare la giunzione neuromuscolare (NMJ) di Drosophila si è rivelata un efficace sistema per studiare le malattie neuromuscolari a causa della capacità di analizzare le connessioni strutturali tra il neurone e il muscolo. Qui, riportiamo un test in vivo di lesioni neuronali del motore in Drosophila , cheRiproducibilmente induce la neurodegenerazione a NMJ per 24 h. Utilizzando questa metodologia, abbiamo descritto una sequenza temporale di eventi cellulari che determinano la degenerazione dei motori neuronali. Il metodo del pregiudizio ha diverse applicazioni ed è stato utilizzato anche per identificare geni specifici necessari per la neurodegenerazione e per disseccare le risposte transcrizionali alla lesione neuronale.

Utilizzando la procedura qui presentata, abbiamo dimostrato che lesioni neuronali meccaniche consentono la dissezione temporale di eventi neurodegenerativi. 14 , 18 La sequenza degli eventi è stata precedentemente caratterizzata e inizia con un&#39;interruzione immediata del citoscheletro, seguita da difetti di traffico dell&#39;assone, un accumulo di proteine ​​ubiquitinate e una successiva neurodegenerazione 24 h post-lesi...

Watch this Scientific Journal Video about A Simple Neuronal Mechanical Injury Methodology to Study Drosophila Motor Neuron Degeneration at JoVE.com

A Simple Neuronal Mechanical Injury Methodology to Study Drosophila Motor Neuron Degeneration

Qui descriviamo un metodo semplice e ampiamente accessibile per danneggiare i nervi segmentali nelle larve Drosophila per visualizzare e quantificare la neurodegenerazione dei neuroni motori alla giunzione neuromuscolare (NMJ) delle larve di terzo istar.

Una semplice metodologia di lesioni meccaniche neuronali da studiare<em&gt; Drosophila</em&gt; Degenerazione dei motori neuronali

The degeneration of neurons occurs during normal development and in response to injury, stress, and disease. The cellular hallmarks of neuronal ...

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A Simple Neuronal Mechanical Injury Methodology to Study Drosophila Motor Neuron Degeneration

5.5K Views.  Quinnipiac University.  Qui descriviamo un metodo semplice e ampiamente accessibile per danneggiare i nervi segmentali nelle larve Drosophila per visualizzare e quantificare la neurodegenerazione dei neuroni motori alla giunzione neuromuscolare (NMJ) delle larve di terzo istar. 

Video: A Simple Neuronal Mechanical Injury Methodology to Study Drosophila Motor Neuron Degeneration

Laser Capture Microdissection of Drosophila Peripheral Neurons

The dendritic arborization (da) neurons of the Drosophila peripheral nervous system (PNS) provide an excellent model system in which to investigate the molecular mechanisms underlying class-specific dendrite morphogenesis1,2. To facilitate molecular analyses of class-specific da neuron development, it is vital to obtain these cells in a pure population. Although a range of different cell, and tissue-specific RNA isolation techniques exist for Drosophila cells, including magnetic bead based cell purification3,4, Fluorescent Activated Cell Sorting (FACS)5-8, and RNA binding protein based strategies9, none of these methods can be readily utilized for isolating single or multiple class-specific Drosophila da neurons with a high degree of spatial precision. Laser Capture Microdissection (LCM) has emerged as an extremely powerful tool that can be used to isolate specific cell types from tissue sections with a high degree of spatial resolution and accuracy. RNA obtained from isolated cells can then be used for analyses including qRT-PCR and microarray expression profiling within a given cell type10-16. To date, LCM has not been widely applied in the analysis of Drosophila tissues and cells17,18, including da neurons at the third instar larval stage of development. 
Here we present our optimized protocol for isolation of Drosophila da neurons using the infrared (IR) class of LCM. This method allows for the capture of single, class-specific or multiple da neurons with high specificity and spatial resolution. Age-matched third instar larvae expressing a UAS-mCD8::GFP19 transgene under the control of either the class IV da neuron specific ppk-GAL420 driver or the pan-da neuron specific 21-7-GAL421 driver were used for these experiments. RNA obtained from the isolated da neurons is of very high quality and can be directly used for downstream applications, including qRT-PCR or microarray analyses. Furthermore, this LCM protocol can be readily adapted to capture other Drosophila cell types a various stages of development dependent upon the cell type specific, GAL4-driven expression pattern of GFP.

Laser Capture Microdissection of Drosophila Peripheral Neurons

In this video-article we present a method for isolating single or multiple Drosophila da neurons from third instar larvae using the infrared capture (IR) class of Laser Capture Microdissection (LCM). RNA obtained from the isolated neurons can be readily used for downstream applications including qRT-PCR or microarray analyses.

Laser Microdissezione Cattura di Drosophila Neuroni periferici

The dendritic arborization (da) neurons of the Drosophila peripheral nervous system (PNS) provide an excellent model system in which to investigate the ...

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Neuroscienze

An Ex Vivo Laser-induced Spinal Cord Injury Model to Assess Mechanisms of Axonal Degeneration in Real-time

Injured CNS axons fail to regenerate and often retract away from the injury site. Axons spared from the initial injury may later undergo secondary axonal degeneration. Lack of growth cone formation, regeneration, and loss of additional myelinated axonal projections within the spinal cord greatly limits neurological recovery following injury. To assess how central myelinated axons of the spinal cord respond to injury, we developed an ex vivo living spinal cord model utilizing transgenic mice that express yellow fluorescent protein in axons and a focal and highly reproducible laser-induced spinal cord injury to document the fate of axons and myelin (lipophilic fluorescent dye Nile Red) over time using two-photon excitation time-lapse microscopy. Dynamic processes such as acute axonal injury, axonal retraction, and myelin degeneration are best studied in real-time. However, the non-focal nature of contusion-based injuries and movement artifacts encountered during in vivo spinal cord imaging make differentiating primary and secondary axonal injury responses using high resolution microscopy challenging. The ex vivo spinal cord model described here mimics several aspects of clinically relevant contusion/compression-induced axonal pathologies including axonal swelling, spheroid formation, axonal transection, and peri-axonal swelling providing a useful model to study these dynamic processes in real-time. Major advantages of this model are excellent spatiotemporal resolution that allows differentiation between the primary insult that directly injures axons and secondary injury mechanisms; controlled infusion of reagents directly to the perfusate bathing the cord; precise alterations of the environmental milieu (e.g., calcium, sodium ions, known contributors to axonal injury, but near impossible to manipulate in vivo); and murine models also offer an advantage as they provide an opportunity to visualize and manipulate genetically identified cell populations and subcellular structures. Here, we describe how to isolate and image the living spinal cord from mice to capture dynamics of acute axonal injury.

An Ex Vivo Laser-induced Spinal Cord Injury Model to Assess Mechanisms of Axonal Degeneration in Real-time

We present a protocol utilizing two-photon excitation time-lapse microscopy to simultaneously visualize the dynamics of axon and myelin injuries in real time. This proposed protocol permits studies of both intrinsic and extrinsic factors which can influence central myelinated axon fate after injury and contribute to permanent clinical disability.

Un<em&gt; Ex Vivo</em&gt; Laser-indotta Spinal Cord Injury modello per valutare i meccanismi di degenerazione assonale in tempo reale

Injured CNS axons fail to regenerate and often retract away from the injury site. Axons spared from the initial injury may later undergo secondary axonal ...

The Neuromuscular Junction: Measuring Synapse Size, Fragmentation and Changes in Synaptic Protein Density Using Confocal Fluorescence Microscopy

The neuromuscular junction (NMJ) is the large, cholinergic relay synapse through which mammalian motor neurons control voluntary muscle contraction. Structural changes at the NMJ can result in neurotransmission failure, resulting in weakness, atrophy and even death of the muscle fiber. Many studies have investigated how genetic modifications or disease can alter the structure of the mouse NMJ. Unfortunately, it can be difficult to directly compare findings from these studies because they often employed different parameters and analytical methods. Three protocols are described here. The first uses maximum intensity projection confocal images to measure the area of acetylcholine receptor (AChR)-rich postsynaptic membrane domains at the endplate and the area of synaptic vesicle staining in the overlying presynaptic nerve terminal. The second protocol compares the relative intensities of immunostaining for synaptic proteins in the postsynaptic membrane. The third protocol uses Fluorescence Resonance Energy Transfer (FRET) to detect changes in the packing of postsynaptic AChRs at the endplate. The protocols have been developed and refined over a series of studies. Factors that influence the quality and consistency of results are discussed and normative data are provided for NMJs in healthy young adult mice.

The neuromuscular junction (NMJ) is altered in a variety of conditions that can sometimes culminate in synaptic failure. This report describes fluorescence microscope-based methods to quantify such structural changes.

La giunzione neuromuscolare: Synapse Misurazione circonferenza, la frammentazione e Variazioni Synaptic Proteine ​​Densità Uso confocale microscopia a fluorescenza

The neuromuscular junction (NMJ) is the large, cholinergic relay synapse through which mammalian motor neurons control voluntary muscle contraction. ...

A Method to Inflict Closed Head Traumatic Brain Injury in Drosophila

Traumatic brain injury (TBI) affects millions of people each year, causing impairment of physical, cognitive, and behavioral functions and death. Studies using Drosophila have contributed important breakthroughs in understanding neurological processes. Thus, with the goal of understanding the cellular and molecular basis of TBI pathologies in humans, we developed the High Impact Trauma (HIT) device to inflict closed head TBI in flies. Flies subjected to the HIT device display phenotypes consistent with human TBI such as temporary incapacitation and progressive neurodegeneration. The HIT device uses a spring-based mechanism to propel flies against the wall of a vial, causing mechanical damage to the fly brain. The device is inexpensive and easy to construct, its operation is simple and rapid, and it produces reproducible results. Consequently, the HIT device can be combined with existing experimental tools and techniques for flies to address fundamental questions about TBI that can lead to the development of diagnostics and treatments for TBI. In particular, the HIT device can be used to perform large-scale genetic screens to understand the genetic basis of TBI pathologies.

A Method to Inflict Closed Head Traumatic Brain Injury in Drosophila

Here we describe a method to inflict closed head traumatic brain injury (TBI) in Drosophila. This method provides a gateway to investigate the cellular and molecular mechanisms that underlie TBI pathologies using the vast array of experimental tools and techniques available for flies.

Un metodo per infliggere Chiuso Testa trauma cranico in<em&gt; Drosophila</em

Traumatic brain injury (TBI) affects millions of people each year, causing impairment of physical, cognitive, and behavioral functions and death. Studies ...

Why Quantification Matters: Characterization of Phenotypes at the Drosophila Larval Neuromuscular Junction

Most studies on morphogenesis rely on qualitative descriptions of how anatomical traits are affected by the disruption of specific genes and genetic pathways. Quantitative descriptions are rarely performed, although genetic manipulations produce a range of phenotypic effects and variations are observed even among individuals within control groups.&#160;Emerging evidence shows that morphology, size and location of organelles play a previously underappreciated, yet fundamental role in cell function and survival. Here we provide step-by-step instructions for performing quantitative analyses of phenotypes at the Drosophila larval neuromuscular junction (NMJ). We use several reliable immuno-histochemical markers combined with bio-imaging techniques and morphometric analyses to examine the effects of genetic mutations on specific cellular processes. In particular, we focus on the quantitative analysis of phenotypes affecting morphology, size and position of nuclei within the striated muscles of Drosophila larvae. The Drosophila larval NMJ is a valuable experimental model to investigate the molecular mechanisms underlying the structure and the function of the neuromuscular system, both in health and disease. However, the methodologies we describe here can be extended to other systems as well.

Why Quantification Matters: Characterization of Phenotypes at the Drosophila Larval Neuromuscular Junction

Morphology, size and location of intracellular organelles are evolutionarily conserved and appear to directly affect their function. Understanding the molecular mechanisms underlying these processes has become an important goal of modern biology. Here we show how these studies can be facilitated by the application of quantitative techniques.

Perché Quantificazione Matters: Caratterizzazione dei fenotipi al<em&gt; Drosophila</em&gt; Larvale Giunzione neuromuscolare

Most studies on morphogenesis rely on qualitative descriptions of how anatomical traits are affected by the disruption of specific genes and genetic ...

A Simple Way to Measure Alterations in Reward-seeking Behavior Using Drosophila melanogaster

We describe a protocol for measuring ethanol self-administration in fruit flies (Drosophila melanogaster) as a proxy for changes in reward states. We demonstrate a simple way to tap into the fly reward system, modify experiences related to natural reward, and use voluntary ethanol consumption as a measure for changes in reward states. The approach serves as a relevant tool to study the neurons and genes that play a role in experience-mediated changes of internal state. The protocol is composed of two discrete parts: exposing the flies to rewarding and nonrewarding experiences, and assaying voluntary ethanol consumption as a measure of the motivation to obtain a drug reward. The two parts can be used independently to induce the modulation of experience as an initial step for further downstream assays or as an independent two-choice feeding assay, respectively. The protocol does not require a complicated setup and can therefore be applied in any laboratory with basic fly culture tools.

A Simple Way to Measure Alterations in Reward-seeking Behavior Using Drosophila melanogaster

We describe a protocol for inducing rewarding and nonrewarding experiences in fruit flies (Drosophila melanogaster) using voluntary ethanol consumption as a measure for changes in reward states.

Un modo semplice per misurare alterazioni in ricompensa il comportamento di ricerca Utilizzando<em&gt; Drosophila melanogaster</em

We describe a protocol for measuring ethanol self-administration in fruit flies (Drosophila melanogaster) as a proxy for changes in reward states. We ...

Modeling Neuronal Death and Degeneration in Mouse Primary Cerebellar Granule Neurons

Cerebellar granule neurons (CGNs) are a commonly used neuronal model, forming an abundant homogeneous population in the cerebellum. In light of their post-natal development, abundance, and accessibility, CGNs are an ideal model to study neuronal processes, including neuronal development, neuronal migration, and physiological neuronal activity stimulation. In addition, CGN cultures provide an excellent model for studying different modes of cell death including excitotoxicity and apoptosis. Within a week in culture, CGNs express N-methyl-D-aspartate (NMDA) receptors, a specific ionotropic glutamate receptor with many critical functions in neuronal health and disease. The addition of low concentrations of NMDA in conjunction with membrane depolarization to rodent primary CGN cultures has been used to model physiological neuronal activity stimulation while the addition of high concentrations of NMDA can be employed to model excitotoxic neuronal injury. Here, a method of isolation and culturing of CGNs from 6 day old pups as well as genetic manipulation of CGNs by adenoviruses and lentiviruses are described. We also present optimized protocols on how to stimulate NMDA-induced excitotoxicity, low-potassium-induced apoptosis, oxidative stress and DNA damage following transduction of these neurons.

This protocol describes a simple method for isolating and culturing primary mouse cerebral granule neurons (CGNs) from 6-7 day old pups, efficient transduction of CGNs for loss and gain of function studies, and modelling NMDA-induced neuronal excitotoxicity, low-potassium-induced cell death, DNA-damage, and oxidative stress using the same culture model.

Modellazione di morte neuronale e degenerazione in neuroni cerebellari del granello primario del Mouse

Cerebellar granule neurons (CGNs) are a commonly used neuronal model, forming an abundant homogeneous population in the cerebellum. In light of their ...

In Vivo Electrophysiological Measurement of Compound Muscle Action Potential from the Forelimbs in Mouse Models of Motor Neuron Degeneration

Assessing the functionality of the nerve axon provides detailed information on the progression of neuromuscular disorders. Electrophysiological recordings provide a sensitive approach to measure nerve conduction in humans and rodent models. To broaden the technical possibilities for electromyography in mice, the measurement of compound muscle action potentials (CMAPs) from the brachial plexus nerve in the forelimb using needle electrodes is described here. CMAP recordings after stimulating the sciatic nerve in hindlimbs have been previously described. The newly introduced method here allows for the evaluation of the nerve conductivity at an additional site, and thus provides a more profound overview of the neuromuscular functionality. The technique provides information on both the relative number of functional axons and the myelination level. Thereby, this method can be applied to assess both axonal diseases as well as demyelinating conditions. This minimally invasive method does not require extraction of the nerve and therefore it is suitable for repeated measurements for longitudinal follow-up in the same animal. Similar recordings are performed in clinical setups to emphasize the translational relevance of the method.

In Vivo Electrophysiological Measurement of Compound Muscle Action Potential from the Forelimbs in Mouse Models of Motor Neuron Degeneration

The measurement of nerve conduction is a useful tool to assess mouse models of neurodegeneration but it is frequently only applied to stimulate the sciatic nerve in hindlimbs. Here, we describe a technique to measure compound muscle action potential (CMAP) in vivo in the mouse forelimb muscles innervated by the brachial plexus.

In Vivo Elettrofisiologici misurazione del potenziale di azione muscolare composto da arti anteriori in modelli murini di degenerazione del motoneurone

Assessing the functionality of the nerve axon provides detailed information on the progression of neuromuscular disorders. Electrophysiological recordings ...

3D Kinematic Analysis for the Functional Evaluation in the Rat Model of Sciatic Nerve Crush Injury

Compared to the Sciatic Functional Index (SFI), kinematic analysis is a more reliable and sensitive method for performing functional evaluations of sciatic nerve injury rodent models. In this protocol, we describe a novel kinematic analysis method that uses a three-dimensional (3D) motion capture apparatus for functional evaluations using a rat sciatic nerve crush injury model. First, the rat is familiarized with treadmill walking. Markers are then attached to the designated bone landmarks and the rat is made to walk on the treadmill at the desired speed. Meanwhile, the posterior limb movements of the rat are recorded using four cameras. Depending on the software used, marker tracings are created using both automatic and manual modes and the desired data are produced after subtle adjustments. This method of kinematic analysis, which uses a 3D motion capture apparatus, offers numerous advantages, including superior precision and accuracy. Many more parameters can be investigated during the comprehensive functional evaluations. This method has several shortcomings that require consideration: The system is expensive, can be complicated to operate, and may produce data deviations due to skin shifting. Nevertheless, kinematic analysis using a 3D motion capture apparatus is useful for performing functional anterior and posterior limb evaluations. In the future, this method may become increasingly useful for generating accurate assessments of various traumas and diseases.

We introduce a kinematic analysis method that uses a three-dimensional motion capture apparatus containing four cameras and data processing software for performing functional evaluations during fundamental research involving rodent models.

Analisi kinematica 3D per la valutazione funzionale nel modello di ratto di lesioni da schiacciamento del nervo sciatico

Compared to the Sciatic Functional Index (SFI), kinematic analysis is a more reliable and sensitive method for performing functional evaluations of ...

Visualizing Synaptic Degeneration in Adult Drosophila in Association with Neurodegeneration

Drosophila serves as a useful model for assessing synaptic structure and function associated with neurodegenerative diseases. While much work has focused on neuromuscular junctions (NMJs) in Drosophila larvae, assessing synaptic integrity in adult Drosophila has received much less attention. Here we provide a straightforward method for dissection of the dorsal longitudinal muscles (DLMs), which are required for flight ability. In addition to flight as a behavioral readout, this dissection allows for the both DLM synapses and muscle tissue to be amenable to structural analysis using fluorescently labeled antibodies for synaptic markers or proteins of interest. This protocol allows for the evaluation of the structural integrity of synapses in adult Drosophila during aging to model the progressive, age-dependent nature of most neurodegenerative diseases.

Visualizing Synaptic Degeneration in Adult Drosophila in Association with Neurodegeneration

The goal of this procedure is to dissect the dorsal longitudinal muscle (DLM) tissue to assess the structural integrity of DLM neuromuscular junctions (NMJs) in neurodegenerative disease models using Drosophila melanogaster.

Visualizzazione della degenerazione sinaptica nella Drosophila adulta in associazione con la neurodegenerazione

Drosophila serves as a useful model for assessing synaptic structure and function associated with neurodegenerative diseases. While much work has focused ...

Una semplice metodologia di lesioni meccaniche neuronali da studiare

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Laser Microdissezione Cattura di Drosophila Neuroni periferici

Un

La giunzione neuromuscolare: Synapse Misurazione circonferenza, la frammentazione e Variazioni Synaptic Proteine Densità Uso confocale microscopia a fluorescenza

Un metodo per infliggere Chiuso Testa trauma cranico in

Perché Quantificazione Matters: Caratterizzazione dei fenotipi al

Un modo semplice per misurare alterazioni in ricompensa il comportamento di ricerca Utilizzando

Modellazione di morte neuronale e degenerazione in neuroni cerebellari del granello primario del Mouse

In Vivo Elettrofisiologici misurazione del potenziale di azione muscolare composto da arti anteriori in modelli murini di degenerazione del motoneurone

Analisi kinematica 3D per la valutazione funzionale nel modello di ratto di lesioni da schiacciamento del nervo sciatico

Visualizzazione della degenerazione sinaptica nella Drosophila adulta in associazione con la neurodegenerazione

Una semplice metodologia di lesioni meccaniche neuronali da studiare

Riepilogo

Esplora Altri Video

Capitoli in questo video

Laser Microdissezione Cattura di Drosophila Neuroni periferici

Un

La giunzione neuromuscolare: Synapse Misurazione circonferenza, la frammentazione e Variazioni Synaptic Proteine ​​Densità Uso confocale microscopia a fluorescenza

Un metodo per infliggere Chiuso Testa trauma cranico in

Perché Quantificazione Matters: Caratterizzazione dei fenotipi al

Un modo semplice per misurare alterazioni in ricompensa il comportamento di ricerca Utilizzando

Modellazione di morte neuronale e degenerazione in neuroni cerebellari del granello primario del Mouse

In Vivo Elettrofisiologici misurazione del potenziale di azione muscolare composto da arti anteriori in modelli murini di degenerazione del motoneurone

Analisi kinematica 3D per la valutazione funzionale nel modello di ratto di lesioni da schiacciamento del nervo sciatico

Visualizzazione della degenerazione sinaptica nella Drosophila adulta in associazione con la neurodegenerazione

La giunzione neuromuscolare: Synapse Misurazione circonferenza, la frammentazione e Variazioni Synaptic Proteine Densità Uso confocale microscopia a fluorescenza