Name: modeling charcot-marie-tooth disease in vitro by transfecting mouse primary motoneurons
Uploaded: 2019-01-07T14:00:00
Description: Watch this Scientific Journal Video about Modeling Charcot-Marie-Tooth Disease In Vitro by Transfecting Mouse Primary Motoneurons at JoVE.com

We would like to thank the &#34;Association pour le d&#233;veloppement de la neurog&#233;n&#233;tique&#34; for Dr. Jacquier&#39;s fellowship and AFM-Telethon for its support through MyoNeurAlp strategic plan. We would also like to thank Dr. Chris Henderson, Dr. William Camu, Dr. Brigitte Pettmann, Dr. Cedric Raoul, and Dr. Georg Haase, who participated in developing and improving the technique and spread their knowledge.

All procedures involving animals were accepted by the ethical committee of the institution.
1. Solution Preparation
<ol>
	<li>Prepare 10 mL of 4% BSA dialyzed in L-15 medium.
	<ol>
		<li>Dissolve bovine serum albumin powder at 4% (w/v) in 10 mL of L-15 medium.</li>
		<li>Add the solution to a 20 mL dialysis cassette with a 20 kDa cut-off. Dialyze against 500 mL of L-15 medium for 3 days under agitation at 4 &#176;C. Change the L-15 medium every day.</li>
		<li>Filter the solution through a 0...

<ol>
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J., 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=Inclusion+body+myopathy+associated+with+Paget+disease+of+bone+and+frontotemporal+dementia+is+caused+by+mutant+valosin-containing+protein.">Inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia is caused by mutant valosin-containing protein.</a> Nature Genetics. 36 (4), 377-381 (2004).</li><li>Brown, R. H., Al-Chalabi, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amyotrophic+Lateral+Sclerosis.">Amyotrophic Lateral Sclerosis.</a> New England Journal of Medicine. 377 (2), 162-172 (2017).</li><li>Taylor, J. P., Brown, R. H., Cleveland, D. 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E., 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=GDNF:+a+potent+survival+factor+for+motoneurons+present+in+peripheral+nerve+and+muscle.">GDNF: a potent survival factor for motoneurons present in peripheral nerve and muscle.</a> Science. 266 (5187), 1062-1064 (1994).</li><li>Schaller, S., 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=Novel+combinatorial+screening+identifies+neurotrophic+factors+for+selective+classes+of+motor+neurons.">Novel combinatorial screening identifies neurotrophic factors for selective classes of motor neurons.</a> Proceedings of the National Academy of Sciences. 114 (12), E2486-E2493 (2017).</li><li>Jacquier, A., 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=Alsin/Rac1+signaling+controls+survival+and+growth+of+spinal+motoneurons.">Alsin/Rac1 signaling controls survival and growth of spinal motoneurons.</a> Annals of Neurology. 60 (1), 105-117 (2006).</li><li>Raoul, C., 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=Chronic+activation+in+presymptomatic+amyotrophic+lateral+sclerosis+(ALS)+mice+of+a+feedback+loop+involving+Fas,+Daxx,+and+FasL.">Chronic activation in presymptomatic amyotrophic lateral sclerosis (ALS) mice of a feedback loop involving Fas, Daxx, and FasL.</a> Proceedings of the National Academy of Sciences. 103 (15), 6007-6012 (2006).</li><li>Madji Hounoum, B., 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=Wildtype+motoneurons,+ALS-Linked+SOD1+mutation+and+glutamate+profoundly+modify+astrocyte+metabolism+and+lactate+shuttling.">Wildtype motoneurons, ALS-Linked SOD1 mutation and glutamate profoundly modify astrocyte metabolism and lactate shuttling.</a> Glia. 65 (4), 592-605 (2017).</li><li>Magrane, J., Sahawneh, M. A., Przedborski, S., Estevez, A. G., Manfredi, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitochondrial+Dynamics+and+Bioenergetic+Dysfunction+Is+Associated+with+Synaptic+Alterations+in+Mutant+SOD1+Motor+Neurons.">Mitochondrial Dynamics and Bioenergetic Dysfunction Is Associated with Synaptic Alterations in Mutant SOD1 Motor Neurons.</a> Journal of Neuroscience. 32 (1), 229-242 (2012).</li><li>Jacquier, A., 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=Cryptic+amyloidogenic+elements+in+mutant+NEFH+causing+Charcot-Marie-Tooth+2+trigger+aggresome+formation+and+neuronal+death.">Cryptic amyloidogenic elements in mutant NEFH causing Charcot-Marie-Tooth 2 trigger aggresome formation and neuronal death.</a> Acta Neuropathologica Communications. 5, (2017).</li><li>Aebischer, J., 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=IFN&#947;+triggers+a+LIGHT-dependent+selective+death+of+motoneurons+contributing+to+the+non-cell-autonomous+effects+of+mutant+SOD1.">IFN&#947; triggers a LIGHT-dependent selective death of motoneurons contributing to the non-cell-autonomous effects of mutant SOD1.</a> Cell Death and Differentiation. 18 (5), 754-768 (2011).</li><li>Wiese, S., 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=Isolation+and+enrichment+of+embryonic+mouse+motoneurons+from+the+lumbar+spinal+cord+of+individual+mouse+embryos.">Isolation and enrichment of embryonic mouse motoneurons from the lumbar spinal cord of individual mouse embryos.</a> Nature Protocols. 5 (1), 31-38 (2010).</li><li>Camu, W., Henderson, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+of+embryonic+rat+motoneurons+by+panning+on+a+monoclonal+antibody+to+the+low-affinity+NGF+receptor.">Purification of embryonic rat motoneurons by panning on a monoclonal antibody to the low-affinity NGF receptor.</a> Journal of Neuroscience Methods. 44 (1), 59-70 (1992).</li><li>Conrad, R., Jablonka, S., Sczepan, T., Sendtner, M., Wiese, S., Klausmeyer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lectin-based+Isolation+and+Culture+of+Mouse+Embryonic+Motoneurons.">Lectin-based Isolation and Culture of Mouse Embryonic Motoneurons.</a> Journal of Visualized Experiments. (55), (2011).</li><li>Wichterle, H., Lieberam, I., Porter, J. A., 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=Directed+differentiation+of+embryonic+stem+cells+into+motor+neurons.">Directed differentiation of embryonic stem cells into motor neurons.</a> Cell. 110 (3), 385-397 (2002).</li><li>Francius, C., Clotman, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generating+spinal+motor+neuron+diversity:+a+long+quest+for+neuronal+identity.">Generating spinal motor neuron diversity: a long quest for neuronal identity.</a> Cellular and Molecular Life Sciences. 71 (5), 813-829 (2014).</li><li>Neto, E., 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=Compartmentalized+Microfluidic+Platforms:+The+Unrivaled+Breakthrough+of+In+Vitro+Tools+for+Neurobiological+Research.">Compartmentalized Microfluidic Platforms: The Unrivaled Breakthrough of In Vitro Tools for Neurobiological Research.</a> The Journal of Neuroscience. 36 (46), 11573-11584 (2016).</li><li>Matsuda, T., Cepko, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electroporation+and+RNA+interference+in+the+rodent+retina+in+vivo+and+in+vitro.">Electroporation and RNA interference in the rodent retina in vivo and in vitro.</a> Proceedings of the National Academy of Sciences of the United States of America. 101 (1), 16-22 (2004).</li><li>Sleigh, J. N., Weir, G. A., Schiavo, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple,+step-by-step+dissection+protocol+for+the+rapid+isolation+of+mouse+dorsal+root+ganglia.">A simple, step-by-step dissection protocol for the rapid isolation of mouse dorsal root ganglia.</a> BMC Research Notes. 9, (2016).</li><li>Yu, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+efficient+method+for+gene+delivery+into+mouse+dorsal+root+ganglia+neurons.">Highly efficient method for gene delivery into mouse dorsal root ganglia neurons.</a> Frontiers in Molecular Neuroscience. 8 (2), (2015).</li><li>Malin, S. A., Davis, B. M., Molliver, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+dissociated+sensory+neuron+cultures+and+considerations+for+their+use+in+studying+neuronal+function+and+plasticity.">Production of dissociated sensory neuron cultures and considerations for their use in studying neuronal function and plasticity.</a> Nature Protocols. 2 (1), 152-160 (2007).</li></ol>

One of the critical points in this protocol is that the mouse embryos are dissected at a precise time window during development (E12.5) to optimize the amount of MNs obtained at the end. In addition, for optimal yield, the dissection should be performed in the morning or early in the afternoon. Before E12.5 (e.g., at E11.5), dissection is difficult, especially regarding the elimination of the meninges. After E12.5, the number of obtained MNs drops significantly. To control the embryo stage of development, adult ...

Neuromuscular diseases encompass a variety of clinically and genetically distinct pathologies that are characterized by the alteration of muscle and/or the nervous system. Because of advances in sequencing technologies, hundreds of genes responsible for these rare disorders have been identified during the last decade (list available at the Neuromuscular Disease Center, http://neuromuscular.wustl.edu/index.html). The variety of identified mutations indicates that different mutations in a single gene can cause different phenotypes and diseases1,2,3 and that mutations in different genes can produce similar phenotypes4,5. In this context, there are efforts to develop cellular models that can become powerful tools for analyzing mutation consequences and pathological mechanisms.
Spinal MNs have large somas located in the ventral horns of the spinal cord, form long axons to target skeletal muscle fibers, and allow for voluntary movements through the release of acetylcholine at neuromuscular junctions. Since MNs are affected by neuromuscular diseases such as amyotrophic lateral sclerosis, Charcot-Marie-Tooth disease (CMT), and spinal muscular atrophy, Dr. Henderson and colleagues developed the first protocol6 that allowed for cultivation of in vitro spinal MNs and the discovery of neurotrophic factor GDNF7 (glial cell derived neurotrophic factor). Technical refinements since then have allowed for more accurate purification of spinal MNs and their subtypes using FACS8, but enrichment by density gradient remains powerful and widely used in laboratories currently working with primary spinal MNs9,10,11,12,13,14. Subsequently, it is also possible to obtain a higher MN purification grade through immunopanning by taking advantage of surface marker p75(NTR) 15,16,17.
The spinal cord contains different subtypes of cervical, thoracic, and lumbar MNs, as well as median and lateral motor columns that differ among their location in the anterior horn on a dorso-ventral axis and among the targets they innervate8,18. Primary MN cultures can recover all of these MN subtypes in physiological proportions. The main limitation of this technique is the low number of MNs obtained at the end of the procedure; in fact, it can be expected to obtain around 105 MNs from six embryos, which is suitable for microscopy but limiting for biochemistry experiments. To perform experiments with more standardized subtypes and abundant MNs (&#62;106 cells), embryonic stem cell-derived MNs should be considered18.
Transfection of wild-type/mutant transgenes or knockdown endogenous genes into primary MNs is a rapid and helpful tool for deciphering physiopathological pathways, especially when mouse models are unavailable. Magnetofection is one technique for transfecting primary neurons, similar to lipofection without the related neurotoxicity. Furthermore, transfection can be performed on mature neurons after several days in vitro, unlike techniques based on electroporation9. However, one disadvantage of this technique is that the beads bind nucleic acids in the culture, causing noise in DAPI labeling. Viral infection is likely the most efficient technique for transfecting MNs; however, magnetofection does not require certain safety procedures needed for viral production and cellular infection.

<table>
	<tbody>
		<tr>
			<td>Material</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Silicone dissection dish</td>
			<td>Living systems instrumentation</td>
			<td>DD-90-S-BLK-3PK</td>
			<td>Sylgard</td>
		</tr>
		<tr>
			<td>round coverslip</td>
			<td>NeuVitro, Knittel glass</td>
			<td>GG-12-Pre</td>
			<td>12 mm</td>
		</tr>
		<tr>
			<td>Slide a Lyzer cassettes</td>
			<td>ThermoFisher Scientific</td>
			<td>66030</td>
			<td>20,000 MWCO ; 30 mL</td>
		</tr>
		<tr>
			<td>Filter unit</td>
			<td>Millipore</td>
			<td>SCGVU02RE</td>
			<td></td>
		</tr>
		<tr>
			<td>GP Sterile Syringe Filters</td>
			<td>Millipore</td>
			<td>SLGP033RS</td>
			<td></td>
		</tr>
		<tr>
			<td>4 well plate</td>
			<td>ThermoFisher Scientific</td>
			<td>167063</td>
			<td>Nunclon Delta treated plate</td>
		</tr>
		<tr>
			<td>forceps</td>
			<td>FST by Dumont</td>
			<td>11252-20</td>
			<td>#5 forceps</td>
		</tr>
		<tr>
			<td>scissor</td>
			<td>FST by Dumont</td>
			<td>14060-10</td>
			<td>fine scissors</td>
		</tr>
		<tr>
			<td>scalpel</td>
			<td>FST by Dumont</td>
			<td>10035-20</td>
			<td>curved blade</td>
		</tr>
		<tr>
			<td>scalpel</td>
			<td>FST by Dumont</td>
			<td>10316-14</td>
			<td>micro-knife scalpel</td>
		</tr>
		<tr>
			<td>Petri dish</td>
			<td>Greiner</td>
			<td>663102</td>
			<td>&#248; x h = 100 x 15 mm</td>
		</tr>
		<tr>
			<td>15 mL polypropylene tube</td>
			<td>Falcon</td>
			<td>352096</td>
			<td></td>
		</tr>
		<tr>
			<td>filter paper</td>
			<td>Watman</td>
			<td>1001125</td>
			<td>circle, 125 mm diameter</td>
		</tr>
		<tr>
			<td>glass chamber slide</td>
			<td>Lab-Tek</td>
			<td>154526</td>
			<td>4 chambers</td>
		</tr>
		<tr>
			<td>Plasmid pCAGEN</td>
			<td>Addgene</td>
			<td>#11160</td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Solutions and mediums</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine serum albumin</td>
			<td>Sigma-Aldrich</td>
			<td>A9418</td>
			<td></td>
		</tr>
		<tr>
			<td>L-15 medium</td>
			<td>ThermoFisher Scientific</td>
			<td>11415056</td>
			<td></td>
		</tr>
		<tr>
			<td>L-15 medium, no red phenol</td>
			<td>ThermoFisher Scientific</td>
			<td>21083027</td>
			<td></td>
		</tr>
		<tr>
			<td>Insulin</td>
			<td>Sigma-Aldrich</td>
			<td>I6634</td>
			<td></td>
		</tr>
		<tr>
			<td>Putrescine</td>
			<td>Sigma-Aldrich</td>
			<td>P5780</td>
			<td></td>
		</tr>
		<tr>
			<td>Conalbumin</td>
			<td>Sigma-Aldrich</td>
			<td>C7786</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium selenite</td>
			<td>Sigma-Aldrich</td>
			<td>S5261</td>
			<td></td>
		</tr>
		<tr>
			<td>Progesterone</td>
			<td>Sigma-Aldrich</td>
			<td>P8783</td>
			<td></td>
		</tr>
		<tr>
			<td>Poly-DL-Ornithine</td>
			<td>Sigma-Aldrich</td>
			<td>P8638</td>
			<td></td>
		</tr>
		<tr>
			<td>Laminin</td>
			<td>Sigma-Aldrich</td>
			<td>L2020</td>
			<td></td>
		</tr>
		<tr>
			<td>trypsin 2.5%, 10x</td>
			<td>ThermoFisher Scientific</td>
			<td>15090046</td>
			<td></td>
		</tr>
		<tr>
			<td>DNAse</td>
			<td>Sigma-Aldrich</td>
			<td>DN25</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS w/o Ca Mg</td>
			<td>ThermoFisher Scientific</td>
			<td>14190144</td>
			<td>without Mg2+ Ca2+</td>
		</tr>
		<tr>
			<td>sodium bicarbonate</td>
			<td>ThermoFisher Scientific</td>
			<td>25080094</td>
			<td></td>
		</tr>
		<tr>
			<td>Neuron cell culture medium</td>
			<td>ThermoFisher Scientific</td>
			<td>A3582901</td>
			<td>Neurobasal Plus medium</td>
		</tr>
		<tr>
			<td>HBSS</td>
			<td>Sigma-Aldrich</td>
			<td>H6648-500ML</td>
			<td></td>
		</tr>
		<tr>
			<td>HEPES buffer 1 M</td>
			<td>ThermoFisher Scientific</td>
			<td>15630056</td>
			<td></td>
		</tr>
		<tr>
			<td>Density gradiant medium</td>
			<td>Sigma-Aldrich</td>
			<td>D1556</td>
			<td>Optiprep</td>
		</tr>
		<tr>
			<td>supplement medium</td>
			<td>ThermoFisher Scientific</td>
			<td>A3582801</td>
			<td>B-27 Plus</td>
		</tr>
		<tr>
			<td>Horse serum heat inactivated</td>
			<td>ThermoFisher Scientific</td>
			<td>26050-088</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Glutamine 200 mM</td>
			<td>ThermoFisher Scientific</td>
			<td>25030024</td>
			<td></td>
		</tr>
		<tr>
			<td>2-mercaptoethanol</td>
			<td>ThermoFisher Scientific</td>
			<td>31350010</td>
			<td></td>
		</tr>
		<tr>
			<td>penicilline/streptomycine</td>
			<td>ThermoFisher Scientific</td>
			<td>15140122</td>
			<td>10,000 U/ml</td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Immuno fluorescence</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>PBS, 10x</td>
			<td>ThermoFisher Scientific</td>
			<td>X0515</td>
			<td>without Mg2+ Ca2+</td>
		</tr>
		<tr>
			<td>Paraformaldehyde (PFA)</td>
			<td>Sigma-Aldrich</td>
			<td>441244</td>
			<td></td>
		</tr>
		<tr>
			<td>normal goat serum</td>
			<td>Sigma-Aldrich</td>
			<td>G6767</td>
			<td></td>
		</tr>
		<tr>
			<td>glycine</td>
			<td>Sigma-Aldrich</td>
			<td>G7126</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma-Aldrich</td>
			<td>T8787</td>
			<td></td>
		</tr>
		<tr>
			<td>Choline Acetyl Transferase (CHAT)</td>
			<td>Chemicon</td>
			<td>Ab144P</td>
			<td></td>
		</tr>
		<tr>
			<td>Neurofilament H non phosphorylated (SMI32)</td>
			<td>Biolegends</td>
			<td>SMI-32P</td>
			<td>IF at 1/1000</td>
		</tr>
		<tr>
			<td>Islet-1</td>
			<td>DSHB</td>
			<td>40.2D6</td>
			<td></td>
		</tr>
		<tr>
			<td>Islet-2</td>
			<td>DSHB</td>
			<td>39.4D5</td>
			<td></td>
		</tr>
		<tr>
			<td>Hb9</td>
			<td>DSHB</td>
			<td>81.5C10</td>
			<td></td>
		</tr>
		<tr>
			<td>Vectashield mounting medium</td>
			<td>Vector Lab</td>
			<td>H-1000</td>
			<td></td>
		</tr>
		<tr>
			<td>Beta3 tubulin (Tuj1 clone)</td>
			<td>Biolegends</td>
			<td>801201</td>
			<td>IF at 1/1000</td>
		</tr>
		<tr>
			<td>Lc3b</td>
			<td>Cell Signaling Technology</td>
			<td>#2775</td>
			<td>IF at 1/200</td>
		</tr>
	</tbody>
</table>

modeling charcot-marie-tooth disease in vitro by transfecting mouse primary motoneurons

Neurodegeneration of spinal motoneurons (MNs) is implicated in a large spectrum of neurological disorders including amyotrophic lateral sclerosis, Charcot-Marie-Tooth disease, and spinal muscular atrophy, which are all associated with muscular atrophy. Primary cultures of spinal MNs have been used widely to demonstrate the involvement of specific genes in such diseases and characterize the cellular consequences of their mutations. This protocol models a primary MN culture derived from the seminal work of Henderson and colleagues more than twenty years ago. First, we detail a method of dissecting the anterior horns of the spinal cord from a mouse embryo and isolating the MNs from neighboring cells using a density gradient. Then, we present a new way of efficiently transfecting MNs with expression plasmids using magnetofection. Finally, we illustrate how to fix and immunostain primary MNs. Using neurofilament mutations that cause Charcot-Marie-Tooth disease type 2, this protocol demonstrates a qualitative approach to expressing proteins of interest and studying their involvement in MN growth, maintenance, and survival.

After 24 hours in the culture, motoneurons (MNs) should already show significant axonal growth (at least 6 times longer than the soma size). In the following days, axons should continue to grow and display branching (Figure 2). There will be different morphologies due to subtype specificities. For example, median column MNs that innervate axial muscles have shorter and more branched axons than lateral motor column MNs that innervate limb muscles<sup class="xr...

Watch this Scientific Journal Video about Modeling Charcot-Marie-Tooth Disease In Vitro by Transfecting Mouse Primary Motoneurons at JoVE.com

Modeling Charcot-Marie-Tooth Disease In Vitro by Transfecting Mouse Primary Motoneurons

The goal of this technique is to prepare a highly enriched culture of primary motoneurons (MNs) from murine spinal cord. To evaluate the consequences of mutations causing MN diseases, we describe here the isolation of these isolated MNs and their transfection by magnetofection.

Modeling Charcot-Marie-Tooth Disease In Vitro by Transfecting Mouse Primary Motoneurons

Neurodegeneration of spinal motoneurons (MNs) is implicated in a large spectrum of neurological disorders including amyotrophic lateral sclerosis, ...

This method can help to address key questions in neurobiology, such as motor neuron polarity, axon guidance, axon trafficking, and neurodegenerative mechanisms. The main advantage of this technique is to obtain a highly enriched motor neuron culture while we take to express our knockdown protein by minute affection. To begin this procedure, place one embryo in a dish of dissection media coded with silicon.Under the microscope, hold the embryo with the abdomen against the silicon with forceps. With the second pair of forceps, insert one of the tips into the central canal of the rostrad spinal cord. Then, close the forceps to tear the dorsal tissue slightly.Repeat this operation towards the connell side until the entire spinal cord is opened. Next, position the embryo so that the open spinal cord is against the silicon. Subsequently, detach the rostrad part of the spinal cord from the body.Pinch the rostrad part of the spinal cord, and pull the embryo by the head to extract the spinal cord. Carefully pull away any remaining meninges and DRGs still attached to the spinal cord. Flatten the spinal cord on the silicon and using a scalpel, remove the dorsal half of the cord by cutting along the middle of each side.Cut the middle part into ten pieces, and transfer them to a new tube. To prepare spinal cords cell suspension, collect the spinal cord pieces at the bottom of the tube. Replace HBSS with one milliliter of Ham F-10 medium and add ten microliters of trypsin.Incubate the tube for ten minutes at 37 degrees Celsius. To stop the enzymatic digestion, transfer the fragments to a new 15 milliliter tube, containing 800 microliters of complete L-15 medium, 100 microliters of 4%BSA, and 100 microliters of DNAs and titrate, twice. Let the fragments settle for two minutes before collecting the supernatant in a fresh 15 milliliter tube.Gently add two milliliters of 4%BSA at the bottom of the supernatant tube. Centro fuse it at 470 x gravity for 5 minutes. After 5 minutes, remove the supernatant and re-suspend the cell pallet with 2 milliliters of complete L-15 medium.For motoneuron enrichment, split the cell suspension into two 15 milliliter tubes. Then, add two milliliters of L-15 PH medium to each tube. If starting with six embryos, use the equivalent of three embryos per tube, and three milliliters of medium.Slowly add 2 milliliters of density gradience solution, to the bottom of each tube to obtain a sharp interface. Next, centro fuse it at 830 x gravity for 15 minutes at room temperature. After this step, small cells should be at the bottom of the tube, whereas large cells-such as the motoneuron-should be at the density gradient solution/medium interface.Asperae 1 to 2 milliliters of the cells at the interface and transfer them to a fresh 15 milliliter tube. Adjust the volume to ten milliliters with L-15 PH medium. Subsequently, add two milliliters of the 4%BSA cushion to the bottom of the two tubes.And centro fuse at 470 x gravity for 5 minutes at room temperature. After 5 minutes, remove the supernatant and re-suspend the pallet and 3 milliliters of complete L-15 medium. Repeat the centrifugate at 470 x gravity for 5 minutes at room temperature.Then, remove the supernatant and re-suspend the cell pallet and two milliliters of complete culture medium. To culture motor neurons, dilute them to 5, 000-10, 000 cells in 500 microliters of culture medium per well in a 24 well plate. Then, remove the laminae solution with at P-1, 000 pipet tip.Immediately transfer the motor neurons diluted in culture medium. to the coding plates to avoid drying. To prepare DNA, re-suspend 1 microgram of DNA in 50 microliters of neuronal culture medium.And vortex for 5 seconds. To prepare the B tube, re-suspend 1.5 microliters of beads in 50 microliters of neuronal culture medium. Add 50 microliters of bead solution to 50 microliters of DNA solution and incubate for 20 minutes at room temperature.During this incubation, withdraw 100 microliters of culture medium from the well that will be transfected. Subsequently, transfer 100 microliters of the DNA bead mix to each well. And incubate the 24 well plate, 20-30 minutes on the magnetic plate at 37 degrees Celsius.Shown here, is the modem neuron morphology revealed by standing of endogenous non-phosphorylated neurofilament heavy chain after four days of culture. In these images, show the modem neuron morphology after four days in vitro and transfected for EGFP trans gene by magnetofection at day two. Motto neurons were counter-stained with the marker SMI-32 or the pan-neuro marker TUJ-1 and the arrows indicate the soma of the neurons.These are their confocal images of magneto fected motor neurons, expressing wild type or mutant EGFP NEFH constructs and stained for their autophagic marker LC-3B. Arrows show the mutant EGFP NEFH protein aggregates that are also LC-3B positive Following this procedure, montoholda curcha can be analyzed by video microscopy to visualize axon trafficking and add some guidance. After its initial development to address fundamental questions in neural biology, this technique also prove to be a powerful tool to explore physio pathological mechanisms implicating the spectrum of motoneuron disorders, such as toxic shock syndrome disease, samuel trophic lateral sclerosis, or spinal muscular atrophy.

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Research

JoVE Journal

Neuroscience

Transfection of Mouse Retinal Ganglion Cells by in vivo Electroporation

The targeting and refinement of RGC projections to the midbrain is a popular and powerful model system for studying how precise patterns of neural connectivity form during development. In mice, retinofugal projections are arranged in a topographic manner and form eye-specific layers in the Lateral Geniculate Nucleus (dLGN) of the thalamus and the Superior Colliculus (SC). The development of these precise patterns of retinofugal projections has typically been studied by labeling populations of RGCs with fluorescent dyes and tracers, such as horseradish peroxidase1-4. However, these methods are too coarse to provide insight into developmental changes in individual RGC axonal arbor morphology that are the basis of retinotopic map formation. They also do not allow for the genetic manipulation of RGCs.
Recently, electroporation has become an effective method for providing precise spatial and temporal control for delivery of charged molecules into the retina5-11. Current retinal electroporation protocols do not allow for genetic manipulation and tracing of retinofugal projections of a single or small cluster of RGCs in postnatal mice. It has been argued that postnatal in vivo electroporation is not a viable method for transfecting RGCs since the labeling efficiency is extremely low and hence requires targeting at embryonic ages when RGC progenitors are undergoing differentiation and proliferation6. 
In this video we describe an in vivo electroporation protocol for targeted delivery of genes, shRNA, and fluorescent dextrans to murine RGCs postnatally. This technique provides a cost effective, fast and relatively easy platform for efficient screening of candidate genes involved in several aspects of neural development including axon retraction, branching, lamination, regeneration and synapse formation at various stages of circuit development. In summary we describe here a valuable tool which will provide further insights into the molecular mechanisms underlying sensory map development.

Transfection of Mouse Retinal Ganglion Cells by in vivo Electroporation

We demonstrate an in vivo electroporation protocol for transfecting single or small clusters of retinal ganglion cells (RGCs) and other retinal cell types in postnatal mice over a wide range of ages. The ability to label and genetically manipulate postnatal RGCs in vivo is a powerful tool for developmental studies.

The targeting and refinement of RGC projections to the midbrain is a popular and powerful model system for studying how precise patterns of neural ...

Lectin-based Isolation and Culture of Mouse Embryonic Motoneurons

Spinal motoneurons develop towards postmitotic stages through early embryonic nervous system development and subsequently grow out dendrites and axons. Neuroepithelial cells of the neural tube that express Nkx6.1 are the unique precursor cells for spinal motoneurons1. Though postmitotic motoneurons move towards their final position and organize themselves into columns along the spinal tract2,3. More than 90% of all these differentiated and positioned motoneurons express the transcription factors Islet 1/2. They innervate the muscles of the limbs as well as those of the body and the inner organs. Among others, motoneurons typically express the high affinity receptors for brain derived neurotrophic factor (BDNF) and Neurotrophin-3 (NT-3), the tropomyosin-related kinase B and C (TrkB, TrkC). They do not express the tropomyosin-related kinase A (TrkA)4. Beside the two high affinity receptors, motoneurons do express the low affinity neurotrophin receptor p75NTR. The p75NTR can bind all neurotrophins with similar but lower affinity to all neurotrophins than the high affinity receptors would bind the mature neurotrophins. Within the embryonic spinal cord, the p75NTR is exclusively expressed by the spinal motoneurons5. This has been used to develop motoneuron isolation techniques to purify the cells from the vast majority of surrounding cells6. Isolating motoneurons with the help of specific antibodies (panning) against the extracellular domains of p75NTR has turned out to be an expensive method as the amount of antibody used for a single experiment is high due to the size of the plate used for panning. A much more economical alternative is the use of lectin. Lectin has been shown to specifically bind to p75NTR as well7. The following method describes an alternative technique using wheat germ agglutinin for a preplating procedure instead of the p75NTR antibody. The lectin is an extremely inexpensive alternative to the p75NTR antibody and the purification grades using lectin are comparable to that of the p75NTR antibody. Motoneurons from the embryonic spinal cord can be isolated by this method, survive and grow out neurites.

An alternative way of isolating mouse embryonic motoneurons from the spinal cord is described. The method takes into account the fact that lectin can bind to the low affinity nerve growth factor receptor p75NTR. This lectin-based preplating allows a purification similar to that with a specific antibody against the p75NTR.

Spinal motoneurons develop towards postmitotic stages through early embryonic nervous system development and subsequently grow out dendrites and axons. ...

Detection of Microregional Hypoxia in Mouse Cerebral Cortex by Two-photon Imaging of Endogenous NADH Fluorescence

The brain's ability to function at high levels of metabolic demand depends on continuous oxygen supply through blood flow and tissue oxygen diffusion. Here we present a visualized experimental and methodological protocol to directly visualize microregional tissue hypoxia and to infer perivascular oxygen gradients in the mouse cortex. It is based on the non-linear relationship between nicotinamide adenine dinucleotide (NADH) endogenous fluorescence intensity and oxygen partial pressure in the tissue, where observed tissue NADH fluorescence abruptly increases at tissue oxygen levels below 10 mmHg1. We use two-photon excitation at 740 nm which allows for concurrent excitation of intrinsic NADH tissue fluorescence and blood plasma contrasted with Texas-Red dextran. The advantages of this method over existing approaches include the following: it takes advantage of an intrinsic tissue signal and can be performed using standard two-photon in vivo imaging equipment; it permits continuous monitoring in the whole field of view with a depth resolution of ~50 &mu;m. We demonstrate that brain tissue areas furthest from cerebral blood vessels correspond to vulnerable watershed areas which are the first to become functionally hypoxic following a decline in vascular oxygen supply. This method allows one to image microregional cortical oxygenation and is therefore useful for examining the role of inadequate or restricted tissue oxygen supply in neurovascular diseases and stroke.

Here we describe a method to directly visualize microregional tissue hypoxia in the mouse cortex in vivo. It is based on concurrent two-photon imaging of nicotinamide adenine dinucleotide (NADH) and the cortical microcirculation. This method is useful for high resolution analysis of tissue oxygen supply.

The brain's ability to function at high levels of metabolic demand depends on continuous oxygen supply through blood flow and tissue oxygen diffusion. ...

In Vitro Modeling of Cancerous Neural Invasion: The Dorsal Root Ganglion Model

One way that solid tumors disseminate is through neural invasion. This route is well-known in cancers of the head and neck, prostate, and pancreas. These neurotropic cancer cells have a unique ability to migrate unidirectionally along nerves towards the central nervous system (CNS). The dorsal root ganglia (DRG)/cancer cell model is a three dimensional (3D) in vitro model frequently used for studying the interaction between neural stroma and cancer cells. In this model, mouse or human cancer cell lines are grown in ECM adjacent to preparations of freshly dissociated cultured DRG. In this article, the DRG isolation protocol from mice, and implantation in petri dishes for co-culturing with pancreatic cancer cells are demonstrated. Five days after implantation, the cancer cells made contact with the DRG neurites. Later, these cells formed bridgeheads to facilitate more extensive polarized, neurotropic migration of cancer cells.

In Vitro Modeling of Cancerous Neural Invasion: The Dorsal Root Ganglion Model

This video article shows the use of the dorsal root ganglia (DRG)/cancer cell model in pancreatic ductal adenocarcinoma.

One way that solid tumors disseminate is through neural invasion. This route is well-known in cancers of the head and neck, prostate, and pancreas. These ...

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.

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

Characterization and Isolation of Mouse Primary Microglia by Density Gradient Centrifugation

Microglia, the resident immune cells in the brain, are the first responders to inflammation or injury in the central nervous system. Recent research has revealed microglia to be dynamic, capable of assuming both pro-inflammatory and anti-inflammatory phenotypes. Both M1 (pro-inflammatory) and M2 (pro-reparative) phenotypes play an important role in neuroinflammatory conditions such as perinatal brain injury, and exhibit differing functions in response to certain environmental stimuli. The modulation of microglial activation has been noted to confer neuroprotection thus suggesting microglia may have therapeutic potential in brain injury. However, more research is required to better understand the role of microglia in disease, and this protocol facilitates that. The protocol described below combines a density gradient centrifugation process to reduce cellular debris, with magnetic separation, producing a highly pure sample of primary microglial cells that can be used for in vitro experimentation, without the need for 2-3 weeks culturing. Additionally, the characterization steps yield robust functional data about microglia, aiding studies to better our understanding of the polarization and priming of these cells, which has strong implications in the field of regenerative medicine.

A protocol for the isolation of primary microglia from murine brains is presented. This technique aids in furthering the current understanding of neurological conditions. Density gradient centrifugation and magnetic separation are combined to produce sufficient yield of a highly pure sample. Furthermore, we outline the steps for characterization of microglia.

Microglia, the resident immune cells in the brain, are the first responders to inflammation or injury in the central nervous system. Recent research has ...

Rapid and Specific Immunomagnetic Isolation of Mouse Primary Oligodendrocytes

The efficient and robust isolation and culture of primary oligodendrocytes (OLs) is a valuable tool for the in vitro study of the development of oligodendroglia as well as the biology of demyelinating diseases such as multiple sclerosis and Pelizaeus-Merzbacher-like disease (PMLD). Here, we present a simple and efficient selection method for the immunomagnetic isolation of stage three O4+ preoligodendrocytes cells from neonatal mice pups. Since immature OL constitute more than 80% of the rodent-brain white matter at postnatal day 7 (P7) this isolation method not only ensures high cellular yield, but also the specific isolation of OLs already committed to the oligodendroglial lineage, decreasing the possibility of isolating contaminating cells such as astrocytes and other cells from the mouse brain. This method is a modification of the techniques reported previously, and provides oligodendrocyte preparation purity above 80% in about 4 h.

We describe the immunomagnetic isolation of primary mouse oligodendrocytes, which allows the rapid and specific isolation of the cells for in vitro culture.

The efficient and robust isolation and culture of primary oligodendrocytes (OLs) is a valuable tool for the in vitro study of the development of ...

Neuronal Differentiation from Mouse Embryonic Stem Cells In vitro

The neural differentiation of mouse embryonic stem cells (mESCs) is a potential tool for elucidating the key mechanisms involved in neurogenesis and potentially aid in regenerative medicine. Here, we established an efficient and low cost method for neuronal differentiation from mESCs in vitro, using the strategy of combinatorial screening. Under the conditions defined here, the 2-day embryoid body formation + 6-day retinoic acid induction protocol permits fast and efficient differentiation from mESCs into neural precursor cells (NPCs), as seen by the formation of well-stacked and neurite-like A2lox and 129 derivatives that are Nestin positive. The healthy state of embryoid bodies and the timepoint at which retinoic acid (RA) is applied, as well as the RA concentrations, are critical in the process. In the subsequent differentiation from NPCs into neurons, N2B27 medium II (supplemented by Neurobasal medium) could better support the long term maintenance and maturation of neuronal cells. The presented method is highly efficiency, low cost and easy to operate, and can be a powerful tool for neurobiology and developmental biology research.

Here, we established a low cost and easy to operate method that directs fast and efficient differentiation from embryonic stem cells into neurons. This method is suitable for popularization among laboratories and can be a useful tool for neurological research.

The neural differentiation of mouse embryonic stem cells (mESCs) is a potential tool for elucidating the key mechanisms involved in neurogenesis and ...

Modeling Stroke in Mice: Focal Cortical Lesions by Photothrombosis

Stroke is a leading cause of death and acquired adult disability in developed countries. Despite extensive investigation for novel therapeutic strategies, there remain limited therapeutic options for stroke patients. Therefore, more research is needed for pathophysiological pathways such as post-stroke inflammation, angiogenesis, neuronal plasticity, and regeneration. Given the inability of in vitro models to reproduce the complexity of the brain, experimental stroke models are essential for the analysis and subsequent evaluation of novel drug targets for these mechanisms. In addition, detailed standardized models for all procedures are urgently needed to overcome the so-called replication crisis. As an effort within the ImmunoStroke research consortium, a standardized photothrombotic mouse model using an intraperitoneal injection of Rose Bengal and the illumination of the intact skull with a 561 nm laser is described. This model allows the performance of stroke in mice with allocation to any cortical region of the brain without invasive surgery; thus, enabling the study of stroke in various areas of the brain. In this video, the surgical methods of stroke induction in the photothrombotic model along with&#160;histological analysis are demonstrated.

Described here is the photothrombotic stroke model, where a stroke is produced through the intact skull by inducing permanent microvascular occlusion using laser illumination after administration of a photosensitive dye.

Stroke is a leading cause of death and acquired adult disability in developed countries. Despite extensive investigation for novel therapeutic strategies, ...

Generation of Human Brain Organoids for Mitochondrial Disease Modeling

Mitochondrial diseases represent the largest class of inborn errors of metabolism and are currently incurable. These diseases cause neurodevelopmental defects whose underlying mechanisms remain to be elucidated. A major roadblock is the lack of effective models recapitulating the early-onset neuronal impairment seen in the patients. Advances in the technology of induced pluripotent stem cells (iPSCs) enable the generation of three-dimensional (3D) brain organoids that can be used to investigate the impact of diseases on the development and organization of the nervous system. Researchers, including these authors, have recently introduced human brain organoids to model mitochondrial disorders. This paper reports a detailed protocol for the robust generation of human iPSC-derived brain organoids and their use in mitochondrial bioenergetic profiling and imaging analyses. These experiments will allow the use of brain organoids to investigate metabolic and developmental dysfunctions and may provide crucial information to dissect the neuronal pathology of mitochondrial diseases.

We describe a detailed protocol for the generation of human induced pluripotent stem cell-derived brain organoids and their use in modeling mitochondrial diseases.

Mitochondrial diseases represent the largest class of inborn errors of metabolism and are currently incurable. These diseases cause neurodevelopmental ...