Name: a cell culture model for studying the role of neuron-glia interactions in ischemia
Uploaded: 2020-11-14T14:00:00
Description: Watch this Scientific Journal Video about A Cell Culture Model for Studying the Role of Neuron-Glia Interactions in Ischemia at JoVE.com

The authors acknowledge the funding support by Funda&#231;&#227;o para a Ci&#234;ncia e a Tecnologia through Projects UIDB/00709/2020, POCI-01-0145-FEDER-029311 and the fellowship SFRH/BD/135936/2018 to JP, by &#8216;&#8216;Programa Operacional do Centro, Centro 2020&#8221; through the project CENTRO-01-0145-FEDER-000013 and funding to the PPBI-Portuguese Platform of BioImaging through the Project POCI-01-0145-FEDER-022122.

All animals used were bred at the CICS-UBI Health Science Research Centre in accordance with the national ethical requirements for animal research and with the European Convention for the Protection of Vertebrate Animals Used for Experimental and Other Scientific Purposes (Directive 2010/63/EU).
1. Rat embryo cortex primary cell culture
<ol>
	<li>Culture medium preparation
	<ol>
		<li>Prepare the Neurobasal Medium (NBM) by adding the following supplements: 2% B27, 0.5 mM glutamine, 25 &#181;...

<ol>
	<li>Donkor, E. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stroke+in+the+21(st)+Century:+A+Snapshot+of+the+Burden,+Epidemiology,+and+Quality+of+Life.">Stroke in the 21(st) Century: A Snapshot of the Burden, Epidemiology, and Quality of Life.</a> Stroke Research and Treatment. 2018, 3238165 (2018).</li><li>Dirnagl, U., Iadecola, C., Moskowitz, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathobiology+of+ischaemic+stroke:+an+integrated+view.">Pathobiology of ischaemic stroke: an integrated view.</a> Trends in Neurosciences. 22 (9), 391-397 (1999).</li><li>Woodruff, T. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathophysiology,+treatment,+and+animal+and+cellular+models+of+human+ischemic+stroke.">Pathophysiology, treatment, and animal and cellular models of human ischemic stroke.</a> Molecular Neurodegeneration. 6 (1), 11 (2011).</li><li>Berezowski, V., Fukuda, A. M., Cecchelli, R., Badaut, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial+cells+and+astrocytes:+a+concerto+en+duo+in+ischemic+pathophysiology.">Endothelial cells and astrocytes: a concerto en duo in ischemic pathophysiology.</a> International Journal of Cell Biology. 2012, 176287 (2012).</li><li>Roque, C., Baltazar, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+Astrocytes+on+the+Injury+Induced+by+In+vitro+Ischemia.">Impact of Astrocytes on the Injury Induced by In vitro Ischemia.</a> Cellular and Molecular Neurobiology. 37 (8), 1521-1528 (2017).</li><li>Ransom, B. R., Ransom, C. 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P., Tymianski, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postsynaptic+mechanisms+of+excitotoxicity:+Involvement+of+postsynaptic+density+proteins,+radicals,+and+oxidant+molecules.">Postsynaptic mechanisms of excitotoxicity: Involvement of postsynaptic density proteins, radicals, and oxidant molecules.</a> Neuroscience. 158 (1), 293-300 (2009).</li><li>Basic Kes, V., Simundic, A. M., Nikolac, N., Topic, E., Demarin, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pro-inflammatory+and+anti-inflammatory+cytokines+in+acute+ischemic+stroke+and+their+relation+to+early+neurological+deficit+and+stroke+outcome.">Pro-inflammatory and anti-inflammatory cytokines in acute ischemic stroke and their relation to early neurological deficit and stroke outcome.</a> Clinical Biochemistry. 41 (16-17), 1330-1334 (2008).</li><li>Gursoy-Ozdemir, Y., Can, A., Dalkara, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reperfusion-induced+oxidative/nitrative+injury+to+neurovascular+unit+after+focal+cerebral+ischemia.">Reperfusion-induced oxidative/nitrative injury to neurovascular unit after focal cerebral ischemia.</a> Stroke. 35 (6), 1449-1453 (2004).</li><li>Cekanaviciute, 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=Astrocytic+transforming+growth+factor-beta+signaling+reduces+subacute+neuroinflammation+after+stroke+in+mice.">Astrocytic transforming growth factor-beta signaling reduces subacute neuroinflammation after stroke in mice.</a> Glia. 62 (8), 1227-1240 (2014).</li><li>Huang, 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=Glial+scar+formation+occurs+in+the+human+brain+after+ischemic+stroke.">Glial scar formation occurs in the human brain after ischemic stroke.</a> International Journal of Medical Sciences. 11 (4), 344-348 (2014).</li><li>Rodriguez-Grande, 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=The+acute-phase+protein+PTX3+is+an+essential+mediator+of+glial+scar+formation+and+resolution+of+brain+edema+after+ischemic+injury.">The acute-phase protein PTX3 is an essential mediator of glial scar formation and resolution of brain edema after ischemic injury.</a> Journal of Cerebral Blood Flow &amp; Metabolism. 34 (3), 480-488 (2014).</li><li>Cheng, X., 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=Dynamic+Alterations+of+Brain+Injury,+Functional+Recovery,+and+Metabolites+Profile+after+Cerebral+Ischemia/Reperfusion+in+Rats+Contributes+to+Potential+Biomarkers.">Dynamic Alterations of Brain Injury, Functional Recovery, and Metabolites Profile after Cerebral Ischemia/Reperfusion in Rats Contributes to Potential Biomarkers.</a> Journal of Molecular Neuroscience. 70 (5), 667-676 (2020).</li><li>Wang, X., 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=Dual+role+of+intrauterine+immune+challenge+on+neonatal+and+adult+brain+vulnerability+to+hypoxia-ischemia.">Dual role of intrauterine immune challenge on neonatal and adult brain vulnerability to hypoxia-ischemia.</a> Journal of Neuropathology &amp; Experimental Neurology. 66 (6), 552-561 (2007).</li><li>Panahpour, H., Farhoudi, M., Omidi, Y., Mahmoudi, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+In+vivo+Assessment+of+Blood-Brain+Barrier+Disruption+in+a+Rat+Model+of+Ischemic+Stroke.">An In vivo Assessment of Blood-Brain Barrier Disruption in a Rat Model of Ischemic Stroke.</a> Journal of Visualized Experiments. (133), e57156 (2018).</li><li>Laake, J. H., Haug, F. M., Wieloch, T., Ottersen, O. P. <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+in+vitro+model+of+ischemia+based+on+hippocampal+slice+cultures+and+propidium+iodide+fluorescence.">A simple in vitro model of ischemia based on hippocampal slice cultures and propidium iodide fluorescence.</a> Brain Research Protocols. 4 (2), 173-184 (1999).</li><li>Cimarosti, H., Kantamneni, S., Henley, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ischaemia+differentially+regulates+GABA(B)+receptor+subunits+in+organotypic+hippocampal+slice+cultures.">Ischaemia differentially regulates GABA(B) receptor subunits in organotypic hippocampal slice cultures.</a> Neuropharmacology. 56 (8), 1088-1096 (2009).</li><li>Cho, 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=Spatiotemporal+evidence+of+apoptosis-mediated+ischemic+injury+in+organotypic+hippocampal+slice+cultures.">Spatiotemporal evidence of apoptosis-mediated ischemic injury in organotypic hippocampal slice cultures.</a> Neurochemistry International. 45 (1), 117-127 (2004).</li><li>Dong, W. Q., Schurr, A., Reid, K. H., Shields, C. B., West, 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=The+Rat+Hippocampal+Slice+Preparation+as+an+Invitro+Model+of+Ischemia.">The Rat Hippocampal Slice Preparation as an Invitro Model of Ischemia.</a> Stroke. 19 (4), 498-502 (1988).</li><li>Tamura, R., 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=Neuroprotective+effects+of+adenosine+deaminase+in+the+striatum.">Neuroprotective effects of adenosine deaminase in the striatum.</a> Journal of Cerebral Blood Flow and Metabolism. 36 (4), 709-720 (2016).</li><li>Dennis, S. H., 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=Oxygen/Glucose+Deprivation+Induces+a+Reduction+in+Synaptic+AMPA+Receptors+on+Hippocampal+CA3+Neurons+Mediated+by+mGluR1+and+Adenosine+A(3)+Receptors.">Oxygen/Glucose Deprivation Induces a Reduction in Synaptic AMPA Receptors on Hippocampal CA3 Neurons Mediated by mGluR1 and Adenosine A(3) Receptors.</a> Journal of Neuroscience. 31 (33), 11941-11952 (2011).</li><li>Bar El, Y., Kanner, S., Barzilai, A., Hanein, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activity+changes+in+neuron-astrocyte+networks+in+culture+under+the+effect+of+norepinephrine.">Activity changes in neuron-astrocyte networks in culture under the effect of norepinephrine.</a> PLoS One. 13 (10), (2018).</li><li>Kuszczyk, M. 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=Blocking+the+Interaction+between+Apolipoprotein+E+and+A+beta+Reduces+Intraneuronal+Accumulation+of+A+beta+and+Inhibits+Synaptic+Degeneration.">Blocking the Interaction between Apolipoprotein E and A beta Reduces Intraneuronal Accumulation of A beta and Inhibits Synaptic Degeneration.</a> American Journal of Pathology. 182 (5), 1750-1768 (2013).</li><li>Skaper, S. D., Facci, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Central+Nervous+System+Neuron-Glia+co-Culture+Models+and+Application+to+Neuroprotective+Agents.">Central Nervous System Neuron-Glia co-Culture Models and Application to Neuroprotective Agents.</a> Methods in Molecular Biology. 1727, 63-80 (2018).</li><li>Fang, 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=Effects+of+astrocyte+on+neuronal+outgrowth+in+a+layered+3D+structure.">Effects of astrocyte on neuronal outgrowth in a layered 3D structure.</a> BioMedical Engineering OnLine. 18 (1), 74 (2019).</li><li>Fernando, G., Yamila, R., Cesar, G. J., Ramon, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuroprotective+Effects+of+neuroEPO+Using+an+In+vitro+Model+of+Stroke.">Neuroprotective Effects of neuroEPO Using an In vitro Model of Stroke.</a> Behavioral Sciences. 8 (2), (2018).</li><li>Zhao, L. R., Willing, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhancing+endogenous+capacity+to+repair+a+stroke-damaged+brain:+An+evolving+field+for+stroke+research.">Enhancing endogenous capacity to repair a stroke-damaged brain: An evolving field for stroke research.</a> Progress in Neurobiology. 163, 5-26 (2018).</li><li>Crandall, J. E., Jacobson, M., Kosik, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ontogenesis+of+microtubule-associated+protein+2+(MAP2)+in+embryonic+mouse+cortex.">Ontogenesis of microtubule-associated protein 2 (MAP2) in embryonic mouse cortex.</a> Brain Research. 393 (1), 127-133 (1986).</li><li>Chamak, B., Fellous, A., Glowinski, J., Prochiantz, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MAP2+expression+and+neuritic+outgrowth+and+branching+are+coregulated+through+region-specific+neuro-astroglial+interactions.">MAP2 expression and neuritic outgrowth and branching are coregulated through region-specific neuro-astroglial interactions.</a> Journal of Neuroscience. 7 (10), 3163-3170 (1987).</li><li>Almeida, A., Medina, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+rapid+method+for+the+isolation+of+metabolically+active+mitochondria+from+rat+neurons+and+astrocytes+in+primary+culture.">A rapid method for the isolation of metabolically active mitochondria from rat neurons and astrocytes in primary culture.</a> Brain Research Protocols. 2 (3), 209-214 (1998).</li><li>Bessa, 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=GPER:+A+new+tool+to+protect+dopaminergic+neurons.">GPER: A new tool to protect dopaminergic neurons.</a> Biochim Biophys Acta. 1852 (10), 2035-2041 (2015).</li><li>De Simone, U., Caloni, F., Gribaldo, L., Coccini, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+Co-culture+Model+of+Neurons+and+Astrocytes+to+Test+Acute+Cytotoxicity+of+Neurotoxic+Compounds.">Human Co-culture Model of Neurons and Astrocytes to Test Acute Cytotoxicity of Neurotoxic Compounds.</a> International Journal of Toxicology. 36 (6), 463-477 (2017).</li><li>Yang, L., Shah, K. K., Abbruscato, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+in+vitro+model+of+ischemic+stroke.">An in vitro model of ischemic stroke.</a> Methods in Molecular Biology. 814, 451-466 (2012).</li><li>Holloway, P. M., Gavins, F. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+Ischemic+Stroke+In+Vitro:+Status+Quo+and+Future+Perspectives.">Modeling Ischemic Stroke In Vitro: Status Quo and Future Perspectives.</a> Stroke. 47 (2), 561-569 (2016).</li><li>Rossi, D. J., Brady, J. 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The method here described consists of the astrocyte and neuron isolation from rat embryonic cortical tissue, allowing the establishment of neuron- or astrocyte-enriched cultures or neuron-glia cultures. It was adapted from a previous study of our group5, where the cortical neuron&#8211;glia and neuron-enriched embryonic cultures isolation were described and the two cultures characterized. Using these cultures, Roque et al. found that astrocytes play a key role in responding to an ischemic damage a...

According to data from the World Health Organization, about 5.5 million people die every year from ischemic stroke1. This condition is characterized by the interruption of blood flow to a certain brain region, resulting in a reversible or irreversible loss in the supply of oxygen and nutrients to the tissue, which alters tissue function and leads to mitochondrial dysfunction, calcium dysregulation, glutamate excitotoxicity, inflammation and cell loss2,3.
Apart from vascular cells, neuronal and glial cells are involved in the pathophysiology of the ischemic stroke4. In particular, astrocytes are essential to the maintenance of neurons and recently were shown to play a critical role in the response to the ischemic lesion5. This type of glial cell performs functions of structural support, defence against oxidative stress, synthesis of neurotransmitters, stabilization of cell-cell communication, among others6. Along with neurons, astrocytes play a direct role in synaptic transmission, regulating the release of molecules such as adenosine triphosphate, gamma-aminobutyric acid and glutamate7. Part of the injury induced by ischemia is caused by the excessive release of glutamate and its accumulation at the synaptic cleft, leading to the overactivation of N-methyl-D-aspartate receptors, activating downstream signalling cascades, ultimately resulting in excitotoxicity8. Since astrocytes are able to remove glutamate from the synaptic cleft and convert it into glutamine, they are crucial in defending against excitotoxicity, thereby exerting a neuroprotective effect on ischemia. These cells also play a role in ischemia-induced neuroinflammation. After the ischemic insult, activated astrocytes undergo morphologic changes (hypertrophy), proliferate, and show an increase in glial fibrillary acidic protein (GFAP) expression. They can become reactive (astrogliosis), releasing pro-inflammatory cytokines such as tumour necrosis factor-&#945;, interleukin-1&#945; and interleukin-1&#946;, and producing free radicals, including nitric oxide and superoxide, which in turn can induce neuronal death9,10. In contrast, reactive astrocytes may also play a neuroprotective effect, since they release anti-inflammatory cytokines, such as transforming growth factor-&#946;, that is upregulated after stroke11. Moreover, they can generate a glial scar, which can limit tissue regeneration by inhibiting axonal sprouting; however, this glial scar can isolate the injury site from viable tissue, thus preventing a cascading wave of uncontrolled tissue damage12,13.
Thus, it is imperative to establish models that allow studying neuron-glia interactions under an ischemic injury in order to find therapeutic strategies that limit or reverse the effects of ischemic injury. Compared to other models used to study ischemic injury, namely in vivo models14,15,16, organotypic cultures17,18,19 and acute brain slices20,21,22, primary cell cultures are less complex, which makes possible the study of individual contributions of each cell type in the pathophysiology of ischemic stroke and how each cell type responds to possible therapeutic targets. Typically, in order to study the interactions between neuron-enriched cultures and astrocyte-enriched cultures, neurons and glial cells of postnatal origin are used23,24, or postnatal glial cells and embryonic neurons25,26. Herein is proposed a simple approach to establish neuron- or astrocyte-enriched cultures and neuron-glia cultures from the same tissue. These primary cells are obtained from rat embryonic cortex, a region frequently affected by stroke27,28. Moreover, the dissociation of the tissue is performed only by a mechanical procedure. Therefore, this protocol allows isolating cells in the same stage of development, in a fast and inexpensive way, and with high performance and reproducibility.
The crosstalk between astrocytes and neurons can be explored using a co-culture system in which neurons cultured in coverslips are maintained in contact with a monolayer of astrocytes seeded in multiwell plates. Small paraffin spheres can be used to ensure the separation of the two cell cultures. This approach allows independent manipulation of each cell type before they are brought into contact. For example, it is possible to silence a specific gene in astrocytes and see how it can influence the neuronal vulnerability or protection against ischemic-induced damage. An established method to induce ischemic-like conditions in vitro is oxygen and glucose deprivation (OGD)3, which consists in replacing the regular atmosphere (95% air and 5% CO2) by an anoxic atmosphere (95% N2 and 5% CO2), associated with the omission of glucose.
The method described is suitable for studying the interactions between neurons and astrocytes in the context of ischemic stroke, in a simple, fast, reproducible and inexpensive way.

<table>
	<tbody>
		<tr>
			<td>24 -well culture plates</td>
			<td>Thermo Fischer Scientific</td>
			<td>142475</td>
			<td></td>
		</tr>
		<tr>
			<td>95% N2/5% CO2 gas cylinder</td>
			<td>ArL&#237;quido</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mouse conjugated to Alexa Fluor 488</td>
			<td>Invitrogen</td>
			<td>A11001</td>
			<td>1/1000 dilution; incubation period - 1 h at room temperature</td>
		</tr>
		<tr>
			<td>Anti-rabbit conjugated to Alexa Fluor 546</td>
			<td>Invitrogen</td>
			<td>A11010</td>
			<td>1/1000 dilution; incubation period - 1 h at room temperature</td>
		</tr>
		<tr>
			<td>B27 supplement (50x)</td>
			<td>Gibco</td>
			<td>17504-044</td>
			<td></td>
		</tr>
		<tr>
			<td>Dako Fluorescence Mounting Medium</td>
			<td>Dako</td>
			<td>S3023</td>
			<td></td>
		</tr>
		<tr>
			<td>D-glucose anhydrous</td>
			<td>Fisher Scientific</td>
			<td>G/0450/60</td>
			<td>3.4 g/L</td>
		</tr>
		<tr>
			<td>Epifluorescence microscope</td>
			<td>Zeiss</td>
			<td>AxioObserver Z1x</td>
			<td>63x objective</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum (FBS)</td>
			<td>Biochrom</td>
			<td>S0615</td>
			<td>10%</td>
		</tr>
		<tr>
			<td>Gentamicin</td>
			<td>Sigma-Aldrich</td>
			<td>G1272</td>
			<td>120 &#181;g/mL</td>
		</tr>
		<tr>
			<td>Glutamate</td>
			<td>Sigma-Aldrich</td>
			<td>G8415</td>
			<td>25&#181;M</td>
		</tr>
		<tr>
			<td>Glutamine</td>
			<td>Sigma-Aldrich</td>
			<td>G3126</td>
			<td>0.5 mM</td>
		</tr>
		<tr>
			<td>Hoechst 33342</td>
			<td>Invitrogen</td>
			<td>H1399</td>
			<td>2 &#181;M; incubation period - 10 min at room temperature</td>
		</tr>
		<tr>
			<td>Hypoxia incubation chamber</td>
			<td>Stemcell Technologies</td>
			<td>27310</td>
			<td>Chamber used for OGD induction</td>
		</tr>
		<tr>
			<td>Insulin from bovine pancreas</td>
			<td>Sigma-Aldrich</td>
			<td>I5500</td>
			<td>5 mg/L</td>
		</tr>
		<tr>
			<td>Ketamine</td>
			<td>Sigma-Aldrich</td>
			<td>K-002</td>
			<td>87.5 mg/Kg</td>
		</tr>
		<tr>
			<td>Minimum Essential Medium Eagle medium</td>
			<td>Sigma-Aldrich</td>
			<td>M0268</td>
			<td>warm up to 37 &#176;C before use</td>
		</tr>
		<tr>
			<td>Mouse Anti-MAP2</td>
			<td>Santa Cruz Biotechnology</td>
			<td>Sc-74421</td>
			<td>1/500 dilution; incubation period overnight at 4 &#176;C</td>
		</tr>
		<tr>
			<td>Neurobasal medium</td>
			<td>Gibco</td>
			<td>21103-049</td>
			<td>warm up to 37 &#176;C before use</td>
		</tr>
		<tr>
			<td>Paraffin pastilles for histology</td>
			<td>Sigma-Aldrich</td>
			<td>1.07164</td>
			<td>Solidification point 56-58&#176;C</td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>Sigma -Aldrich</td>
			<td>P6148</td>
			<td>4% in PBS</td>
		</tr>
		<tr>
			<td>Penicilin/Streptomycin</td>
			<td>Biochrom</td>
			<td>A 2213</td>
			<td>penicillin (12U/mL) /streptomycin (12&#181;g/mL)</td>
		</tr>
		<tr>
			<td>Poly-D-lysine</td>
			<td>Sigma-Aldrich</td>
			<td>P1024</td>
			<td></td>
		</tr>
		<tr>
			<td>Rabbit Anti-GFAP</td>
			<td>DAKO</td>
			<td>Z0334</td>
			<td>1/2000 dilution; incubation period overnight at 4 &#176;C</td>
		</tr>
		<tr>
			<td>Sodium hydrogen carbonate</td>
			<td>Fisher Scientific</td>
			<td>S/4240/60</td>
			<td>2.2g/L</td>
		</tr>
		<tr>
			<td>Xylazine</td>
			<td>Sigma-Aldrich</td>
			<td>X1126</td>
			<td>12 mg/Kg</td>
		</tr>
	</tbody>
</table>

a cell culture model for studying the role of neuron-glia interactions in ischemia

Ischemic stroke is a clinical condition characterized by hypoperfusion of brain tissue, leading to oxygen and glucose deprivation, and the consequent neuronal loss. Numerous evidence suggests that the interaction between glial and neuronal cells exert beneficial effects after an ischemic event. Therefore, to explore potential protective mechanisms, it is important to develop models that allow studying neuron-glia interactions in an ischemic environment. Herein we present a simple approach to isolate astrocytes and neurons from the rat embryonic cortex, and that by using specific culture media, allows the establishment of neuron- or astrocyte-enriched cultures or neuron-glia cultures with high yield and reproducibility.
To study the crosstalk between astrocytes and neurons, we propose an approach based on a co-culture system in which neurons cultured in coverslips are maintained in contact with a monolayer of astrocytes plated in multiwell plates. The two cultures are maintained apart by small paraffin spheres. This approach allows the independent manipulation and the application of specific treatments to each cell type, which represents an advantage in many studies.
To simulate what occurs during an ischemic stroke, the cultures are subjected to an oxygen and glucose deprivation protocol. This protocol represents a useful tool to study the role of neuron-glia interactions in ischemic stroke.

To characterize the cultures, immunocytochemistry to assess the number of cells that expressed GFAP or MAP2, widely used markers of astrocytes and neurons (Figure 2), was performed in each type of cortical culture. This analysis revealed that astrocyte-enriched cultures presented 97% of the cells expressing GFAP (Figure 2A). Regarding the neuron-enriched culture 78% of the cells expressed MAP2, 4% of the cells expressed GFAP, and 18% of the cells were both GFAP ...

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A Cell Culture Model for Studying the Role of Neuron-Glia Interactions in Ischemia

Here, we present a simple approach using specific culture media that allows the establishment of neuron- and astrocyte-enriched cultures, or neuron-glia cultures from the embryonic cortex, with high yield and reproducibility.

Ischemic stroke is a clinical condition characterized by hypoperfusion of brain tissue, leading to oxygen and glucose deprivation, and the consequent ...

Ischemic stroke is a clinical condition characterized by hypoperfusion of brain tissue and results in neuronal loss. Numerous evidences suggest that the interaction between glia and urinal cells exert the pressure effects after an ischemic event. In order to explore potential protective mechanisms, it is important to develop models that allow studying neuron-glia interactions in an ischemic environment.Here we present a simple approach to isolate astrocytes and neurons from rat embryonic cortex, and that by using specific cultural medium allows the establishment of neuron or astrocyte-enriched cultures or neo-glia cultures with high yield and reproducibility. To study the crosstalk between astrocytes and neurons, we propose an approach, based on a co-culture system, in which neurons cultured in cover slips are maintained in contact with a monolayer of astrocytes plated in multi-well plates. The two cultures are maintained a part by small paraffin spheres.This approach allows independent manipulation and the application of specific treatment to each cell type, which represents an advantage in many studies. To simulate what occurs during an ischemic stroke, the cultures are subjected to an oxygen and glucose deprivation protocol. This protocol represents a useful tool to study the role of neuron-glia interactions in ischemic stroke.Start with rat embryonic cortex insulation. The embryos were obtained from a family of rats at 15 days of gestation and are placed in a sterile Falcon tube containing PBS. Still inside the yolk sachet embryos are placed inside a petri dish containing cold PBS.With the help of scissors and tweezers, the yolk sac is broken, and the embryo is removed and placed in another petri dish containing cold PBS over an ice pack. It is necessary to be very careful when breaking the yolk sac not to damage the embryo. Position the embryo under a dissecting microscope, gently fix the embryo using a twizzer.The initial incision should be parallel to the cortex. Be careful not to decapitate the animal. The scalp and are carefully removed not to damage the cortical brain tissue.This next incision separates the cortex. Remove the blood vessels present in the tissue. Finally, using a pipette, transfer the cortical tissue to a Falcon tube with PBS.The single cell suspension is obtained through mechanical digestion of the cortical brain tissue using tips with decreasing diameter. Make sure that the tissue is well homogenized After the digestion, centrifuge the material at 400 Gs for three minutes. Discard the supernatant, and resuspend the sediment in culture medium, previously warmed to 37 degrees.Calculate the total number of cells present in the suspension using a Neubauer chamber and preparate the dilution for the adequate cell density. Finally, seed the cells in the multi-well and incubate at 37 degrees. In order to prepare the material for the co-culture system, heat the paraffin in a heating block until it becomes liquid.Then, with the help of a stereo glass Pasteur pipette prepare small spheres over the cover slips that were previously placed in a multi-well, and coated with Poly-D-Lysine. 24 hours before the two cultures are brought in contact, change the culture medium of neurons and astrocytes to supplement it NBM with or without heat inactivated FBS. When the two cultures are ready to use, transfer the neuron, seated in the cover slips with paraffin spheres to wells containing astrocytes using a tweezers previously immersed in 70%ethanol.After placing both cell types in contact, wait eight to 12 hours, and then start the different stimuli and procedures. The oxygen and glucose deprivation is performed in a culture with seven days of growth. Remove the culture medium, and wash the cells two times with HBSS medium without glucose supplementation.Be sure that all the medium containing glucose is washed. Seal the Hypoxia Chamber and add the gas mix containing 95%nitrogen and 5%carbon dioxide for four minute with a flow of 20 liters for minutes in order to replace the oxygen present inside the chamber. Then, stop the flow and place the Hypoxia Chamber in an incubator at 37 degrees.After the period of oxygen and glucose deprivation, replace the medium, HBSS without glucose supplementation with the appropriate culture medium for the remaining procedures and incubate the cells at 37 degrees. In order to characterize the type of cortical culture, we performed immunohistochemistry in the three types of cortical cultures to assess the number of cells that expressed GFPA or MAP2, which are markers widely used for astrocytic and neuronal cells respectively. These analysis revealed that when this protocol, we were able to obtain a pure enriched culture of astrocytes with about 97%of the cells expressing GFAP.Regarding the neuron-enriched culture, we verified about 78%of the cells expressing MAP2. However we identify about 18%of GFAP and MAP2 negative cells. For the neuron-glia cortical culture, It was observed that about 49%of the cells are MAP2 positive.31%are GFAP positive. And 20%they're not liable for GFAP nor MAP2. Seven days after the cortical culture establishment, the neuron-glia culture and the neuron-enriched culture were subjected to an OGD procedure for 4 and 6 hours.After this procedure, cells were labeled with MAP2 and then the number of MAP2 positive cells were quantified using fluorescence microscopy. In neuron-glia culture, it was observed a decrease of about 30%in the number of the neurons, when the culture was submitted to an OGD period of 4 hours. After an OGD period of 6 hours, the extension of the lesion increases, reaching about 60%of neuronal loss.Regarding the enriched culture of neurons exposed to OGD, it was observed about 41%and 64%decrease in the number of MAP2 cells. Moreover, it was observed that in the neuron-enriched culture, there was a slight increase in the injury extension when compared to the neuron-glia culture also exposed to OGD during 4 hours. In conclusion, here represent an in vitro model to study ischemic stroke established in a simple, fast and expensive and reproducible way.Additionally, the method described also allows to implement neurons and astrocyte-enriched primary cultures, but also a neuron-glia culture. Thus, providing a great in-vitro model for modeling several brain diseases with a higher level of complexity, than immortalized cell lines and pure neuronal or glial cultures.

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Research

JoVE Journal

Neuroscience

A Procedure for Studying the Footshock-Induced Reinstatement of Cocaine Seeking in Laboratory Rats

The most insidious aspect of drug addiction is the high propensity for relapse. Animal models of relapse, known as reinstatement procedures, have been used extensively to study the neurobiology and phenomenology of relapse to drug use. Although procedural variations have emerged over the past several decades, the most conventional reinstatement procedures are based on the drug self-administration (SA) model. In this model, an animal is trained to perform an operant response to obtain drug. Subsequently, the behavior is extinguished by withholding response-contingent reinforcement. Reinstatement of drug seeking is then triggered by a discrete event, such as an injection of the training drug, re-exposure to drug-associated cues, or exposure to a stressor 1.
Reinstatement procedures were originally developed to study the ability of acute non-contingent exposure to the training drug to reinstate drug seeking in rats and monkeys 1, 2. Reinstatement procedures have since been modified to study the role of environmental stimuli, including drug-associated cues and exposure to various forms of stress, in relapse to drug seeking 1, 3, 4.
Over the past 15 years, a major focus of the reinstatement literature has been on the role of stress in drug relapse. One of the most commonly used forms of stress for studying this relationship is acute exposures to mild, intermittent, electric footshocks. The ability of footshock stress to induce reinstatement of drug seeking was originally demonstrated by Shaham and colleagues (1995) in rats with a history of intravenous heroin SA5. Subsequently, the effect was generalized to rats with histories of intravenous cocaine, methamphetamine, and nicotine SA, as well as oral ethanol SA 3, 6.
Although footshock-induced reinstatement of drug seeking can be achieved reliably and robustly, it is an effect that tends to be sensitive to certain parametrical variables. These include the arrangement of extinction and reinstatement test sessions, the intensity and duration of footshock stress, and the presence of drug-associated cues during extinction and testing for reinstatement. Here we present a protocol for footshock-induced reinstatement of cocaine seeking that we have used with consistent success to study the relationship between stress and cocaine seeking.

Animal models of relapse, known as reinstatement procedures, have been used extensively to study the role of stress in relapse to drug seeking. Here, we report on a method for inducing the reinstatement of cocaine seeking in laboratory rats via acute exposures to mild, intermittent electric footshock.

The most insidious aspect of drug addiction is the high propensity for relapse.  Animal models of relapse, known as reinstatement procedures, have been ...

Isolation and Culture of Neural Crest Cells from Embryonic Murine Neural Tube

The embryonic neural crest (NC) is a multipotent progenitor population that originates at the dorsal aspect of the neural tube, undergoes an epithelial to mesenchymal transition (EMT) and migrates throughout the embryo, giving rise to diverse cell types 1-3. NC also has the unique ability to influence the differentiation and maturation of target organs4-6. When explanted in vitro, NC progenitors undergo self-renewal, migrate and differentiate into a variety of tissue types including neurons, glia, smooth muscle cells, cartilage and bone. 
NC multipotency was first described from explants of the avian neural tube7-9. In vitro isolation of NC cells facilitates the study of NC dynamics including proliferation, migration, and multipotency. Further work in the avian and rat systems demonstrated that explanted NC cells retain their NC potential when transplanted back into the embryo10-13. Because these inherent cellular properties are preserved in explanted NC progenitors, the neural tube explant assay provides an attractive option for studying the NC in vitro. 
To attain a better understanding of the mammalian NC, many methods have been employed to isolate NC populations. NC-derived progenitors can be cultured from post-migratory locations in both the embryo and adult to study the dynamics of post-migratory NC progenitors11,14-20, however isolation of NC progenitors as they emigrate from the neural tube provides optimal preservation of NC cell potential and migratory properties13,21,22. Some protocols employ fluorescence activated cell sorting (FACS) to isolate a NC population enriched for particular progenitors11,13,14,17. However, when starting with early stage embryos, cell numbers adequate for analyses are difficult to obtain with FACS, complicating the isolation of early NC populations from individual embryos. Here, we describe an approach that does not rely on FACS and results in an approximately 96% pure NC population based on a Wnt1-Cre activated lineage reporter23. 
The method presented here is adapted from protocols optimized for the culture of rat NC11,13. The advantages of this protocol compared to previous methods are that 1) the cells are not grown on a feeder layer, 2) FACS is not required to obtain a relatively pure NC population, 3) premigratory NC cells are isolated and 4) results are easily quantified. Furthermore, this protocol can be used for isolation of NC from any mutant mouse model, facilitating the study of NC characteristics with different genetic manipulations. The limitation of this approach is that the NC is removed from the context of the embryo, which is known to influence the survival, migration and differentiation of the NC2,24-28.

Isolation of embryonic neural crest from the neural tube facilitates the use of in vitro methods for studying migration, self-renewal, and multipotency of neural crest.

The embryonic neural crest (NC) is a multipotent progenitor population that originates at the dorsal aspect of the neural tube, undergoes an epithelial to ...

Dual Electrophysiological Recordings of Synaptically-evoked Astroglial and Neuronal Responses in Acute Hippocampal Slices

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs through activation of their ion channels and neurotransmitter receptors, and process information in part through activity-dependent release of gliotransmitters. Furthermore, astrocytes constitute the main uptake system for glutamate, contribute to potassium spatial buffering, as well as to GABA clearance. These cells therefore constantly monitor synaptic activity, and are thereby sensitive indicators for alterations in synaptically-released glutamate, GABA and extracellular potassium levels. Additionally, alterations in astroglial uptake activity or buffering capacity can have severe effects on neuronal functions, and might be overlooked when characterizing physiopathological situations or knockout mice. Dual recording of neuronal and astroglial activities is therefore an important method to study alterations in synaptic strength associated to concomitant changes in astroglial uptake and buffering capacities. Here we describe how to prepare hippocampal slices, how to identify stratum radiatum astrocytes, and how to record simultaneously neuronal and astroglial electrophysiological responses. Furthermore, we describe how to isolate pharmacologically the synaptically-evoked astroglial currents.

The preparation of acute brain slices from isolated hippocampi, as well as the simultaneous electrophysiological recordings of astrocytes and neurons in stratum radiatum during stimulation of schaffer collaterals is described. The pharmacological isolation of astroglial potassium and glutamate transporter currents is demonstrated.

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs ...

Methods for Studying the Mechanisms of Action of Antipsychotic Drugs in Caenorhabditis elegans

Caenorhabditis elegans is a simple genetic organism amenable to large-scale forward and reverse genetic screens and chemical genetic screens. The C. elegans genome includes potential antipsychotic drug (APD) targets conserved in humans, including genes encoding proteins required for neurotransmitter synthesis and for synaptic structure and function. APD exposure produces developmental delay and/or lethality in nematodes in a concentration-dependent manner. These phenotypes are caused, in part, by APD-induced inhibition of pharyngeal pumping1,2. Thus, the developmental phenotype has a neuromuscular basis, making it useful for pharmacogenetic studies of neuroleptics. Here we demonstrate detailed procedures for testing APD effects on nematode development and pharyngeal pumping. For the developmental assay, synchronized embryos are placed on nematode growth medium (NGM) plates containing APDs, and the stages of developing animals are then scored daily. For the pharyngeal pumping rate assay, staged young adult animals are tested on NGM plates containing APDs. The number of pharyngeal pumps per unit time is recorded, and the pumping rate is calculated. These assays can be used for studying many other types of small molecules or even large molecules.

Methods for Studying the Mechanisms of Action of Antipsychotic Drugs in Caenorhabditis elegans

Approaches for testing the effects of antipsychotic drugs (APDs) in Caenorhabditis elegans are demonstrated. Assays are described for testing drug effects on development and viability and on pharyngeal pumping rate. These methods are also applicable for pharmacogenetic experiments with drug classes other than APDs.

Caenorhabditis elegans is a simple genetic organism amenable to  large-scale forward and reverse genetic screens and chemical genetic screens. The C.  ...

Inducing Plasticity of Astrocytic Receptors by Manipulation of Neuronal Firing Rates

Close to two decades of research has established that astrocytes in situ and in vivo express numerous G protein-coupled receptors (GPCRs) that can be stimulated by neuronally-released transmitter. However, the ability of astrocytic receptors to exhibit plasticity in response to changes in neuronal activity has received little attention. Here we describe a model system that can be used to globally scale up or down astrocytic group I metabotropic glutamate receptors (mGluRs) in acute brain slices. Included are methods on how to prepare parasagittal hippocampal slices, construct chambers suitable for long-term slice incubation, bidirectionally manipulate neuronal action potential frequency, load astrocytes and astrocyte processes with fluorescent Ca2+ indicator, and measure changes in astrocytic Gq GPCR activity by recording spontaneous and evoked astrocyte Ca2+ events using confocal microscopy. In essence, a &#8220;calcium roadmap&#8221; is provided for how to measure plasticity of astrocytic Gq GPCRs. Applications of the technique for study of astrocytes are discussed. Having an understanding of how astrocytic receptor signaling is affected by changes in neuronal activity has important implications for both normal synaptic function as well as processes underlying neurological disorders and neurodegenerative disease.

Here we describe an adaptation of protocols used to induce homeostatic plasticity in neurons for the study of plasticity of astrocytic G protein-coupled receptors. Recently used to examine changes in astrocytic group I mGluRs in juvenile mice, the method can be applied to measure scaling of various astrocytic GPCRs, in tissue from adult mice in situ and in vivo, and to gain a better appreciation of the sensitivity of astrocytic receptors to changes in neuronal activity.

Close to two decades of research has established that astrocytes in situ and in vivo express numerous G protein-coupled receptors (GPCRs) that can be ...

Live Imaging of Nicotine Induced Calcium Signaling and Neurotransmitter Release Along Ventral Hippocampal Axons

Sustained enhancement of axonal signaling and increased neurotransmitter release by the activation of pre-synaptic nicotinic acetylcholine receptors (nAChRs) is an important mechanism for neuromodulation by acetylcholine (ACh). The difficulty with access to probing the signaling mechanisms within intact axons and at nerve terminals both in vitro and in vivo has limited progress in the study of the pre-synaptic components of synaptic plasticity. Here we introduce a gene-chimeric preparation of ventral hippocampal (vHipp)&#8211;accumbens (nAcc) circuit in vitro that allows direct live imaging to analyze both the pre- and post-synaptic components of transmission while selectively varying the genetic profile of the pre- vs post-synaptic neurons. We demonstrate that projections from vHipp microslices, as pre-synaptic axonal input, form multiple, reliable glutamatergic synapses with post-synaptic targets, the dispersed neurons from nAcc. The pre-synaptic localization of various subtypes of nAChRs are detected and the pre-synaptic nicotinic signaling mediated synaptic transmission are monitored by concurrent electrophysiological recording and live cell imaging. This preparation also provides an informative approach to study the pre- and post-synaptic mechanisms of glutamatergic synaptic plasticity in vitro.

We developed a gene-chimeric preparation of ventral hippocampal &#8211; accumbens circuit in vitro that allows direct live imaging to analyze presynaptic mechanisms of nicotinic acetylcholine receptors (nAChRs) mediated synaptic transmission. This preparation also provides an informative approach to study the pre- and post-synaptic mechanisms of synaptic plasticity.

Sustained enhancement of axonal signaling and increased neurotransmitter release by the activation of pre-synaptic nicotinic acetylcholine receptors ...

Utilizing Combined Methodologies to Define the Role of Plasma Membrane Delivery During Axon Branching and Neuronal Morphogenesis

During neural development, growing axons extend to multiple synaptic partners by elaborating axonal branches. Axon branching is promoted by extracellular guidance cues like netrin-1 and results in dramatic increases to the surface area of the axonal plasma membrane. Netrin-1-dependent axon branching likely involves temporal and spatial control of plasma membrane expansion, the components of which are supplied through exocytic vesicle fusion. These fusion events are preceded by formation of SNARE complexes, comprising a v-SNARE, such as VAMP2 (vesicle-associated membrane protein 2), and plasma membrane t-SNAREs, syntaxin-1 and SNAP25 (synaptosomal-associated protein 25). Detailed herein isa multi-pronged approach used to examine the role of SNARE mediated exocytosis in axon branching. The strength of the combined approach is data acquisition at a range of spatial and temporal resolutions, spanning from the dynamics of single vesicle fusion events in individual neurons to SNARE complex formation and axon branching in populations of cultured neurons. This protocol takes advantage of established biochemical approaches to assay levels of endogenous SNARE complexes and Total Internal Reflection Fluorescence (TIRF) microscopy of cortical neurons expressing VAMP2 tagged with a pH-sensitive GFP (VAMP2-pHlourin) to identify netrin-1 dependent changes in exocytic activity in individual neurons. To elucidate the timing of netrin-1-dependent branching, time-lapse differential interference contrast (DIC) microscopy of single neurons over the order of hours is utilized. Fixed cell immunofluorescence paired with botulinum neurotoxins that cleave SNARE machinery and block exocytosis demonstrates that netrin-1 dependent axon branching requires SNARE-mediated exocytic activity.

Light microscopy techniques coupled with biochemical assays elucidate the involvement of SNARE-mediated exocytosis in netrin-dependent axon branching. This combination of techniques permits identification of molecular mechanisms controlling axon branching and cell shape change.

During neural development, growing axons extend to multiple synaptic partners by elaborating axonal branches. Axon branching is promoted by extracellular ...

The Indirect Neuron-astrocyte Coculture Assay: An In Vitro Set-up for the Detailed Investigation of Neuron-glia Interactions

Proper neuronal development and function is the prerequisite of the developing and the adult brain. However, the mechanisms underlying the highly controlled formation and maintenance of complex neuronal networks are not completely understood thus far. The open questions concerning neurons in health and disease are diverse and reaching from understanding the basic development to investigating human related pathologies, e.g.,&#160;Alzheimer&#39;s disease and&#160;Schizophrenia. The most detailed analysis of neurons can be performed in vitro. However, neurons are demanding cells and need the additional support of astrocytes for their long-term survival. This cellular heterogeneity is in conflict with the aim to dissect the analysis of neurons and astrocytes. We present here a cell-culture assay that allows for the long-term cocultivation of pure primary neurons and astrocytes, which share the same chemically defined medium, while being physically separated. In this setup, the cultures survive for up to four weeks and the assay is suitable for a diversity of investigations concerning neuron-glia interaction.

The Indirect Neuron-astrocyte Coculture Assay: An In Vitro Set-up for the Detailed Investigation of Neuron-glia Interactions

This protocol describes the indirect neuron-astrocyte coculture for compartmentalized analysis of neuron-glia interactions.

Proper neuronal development and function is the prerequisite of the developing and the adult brain. However, the mechanisms underlying the highly ...

The Mouse Hindbrain As a Model for Studying Embryonic Neurogenesis

The mouse embryo forebrain is the most commonly employed system for studying mammalian neurogenesis during development. However, the highly folded forebrain neuroepithelium is not amenable to wholemount analysis to examine organ-wide neurogenesis patterns. Moreover, defining the mechanisms of forebrain neurogenesis is not necessarily predictive of neurogenesis in other parts of the brain; for example, due to the presence of forebrain-specific progenitor subtypes. The mouse hindbrain provides an alternative model for studying embryonic neurogenesis that is amenable to wholemount analysis, as well as tissue sections to observe the spatiotemporal distribution and behavior of neural progenitors. Moreover, it is easily dissected for other downstream applications, such as cell isolation or molecular biology analysis. As the mouse hindbrain can be readily analyzed in the vast number of cell lineage reporter and mutant mouse strains that have become available, it offers a powerful model for studying the cellular and molecular mechanisms of developmental neurogenesis in a mammalian organism. Here, we present a simple and quick method to use the mouse embryo hindbrain for analyzing mammalian neural progenitor cell (NPC) behavior in wholemount preparations and tissue sections.

This article demonstrates how the mouse embryonic hindbrain can be used as a model for studying developmental neurogenesis in both whole organ and tissue section preparations.

The mouse embryo forebrain is the most commonly employed system for studying mammalian neurogenesis during development. However, the highly folded ...

A Microbiomechanical System for Studying Varicosity Formation and Recovery in Central Neuron Axons

Axonal varicosities are enlarged structures along the shafts of axons with a high degree of heterogeneity. They are present not only in brains with neurodegenerative diseases or injuries, but also in the normal brain. Here, we describe a newly-established micromechanical system to rapidly, reliably, and reversibly induce axonal varicosities, allowing us to understand the mechanisms governing varicosity formation and heterogeneous protein composition. This system represents a novel means to evaluate the effects of compression and shear stress on different subcellular compartments of neurons, different from other in vitro systems that mainly focus on the effect of stretching. Importantly, owing to the unique features of our system, we recently made a novel discovery showing that the application of pressurized fluid can rapidly and reversibly induce axonal varicosities through the activation of a transient receptor potential channel. Our biomechanical system can be utilized conveniently in combination with drug perfusion, live cell imaging, calcium imaging, and patch clamp recording. Therefore, this method can be adopted for studying mechanosensitive ion channels, axonal transport regulation, axonal cytoskeleton dynamics, calcium signaling, and morphological changes related to traumatic brain injury.

This protocol describes a physiologically relevant, pressurized fluid approach for rapid and reversible induction of varicosities in neurons.

Axonal varicosities are enlarged structures along the shafts of axons with a high degree of heterogeneity. They are present not only in brains with ...