Name: assessment of neuronal viability using fluorescein diacetate-propidium iodide double staining in cerebellar granule neuron culture
Uploaded: 2017-05-10T14:00:00
Description: Watch this Scientific Journal Video about Assessment of Neuronal Viability Using Fluorescein Diacetate-Propidium Iodide Double Staining in Cerebellar Granule Neuron Culture at JoVE.com

This work was supported by grants from the Natural Science Foundation of Zhejiang Province (LY15H310007), the Applied Research Project on Nonprofit Technology of Zhejiang Province (2016C37110), the National Natural Science Foundation of China (U1503223, 81673407), the Ningbo International Science and Technology Cooperation Project (2014D10019), the Ningbo Municipal Innovation Team of Life Science and Health (2015C110026), the Guangdong Provincial International Cooperation Project of Science and Technology (No. 2013B051000038), the Shenzhen Basic Research Program (JCYJ20160331141459373), the Guangdong-Hong Kong Technology Cooperation Funding Scheme (GHP/012/16GD), the Research Grants Council of Hong Kong (15101014), Hong Kong Polytechnic University (G-YBGQ), and the K. C. Wong Magna Fund at Ningbo University.

All procedures followed the National Institutes of Health (NIH) Guide for the Care and Use of Laboratory Animals (NIH Publications No. 80-23, revised 1996) and were approved by the Institutional Animal Care and Use Committee (IACUC) at Ningbo University (SYXK-2008-0110).
1. Preparation of Solutions and Culture Media
Note: Reagents and stocks need to be prepared under sterile conditions. Sterilize by filtering using a filter with a pore size of 0.22 &#181;m.
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	<li>Yu, 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=Indirubin-3-oxime+prevents+H2O2-induced+neuronal+apoptosis+via+concurrently+inhibiting+GSK3beta+and+the+ERK+pathway.">Indirubin-3-oxime prevents H2O2-induced neuronal apoptosis via concurrently inhibiting GSK3beta and the ERK pathway.</a> Cell Mol Neurobiol. , (2016).</li><li>Cui, W., 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+anti-cancer+agent+SU4312+unexpectedly+protects+against+MPP(+)+-induced+neurotoxicity+via+selective+and+direct+inhibition+of+neuronal+NOS.">The anti-cancer agent SU4312 unexpectedly protects against MPP(+) -induced neurotoxicity via selective and direct inhibition of neuronal NOS.</a> Br J Pharmacol. 168 (5), 1201-1214 (2013).</li><li>Jebelli, J., Piers, T., Pocock, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+Depletion+of+Microglia+from+Cerebellar+Granule+Cell+Cultures+Using+L-leucine+Methyl+Ester.">Selective Depletion of Microglia from Cerebellar Granule Cell Cultures Using L-leucine Methyl Ester.</a> J Vis Exp. (101), e52983 (2015).</li><li>Labno, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Two way to count cells with ImageJ. , (2008).</li><li>Haag, D., 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=Nos2+Inactivation+promotes+the+development+of+medulloblastoma+in+Ptch1(+/-)+mice+by+deregulation+of+Gap43-dependent+granule+cell+precursor+migration.">Nos2 Inactivation promotes the development of medulloblastoma in Ptch1(+/-) mice by deregulation of Gap43-dependent granule cell precursor migration.</a> Plos Genet. 8 (3), e1002572 (2012).</li><li>Lee, H. Y., Greene, L. A., Mason, C. A., Manzini, M. C. <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+culture+of+post-natal+mouse+cerebellar+granule+neuron+progenitor+cells+and+neurons.">Isolation and culture of post-natal mouse cerebellar granule neuron progenitor cells and neurons.</a> J Vis Exp. (23), e990 (2009).</li><li>Messer, 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+maintenance+and+identification+of+mouse+cerebellar+granule+cells+in+monolayer+culture.">The maintenance and identification of mouse cerebellar granule cells in monolayer culture.</a> Brain Res. 130 (1), 1-12 (1977).</li><li>Li, W., 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+dimeric+acetylcholinesterase+inhibitor+bis7-tacrine,+but+not+donepezil,+prevents+glutamate-induced+neuronal+apoptosis+by+blocking+N-methyl-D-aspartate+receptors.">Novel dimeric acetylcholinesterase inhibitor bis7-tacrine, but not donepezil, prevents glutamate-induced neuronal apoptosis by blocking N-methyl-D-aspartate receptors.</a> J Biol Chem. 280 (18), 18179-18188 (2005).</li><li>Kaech, S., Banker, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Culturing+hippocampal+neurons.">Culturing hippocampal neurons.</a> Nat Protoc. 1 (5), 2406-2415 (2006).</li><li>Cheung, G., Cousin, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+analysis+of+synaptic+vesicle+pool+replenishment+in+cultured+cerebellar+granule+neurons+using+FM+Dyes.">Quantitative analysis of synaptic vesicle pool replenishment in cultured cerebellar granule neurons using FM Dyes.</a> J Vis Exp. (57), e3143 (2011).</li><li>Atlante, 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=Genistein+and+daidzein+prevent+low+potassium-dependent+apoptosis+of+cerebellar+granule+cells.">Genistein and daidzein prevent low potassium-dependent apoptosis of cerebellar granule cells.</a> Biochem Pharmacol. 79 (5), 758-767 (2010).</li><li>Silva, R., Rodrigues, C., Brites, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rat+cultured+neuronal+and+glial+cells+respond+differently+to+toxicity+of+unconjugated+bilirubin.">Rat cultured neuronal and glial cells respond differently to toxicity of unconjugated bilirubin.</a> Pediatr Res. 51 (4), 535-541 (2002).</li><li>Jekabsons, M. B., Nicholls, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioenergetic+analysis+of+cerebellar+granule+neurons+undergoing+apoptosis+by+potassium/serum+deprivation.">Bioenergetic analysis of cerebellar granule neurons undergoing apoptosis by potassium/serum deprivation.</a> Cell Death Differ. 13 (9), 1595-1610 (2006).</li><li>Garner, D. L., Johnson, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Viability+Assessment+of+Mammalian+Sperm+Using+Sybr-14+and+Propidium+Iodide.">Viability Assessment of Mammalian Sperm Using Sybr-14 and Propidium Iodide.</a> Biol Reprod. 53 (2), 276-284 (1995).</li></ol>

This protocol was modified from procedures that have been described previously6,7. Researchers have spent time trying to reduce non-neuronal cell growth by improving the conditions when culturing primary neurons in vitro8. However, even with improved culture conditions, some glial cells remain. Moreover, non-neuronal cells are necessary in primary neuronal cultures because they help with neuronal growth and maturation<sup class="x...

Colorimetric cytotoxicity assays, such as the 3- (4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay, are commonly used to measure cell viability in vitro. Primary cultured Cerebellar Granule Neurons (CGNs) from rats are sensitive to various neurotoxins, including 1-methyl-4-phenylpyridinium ion, hydrogen peroxide, and glutamate1,2. Therefore, CGN cultures can be used as an in vitro model in the field of neuroscience. CGN cultures may contain a variety of cells, including neurons and glial cells, which can account for about 1% of the total cells in the CGN culture. However, glial cells respond differently to neurotoxins as compared to neurons, leading to a bias in the neuronal viability measured by colorimetric assays3.
In viable cells, Fluorescein diacetate (FDA) can be converted into fluorescein by esterase. Propidium Iodide (PI) can interact with the DNA after penetrating dead cells and can be used to indicate apoptosis within the culture. Therefore, FDA-PI double staining can simultaneously evaluate viable cells and dead cells, suggesting that the cell viability can be measured more accurately by combining both colorimetric methods. Moreover, by adding Hoechst, a blue fluorescent stain for nuclei, the accuracy of cell viability could be further improved. The protocol presented here describes FDA-PI double staining and FDA-PI-Hoechst triple staining, which can be used to accurately analyze neuronal viability in primary cultured CGNs.
This protocol takes advantage of visualizing and distinguishing CGNs and glial cells by their different sizes and shapes. After staining, the numbers of viable neurons and dead neurons are counted from representative images taken by fluorescent microscopy. The large-size glial cells are excluded by the comparison of typical CGNs taken under fluorescent mode with those taken under phase contrast mode. A similar strategy can be performed to measure neuronal viability in mixed cell cultures containing neurons and glial cells, such as primary cortical cultures and hippocampal cultures.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Poly-L-lysine</td>
			<td>Sigma</td>
			<td>P2636</td>
			<td></td>
		</tr>
		<tr>
			<td>D-glucose</td>
			<td>Sigma</td>
			<td>G8270</td>
			<td></td>
		</tr>
		<tr>
			<td>Cytosine &#946;-D-Arabinofuranoside</td>
			<td>Sigma</td>
			<td>C1768</td>
			<td></td>
		</tr>
		<tr>
			<td>&#160;Fetal bovine serum</td>
			<td>Gibco</td>
			<td>10099141&#160;</td>
			<td>high quality FBS is essential for culture</td>
		</tr>
		<tr>
			<td>100&#215; glutamine</td>
			<td>Gibco</td>
			<td>25030081</td>
			<td></td>
		</tr>
		<tr>
			<td>100&#215; anti-biotic</td>
			<td>Gibco</td>
			<td>15240062</td>
			<td></td>
		</tr>
		<tr>
			<td>BME medium</td>
			<td>Gibco</td>
			<td>21010046&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>Fluorescein diacetate</td>
			<td>Sigma</td>
			<td>F7378</td>
			<td></td>
		</tr>
		<tr>
			<td>Propidium iodide</td>
			<td>Sigma</td>
			<td>P4170</td>
			<td></td>
		</tr>
		<tr>
			<td>Hoechst 33342</td>
			<td>Yesen</td>
			<td>40731ES10</td>
			<td></td>
		</tr>
		<tr>
			<td>rabbit Anti-GAP43 antibody</td>
			<td>Abcam</td>
			<td>ab75810</td>
			<td></td>
		</tr>
		<tr>
			<td>mouse Anti-GFAP antibody</td>
			<td>Cellsignaling</td>
			<td>3670</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine serum albumin</td>
			<td>Sangon Biotech</td>
			<td>A602440</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin&#160;</td>
			<td>Sigma</td>
			<td>T4665</td>
			<td></td>
		</tr>
		<tr>
			<td>DNAse&#160;</td>
			<td>Sigma</td>
			<td>D5025</td>
			<td></td>
		</tr>
		<tr>
			<td>Soybean trypsin inhibitor</td>
			<td>Sigma</td>
			<td>T9003</td>
			<td></td>
		</tr>
		<tr>
			<td>Pasteur pipette</td>
			<td>Volac</td>
			<td>Z310727</td>
			<td>burn&#160; the tip round before use</td>
		</tr>
		<tr>
			<td>12-well cell culture plates</td>
			<td>TPP</td>
			<td>Z707783</td>
			<td></td>
		</tr>
		<tr>
			<td>6-well cell culture plates</td>
			<td>TPP</td>
			<td>Z707759</td>
			<td>high quality cell culture plate&#160; is essential for culture</td>
		</tr>
		<tr>
			<td>Filter</td>
			<td>Millipore</td>
			<td>SLGP033RB</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipet 5 ml</td>
			<td>Excell Bio</td>
			<td>CS017-0003</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipet 10 ml</td>
			<td>Excell Bio</td>
			<td>CS017-0004</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissect microscope</td>
			<td>Shanghai Caikang</td>
			<td>XTL2400</td>
			<td></td>
		</tr>
		<tr>
			<td>CO2 Incubator</td>
			<td>Thermo Scientific&#160;</td>
			<td>311</td>
			<td></td>
		</tr>
		<tr>
			<td>Fluorescence microscope&#160;</td>
			<td>Nikon</td>
			<td>TI-S</td>
			<td></td>
		</tr>
		<tr>
			<td>Fluorescence filter and emmision cubes</td>
			<td>Nikon</td>
			<td>B-2A, G-2A, UV-2A</td>
			<td></td>
		</tr>
		<tr>
			<td>Photo software</td>
			<td>Nikon</td>
			<td>NIS-Elements</td>
			<td></td>
		</tr>
		<tr>
			<td>Graphics editor softeware</td>
			<td>Adobe</td>
			<td>Photoshop CS</td>
			<td></td>
		</tr>
		<tr>
			<td>Image process softeware</td>
			<td>NIH</td>
			<td>ImageJ</td>
			<td></td>
		</tr>
	</tbody>
</table>

assessment of neuronal viability using fluorescein diacetate-propidium iodide double staining in cerebellar granule neuron culture

Primary cultured Cerebellar Granule Neurons (CGNs) have been widely used as an in vitro model in neuroscience and neuropharmacology research. However, the co-existence of glial cells and neurons in CGN culture might lead to biases in the accurate assessment of neuronal viability. Fluorescein diacetate (FDA) and Propidium Iodide (PI) double staining has been used to measure cell viability by simultaneously evaluating the viable and dead cells. We used FDA-PI double staining to improve the sensitivities of the colorimetric assays and to evaluate neuronal viability in CGNs. Furthermore, we added blue fluorescent DNA stains (e.g., Hoechst) to improve the accuracy. This protocol describes how to improve the accuracy of assessment of neuronal viability by using these methods in CGN culture. Using this protocol, the number of glial cells can be excluded by using fluorescence microscopy. A similar strategy can be applied to distinguish the unwanted glial cells from neurons in various mixed cell cultures, such as primary cortical culture and hippocampal culture.

The dual immunostaining of GAP43 (red) and GFAP (green) was used to analyze the shape of neurons and glial cells, respectively2,5. Both neurons and glial cells are present in CGN culture. The GFAP-positive glial cells are large and irregular in shape, as indicated by the arrows in the images (Figure 1). Traditional assays for cell vitality cannot distinguish glial cells from neurons when used to measure neuronal v...

Watch this Scientific Journal Video about Assessment of Neuronal Viability Using Fluorescein Diacetate-Propidium Iodide Double Staining in Cerebellar Granule Neuron Culture at JoVE.com

Assessment of Neuronal Viability Using Fluorescein Diacetate-Propidium Iodide Double Staining in Cerebellar Granule Neuron Culture

This protocol describes how to accurately measure neuronal viability using Fluorescein diacetate (FDA) and Propidium Iodide (PI) double staining in cultured cerebellar granule neurons, a primary neuronal culture used as an in vitro model in neuroscience and neuropharmacology research.

Primary cultured Cerebellar Granule Neurons (CGNs) have been widely used as an in vitro model in neuroscience and neuropharmacology research. However, the ...

The overall goal of this procedure is to accurately measure cell viability in a cerebellar granule neuron culture. This method can help to answer key questions in the field of neuroscience and neuropharmacology. The main advantage of this technique is that we can distinguish unwanted glial cells from neurons in MISTA cell cultures.Demonstrating the procedures will be Lin Jiajia, Wang Jialing, Xu Dilin, three undergraduate students from my lab. Begin dissecting the heads of eight-day-old rat pups by first inserting scissors into the foramen magnum and cutting the two sides of the skull from the ears to the eyes. Then, use forceps to lift the skull.Use forceps to isolate the cerebellum, and place it into a 35-millimeter dish containing dissection solution. Transfer the plate to the stage of the dissecting microscope and use two pairs of forceps to remove the meninges and blood vessels. Use a blade to chop the tissues, and then transfer the tissue into a centrifuge tube containing 30 milliliters of dissection solution.Centrifuge for five minutes at room temperature at 1, 500 x g. Following the centrifugalization, aspirate the supernatant and save the pellet. Next, add Trypsin solution to the pellet and resuspend by shaking gently.Then place the tube in a 37 degree celsius water bath for 15 minutes. After 15 minutes, add a solution of DNase One, soybean Trypsin inhibitor, and magnesium sulfate, and shake. Then centrifuge for five minutes at room temperature at 1, 500 x g.After aspirating the supernatant, resuspend the pellet in a less dilute DNase One, soybean Trypsin inhibitor, and magnesium sulfate solution. Next, prepare two 15-milliliter tubes. Place half of the cells in each tube, and pipette both up and down 60 to 70 times using a cotton-plugged Pasteur pipette to homogenize the cells.After homogenization, add three milliliters of magnesium sulfate and calcium chloride solution to each 15-milliliter tube. Allow the tubes to sit at room temperature for 10 minutes. Once the time has elapsed, carefully remove the supernatant with a cotton-plugged Pasteur pipette and transfer to new 15-milliliter tubes.Centrifuge for five minutes at room temperature and 1, 500 x g. Add culture medium to the pellet to dilute to a cell density of around 1.5 x 10 to the sixth cells per milliliter. Pipette the cells into a 6-well plate, and culture in the incubator at 37 degrees celsius and 5%carbon dioxide.After 24 hours, add AraC stock solution to a final concentration of one millimolar to inhibit the growth of the glial cells before returning the plates to the incubator. Then, on day seven, add 50 microliters to D-glucose stock solution to a final concentration of one millimolar. Begin the staining by mixing fluorescein diacetate to a final concentration of 10 micrograms per milliliter, and propidium iodide to a final concentration of 50 micrograms per milliliter and 10 milliliters of PBS.Mix the FDA/PI solution by vortexing and place on ice. Place the culture plate on ice. Carefully aspirate the culture medium without touching the cells with the pipette tip, then slowly add cold PBS.Aspirate the PBS, then add cold FDA/PI, or FDA/PI Hoechst working solution. Put the plate on ice for five minutes. Next, after aspirating the FDA/PI, or FDA/PI/Hoechst working solution, add cold PBS to each well.Make sure that the fluorescent microscope is set up correctly. Detect the fluorescent emissions for FDA, PI, and Hoechst at 520, 620, and 460 nanometers, respectively, using an exposure time between 100 and 300 milliseconds and an analog gain of 2.8 x. After collecting fluorescence images, take an image under normal light using the phase contrast mode.For FDA/PI double staining, overlay the images of the cells by dragging the FDA positive layer on top of the PI positive layer in graphics editing software. Adjust the opacity of the FDA positive layer by entering 50%in the Opacity field of the Layers panel. Merge two layers by opening the Layer menu and clicking on the Merge Visible button.Set the contrast of the overlay images by entering 50 in the Contrast field under Image, Adjustments, Brightness/Contrast. Check that there are no FDA and PI double positive cells in the overlay images. For FDA/PI/Hoechst triple staining, overlay the images of the cells by again dragging the FDA positive layer on the PI positive layer, adjusting the opacity of the FDA positive layer and merging the images as before.Then drag the Hoechst positive layer on the merged layer. Adjust the opacity of the Hoechst positive layer by entering 50%in the Opacity field of the Layers panel, and merge the two layers by opening the Layer menu and clicking on the Merge Visible button. Visually distinguish large, irregular glial cells from cerebellar granular neurons by comparing the images taken under fluorescent mode with those taken under phase contrast mode.The following images show that both small neurons and large, irregular glial cells are present in CGN culture. This image shows GAP-43 amino staining of a CGN culture at eight days in vitro. The blue arrows indicate neurons.Here, GFAP amino staining of glial cells is shown. The white arrow indicates a glial cell. This phase contrast image shows the morphology of the cells.FDA/PI hook staining which can distinguish glial cells from neurons is advantageous for the accurate evaluation of neuronal viability in CGN culture. This is a merged image of triple-stained cells grown in normal growth medium. The arrow shows a typical glial cell.Here, a similar culture has been treated with medium containing low potassium, and the arrow again indicates a typical glial cell. Also, note the appearance of red propidium iodide staining. Once mastered, this technique can be done in two hours if it is performed properly.A similar strategy can be applied to other mixed cell cultures, such as primary cortical cultures, and primary hippocampal cultures to accurately analyze neuronal viability.

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Research

JoVE Journal

Neuroscience

Quantitative Analysis of Synaptic Vesicle Pool Replenishment in Cultured Cerebellar Granule Neurons using FM Dyes

After neurotransmitter release in central nerve terminals, SVs are rapidly retrieved by endocytosis. Retrieved SVs are then refilled with neurotransmitter and rejoin the recycling pool, defined as SVs that are available for exocytosis1,2. The recycling pool can generally be subdivided into two distinct pools - the readily releasable pool (RRP) and the reserve pool (RP). As their names imply, the RRP consists of SVs that are immediately available for fusion while RP SVs are released only during intense stimulation1,2. It is important to have a reliable assay that reports the differential replenishment of these SV pools in order to understand 1) how SVs traffic after different modes of endocytosis (such as clathrin-dependent endocytosis and activity-dependent bulk endocytosis) and 2) the mechanisms controlling the mobilisation of both the RRP and RP in response to different stimuli.
FM dyes are routinely employed to quantitatively report SV turnover in central nerve terminals3-8. They have a hydrophobic hydrocarbon tail that allows reversible partitioning in the lipid bilayer, and a hydrophilic head group that blocks passage across membranes. The dyes have little fluorescence in aqueous solution, but their quantum yield increases dramatically when partitioned in membrane9. Thus FM dyes are ideal fluorescent probes for tracking actively recycling SVs. The standard protocol for use of FM dye is as follows. First they are applied to neurons and are taken up during endocytosis (Figure 1). After non-internalised dye is washed away from the plasma membrane, recycled SVs redistribute within the recycling pool. These SVs are then depleted using unloading stimuli (Figure 1). Since FM dye labelling of SVs is quantal10, the resulting fluorescence drop is proportional to the amount of vesicles released. Thus, the recycling and fusion of SVs generated from the previous round of endocytosis can be reliably quantified.
Here, we present a protocol that has been modified to obtain two additional elements of information. Firstly, sequential unloading stimuli are used to differentially unload the RRP and the RP, to allow quantification of the replenishment of specific SV pools. Secondly, each nerve terminal undergoes the protocol twice. Thus, the response of the same nerve terminal at S1 can be compared against the presence of a test substance at phase S2 (Figure 2), providing an internal control. This is important, since the extent of SV recycling across different nerve terminals is highly variable11.
Any adherent primary neuronal cultures may be used for this protocol, however the plating density, solutions and stimulation conditions are optimised for cerebellar granule neurons (CGNs)12,13.

A live fluorescence imaging technique to quantify the replenishment and mobilisation of specific synaptic vesicle (SV) pools in central nerve terminals is described. Two rounds of SV recycling are monitored in the same nerve terminals providing an internal control.

After neurotransmitter release in central nerve terminals, SVs are rapidly retrieved by endocytosis.  Retrieved SVs are then refilled with ...

Imaging Analysis of Neuron to Glia Interaction in Microfluidic Culture Platform (MCP)-based Neuronal Axon and Glia Co-culture System

Proper neuron to glia interaction is critical to physiological function of the central nervous system (CNS). This bidirectional communication is sophisticatedly mediated by specific signaling pathways between neuron and glia1,2 . Identification and characterization of these signaling pathways is essential to the understanding of how neuron to glia interaction shapes CNS physiology. Previously, neuron and glia mixed cultures have been widely utilized for testing and characterizing signaling pathways between neuron and glia. What we have learned from these preparations and other in vivo tools, however, has suggested that mutual signaling between neuron and glia often occurred in specific compartments within neurons (i.e., axon, dendrite, or soma)3. This makes it important to develop a new culture system that allows separation of neuronal compartments and specifically examines the interaction between glia and neuronal axons/dendrites. In addition, the conventional mixed culture system is not capable of differentiating the soluble factors and direct membrane contact signals between neuron and glia. Furthermore, the large quantity of neurons and glial cells in the conventional co-culture system lacks the resolution necessary to observe the interaction between a single axon and a glial cell.
	In this study, we describe a novel axon and glia co-culture system with the use of a microfluidic culture platform (MCP). In this co-culture system, neurons and glial cells are cultured in two separate chambers that are connected through multiple central channels. In this microfluidic culture platform, only neuronal processes (especially axons) can enter the glial side through the central channels. In combination with powerful fluorescent protein labeling, this system allows direct examination of signaling pathways between axonal/dendritic and glial interactions, such as axon-mediated transcriptional regulation in glia, glia-mediated receptor trafficking in neuronal terminals, and glia-mediated axon growth. The narrow diameter of the chamber also significantly prohibits the flow of the neuron-enriched medium into the glial chamber, facilitating probing of the direct membrane-protein interaction between axons/dendrites and glial surfaces.

Imaging Analysis of Neuron to Glia Interaction in Microfluidic Culture Platform MCP-based Neuronal Axon and Glia Co-culture System

This study describes the procedures of setting up a novel neuronal axon and (astro)glia co-culture platform. In this co-culture system, manipulation of direct interaction between a single axon (and single glial cell) becomes feasible, allowing mechanistic analysis of the mutual neuron to glial signaling.

Proper  neuron to glia interaction is critical to physiological function of the central  nervous system (CNS). This bidirectional communication is ...

Fast Micro-iontophoresis of Glutamate and GABA: A Useful Tool to Investigate Synaptic Integration

One of the fundamental interests in neuroscience is to understand the integration of excitatory and inhibitory inputs along the very complex structure of the dendritic tree, which eventually leads to neuronal output of action potentials at the axon. The influence of diverse spatial and temporal parameters of specific synaptic input on neuronal output is currently under investigation, e.g. the distance-dependent attenuation of dendritic inputs, the location-dependent interaction of spatially segregated inputs, the influence of GABAergig inhibition on excitatory integration, linear and non-linear integration modes, and many more.
With fast micro-iontophoresis of glutamate and GABA it is possible to precisely investigate the spatial and temporal integration of glutamatergic excitation and GABAergic inhibition. Critical technical requirements are either a triggered fluorescent lamp, light-emitting diode (LED), or a two-photon scanning microscope to visualize dendritic branches without introducing significant photo-damage of the tissue. Furthermore, it is very important to have a micro-iontophoresis amplifier that allows for fast capacitance compensation of high resistance pipettes. Another crucial point is that no transmitter is involuntarily released by the pipette during the experiment.
Once established, this technique will give reliable and reproducible signals with a high neurotransmitter and location specificity. Compared to glutamate and GABA uncaging, fast iontophoresis allows using both transmitters at the same time but at very distant locations without limitation to the field of view. There are also advantages compared to focal electrical stimulation of axons: with micro-iontophoresis the location of the input site is definitely known and it is sure that only the neurotransmitter of interest is released. However it has to be considered that with micro-iontophoresis only the postsynapse is activated and presynaptic aspects of neurotransmitter release are not resolved. In this article we demonstrate how to set up micro-iontophoresis in brain slice experiments.

In this article we introduce fast micro-iontophoresis of neurotransmitters as a technique to investigate integration of postsynaptic signals with high spatial and temporal precision.

One of the fundamental interests in neuroscience is to understand the integration of excitatory and inhibitory inputs along the very complex structure of ...

Genetic Manipulation of Cerebellar Granule Neurons In Vitro and In Vivo to Study Neuronal Morphology and Migration

Developmental events in the brain including neuronal morphogenesis and migration are highly orchestrated processes. In vitro and in vivo analyses allow for an in-depth characterization to identify pathways involved in these events. Cerebellar granule neurons (CGNs) that are derived from the developing cerebellum are an ideal model system that allows for morphological analyses. Here, we describe a method of how to genetically manipulate CGNs and how to study axono- and dendritogenesis of individual neurons. With this method the effects of RNA interference, overexpression or small molecules can be compared to control neurons. In addition, the rodent cerebellar cortex is an easily accessible in vivo system owing to its predominant postnatal development. We also present an in vivo electroporation technique to genetically manipulate the developing cerebella and describe subsequent cerebellar analyses to assess neuronal morphology and migration.

Genetic Manipulation of Cerebellar Granule Neurons In Vitro and In Vivo to Study Neuronal Morphology and Migration

Neuronal morphogenesis and migration are crucial events underlying proper brain development. Here, we describe methods to genetically manipulate cultured cerebellar granule neurons and the developing cerebellum for the assessment of morphology and migratory characteristics of neurons.

Developmental events in the brain including neuronal morphogenesis and migration are highly orchestrated processes. In vitro and in vivo analyses allow ...

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

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

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

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

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

Selective Depletion of Microglia from Cerebellar Granule Cell Cultures Using L-leucine Methyl Ester

Microglia, the resident immunocompetent cells of the CNS, play multifaceted roles in modulating and controlling neuronal function, as well as mediating innate immunity. Primary rodent cell culture models have greatly advanced our understanding of neuronal-glial interactions, but only recently have methods to specifically eliminate microglia from mixed cultures been utilized. One such technique &#8211; described here &#8211; is the use of L-leucine methyl ester, a lysomotropic agent that is internalized by macrophages and microglia, wherein it causes lysosomal disruption and subsequent apoptosis13,14. Experiments using L-leucine methyl ester have the power to identify the contribution of microglia to the surrounding cellular environment under diverse culture conditions. Using a protocol optimized in our laboratory, we describe how to eliminate microglia from P5 rodent cerebellar granule cell culture. This approach allows one to assess the relative impact of microglia on experimental data, as well as determine whether microglia are playing a neuroprotective or neurotoxic role in culture models of neurological conditions, such as stroke, Alzheimer&#8217;s or Parkinson&#8217;s disease.

Microglia can influence neurons and other glia in culture by various non-cell autonomous mechanisms. Here, we present a protocol to selectively deplete microglia from primary neuronal cultures. This method has the potential to elucidate the role of microglial-neuronal interactions, with implications for neurodegenerative conditions where neuroinflammation is a hallmark feature.

Microglia, the resident immunocompetent cells of the CNS, play multifaceted roles in modulating and controlling neuronal function, as well as mediating ...

Low-Density Primary Hippocampal Neuron Culture

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

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

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

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 ...

Assessment of Long-term Depression Induction in Adult Cerebellar Slices

Synaptic plasticity provides a mechanism for learning and memory. For cerebellar motor learning, long-term depression (LTD) of synaptic transmissions from parallel fibers (PF) to Purkinje cells (PC) is considered the basis for motor learning, and deficiencies of both LTD and motor learning are observed in various gene-manipulated animals. Common motor learning sets, such as adaptation of the optokinetic reflex (OKR), the vestibular-ocular reflex (VOR), and rotarod test were used for evaluation of motor learning ability. However, results obtained from the GluA2-carboxy terminus modified knock-in mice demonstrated normal adaptation of the VOR and the OKR, despite lacking PF-LTD. In that report, induction of LTD was only attempted using one type of stimulation protocol at room temperature. Thus, conditions to induce cerebellar LTD were explored in the same knock-in mutants using various protocols at near physiological temperature. Finally, we found stimulation protocols, by which LTD could be induced in these gene-manipulated mice. In this study, a set of protocols are proposed to evaluate LTD-induction, which will more accurately allow examination of the causal relationship between LTD and motor learning. In conclusion, experimental conditions are crucial when evaluating LTD in gene-manipulated mice.

In some gene-manipulated animals, using a single protocol may fail to induce LTD in cerebellar Purkinje cells, and there may be a discrepancy between LTD and motor learning. Multiple protocols are necessary to assess LTD-induction in gene-manipulated animals. Standard protocols are shown.

Synaptic plasticity provides a mechanism for learning and memory. For cerebellar motor learning, long-term depression (LTD) of synaptic transmissions from ...

Presynapse Formation Assay Using Presynapse Organizer Beads and &ldquo;Neuron Ball&rdquo; Culture

During neuronal development, synapse formation is an important step to establish neural circuits. To form synapses, synaptic proteins must be supplied in appropriate order by transport from cell bodies and/or local translation in immature synapses. However, it is not fully understood how synaptic proteins accumulate in synapses in proper order. Here, we present a novel method to analyze presynaptic formation by using the combination of neuron ball culture with beads to induce presynapse formation. Neuron balls that is neuronal cell aggregates provide axonal sheets far from cell bodies and dendrites, so that weak fluorescent signals of presynapses can be detected by avoiding overwhelming signals of cell bodies. As beads to trigger presynapse formation, we use beads conjugated with leucine-rich repeat transmembrane neuronal 2 (LRRTM2), an excitatory presynaptic organizer. Using this method, we demonstrated that vesicular glutamate transporter 1 (vGlut1), a synaptic vesicle protein, accumulated in presynapses faster than Munc18-1, an active zone protein. Munc18-1 accumulated translation-dependently in presynapse even after removing cell bodies. This finding indicates the Munc18-1 accumulation by local translation in axons, not transport from cell bodies. In conclusion, this method is suitable to analyze accumulation of synaptic proteins in presynapses and source of synaptic proteins. As neuron ball culture is simple and it is not necessary to use special apparatus, this method could be applicable to other experimental platforms.

Presynapse formation is a dynamic process including accumulation of synaptic proteins in proper order. In this method, presynapse formation is triggered by beads conjugated with a presynapse organizer protein on axonal sheets of &#8220;neuron ball&#8221; culture, so that accumulation of synaptic proteins is easy to be analyzed during presynapse formation.

During neuronal development, synapse formation is an important step to establish neural circuits. To form synapses, synaptic proteins must be supplied in ...