XL was supported in part by the National Key R&#38;D Program of China (2017YFE0196600), and the National Natural Science Foundation of China (Grant Nos. 31771395, 31571518). Q.S. was supported by the National Key Research and Development Program of China (2017YFC1001703) and the Key Research and Development Program of Zhejiang Province (2017C03009). W.X. was supported by the Natural Science Foundation of Zhejiang province (LY18H020002) and Science Technology Department of Zhejiang Province (2017C37057).

All the animal procedures have been approved by the Animal Ethics Committee of Zhejiang University.
1. The Culture of Adult Neural Stem Cells and Neurons
<ol>
	<li>Isolate adult neural stem cells from the forebrain of an adult (8-10 week old) C57/BL6 male mouse as described previously31,32.</li>
	<li>Culture adult neural stem cells in DMEM/F-12 medium containing 20 ng/mL FGF-2, 20 ng/mL EGF, 2% B27 supplement, 1% antibiotic-antimycotic, and 2 mM L-Glutamine in a 5% CO2 incubator at 37 &#176;C. Induce the differentiation of adult neural stem cells with 1 &#181;M retinoic acid and 5 &#181;M forskolin for 48 h as described previously31,32.</li>
	<li>Isolate neurons from the embryonic day 17 (E17) hippocampi of the mouse and culture with neurobasal medium containing of 0.25% L-Glutamine, 0.125% GlutaMax and 2% B27 supplement in a 5% CO2 incubator at 37 &#176;C as previously described33.</li>
</ol>
2. Transcardial Perfusion of the Mouse
<ol>
	<li>Prepare 10% chloral hydrate, 4% paraformaldehyde (PFA) and phosphate buffered saline (PBS) one day before the experiment, and store at 4 &#176;C.</li>
	<li>Anesthetize an adult male or female C57 BL/6J mouse with 10% chloral hydrate (50 mg/kg, i.p.), and ensure that the animal is deeply anesthetized by checking the body reaction. Fix each limb with sticky tape on a plastic board (in a face-up position).</li>
	<li>Cut the skin and then the muscle with surgery scissors. Open the thoracic cavity with a surgical scissor. Expose the heart and cut off a little part of the right atrium with a fine surgical scissor.</li>
	<li>Perfuse the mouse with a 10 mL disposable sterilized syringe from the left ventricle with cold PBS (around 30 mL per adult mouse).</li>
	<li>Perfuse the mouse with 4% PFA (around 30 mL in 10 min per adult mice) until it is stiff.</li>
	<li>Open the skull of the mouse with bone forceps. Remove the brain and put into 5 mL of 4% PFA in a 15 mL centrifuge tube for post-fixation at 4 &#176;C. 
	NOTE: Clean the surgical area after surgery has finished.</li>
	<li>At least 24 h later, transfer the brain samples into a 30% sucrose solution for complete dehydration at 4 &#176;C.</li>
</ol>
3. Brain Sectioning
<ol>
	<li>Embed the brain samples in optimal cutting temperature compound (OCT) in a small container, and cool down at -20 &#176;C for at least 1 h.</li>
	<li>Section brain samples at a thickness of 20-40 &#956;m with a cryostat microtome.</li>
	<li>Collect sections into PBS and store at 4 &#176;C.</li>
</ol>
4. Immunofluorescence Staining
<ol>
	<li>Pick up the sections with the targeted brain regions and put them into a 24-well plate with PBS. For cultured cells on a coverslip, go directly to step 4.2.</li>
	<li>Wash with PBS on the shaker at room temperature for 10 min. Repeat this twice more.</li>
	<li>Remove PBS, and treat with preheated 1 M HCl for 30 min at 37 &#176;C. 
	NOTE: Prepare 1 M HCl by adding 1 mL of hydrochloric acid (36-38%) into 10 mL of water in a chemical hood. Preheat 1 M HCl in the incubator at 37 &#176;C.</li>
	<li>Wash the samples with PBS for 5 min. Repeat this twice more.</li>
	<li>Block samples with PBS containing 3% normal goat serum and 0.1% Triton X-100 for 1 h on the shaker at room temperature.</li>
	<li>Incubate sections with specific primary antibodies overnight at 4 &#176;C on the shaker. 
	NOTE: Use the following primary antibodies: polyclonal rabbit antibodies anti-5-hydroxymethylcytosine (1:5,000), mouse monoclonal antibody anti-NeuN (1:500).</li>
	<li>Take out the samples, and further incubate at room temperature for 1 h.</li>
	<li>Wash the samples with PBS for 10 min. Repeat this twice more.</li>
	<li>Incubate with secondary antibodies corresponding to the primary antibodies at room temperature for 1 h on the shaker. Cover the plate with aluminum. 
	NOTE: Use the following secondary antibodies: Alexa Fluor 488 goat anti-rabbit IgG (1:500), Alexa Fluor 568 goat anti-mouse IgG (1:500). Counterstain nuclei with 4&#8242;-6-diamidino-2-phenylindole (DAPI).</li>
	<li>Wash the samples with PBS for 10 min on the shaker. Repeat this twice more.</li>
	<li>Mount brain sections onto the slides, add proper amount of antifade mounting medium (around 100-150 &#956;L), and cover with premium cover glass. Seal with nail polish.</li>
	<li>Take images with a regular or confocal fluorescence microscope.</li>
</ol>
5. Genomic DNA Isolation
<ol>
	<li>Euthanize an adult C57 BL/6J mouse (male or female) by cervical dislocation and remove the brain.</li>
	<li>Dissect the hippocampus, cortex and cerebellum tissues on an ice-cooled dish. Grind tissues with a tissue grinder in 1 mL of DNA lysis buffer and transfer into clean microcentrifuge tube. Add 250 &#956;g of proteinase K per 600 &#956;L of lysis buffer. For cell pellets, directly add lysis buffer, proteinase K, and mix thoroughly. 
	NOTE: Prepare DNA lysis buffer: 5 mM EDTA, 0.2% SDS, 200 mM NaCl in 100 mM Tris-HCl, pH 8.5. Wash and autoclave the tissue grinder before the experiment.</li>
	<li>The second day, add about 50 &#956;g of RNase A per sample for at least 12 h at 37 &#176;C.</li>
	<li>Add an equal volume of phenol:chloroform:isoamyl alcohol (25:24:1) and mix completely.</li>
	<li>Centrifuge at 20,817 x g for 15 min, and remove the supernatant into a new microcentrifuge tube.</li>
	<li>Add 600 &#956;L of chloroform to the supernatant to precipitate DNA, and mix thoroughly.</li>
	<li>Centrifuge at 20,817 x g for 15 min, and remove the supernatant into another new tube.</li>
	<li>Add 500 &#956;L of isopropanol to the supernatant, and mix thoroughly.</li>
	<li>Centrifuge at 20,817 x g for 15 min, and remove the supernatant completely.</li>
	<li>Wash the precipitation with 1 mL of 70% ethanol, centrifuge at 20,817 x g for 1 min, and remove the supernatant completely. Repeat once.</li>
	<li>Dry the DNA pellet completely.</li>
	<li>Dissolve DNA pellet with Tris-HCl buffer (pH 8.5) to the proper concentration.</li>
</ol>
6. DNA Dot Blot
<ol>
	<li>Prepare the solutions: 2 M NaOH, Tris-HCl buffer (pH 8.5), 6x saline sodium citrate (SSC).</li>
	<li>Make the sample mixture as Table 1.</li>
	<li>Denature DNA samples at 100 &#176;C for 10 min, and cool down on ice.</li>
	<li>Cut the proper size of nylon membrane (e.g., Hybond-N+) and rinse with 6x SSC.</li>
	<li>Put the membrane on dot-blot apparatus and connect to the vacuum pump. Spot 6 &#956;L of mixture per dot onto the membrane.</li>
	<li>Hybridize for 30 min at 80 &#176;C, and block the sample membrane with fat-free milk in Tris-buffered saline (TBS) for 1 h.</li>
	<li>Incubate with primary antibody at 4 &#176;C overnight. 
	NOTE: the following primary antibody: polyclonal rabbit anti-5-hydroxymethylcytosine (1:5,000).</li>
	<li>On the second day, incubate the sample membranes at room temperature for 1 h. Wash with TBS for 10 min. Repeat this wash twice more.</li>
	<li>Incubate the membrane with anti-rabbit secondary antibody (1:5,000) for 30 min at room temperature.</li>
	<li>Wash with TBS for 10 min. Repeat this wash twice more.</li>
	<li>Visualize the chemiluminescence signals, and quantify signal intensities.</li>
</ol>

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No competing financial interests exist.

Epigenetic modifications play essential roles during brain development, maturation, and function. As a stable marker for DNA modification, dynamic 5-hmC responds to behavioral adaptation, neuronal activity, and is positively correlated with gene expression; thus, it is involved in the normal function of the brain and neurological disorder4. To explore its function in cells and tissues, it is necessary to detect the existence of 5-hmC and compare the level before and after treatment. Here, we demon...

Epigenetic modifications, including DNA modification, histone modification and RNA modification, have been shown to play essential functions in diverse biological processes and diseases1,2,3,4,5,6,7. For a long time, DNA methylation (i.e., 5-methylcytosine (5-mC)) has been viewed as a highly stable epigenetic marker and can not be further modified in the genome. Recently, it has been found that 5-mC could be oxidized to 5-hydroxymethylcytosine(5-hmC) by TET (Ten-eleven translocations) family proteins including TET1, TET2, and TET38,9. Further studies show that 5-hmC could serve as a stable marker and play biological roles through regulating gene expression4,10,11,12.
The present evidences indicate&#160;that 5-hmC is highly enriched in neuronal tissues/cells relative to other types of tissues in mammals, and exhibits dynamic features during neuronal development13,14. In the&#160;neuronal system, 5-hmC mediated epigenetic modifications play an important role in regulating neural stem cells, neuronal activity, learning and memory, and is involved in multiple neurological disorders including Rett syndrome, autism, Alzheimer&#8217;s disease, Huntington&#8217;s disease, etc.2,13,15,16,17,18,19,20.
There are several approaches for detecting 5-hmC in cells and tissues14,21,22,23,24. Here, we describe two methods to detect the existence of 5-hmC and quantify the global level of 5-hmC: immunofluorescence staining and DNA dot-blot. These two methods are convenient and sensitive, and have been successfully used in previous studies25,26,27,28,29,30. The key steps of these two methods are DNA denaturation. For immunofluorescence staining of 5-hmC, pre-treatment of samples with 1 M HCl is required. For 5-hmC dot-blot, DNA denaturation is performed with&#160;NaOH solution. These two methods together with next-generation sequencing are very useful tools for investigating the function of 5-hmC.

<table>
	<tbody>
		<tr>
			<td>4&#39;-6-diamidino-2-phenylindole (DAPI )</td>
			<td>Sigma-Aldrich</td>
			<td>D8417</td>
		</tr>
		<tr>
			<td>Adobe Photoshop software</td>
			<td>Adobe Inc.</td>
			<td>/</td>
		</tr>
		<tr>
			<td>Alexa Fluor 488 goat anti-rabbit IgG</td>
			<td>Thermo Fisher</td>
			<td>A11008</td>
		</tr>
		<tr>
			<td>Alexa Fluor 568 goat anti-mouse IgG</td>
			<td>Thermo Fisher</td>
			<td>A11001</td>
		</tr>
		<tr>
			<td>anti-5-hydroxymethylcytosine</td>
			<td>Active Motif</td>
			<td>39769</td>
		</tr>
		<tr>
			<td>anti-NeuN</td>
			<td>Millipore</td>
			<td>MAB377</td>
		</tr>
		<tr>
			<td>B27 supplement</td>
			<td>Gibco</td>
			<td>12587-010</td>
		</tr>
		<tr>
			<td>B27 supplement</td>
			<td>Gibco</td>
			<td>12580-010</td>
		</tr>
		<tr>
			<td>B27 supplement</td>
			<td>Gibco</td>
			<td>17504-044</td>
		</tr>
		<tr>
			<td>Cryostat microtome</td>
			<td>Leica</td>
			<td>CM1950</td>
		</tr>
		<tr>
			<td>DMEM/F-12 medium</td>
			<td>OmegaScientific</td>
			<td>DM25</td>
		</tr>
		<tr>
			<td>epidermal growth factor</td>
			<td>PeproTech</td>
			<td>100-15</td>
		</tr>
		<tr>
			<td>Fibroblast growth factor-basic</td>
			<td>PeproTech</td>
			<td>100-18B</td>
		</tr>
		<tr>
			<td>forskolin</td>
			<td>Sigma-Aldrich</td>
			<td>F6886</td>
		</tr>
		<tr>
			<td>GlutaMax</td>
			<td>Thermo</td>
			<td>35050061</td>
		</tr>
		<tr>
			<td>L-Glutamine</td>
			<td>Gibco</td>
			<td>25030-149</td>
		</tr>
		<tr>
			<td>neurobasal medium</td>
			<td>Gibco</td>
			<td>21103-049</td>
		</tr>
		<tr>
			<td>normal goat serum</td>
			<td>Vector Laboratories</td>
			<td>Z0325</td>
		</tr>
		<tr>
			<td>nylon membrane (Hybond&#8482;-N+ )</td>
			<td>Amersham Biosciences</td>
			<td>RPN303B</td>
		</tr>
		<tr>
			<td>OCT</td>
			<td>Leica</td>
			<td>14020108926</td>
		</tr>
		<tr>
			<td>Pen Strep</td>
			<td>Gibco</td>
			<td>15140-122</td>
		</tr>
		<tr>
			<td>phenol: chloroform: isoamyl alcohol (25: 24:1 )</td>
			<td>Sigma-Aldrich</td>
			<td>516726</td>
		</tr>
		<tr>
			<td>Poly-D-Lysine</td>
			<td>Sigma</td>
			<td>P0899-10</td>
		</tr>
		<tr>
			<td>proteinase K</td>
			<td>VVR</td>
			<td>39450-01-6</td>
		</tr>
		<tr>
			<td>retinoic acid</td>
			<td>Sigma-Aldrich</td>
			<td>R2625</td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Solarbio</td>
			<td>T8210</td>
		</tr>
	</tbody>
</table>

the detection of 5-hydroxymethylcytosine in neural stem cells and brains of mice

Multiple&#160;DNA modifications have been identified in the mammalian genome. Of that, 5-methylcytosine and 5-hydroxymethylcytosine-mediated epigenetic mechanisms have been intensively studied. 5-hydroxymethylcytosine displays dynamic features during embryonic and postnatal development of the brain, plays a regulatory function in gene expression, and is involved in multiple neurological disorders. Here, we describe the detailed methods including immunofluorescence staining and&#160;DNA dot-blot to detect 5-hydroxymethylcytosine in cultured cells and brain tissues of mouse.

To reveal the distribution of 5-hmC in the hippocampus of adult mice, we performed immunofluorescence with antibodies against neuronal cells (NeuN) and 5-hmC. In the hippocampus, 5-hmC co-localized well with neuronal cell marker NeuN (Figure 1A-H), suggesting an enrichment of 5-hmC in neurons.
To determine the dynamics of 5-hmC during neuronal development, a dot-blot was first performed with DNA samples isolated from proliferating and differentiat...

Watch this Scientific Journal Video about The Detection of 5-Hydroxymethylcytosine in Neural Stem Cells and Brains of Mice at JoVE.com

The Detection of 5-Hydroxymethylcytosine in Neural Stem Cells and Brains of Mice

Here, we present a protocol to detect 5-hydroxymethylcytosine in cells and brain tissues, utilizing immunofluorescence staining and DNA dot-blot methods.

Multiple&#160;DNA modifications have been identified in the mammalian genome. Of that, 5-methylcytosine and 5-hydroxymethylcytosine-mediated epigenetic ...

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Neuroscience

6.3K Views.  Zhejiang University. Here, we present a protocol to detect 5-hydroxymethylcytosine in cells and brain tissues, utilizing immunofluorescence staining and DNA dot-blot methods.

Video: The Detection of 5-Hydroxymethylcytosine in Neural Stem Cells and Brains of Mice

Isolation and Expansion of the Adult Mouse Neural Stem Cells Using the Neurosphere Assay

Isolation and expansion of the putative neural stem cells (NSCs) from the adult murine brain was first described by Reynolds and Weiss in 1992 employing a chemically defined serum-free culture system known as the neurosphere assay (NSA). In this assay, the majority of differentiated cell types die within a few days of culture but a small population of growth factor responsive precursor cells undergo active proliferation in the presence of epidermal growth factor (EGF) and/ basic fibroblastic growth factor (bFGF). These cells form colonies of undifferentiated cells called neurospheres, which in turn can be subcultured to expand the pool of neural stem cells. Moreover, the cells can be induced to differentiate, generating the three major cell types of the CNS i.e. neurons, astrocytes, and oligodendrocytes. This assay provides an invaluable tool to supply a consistent, renewable source of undifferentiated CNS precursors, which could be used for in vitro studies and also for therapeutic purposes.
This video demonstrates the NSA method to generate and expand NSCs from the adult mouse periventricular region, and provides technical insights to ensure one can achieve reproducible neurosphere cultures. The procedure includes harvesting the brain from the adult mouse, micro-dissection of the periventricular region, tissue preparation and culture in the NSA. The harvested tissue is first chemically digested using trypsin-EDTA and then mechanically dissociated in NSC medium to achieve a single cell suspension and finally plated in the NSA. After 7-10 days in culture, the resulting primary neurospheres are ready for subculture to reach the amount of cells required for future experiments.

This video protocol demonstrates the neurosphere assay method to generate and expand neural stem cells from the adult mouse periventricular region, and provides technical insights to ensure one can achieve reproducible neurosphere cultures.

Isolation and expansion of the putative neural stem cells (NSCs) from the adult murine brain was first described by Reynolds and Weiss in 1992 employing a ...

High Sensitivity 5-hydroxymethylcytosine Detection in Balb/C Brain Tissue

DNA hydroxymethylation is a long known modification of DNA, but has recently become a focus in epigenetic research. Mammalian DNA is enzymatically modified at the 5th carbon position of cytosine (C) residues to 5-mC, predominately in the context of CpG dinucleotides. 5-mC is amenable to enzymatic oxidation to 5-hmC by the Tet family of enzymes, which are believed to be involved in development and disease. Currently, the biological role of 5-hmC is not fully understood, but is generating a lot of interest due to its potential as a biomarker. This is due to several groundbreaking studies identifying 5-hydroxymethylcytosine in mouse embryonic stem (ES) and neuronal cells. Research techniques, including bisulfite sequencing methods, are unable to easily distinguish between 5-mC and 5-hmC . A few protocols exist that can measure global amounts of 5-hydroxymethylcytosine in the genome, including liquid chromatography coupled with mass spectrometry analysis or thin layer chromatography of single nucleosides digested from genomic DNA. Antibodies that target 5-hydroxymethylcytosine also exist, which can be used for dot blot analysis, immunofluorescence, or precipitation of hydroxymethylated DNA, but these antibodies do not have single base resolution.In addition, resolution depends on the size of the immunoprecipitated DNA and for microarray experiments, depends on probe design. Since it is unknown exactly where 5-hydroxymethylcytosine exists in the genome or its role in epigenetic regulation, new techniques are required that can identify locus specific hydroxymethylation. The EpiMark 5-hmC and 5-mC Analysis Kit provides a solution for distinguishing between these two modifications at specific loci. The EpiMark 5-hmC and 5-mC Analysis Kit is a simple and robust method for the identification and quantitation of 5-methylcytosine and 5-hydroxymethylcytosine within a specific DNA locus. This enzymatic approach utilizes the differential methylation sensitivity of the isoschizomers MspI and HpaII in a simple 3-step protocol. Genomic DNA of interest is treated with T4-BGT, adding a glucose moeity to 5-hydroxymethylcytosine. This reaction is sequence-independent, therefore all 5-hmC will be glucosylated; unmodified or 5-mC containing DNA will not be affected. This glucosylation is then followed by restriction endonuclease digestion. MspI and HpaII recognize the same sequence (CCGG) but are sensitive to different methylation states. HpaII cleaves only a completely unmodified site: any modification (5-mC, 5-hmC or 5-ghmC) at either cytosine blocks cleavage. MspI recognizes and cleaves 5-mC and 5-hmC, but not 5-ghmC. The third part of the protocol is interrogation of the locus by PCR. As little as 20 ng of input DNA can be used. Amplification of the experimental (glucosylated and digested) and control (mock glucosylated and digested) target DNA with primers flanking a CCGG site of interest (100-200 bp) is performed. If the CpG site contains 5-hydroxymethylcytosine, a band is detected after glucosylation and digestion, but not in the non-glucosylated control reaction. Real time PCR will give an approximation of how much hydroxymethylcytosine is in this particular site. In this experiment, we will analyze the 5-hydroxymethylcytosine amount in a mouse Babl/C brain sample by end point PCR.

The EpiMark 5-hmC and 5-mC Analysis Kit can be used to analyze and quantitate 5-methylcytosine and 5-hydroxymethylcytosine within a spe cific locus. The kit distinguishes 5-mC from 5-hmC by the addition of glucose to the hydroxyl group of 5-hmC via an enzymatic reaction utilizing &beta;-glucosyltransferase (T4-BGT). When 5-hmC occurs In the context of CCGG, this modification converts a cleavable MspI site to a non-cleavable site.

DNA hydroxymethylation is a long known modification of DNA, but has recently become a focus in epigenetic research.   Mammalian DNA is enzymatically ...

Surgical Transplantation of Mouse Neural Stem Cells into the Spinal Cords of Mice Infected with Neurotropic Mouse Hepatitis Virus

Mice infected with the neurotropic JHM strain of mouse hepatitis virus (MHV) develop pathological and clinical outcomes similar to patients with the demyelinating disease Multiple Sclerosis (MS). We have shown that transplantation of NSCs into the spinal cords of sick mice results in a significant improvement in both remyelination and in clinical outcome. Cell replacement therapies for the treatment of chronic neurologic diseases are now a reality and in vivo models are vital in understanding the interactions between the engrafted cells and host tissue microenvironment. This presentation provides an adapted method for transplanting cells into the spinal cord of JHMV-infected mice. In brief, we provide a procedure for i) preparation of NSCs prior to transplant, ii) pre-operative care of mice, iii) exposure of the spinal cord via laminectomy, iv) stereotactic injection of NSCs, and iv) post-operative care.

The transplantation of mouse neural stem cells (NSCs) into the spinal cords of mice with established demyelination is detailed. The preparation of NSCs, the laminectomy of thoracic vertebra 9 (T9), and transplantation of NSCs is outlined along with the pre- and post-operative care of the mice.

Mice infected with the neurotropic JHM strain of mouse hepatitis virus (MHV) develop pathological and clinical outcomes similar to patients with the ...

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

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

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

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

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 ...

One Mouse, Two Cultures: Isolation and Culture of Adult Neural Stem Cells from the Two Neurogenic Zones of Individual Mice

The neurosphere assay and the adherent monolayer culture system are valuable tools to determine the potential (proliferation or differentiation) of adult neural stem cells in vitro. These assays can be used to compare the precursor potential of cells isolated from genetically different or differentially treated animals&#160;to determine the effects of exogenous factors on neural precursor cell proliferation and differentiation and to generate neural precursor cell lines that can be assayed over continuous passages. The neurosphere assay is traditionally used for the post-hoc identification of stem cells, primarily due to the lack of definitive markers with which they can be isolated from primary tissue&#160;and has the major advantage of giving a quick estimate of precursor cell numbers in brain tissue derived from individual animals. Adherent monolayer cultures, in contrast, are not traditionally used to compare proliferation between individual animals, as each culture is generally initiated from the combined tissue of between 5-8 animals. However, they have the major advantage that, unlike neurospheres, they consist of a mostly homogeneous population of precursor cells and are useful for following the differentiation process in single cells. Here, we describe, in detail, the generation of neurosphere cultures and, for the first time, adherent cultures from individual animals. This has many important implications including paired analysis of proliferation and/or differentiation potential in both the subventricular zone (SVZ) and dentate gyrus (DG) of treated or genetically different mouse lines, as well as a significant reduction in animal usage.

Here we describe a detailed protocol for the simultaneous generation of neural precursor cell cultures, as either adherent monolayers or neurospheres, from the subventricular zone and dentate gyrus of individual adult mice.

The neurosphere assay and the adherent monolayer culture system are valuable tools to determine the potential (proliferation or differentiation) of adult ...

Feeder-free Derivation of Neural Crest Progenitor Cells from Human Pluripotent Stem Cells

Human pluripotent stem cells (hPSCs) have great potential for studying human embryonic development, for modeling human diseases in the dish and as a source of transplantable cells for regenerative applications after disease or accidents. Neural crest (NC) cells are the precursors for a large variety of adult somatic cells, such as cells from the peripheral nervous system and glia, melanocytes and mesenchymal cells. They are a valuable source of cells to study aspects of human embryonic development, including cell fate specification and migration. Further differentiation of NC progenitor cells into terminally differentiated cell types offers the possibility to model human diseases in vitro, investigate disease mechanisms and generate cells for regenerative medicine. This article presents the adaptation of a currently available in vitro differentiation protocol for the derivation of NC cells from hPSCs. This new protocol requires 18 days of differentiation, is feeder-free, easily scalable and highly reproducible among human embryonic stem cell (hESC) lines as well as human induced pluripotent stem cell (hiPSC) lines. Both old and new protocols yield NC cells of equal identity.

Neural crest (NC) cells derived from human pluripotent stem cells (hPSC) have great potential for modeling human development and disease and for cell replacement therapies. Here, a feeder-free adaptation of the currently widely used in vitro differentiation protocol for the derivation of NC cells from hPSCs is presented.

Human pluripotent stem cells (hPSCs) have great potential for studying human embryonic development, for modeling human diseases in the dish and as a ...

Enumeration of Neural Stem Cells Using Clonal Assays

Neural stem cells (NSCs) have the ability to self-renew and generate the three major neural lineages &#8212; astrocytes, neurons and oligodendrocytes. NSCs and neural progenitors (NPs) are commonly cultured in vitro as neurospheres. This protocol describes in detail how to determine the NSC frequency in a given cell population under clonal conditions. The protocol begins with the seeding of the cells at a density that allows for the generation of clonal neurospheres. The neurospheres are then transferred to chambered coverslips and differentiated under clonal conditions in conditioned medium, which maximizes the differentiation potential of the neurospheres. Finally, the NSC frequency is calculated based on neurosphere formation and multipotency capabilities. Utilities of this protocol include the evaluation of candidate NSC markers, purification of NSCs, and the ability to distinguish NSCs from NPs. This method takes 13 days to perform, which is much shorter than current methods to enumerate NSC frequency.

Neural stem cells (NSCs) refer to cells&#160;which can self-renew and differentiate into the three neural lineages. Here, we describe a protocol to determine NSC frequency in a given cell population using neurosphere formation and differentiation under clonal conditions.

Neural stem cells (NSCs) have the ability to self-renew and generate the three major neural lineages &#8212; astrocytes, neurons and oligodendrocytes. ...

Isolation and Culture of Adult Neural Stem Cells from the Mouse Subcallosal Zone

Adult neural stem cells (aNSCs) can be used for the regeneration of damaged brain tissue. NSCs have the potential for differentiation and proliferation into three types of cells: neurons, astrocytes, and oligodendrocytes. Identifying aNSC-derived regions and characterizing the aNSC properties are critical for the potential use of aNSCs and for the elucidation of their role in neural regeneration. The subcallosal zone (SCZ), located between white matter and the hippocampus, has recently been reported to contain aNSCs and continuously give rise to neuroblasts. A low percentage of aNSCs from the SCZ is differentiated into neurons; most cells are differentiated into glial cells, such as oligodendrocytes and astrocytes. These cells are suggested to have a therapeutic potential for traumatic cortical injury. This protocol describes in detail the process to generate SCZ-aNSCs from an adult mouse brain. A brain matrix with intervals of 1 mm is used to obtain the SCZ-containing coronal slices and to precisely dissect the SCZ from the whole brain. The SCZ sections are initially subjected to a neurosphere culture. A well-developed culture system allows for the verification of their characteristics and can increase research on NSCs. A neurosphere culture system provides a useful tool for determining proliferation and collecting the genuine NSCs. A monolayer culture is also an in vitro system to assay proliferation and differentiation. Significantly, this culture system provides a more homogenous environment for NSCs than the neurosphere culture system. Thus, using a discrete brain region, these culture systems will be helpful for expanding our knowledge about aNSCs and their applications for therapeutic uses.

Establishing culture systems for the expansion of adult neural stem cells (aNSCs) allows for the examination and application of aNSCs for therapy. The subcallosal zone (SCZ) has recently been recognized as a novel neuroblast-forming region in adult mice. Here, methods for the isolation, expansion, and differentiation of SCZ-aNSCs are described.

Adult neural stem cells (aNSCs) can be used for the regeneration of damaged brain tissue. NSCs have the potential for differentiation and proliferation ...

Development of a Refined Protocol for Trans-scleral Subretinal Transplantation of Human Retinal Pigment Epithelial Cells into Rat Eyes

Degenerative retinal diseases such as age-related macular degeneration (AMD) are the leading cause of irreversible vision loss worldwide. AMD is characterized by the degeneration of retinal pigment epithelial (RPE) cells, which are a monolayer of cells functionally supporting and anatomically wrapping around the neural retina. Current pharmacological treatments for the non-neovascular AMD (dry AMD) only slow down the disease progression but cannot restore vision, necessitating studies aimed at identifying novel therapeutic strategies. Replacing the degenerative RPE cells with healthy cells holds promise to treat dry AMD in the future. Extensive preclinical studies of stem cell replacement therapies for AMD involve the transplantation of stem cell-derived RPE cells into the subretinal space of animal models, in which the subretinal injection technique is applied. The approach most frequently used in these preclinical animal studies is through the trans-scleral route, which is made difficult by the lack of direct visualization of the needle end and can often result in retinal damage. An alternative approach through the vitreous allows for direct observation of the needle end position, but it carries a high risk of surgical traumas as more eye tissues are disturbed. We have developed a less risky and reproducible modified trans-scleral injection method that uses defined needle angles and depths to successfully and consistently deliver RPE cells into the rat subretinal space and avoid excessive retinal damage. Cells delivered in this manner have been previously demonstrated to be efficacious in the Royal College of Surgeons (RCS) rat for at least 2 months. This technique can be used not only for cell transplantation but also for delivery of small molecules or gene therapies.

Subretinal injection has been widely applied in preclinical studies of stem cell replacement therapy for age-related macular degeneration. In this visualized article, we describe a less risky, reproducible and precisely modified subretinal injection technique via the trans-scleral approach to deliver cells into rat eyes.