This work was supported by the Royan Institute.

All the surgeries and procedures on animal were approved by the animal ethics committee of the Royan Institute, Tehran, Iran.
1. Preparation of Surgical Instruments, Washing Buffer (HEPES-MEM), Cell Culture Media and Cell Culture Plates
<ol>
	<li>Sterilize the surgical tools (scissors, scalpel blade handle and forceps) by autoclaving them based on the routine sterilization guidelines.</li>
	<li>Prepare an adequate volume of HEPES-MEM buffer (around 100 mL is enough for each pregnant mice). Add high concentrations of antibiotics (10% penicillin/streptomycin) to the HEPES-MEM buffer. This concentration of antibiotics is necessary to reduce the risk of microbial contamination.
	<ol>
		<li>To prepare HEPES-MEM buffer, add 0.5958 g of HEPES powder to 100 mL of MEM (minimum essential medium), and mix well. Adjust the pH to 7.3-7.4 and filter the medium using a 0.22 &#181;m filter.</li>
	</ol>
	</li>
	<li>Make NSC medium containing neurobasal medium (NB), supplemented with 20 ng/mL EGF, 10 ng/mL bFGF, 1% 100x N2 supplement or 1% B27 supplement (without vitamin A), 1 U/mL Heparin, 1% L-glutamine, 1% non-essential amino acid (NEAA), 1% Penicillin/streptomycin, and 0.1 mM &#946;-mercaptoethanol.</li>
</ol>
2. Animal Surgery and Micro-Dissection
<ol>
	<li>Anesthetize a pregnant mouse on the 13th day of gestation (here, use BALB/c strain aged 4 months) by intraperitoneal injection of ketamine-xylazine, 100 mg/kg and 10 mg/kg by body weight respectively.
	<ol>
		<li>Confirm deep anesthesia by exerting a painful stimulus (e.g., pinch with forceps) on the animal&#39;s foot and when there is no pain reflex, sacrifice the animal by cervical dislocation.</li>
	</ol>
	</li>
	<li>Clean and disinfectant the skin of the abdomen by spraying 70% ethanol.</li>
	<li>Control the skin over the abdomen and then cut the skin and the underlying fascia with scissors to uncover the abdominal cavity and uterine horns.
	<ol>
		<li>Remove the uterine horns containing the embryos by scissors and transfer them into a 50 mL conical tube containing 25 mL of cold HEPES-MEM buffer.</li>
		<li>Place the conical tube under the laminar flow hood and open the cap under the hood. Bring the uterine horns out from the tube and rinse 3 times with enough volume of the fresh cold HEPES-MEM buffer to eliminate debris and blood.</li>
	</ol>
	</li>
	<li>Transfer the uterine tissue to a 10 cm Petri dish containing 7-10 mL of cold HEPES-MEM buffer. Open the uterine horns using fine scissors and transfer embryos to a new dish containing 7-10 mL of cold HEPES-MEM buffer. Now put the 10 cm dish with embryos under the dissecting microscope for the micro-dissection operation.</li>
	<li>Bend the tip of a 25-27 G syringe needle by pushing its tip on a steel scalpel blade handle. Bend the tip of the needle until the tip is bent at an angle of 70-90&#176;. Check the tip of the needle under the dissecting microscope to see the bend at the tip of the needle. 
	NOTE: Naturally, embryos have a lateral position in the dish.</li>
	<li>Without changing their position, hold the neck and body of the embryo with fine forceps and then insert the bent part of the needle tip into the frontal fontanelle of the embryo head. There would be small bleeding or a blood clot there.
	<ol>
		<li>Move the needle tip superficially. While the bent part is inside the bulge toward the forehead and then toward back of the head, make sure to cut through the skin and the skull and not to damage the underlying brain.</li>
		<li>Push the skin with the needle tip laterally to uncover the brain and insert the needle from the lateral side of the skin to the area underneath the brain. Remove the brain from the skull by pushing it to come out from the dissected skull.</li>
		<li>Hold the brain steady using the curved forceps and cut the cortex of each hemisphere using micro-scissors to expose the ganglionic eminence.</li>
		<li>Hold the brain and place the dissected ganglionic eminence into the 15 mL centrifuge tube containing neural stem cell medium. The ganglionic eminence is clearly shown with its middle and lateral parts.</li>
		<li>Repeat this procedure until all the brains have been micro-dissected.</li>
	</ol>
	</li>
	<li>Cut the dissected ganglionic eminence by placing the pipette tip against the bottom of the tube. Pipette the suspension up and down 4 to 5 times to break up the tissue for a single cell suspension.
	<ol>
		<li>Centrifuge the suspension at 110 x g for 5 min. Remove the supernatant and re-suspend the cells in 1 mL of 0.05% trypsin-EDTA.</li>
		<li>Incubate the cell suspension in a 37 &#176;C for 10 min, and then add an equivalent volume of soybean trypsin inhibitor (25 &#181;g/mL) to stop the trypsin activity. Pipette the cell suspension up and down to make sure that the trypsin has been totally inactivated.</li>
		<li>Centrifuge the cell suspension at 110 x g for 5 min. Remove the supernatant and re-suspend the cells in 1 mL of complete NSC medium and count the number of cells.</li>
	</ol>
	</li>
	<li>Plate the cells (2x105 cells/mL) at NSC medium into the suitable size tissue culture flask. Transfer 5 mL to T25, 20 mL to T75 and 40 mL to T175 flasks. 
	NOTE: Neurospheres will appear after 3-days culture at 37 &#176;C in a humidified incubator with 5% CO2. After 6-7 days, the spheres should measure between 150-200 &#181;m in diameter and will be ready for subculture.By cultivating one million primary NSCs after seven days the number of cells will increase to 3-4 million.</li>
</ol>
3. Trypsinization and Passaging of Neurospheres
<ol>
	<li>To subculture the neurospheres, transfer the medium with suspended neurospheres to the centrifuge tube, centrifuge at 110 x g for 5 min and then discard the supernatant. Add 1 mL of 0.05% trypsin-EDTA and incubate at 37&#176;C for 10 min.
	<ol>
		<li>Inactivate the trypsin using soybean trypsin inhibitor and pipette the neurospheres gently up and down to make them single cells.</li>
	</ol>
	</li>
	<li>Centrifuge the cell suspension at 110 x g for 5 min, discard the supernatant and re-suspend the cells in 1 mL of NSC medium. These cells are ready for next subculture or culture on Laminin and Poly-L-Ornithine coated surfaces for advanced experiments.</li>
	<li>For the next subculture, transfer NSCs into the new flask (follow step 2.8) and culture them in the NSC medium. For induction of neuronal differentiation culture NSCs in the NSC medium in the absence of bFGF and EGF on Laminin and Poly-L-Ornithine coated plates (Figure 1B).</li>
	<li>For the coating procedure, fully coat the cell culture surface by adding enough volume of diluted poly-L-ornithine solution (25 &#181;g/mL) to the cell culture plate and incubate at 37 &#176;C for 2 h.
	<ol>
		<li>Aspirate the poly-L-ornithine and rinse the well 2x with PBS. Add enough volume of 5 &#181;g/mL laminin to completely cover the culture surface area and incubate at 37 &#176;C for 2 h. Aspirate the laminin before plating cells or store plate at 4 &#176;C until needed.</li>
	</ol>
	</li>
</ol>
4. Flow Cytometry Assay
NOTE: The expression of specific markers of NSCs, neurons and glial cells can be measured by flow cytometry assay13. The protocol is based on Menon et al.,13 with minor modifications.
<ol>
	<li>Dissociate neurospheres or detach cultured NSCs from coated plates by trypsinization to make them single cells. Add 500 &#181;L of fixation buffer (2% paraformaldehyde (PFA) in PBS) to 100 &#181;L of the cell suspension (around 1 million cells are enough for staining with each antibody), and then incubate the tubes at RT for 15 min.</li>
	<li>Wash cells by adding 1 mL of PBS to the tube and centrifuge at 110 x g for 5 min. Discard the supernatant and resuspend the cell pellet, leaving approximately 100 &#181;L in the tube.
	<ol>
		<li>Permeabilize cells with Tween-20 (0.7% Tween-20 in PBS) by adding 500 &#181;L of Tween-20 buffer to 100 &#181;L of cell suspension. Incubate the tubes at RT for 15 min on an orbital shaker (100 rpm).</li>
	</ol>
	</li>
	<li>Repeat the centrifugation and the PBS wash. Remove the supernatant from the tubes completely, leaving only the pellet behind. Add 100 &#181;L of diluted primary antibodies (rabbit anti mouse &#946;tub-III, GFAP and Nestin antibodies at 1:200 concentration) in dilution buffer containing 1% bovine serum albumin, 10% serum (goat serum) and 0.5% Tween-20 in PBS and gently triturate to mix. Incubate the tubes at RT for 30 min on an orbital shaker.</li>
	<li>Wash the cells once with PBS and remove the supernatant from the tubes completely, leaving only the pellet behind.
	<ol>
		<li>Add 100 &#181;L of diluted secondary antibody (goat anti rabbit FITC conjugated at 1:500 concentration) in PBS to the cell pellet and gently triturate to mix. Incubate the tubes at RT for 30 min on a shaker in the dark.</li>
		<li>Wash the samples 2x with PBS and then wash once with flow buffer. Centrifuge and re-suspend the cells in approximately 150 &#181;L of flow buffer for flow cytometer analysis.</li>
	</ol>
	</li>
</ol>

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No conflict of interest declared.

Using a suitable source of neural stem cells is very important for neuroscientists. Neural stem cells could be harvested from different areas of the embryo brain and they can generate specific types of neurons and glial cells. There are several methods for induction of differentiation of neural stem cells to induce them to generate mature neurons and glial cells. There are numerous reports indicating that under specific culture conditions and trophic factor regiments, they could generate neurons14...

Neural stem cells (NSCs) reside in different regions of the adult and embryo brain and they have a tendency to generate different types of neurons and glial cell1. The subventricular zones in the adult mammalian brain2 and ganglionic eminence in the embryo brain are NSC rich regions3. In the developing brain, the ganglionic eminence delivers most of the cortical interneurons and particularly GABAergic interneurons3. There are also less invasive methods for neural stem cell generation from embryonic stem cells (ESCs) or induced pluripotent stem cells (iPSCs) that reduce the demand for animal use. Despite the fact that generating NSCs from ESCs or iPSCs is possible4,5, it has some advantages and disadvantages compared to the isolation of neural stem cells from the adult or embryo brain6,7,8. The protocols for inducing the differentiation of ESCs and iPSCs toward neuronal phenotypes are always time and cost consuming and the rate of success (70-80% Nestin positive cells)5 is lower compared with direct isolation of NSCs from the animal brain (more than 99% Nestin positive cells)9. Moreover, stem cells lose their genetic stability and differentiation tendency after several passages10,11. Even though there are other new reports about direct conversion of somatic cells into NSCs, these cells are genetically engineered and are not easily accessible in every lab12. Therefore, there is still a big demand for isolation of neural stem cells from the animal brain; it is possible to reduce the quantity of animal usage by improving the surgical techniques. By reducing the surgical time and improving the techniques, it is possible to keep cells away from damage and obtain the highest rate of NSCs from each animal.
Here, we introduce a simplified and reproducible technique for isolation of neural stem cells from mouse E13 embryo brain.

<table border="0" cellpadding="0" cellspacing="0" style="width:942px;" width="941">
	<tbody>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">15 mL tubes</td>
			<td dir="LTR" style="width:145px;">Falcon</td>
			<td dir="LTR" style="width:235px;">352097</td>
			<td style="width:172px;"></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">50 mL tubes</td>
			<td dir="LTR" style="width:145px;">Falcon</td>
			<td dir="LTR">352235</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">Adson Forceps, 12 cm, Straight</td>
			<td dir="LTR" style="width:145px;">WPI</td>
			<td dir="LTR">14226</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">B27</td>
			<td dir="LTR" style="width:145px;">Gibco</td>
			<td dir="LTR" style="width:235px;">17504-44</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">bFGF</td>
			<td dir="LTR" style="width:145px;">Sigma</td>
			<td dir="LTR" style="width:235px;">F0291</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:389px;">bovine serum albumin (BSA)</td>
			<td style="width:145px;">Sigma</td>
			<td style="width:235px;">A2153</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;">dish 10cm&#160;</td>
			<td dir="LTR" style="width:145px;">Falcon</td>
			<td dir="LTR" style="width:235px;">353003</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">Dressing Forceps, 12.5 cm, Straight</td>
			<td dir="LTR" style="width:145px;">WPI</td>
			<td dir="LTR">15908</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;">Dumont Tweezers, 11 cm, Straight</td>
			<td dir="LTR" style="width:145px;">WPI</td>
			<td dir="LTR" style="width:235px;">500342</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">EGF</td>
			<td dir="LTR" style="width:145px;">Sigma</td>
			<td dir="LTR" style="width:235px;">E9644</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;">Ethanol</td>
			<td dir="LTR" style="width:145px;">Merck</td>
			<td dir="LTR" style="width:235px;">100983&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">Glutamate</td>
			<td dir="LTR" style="width:145px;">Sigma&#160;</td>
			<td dir="LTR" style="width:235px;">G3291</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">Glutamax</td>
			<td dir="LTR" style="width:145px;">Gibco</td>
			<td dir="LTR" style="width:235px;">35050061</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:389px;">goat anti rabbit FITC conjugated secondary antibody</td>
			<td style="width:145px;">Sigma</td>
			<td style="width:235px;">AP307F</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:389px;">goat serum</td>
			<td style="width:145px;">Sigma</td>
			<td style="width:235px;">G9023</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;">Heparin&#160;&#160;</td>
			<td dir="LTR" style="width:145px;">Sigma</td>
			<td dir="LTR" style="width:235px;">h3149</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">HEPES</td>
			<td dir="LTR" style="width:145px;">Sigma</td>
			<td dir="LTR" style="width:235px;">83264</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">HEPES</td>
			<td dir="LTR" style="width:145px;">Sigma</td>
			<td dir="LTR">90909C</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;">insulinsyringe with 25-27 gauge Needle&#160;</td>
			<td dir="LTR" style="width:145px;">SUPA medical</td>
			<td dir="LTR">A1SNL127</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">laminin</td>
			<td dir="LTR" style="width:145px;">sigma&#160;&#160;&#160;</td>
			<td dir="LTR" style="width:235px;">L2020</td>
			<td></td>
		</tr>
		<tr height="26">
			<td dir="LTR" height="26" style="height:26px;width:389px;">MEM</td>
			<td dir="LTR" style="width:145px;">Sigma</td>
			<td dir="LTR" style="width:235px;">M2279</td>
			<td></td>
		</tr>
		<tr height="26">
			<td dir="LTR" height="26" style="height:26px;width:389px;">N2 supplement</td>
			<td dir="LTR" style="width:145px;">Gibco</td>
			<td dir="LTR" style="width:235px;">17502048</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">NB medium</td>
			<td dir="LTR" style="width:145px;">Gibco</td>
			<td dir="LTR" style="width:235px;">21103-31</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">Non-essential amino acid (NEAA)</td>
			<td dir="LTR" style="width:145px;">Gibco</td>
			<td dir="LTR" style="width:235px;">11140050</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">PBS without Ca and Mg</td>
			<td dir="LTR" style="width:145px;">Gibco</td>
			<td dir="LTR">20012050</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">Penicilin/ Streptomycin</td>
			<td dir="LTR" style="width:145px;">Gibco</td>
			<td dir="LTR" style="width:235px;">5140122</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">Poly-L-ornithine</td>
			<td dir="LTR" style="width:145px;">Sigma</td>
			<td dir="LTR" style="width:235px;">&#160;P4957</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:389px;">rabbit anti mouse beta tubulin-III antibody</td>
			<td style="width:145px;">Sigma</td>
			<td style="width:235px;">T2200</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:389px;">rabbit anti mouse GFAP antibody</td>
			<td style="width:145px;">Sigma</td>
			<td style="width:235px;">G4546</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:389px;">rabbit anti mouse Nestin antibody</td>
			<td style="width:145px;">Sigma</td>
			<td style="width:235px;">N5413</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">Scalpel Handle #3</td>
			<td dir="LTR" style="width:145px;">WPI</td>
			<td dir="LTR">500236</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;">Scissors curve</td>
			<td dir="LTR" style="width:145px;">WPI</td>
			<td dir="LTR" style="width:235px;">14396</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">Scissors sharp straight</td>
			<td dir="LTR" style="width:145px;">WPI</td>
			<td dir="LTR">14192</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;">Soybean trypsin inhibitor</td>
			<td dir="LTR" style="width:145px;">Roche</td>
			<td dir="LTR" style="width:235px;">10109886001&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;">Tissue culture flasks, T25</td>
			<td dir="LTR" style="width:145px;">BD</td>
			<td dir="LTR" style="width:235px;">353014</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;">Tissue culture flasks, T75</td>
			<td dir="LTR" style="width:145px;">BD</td>
			<td dir="LTR" style="width:235px;">353024</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:389px;">Tween 20</td>
			<td style="width:145px;">Sigma</td>
			<td style="width:235px;">P1379</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;">Vannas Scissors,&#160; 8 cm, Straight&#160;</td>
			<td dir="LTR" style="width:145px;">WPI</td>
			<td>14003</td>
			<td></td>
		</tr>
		<tr height="21">
			<td dir="LTR" height="21" style="height:21px;width:389px;">&#946;-mercaptoethanol</td>
			<td dir="LTR" style="width:145px;">Sigma</td>
			<td dir="LTR">M6250</td>
			<td></td>
		</tr>
	</tbody>
</table>

isolation and culture of embryonic mouse neural stem cells

Neural stem cells (NSCs) are multipotent and can give rise to the three major cell types of the central nervous system (CNS). In vitro culture and expansion of NSCs provide a suitable source of cells for neuroscientists to study the function of neurons and glial cells along with their interactions. There are several reported techniques for the isolation of neural stem cells from adult or embryo mammalian brains. During the microsurgical operation to isolate NSCs from different regions of the embryonic CNS, it is very important to reduce the damage to the brain cells to obtain the highest ratio of live and expandable stem cells. A possible technique for stress reduction during isolation of these cells from the mouse embryo brain is the reduction of surgical time. Here, we demonstrate a developed technique for rapid isolation of these cells from the E13 mouse embryo ganglionic eminence. Surgical procedures include harvesting E13 mouse embryos from the uterus, cutting the frontal fontanelle of the embryo with a bent needle tip, extracting the brain from the skull, microdissection of the isolated brain to harvest the ganglionic eminence, dissociation of the harvested tissue in NSC medium to gain a single cell suspension, and finally plating cells in suspension culture to generate neurospheres.

Micro-Dissection, Cell Isolation and Neurosphere Culture. Here, we presented a rapid and efficient method for mouse E13 brain microsurgery and isolation of neural stem cells. This article shows that it is possible to remove the whole brain from an E13 mouse embryo skull through a fine rupture in frontal fontanelle. With this method, the brain endures less damage and it is possible to isolate cells from different parts of the brain. The harvested cell...

Watch this Scientific Journal Video about Isolation and Culture of Embryonic Mouse Neural Stem Cells at JoVE.com

Isolation and Culture of Embryonic Mouse Neural Stem Cells

Here, we introduce a novel microsurgical technique for the isolation of neural stem cells from the E13 mouse embryo ganglionic eminence.

Neural stem cells (NSCs) are multipotent and can give rise to the three major cell types of the central nervous system (CNS). In vitro culture and ...

isolation-and-culture-of-embryonic-mouse-neural-stem-cells

Research

JoVE Journal

Neuroscience

17.7K Views.  ACECR. Here, we introduce a novel microsurgical technique for the isolation of neural stem cells from the E13 mouse embryo ganglionic eminence.

Video: Isolation and Culture of Embryonic Mouse Neural Stem Cells

Dissection and Culture of Commissural Neurons from Embryonic Spinal Cord

Commissural neurons have been widely used to investigate the mechanisms underlying axon guidance during embryonic spinal cord development. The cell bodies of these neurons are located in the dorsal spinal cord and their axons follow stereotyped trajectories during embryonic development. Commissural axons initially project ventrally towards the floorplate. After crossing the midline, these axons turn anteriorly and project towards the brain. Each of these steps is regulated by the action of several guidance cues. Cultures highly enriched in commissural neurons are ideally suited for many experiments addressing the mechanisms of axon pathfinding, including turning assays, immunochemistry and biochemistry. Here, we describe a method to dissect and culture commissural neurons from E13 rat dorsal spinal cord. First, the spinal cord is isolated and dorsal strips are dissected out. The dorsal tissue is then dissociated into a cell suspension by trypsinization and mechanical disruption. Neurons are plated onto poly-L-lysine-coated glass coverslips or tissue-culture dishes. After 30 hours in vitro, most neurons have extended an axon. The purity of the culture (Yam et al. 2009), typically over 90%, can be assessed by immunolabeling with the commissural neuron markers DCC, LH2 and TAG1 (Helms and Johnson, 1998). This neuronal preparation is a useful tool for in vitro studies of the cellular and molecular mechanisms of commissural axon growth and guidance during spinal cord development.

This video demonstrates a method to dissect and culture commissural neurons from E13 rat dorsal spinal cord. Dissociated commissural neurons are useful to study the cellular and molecular mechanisms of axon growth and guidance.

Commissural neurons have been widely used to investigate the mechanisms underlying axon guidance during embryonic spinal cord development. The cell bodies ...

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 ...

Establishing Embryonic Mouse Neural Stem Cell Culture Using the Neurosphere Assay

In mammalians, stem cells acts as a source of undifferentiated cells to maintain cell genesis and renewal in different tissues and organs during the life span of the animal. They can potentially replace cells that are lost in the aging process or in the process of injury and disease. The existence of neural stem cells (NSCs) was first described by Reynolds and Weiss (1992) in the adult mammalian central nervous system (CNS) using a novel serum&#8208;free culture system, the neurosphere assay (NSA). Using this assay, it is also feasible to isolate and expand NSCs from different regions of the embryonic CNS. These in vitro expanded NSCs are multipotent and can give rise to the three major cell types of the CNS. While the NSA seems relatively simple to perform, attention to the procedures demonstrated here is required in order to achieve reliable and consistent results. This video practically demonstrates NSA to generate and expand NSCs from embryonic day 14-mouse brain tissue and provides technical details so one can achieve reproducible neurosphere cultures. The procedure includes harvesting E14 mouse embryos, brain microdissection to harvest the ganglionic eminences, dissociation of the harvested tissue in NSC medium to gain a single cell suspension, and finally plating cells in NSA culture. After 5-7 days in culture, the resulting primary neurospheres are passaged to further expand the number of the NSCs for future experiments.

This video protocol demonstrates the application of the neurosphere assay for the isolation and expansion of neural stem cells from the ganglionic eminences of embryonic day 14-mouse brain.

In mammalians, stem cells acts as a source of undifferentiated cells to maintain cell genesis and renewal in different tissues and organs during the life ...

Isolation and Culture of Neural Crest Stem Cells from Human Hair Follicles

Hair follicles undergo lifelong growth and hair cycle is a well-controlled process involving stem cell proliferation and quiescence. Hair bulge is a well-characterized niche for adult stem cells1. This segment of the outer root sheath contains a number of different types of stem cells, including epithelial stem cells2, melanocyte stem cells3 and neural crest like stem cells4-7. Hair follicles represent an accessible and rich source for different types of human stem cells. We and others have isolated neural crest stem cells (NCSCs) from human fetal and adult hair follicles4,5. These human stem cells are label-retaining cells and are capable of self-renewal through asymmetric cell division in vitro. They express immature neural crest cell markers but not differentiation markers. Our expression profiling study showed that they share a similar gene expression pattern with murine skin immature neural crest cells. They exhibit clonal multipotency that can give rise to myogenic, melanocytic, and neuronal cell lineages after in vitro clonal single cell culture. Differentiated cells not only acquire lineage-specific markers but also demonstrate appropriate functions in ex vivo conditions. In addition, these NCSCs show differentiation potential toward mesenchymal lineages. Differentiated neuronal cells can persist in mouse brain and retain neuronal differentiation markers. It has been shown that hair follicle derived NCSCs can help nerve regrowth, and they improve motor function in mice transplanted with these stem cells following transecting spinal cord injury8. Furthermore, peripheral nerves have been repaired with stem cell grafts9, and implantation of skin-derived precursor cells adjacent to crushed sciatic nerves has resulted in remyelination10. Therefore, the hair follicle/skin derived NCSCs have already shown promising results for regenerative therapy in preclinical models.
Somatic cell reprogramming to induced pluripotent stem (iPS) cells has shown enormous potential for regenerative medicine. However, there are still many issues with iPS cells, particularly the long term effect of oncogene/virus integration and potential tumorigenicity of pluripotent stem cells have not been adequately addressed. There are still many hurdles to be overcome before iPS cells can be used for regenerative medicine. Whereas the adult stem cells are known to be safe and they have been used clinically for many years, such as bone marrow transplant. Many patients have already benefited from the treatment. Autologous adult stem cells are still preferred cells for transplantation. Therefore, the readily accessible and expandable adult stem cells in human skin/hair follicles are a valuable source for regenerative medicine.

This article presents a robust protocol for isolation and culture of neural crest stem cells from human hair follicles.

Hair follicles undergo lifelong growth and hair cycle is a well-controlled process involving stem cell proliferation and quiescence. Hair bulge is a ...

Lectin-based Isolation and Culture of Mouse Embryonic Motoneurons

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

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

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

Isolation and Culture of Rat Embryonic Neural Cells: A Quick Protocol

We are describing a quick method to dissociate and culture hippocampal or cortical neurons from E15-17 rat embryos. The procedure can be applied successfully to the isolation of mouse and human primary neurons and neural progenitors. Dissociated neurons are maintained in serum-free medium up to several weeks. These cultures can be used for nucleofection, immunocytochemistry, nucleic acids preparation, as well as electrophysiology. Older neuronal cultures can also be transfected with a good efficiency rate by lentiviral transduction and, less efficiently, with calcium phosphate or lipid-based methods such as lipofectamine.

We describe a rapid methodology to isolate and culture hippocampal and cortical neurons from rodent embryos. This protocol allows us to perform experiments in which nearly pure neuronal cultures are required.

We are describing a quick method to dissociate and culture hippocampal or cortical neurons from E15-17 rat embryos. The procedure can be applied ...

Expansion of Embryonic and Adult Neural Stem Cells by In Utero Electroporation or Viral Stereotaxic Injection

Somatic stem cells can divide to generate additional stem cells (expansion) or more differentiated cell types (differentiation), which is fundamental for tissue formation during embryonic development and tissue homeostasis during adulthood 1. Currently, great efforts are invested towards controlling the switch of somatic stem cells from expansion to differentiation because this is thought to be fundamental for developing novel strategies for regenerative medicine 1,2. However, a major challenge in the study and use of somatic stem cell is that their expansion has been proven very difficult to control.
Here we describe a system that allows the control of neural stem/progenitor cell (altogether referred to as NSC) expansion in the mouse embryonic cortex or the adult hippocampus by manipulating the expression of the cdk4/cyclinD1 complex, a major regulator of the G1 phase of the cell cycle and somatic stem cell differentiation 3,4. Specifically, two different approaches are described by which the cdk4/cyclinD1 complex is overexpressed in NSC in vivo. By the first approach, overexpression of the cell cycle regulators is obtained by injecting plasmids encoding for cdk4/cyclinD1 in the lumen of the mouse telencephalon followed by in utero electroporation to deliver them to NSC of the lateral cortex, thus, triggering episomal expression of the transgenes 5-8. By the second approach, highly concentrated HIV-derived viruses are stereotaxically injected in the dentate gyrus of the adult mouse hippocampus, thus, triggering constitutive expression of the cell cycle regulators after integration of the viral construct in the genome of infected cells 9. Both approaches, whose basic principles were already described by other video protocols 10-14, were here optimized to i) reduce tissue damage, ii) target wide portions of very specific brain regions, iii) obtain high numbers of manipulated cells within each region, and iv) trigger high expression levels of the transgenes within each cell. Transient overexpression of the transgenes using the two approaches is obtained by different means i.e. by natural dilution of the electroporated plasmids due to cell division or tamoxifen administration in Cre-expressing NSC infected with viruses carrying cdk4/cyclinD1 flanked by loxP sites, respectively 9,15.
These methods provide a very powerful platform to acutely and tissue-specifically manipulate the expression of any gene in the mouse brain. In particular, by manipulating the expression of the cdk4/cyclinD1 complex, our system allows the temporal control of NSC expansion and their switch to differentiation, thus, ultimately increasing the number of neurons generated in the mammalian brain. Our approach may be critically important for basic research and using somatic stem cells for therapy of the mammalian central nervous system while providing a better understanding of i) stem cell contribution to tissue formation during development, ii) tissue homeostasis during adulthood, iii) the role of adult neurogenesis in cognitive functions, and perhaps, iv) better using somatic stem cells in models of neurodegenerative diseases.

Expansion of Embryonic and Adult Neural Stem Cells by In Utero Electroporation or Viral Stereotaxic Injection

Controlling the expansion of somatic stem cells is a major factor hampering their study and use in therapy. Here we describe a system to temporally control neural stem cells expansion during development and adulthood, which can be used to increase the number of neurons generated in the mouse brain.

Somatic stem cells can divide to generate additional stem cells (expansion) or more differentiated cell types (differentiation), which is fundamental for ...

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 ...

Isolation and Culture of Endothelial Cells from the Embryonic Forebrain

Embryonic brain endothelial cells can serve as an important tool in the study of angiogenesis and neurovascular development and interactions. The two vascular networks of the embryonic forebrain, pial and periventricular, are spatially distinctive and have different origins and growth patterns. Endothelial cells from the pial and periventricular vascular networks have unique gene expression profiles and functions. Here we present a step-by-step protocol for isolation, culture, and verification of pure populations of endothelial cells from the periventricular vascular network (PVECs) of the embryonic forebrain (telencephalon). In this approach, telencephalon devoid of pial membrane obtained from embryonic day 15 mice is minced, digested with collagenase/dispase, and dispersed mechanically into a single cell suspension. PVECs are purified from cell suspension using positive selection with anti-CD-31/PECAM-1 antibody conjugated to MicroBeads using a strong magnetic separation method. Purified cells are cultured on collagen 1&#160;coated culture dishes in endothelial cell culture medium until they become confluent and further subcultured. PVECs obtained with this protocol exhibit cobblestone and spindle shaped phenotypes, as visualized by phase-contrast light microscopy and fluorescence microscopy. Purity of PVEC cultures was established with endothelial cell markers. In our hands, this method reliably and consistently yields pure populations of PVECs. This protocol will benefit studies aimed at gaining mechanistic insights into forebrain angiogenesis, understanding PVEC interactions, and cross-talks with neuronal cell types and holds tremendous potential for therapeutic angiogenesis.

This video demonstrates an easy and reliable strategy for preparation of pure cultures of endothelial cells from the embryonic forebrain within 10-12 days and will be useful for research focused on many aspects of cerebral angiogenesis.

Embryonic brain endothelial cells can serve as an important tool in the study of angiogenesis and neurovascular development and interactions. The two ...

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 ...