Name: preparation of rat oligodendrocyte progenitor cultures and quantification of oligodendrogenesis using dual-infrared fluorescence scanning
Uploaded: 2016-02-17T15:00:00
Description: Watch this Scientific Journal Video about Preparation of Rat Oligodendrocyte Progenitor Cultures and Quantification of Oligodendrogenesis Using Dual-infrared Fluorescence Scanning at JoVE.com

Grant sponsor: National Institutes of Health; Grant number: R37 NS041435.

Procedures involving animal subjects have been approved by Institutional Animal Care and Use Committee (IACUC) and Johns Hopkins School of Medicine.
1. Preparation of Assay Plates, Stock Solutions, and OPC Base Media
Note: The rat OPC base (Sato) media described here has been derived from previously published studies12,13. Alternative media formulations may also be compatible with this procedure.
<ol>
	<li>Resuspend poly-L-lysine (PLL) to a concentration of 10 &#181;g/ml in sterile deionized wa...

<ol>
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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=Hydrocortisone+stimulates+the+development+of+oligodendrocytes+in+primary+glial+cultures+and+affects+glucose+metabolism+and+lipid+synthesis+in+these+cultures.">Hydrocortisone stimulates the development of oligodendrocytes in primary glial cultures and affects glucose metabolism and lipid synthesis in these cultures.</a> Brain Res. 431 (1), 79-86 (1987).</li><li>Tosic, M., Torch, S., Comte, V., Dolivo, M., Honegger, P., Matthieu, J. 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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=A+regenerative+approach+to+the+treatment+of+multiple+sclerosis.">A regenerative approach to the treatment of multiple sclerosis.</a> Nature. 502 (7471), 327-332 (2013).</li><li>Najm, F. 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=Drug-based+modulation+of+endogenous+stem+cells+promotes+functional+remyelination+in+vivo.">Drug-based modulation of endogenous stem cells promotes functional remyelination in vivo.</a> Nature. 522 (7555), 216-220 (2015).</li><li>Zhang, S. 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The protocol presented here describes a fast and reliable method for isolating rat OPCs and quantifying in vitro oligodendrogenesis in response to experimental factors. Using positive selection, high yields of viable and pure OPCs are used directly for experimental purposes. This method streamlines the isolation, culturing, and differentiation steps into a 1 week time frame, and fixed cells can be conveniently stored at 4 &#176;C for several weeks without any loss in assay sensitivity.
<p class="jove_content...

Efficient nerve conduction in the mammalian central nervous system (CNS) requires myelination of axons by oligodendrocytes. During development, oligodendrocytes arise from a pool of oligodendrocyte progenitor cells (OPCs) that are thought to migrate from the ventricular zones of the developing forebrain and neural tube1. After migration OPCs differentiate into mature, myelinating oligodendrocytes that not only facilitate efficient impulse propagation, but also provide axons with trophic support2. The adult CNS maintains an abundant population of OPCs that are dispersed throughout the gray and white matter comprising approximately 5-8% of all cells3. Following a demyelinating insult, OPCs migrate to the site of injury, proliferate, and differentiate to replace lost or damaged myelin sheaths on exposed axons. However, in some disease/injury settings, this process is found to be inefficient or can fail completely4. While chronic demyelination is thought to add to the burden of disease, efficient oligodendrogenesis and remyelination may alleviate symptoms5. It has therefore been of interest to study OPCs in vitro to determine the effect of experimental factors on oligodendrogenesis.
Insight into the different phases of oligodendrocyte differentiation has been made possible by the identification of stage specific cell markers. Self-renewing early progenitor cells are defined by their expression of platelet derived growth factor receptor alpha (PDGFR&#945;), neural/glia antigen 2 (NG2) and A2B56-8. As OPCs initiate their differentiation program and withdraw from the cell cycle, they downregulate expression of these markers and begin to express proteins indicative of premyelinating oligodendrocytes including Cyclic-nucleotide 3&#39;-phosphodiesterase (CNPase) and O4. Finally, their differentiation into more mature oligodendrocytes is characterized by the expression of myelin-associated proteins, including myelin-associated glycoprotein (MAG), proteolipid protein (PLP), and myelin basic protein (MBP). MBP is an intracellular peripheral membrane protein and a major component of the myelin sheath. Mice lacking MBP develop a severe phenotype in which CNS myelination is significantly decreased leading to tremors, convulsions and early death9,10. This important role of MBP in myelination has led to its use as a marker of oligodendrocyte differentiation both in vitro and in vivo11.
Quantification of MBP can be achieved using several different methodologies. RT-PCR and Western blot analysis allow for quantification of MBP levels under different treatment regimens. Immunocytochemistry is a common qualitative approach that can also be quantitative when camera-based microscopy approaches are used. Although these systems are reliable and fundamental to the study of oligodendrocyte differentiation, they each have their own disadvantages that limit their use in drug screening. First, the amount of primary OPCs that are needed for RT-PCR and Western blot analysis reduces the number of variables that can be examined simultaneously. While the cell requirement for immunocytochemistry is much lower, substantial time must be devoted to each experiment if quantification is the goal. Numerous images must be captured and then quantified to facilitate experimental analysis. These caveats become important obstacles to consider for studies that require high throughput assessment. Here we describe a method that utilizes fundamental aspects from both the immunocytochemistry and Western blot methodologies for myelin quantification, while significantly reducing both the number of cells required and time to complete quantitative analysis.

<table border="0" cellpadding="0" cellspacing="0" width="691">
	<tbody>
		<tr height="20">
			<td colspan="4" height="20" style="height:20px;width:691px;">Dissection Materials</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">PBS without Ca2+ and Mg2+</td>
			<td>Mediatech</td>
			<td>21-040-CV</td>
			<td>1 x</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">10 cm Polystyrene Petri Dishes</td>
			<td>Fisherbrand</td>
			<td>0857512</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Light Dissection Microscope</td>
			<td>Motic</td>
			<td>SM2-168</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;"></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td colspan="4" height="21" style="height:21px;">Dissociation Materials</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Tube Rotator</td>
			<td>Miltenyi Biotec</td>
			<td>130-090-753</td>
			<td>Dissociation Tube Rotator</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Neural Tissue Dissociation Kit (P)</td>
			<td>Miltenyi Biotec</td>
			<td>130-092-628</td>
			<td>Enzymatic Dissociation Kit</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PBS with Ca2+ and Mg2+</td>
			<td>Corning</td>
			<td>20-030-CV</td>
			<td>1 x</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">40 &#956;m Cell Strainer</td>
			<td>Corning</td>
			<td>352340</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;"></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td colspan="4" height="21" style="height:21px;">A2B5 Column Purification&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Anti-A2B5 Microbeads</td>
			<td>Miltenyi Biotec</td>
			<td>130-097-864</td>
			<td>Bead Bound A2B5 Antibody</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">LS Columns</td>
			<td>Miltenyi Biotec</td>
			<td>130-042-401</td>
			<td>Magnetic Selection Columns</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">EDTA</td>
			<td>Corning</td>
			<td>46-034-Cl</td>
			<td>2mM</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PBS with Ca2+ and Mg2+</td>
			<td>Corning</td>
			<td>20-030-CV</td>
			<td>1 x</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bovine Serum Albumin&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>A9647</td>
			<td>0.50%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;"></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Culture Materials</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PDGF-AA</td>
			<td>PeproTech Inc</td>
			<td>100-13A</td>
			<td>20 ng/mL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dimethyl sulfoxide</td>
			<td>Sigma-Aldrich</td>
			<td>D2650</td>
			<td>Hybri-Max 100 mL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Triiodothyronine&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>T6397</td>
			<td>45 nM</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Clemastine fumarate salt</td>
			<td>Sigma-Aldrich</td>
			<td>SML0445-100MG</td>
			<td>1 &#956;M</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Quetiapine hemifumarate salt</td>
			<td>Sigma-Aldrich</td>
			<td>Q3638-10MG</td>
			<td>1 &#956;M</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">N-acetyl cysteine</td>
			<td>Sigma-Aldrich</td>
			<td>A9165</td>
			<td>5 &#956;g/mL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Progesterone</td>
			<td>Sigma-Aldrich</td>
			<td>P8783</td>
			<td>60 ng/mL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Poly-L-lysine</td>
			<td>Sigma-Aldrich</td>
			<td>P1524</td>
			<td>10 &#956;g/mL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Putrecine</td>
			<td>Sigma-Aldrich</td>
			<td>P7505</td>
			<td>16 &#956;g/mL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium Selenite</td>
			<td>Sigma-Aldrich</td>
			<td>S5261</td>
			<td>40 ng/mL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hydrocortisone</td>
			<td>Sigma-Aldrich</td>
			<td>H0135</td>
			<td>50 ng/mL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">d-Biotin</td>
			<td>Sigma-Aldrich</td>
			<td>B4639</td>
			<td>10 ng/mL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Insulin</td>
			<td>Sigma-Aldrich</td>
			<td>I6634</td>
			<td>5 &#956;g/mL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Apo-Transferrin</td>
			<td>Sigma-Aldrich</td>
			<td>T1147</td>
			<td>100 &#956;g/mL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bovine Serum Albumin</td>
			<td>Sigma-Aldrich</td>
			<td>A4161</td>
			<td>100 &#956;g/mL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Trace Elements B</td>
			<td>Corning</td>
			<td>25-022-Cl</td>
			<td>1 x&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">B-27 Supplement</td>
			<td>Life Technologies</td>
			<td>17504044</td>
			<td>1 x&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Penicillin/Streptomycin</td>
			<td>Life Technologies</td>
			<td>15140122</td>
			<td>1 x&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">DMEM</td>
			<td>Life Technologies</td>
			<td>11995-065</td>
			<td>1 x&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">24-well Black Visiplate with lid</td>
			<td>Perkin Elmer</td>
			<td>1450-605</td>
			<td>Tissue culture grade</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;"></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td colspan="4" height="21" style="height:21px;">Immunocytochemistry and Quantification</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PFA</td>
			<td>Sigma-Aldrich</td>
			<td>100-13A</td>
			<td>4%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Triton X-100</td>
			<td>Sigma-Aldrich</td>
			<td>78787</td>
			<td>0.10%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Normal Goat Serum</td>
			<td>Jackson Immuno Research</td>
			<td>005-000-121</td>
			<td>5%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">mouse monoclonal anti-MBP</td>
			<td>Biolegend</td>
			<td>SMI-99P</td>
			<td>1:1000 Dilution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">rabbit polyclonal anti-Actin</td>
			<td>Santa Cruz Biotecnology</td>
			<td>SC-7210</td>
			<td>1:200 Dilution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">rabbit polyclonal anti-Olig2</td>
			<td>Millipore</td>
			<td>AB9610</td>
			<td>1:1000 Dilution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">goat anti-mouse 680RD</td>
			<td>Licor</td>
			<td>926-68070</td>
			<td>1:500 Dilution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">goat anti-rabbit 800CW</td>
			<td>Licor</td>
			<td>926-32211</td>
			<td>1:500 Dilution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Alexa Fluor 594 goat anti-mouse</td>
			<td>Life Technologies</td>
			<td>A11032</td>
			<td>1:000 dilution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Alexa Fluor 488 goat anti-rabbit</td>
			<td>Life Technologies</td>
			<td>A11008</td>
			<td>1:000 dilution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Prolong Gold antifade with DAPI</td>
			<td>Life Technologies</td>
			<td>P36931</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">DPBS with Ca2+ and Mg2+</td>
			<td>Corning</td>
			<td>21-030-CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Licor Odyssey Clx Infared Imaging System</td>
			<td>Licor</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

preparation of rat oligodendrocyte progenitor cultures and quantification of oligodendrogenesis using dual-infrared fluorescence scanning

Efficient oligodendrogenesis is the therapeutic goal of a number of areas of research including spinal cord injury, neonatal hypoxia, and demyelinating diseases such as multiple sclerosis and transverse myelitis. Myelination is required to not only facilitate rapid impulse propagation within the central nervous system, but also to provide trophic support to underlying axons. Oligodendrocyte progenitor cells (OPCs) can be studied in vitro to help identify factors that may promote or inhibit oligodendrocyte differentiation. To date, many of the methods available to evaluate this process have either required large numbers of cells, thus limiting the number of conditions that can be investigated at any one time, or labor-intensive methods of quantification. Herein, we describe a protocol for the isolation of large numbers of highly pure OPCs together with a fast and reliable method to determine oligodendrogenesis from multiple conditions simultaneously. OPCs are isolated from P5-P7 neonatal rat cortices and grown in vitro for three days prior to differentiation. Four days after differentiation, oligodendrogenesis is evaluated using a dual-infrared fluorescence-scanning assay to determine expression of the myelin protein.

A2B5-positive OPCs are isolated through positive cell selection using a magnetic column separation system. Prior to the isolation procedure, the whole brain is removed from rat pups that are between P5 and P7. Once the whole brain is successfully detached from the skull, the olfactory bulbs and cerebellum are removed using fine surgical forceps (Figure 1A). In order to isolate cerebral cortical tissue the hypothalamus, thalamus and midbrain are excised by careful dissecti...

Watch this Scientific Journal Video about Preparation of Rat Oligodendrocyte Progenitor Cultures and Quantification of Oligodendrogenesis Using Dual-infrared Fluorescence Scanning at JoVE.com

Preparation of Rat Oligodendrocyte Progenitor Cultures and Quantification of Oligodendrogenesis Using Dual-infrared Fluorescence Scanning

Oligodendrocytes are the myelinating cells of the central nervous system. This protocol describes a method for the isolation and culture of their precursors, oligodendrocyte progenitor cells, from rat cortices, as well as a fast and reliable quantitative method to evaluate oligodendrogenesis in vitro in response to experimental factors.

Efficient oligodendrogenesis is the therapeutic goal of a number of areas of research including spinal cord injury, neonatal hypoxia, and demyelinating ...

The overall goal of this procedure is to isolate and culture rat oligodendrocyte progenitor cells and quantify the oligodendrogenesis in response to experimental factors. Efficient oligodendrogenesis is the therapeutic goal in numerous areas of research, including spinal cord injury, neonatal hypoxia, and demyelinating diseases such as transverse myelitis and multiple sclerosis. The main advantage of this technique is that it combines a protocol for the isolation of large numbers of OPCs with a fast and reliable method to determine oligodendrogenesis across multiple experimental conditions simultaneously.To begin this procedure, sterilize all the dissection equipment using a heated bead sterilizer. Then, add 15 to 20 milliliters of PBS to a 50 milliliter conical tube. Place the conical tube on ice, and use it to hold the diced cortex tissue during dissection.Next, add cold PBS to a 10 centimeter Petri dish which will be used for dissection under the light microscope. After sacrificing the rat pups, cut the skin behind the ears along the midline using small scissors. And peel the skin flaps back.Next, cut the cranium along the midline from the brain stem to the eyes. And be careful not to cut too deep in order to preserve the structure of the underlying cortex. After that, make two lateral cuts inferior to the cerebellum by inserting small surgical scissors into the foramen magnum.Make an additional cut between the eyes anterior to the olfactory bulbs. Carefully peel each half of the cranium back. Remove the whole brain and place it in a 10 centimeter Petri dish filled with cold PBS.Under a dissection light microscope, remove the olfactory bulbs and cerebellum with fine surgical forceps. Flip the brain so that the ventral surface is visible. Then, using fine straight forceps, perform a blunt dissection by placing closed forceps tips between the cortex and hypothalamus to a depth of about two-thirds of the brain.Open the forceps once they are in place, then repeat the procedure for the other hemisphere. After that, tease the cortex from the hypothalamus and midbrain regions. Remove the hypothalamus, thalamus, and midbrain by holding the midbrain at its posterior surface and peeling it toward the anterior end of the brain.Subsequently, sever the anterior connections. Using fine bent dissection forceps, remove the hippocampus and sever it's connection to the cortex. Then, remove the remaining striatum by scraping it from the underlying cortex in an outward diagonal motion.Clear the blood vessels and meninges from the ventral surface of the cortex. Next, flip the brain so that the dorsal surface is visible. Peel the meninges from the underlying cortex where the olfactory bulb is located.Repeat the procedures for a total of three to four rat pups. And place all the dissected cortices into a Petri dish. Chop them with a sterilized razor blade until one millimeter by one millimeter chunks are achieved.Then collect the tissues by rinsing the dish with PBS before placing it back on ice. Now, using a glass Pasteur pipette attached to a pipette controller, mechanically dissociate the tissue by pipetting ten to fifteen times or until the tissue pieces are reduced in size and the solution has become cloudy. Next, return the sample to the 37 degree Celsius tissue culture incubator for 15 minutes with continuous rotation.After that, add 10 milliliters of PBS to each sample and filter the homogenate through a 40 micrometer pore filter placed over a 50 milliliter tube. Then, rinse the filter with an additional one to two milliliters of PBS. Pool all the homogenate samples into one 50 milliliter conical tube and acquire an overall cell count.After performing the cell count, split the homogenate evenly into the 15 millileter conical tubes, and centrifuge them for 10 to 12 minutes at 300 gs. Prime each LS column by adding five milliliters of column buffer. And collect the flow through a 15 milliliter conical tube.Once the column buffer has completely passed through the upper chamber, apply 1000 microliters of the cell suspension to each column and allow the cells to run through by gravity. Next, remove each column and place it into a 15 milliliter conical tube. Add five milliliters of column buffer and plunge the buffer though the column at a fast rate to dislodge the bound cells and release them from the column.To plate the cells, dilute them with OPC proliferation media to 60, 000 cells per milliliter. Pipette 500 microliters of cells along the side of each black, clear bottom well of a 24 well plate. Mix the cells by shaking the plate horizontally, using a figure eight motion.In this procedure, place a 200 microliter pipette tip over a glass Pasteur pipette to ensure that the well is not damaged during aspiration. Then, aspirate the media from the culture wells one treatment group at a time to avoid drying the cells. After that, slowly add 500 microliters of treatment master mix along the side of the well using a one milliliter pipette.Incubate the cultures and perform a full media exchange with fresh treatment media every two to three days. At the end of the desired treatment period, aspirate the media. Slowly add 400 microliters of PFA to the side of the well to fix the cells.And incubate the plate for 20 minutes at room temperature. After 20 minutes, aspirate PFA and slowly add 500 microliters of sterile D-PBS to wash the cells. Repeat the wash two more times and do not aspirate the final wash.Now, bring the plate to room temperature, aspirate the wells, and add 250 microliters of D-PBS containing five percent NGS and 0.1 percent Triton x-100. Incubate the plate at room temperature for one hour with gentle orbital shaking. Prepare the primary incubation solution by diluting mouse monoclonal anti MBP antibody and rabbit polyclonal anti olig2 antibody in D-PBS containing five percent NGS.Then, incubate the primary antibodies at four degrees Celsius overnight for 16 to 18 hours with gentle orbital shaking. While washing the plate, prepare the secondary incubation solution by diluting the anti mouse 680, and anti rabbit 800 antibodies in D-PBS containing five percent NGS. Next, aspirate the final wash and add 250 microliters of secondary incubation solution.Protect the plate from light and incubate it at room temperature for one hour with gentle orbital shaking. After that, scan the plate using an imaging system capable of detecting 700 nanometer and 800 nanometer fluorescence emissions. As a starting point, set the focal offset to three, and sensitivities to one point five for MBP, five point zero for actin, and three point five for olig2.Adjust the sensitivity values as needed to avoid signal overexposure. In this schematic, the DIFS assay begins with freshly isolated A2B5 positive rat OPCs plated on PLL coded culture vessels. These cultures are proliferated for three days in the presence of 20 nanograms per milliliter PDGFAA, and then treated with experimental factors in fresh PDGF-free media on day zero.Treatment media is fully replenished on day two. And the cells are fixed with 4 percent paraformaldehyde on day four. Here, immunocytochemistry for olig2 and MBP was performed on the representative cultures on day zero and day four using Dapi as a nuclear counter stain.These cultures exhibit constitutive staining for the pan oligodendrocyte lineage cell marker, Olig2, on days zero and four. Whereas staining for mature oligodendrocyte marker MBP was only evident by day four. After watching this video you should have a good understanding of how to purify, culture and differentiate A2B5 positive rat OPCs in order to quantify the effect of experimental factors on oligodendrogenesis.The identification of factors that promote oligodenrogenesis is of particular relevance to the study of demyelinating diseases such as multiple sclerosis. Once mastered, the techniques described here may help to identify such factors and ultimately develop better therapeutics.

preparation-rat-oligodendrocyte-progenitor-cultures-quantification

Research

JoVE Journal

Developmental Biology

Organotypic Slice Cultures for Studies of Postnatal Neurogenesis

Here we describe a technique for studying hippocampal postnatal neurogenesis in the rodent brain using the organotypic slice culture technique. This method maintains the characteristic topographical morphology of the hippocampus while allowing direct application of pharmacological agents to the developing hippocampal dentate gyrus. Additionally, slice cultures can be maintained for up to 4 weeks and thus, allow one to study the maturation process of newborn granule neurons. Slice cultures allow for efficient pharmacological manipulation of hippocampal slices while excluding complex variables such as uncertainties related to the deep anatomic location of the hippocampus as well as the blood brain barrier. For these reasons, we sought to optimize organotypic slice cultures specifically for postnatal neurogenesis research.

Here we describe a technique for studying hippocampal postnatal neurogenesis using the organotypic slice culture technique. This method allows for in vitro manipulation of adult neurogenesis and allows for the direct application of pharmacological agents to the cultured hippocampus.

Here we describe a technique for studying hippocampal postnatal neurogenesis in the rodent brain using the organotypic slice culture technique. This ...

Delivery of In Vivo Acute Intermittent Hypoxia in Neonatal Rodents to Prime Subventricular Zone-derived Neural Progenitor Cell Cultures

Extended culture of neural stem/progenitor cells facilitates in vitro analyses to understand their biology while enabling expansion of cell populations to adequate numbers prior to transplantation. Identifying approaches to refine this process, to augment the production of all CNS cell types (i.e., neurons), and to possibly contribute to therapeutic cell therapy protocols is a high research priority. This report describes an easily applied in vivo &#8220;pre-conditioning&#8221; stimulus which can be delivered to awake, non-anesthetized animals. Thus, it is a non-invasive and non-stressful procedure. Specifically described are the procedures for exposing mouse or rat pups (aged postnatal day 1-8) to a brief (40-80 min) period of intermittent hypoxia (AIH). The procedures included in this video protocol include calibration of the whole-body plethysmography chamber in which pups are placed during AIH and the technical details of AIH exposure. The efficacy of this approach to elicit tissue-level changes in the awake animal is demonstrated through the enhancement of subsequent in vitro expansion and neuronal differentiation in cells harvested from the subventricular zone (SVZ). These results support the notion that tissue level changes across multiple systems could be observed following AIH, and support the continued optimization and establishment of AIH as a priming or conditioning modality for therapeutic cell populations.

Delivery of In Vivo Acute Intermittent Hypoxia in Neonatal Rodents to Prime Subventricular Zone-derived Neural Progenitor Cell Cultures

This article describes the methodology for administering short periods of intermittent hypoxia to postnatal day 1-8 mouse or rat pups. This approach effectively elicits a robust tissue level &#8220;priming effect&#8221; on cultured neural progenitor cells that are harvested within 30 min of hypoxia exposure.

Extended culture of neural stem/progenitor cells facilitates in vitro analyses to understand their biology while enabling expansion of cell populations to ...

Isolation of Neural Stem/Progenitor Cells from the Periventricular Region of the Adult Rat and Human Spinal Cord

Adult rat and human spinal cord neural stem/progenitor cells (NSPCs) cultured in growth factor-enriched medium allows for the proliferation of multipotent, self-renewing, and expandable neural stem cells. In serum conditions, these multipotent NSPCs will differentiate, generating neurons, astrocytes, and oligodendrocytes. The harvested tissue is enzymatically dissociated in a papain-EDTA solution and then mechanically dissociated and separated through a discontinuous density gradient to yield a single cell suspension which is plated in neurobasal medium supplemented with epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), and heparin. Adult rat spinal cord NSPCs are cultured as free-floating neurospheres and adult human spinal cord NSPCs are grown as adherent cultures. Under these conditions, adult spinal cord NSPCs proliferate, express markers of precursor cells, and can be continuously expanded upon passage. These cells can be studied in vitro in response to various stimuli, and exogenous factors may be used to promote lineage restriction to examine neural stem cell differentiation. Multipotent NSPCs or their progeny can also be transplanted into various animal models to assess regenerative repair.

The adult mammalian spinal cord contains neural stem/progenitor cells (NSPCs) that can be isolated and expanded in culture. This protocol describes the harvesting, isolation, culture, and passaging of NSPCs generated from the periventricular region of the adult spinal cord from the rat and from human organ transplant donors.

Adult rat and human spinal cord neural stem/progenitor cells (NSPCs) cultured in growth factor-enriched medium allows for the proliferation of ...

Generation of Genetically Modified Organotypic Skin Cultures Using Devitalized Human Dermis

Organotypic cultures allow the reconstitution of a 3D environment critical for cell-cell contact and cell-matrix interactions which mimics the function and physiology of their in vivo tissue counterparts. This is exemplified by organotypic skin cultures which faithfully recapitulates the epidermal differentiation and stratification program. Primary human epidermal keratinocytes are genetically manipulable through retroviruses where genes can be easily overexpressed or knocked down. These genetically modified keratinocytes can then be used to regenerate human epidermis in organotypic skin cultures providing a powerful model to study genetic pathways impacting epidermal growth, differentiation, and disease progression. The protocols presented here describe methods to prepare devitalized human dermis as well as to genetically manipulate primary human keratinocytes in order to generate organotypic skin cultures. Regenerated human skin can be used in downstream applications such as gene expression profiling, immunostaining, and chromatin immunoprecipitations followed by high throughput sequencing. Thus, generation of these genetically modified organotypic skin cultures will allow the determination of genes that are critical for maintaining skin homeostasis.

The goal of this paper is to provide a comprehensive and detailed protocol on how to generate genetically modified human organotypic skin from epidermal keratinocytes and devitalized human dermis.

Organotypic cultures allow the reconstitution of a 3D environment critical for cell-cell contact and cell-matrix interactions which mimics the function ...

Using Light Sheet Fluorescence Microscopy to Image Zebrafish Eye Development

Light sheet fluorescence microscopy (LSFM) is gaining more and more popularity as a method to image embryonic development. The main advantages of LSFM compared to confocal systems are its low phototoxicity, gentle mounting strategies, fast acquisition with high signal to noise ratio and the possibility of imaging samples from various angles (views) for long periods of time. Imaging from multiple views unleashes the full potential of LSFM, but at the same time it can create terabyte-sized datasets. Processing such datasets is the biggest challenge of using LSFM. In this protocol we outline some solutions to this problem. Until recently, LSFM was mostly performed in laboratories that had the expertise to build and operate their own light sheet microscopes. However, in the last three years several commercial implementations of LSFM became available, which are multipurpose and easy to use for any developmental biologist. This article is primarily directed to those researchers, who are not LSFM technology developers, but want to employ LSFM as a tool to answer specific developmental biology questions. 
Here, we use imaging of zebrafish eye development as an example to introduce the reader to LSFM technology and we demonstrate applications of LSFM across multiple spatial and temporal scales. This article describes a complete experimental protocol starting with the mounting of zebrafish embryos for LSFM. We then outline the options for imaging using the commercially available light sheet microscope. Importantly, we also explain a pipeline for subsequent registration and fusion of multiview datasets using an open source solution implemented as a Fiji plugin. While this protocol focuses on imaging the developing zebrafish eye and processing data from a particular imaging setup, most of the insights and troubleshooting suggestions presented here are of general use and the protocol can be adapted to a variety of light sheet microscopy experiments.

Light sheet fluorescence microscopy is an excellent tool for imaging embryonic development. It allows recording of long time-lapse movies of live embryos in near physiological conditions. We demonstrate its application for imaging zebrafish eye development across wide spatio-temporal scales and present a pipeline for fusion and deconvolution of multiview datasets.

Light sheet fluorescence microscopy (LSFM) is gaining more and more popularity as a method to image embryonic development. The main advantages of LSFM ...

Using Primary Neurosphere Cultures to Study Primary Cilia

The primary cilium is fundamentally important for the proliferation of neural stem/progenitor cells and for neuronal differentiation during embryonic, postnatal, and adult life. In addition, most differentiated neurons possess primary cilia that house signaling receptors, such as G-protein-coupled receptors, and signaling molecules, such as adenylyl cyclases. The primary cilium determines the activity of multiple developmental pathways, including the sonic hedgehog pathway during embryonic neuronal development, and also functions in promoting compartmentalized subcellular signaling during adult neuronal function. Unsurprisingly, defects in primary cilium biogenesis and function have been linked to developmental anomalies of the brain, central obesity, and learning and memory deficits. Thus, it is imperative to study primary cilium biogenesis and ciliary trafficking in the context of neural stem/progenitor cells and differentiated neurons. However, culturing methods for primary neurons require considerable expertise and are not amenable to freeze-thaw cycles. In this protocol, we discuss culturing methods for mixed populations of neural stem/progenitor cells using primary neurospheres. The neurosphere-based culturing methods provide the combined benefits of studying primary neural stem/progenitor cells: amenability to multiple passages and freeze-thaw cycles, differentiation potential into neurons/glia, and transfectability. Importantly, we determined that neurosphere-derived neural stem/progenitor cells and differentiated neurons are ciliated in culture and localize signaling molecules relevant to ciliary function in these compartments. Utilizing these cultures, we further describe methods to study ciliogenesis and ciliary trafficking in neural stem/progenitor cells and differentiated neurons. These neurosphere-based methods allow us to study cilia-regulated cellular pathways, including G-protein-coupled receptor and sonic hedgehog signaling, in the context of neural stem/progenitor cells and differentiated neurons.

The primary cilium is fundamentally important in neural progenitor cell proliferation, neuronal differentiation, and adult neuronal function. Here, we describe a method to study ciliogenesis and the trafficking of signaling proteins to cilia in neural stem/progenitor cells and differentiated neurons using primary neurosphere cultures.

The primary cilium is fundamentally important for the proliferation of neural stem/progenitor cells and for neuronal differentiation during embryonic, ...

Single-Cell Quantification of Protein Degradation Rates by Time-Lapse Fluorescence Microscopy in Adherent Cell Culture

Proteins are in a dynamic state of synthesis and degradation and their half-lives can be adjusted under various circumstances. However, most commonly used approaches to determine protein half-life are either limited to population averages from lysed cells or require the use of protein synthesis inhibitors. This protocol describes a method to measure protein half-lives in single living adherent cells, using SNAP-tag fusion proteins in combination with fluorescence time-lapse microscopy. Any protein of interest fused to a SNAP-tag can be covalently bound by a fluorescent, cell permeable dye that is coupled to a benzylguanine derivative, and the decay of the labeled protein population can be monitored after washout of the residual dye. Subsequent cell tracking and quantification of the integrated fluorescence intensity over time results in an exponential decay curve for each tracked cell, allowing for determining protein degradation rates in single cells by curve fitting. This method provides an estimate for the heterogeneity of half-lives in a population of cultured cells, which cannot easily be assessed by other methods. The approach presented here is applicable to any type of cultured adherent cells expressing a protein of interest fused to a SNAP-tag. Here we use mouse embryonic stem (ES) cells grown on E-cadherin-coated cell culture plates to illustrate how single cell degradation rates of proteins with a broad range of half-lives can be determined.

This protocol describes a method to determine protein half-lives in single living adherent cells, using pulse labeling and fluorescence time-lapse imaging of SNAP-tag fusion proteins.

Proteins are in a dynamic state of synthesis and degradation and their half-lives can be adjusted under various circumstances. However, most commonly used ...

Visualizing the Node and Notochordal Plate In Gastrulating Mouse Embryos Using Scanning Electron Microscopy and Whole Mount Immunofluorescence

The post-implantation mouse embryo undergoes major shape changes after the initiation of gastrulation and morphogenesis. A hallmark of morphogenesis is the formation of the transient organizers, the node and notochordal plate, from cells that have passed through the primitive streak. The proper formation of these signaling centers is essential for the development of the body plan and techniques to visualize them are of high interest to mouse developmental biologists. The node and notochordal plate lie on the ventral surface of gastrulating mouse embryos around embryonic day (E) 7.5 of development. The node is a cup-shaped structure whose cells possess a single slender cilium each. The proper subcellular localization and rotation of the cilia in the node pit determines left-right asymmetry. The notochordal plate cells also possess single cilia albeit shorter than those of the node cells. The notochordal plate forms the notochord which acts as an important signaling organizer for somitogenesis and neural patterning. Because the cells of the node and notochordal plate are transiently present on the surface and possess cilia, they can be visualized using scanning electron microscopy (SEM). Among other techniques used to visualize these structures at the cellular level is whole mount immunofluorescence (WMIF) using the antibodies against the proteins that are highly expressed in the node and notochordal plate. In this report, we describe our optimized protocols to perform SEM and WMIF of the node and notochordal plate in developing mouse embryos to help in the assessment of tissue shape and cellular organization in wild-type and gastrulation mutant embryos.

The node and notochordal plate are transient signaling organizers in developing mouse embryos that can be visualized using several techniques. Here, we describe in detail how to perform two of the techniques to study their structure and morphogenesis: 1) scanning electron microscopy (SEM); and 2) whole mount immunofluorescence (WMIF).

The post-implantation mouse embryo undergoes major shape changes after the initiation of gastrulation and morphogenesis. A hallmark of morphogenesis is ...

Three-dimensional Angiogenesis Assay System using Co-culture Spheroids Formed by Endothelial Colony Forming Cells and Mesenchymal Stem Cells

Studies in the field of angiogenesis have been aggressively growing in the last few decades with the recognition that angiogenesis is a hallmark of more than 50 different pathological conditions, such as rheumatoid arthritis, oculopathy, cardiovascular diseases, and tumor metastasis. During angiogenesis drug development, it is crucial to use in vitro assay systems with appropriate cell types and proper conditions to reflect the physiologic angiogenesis process. To overcome limitations of current in vitro angiogenesis assay systems using mainly endothelial cells, we developed a 3-dimensional (3D) co-culture spheroid sprouting assay system. Co-culture spheroids were produced by two human vascular cell precursors, endothelial colony forming cells (ECFCs) and mesenchymal stem cells (MSCs) with a ratio of 5 to 1. ECFCs+MSCs spheroids were embedded into type I collagen matrix to mimic the in vivo extracellular environment. A real-time cell recorder was utilized to continuously observe the progression of angiogenic sprouting from spheroids for 24 h. Live cell fluorescent labeling technique was also applied to tract the localization of each cell type during sprout formation. Angiogenic potential was quantified by counting the number of sprouts and measuring the cumulative length of sprouts generated from the individual spheroids. Five randomly-selected spheroids were analyzed per experimental group. Comparison experiments demonstrated that ECFCs+MSCs spheroids showed greater sprout number and cumulative sprout length compared with ECFCs-only spheroids. Bevacizumab, an FDA-approved angiogenesis inhibitor, was tested with the newly-developed co-culture spheroid assay system to verify its potential to screen anti-angiogenic drugs. The IC50 value for ECFCs+MSCs spheroids compared to the ECFCs-only spheroids was closer to the effective plasma concentration of bevacizumab obtained from the xenograft tumor mouse model. The present study suggests that the 3D ECFCs+MSCs spheroid angiogenesis assay system is relevant to physiologic angiogenesis, and can predict an effective plasma concentration in advance of animal experiments.

Three-dimensional co-culture spheroid angiogenesis assay system is designed to mimic the physiologic angiogenesis. Co-culture spheroids are formed by two human vascular cell precursors, ECFCs and MSCs, and embedded in collagen gel. The new system is effective for evaluating angiogenic modulators, and provides more relevant information to the in vivo study.

Studies in the field of angiogenesis have been aggressively growing in the last few decades with the recognition that angiogenesis is a hallmark of more ...

Analysis of Hematopoietic Stem Progenitor Cell Metabolism

Hematopoietic stem progenitor cells (HSPCs) have distinct metabolic plasticity, which allows them to transition from their quiescent state to a differentiation state to sustain demands of the blood formation. However, it has been difficult to analyze the metabolic status (mitochondrial respiration and glycolysis) of HSPCs due to their limited numbers and lack of optimized protocols for non-adherent, fragile HSPCs. Here, we provide a set of clear, step-by-step instructions to measure metabolic respiration (oxygen consumption rate; OCR) and glycolysis (extracellular acidification rate; ECAR) of murine bone marrow-LineagenegSca1+c-Kit+ (LSK) HSPCs. This protocol provides a higher amount of LSK HSPCs from murine bone marrow, improves the viability of HSPCs during incubation, facilitates extracellular flux analyses of non-adherent HSPCs, and provides optimized injection protocols (concentration and time) for drugs targeting oxidative phosphorylation and glycolytic pathways. This method enables the prediction of the metabolic status and the health of HSPCs during blood development and diseases.

Hematopoietic stem progenitor cells (HSPCs) transition from a quiescent state to a differentiation state due to their metabolic plasticity during blood formation. Here, we present an optimized method for measuring mitochondrial respiration and glycolysis of HSPCs.