We acknowledge the contribution of Renata Sano in conceiving the initial protocol. A.d&#x2019;A. holds the Jewelers For Children (JFC) Endowed Chair in Genetics and Gene Therapy. This work was funded in part by NIH grants GM60905, DK52025 and CA021764, and the American Lebanese Syrian Associated Charities (ALSAC).

The following protocol is intended for the isolation and purification of MAMs and GEMs from mouse brain.
Solutions required for Isolation of mitochondria, MAMs and GEMs.
Fractionation to obtain crude mitochondrial preparation:
Solution A: 0.32 M Sucrose, 1 mM NaHCO3, 1 mM MgCl2, 0.5 mM CaCl2 + Protease Inhibitors (add fresh, as needed).
Solution B: 0.32 M Sucrose, 1 mM NaHCO3 + Protease Inhibitors (add fresh, as needed).
MAMs Isolation:
Isolation Medium: 250 mM Mannitol, 5 mM HEPES pH 7.4, 0.5 mM EGTA, 0.1% BSA.
Gradient Buffer: 225 mM Mannitol, 25 mM HEPES pH 7.5, 1 mM EGTA, 0.1% BSA (final concentration).
GEMs Isolation:
GEM Extraction Buffer: 25 mM HEPES pH 7.5, 0.15 M NaCl, 1% Triton X-100 + Protease Inhibitors (add fresh, as needed).
GEM Solubilising Buffer: 50 mM Tris-HCl, pH 8.8, 5 mM EDTA , 1% SDS + Protease Inhibitors (add fresh, as needed).
1. First Step Subcellular Fractionation: Removal of Nuclei, Unlysed Cells and Cellular Debris
<ol>
 <li>Euthanize mouse in CO2 chamber.
 </li>
 <li>Immediately remove brain, halve, place in 2 ml tubes on ice and weigh. </li>
</ol>
Note: Keep brain halves separate throughout the entire procedure. The following applies to the treatment of a single brain half. 
<ol start="3">
 <li>Place half brain in a pre-chilled 2 ml glass Dounce tissue grinder containing 1 ml cold Solution A. Homogenize with 15 total strokes of a large clearance pestle. </li>
 <li>Transfer to a 15 ml falcon tube, on ice, and dilute homogenates up to 10 volumes w/v, e.g. 0.225 g to 2.25 ml. </li>
 <li>Centrifuge sample at 1,400 x g for 10 min at 4 &deg;C.
 </li>
 <li>Carefully remove the supernatant and transfer to a 30 ml round-bottom glass centrifuge tube, on ice. Make sure not to disturb the pellet. </li>
 <li>Resuspend the pellet in the same 10 volumes of Solution A. Homogenize in the same grinder, with 3-6 strokes of a small clearance pestle, 1 ml at a time. </li>
 <li>Transfer to a fresh 15 ml falcon tube and centrifuge at 710 x g for 10 min at 4 &deg;C. This results in a pellet of nuclei and cell debris. </li>
 <li>Carefully remove the supernatant and pool with the supernatant saved in step 1.6. </li>
</ol>
2. Second Step: Crude Mitochondria Isolation
<ol>
 <li>Centrifuge supernatants at 13,800 x g for 10 min at 4 &deg;C. </li>
 <li>Transfer supernatant to an Ultra-Clear Beckman Centrifuge Tube, on ice </li>
 <li>Resuspend pellet in 10 volumes Solution A. Homogenize in the same grinder, with 3-6 strokes of a small clearance pestle, 1 ml at a time. </li>
 <li>Centrifuge as step 2.1. </li>
 <li>Repeat steps 2.2-2.4. </li>
 <li>The resulting pellet is an enriched mitochondrial fraction. Pool the supernatants (cytosol and ER), cover with parafilm and keep on ice.</li>
 <li>Resuspend the pellet with 6 strokes of a small clearance pestle, in 4.8 ml/g (g is referred to the original brain weight) of Solution B, in a fresh homogeniser. </li>
 <li>Using glass Pasteur pipettes, prepare a Discontinuous Sucrose Gradient in an Ultra-Clear Beckman Centrifuge Tube, adding subsequently to the bottom of the tube as follows, carefully, ensuring no bubbles are formed: 
 Resupended Pellet (0.32 M Sucrose) 
 3 ml 850 mM Sucrose (in 1 mM NaHCO3) 
 3 ml 1 M Sucrose (in 1 mM NaHCO3) 
 3 ml 1.2 M Sucrose (in 1 mM NaHCO3) </li>
 <li>Centrifuge at 82,500 x g for 2 hr at 4 &deg;C. The resulting separation at the end of the gradient will produce three bands and a pellet: 1) myelin and other membrane contaminants (0.32 M - 0.85 M interface); 2) ER, Golgi, plasma membranes (0.85 M - 1 M interface); 3) synaptosomes (1 M - 1.2 M interface); 4) crude mitochondria (pellet) that is used for the subsequent purification steps
 
 </li>
</ol>
3. Isolation of Mitochondria-associated ER Membrane, MAMs
<ol>
 <li>Resuspend the freshly isolated crude mitochondria from one brain half, in 2 ml Isolation Medium containing freshly added protease inhibitors. 
 </li>
 <li>Prepare a 30% Percoll gradient with Gradient Buffer 8 ml per half brain, and place in an Ultra-Clear Beckman Centrifuge Tube. </li>
</ol>
* Note: Make gradient buffer more concentrated (1.43 times) to achieve correct final concentration after diluting Percoll to 30%.
<ol start="3">
 <li>Layer mitochondrial suspension on top of prepared gradient SLOWLY to avoid any bubbles.</li>
 <li>Centrifuge at 95,000 x g for 30 min, 4 &deg;C.
 </li>
 <li><ol class="lroman">
 <li> Remove the Heavy Fraction (lower band) FIRST with a glass Pasteur pipette and transfer to a fresh round-bottom glass tube, on ice.</li>
 <li> Remove the Light Fraction (upper band) SECOND with another glass Pasteur pipette and transfer to a separate fresh round-bottom glass tube, on ice. </li>
 </ol>
 </li>
 <li>Dilute both fractions collected in step 3.5 with 10 ml Isolation Medium and centrifuge at 6,300 x g for 10 min at 4 &deg;C.
 </li>
 <li>Discard the supernatant from the Heavy Fraction obtained in step 3.6, resuspend the pellet with another 10 ml Isolation Medium and centrifuge again, as step 3.6. The resulting pellet will be the pure mitochondrial fraction. </li>
 <li>Transfer the supernatant from the Light Fraction obtained in step 3.6 to an Ultra-Clear Beckman Centrifuge Tube, on ice. Discard the pellet. </li>
 <li>Add sufficient Isolation Medium to the supernatant obtained in step 3.8 to fill the tube and centrifuge at 100,000 x g for 1 hr, 4 &deg;C. The resulting pellet will be the MAMs fraction. Carefully remove and discard the supernatant. </li>
</ol>
Note: At this step, you may also centrifuge at 100,000 x g for 1 hr, 4 &deg;C the supernatant saved at step 2.6. The pellet will be the ER fraction and supernatant the Cytosolic fraction.
4. Extraction of Glycosphingolipid-enriched Microdomains, GEMs 
<ol>
 <li>Lyse pure mitochondria and/or MAM fractions in 500 &mu;l-1 ml of Extraction Buffer for 20 min on ice.</li>
 <li>Centrifuge lysates at 15,300 x g for 2 min at 4 &deg;C. </li>
 <li>Collect supernatants (Triton X-100 soluble material) and re-centrifuge pellets for 2 min to remove remaining soluble material. (Triton X-100 extracted Mitochondria and/or Triton X-100 extracted MAMs).</li>
 <li>Solubilize pellets in Solubilising Buffer. This solubilized material represents the GEM fractions and can be used for further analysis.</li>
</ol>

<ol>
	<li>Poburko, D., Kuo, K. H., Dai, J., Lee, C. H., van Breemen, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organellar+junctions+promote+targeted+Ca2++signaling+in+smooth+muscle:+why+two+membranes+are+better+than+one.">Organellar junctions promote targeted Ca2+ signaling in smooth muscle: why two membranes are better than one.</a> Trends Pharmacol. Sci. 25 (1), 8-15 (2004).</li><li>Pani, B., Ong, H. L., Liu, X., Rauser, K., Ambudkar, I. S., Singh, B. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipid+rafts+determine+clustering+of+STIM1+in+endoplasmic+reticulum-plasma+membrane+junctions+and+regulation+of+store-operated+Ca2++entry+(SOCE.">Lipid rafts determine clustering of STIM1 in endoplasmic reticulum-plasma membrane junctions and regulation of store-operated Ca2+ entry (SOCE.</a> J. Biol. Chem. 283 (25), 17333-17340 (2008).</li><li>Levine, T., Rabouille, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endoplasmic+reticulum:+one+continuous+network+compartmentalized+by+extrinsic+cues.">Endoplasmic reticulum: one continuous network compartmentalized by extrinsic cues.</a> Curr. Opin. Cell Biol. 17 (4), 362-368 (2005).</li><li>Sano, R., Annunziata, I., Patterson, A., Moshiach, S., Gomero, E., Opferman, J., Forte, M., d'Azzo, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=GM1-ganglioside+accumulation+at+the+mitochondria-associated+ER+membranes+links+ER+stress+to+Ca(2+)-dependent+mitochondrial+apoptosis.">GM1-ganglioside accumulation at the mitochondria-associated ER membranes links ER stress to Ca(2+)-dependent mitochondrial apoptosis.</a> Mol. Cell. 36 (3), 500-511 (2009).</li><li>Raturi, A., Simmen, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Where+the+endoplasmic+reticulum+and+the+mitochondrion+tie+the+knot:+The+mitochondria-associated+membrane+(MAM).">Where the endoplasmic reticulum and the mitochondrion tie the knot: The mitochondria-associated membrane (MAM).</a> Biochim. Biophys. Acta. , (2012).</li><li>Giorgi, C., De Stefani, D., Bononi, A., Rizzuto, R., Pinton, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+and+functional+link+between+the+mitochondrial+network+and+the+endoplasmic+reticulum.">Structural and functional link between the mitochondrial network and the endoplasmic reticulum.</a> Int. J. Biochem. Cell Biol. 41 (10), 1817-1827 (2009).</li><li>d'Azzo, A., Tessitore, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sano+Gangliosides+as+apoptotic+signals+in+ER+stress+response.">Sano Gangliosides as apoptotic signals in ER stress response.</a> Cell Death Differ. 13, 404-414 (2006).</li><li>Kroemer, G., Galluzzi, L., Brenner, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitochondrial+membrane+permeabilization+in+cell+death.">Mitochondrial membrane permeabilization in cell death.</a> Physiol. Rev. 87, 99-163 (2007).</li><li>Rizzuto, R., Brini, M., Murgia, M., Pozzan, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microdomains+with+high+Ca2++close+to+IP3-sensitive+channels+that+are+sensed+by+neighboring+mitochondria.">Microdomains with high Ca2+ close to IP3-sensitive channels that are sensed by neighboring mitochondria.</a> Science. 262, 744-747 (1993).</li><li>Lynes, E. M., Bui, M., Yap, M. C., Benson, M. D., Schneider, B., Ellgaard, L., Berthiaume, L. G., Simmen, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Palmitoylated+TMX+and+calnexin+target+to+the+mitochondria-associated+membrane.">Palmitoylated TMX and calnexin target to the mitochondria-associated membrane.</a> EMBO J. 31 (2), 457-470 (2011).</li><li>Fujimoto, M., Hayashi, T., Su, T. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+cholesterol+in+the+association+of+endoplasmic+reticulum+membranes+with+mitochondria.">The role of cholesterol in the association of endoplasmic reticulum membranes with mitochondria.</a> Biochem. Biophys. Res. Commun. 417 (1), 635-639 (2012).</li><li>Grimm, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+ER-mitochondria+interface:+the+social+network+of+cell+death.">The ER-mitochondria interface: the social network of cell death.</a> Biochim. Biophys. Acta. 1823 (2), 327-334 (2012).</li><li>Vance, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phospholipid+synthesis+in+a+membrane+fraction+associated+with+mitochondria.">Phospholipid synthesis in a membrane fraction associated with mitochondria.</a> J. Biol. Chem. 265, 7248-7256 (1990).</li><li>Wieckowski, M. R., Giorgi, C., Lebiedzinska, M., Duszynski, J., Pinton, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+mitochondria-associated+membranes+and+mitochondria+from+animal+tissues+and+cells.">Isolation of mitochondria-associated membranes and mitochondria from animal tissues and cells.</a> Nat. Protoc. 4 (11), 1582-1590 (2009).</li><li>Pizzo, P., Viola, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lymphocyte+lipid+rafts:+structure+and+function.">Lymphocyte lipid rafts: structure and function.</a> Curr. Opin. Immunol. 15 (3), 255-260 (2003).</li></ol>

None of the authors have any conflicts of interest to declare.

The sites of contact between intracellular membranes or between organelles and the plasma membrane of cells represent dynamic signaling platforms for basic cellular processes. The accurate characterization of their function and composition under both physiological and pathological conditions requires reliable and reproducible purification protocols. The methods detailed here have been specifically optimized by our lab for the isolation and purification of the MAMs and their corresponding GEMs from the adult mouse brain. ...

<table border="1">
 <tbody>
 <tr>
 <td>Name of Reagent/Material</td>
 <td>Company</td>
 <td>Catalogue Number</td>
 <td>Comments</td>
 </tr>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>REAGENTS</td>
 </tr>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>Fractionation</td>
 </tr>
 <tr>
 <td>Sucrose</td>
 <td>Fisher Scientific</td>
 <td>S5-500</td>
 <td></td>
 </tr>
 <tr>
 <td>Sodium Bicarbonate</td>
 <td>Sigma-Aldrich</td>
 <td>S-5761</td>
 <td></td>
 </tr>
 <tr>
 <td>Magnesium Chloride, Hexahydrate</td>
 <td>Fisher Scientific</td>
 <td>BP214-500</td>
 <td></td>
 </tr>
 <tr>
 <td>Calcium Chloride, Dihydrate</td>
 <td>Sigma-Aldrich</td>
 <td>C-5080</td>
 <td></td>
 </tr>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>MAM </td>
 </tr>
 <tr>
 <td>D-Mannitol</td>
 <td>Sigma-Aldrich</td>
 <td>M9546-250G</td>
 <td></td>
 </tr>
 <tr>
 <td>Hepes</td>
 <td>Fisher Scientific</td>
 <td>BP310-500</td>
 <td></td>
 </tr>
 <tr>
 <td>EGTA</td>
 <td>Sigma-Aldrich</td>
 <td>E4378-250G</td>
 <td></td>
 </tr>
 <tr>
 <td>BSA, Fraction V, Heat Shock, Lyophilizate</td>
 <td>Roche</td>
 <td>03-116-964-001</td>
 <td></td>
 </tr>
 <tr>
 <td>Percoll</td>
 <td>GE</td>
 <td>17-0891-02</td>
 <td></td>
 </tr>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>GEM </td>
 </tr>
 <tr>
 <td>Triton X-100</td>
 <td>Sigma-Aldrich</td>
 <td>T9284-500 ml</td>
 <td></td>
 </tr>
 <tr>
 <td>Sodium Chloride</td>
 <td>Fisher Scientific</td>
 <td>S271-3</td>
 <td></td>
 </tr>
 <tr>
 <td>Tris Base</td>
 <td>Roche</td>
 <td>03-118-142-001</td>
 <td></td>
 </tr>
 <tr>
 <td>HCl</td>
 <td>Fisher Scientific</td>
 <td>A144S-500</td>
 <td></td>
 </tr>
 <tr>
 <td>EDTA</td>
 <td>Fisher Scientific</td>
 <td>BP120-500</td>
 <td></td>
 </tr>
 <tr>
 <td>Sodium Dodecyl Sulfate (SDS)</td>
 <td>Fisher Scientific</td>
 <td>BP166-500</td>
 <td></td>
 </tr>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>Common </td>
 </tr>
 <tr>
 <td>Protease Inhibitors Tablets, Complete EDTA-free</td>
 <td>Roche</td>
 <td>11-873-580-001</td>
 <td></td>
 </tr>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>EQUIPMENT </td>
 </tr>
 <tr>
 <td>2 ml Douce All-Glass Tissue Grinders</td>
 <td>Kimble Chase</td>
 <td>885300-0002</td>
 <td></td>
 </tr>
 <tr>
 <td>15 ml Polypropylene Conical Centrifuge Tubes, BD Falcon</td>
 <td>BD</td>
 <td>352097</td>
 <td></td>
 </tr>
 <tr>
 <td>30 ml Round-Bottom Glass Centrifuge Tubes</td>
 <td>Kimble Chase</td>
 <td>45500-30</td>
 <td></td>
 </tr>
 <tr>
 <td>15 ml Round-Bottom Glass Centrifuge Tubes</td>
 <td>Kimble Chase</td>
 <td>45500-15</td>
 <td></td>
 </tr>
 <tr>
 <td>Ultracentrifuge tubes, Ultra-Clear, Thinwall, 14x89 mm</td>
 <td>Beckman-Coulter</td>
 <td>344059</td>
 <td></td>
 </tr>
 <tr>
 <td>Parafilm</td>
 <td>Cole-Parmer</td>
 <td>PM996</td>
 <td></td>
 </tr>
 <tr>
 <td>Disposable Borosilicate Glass Pasteur Pipets, 9"</td>
 <td>Fisher Scientific</td>
 <td>13-678-20C</td>
 <td></td>
 </tr>
 </tbody>
</table>

mitochondria-associated er membranes (mams) and glycosphingolipid enriched microdomains (gems): isolation from mouse brain

Intracellular organelles are highly dynamic structures with varying shape and composition, which are subjected to cell-specific intrinsic and extrinsic cues. Their membranes are often juxtaposed at defined contact sites, which become hubs for the exchange of signaling molecules and membrane components1,2,3,4. The inter-organellar membrane microdomains that are formed between the endoplasmic reticulum (ER) and the mitochondria at the opening of the IP3-sensitive Ca2+ channel are known as the mitochondria associated-ER membranes or MAMs4,5,6. The protein/lipid composition and biochemical properties of these membrane contact sites have been extensively studied particularly in relation to their role in regulating intracellular Ca2+ 4,5,6. The ER serves as the primary store of intracellular Ca2+, and in this capacity regulates a myriad of cellular processes downstream of Ca2+ signaling, including post-translational protein folding and protein maturation7. Mitochondria, on the other hand, maintain Ca2+ homeostasis, by buffering cytosolic Ca2+ concentration thereby preventing the initiation of apoptotic pathways downstream of Ca2+ unbalance4,8. The dynamic nature of the MAMs makes them ideal sites to dissect basic cellular mechanisms, including Ca2+ signaling and regulation of mitochondrial Ca2+ concentration, lipid biosynthesis and transport, energy metabolism and cell survival 4,9,10,11,12. Several protocols have been described for the purification of these microdomains from liver tissue and cultured cells13,14. 
	Taking previously published methods into account, we have adapted a protocol for the isolation of mitochondria and MAMs from the adult mouse brain. To this procedure we have added an extra purification step, namely a Triton X100 extraction, which enables the isolation of the glycosphingolipid enriched microdomain (GEM) fraction of the MAMs. These GEM preparations share several protein components with caveolae and lipid rafts, derived from the plasma membrane or other intracellular membranes, and are proposed to function as gathering points for the clustering of receptor proteins and for protein&#x2013;protein interactions4,15.

Based on our experience with using this protocol we can safely recommend it for the isolation and purification of MAMs, GEMs and mitochondrial fractions from mouse brain. The procedure as outlined is highly reproducible and consistent. In Figure 1 we show a representative image of the way pure mitochondria and MAMs layer on a Percoll gradient (step 3.4). A defined, milky band containing purified mitochondria (Mito-P) segregates at the bottom of the ultracentrifuge tube, while the MAM fraction makes up a ...

Watch this Scientific Journal Video about Mitochondria-associated ER Membranes MAMs and Glycosphingolipid Enriched Microdomains GEMs: Isolation from Mouse Brain at JoVE.com

Mitochondria-associated ER Membranes MAMs and Glycosphingolipid Enriched Microdomains GEMs: Isolation from Mouse Brain

This procedure illustrates how to isolate from the adult mouse brain the mitochondria-associated ER membranes or MAMs and the glycosphingolipid-enriched microdomain fractions from MAMs and mitochondrial preparations.

Mitochondria-associated ER Membranes (MAMs) and Glycosphingolipid Enriched Microdomains (GEMs): Isolation from Mouse Brain

Intracellular organelles are highly dynamic structures with varying shape and composition, which are subjected to cell-specific intrinsic and extrinsic ...

mitochondria-associated-er-membranes-mams-glycosphingolipid-enriched

Research

JoVE Journal

Neuroscience

24.3K Views.  St Jude Children's Research Hospital. This procedure illustrates how to isolate from the adult mouse brain the mitochondria-associated ER membranes or MAMs and the glycosphingolipid-enriched microdomain fractions from MAMs and mitochondrial preparations.

Video: Mitochondria-associated ER Membranes MAMs and Glycosphingolipid Enriched Microdomains GEMs: Isolation from Mouse Brain

Derivation of Enriched Oligodendrocyte Cultures and Oligodendrocyte/Neuron Myelinating Co-cultures from Post-natal Murine Tissues

Identifying the molecular mechanisms underlying OL development is not only critical to furthering our knowledge of OL biology, but also has implications for understanding the pathogenesis of demyelinating diseases such as Multiple Sclerosis (MS). Cellular development is commonly studied with primary cell culture models. Primary cell culture facilitates the evaluation of a given cell type by providing a controlled environment, free of the extraneous variables that are present in vivo. While OL cultures derived from rats have provided a vast amount of insight into OL biology, similar efforts at establishing OL cultures from mice has been met with major obstacles. Developing methods to culture murine primary OLs is imperative in order to take advantage of the available transgenic mouse lines. 
Multiple methods for extraction of OPCs from rodent tissue have been described, ranging from neurosphere derivation, differential adhesion purification and immunopurification 1-3. While many methods offer success, most require extensive culture times and/or costly equipment/reagents. To circumvent this, purifying OPCs from murine tissue with an adaptation of the method originally described by McCarthy &amp; 
de Vellis 2 is preferred. This method involves physically separating OPCs from a mixed glial culture derived from neonatal rodent cortices. The result is a purified OPC population that can be differentiated into an OL-enriched culture. This approach is appealing due to its relatively short culture time and the unnecessary requirement for growth factors or immunopanning antibodies. 
While exploring the mechanisms of OL development in a purified culture is informative, it does not provide the most physiologically relevant environment for assessing myelin sheath formation. Co-culturing OLs with neurons would lend insight into the molecular underpinnings regulating OL-mediated myelination of axons. For many OL/neuron co-culture studies, dorsal root ganglion neurons (DRGNs) have proven to be the neuron type of choice. They are ideal for co-culture with OLs due to their ease of extraction, minimal amount of contaminating cells, and formation of dense neurite beds. While studies using rat/mouse myelinating xenocultures have been published 4-6, a method for the derivation of such OL/DRGN myelinating co-cultures from post-natal murine tissue has not been described. Here we present detailed methods on how to effectively produce such cultures, along with examples of expected results. These methods are useful for addressing questions relevant to OL development/myelinating function, and are useful tools in the field of neuroscience.

This article describes methods to derive enriched populations of murine oligodendrocyte precursor cells (OPCs) in primary culture, which differentiate to produce mature oligodendrocytes (OLs). In addition, this report describes techniques to produce murine myelinating co-cultures by seeding mouse OPCs onto a neurite bed of mouse dorsal root ganglion neurons (DRGNs).

Identifying the molecular mechanisms underlying OL development is not only critical to furthering our knowledge of OL biology, but also has implications ...

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 ...

Isolation of CA1 Nuclear Enriched Fractions from Hippocampal Slices to Study Activity-dependent Nuclear Import of Synapto-nuclear Messenger Proteins

Studying activity dependent protein expression, subcellular translocation, or phosphorylation is essential to understand the underlying cellular mechanisms of synaptic plasticity. Long-term potentiation (LTP) and long-term depression (LTD) induced in acute hippocampal slices are widely accepted as cellular models of learning and memory. There are numerous studies that use live cell imaging or immunohistochemistry approaches to visualize activity dependent protein dynamics. However these methods rely on the suitability of antibodies for immunocytochemistry or overexpression of fluorescence-tagged proteins in single neurons. Immunoblotting of proteins is an alternative method providing independent confirmation of the findings.&#160;The first limiting factor in preparation of subcellular fractions from individual tetanized hippocampal slices is the low amount of material. Second, the handling procedure is crucial because even very short and minor manipulations of living slices might induce activation of certain signaling cascades. Here we describe an optimized workflow in order to obtain sufficient quantity of nuclear enriched fraction of sufficient purity from the CA1 region of acute hippocampal slices from rat brain. As a representative example we show that the ERK1/2 phosphorylated form of the synapto-nuclear protein messenger Jacob actively translocates to the nucleus upon induction of LTP and can be detected in a nuclear enriched fraction from CA1 neurons.

We provide a detailed protocol for induction of long-term potentiation in the CA1 region of the hippocampus and the subsequent isolation of nuclear enriched fractions from the tetanized area of the slice. This approach can be used to determine activity dependent nuclear protein import in cellular models of learning and memory.

Studying activity dependent protein expression, subcellular translocation, or phosphorylation is essential to understand the underlying cellular ...

Isolation, Culture and Long-Term Maintenance of Primary Mesencephalic Dopaminergic Neurons From Embryonic Rodent Brains

Degeneration of mesencephalic dopaminergic (mesDA) neurons is the pathological hallmark of Parkinson&#8217;s diseae. Study of the biological processes involved in physiological functions and vulnerability and death of these neurons is imparative to understanding the underlying causes and unraveling the cure for this common neurodegenerative disorder. Primary cultures of mesDA neurons provide a tool for investigation of the molecular, biochemical and electrophysiological properties, in order to understand the development, long-term survival and degeneration of these neurons during the course of disease. Here we present a detailed method for the isolation, culturing and maintenance of midbrain dopaminergic neurons from E12.5 mouse (or E14.5 rat) embryos. Optimized cell culture conditions in this protocol result in presence of axonal and dendritic projections, synaptic connections and other neuronal morphological properties, which make the cultures suitable for study of the physiological, cell biological and molecular characteristics of this neuronal population.

The causes of degeneration of midbrain dopaminergic neurons during Parkinson&#8217;s disease are not fully understood. Cellular culture systems provide an essential tool for study of the neurophysiological properties of these neurons. Here we present an optimized protocol, which can be utilized for in vitro modeling of neurodegeneration.

Degeneration of mesencephalic dopaminergic (mesDA) neurons is the pathological hallmark of Parkinson&#8217;s diseae. Study of the biological processes ...

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

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

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

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

Isolation of Cerebral Capillaries from Fresh Human Brain Tissue

Understanding blood-brain barrier function under physiological and pathophysiological conditions is critical for the development of new therapeutic strategies that hold the promise to enhance brain drug delivery, improve brain protection, and treat brain disorders. However, studying the human blood-brain barrier function is challenging. Thus, there is a critical need for appropriate models. In this regard, brain capillaries isolated from human brain tissue represent a unique tool to study barrier function as close to the human in vivo situation as possible. Here, we describe an optimized protocol to isolate capillaries from human brain tissue at a high yield and with consistent quality and purity. Capillaries are isolated from fresh human brain tissue using mechanical homogenization, density-gradient centrifugation, and filtration. After the isolation, the human brain capillaries can be used for various applications including leakage assays, live cell imaging, and immune-based assays to study protein expression and function, enzyme activity, or intracellular signaling. Isolated human brain capillaries are a unique model to elucidate the regulation of the human blood-brain barrier function. This model can provide insights into central nervous system (CNS) pathogenesis, which will help the development of therapeutic strategies for treating CNS disorders.

Isolated brain capillaries from human brain tissue can be used as a preclinical model to study barrier function under physiological and pathophysiological conditions. Here, we present an optimized protocol to isolate brain capillaries from fresh human brain tissue.

Understanding blood-brain barrier function under physiological and pathophysiological conditions is critical for the development of new therapeutic ...

Isolation and RNA Extraction of Neurons, Macrophages and Microglia from Larval Zebrafish Brains

To gain a detailed understanding of the role of different CNS cells during development or the establishment and progression of brain pathologies, it is important to isolate these cells without changing their gene expression profile. The zebrafish model provides a large number of transgenic fish lines in which specific cell types are labelled; for example neurons in the NBT:DsRed line or macrophages/microglia in the mpeg1:eGFP line. Furthermore, antibodies have been developed to stain specific cells, such as microglia with the 4C4 antibody.
Here, we describe the isolation of neurons, macrophages and microglia from larval zebrafish brains. Central to this protocol is the avoidance of an enzymatic tissue digestion at 37 &#176;C, which could modify cellular profiles. Instead a mechanical system of tissue homogenization at 4 &#176;C is used. This protocol entails homogenization of brains into cell suspension, their immuno-staining and the isolation of neurons, macrophages and microglia by FACS. Afterwards, we extracted RNA from those cells and evaluated their quality/quantity. We managed to obtain RNA of high quality (RNA Integrity Number (RIN) &#62; 7) to perform qPCR on macrophages/microglia and neurons, and transcriptomic analysis on microglia. This approach enables a better characterization of these cells, as well as a clearer understanding about their role in development and pathologies.

We present a protocol to isolate neurons, macrophages and microglia from larval zebrafish brains under physiological and pathological conditions. Upon isolation, RNA is extracted from these cells to analyze their gene expression profile. This protocol allows for the collection of high-quality RNA for performing downstream analysis like qPCR and transcriptomics.

To gain a detailed understanding of the role of different CNS cells during development or the establishment and progression of brain pathologies, it is ...

Isolation of Region-specific Microglia from One Adult Mouse Brain Hemisphere for Deep Single-cell RNA Sequencing

As resident macrophages in the central nervous system, microglia actively control brain development and homeostasis, and their dysfunctions may drive human diseases. Considerable advances have been made to uncover the molecular signatures of homeostatic microglia as well as alterations of their gene expression in response to environmental stimuli. With the advent and maturation of single-cell genomic methodologies, it is increasingly recognized that heterogenous microglia may underlie the diverse roles they play in different developmental and pathological conditions. Further dissection of such heterogeneity can be achieved through efficient isolation of microglia from a given region of interest, followed by sensitive profiling of individual cells. Here, we provide a detailed protocol for the rapid isolation of microglia from different brain regions in a single adult mouse brain hemisphere. We also demonstrate how to use these sorted microglia for plate-based deep single-cell RNA sequencing. We discuss the adaptability of this method to other scenarios and provide guidelines for improving the system to accommodate large-scale studies.

We provide a protocol for isolation of microglia from different dissected regions of an adult mouse brain hemisphere, followed by semi-automated library preparation for deep single-cell RNA sequencing of full-length transcriptomes. This method will help to elucidate functional heterogeneity of microglia in health and disease.

As resident macrophages in the central nervous system, microglia actively control brain development and homeostasis, and their dysfunctions may drive ...

Isolation and Expansion of Neurospheres from Postnatal (P1&#8722;3) Mouse Neurogenic Niches

The neurosphere assay is an extremely useful in vitro technique for studying the inherent properties of neural stem/progenitor cells (NSPCs) including proliferation, self-renewal and multipotency. In the postnatal and adult brain, NSPCs are mainly present in two neurogenic niches: the subventricular zone (SVZ) lining the lateral ventricles and the subgranular zone of the hippocampal dentate gyrus (DG). The isolation of the neurogenic niches from postnatal brain allows obtaining a higher amount of NSPCs in culture with a consequent advantage of higher yields. The close contact between cells within each neurosphere creates a microenvironment that may resemble neurogenic niches. Here, we describe, in detail, how to generate SVZ- and DG-derived neurosphere cultures from 1&#8722;3-day-old (P1&#8722;3) mice, as well as passaging, for neurosphere expansion. This is an advantageous approach since the neurosphere assay allows a fast generation of NSPC clones (6&#8722;12 days) and contributes to a significant reduction in the number of animal usage. By plating neurospheres in differentiative conditions, we can obtain a pseudomonolayer of cells composed of NSPCs and differentiated cells of different neural lineages (neurons, astrocytes and oligodendrocytes) allowing the study of the actions of intrinsic or extrinsic factors on NSPC proliferation, differentiation, cell survival and neuritogenesis.

In this article, we describe, in detail, a protocol for the generation of neurosphere cultures from postnatal mouse neural stem cells derived from the main mouse neurogenic niches. Neurospheres are used to identify neural stem cells from brain tissue allowing the estimation of precursor cell numbers. Moreover, these 3D structures can be plated in differentiative conditions, giving rise to neurons, oligodendrocytes and astrocytes, allowing the study of cell fate.

The neurosphere assay is an extremely useful in vitro technique for studying the inherent properties of neural stem/progenitor cells (NSPCs) including ...

Studying Pre-formed Fibril Induced &#945;-Synuclein Accumulation in Primary Embryonic Mouse Midbrain Dopamine Neurons

The goal of this protocol is to establish a robust and reproducible model of &#945;-synuclein accumulation in primary dopamine neurons. Combined with immunostaining and unbiased automated image analysis, this model allows for the analysis of the effects of drugs and genetic manipulations on &#945;-synuclein aggregation in neuronal cultures. Primary midbrain cultures provide a reliable source of bona fide embryonic dopamine neurons. In this protocol, the hallmark histopathology of Parkinson&#8217;s disease, Lewy bodies (LB), is mimicked by the addition of &#945;-synuclein pre-formed fibrils (PFFs) directly to neuronal culture media. Accumulation of endogenous phosphorylated &#945;-synuclein in the soma of dopamine neurons is detected by immunostaining already at 7 days after the PFF addition. In vitro cell culture conditions are also suitable for the application and evaluation of treatments preventing &#945;-synuclein accumulation, such as small molecule drugs and neurotrophic factors, as well as lentivirus vectors for genetic manipulation (e.g., with CRISPR/Cas9). Culturing the neurons in 96 well plates increases the robustness and power of the experimental setups. At the end of the experiment, the cells are fixed with paraformaldehyde for immunocytochemistry and fluorescence microscopy imaging. Multispectral fluorescence images are obtained via automated microscopy of 96 well plates. These data are quantified (e.g., counting the number of phospho-&#945;-synuclein-containing dopamine neurons per well) with the use of free software that provides a platform for unbiased high-content phenotype analysis. PFF-induced modeling of phosphorylated &#945;-synuclein accumulation in primary dopamine neurons provides a reliable tool to study the underlying mechanisms mediating formation and elimination of &#945;-synuclein inclusions, with the opportunity for high-throughput drug screening and cellular phenotype analysis.

Here, we present a detailed protocol to study neuronal &#945;-synuclein accumulation in primary mouse dopamine neurons. Phosphorylated &#945;-synuclein aggregates in neurons are induced with pre-formed &#945;-synuclein fibrils. Automated imaging of immunofluorescently labeled cells and unbiased image analysis make this robust protocol suitable for medium-to-high throughput screening of drugs that inhibit &#945;-synuclein accumulation.

The goal of this protocol is to establish a robust and reproducible model of &#945;-synuclein accumulation in primary dopamine neurons. Combined with ...