This study was supported by grants from the Vanderbilt-Ingram Cancer Center Support Grant (P30 CA068485), the Childhood Brain Tumor Foundation and the National Institutes of Health (NS042205).

1. Micro-dissection of Tumor-bearing Cerebellum, Dissociation of Tumor Tissue and Plating
<ol>
 <li>Retrieval of tumor tissue
 <ol>
 <li>Sick mice bearing medulloblastoma were often runted, displayed hydrocephaly and typical neurological symptoms, including posterior paralysis and failure to regain posture when overturned. To retrieve tumor tissue, euthanize mice by carbon dioxide inhalation. It is important not to perform cervical dislocation, a procedure that generates pressure to the posterior skull and can compromise tumor tissue integrity.</li>
 <li>Decapitation is performed immediately after death using a pair of scissors, removing hair and muscle tissue as much as possible for good visualization of the skull. Clean the surface of the skull with Kimwipe soaked with 95% ethanol.</li>
 <li>Use fine scissors to cut an opening along the midline of the skull, and remove skull tissue using fine tweezers, at which point the whole brain including tumor-bearing cerebellum is exposed.</li>
 <li>While the cerebella of healthy adults display well-defined hemispheres and vermis, the cerebella of tumor-bearing mice are often enlarged, amorphous with a smooth surface and conspicuous blood vessels. Using sterile techniques, retrieve the cerebellar tumor using tweezers and place in ice-cold PBS without Mg2+ and Ca2+.</li>
 </ol>
 
 Note: all instruments are sterilized in 95% ethanol before use.</li>
 <li>Dissociation of tumor tissue
 <ol>
 <li>Transfer the tumor tissue from PBS to 50% Accutase (diluted in PBS) that is about 4 times the volume of the tumor tissue, mince the tissue with fine scissors for 3 minutes at room temperature, followed by incubation at 37&deg;C for 4 minutes, after which the tissue undergoes repetitive pipeting with a 1-mL Pipetman for additional 3 minutes. This method should yield a mixture of single cells and small cellular aggregates.</li>
 <li>Dilute the cellular suspension 3-fold with PBS and centrifuge for 5 minutes at 1000 g to pellet the cells. Resuspend the cell pellet in fresh neural stem cell culture medium and plate onto a gelatinized 60 mm Primaria tissue culture dish. We use Primaria dishes for enhanced attachment at first plating; subsequent passages may be plated onto regular tissue culture dishes.</li>
 </ol>
 </li>
</ol>
Note: Coat culture dishes with 0.1% gelatin for at least 30 minutes. Prepare fresh neural stem cell culture medium consisting of Neurobasal medium with glutamine, Pen-Strep, N2, B27, human EGF (25 ng/ mL) and basic FGF (25ng/ mL).
2. Enrichment, Maintenance and Expansion of Medulloblastoma Tumor Cells by Serial Passages
We usually get many colonies after 1 week of initial plating (Figure 1). These colonies can be dissociated and replated onto new gelatinized dishes for enrichment of the tumor cell population. First change to new culture medium, then simply use a 1-mL Pipetman to mechanically detach colonies followed by repetitive pipeting for 4 minutes to yield a cellular suspension (no Accutase needed). Check under a microscope to ensure that large cell clumps have been dissociated. Then dispense cell suspension onto new gelatinized dishes for further culturing and go through the same procedure for additional passages. Unattached tumor cells, blood cells and other cell types are removed by serial re-platings, leaving the attached tumor cells to expand rapidly. Change culture medium on the second day following initial seeding, and every other day thereafter.
3. Immunofluorescent Staining and Examination of Cultured Cells
1. Grow tumor cells on glass coverslips
On day 1, place one glass coverslip in each of a 6-well plate, then add 0.1% gelatin for 30 minutes at 37&deg;C. Seed approximately 2-4X 105 tumor cells per mL. The cells should attach overnight and the neural stem cell medium changed on day 3. Staining is performed on day 4.
2 Immunofluorescent staining
Remove culture medium and wash cells twice with ice-cold PBS. Fix the cells with freshly-made 4%PFA for 15 minutes. Briefly wash cells twice with PBS and permeablize with 0.3% Triton (in PBS) for 5 minutes. Briefly wash cells twice with PBS and block with 10% goat serum for 40 minutes. Incubate the cells with primary antibody for 90 minutes, then wash cells three times with PBS, for 5 minutes each. Incubate the cells with secondary antibody for 60 minutes, then wash three times with PBS, 5 minutes each. Mount coverslips onto slides with 5 mL of an aqueous mounting medium and perform confocal microscopy.
4. Differentiation of Tumor Cells
Remove neural stem cell medium and briefly wash cells with PBS twice. Add differentiation medium on day 1, change medium on day 4 and determine level of differentiation by immunofluorescence staining on day 7. The differentiation medium consists of DMEM, Pen-Strep and 10% fetal bovine serum.
5. Representative Results
Morphology results
After Accutase treatment and gentle repetitive pipeting, the tumor tissue should be mostly dissociated into small cellular aggregates and single cells. Many sizable colonies can be observed as early as 5 days after initial plating, as shown by Figure 1. Highly proliferative tumor cells are often bi-polar with high nuclear/cytoplasmic ratio. These cells are seen typically radiating from small cellular aggregates attached to the gelatinized surface. Blood cells, small and round, are usually removed by subsequent media changes and serial platings. After several passages, one can observe uniformly distributed, proliferative Ki67+ tumor cells and little contamination with other cell types (Figure 2).
Expression of neural stem cell markers, clonal analysis and differentiation into multiple lineages
To determine whether the proliferative cells derived from dissociated cerebellar tumor tissue show characteristics of tumor stem cells, we performed further characterization by stem cell marker expression, clonal analysis and differentiation potency. We found that these isolated tumor cells highly express neural stem cell markers such as Sox2 and Nestin (Figure 3). As we retrieved tissues from SmoM2-YFP tumor, all tumor cells express YFP. Consistent with a recent study reporting that primary cilia are important for the development of Shh pathway-dependent medulloblastoma 12, SmoM2-YFP expression was clearly localized to the cilia of Sox2+ tumor cells (Figure 3). When plated at clonal density of 300 cells per mL of culture medium, we observed clonal expansion from a single tumor cell to a sizable colony (Figure 4). Furthermore, these cells were able to differentiate into various neuronal and glial cell types when cultured under pro-differentiation conditions (Figure 5).
<img src="/files/ftp_upload/2086/2086fig1.jpg" alt="Figure 1" /> 
 Figure 1. Morphology of a highly proliferative colony after first plating of dissociated medulloblastoma tissue. Generally, a sizable colony forms within 5 days after initial seeding of dissociated tumor tissue, and a representative one is illustrated here in bright field. Bi-polar, elongated cells radiate from a dense core cell aggregate. Attached to the tumor cells are small, round red blood cells, which are gradually depleted by serial platings.
<img src="/files/ftp_upload/2086/2086fig2.jpg" alt="Figure 2" /> 
 Figure 2. Morphology of established medulloblastoma cells beyond three passages. This bright field image shows the typical appearance of established medulloblastoma cells after several passages. The cells remain mostly bi-polar with high nuclear/cytoplasmic ratio. We show acetylated tubulin staining of tumor cells, most of which are cycling as shown by strong Ki67 expression.
<img src="/files/ftp_upload/2086/2086fig3.jpg" alt="Figure 3" /> 
 Figure 3. Established medulloblastoma cells express neural stem cell markers. SmoM2-YFP marks cells expressing constitutively active Smo, hence Shh pathway activity. All cells of the established medulloblastoma cell lines expressed YFP, and most of them co-expressed high levels of various neural stem cell markers, such as Nestin and Sox2. Interestingly, when we performed YFP signal detection with minimal laser power during confocal microscopy, we detected concentrated YFP signal in the cilia of Sox2+ cells. This observation is consistent with a recent report 12 that described the essential role of cilia in the development of Shh pathway-dependent medulloblastoma.
<img src="/files/ftp_upload/2086/2086fig4.jpg" alt="Figure 4" /> 
 Figure 4. Established tumor cells undergo clonal expansion. After dissociation into single cell suspension, tumor cells were plated onto a 24 well-plate at a clonal density of 300 cells per mL of culture medium. In each well we observed clonally expanded colonies. This series of bright field images demonstrate typical changes over a 10-day period of culture.
<img src="/files/ftp_upload/2086/2086fig5.jpg" alt="Figure 5" /> 
 Figure 5. Differentiation analyses of established medulloblastoma cells. When tumor cells were switched from EGF/bFGF containing serum-free medium to DMEM/10% FBS, YFP+ tumor cells significantly altered their morphology and differentiated into various cell types, including Tuj1+ or NeuN+ neurons, GFAP+ astroglial cells or CNPase+ oligodendrocytes.

<ol>
	<li>Rossi, A., Caracciolo, V., Russo, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Medulloblastoma:+From+Molecular+Pathology+to+Therapy.">Medulloblastoma: From Molecular Pathology to Therapy.</a> Clin Cancer Res. 14 (4), 971-971 (2008).</li><li>Wechsler-Reya, R. J., Scott, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+Neuronal+Precursor+Proliferation+in+the+Cerebellum+by+Sonic+Hedgehog.">Control of Neuronal Precursor Proliferation in the Cerebellum by Sonic Hedgehog.</a> P. Neuron. 22 (1), 103-103 (1999).</li><li>Dahmane, N., Ruiz, A., Altaba, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sonic+hedgehog+regulates+the+growth+and+patterning+of+the+cerebellum.">Sonic hedgehog regulates the growth and patterning of the cerebellum.</a> Development. 126 (14), 3089-3089 (1999).</li><li>Wallace, V. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purkinje-cell-derived+Sonic+hedgehog+regulates+granule+neuron+precursor+cell+proliferation+in+the+developing+mouse+cerebellum.">Purkinje-cell-derived Sonic hedgehog regulates granule neuron precursor cell proliferation in the developing mouse cerebellum.</a> Curr Biol. 9 (8), 445-445 (1999).</li><li>Fan, X., Eberhart, C. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Medullablastoma+Stem+Cells.">Medullablastoma Stem Cells.</a> J Clin Oncol. 26 (17), 2821-2821 (2008).</li><li>Yoon, J. W., Gilbertson, R., Iannaccone, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Defining+a+Role+for+Hedgehog+Pathway+Activation+in+Desmoplastic+Medulloblastoma+by+Identifying+GLI1+Target+Genes.+International+journal+of+cancer.">Defining a Role for Hedgehog Pathway Activation in Desmoplastic Medulloblastoma by Identifying GLI1 Target Genes. International journal of cancer.</a> 124 (1), 109-109 (2009).</li><li>O'Dorisio, M. S., Khanna, G., Bushnell, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combining+anatomic+and+molecularly+targeted+imaging+in+the+diagnosis+and+surveillance+of+embryonal+tumors+of+the+nervous+and+endocrine+systems+in+children.+Review.">Combining anatomic and molecularly targeted imaging in the diagnosis and surveillance of embryonal tumors of the nervous and endocrine systems in children. Review.</a> Cancer metastasis reviews. 27 (4), 665-665 (2008).</li><li>Corcoran, R. B., Bachar Raveh, T., Barakat, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insulin-like+Growth+Factor+2+Is+Required+for+Progression+to+Advanced+Medulloblastoma+in+patched1+Heterozygous+Mice.">Insulin-like Growth Factor 2 Is Required for Progression to Advanced Medulloblastoma in patched1 Heterozygous Mice.</a> Cancer research. 68 (21), 8788-8788 (2008).</li><li>Gilbertson, R. J., Ellison, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Origins+of+Medulloblastoma+Subtypes.">The Origins of Medulloblastoma Subtypes.</a> Annual review of pathology. 3, 341-341 (2008).</li><li>Ward, R. J., Lee, L., Graham, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multipotent+CD15++Cancer+Stem+Cells+in+Patched-1+Deficient+Mouse+Medulloblastoma.">Multipotent CD15+ Cancer Stem Cells in Patched-1 Deficient Mouse Medulloblastoma.</a> Cancer research. 69 (11), 4682-4682 (2009).</li><li>Mao, J., Ligon, K. L., Rakhlin, E. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Novel+Somatic+Mouse+Model+to+Survey+Tumorigenic+Potential+Applied+to+the+Hedgehog+Pathway.">A Novel Somatic Mouse Model to Survey Tumorigenic Potential Applied to the Hedgehog Pathway.</a> Cancer research. 66, 10171-10171 (2006).</li><li>Han, Y. G., Kim, H. J., Dlugosz, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dual+and+opposing+roles+of+primary+cilia+in+medulloblastoma+development.">Dual and opposing roles of primary cilia in medulloblastoma development.</a> Nature medicine. 15 (9), 1062-1062 (2009).</li></ol>

No conflicts of interest declared.

We describe an efficient way to isolate, enrich and maintain medulloblastoma stem cells from primary tumor tissue retrieved from mutant mice with constitutively active Hedgehog signaling. We found that one critical step in successfully establishing a healthy tumor stem cell line is the Accutase treatment used during dissociation of the primary tumor tissue. In our experience, when first dissociating tumor tissue from the cerebellum, 4 minutes of 50% Accutase treatment at 37&deg;C, followed by 3 minutes of repetitive pipe...

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		<div>
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		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Neurobasal medium</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>21103049</td>
<td>&nbsp;</td>
<tr>
<td>hEGF</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>PHG0311</td>
<td>25ng/ml</td>
</tr>
<tr>
<td>bFGF</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>PHG0023</td>
<td>25ng/ml</td>
</tr>
<tr>
<td>N2</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>17502048</td>
<td>1X</td>
</tr>
<tr>
<td>B27(-RA)</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>12587010</td>
<td>1X</td>
</tr>
<tr>
<td>Accutase</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>A1110501</td>
<td>50%</td>
</tr>
<tr>
<td>Gelatin</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>G1393</td>
<td> 0.1%</td>
</tr>
<tr>
<td>Glutamine</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>25030081</td>
<td>2mM</td>
</tr>
<tr>
<td>Primaria dishes</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>087724C</td>
<td>&nbsp;</td>
<tr>
<td>Sox2 antibody</td>
<td>&nbsp;</td>
<td>Millipore</td>
<td>MAB4343</td>
<td>Mouse, 1:1000</td>
</tr>
<tr>
<td>Nestin antibody</td>
<td>&nbsp;</td>
<td>DSHB</td>
<td>rat401</td>
<td>Mouse, 1:200</td>
</tr>
<tr>
<td>YFP antibody</td>
<td>&nbsp;</td>
<td>Molecular Probes</td>
<td>A11122</td>
<td>Rabbit, 1:2000</td>
</tr>
<tr>
<td>GFAP antibody</td>
<td>&nbsp;</td>
<td>Neuromics</td>
<td>CH22102</td>
<td>Chicken, 1:1000</td>
</tr>
<tr>
<td>Tuj1 antibody</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>T5076</td>
<td>Mouse, 1:2000</td>
</tr>
<tr>
<td>NeuN antibody</td>
<td>&nbsp;</td>
<td>Millipore</td>
<td>MAB377</td>
<td>Mouse, 1:2000</td>
</tr>
<tr>
<td>CNPase antibody</td>
<td>&nbsp;</td>
<td>Millipore</td>
<td>MAB326</td>
<td>Mouse, 1:1000</td>
</tr>		</tbody>
		</table>
		</div>

isolation, enrichment, and maintenance of medulloblastoma stem cells

Brain tumors have been suggested to possess a small population of stem cells that are the root cause of tumorigenesis. Neurosphere assays have been generally adopted to study the nature of neural stem cells, including those derived from normal and tumorous tissues. However, appreciable amounts of differentiation and cell death are common in cultured neurospheres likely due to sub-optimal condition such as accessibility of all cells within sphere aggregates to culture medium.
Medulloblastoma, the most common pediatric CNS tumor, is characterized by its rapid progression and tendency to spread along the entire brain-spinal axis with dismal clinical outcome. Medulloblastoma is a neuroepithelial tumor of the cerebellum, accounting for 20% and 40% of intracranial and posterior fossa tumor in childhood, respectively1. It is now well established that Shh signaling stimulates proliferation of cerebellar granule neuron precursors (CGNPs) during cerebellar development 2-4. Numerous studies using mouse models, in which the Shh pathway is constitutively activated, have linked Shh signaling with medulloblastoma 5-9.
A recent report has shown that a subset of medulloblastoma cells derived from Patched1LacZ/+ mice are cancer stem cells, which are capable of initiating and propogating tumors 10. Here we describe an efficient method to isolate, enrich and maintain tumor stem cells derived from several mouse models of medulloblastoma, with constitutively activated Shh pathway due to a mutation in Smoothened (11, hereon referred as SmoM2), a GPCR that is critical for Shh pathway activation. In every isolated medulloblastoma tissue, we were able to establish numerous highly proliferative colonies. These cells robustly expressed several neural stem cell markers such as Nestin and Sox2, can undergo serial passages (greater than 20) and were clonogenic. While these cultured tumor stem cells were relatively small, often bipoar with high nuclear to cytoplasmic ratio when cultured under conditions favoring stem cell growth, they dramatically altered their morphology, extended multiple cellular processes, flattened and withdrew from the cell cycle upon switching to a cell culture medium supplemented with 10% fetal bovine serum. More importantly, these tumor stem cells differentiated into Tuj1+ or NeuN+ neurons, GFAP+ astrocytes and CNPase+ oligodendrocytes, thus highlighting their multi-potency. Furthermore, these cells were capable of propagating secondary medulloblastomas when orthotopically transplanted into host mice.

Watch this Scientific Journal Video about Isolation, Enrichment, and Maintenance of Medulloblastoma Stem Cells at JoVE.com

Isolation, Enrichment, and Maintenance of Medulloblastoma Stem Cells

This protocol describes the isolation, enrichment, and maintenance of medulloblastoma tumor stem cells derived from mutant mice with ectopic Sonic hedgehog pathway activity.

Brain tumors have been suggested to possess a small population of stem cells that are the root cause of tumorigenesis. Neurosphere assays have been ...

isolation-enrichment-and-maintenance-of-medulloblastoma-stem-cells

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16.2K Views.  Vanderbilt University. This protocol describes the isolation, enrichment, and maintenance of medulloblastoma tumor stem cells derived from mutant mice with ectopic Sonic hedgehog pathway activity.

Video: Isolation, Enrichment, and Maintenance of Medulloblastoma Stem Cells

Intracranial Orthotopic Allografting of Medulloblastoma Cells in Immunocompromised Mice

Medulloblastoma is the most common pediatric tumor of the nervous system. A large body of animal studies has focused on cerebellar granule neuron precursors (CGNPs) as the cell-of-origin for medulloblastoma1-4. However, the diverse clinical presentations of medulloblastoma subtypes in human patients (nodular, desmoplastic, classical and large cell/anaplastic), and the fact that medulloblastoma is found in a subset of human patients with no ectopic expression of CGNP marker5, suggest that the cellular and molecular origins of medulloblastoma are more complex and far from being completely deciphered. Therefore, it is essential to determine whether there is an alternative medulloblastoma tumor cell-of-origin based on which cell-type specific therapeutic modality can be developed. To this end, intracranial orthotopic allografting of genetically marked tumor cell types followed by subsequent analyses of secondary tumor development in recipients will allow determination of the cellular origin of tumor-initiating cells. Here we describe the experimental protocol for intracranial orthotopic allografting of medulloblastoma cells derived from primary tumor tissue, and this procedure can also be used for transplanting cells from established cell lines.

This protocol describes the isolation and dissociation of mouse medulloblastoma tissue, and subsequent allografting of the tumor cells into immunocompromised recipient mice in order to initiate secondary medulloblastoma.

Medulloblastoma is the most common pediatric tumor of the nervous system. A large body of animal studies has focused on cerebellar granule neuron ...

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 ...

Live-cell Imaging of Sensory Organ Precursor Cells in Intact Drosophila Pupae

Since the discovery of Green Fluorescent Protein (GFP), there has been a revolutionary change in the use of live-cell imaging as a tool for understanding fundamental biological mechanisms. Striking progress has been particularly evident in Drosophila, whose extensive toolkit of mutants and transgenic lines provides a convenient model to study evolutionarily-conserved developmental and cell biological mechanisms. We are interested in understanding the mechanisms that control cell fate specification in the adult peripheral nervous system (PNS) in Drosophila. Bristles that cover the head, thorax, abdomen, legs and wings of the adult fly are individual mechanosensory organs, and have been studied as a model system for understanding mechanisms of Notch-dependent cell fate decisions. Sensory organ precursor (SOP) cells of the microchaetes (or small bristles), are distributed throughout the epithelium of the pupal thorax, and are specified during the first 12 hours after the onset of pupariation. After specification, the SOP cells begin to divide, segregating the cell fate determinant Numb to one daughter cell during mitosis. Numb functions as a cell-autonomous inhibitor of the Notch signaling pathway.
Here, we show a method to follow protein dynamics in SOP cell and its progeny within the intact pupal thorax using a combination of tissue-specific Gal4 drivers and GFP-tagged fusion proteins 1,2.This technique has the advantage over fixed tissue or cultured explants because it allows us to follow the entire development of an organ from specification of the neural precursor to growth and terminal differentiation of the organ. We can therefore directly correlate changes in cell behavior to changes in terminal differentiation. Moreover, we can combine the live imaging technique with mosaic analysis with a repressible cell marker (MARCM) system to assess the dynamics of tagged proteins in mitotic SOPs under mutant or wildtype conditions. Using this technique, we and others have revealed novel insights into regulation of asymmetric cell division and the control of Notch signaling activation in SOP cells (examples include references 1-6,7 ,8).

Live-cell Imaging of Sensory Organ Precursor Cells in Intact Drosophila Pupae

In this video, we describe a method for live cell imaging of asymmetrically dividing sensory organ progenitor cells and epidermal cells in intact Drosophila pupae

Since the discovery of Green Fluorescent Protein (GFP), there has been a revolutionary change in the use of live-cell imaging as a tool for understanding ...

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 ...

The Neuroblast Assay: An Assay for the Generation and Enrichment of Neuronal Progenitor Cells from Differentiating Neural Stem Cell Progeny Using Flow Cytometry

Neural stem cells (NSCs) can be isolated and expanded in large-scale, using the neurosphere assay and differentiated into the three major cell types of the central nervous system (CNS); namely, astrocytes, oligodendrocytes and neurons. These characteristics make neural stem and progenitor cells an invaluable renewable source of cells for in vitro studies such as drug screening, neurotoxicology and electrophysiology and also for cell replacement therapy in many neurological diseases. In practice, however, heterogeneity of NSC progeny, low production of neurons and oligodendrocytes, and predominance of astrocytes following differentiation limit their clinical applications. Here, we describe a novel methodology for the generation and subsequent purification of immature neurons from murine NSC progeny using fluorescence activated cell sorting (FACS) technology. Using this methodology, a highly enriched neuronal progenitor cell population can be achieved without any noticeable astrocyte and bona fide NSC contamination. The procedure includes differentiation of NSC progeny isolated and expanded from E14 mouse ganglionic eminences using the neurosphere assay, followed by isolation and enrichment of immature neuronal cells based on their physical (size and internal complexity) and fluorescent properties using flow cytometry technology. Overall, it takes 5-7 days to generate neurospheres and 6-8 days to differentiate NSC progeny and isolate highly purified immature neuronal cells.

This video protocol demonstrates a novel method for the generation and subsequent purification of neuronal progenitor cells from a renewable source of neural stem cells (NSCs) based on their physical (size and internal granularity) and fluorescent properties using flow cytometry technology.

Neural stem cells (NSCs) can be isolated and expanded in large-scale, using the neurosphere assay and differentiated into the three major cell types of ...

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, 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 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.

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 ...

A Scalable Model to Study the Effects of Blunt-Force Injury in Adult Zebrafish

Blunt-force traumatic brain injuries (TBI) are the most common form of head trauma, which spans a range of severities and results in complex and heterogenous secondary effects. While there is no mechanism to replace or regenerate the lost neurons following a TBI in humans, zebrafish possess the ability to regenerate neurons throughout their body, including the brain. To examine the breadth of pathologies exhibited in zebrafish following a blunt-force TBI and to study the mechanisms underlying the subsequent neuronal regenerative response, we modified the commonly used rodent Marmarou weight drop for the use in adult zebrafish. Our simple blunt-force TBI model is scalable, inducing a mild, moderate, or severe TBI, and recapitulates many of the phenotypes observed following human TBI, such as contact- and post-traumatic seizures, edema, subdural and intracerebral hematomas, and cognitive impairments, each displayed in an injury severity-dependent manner. TBI sequelae, which begin to appear within minutes of the injury, subside and return to near undamaged control levels within 7 days post-injury. The regenerative process begins as early as 48 hours post-injury (hpi), with the peak cell proliferation observed by 60 hpi. Thus, our zebrafish blunt-force TBI model produces characteristic primary and secondary injury TBI pathologies similar to human TBI, which allows for investigating disease onset and progression, along with the mechanisms of neuronal regeneration that is unique to zebrafish.

We modified the Marmarou weight drop model for adult zebrafish to examine a breadth of pathologies following blunt-force traumatic brain injury (TBI) and the mechanisms underlying subsequent neuronal regeneration. This blunt-force TBI model is scalable, induces a mild, moderate, or severe TBI, and recapitulates injury heterogeneity observed in human TBI.