We thank Evan Dysart and Marc L&eacute;onard for expert technical assistance in video production and editing, Matt Cooke for assistance in data collection, and Sarah Gelbard for expert editorial assistance. The work was funded by operating grants from the Canadian Institute of Health Research (CIHR, MOP 62626) to SALB, a Strategic Training Initiative in Health Research program grant to SALB and SF (CIHR Training Program in Neurodegenerative Lipidomics, TGF 9121), and infrastructure support from the Canadian Foundation Innovation and Ontario Innovation Trust to SF. SI received an Ontario Graduate Scholarship in Science and Technology with contributions from the Parkinson Research Consortium. NV receives an Institute of Aging and CIHR Training Program in Neurodegenerative Lipidomics post-professional fellowship. We gratefully acknowledge the educational software and technical support provided by AutoDesk Research.

<ol>
	<li>Kempermann, G., Jessberger, S., Steiner, B., Kronenberg, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Milestones+of+neuronal+development+in+the+adult+hippocampus.">Milestones of neuronal development in the adult hippocampus.</a> Trends Neurosci. 27, 447-452 (2004).</li><li>Campos, L. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurospheres:+insights+into+neural+stem+cell+biology.">Neurospheres: insights into neural stem cell biology.</a> J Neurosci Res. 78, 761-769 (2004).</li><li>Imbeault, 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+extracellular+matrix+controls+gap+junction+protein+expression+and+function+in+postnatal+hippocampal+neural+progenitor+cells.">The extracellular matrix controls gap junction protein expression and function in postnatal hippocampal neural progenitor cells.</a> BMC Neurosci. 10, 13-13 (2009).</li></ol>

All experiments on animals were performed in accordance with the guidelines and regulations set forth by the University of Ottawa Animal Care Committee and the Canadian Council on Animal Care.

This protocol describes a procedure to culture and serially cryosection post-natal hippocampal NPCs, localize protein expression by immunodetection, and finally reconstruct and analyze the topographical position of immunopositive cells within the entire 3D neurosphere. By combining cell biology culture and processing techniques, microscopy imaging (OpenLab, Improvision and other image analysis softwares), graphic editing software capacities (Adobe Photoshop), and 3D animation and compositing software capacities (Autodesk Maya), we present a methodology to reconstruct the entire cellular composition of 3D cultures from serial 2D images allowing for the faithful reconstruction of cellular position and protein expression throughout a neurosphere culture. This protocol can be combined with equal effectiveness to the registration and reconstruction of epifluorescent thin serial sections or confocal Z-stacks through thicker serial sections. Because clonal expansion of single NPCs in neurosphere culture recapitulates many of the stages observed over the course of neurogenesis and gliogenesis in post-natal brain, the impact of its 3D structure represents an important NPC fate determinant in progeny exposed to the same experimental milieu1. Divergence in lineage and protein expression at the core and periphery of serial neurosphere sections suggests that multiple physical factors including cell position, mechanical stress, and shear force play important roles in regulating NPC biology2. Moreover, connexin protein expression, analyzed here, has been shown to change depending upon when NPCs are cultured as 3D neurospheres in suspension or plated on a laminin substrate with functional connexin-mediated communication altered whether cells are cultured on plastic and substrate or in 3D free-floating cultures3. The impact of cellular position on NPC fate remains unclear. It is technically challenging to analyze impact of spatial location within 3D culture on NPC biology given that antigenic assessment of lineage and signalling proteins requires disruption of the 3D architecture to enable cell permeabilization and antibody access to all cells. Here, we show that a hybrid visualization methodology provides a means of determining whether certain proteins exhibit unique positional localizations in 3D culture, can be used to infer and test protein function and regulation with respect to regional localization within the neurosphere, and, perhaps most importantly, provides the positional data required to study the impact of 3D topography and cellular positioning on NPC fate in 3D culture.

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<td>Euthansol</td>
<td>Reagent</td>
<td>Schering-Plough Canada Inc.</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
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<td>Krazy Glue</td>
<td>Reagent</td>
<td>Home Hardware</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
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<td>VT1000S vibratome</td>
<td>Equipment</td>
<td>Leica Microsystems</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Neural protease</td>
<td>Reagent</td>
<td>Sigma</td>
<td>P6141</td>
<td>Stock solutions stored at -20&deg;C</td>
</tr>
<tr>
<td>Papain</td>
<td>Reagent</td>
<td>Sigma</td>
<td>P4762</td>
<td>Stock solutions stored at -20&deg;C</td>
</tr>
<tr>
<td>DNAse I</td>
<td>Reagent</td>
<td>Roche</td>
<td>11 284 932 001</td>
<td>Stock solutions stored at -20&deg;C</td>
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<tr>
<td>MZ6 Dissecting Microscope</td>
<td>Equipment</td>
<td>Leica Microsytems</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
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<td>ProBlot 6 Hybridization Oven</td>
<td>Equipment</td>
<td>Labnet via Mandel Scientific</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
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<td>Eppendorf</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
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<td>kPBS</td>
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<td>BioShop</td>
<td>PBS404</td>
<td>&nbsp;</td>
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<td>B27 Supplement</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>17504-044</td>
<td>&nbsp;</td>
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<td>Ultra Low Binding Tissue Culture Dishes</td>
<td>Disposable</td>
<td>Corning</td>
<td>3261</td>
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<td>Human Epidermal growth Factor</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>13247-051</td>
<td>Stock solutions stored at -20&deg;C</td>
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<td>Fibroblast growth factor-2</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>13256-029</td>
<td>Also known as basic fibroblast growth factor (bFGF) Stock solutions stored at -20&deg;C</td>
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<td>37% formaldehyde (molecular grade)</td>
<td>Reagent</td>
<td>Sigma</td>
<td>F8775</td>
<td>&nbsp;</td>
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<td>Belly Dancer Shaker</td>
<td>Equipment</td>
<td>Stovall</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
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<td>Tissue- Tek Cryomold</td>
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<td>4566</td>
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<td>Tissue-Tek OCT compound</td>
<td>Reagent</td>
<td>Sakura</td>
<td>4583</td>
<td>&nbsp;</td>
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<td>Whatman Grade 703 Blotting Paper</td>
<td>Disposable</td>
<td>VWR</td>
<td>28298-020</td>
<td>&nbsp;</td>
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<td>CM1900 Cryostat</td>
<td>Equipment</td>
<td>Leica</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
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<td>Polyclonal Anti-Cx29 Primary Antibody</td>
<td>Reagent</td>
<td>Kindly provided by Dr David Paul, Harvard Medical School</td>
<td>&nbsp;</td>
<td>Stored 1:1 in glycerol at -20&deg;C</td>
</tr>
<tr>
<td>Cy3-conjugated donkey anti-rabbit IgG</td>
<td>Reagent</td>
<td>Jackson ImmunoResearch</td>
<td>&nbsp;</td>
<td>Stored 1:1 in glycerol at -20&deg;C</td>
</tr>
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<td>Hoechst 33258</td>
<td>Reagent</td>
<td>Sigma</td>
<td>861405</td>
<td>&nbsp;</td>
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<td>DMRA2 epiflourescent microscope, Orca ER camera, OpenLab v3.56</td>
<td>Equipment/ Software</td>
<td>Leica Hamamatsu Improvision/Perkin Elmer</td>
<td>&nbsp;</td>
<td>This protocol can be performed with any epifluorescent or confocal microscope.</td>
</tr>
<tr>
<td>Photoshop CS4</td>
<td>Software</td>
<td>Adobe</td>
<td>&nbsp;</td>
<td>Graphic software</td>
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<tr>
<td>Maya v10</td>
<td>Software</td>
<td>Autodesk</td>
<td>&nbsp;</td>
<td>Modeling software</td>
</tr>
<tr>
<td>Computer</td>
<td>Equipment</td>
<td>Processor: Intel Corei7 920 Memory: 12GB DDR3 Video card: Nvidia GTX 285 (1GB RAM)</td>
<td>&nbsp;</td>
<td>Modeling hardware</td>
</tr>		</tbody>
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			* All other standard chemical reagents listed in the protocol are from Sigma-Aldrich. All other standard tissue culture reagents are from Invitrogen.		</div>

localizing protein in 3d neural stem cell culture: a hybrid visualization methodology

The importance of 3-dimensional (3D) topography in influencing neural stem and progenitor cell (NPC) phenotype is widely acknowledged yet challenging to study. When dissociated from embryonic or post-natal brain, single NPCs will proliferate in suspension to form neurospheres. Daughter cells within these cultures spontaneously adopt distinct developmental lineages (neurons, oligodendrocytes, and astrocytes) over the course of expansion despite being exposed to the same extracellular milieu. This progression recapitulates many of the stages observed over the course of neurogenesis and gliogenesis in post-natal brain and is often used to study basic NPC biology within a controlled environment. Assessing the full impact of 3D topography and cellular positioning within these cultures on NPC fate is, however, difficult. To localize target proteins and identify NPC lineages by immunocytochemistry, free-floating neurospheres must be plated on a substrate or serially sectioned. This processing is required to ensure equivalent cell permeabilization and antibody access throughout the sphere. As a result, 2D epifluorescent images of cryosections or confocal reconstructions of 3D Z-stacks can only provide spatial information about cell position within discrete physical or digital 3D slices and do not visualize cellular position in the intact sphere. Here, to reiterate the topography of the neurosphere culture and permit spatial analysis of protein expression throughout the entire culture, we present a protocol for isolation, expansion, and serial sectioning of post-natal hippocampal neurospheres suitable for epifluorescent or confocal immunodetection of target proteins. Connexin29 (Cx29) is analyzed as an example. Next, using a hybrid of graphic editing and 3D modelling softwares rigorously applied to maintain biological detail, we describe how to re-assemble the 3D structural positioning of these images and digitally map labelled cells within the complete neurosphere. This methodology enables visualization and analysis of the cellular position of target proteins and cells throughout the entire 3D culture topography and will facilitate a more detailed analysis of the spatial relationships between cells over the course of neurogenesis and gliogenesis in vitro.
Both Imbeault and Valenzuela contributed equally and should be considered joint first authors.

Watch this Scientific Journal Video about Localizing Protein in 3D Neural Stem Cell Culture: a Hybrid Visualization Methodology at JoVE.com

Localizing Protein in 3D Neural Stem Cell Culture: a Hybrid Visualization Methodology

Here, we describe how to produce, expand, and immunolabel postnatal hippocampal neural progenitor cells (NPCs) in three-dimensional (3D) culture. Next, using hybrid visualization technologies, we demonstrate how digital images of immunolabelled cryosections can be used to reconstruct and map the spatial position of immunopositive cells throughout the entire 3D neurosphere.

The importance of 3-dimensional (3D) topography in influencing neural stem and progenitor cell (NPC) phenotype is widely acknowledged yet challenging to ...

localizing-protein-3d-neural-stem-cell-culture-hybrid-visualization

Research

JoVE Journal

Neuroscience

12.6K Görüntüleme.  University of Ottawa. Burada, üç boyutlu (3D) kültür üretmek genişletmek ve immunolabel postnatal hipokampal nöral progenitör hücrelerin (NPC) nasıl açıklar. Sonra, hibrid görselleştirme teknolojiler kullanılarak, dijital görüntüler immunolabelled cryosections tüm 3D neurosphere boyunca immünopozitif hücreler mekansal konumunu yeniden ve harita için nasıl kullanılabileceğini göstermektedir.

Video: Localizing Protein in 3D Neural Stem Cell Culture: a Hybrid Visualization Methodology

Dissection and Culture of Commissural Neurons from Embryonic Spinal Cord

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

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

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

Growth and Differentiation of Adult Hippocampal Arctic Ground Squirrel Neural Stem Cells

Arctic ground squirrels (Urocitellus parryii, AGS) are unique in their ability to hibernate with a core body temperature near or below freezing 1. These animals also resist ischemic injury to the brain in vivo 2,3 and oxygen-glucose deprivation in vitro 4,5. These unique qualities provided the impetus to isolate AGS neurons to examine inherent neuronal characteristics that could account for the capacity of AGS neurons to resist injury and cell death caused by ischemia and extremely cold temperatures. Identifying proteins or gene targets that allow for the distinctive properties of these cells could aid in the discovery of effective therapies for a number of ischemic indications and for the study of cold tolerance. Adult AGS hippocampus contains neural stem cells that continue to proliferate, allowing for easy expansion of these stem cells in culture. We describe here methods by which researchers can utilize these stem cells and differentiated neurons for any number of purposes. By closely following these steps the AGS neural stem cells can be expanded through two passages or more and then differentiated to a culture high in TUJ1-positive neurons (~50%) without utilizing toxic chemicals to minimize the number of dividing cells. Ischemia induces neurogenesis 6 and neurogenesis which proceeds via MEK/ERK and PI3K/Akt survival signaling pathways contributes to ischemia resistance in vivo7 and in vitro 8 (Kelleher-Anderson, Drew et al., in preparation). Further characterization of these unique neural cells can advance on many fronts, using some or all of these methods.

Neural stem cells were prepared from the hippocampus of adult non-hibernating yearling Arctic ground squirrels (AGS). These neural stem cells can be expanded through numerous passages, differentiated and maintained as a nearly 50:50 neuron to glial culture.

Arctic ground squirrels (Urocitellus parryii, AGS) are unique in their ability to hibernate with a core body temperature near or below freezing 1. These ...

Establishing Embryonic Mouse Neural Stem Cell Culture Using the Neurosphere Assay

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

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

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

Neural-Colony Forming Cell Assay: An Assay To Discriminate Bona Fide Neural Stem Cells from Neural Progenitor Cells

The neurosphere assay (NSA) is one of the most frequently used methods to isolate, expand and also calculate the frequency of neural stem cells (NSCs). Furthermore, this serum-free culture system has also been employed to expand stem cells and determine their frequency from a variety of tumors and normal tissues. It has been shown recently that a one-to-one relationship does not exist between neurosphere formation and NSCs. This suggests that the NSA as currently applied, overestimates the frequency of NSCs in a mixed population of neural precursor cells isolated from both the embryonic and adult mammalian brain. This video practically demonstrates a novel collagen based semi- solid assay, the neural-colony forming cell assay (N-CFCA), which has the ability to discriminate stem from progenitor cells based on their long-term proliferative potential, and thus provides a method to enumerate NSC frequency. In the N-CFCA, colonies &ge;2 mm in diameter are derived from cells that meet all the functional criteria of a NSC, while colonies &lt; 2mm are derived from progenitors. The N-CFCA procedure can be used for cells prepared from different sources including primary and cultured adult or embryonic mouse CNS cells. Here we use cells prepared from passage one neurospheres generated from embryonic day 14 mice brain to perform N-CFCA. The cultures are replenished with proliferation medium every seven days for three weeks to allow the plated cells to exhibit their full proliferative potential and then the frequency of neural progenitor and bona fide neural stem cells is calculated respectively by counting the number of colonies that are &lt; 2mm and the ones that are &ge;2mm in reference to the number of cells that were initially plated.

This video protocol demonstrates how to discriminate and enumerate bona fide neural stem cells in a mixed population of neural precursor cells using the neural colony-forming cell assay.

The neurosphere assay (NSA) is one of the most frequently used methods to isolate, expand and also calculate the frequency of neural stem cells (NSCs). ...

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 ...

Enumeration of Neural Stem Cells Using Clonal Assays

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

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

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

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

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

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

Degenerative retinal diseases such as age-related macular degeneration (AMD) are the leading cause of irreversible vision loss worldwide. AMD is ...

Simple Generation of a High Yield Culture of Induced Neurons from Human Adult Skin Fibroblasts

Induced neurons (iNs), the product of somatic cells directly converted to neurons, are a way to obtain patient-derived neurons from tissue that is easily accessible. Through this route, mature neurons can be obtained in a matter of a few weeks. Here, we describe a straightforward and rapid one-step protocol to obtain iNs from dermal fibroblasts obtained through biopsy samples from adult human donors. We explain each step of the process, including the maintenance of the dermal fibroblasts, the freezing procedure to build a stock of the cell line, seeding of the cells for reprogramming, as well as the culture conditions during the conversion process. In addition, we describe the preparation of glass coverslips for electrophysiological recordings, long-term coating conditions, and fluorescence activated cell sorting (FACS). We also illustrate examples of the results to be expected. The protocol described here is easy to perform and can be applied to human fibroblasts derived from human skin biopsies from patients with various different diagnoses and ages. This protocol generates a sufficient amount of iNs which can be used for a wide array of biomedical applications, including disease modeling, drug screening, and target validation.

Direct neuronal reprogramming generates neurons that maintain the age of the starting somatic cell. Here, we describe a single vector-based method to generate induced neurons from dermal fibroblasts obtained from adult human donors.

Induced neurons (iNs), the product of somatic cells directly converted to neurons, are a way to obtain patient-derived neurons from tissue that is easily ...