EQUIPMENT
<ul>
 <li>Tissue culture incubator, 37&deg;C, 5% CO2</li>
 <li>Centrifuge</li>
 <li>Set of micropipettors (100, 100&mu;L)</li>
 <li>Water bath 37&deg;C</li>
 <li>Water bath 90&deg;C to be source of steam water</li>
 <li>Phase contrast microscope</li>
</ul>
FIRST STEP
Treating the cells with colcemid
In this procedure we used the hESC line H9 cultured onto mouse embryonic fibroblasts (mEF) inactivated with mitomycin C (Sigma) and maintained in DMEM/F12 (Invitrogen) supplemented with 20% knockout serum replacement (KSR, Gibco) and 8ng/mL of fibroblast growth factor (FGF-2, R&amp;D).
In order to obtain a large number of metaphases spreads, it is recommended to use cultures with high mitotic index in which there are many dividing cells.
<ol>
<li>Take the culture flask from the incubator and, in the laminar flow, add Colcemid at a final concentration of 0,1&mu;g/mL.</li>
<li>Return the flask to the incubator and wait 3 hours so the inhibitor can cause mitotic arrest on metaphase, when the chromosomes are well condensed and can be easily visualized under the microscope.</li>
</ol>
Fixing the cells
<ol start="3">
<li>Take out the medium and add tripsin/EDTA 0.05% sufficient to cover the cells surface. Allow cells to incubate for 5 minutes at room temperature and then inactivate the enzyme either by adding culture medium containing serum or by just adding serum to the cells.
 NOTE: It is important to make sure that a single cell suspension is achieved to obtain good metaphase spreads.</li>
<li>Transfer the cells to a 15 mL centrifuge tube and centrifuge at 122 g for 5 minutes.</li>
<li>Discard the supernatant, leaving about 200 mL, and resuspend the pellet gently by tapping the tube, as shown in the video. Make sure the cells are well dissociated, so you can't visualize any clumps in the solution.</li>
<li>Next you will need to add 5 mL of hypotonic solution (KCl 75mM) pre-warmed to 37&deg;C, slowly, by the tube wall as in the following description. First add 3 ml, invert the tube to a horizontal position just to mix the cells with the hypotonic solution then add the remaining 2 ml and keep warm at 37&deg;C for 15 minutes. NOTE: At this point the hypotonic solution will cause an increase on the cellular volume and help to untangle the chromosomes. The time of incubation is important to acquire good chromosome spreads. If the timing is too long, the cell membrane may burst too early and chromosomes are lost. If too short, it may be difficult to obtain chromosome spreads because the cell membrane may not disrupt.</li>
<li>Add 3 drops of the fixative solution (methanol/glacial acetic acid 3:1), invert the tube gently to mix the fixative solution with the cells and centrifuge at 122 g for 5 minutes without break. 
NOTE: The fixative solution should be freshly made. 
NOTE: It is important to use centrifugation without break to avoid cells attrition, preventing loss of the material.</li>
<li>Discard the supernatant, leaving about 200 mL, and resuspend the pellet gently by tapping the bottom of the tube.
 NOTE: Again, make sure the cells are well dissociated, so you can't visualize any clumps in the solution.</li>
<li>Add the first 3 mL of fixative solution, slowly by the tube wall, while you rotate the tube. Invert the tube to a horizontal position just to mix the cells, and then add more 2 mL of the fixative solution by the tube wall to take the cells down. Stock at 4&deg;C overnight.
 NOTE: The fixed cells can be stored in fixative solution for months at 4&deg;C. Besides protecting cells in their swollen state, the fixative solution removes lipids and denatures proteins. These events make the cell membrane fragile and, as a result, make the chromosome spreading easily.</li>
</ol>
CLEANING THE GLASS SLIDES
Before starting making your chromosome spreads make sure that your slides are properly cleaned or you may lose some nuclei and also metaphases. This step is as well important if you want to try any hybridization technique 9.
<ol>
 <li>Place slides in a beaker containing 6M HCl for at least 3 h at room temperature.</li>
 <li>After this time, wash slides in running tap water for 10 minutes.</li>
 <li>Rinse the slides in distilled water and let they dry at room temperature.</li>
 <li>Now the slides can be stored into 96% ethanol and dried with a lint-free immediately prior to use.</li>
</ol>
NOTE: For in situ hybridization methods, the slides cannot be stored for more than 2 days into 96% ethanol
SECOND STEP
Washing the cells
<ol start="10">
<li>On the next day, centrifuge the cells at 122 g for 5 minutes without break.</li>
<li>Discard the supernatant leaving about 200 ml. Resuspend the pellet by gently flicking the tube then add 5 ml of fresh fixative solution (methanol/glacial acetic acid 3:1), slowly by the tube wall while rotating the tube. Repeat this wash step 2 more times for a total of three washes. 
NOTE: The fixative solution should be freshly made.</li>
</ol>
Preparing the slides
<ol start="12">
<li>At the last centrifugation step leave sufficient amount of solution to homogenize the cell pellet and obtain an adequate density of cells in the slides (see figure 1).</li>
<li>Add 20-30 &mu;L of cell suspension onto a clean dry slide by moving the pipette very close and parallel to the surface. As the fixative solution evaporates, the surface of slide becomes grainy.</li>
<li>Immediately, expose the slide, face up, into the steam of hot water (90&deg;) for 30 seconds to cause the cells blow up.
 NOTE: At this moment, the methanol from the fixative solution evaporates, resulting in an increased acetic acid concentration, which together with the water stimulates the chromosome spreading.</li>
<li>Look at a phase contrast microscope just to check if the concentration as well as the cell distribution is good (see figure 1).</li>
<li>Now the slides are ready to be used to check the set of chromosomes by cytogenetics approaches as G-banding (Giemsa), FISH, SKY or CGH.</li>
</ol>
IMPORTANT HINTS
How choose an adequate metaphase to be analyzed
Choosing round and isolated metaphases (figure 2D), you may avoid considering false aneuploidies as the gain of chromosomes generated by two or more spreads mixed together or the loss of chromosomes generated by a launched chromosome. So, avoid choosing metaphases near nuclei because some chromosomes may be hidden by them (figure 2A and 2B). Besides, look for round metaphases and be sure that any chromosome is separated from the metaphase (figure 2C).
Feeder cells and the hESC karyotype
For G-banding and SKY analysis, the presence of feeder cells in hESC culture does not interfere with the results, because feeder cells are not under a dividing state (inactivated by mitomycin C or irradiation) and will not be part of the metaphase population. However, for the application of FISH technique in interphase nuclei, it is preferred to separate the hESC population from feeder cells by harvesting the colonies manually before trypsinization for FISH analysis.
<img border="0" src="/files/ftp_upload/1512/1512fig1tmb.jpg" alt="Figure 1" /> Figure 1: How know the appropriate cell density in the slides. Images of phase contrast microscope in 10x objective. (A) The cell density is too high. The arrows point to metaphase spreads too close of nuclei. (B) A slide with good cell density. The circles show metaphases spreads isolated from nuclei or other metaphases. Please <a href="https://www.jove.com/files/ftp_upload/1512/1512fig1.jpg">click here</a> to see a larger version of figure 1.
<img border="0" src="/files/ftp_upload/1512/1512fig2tmb.jpg" alt="Figure 2" /> Figure 2: How to choose an adequate metaphase to be analysed. Chromosomes are stained with DAPI and the images obtained by a fluorescent microscope in 100x objective. (A) (B) Avoid metaphases near nuclei (indicated by the arrows) (C) and metaphases not round that present chromosomes separated (circle). (D) A round metaphase is a good metaphase to be analysed. Please <a href="https://www.jove.com/files/ftp_upload/1512/1512fig2.jpg">click here</a> to see a larger version of figure 2.

<ol>
	<li>Thomson, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Embryonic+stem+cell+lines+derived+from+human+blastocysts.">Embryonic stem cell lines derived from human blastocysts.</a> Science. 282 (5391), 1145-1145 (1998).</li><li>Draper, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recurrent+gain+of+chromosomes+17q+and+12+in+cultured+human+embryonic+stem+cells.">Recurrent gain of chromosomes 17q and 12 in cultured human embryonic stem cells.</a> Nat Biotechnol. 22 (1), 53-53 (2004).</li><li>Maitra, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genomic+alterations+in+cultured+human+embryonic+stem+cells.">Genomic alterations in cultured human embryonic stem cells.</a> Nat Genet. 37 (10), 1099-1099 (2005).</li><li>Mitalipova, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preserving+the+genetic+integrity+of+human+embryonic+stem+cells.">Preserving the genetic integrity of human embryonic stem cells.</a> Nat Biotechnol. 23 (1), 19-19 (2005).</li><li>Buzzard, J. J., Gough, N. M., Crook, J. M., Colman, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Karyotype+of+human+ES+cells+during+extended+culture.">Karyotype of human ES cells during extended culture.</a> Nat Biotechnol. 22 (4), 381-381 (2004).</li><li>Caisander, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chromosomal+integrity+maintained+in+five+human+embryonic+stem+cell+lines+after+prolonged+in+vitro+culture.">Chromosomal integrity maintained in five human embryonic stem cell lines after prolonged in vitro culture.</a> Chromosome Res. 14 (2), 131-131 (2006).</li><li>Imreh, M. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+culture+conditions+favoring+selection+of+chromosomal+abnormalities+in+human+ES+cells.">In vitro culture conditions favoring selection of chromosomal abnormalities in human ES cells.</a> J Cell Biochem. 99 (2), 508-508 (2006).</li><li>Robin-Wesselschmidt, J. L., Loring, J. F., Robin-Wesselschmidt, J. L., Robin-Wesselschmidt, S. c. h. w. a. r. t. z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Human Stem Cell Manual. , 59-59 (2007).</li><li>Rooney, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Human Cytogenetics. , (2001).</li><li>Heslop-Harrison, P., Schwarzacher, T., Heslop-Harrison, P., Schwarzacher, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Practical in situ hybridization. , 51-51 (2000).</li></ol>

The authors have nothing to disclose.

The preparation of chromosome spreads is a critical step for a successful analysis of the genetic status of embryonic stem cells by routinely techniques as G-banding, and more sophisticated techniques such as FISH, SKY and CGH.
This procedure can be applied for many cell types by varying the period of colcemid incubation, which depends on the cell cycle length. For colonies of embryonic stem cells, we wait 3 hours while for embryoid bodies (EB) this time can be up to 6 hours.
<p class="jov...

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		<th>Material Name</th>
		<th>Type</th>
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		<th>Catalogue Number</th>
		<th>Comment</th>
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<td>15 ml centrifuge tube</td>
<td>&nbsp;</td>
<td>TPP</td>
<td>91015</td>
<td>&nbsp;</td>
<tr>
<td>Colcemid Karyo MAX</td>
<td>&nbsp;</td>
<td>Gibco</td>
<td>15212-012</td>
<td>&nbsp;</td>
<tr>
<td>EDTA</td>
<td>&nbsp;</td>
<td>Isofar</td>
<td>721</td>
<td>&nbsp;</td>
<tr>
<td>Glacial acetic acid</td>
<td>&nbsp;</td>
<td>Isofar</td>
<td>100</td>
<td>&nbsp;</td>
<tr>
<td>Methanol</td>
<td>&nbsp;</td>
<td>Isofar</td>
<td>208</td>
<td>&nbsp;</td>
<tr>
<td>Potassium Chloride (KCl)</td>
<td>&nbsp;</td>
<td>Merck</td>
<td>104.931.000</td>
<td>&nbsp;</td>
<tr>
<td>Slide</td>
<td>&nbsp;</td>
<td>Bioslide</td>
<td>7105-1</td>
<td>&nbsp;</td>
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<td>Tripsin</td>
<td>&nbsp;</td>
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chromosomal spread preparation of human embryonic stem cells for karyotyping

Although human embryonic stem cells (hESC) have been shown to present a stable diploid karyotype 1, many studies have reported that depending on culture conditions they become prone to acquire chromosomal anomalies such as addition of whole or parts of chromosomes. Indeed, during long-term culture, karyotypic alterations are observed when enzymatic or chemical dissociation are used 2,3,4, while manual dissection of colonies for passaging retains a stable karyotype 5. Besides, changes in the environment such as the removal of feeder cells also seem to compromise the genetic integrity of hESC 3,6. Once chromosomal alterations could affect cellular physiology, the characterization of the genetic integrity of hESC in vitro is crucial considering hESC as an essential tool in embryogenesis studies and drug testing. Furthermore, for future therapeutic purposes chromosomal changes are a real concern as it is frequently associated to carcinogenesis.
Here we show a simple and useful method to obtain high quality chromosome spreads for subsequent analysis of chromosome set by G-banding, FISH, SKY or CGH techniques 7,8. We recommend checking the chromosomal status routinely with intervals of 5 passages in order to monitor the appearance of translocations and aneuploidies
Priscila Britto and Rafaela Sartore contributed equally to the paper.

Watch this Scientific Journal Video about Chromosomal Spread Preparation of Human Embryonic Stem Cells for Karyotyping at JoVE.com

Chromosomal Spread Preparation of Human Embryonic Stem Cells for Karyotyping

Karyotyping is a simple and useful technique widely used for detecting genetic alterations. Here we describe a step by step protocol for chromosome spread preparation of human embryonic stem cells for monitoring the chromosomal status of these cells maintained in culture.

Although human embryonic stem cells (hESC) have been shown to present a stable diploid karyotype 1, many studies have reported that depending on culture ...

chromosomal-spread-preparation-human-embryonic-stem-cells-for

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48.6K vues.  Federal University of Rio De Janeiro-UFRJ. Caryotype est une technique simple et utile largement utilisé pour détecter les altérations génétiques. Nous décrivons ici une étape par étape pour la préparation du protocole propagation de chromosomes de cellules souches embryonnaires humaines pour la surveillance du statut chromosomique de ces cellules maintenues en culture.

Vidéo: Chromosomal Spread Preparation of Human Embryonic Stem Cells for Karyotyping

Propagation of Human Embryonic Stem (ES) Cells

Propagation of Human Embryonic Stem ES Cells

Derivation of Hematopoietic Stem Cells from Murine Embryonic Stem Cells

A stem cell is defined as a cell with the capacity to both self-renew and generate multiple differentiated progeny.  Embryonic stem cells (ESC) are derived from the blastocyst of the early embryo and are pluripotent in differentiative ability.  Their vast differentiative potential has made them the focus of much research centered on deducing how to coax them to generate clinically useful cell types.  The successful derivation of hematopoietic stem cells (HSC) from mouse ESC has recently been accomplished and can be visualized in this video protocol.  HSC, arguably the most clinically exploited cell population, are used to treat a myriad of hematopoietic malignancies and disorders.  However, many patients that might benefit from HSC therapy lack access to suitable donors.  ESC could provide an alternative source of HSC for these patients.  The following protocol establishes a baseline from which ESC-HSC can be studied and inform efforts to isolate HSC from human ESC.  In this protocol, ESC are differentiated as embryoid bodies (EBs) for 6 days in commercially available serum pre-screened for optimal hematopoietic differentiation.  EBs are then dissociated and infected with retroviral HoxB4.  Infected EB-derived cells are plated on OP9 stroma, a bone marrow stromal cell line derived from the calvaria of  M-CSF-/- mice, and co-cultured in the presence of hematopoiesis promoting cytokines for ten days.  During this co-culture, the infected cells expand greatly, resulting in the generation a heterogeneous pool of 100s of millions of cells.  These cells can then be used to rescue and reconstitute lethally irradiated mice.

This protocol details the derivation of transplantable hematopoietic stem cells from mouse embryonic stem cells (ESC) and their subsequent injection into lethally irradiated recipient mice. Briefly, ESC are differentiated as embryoid bodies, which are then infected with retroviral HoxB4 and co-cultured with OP9 stromal cells and hematopoietic cytokines.

A stem cell is defined as a cell with the capacity to both self-renew and generate multiple differentiated progeny.  Embryonic stem cells (ESC) are ...

Derivation of Human Embryonic Stem Cells by Immunosurgery

The ability of human embryonic stem cells to self-renew and differentiate into all cell types of 
the body suggests that they hold great promise for both medical applications and as a research 
tool for addressing fundamental questions in development and disease. Here, we provide a 
concise, step-by-step protocol for the derivation of human embryonic stem cells from embryos 
by immunosurgical isolation of the inner cell mass. 


The ability of human embryonic stem cells to self-renew and differentiate into all cell types of 
the body suggests that they hold great promise for both medical applications and as a research 
tool for addressing fundamental questions in development and disease. Here, we provide a 
concise, step-by-step protocol for the derivation of human embryonic stem cells from embryos 
by immunosurgical isolation of the inner cell mass.

The ability of human embryonic stem cells to self-renew and differentiate into all cell types of 
the body suggests that they hold great promise for both ...

Probing for Mitochondrial Complex Activity in Human Embryonic Stem Cells

Mitochondria are cytoplasmic organelles that have a primary role in cellular metabolism and homeostasis, regulation of the cell signaling network, and programmed cell death. Mitochondria produce ATP, regulate the cytoplasmic redox state and Ca2+ balance, catabolize fatty acids, synthesize heme, nucleotides, steroid hormones, amino acids, and help assemble iron-sulfur clusters in proteins. Mitochondria also have an essential role in heat production. Mutations of the mitochondrial genome cause several types of human disorder. The accumulation of mtDNA mutations correlates with aging and is suspected to have an important role in the development of cancer. Due to their vitally important role in all cell types, the function of mitochondria must also be critical for stem cells. Key advances have been made in our understanding of stem cell viability, proliferation, and differentiation capacity. But the functional activity of stem cells, in particular their energy status, was not yet been studied in detail. Almost nothing is known about the mitochondrial properties of human embryonic stem cells (hESCs) and their differentiated precursor progeny. One way to understand and evaluate the role of mitochondria in hESC function and developmental potential is to directly measure the activity of mitochondrial respiratory complexes. Here, we describe high resolution clear native gel electrophoresis and subsequent in gel activity visualization as a method for analyzing the five respiratory chain complexes of hESCs.

In this video, we will show you how the mitochondrial respiratory chain complexes of human embryonic stem cells can be analyzed using in gel activity assays.

Mitochondria are cytoplasmic organelles that have a primary role in cellular metabolism and homeostasis, regulation of the cell signaling network, and ...

Chromatin Immunoprecipitation from Human Embryonic Stem Cells

The functional and structural complexity of the myriad of cells in metazoan organisms arises from a small number of stem cells. Stem cells are characterized by two fundamental properties: self-renewal and multipotency that allows a stem cell to differentiate into virtually any cell type 1. The progression stem cell to differentiated cell is characterized by loss of multipotency, structural and morphological changes and the hierarchic activity of transcription factors and signaling molecules, whose activities establish and maintain cell-type specific gene expression patterns. At the molecular level, cell differentiation involves dynamic changes of the structure and composition of chromatin and the detection of those dynamic changes can provide valuable insights into the functional features of stem cells and the cell differentiation process 2,3. Chromatin is a highly compacted DNA-protein complex that forms when cells package chromosomal DNA with proteins, mainly histones 4. Stemcellness and cell differentiation has been correlated with the presence of specific arrays of regulatory proteins such as epigenetic factors, histone variants, and transcription factors 2,3,5.
 Chromatin immunoprecipitation (ChIP) provides a valuable method to monitor the presence of RNA, proteins, and protein modifications in chromatin 6,7. The comparison of chromatin from different cell types can elucidate dynamic changes in protein-chromatin associations that occur during cell differentiation.
Chromatin immunoprecipitation involves the purification of in vivo cross-linked chromatin. The isolated chromatin is reduced to smaller fragments by enzymatic digestion or mechanical force. Chromatin fragments are precipitated using specific antibodies to target proteins or protein and DNA modifications. The precipitated DNA or RNA is purified and used as a template for PCR or DNA microarray based assays. Prerequisites for a successful ChIP are high quality antibodies to the desired antigen and the availability of chromatin from control cells that do not express the target molecule. ChIP can correlate the presence of proteins, protein and RNA modifications, and RNA with specific target DNA, and depending on the choice of outread tool, detects the association of target molecules at specific target genes or in the context of an entire genome. The comparison of the distribution of proteins in the chromatin of differentiating cells can elucidate the dynamic changes of chromatin composition that coincide with the progression of cells along a cell lineage.

The differentiation of ESC coincides with cell-type specific changes in the structure and composition of chromatin. The detection of those changes provides valuable insights into the mechanisms that define stemcellness and cell differentiation. Chromatin immunoprecipitation (ChIP) represents a valuable method to dissect the molecular mechanisms underlying stem cell differentiation.

The functional and structural complexity of the myriad of cells in metazoan organisms arises from a small number of stem cells. Stem cells are ...

In vitro Labeling of Human Embryonic Stem Cells for Magnetic Resonance Imaging

Human embryonic stem cells (hESC) have demonstrated the ability to restore the injured myocardium. Magnetic resonance imaging (MRI) has emerged as one of the predominant imaging modalities to assess the restoration of the injured myocardium. Furthermore, ex-vivo labeling agents, such as iron-oxide nanoparticles, have been employed to track and localize the transplanted stem cells. However, this method does not monitor a fundamental cellular biology property regarding the viability of transplanted cells. It has been known that manganese chloride (MnCl2) enters the cells via voltage-gated calcium (Ca2+) channels when the cells are biologically active, and accumulates intracellularly to generate T1 shortening effect. Therefore, we suggest that manganese-guided MRI can be useful to monitor cell viability after the transplantation of hESC into the myocardium.
In this video, we will show how to label hESC with MnCl2 and how those cells can be clearly seen by using MRI in vitro. At the same time, biological activity of Ca2+-channels will be modulated utilizing both Ca2+-channel agonist and antagonist to evaluate concomitant signal changes.

In this video, we are showing how to label human embryonic stem cells (hESC) with manganese chloride (MnCl2) which can enter cells via voltage-gated calcium channels when the cells are biologically active. Additionally, we show the use of MnCl2 as cellular MRI contrast agent to determine the in vitro viability of hESC.

Human embryonic stem cells (hESC) have demonstrated the ability to restore the injured myocardium. Magnetic resonance imaging (MRI) has emerged as one of ...

Culture and Maintenance of Human Embryonic Stem Cells  

Human embryonic stem (hES) cells must be monitored and cared for in order to maintain healthy, undifferentiated cultures. At minimum, the cultures must be  fed  every day by performing a complete medium change to replenish lost nutrients and to keep the cultures free of unwanted differentiation factors. Although a small amount of differentiation is normal and expected in stem cell cultures, the culture should be routinely cleaned up by manually removing, or "picking" differentiated areas. Identifying and removing excess differentiation from hES cell cultures are essential techniques in the maintenance of a healthy population of cells.

Culture and Maintenance of Human Embryonic Stem Cells

This protocol demonstrates how to maintain healthy, undifferentiated human embryonic stem (ES) cells.

Human embryonic stem (hES) cells must be monitored and cared for in order to maintain healthy, undifferentiated cultures. At minimum, the cultures must be ...

Freezing and Thawing Human Embryonic Stem Cells

Since James Thomson et al developed a technique in 1998 to isolate and grow hES in culture, freezing cells for later use and thawing and expanding cells from a frozen stock have become important procedures performed in routine hES cell culture. Since hES cells are very sensitive to the stresses of freezing and thawing, special care must taken. Here we demonstrate the proper technique for rapidly thawing hES cells from liquid nitrogen stocks, plating them on mouse embryonic feeder cells, and slowly freezing them for long-term storage.

Since James Thomson et al developed a technique in 1998 to isolate and grow hES in culture, freezing cells for later use and thawing and expanding cells from a frozen stock have become important procedures performed in routine hES cell culture. Since hES cells are very sensitive to the stresses of freezing and thawing, special care must taken. Here we demonstrate the proper technique for rapidly thawing hES cells from liquid nitrogen stocks, plating them on mouse embryonic feeder cells, and slowly freezing them for long-term storage.

Since James Thomson et al developed a technique in 1998 to isolate and grow hES in culture, freezing cells for later use and thawing and expanding cells ...

Differentiation of Embryonic Stem Cells into Oligodendrocyte Precursors

Oligodendrocytes are the myelinating cells of the central nervous system. For regenerative cell therapy in demyelinating diseases, there is significant interest in deriving a pure population of lineage-committed oligodendrocyte precursor cells (OPCs) for transplantation. OPCs are characterized by the activity of the transcription factor Olig2 and surface expression of a proteoglycan NG2. Using the GFP-Olig2 (G-Olig2) mouse embryonic stem cell (mESC) reporter line, we optimized conditions for the differentiation of mESCs into GFP+Olig2+NG2+ OPCs. In our protocol, we first describe the generation of embryoid bodies (EBs) from mESCs. Second, we describe treatment of mESC-derived EBs with small molecules: (1) retinoic acid (RA) and (2) a sonic hedgehog (Shh) agonist purmorphamine (Pur) under defined culture conditions to direct EB differentiation into the oligodendroglial lineage. By this approach, OPCs can be obtained with high efficiency (&gt;80%) in a time period of 30 days. Cells derived from mESCs in this protocol are phenotypically similar to OPCs derived from primary tissue culture. The mESC-derived OPCs do not show the spiking property described for a subpopulation of brain OPCs in situ. To study this electrophysiological property, we describe the generation of spiking mESC-derived OPCs by ectopically expressing NaV1.2 subunit. The spiking and nonspiking cells obtained from this protocol will help advance functional studies on the two subpopulations of OPCs.

We describe a small molecule-based protocol for differentiation of mouse embryonic stem cells into oligodendrocyte precursor cells (OPCs). This protocol generates Olig2+NG2+ OPCs with high efficiency by 30 days of differentiation. We also describe a method to generate "spiking" OPCs that can fire action potentials.

Oligodendrocytes are the myelinating cells of the central nervous system. For regenerative cell therapy in demyelinating diseases, there is significant ...

Fate Mapping of Human Embryonic Stem Cells by Teratoma Formation

Human embryonic stem cells (hESCs) have an unlimited capacity for self-renewal, and the ability to differentiate into cells derived from all three embryonic germ layers (1). Directed differentiation of hESCs into specific cell types has generated much interest in the field of regenerative medicine (e.g., (2-5)), and methods for determining the in vivo fate of selected or manipulated hESCs are essential to this endeavor. We have adapted a highly efficient teratoma formation assay for this purpose. A small number of specifically selected hESCs is mixed with undifferentiated wild type hESCs and Phaseolus vulgaris lectin to form a cell pellet. This is grafted beneath the kidney capsule in an immunodeficient mouse. As few as 2.5 x 105 hESCs are needed to form a 16 cm3 teratoma within 8-12 weeks. The fate of the originally selected hESCs can then be determined by immunohistochemistry. This method provides a valuable tool for characterizing tissue-specific reagents for cell-based therapy.

Directed differentiation of hESCs into specific cells has generated much interest in regenerative medicine. We provide a concise, step-by-step protocol for determining the in vivo fate of selected hESCs that provides a valuable tool for characterizing tissue-specific reagents for cell-based therapy.