Nos gustaría dar las gracias a los miembros del laboratorio Lee valiosa para los debates sobre el manuscrito. El trabajo en el laboratorio de Lee fue apoyado por becas de Robertson Investigator Award de la Fundación de Células Madre de Nueva York y de Maryland Stem Cell Research Fund (TEDCO).

1. Preparación de una placa de 96 pocillos <ol><li> Mezclar 1 l de Single Cell Dnase1 a 9 l Single Cell Lysis Solution. </li><li> Ponga la 10 l solución mixta en cada pocillo de placas de 96 pocillos PCR. </li></ol> 2. Extracción hESCs para FACS Purificación <ol><li> Separar Oct4 :: línea celular EGFP ES desde el plato de 60 mm con 1 ml de Accutase durante 20 min, a 37 ° C, la cual se neutralizó con los medios de comunicación ES humana. </li><li> Preparar población de células en 1 ml de tampón FACS y ajustar la celda a 1 x 10 6 células / ml. </li><li> Pasar la muestra de células a través de un tubo con tapa de filtro de células de 35 micras. </li><li> Guarde el tubo en hielo antes de la clasificación de células. </li></ol> 3. Lisis de purificado FACS celda única en cada pocillo de la placa de 96 pocillos <ol><li> Ordene la muestra para células positivas EGFP en un clasificador de células con un operador entrenado. Ponga la única célula en una solución Lysis/DNase1 Single Cell en placas de 96 pocillos PCR. Si es necesario, el 9Placa de 6 pocillos con muestra puede ser almacenada en un -80 ° C congelador menos de un mes. </li><li> Incubar las muestras 5 min a TA durante la lisis celular. </li><li> Añadir 1 l de solución de parada para detener la reacción de lisis. </li><li> Incubar 2 min a TA. </li></ol> 4. Transcripción inversa <ol><li> Añadir en cada una alícuota de 0,5 l de 20 mM SMA-T15, SMA-A. </li><li> Añadir 4 l de tampón 5X, 2 l de DTT, 1 l de la transcriptasa inversa, y 1 l de dNTP a cada pocillo. </li><li> Realizar la transcripción inversa en un termociclador. <ol><li> Establecer el programa térmica a 42 ° C × 90 min e inactivar la transcriptasa inversa a 85 ° C × 5 min. </li></ol></li></ol> 5. Amplificación <ol><li> Añadir 4 l de reactivo ExoSAP-IT a cada muestra invertir transcritas. <ol><li> Incubar las muestras a 37 ° C durante 15 min y 80 ° C durante 15 minutos para inactivar el reactivo ExoSAP-IT. </li></ol></li><li> Prepare la mezcla de reacción de PCR wITH SMA-P2 (2 nM) </li><li> Añadir 10 l de mezcla de reacción de PCR para cada muestra transcripción inversa. </li><li> Realizar la amplificación, que consta de 20 ciclos de desnaturalización (94 ° C durante 30 segundos), recocido (57 ° C durante 30 seg), y extensión (68 ° C durante 10 min). </li></ol> 6. Rendimiento QRT-PCR <ol><li> Añadir 10 l de 2X SYBR Green PCR Master Mix, 1 l de ADNc amplificado, 2 nM primers, y 7 l de agua a cada pocillo. <ol><li> Establecer el programa seguido de 95 ° C durante 3 segundos, 60 ° C durante 30 seg x 40 ciclos. </li></ol></li><li> Lleve a cabo por duplicado de los errores técnicos. </li></ol>

<ol>
	<li>Miyanari, Y., Torres-Padilla, M. E. <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+ground-state+pluripotency+by+allelic+regulation+of+Nanog.">Control of ground-state pluripotency by allelic regulation of Nanog.</a> Nature. 483, 470-473 (2012).</li><li>Leitch, H. 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Los autores no tienen nada que revelar.

Solo gen celular de perfiles podría ser una herramienta importante para predecir la funcionalidad de una sola célula o una población entera. Debido a limitaciones técnicas, todo el análisis de perfiles de genes se ha restringido a los promedios de la población. Se han propuesto variaciones en los patrones y niveles entre las células individuales y las subpoblaciones de expresión de genes para causar una interpretación errónea. Estos aspectos celulares diversos se pueden encontrar en hESCs y su heterogeneidad h...

Poblaciones eucariotas más altas son heterogéneos por lo tanto con el análisis de la población total combinada, a menudo es difícil de interpretar sus características celulares. Las células individuales dentro de una población pueden ser sutilmente diferente, y estas diferencias pueden tener consecuencias importantes para la propiedad y el funcionamiento de toda la población de 1, 2. Especialmente, las células madre embrionarias humanas (hESCs) son conocidos por ser heterogéneo, lo que provoca diferentes niveles de pluripotencia y diversas posibilidades para la especificación de linaje en delicadamente formas distintivas 3, 4. Por ejemplo, diferentes antígenos de superficie celular se pueden utilizar para clasificar las células madre pluripotentes no diferenciadas, 5 y el grupo de Austin Smith propuesto diferentes niveles de la pluripotencia en células madre embrionarias de ratón, sobre la base de su morfología, la propensión diferenciación y la dependencia de la vía de señalización 6. Este fenómeno se planteó la hipótesis de embrión humanolas células madre de la NIC 7. Mientras que los estudios se realizaron en general entre las diferentes líneas de células madre, las células madre no solo individuo, que podría ser muy interesante para analizar los diferentes niveles de la pluripotencia en el nivel de células individuales, lo que potencialmente afecta a su capacidad de diferenciación hacia todos los linajes de células somáticas. Heterogeneidad celular y molecular podría ser dictada por la transcripción de perfiles, que se llama la &#39;transcriptoma de células individuales &quot;y hace hincapié en nuevos enfoques para cuantificar los niveles de expresión de genes 8-10. Para el análisis de los niveles de expresión de genes en células individuales, hemos desarrollado un protocolo sencillo, pero robusto de una sola célula RT-PCR cuantitativa. Se confirmó la eficacia y la viabilidad de nuestro protocolo mediante la comparación de cada mitad de lisados ​​de células individuales, así como diluidos en serie RNAs totales de hESCs, dando como resultado variaciones técnicas mínimas y las diferencias. Además, se utilizó una línea reportero genética para aislar p homogéneaoblación de hESCs utilizando sistema de selección de genes. El vector donante para la orientación locus Oct4 (Oct4-2A-EGFP-PGK-Puro construir) y un par de plásmidos TALEN se utilizaron 11. El vector de donantes y un par de plásmidos Talen se introdujeron en hESCs (H9, WA09) utilizando nuestra nucleofection y protocolo de selección clonal y el mantenimiento de hESCs se realizó sobre la base de nuestro protocolo de rutina 12. Se confirmó esta línea genética reportero expresar EGFP para la expresión OCT4 en OCT4 :: EGFP hESCs. Nuestro resultado demuestra que hESCs individuales (ordenados por OCT4 :: células fuertemente positivas EGFP) mantienen altos niveles de expresión OCT4, pero diferentes niveles de expresión de NANOG. Así, nuestro ensayo de expresión solo gen celular debe ser útil para estudiar las heterogeneidades de la población de células madre pluripotentes.

<table border="0" cellpadding="0" cellspacing="0" width="807">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">96 wll PCR Plate</td>
			<td style="width:123px;">USA scientific</td>
			<td style="width:119px;">1402-8900</td>
			<td style="width:311px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:255px;">Ambion Cell Lysis Kit</td>
			<td style="width:123px;">Life Technologies</td>
			<td align="right" style="width:119px;">4458235</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">SMARTScribe Reverse Transcriptase</td>
			<td style="width:123px;">Clonetech</td>
			<td align="right" style="width:119px;">639536</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">ExoSAP-IT</td>
			<td style="width:123px;">USB</td>
			<td align="right" style="width:119px;">78200</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:255px;">Platinum Taq DNA polymerase High Fidelity</td>
			<td style="width:123px;">Invitrogen</td>
			<td align="right" style="width:119px;">11304</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">10mM dNTP Mix, PCR Grade</td>
			<td style="width:123px;">Invitrogen</td>
			<td align="right" style="width:119px;">18427</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">SYBR Universal 2X Master Mix</td>
			<td style="width:123px;">Kapa biosystem</td>
			<td style="width:119px;">KR0389</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Accutase</td>
			<td>Innovative Cell Tech</td>
			<td>S-1100-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">FACS buffer</td>
			<td style="width:123px;"></td>
			<td style="width:119px;"></td>
			<td>45 ml PBS, 5 ml a-MEM, 100 ul DNase, filter sterilized</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">35 &#956;m cell strainer cap tubes</td>
			<td style="width:123px;">BD Biosciences</td>
			<td align="right" style="width:119px;">352235</td>
			<td></td>
		</tr>
	</tbody>
</table>

profiling individual human embryonic stem cells by quantitative rt-pcr

La heterogeneidad de la población de células madre dificulta la comprensión detallada de la biología de células madre, tales como su propensión hacia la diferenciación de diferentes linajes. Un único ensayo transcriptoma de células puede ser un nuevo enfoque para la disección de la variación individual. Hemos desarrollado el método de QRT-PCR de una sola célula, y confirmado que este método funciona bien en varios perfiles de expresión génica. En el nivel de una sola célula, cada célula madre embrionarias humanas, ordenados por OCT4 :: células positivas EGFP, tiene una alta expresión en OCT4, pero un nivel diferente de expresión NANOG. Nuestro ensayo de expresión solo gen celular debe ser útil para interrogar a las heterogeneidades de la población.

Amplificación de ARN de una sola célula eficiente y robusto Para reducir al mínimo la variación transcripcional entre hESCs, utilizamos OCT4 :: EGFP células madre clon para la purificación FACS. Después de la clasificación Oct4 :: células EGFP positivas en una placa de 96 pocillos, cada célula se lisaron en tampón de lisis y se convierte poli (A) + ARN a ADNc de longitud completa usando SMA-T15 (GACATGTATCCGGATGTTTTTTTTTTTTTTTT) y cebador de anc...

Watch this Scientific Journal Video about Profiling Individual Human Embryonic Stem Cells by Quantitative RT-PCR at JoVE.com

Profiling Individual Human Embryonic Stem Cells by Quantitative RT-PCR

Se necesita ensayo de expresión de un solo gen celular para comprender las heterogeneidades de células madre.

Perfiles de Células Madre Embrionarias Humanas individual por RT-PCR cuantitativa

Heterogeneity of stem cell population hampers detailed understanding of stem cell biology, such as their differentiation propensity toward different ...

profiling-individual-human-embryonic-stem-cells-by-quantitative-rt-pcr

Research

JoVE Journal

Biology

11.5K vistas.  Johns Hopkins University School of Medicine.  Se necesita ensayo de expresión de un solo gen celular para comprender las heterogeneidades de células madre. 

Video: Profiling Individual Human Embryonic Stem Cells by Quantitative RT-PCR

Propagation of Human Embryonic Stem (ES) Cells

Propagation of Human Embryonic Stem ES Cells

Yeah, so I'm Lauren Deon. I'm in charge of the Human Amgen stem cell co facility at MGH. Yeah, so I'm Lauren, I'm in charge of the Human AM stem cell co facility at MGH.So I've been working with human Amgen stem cells for years now since I was a postdoc in George De Lab before, from four, four years. And so right now we have two cell lines, H one and H nine, which are both from Y cell. And so the way we are expanding or maintaining these cells in culture is by, at least the way we are splitting these cells is by using collagenous.So what I usually do is for the first few passage after throwing the cells, I use a technical, the picking colonies. So in this case, I can check under the microscope which colonies are good and differentiate and nice shape, and I will collect only these colonies and I will cut them in few pieces and put them back in, in a fresh flat. And the, the colonies that look kind of differentiate it are just left them alone.The other way to pass the cells is by using trypsin. So I don't use this technique here. I think collagenase is a little bit safer because human being stem cells don't like to be individualized or they don't like to be alone.So if you do trypsin, if you use trypsin for a little bit too long, if you use it for like three to four minutes, which is the way we use strips in for other type of cells, human stem cells will be individualized and most of them will die or just differentiate or will not attach to the myth. So the idea is you have to keep the cells as clumps. You don't want them to be alone in the in, in the flask.So using collagenase, the advantage is to keep cells as plants. Using chipsy, you just select for cells that will survive this very, very harsh process of g opsonization. So these cells are usually very highly proliferative.So you get, you can adapt your cells to this tripsin process. The problem is that you have cells that they behave differently, they go much faster. And one risk is that you can get some commercial abnormality to, to this, to this very high division process.So you say that ization can cause selection of cells in culture for most proliferative cells.Right. More ative and probably also higher survival rates than other cells. So after proliferation, basically culture after proliferation in tripsin, after several passages become a different culture, these different properties.So it's, it's hard to figure out if they are exactly identical. If you do the test, the usual test, let's say you check markers, regular markers of end differentiated cells like OC four, nano one 60 SC four C, C3, all this molecule might still be expressed. If you do TER formation, this cells might still differentiate and be formed like al like normal cells.If you look at the karyotype, you might have some abnormality, but you might still have a normal karyotype. The, the, the selective advantage might be due to just a mutation that you cannot see by doing a karyotype. So the fact that they grow much faster is by itself I think a little bit worser.And if we want to use these cells for transplantation at some point, I would definitely not use this type of cells.Okay. So would you like to tell me what are the main technical problems with using this technique for, for passages of cells? So using S, yes.It's just a little bit longer and also it's, since the cells are not going as fast, it's just much longer to get a high number of cells to do some experiment. So it's just less convenient I would say. Would you like to tell me about few words about the goals of your experiment?How do you use CS cells? Okay, so my main project here is to get endothelial cells from human AB stem cells. And the idea is to be able to make blood.And we are working a lot with tissue bioengineering labs and one of their goal is to make tissue in vitro. But one of the limitation to this is the lack of blood vessels going through this tissues. So if we can bring endothelial cells or put endothelial cells in this tissue, we would have better growth of this tissue.So the idea few sources of cells are known for endothelial cells like cold blood or pressure blood, but it would be interesting to have another source of cells like human years. And the advantage is since human years can be expanded and most infinitely, you could modify these cells, make some inducible system and be able to use it. Then in your final product, your material cells, in this case.

Propagación de la madre embrionarias humanas (ES) Células

Investigación

Biología

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.

Derivación de células madre hematopoyéticas de células madre embrionarias murinas

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.

Derivación de células estaminales embrionarias humanas por 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 ...

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.

Sondeo de la actividad mitocondrial complejo en células estaminales embrionarias humanas

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.

Inmunoprecipitación de la cromatina de células estaminales embrionarias humanas

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.

En el etiquetado in vitro de células estaminales embrionarias humanas de Resonancia Magnética

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.

La cultura y el mantenimiento de células estaminales embrionarias humanas

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

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.

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.

Preparación Extienda los cromosomas de las células estaminales embrionarias para cariotipo

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

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.

Congelación y descongelación células estaminales embrionarias humanas

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.

La diferenciación de células madre embrionarias en los precursores de oligodendrocitos

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