This research was supported [in part] by the Intramural Research Program of the NIH, National Institute of Environmental Health Sciences. Special thanks to Shyamal Peddada for statistical analysis. We also wish to thank Humphrey Yao, Gary Bird, and Yuki Arao for review of this manuscript, and Franco DeMayo for his continued support and advice.

All operations were done as part of the normal operation of the NIEHS Knock Out Mouse Core facility. All mice were kept on a 12:12 h light:dark cycle, and were feed a diet of NIH-31 and water ad libitum. All experiments were performed in accordance with the Animal Care and Use Committee of the National Institute of Environmental Health Sciences.
1. Animal Preparation
<ol>
	<li>Breed donor mice, B6(Cg)-Tyr&#60;c-2J&#62;/J female mice at 8 - 10 weeks of age naturally to B6(Cg)-Tyr&#60;c-2J&#62;/J male mice between 8 and 26 weeks of age. Check plugs visually the following morning (E0.5).</li>
	<li>Breed recipient mice, Swiss Webster female mice between 6 and 9 weeks of age are naturally bred to vasectomized Swiss Webster male mice. Check plugs visually the following morning (E0.5).</li>
</ol>
2. ES Cell Preparation
<ol>
	<li>For 129-derieved AB2.2 ES cells, culture cells in DMEM supplemented with 15% FBS, 1% Glutamine, 1% Penn/strep, and 0.1% &#946;-mercaptoethanol. Culture all other ES cells per ES cell supplier&#39;s instructions, using their recommended protocols.</li>
</ol>
3. Embryo Collection
<ol>
	<li>Animal Dissection
	<ol>
		<li>Prepare several 60 mm dishes, approximately 1 per 5 mice plus 3 extra, with 10 mL blast collection media (BCM) (10% FBS IN DMEM), and one 4 well dish with 0.5 mL BCM per well. Equilibrate at 37 &#176;C, 5% CO2.</li>
		<li>Euthanize B6(Cg)-Tyr&#60;c-2J&#62;/J female mice at E3.5 using CO2 asphyxiation, with a flow rate of 10%.</li>
		<li>After euthanizing, place the mice in the supine position, and wet the abdomen thoroughly with 70% ethanol.</li>
		<li>Make the first incision through the skin only, at the midpoint of the abdomen, making the opening as wide as possible. Next open through the abdominal wall, again making the incision as wide as possible. 
		NOTE: Doing this in two steps helps reduce or eliminate fur contamination.</li>
		<li>Starting at an ovary, and holding the fat pad of the ovary with blunt forceps, carefully remove the ovary, oviduct, and uterus, taking extra care to keep the adipose tissue to a minimum. Remove the uterus as one single unit, or as individual horns, with no change in the following procedure.</li>
		<li>After removal, place the uterus in a 60 mm dish containing blast collection media.</li>
	</ol>
	</li>
	<li>Embryo Removal
	<ol>
		<li>Prepare a 10 mL syringe filled with BCM, and fit with a 25 G needle.</li>
		<li>One uterus at a time, remove them from the holding dish of BCM, blot them on a tissue to remove excess blood, and place in a 60 mm dish under a low magnification dissecting microscope.</li>
		<li>While carefully and gently holding the uterus just below the distal end (near the oviduct) with dissecting forceps, insert the needle in to the center of the uterus in as parallel a plane as possible. Insert the needle just beyond the tips of the forceps.</li>
		<li>Apply some pressure to the forceps to hold the uterus to the needle, and expel approximately 1 mL of BCM through the horn of the uterus. 
		NOTE: Care must be taken at this step, as too much pressure on the syringe will cause an uncontrollable stream of media, often leaving the dish.</li>
		<li>After flushing the uterus, up to 5 whole uteri per 60 mm dish, place the dish back in the incubator until collection.</li>
	</ol>
	</li>
	<li>Embryo Collection
	<ol>
		<li>Using a hand drawn glass pipette and a mouth pipette apparatus, collect blastocysts under a dissecting scope, set between 25X and 35X. (Figure 1). 
		NOTE: Mouth pipette apparatus consists of 30 - 40 cm of flexible tubing, under 5 mm I.D. Insert a 1, 000 &#181;L pipette tip, point first in to one end, and affix the glass pipette in it. Add a syringe filter to the other end, with an attached 1 cc syringe barrel, no plunger, to act as a mouth piece.</li>
		<li>Removing dishes from the incubator, and using a grid pattern, examine every part of the dish for embryos. Embryos are picked up individually and place on the drop of BCM in a secondary dish.</li>
		<li>After collecting from all dishes, wash the embryos once more in a drop of fresh BCM, and then place in the 4 well dish to await injection.</li>
	</ol>
	</li>
</ol>
4. Embryo Injection
<ol>
	<li>Pick up ES cells individually with the injection needle based on confirmation.
	<ol>
		<li>Prepare an injection dish by adding 5 - 7 mL of injection media (DMEM, 10% FBS and 20 mM HEPES) to a glass bottom injection dish. Injections are done at room temperature.</li>
		<li>Using either an air or oil microinjector, apply vacuum to the injection needle to draw ES cells in. Take care to keep as little space as possible between cells. Count the ES cells here, or at the injection step.</li>
		<li>Select ES cells that are medium to small in size compared to the general population of cells, with a smooth surface, and without obvious defects such as vacuoles. 
		NOTE: ES Cell populations vary greatly in morphological quality, and the standards used will need to adjust with them.</li>
	</ol>
	</li>
	<li>Inject embryos with approximately 15 ES cells (Figure 1).
	<ol>
		<li>Attach a holding pipette tip to a second air microinjector, and position an embryo near the opening of the holder. Apply vacuum to secure the embryo to the holder.</li>
		<li>Adjust for the z axis by moving the holding pipette up or down so that the embryo is just touching the slide, followed by fine focusing on the zona. Next, adjust the Z axis of the injection needle so that ES cells near the tip are in focus.</li>
		<li>Adjust the embryo now by gently pushing from the injection needle at the top or bottom, rotating it to put the ICM in the desired position.</li>
		<li>Insert the injection needle through the zona, and either the ICM or the trophoblast, using a firm but controlled push. Apply a slight pressure to the microinjector of the injection needle to help keep the blastocoel from collapsing.</li>
		<li>Once the needle has penetrated the blastocoel, apply pressure from the microinjector to transfer ES cells to the blastocoel of the embryo. Pause briefly as the bevel of the needle starts to exit the embryo to allow the pressure in the embryo to return to normal, while still retaining the cells. 
		NOTE: Reference group ES cells were injected normally, following a traditional ES cell injection protocol9, taking care not to touch the ICM. ES cells were also injected through the ICM, pushing the needle directly through the ICM (TICM) (Figure 2, Supplemental movie).</li>
	</ol>
	</li>
</ol>
5. Transfer of eEmbryos
<ol>
	<li>Transfer embryos to Swiss Webster mice at E2.5, using a non-surgical embryo transfer device, per the manufacture&#39;s procedures. This non-surgical procedure requires no anesthesia or special post-op care. House mice individually after the transfer of embryos, and through delivery and subsequent weaning.</li>
</ol>

<ol>
	<li>Cong, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiplex+Genome+Engineering+Using+CRISPR/Cas+Systems.">Multiplex Genome Engineering Using CRISPR/Cas Systems.</a> Science. 339 (6), 819-823 (2013).</li><li>Mali, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RNA-guided+human+genome+engineering+via+Cas9.">RNA-guided human genome engineering via Cas9.</a> Science. 339 (6), 823-826 (2013).</li><li>Friedel, R., Seisenberger, C., Kaloff, C., Wurst, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EUCOMM+the+European+Conditional+Mouse+Mutagenesis+Program.">EUCOMM the European Conditional Mouse Mutagenesis Program.</a> Brief Funct Genomic Proteomic. 6 (3), 180-185 (2007).</li><li>Austin, C. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+knockout+mouse+project.">The knockout mouse project.</a> Nat Genet. 36 (9), 921-924 (2004).</li><li>Coleman, J. L., Brennan, K., Ngo, T., Balaji, P., Graham, R. M., Smith, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+Knockout+and+Reporter+Mouse+Line+Generation+and+Breeding+Colony+Establishment+Using+EUCOMM+Conditional-Ready+Embryonic+Stem+Cells:+A+Case+Study.">Rapid Knockout and Reporter Mouse Line Generation and Breeding Colony Establishment Using EUCOMM Conditional-Ready Embryonic Stem Cells: A Case Study.</a> Front Endocrinol (Lausanne). 30, 105 (2015).</li><li>Nagy, A., Rossant, J., Nagy, R., Abramow-Newerly, W., Roder, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Derivation+of+completely+cell+culture-derived+mice+from+early-passage+embryonic+stem+cells.">Derivation of completely cell culture-derived mice from early-passage embryonic stem cells.</a> Proc Natl Acad Sci U S A. 90 (18), 8424-8428 (1993).</li><li>Eggan, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Male+and+female+mice+derived+from+the+same+embryonic+stem+cell+clone+by+tetraploid+embryo+complementation.">Male and female mice derived from the same embryonic stem cell clone by tetraploid embryo complementation.</a> Nat Biotechnol. 20 (5), 455-459 (2002).</li><li>Eggan, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hybrid+vigor,+fetal+overgrowth,+and+viability+of+mice+derived+by+nuclear+cloning+and+tetraploid+embryo+complementation.">Hybrid vigor, fetal overgrowth, and viability of mice derived by nuclear cloning and tetraploid embryo complementation.</a> Proc Natl Acad Sci U S A. 98 (11), 6209-6214 (2001).</li><li>Eakin, G. S., Hadjantonakis, A. K., Papaioannou, V. E., Behringer, R. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Developmental+potential+and+behavior+of+tetraploid+cells+in+the+mouse+embryo.">Developmental potential and behavior of tetraploid cells in the mouse embryo.</a> Dev Biol. 288 (1), 150-159 (2005).</li><li>Huang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+production+of+mice+from+embryonic+stem+cells+injected+into+four-+or+eight-cell+embryos+by+piezo+micromanipulation.">Efficient production of mice from embryonic stem cells injected into four- or eight-cell embryos by piezo micromanipulation.</a> Stem Cells. 26 (7), 1883-1890 (2008).</li><li>Poueymirou, W. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=F0+generation+mice+fully+derived+from+gene-targeted+embryonic+stem+cells+allowing+immediate+phenotypic+analyses.">F0 generation mice fully derived from gene-targeted embryonic stem cells allowing immediate phenotypic analyses.</a> Nat Biotechnol. 25 (1), 91-99 (2007).</li><li>Behringer, R., Gertsenstein, M., Nagy, K. V., Nagy, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Manipulating the Mouse embryo. , (2014).</li><li>Pease, S., Saunders, T. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Advanced Protocols for Animal Transgenesis. , (2011).</li><li>Young, M. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+mechanical+stimulation+on+the+reprogramming+of+somatic+cells+into+human-induced+pluripotent+stem+cells.">Effects of mechanical stimulation on the reprogramming of somatic cells into human-induced pluripotent stem cells.</a> Stem Cell Res Ther. 8 (1), 139 (2017).</li></ol>

The authors have no competing interests to disclose.

It has long been thought that any disturbance of the ICM could lead to mortality, in fact, current blastocyst microinjection protocols still warn of this12,13. What we have shown here is that microinjection through the ICM is not detrimental to the embryo, and increases the yield of chimeras.
The exact mechanism for this effect has not been identified. However, the mechanical disruption of the ICM, and the accompanying hypoblast, shoul...

For nearly 25 years, the creation of genetically targeted mice has been a slow process, often hampered by a bottleneck at the blastocysts ES cell microinjection stage for the generation of germline transmitting chimeras. Recent advancements, including CRISPR/Cas91,2 targeting in ES cells and high-throughput ES cell generation consortiums like KOMP, have improved the generation/availability of genetically modified ES cells. However, the generation of germline chimeras remains a bottleneck in creating genetically modified mice from these ES cells3,4. High-throughput ES cell generation projects have been plagued by high variability in ES cell quality, which is critical for successful creation of germline chimeras. Additionally, some of the commonly utilized ES cell lines are known for high aneuploidy, and difficult production of germline competent chimeras5.
Many methods have been developed for creating mice with either a higher chimera, or completely ES cell derived mice6,7,8,9,10. While each of these systems has its own merits, they also have their shortcomings. The generation of tetraploid chimeras, while generating 100% ES cell derived mice, is inefficient, and generally limited to outbred lines 5,6. Newer methods of injecting morula can yield high percentage chimeras, approaching 100%, but generally require significant additional equipment (lasers or piezos) and training10,11. In laboratories where these techniques are already in place, this new methodology may not be necessary.
This study&#39;s objective was to find a method that uses common techniques and readily available equipment to increase the rate of chimera generation, increasing the chance of germline transmission of the mutant allele to establish the subsequent mouse colony.

<table>
	<tbody>
		<tr>
			<td>ES Cell injection needle</td>
			<td>Humagen</td>
			<td>MSC-20-0</td>
			<td></td>
		</tr>
		<tr>
			<td>NSET device</td>
			<td>Paratechs</td>
			<td>60010</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>Gibco (life technologies)</td>
			<td>11965-092</td>
			<td></td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>Gibco (life technologies)</td>
			<td>10439-024</td>
			<td>lots should be individually tested for ES Cell compatibility.</td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>Sigma</td>
			<td>H0887</td>
			<td></td>
		</tr>
		<tr>
			<td>b-mercaptoethanol</td>
			<td>Sigma</td>
			<td>M7522</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro manipulator</td>
			<td>Leica</td>
			<td>Micro manipulator</td>
			<td></td>
		</tr>
		<tr>
			<td>micro injector</td>
			<td>Eppendorf AG</td>
			<td>Cell Tram Air 5176</td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope</td>
			<td>Leica</td>
			<td>DM IRB</td>
			<td></td>
		</tr>
		<tr>
			<td>4 well dish</td>
			<td>Thermo Scientific</td>
			<td>176740</td>
			<td></td>
		</tr>
		<tr>
			<td>60 mm dish</td>
			<td>Sarstedt</td>
			<td>83.3901</td>
			<td></td>
		</tr>
		<tr>
			<td>B6(Cg)-Tyr&#60;c-2J&#62;/J</td>
			<td>Jackson Labs, Bar Harbor, Maine, USA</td>
			<td>000058</td>
			<td></td>
		</tr>
		<tr>
			<td>Swiss Webster mice</td>
			<td>Taconic, USA</td>
			<td>Tac:SW</td>
			<td></td>
		</tr>
		<tr>
			<td>Injection Dish</td>
			<td>MatTek Corp.</td>
			<td>P50G-0-30-F</td>
			<td></td>
		</tr>
	</tbody>
</table>

trans-inner cell mass injection of embryonic stem cells leads to higher chimerism rates

In an effort to increase efficiency in the creation of genetically modified mice via ES Cell methodologies, we present an adaptation to the current blastocyst injection protocol. Here we report that a simple rotation of the embryo, and injection through Trans-Inner cell mass (TICM) increased the percentage of chimeric mice from 31% to 50%, with no additional equipment or further specialized training. 26 different inbred clones, and 35 total clones were injected over a period of 9 months. There was no significant difference in either pregnancy rate or recovery rate of embryos between traditional injection techniques and TICM. Therefore, without any major alteration in the injection process and a simple positioning of the blastocyst and injecting through the ICM, releasing the ES cells into the blastocoel cavity can potentially improve the quantity of chimeric production and subsequent germline transmission.

Treating cell-line as the random effect, a mixed effects linear model was used to analyze the data in the software (e.g. SAS (version 9.2)). Each analysis controlled for the number of embryos transferred and the cell line. The second analysis also controlled for the number of pups that survived.
For this study, each ES Cell line and clone was injected both with traditional and TICM techniques, alternating between the two methods...

Watch this Scientific Journal Video about Trans-inner Cell Mass Injection of Embryonic Stem Cells Leads to Higher Chimerism Rates at JoVE.com

Trans-inner Cell Mass Injection of Embryonic Stem Cells Leads to Higher Chimerism Rates

Here we present a protocol to increase chimera production without the use of new equipment. A simple orientation change of the embryo for injection can increase the number of embryos produced, and potentially reduce the timeline to germline transmission.

In an effort to increase efficiency in the creation of genetically modified mice via ES Cell methodologies, we present an adaptation to the current ...

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10.1K Views.  NIEHS/NIH. Here we present a protocol to increase chimera production without the use of new equipment. A simple orientation change of the embryo for injection can increase the number of embryos produced, and potentially reduce the timeline to germline transmission.

Video: Trans-inner Cell Mass Injection of Embryonic Stem Cells Leads to Higher Chimerism Rates

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.

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 ...

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 ...

Embryonic Stem Cell-Derived Endothelial Cells for Treatment of Hindlimb Ischemia

Peripheral arterial disease (PAD) results from narrowing of the peripheral arteries that supply oxygenated blood and nutrients to the legs and feet, This pathology causes symptoms such as intermittent claudication (pain with walking), painful ischemic ulcerations, or even limb-threatening gangrene. It is generally believed that the vascular endothelium, a monolayer of endothelial cells that invests the luminal surface of all blood and lymphatic vessels, plays a dominant role in vascular homeostasis and vascular regeneration. As a result, stem cell-based regeneration of the endothelium may be a promising approach for treating PAD.In this video, we demonstrate the transplantation of embryonic stem cell (ESC)-derived endothelial cells for treatment of unilateral hindimb ischemia as a model of PAD, followed by non-invasive tracking of cell homing and survival by bioluminescence imaging. The specific materials and procedures for cell delivery and imaging will be described. This protocol follows another publication in describing the induction of hindlimb ischemia by Niiyama et al.1

The surgical procedure for delivery of embryonic stem cell-derived endothelial cells to the ischemic hindlimb is demonstrated, with non-invasive tracking by bioluminescence imaging.

Peripheral arterial disease (PAD) results from narrowing of the peripheral arteries that supply oxygenated blood and nutrients to the legs and feet, This ...

Isolation and Derivation of Mouse Embryonic Germinal Cells

The ability of embryonic germinal cells (EG) to differentiate into primordial germinal cells (PGCs) and later into gametes during early developmental stages is a perfect model to address our hypothesis about cancer and infertility. This protocol shows how to isolate primordial germinal cells from developing gonads in 10.5-11.5 days post coitum (dpc) mouse embryos.  Developing gonadal ridges from mouse embryos (C57BL6J) were dissociated by mechanical disruption with collagenase, then plated in a mouse embryo fibroblast feeder layer (MEF-CF1) that was previously mitotically inactivated with mitomycin C in the presence of knockout media and supplemented with Leukemia Inhibitor Factor (LIF), basic Fibroblast Growth Factor (bFGF), and Stem Cell Factor (SCF).  Using these optimized methods for PCG identification, isolation, and establishment of culture conditions permits long term cultures of EG cells for more than 40 days.  The embryonic germinal cell lines showed embryonic phenotype and expression of common used markers of the pluripotent state.  Isolation and derivation of germinal cells in culture provide a tool to understand their development in vitro and offer the opportunity to monitor cumulative damage at genetic and epigenetic levels after exposure to oxidative stress.

The ability of embryonic germinal cells to differentiate into primordial germinal cells during early development stages is a perfect model to address our hypothesis about cancer and infertility. This protocol shows how to isolate primordial germinal cells from developing gonads in 10.5-11.5 days post coitum mouse embryos.

The ability of embryonic germinal cells (EG) to differentiate into primordial germinal cells (PGCs) and later into gametes during early developmental ...

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.

Fate Mapping of Human Embryonic Stem Cells by Teratoma Formation

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.

Human embryonic stem cells (hESCs) have an unlimited capacity for self-renewal, and the ability to differentiate into cells derived from all three ...

Use of LysoTracker to Detect Programmed Cell Death in Embryos and Differentiating Embryonic Stem Cells

Programmed cell death (PCD) occurs in adults to maintain normal tissue homeostasis and during embryological development to shape tissues and organs1,2,6,7. During development, toxic chemicals or genetic alterations can cause an increase in PCD or change PCD patterns resulting in developmental abnormalities and birth defects3-5. To understand the etiology of these defects, the study of embryos can be complemented with in vitro assays that use differentiating embryonic stem (ES) cells.
Apoptosis is a well-studied form of PCD that involves both intrinsic and extrinsic signaling to activate the caspase enzyme cascade. Characteristic cell changes include membrane blebbing, nuclear shrinking, and DNA fragmentation. Other forms of PCD do not involve caspase activation and may be the end-result of prolonged autophagy. Regardless of the PCD pathway, dying cells need to be removed. In adults, the immune cells perform this function, while in embryos, where the immune system has not yet developed, removal occurs by an alternative mechanism. This mechanism involves neighboring cells (called "non-professional phagocytes") taking on a phagocytic role-they recognize the 'eat me' signal on the surface of the dying cell and engulf it8-10. After engulfment, the debris is brought to the lysosome for degradation. Thus regardless of PCD mechanism, an increase in lysosomal activity can be correlated with increased cell death.
To study PCD, a simple assay to visualize lysosomes in thick tissues and multilayer differentiating cultures can be useful. LysoTracker dye is a highly soluble small molecule that is retained in acidic subcellular compartments such as the lysosome11-13. The dye is taken up by diffusion and through the circulation. Since penetration is not a hindrance, visualization of PCD in thick tissues and multi-layer cultures is possible12,13. In contrast, TUNEL (Terminal deoxynucleotidyl transferase dUTP nick end labeling) analysis14, is limited to small samples, histological sections, and monolayer cultures because the procedure requires the entry/permeability of a terminal transferase.
In contrast to Aniline blue, which diffuses and is dissolved by solvents, LysoTracker Red DND-99 is fixable, bright, and stable. Staining can be visualized with standard fluorescent or confocal microscopy in whole-mount or section using aqueous or solvent-based mounting media12,13. Here we describe protocols using this dye to look at PCD in normal and sonic hedgehog null mouse embryos. In addition, we demonstrate analysis of PCD in differentiating ES cell cultures and present a simple quantification method. In summary, LysoTracker staining can be a great complement to other methods of detecting PCD.

We present a simple protocol to visualize regions of programmed cell death (PCD) in mouse embryos and differentiating embryonic stem (ES) cell cultures using a highly soluble dye called LysoTracker.

Programmed cell death (PCD) occurs in adults to maintain normal tissue homeostasis and during embryological development to shape tissues and ...

Induction and Analysis of Epithelial to Mesenchymal Transition

Epithelial to mesenchymal transition (EMT) is essential for proper morphogenesis during development. Misregulation of this process has been implicated as a key event in fibrosis and the progression of carcinomas to a metastatic state. Understanding the processes that underlie EMT is imperative for the early diagnosis and clinical control of these disease states. Reliable induction of EMT in vitro is a useful tool for drug discovery as well as to identify common gene expression signatures for diagnostic purposes. Here we demonstrate a straightforward method for the induction of EMT in a variety of cell types. Methods for the analysis of cells pre- and post-EMT induction by immunocytochemistry are also included. Additionally, we demonstrate the effectiveness of this method through antibody-based array analysis and migration/invasion assays.

A straightforward method is described for the induction of epithelial to mesenchymal transition (EMT) in a variety of cell types. Methods for the analysis of cells in EMT states by immunocytochemistry are included.

Epithelial  to mesenchymal transition (EMT) is essential for proper morphogenesis during  development. Misregulation of this  process has been implicated ...