This work was funded by a New Faculty Award II from the California Institute of Regenerative Medicine (RN2-00921-1), and an NIH-funded National Research Award (F32-HL104924)

1. Preparation of Mouse Embryonic Feeders
<ol>
 <li>The MEFs used in the co-culture of hESCs should be previously treated by irradiation or Mitomycin-C to inhibit the cells from undergoing division.</li>
 <li>Two hours prior to MEF seeding, coat each 60 mm plasma treated culture dish with 2 ml of 0.05% Gelatin.</li>
 <li>Thaw a vial of treated MEFs and plate at ~20,000 cells/cm2.</li>
 <li>Allow the cells to adhere overnight.</li>
</ol>
2. Co-seeding hESCS onto MEFs
<ol>
 <li>New colonies may be initiated from cryopreserved cultures or passaging current cultures onto new MEF-coated dishes, as below.</li>
 <li>Wash the plate containing the large hESC colonies to be passaged 1 time with 3 ml of warmed 1x PBS.</li>
 <li>Add 3 ml of Collagenase IV/PBS solution (1 mg/ml), and incubate for 5-10 min at 37 &deg;C. (Note: The cells will not become distinct or ball up as seen with trypsin).</li>
 <li>While the cells are still in the collagenase, use an edge of a 5 ml pipet tip, create a grid pattern on the colonies, breaking them into small cell clumps.</li>
 <li>Use the end of the pipet tip (held in a perpendicular manner to the culture plate) to scrape the bottom of the culture plate, dislodging all the cells from the surface.</li>
 <li>Collect the cells into a Falcon tube and spin at (1000 rpm) for 5 min.</li>
 <li>After centrifugation, aspirate the medium, leaving the cell pellet in the Falcon tube.</li>
 <li>Aspirate the MEF medium from the MEFs plated the day before.</li>
 <li>Re-plate the cells at a 1:3 ratio from the original plate, and feed with 3 ml of hESC medium</li>
</ol>
3. Depleting MEFs from the Co-culture
Note: Human ESC cultures must be at high density, usually between 10 and 14 days of culture.
<ol>
 <li>Place the tip of an aspirating pipet at the edge of the plate and allow the suction to gently pull up the edge of the MEF sheet.</li>
 <li>Remove the media from the dish, and allow the tip to catch the cell sheet and slowly move the tip in an arced manner above the plate. Note: The sheet may clog in the tip of the pipet, but this is not problematic as it should not prevent the user from manually pulling the sheet from the surface of the culture plate. If the cells are stuck to the end of the aspirator, you can use the top of the culture dish to break up the cell sheet for complete aspiration.</li>
 <li>Replace hESC medium immediately, and put the plate back into the incubator.</li>
</ol>
4. Representative Results
The end result of the MEF removal process produces small undisturbed hESC colonies (Figure 1D) able to undergo significant expansion into very large colonies (Figure 2) while maintaining expression of pluripotency makers SSEA-4, Oct &frac34;, and Tra 1-81 (Figure 3).
<img alt="Figure 1" src="/files/ftp_upload/3951/3951fig1.jpg" /> 
 Figure 1. ESC Colony Morphology Before and After MEF Removal. Human Embryonic Stem Cell Colonies at A) day 1 and B) day 2 after seeding onto culture dishes. C) High Density Human Embryonic Stem Cell Colonies (H7) surrounded by MEFs. The two hESC colonies are outlined in red dashes. D) After MEF removal using the aspiration technique described, we are left with an isolated hESC colony with very few MEFs surrounding the intact colony.
<img alt="Figure 2" src="/files/ftp_upload/3951/3951fig2.jpg" /> 
 Figure 2. ESC Colony Expansion 10 Days After MEF Removal. The original hESC colony immediately after MEF depletion (left) is allowed to expand into a very large colony (right) approximately 800 &mu;m, 10x. Note that the original colony is imaged at the same magnification (10x) as the composite colony.
<img alt="Figure 3" src="/files/ftp_upload/3951/3951fig3.jpg" /> 
 Figure 3. Immunostaining of MEF-depleted hESC colonies. Immunofluorescent identification of colonies up to 10 days after the MEF depletion shows that colonies maintain their expression of pluripotency markers as evident by Oct &frac34;, SSEA-4, and Tra-1-81 staining. Moreover, these hESC colonies do not exhibit differentiation towards a mesodermal fate, indicated by the absence of Flk-1. A, E, I, and M) are transmission light images of the immunoflouscently stained colonies, 20, 10, 10 and 2x, respectively. B, F, J, and N) show the nuclei - DAPI stained cells of the immunofluorescently stained colonies, 20, 10, 10 and 2x, respectively. C-D) show the expression of human stem cell marker SSEA-4 only, and composite image, 20x. G-H) show the expression of human stem cell marker Oct &frac34; only, and composite image, 10x. K-L) show the expression of human stem cell marker Tra 1-81 only, and composite image, 10x. M-P) The last row if images depict a colony portraying the typical smooth borders seen at this magnification, 2x, and these colonies did not express O) Flk-1, an early marker of mesoderm differentiation, nor did they P) contain any fibroblasts as shown by absence of DDR2 staining.
Supplemental Video. Removing Fibroblasts by Sheet Aspiration. <a href="https://www.jove.com/files/ftp_upload/3951/3951movie1.mp4" target="_blank"> Click here to view movie</a>.

<ol>
	<li>Bongso, A., Fong, C. Y., Ng, S. C., Ratnam, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+culture+of+inner+cell+mass+cells+from+human+blastocysts.">Isolation and culture of inner cell mass cells from human blastocysts.</a> Hum. Reprod. 9, 2110-2117 (1994).</li><li>Reubinoff, B. E., Pera, M. F., Fong, C. Y., Trounson, A., Bongso, 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+from+human+blastocysts:+somatic+differentiation+in+vitro.">Embryonic stem cell lines from human blastocysts: somatic differentiation in vitro.</a> Nat. Biotechnol. 18, 399-404 (2000).</li><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, 1145-1147 (1998).</li><li>Thomas, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated,+scalable+culture+of+human+embryonic+stem+cells+in+feeder-free+conditions.">Automated, scalable culture of human embryonic stem cells in feeder-free conditions.</a> Biotechnol Bioeng. 102, 1636-1644 (2009).</li><li>Kolhar, P., Kotamraju, V. R., Hikita, S. T., Clegg, D. O., Ruoslahti, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthetic+surfaces+for+human+embryonic+stem+cell+culture.">Synthetic surfaces for human embryonic stem cell culture.</a> J. Biotechnol. 146, 143-146 (2010).</li><li>Hovatta, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+culture+system+using+human+foreskin+fibroblasts+as+feeder+cells+allows+production+of+human+embryonic+stem+cells.">A culture system using human foreskin fibroblasts as feeder cells allows production of human embryonic stem cells.</a> Hum. Reprod. 18, 1404-1409 (2003).</li><li>McKay, T. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+feeder+cell+line+for+derivation+and+culture+of+hESc/hiPSc.">Human feeder cell line for derivation and culture of hESc/hiPSc.</a> Stem Cell Res. 7, 154-162 (2011).</li><li>Xu, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Feeder-free+growth+of+undifferentiated+human+embryonic+stem+cells.">Feeder-free growth of undifferentiated human embryonic stem cells.</a> Nat. Biotechnol. 19, 971-974 (2001).</li><li>Stein, G. S., Shi, M. J., Stencel, K., Borowski, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Thawing, Seeding, and Changing Medium of Human Embryonic Stem Cells. , (2010).</li><li>Schwartz, P. H., Brick, D. J., Nethercott, H. E., Stover, A. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Traditional+human+embryonic+stem+cell+culture.">Traditional human embryonic stem cell culture.</a> Methods Mol. Biol. 767, 107-123 .</li></ol>

No conflicts of interest declared.

The method presented in this manuscript offers a rapid and less costly alternative to eliminating fibroblast feeder cells from human embryonic cell cultures. The successful removal of fibroblasts is dependent on the existence of a tightly confluent monolayer of these cells that develops in longer stem cell cultures. After 7-10 days, the growing hESC colonies will push the feeder fibroblasts in an outward direction, generating an increasingly dense fibroblast monolayer between colonies. The strong cell-to-cell attachments...

<table border="1">
	<tbody>
		<tr>
			<td>Name of the reagent</td>
			<td>Company</td>
			<td>Catalogue number</td>
			<td>Comments (optional)</td>
		</tr>
		<tr>
			<td>DDR2</td>
			<td>Santa Cruz</td>
			<td>7555</td>
			<td>Fibroblast Marker</td>
		</tr>
		<tr>
			<td>Dapi</td>
			<td>Calbiochem</td>
			<td>268298</td>
			<td>Cell Nucleus Marker</td>
		</tr>
		<tr>
			<td>SSEA-4</td>
			<td>Millipore</td>
			<td>MAB4304</td>
			<td>Human ESC Marker</td>
		</tr>
		<tr>
			<td>Oct 3/4</td>
			<td>Santa Cruz</td>
			<td>9081</td>
			<td>Human ESC Marker</td>
		</tr>
		<tr>
			<td>Flk-1</td>
			<td>BD Pharma</td>
			<td>555307</td>
			<td>Early Differentiation Marker</td>
		</tr>
		<tr>
			<td>Tra-1-81</td>
			<td>Acris</td>
			<td>AM20377AF4-S</td>
			<td>Human ESC Marker</td>
		</tr>
	</tbody>
</table>
Table 1. Table of specific reagents used for immunostaining the hESC.

rapid fibroblast removal from high density human embryonic stem cell cultures

Mouse embryonic fibroblasts (MEFs) were used to establish human embryonic stem cells (hESCs) cultures after blastocyst isolation1. This feeder system maintains hESCs from undergoing spontaneous differentiation during cell expansion. However, this co-culture method is labor intensive, requires highly trained personnel, and yields low hESC purity4. Many laboratories have attempted to minimize the number of feeder cells in hESC cultures (i.e. incorporating matrix-coated dishes or other feeder cell types5-8). These modified culture systems have shown some promise, but have not supplanted the standard method for culturing hESCs with mitomycin C-treated mouse embyronic fibroblasts in order to retard unwanted spontaneous differentiation of the hESC cultures. Therefore, the feeder cells used in hESC expansion should be removed during differentiation experiments. Although several techniques are available for purifying the hESC colonies (FACS, MACS, or use of drug resistant vectors) from feeders, these techniques are labor intensive, costly and/or destructive to the hESC. The aim of this project was to invent a method of purification that enables the harvesting of a purer population of hESCs. We have observed that in a confluent hESC culture, the MEF population can be removed using a simple and rapid aspiration of the MEF sheet. This removal is dependent on several factors, including lateral cell-to-cell binding of MEFs that have a lower binding affinity to the styrene culture dish, and the ability of the stem cell colonies to push the fibroblasts outward during the generation of their own "niche". The hESC were then examined for SSEA-4, Oct3/4 and Tra 1-81 expression up to 10 days after MEF removal to ensure maintenance of pluripotency. Moreover, hESC colonies were able to continue growing from into larger formations after MEF removal, providing an additional level of hESC expansion.

Watch this Scientific Journal Video about Rapid Fibroblast Removal from High Density Human Embryonic Stem Cell Cultures at JoVE.com

Rapid Fibroblast Removal from High Density Human Embryonic Stem Cell Cultures

Despite ongoing efforts to transition cultures to feeder-free conditions, the derivation and culture of human embryonic stem cells (hESC) remain largely dependent on co-cultures with mouse embryonic feeders (MEFs). Here, we show a novel methodology for rapidly removing feeders from hESC cultures prior to experimentation.

Mouse embryonic fibroblasts (MEFs) were used to establish human embryonic stem cells (hESCs) cultures after blastocyst isolation1. This feeder system ...

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11.7K Views.  University of California, Merced. Despite ongoing efforts to transition cultures to feeder-free conditions, the derivation and culture of human embryonic stem cells (hESC) remain largely dependent on co-cultures with mouse embryonic feeders (MEFs). Here, we show a novel methodology for rapidly removing feeders from hESC cultures prior to experimentation.

Video: Rapid Fibroblast Removal from High Density Human Embryonic Stem Cell Cultures

Passaging HuES Human Embryonic Stem Cell-lines with Trypsin.

In this video we demonstrate how our lab routinely passages HuES human embryonic stem cell lines with trypsin.  Human embryonic stem cells are artifacts of cell culture, and tend to acquire karyotypic abnormalities with high population doublings.  Proper passaging is essential for maintaining a healthy, undifferentiated, karyotypically normal HuES human embryonic stem cell culture.  First, an expanding culture is washed in PBS to remove residual media and cell debris, then cells are overlaid with a minimal volume of warm 0.05% Trypsin-EDTA.  Trypsin is left on the cells for up to five minutes, then cells are gently dislodged with a 2mL serological pipette.  The cell suspension is collected and mixed with a large volume of HuES media, then cells are collected by gentle centrifugation.  The inactivated trypsin media mixture is removed, and cells resuspended in pre-warmed HuES media.  An appropriate split ratio is calculated (generally 1:10 to 1:20), and cells re-plated onto a 1-2 day old plate containing a monolayer of irradiated mouse embryonic fibroblast feeder cells.  The newly seeded HuES culture plate is left undisturbed for 48 hrs, then media is changed every day thereafter.  It is important not to trpsinize down to a single cell suspension, as this increases the risk of introducing karyotypic abnormalities.

In this video we demonstrate how our lab routinely passages HuES human embryonic stem cell lines with trypsin. Brought to you by JoVE.

In this video we demonstrate how our lab routinely passages HuES human embryonic stem cell lines with trypsin.  Human embryonic stem cells are artifacts ...

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 ...

Mouse Epidermal Neural Crest Stem Cell (EPI-NCSC) Cultures

EPI-NCSC are remnants of the embryonic neural crest in an adult location, the bulge of hair follicles. They are multipotent stem cells that have the physiological property to generate a wide array of differentiated cell types, including neurons, nerve supporting cells, smooth muscle cells, bone/cartilage cells and melanocytes. EPI-NCSC are easily accessible in the hairy skin and can be isolated as a highly pure population of stem cells. This video provides a detailed protocol for preparing mouse EPI-NCSC cultures from whisker follicles. The whisker pad of an adult mouse is removed, and whisker follicles dissected. The follicles are then cut longitudinally and subsequently transversely above and below the bulge region. The bulge is removed from the collagen capsule and placed in a culture plate. EPI-NCSC start to emigrate from the bulge explants 3 to 4 days later.

Mouse Epidermal Neural Crest Stem Cell EPI-NCSC Cultures

Here we show our method to isolate mouse epidermal neural crest stem cells (EPI-NCSC). Technique involves micro-dissecting whisker follicles, isolating the bulge and placeing it into tissue culture. EPI-NCSC start to emigrate from bulge explants onto the substratum within 3 - 4 days.

EPI-NCSC are remnants of the embryonic neural crest in an adult location, the bulge of hair follicles. They are multipotent stem cells that have the ...

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 ...

Preparation of Pooled Human Platelet Lysate (pHPL) as an Efficient Supplement for Animal Serum-Free Human Stem Cell Cultures

Platelet derived growth factors have been shown to stimulate cell proliferation efficiently in vivo1,2 and in vitro. This effect has been reported for mesenchymal stromal cells (MSCs), fibroblasts and endothelial colony-forming cells with platelets activated by thrombin3-5 or lysed by freeze/thaw cycles6-14 before the platelet releasate is added to the cell culture medium. The trophic effect of platelet derived growth factors has already been tested in several trials for tissue engineering and regenerative therapy.1,15-17 Varying efficiency is considered to be at least in part due to individually divergent concentrations of growth factors18,19 and a current lack of standardized protocols for platelet preparation.15,16 This protocol presents a practicable procedure to generate a pool of human platelet lysate (pHPL) derived from routinely produced platelet rich plasma (PRP) of forty to fifty single blood donations. By several freeze/thaw cycles the platelet membranes are damaged and growth factors are efficiently released into the plasma. Finally, the platelet fragments are removed by centrifugation to avoid extensive aggregate formation and deplete potential antigens. The implementation of pHPL into standard culture protocols represents a promising tool for further development of cell therapeutics propagated in an animal protein-free system.

Preparation of Pooled Human Platelet Lysate pHPL as an Efficient Supplement for Animal Serum-Free Human Stem Cell Cultures

Human platelet lysate is a rich source of growth factors and a potent supplement in cell culture. This protocol presents the process of preparing a large pool of human platelet lysate by starting from platelet rich plasma, performing several freeze-thaw cycles and depleting the platelet fragments.

Platelet derived growth factors have been shown to stimulate cell proliferation efficiently in vivo1,2 and in vitro. This effect has been reported for ...

Video Bioinformatics Analysis of Human Embryonic Stem Cell Colony Growth

Because video data are complex and are comprised of many images, mining information from video material is difficult to do without the aid of computer software.  Video bioinformatics is a powerful quantitative approach for extracting spatio-temporal data from video images using computer software to perform dating mining and analysis. In this article, we introduce a video bioinformatics method for quantifying the growth of human embryonic stem cells (hESC) by analyzing time-lapse videos collected in a Nikon BioStation CT incubator equipped with a camera for video imaging. In our experiments, hESC colonies that were attached to Matrigel were filmed for 48 hours in the BioStation CT.  To determine the rate of growth of these colonies, recipes were developed using CL-Quant software which enables users to extract various types of data from video images.  To accurately evaluate colony growth, three recipes were created. The first segmented the image into the colony and background, the second enhanced the image to define colonies throughout the video sequence accurately, and the third measured the number of pixels in the colony over time.  The three recipes were run in sequence on video data collected in a BioStation CT to analyze the rate of growth of individual hESC colonies over 48 hours. To verify the truthfulness of the CL-Quant recipes, the same data were analyzed manually using Adobe Photoshop software. When the data obtained using the CL-Quant recipes and Photoshop were compared, results were virtually identical, indicating the CL-Quant recipes were truthful. The method described here could be applied to any video data to measure growth rates of hESC or other cells that grow in colonies. In addition, other video bioinformatics recipes can be developed in the future for other cell processes such as migration, apoptosis, and cell adhesion.  

Video bioinformatics is the automated processing, analysis, understanding, and data mining of biological spatio-temporal data extracted from microscopic videos. The purpose of this article is to demonstrate a method for measuring human embryonic stem cell colony growth using a video bioinformatics method.

Because video data are complex and are comprised of many images, mining information from video material is difficult to do without the aid of computer ...

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 ...

Establishing Primary Adult Fibroblast Cultures From Rodents

The importance of using primary cells, rather than cancer cell lines, for biological studies is becoming widely recognized. Primary cells are preferred in studies of cell cycle control, apoptosis, and DNA repair, as cancer cells carry mutations in genes involved in these processes. Primary cells cannot be cultured indefinitely due to the onset of replicative senescence or aneuploidization. Hence, new cultures need to be established regularly. The procedure for isolation of rodent embryonic fibroblasts is well established, but isolating adult fibroblast cultures often presents a challenge. Adult rodent fibroblasts isolated from mouse models of human disease may be a preferred control when comparing them to fibroblasts from human patients. Furthermore, adult fibroblasts are the only available material when working with wild rodents where pregnant females cannot be easily obtained. Here we provide a protocol for isolation and culture of adult fibroblasts from rodent skin and lungs. We used this procedure successfully to isolate fibroblasts from over twenty rodent species from laboratory mice and rats to wild rodents such as beaver, porcupine, and squirrel.

This article describes a protocol for isolation and maintenance of primary fibroblast cultures from skin and lung tissue of wild rodents.

The importance of using primary cells, rather than cancer cell lines, for biological studies is becoming widely recognized.  Primary cells are preferred ...

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.