This work was supported by the Alexander von Humboldt Foundation (5090371), the Christine K&uuml;hne Center for Allergy Research and Education (CK-CARE), and the Bayerischen Staatsministerium (to K.D.).

1. SKP Isolation from Primary Fibroblast Cultures
<ol>
 <li>Fibroblast cultures either from cell banks or directly obtained from skin biopsies are maintained in culture in fibroblast growth medium DMEM containing 15% fetal calf serum, 2 mM glutamine, 10 mg/ml penicillin, and 10 mg/ml streptomycin.</li>
</ol>
Human fibroblasts GMO3349C and GMO8398A were obtained from the Coriell Institute for Medical Research (Camden, NJ) and were used in this study.
<ol start="2">
 <li>Cultures from population doublings (PPDs) 20 to 35 were used for SKP cultures at a confluency of 80%. One 10 cm tissue culture dish (BD Falcon) contains approximately 1.5x106 cells.</li>
 <li>Wash cells with PBS and incubate with 2 ml trypsin solution (0.25%, Invitrogen) for 1 hr at 37 &deg;C.</li>
 <li>Collect cells from the plate with 5 ml PBS and transfer the cell suspension to a 15 ml falcon tube.</li>
 <li>Incubate the cells at 4 &deg;C for 24 hr.</li>
 <li>Prepare SKP growth medium consisting of DMEM-F12, 3:1 (V/V) and 40 ng/ml FGF2 (BD Biosciences, 20 ng/ml EGF (BD Biosciences), B27 serum free supplement 2% (Invitrogen), 1 &mu;g/ml Fungizone (Invitrogen) and 25 &mu;m/ml Gentamycin (Invitrogen).</li>
 <li>Pellet the cells at 1,200 rpm for 5 min and resuspend the cell pellet directly in 4 ml SKP growth medium. Transfer the cell suspension to a 25 cm2 tissue culture flask (BD Falcon).</li>
 <li>Incubate the flask at 37 &deg;C and monitor the culture for sphere formation daily for 3 to 4 weeks.</li>
</ol>
2. Sphere Culture Conditions
<ol>
 <li>Culture cells in a 25 cm2 flask (BD Falcon) at 37 &deg;C, 5% CO2.</li>
 <li>Shake the flask vigorously daily to avoid cells to adhere to the bottom of the flask. If necessary, pipette up and down with a 2 ml sterile pipette to detach adherent cells and transfer the culture to a new flask.</li>
 <li>First spheres start to build within 3 to 4 days.</li>
 <li>Let spheres sediment to the bottom of the flask and change half of the medium every 3 days. To keep the same final concentration of growth factors add 2X growth factors to the freshly prepared SKP growth medium.</li>
 <li>Keep the volume constant maximum 4 ml.</li>
 <li>When spheres reach a size of ~ 200 mm they should be passaged by breaking down the spheres to smaller size by vigorous pipetting up and down with a 2 ml pipette.</li>
 <li>The culture is split into two 25 cm2 flasks (BD Falcon) and spheres cultures are feed as described in step 2.4).</li>
 <li>Spheres are collected for stem cell markers screening by day 16 to 21.</li>
</ol>
The procedure from 2.6) and 2.7) describe the propagation of the spheres to (1) allows nutriments and growth factors included in SKP medium to access all cells within each sphere and (2) to expand the SKP sphere culture prior use.
Typically Sphere cultures under our culture conditions maintain the capacity to grow over a period of three months and are passaged between 3 to 4 times.
3. Immunocytochemistry for Stem Cell Markers
<ol>
 <li>Sphere cultures are harvested in PBS by day 16 to 21. Cultures are pelleted at 1,000 rpm for 5 min.</li>
 <li>Spheres are resuspended in a small volume of PBS.</li>
 <li>Draw two circles with a DAKO pen of approximately 0.5 &mu;m in diameter on microscope slides (Fisher brand).</li>
 <li>Add 50 &mu;l of sphere suspension into the circles.</li>
 <li>Check by light microscopy for the presence of spheres in each drop.</li>
 <li>Let the drops dry under the hood.</li>
 <li>Either freeze the slides at -80 &deg;C or proceed with the immunofluoresence staining protocol.</li>
 <li>For immunofluorescence staining, fix the slides with pre-cooled Methanol (100%) at -20 &deg;C for 10 min.</li>
 <li>Wash the slides with PBS.</li>
 <li>Block the slides with PBS/10% Fetal bovine serum / 0.02% Triton X100 for at least 1 hr.</li>
 <li>Incubate with primary Antibody (e.g. anti-Nestin, anti-Oct4, anti-TG30, anti-Nanog antibodies, Table 3) diluted in blocking buffer: PBS/10% FBS for 2 hr at room temperature or overnight at 4 &deg;C.</li>
 <li>Wash 3 times with blocking buffer and incubate with secondary antibody for 1 hr at room temperature.</li>
 <li>Wash 3 times with blocking buffer and 3 times with PBS.</li>
 <li>Mount slides with Vectashield mounting medium (Vector Inc.).</li>
 <li>Analyze samples for expression of stem cell markers by immunofluorescence microscopy.</li>
</ol>
4. Realtime PCR Analysis of Expression Levels of Stem Cell Markers
<ol>
 <li>Take approximately 2-3 ml Sphere cultures from day 18 to 21.</li>
 <li>Pellet the spheres at 1,200 rpm for 5 min and aspirate all medium.</li>
 <li>Isolate RNA from the spheres using the RNeasy Minikit (Qiagen, Valencia, CA).</li>
 <li>Assess RNA purity by spectrometry and agarose gel.</li>
 <li>Synthesize cDNA (Omniscript Reverse Transcriptase (Qiagen)) using the total cellular RNA as template.</li>
 <li>Validate the stem cell markers by Realtime-PCR using primers for stem cell markers (shown in Table 1) in a Power SYBR Green PCR Mastermix (Applied Biosystems) with a concentration of 375 nM of each primer and 50 ng of template in a 20 &mu;l reaction volume. GAPDH is used as endogenous control.</li>
 <li>For the amplification use an initial denaturation at 95 &deg;C for 2.5 min followed by 40 cycles at 95 &deg;C for 5 sec and 60 &deg;C for 20 sec.</li>
 <li>Analyze the run with the 2(&Delta;&Delta;Ct) method 8.</li>
</ol>
5. Directed Differentiation into Smooth Muscle Cells
<ol>
 <li>Spheres from day 21 to 26 were plated into 6 well culture dishes (BD Falcon) in SKP medium.</li>
 <li>Cells were allowed to adhere and outgrow from the spheres in SKP medium for 72 hr.</li>
 <li>Smooth muscle cells (SMCs) differentiation started initiated by replaced the medium with SMC differentiation medium consisting of high-glucose Dulbecco's modified Eagle medium (Invitrogen) containing 5% FBS, 5 ng/ml PDGF-BB (Invitrogen), and 2.5 ng/ml TGF-b1 (Invitrogen).</li>
 <li>Medium was changed every 3 days with freshly prepared SMC differentiation medium for a period of 3 to 4 weeks in cultures.</li>
 <li>Screening for SMC markers was performed after 3 to 4 weeks by immunohistochemistry.</li>
 <li>Cells were fixed with 4% paraformaldehyde solution in PBS for 10 min.</li>
 <li>Cells were permeabilized with PBS containing 0.3% Triton X-100 for 30 min.</li>
 <li>Cells were incubated with antibodies against &alpha;SMA (MO851, Dako, 1:100), or calponin (M3556, Dako, 1:100) for 1 hr at room temperature and further processed as described in 3.12) to 3.15).</li>
</ol>

<ol>
	<li>Jahoda, C. A., Whitehouse, J., Reynolds, A. J., Hole, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hair+follicle+dermal+cells+differentiate+into+adipogenic+and+osteogenic+lineages.">Hair follicle dermal cells differentiate into adipogenic and osteogenic lineages.</a> Exp. Dermatol. 12, 849 (2003).</li><li>Watt, F. M., Celso, L. o., C, V., Silva-Vargas, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epidermal+stem+cells:+an+update.">Epidermal stem cells: an update.</a> Curr. Opin. Genet. Dev. 16, 518 (2006).</li><li>Blanpain, C., Horsley, V., Fuchs, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epithelial+stem+cells:+turning+over+new+leaves.">Epithelial stem cells: turning over new leaves.</a> Cell. 128, 445 (2007).</li><li>Hunt, D. P., Jahoda, C., Chandran, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multipotent+skin-derived+precursors:+from+biology+to+clinical+translation.">Multipotent skin-derived precursors: from biology to clinical translation.</a> Vurr. Opin. Biotechnol. 20, 522 (2009).</li><li>Toma, J. G., 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=Isolation+of+multipotent+adult+stem+cells+from+the+dermis+of+mammalian+skin.">Isolation of multipotent adult stem cells from the dermis of mammalian skin.</a> Nat. Cell Biol. 3, 778 (2001).</li><li>Fernandes, K. J. 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=A+dermal+niche+for+multipotent+adult+skin-derived+precursor+cells.">A dermal niche for multipotent adult skin-derived precursor cells.</a> Nat. Cell Biol. 6, 1082 (2004).</li><li>Wenzel, V., 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=Na&#239;ve+adult+stem+cells+from+patients+with+Hutchinson-Gilford+progeria+syndrome+express+low+levels+of+progerin+in+vivo.">Na&#239;ve adult stem cells from patients with Hutchinson-Gilford progeria syndrome express low levels of progerin in vivo.</a> Bio. Open. 1, (2012).</li><li>Livak, K. J., Schmittgen, T. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+relative+gene+expression+data+using+real-time+quantitative+PCR+and+the+2(-Delta+Delta+C(T))+Method.">Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C(T)) Method.</a> Methods. 25, 402 (2001).</li><li>Biernaskie, J. A., McKenzie, I. A., Toma, J. T., Miller, F. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+skin-derived+precursors+(SKPs)+and+differentiation+and+enrichment+of+their+Schwann+cell+progeny.">Isolation of skin-derived precursors (SKPs) and differentiation and enrichment of their Schwann cell progeny.</a> Nature Protocol. 1, 2803 (2006).</li><li>Toma, J. G., McKenzie, I., Bagli, D., Miller, F. D. <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+characterization+of+multipotent+skin-derived+precursors+from+human+skin.">Isolation and characterization of multipotent skin-derived precursors from human skin.</a> Stem Cells. 23, 727 (2005).</li><li>Fernandes, K. 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=Analysis+of+the+neurogenic+potential+of+multipotent+skin-derived+precursors.">Analysis of the neurogenic potential of multipotent skin-derived precursors.</a> Electrophoresis. 201, 32 (2006).</li><li>Hill, l. K. 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=Human+embryonic+stem+cell-derived+vascular+progenitor+cells+capable+of+endothelial+and+smooth+muscle+cell+function.">Human embryonic stem cell-derived vascular progenitor cells capable of endothelial and smooth muscle cell function.</a> Exp. Hematol. 38, 246 (2010).</li></ol>

We have nothing to disclose.

Using the method described herein, na&iuml;ve dermal stem cells can be isolated from primary dermal fibroblast cultures. Using this approach, we recently reported the isolation and characterization of adult stem cells from fibroblast cultures derived from patients with a rare genetic syndrome, Hutchinson-Gilford progeria syndrome 7. As show herein those precursor cells express stem cell markers are capable of self-renewal and can be directed to differentiate into different cellular lineages including fib...

<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>DMEM high glucose</td>
			<td>Invitrogen</td>
			<td>31966-047</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>DMEM low glucose</td>
			<td>Invitrogen</td>
			<td>21885-108</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>fetal bovine serum</td>
			<td>Invitrogen</td>
			<td>10270-106</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>L-glutamine</td>
			<td>Invitrogen</td>
			<td>25030-024</td>
			<td>Final conc.: 200 mM</td>
		</tr>
		<tr>
			<td>Penicillin/ Streptomycin</td>
			<td>Invitrogen</td>
			<td>15140-122</td>
			<td>Final conc.: 10 mg/ml /10 mg /ml</td>
		</tr>
		<tr>
			<td>trypsin solution (0.25%)</td>
			<td>Invitrogen</td>
			<td>25200-056</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>F-12 Nutrient Mixture (Ham)</td>
			<td>Invitrogen</td>
			<td>21765-029</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>FGF2</td>
			<td>BD Biosciences</td>
			<td>4114-TC-01M</td>
			<td>Final conc.: 40 ng/ml</td>
		</tr>
		<tr>
			<td>EGF</td>
			<td>BD Biosciences</td>
			<td>236-EG-200</td>
			<td>Final conc.: 20 ng/ml</td>
		</tr>
		<tr>
			<td>PDGFBB</td>
			<td>Invitrogen</td>
			<td>PHG0043</td>
			<td>Final conc.: 5 ng/ml</td>
		</tr>
		<tr>
			<td>TGF-b1</td>
			<td>Invitrogen</td>
			<td>PHG9204</td>
			<td>Final conc.: 2.5 ng/ml</td>
		</tr>
		<tr>
			<td>25 cm2 flask</td>
			<td>Omnilab</td>
			<td>FALC353109</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>PBS w/o CaMg</td>
			<td>Invitrogen</td>
			<td>14190-169</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>B27</td>
			<td>Invitrogen</td>
			<td>17504-044</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Roth</td>
			<td>8388.2</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Vectashield mounting medium</td>
			<td>Vector Inc.</td>
			<td>H-1200</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>RNeasy Minikit</td>
			<td>Qiagen, Valencia, CA</td>
			<td>74104</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Omniscript Reverse Transcriptase</td>
			<td>Qiagen</td>
			<td>205113</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>SsoFast EvaGreen Supermix</td>
			<td>BioRad</td>
			<td>172-5201</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Fungizone</td>
			<td>Invitrogen</td>
			<td>15290-018</td>
			<td>Final conc.:1 mg/ml</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>Table 2. Specific reagents and equipment.</td>
		</tr>
	</tbody>
</table>

na&iuml;ve adult stem cells isolation from primary human fibroblast cultures

Over the last decade, several adult stem cell populations have been identified in human skin 1-4. The isolation of multipotent adult dermal precursors was first reported by Miller F. D laboratory 5, 6. These early studies described a multipotent precursor cell population from adult mammalian dermis 5. These cells--termed SKPs, for skin-derived precursors-- were isolated and expanded from rodent and human skin and differentiated into both neural and mesodermal progeny, including cell types never found in skin, such as neurons 5. Immunocytochemical studies on cultured SKPs revealed that cells expressed vimentin and nestin, an intermediate filament protein expressed in neural and skeletal muscle precursors, in addition to fibronectin and multipotent stem cell markers 6. Until now, the adult stem cells population SKPs have been isolated from freshly collected mammalian skin biopsies.
Recently, we have established and reported that a population of skin derived precursor cells could remain present in primary fibroblast cultures established from skin biopsies 7. The assumption that a few somatic stem cells might reside in primary fibroblast cultures at early population doublings was based upon the following observations: (1) SKPs and primary fibroblast cultures are derived from the dermis, and therefore a small number of SKP cells could remain present in primary dermal fibroblast cultures and (2) primary fibroblast cultures grown from frozen aliquots that have been subjected to unfavorable temperature during storage or transfer contained a small number of cells that remained viable 7. These rare cells were able to expand and could be passaged several times. This observation suggested that a small number of cells with high proliferation potency and resistance to stress were present in human fibroblast cultures 7.
We took advantage of these findings to establish a protocol for rapid isolation of adult stem cells from primary fibroblast cultures that are readily available from tissue banks around the world (Figure 1). This method has important significance as it allows the isolation of precursor cells when skin samples are not accessible while fibroblast cultures may be available from tissue banks, thus, opening new opportunities to dissect the molecular mechanisms underlying rare genetic diseases as well as modeling diseases in a dish.

We show that a population of cells that selectively expand to generate SKP spheres under controlled growth condition consisting of EGF and FGF2 are present in primary dermal fibroblast cultures (Figure 1) as we reported recently 7.
Fibroblast cultures from PPDs 15 to 25 that typically correspond to the primary fibroblasts strains available from cell banks were used in this study. Fibroblast cultures submitted to the double treatment consisting of cold tempera...

Watch this Scientific Journal Video about NaÃ¯ve Adult Stem Cells Isolation from Primary Human Fibroblast Cultures at JoVE.com

Na&amp;#239;ve Adult Stem Cells Isolation from Primary Human Fibroblast Cultures

We report a method to isolate na&#239;ve multipotent skin-derived precursor (SKP) cells from primary human fibroblast cultures. We show that these SKPs derived from fibroblast cultures share similar stem cell properties to the ones derived directly from human skin biopsies. These cells express the neural crest marker, nestin, in addition to the multipotent markers such as OCT4 and Nanog.

Na&iuml;ve Adult Stem Cells Isolation from Primary Human Fibroblast Cultures

Over the last decade, several adult stem cell  populations have been identified in human skin 1-4.  The isolation of multipotent adult dermal precursors ...

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14.1K Views.  Technische Universität München. Мы сообщаем о способе выделения наивным мультипотентны, полученных из кожи предшественника (SKP) клеток из первичной культуры фибробластов человека. Покажем, что эти SKPs, полученных из культур фибробластов имеют сходные свойства стволовых клеток, чтобы те, выво...

Video: Na&#239;ve Adult Stem Cells Isolation from Primary Human Fibroblast Cultures

Isolation and Large Scale Expansion of Adult Human Endothelial Colony Forming Progenitor Cells

This paper introduces a novel recovery strategy for endothelial colony forming progenitor cells (ECFCs) from heparinized but otherwise unmanipulated adult human peripheral blood within a mean of 12 days. After large scale expansion &gt;1x108 ECFCs can be obtained for further tests. Advantageously by using pHPL the contact of human cells with bovine serum antigens can be excluded. By flow cytometry and immunohistochemistry the isolated cells can be characterized as ECFC and their in vitro functionality to form vascular like structures can be tested in a matrigel assay. Further these cells can be subcutaneously injected in a mouse model to form functional, perfused vessels in vivo. After long term expansion and cryopreservation proliferation, function and genomic stability appear to be preserved. 3,4
This animal-protein free isolation and expansion method is easily applicable to generate a large quantity of ECFCs.

Endothelial colony forming progenitor cells (ECFCs) are a promising tool to study vascular homeostasis and repair.1,2 This paper introduces a novel animal-serum free method for isolation and expansion of ECFC from heparinised adult human peripheral blood with pooled human platelet lysate (pHPL) diminishing the risk of anti-bovine immunisation.

This paper introduces a novel recovery strategy for endothelial colony forming progenitor cells (ECFCs) from heparinized but otherwise unmanipulated adult ...

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 ...

Isolation of Stem Cells from Human Pancreatic Cancer Xenografts

Cancer stem cells (CSCs) have been identified in a growing number of malignancies and are functionally defined by their ability to undergo self-renewal and produce differentiated progeny1. These properties allow CSCs to recapitulate the original tumor when injected into immunocompromised mice. CSCs within an epithelial malignancy were first described in breast cancer and found to display specific cell surface antigen expression (CD44+CD24low/-)2. Since then, CSCs have been identified in an increasing number of other human malignancies using CD44 and CD24 as well as a number of other surface antigens. Physiologic properties, including aldehyde dehydrogenase (ALDH) activity, have also been used to isolate CSCs from malignant tissues3-5.
Recently, we and others identified CSCs from pancreatic adenocarcinoma based on
ALDH activity and the expression of the cell surface antigens CD44 and CD24, and CD1336-8. These highly tumorigenic populations may or may not be overlapping and display other functions. We found that ALDH+ and CD44+CD24+ pancreatic CSCs are similarly tumorigenic, but ALDH+ cells are relatively more invasive8. In this protocol we describe a method to isolate viable pancreatic CSCs from low-passage human
xenografts9. Xenografted tumors are harvested from mice and made into a single-cell suspension. Tissue debris and dead cells are separated from live cells and then stained using antibodies against CD44 and CD24 and using the ALDEFLUOR reagent,
a fluorescent substrate of ALDH10. CSCs are then isolated by fluorescence activated cell sorting. Isolated CSCs can then be used for analytical or functional assays requiring viable cells.

Cancer stem cells (CSCs) have been identified in a number of malignancies. In this protocol we describe a flow cytometric method utilizing aldehyde dehydrogenase activity and CD44 and CD24 expression to isolate CSCs from human pancreatic adenocarcinoma xenografts. These viable cells can then be used in functional and analytical studies.

Cancer stem cells (CSCs) have been identified in a growing number of malignancies and are functionally defined by their ability to undergo self-renewal ...

Isolation and Culture of Adult Epithelial Stem Cells from Human Skin

The homeostasis of all self-renewing tissues is dependent on adult stem cells. As undifferentiated stem cells undergo asymmetric divisions, they generate daughter cells that retain the stem cell phenotype and transit-amplifying cells (TA cells) that migrate from the stem cell niche, undergo rapid proliferation and terminally differentiate to repopulate the tissue.
Epithelial stem cells have been identified in the epidermis, hair follicle, and intestine as cells with a high in vitro proliferative potential and as slow-cycling label-retaining cells in vivo 1-3. Adult, tissue-specific stem cells are responsible for the regeneration of the tissues in which they reside during normal physiologic turnover as well as during times of stress 4-5. Moreover, stem cells are generally considered to be multi-potent, possessing the capacity to give rise to multiple cell types within the tissue 6. For example, rodent hair follicle stem cells can generate epidermis, sebaceous glands, and hair follicles 7-9. We have shown that stem cells from the human hair follicle bulge region exhibit multi-potentiality 10.
Stem cells have become a valuable tool in biomedical research, due to their utility as an in vitro system for studying developmental biology, differentiation, tumorigenesis and for their possible therapeutic utility. It is likely that adult epithelial stem cells will be useful in the treatment of diseases such as ectodermal dysplasias, monilethrix, Netherton syndrome, Menkes disease, hereditary epidermolysis bullosa and alopecias 11-13. Additionally, other skin problems such as burn wounds, chronic wounds and ulcers will benefit from stem cell related therapies 14,15. Given the potential for reprogramming of adult cells into a pluripotent state (iPS cells)16,17, the readily accessible and expandable adult stem cells in human skin may provide a valuable source of cells for induction and downstream therapy for a wide range of disease including diabetes and Parkinson's disease.

A rapid, robust way of isolating viable adult epithelial stem cells from human skin is described. The method utilizes enzymatic digestion of skin collagen matrix , followed by plucking of hair follicles and isolation of single cell suspensions or tissue fragments for cell culture.

The homeostasis of all self-renewing tissues is dependent on adult stem cells. As undifferentiated stem cells undergo asymmetric divisions, they generate ...

Selecting and Isolating Colonies of Human Induced Pluripotent Stem Cells Reprogrammed from Adult Fibroblasts

Herein we present a protocol of reprogramming human adult fibroblasts into human induced pluripotent stem cells (hiPSC) using retroviral vectors encoding Oct3/4, Sox2, Klf4 and c-myc (OSKM) in the presence of sodium butyrate 1-3. We used this method to reprogram late passage (&gt;p10) human adult fibroblasts derived from Friedreich's ataxia patient (GM03665, Coriell Repository). The reprogramming approach includes highly efficient transduction protocol using repetitive centrifugation of fibroblasts in the presence of virus-containing media. The reprogrammed hiPSC colonies were identified using live immunostaining for Tra-1-81, a surface marker of pluripotent cells, separated from non-reprogrammed fibroblasts and manually passaged 4,5. These hiPSC were then transferred to Matrigel plates and grown in feeder-free conditions, directly from the reprogramming plate. Starting from the first passage, hiPSC colonies demonstrate characteristic hES-like morphology. Using this protocol more than 70% of selected colonies can be successfully expanded and established into cell lines. The established hiPSC lines displayed characteristic pluripotency markers including surface markers TRA-1-60 and SSEA-4, as well as nuclear markers Oct3/4, Sox2 and Nanog. 
The protocol presented here has been established and tested using adult fibroblasts obtained from Friedreich's ataxia patients and control individuals 6, human newborn fibroblasts, as well as human keratinocytes.

We present a protocol for efficient reprogramming of human somatic cells into human induced pluripotent stem cells (hiPSC) using retroviral vectors encoding Oct3/4, Sox2, Klf4 and c-myc (OSKM) and identification of correctly reprogrammed hiPSC by live staining with Tra-1-81 antibody.

Herein we present a protocol of reprogramming human adult fibroblasts into human induced pluripotent stem cells (hiPSC) using retroviral vectors encoding ...

Preparation of Mouse Embryonic Fibroblast Cells Suitable for Culturing Human Embryonic and Induced Pluripotent Stem Cells

In general, human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs)1 can be cultured under variable conditions. However, it is not easy to establish an effective system for culturing these cells. Since the culture conditions can influence gene expression that confers pluripotency in hESCs and hiPSCs, the optimization and standardization of the culture method is crucial.
The establishment of hESC lines was first described by using MEFs as feeder cells and fetal bovine serum (FBS)-containing culture medium2. Next, FBS was replaced with knockout serum replacement (KSR) and FGF2, which enhances proliferation of hESCs3. Finally, feeder-free culture systems enable culturing cells on Matrigel-coated plates in KSR-containing conditioned medium (medium conditioned by MEFs)4. Subsequently, hESCs culture conditions have moved towards feeder-free culture in chemically defined conditions5-7. Moreover, to avoid the potential contamination by pathogens and animal proteins culture methods using xeno-free components have been established8.
To obtain improved conditions mouse feeder cells have been replaced with human cell lines (e.g. fetal muscle and skin cells9, adult skin cells10, foreskin fibroblasts11-12, amniotic mesenchymal cells13). However, the efficiency of maintaining undifferentiated hESCs using human foreskin fibroblast-derived feeder layers is not as high as that from mouse feeder cells due to the lower level of secretion of Activin A14. Obviously, there is an evident difference in growth factor production by mouse and human feeder cells.
Analyses of the transcriptomes of mouse and human feeder cells revealed significant differences between supportive and non-supportive cells. Exogenous FGF2 is crucial for maintaining self-renewal of hESCs and hiPSCs, and has been identified as a key factor regulating the expression of Tgf&beta;1, Activin A and Gremlin (a BMP antagonist) in feeder cells. Activin A has been shown to induce the expression of OCT4, SOX2, and NANOG in hESCs15-16.
For long-term culture, hESCs and hiPSCs can be grown on mitotically inactivated MEFs or under feeder-free conditions in MEF-CM (MEF-Conditioned Medium) on Matrigel-coated plates to maintain their undifferentiated state. Success of both culture conditions fully depends on the quality of the feeder cells, since they directly affect the growth of hESCs.
Here, we present an optimized method for the isolation and culture of mouse embryonic fibroblasts (MEFs), preparation of conditioned medium (CM) and enzyme-linked immunosorbent assay (ELISA) to assess the levels of Activin A within the media.

The quality of mouse embryonic fibroblasts (MEFs) is dictated by the right strain of mouse such as CF-1. Pluripotency-supportive MEFs and conditioned media (CM) obtained from these should contain optimal concentrations of Activin A, Gremlin and Tgf&beta;1 needed for the Activin/Nodal and FGF pathways to co-operatively maintain self-renewal and pluripotency.

In general, human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs)1 can be cultured under variable conditions. However, it ...

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.

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 ...

Isolation of Immune Cells from Primary Tumors

Tumors create a unique immunosuppressive microenvironment (tumor microenvironment, TME) whereby leukocytes are recruited into the tumor by various chemokines and growth factors 1,2. However, once in the TME, these cells lose the ability to promote anti-tumor immunity and begin to support tumor growth and down-regulate anti-tumor immune responses 3-4. Studies on tumor-associated leukocytes have mainly focused on cells isolated from tumor-draining lymph nodes or spleen due to the inherent difficulties in obtaining sufficient cell numbers and purity from the primary tumor. While identifying the mechanisms of cell activation and trafficking through the lymphatic system of tumor bearing mice is important and may give insight to the kinetics of immune responses to cancer, in our experience, many leukocytes, including dendritic cells (DCs), in tumor-draining lymph nodes have a different phenotype than those that infiltrate tumors 5,6 . Furthermore, we have previously demonstrated that adoptively-transferred T cells isolated from the tumor-draining lymph nodes are not tolerized and are capable of responding to secondary stimulation in vitro unlike T cells isolated from the TME, which are tolerized and incapable of proliferation or cytokine production 7,8. Interestingly, we have shown that changing the tumor microenvironment, such as providing CD4+ T helper cells via adoptive transfer, promotes CD8+ T cells to maintain pro-inflammatory effector functions 5. The results from each of the previously mentioned studies demonstrate the importance of measuring cellular responses from TME-infiltrating immune cells as opposed to cells that remain in the periphery. To study the function of immune cells which infiltrate tumors using the Miltenyi Biotech isolation system9, we have modified and optimized this antibody-based isolation procedure to obtain highly enriched populations of antigen presenting cells and tumor antigen-specific cytotoxic T lymphocytes. The protocol includes a detailed dissection of murine prostate tissue from a spontaneous prostate tumor model (TRansgenic Adenocarcinoma of the Mouse Prostate -TRAMP) 10 and a subcutaneous melanoma (B16) tumor model followed by subsequent purification of various leukocyte populations.

In this report, we describe a protocol for isolating highly purified populations of leukocytes that infiltrate tumors. This protocol is adapted from the Miltenyi Biotech protocol to enhance yield and purity for isolating cells from complex tumor tissue.

Tumors create a unique immunosuppressive microenvironment (tumor microenvironment, TME) whereby leukocytes are recruited into the tumor by various ...

Isolation and Culture of Individual Myofibers and their Satellite Cells from Adult Skeletal Muscle

Muscle regeneration in the adult is performed by resident stem cells called satellite cells. Satellite cells are defined by their position between the basal lamina and the sarcolemma of each myofiber. Current knowledge of their behavior heavily relies on the use of the single myofiber isolation protocol. In 1985, Bischoff described a protocol to isolate single live fibers from the Flexor Digitorum Brevis (FDB) of adult rats with the goal to create an in vitro system in which the physical association between the myofiber and its stem cells is preserved 1. In 1995, Rosenblattmodified the Bischoff protocol such that myofibers are singly picked and handled separately after collagenase digestion instead of being isolated by gravity sedimentation 2, 3. The Rosenblatt or Bischoff protocol has since been adapted to different muscles, age or conditions 3-6. The single myofiber isolation technique is an indispensable tool due its unique advantages. First, in the single myofiber protocol, satellite cells are maintained beneath the basal lamina. This is a unique feature of the protocol as other techniques such as Fluorescence Activated Cell Sorting require chemical and mechanical tissue dissociation 7. Although the myofiber culture system cannot substitute for in vivo studies, it does offer an excellent platform to address relevant biological properties of muscle stem cells. Single myofibers can be cultured in standard plating conditions or in floating conditions. Satellite cells on floating myofibers are subjected to virtually no other influence than the myofiber environment. Substrate stiffness and coating have been shown to influence satellite cells' ability to regenerate muscles 8, 9 so being able to control each of these factors independently allows discrimination between niche-dependent and -independent responses. Different concentrations of serum have also been shown to have an effect on the transition from quiescence to activation. To preserve the quiescence state of its associated satellite cells, fibers should be kept in low serum medium 1-3. This is particularly useful when studying genes involved in the quiescence state. In serum rich medium, satellite cells quickly activate, proliferate, migrate and differentiate, thus mimicking the in vivo regenerative process 1-3. The system can be used to perform a variety of assays such as the testing of chemical inhibitors; ectopic expression of genes by virus delivery; oligonucleotide based gene knock-down or live imaging. This video article describes the protocol currently used in our laboratory to isolate single myofibers from the Extensor Digitorum Longus (EDL) muscle of adult mice (6-8 weeks old).

Isolation and culture of myofibers is the gold standard in vitro system to study the transition of satellite cells through quiescence, activation and differentiation. Importantly, the single myofiber culture system preserves the myofiber/stem cell association, which is an essential component of the muscle stem cell niche.

Muscle  regeneration in the adult is performed by resident stem cells called satellite  cells. Satellite cells are defined by  their position between the ...

Manual Isolation of Adipose-derived Stem Cells from Human Lipoaspirates

In 2001, researchers at the University of California, Los Angeles, described the isolation of a new population of adult stem cells from liposuctioned adipose tissue that they initially termed Processed Lipoaspirate Cells or PLA cells. Since then, these stem cells have been renamed as Adipose-derived Stem Cells or ASCs and have gone on to become one of the most popular adult stem cells populations in the fields of stem cell research and regenerative medicine. Thousands of articles now describe the use of ASCs in a variety of regenerative animal models, including bone regeneration, peripheral nerve repair and cardiovascular engineering. Recent articles have begun to describe the myriad of uses for ASCs in the clinic. The protocol shown in this article outlines the basic procedure for manually and enzymatically isolating ASCs from large amounts of lipoaspirates obtained from cosmetic procedures. This protocol can easily be scaled up or down to accommodate the volume of lipoaspirate and can be adapted to isolate ASCs from fat tissue obtained through abdominoplasties and other similar procedures.

In 2001, researchers at UCLA described the isolation of a population of adult stem cells, termed Adipose-derived Stem Cells or ASCs, from adipose tissue. This article outlines the isolation of ASCs from lipoaspirates using a manual, enzymatic digestion protocol using collagenase.

In 2001, researchers at the University of  California, Los Angeles, described the isolation of a new population of adult  stem cells from liposuctioned ...