The authors are greatly appreciative of Ms. Haiying Pan and Mr. Ian Bellayr for their technical help on cell isolation for the current films and Mr. Kyle Holden and Mr. Jonathan Lucas for their help on slide editing. Many thanks to the following list of persons who have been involved with the development of the modified preplate techniques over the past years: Drs. Burhan Gharaibeh, BaoHong Cao, Deasy Bridget, Thomas R. Payne, Aiping Lu, Hairong Peng, Hideki Oshima, Bo Zeng, Xiaodong Mu, Kimimasa Tobita, Ron Jankowski, Makato Ikezawa. We are grateful for the technical assistance from James H. Cummins, Ryan Pruchnic, Joseph Feduska, Rebecca C. Schugar, Haiying Pan and Jessica Tebbets. The author also would like to acknowledge the financial support for this work from the Muscular Dystrophy Association (MDA), the National Institutes of Health (NIH), the Department of Defense (DOD), the Children's Hospital of Pittsburgh of UPMC, the Department of Orthopaedic Surgery, and the University of Pittsburgh.

In general, the complete modified preplate procedure requires 1-2 days of preparation, 1 week of performing the technical procedure, 2-3 days of cell identification with immunocytochemistry, and an additional 2-3 weeks of stem cell population expansion. The equipment required for stem cell culture are similar to that of other cell culture systems which includes a bench-top centrifuge, CO2 incubator, Laminar flow tissue culture hood and an inverted microscope equipped with fluorescence and a digital camera. The isolated stem cells also can be cloned and can be stored long-term in liquid nitrogen for the current or future studies 1,2. All reagents and materials used for this procedure must be sterile and handled aseptically. Step 1: Preparation <ol> <li>Collagen coat tissue culture dishes and flasks: Type I collagen derived from calf skin (0.1 g in 1 liter; Sigma-Aldrich). The plasticware to coat includes: T-25 flasks, 6 or 12 well plates, dishes (60 and 100 mm, BD Falcon) as described before 1,2. Gently shake the plasticware every half hour, for 4 hours to ensure even coating of the collagen. The collagen solution is then removed. And the coated plasticware is then allowed to dry in the tissue culture hood with the UV light and the hood both on, to ensure sterility, and finally recapped or covered for later use.</li> <li>Prepare cell culture medium : 400mL DMEM (DMEM, high glucose; Invitrogen), 50mL Heat Inactivated Fetal Bovine Serum (FBS, Invitrogen), 50mL Horse Serum (HS, Invitrogen), and 5 mL Chick Embryo Extract (CEE; Accurate Chemical Co.) will be vacuum filtered using a disposable 0.22-&mu;m 500-ml sterile filter system (Corning). Sterile penicillin/streptomycin solution (Invitrogen) will be added finally 100 Units/mL. The prepared solutions can be stored at 4&deg;C for at least one month. This solution is used to detach the cells from the flask when splitting cultures or preparing the cells for transplantation.</li> <li>Warm up solutions for cell isolation: The following reagents need to be warmed up to 37&deg;C prior to their use for cell isolation: Hank's Buffered Salt Solution (HBSS, Invitrogen); 0.2% (wt/vol) collagenase-type XI (Sigma-Aldrich), with an average of 3,200 collagen digestion units per mL HBSS; Dispase 2.4 units/1mL (Invitrogen); 0.5% (wt/vol) trypsin (Invitrogen).</li> <li>Sterilize surgical equipment in preparation: Surgical procedure require sterile surgical instruments including: different-sized forceps, micro-scissors, iris scissors and/or scalpel blades. Additionally, 15 and 50-mL polypropylene centrifuge tubes (BD Falcon); Cell strainer (pore size 70 m) (BD Falcon); 18-, 23- and 27-gauge needles (BD PrecisionGlide); and 10- or 20-ml sterile syringes (BD).</li> </ol> Step 2: Tissue biopsies, isolation and mechanical dissociation1-4 The tissue biopsies are performed under a sterile culture hood and include freshly harvested tendons and skeletal muscles are obtained from the tibia or soleus muscles of the hindlimb of wild-type mice (Female C57BL/6J, 4-5 weeks of age or younger, Jackson Laboratory). Any visible connective tissue, blood vessels, and adipose tissue are then removed from the biopsy samples. The tissues of tendon and muscle are then carefully identified under a surgical dissecting microscope to remove remnants of skin and bone and placed in a dish containing cold (4&deg;C) HBSS (supplemented with add 5 % of FBS). The isolated tissues are then separately placed on collagen coated dishes containing cold HBSS and will be minced (&lt;1x1 mm3) into a coarse slurry using micro-scissors and/or scalpel blades. Step 3: Enzymatic digestion of the tissues: The minced tissue is then enzymatically dissociated through a series of steps2,4,5 <ol> <li>Transfer the minced tissue slurries into separate 15-ml tubes and centrifuge at ~3500 rpm at 4 &deg;C for 5 mins.</li> <li>Remove the supernatant, wash with HBSS and repeat the centrifugation again.</li> <li>Remove the supernatant, and digest these slurries by adding 10 ml of prewarmed 0.2% collagenase-type XI (Sigma). Incubate for 60 mins at 37 &deg;C while continuously gently rocking the tubes. Alternatively, shake by hand every 10 min.</li> <li>Centrifuge and resuspend these slurries in 10 ml dispase (2.4 Units/mL, Gibco) solution. Incubate for 45 mins at 37 &deg;C, shaking with hands or gently rocking every 10 min.</li> <li>Centrifuge and re-suspend these slurries in 10 ml of 0.2% trypsin HBSS solution. Incubation will vary based on the extent to which the single cells are released from the tissues which can be performed by observing the suspension under microscope. It is not recommend to exceed 30 mins at 37 &deg;C with inverting the tubes or gently rocking every 10 min.</li> <li>Centrifuge the resulting cells and re-suspend the cell pellet in 10 ml of Proliferation Medium (PM).</li> <li>Dissociate the cell suspension by passing the extract through a series of needles. The cells are then passed 2 times through an 18G, then a 23G, and finally a 27G needle.</li> <li>Pass the cell extract through a 70-&mu;m cell strainer.</li> </ol> Step 4: Preplating to isolate different cell populations based on cell adhesion rate1-3 <ol> <li>Centrifuge and resuspend the cell pellets in Proliferation Medium.</li> <li>Plate the cell mixtures onto a collagen-coated T-25 flask (or 60 mm dish) and mark it as PP1. The cell suspension should be observed as possessing large numbers of refractive nuclei and other debris under the microscope.</li> <li>Incubate at 37 &deg;C in a humidified, 5% CO2 incubator for 2 hours.</li> <li>Transfer nonadherent cells to a new collagen-coated T-25 flask (or 60 mm dish) and mark is as PP2. Add 5 ml of PM into the plate labeled PP1. The early adhering cells which attach to the flask are mostly myofibroblasts3.</li> <li>Return the flasks to the incubator for another 24 hours, transfer nonadherent cells to a new collagen-coated T-25 flask (or dish) and mark it as PP3. Add 5 ml of Proliferation Medium into the plate labeled PP2. These adhering cells which attach to this flask are mostly fibroblasts2,3.</li> <li>Return flasks to the incubator and repeat the procedure in another 24 hours until population PP6 is created. Maintain each group of suspended cells and allow them to proliferate and examining them regularly using an inverted microscope. PP3-PP4 are mostly myoblasts while muscle satellite cells are often seen mostly in PP5 2.</li> <li>Most of the slowly adhering cells typically attach by PP6. At this stage, the cells appear small, round, light refractive and are very sparse in number and are considered to be a stem cell population 1,2.</li> </ol> Step 5: Identification and expansion of isolated stem cells <ol> <li>The isolated PP6 cells are very few in number and need to be maintained in FBS rich Proliferation Medium (20% FBS in DMEM) that is changed daily. Most of the cells present in the PP6 culture die during the following 1-2 weeks of culturing, but a large, healthy PP6 population is usually created after an additional 1-2 weeks of expansion. The stem cells isolated from mice highly express stem cell antigen 1 (Sca1), CD34, fetal liver kinase 1 (Flk1), and other stem markers1,2,6,7 which can be visualized via immunocytochemical staining. These stem cells also exhibit multiple differentiation capacities3,6,8.</li> <li>The isolated cells are maintained and expanded at a low cell density in culture (12-well dishes at 50-100 cells/well or &lt;20-30% confluence in the flask or dish) to avoid differentiation 1,2. Very few cells form clones during expansion, and these cloned stem cells can undergo long time proliferation (LTP) for any other competence studies. The cloned stem cells also can be store in liquid nitrogen using general cell storage procedures e.g. PM medium with 10% DMSO. Make a number of low passage stocks of the stem cells for any other back up studies.</li> </ol>

<ol>
	<li>Gharaibeh, B. <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+a+slowly+adhering+cell+fraction+containing+stem+cells+from+murine+skeletal+muscle+by+the+preplate+technique.">Isolation of a slowly adhering cell fraction containing stem cells from murine skeletal muscle by the preplate technique.</a> Nat Protoc. 3, 1501-1509 (2008).</li><li>Qu-Petersen, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+a+novel+population+of+muscle+stem+cells+in+mice:+potential+for+muscle+regeneration.">Identification of a novel population of muscle stem cells in mice: potential for muscle regeneration.</a> J Cell Biol. 157, 851-864 (2002).</li><li>Li, Y. &. a. m. p. ;. a. m. p., Huard, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differentiation+of+muscle-derived+cells+into+myofibroblasts+in+injured+skeletal+muscle.">Differentiation of muscle-derived cells into myofibroblasts in injured skeletal muscle.</a> Am J Pathol. 161, 895-907 (2002).</li><li>Watt, D. J., Lambert, K., Morgan, J. E., Partridge, T. A. &. a. m. p. ;. a. m. p., Sloper, 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=Incorporation+of+donor+muscle+precursor+cells+into+an+area+of+muscle+regeneration+in+the+host+mouse.">Incorporation of donor muscle precursor cells into an area of muscle regeneration in the host mouse.</a> J Neurol Sci. 57, 319-331 (1982).</li><li>Lu, A. <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+myogenic+progenitor+populations+from+Pax7-deficient+skeletal+muscle+based+on+adhesion+characteristics.">Isolation of myogenic progenitor populations from Pax7-deficient skeletal muscle based on adhesion characteristics.</a> Gene Ther. 15, 1116-1125 (2008).</li><li>Lee, J. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clonal+isolation+of+muscle-derived+cells+capable+of+enhancing+muscle+regeneration+and+bone+healing.">Clonal isolation of muscle-derived cells capable of enhancing muscle regeneration and bone healing.</a> J Cell Biol. 150, 1085-1100 (2000).</li><li>Cao, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+receptors+in+the+maturation-dependent+adenoviral+transduction+of+myofibers.">The role of receptors in the maturation-dependent adenoviral transduction of myofibers.</a> Gene Ther. 8, 627-637 (2001).</li><li>Cao, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Muscle+stem+cells+differentiate+into+haematopoietic+lineages+but+retain+myogenic+potential.">Muscle stem cells differentiate into haematopoietic lineages but retain myogenic potential.</a> Nat Cell Biol. 5, 640-646 (2003).</li><li>Huard, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regenerative+medicine+based+on+muscle+stem+cells.">Regenerative medicine based on muscle stem cells.</a> J Musculoskelet Neuronal Interact. 8, (2008).</li><li>Gates, C. B., Karthikeyan, T., Fu, F. &. a. m. p. ;. a. m. p., Huard, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regenerative+medicine+for+the+musculoskeletal+system+based+on+muscle-derived+stem+cells.">Regenerative medicine for the musculoskeletal system based on muscle-derived stem cells.</a> J Am Acad Orthop Surg. 16, 68-76 (2008).</li></ol>

No conflicts of interest declared.

It has been recognized that some adult tissues contain multiple stem cells. Over the past few years of study, stem cells have been detected in the soft musculoskeletal tissues, including skeletal muscle and tendon. This current protocol details a procedure, known as the modified preplate technique, that has been successfully used in our laboratory to isolate adult stem cells from tendons and skeletal muscle. Using the modified preplate technique described above the cells can be divided into several populations based on their adhesion characteristics to collagen coated flasks (Figure 1). Fibroblasts and myofibroblasts found within the tissues quickly adhere to the collagen coated flasks within 24-48 hours and are initially separated from other cells in PP1-PP2. The myogenic or endothelial cells adhere to collagen coated flasks after a longer time period, within 48-96 hours (PP3-PP5), and can be harvested and identified by their cell surface markers. The later preplated cells, 96 hours or later (PP6), are regarded as adult stem cells (Figure 2). The late preplate cells appear small, round, and translucent at the beginning of their isolation and can be further characterized by flow cytometry or immunocytochemistry for their expression of stem cell antigen 1 (Sca1), CD34, fetal liver kinase 1 (Flk1), and other stem cell markers (Figure 3). The isolated stem cells have the capacity for self-renewal and experimental studies have demonstrated their multipotency through their differentiation into the three germ layers: mesoderm, ectoderm, and endoderm 9. Multiple investigations have also revealed that these stem cells differentiate into cells of the mesoderm lineage including osteocytes, adipocytes, chondrocytes, and hematopoietic cells 6,8. Other studies have demonstrated that the adult stem cells differentiate into ectoderm cell lineages through their expression of neuronal and glial cell markers and their ability to improve limb function after the peripheral nerve has been damaged 10. These isolated adult stem cells have been beneficial for repairing injured and diseased musculoskeletal tissues, and other related in vivo studies have been performed on other tissues including heart, liver, and spinal cord as well as specific medical conditions like small intestinal submucosa and bladder to treat stress urinary incontinence 9. <img src="/files/ftp_upload/2011/2011fig1.jpg" alt="Figure 1" /> Figure 1. <img src="/files/ftp_upload/2011/2011fig2.jpg" alt="Figure 2" /> Figure 2. <img src="/files/ftp_upload/2011/2011fig3.jpg" alt="Figure 3" /> Figure 3.

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		<th>Comment</th>
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<td>DMEM</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>#11995-073</td>
<td>&nbsp;</td>
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<td>FBS</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>#10437-028</td>
<td>&nbsp;</td>
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<td>Heat-inactivated horse serum</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>#26050-088</td>
<td>&nbsp;</td>
<tr>
<td>Chick embryo extract</td>
<td>&nbsp;</td>
<td>Accurate Chemical</td>
<td>#CE650T-10</td>
<td>&nbsp;</td>
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<td>100U ml penicillin/streptomycin</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>#15140-122</td>
<td>&nbsp;</td>
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<td>Dulbecco&#x2019;s PBS</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>#14190-250</td>
<td>&nbsp;</td>
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<td>Hank&#x2019;s Buffered Salt Solution</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>#24020-117</td>
<td>&nbsp;</td>
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<td>Collagenase type XI 0.2%(wt/vol)</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>#C7657</td>
<td>&nbsp;</td>
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<td>Dispase2.4U ml</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>#17105-041</td>
<td>&nbsp;</td>
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<td>Trypsin-EDTA0.5%(wt/vol) (10x;5g liter trypsin (1:250)</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>#15400-054</td>
<td>&nbsp;</td>
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<td>Collagen for coating flask : Type I collagen derived from calf skin 0.1 g liter</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>#C-9791</td>
<td>&nbsp;</td>
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<td>DMSO</td>
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isolating stem cells from soft musculoskeletal tissues

Adult stem cells have long been discussed in regards to their application in regenerative medicine. Adult stem cells have generated a great deal of excitement for treating injured and diseased tissues due to their impressive capabilities to undergo multi-lineage cell differentiation and their self-renewal ability. Most importantly, these qualities have made them advantageous for use in autologous cell transplantation therapies. The current protocol will introduce the readers to the modified preplate technique where soft tissues of the musculoskeletal system, e.g. tendon and muscle, are 1st enzymatically dissociated and then placed in collagen coated flasks with medium. The supernatant, which is composed of medium and the remaining floating cells, is serially transferred daily to new flasks. The stem cells are the slowest to adhere to the flasks which is usually takes 5-7 days (serial transfers or preplates) . By using this technique, adult stem cells present in these tissues can be easily harvested through fairly non-invasive procedures.

Watch this Scientific Journal Video about Isolating Stem Cells from Soft Musculoskeletal Tissues at JoVE.com

Isolating Stem Cells from Soft Musculoskeletal Tissues

Isolating adult stem cells from musculoskeletal soft tissues based on the cell's adherence speed to flask.

Adult stem cells have long been discussed in regards to their application in regenerative medicine. Adult stem cells have generated a great deal of ...

isolating-stem-cells-from-soft-musculoskeletal-tissues

Nanyang Technological University

Research

JoVE Journal

Biology

13.3K Views.  Stem Cell Research Center, Childrens Hospital of Pittsburgh of UPMC. Isolating adult stem cells from musculoskeletal soft tissues based on the cell's adherence speed to flask.

Video: Isolating Stem Cells from Soft Musculoskeletal Tissues

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 ...

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 ...

Derivation of Mouse Trophoblast Stem Cells from Blastocysts

Specification of the trophectoderm is one of the earliest differentiation events of mammalian development. The trophoblast lineage derived from the trophectoderm mediates implantation and generates the fetal part of the placenta. As a result, the development of this lineage is essential for embryo survival. Derivation of trophoblast stem (TS) cells from mouse blastocysts was first described by Tanaka et al. 1998. The ability of TS cells to preserve the trophoblast specific property and their expression of stage- and cell type-specific markers after proper stimulation provides a valuable model system to investigate trophoblast lineage development whereby recapitulating early placentation events. Furthermore, trophoblast cells are one of the few somatic cell types undergoing natural genome amplification. Although the molecular pathways underlying trophoblast polyploidization have begun to unravel, the physiological role and advantage of trophoblast genome amplification remains largely elusive. The development of diploid stem cells into polyploid trophoblast cells in culture makes this ex vivo system an excellent tool for elucidating the regulatory mechanism of genome replication and instability in health and disease. Here we describe a protocol based on previous reports with modification published in Chiu et al. 2008.

In this video, we demonstrate the isolation of mouse blastocysts and the derivation of trophoblast stem cells from blastocysts. We also describe conditions for maintenance of the stem cell property as well as induction of differentiation in culture.

Specification of the trophectoderm is one of the earliest differentiation events of mammalian development. The trophoblast lineage derived from the ...

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 of Retinal Stem Cells from the Mouse Eye

The adult mouse retinal stem cell (RSC) is a rare quiescent cell found within the ciliary epithelium (CE) of the mammalian eye1,2,3. The CE is made up of non-pigmented inner and pigmented outer cell layers, and the clonal RSC colonies that arise from a single pigmented cell from the CE are made up of both pigmented and non-pigmented cells which can be differentiated to form all the cell types of the neural retina and the RPE. There is some controversy about whether all the cells within the spheres all contain at least some pigment4; however the cells are still capable of forming the different cell types found within the neural retina1-3. In some species, such as amphibians and fish, their eyes are capable of regeneration after injury5, however; the mammalian eye shows no such regenerative properties. We seek to identify the stem cell in vivo and to understand the mechanisms that keep the mammalian retinal stem cells quiescent6-8, even after injury as well as using them as a potential source of cells to help repair physical or genetic models of eye injury through transplantation9-12. Here we describe how to isolate the ciliary epithelial cells from the mouse eye and grow them in culture in order to form the clonal retinal stem cell spheres. Since there are no known markers of the stem cell in vivo, these spheres are the only known way to prospectively identify the stem cell population within the ciliary epithelium of the eye.

In this video, we will demonstrate how to isolate retinal stem cells from the ciliary epithelium of the mouse eye and grow them in culture to form clonal retinal spheres. The spheres that are isolated possess the cardinal properties of stem cells: self-renewal and multipotentiality.

The adult mouse retinal stem cell (RSC) is a rare quiescent cell found within the ciliary epithelium (CE) of the mammalian eye1,2,3. The CE is made up of ...

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 ...

Generation of Mice Derived from Induced Pluripotent Stem Cells

The production of induced pluripotent stem cells (iPSCs) from somatic cells provides a means to create valuable tools for basic research and may also produce a source of patient-matched cells for regenerative therapies. iPSCs may be generated using multiple protocols and derived from multiple cell sources. Once generated, iPSCs are tested using a variety of assays including immunostaining for pluripotency markers, generation of three germ layers in embryoid bodies and teratomas, comparisons of gene expression with embryonic stem cells (ESCs) and production of chimeric mice with or without germline contribution2. Importantly, iPSC lines that pass these tests still vary in their capacity to produce different differentiated cell types2. This has made it difficult to establish which iPSC derivation protocols, donor cell sources or selection methods are most useful for different applications.
The most stringent test of whether a stem cell line has sufficient developmental potential to generate all tissues required for survival of an organism (termed full pluripotency) is tetraploid embryo complementation (TEC)3-5. Technically, TEC involves electrofusion of two-cell embryos to generate tetraploid (4n) one-cell embryos that can be cultured in vitro to the blastocyst stage6. Diploid (2n) pluripotent stem cells (e.g. ESCs or iPSCs) are then injected into the blastocoel cavity of the tetraploid blastocyst and transferred to a recipient female for gestation (see Figure 1). The tetraploid component of the complemented embryo contributes almost exclusively to the extraembryonic tissues (placenta, yolk sac), whereas the diploid cells constitute the embryo proper, resulting in a fetus derived entirely from the injected stem cell line.
Recently, we reported the derivation of iPSC lines that reproducibly generate adult mice via TEC1. These iPSC lines give rise to viable pups with efficiencies of 5-13%, which is comparable to ESCs3,4,7 and higher than that reported for most other iPSC lines8-12. These reports show that direct reprogramming can produce fully pluripotent iPSCs that match ESCs in their developmental potential and efficiency of generating pups in TEC tests. At present, it is not clear what distinguishes between fully pluripotent iPSCs and less potent lines13-15. Nor is it clear which reprogramming methods will produce these lines with the highest efficiency. Here we describe one method that produces fully pluripotent iPSCs and "all- iPSC" mice, which may be helpful for investigators wishing to compare the pluripotency of iPSC lines or establish the equivalence of different reprogramming methods.

Generating induced pluripotent stem cell (iPSC) lines produces lines of differing developmental potential even when they pass standard tests for pluripotency. Here we describe a protocol to produce mice derived entirely from iPSCs, which defines the iPSC lines as possessing full pluripotency1.

The production of induced pluripotent stem cells (iPSCs) from somatic cells provides a means to create valuable tools for basic research and may also ...

Isolating Primary Melanocyte-like Cells from the Mouse Heart

We identified a novel population of melanocyte-like cells (also known as cardiac melanocytes) in the hearts of mice and humans that contribute to atrial arrhythmia triggers in mice. To investigate the electrical and biological properties of cardiac melanocytes we developed a procedure to isolate them from mouse hearts that we derived from those designed to isolate neonatal murine cardiomyocytes. In order to obtain healthier cardiac melanocytes suitable for more extensive patch clamp or biochemical studies, we developed a refined procedure for isolating and plating cardiac melanocytes based on those originally designed to isolate cutaneous melanocytes. The refined procedure is demonstrated in this review and produces larger numbers of healthy melanocyte-like cells that can be plated as a pure population or with cardiomyocytes.

In this protocol, we identified a novel population of melanocyte-like cells (also known as cardiac melanocytes) in the hearts of mice and humans that contribute to atrial arrhythmia triggers in mice.&#160;

We identified a novel population of melanocyte-like cells (also known as cardiac melanocytes) in the hearts of mice and humans that contribute to atrial ...

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.

Na&#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.

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

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 ...