Die Autoren danken Andrea Axtell, Satoshi Itoh, MD, Jeff Velotta, MD, Grant Hoyt, Robert C. Robbins, MD, Jin Yu, MD, Tim Doyle, PhD, und die Stanford Small Animal Imaging Core für die technische Unterstützung. Die Autoren danken AM Bickford, Inc. für die Unterstützung der tierärztlichen Einrichtungen. Diese Arbeit wurde durch Forschungsstipendien der National Institutes of Health (R01 HL-75774, R01 CA098303, R21 HL085743, 1K12 HL087746), der California Tobacco Related Disease Research Program der University of California (15IT-0257 und 1514RT-0169) unterstützt und das California Institute for Regenerative Medicine (RS1-00183). NH wird durch ein Stipendium der American Heart Association unterstützt. kann Heart Association.

1. Differenzierung von murinen ES-Zellen in Endothelzellen <ol><li> Das Protokoll zur Differenzierung von ES-Zellen in Endothelzellen wird an anderer Stelle beschrieben ist nicht der Schwerpunkt dieses Protokoll 2,3. Kurz gesagt, werden die Zellen erlaubt, zu unterscheiden, und die Zellen, die positiv für die endotheliale Marker wie CD31 oder vascular endothelial cadherin (VE-Cadherin) werden dann mittels Fluoreszenz-activated cell sorting (FACS) gereinigt. </li></ol> 2. Der Bau des Double Fusion Reporter Gene und Lentivirale Transduktion <ol><li> Biolumineszenz kann verwendet werden, um Zellen, die geändert werden, um Reporter-Gene wie Glühwürmchen-Luciferase (fluc) exprimieren, sind zu verfolgen. Für diese Anwendung enthalten unsere Zellen sowohl Schwankungen und verbesserte grün fluoreszierendes Protein (eGFP) Fusionsgen unter der Kontrolle eines internen Ubiquitin-Promotor. Um die Zellen zu verändern, das Transgen lentiviralen Vektor, der Schlüssel optimiert genetische Elemente zu erfüllen bio-Sicherheitskriterien sowie erhöhte Transduktionseffizienz kann PFU-FG-Vektor in unserem Labor Durchführung der Schwan-eGFP Fusion Reportergens entwickelt, um stabil zu werden Transduktion der Zellen nach Differenzierung. Diese Fusionskonstrukt ermöglicht sowohl Biolumineszenz und Fluoreszenz-Tracking der transplantierten Zellen. Das Verfahren zur Erzeugung von Viruspartikeln, Transduktion und Produktion von markierten Zellen, die zum Ausdruck Reportergene anderswo 4 beschrieben. </li></ol> 3. Die Transplantation von ESC-derived Endothelzellen der ischämischen Hinterlauf <ol><li> Beginnen Sie den Vorgang, indem man eine Maus, die hinteren Gliedmaßen Ischämie für die Zell-Transplantation unterzogen wurde. Dazu platzieren Sie den Mauszeiger in die Narkose Kammer mit 1-3% Isofluran in 100% Sauerstoff bei einer Durchflussrate von 1l/min. </li><li> Lassen Sie die Maus in die Induktion Kammer, bis es reagiert auf äußere Reize ist. Dann entfernen Sie das Tier von der Induktion Kammer. </li><li> Dann setzen Sie das Tier in Rückenlage auf dem OP-Tisch und verbinden Sie es mit einem kontinuierlichen Strom von 1-3% Isofluran in 100% Sauerstoff bei einer Durchflussrate von 1l/min. </li><li> Wischen Sie die Haut der hinteren Gliedmaßen mit drei wechselnden betadine und Alkohol scheuert. </li><li> Sobald die Haut wird gereinigt, erhalten eine Million ESC-derived Endothelzellen in 30 ul Phosphat-gepufferter Kochsalzlösung (PBS). Legen Sie diese Zellen in einer 28-Gauge-Nadel. </li><li> Wenn die Zellen bereit sind, heben und erweitern das Hinterbein besser visualisieren die Position des M. gastrocnemius. Während die Bein ist gestreckt, die Nadel durch die Haut in das darunter liegende Muskulatur. Achten Sie darauf, nicht bis auf die Knochen Ansatz. Sanft und langsam injizieren die 30 ul Zelle Mischung in die gastrocnemius. Für die intramuskuläre Injektion von 30 ul in der Nähe der Grenze von Volumen, das injiziert werden können. Daher sind 28-gauge Insulinspritzen bevorzugt, weil nach unserer Erfahrung, sie den Verlust Volumen in Spritzen-Nadeln zu beseitigen. </li><li> Nach der Injektion abgeschlossen ist, kehren die Maus, um die Erholung Käfig und überwachen sie kontinuierlich bis wach. Lassen Sie das Tier für mehrere Stunden erholen und fahren Sie dann mit der in vivo Biolumineszenz-Bildgebung der transplantierten Zellen. </li></ol> 4. Biolumineszenz-Bildgebung des ESC-derived Endothelzellen in vivo <ol><li> Die transplantierten ESC-derived Endothelzellen Zellen wurden modifiziert, um sowohl die Schwankungen und die eGFP-Fusionsgen unter der Kontrolle eines internen Ubiquitin-Promotor auszudrücken. Daher kann Biolumineszenz verwendet werden, um die Zellen innerhalb der ischämischen Hinterlauf zu verfolgen. </li><li> Zu Beginn dieses Schrittes auf die Biolumineszenz-Bildgebung und Wohnen Bildaufnahme-Software ab. Dann initialisieren den Erwerb und die Maße des Gesichtsfeldes. </li><li> Als nächstes legen Sie schwarze matte Papier auf die Bildgebung Feld Hintergrund-Emissionen zu absorbieren. </li><li> Sobald die Bildgebung Kiste ist fertig, legen Sie die Maus in die Narkose Kammer mit 1-3% Isofluran in Sauerstoff am Ausgang des 1l/min. Lassen Sie die Maus in die Induktion Kammer, bis es reagiert auf äußere Reize ist. Dann entfernen Sie das Tier von der Induktion Kammer. </li><li> Entfernen Sie das Haar von beiden Hinterbeine mit einem elektrischen Rasierer wie nötig. </li><li> Inject 10 l D-Luciferin pro Gramm Körpergewicht in die Bauchhöhle. Die D-Luciferin ist im Voraus zu gefiltert Stammlösungen von 15 mg / mL in PBS hergestellt. </li><li> Sobald das Luciferin injiziert wird, legen Sie das Tier in der Imaging-Box über das schwarze Papier in der Rückenlage, verbunden mit einem kontinuierlichen Fluss von Isofluran. </li><li> Platzieren Tier in Imaging-Box und die Verbindung mit Isofluran. </li><li> Start, um Bilder für 10-60 Sekunden zu erwerben, um eine optimale Belichtungszeit für die das Bild nicht gesättigt ist zu bestimmen. Wenn das Bild gesättigt, reduzieren Sie die Belichtungszeit. Wenn die Biolumineszenz-Signal ist sehr schwach, erhöhen Sie die Belichtungszeit. </li><li> Using die optimale Belichtungszeit, weiterhin den Erwerb Bilder alle 1-3 Minuten, bis das Signal das Maximum erreicht und dann verschwindet. Wenn Akquisition abgeschlossen ist, speichern Sie die Datei. </li><li> Um die Daten analysieren, wählen Sie Regions of Interest (ROI), dass der Injektionsstelle zu decken. Als Negativ-Kontrolle, kann eine ähnliche ROI für die nicht-operierten Bein ausgewählt werden. Mit der Software, messen die gesamte Ausstrahlung, die in Einheiten von Photonen / Sekunde / cm 2 / Steradiant (p / s / cm 2 / sr) ausgedrückt wird, für die ROIs für jeden Zeitpunkt. Der maximale Wert sollte in der endgültigen Daten verwendet werden. Die Daten können auch an Excel-Tabelle für die zukünftige Verwendung exportiert werden. </li><li> Sobald alle Daten erfasst, kehren die Tiere zur Erholung Käfig und überwachen kontinuierlich, bis das Tier erwacht. </li><li> Wiederholen Sie diesen Vorgang, um die Zellen im Laufe der Zeit zu verfolgen. </li><li> Bei einem gewünschten Zeitpunkt kann das Tier für die Beurteilung von Gewebe-Funktion eingeschläfert werden. </li></ol> 5. Repräsentative Ergebnisse <img src="/files/ftp_upload/old/1034_2009_1_22_4/figure 1.png" alt="Abbildung 1" width="600" height="600" /> Ein Vertreter Biolumineszenz Bild von transplantierten Zellen in der linken Hinterlauf ischämischen ist in Abbildung 1 dargestellt. Bei der Aufnahme der Biolumineszenz, wird die Intensität, mit der Zeit zunehmen, und der maximale Wert während der Zeit natürlich erhalten sollte als der letzte Wert gemeldet werden.

<ol>
	<li>Niiyama, H., Huang, N. F., Rollins, M., Cooke, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Murine+model+of+hindlimb+ischemia.">Murine model of hindlimb ischemia.</a> JoVE. , (2008).</li><li>Levenberg, S., Golub, J. S., Amit, M., Itsakovitz-Eldor, J., Langer, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial+cells+derived+from+human+embryonic+stem+cells.">Endothelial cells derived from human embryonic stem cells.</a> Proc. Natl. Acad. Sci. U.S.A. 99, 4391-4396 (2002).</li><li>Yamashita, J., Itoh, H., Hirashima, M., Ogawa, M., Nishikawa, S., Yurugi, T., Naito, M., Nakao, K., Nishikawa, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flk1-positive+cells+derived+from+embryonic+stem+cells+serve+as+vascular+progenitors.">Flk1-positive cells derived from embryonic stem cells serve as vascular progenitors.</a> Nature. 408, 926-926 (2000).</li><li>De, A., Yaghoubi, S. S., Gambhir, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Applications+of+lentiviral+vectors+in+noninvasive+molecular+imaging.">Applications of lentiviral vectors in noninvasive molecular imaging.</a> Methods Mol Biol. 433, 177-202 (2008).</li><li>Niiyama, H., Kai, H., Yamamoto, T., Shimada, T., Sasaki, K., Murohara, T., Egashira, K., Imaizumi, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Roles+of+endogenous+monocyte+chemoattractant+protein-1+in+ischemia-induced+neovascularization.">Roles of endogenous monocyte chemoattractant protein-1 in ischemia-induced neovascularization.</a> J. Am. Coll. Cardiol. 44, 661-666 (2004).</li><li>Cook, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+anatomy+of+the+laboratory+mouse.">The anatomy of the laboratory mouse.</a> , (1976).</li><li>Contag, P. R., Olomu, I. N., Stevenson, D. K., Contag, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioluminescent+indicators+in+living+mammals.">Bioluminescent indicators in living mammals.</a> Nature Med. 4, 245-247 (1998).</li><li>Ray, P., De, A., Min, J. J., Tsien, R. Y., Gambhir, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+tri-fusion+multimodality+reporter+gene+expression+in+living+subjects.">Imaging tri-fusion multimodality reporter gene expression in living subjects.</a> Cancer Res. 64, 1323-1330 (2004).</li><li>Huang, N. F., Lee, R. J., Li, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemical+and+physical+regulation+of+stem+cells+and+progenitor+cells:+potential+for+cardiovascular+tissue+engineering.">Chemical and physical regulation of stem cells and progenitor cells: potential for cardiovascular tissue engineering.</a> Tissue Eng. 13, 1809-1823 (2007).</li><li>Cao, F., Lin, S., Xie, X., Ray, P., Patel, M., Zhang, X., Drukker, M., Dylla, S. J., Connolly, A. J., Chen, X., Weissman, I. L., Gambhir, S. S., Wu, 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=In+vivo+visualization+of+embryonic+stem+cell+survival,+proliferation,+and+migration+after+cardiac+delivery.">In vivo visualization of embryonic stem cell survival, proliferation, and migration after cardiac delivery.</a> Circulation. 113, 1005-1114 (2006).</li><li>Wilson, K., Yu, J., Lee, A., Wu, 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=In+vitro+and+in+vivo+bioluminescence+reporter+gene+imaging+of+human+embryonic+stem+cells.">In vitro and in vivo bioluminescence reporter gene imaging of human embryonic stem cells.</a> J Vis Exp. , (2008).</li></ol>

ESZ sind eine vielversprechende Quelle Zelle für die Behandlung von Gewebe-Ischämie aufgrund ihrer Plastizität der Differenzierung und ihre Fähigkeit, sich zu erheben, um Zelllinien aus aller drei Keimblätter, einschließlich Endothelzellen geben. Zur Überwindung der ethischen Bedenken mit ESC verbunden sind, können induzierte pluripotente Stammzellen (IPSCs) eine Alternative pluripotente Stammzelle Quelle, die die ethischen Bedenken überwindet werden. Neben WSR können adulte Stammzellen, wie endotheliale Vorläuferzellen (EPC) und...

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		<th>Material Name</th>
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		<th>Catalogue Number</th>
		<th>Comment</th>
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<tr>
<td>Surgical tools</td>
<td>Tool</td>
<td>Fine Science Tools</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
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<td>Syringe needle</td>
<td>Tool</td>
<td>BD</td>
<td>&nbsp;</td>
<td>28G insulin syringe is preferred</td>
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<td>Phosphate Buffered Saline </td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
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<td>D-luciferin</td>
<td>Reagent</td>
<td>Biosynth International, Inc</td>
<td>&nbsp;</td>
<td>Prepare D-luciferin in advance into filtered stock solutions of 15 mg/mL in PBS</td>
</tr>
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<td>IVIS 200 Bioluminescence imaging system and acquisition software </td>
<td>Equipment</td>
<td>Xenogen Corporation</td>
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embryonic stem cell-derived endothelial cells for treatment of hindlimb ischemia

Periphere arterielle Verschlusskrankheit (pAVK) ergibt sich aus Verengung der peripheren Arterien, die sauerstoffreiches Blut und Nährstoffen zu versorgen, um die Beine und Füße, Ursachen dieser Erkrankung Symptome wie Claudicatio intermittens (Schmerzen beim Gehen), schmerzhafte ischämische Geschwüre oder sogar Gliedmaßen-bedrohlichen Gangrän. Es wird allgemein angenommen, dass das vaskuläre Endothel, einer Monoschicht aus Endothelzellen, die der luminalen Oberfläche von Blut-und Lymphgefäße investiert, eine dominierende Rolle spielt in der vaskulären Homöostase und vaskuläre Regeneration. Als Ergebnis Stammzellen-basierten Regeneration des Endothels kann ein viel versprechender Ansatz zur Behandlung von PAD werden. In diesem Video zeigen wir die Transplantation von embryonalen Stammzellen (ESC)-abgeleiteten Endothelzellen zur Behandlung von einseitigen hindimb Ischämie als ein Modell der PAD, durch nicht-invasive Verfolgung der Zelle Homing und das Überleben von Biolumineszenz-Bildgebung verfolgt. Die spezifischen Materialien und Verfahren für die Zell-Liefer-und Imaging beschrieben. Dieses Protokoll folgt eine weitere Veröffentlichung in der Beschreibung der Induktion der hinteren Gliedmaßen Ischämie durch Niiyama et al. 1

Watch this Scientific Journal Video about Embryonic Stem Cell-Derived Endothelial Cells for Treatment of Hindlimb Ischemia at JoVE.com

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

Das chirurgische Verfahren für die Lieferung von embryonalen Stammzellen abgeleitete Endothelzellen der ischämischen Hinterlauf gezeigt wird, mit nicht-invasive Tracking durch Biolumineszenz-Bildgebung.

Embryonale Stammzellen gewonnenen Endothelzellen zur Behandlung von Ischämie Hinterlauf

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

embryonic-stem-cell-derived-endothelial-cells-for-treatment-hindlimb

Research

JoVE Journal

Biology

11.7K Aufrufe.  Stanford University. Das chirurgische Verfahren für die Lieferung von embryonalen Stammzellen abgeleitete Endothelzellen der ischämischen Hinterlauf gezeigt wird, mit nicht-invasive Tracking durch Biolumineszenz-Bildgebung.

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

Propagation of Human Embryonic Stem (ES) Cells

Propagation of Human Embryonic Stem ES Cells

Vermehrung von humanen embryonalen Stammzellen (ES-Zellen)

Forschung

Biologie

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.

Ableitung von hämatopoetischen Stammzellen aus embryonalen Stammzellen der Maus

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.

Gewinnung menschlicher embryonaler Stammzellen durch Immunosurgery

The ability of human embryonic stem cells to self-renew and differentiate into all cell types of 
the body suggests that they hold great promise for both ...

Probing for Mitochondrial Complex Activity in Human Embryonic Stem Cells

Mitochondria are cytoplasmic organelles that have a primary role in cellular metabolism and homeostasis, regulation of the cell signaling network, and programmed cell death. Mitochondria produce ATP, regulate the cytoplasmic redox state and Ca2+ balance, catabolize fatty acids, synthesize heme, nucleotides, steroid hormones, amino acids, and help assemble iron-sulfur clusters in proteins. Mitochondria also have an essential role in heat production. Mutations of the mitochondrial genome cause several types of human disorder. The accumulation of mtDNA mutations correlates with aging and is suspected to have an important role in the development of cancer. Due to their vitally important role in all cell types, the function of mitochondria must also be critical for stem cells. Key advances have been made in our understanding of stem cell viability, proliferation, and differentiation capacity. But the functional activity of stem cells, in particular their energy status, was not yet been studied in detail. Almost nothing is known about the mitochondrial properties of human embryonic stem cells (hESCs) and their differentiated precursor progeny. One way to understand and evaluate the role of mitochondria in hESC function and developmental potential is to directly measure the activity of mitochondrial respiratory complexes. Here, we describe high resolution clear native gel electrophoresis and subsequent in gel activity visualization as a method for analyzing the five respiratory chain complexes of hESCs.

In this video, we will show you how the mitochondrial respiratory chain complexes of human embryonic stem cells can be analyzed using in gel activity assays.

Probing für Mitochondriale komplexe Aktivität in humanen embryonalen Stammzellen

Mitochondria are cytoplasmic organelles that have a primary role in cellular metabolism and homeostasis, regulation of the cell signaling network, and ...

Chromatin Immunoprecipitation from Human Embryonic Stem Cells

The functional and structural complexity of the myriad of cells in metazoan organisms arises from a small number of stem cells. Stem cells are characterized by two fundamental properties: self-renewal and multipotency that allows a stem cell to differentiate into virtually any cell type 1. The progression stem cell to differentiated cell is characterized by loss of multipotency, structural and morphological changes and the hierarchic activity of transcription factors and signaling molecules, whose activities establish and maintain cell-type specific gene expression patterns. At the molecular level, cell differentiation involves dynamic changes of the structure and composition of chromatin and the detection of those dynamic changes can provide valuable insights into the functional features of stem cells and the cell differentiation process 2,3. Chromatin is a highly compacted DNA-protein complex that forms when cells package chromosomal DNA with proteins, mainly histones 4. Stemcellness and cell differentiation has been correlated with the presence of specific arrays of regulatory proteins such as epigenetic factors, histone variants, and transcription factors 2,3,5.
 Chromatin immunoprecipitation (ChIP) provides a valuable method to monitor the presence of RNA, proteins, and protein modifications in chromatin 6,7. The comparison of chromatin from different cell types can elucidate dynamic changes in protein-chromatin associations that occur during cell differentiation.
Chromatin immunoprecipitation involves the purification of in vivo cross-linked chromatin. The isolated chromatin is reduced to smaller fragments by enzymatic digestion or mechanical force. Chromatin fragments are precipitated using specific antibodies to target proteins or protein and DNA modifications. The precipitated DNA or RNA is purified and used as a template for PCR or DNA microarray based assays. Prerequisites for a successful ChIP are high quality antibodies to the desired antigen and the availability of chromatin from control cells that do not express the target molecule. ChIP can correlate the presence of proteins, protein and RNA modifications, and RNA with specific target DNA, and depending on the choice of outread tool, detects the association of target molecules at specific target genes or in the context of an entire genome. The comparison of the distribution of proteins in the chromatin of differentiating cells can elucidate the dynamic changes of chromatin composition that coincide with the progression of cells along a cell lineage.

The differentiation of ESC coincides with cell-type specific changes in the structure and composition of chromatin. The detection of those changes provides valuable insights into the mechanisms that define stemcellness and cell differentiation. Chromatin immunoprecipitation (ChIP) represents a valuable method to dissect the molecular mechanisms underlying stem cell differentiation.

Chromatin Immunopräzipitation von humanen embryonalen Stammzellen

The functional and structural complexity of the myriad of cells in metazoan organisms arises from a small number of stem cells. Stem cells are ...

Murine Model of Hindlimb Ischemia 

In the United States, peripheral arterial disease (PAD) affects about 10 million individuals, and is also prevalent worldwide. Medical therapies for symptomatic relief are limited. Surgical or endovascular interventions are useful for some individuals, but long-term results are often disappointing. As a result, there is a need for developing new therapies to treat PAD. The murine hindlimb ischemia preparation is a model of PAD, and is useful for testing new therapies. When compared to other models of tissue ischemia such as coronary or cerebral artery ligation, femoral artery ligation provides for a simpler model of ischemic tissue. Other advantages of this model are the ease of access to the femoral artery and low mortality rate. 
In this video, we demonstrate the methodology for the murine model of unilateral hindimb ischemia. The specific materials and procedures for creating and evaluating the model will be described, including the assessment of limb perfusion by laser Doppler imaging. This protocol can also be utilized for the transplantation and non-invasive tracking of cells, which is demonstrated by Huang et al.1.

Murine Model of Hindlimb Ischemia

The surgical procedure for induction of unilateral hindlimb ischemia is demonstrated, with confirmation of ischemia by laser Doppler perfusion imaging.

Mausmodell der hinteren Gliedmaßen Ischämie

In the United States, peripheral arterial disease (PAD) affects about 10 million individuals, and is also prevalent worldwide.  Medical therapies for ...

Chromosomal Spread Preparation of Human Embryonic Stem Cells for Karyotyping

Although human embryonic stem cells (hESC) have been shown to present a stable diploid karyotype 1, many studies have reported that depending on culture conditions they become prone to acquire chromosomal anomalies such as addition of whole or parts of chromosomes. Indeed, during long-term culture, karyotypic alterations are observed when enzymatic or chemical dissociation are used 2,3,4, while manual dissection of colonies for passaging retains a stable karyotype 5. Besides, changes in the environment such as the removal of feeder cells also seem to compromise the genetic integrity of hESC 3,6. Once chromosomal alterations could affect cellular physiology, the characterization of the genetic integrity of hESC in vitro is crucial considering hESC as an essential tool in embryogenesis studies and drug testing. Furthermore, for future therapeutic purposes chromosomal changes are a real concern as it is frequently associated to carcinogenesis.
Here we show a simple and useful method to obtain high quality chromosome spreads for subsequent analysis of chromosome set by G-banding, FISH, SKY or CGH techniques 7,8. We recommend checking the chromosomal status routinely with intervals of 5 passages in order to monitor the appearance of translocations and aneuploidies
Priscila Britto and Rafaela Sartore contributed equally to the paper.

Karyotyping is a simple and useful technique widely used for detecting genetic alterations. Here we describe a step by step protocol for chromosome spread preparation of human embryonic stem cells for monitoring the chromosomal status of these cells maintained in culture.

Chromosomale Spread-Vorbereitung von humanen embryonalen Stammzellen für die Karyotypisierung

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

Isolation and Derivation of Mouse Embryonic Germinal Cells

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

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

Isolation und Ableitung von embryonalen Maus-Keimzellen

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

Differentiation of Embryonic Stem Cells into Oligodendrocyte Precursors

Oligodendrocytes are the myelinating cells of the central nervous system. For regenerative cell therapy in demyelinating diseases, there is significant interest in deriving a pure population of lineage-committed oligodendrocyte precursor cells (OPCs) for transplantation. OPCs are characterized by the activity of the transcription factor Olig2 and surface expression of a proteoglycan NG2. Using the GFP-Olig2 (G-Olig2) mouse embryonic stem cell (mESC) reporter line, we optimized conditions for the differentiation of mESCs into GFP+Olig2+NG2+ OPCs. In our protocol, we first describe the generation of embryoid bodies (EBs) from mESCs. Second, we describe treatment of mESC-derived EBs with small molecules: (1) retinoic acid (RA) and (2) a sonic hedgehog (Shh) agonist purmorphamine (Pur) under defined culture conditions to direct EB differentiation into the oligodendroglial lineage. By this approach, OPCs can be obtained with high efficiency (&gt;80%) in a time period of 30 days. Cells derived from mESCs in this protocol are phenotypically similar to OPCs derived from primary tissue culture. The mESC-derived OPCs do not show the spiking property described for a subpopulation of brain OPCs in situ. To study this electrophysiological property, we describe the generation of spiking mESC-derived OPCs by ectopically expressing NaV1.2 subunit. The spiking and nonspiking cells obtained from this protocol will help advance functional studies on the two subpopulations of OPCs.

We describe a small molecule-based protocol for differentiation of mouse embryonic stem cells into oligodendrocyte precursor cells (OPCs). This protocol generates Olig2+NG2+ OPCs with high efficiency by 30 days of differentiation. We also describe a method to generate "spiking" OPCs that can fire action potentials.

Differenzierung von embryonalen Stammzellen in Oligodendrozyten Precursors

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

Efficient Differentiation of Mouse Embryonic Stem Cells into Motor Neurons

Direct differentiation of embryonic stem (ES) cells into functional motor neurons represents a promising resource to study disease mechanisms, to screen new drug compounds, and to develop new therapies for motor neuron diseases such as spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS). Many current protocols use a combination of retinoic acid (RA) and sonic hedgehog (Shh) to differentiate mouse embryonic stem (mES) cells into motor neurons1-4. However, the differentiation efficiency of mES cells into motor neurons has only met with moderate success. We have developed a two-step differentiation protocol5 that significantly improves the differentiation efficiency compared with currently established protocols. The first step is to enhance the neuralization process by adding Noggin and fibroblast growth factors (FGFs). Noggin is a bone morphogenetic protein (BMP) antagonist and is implicated in neural induction according to the default model of neurogenesis and results in the formation of anterior neural patterning6. FGF signaling acts synergistically with Noggin in inducing neural tissue formation by promoting a posterior neural identity7-9. In this step, mES cells were primed with Noggin, bFGF, and FGF-8 for two days to promote differentiation towards neural lineages. The second step is to induce motor neuron specification. Noggin/FGFs exposed mES cells were incubated with RA and a Shh agonist, Smoothened agonist (SAG), for another 5 days to facilitate motor neuron generation. To monitor the differentiation of mESs into motor neurons, we used an ES cell line derived from a transgenic mouse expressing eGFP under the control of the motor neuron specific promoter Hb91. Using this robust protocol, we achieved 51&plusmn;0.8% of differentiation efficiency (n = 3; p &lt; 0.01, Student's t-test)5. Results from immunofluorescent staining showed that GFP+ cells express the motor neuron specific markers, Islet-1 and choline acetyltransferase (ChAT). Our two-step differentiation protocol provides an efficient way to differentiate mES cells into spinal motor neurons.

We developed a new protocol to improve efficiency of in vitro differentiation of mouse embryonic stem cells into motor neurons. The differentiated ES cells acquired motor neurons features as evidenced by expression of neuronal and motor neuron markers using immunohistochemical techniques.

Effiziente Differenzierung von embryonalen Stammzellen der Maus in Motoneuronen

Direct differentiation of embryonic stem (ES) cells into functional  motor neurons represents a promising resource to study disease mechanisms, to  screen ...