This work was funded by the Max Planck Society.

1. Preparation of Matrigel-coated Plates and Media
<ol>
 <li>Preparation of Matrigel-coated plates Matrigel has been found to be a preferred substrate for the attachment of differentiating EBs and also promotes the efficient outgrowth of neurons from these10.
 <ol>
	 <li>Thaw 10 ml of Matrigel overnight on ice.</li>
	 <li>Next day, dilute the jelly-like Matrigel with two volumes of ice-cold DMEM/F-12 and prepare aliquots of 1 ml in prechilled 15 ml conical tubes which may be stored frozen at -20 &deg;C.</li>
 <li>Decide upon a plate format for neuronal differentiation. For instance, as a starting point, we recommend to perform an initial round of differentiation in a 12-well format. Pre-cool four 12-well plates at 4 &deg;C. Dissolve one aliquot of frozen Matrigel by adding 9 ml of pre-chilled DMEM/F-12 followed by pipetting up and down until all the prediluted Matrigel has thawed and dissolved.</li>
 <li>Then, transfer the contents into a new 50 ml tube containing 15 ml of DMEM/F-12 on ice (final Matrigel dilution: 1:75). Then, add 0.5 ml of diluted Matrigel to each well of the pre-cooled 12-well plates. Wrap plates with Parafilm and let stand at RT overnight.</li>
 <li>Next day, transfer plates to 4 &deg;C. Coated plates can be stored for several weeks before use.</li>
 </ol>
 </li>
 <li>Media</li>
</ol>
EB formation medium (~15 ml needed to perform differentiation in one 96-well plate - see Table 1 and scheme in Figure 2): DMEM/F-12 with 0.4% (PVA) 1x N2 1x B27 0.05% BSA 20 ng/ml FGF2 10 &mu;M Y-27632 1x PenStrepGln
Differentiation medium (~30 ml needed to perform differentiation in one 96-well plate, followed by neuron formation in one Matrigel-coated 12-well plate, see Table 1): DMEM/F-12 1x N2 1x B27 0.05% BSA 0.5 &mu;M PD0325901 15 &mu;M SB431542 0.5 &mu;M Dorsomorphin 1x PenStrepGln
2. Forced EB Formation
<ol>
 <li>Grow hPSCs under your preferred feeder-free conditions. We use MEF-conditioned medium on Matrigel-coated 6-well plates15. However, other culture systems such as homemade or commercial defined media should also work. At the time of starting a differentiation experiment, hPSCs should be sub-confluent and actively growing.</li>
 <li>Mechanically remove spontaneously differentiated colonies using a sterile plastic pipette tip under a stereo microscope.</li>
 <li>Wash remaining undifferentiated colonies using PBS, and digest to single cells using Accutase containing 1X Y-27632. Pellet single cells by centrifugation at 200 x g for 2 min, resuspend in a small volume of EB formation medium and determine cell titre using a hematocytometer.</li>
 <li>Add an aliquot of cells to the remaining EB formation medium to result in a titre between 40,000 and 80,000 cells per ml.</li>
 <li>Using a multichannel pipette, transfer 100 &mu;l per well to a 96V-bottom plate, resulting in 4,000 to 8,000 cells per well. Spin 96-well plate in a swing-out plate centrifuge at 400 x g for 1 min to collect cells at the bottom of the wells, and transfer to cell culture incubator. EBs will form overnight, as shown in Figure 1.</li>
</ol>
3. Neuroectoderm Induction
<ol>
 <li>Next day (day 0), collect EBs from 96V plate under a stereo microscope and transfer in a small volume into a 3.5 cm bacterial dish containing 2 ml of differentiation medium. Gently agitate the dish for several seconds to wash the EBs.</li>
 <li>Add 100 &mu;l of differentiation medium per well of an ultra-low-attachment U-bottom 96-well plate. Under a stereomicroscope, transfer EBs in small volumes from the washing dish into the 96U-wells (one EB per well). Place 96U plate into cell culture incubator for 4 days to allow neuroectoderm formation.</li>
</ol>
4. Neuron Formation 
<ol>
 <li>On day 4, prepare a washing dish as in step 3.1 and additionally replace DMEM/F-12 in a pre-warmed Matrigel-coated 12-well plate by differentiation medium (1 ml per well).</li>
 <li>Plating of EBs
 <ol>
	 <li>Collect EBs from 96U plate, wash these as above, and carefully seed them one by one into wells of the Matrigel-coated 12-well plate (about 8 EBs per well): EBs should be equally distributed within the wells to allow undisturbed outgrowth of neurons over the next days (see "day 5" image in Figure 2).</li>
	 <li>Before transfer of the 12-well plate back into the incubator, allow EBs to loosely attach for around 10 min at RT. Then, carefully transfer 12-well plate to cell culture incubator. Neurons will grow out from the plated EBs in a radial manner within the next 4 days, as shown in Figure 2 ("day 8" image on the right).</li>
 </ol>
 </li>
</ol>
5. Neuron Formation as Monolayers
<ol>
 <li>As an alternative to the steps of point 4), at day 4 of the procedure, collect EBs into a 3.5 cm bacterial dish containing 2 ml of differentiation medium, then transfer EBs in a small volume to a PBS-containing dish, and then into another dish containing Accutase.</li>
 <li>Let digest to single cells, centrifuge at 200 x g for 2 min, resuspend in a small volume of differentiation medium and determine cell titre using a hematocytometer. Adjust titre to 1-2X106 cells per ml using differentiation medium (without Y-27632).</li>
 <li>Plate cells out in pre-warmed Matrigel-coated 12-well plate (1 ml per well), and transfer to cell culture incubator. Neuron formation as monolayers was observed between days 7 to 8 (Figure 3C). It should be noted, however, that this monolayer variant of the procedure is not fully optimized with regards to cell survival and most suitable substrate.</li>
</ol>

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A., Ladewig, J., Brustle, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+rosette-type,+self-renewing+human+ES+cell-derived+neural+stem+cell+with+potential+for+in+vitro+instruction+and+synaptic+integration.">A rosette-type, self-renewing human ES cell-derived neural stem cell with potential for in vitro instruction and synaptic integration.</a> Proc. Natl. Acad. Sci. U.S.A. 106, 3225-3230 (2009).</li><li>Chambers, S. M., 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=Highly+efficient+neural+conversion+of+human+ES+and+iPS+cells+by+dual+inhibition+of+SMAD+signaling.">Highly efficient neural conversion of human ES and iPS cells by dual inhibition of SMAD signaling.</a> Nat. Biotechnol. 27, 275-280 (2009).</li><li>Lee, 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+and+directed+differentiation+of+neural+crest+stem+cells+derived+from+human+embryonic+stem+cells.">Isolation and directed differentiation of neural crest stem cells derived from human embryonic stem cells.</a> Nat. Biotechnol. 25, 1468-1475 (2007).</li><li>Li, X. 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=Specification+of+motoneurons+from+human+embryonic+stem+cells.">Specification of motoneurons from human embryonic stem cells.</a> Nat. Biotechnol. 23, 215-221 (2005).</li><li>Pera, M. F., 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=Regulation+of+human+embryonic+stem+cell+differentiation+by+BMP-2+and+its+antagonist+noggin.">Regulation of human embryonic stem cell differentiation by BMP-2 and its antagonist noggin.</a> J. Cell Sci. 117, 1269-1280 (2004).</li><li>Smith, J. R., 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=Inhibition+of+Activin/Nodal+signaling+promotes+specification+of+human+embryonic+stem+cells+into+neuroectoderm.">Inhibition of Activin/Nodal signaling promotes specification of human embryonic stem cells into neuroectoderm.</a> Dev. 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No conflicts of interest declared.

Most differentiation protocols involving EB formation from hPSCs, including our previously published procedure10, are based on manual or enzyme-assisted harvesting of hESCs as aggregates, which inevitably leads to heterogeneity in EB sizes. This fact leads to variability in differentiation efficiency with some cell lines, thereby rendering systematic analyses difficult, in particular at a medium throughput scale. Furthermore, manual dissection is labor-intensive which by itself compromises scalability.
...

hPSCs, comprising embryo-derived human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs), are pluripotent meaning that they can give rise to various cell lineages in vitro 1-2. Numerous differentiated cell types have been derived from hESCs to date, supporting the notion that these cells present valuable tools for scientific research and cell-based screening approaches, and hold promise for cell-based therapeutics.
Neuronal differentiation protocols for hESCs are usually complex and time-consuming as they are often based on first inducing overall neural fate, followed by manual isolation of neural progenitors, and subsequent terminal differentiation into a given neuron type of interest3-6. In some regard, this complexity is not surprising and inevitable given that such state-of-the-art directed differentiation protocols tend to stepwise mimic early human development, which is in itself extremely complex. On the other hand, it may in part also reflect our lack of understanding of the underlying molecular processes, resulting in differentiation protocols that are still far from being fully optimized.
With regards to the conversion of undifferentiated hPSCs into neuroectoderm, Pera et al. found that suppression of BMP / SMAD1/5/8 signaling enhances neural induction of hESCs7. Moreover, inactivation of SMAD2/3 signaling has been shown to promote neuroectoderm formation8. Accordingly, combined inactivation of these two pathways tends to lead to more efficient neural induction of hPSCs4,9. More recently, we have shown that a third signaling pathway, FGF/ERK, serves as a strong repressor of the earliest steps of neuroectodermal commitment in hESCs. Conversely, simultaneous repression of all these three pathways lead to near-homogeneous conversion of hESCs into neuroectoderm within just four days10. Subsequently, highly efficient terminal differentiation into functional neurons was observed within eight days. The neurons obtained were likely to be sensory neurons of the peripheral nervous system, which may in part explain their rapid derivation10. Defects in sensory neuron maintenance is regarded a cause of certain human disorders such as familial dysautonomia11. For modeling such diseases based on hiPSC technology12, for further functional characterization, as well as for applied purposes not requiring any particular type of neurons, this differentiation procedure may present a useful basis.
However, the differentiation strategy we originally employed involved formation of embryonic bodies (EBs) from clumps of hESC colonies10, and this resulted in quite a degree of heterogeneity regarding EB sizes, and also appeared to compromise neuron formation efficiency in some cell lines. Moreover, due to the heterogeneity in EB sizes, the ability to systematically test effects of additional growth factors or small molecules during and after neuron formation appeared to be somewhat confounded.
In this report, we adapted our previous procedure to a medium throughput-compatible, forced aggregation-based technique to generate EBs in a highly size-controlled manner, as also shown in other contexts13. Subsequently, the EBs generated in V-shaped wells of 96-well plates were transferred to U-shaped ultra-low attachment 96-well plates, to initiate neuroectoderm formation in suspension. Four days later, the EBs could be plated out giving rise to terminally differentiated neurons at high efficiency and homogeneity. Alternatively, day-4 EBs were dissociated into single cells and plated out as such, which resulted in low-density monolayers of human neurons. Coherent results were thus far obtained with two independently derived hESC lines, HuES6 and NCL3.
As a prerequisite, successful EB formation was strictly dependent on the use of a synthetic polymer, polyvinyl alcohol (PVA), together with ROCK inhibitor Y-27632 known to promote hESC survival13-14. As a result, homogeneity of the EBs formed in 96-V-plates was substantially enhanced compared to formation of EBs as mass cultures based on random splitting techniques. This system thus provides a significantly improved platform for neuroectoderm formation in suspension culture, followed by highly controlled neuron formation under adherent conditions.

<table border="1">
 <tbody>
 <tr>
 <td>Name of the reagent</td>
 <td>Company</td>
 <td>Catalogue number</td>
 <td>Comments </td>
 </tr>
 <tr>
 <td>Matrigel HC</td>
 <td>Becton Dickinson</td>
 <td>354263</td>
 <td>See text for details on handling</td>
 </tr>
 <tr>
 <td>DMEM/F-12</td>
 <td>Life Technologies</td>
 <td>21331-020</td>
 <td></td>
 </tr>
 <tr>
 <td>Poly(vinyl alcohol)</td>
 <td>Sigma</td>
 <td>363170</td>
 <td>Dissolve at 0.4% in DMEM/F-12 using an ultrasonic waterbath / avoid overheating / can be kept at 4 &deg;C for several weeks</td>
 </tr>
 <tr>
 <td>N2 Supplement</td>
 <td>Life Technologies</td>
 <td>17502-048</td>
 <td>100X, store as frozen aliquots</td>
 </tr>
 <tr>
 <td>B27 Supplement</td>
 <td>Life Technologies</td>
 <td>12587-010</td>
 <td>50X, store as frozen aliquots</td>
 </tr>
 <tr>
 <td>Bovine Serum Albumin</td>
 <td>Sigma</td>
 <td>A1595</td>
 <td>10% = 500X, store as frozen aliquots</td>
 </tr>
 <tr>
 <td>L-Glutamine with Penicillin / Streptomycin</td>
 <td>PAA</td>
 <td>P11-013</td>
 <td>Or equivalent</td>
 </tr>
 <tr>
 <td>FGF2</td>
 <td>Peprotech</td>
 <td>100-18B</td>
 <td>Dissolve at 10 &mu;g/ml in 0.1% BSA / PBS = 1000X, store as frozen aliquots</td>
 </tr>
 <tr>
 <td>ROCK inhibitor Y-27632 </td>
 <td>abcamBiochemicals</td>
 <td>Asc-129</td>
 <td>Dissolve at 10 mM in DMSO = 1000X, store as frozen aliquots</td>
 </tr>
 <tr>
 <td>PBS</td>
 <td>PAA</td>
 <td>H15-002</td>
 <td>Or equivalent</td>
 </tr>
 <tr>
 <td>Accutase</td>
 <td>PAA</td>
 <td>L11-007</td>
 <td></td>
 </tr>
 <tr>
 <td>96-well V-bottom plates</td>
 <td>Nunc</td>
 <td>277143</td>
 <td></td>
 </tr>
 <tr>
 <td>PD0325901</td>
 <td>Axon Medchem</td>
 <td>Axon 1408</td>
 <td>Dissolve at 0.5 mM in DMSO = 1000X, store as frozen aliquots</td>
 </tr>
 <tr>
 <td>SB431542</td>
 <td>abcamBiochemicals</td>
 <td>Asc-163</td>
 <td>dissolve at 15 mM in DMSO = 1000X, store as frozen aliquots</td>
 </tr>
 <tr>
 <td>Dorsomorphin</td>
 <td>Santa Cruz</td>
 <td>sc-200689</td>
 <td>dissolve at 0.5 mM in DMSO = 1000X, store as frozen aliquots</td>
 </tr>
 <tr>
 <td>96-well U-bottom ultra-low attachment plates</td>
 <td>Corning</td>
 <td>7007</td>
 <td></td>
 </tr>
 <tr>
 <td>beta-III Tubulin antibody (mouse)</td>
 <td>Sigma</td>
 <td>T8660</td>
 <td>use at 1:1000</td>
 </tr>
 <tr>
 <td>beta-III Tubulin antibody (rabbit)</td>
 <td>Covance</td>
 <td>PRB-435P</td>
 <td>use at 1:2000</td>
 </tr>
 <tr>
 <td>BRN3A (POU4F1) antibody</td>
 <td>Santa Cruz</td>
 <td>sc-8429</td>
 <td>use at 1:500</td>
 </tr>
 <tr>
 	<td></td>
 <td></td>
 <td></td>
 <td>Table 1. Specific reagents and equipment.</td>
 </tr>
 </tbody>
</table>

rapid and efficient generation of neurons from human pluripotent stem cells in a multititre plate format

Existing protocols for the generation of neurons from human pluripotent stem cells (hPSCs) are often tedious in that they are multistep procedures involving the isolation and expansion of neural precursor cells, prior to terminal differentiation. In comparison to these time-consuming approaches, we have recently found that combined inhibition of three signaling pathways, TGF&beta;/SMAD2, BMP/SMAD1, and FGF/ERK, promotes rapid induction of neuroectoderm from hPSCs, followed by immediate differentiation into functional neurons. Here, we have adapted our procedure to a novel multititre plate format, to further enhance its reproducibility and to make it compatible with mid-throughput applications. It comprises four days of neuroectoderm formation in floating spheres (embryoid bodies), followed by a further four days of differentiation into neurons under adherent conditions. Most cells obtained with this protocol appear to be bipolar sensory neurons. Moreover, the procedure is highly efficient, does not require particular expert skills, and is based on a simple chemically defined medium with cost-efficient small molecules. Due to these features, the procedure may serve as a useful platform for further functional investigation as well as for cell-based screening approaches requiring human sensory neurons or neurons of any type.

In our previous report, in line with many others, EBs from hPSCs could be generated simply by replating aggregates upon routine splitting of hPSCs into low-attachment dishes10. This usually results in a wide distribution of resulting EB sizes (Figure 1C, top). Another problem resulting from this is that EBs maintained in suspension tend to aggregate with one another, leading to an even higher heterogeneity of EB sizes. To circumvent these problems, we therefore attempted to generate EBs ...

Watch this Scientific Journal Video about Rapid and Efficient Generation of Neurons from Human Pluripotent Stem Cells in a Multititre Plate Format at JoVE.com

Rapid and Efficient Generation of Neurons from Human Pluripotent Stem Cells in a Multititre Plate Format

Protocols for neuronal differentiation of pluripotent human stem cells (hPSCs) are often time-consuming and require substantial cell culture skills. Here, we have adapted a small molecule-based differentiation procedure to a multititre plate format, allowing simple, rapid, and efficient generation of human neurons in a controlled manner.

Existing protocols for the generation of neurons from human pluripotent stem cells (hPSCs) are often tedious in that they are  multistep procedures ...

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43.5K vistas.  Max Planck Institute for Molecular Biomedicine. Protocolos para la diferenciación neuronal de las células madre humanas pluripotentes (hPSCs) son a menudo mucho tiempo y requieren considerables conocimientos de cultivo de células. Aquí, hemos adaptado una molécula pequeña de un procedimiento basado en una diferenciación a un formato de placa de multititre, que permite la generación sencilla, rápida, y eficiente de las neuronas humanas de una manera controlada.

Video: Rapid and Efficient Generation of Neurons from Human Pluripotent Stem Cells in a Multititre Plate Format

Transfecting and Nucleofecting Human Induced Pluripotent Stem Cells

Genetic modification is continuing to be an essential tool in studying stem cell biology and in setting forth potential clinical applications of human embryonic stem cells (HESCs)1. While improvements in several gene delivery methods have been described2-9, transfection remains a capricious process for HESCs, and has not yet been reported in human induced pluripotent stem cells (iPSCs). In this video, we demonstrate how our lab routinely transfects and nucleofects human iPSCs using plasmid with an enhanced green fluorescence protein (eGFP) reporter. Human iPSCs are adapted and maintained as feeder-free cultures to eliminate the possibility of feeder cell transfection and to allow efficient selection of stable transgenic iPSC clones following transfection. For nucleofection, human iPSCs are pre-treated with ROCK inhibitor11, trypsinized into small clumps of cells, nucleofected and replated on feeders in feeder cell-conditioned medium to enhance cell recovery. Transgene-expressing human iPSCs can be obtained after 6 hours. Antibiotic selection is applied after 24 hours and stable transgenic lines appear within 1 week. Our protocol is robust and reproducible for human iPSC lines without altering pluripotency of these cells.

Despite recent advancements in genetic modification, transfection of human embryonic stem cells (HESCs) remains a capricious process. To our knowledge, systematic and efficient methods to transfect human induced pluripotent stem cells (iPSCs) have not been reported. Here, we describe robust protocols to efficiently transfect and nucleofect human iPSCs.

Genetic modification is continuing to be an essential tool in studying stem cell biology and in setting forth potential clinical applications of human ...

Efficient Derivation of Human Cardiac Precursors and Cardiomyocytes from Pluripotent Human Embryonic Stem Cells with Small Molecule Induction

To date, the lack of a suitable human cardiac cell source has been the major setback in regenerating the human myocardium, either by cell-based transplantation or by cardiac tissue engineering1-3. Cardiomyocytes become terminally-differentiated soon after birth and lose their ability to proliferate. There is no evidence that stem/progenitor cells derived from other sources, such as the bone marrow or the cord blood, are able to give rise to the contractile heart muscle cells following transplantation into the heart1-3. The need to regenerate or repair the damaged heart muscle has not been met by adult stem cell therapy, either endogenous or via cell delivery1-3. The genetically stable human embryonic stem cells (hESCs) have unlimited expansion ability and unrestricted plasticity, proffering a pluripotent reservoir for in vitro derivation of large supplies of human somatic cells that are restricted to the lineage in need of repair and regeneration4,5. Due to the prevalence of cardiovascular disease worldwide and acute shortage of donor organs, there is intense interest in developing hESC-based therapies as an alternative approach. However, how to channel the wide differentiation potential of pluripotent hESCs efficiently and predictably to a desired phenotype has been a major challenge for both developmental study and clinical translation. Conventional approaches rely on multi-lineage inclination of pluripotent cells through spontaneous germ layer differentiation, resulting in inefficient and uncontrollable lineage-commitment that is often followed by phenotypic heterogeneity and instability, hence, a high risk of tumorigenicity6-8 (see a schematic in Fig. 1A). In addition, undefined foreign/animal biological supplements and/or feeders that have typically been used for the isolation, expansion, and differentiation of hESCs may make direct use of such cell-specialized grafts in patients problematic9-11. To overcome these obstacles, we have resolved the elements of a defined culture system necessary and sufficient for sustaining the epiblast pluripotence of hESCs, serving as a platform for de novo derivation of clinically-suitable hESCs and effectively directing such hESCs uniformly towards clinically-relevant lineages by small molecules12 (see a schematic in Fig. 1B). After screening a variety of small molecules and growth factors, we found that such defined conditions rendered nicotinamide (NAM) sufficient to induce the specification of cardiomesoderm direct from pluripotent hESCs that further progressed to cardioblasts that generated human beating cardiomyocytes with high efficiency (Fig. 2). We defined conditions for induction of cardioblasts direct from pluripotent hESCs without an intervening multi-lineage embryoid body stage, enabling well-controlled efficient derivation of a large supply of human cardiac cells across the spectrum of developmental stages for cell-based therapeutics.

We have established a protocol for induction of cardioblasts direct from pluripotent human embryonic stem cells maintained under defined conditions with small molecules, which enables derivation of a large supply of human cardiac progenitors and functional cardiomyocytes for cardiovascular repair.

To date, the lack of a suitable human cardiac cell source has been the major setback in regenerating the human myocardium, either by cell-based ...

Reprogramming Human Somatic Cells into Induced Pluripotent Stem Cells (iPSCs) Using Retroviral Vector with GFP

Human embryonic stem cells (hESCs) are pluripotent and an invaluable cellular sources for in vitro disease modeling and regenerative medicine1. It has been previously shown that human somatic cells can be reprogrammed to pluripotency by ectopic expression of four transcription factors (Oct4, Sox2, Klf4 and Myc) and become induced pluripotent stem cells (iPSCs)2-4 . Like hESCs, human iPSCs are pluripotent and a potential source for autologous cells. Here we describe the protocol to reprogram human fibroblast cells with the four reprogramming factors cloned into GFP-containing retroviral backbone4. Using the following protocol, we generate human iPSCs in 3-4 weeks under human ESC culture condition. Human iPSC colonies closely resemble hESCs in morphology and display the loss of GFP fluorescence as a result of retroviral transgene silencing. iPSC colonies isolated mechanically under a fluorescence microscope behave in a similar fashion as hESCs. In these cells, we detect the expression of multiple pluripotency genes and surface markers.

Reprogramming Human Somatic Cells into Induced Pluripotent Stem Cells iPSCs Using Retroviral Vector with GFP

A method to generate human induced pluripotent stem cells (iPSCs) via retrovirus-mediated ectopic expression of OCT4, SOX2, KLF4 and MYC is described. A practical way to identify human iPSC colonies based on GFP expression is also discussed.

Human embryonic stem cells (hESCs) are pluripotent and an invaluable cellular sources for in vitro disease modeling and regenerative medicine1. It has ...

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 ...

Generation of Human Induced Pluripotent Stem Cells from Peripheral Blood Using the STEMCCA Lentiviral Vector

Through the ectopic expression of four transcription factors, Oct4, Klf4, Sox2 and cMyc, human somatic cells can be converted to a pluripotent state, generating so-called induced pluripotent stem cells (iPSCs)1-4. Patient-specific iPSCs lack the ethical concerns that surround embryonic stem cells (ESCs) and would bypass possible immune rejection. Thus, iPSCs have attracted considerable attention for disease modeling studies, the screening of pharmacological compounds, and regenerative therapies5.
We have shown the generation of transgene-free human iPSCs from patients with different lung diseases using a single excisable polycistronic lentiviral Stem Cell Cassette (STEMCCA) encoding the Yamanaka factors6. These iPSC lines were generated from skin fibroblasts, the most common cell type used for reprogramming. Normally, obtaining fibroblasts requires a skin punch biopsy followed by expansion of the cells in culture for a few passages. Importantly, a number of groups have reported the reprogramming of human peripheral blood cells into iPSCs7-9. In one study, a Tet inducible version of the STEMCCA vector was employed9, which required the blood cells to be simultaneously infected with a constitutively active lentivirus encoding the reverse tetracycline transactivator. In contrast to fibroblasts, peripheral blood cells can be collected via minimally invasive procedures, greatly reducing the discomfort and distress of the patient. A simple and effective protocol for reprogramming blood cells using a constitutive single excisable vector may accelerate the application of iPSC technology by making it accessible to a broader research community. Furthermore, reprogramming of peripheral blood cells allows for the generation of iPSCs from individuals in which skin biopsies should be avoided (i.e. aberrant scarring) or due to pre-existing disease conditions preventing access to punch biopsies.
Here we demonstrate a protocol for the generation of human iPSCs from peripheral blood mononuclear cells (PBMCs) using a single floxed-excisable lentiviral vector constitutively expressing the 4 factors. Freshly collected or thawed PBMCs are expanded for 9 days as described10,11 in medium containing ascorbic acid, SCF, IGF-1, IL-3 and EPO before being transduced with the STEMCCA lentivirus. Cells are then plated onto MEFs and ESC-like colonies can be visualized two weeks after infection. Finally, selected clones are expanded and tested for the expression of the pluripotency markers SSEA-4, Tra-1-60 and Tra-1-81. This protocol is simple, robust and highly consistent, providing a reliable methodology for the generation of human iPSCs from readily accessible 4 ml of blood.

Here we show a simple and effective protocol for the generation of human iPSCs from 3-4 ml of peripheral blood using a single lentiviral reprogramming vector. Reprogramming of readily available blood cells promises to accelerate the utilization of iPSC technology by making it accessible to a broader research community.

Through the ectopic expression of four transcription factors, Oct4, Klf4, Sox2 and cMyc, human somatic cells can be converted to a pluripotent state, ...

Generation of Human Cardiomyocytes: A Differentiation Protocol from Feeder-free Human Induced Pluripotent Stem Cells

In order to investigate the events driving heart development and to determine the molecular mechanisms leading to myocardial diseases in humans, it is essential first to generate functional human cardiomyocytes (CMs). The use of these cells in drug discovery and toxicology studies would also be highly beneficial, allowing new pharmacological molecules for the treatment of cardiac disorders to be validated pre-clinically on cells of human origin. Of the possible sources of CMs, induced pluripotent stem (iPS) cells are among the most promising, as they can be derived directly from readily accessible patient tissue and possess an intrinsic capacity to give rise to all cell types of the body 1. Several methods have been proposed for differentiating iPS cells into CMs, ranging from the classical embryoid bodies (EBs) aggregation approach to chemically defined protocols 2,3. In this article we propose an EBs-based protocol and show how this method can be employed to efficiently generate functional CM-like cells from feeder-free iPS cells.

Pluripotent stem cells, either embryonic or induced pluripotent stem (iPS) cells, constitute a valuable source of human differentiated cells, including cardiomyocytes. Here, we will focus on cardiac induction of iPS cells, showing how to use them to obtain functional human cardiomyocytes through an embryoid bodies-based protocol.

In order to investigate the events driving heart development and to determine the molecular mechanisms leading to myocardial diseases in humans, it is ...

Rapid and Efficient Zebrafish Genotyping Using PCR with High-resolution Melt Analysis

Zebrafish is a powerful vertebrate model system for studying development, modeling disease, and performing drug screening. Recently a variety of genetic tools have been introduced, including multiple strategies for inducing mutations and generating transgenic lines. However, large-scale screening is limited by traditional genotyping methods, which are time-consuming and labor-intensive. Here we describe a technique to analyze zebrafish genotypes by PCR combined with high-resolution melting analysis (HRMA).&#160;This approach is rapid, sensitive, and inexpensive, with lower risk of contamination artifacts.&#160;Genotyping by PCR with HRMA can be used for embryos or adult fish, including in high-throughput screening protocols.

PCR combined with high-resolution melt analysis (HRMA) is demonstrated as a rapid and efficient method to genotype zebrafish.

Zebrafish is a powerful vertebrate model system for studying development, modeling disease, and performing drug screening. Recently a variety of genetic ...

Efficient Generation Human Induced Pluripotent Stem Cells from Human Somatic Cells with Sendai-virus

A few years ago, the establishment of human induced pluripotent stem cells (iPSCs) ushered in a new era in biomedicine. Potential uses of human iPSCs include modeling pathogenesis of human genetic diseases, autologous cell therapy after gene correction, and personalized drug screening by providing a source of patient-specific and symptom relevant cells. However, there are several hurdles to overcome, such as eliminating the remaining reprogramming factor transgene expression after human iPSCs production. More importantly, residual transgene expression in undifferentiated human iPSCs could hamper proper differentiations and misguide the interpretation of disease-relevant in vitro phenotypes. With this reason, integration-free and/or transgene-free human iPSCs have been developed using several methods, such as adenovirus, the piggyBac system, minicircle vector, episomal vectors, direct protein delivery and synthesized mRNA. However, efficiency of reprogramming using integration-free methods is quite low in most cases.
Here, we present a method to isolate human iPSCs by using Sendai-virus (RNA virus) based reprogramming system. This reprogramming method shows consistent results and high efficiency in cost-effective manner.

Here, we present our established method to reprogram human somatic cells into transgene-free human iPSCs with Sendai virus, which shows consistent outcome and enhanced efficiency.

A few years ago, the establishment of human induced pluripotent stem cells (iPSCs) ushered in a new era in biomedicine. Potential uses of human iPSCs ...

Efficient Sporulation of Saccharomyces cerevisiae in a 96 Multiwell Format

During times of nutritional stress, Saccharomyces cerevisiae undergoes gametogenesis, known as sporulation. Diploid yeast cells that are starved for nitrogen and carbon will initiate the sporulation process. The process of sporulation includes meiosis followed by spore formation, where the haploid nuclei are packaged into environmentally resistant spores. We have developed methods for the efficient sporulation of budding yeast in 96 multiwell plates, to increase the throughput of screening yeast cells for sporulation phenotypes. These methods are compatible with screening with yeast containing plasmids requiring nutritional selection, when appropriate minimal media is used, or with screening yeast with genomic alterations, when a rich presporulation regimen is used. We find that for this method, aeration during sporulation is critical for spore formation, and have devised techniques to ensure sufficient aeration that are compatible with the 96 multiwell plate format. Although these methods do not achieve the typical ~80% level of sporulation that can be achieved in large-volume flask based experiments, these methods will reliably achieve about 50-60% level of sporulation in small-volume multiwell plates.

Efficient Sporulation of Saccharomyces cerevisiae in a 96 Multiwell Format

Here, sporulation of Saccharomyces cerevisiae is carried out in a 96 multiwell format.

During times of nutritional stress, Saccharomyces cerevisiae undergoes gametogenesis, known as sporulation. Diploid yeast cells that are starved for ...

Efficient and Consistent Generation of Retinal Pigment Epithelium/Choroid Flatmounts from Human Eyes for Histological Analysis

The retinal pigment epithelium (RPE) and retina are functionally and structurally connected tissues that work together to regulate light perception and vision. Proteins on the RPE apical surface are tightly associated with proteins on the photoreceptor outer segment surface, making it difficult to consistently separate the RPE from the photoreceptors/retina. We developed a method to efficiently separate the retina from the RPE of human eyes to generate complete RPE/choroid and retina flatmounts for separate cellular analysis of the photoreceptors and RPE cells. An intravitreal injection of a high-osmolarity solution of D-mannitol, a sugar not transported by the RPE, induced the separation of the RPE and retina across the entire posterior chamber without causing damage to the RPE cell junctions. No RPE patches were observed attached to the retina. Phalloidin labeling of actin showed RPE shape preservation and allowed morphometric analysis of the entire epithelium. An artificial intelligence (AI)-based software was developed to accurately recognize and segment the RPE cell borders and quantify 30 different shape metrics. This dissection method is highly reproducible and can be easily extended to other animal models.

We describe a method to efficiently separate retinal pigment epithelium (RPE) from the retina in human eyes and generate whole RPE/choroid flatmounts for histological and morphometric analyses of the RPE.

The retinal pigment epithelium (RPE) and retina are functionally and structurally connected tissues that work together to regulate light perception and ...