This work was supported by a fellowship for melanoma researchers from the Joanna M. Nicolay Foundation and by the National Institutes of Health under Ruth L. Kirschstein National Research Service Award F31. This work was further supported through grants from NYSTEM and the Tri-institutional stem cell initiative (Starr Foundation).

NOTE: The melanocyte protocol outlined here was first demonstrated by Mica et al.
1. Preparation of Culture Medium, Coated Dishes and Maintenance of hPSCs
<ol>
	<li>Medium Preparation 
	Note: Store all medium at 4 &#176;C in the dark for up to 2 weeks. Filter all medium for sterilization.
	<ol>
		<li>Prepare DMEM/10% FBS. Mix 885 ml DMEM, 100 ml FBS, 10 ml Pen/Strep and 5 ml L-Glutamine. Filter for sterilization.</li>
		<li>Prepare hESC-medium. Mix 800 ml DMEM/F12, 200 ml KSR, 5 ml L-Glutamine, 10 ml MEM minimum essential amino acids solution, 1 ml &#946;-Mercaptoethanol, and 5 ml Pen/Strep. After filtering add 10 ng/ml FGF-2.</li>
		<li>Prepare KSR-differentiation medium: Mix 820 ml Knockout DMEM, 150 ml KSR, 10 ml L-Glutamine, 10 ml Pen/Strep, 10 ml MEM minimum essential amino acids solution and 1 ml &#946;-Mercaptoethanol. Filter for sterilization.</li>
		<li>Prepare N2-differentiation medium. Dissolve 12 g DMEM/F12 powder in 980 ml dH2O. Add 1.55 g glucose, 2 g sodium bicarbonate and 100 mg apo human transferrin. Mix 2 ml dH2O with 25 mg human insulin and 40 &#181;l 1 N NaOH; once dissolved, add the mixture to the medium. Add 100 &#181;l putrescine dihydrochloride, 60 &#181;l selenite, 100 &#181;l progesterone. Bring the final volume to 1 l with dH2O before filtering.</li>
		<li>Prepare Full melanocyte medium. Combine 50% Neurobasal medium, 30% Low glucose DMEM, and 20% MCDB201. To this add: 0.8% ITS+, 250 nM L-glutamine, 100 &#181;M Ascorbic Acid (L-AA), 50 ng/ml Cholera toxin, 50 ng/ml SCF, 0.05 &#181;M Dexamethasone, 100 nM EDN3, 4 ng/ml FGF2. Sterile filter then add remaining reagents: 2% B27 Supplement, 25 ng/ml BMP4, 3 &#181;M CHIR99021, 500 &#181;M cAMP.</li>
	</ol>
	</li>
	<li>Coating of Culture Dishes
	<ol>
		<li>Carry out coating using gelatinous protein such as Matrigel. Upon opening, aliquot and freeze Matrigel into 1 ml parts to avoid repetitive freeze thaw cycles. Thaw and re-suspend a 1 ml frozen aliquot with 19 ml DMEM/F12. Plate 5 ml onto a 10 cm dish. Incubate the dishes for 1 hr at RT. Aspirate the gelatinous protein immediately before plating the cells and wash with DMEM/F12.</li>
		<li>Carry out coating using Poly-L ornithin hydrobromide/ mouse Laminin-I/ fibronectin (PO/Lam/FN). Coat dish with PBS containing 15 &#181;g/ml Poly-L ornithin hydrobromide. Incubate O/N at 37 &#176;C in a humidified incubator. Aspirate the solution and wash the plates with PBS three times before coating with PBS containing 1 &#181;g/ml mouse Laminin-I and 2 &#181;g/ml fibronectin. Incubate the dishes O/N at 37 &#176;C in a humidified incubator.
		<ol>
			<li>Prior to plating cells, aspirate the solution and let the plates dry thoroughly without the lid in the tissue culture hood. Allow the plates to dry for approximately 10-15 min. 
			Note: The dishes are dry and ready for cell plating when crystal structures appear on the surface by eye. The plates can be kept with PBS containing LAM/FN in the incubator for two weeks, as long as the liquid does not evaporate. The plates can be kept dried at RT for a few hr.&#160;</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Maintenance of hPSCs 
	Note: hPSCs are maintained on 0.1% gelatin and mitotically inactivated mouse embryonic fibroblasts (MEFs) in hESC-medium. The cells should be split every 6-8 days.
	<ol>
		<li>Coat a 10 cm dish with 0.1% gelatin in PBS at RT for 5 min.</li>
		<li>Thaw frozen MEFs quickly in a 37 &#176;C water bath.</li>
		<li>Aspirate the gelatin and plate the cells. Plate MEFs at a density of ~50,000 cells/cm2 in DMEM/10% FBS. Incubate MEFs at 37 &#176;C O/N prior to adding hPSCs.</li>
		<li>Aspirate the DMEM/10% FBS from the prepared MEF plate, wash plate with PBS and add 10 ml hESC-medium with hPSCs. Passage the hPSCs at a ratio of 1:5/10 depending on density prior to passaging. 
		Note: If the hPSCs are being thawed or passaged as single cells, supplement with 10 &#181;M Y-27632 dihydrochloride (ROCKi) until the first passage.</li>
		<li>Feed cells daily with fresh 10 ml hESC-medium.</li>
		<li>Prior to starting a differentiation remove any pluripotent colonies that appear to contain differentiated cells, irregular borders, or transparent centers 28. Mechanically dislodge and aspirate the irregular colonies with a pipette under a laminar flow hood with a dissecting microscope.</li>
	</ol>
	</li>
</ol>
2. Plating of hPSCs for Differentiation
Note: Differentiation conditions are described for 10 cm dishes.
<ol>
	<li>Prepare 10 cm Matrigel dishes before starting the differentiation as described in Step 1.3.1.</li>
	<li>When plating hPSCs for a differentiation start with a plate of hPSCs at a density ready for passage (~80% confluent) aspirate the hESC-medium, wash with PBS and add 3 ml of 0.05% trypsin-EDTA to the cells.</li>
	<li>Vigorously shake the dish horizontally for 2 min while visualizing under the microscope until the MEFs lift off as single cells. The hPSC colonies should remain attached as colonies.</li>
	<li>Aspirate the trypsin after the MEFs have lifted but before the hPSCs colonies detach.</li>
	<li>Add 10 ml of hESC-medium containing 10 &#181;M Y-27632 dihydrochloride to the plate and detach the cells by pipetting up and down over the colonies.</li>
	<li>Aspirate the Matrigel solution from the 10 cm dish prepared in step 2.1 and wash with DMEM/F12 to remove clumps. Plate the hPSCs at a 1:2 ratio onto the Matrigel plate. Add hESC-medium containing 10 &#181;M Y-27632 dihydrochloride up to 10ml. Incubate at 37 &#176;C O/N. 
	Note: This plating should result in approximately 100,000 cells/cm2.</li>
</ol>
3. Induction of Neural Differentiation
Note: The differentiation should be initiated (day 0) when the hPSCs are 80% confluent. The cells can be fed daily with hESC-medium containing 10 &#181;M Y-27632 dihydrochloride until beginning the differentiation.
<ol>
	<li>On day 0 and day 1, feed the cells with 10 ml of KSR-differentiation medium containing 100 nM LDN193189 and 10 &#181;M SB431542.</li>
	<li>On day 2, feed the cells with 10 ml of KSR-differentiation medium containing 100 nM LDN193189, 10 &#181;M SB431542 and 3 &#181;M CHIR99021.</li>
	<li>On day 3, feed the cells with 10 ml of KSR-differentiation medium containing 10 &#181;M SB431542 and 3 &#181;M CHIR99021.</li>
	<li>On days 4 and 5 feed the cells with 15 ml of 75% KSR-differentiation medium and 25% N2-differentiation medium containing 3 &#181;M CHIR99021. 
	Note: Do not be alarmed to see a large amount of cell death in terms of floating cells. This is normal and to be expected.</li>
	<li>On days 6 and 7 feed the cells with 15 ml of 50% KSR-differentiation medium and 50% N2-differentiation medium both containing 3 &#181;M CHIR99021, 25 ng/ml BMP4, and 100 nM EDN3.</li>
	<li>On days 8 and 9 feed the cells with 20 ml of 25% KSR-differentiation medium and 75% N2-differentiation medium both containing 3 &#181;M CHIR99021, 25 ng/ml BMP4, and 100 nM EDN3.</li>
	<li>On days 9 and 10 prepare PO/Lam/FN dishes as indicated in 1.2.2 for re-plating of the cells on day 11.</li>
	<li>On day 10 feed cells with 20 ml of N2-differentiation medium containing 3 &#181;M CHIR99021, 25 ng/ml BMP4, and 100 nM EDN3.</li>
</ol>
4. Replating in Droplets for NC Specification
<ol>
	<li>On day 11 aspirate Lam/FN from the prepared PO/LAM/FN plates and dry completely.</li>
	<li>Remove medium from the Day 11 cells, wash with PBS and add 4 ml cell detachment solution such as Accutase per 10 cm dish. Incubate for 25 min at 37 &#176;C.</li>
	<li>Add 5 ml of Full Melanocyte medium to the dish and resuspend the cells by manually pipetting up and down with a 10 ml pipette until all the cells have lifted off the plate. Transfer the suspension to a 15 ml tube.</li>
	<li>Spin the cells down for 5 min at 200 x g and resuspend the cells at 2 x 106 cells per ml in Full Melanocyte medium. Count the cells using the trypan blue exclusion on a hemocytometer or equivalent technique.</li>
	<li>Plate 10 &#181;l droplets close to each other (without them touching) onto the dried PO/Lam/FN 10 cm dishes. If the plate has been sufficiently dried, the droplets should have well defined edges and not run. 
	Note: This creates a high density local environment for the cells, which is important when replating the cells, while maintaining room within the dish for expansion.</li>
	<li>Allow the droplets to stand at RT for 10-20 min to allow cells to adhere, then slowly (not to disturb the attached cells) add 10 ml of Full Melanocyte medium. Move dish to the incubator.</li>
</ol>
5. Expanding Melanocyte Progenitors
<ol>
	<li>Continue feeding with Full Melanocyte medium every 2 to 3 days. 
	Note: Pigmentation should start to be visible within clusters of cells by the end of the first week and become very clear by the second week. View the plate over a white background such as a sheet of paper to discern these early small, dark clusters. Cells will become progressively more pigmented over time, until the entire plate is uniformly pigmented (See Figure 2B).</li>
	<li>Passage cells once a week at a ratio of ~1:6 (plating as droplets is no longer necessary at this stage). Use Accutase to dissociate cells and wash twice with plain Neurobasal medium before re-plating in Full Melanocyte medium. Maintain cells on PO/LAM/FN plates. 
	Note: We have found that the Full Melanocyte medium is best suited for maintaining and expanding hESC and iPSC-derived melanocytes. However, cells can be briefly cultured in commercially available M254 medium but the simplified media increases the risk of cells dying and lifting off the plate.</li>
</ol>

<ol>
	<li>Ebert, A. D., 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=Induced+pluripotent+stem+cells+from+a+spinal+muscular+atrophy+patient.">Induced pluripotent stem cells from a spinal muscular atrophy patient.</a> Nature. 457, 277-280 (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=Modelling+pathogenesis+and+treatment+of+familial+dysautonomia+using+patient-specific+iPSCs.">Modelling pathogenesis and treatment of familial dysautonomia using patient-specific iPSCs.</a> Nature. 461, 402-406 (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=Large-scale+screening+using+familial+dysautonomia+induced+pluripotent+stem+cells+identifies+compounds+that+rescue+IKBKAP+expression.">Large-scale screening using familial dysautonomia induced pluripotent stem cells identifies compounds that rescue IKBKAP expression.</a> Nat biotechnol. 30, 1244-1248 (2012).</li><li>Lee, G., Studer, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induced+pluripotent+stem+cell+technology+for+the+study+of+human+disease.">Induced pluripotent stem cell technology for the study of human disease.</a> Nat methods. 7, 25-27 (2010).</li><li>Zimmer, B., 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=Evaluation+of+developmental+toxicants+and+signaling+pathways+in+a+functional+test+based+on+the+migration+of+human+neural+crest+cells.">Evaluation of developmental toxicants and signaling pathways in a functional test based on the migration of human neural crest cells.</a> Environ health persp. 120, 1116-1122 (2012).</li><li>Mica, Y., Lee, G., Chambers, S. M., Tomishima, M. J., Studer, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+neural+crest+induction,+melanocyte+specification,+and+disease-related+pigmentation+defects+in+hESCs+and+patient-specific+iPSCs.">Modeling neural crest induction, melanocyte specification, and disease-related pigmentation defects in hESCs and patient-specific iPSCs.</a> Cell rep. 3, 1140-1152 (2013).</li><li>Mariani, 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=FOXG1-Dependent+Dysregulation+of+GABA/Glutamate+Neuron+Differentiation+in+Autism+Spectrum+Disorders.">FOXG1-Dependent Dysregulation of GABA/Glutamate Neuron Differentiation in Autism Spectrum Disorders.</a> Cell. 162, 375-390 (2015).</li><li>Doulatov, S., 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=Modeling+Diamond+Blackfan+Anemia+in+Vivo+Using+Human+Induced+Pluripotent+Stem+Cells.">Modeling Diamond Blackfan Anemia in Vivo Using Human Induced Pluripotent Stem Cells.</a> Blood. 124, (2014).</li><li>Cherry, A. B. C., Daley, G. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reprogrammed+Cells+for+Disease+Modeling+and+Regenerative+Medicine.">Reprogrammed Cells for Disease Modeling and Regenerative Medicine.</a> Annu Rev Med. 64, 277-290 (2013).</li><li>Inoue, H., Nagata, N., Kurokawa, H., Yamanaka, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=iPS+cells:+a+game+changer+for+future+medicine.">iPS cells: a game changer for future medicine.</a> Embo J. 33, 409-417 (2014).</li><li>Kim, C., 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=Studying+arrhythmogenic+right+ventricular+dysplasia+with+patient-specific+iPSCs.">Studying arrhythmogenic right ventricular dysplasia with patient-specific iPSCs.</a> Nature. 494, 105-110 (2013).</li><li>Fang, D., 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=Defining+the+conditions+for+the+generation+of+melanocytes+from+human+embryonic+stem+cells.">Defining the conditions for the generation of melanocytes from human embryonic stem cells.</a> Stem cells. 24, 1668-1677 (2006).</li><li>Huang, X., Saint-Jeannet, 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=Induction+of+the+neural+crest+and+the+opportunities+of+life+on+the+edge.">Induction of the neural crest and the opportunities of life on the edge.</a> Dev biol. 275, 1-11 (2004).</li><li>White, R. M., Zon, L. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Melanocytes+in+development,+regeneration,+and+cancer.">Melanocytes in development, regeneration, and cancer.</a> Cell stem cell. 3, 242-252 (2008).</li><li>Morrison, S. J., White, P. M., Zock, C., Anderson, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prospective+identification,+isolation+by+flow+cytometry,+and+in+vivo+self-renewal+of+multipotent+mammalian+neural+crest+stem+cells.">Prospective identification, isolation by flow cytometry, and in vivo self-renewal of multipotent mammalian neural crest stem cells.</a> Cell. 96, 737-749 (1999).</li><li>Elworthy, S., Pinto, J. P., Pettifer, A., Cancela, M. L., Kelsh, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phox2b+function+in+the+enteric+nervous+system+is+conserved+in+zebrafish+and+is+sox10-dependent.">Phox2b function in the enteric nervous system is conserved in zebrafish and is sox10-dependent.</a> Mech develop. 122, 659-669 (2005).</li><li>Harris, M. L., Baxter, L. L., Loftus, S. K., Pavan, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sox+proteins+in+melanocyte+development+and+melanoma.">Sox proteins in melanocyte development and melanoma.</a> Pigm cell melanoma r. 23, 496-513 (2010).</li><li>Herbarth, B., 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=Mutation+of+the+Sry-related+Sox10+gene+in+Dominant+megacolon,+a+mouse+model+for+human+Hirschsprung+disease.">Mutation of the Sry-related Sox10 gene in Dominant megacolon, a mouse model for human Hirschsprung disease.</a> PNAS. 95, 5161-5165 (1998).</li><li>Southard-Smith, E. M., Kos, L., Pavan, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sox10+mutation+disrupts+neural+crest+development+in+Dom+Hirschsprung+mouse+model.">Sox10 mutation disrupts neural crest development in Dom Hirschsprung mouse model.</a> Nat genetics. 18, 60-64 (1998).</li><li>Dupin, E., Glavieux, C., Vaigot, P., Le Douarin, N. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelin+3+induces+the+reversion+of+melanocytes+to+glia+through+a+neural+crest-derived+glial-melanocytic+progenitor.">Endothelin 3 induces the reversion of melanocytes to glia through a neural crest-derived glial-melanocytic progenitor.</a> PNAS. 97, 7882-7887 (2000).</li><li>Lister, J. A., Robertson, C. P., Lepage, T., Johnson, S. L., Raible, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=nacre+encodes+a+zebrafish+microphthalmia-related+protein+that+regulates+neural-crest-derived+pigment+cell+fate.">nacre encodes a zebrafish microphthalmia-related protein that regulates neural-crest-derived pigment cell fate.</a> Development. 126, 3757-3767 (1999).</li><li>Hou, L., Panthier, J. J., Arnheiter, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Signaling+and+transcriptional+regulation+in+the+neural+crest-derived+melanocyte+lineage:+interactions+between+KIT+and+MITF.">Signaling and transcriptional regulation in the neural crest-derived melanocyte lineage: interactions between KIT and MITF.</a> Development. 127, 5379-5389 (2000).</li><li>Levy, C., Khaled, M., Fisher, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MITF:+master+regulator+of+melanocyte+development+and+melanoma+oncogene.">MITF: master regulator of melanocyte development and melanoma oncogene.</a> Trends mol med. 12, 406-414 (2006).</li><li>Phung, B., Sun, J., Schepsky, A., Steingrimsson, E., Ronnstrand, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=C-KIT+signaling+depends+on+microphthalmia-associated+transcription+factor+for+effects+on+cell+proliferation.">C-KIT signaling depends on microphthalmia-associated transcription factor for effects on cell proliferation.</a> PloS one. 6, e24064 (2011).</li><li>Grichnik, J. 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=KIT+expression+reveals+a+population+of+precursor+melanocytes+in+human+skin.">KIT expression reveals a population of precursor melanocytes in human skin.</a> J invest dermatol. 106, 967-971 (1996).</li><li>Li, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+dermal+stem+cells+differentiate+into+functional+epidermal+melanocytes.">Human dermal stem cells differentiate into functional epidermal melanocytes.</a> J cell sci. 123, 853-860 (2010).</li><li>Nishimura, E. K., 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=Dominant+role+of+the+niche+in+melanocyte+stem-cell+fate+determination.">Dominant role of the niche in melanocyte stem-cell fate determination.</a> Nature. 416, 854-860 (2002).</li><li>Zur Nieden, N. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Embryonic stem cell therapy for osteo-degenerative diseases : methods and protocols. , (2011).</li><li>Lee, J. H., 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=high-content+screening+for+novel+pigmentation+regulators+using+a+keratinocyte/melanocyte+co-culture+system.">high-content screening for novel pigmentation regulators using a keratinocyte/melanocyte co-culture system.</a> Exp dermatol. 23, 125-129 (2014).</li></ol>

The authors have no conflicting interests to disclose.

For the successful differentiation of melanocytes from hPSCs the following suggestions should be taken into consideration. First and foremost, it is essential to work under sterile culture conditions at all times. Additionally, it is important to start with pluripotent, fully undifferentiated hPSCs; if the starting population contains differentiated cells the yield will invariably drop as the contaminants cannot be directed towards melanocytes and may even further disrupt the properly differentiating cells.
<p class=...

Human pluripotent stem cells (hPSCs) provide a platform to mimic normal differentiation in a scalable fashion for disease modeling, drug screening, and cell replacement therapies 1-6. Of particular interest, hPSCs open up avenues for studying difficult to isolate or rare/transient cell types where patient samples are scarce. Furthermore, induced pluripotent stem cells (iPSCs) enable researchers to study development and disease modeling in a patient specific manner to unravel unique mechanisms 1,2,7-11. The previously published protocol for differentiation of melanocytes from hPSCs requires up to 6 weeks of differentiations and involves culturing cells with conditioned medium from L-Wnt3a cells 12. The protocol first presented by Mica et al. and described here produces pigmented cells in three weeks and removes the ambiguity and inconsistencies associated with conditioned medium.
Melanocytes are derived from the neural crest, a migratory population of cells unique to vertebrates. The neural crest is defined during gastrulation and represents a population of cells at the edge of the neural plate, bordering between the neural and non-neural ectoderm. During neurulation, the nervous tissue evolves from a neural plate to form neural folds, which converge at the dorsal midline resulting in the neural tube 13,14.
The neural crest cells emerge from the roof plate of the neural tube, opposite the notochord, and undergo an epithelial to mesenchymal transition before migrating away to give rise to a diverse population of differentiated cells. The fates of the crest cells are defined in part by the anatomic location of the roof plate along the body axis of the embryo. Neural crest cell derivatives include lineages characteristic of both mesoderm (smooth muscle cells, osteoblasts, adipocytes, chondrocytes) and ectoderm cells (melanocytes, Schwann cells, neurons) 14. Neural crest stem cells upregulate the transcription factor SOX10 and can be isolated by fluorescence-activated cell sorting with antibodies to p75 and HNK1.
The neural crest cells fated to become melanocytes pass through a melanoblast stage and upregulate KIT and MITF (microphthalmia-associated transcription factor) 6,21 MITF is a master regulator of melanocyte development and is a transcription factor responsible for controlling much of melanocyte development 22-24. Human melanoblasts migrate to the basal layer of the epidermis where they reside either in the hair bulge or surrounded by keratinocytes in the epidermis (forming pigmentation units) to serve as precursors to the mature, pigmented melanocytes. The differentiation and maturation of melanoblasts into pigmented melanocytes occurs concomitant with colonization of the hair bulb and expression of the melanin production pathway (TYRP1, TYR, OCA2 and PMEL) 25,26.
Isolating human melanocytes and melanoblasts from patients is expensive, difficult and limiting in quantity. This protocol enables researchers to differentiate hPSCs (induced or embryonic) into melanocytes or melanocyte precursors in a well defined, rapid, reproducible, scalable, and inexpensive method without cell sorting. The protocol was used previously to identify disease-specific defects when differentiating iPSCs from patients with pigmentation disorders .

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Accutase</td>
			<td>Innovative Cell Technologies</td>
			<td>AT104</td>
			<td></td>
		</tr>
		<tr>
			<td>apo human transferrin</td>
			<td>Sigma</td>
			<td>T1147</td>
			<td></td>
		</tr>
		<tr>
			<td>Ascorbic Acid (L-AA)</td>
			<td>Sigma</td>
			<td>A4034</td>
			<td>100 mM</td>
		</tr>
		<tr>
			<td>B27 (B27 Supplement)</td>
			<td>Invitrogen</td>
			<td>17504044</td>
			<td></td>
		</tr>
		<tr>
			<td>&#946;-Mercaptoethanol</td>
			<td>Gibco-Life Technologies</td>
			<td>21985-023</td>
			<td>10 mg/ml</td>
		</tr>
		<tr>
			<td>BMP4</td>
			<td>R&#38;D Systems</td>
			<td>314-bp</td>
			<td></td>
		</tr>
		<tr>
			<td>CHIR99021</td>
			<td>Tocris-R&#38;D Systems</td>
			<td>4423</td>
			<td>6 mM</td>
		</tr>
		<tr>
			<td>Cholera toxin</td>
			<td>Sigma</td>
			<td>C8052</td>
			<td>50 mg/ml</td>
		</tr>
		<tr>
			<td>cAMP (cyclicAMP)</td>
			<td>Sigma</td>
			<td>D0627</td>
			<td>100 mM</td>
		</tr>
		<tr>
			<td>Dexamethasone</td>
			<td>Sigma</td>
			<td>D2915-100MG</td>
			<td>50 &#956;M</td>
		</tr>
		<tr>
			<td>DMEM - Dulbecco&#39;s Modified Eagle Medium</td>
			<td>Gibco-Life Technologies</td>
			<td>11985-092</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM/F12 - Dulbecco&#39;s Modified Eagle Medium: Nutrient Mixture F-12</td>
			<td>Gibco-Life Technologies</td>
			<td>1133--032</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM/F12 powder</td>
			<td>Invitrogen</td>
			<td>12500-096</td>
			<td></td>
		</tr>
		<tr>
			<td>EDN3 (Endothelin-3, human)</td>
			<td>American Peptide Company</td>
			<td>88-5-10B</td>
			<td>100 &#956;M</td>
		</tr>
		<tr>
			<td>Fibronectin</td>
			<td>BD Biosciences</td>
			<td>356008</td>
			<td>200 &#956;g/ml</td>
		</tr>
		<tr>
			<td>gelatin (PBS without Mg/Ca)</td>
			<td>in house</td>
			<td></td>
			<td>0.1% in PBS</td>
		</tr>
		<tr>
			<td>Glucose</td>
			<td>Sigma</td>
			<td>G7021</td>
			<td></td>
		</tr>
		<tr>
			<td>Human insulin</td>
			<td>Sigma</td>
			<td>I2643</td>
			<td></td>
		</tr>
		<tr>
			<td>ITS+ Universal Culture Supplement Premix&#160;</td>
			<td>BD Biosciences</td>
			<td>354352</td>
			<td></td>
		</tr>
		<tr>
			<td>KSR (Knockout Serum Replacement)</td>
			<td>Gibco-Life Technologies</td>
			<td>10828-028</td>
			<td></td>
		</tr>
		<tr>
			<td>Knockout DMEM</td>
			<td>Gibco-Life Technologies</td>
			<td>10829-018</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Glutamine</td>
			<td>Gibco-Life Technologies</td>
			<td>25030-081</td>
			<td></td>
		</tr>
		<tr>
			<td>LDN193189</td>
			<td>Stemgent</td>
			<td>04-0074</td>
			<td>100 mM</td>
		</tr>
		<tr>
			<td>Low glucose DMEM</td>
			<td>Invitrogen</td>
			<td>11885-084</td>
			<td></td>
		</tr>
		<tr>
			<td>Matrigel matrix</td>
			<td>BD Biosciences</td>
			<td>354234</td>
			<td>Dissolve 1:20 in DMEM/F12</td>
		</tr>
		<tr>
			<td>MCDB201 Medium</td>
			<td>Sigma</td>
			<td>M6770</td>
			<td></td>
		</tr>
		<tr>
			<td>MEM minimum essential amino acids solution</td>
			<td>Gibco-Life Technologies</td>
			<td>11140-080</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse embryonic fibroblasts (7 million cells/vial)</td>
			<td>GlobalStem</td>
			<td>GSC-8105M</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse Laminin-I</td>
			<td>R&#38;D Systems</td>
			<td>3400-010-01</td>
			<td>1 mg/ml</td>
		</tr>
		<tr>
			<td>Neurobasal medium</td>
			<td>Invitrogen</td>
			<td>21103049</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicilin/Streptomycin</td>
			<td>Gibco-Life Technologies</td>
			<td>15140-122</td>
			<td>10,000 U/ml</td>
		</tr>
		<tr>
			<td>Poly-L Omithin hydrobromide</td>
			<td>Sigma</td>
			<td>P3655</td>
			<td>15 mg/ml&#160;</td>
		</tr>
		<tr>
			<td>Progesterone</td>
			<td>Sigma</td>
			<td>P8783</td>
			<td>0.032g in 100ml 100% ethanol</td>
		</tr>
		<tr>
			<td>Putrescine dihydrochloride</td>
			<td>Sigma</td>
			<td>P5780</td>
			<td></td>
		</tr>
		<tr>
			<td>FGF2 (Recombinant human FGF basic)</td>
			<td>R&#38;D Systems</td>
			<td>233-FB-001MG/CF</td>
			<td>10 mg/ml</td>
		</tr>
		<tr>
			<td>SB431542</td>
			<td>Tocris-R&#38;D Systems</td>
			<td>1814</td>
			<td>10 mM</td>
		</tr>
		<tr>
			<td>Selenite</td>
			<td>Sigma</td>
			<td>S5261</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Bicarbonate</td>
			<td>Sigma</td>
			<td>S5761</td>
			<td></td>
		</tr>
		<tr>
			<td>SCF (Stem Cell Factor, recombinant Human)&#160;</td>
			<td>Peprotech Inc.</td>
			<td>300-07</td>
			<td>50 &#956;g/ml</td>
		</tr>
		<tr>
			<td>TYRP1 (G-17) Antibody</td>
			<td>Santa Cruz</td>
			<td>10443</td>
			<td>1:200</td>
		</tr>
		<tr>
			<td>TYRP2 Antibody</td>
			<td>Abcam</td>
			<td>74073</td>
			<td>1:200</td>
		</tr>
		<tr>
			<td>Trypsin-EDTA (0.05%)</td>
			<td>Gibco-Life Technologies</td>
			<td>25300-054</td>
			<td></td>
		</tr>
		<tr>
			<td>Y-27632 dihydrochloride</td>
			<td>Tocris-R&#38;D Systems</td>
			<td>1254</td>
			<td>10 mM</td>
		</tr>
	</tbody>
</table>

feeder-free derivation of melanocytes from human pluripotent stem cells

Human pluripotent stem cells (hPSCs) represent a platform to study human development in vitro under both normal and disease conditions. Researchers can direct the differentiation of hPSCs into the cell type of interest by manipulating the culture conditions to recapitulate signals seen during development. One such cell type is the melanocyte, a pigment-producing cell of neural crest (NC) origin responsible for protecting the skin against UV irradiation. This protocol presents an extension of a currently available in vitro Neural Crest differentiation protocol from hPSCs to further differentiate NC into fully pigmented melanocytes. Melanocyte precursors can be enriched from the Neural Crest protocol via a timed exposure to activators of WNT, BMP, and EDN3 signaling under dual-SMAD-inhibition conditions. The resultant melanocyte precursors are then purified and matured into fully pigmented melanocytes by culture in a selective medium. The resultant melanocytes are fully pigmented and stain appropriately for proteins characteristic of mature melanocytes.

This protocol provides a method for deriving fully pigmented, mature melanocytes from hPSCs in an in vitro feeder-free, cost efficient, and reproducible manner. In contrast to the previously established Fang et al. protocol for hPSC-derived melanocytes, the outlined protocol does not require conditioned medium and decreases the time requirement. The Fang et al. protocol utilized conditioned medium from a WNT3A-producing murine cell line and took up to 6 weeks to...

Watch this Scientific Journal Video about Feeder-free Derivation of Melanocytes from Human Pluripotent Stem Cells at JoVE.com

Feeder-free Derivation of Melanocytes from Human Pluripotent Stem Cells

This work describes an in vitro differentiation protocol to produce pigmented, mature melanocytes from human pluripotent stem cells via a neural crest and melanoblast intermediate stage using a feeder-free, 25 day protocol.

Human pluripotent stem cells (hPSCs) represent a platform to study human development in vitro under both normal and disease conditions. Researchers can ...

feeder-free-derivation-melanocytes-from-human-pluripotent-stem

Research

JoVE Journal

Developmental Biology

10.2K Views.  Memorial Sloan-Kettering Cancer Center. This work describes an in vitro differentiation protocol to produce pigmented, mature melanocytes from human pluripotent stem cells via a neural crest and melanoblast intermediate stage using a feeder-free, 25 day protocol.

Video: Feeder-free Derivation of Melanocytes from Human Pluripotent Stem Cells

Derivation of Cardiac Progenitor Cells from Embryonic Stem Cells

Cardiac progenitor cells (CPCs) have the capacity to differentiate into cardiomyocytes, smooth muscle cells (SMC), and endothelial cells and hold great promise in cell therapy against heart disease. Among various methods to isolate CPCs, differentiation of embryonic stem cell (ESC) into CPCs attracts great attention in the field since ESCs can provide unlimited cell source. As a result, numerous strategies have been developed to derive CPCs from ESCs. In this protocol, differentiation and purification of embryonic CPCs from both mouse and human ESCs is described. Due to the difficulty of using cell surface markers to isolate embryonic CPCs, ESCs are engineered with fluorescent reporters activated by CPC-specific cre recombinase expression. Thus, CPCs can be enriched by fluorescence-activated cell sorting (FACS). This protocol illustrates procedures to form embryoid bodies (EBs) from ESCs for CPC specification and enrichment. The isolated CPCs can be subsequently cultured for cardiac lineage differentiation and other biological assays. This protocol is optimized for robust and efficient derivation of CPCs from both mouse and human ESCs.

In this protocol, derivation of cardiac progenitor cells from both mouse and human embryonic stem cells will be illustrated. A major strategy in this protocol is to enrich cardiac progenitor cells with flow cytometry using fluorescent reporters engineered into the embryonic stem cell lines.

Cardiac progenitor cells (CPCs) have the capacity to differentiate into cardiomyocytes, smooth muscle cells (SMC), and endothelial cells and hold great ...

Efficient Derivation of Retinal Pigment Epithelium Cells from Stem Cells

No cure has been discovered for age-related macular degeneration (AMD), the leading cause of vision loss in people over the age of 55. AMD is complex multifactorial disease with an unknown etiology, although it is largely thought to occur due to death or dysfunction of the retinal pigment epithelium (RPE), a monolayer of cells that underlies the retina and provides critical support for photoreceptors. RPE cell replacement strategies may hold great promise for providing therapeutic relief for a large subset of AMD patients, and RPE cells that strongly resemble primary human cells (hRPE) have been generated in multiple independent labs, including our own. In addition, the uses for iPS-RPE are not limited to cell-based therapies, but also have been used to model RPE diseases. These types of studies may not only elucidate the molecular bases of the diseases, but also serve as invaluable tools for developing and testing novel drugs. We present here an optimized protocol for directed differentiation of RPE from stem cells. Adding nicotinamide and either Activin A or IDE-1, a small molecule that mimics its effects, at specific time points, greatly enhances the yield of RPE cells. Using this technique we can derive large numbers of low passage RPE in as early as three months.

Stem cell-derived retinal pigment epithelium (RPE) cells may be used for multiple applications including cell-based therapies for retinal degeneration, disease modeling, and drug studies. Here we present a simple protocol for reproducibly deriving RPE from stem cells.

No cure has been discovered for age-related macular degeneration  (AMD), the leading cause of vision loss in people over the age of 55. AMD is complex ...

Derivation of Highly Purified Cardiomyocytes from Human Induced Pluripotent Stem Cells Using Small Molecule-modulated Differentiation and Subsequent Glucose Starvation

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have become an important cell source to address the lack of primary cardiomyocytes available for basic research and translational applications. To differentiate hiPSCs into cardiomyocytes, various protocols including embryoid body (EB)-based differentiation and growth factor induction have been developed. However, these protocols are inefficient and highly variable in their ability to generate purified cardiomyocytes. Recently, a small molecule-based protocol utilizing modulation of Wnt/&#946;-Catenin signaling was shown to promote cardiac differentiation with high efficiency. With this protocol, greater than 50%-60% of differentiated cells were cardiac troponin-positive cardiomyocytes were consistently observed. To further increase cardiomyocyte purity, the differentiated cells were subjected to glucose starvation to specifically eliminate non-cardiomyocytes based on the metabolic differences between cardiomyocytes and non-cardiomyocytes. Using this selection strategy, we consistently obtained a greater than 30% increase in the ratio of cardiomyocytes to non-cardiomyocytes in a population of differentiated cells. These highly purified cardiomyocytes should enhance the reliability of results from human iPSC-based in vitro disease modeling studies and drug screening assays.

Here, we describe a robust protocol for human cardiomyocyte derivation that combines small molecule-modulated cardiac differentiation and glucose deprivation-mediated cardiomyocyte purification, enabling production of purified cardiomyocytes for the purposes of cardiovascular disease modeling and drug screening.

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have become an important cell source to address the lack of primary cardiomyocytes ...

Three-dimensional Quantification of Dendritic Spines from Pyramidal Neurons Derived from Human Induced Pluripotent Stem Cells

Dendritic spines are small protrusions that correspond to the post-synaptic compartments of excitatory synapses in the central nervous system. They are distributed along the dendrites. Their morphology is largely dependent on neuronal activity, and they are dynamic. Dendritic spines express glutamatergic receptors (AMPA and NMDA receptors) on their surface and at the levels of postsynaptic densities. Each spine allows the neuron to control its state and local activity independently. Spine morphologies have been extensively studied in glutamatergic pyramidal cells of the brain cortex, using both in vivo approaches and neuronal cultures obtained from rodent tissues. Neuropathological conditions can be associated to altered spine induction and maturation, as shown in rodent cultured neurons and one-dimensional quantitative analysis 1. The present study describes a protocol for the 3D quantitative analysis of spine morphologies using human cortical neurons derived from neural stem cells (late cortical progenitors). These cells were initially obtained from induced&#160;pluripotent stem cells. This protocol allows the analysis of spine morphologies at different culture periods, and with possible comparison between induced&#160;pluripotent stem cells obtained from control individuals with those obtained from patients with psychiatric diseases.

Dendritic spines of pyramidal neurons are the sites of most excitatory synapses in mammalian brain cortex. This method describes a 3D quantitative analysis of spine morphologies in human cortical pyramidal glutamatergic neurons derived from induced&#160;pluripotent stem cells.

Dendritic spines are small protrusions that correspond to the post-synaptic compartments of excitatory synapses in the central nervous system. They are ...

Generation of Induced Pluripotent Stem Cells from Human Peripheral T Cells Using Sendai Virus in Feeder-free Conditions

Recently, iPSCs have attracted attention as a new source of cells for regenerative therapies. Although the initial method for generating iPSCs relied on dermal fibroblasts obtained by invasive biopsy and retroviral genomic insertion of transgenes, there have been many efforts to avoid these disadvantages. Human peripheral T cells are a unique cell source for generating iPSCs. iPSCs derived from T cells contain rearrangements of the T cell receptor (TCR) genes and are a source of antigen-specific T cells. Additionally, T cell receptor rearrangement in the genome has the potential to label individual cell lines and distinguish between transplanted and donor cells. For safe clinical application of iPSCs, it is important to minimize the risk of exposing newly generated iPSCs to harmful agents. Although fetal bovine serum and feeder cells have been essential for pluripotent stem cell culture, it is preferable to remove them from the culture system to reduce the risk of unpredictable pathogenicity. To address this, we have established a protocol for generating iPSCs from human peripheral T cells using Sendai virus to reduce the risk of exposing iPSCs to undefined pathogens. Although handling Sendai virus requires equipment with the appropriate biosafety level, Sendai virus infects activated T cells without genome insertion, yet with high efficiency. In this protocol, we demonstrate the generation of iPSCs from human peripheral T cells in feeder-free conditions using a combination of activated T cell culture and Sendai virus.

This protocol describes how to generate induced pluripotent stem cells (iPSCs) from human peripheral T cells in feeder-free conditions using a combination of matrigel and Sendai virus vectors containing reprogramming factors.

Recently, iPSCs have attracted attention as a new source of cells for regenerative therapies. Although the initial method for generating iPSCs relied on ...

Defined and Scalable Generation of Hepatocyte-like Cells from Human Pluripotent Stem Cells

Human pluripotent stem cells (hPSCs) possess great value for biomedical research. hPSCs can be scaled and differentiated to all cell types found in the human body. The differentiation of hPSCs to human hepatocyte-like cells (HLCs) has been extensively studied, and efficient differentiation protocols have been established. The combination of extracellular matrix and biological stimuli, including growth factors, cytokines, and small molecules, have made it possible to generate HLCs that resemble primary human hepatocytes. However, the majority of procedures still employ undefined components, giving rise to batch-to-batch variation. This serves as a significant barrier to the application of the technology. To tackle this issue, we developed a defined system for hepatocyte differentiation using human recombinant laminins as extracellular matrices in combination with a serum-free differentiation process. Highly efficient hepatocyte specification was achieved, with demonstrated improvements in both HLC function and phenotype. Importantly, this system is easy to scale up using research and GMP-grade hPSC lines&#160;promising advances in cell-based modelling and therapies.

The method presented here describes a scalable and good manufacturing practice (GMP)-ready differentiation system to generate human hepatocyte-like cells from pluripotent stem cells. It serves as a cost-effective and standardized system to generate human hepatocyte-like cells for basic and applied human liver research.

Human pluripotent stem cells (hPSCs) possess great value for biomedical research. hPSCs can be scaled and differentiated to all cell types found in the ...

Integration Free Derivation of Human Induced Pluripotent Stem Cells Using Laminin 521 Matrix

Xeno-free and fully defined conditions are key parameters for robust and reproducible generation of homogenous human induced pluripotent stem (hiPS) cells. Maintenance of hiPS cells on feeder cells or undefined matrices are susceptible to batch variances, pathogenic contamination and risk of immunogenicity. Utilizing the defined recombinant human laminin 521 (LN-521) matrix in combination with xeno-free and defined media formulations reduces variability and allows for the consistent generation of hiPS cells. The Sendai virus (SeV) vector is a non-integrating RNA-based system, thus circumventing concerns associated with the potential disruptive effect on genome integrity integrating vectors can have. Furthermore, these vectors have demonstrated relatively high efficiency in the reprogramming of dermal fibroblasts. In addition, enzymatic single cell passaging of cells facilitates homogeneous maintenance of hiPS cells without substantial prior experience of stem cell culture. Here we describe a protocol that has been extensively tested and developed with a focus on reproducibility and ease of use, providing a robust and practical way to generate defined and xeno-free human hiPS cells from fibroblasts.

Robust derivation of human induced pluripotent stem (hiPS) cells was achieved by using non-integrating Sendai virus (SeV) vector mediated reprogramming of dermal fibroblasts. hiPS cell maintenance and clonal expansion was performed using xeno-free and chemically defined culture conditions with recombinant human laminin 521 (LN-521) matrix and Essential E8 (E8) Medium.

Xeno-free and fully defined conditions are key parameters for robust and reproducible generation of homogenous human induced pluripotent stem (hiPS) ...

Rapid, Directed Differentiation of Retinal Pigment Epithelial Cells from Human Embryonic or Induced Pluripotent Stem Cells

We describe a robust method to direct the differentiation of pluripotent stem cells into retinal pigment epithelial cells (RPE). The purpose of providing a detailed and thorough protocol is to clearly demonstrate each step and to make this readily available to researchers in the field. This protocol results in a homogenous layer of RPE with minimal or no manual dissection needed. The method presented here has been shown to be effective for induced pluripotent stem cells (iPSC) and human embryonic stem cells. Additionally, we describe methods for cryopreservation of intermediate cell banks that allow long-term storage. RPE generated using this protocol might be useful for iPSC disease-in-a-dish modeling or clinical application.

This protocol describes how to produce retinal pigment epithelial cells (RPE) from pluripotent stem cells. The method uses a combination of growth factors and small molecules to direct the differentiation of stem cells into immature RPE in fourteen days and mature, functional RPE after three months.

We describe a robust method to direct the differentiation of pluripotent stem cells into retinal pigment epithelial cells (RPE). The purpose of providing ...

Efficient Differentiation of Human Pluripotent Stem Cells into Liver Cells

The liver detoxifies harmful substances, secretes vital proteins, and executes key metabolic activities, thus sustaining life. Consequently, liver failure&#8212;which can be caused by chronic alcohol intake, hepatitis, acute poisoning, or other insults&#8212;is a severe condition that can culminate in bleeding, jaundice, coma, and eventually death. However, approaches to treat liver failure, as well as studies of liver function and disease, have been stymied in part by the lack of a plentiful supply of human liver cells. To this end, this protocol details the efficient differentiation of human pluripotent stem cells (hPSCs) into hepatocyte-like cells, guided by a developmental roadmap that describes how liver fate is specified across six consecutive differentiation steps. By manipulating developmental signaling pathways to promote liver differentiation and to explicitly suppress the formation of unwanted cell fates, this method efficiently generates populations of human liver bud progenitors and hepatocyte-like cells by days 6 and 18 of PSC differentiation, respectively. This is achieved through the temporally-precise control of developmental signaling pathways, exerted by small molecules and growth factors in a serum-free culture medium. Differentiation in this system occurs in monolayers and yields hepatocyte-like cells that express characteristic hepatocyte enzymes and have the ability to engraft a mouse model of chronic liver failure. The ability to efficiently generate large numbers of human liver cells in vitro has ramifications for treatment of liver failure, for drug screening, and for mechanistic studies of liver disease.

This protocol details a monolayer, serum-free method to efficiently generate hepatocyte-like cells from human pluripotent stem cells (hPSCs) in 18 days. This entails six steps as hPSCs sequentially differentiate into intermediate cell-types such as the primitive streak, definitive endoderm, posterior foregut and liver bud progenitors before forming hepatocyte-like cells.

The liver detoxifies harmful substances, secretes vital proteins, and executes key metabolic activities, thus sustaining life. Consequently, liver ...

In Vitro Generation of Somite Derivatives from Human Induced Pluripotent Stem Cells

In response to signals such as WNTs, bone morphogenetic proteins (BMPs), and sonic hedgehog (SHH) secreted from surrounding tissues, somites (SMs) give rise to multiple cell types, including the myotome (MYO), sclerotome (SCL), dermatome (D), and syndetome (SYN), which in turn develop into skeletal muscle, axial skeleton, dorsal dermis, and axial tendon/ligament, respectively. Therefore, the generation of SMs and their derivatives from human induced pluripotent stem cells (iPSCs) is critical to obtain pluripotent stem cells (PSCs) for application in regenerative medicine and for disease research in the field of orthopedic surgery. Although the induction protocols for MYO and SCL from PSCs have been previously reported by several researchers, no study has yet demonstrated the induction of SYN and D from iPSCs. Therefore, efficient induction of fully competent SMs remains a major challenge. Here, we recapitulate human SM patterning with human iPSCs in vitro by mimicking the signaling environment during chick/mouse SM development, and report on methods of systematic induction of SM derivatives (MYO, SCL, D, and SYN) from human iPSCs under chemically defined conditions through the presomitic mesoderm (PSM) and SM states. Knowledge regarding chick/mouse&#160;SM development was successfully applied to the induction of SMs with human iPSCs. This method could be a novel tool for studying human somitogenesis and patterning without the use of embryos and for cell-based therapy and disease modeling.

We present here a protocol for the differentiation of human induced pluripotent stem cells into each somite derivative (myotome, sclerotome, dermatome, and syndetome) in chemically defined conditions, which has applications in future disease modeling and cell-based therapies in orthopedic surgery.

In response to signals such as WNTs, bone morphogenetic proteins (BMPs), and sonic hedgehog (SHH) secreted from surrounding tissues, somites (SMs) give ...