The authors would like to thank Soon-Cheol Hong (M.D., Ph.D., Associate Professor, Department of Obstetrics and Gynecology, Medical College Korea University) for providing placental tissue. This work was supported in part by grants (R1211902) from the National Research Foundation of Korea (NRF), Republic of Korea.

Ethics statement: The human placenta study was conducted prospectively, with the approval of the Institutional Review Board for human research of the Korea University (AN09085-001). All experiments were performed in a Clean Germ-Free Room facility at the Korea University Medical Center. The experimental design and procedures using hPSCs were approved by the Institutional Review Board of the Korea University Medical Center (AN12277-003).
1. Preparation of Instruments, Culture Media, and Dishes
<ol>
	<li>Coat all the culture dishes with 0.1% gelatin. Autoclave phosphate-buffered saline (PBS) and forceps. Sterilize surgical scissors, microcentrifuge tubes, and gauze at 121 &#176;C under 15lb psi for more than 15 min.</li>
	<li>Prepared pre-warmed 0.25% trypsin-ethylene amine tetra-acetic acid (trypsin-EDTA) and pre-warmed filtered culture media (DMEM) containing 20% fetal bovine serum (FBS), 100 U/ml penicillin, and 100 g/ml streptomycin before commencing procedures.</li>
</ol>
2. Cell Isolation from Human Placenta
<ol>
	<li>Obtain placental tissue, after caesarean section delivery, from healthy pregnant women undergoing normal or therapeutic abortion at 7&#8211;32 weeks of gestation after obtaining written informed consent.</li>
	<li>Have the obstetric specialist surgically separate human placenta chorionic plates (HPCs) from the placenta; incubate these in 0.25% trypsin-EDTA at 37 &#176;C for 20 min, and then wash with 5 ml PBS.</li>
	<li>Isolate chorionic villi from HPCs using scissors; mince the villi and wash them three times with 1ml PBS. After mincing, place the chorionic villi into a microfuge tube using a pipette tip; wash the samples with 500 &#181;l PBS by pipetting up and down, and centrifuge the tubes for 120 x g for 3 min. Wash tissues twice with 500 &#181;l of pre-warmed culture medium.</li>
	<li>Culture cells in medium on gelatin-coated plates at 37 &#176;C, in 5% CO2, and under 95% humidity. Pre-coat all plates with 0.1% gelatin for 1 hr at 37 &#176;C. Colonies of fibroblast-like cells will form and adherent growth approximately 5&#8211;7 days after commencing culture in the same medium.</li>
	<li>Exchange the medium every 2&#8211;3 days until the third passage. During culture, removing cell debris floating in the culture medium; growing placental fibroblasts will attach to the plate. Culture the fibroblast-like cells derived from the HPC up to the 10th passage and then harvest them for hESC cultures after trypsinization and mitomycin-C (10 &#181;g/ml) treatment.</li>
	<li>Before freezing HPCs as stock samples, use reverse transcription&#8211;polymerase chain reaction (RT-PCR) to confirm that HPCs are not contaminated with pathogens that commonly infect the placenta, including mycoplasma (M. fermentans, M. hyorhinis, M. Arginine, M. orale, M. salivarium, M. hominis, M. pulmonis, M. arthritidis, M. neurolyticum, M. hyopneumoniae, and M. capricolum) and the bacterial species, Ureaplasmaurealyticum, by using a mycoplasma detection kit.
	<ol>
		<li>Follow the manufacturer&#8217;s instructions to perform RT-PCR, use all primers and mixtures provided in the kit. Use the supernatants of the cells that have been cultivated for 36 days for mycoplasma detection. Add 3 &#181;l of these samples to the PCR mixtures and perform the 1st PCR procedure for 35 cycles, each consisting of 94 &#176;C for 30 sec, 55 &#176;C for 2 min, and 72 &#176;C for 1 min.</li>
		<li>Carefully add 0.5 &#181;l of the 1st PCR product to the PCR mixture and perform the 2nd PCR procedure for 30 cycles using the same conditions as before. Analyze the amplified products by 1% agarose gel electrophoresis; apply 10 &#181;l of each of the 1st and 2nd PCR products to the gels.</li>
	</ol>
	</li>
	<li>If HPCs are found to be contaminated with pathogens, eliminate these using a combination of antibiotics (BM-Cyclin), following the manufacturer&#39;s instructions. Add new medium containing 10 &#181;g/ml of BM-Cyclin 1 for 3 days, and then treat the cells with 5 &#181;g/ml BM-Cyclin 2 for another 4 days. Repeat this cycle twice and then check for mycoplasma contamination again.</li>
</ol>
3. Harvesting Human Placenta-derived Cells Conditioned Medium (hPCCM)
<ol>
	<li>After excluding contamination, treat the attached cells (85-90% confluence; (1.5 &#215; 107 cells/flask) with mitomycin-C (10 &#181;g/ml) for 2 hr and 30 min, and washed the cells three times with 10 ml PBS. Incubate the cells with pre-warmed medium without mitomycin-C for 24 hr.</li>
	<li>One day after treatment, incubate cells in 10 ml medium (DMEM-F12 supplemented with 20% Knock-Out Serum Replacement [KOSR], 0.1 mM &#946;-mercaptoethanol, 1% NEAA, and 1% penicillin&#8211;streptomycin). After 24 hr of incubation, harvest CM in a 15-ml conical tube and filter the CM using a 0.22 &#181;m syringe filter.</li>
	<li>Add another 10 ml of new medium and incubation. Collect all supernatants from the cultures every day for 1 week and freeze the harvested medium at &#8211;80 &#176;C. Avoid repeated freeze-thaw cycles.</li>
</ol>
4.&#160;Culture of Human Embryonic Stem Cells (hESCs) and Induction of Pluripotent Stem Cells (iPSCs)
<ol>
	<li>Obtain Human embryonic stem cell lines, H1 and H9 cells (listed in the NIH hESC registry under the name WA01 and WA09, respectively) and induced-pluripotent stem cell iPSC-1: iPS(foreskin)-1 and iPSC-2 (IISH1i-BM) from the WiCell Research Institute (Madison, WI, USA). Cells should be thawed and cultured following the manufacturer&#8217;s instructions.</li>
	<li>For the control group, culture cells on Basement Membrane Matrix-coated dishes in widely used feeder-free and serum-free defined culture medium at 37 &#176;C and in 5% CO2. Initially, seed 80-100 clumps of hPSCs in 35-mm dishes. Grow cells in these dishes until 70-80% confluence and routinely passage cells for sub-culturing once every 5&#8211;6 days, using mechanical or enzymatic methods (Dispase). Wash cells twice with medium and plate them at a ratio of 1:4. Replace the medium with fresh medium every day.</li>
	<li>For the experimental groups, culture cells in hPCCM on dishes pre-coated with 0.1% gelatin and perform routine passaging once every 5 days, either mechanically or enzymatically. Plate cells at ratios in the range of 1:6&#8211;1:10. hPSCs attach to the gelatin within 2 days after transfer. Replace the medium with fresh medium daily.</li>
</ol>
5. Characterization of Human Pluripotent Stem Cells
NOTE: Characterize hPSCs using several methods, such as alkaline phosphatase staining, immunocytochemistry, Quantitative real-time PCR (qRT-PCR), and western blotting.
<ol>
	<li>Immunofluorescence staining
	<ol>
		<li>For immunofluorescence staining, culture hPSCs and fix the cells in 8-well slide chambers with 4% (w/v) paraformaldehyde for 10 min; then, permeabilized the cells with 0.1% (v/v) Triton-X100 for 15 min, and block the cells for 1 hr with 3% (v/v) normal horse serum in PBS containing 0.1% (v/v) Tween-20. Wash PBS twice for 5 min between every step.</li>
		<li>Incubate cells with the primary antibody (OCT-4, SSEA4, TRA-1-81, TRA-1-60, dilution of 1:1,000) O/N at 4 &#176;C and with the secondary antibody.</li>
		<li>Before mounting, incubate cells with 4&#8242;,6-diamidino-2-phenylindole (DAPI) for 5 min in the dark. Wash cells stringently three times for 5 min each and dry cells completely, in the dark. Preserve cells in fluorescence mounting medium and observe them under a fluorescence microscope.</li>
	</ol>
	</li>
	<li>qRT-PCR
	<ol>
		<li>Isolate total RNA from cells using an RNeasy mini kit according to manufacturer&#39;s specifications and quantify the extracted RNA using a Nano Drop Spectrophotometer.</li>
		<li>Synthesize cDNA by adding 2 &#181;g of the total RNA to a 20-&#181;l reaction mixture containing oligo(dT) primers and Superscript II reverse transcriptase; follow the manufacturer&#8217;s instructions in this procedure.</li>
		<li>Amplify the synthesized cDNA with a Bio-Rad iCycler iQ system, using iQ SYBR Green qPCR Master Mix and the primer sequences described in Supplemental Table S1. Normalize the cycle threshold values of the genes of interest to those of glyceraldehyde-3-phosphate dehydrogenase (GAPDH).</li>
	</ol>
	</li>
	<li>Alkaline phosphatase (AP) staining
	<ol>
		<li>Detect AP activity using the ES Cell Characterization Kit, according to the manufacturer&#8217;s protocol.</li>
		<li>On day 5, aspirate the media and fix the hPSCs with 4% paraformaldehyde in PBS for 12 min. Do not overfix; fixing cells for longer than 2 min will result in the inactivation of alkaline phosphatase. Aspirate the fixative and rinse with 1x Rinse Buffer. Do not allow wells to dry between steps.</li>
		<li>Add enough staining solution to cover each well (1 ml per well of a 35 mm dish). Incubate plates in the dark at RT&#160;for 15 min.</li>
		<li>After incubation, wash dishes with 1x Rinse Buffer. Cover cells with 1x PBS to prevent drying and examine and image the stained cells using an Olympus microscope.</li>
	</ol>
	</li>
	<li>Western Blot
	<ol>
		<li>Perform western blot analysis as previously described in9. Briefly, determine protein concentrations in cell lysates. Resolve equal amounts of protein on a sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gel and transfer the proteins onto a polyvinylidene fluoride (PVDF) membrane.</li>
		<li>Block the blot and probe it O/N with different primary antibodies at 4 &#176;C; subsequently incubate the blot with HRP-conjugated secondary antibodies for 1 hr. Wash the membrane three times for 10 min each time between incubations. Detect signals using an ECL reagent.</li>
	</ol>
	</li>
	<li>Short Tandem Repeat (STR) Analysis
	<ol>
		<li>hPSCs were harvested from the control and experimental groups at the same passage. Genomic DNA was extracted using a DNA Micro kit, according to the manufacturer&#8217;s instructions.</li>
		<li>Amplify the genomic DNA for 16 different genetic loci using the AmpF/STR PCR Amplification Kit, according to the manufacturer&#8217;s specifications and capillary electrophoresis was performed using a Genetic Analyzer.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Xu, 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=Feeder-free+growth+of+undifferentiated+human+embryonic+stem+cells.">Feeder-free growth of undifferentiated human embryonic stem cells.</a> Nat Biotechnol. 19 (10), 971-974 (2001).</li><li>Amit, M. C., Shakiri, V., Margulets, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Itskovitz-Eldor+Feeder+layer+and+serum-free+culture+of+human+embryonic+stem+cells.">Itskovitz-Eldor Feeder layer and serum-free culture of human embryonic stem cells.</a> Biol Reprod. 70 (3), 837-845 (2004).</li><li>Nagaoka, M., Si-Tayeb, K., Akaike, T., Duncan, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Culture+of+human+pluripotent+stem+cells+using+completely+defined+conditions+on+a+recombinant+E-cadherin+substratum.">Culture of human pluripotent stem cells using completely defined conditions on a recombinant E-cadherin substratum.</a> BMC Dev Biol. 10, 60 (2010).</li><li>Jin, S., Yao, H., Weber, J. L., Melkoumian, Z. K., Ye, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+synthetic,+xeno-free+peptide+surface+for+expansion+and+directed+differentiation+of+human+induced+pluripotent+stem+cells.">A synthetic, xeno-free peptide surface for expansion and directed differentiation of human induced pluripotent stem cells.</a> PLoS One. 7 (11), e50880 (2012).</li><li>Xu, R. 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=Basic+FGF+and+suppression+of+BMP+signaling+sustain+undifferentiated+proliferation+of+human+ES+cells.">Basic FGF and suppression of BMP signaling sustain undifferentiated proliferation of human ES cells.</a> Nat Methods. 2 (3), 185-190 (2005).</li><li>Xu, 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=Basic+fibroblast+growth+factor+supports+undifferentiated+human+embryonic+stem+cell+growth+without+conditioned+medium.">Basic fibroblast growth factor supports undifferentiated human embryonic stem cell growth without conditioned medium.</a> Stem Cells. 23 (3), 315-323 (2005).</li><li>Levenstein, M. E., 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=Basic+fibroblast+growth+factor+support+of+human+embryonic+stem+cell+self-renewal.">Basic fibroblast growth factor support of human embryonic stem cell self-renewal.</a> Stem Cells. 24 (3), 568-574 (2006).</li><li>Park, Y., 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+feeder+cells+can+support+the+undifferentiated+growth+of+human+and+mouse+embryonic+stem+cells+using+their+own+basic+fibroblast+growth+factors.">Human feeder cells can support the undifferentiated growth of human and mouse embryonic stem cells using their own basic fibroblast growth factors.</a> Stem Cells Dev. 20 (11), 1901-1910 (2011).</li><li>Park, Y., 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=The+efficacy+of+human+placenta+as+a+source+of+the+universal+feeder+in+human+and+mouse+pluripotent+stem+cell+culture.">The efficacy of human placenta as a source of the universal feeder in human and mouse pluripotent stem cell culture.</a> Cell Reprogram. 12 (3), 315-328 (2010).</li><li>Park, Y., 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=Undifferentiated+propagation+of+the+human+embryonic+stem+cell+lines,+H1+and+HSF6,+on+human+placenta-derived+feeder+cells+without+basic+fibroblast+growth+factor+supplementation.">Undifferentiated propagation of the human embryonic stem cell lines, H1 and HSF6, on human placenta-derived feeder cells without basic fibroblast growth factor supplementation.</a> Stem Cells Dev. 19 (11), 1713-1722 (2010).</li><li>Seok, 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=Human+placenta-derived+feeders+support+prolonged+undifferentiated+propagation+of+a+human+embryonic+stem+cell+line,+SNUhES3:+comparison+with+human+bone+marrow-derived+feeders.">Human placenta-derived feeders support prolonged undifferentiated propagation of a human embryonic stem cell line, SNUhES3: comparison with human bone marrow-derived feeders.</a> Stem Cells Dev. 16 (3), 421-428 (2007).</li><li>Levenstein, M. E., 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=Basic+fibroblast+growth+factor+support+of+human+embryonic+stem+cell+self-renewal.">Basic fibroblast growth factor support of human embryonic stem cell self-renewal.</a> Stem Cells. 24 (3), 568-574 (2006).</li><li>Xu, R. H., Peck, R. M., Li, D. S., Feng, X., Ludwig, T., Thomson, J. A., 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=Basic+FGF+and+suppression+of+BMP+signaling+sustain+undifferentiated+proliferation+of+human+ES+cells.">Basic FGF and suppression of BMP signaling sustain undifferentiated proliferation of human ES cells.</a> Nat Methods. 2 (3), 185-190 (2005).</li><li>Mahmood, A., Harkness, L., Schrøder, H. D., Abdallah, B. M., Kassem, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+differentiation+of+stem+cells+mesenchymal+progenitors+by+inhibition+of+TGF-beta/activin/nodal+using+SB-431542.">Enhanced differentiation of stem cells mesenchymal progenitors by inhibition of TGF-beta/activin/nodal using SB-431542.</a> J Bone Miner Res. 25 (6), 1216-1233 (2010).</li></ol>

The authors indicate no conflicts of interest.

This model was developed to successfully propagate hPSCs, while maintaining their characteristics, in humanized feeder-free culture conditions without the addition of exogenous recombinant growth factors such as bFGF or insulin, enabling the manipulation of hPSCs in a humanized microenvironment. Exogenous bFGF supplementation is common and the application of substrata such as Matrigel or laminin is essential for feeder-free culturing of hPSCs14.
This protocol is simple and easy to i...

The goal of this protocol is the propagation of human pluripotent stem cells (hPSCs) including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (iPSCs) in fully humanized ex vivo feeder-free conditions without requiring additional exogenous supplementation and synthetic substrates. To date, the development of ex vivo hPSC culture models, that enable the introduction of culture products to the clinic, has been a major concern in stem cell research. Specifically, two critical problems need to be addressed. First, a humanized ex vivo culture system for the propagation of hPSCs that obviates the risk of contamination by animal cell products is needed. Second, a feeder-free culture model is needed to facilitate easy and economic mass production of hPSCs. For therapeutic applications of hPSCs, it is necessary to identify the factors that regulate their self-renewal and differentiation.
Since Xu et al. initially reported the feasibility of using conditioned media (CM) derived from mouse embryonic fibroblasts (MEF) to grow hESCs on Matrigel1, many studies have examined optimal ex vivo propagation methods for hPSCs2-4. However, an ideal humanized ex vivo feeder-free hPSC propagation system has not been developed because current methods require additional exogenous substrates including bFGF and insulin, well-known hPSC-sustaining factors, in culture media5-7. Moreover, synthetic substrata such as Matrigel or laminin are used in all feeder-free cultures.
The rationale behind the development and use of this protocol is based on our previous studies showing that human placenta chorion cells excellently support the propagation of hPSCs without bFGF supplementation8-11. This protocol has a number of advantages including its simplicity with respect to handling and its cost-effectiveness, and it is a near-perfect humanized culture that enables hPSC propagation without exogenous synthetic substrates. The application of human placenta-derived CM (hPCCM) for hPSCs involves 3 steps. First, chorion cells are isolated from the human placenta and cultured. Second, hPCCM is produced from cultured cells. Third, hPSCs are cultured using hPCCM and their characteristics are confirmed. 
This protocol will facilitate clinical applications of hPSCs and studies of the mechanisms of hPSC proliferation and attachment. In this paper, the protocol for the successful propagation of hPSCs in hPCCM on a gelatin-coated dish is presented.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Mitomycin-C</td>
			<td>Sigma-Aldrich Corporation</td>
			<td>M4287</td>
			<td>10ug/ml</td>
		</tr>
		<tr>
			<td>Mycoplasma detection kit</td>
			<td>TaKaRa Bio Inc.</td>
			<td>#6601</td>
			<td></td>
		</tr>
		<tr>
			<td>Matrigel</td>
			<td>BD Biosciences</td>
			<td>#354277</td>
			<td></td>
		</tr>
		<tr>
			<td>mTeSR1</td>
			<td>STEMCELL Technologies Inc.</td>
			<td>#05850</td>
			<td></td>
		</tr>
		<tr>
			<td>Dispase</td>
			<td>Worthington Biochemical Corporation</td>
			<td>LS02100</td>
			<td>1mg/ml</td>
		</tr>
		<tr>
			<td>Gelatin</td>
			<td>Sigma-Aldrich Corporation</td>
			<td>G2500</td>
			<td>0.10%</td>
		</tr>
		<tr>
			<td>BM-Cyclin</td>
			<td>Roche</td>
			<td>799 050</td>
			<td>10ug/ml</td>
		</tr>
		<tr>
			<td>RNeasy mini kit&#160;</td>
			<td>Qiagen</td>
			<td>74104</td>
			<td></td>
		</tr>
		<tr>
			<td>Nano Drop Spectrophotometer</td>
			<td>Thermo Fisher Scientific Inc</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>iQ SYBR Green qPCR Master Mix&#160;</td>
			<td>Bio-Rad Laboratories</td>
			<td>#170-8882AP</td>
			<td></td>
		</tr>
		<tr>
			<td>ES Cell Characterization kit</td>
			<td>Chemicon International, Inc.,</td>
			<td>SCR001</td>
			<td></td>
		</tr>
		<tr>
			<td>Power cDNA Synthesis Kit&#160;</td>
			<td>iNtRON Biotechnology</td>
			<td>25011</td>
			<td></td>
		</tr>
		<tr>
			<td>QIAamp&#174; DNA Micro kit</td>
			<td>Qiagen</td>
			<td>56304</td>
			<td></td>
		</tr>
		<tr>
			<td>AmpF/STR&#174; Identifiler&#174; PCR Amplification kit</td>
			<td>Applied Biosystems Inc.</td>
			<td>4322288</td>
			<td></td>
		</tr>
		<tr>
			<td>Applied Biosystems&#174; 3130xl Genetic Analyzer&#160;</td>
			<td>Applied Biosystems Inc.</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

a novel culture model for human pluripotent stem cell propagation on gelatin in placenta-conditioned media

The propagation of human pluripotent stem cells (hPSCs) in conditioned medium derived from human cells in feeder-free culture conditions has been of interest. Nevertheless, an ideal humanized ex vivo feeder-free propagation method for hPSCs has not been developed; currently, additional exogenous substrates including basic fibroblast growth factor (bFGF), a master hPSC-sustaining factor, is added to all of culture media and synthetic substrata such as Matrigel or laminin are used in all feeder-free cultures. Recently, our group developed a simple and efficient protocol for the propagation of hPSCs using only conditioned media derived from the human placenta on a gelatin-coated dish without additional exogenous supplementation or synthetic substrata specific to hPSCs. This protocol has not been reported previously and might enable researchers to propagate hPSCs efficiently in humanized culture conditions. Additionally, this model obviates hPSC contamination risks by animal products such as viruses or unknown proteins. Furthermore, this system facilitates easy mass production of hPSCs using the gelatin coating, which is simple to handle, dramatically decreases the overall costs of ex vivo hPSC maintenance.

One advantage of this hPSC propagation method is that it uses components secreted from human cells. A most ciritical step in the protocol is the isolation and culture of human placenta-derived cells. This requires and accurate dissection from a precise part of HPC plate villi. Figure 1 shows the procedure for human placenta-derived cell isolation. This process is simple and convenient for the isolation of cells, and can easily be performed within 1 hr. As described in Figure 2, tissues a...

Watch this Scientific Journal Video about A Novel Culture Model for Human Pluripotent Stem Cell Propagation on Gelatin in Placenta-conditioned Media at JoVE.com

A Novel Culture Model for Human Pluripotent Stem Cell Propagation on Gelatin in Placenta-conditioned Media

This protocol provides a simple and efficient way to propagate human pluripotent stem cells (hPSCs) using only conditioned media derived from the human placenta in a gelatin-coated dish without additional exogenous supplementation or hPSC-specific synthetic substrata.

The propagation of human pluripotent stem cells (hPSCs) in conditioned medium derived from human cells in feeder-free culture conditions has been of ...

a-novel-culture-model-for-human-pluripotent-stem-cell-propagation-on

Research

JoVE Journal

Developmental Biology

7.8K Views.  Graduate School of Medicine, Korea University. This protocol provides a simple and efficient way to propagate human pluripotent stem cells (hPSCs) using only conditioned media derived from the human placenta in a gelatin-coated dish without additional exogenous supplementation or hPSC-specific synthetic substrata.

Video: A Novel Culture Model for Human Pluripotent Stem Cell Propagation on Gelatin in Placenta-conditioned Media

Alginate Encapsulation of Pluripotent Stem Cells Using a Co-axial Nozzle

Pluripotent stem cells (PS cells) are the focus of intense research due to their role in regenerative medicine and drug screening. However, the development of a mass culture system would be required for using PS cells in these applications. Suspension culture is one promising culture method for the mass production of PS cells, although some issues such as controlling aggregation and limiting shear stress from the culture medium are still unsolved. In order to solve these problems, we developed a method of calcium alginate (Alg-Ca) encapsulation using a co-axial nozzle. This method can control the size of the capsules easily by co-flowing N2 gas. The controllable capsule diameter must be larger than 500 &#181;m because too high a flow rate of N2 gas causes the breakdown of droplets and thus heterogeneous-sized capsules. Moreover, a low concentration of Alg-Na and CaCl2 causes non-spherical capsules. Although an Alg-Ca capsule without a coating of Alg-PLL easily dissolves enabling the collection of cells, they can also potentially leak out from capsules lacking an Alg-PLL coating. Indeed, an alginate-PLL coating can prevent cellular leakage but is also hard to break. This technology can be used to research the stem cell niche as well as the mass production of PS cells because encapsulation can modify the micro-environment surrounding cells including the extracellular matrix and the concentration of secreted factors.

We established a method of encapsulating pluripotent stem cells (PS cells) into alginate hydrogel capsules using a co-axial nozzle. This prevents cells from aggregating excessively and limits the shear stress experienced by cells in suspension culture. The technique is applicable to the mass production of PS cells as well as research on stem cell niche.

Pluripotent stem cells (PS cells) are the focus of intense research due to their role in regenerative medicine and drug screening.  However, the ...

Culturing Human Pluripotent and Neural Stem Cells in an Enclosed Cell Culture System for Basic and Preclinical Research

This paper describes how to use a custom manufactured, commercially available enclosed cell culture system for basic and preclinical research. Biosafety cabinets (BSCs) and incubators have long been the standard for culturing and expanding cell lines for basic and preclinical research. However, as the focus of many stem cell laboratories shifts from basic research to clinical translation, additional requirements are needed of the cell culturing system. All processes must be well documented and have exceptional requirements for sterility and reproducibility. In traditional incubators, gas concentrations and temperatures widely fluctuate anytime the cells are removed for feeding, passaging, or other manipulations. Such interruptions contribute to an environment that is not the standard for cGMP and GLP guidelines. These interruptions must be minimized especially when cells are utilized for therapeutic purposes. The motivation to move from the standard BSC and incubator system to a closed system is that such interruptions can be made negligible. Closed systems provide a work space to feed and manipulate cell cultures and maintain them in a controlled environment where temperature and gas concentrations are consistent. This way, pluripotent and multipotent stem cells can be maintained at optimum health from the moment of their derivation all the way to their eventual use in therapy.

Here is a protocol to grow pluripotent stem cells (PSC) and neural stem cells (NSC) in an enclosed cell culture system that permits maximum sterility and reproducibility, replacing the traditional biosafety cabinet and incubator. This equipment meets clinical good manufacturing practice (cGMP) and clinical good lab practice (cGLP) guidelines.

This paper describes how to use a custom manufactured, commercially available enclosed cell culture system for basic and preclinical research. Biosafety ...

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 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 ...

Large-Scale Production of Cardiomyocytes from Human Pluripotent Stem Cells Using a Highly Reproducible Small Molecule-Based Differentiation Protocol

Maximizing the benefit of human pluripotent stem cells (hPSCs) for research, disease modeling, pharmaceutical and clinical applications requires robust methods for the large-scale production of functional cell types, including cardiomyocytes. Here we demonstrate that the temporal manipulation of WNT, TGF-&#946;, and SHH signaling pathways leads to highly efficient cardiomyocyte differentiation of single-cell passaged hPSC lines in both static suspension and stirred suspension bioreactor systems. Employing this strategy resulted in ~ 100% beating spheroids, consistently containing &#62; 80% cardiac troponin T-positive cells after 15 days of culture, validated in multiple hPSC lines. We also report on a variation of this protocol for use with cell lines not currently adapted to single-cell passaging, the success of which has been verified in 42 hPSC lines. Cardiomyocytes generated using these protocols express lineage-specific markers and show expected electrophysiological functionalities. Our protocol presents a simple, efficient and robust platform for the large-scale production of human cardiomyocytes.

Here, we present a robust, fast and scalable cardiomyocyte differentiation protocol for human pluripotent stem cells (hPSCs). Cardiomyocytes derived using this large-scale method can provide sufficient cell numbers for their effective use in human cardiovascular disease modeling, high-throughput drug screening, and potentially clinical applications.

Maximizing the benefit of human pluripotent stem cells (hPSCs) for research, disease modeling, pharmaceutical and clinical applications requires robust ...

Rapid Neuronal Differentiation of Induced Pluripotent Stem Cells for Measuring Network Activity on Micro-electrode Arrays

Neurons derived from human induced Pluripotent Stem Cells (hiPSCs) provide a promising new tool for studying neurological disorders. In the past decade, many protocols for differentiating hiPSCs into neurons have been developed. However, these protocols are often slow with high variability, low reproducibility, and low efficiency. In addition, the neurons obtained with these protocols are often immature and lack adequate functional activity both at the single-cell and network levels unless the neurons are cultured for several months. Partially due to these limitations, the functional properties of hiPSC-derived neuronal networks are still not well characterized. Here, we adapt a recently published protocol that describes production of human neurons from hiPSCs by forced expression of the transcription factor neurogenin-212. This protocol is rapid (yielding mature neurons within 3 weeks) and efficient, with nearly 100% conversion efficiency of transduced cells (&#62;95% of DAPI-positive cells are MAP2 positive). Furthermore, the protocol yields a homogeneous population of excitatory neurons that would allow the investigation of cell-type specific contributions to neurological disorders. We modified the original protocol by generating stably transduced hiPSC cells, giving us explicit control over the total number of neurons. These cells are then used to generate hiPSC-derived neuronal networks on micro-electrode arrays. In this way, the spontaneous electrophysiological activity of hiPSC-derived neuronal networks can be measured and characterized, while retaining interexperimental consistency in terms of cell density. The presented protocol is broadly applicable, especially for mechanistic and pharmacological studies on human neuronal networks.

We modify and implement a previously published protocol describing the rapid, reproducible, and efficient differentiation of human&#160;induced&#160;Pluripotent Stem Cells (hiPSCs) into excitatory cortical neurons12. Specifically, our modification allows for control of neuronal cell density and use on micro-electrode arrays to measure electrophysiological properties at the network level.

Neurons derived from human induced Pluripotent Stem Cells (hiPSCs) provide a promising new tool for studying neurological disorders. In the past decade, ...

A Novel Mammary Fat Pad Transplantation Technique to Visualize the Vessel Generation of Vascular Endothelial Stem Cells

Endothelial cells (ECs) are the fundamental building blocks of the vascular architecture and mediate vascular growth and remodeling to ensure proper vessel development and homeostasis. However, studies on endothelial lineage hierarchy remain elusive due to the lack of tools to gain access as well as to directly evaluate their behavior in vivo. To address this shortcoming, a new tissue model to study angiogenesis using the mammary fat pad has been developed. The mammary gland develops mostly in the postnatal stages, including puberty and pregnancy, during which robust epithelium proliferation is accompanied by extensive vascular remodeling. Mammary fat pads provide space, matrix, and rich angiogenic stimuli from the growing mammary epithelium. Furthermore, mammary fat pads are located outside the peritoneal cavity, making them an easily accessible grafting site for assessing the angiogenic potential of exogenous cells. This work also describes an efficient tracing approach using fluorescent reporter mice to specifically label the targeted population of vascular endothelial stem cells (VESCs) in vivo. This lineage tracing method, coupled with subsequent tissue whole-mount microscopy, enable the direct visualization of targeted cells and their descendants, through which the proliferation capability can be quantified and the differentiation commitment can be fate-mapped. Using these methods, a population of bipotent protein C receptor (Procr) expressing VESCs has recently been identified in multiple vascular systems. Procr+ VESCs, giving rise to both new ECs and pericytes, actively contribute to angiogenesis during development, homeostasis, and injury repair. Overall, this manuscript describes a new mammary fat pad transplantation and in vivo lineage tracing techniques that can be used to evaluate the stem cell properties of VESCs.

This work demonstrates a novel approach to assess the proliferation, differentiation, and vessel-forming potential of vascular endothelial stem cells (VESCs) through mammary fat pad transplantation followed by whole-mount tissue preparation for microscopic observation. A lineage tracing strategy to investigate the behavior of VESCs in vivo is also presented.

Endothelial cells (ECs) are the fundamental building blocks of the vascular architecture and mediate vascular growth and remodeling to ensure proper ...

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 ...

Using Human Induced Pluripotent Stem Cell-derived Hepatocyte-like Cells for Drug Discovery

The ability to differentiate human induced pluripotent stem cells (iPSCs) into hepatocyte-like cells (HLCs) provides new opportunities to study inborn errors in hepatic metabolism. However, to provide a platform that supports the identification of small molecules that can potentially be used to treat liver disease, the procedure requires a culture format that is compatible with screening thousands of compounds. Here, we describe a protocol using completely defined culture conditions, which allow the reproducible differentiation of human iPSCs to hepatocyte-like cells in 96-well tissue culture plates. We also provide an example of using the platform to screen compounds for their ability to lower Apolipoprotein B (APOB) produced from iPSC-derived hepatocytes generated from a familial hypercholesterolemia patient. The availability of a platform that is compatible with drug discovery should allow researchers to identify novel therapeutics for diseases that affect the liver.

The protocol presented here describes a platform for identifying small molecules for the treatment of liver disease. A step-by-step description is presented detailing how to differentiate iPSCs into cells with hepatocyte characteristics in 96-well plates, and to use the cells to screen for small molecules with potential therapeutic activity.

The ability to differentiate human induced pluripotent stem cells (iPSCs) into hepatocyte-like cells (HLCs) provides new opportunities to study inborn ...

A Familial Hypercholesterolemia Human Liver Chimeric Mouse Model Using Induced Pluripotent Stem Cell-derived Hepatocytes

Familial hypercholesterolemia (FH) is mostly caused by low-density lipoprotein receptor (LDLR) mutations and results in an increased risk of early-onset cardiovascular disease due to marked elevation of LDL cholesterol (LDL-C) in blood. Statins are the first line of lipid-lowering drugs for treating FH and other types of hypercholesterolemia, but new approaches are emerging, in particular PCSK9 antibodies, which are now being tested in clinical trials. To explore novel therapeutic approaches for FH, either new drugs or new formulations, we need appropriate in vivo models. However, differences in the lipid metabolic profiles compared to humans are a key problem of the available animal models of FH. To address this issue, we have generated a human liver chimeric mouse model using FH induced pluripotent stem cell (iPSC)-derived hepatocytes (iHeps). We used Ldlr-/-/Rag2-/-/Il2rg-/- (LRG) mice to avoid immune rejection of transplanted human cells and to assess the effect of LDLR-deficient iHeps in an LDLR null background. Transplanted FH iHeps could repopulate 5-10% of the LRG mouse liver based on human albumin staining. Moreover, the engrafted iHeps responded to lipid-lowering drugs and recapitulated clinical observations of increased efficacy of PCSK9 antibodies compared to statins. Our human liver chimeric model could thus be useful for preclinical testing of new therapies to FH. Using the same protocol, similar human liver chimeric mice for other FH genetic variants, or mutations corresponding to other inherited liver diseases, may also be generated.

Here, we present a protocol to generate a human liver chimeric mouse model of familial hypercholesterolemia using human induced pluripotent stem cell-derived hepatocytes. This is a valuable model for testing new therapies for hypercholesterolemia.

Familial hypercholesterolemia (FH) is mostly caused by low-density lipoprotein receptor (LDLR) mutations and results in an increased risk of early-onset ...

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.