Our research was supported by grants from Instituto Nacional de Perinatolog&#237;a de M&#233;xico (21041 and 21081) and CONACYT (A1-S-8450 and&#160;252756). We thank Jessica Gonz&#225;lez Norris and Lidia Yuriria Paredes Vivas for the technical support.

This protocol was approved by the ethical committee of Instituto Nacional de Perinatolog&#237;a in Mexico City (Registry number 212250-21041). All procedures performed in these studies were in accordance with the ethical standards of the Instituto Nacional de Perinatolog&#237;a, the Helsinki Declaration, and the guidelines set forth in the Ministry of Health&#8217;s Official Mexican Standard.
1. Preparation
<ol>
	<li>Prepare a solution of 1x PBS with EDTA. To do so, add 500 &#956;L of 0.5 M EDTA stock into 500 mL of 1x PBS for a final concentration of 0.5 mM EDTA.</li>
	<li>Prepare the culture medium for HAEC. Take 450 mL of high glucose-DMEM, supplement it with 5 mL of sodium pyruvate (100 mM), 50 mL of heat-inactive fetal bovine serum qualified for stem cells, 5 mL of nonessential amino acids (100x), 5 mL of antibiotic-antimycotic (100x), 5 mL of L-glutamine (200 mM), and 500 &#956;L of mercaptoethanol (1,000x).</li>
	<li>Sterilize the containers for transporting and processing the tissue: a stainless steel container with a lid to transport the whole placenta from the operating theater to the laboratory, a tray (20 cm x 30 cm x 8 cm) to wash and remove blood from the whole placenta before the dissection of the amniotic membrane, and a plastic cutting board to separate the amniotic membrane into the three regions.</li>
	<li>Sterilize the surgical instruments (scalpels, scissors, forceps, and clamps), 500 mL beakers, cotton gauzes, and saline solution.</li>
</ol>
2. Obtaining placental tissue
NOTE: The amniotic membranes were obtained from women at full-term gestation (37&#8722;40 weeks), under indication of Cesarean delivery, without any evidence of active labor, and no microbiological characteristics of infection. The complete isolation and culture procedures were carried out within a biosecurity cabinet under sterile conditions.
<ol>
	<li>In the operating room, clamp the umbilical cord to prevent the blood flow to the rest of the tissue. Collect the entire placenta with the umbilical cord clamped in the sterile container.</li>
	<li>Add 500 mL of saline solution to the container to hydrate the placenta.</li>
	<li>Close the container and transport the tissue to the laboratory at room temperature.</li>
	<li>Put the container with the placenta inside the biosecurity cabinet. 
	NOTE: In case the dissection is not carried out within 15 min of collecting the placenta, store the container with the placenta on ice until processing. Avoid more than 1 h of elapsed time between obtaining the placenta and the start of the dissection.</li>
</ol>
3. Mechanical separation per region of the amniotic membrane
NOTE: The procedure must be carried out within a biosecurity cabinet under sterile conditions and at room temperature.
<ol>
	<li>Remove the whole placenta from the container and place it on the tray with the umbilical cord facing upward.</li>
	<li>Using a sterile cotton gauze, clean the blood clots from the surface of the chorion-amnion that covers the placenta.</li>
	<li>Identify the three regions of the membrane: the umbilical amnion enveloping the umbilical cord, the placental amnion covering the decidua basalis, and the reflected region, which is the rest of amnion that is not attached to the placenta (Figure 1).</li>
	<li>Dissect the umbilical amnion region (Figure 2A).
	<ol>
		<li>Using dissecting forceps, hold the portion of amnion membrane that covers the junction of the placenta and umbilical cord.</li>
		<li>With a scalpel, dissect the region that surrounds the cord while stretching to separate it from the chorion.</li>
		<li>Deposit the separated tissue in a labeled beaker with 100 mL of saline solution.</li>
	</ol>
	</li>
	<li>Dissect the placental amnion region (Figure 2B).
	<ol>
		<li>With a sterile cotton gauze, remove the blood clots from the surface of the chorion-amnion that covers the placenta.</li>
		<li>Hold the membrane on the border between the placenta and the reflected region with dissecting forceps.</li>
		<li>Cut along the circumference of the placenta with the scalpel.</li>
		<li>Separate the placental amnion from the chorion, being careful not to cut any vessels from the placenta.</li>
		<li>Place the separated tissue in another labeled beaker with 300 mL of saline solution.</li>
	</ol>
	</li>
	<li>Separate the rest of the amniotic membrane that is not attached to the placenta (i.e., the reflected portion) from the chorion (Figure 2C).
	<ol>
		<li>Collect the reflected region in another labeled beaker with 300 mL of saline solution. 
		NOTE: Add saline solution continually during the dissection to prevent tissue from drying out.</li>
	</ol>
	</li>
</ol>
4. Washing the membranes
NOTE: The procedure must be carried out within a biosecurity cabinet under sterile conditions at room temperature.
<ol>
	<li>Discard the saline solution of each membrane region separately.</li>
	<li>Add 100 mL of fresh saline solution to the umbilical region.</li>
	<li>Add 300 mL of fresh saline solution to the placental and reflected regions respectively.</li>
	<li>Stir&#160;the membranes with the help of dissecting forceps to remove blood residue.</li>
	<li>Discard the saline solution.</li>
	<li>Repeat the washes and agitation at least 3x until the membranes are translucent.</li>
	<li>Place and extend the membranes on the board to clean with sterile gauze the blood clots that were not removed with the washes. 
	NOTE: It is very important to remove as many erythrocytes as possible, as their presence affects the trypsin function and the viability of subsequent cell cultures.</li>
</ol>
5. Enzymatic digestion of the membranes from different regions
NOTE: The procedure must be carried out within a biosecurity cabinet under sterile conditions.
<ol>
	<li>Cut the reflected and placental regions into two or three fragments.</li>
	<li>Do not cut the umbilical region.</li>
	<li>Place the fragments of each region in centrifuge tubes. Add 20 mL of 0.5% trypsin/EDTA to the reflected and placental regions and 5 mL of 0.5% trypsin/EDTA to the umbilical region, respectively. 
	NOTE: It is important to cut the reflected and placental regions into smaller pieces because they need to be completely immersed in the trypsin solution.</li>
	<li>Shake the centrifuge tubes lightly for 30 s. Discard the trypsin.</li>
	<li>Add 30 mL of new 0.5% trypsin/EDTA to the reflected and placental regions and 15 mL of new 0.5% trypsin/EDTA to the umbilical region, respectively.</li>
	<li>Place the tubes in a rotator inside the incubator.</li>
	<li>Incubate with rotation (20 rpm) for 40 min at 37 &#176;C. 
	NOTE: If a tube rotator is not available, shake the tubes lightly manually every 10 min.</li>
	<li>Transfer the trypsin/cell solutions from each region into new centrifuge tubes.</li>
	<li>Add 2x the volume of HAEC media prewarmed at 37 &#176;C per tube to inactivate the enzyme.</li>
	<li>Store the first digestion on ice.</li>
	<li>Repeat steps 5.6&#8722;5.8 for a second digestion period.</li>
	<li>For each region, hold one end of the amnion portion using dissecting forceps, and with another pair squeeze along the tissue to remove rows of epithelial cells that did not completely peel off during previous incubation periods.</li>
	<li>Collect the second digestion into another set of centrifuge tubes and inactivate with 2x the volume of HAEC media.</li>
	<li>Discard the digested membranes into a biohazard container.</li>
</ol>
6. Isolation of the HAEC
NOTE: The procedure must be carried out within a biosecurity cabinet under sterile conditions.
<ol>
	<li>Centrifuge all tubes at 200 x g for 10 min at 4 &#176;C.</li>
	<li>Discard the supernatant and add 10 mL of prewarmed HAEC media (to 37 &#176;C) per tube and pipet gently to disaggregate each pellet.</li>
	<li>Combine the cellular suspensions of the two digestions in an individual tube for each membrane region.</li>
	<li>Filter the cellular suspensions using 100 &#956;m cell strainers to remove the extracellular matrix debris and obtain single cells.</li>
	<li>Prepare three aliquots with 90 &#181;L of trypan blue in a microcentrifuge tube.</li>
	<li>Add 10 &#956;L of each cell suspension per membrane region into the microcentrifuge tubes and mix.</li>
	<li>Count the cells with a hemocytometer under a light field microscope.</li>
</ol>
7. Culture of HAEC
<ol>
	<li>Seed the HAEC from the three regions separately at a density of 3 &#215; 104 cells/cm2 with prewarmed HAEC media, supplemented with 10 ng/mL of human epidermal growth factor (EGF).
	<ol>
		<li>Seed the cells in 100 mm plates to maintain them in vitro or in 24 well plates for immunochemical analysis.</li>
	</ol>
	</li>
	<li>Incubate the dishes at 37 &#176;C under normoxic conditions (5% CO2) in a humidified incubator.</li>
	<li>Add EGF daily and change the medium every third day. 
	NOTE: The cells will become confluent after 4&#8722;6 days.</li>
	<li>Use the cells for conventional immunohistochemistry, cell sorting analysis, cryopreserving, RNA and protein extraction, or to continue the passage.</li>
</ol>
8. Passage of HAEC
<ol>
	<li>Remove the HAEC medium and wash 2x with PBS/EDTA 0.01M solution.</li>
	<li>Incubate with a PBS/EDTA 0.01M solution for 15 min at 37 &#176;C.</li>
	<li>Remove the PBS/EDTA and add 1.5 mL of 0.5% trypsin/EDTA.</li>
	<li>Incubate for 5&#8722;8 min at 37 &#176;C.</li>
	<li>Inactivate the enzyme with two volumes of HAEC media.</li>
	<li>Collect the mixed solution and centrifuge for 5 min at 200 x g.</li>
	<li>Count the cells and continue with following passages or use the cells for further analysis.</li>
</ol>

<ol>
	<li>Shahbazi, M. N., 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=Self-organization+of+the+human+embryo+in+the+absence+of+maternal+tissues.">Self-organization of the human embryo in the absence of maternal tissues.</a> Nature Cell Biology. 18 (6), 700-708 (2016).</li><li>Garcia-Lopez, 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=Human+amniotic+epithelium+(HAE)+as+a+possible+source+of+stem+cells+(SC).">Human amniotic epithelium (HAE) as a possible source of stem cells (SC).</a> Gaceta Medica de Mexico. 151 (1), 66-74 (2015).</li><li>Gramignoli, R., Srinivasan, R. C., Kannisto, K., Strom, S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+Human+Amnion+Epithelial+Cells+According+to+Current+Good+Manufacturing+Procedures.">Isolation of Human Amnion Epithelial Cells According to Current Good Manufacturing Procedures.</a> Current Protocols in Stem Cell Biology. 37, (2016).</li><li>Murphy, 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=Amnion+epithelial+cell+isolation+and+characterization+for+clinical+use.">Amnion epithelial cell isolation and characterization for clinical use.</a> Current Protocols in Stem Cell Biology. , (2010).</li><li>Garcia-Castro, I. 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=Markers+of+Pluripotency+in+Human+Amniotic+Epithelial+Cells+and+Their+Differentiation+to+Progenitor+of+Cortical+Neurons.">Markers of Pluripotency in Human Amniotic Epithelial Cells and Their Differentiation to Progenitor of Cortical Neurons.</a> PLoS One. 10 (12), 0146082 (2015).</li><li>Garcia-Lopez, 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=Pluripotency+markers+in+tissue+and+cultivated+cells+in+vitro+of+different+regions+of+human+amniotic+epithelium.">Pluripotency markers in tissue and cultivated cells in vitro of different regions of human amniotic epithelium.</a> Experimental Cell Research. 375 (1), 31-41 (2019).</li><li>Yang, P. 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=Biological+characterization+of+human+amniotic+epithelial+cells+in+a+serum-free+system+and+their+safety+evaluation.">Biological characterization of human amniotic epithelial cells in a serum-free system and their safety evaluation.</a> Acta Pharmacological Sinica. 39 (8), 1305-1316 (2018).</li><li>Zou, 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=MicroRNA32+silences+WWP2+expression+to+maintain+the+pluripotency+of+human+amniotic+epithelial+stem+cells+and+beta+isletlike+cell+differentiation.">MicroRNA32 silences WWP2 expression to maintain the pluripotency of human amniotic epithelial stem cells and beta isletlike cell differentiation.</a> International Journal of Molecular Medicine. 41 (4), 1983-1991 (2018).</li><li>Avila-Gonzalez, 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=Capturing+the+ephemeral+human+pluripotent+state.">Capturing the ephemeral human pluripotent state.</a> Developmental Dynamics. 245 (7), 762-773 (2016).</li><li>Niknejad, 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=Properties+of+the+amniotic+membrane+for+potential+use+in+tissue+engineering.">Properties of the amniotic membrane for potential use in tissue engineering.</a> European Cells &amp; Materials. 15, 88-99 (2008).</li><li>Miki, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stem+cell+characteristics+and+the+therapeutic+potential+of+amniotic+epithelial+cells.">Stem cell characteristics and the therapeutic potential of amniotic epithelial cells.</a> American Journal of Reproductive Immunology. 80 (4), 13003 (2018).</li><li>Wu, Q., 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=Comparison+of+the+proliferation,+migration+and+angiogenic+properties+of+human+amniotic+epithelial+and+mesenchymal+stem+cells+and+their+effects+on+endothelial+cells.">Comparison of the proliferation, migration and angiogenic properties of human amniotic epithelial and mesenchymal stem cells and their effects on endothelial cells.</a> International Journal of Molecular Medicine. 39 (4), 918-926 (2017).</li><li>Hammer, 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=Amnion+epithelial+cells,+in+contrast+to+trophoblast+cells,+express+all+classical+HLA+class+I+molecules+together+with+HLA-G.">Amnion epithelial cells, in contrast to trophoblast cells, express all classical HLA class I molecules together with HLA-G.</a> American Journal of Reproductive Immunology. 37 (2), 161-171 (1997).</li><li>Benirschke, 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=Anatomy+and+Pathology+of+the+Placental+Membranes.">Anatomy and Pathology of the Placental Membranes.</a> Pathology of the Human Placenta. , 268-318 (1995).</li><li>Banerjee, 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=Different+metabolic+activity+in+placental+and+reflected+regions+of+the+human+amniotic+membrane.">Different metabolic activity in placental and reflected regions of the human amniotic membrane.</a> Placenta. 36 (11), 1329-1332 (2015).</li><li>Kim, S. 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=miR-143+regulation+of+prostaglandin-endoperoxidase+synthase+2+in+the+amnion:+implications+for+human+parturition+at+term.">miR-143 regulation of prostaglandin-endoperoxidase synthase 2 in the amnion: implications for human parturition at term.</a> PLoS One. 6 (9), 24131 (2011).</li><li>Han, Y. 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=Region-specific+gene+expression+profiling:+novel+evidence+for+biological+heterogeneity+of+the+human+amnion.">Region-specific gene expression profiling: novel evidence for biological heterogeneity of the human amnion.</a> Biology of Reproduction. 79 (5), 954-961 (2008).</li><li>Alcaraz, 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=Autocrine+TGF-beta+induces+epithelial+to+mesenchymal+transition+in+human+amniotic+epithelial+cells.">Autocrine TGF-beta induces epithelial to mesenchymal transition in human amniotic epithelial cells.</a> Cell Transplantation. 22 (8), 1351-1367 (2013).</li><li>Canciello, 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=Progesterone+prevents+epithelial-mesenchymal+transition+of+ovine+amniotic+epithelial+cells+and+enhances+their+immunomodulatory+properties.">Progesterone prevents epithelial-mesenchymal transition of ovine amniotic epithelial cells and enhances their immunomodulatory properties.</a> Scientific Reports. 7 (1), 3761 (2017).</li><li>Canciello, A., Greco, L., Russo, V., Barboni, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amniotic+Epithelial+Cell+Culture.">Amniotic Epithelial Cell Culture.</a> Methods in Molecular Biology. 1817, 67-78 (2018).</li><li>Singh, A. 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=Signaling+network+crosstalk+in+human+pluripotent+cells:+a+Smad2/3-regulated+switch+that+controls+the+balance+between+self-renewal+and+differentiation.">Signaling network crosstalk in human pluripotent cells: a Smad2/3-regulated switch that controls the balance between self-renewal and differentiation.</a> Cell Stem Cell. 10 (3), 312-326 (2012).</li><li>Villa-Diaz, L. G., Kim, J. K., Laperle, A., Palecek, S. P., Krebsbach, P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inhibition+of+Focal+Adhesion+Kinase+Signaling+by+Integrin+alpha6beta1+Supports+Human+Pluripotent+Stem+Cell+Self-Renewal.">Inhibition of Focal Adhesion Kinase Signaling by Integrin alpha6beta1 Supports Human Pluripotent Stem Cell Self-Renewal.</a> Stem Cells. 34 (7), 1753-1764 (2016).</li><li>Bednar, A. D., Beardall, M. K., Brace, R. A., Cheung, C. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+expression+and+regional+distribution+of+aquaporins+in+amnion+of+normal+and+gestational+diabetic+pregnancies.">Differential expression and regional distribution of aquaporins in amnion of normal and gestational diabetic pregnancies.</a> Physiological Reports. 3 (3), 12320 (2015).</li><li>Avila-Gonzalez, 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=Human+amniotic+epithelial+cells+as+feeder+layer+to+derive+and+maintain+human+embryonic+stem+cells+from+poor-quality+embryos.">Human amniotic epithelial cells as feeder layer to derive and maintain human embryonic stem cells from poor-quality embryos.</a> Stem Cell Research. 15 (2), 322-324 (2015).</li></ol>

The authors have nothing to disclose.

We implemented a new protocol to isolate HAEC from term membranes. It differs from previous reports in that each membrane was divided into its three anatomical regions prior to isolation to analyze cells from each one.
One of the most critical steps in the protocol is the washing of the membrane to remove all blood clots, because they can interfere with the activity of trypsin when separating the epithelial cells. Failure to carry out this step properly can lead to obtaining a primary culture ...

Human amniotic epithelium&#160;cells&#160;(HAEC) originate during the early stages of embryonic development, at around eight days postfertilization. They arise from a population of squamous epithelial cells of the epiblast that derive from the innermost layer of the amniotic membrane1. Thus, HAEC are considered&#160;remnants of pluripotent cells from the epiblast that have the potential to differentiate into the three germ layers of the embryo2. In the last decade, diverse&#160;research groups have developed methods to isolate&#160;these cells from the amniotic membrane at the term of gestation to characterize their presumptive pluripotency-related properties in a culture model&#160;in vitro3,4.&#160;
Accordingly, it&#160;has been found that HAEC feature traits characteristic of human pluripotent stem cells (HPSC), such as the surface antigens SSEA-3, SSEA-4, TRA 1-60, TRA 1-81; the core of pluripotency transcription factors OCT4, SOX2, and NANOG; and the proliferation marker KI67, suggesting that they are self-renewing5,6,7. Moreover, these cells have been challenged using differentiation protocols to obtain cells positive for lineage-specific markers of the three germ layers (ectoderm, mesoderm, and endoderm)4,5,8, as well as in animal models of human diseases. Finally, HAEC express E-cadherin, which demonstrate that they retain an epithelial nature much like the HPSC5,9.
Apart from their embryonic origin, HAEC have other intrinsic properties that make them suitable for different clinical applications, such as the secretion of anti-inflammatory and antibacterial molecules10,11, growth factors and cytokine release12, no formation of teratomas when they are transplanted into immunodeficient mice in contrast with HPSC2, and immunological tolerance because they express HLA-G, which decreases the risk of rejection after transplantation13.
However, previous reports have assumed that the human amnion is a homogenous membrane, without considering that it can be anatomically and physiologically divided into three regions: placental (the amnion that covers the decidua basalis), umbilical (the part that envelops the umbilical cord), and reflected (the rest of the membrane not attached to the placenta)14. It has been shown that the placental and reflected regions of the amnion display differences in morphology, mitochondrial activity, detection of reactive oxygen species15, miRNA expression16, and activation of signaling pathways17. These results suggest that the human amnion is integrated by a heterogeneous population with different functionality that should be considered for further studies carried out in either in situ or in vitro models. While other laboratories have designed protocols for the isolation of HAEC from the whole membrane, our laboratory has established a protocol to isolate, culture, and characterize cells from different anatomical regions.

<table>
	<tbody>
		<tr>
			<td>Culture reagents</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>2-Mercaptoethanol</td>
			<td>Thermo Fisher Scientific/Gibco</td>
			<td>21985023</td>
			<td>55 mM</td>
		</tr>
		<tr>
			<td>Animal-Free Recombinant Human EGF</td>
			<td>Peprotech</td>
			<td>AF-100-15</td>
			<td></td>
		</tr>
		<tr>
			<td>Antibiotic-Antimycotic</td>
			<td>Thermo Fisher Scientific/Gibco</td>
			<td>15240062</td>
			<td>100X</td>
		</tr>
		<tr>
			<td>Dulbecco&#39;s Modified Eagle Medium</td>
			<td>Thermo Fisher Scientific/Gibco</td>
			<td>12430054</td>
			<td>Supplemented with high glucose and HEPES</td>
		</tr>
		<tr>
			<td>EDTA</td>
			<td>Thermo Fisher Scientific/Ambion</td>
			<td>AM9260G</td>
			<td>0.5 M</td>
		</tr>
		<tr>
			<td>Embryonic stem-cell FBS, qualified</td>
			<td>Thermo Fisher Scientific/Gibco</td>
			<td>10439024</td>
			<td></td>
		</tr>
		<tr>
			<td>Non-Essential Amino Acids</td>
			<td>Thermo Fisher Scientific/Gibco</td>
			<td>11140050</td>
			<td>100X</td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>any brand</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate-Buffered Saline</td>
			<td>Thermo Fisher Scientific/Gibco</td>
			<td>10010023</td>
			<td>1X</td>
		</tr>
		<tr>
			<td>Saline solution (sodium chloride 0.9%)</td>
			<td>any brand</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Pyruvate</td>
			<td>Thermo Fisher Scientific/Gibco</td>
			<td>11360070</td>
			<td>100 mM</td>
		</tr>
		<tr>
			<td>Trypsin/EDTA 0.05%</td>
			<td>Thermo Fisher Scientific/Gibco</td>
			<td>25300054</td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable material</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>100 &#181;m Cell Strainer</td>
			<td>Corning/Falcon</td>
			<td>352360</td>
			<td></td>
		</tr>
		<tr>
			<td>100 mm TC-Treated Culture Dish</td>
			<td>Corning</td>
			<td>430167</td>
			<td></td>
		</tr>
		<tr>
			<td>24-well Clear TC-treated Multiple Well Plates</td>
			<td>Corning/Costar</td>
			<td>3526</td>
			<td></td>
		</tr>
		<tr>
			<td>6-well Clear TC-treated Multiple Well Plates</td>
			<td>Corning/Costar</td>
			<td>3516</td>
			<td></td>
		</tr>
		<tr>
			<td>Non-Pyrogenic Sterile Centrifuge Tube</td>
			<td>any brand</td>
			<td></td>
			<td>with conical bottom</td>
		</tr>
		<tr>
			<td>Non-Pyrogenic sterile tips of 1,000 &#181;l, 200 &#181;l and 10 &#181;l.</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile cotton gauzes</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile serological pipettes of 5, 10 and 25 mL</td>
			<td>any brand</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile surgical gloves</td>
			<td>any brand</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Biological safety cabinet</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Micropipettes</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Motorized Pipet Filler/Dispenser</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile beakers of 500 mL</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile plastic cutting board</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile scalpels, scissors, forceps, clamps</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile stainless steel container</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile tray</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Tube Rotator</td>
			<td>MaCSmix</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Antibodies and Kits</td>
			<td></td>
			<td></td>
			<td>Antibody ID</td>
		</tr>
		<tr>
			<td>Anti-E-cadherin</td>
			<td>BD Biosciences</td>
			<td>610181</td>
			<td>RRID:AB_3975</td>
		</tr>
		<tr>
			<td>Anti-KI67</td>
			<td>Santa Cruz</td>
			<td>23900</td>
			<td>RRID:AB_627859)</td>
		</tr>
		<tr>
			<td>Anti-NANOG</td>
			<td>Peprotech</td>
			<td>500-P236</td>
			<td>RRID:AB_1268274</td>
		</tr>
		<tr>
			<td>Anti-OCT4</td>
			<td>Abcam</td>
			<td>ab19857</td>
			<td>RRID:AB_44517</td>
		</tr>
		<tr>
			<td>Anti-SOX2</td>
			<td>Millipore</td>
			<td>AB5603</td>
			<td>RRID:AB_2286686</td>
		</tr>
		<tr>
			<td>Anti-SSEA-4</td>
			<td>Cell Signaling</td>
			<td>4755</td>
			<td>RRID:AB_1264259</td>
		</tr>
		<tr>
			<td>Anti-TRA-1-60</td>
			<td>Cell Signaling</td>
			<td>4746</td>
			<td>RRID:AB_2119059</td>
		</tr>
		<tr>
			<td>Goat Anti-Mouse Alexa Fluor 488</td>
			<td>Thermo Fisher Scientific</td>
			<td>A-11029</td>
			<td>RRID:AB_2534088</td>
		</tr>
		<tr>
			<td>Goat Anti-Rabbit Alexa Fluor 568</td>
			<td>Thermo Fisher Scientific</td>
			<td>A-11036</td>
			<td>RRID:AB_10563566</td>
		</tr>
		<tr>
			<td>Tunel Assay Kit</td>
			<td>Abcam</td>
			<td>66110</td>
			<td></td>
		</tr>
	</tbody>
</table>

in vitro culture of epithelial cells from different anatomical regions of the human amniotic membrane

Several protocols have been reported in the literature for the isolation and culture of human amniotic epithelial cells (HAEC). However, these assume that the amniotic epithelium is a homogeneous layer. The human amnion can be divided into three anatomical regions: reflected, placental, and umbilical. Each region has different physiological roles, such as in pathological conditions. Here, we describe a protocol to dissect human amnion tissue in three sections and maintain it in vitro. In culture, cells derived from the reflected amnion displayed a cuboidal morphology, while cells from both placental and umbilical regions were squamous. Nonetheless, all the cells obtained have an epithelial phenotype, demonstrated by the immunodetection of E-cadherin. Thus, because the placental and reflected regions in situ differ in cellular components and molecular functions, it may be necessary for in vitro studies to consider these differences, because they could have physiological implications for the use of HAEC in biomedical research and the promising application of these cells in regenerative medicine.

HAEC were isolated from each of the three anatomical regions of the amniotic membrane and individually cultured in vitro. After 48 h of culture, cells with an epithelial phenotype adhered to the surface of the plate, although the media also contained cell debris and floating cells, which were removed once the medium was changed (Figure 3).
During the processing of primary culture (passage zero, P0), some complications could arise that can interfere with the experi...

Watch this Scientific Journal Video about In Vitro Culture of Epithelial Cells from Different Anatomical Regions of the Human Amniotic Membrane at JoVE.com

In Vitro Culture of Epithelial Cells from Different Anatomical Regions of the Human Amniotic Membrane

This protocol describes the isolation of epithelial cells from different anatomical regions of the human amniotic membrane to determine their heterogeneity and functional properties for possible application in clinical and physiopathological models.

Several protocols have been reported in the literature for the isolation and culture of human amniotic epithelial cells (HAEC). However, these assume that ...

in-vitro-culture-epithelial-cells-from-different-anatomical-regions

Research

JoVE Journal

Developmental Biology

7.7K Views.  Instituto Nacional de Perinatología. This protocol describes the isolation of epithelial cells from different anatomical regions of the human amniotic membrane to determine their heterogeneity and functional properties for possible application in clinical and physiopathological models.

Video: In Vitro Culture of Epithelial Cells from Different Anatomical Regions of the Human Amniotic Membrane

Primary Endodermal Epithelial Cell Culture from the Yolk Sac Membrane of Japanese Quail Embryos

We established an endodermal epithelial cell culture model (EEC) for studying the function of certain enzymes and proteins in mediating nutrient utilization by avian embryos during development. Fertilized Japanese quail eggs were incubated at 37 &#176;C for 5 days and then yolk sac membranes (YSM) were collected to establish the EEC culture system. We isolated the embryonic endoderm layer from YSM, and sliced the membrane into 2 - 3 mm pieces and partially digested with collagenase before seeding in 24-well culture plates. The EECs proliferate out of the tissue and are ready for cell culture studies. We found that the EECs had typical characteristics of YSM in vivo, for example, accumulation of lipid droplets, expression of sterol O-acyltransferase and lipoprotein lipase. The partial digestion treatment significantly increased the successful rate of EEC culture. Utilizing the EECs, we demonstrated that the expression of SOAT1 was regulated by the cAMP dependent protein kinase A related pathway. This primary Japanese quail EEC culture system is a useful tool to study embryonic lipid transportation and to clarify the role of genes involved in mediating nutrient utilization in YSM during avian embryonic development.

To study the mechanism of lipid utilization in yolk sac membranes during the late stages of avian embryonic development, we established a primary Japanese quail embryonic endodermal epithelial cell culture system.

We established an endodermal epithelial cell culture model (EEC) for studying the function of certain enzymes and proteins in mediating nutrient ...

Development of an In Vitro Assay to Evaluate Contractile Function of Mesenchymal Cells that Underwent Epithelial-Mesenchymal Transition

Fibrosis is often involved in the pathogenesis of various chronic progressive diseases such as interstitial pulmonary disease. Pathological hallmark is the formation of fibroblastic foci, which is associated with the disease severity. Mesenchymal cells consisting of the fibroblastic foci are proposed to be derived from several cell sources, including originally resident intrapulmonary fibroblasts and circulating fibrocytes from bone marrow. Recently, mesenchymal cells that underwent epithelial-mesenchymal transition (EMT) have been also supposed to contribute to the pathogenesis of fibrosis. In addition, EMT can be induced by transforming growth factor &#946;, and EMT can be enhanced by pro-inflammatory cytokines like tumor necrosis factor &#945;. The gel contraction assay is an ideal in vitro model for the evaluation of contractility, which is one of the characteristic functions of fibroblasts and contributes to wound repair and fibrosis. Here, the development of a gel contraction assay is demonstrated for evaluating contractile ability of mesenchymal cells that underwent EMT.

Development of an In Vitro Assay to Evaluate Contractile Function of Mesenchymal Cells that Underwent Epithelial-Mesenchymal Transition

Here, we describe the development and application of a gel contraction assay for evaluating contractile function in mesenchymal cells that underwent epithelial-mesenchymal transition.

Fibrosis is often involved in the pathogenesis of various chronic progressive diseases such as interstitial pulmonary disease. Pathological hallmark is ...

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 ...

The Production of Pluripotent Stem Cells from Mouse Amniotic Fluid Cells Using a Transposon System

Induced pluripotent stem (iPS) cells are generated from mouse and human somatic cells by forced expression of defined transcription factors using different methods. Here, we produced iPS cells from mouse amniotic fluid cells, using a non-viral-based transposon system. All obtained iPS cell lines exhibited characteristics of pluripotent cells, including the ability to differentiate toward derivatives of all three germ layers in vitro and in vivo. This strategy opens up the possibility of using cells from diseased fetuses to develop new therapies for birth defects.

In this study, we generate induced pluripotent stem cells from mouse amniotic fluid cells, using a non-viral-based transposon system.

Induced pluripotent stem (iPS) cells are generated from mouse and human somatic cells by forced expression of defined transcription factors using ...

Isolation of Mouse Endometrial Epithelial and Stromal Cells for In Vitro Decidualization

Decidualization is a progesterone-dependent differentiation process of endometrial stromal cells and is a prerequisite for successful embryo implantation. Although many efforts have been made to reveal the underlying mechanisms of decidualization, the exact signaling between the epithelial cells that are in contact with the embryo and the underlying stromal cells remains poorly understood. Therefore, studying decidualization in a way that takes both the epithelial and stromal cells into account could improve our knowledge about the molecular details of decidualization. For this purpose, in vivo models of artificial decidualization are physiologically the most relevant; however, manipulation of intercellular communication is limited. Currently, in vitro cultures of endometrial stromal cells are being used to investigate the modulation of decidualization by several signaling molecules. Conventionally, human or mouse endometrial stromal cells are used. However, the availability of human samples is very often limited. Furthermore, the use of murine tissues is accompanied with variety in the method of culturing. This study presents a validated and standardized method to obtain pure Endometrial Epithelial Cell (EEC) and Stromal Cell (ESC) cultures using adult intact mice treated with estrogen for three consecutive days. The protocol is optimized to improve the yield, viability, and purity of the cells and was further extended in order to study decidualization in a coculture of EEC and ESC. This model may be suitable to exploit the importance of both cell types in decidualization and to evaluate the contribution of significant signaling molecules secreted by EEC or ESC during the intercellular communication.

Isolation of Mouse Endometrial Epithelial and Stromal Cells for In Vitro Decidualization

This study presents a standardized and validated method for the isolation and culture of primary mouse endometrial stromal and epithelial cells, which can be used in a coculture system to study in vitro decidualization.

Decidualization is a progesterone-dependent differentiation process of endometrial stromal cells and is a prerequisite for successful embryo implantation. ...

Directed Differentiation of Primitive and Definitive Hematopoietic Progenitors from Human Pluripotent Stem Cells

One of the major goals for regenerative medicine is the generation and maintenance of hematopoietic stem cells (HSCs) derived from human pluripotent stem cells (hPSCs). Until recently, efforts to differentiate hPSCs into HSCs have predominantly generated hematopoietic progenitors that lack HSC potential, and instead resemble yolk sac hematopoiesis.&#160;These resulting hematopoietic progenitors may have limited utility for in vitro disease modeling of various adult hematopoietic disorders, particularly those of the lymphoid lineages. However, we have recently described methods to generate erythro-myelo-lymphoid multilineage definitive hematopoietic progenitors from hPSCs using a stage-specific directed differentiation protocol, which we outline here. Through enzymatic dissociation of hPSCs on basement membrane matrix-coated plasticware, embryoid bodies (EBs) are formed. EBs are differentiated to mesoderm by recombinant BMP4, which is subsequently specified to the definitive hematopoietic program by the GSK3&#946; inhibitor, CHIR99021. Alternatively, primitive hematopoiesis is specified by the PORCN inhibitor, IWP2. Hematopoiesis is further driven through the addition of recombinant VEGF and supportive hematopoietic cytokines. The resulting hematopoietic progenitors generated using this method have the potential to be used for disease and developmental modeling, in vitro.

Here, we present human pluripotent stem cell (hPSC) culture protocols, used to differentiate hPSCs into CD34+ hematopoietic progenitors. This method uses stage-specific manipulation of canonical WNT signaling to specify cells exclusively to either the definitive or primitive hematopoietic program.

One of the major goals for regenerative medicine is the generation and maintenance of hematopoietic stem cells (HSCs) derived from human pluripotent stem ...

Reprogramming Primary Amniotic Fluid and Membrane Cells to Pluripotency in Xeno-free Conditions

Autologous cell-based therapies got a step closer to reality with the introduction of induced pluripotent stem cells. Fetal stem cells, such as amniotic fluid and membrane mesenchymal stem cells, represent a unique type of undifferentiated cells with promise in tissue engineering and for reprogramming into iPSC for future pediatric interventions and stem cell banking. The protocol presented here describes an optimized procedure for extracting and culturing primary amniotic fluid and membrane mesenchymal stem cells and generating episomal induced pluripotent stem cells from these cells in fully chemically defined culture conditions utilizing human recombinant vitronectin and the E8 medium. Characterization of the new lines by applying stringent methods &#8211; flow cytometry, confocal imaging, teratoma formation and transcriptional profiling &#8211; is also described. The newly generated lines express markers of embryonic stem cells &#8211; Oct3/4A, Nanog, Sox2, TRA-1-60, TRA-1-81, SSEA-4 &#8211; while being negative for the SSEA-1 marker. The stem cell lines form teratomas in scid-beige mice in 6-8 weeks and the teratomas contain tissues representative of all three germ layers. Transcriptional profiling of the lines by submitting global expression microarray data to a bioinformatic pluripotency assessment algorithm deemed all lines pluripotent and therefore, this approach is an attractive alternative to animal testing. The new iPSC lines can readily be used in downstream experiments involving the optimization of differentiation and tissue engineering.

This protocol describes the reprogramming of primary amniotic fluid and membrane mesenchymal stem cells into induced pluripotent stem cells using a non-integrating episomal approach in fully chemically defined conditions. Procedures of extraction, culture, reprogramming, and characterization of the resulting induced pluripotent stem cells by stringent methods are detailed.

Autologous cell-based therapies got a step closer to reality with the introduction of induced pluripotent stem cells. Fetal stem cells, such as amniotic ...

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 ...

Application of Aorta-gonad-mesonephros Explant Culture System in Developmental Hematopoiesis

The limitation of using mouse embryos for hematopoiesis studies is the added inconvenience in operations, which is largely due to the intrauterine development of the embryo. Although genetic data from knockout (KO) mice are convincing, it is not realistic to generate KO mice for all genes as needed. In addition, performing in vivo rescue experiments to consolidate the data obtained from KO mice is not convenient. To overcome these limitations, the Aorta-Gonad-Mesonephros (AGM) explant culture was developed as an appropriate system to study hematopoietic stem cell (HSC) development. Especially for rescue experiments, it can be used to recover the impaired hematopoiesis in KO mice. By adding the appropriate chemicals into the medium, the impaired signaling can be reactivated or up-regulated pathways can be inhibited. With the use of this method, many experiments can be performed to identify the critical regulators of HSC development, including HSC related gene expression at mRNA and protein levels, colony formation ability, and reconstitution capacity. This series of experiments would be helpful in defining the underlying mechanisms essential for HSC development in mammals.

This protocol describes using cultured Aorta-Gonad-Mesonephros for expression analyses, colony-forming units in the culture and spleen, and long-term reconstitution to determine the effect of regulatory factors and signaling pathways on hematopoietic stem cell development. This has been demonstrated as an effective system for studying hematopoietic stem cell biology and function.

The limitation of using mouse embryos for hematopoiesis studies is the added inconvenience in operations, which is largely due to the intrauterine ...

Culturing of Retinal Pigment Epithelial Cells on an Ex Vivo Model of Aged Human Bruch's Membrane

Aside from vitamins and antioxidants recommended by the Age-Related Eye Disease Study, there is no effective therapy for &#34;dry,&#34;&#160;or atrophic age-related macular degeneration (AMD) which represents 90% of the cases. Therapies are needed to slow or retard the development of geographic atrophy (GA), and understanding Bruch&#39;s membrane pathology is part of this process. Alterations in human Bruch&#39;s membrane precede the progression of AMD by contributing to the damage of retinal pigment epithelial (RPE) cells. Given the lack of sufficient animal models to study AMD, ex vivo models of aged human Bruch&#39;s membrane serve as a useful tool to study the behavior of RPE cells from immortalized and primary cell lines as well as RPE lines derived from induced pluripotent stem cells (iPSCs). Here, we present a detailed method that allows one to determine the effects of RPE cell behavior seeded on harvested human Bruch&#39;s membrane explants from human donors, including attachment, apoptosis and proliferation, ability to phagocytize photoreceptor outer segments, establishment of polarity, and gene expression. This assay provides an ex vivo model of aged Bruch&#39;s membrane to assess the functional characteristics of RPE cells when seeded on aged/compromised extracellular matrix.

Culturing of Retinal Pigment Epithelial Cells on an Ex Vivo Model of Aged Human Bruch&#039;s Membrane

The goal of this protocol is to demonstrate the culturing of retinal pigment epithelial (RPE) cells on aged and/or diseased human Bruch&#39;s membrane. This method is suitable to study RPE cell behavior on a compromised extracellular matrix.

Aside from vitamins and antioxidants recommended by the Age-Related Eye Disease Study, there is no effective therapy for &#34;dry,&#34;&#160;or atrophic ...