This work was supported by the National Natural Science Foundation of China (No. 81870432 and 81570567 to X.L.Z.), (No. 81571994 to P.N.S.); the Natural Science Foundation of Guangdong Province, China (No. 2020A1515010054 to P.N.S.), The Li Ka Shing Shantou University Foundation (No. L1111 2008 to P.N.S.). We would like to thank Prof. Stanley Lin from Shantou University Medical College for useful advice.

1. Stem cell maintenance
NOTE: The cell maintenance protocol described below applies to the hES03 cell line maintained in an adherent monolayer. For all the following protocols in this manuscript, cells should be handled under a biological safety cabinet.
<ol>
	<li>Prepare 1x mTesR stem cell culture medium by diluting 5x supplementary medium to mTesR basic medium.</li>
	<li>Prepare 30x hESC-qualified Matrigel medium by diluting 5 mL of hESC-qualified Matrigel with 5 mL of DMEM/F12 on the ice...

<ol>
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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=PI3K/mTORC2+regulates+TGF-beta/Activin+signalling+by+modulating+Smad2/3+activity+via+linker+phosphorylation.">PI3K/mTORC2 regulates TGF-beta/Activin signalling by modulating Smad2/3 activity via linker phosphorylation.</a> Nature Communications. 6, 7212 (2015).</li><li>Borowiak, 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=Small+molecules+efficiently+direct+endodermal+differentiation+of+mouse+and+human+embryonic+stem+cells.">Small molecules efficiently direct endodermal differentiation of mouse and human embryonic stem cells.</a> Cell Stem Cell. 4, 348-358 (2009).</li><li>Tahamtani, 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=Treatment+of+human+embryonic+stem+cells+with+different+combinations+of+priming+and+inducing+factors+toward+definitive+endoderm.">Treatment of human embryonic stem cells with different combinations of priming and inducing factors toward definitive endoderm.</a> Stem Cells and Development. 22, 1419-1432 (2013).</li><li>Song, Z., 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=Efficient+generation+of+hepatocyte-like+cells+from+human+induced+pluripotent+stem+cells.">Efficient generation of hepatocyte-like cells from human induced pluripotent stem cells.</a> Cell Research. 19, 1233-1242 (2009).</li><li>Sullivan, G. 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=Generation+of+functional+human+hepatic+endoderm+from+human+induced+pluripotent+stem+cells.">Generation of functional human hepatic endoderm from human induced pluripotent stem cells.</a> Hepatology. 51, 329-335 (2010).</li><li>Xia, 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+stem+cell-derived+hepatocytes+as+a+model+for+hepatitis+B+virus+infection,+spreading+and+virus-host+interactions.">Human stem cell-derived hepatocytes as a model for hepatitis B virus infection, spreading and virus-host interactions.</a> Journal of Hepatology. 66, 494-503 (2017).</li><li>Li, 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=Derivation+and+applications+of+human+hepatocyte-like+cells.">Derivation and applications of human hepatocyte-like cells.</a> World Journal of Stem Cells. 11, 535-547 (2019).</li><li>Ogawa, 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=Three-dimensional+culture+and+cAMP+signaling+promote+the+maturation+of+human+pluripotent+stem+cell-derived+hepatocytes.">Three-dimensional culture and cAMP signaling promote the maturation of human pluripotent stem cell-derived hepatocytes.</a> Development. 140, 3285-3296 (2013).</li><li>Kim, D. 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The authors have nothing to disclose.

Here, we present a stepwise method that induces HLCs from hESCs&#160;in three stages. In the first stage, Activin A and CHIR99021 were used to differentiate hESCs into DE. In the second stage, KO-DMEM and DMSO were used to differentiate DE into hepatic progenitor cells. In the third stage, HZM plus HGF, OSM and hydrocortisone 21-hemisuccinate sodium salt were used to continue to differentiate hepatic progenitor cells into HLCs.
The following critical steps need to be taken into consideration w...

The liver is a highly metabolic organ that plays several roles, including deoxidation, storing glycogen, and secretion and synthesis of proteins1. Various pathogens, drugs and heredity can cause pathological changes in the liver and affect its functions2,3. Hepatocytes, as the main functional unit of the liver, play an important role in artificial liver support systems and drug toxicity elimination. However, the resource of primary human hepatocytes is limited in cell-based therapy, as well as in liver disease research. Therefore, developing new sources of functional human hepatocytes is an important research direction in the field of regenerative medicine. Since 1998 when hESCs have been established4, hESCs have been widely considered by researchers because of their superior differentiation potential (they can differentiate into various tissues in a suitable environment) and high degree of self-renewability, and thus provide ideal source cells for bioartificial livers, hepatocyte transplantation and even liver tissue engineering5.
Currently, the hepatic differentiation efficiency can be greatly increased by enriching the endoderm6. In the lineage differentiation of stem cells into endoderm, levels of the transforming growth factor&#160;&#946;&#160;(TGF-&#946;)&#160;signaling and WNT signaling pathways are the key factors in the node of the endoderm formation stage. Activation of a high-level of TGF-&#946;&#160;and WNT signaling can promote the development of endoderm7,8. Activin A is a cytokine belonging to the TGF-&#946;&#160;superfamily. Therefore, Activin A is widely used in endoderm induction of human induced pluripotent stem cells (hiPSCs) and hESCs9,10. GSK3 is a serine-threonine protein kinase. Researchers have found that CHIR99021, a specific inhibitor of GSK3&#946;, can stimulate typical WNT signals, and can promote stem cell differentiation under certain conditions, suggesting that CHIR99021 has potential for inducing stem cell differentiation into endoderm 11,12,13.
Here we report an efficient and reproducible method for effectively inducing the differentiation of hESCs into functional HLCs. The sequential addition of Activin A and CHIR99021 produced about 89.7&#177;0.8% SOX17 (DE marker)-positive cells. After being further maturated in vitro, these cells expressed hepatic specific markers and exerted hepatocyte-like morphology (based on hematoxylin-eosin staining (H &#38; E)) and functions, such as uptake of indocyanine green (ICG), glycogen storage and CYP3 activity. The results show that hESCs can be successfully differentiated into mature functional HLCs by this method and can provide a basis for liver disease-related research and in vitro drug screening.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>2-Mercaptoethanol</td>
			<td>Sigma</td>
			<td>M7522</td>
			<td>For hepatic progenitor differentiation</td>
		</tr>
		<tr>
			<td>488 labeled goat against mouse IgG</td>
			<td>ZSGB-BIO</td>
			<td>ZF-0512</td>
			<td>For IF,second antibody</td>
		</tr>
		<tr>
			<td>488 labeled goat against Rabbit IgG</td>
			<td>ZSGB-BIO</td>
			<td>ZF-0516</td>
			<td>For IF,second antibody</td>
		</tr>
		<tr>
			<td>Accutase</td>
			<td>Stem Cell Technologies</td>
			<td>7920</td>
			<td>For cell passage</td>
		</tr>
		<tr>
			<td>Activin A</td>
			<td>peproTech</td>
			<td>120-14E</td>
			<td>For definitive endoderm formation</td>
		</tr>
		<tr>
			<td>Anti - Albumin (ALB)</td>
			<td>Sigma-Aldrich</td>
			<td>A6684</td>
			<td>For IF and WB, primary antibody</td>
		</tr>
		<tr>
			<td>Anti - Human Oct4</td>
			<td>Abcam</td>
			<td>Ab19587</td>
			<td>For IF, primary antibody</td>
		</tr>
		<tr>
			<td>Anti - &#945;-Fetoprotein (AFP)</td>
			<td>Sigma-Aldrich</td>
			<td>A8452</td>
			<td>For IF and WB, primary antibody</td>
		</tr>
		<tr>
			<td>Anti -SOX17</td>
			<td>Abcam</td>
			<td>ab224637</td>
			<td>For IF, primary antibody</td>
		</tr>
		<tr>
			<td>Anti-Hepatocyte Nuclear Factor 4 alpha (HNF4&#945;)</td>
			<td>Sigma-Aldrich</td>
			<td>SAB1412164</td>
			<td>For IF, primary antibody</td>
		</tr>
		<tr>
			<td>B-27 Supplement</td>
			<td>Gibco</td>
			<td>17504-044</td>
			<td>For definitive endoderm formation</td>
		</tr>
		<tr>
			<td>BSA</td>
			<td>Beyotime</td>
			<td>ST023-200g</td>
			<td>For cell blocking</td>
		</tr>
		<tr>
			<td>CHIR99021</td>
			<td>Sigma-Aldrich</td>
			<td>SML1046</td>
			<td>For definitive endoderm formation</td>
		</tr>
		<tr>
			<td>DAPI</td>
			<td>Beyotime</td>
			<td>C1006</td>
			<td>For nuclear staining</td>
		</tr>
		<tr>
			<td>DEPC-water</td>
			<td>Beyotime</td>
			<td>R0021</td>
			<td>For RNA dissolution</td>
		</tr>
		<tr>
			<td>DM3189</td>
			<td>MCE</td>
			<td>HY-12071</td>
			<td>For definitive endoderm formation</td>
		</tr>
		<tr>
			<td>DMEM/F12</td>
			<td>Gibco</td>
			<td>11320-033</td>
			<td>For cell culture</td>
		</tr>
		<tr>
			<td>DMSO</td>
			<td>Sigma-Aldrich</td>
			<td>D5879</td>
			<td>For hepatic progenitor differentiation</td>
		</tr>
		<tr>
			<td>DPBS</td>
			<td>Gibco</td>
			<td>14190-144</td>
			<td>For cell culture</td>
		</tr>
		<tr>
			<td>GlutaMAX</td>
			<td>Gibco</td>
			<td>35050-061</td>
			<td>For hepatic progenitor differentiation</td>
		</tr>
		<tr>
			<td>H&#38;E staining kit</td>
			<td>Beyotime</td>
			<td>C0105S</td>
			<td>For H&#38;E staining</td>
		</tr>
		<tr>
			<td>Hepatocyte growth factor (HGF)</td>
			<td>peproTech</td>
			<td>100-39</td>
			<td>For hepatocyte differentiation</td>
		</tr>
		<tr>
			<td>HepatoZYME-SFM (HZM)</td>
			<td>Gibco</td>
			<td>17705-021</td>
			<td>For hepatocyte differentiation</td>
		</tr>
		<tr>
			<td>Hydrocortisone-21-hemisuccinate</td>
			<td>Sigma-Aldrich</td>
			<td>H4881</td>
			<td>For hepatocyte differentiation</td>
		</tr>
		<tr>
			<td>Indocyanine</td>
			<td>Sangon Biotech</td>
			<td>A606326</td>
			<td>For Indocyanine staining</td>
		</tr>
		<tr>
			<td>Knock Out DMEM</td>
			<td>Gibco</td>
			<td>10829-018</td>
			<td>For hepatic progenitor differentiation</td>
		</tr>
		<tr>
			<td>Knock Out SR Multi-Species</td>
			<td>Gibco</td>
			<td>A31815-02</td>
			<td>For hepatic progenitor differentiation</td>
		</tr>
		<tr>
			<td>Matrigel hESC-qualified</td>
			<td>Corning</td>
			<td>354277</td>
			<td>For cell culture</td>
		</tr>
		<tr>
			<td>MEM NeAA</td>
			<td>Gibco</td>
			<td>11140-050</td>
			<td>For hepatic progenitor differentiation</td>
		</tr>
		<tr>
			<td>mTesR 5X Supplement</td>
			<td>Stem Cell Technologies</td>
			<td>85852</td>
			<td>For cell culture</td>
		</tr>
		<tr>
			<td>mTesR Basal Medium</td>
			<td>Stem Cell Technologies</td>
			<td>85851</td>
			<td>For cell culture</td>
		</tr>
		<tr>
			<td>Oncostatin (OSM)</td>
			<td>peproTech</td>
			<td>300-10</td>
			<td>For hepatocyte differentiation</td>
		</tr>
		<tr>
			<td>P450 - CYP3A4 (Luciferin - PFBE)</td>
			<td>Promega</td>
			<td>V8901</td>
			<td>For CYP450 activity</td>
		</tr>
		<tr>
			<td>PAS staining kit</td>
			<td>Solarbio</td>
			<td>G1281</td>
			<td>For PAS staining</td>
		</tr>
		<tr>
			<td>Pen/Strep</td>
			<td>Gibco</td>
			<td>15140-122</td>
			<td>For cell differentiation</td>
		</tr>
		<tr>
			<td>Peroxidase-Conjugated Goat anti-Mouse IgG</td>
			<td>ZSGB-BIO</td>
			<td>ZB-2305</td>
			<td>For WB,second antibody</td>
		</tr>
		<tr>
			<td>Primary Antibody Dilution Buffer for&#160;Western Blot</td>
			<td>Beyotime</td>
			<td>P0256</td>
			<td>For primary antibody dilution</td>
		</tr>
		<tr>
			<td>ReverTraAce qPCR RT Kit</td>
			<td>TOYOBO</td>
			<td>FSQ-101</td>
			<td>For cDNA Synthesis</td>
		</tr>
		<tr>
			<td>RNAiso Plus</td>
			<td>TaKaRa</td>
			<td>9109</td>
			<td>For RNA Isolation</td>
		</tr>
		<tr>
			<td>RPMI 1640</td>
			<td>Gibco</td>
			<td>11875093</td>
			<td>For definitive endoderm formation</td>
		</tr>
		<tr>
			<td>Skim milk</td>
			<td>Sangon Biotech</td>
			<td>A600669</td>
			<td>For second antibody preparation</td>
		</tr>
		<tr>
			<td>SYBR Green Master Mix</td>
			<td>Thermo Fisher Scientific</td>
			<td>A25742</td>
			<td>For RT-PCR Analysis</td>
		</tr>
		<tr>
			<td>Torin2</td>
			<td>MCE</td>
			<td>HY-13002</td>
			<td>For definitive endoderm formation</td>
		</tr>
		<tr>
			<td>Tween</td>
			<td>Sigma-Aldrich</td>
			<td>WXBB7485V</td>
			<td>For washing buffer preparation</td>
		</tr>
	</tbody>
</table>

an efficient method for directed hepatocyte-like cell induction from human embryonic stem cells

The potential functions of hepatocyte-like cells (HLCs) derived from human embryonic stem cells (hESCs) hold great promise for disease modeling and drug screening applications. Provided here is an efficient and reproducible method for differentiation of hESCs into functional HLCs. The establishment of an endoderm lineage is a key step in the differentiation to HLCs. By our method, we regulate the key signaling pathways by continuously supplementing Activin A and CHIR99021 during hESC differentiation into definitive endoderm (DE), followed by generation of hepatic progenitor cells, and finally HLCs with typical hepatocyte morphology in a stagewise method with completely defined reagents. The hESC-derived HLCs produced by this method express stage-specific markers (including albumin, HNF4&#945; nuclear receptor, and sodium taurocholate cotransporting polypeptide (NTCP)), and show special characteristics related to mature and functional hepatocytes (including indocyanine green staining, glycogen storage, hematoxylin-eosin staining and CYP3 activity), and can provide a platform for the development of HLC-based applications in the study of liver diseases.

The schematic diagram of HLC induction from hESCs and representative bright-field images of each differentiation stage are shown in Figure 1. In Stage I, Activin A and CHIR99021 were added for 3 days to induce stem cells to form endoderm cells. In Stage II, the endoderm cells differentiated into hepatic progenitor cells after being treated with differentiation medium for 5 days. In Stage III, early hepatocytes had matured and differentiated into HLCs after 10 days in HGF and OSM (<strong cla...

Watch this Scientific Journal Video about An Efficient Method for Directed Hepatocyte-Like Cell Induction from Human Embryonic Stem Cells at JoVE.com

An Efficient Method for Directed Hepatocyte-Like Cell Induction from Human Embryonic Stem Cells

This manuscript describes a detailed protocol for differentiation of human embryonic stem cells (hESCs) into functional hepatocyte-like cells (HLCs) by continuously supplementing Activin A and CHIR99021 during hESC differentiation into definitive endoderm (DE).

The potential functions of hepatocyte-like cells (HLCs) derived from human embryonic stem cells (hESCs) hold great promise for disease modeling and drug ...

Human embryonic stem cell-derived hepatocyte-like cells are useful in disease modeling and drug screening. This is an efficient and reproducible method for effectively inducing the differentiation of human embryonic stem cells into functional hepatocyte-like cells. An undifferentiated status and appropriate confluence of human embryonic stem cells are critical for a successful differentiation to hepatocyte-like cells.For stem cell maintenance, coat sterile six-well tissue culture-treated plates with one milliliter of 1X human embryonic stem cell-qualified Matrigel per well, and store them at four degrees Celsius overnight. Leave the plates at room temperature for 30 minutes before use. Thaw the cryo-preserved HESEs in a 37 degrees Celsius water bath for three minutes without shaking, then immediately transfer the stem cells by pipetting them into a 15-milliliter centrifuge tube containing four milliliters of pre-warmed, 37 degrees Celsius mTESR medium.Centrifuge the HESEs and aspirate the supernatant, then gently re-suspend the cells in one milliliter of mTESR medium. Aspirate the DMEM F-12 medium from the plate. Seed the cells into a six-well plate at a density of 1 x 10 to the 5th cells in two milliliters of mTESR, and incubate in a 5%carbon dioxide incubator.Maintain the cells by replacing the medium with preheated mTESR medium daily. Passage the cells at roughly 70 to 80%confluence, or when the cell colonies begin to make contact. For cells passaging, aspirate the medium and incubate the cells with one milliliter per well of enzyme solution for five minutes at 37 degrees Celsius.Transfer the cells by pipetting them into a 15-milliliter centrifuge tube containing four milliliters of DMEM F-12 pre-warmed to 37 degrees Celsius. Prepare 24-well plates by coating them with 250 microliters of 1X hESC-qualified Matrigel medium. Seed hESCs at a density of 1 to 1.5 times 10 to the 5th cells per well in 500 microliters of mTESR medium.Add both activin A to a final concentration of 100 nanograms per milliliter and CHIR99021 to a final concentration of three micromolar in an appropriate volume of preheated stage one differentiation basic medium. After three days of differentiation, differentiated cells should express markers of definitive endoderm cells, such as FOXA2, SOX17, GATA4, CXCR4, and FOXA1. On day three of differentiation, aspirate the medium, replace it with stage two medium, and incubate for 24 hours.Change the medium every other day on days four through eight. After eight days of differentiation, differentiated cells should express appropriate markers of hepatic progenitor cells, such as HNF4 alpha, AFP, TBX3, TTR, ALB, NTCP, CEBPA. On day eight, aspirate the stage two medium from the cells, and replace it with stage three medium.Allow cells to incubate for 10 days at 37 degrees Celsius in a carbon dioxide incubator, and change the media every other day with freshly-added differentiation factors. After 18 days of differentiation, differentiated cells should express characteristic markers of hepatocytes, such as AAT, ALB, TTR, HNF4 alpha, NTCP, ASGR1, CYP3A4. The schematic diagram of hepatocyte-like cells from hESCs and bright field images of each differentiation stage are shown.In stage one, activin A and CHIR99021 were added for three days to induce stem cells to form endoderm cells. In stage two, the endoderm cells differentiated into hepatic progenitor cells after being treated with a differentiation medium for five days. In stage three, after 10 days, early hepatocytes had matured and differentiated into hepatocyte-like cells in hepatocyte growth factor and oncostatin.In the final stage of differentiation, cells showed a typical hepatocyte phenotype. RT-PCR, immunofluorescence staining, and western blotting were used to detect markers of endoderm cells, hepatic precursor cells, and mature hepatocytes. The differentiated cells showed high expression levels of differentiation-related genes and proteins in each stage, such as endoderm markers SOX17 at day three, hepatic precursor marker HNF4 alpha at day eight, AFP at day 14, and mature hepatocyte marker ALB at day 18.The HLCs exhibited green staining and extensive cytoplasmic acid shift staining. The hepatocytes showed typical bi-nucleated morphology. The enzymatic activity of CYP3A4, the essential metabolic CYP in the liver in HLCs, was confirmed with an enzyme assay.Siting of human embryonic stem cells at an appropriate density and starting differentiation on the following date are critical. In stage one, touch the media gently because the cells are prone to float up. The combination of activin A and other small molecules may further improve the differentiation efficiencies, and produce more mature hepatocyte-like cells in this procedure.This technique can provide a platform to explore hepatocyte transplantation, liver tissue engineering, bioartificial livers, and disease modeling.

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JoVE Journal

Immunology and Infection

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