This work was supported by the Ministry of Education, Culture, Sports, Science and Technology grant number [23390072].

This study used commercially obtained human iPS cells (253G1 strain) (see Table of Materials).
1. Maintenance of human iPS cells
<ol>
	<li>Maintain human iPS cells in feeder-free conditions in AK02 medium on culture dishes coated with 0.25 &#181;g/cm2 iMatrix-511 (see Table of Materials).</li>
</ol>
2. Hepatic differentiation of human iPS cells in 2D cultures
NOTE: Refer to Figure 1A for the daily schedule of hepatic differentiation. Throughout the process, use 6-well culture plates and add 2 mL of the designated wash or culture medium to each well. Maintain the cell culture condition at 100% humidity, 5% CO2, and 20% O2 at 37 &#176;C.
<ol>
	<li>Coat each well of a 6-well plate with 1 mL of basement membrane matrix (diluted 1/25 in PBS (-)), and incubate at 37 &#176;C for 1 h.</li>
	<li>Passage human iPS cells onto the coated dish at a density of 20,000-30,000 cells/cm&#178; using AK02N medium supplemented with 10 &#181;M ROCK inhibitor (Y-27632) (see Table of Materials). Replace the medium without Y-27632 the following day and culture for an additional 2 days.</li>
	<li>Wash the cells once with RPMI-1640 medium. Initiate endoderm differentiation by replacing the medium with RPMI-B27-Glu (RPMI-1640 + 2% B27 Insulin + 1% Dipeptide L-Alanyl-L-Glutamine) supplemented with 3-6 &#181;M CHIR-99021 and 100 ng/mL Activin A for 24 h (see Table of Materials).</li>
	<li>Replace the medium with RPMI-B27-Glu supplemented with 50 ng/mL Activin A for 24 h.</li>
	<li>To induce hepatic progenitor differentiation, replace the medium with RPMI-B27-Glu supplemented with 1% dimethyl sulfoxide (DMSO) for 5 days.</li>
	<li>To promote hepatocyte maturation, switch to hepatocyte maturation medium: Leibovitz&#39;s L-15 medium containing 10 &#181;M hydrocortisone 21-hemisuccinate, 8.3% tryptose phosphate broth, 100 nM dexamethasone (DEX), 50 &#181;g/mL sodium-L-ascorbate, 0.58% insulin-transferrin-selenium (ITS), 8.3% fetal bovine serum (FBS), 2 mM Dipeptide L-Alanyl-L-Glutamine, and 100 nM N-Hexanoic-Try-Ile-(6)-amino Hexanoic amide (Dihexa) (see Table of Materials).</li>
	<li>Change the medium every 2 days for 20 days. Sort the cells approximately 27 days after initiating differentiation.</li>
</ol>
3. Cell preparation for purification of human iPS cells-derived hepatocytes
<ol>
	<li>Wash hepatic differentiated cells with 2 mL PBS (-) per well.</li>
	<li>Add 1 mL enzyme solution per well, which includes 0.1% collagenase, 0.083% trypsin, 10 &#181;M ROCK inhibitor (Y-27632), 20 nM ciclosporin A, and 50 &#181;g/mL sodium-L-ascorbate in Ads buffer (116 mM NaCl, 12.5 mM NaH2PO4, 20 mM HEPES, 5.4 mM KCl, 5.6 mM glucose, and 0.8 mM MgSO4; pH 7.35) (see Table of Materials). Detach cells from the plates by horizontally rotating at 37 &#176;C for about 2 h.</li>
	<li>After confirming that cells are detached and rounded under a microscope, disperse them into single cells by gentle pipetting, and collect them in a 50 mL tube.</li>
	<li>Centrifuge cells at 200 x g for 5 min at 18 &#176;C to pellet them. Remove the supernatant using an aspirator.</li>
	<li>Stain the mitochondria of the cells by dispersing them in 5 mL of hepatocyte maturation medium containing 100 nM TMRM (tetramethylrhodamine, methl ester) (see Table of Materials). Incubate for 30 min at 37 &#176;C while protecting from light by wrapping in aluminum foil.</li>
	<li>Centrifuge the cells at 200 x g for 5 min at 18 &#176;C to pellet them. Remove the supernatant.</li>
	<li>Resuspend the cells with 1-5 mL of cold Ads buffer containing 2% FBS.</li>
	<li>Count the cell number using a 0.4% Trypan blue solution and a cell count plate.</li>
	<li>Centrifuge the cells at 200 x g for 5 min at 4 &#176;C to pellet them. Remove the supernatant.</li>
	<li>Dilute an anti-ALCAM antibody (primary antibody, see Table of Materials) at a 1:50 ratio in Ads buffer, and add 100 &#181;L of the diluted antibody per 106 cells. Stain the cells for 50 min on ice. Prepare cells that are not stained with the primary antibody as a negative control.</li>
	<li>Wash the cells with cold Ads buffer containing 2% FBS twice.</li>
	<li>Dilute an Alexa Fluor 488 donkey anti-goat IgG (secondary antibody, see Table of Materials) at a 1:100 ratio in Ads buffer, and add 100 &#181;L of the diluted antibody per 106 cells. Stain the cells for 30 min on ice. Stain cells that were not stained with the primary antibody using the secondary antibody.</li>
	<li>Wash the cells with cold Ads buffer containing 2% FBS twice.</li>
	<li>Resuspend the cells in Ads buffer and filter them through a snap cap cell strainer (35 &#181;m mesh) just before sorting by FACS to remove large cell clumps and debris.</li>
</ol>
4. FACS analyses and sorting of human iPS cells-derived hepatocytes
<ol>
	<li>Set up the FACS machine for cell sorting following the manufacturer&#39;s instructions (see Table of Materials). 
	NOTE: Use an 85 &#181;m or 100 &#181;m nozzle size and an ND filter of 2.0 for hepatocytes. Use the FITC channel for detecting Alexa Flour 488 for ALCAM and the PE channel for detecting TMRM fluorescence for mitochondria.</li>
	<li>Adjust the FSC (forward scatter) and SSC (side scatter) voltages to properly visualize the cell population.</li>
	<li>Adjust the voltages of the FITC and PE fluorescent channels. Start with unlabeled cells and center the cell population at the bottom of each channel plot. Ensure labeled cells are appropriately positioned within the plot.</li>
	<li>Use a common gating strategy to eliminate doublets: Gate the major FSC-A vs. SSC-A population (Figure 2A), followed by FSC-H vs. -W, and then SSC-H vs. -W (Figure 2B,C).</li>
	<li>Gate the TMRMhi and ALCAM+ population (P2 in Figure 2E) to sort hepatocytes. Gate the TMRMhi and ALCAM- population (P1 in Figure 2E) to sort non-hepatocytes. Collect sorted hepatocytes and non-hepatocytes in 15 mL collection tubes containing hepatocyte maturation medium.</li>
	<li>Centrifuge the collection tube containing the sorted cells at 200 x g for 5 min at 18 &#176;C.</li>
	<li>Remove the supernatant and resuspend the cells in hepatocyte maturation medium.</li>
	<li>Seed the cells on mitomycin C-treated mouse embryonic fibroblasts (MEFs) or gel-like basement membrane matrix with hepatocyte maturation medium supplemented with 10 &#181;M Y-27632 and 20 nM ciclosporin A. Culture the cells in a 37 &#176;C CO2 incubator for 5 days.</li>
</ol>
5. Immunocytochemistry for detection of human iPS cells-derived hepatocytes
<ol>
	<li>Wash the cells cultured for 5 days after sorting with PBS (-).</li>
	<li>Fix the cells with 4% paraformaldehyde for 5 min at room temperature.</li>
	<li>Wash the cells with TBS-T buffer (1x TBS with 1% Tween 20) twice to remove the paraformaldehyde.</li>
	<li>Incubate the cells with 0.1% Triton X-100 diluted TBS-T buffer for 5 min at room temperature.</li>
	<li>Wash the cells with TBS-T buffer twice to remove Triton X-100.</li>
	<li>Add commercially available blocking solution (see Table of Materials) to the cells for 30 min at room temperature.</li>
	<li>Add primary antibodies against albumin (hepatocyte marker) and human nuclear antigen (hNA, see Table of Materials), diluted 1:50 in blocking solution.</li>
	<li>Incubate the cells at 4 &#176;C overnight. Wash the cells with TBS-T buffer twice.</li>
	<li>Add secondary antibodies: Alexa Fluor 488 donkey anti-rabbit IgG and Alexa Fluor 546 donkey anti-mouse IgG, diluted 1:100 in blocking solution (see Table of Materials).</li>
	<li>Incubate the cells at room temperature for 30 min. Wash the cells with TBS-T buffer twice.</li>
	<li>Evaluate hepatocyte purity by counting albumin-positive and hNA-positive cells under a fluorescence microscope. Calculate the percentage of albumin-positive cells per hNA-positive cell for both the P1 and P2 populations.</li>
</ol>

Purification of Human iPSC-Derived Hepatocytes by Mitochondrial-ALCAM Sorting

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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=Balancing+serendipity+and+reproducibility:+Pluripotent+stem+cells+as+experimental+systems+for+intellectual+and+developmental+disorders.">Balancing serendipity and reproducibility: Pluripotent stem cells as experimental systems for intellectual and developmental disorders.</a> Stem Cell Reports. 16 (6), 1446-1457 (2021).</li><li>Chen, C. X. -. 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=Standardized+quality+control+workflow+to+evaluate+the+reproducibility+and+differentiation+potential+of+human+iPSCs+into+neurons.">Standardized quality control workflow to evaluate the reproducibility and differentiation potential of human iPSCs into neurons.</a> bioRxiv. , (2021).</li><li>Duinsbergen, D., Salvatori, D., Eriksson, M., Mikkers, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumors+originating+from+induced+pluripotent+stem+cells+and+methods+for+their+prevention.">Tumors originating from induced pluripotent stem cells and methods for their prevention.</a> Annals of the New York Academy of Sciences. 1176, 197-204 (2009).</li><li>Nori, 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=Long-term+safety+issues+of+iPSC-based+cell+therapy+in+a+spinal+cord+injury+model:+oncogenic+transformation+with+epithelial-mesenchymal+transition.">Long-term safety issues of iPSC-based cell therapy in a spinal cord injury model: oncogenic transformation with epithelial-mesenchymal transition.</a> Stem Cell Reports. 4 (3), 360-373 (2015).</li><li>Hentze, 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=Teratoma+formation+by+human+embryonic+stem+cells:+evaluation+of+essential+parameters+for+future+safety+studies.">Teratoma formation by human embryonic stem cells: evaluation of essential parameters for future safety studies.</a> Stem Cell Research. 2 (3), 198-210 (2009).</li><li>Anderson, 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=Transgenic+enrichment+of+cardiomyocytes+from+human+embryonic+stem+cells.">Transgenic enrichment of cardiomyocytes from human embryonic stem cells.</a> Molecular Therapy. 15 (11), 2027-2036 (2007).</li><li>Hidaka, 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=Chamber-specific+differentiation+of+Nkx2.5-positive+cardiac+precursor+cells+from+murine+embryonic+stem+cells.">Chamber-specific differentiation of Nkx2.5-positive cardiac precursor cells from murine embryonic stem cells.</a> The FASEB Journal. 17 (6), 740-742 (2003).</li><li>Gassanov, N., Er, F., Zagidullin, N., Hoppe, U. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelin+induces+differentiation+of+ANP-EGFP+expressing+embryonic+stem+cells+towards+a+pacemaker+phenotype.">Endothelin induces differentiation of ANP-EGFP expressing embryonic stem cells towards a pacemaker phenotype.</a> The FASEB Journal. 18 (14), 1710-1712 (2004).</li><li>Duan, 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=Differentiation+and+enrichment+of+hepatocyte-like+cells+from+human+embryonic+stem+cells+in+vitro+and+in+vivo.">Differentiation and enrichment of hepatocyte-like cells from human embryonic stem cells in vitro and in vivo.</a> Stem Cells. 25 (12), 3058-3068 (2007).</li><li>Takayama, 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=Enrichment+of+high-functioning+human+iPS+cell-derived+hepatocyte-like+cells+for+pharmaceutical+research.">Enrichment of high-functioning human iPS cell-derived hepatocyte-like cells for pharmaceutical research.</a> Biomaterials. 161, 24-32 (2018).</li><li>Hattori, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nongenetic+method+for+purifying+stem+cell-derived+cardiomyocytes.">Nongenetic method for purifying stem cell-derived cardiomyocytes.</a> Nature methods. 7, 61-66 (2009).</li><li>Yamashita, H., Fukuda, K., Hattori, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hepatocyte-like+cells+derived+from+human+pluripotent+stem+cells+can+be+enriched+by+a+combination+of+mitochondrial+content+and+activated+leukocyte+cell+adhesion+molecule.">Hepatocyte-like cells derived from human pluripotent stem cells can be enriched by a combination of mitochondrial content and activated leukocyte cell adhesion molecule.</a> JMA Journal. 2 (2), 174-183 (2019).</li><li>Fernandez-Vizarra, E., Enr&#237;quez, J., P&#233;rez-Martos, A., Montoya, J., Fern&#225;ndez-Silva, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue-specific+differences+in+mitochondrial+activity+and+biogenesis.">Tissue-specific differences in mitochondrial activity and biogenesis.</a> Mitochondrion. 11, 207-213 (2010).</li><li>Swart, G. 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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Small-molecule-driven+hepatocyte+differentiation+of+human+pluripotent+stem+cells.">Small-molecule-driven hepatocyte differentiation of human pluripotent stem cells.</a> Stem Cell Reports. 4 (5), 939-952 (2015).</li><li>Hirata, 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=ALCAM+(CD166)+is+a+surface+marker+for+early+murine+cardiomyocytes.">ALCAM (CD166) is a surface marker for early murine cardiomyocytes.</a> Cells, Tissues, Organs. 184 (3-4), 172-180 (2006).</li><li>Tohyama, 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=Distinct+metabolic+flow+enables+large-scale+purification+of+mouse+and+human+pluripotent+stem+cell-derived+cardiomyocytes.">Distinct metabolic flow enables large-scale purification of mouse and human pluripotent stem cell-derived cardiomyocytes.</a> Cell Stem Cell. 12 (1), 127-137 (2013).</li></ol>

The authors have nothing to disclose.

Due to their functions in nutrient metabolism and detoxification, hepatocytes possess a relatively large number of mitochondria compared to other cell types15. ALCAM is a member of the immunoglobulin superfamily and plays a role in cell adhesion and migration. It is expressed in various cell types, including hepatic, epithelial, lymphocytic, myeloid, fibroblast, and neuronal cells16. By utilizing a combination of the mitochondria-based method and the ALCAM antibody, human i...

Embryonic and induced pluripotent stem cells (ES and iPS, respectively) are considered promising cell sources for regenerative therapies. However, the efficiency of differentiating these cells into specific target cell types can vary, even when using the same cell line, protocol, and experimenter1,2,3,4. This variability may be attributed to the high sensitivity of human ES/iPS cells to their environment. Therefore, it is currently difficult to consistently obtain pure target cells. To achieve highly safe regenerative medicine, it is crucial to eliminate proliferative cells and undifferentiated stem cells in therapeutic cells, and advanced purification technology for target cells is essential5,6,7.
A cell sorter is a device that instantaneously analyzes individual cells and sorts live cells of interest based on the fluorescent signal strengths, offering a promising solution. This can be accomplished through antibody staining of cell type-specific surface markers or by utilizing cell type-specific reporter gene expressions. Using this technique, there are several reports on methods for purifying pluripotent stem cell-derived cardiomyocytes8,9,10 and hepatocytes11,12. Hattori et al. developed an innovative mitochondrial purification method using a cell sorter13. Taking advantage of the fact that cardiomyocytes have high energy demands through mitochondrial activity, staining the cells with the live mitochondria-indicative dye TMRM (tetramethylrhodamine methyl ester) can be used to label and highly purify cardiomyocytes by FACS from human ES cell-derived embryoid bodies containing various cell types. The absence of tumorigenicity was confirmed by teratoma formation assays with the purified cardiomyocytes. Furthermore, Yamashita et al. unexpectedly discovered a method to purify hepatocytes from human ES cell-derived embryoid bodies by isolating fractions with high mitochondrial activity and ALCAM-positive expression14. The rationale for this method is that hepatocytes also have a relatively high number of mitochondria due to their high consumption of ATP for nutrient metabolism and detoxification15, and hepatocytes express ALCAM, a member of the immunoglobulin superfamily, which plays a role in cell adhesion and migration16.
Previous highly purifying methods for pluripotent stem cell-derived hepatocytes required genetic modifications, and non-genetic purification methods had low efficiency17. The mitochondrial non-genetic method holds merit for achieving high purity. When hepatic progenitor cells are needed, CD133 and CD13- or Dlk1-based methods18,19 can be chosen. Although the accuracy of genome editing technology has advanced, the potential risk of unforeseen genomic changes (e.g., carcinogenesis) cannot be entirely eliminated. Methods based on mitochondrial activity, without involving genetic modification, can be free from such risks.
As a result of examining various mitochondrial indicators in neonatal rat cardiomyocytes, TMRM was observed to disappear completely within 24 h, whereas other dyes remained for at least 5 days13. Moreover, it is important to note that TMRM and JC-1 did not impact cell viability when assessed with the 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, while other dyes demonstrated varying effects on cell viability13. TMRM demonstrates higher safety.
To date, several two-dimensional (2D) differentiation methods have been developed as more efficient approaches for inducing differentiation compared to three-dimensional (3D) embryoid body formation. This is because step-wise differentiation-inducing compounds or cytokines can be uniformly administered to cells on a 2D plane, rather than in a 3D space. In this study, the previously reported method20 was modified to induce differentiation into human iPS cell-derived hepatocytes. Here, the details of the procedures for the up-to-date 2D differentiation and purification of hepatocytes derived from human iPS cells are described.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>253G1 human iPS cell line</td>
			<td>RIKEN BioResource Research Center</td>
			<td>HPS0002</td>
			<td></td>
		</tr>
		<tr>
			<td>4% paraformaldehyde</td>
			<td>FUJIFILM Wako Pure Chemical Corporation</td>
			<td>163-20145</td>
			<td></td>
		</tr>
		<tr>
			<td>Activin A Solution, Human, Recombinant</td>
			<td>NACALAI TESQUE, INC.</td>
			<td>18585</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Nuclei Antibody, clone 235-1</td>
			<td>Chemicon</td>
			<td>MAB1281</td>
			<td>Antibody against human nuclear antigen</td>
		</tr>
		<tr>
			<td>B-27 Supplement (50x), serum free</td>
			<td>Thermo Fisher Scientific</td>
			<td>17504044</td>
			<td></td>
		</tr>
		<tr>
			<td>BD FACSAria III</td>
			<td>BD Biosciences</td>
			<td></td>
			<td>Cell sorter</td>
		</tr>
		<tr>
			<td>CHIR-99021</td>
			<td>MedChemExpress</td>
			<td>HY-10182&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>Ciclosporin A</td>
			<td>FUJIFILM Wako Pure Chemical Corporation</td>
			<td>035-18961</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagenase</td>
			<td>FUJIFILM Wako Pure Chemical Corporation</td>
			<td>034-22363</td>
			<td></td>
		</tr>
		<tr>
			<td>Corning Matrigel Growth Factor Reduced (GFR) Basement Membrane Matrix</td>
			<td>Corning</td>
			<td>354230</td>
			<td>Gel-like basement membrane matrix</td>
		</tr>
		<tr>
			<td>CultureSure Y-27632</td>
			<td>FUJIFILM Wako Pure Chemical Corporation</td>
			<td>036-24023</td>
			<td>ROCK inhibitor</td>
		</tr>
		<tr>
			<td>Dexamethasone</td>
			<td>FUJIFILM Wako Pure Chemical Corporation</td>
			<td>047-18863</td>
			<td></td>
		</tr>
		<tr>
			<td>Dimethyl sulfoxide (DMSO)</td>
			<td>FUJIFILM Wako Pure Chemical Corporation</td>
			<td>047-29353</td>
			<td></td>
		</tr>
		<tr>
			<td>Donkey anti-Goat IgG (H+L) Cross-Adsorbed Secondary Antibody, Alexa Fluor 488</td>
			<td>Thermo Fisher Scientific</td>
			<td>A-11055</td>
			<td></td>
		</tr>
		<tr>
			<td>Donkey anti-Mouse IgG (H+L) Highly Cross-Adsorbed Secondary Antibody, Alexa Fluor 546</td>
			<td>Thermo Fisher Scientific</td>
			<td>A10036</td>
			<td></td>
		</tr>
		<tr>
			<td>Donkey anti-Rabbit IgG (H+L) Highly Cross-Adsorbed Secondary Antibody, Alexa Fluor 488</td>
			<td>Thermo Fisher Scientific</td>
			<td>A-21206</td>
			<td></td>
		</tr>
		<tr>
			<td>Falcon 5 mL Round Bottom Polystyrene Test Tube, with Cell Strainer Snap Cap</td>
			<td>Corning</td>
			<td>352235</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Biowest</td>
			<td>51820-500</td>
			<td></td>
		</tr>
		<tr>
			<td>GlutaMAX Supplement</td>
			<td>Thermo Fisher Scientific</td>
			<td>35050061</td>
			<td>Dipeptide L-Alanyl-L-Glutamine</td>
		</tr>
		<tr>
			<td>Human/Mouse/Rat/Canine ALCAM/CD166 Antibody</td>
			<td>R&#38;D Systems</td>
			<td>AF1172</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrocortisone 21-hemisuccinate sodium salt</td>
			<td>Sigma-Aldrich</td>
			<td>H2270</td>
			<td></td>
		</tr>
		<tr>
			<td>iMatrix-511 silk</td>
			<td>Nippi</td>
			<td>892021</td>
			<td></td>
		</tr>
		<tr>
			<td>ImmunoBlock</td>
			<td>KAC</td>
			<td>CTKN001</td>
			<td>Blocking solution</td>
		</tr>
		<tr>
			<td>ITS-G Supplement(&#215;100)</td>
			<td>FUJIFILM Wako Pure Chemical Corporation</td>
			<td>090-06741</td>
			<td></td>
		</tr>
		<tr>
			<td>Leibovitz&#39;s L-15 Medium</td>
			<td>FUJIFILM Wako Pure Chemical Corporation</td>
			<td>128-06075</td>
			<td></td>
		</tr>
		<tr>
			<td>N-Hexanoic-Try-Ile-(6)-amino Hexanoic amide (Dihexa)</td>
			<td>Toronto Research Chemicals</td>
			<td>H293745</td>
			<td></td>
		</tr>
		<tr>
			<td>Polyclonal Rabbit Anti-Human Albumin</td>
			<td>Dako</td>
			<td>A0001</td>
			<td></td>
		</tr>
		<tr>
			<td>Polyoxyethylene Sorbitan Monolaurate (Tween 20)</td>
			<td>NACALAI TESQUE, INC.</td>
			<td>28353-85</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI-1640</td>
			<td>FUJIFILM Wako Pure Chemical Corporation</td>
			<td>189-02025</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium L-Ascorbate</td>
			<td>NACALAI TESQUE, INC.</td>
			<td>03422-32</td>
			<td></td>
		</tr>
		<tr>
			<td>StemFit AK02N</td>
			<td>REPROCELL</td>
			<td>RCAK02N</td>
			<td></td>
		</tr>
		<tr>
			<td>TBS (10x)</td>
			<td>NACALAI TESQUE, INC.</td>
			<td>12748-31</td>
			<td></td>
		</tr>
		<tr>
			<td>Tetramethylrhodamine, methyl ester (TMRM)</td>
			<td>Thermo Fisher Scientific</td>
			<td>T668</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>NACALAI TESQUE, INC.</td>
			<td>28229-25</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypan Blue Solution</td>
			<td>NACALAI TESQUE, INC.</td>
			<td>20577-34</td>
			<td></td>
		</tr>
		<tr>
			<td>TRYPSIN 250</td>
			<td>Difco</td>
			<td>215240</td>
			<td></td>
		</tr>
		<tr>
			<td>Tryptose phosphate broth solution</td>
			<td>Sigma-Aldrich</td>
			<td>T8159</td>
			<td></td>
		</tr>
	</tbody>
</table>

application of live mitochondria staining in cell-sorting to purify hepatocytes derived from human induced pluripotent stem cells

Human embryonic stem (ES) and induced pluripotent stem (iPS) cells have potential applications in cell-based regenerative medicine for treating severely diseased organs due to their unlimited proliferation and pluripotent properties. However, differentiating human ES/iPS cells into 100% pure target cell types is challenging due to their high sensitivity to the environment. Tumorigenesis after transplantation is caused by contaminated, proliferating, and undifferentiated cells, making high-purification technology essential for the safe realization of regenerative medicine. To mitigate the risk of tumorigenesis, a high-purification technology has been developed for human iPS cell-derived hepatocytes. The method employs FACS (fluorescence-activated cell sorting) using a combination of high mitochondrial content and the cell-surface marker ALCAM (activated leukocyte cell adhesion molecule) without genetic modification. 97% &plusmn; 0.38% (n = 5) of the purified hepatocytes using this method exhibited albumin protein expression. This article aims to provide detailed procedures for this method, as applied to the most current two-dimensional differentiation method for human iPS cells into hepatocytes.

Author Spotlight: Advancing Hepatocyte Purification from Human Induced Pluripotent Stem Cells for Regenerative Medicine

Application of Live Mitochondria Staining in Cell-Sorting to Purify Hepatocytes Derived from Human Induced Pluripotent Stem Cells

The scope of our research is to purify human induced pluripotent stem cell-derived hepatocytes, using without genetic modification. We aim to address the issue of the tumorigenic risk associated with the undifferentiated cells, among those differentiated from human iPS cells. One of the current experimental challenges is a low cell purity, due to the mechanical storage of sorting.We are developing a new purification method, that utilizes the unique metabolism features of hepatocytes, for large-scale purification. One non-cell sorting method for hepatic progenitor cells cannot obtain pure hepatocytes. Another one for mature hepatocytes can only treat a small fraction of hepatocytes, because of the limited expression of the marker protein.In contrast, our approach can obtain hepatocytes at different maturation levels with a higher eve. Human iPS cell-derived hepatocytes are extremely immature, and show more reduced hepatocyte macro expression after purification. Our future goal is to enhance hepatocyte modulation using organoidal technology and day-to-day advancements to regenerative medicine and drug discovery.

The timeline of the processes inducing human iPS cells to differentiate into hepatocytes through 2D culture (Figure 1A) and representative cell features (Figure 1B) are shown. Approximately on differentiation day 12, cells began to exhibit polygonal cell shapes and round nuclei, characteristic of hepatocytes. Some hepatocytes also displayed multinucleation.
FACS analysis was performed using the cells on differentiation day 27. To iden...

Watch this Scientific Journal Video about Application of Live Mitochondria Staining in Cell-Sorting to Purify Hepatocytes Derived from Human Induced Pluripotent Stem Cells at JoVE.com

Hepatocytes derived from pluripotent stem cells can be purified through cell sorting, using a combination of mitochondrial and activated leukocyte cell adhesion molecule (ALCAM, also known as CD166) staining.

Human embryonic stem (ES) and induced pluripotent stem (iPS) cells have potential applications in cell-based regenerative medicine for treating severely ...

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Research

JoVE Journal

Biology

346 Views.  Kansai Medical University. The scope of our research is to purify human induced pluripotent stem cell-derived hepatocytes, using without genetic modification. We aim to address the issue of the tumorigenic risk associated with the undifferentiated cells, among those differentiated from human iPS cells. One of the current experimental challenges is a low cell purity, due to the mechanical storage of sorting.We are developing a new purification method, that utilizes the unique metabolism features of hepatocytes, f...

Video: Author Spotlight: Advancing Hepatocyte Purification from Human Induced Pluripotent Stem Cells for Regenerative Medicine

Hepatic Differentiation of Human-Induced Pluripotent Stem Cells in 2D Cultures

To begin, coat each well of a six-well plate with one milliliter of basement membrane matrix and incubate at 37 degrees Celsius for one hour. Remove the coated matrix from the plate and add human-induced pluripotent stem cells prepared in AK02N medium supplemented with 10 micromolar ROCK inhibitor. Incubate the cells at 37 degrees Celsius and 5%carbon dioxide for three days.After three days, on day zero of the initiating hepatic differentiation, wash the cells once with RPMI 1640 medium. Next, to initiate endoderm differentiation, add RPMI B27 GlutaMAX supplemented with three to six micromolar CHIR 99021 and 100 nanograms per milliliter Activin A into the plate. Incubate the cells at 37 degrees Celsius and 5%carbon dioxide for 24 hours.On day one, replace the existing medium with RPMI B27 GlutaMAX supplemented with 50 nanograms per milliliter of Activin A.Incubate the cells at 37 degrees Celsius and 5%carbon dioxide for 24 hours. On day two, to induce hepatic progenitor differentiation, replace the existing medium with RPMI B27 GlutaMAX medium supplemented with 1%dimethyl sulfoxide, and continue incubation for up to five days. On day seven, to initiate hepatocyte maturation, switch to hepatocyte maturation medium and incubate for 20 days at 37 degrees Celsius and 5%carbon dioxide.On day 27, human-induced pluripotent stem cells displayed polygonal cell shapes and rounded nuclei, characteristics of hepatocytes.

Cell Preparation for Purification of Human-Induced Pluripotent Stem Cells-Derived Hepatocytes

After 27 days of initiating hepatic differentiation of human induced pluripotent stem cells, wash the cells with two milliliters of PBS per well. Prepare the enzyme solution in ADS buffer using the given components. Add one milliliter of solution per well of a six well plate.Place the plate at 37 degrees Celsius on a rotating shaker for about two hours to detach the cells from the plate. Confirm the cell detachment under a microscope, then pipette the cell suspension to disperse into single cells, and collect them in a 50 milliliter tube containing the hepatocyte maturation medium. Centrifuge the cell suspension at 200G for five minutes at 18 degrees Celsius.And using an aspirator, remove the supernatant. To stain the mitochondria of cells, resuspend the pellet in five milliliters of hepatocyte maturation medium containing 100 nanomolar TMRM. Incubate the cells for 30 minutes at 37 degrees Celsius while protecting them from light.Again, centrifuge the cell suspension and resuspend the pellet in one to five milliliters of cold ADS buffer containing 2%FBS. After cell counting, aliquot 500, 000 cells to a 1.5 milliliter tube and label it as the no primary antibody control. Centrifuge the remaining cell suspension at 200G for five minutes at four degrees Celsius, and remove the supernatant.Add 100 microliters of diluted primary antibody per one million cells. Transfer the cell suspension to a 1.5 milliliter tube and incubate on ice for 50 minutes. After incubation, centrifuge the cell suspension and wash the cells twice with cold ADS buffer containing 2%FBS.Now add 100 microliters of diluted secondary antibody per one million cells to the primary antibody, stained or unstained cells, and incubate for 30 minutes on ice. Again, centrifuge the cell suspension and wash the cells twice with cold ADS buffer containing 2%FBS. After resuspending the cells in ADS buffer, filter them through a snap cap cell strainer and place the tube on ice.

Fluorescence-Activated Cell Sorting of Hepatocytes Derived from Human Induced Pluripotent Stem Cells

To begin, set up the fluorescence-activated cell sorting, or FACS machine, for cell sorting following the manufacturer's instructions. Place the sample tube on the FACS machine and load it. Gate TMRM-high and ALCAM negative population in the P1 region to sort non-hepatocytes.Then gate the TMRM high and ALCAM positive population in the P2 region to sort hepatocytes. Collect sorted cells in 15-milliliter collection tubes containing hepatocyte maturation medium. After sorting, remove the collection tube from the FACS machine.Centrifuge the sorted cell suspension at 200 G for five minutes at 18 degrees Celsius. Remove the supernatant, and re-suspend the pellet in two milliliters of hepatocyte maturation medium with 10 micromolar rock inhibitor and 20 nanomolar cyclosporine A.Seed the cells on mitomycin C-treated mouse embryonic fibroblasts with hepatocyte maturation medium in a six-well plate. Culture the cells in a 37-degree Celsius carbon dioxide incubator for five days before immuno staining for hepatocyte purity test.FACS analysis conducted on day 27 of hepatic differentiation revealed TMRM high and ALCAM positive population. The immunohistochemical staining of P1 and P2 cells cultured on mouse embryonic fibroblasts after sorting is shown. A purity test by counting albumin-positive cells showed 0%of P1, and approximately 97%of P2 cells were hepatocyte-like cells.