Hepatocyte Differentiation from Human ES Cells using the Simple Embryoid Body Formation Method and the Staged-Additional Cocktail

To induce hepatocytes from human embryonic stem (hES) cells easily and effectively, a simple suspension culture method that separates ES colonies with a scraper and transfers them into newly developed, nonadherent MPC (2-methacryloyloxyethyl phosphorylcholine) plates, and the staged-additional cocktail method, including growth factors, cytokines, and Lanford serum-free medium, were developed and evaluated mainly by morphological analysis. The formed embryoid bodies (EBs) showed compact cellular agglomeration until day 4 and later formed coeloms in their interior. RT-PCR (reverse transcriptase-polymerase chain reaction) analysis showed that they are gene markers of the three germ layers. Mesenchymal cells with rough endoplasmic reticulum (rER) and extracellular matrix (ECM), and without junctions, were recognized in the interior of the EBs by transmission electron microscopy (TEM) in addition to epithelial cells. When they were stimulated by the staged-additional cocktail, they expressed albumin-positive immunoreactivity, indocyanine green (ICG) uptake, and typical ultrastructures of the hepatocytes, including bile canaliculi. These results indicate that these combined methods promote EB formation and hepatocyte differentiation from hES cells

Enrichment of Pluripotent Stem Cell-Derived Hepatocyte-Like Cells by Ammonia Treatment.

Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) are potential resources for the regeneration of defective organs, including the liver. However, some obstacles must be overcome before this becomes reality. Undifferentiated cells that remain following differentiation have teratoma-forming potential. Additionally, practical applications require a large quantity of differentiated cells, so the differentiation process must be economical. Here we describe a DNA microarray-based global analysis of the gene expression profiles of differentiating human pluripotent stem cells. We identified differences and commonalities among six human pluripotent stem cell lines: the hESCs KhES1, KhES2, KhES3, and H1, and the iPSCs 201B7 and 243G1. Embryoid bodies (EBs) formed without requiring supplementation with inducing factors. EBs also expressed some liver-specific metabolic genes including the ammonia-metabolizing enzymes glutamine synthetase and carbamoyl-phosphate synthase 1. Real-time PCR analysis revealed hepatocyte-like differentiation of EBs treated with ammonia in Lanford medium. Analysis of DNA microarray data suggested that hepatocyte-like cells were the most abundant population in ammonia-treated cells. Furthermore, expression levels of undifferentiated pluripotent stem cell markers were drastically reduced, suggesting a reduced teratoma-forming capacity. These results indicate that treatment of EBs with ammonia in Lanford medium may be an effective inducer of hepatic differentiation in absence of expensive inducing factors

Microarray data indicating the differentiation tendencies of six pluripotent stem cell lines.

<p>Heat maps of DNA microarray analysis (A, C) and the associated principal component analysis (B, D) of undifferentiated cells (A, B) and EB cells (C, D). Hierarchical Clustering; Similarity Measure: Euclidean; Linkage Rule: Complete. (E) Clipped representation from normalized microarray data showing pluripotent stem cell marker genes. (F) Quantitative PCR analysis of expression of endoderm markers Sox7 and Sox17, mesoderm marker Brachyury (T), and neuroectoderm marker NCAM1 in 253G1 cells. Each bar represents mean and SD (n = 3). Values are fold-change relative to the value of Sox7 in undifferentiated cells. *P < 0.05 compared with the value for undifferentiated cells. ML: undifferentiated maintenance culture on a MEF layer; MC: undifferentiated maintenance culture in MEF-conditioned medium on Matrigel; EB: embryoid bodies formed in static suspension culture.</p

DNA microarray data reveals hepatocyte-like differentiation of ammonia-treated cells.

<p>Results of DNA microarray analyses were combined and are presented as a heat map (A) and a principal component analysis (B). (C) Clipped representation from normalized microarray data showing hepatocyte related genes (upper) and control genes (lower). (D) Cell-type specificity of highly-expressed genes in ammonia-treated cells. Cell-type was annotated using GENATLAS (Paris Descartes University; <a href="http://genatlas.medecine.univ-paris5.fr/google/gene.php#" target="_blank">http://genatlas.medecine.univ-paris5.fr/google/gene.php#</a>). Left; “LIVER” indicates gene with high or predominant expression in organ(s) including the liver. “LIVER (specific)” indicates gene with high liver specific expression. “NON LIVER” indicates genes with high expression levels in organs other than the liver. “NO EXPRESSION” indicates genes without high expression. “UBIQUITOUS” indicates genes with ubiquitous expression (including liver expression). “UNKNOWN” indicates genes with no expression data. Right; breakdown of “NON LIVER”. (E) The top eight factors returned from TRANSFAC analysis of ammonia-treated cells. (F) Quantitative PCR analysis of <i>HNF4A</i>, <i>HNF-3beta</i> (<i>HNF3b</i>), and <i>HNF-1alpha</i> (<i>HNF1A</i>), gene expression levels in H1 ES cells. Each bar represents mean and SD (n = 3). Values are fold-change relative to the value of <i>HNF4A</i> in undifferentiated cells. *P < 0.05 compared with the value for undifferentiated cells. ML: undifferentiated maintenance culture on MEF layer; MC: undifferentiated maintenance culture in MEF-conditioned medium on Matrigel; EB: embryoid bodies formed in static suspension culture.</p

Genes, primers, and functions.

<p>Genes, primers, and functions.</p

Features of 6 pluripotent stem cells in cell handling.

<p>Features of 6 pluripotent stem cells in cell handling.</p

Expression of hepatocyte makers in EBs.

<p>Graphs depict quantitative PCR analysis of <i>AFP</i> (A), <i>albumin (ALB)</i>, <i>CYP3A7</i>, <i>OTC</i>, <i>SAA1</i>, <i>CPS1</i> (B) and <i>GLUL</i> (B, C) gene expression in H1 ES cells (A, B), KhES3 ES cells and 253G1 iPS cells (B). Each bar represents mean and SD (n = 3). Values are fold-change relative to the value for <i>ALB</i> in undifferentiated H1 cells (A, B) or undifferentiated KhES3 cells (C). *P < 0.05 compared with values for undifferentiated cells.</p