Molecular Characterization of Cultured Adult Human Liver Progenitor Cells

Abstract

Hepatic progenitor cells hold great promise as a self-renewing cell source for cell-based regenerative therapies as well as in vitro pharmacological testing. There is a fundamental need to identify and characterize these cells with respect to discriminative marker genes especially those encoding cell surface proteins, which can be utilized for the identification and isolation of these progenitor cells. In this study, comparative global gene expression profiling was performed with two epithelial cell types isolated from human livers that showed progenitor characteristics (type 1 and 2 cells), two human embryonic stem cell lines H1 and H9, and with primary human hepatocytes. The analysis revealed that the transcriptome of type 1 cells is more similar to that of human embryonic stem cells than to that of human hepatocytes. Among the list of genes expressed in type 1 cells are cadherins (CDH3), tight junction proteins (CLDN4), receptors (DDR1), integrins (ITGB4), cell adhesion molecules (EpCAM/TACSTD1), cell surface proteins (CD133/PROM1, ANXA3, and CD24), and a gene encoding the multidrug resistance protein MRP4/ABCC4. Finally, we were able to localize type 1 progenitor cells in Canals of Hering and in cells of ductular reactions within sections of normal and diseased human liver using ANXA3 and CLDN4 antibodies. Our study confirms the progenitor identity of type 1 cells and identifies novel markers that could be used for further studies on their characteristics and isolation using marker-based cell sorting strategies.

Discoidin Domain Receptor 1

“…Moreover, some individual DDR1-expressing oval cells, which are potentially HPCs, were observed near ductular reactions. This novel localization of DDR1 expression in cells that are probably HPCs elucidates the recent detection of DDR1 mRNA in human and rat HPCs 43,44 and deserves further investigation as to whether DDR1 expression has a role in differentiating HPCs into hepatocytes or bile duct cells.…”

Comparative Analysis of Human Embryonic Stem Cell and Induced Pluripotent Stem Cell-Derived Hepatocyte-Like Cells Reveals Current Drawbacks and Possible Strategies for Improved Differentiation

“…Based on these results, for each gene we obtained P values that indicate the magnitude of gene expression variation throughout the samples of the tested group. Additionally, a list of genes expressed in human liver progenitors (HLPs) generated by us [21] has been used.…”

“…Reverse transcription was carried out as previously described [21]. Real-time (RT)-polymerase chain reaction (PCR) was carried out on the Applied Biosystems 7900 instrument.…”

“…Chip hybridizations have been performed as previously described [21]. We hybridized the following samples in biological triplicates-Protocol 1 (P1) [5]: H1 cell line passage 53 (hESCs_P1, control), hepatocyte-like cells (hESCs-HLCs_P1); Protocol 2 (P2) [3]: H1 cell line passage 60 (hESCs_P2, control), hepatocyte-like cells (hESCs-HLCs_P2).…”

Human Hepatic Progenitor Cells Express Hematopoietic Cell Markers CD45 and CD109

“…In rodents 25-29, oval cells express markers of both hepatocyte and cholangiocyte lineages (such as albumin [ALB], cytokeratin 18 [CK18] and CK19) in addition to markers of both hematopoietic and mesenchymal stem cells (CD34, CD45 and CD90). In humans, HPCs with morphological features and immunohistological markers similar to those of oval cells have been characterized in normal liver and patients with chronic liver injury or submassive hepatic necrosis 30-36. Furthermore, these bipotent progenitor cells with characteristics similar to HPCs exist not only in human adult liver but also in human fetal liver 37, 38.…”