Histone deacetylase inhibitor valproic acid promotes the differentiation of human induced pluripotent stem cells into hepatocyte-like cells.

Yuki Kondo,Masayoshi Saito,Naoki Miyata,Kayo Mimori,Takayoshi Suzuki,Takahiro Iwao,Kiyoshi Nagata,Kouichi Kurose,Shigeru Ohmori,Takuro Niwa,Ruri Ogihara,Sachimi Yoshihashi,Katsunori Nakamura,Tamihide Matsunaga,Rajasingh Johnson

doi:10.1371/journal.pone.0104010

Abstract

In this study, we aimed to elucidate the effects and mechanism of action of valproic acid on hepatic differentiation from human induced pluripotent stem cell-derived hepatic progenitor cells. Human induced pluripotent stem cells were differentiated into endodermal cells in the presence of activin A and then into hepatic progenitor cells using dimethyl sulfoxide. Hepatic progenitor cells were matured in the presence of hepatocyte growth factor, oncostatin M, and dexamethasone with valproic acid that was added during the maturation process. After 25 days of differentiation, cells expressed hepatic marker genes and drug-metabolizing enzymes and exhibited drug-metabolizing enzyme activities. These expression levels and activities were increased by treatment with valproic acid, the timing and duration of which were important parameters to promote differentiation from human induced pluripotent stem cell-derived hepatic progenitor cells into hepatocytes. Valproic acid inhibited histone deacetylase activity during differentiation of human induced pluripotent stem cells, and other histone deacetylase inhibitors also enhanced differentiation into hepatocytes. In conclusion, histone deacetylase inhibitors such as valproic acid can be used to promote hepatic differentiation from human induced pluripotent stem cell-derived hepatic progenitor cells.

Highlights

Induced pluripotent stem cells, originally generated from human fibroblasts, are pluripotent and have infinite proliferative potential in vitro [1]
Hepatic differentiation from Human iPS (hiPS) cells was evaluated by measuring the expression of ALB, a-fetoprotein (AFP), and tyrosine aminotransferase (TAT), which are hepatocyte-specific marker proteins, and of the pregnane X receptor (PXR), which is a nuclear receptor that regulates cytochrome P450 (CYP) 3A4 expression
The mRNA expression of ALB in differentiated cells after the 168h Valproic acid (VPA) treatment was 42-fold higher than that detected in human primary hepatocytes (HPHs) 48 h, and the mRNAs of TAT and PXR were expressed at levels that were similar to those of HPHs 48 h

Summary

Introduction

Induced pluripotent stem (iPS) cells, originally generated from human fibroblasts, are pluripotent and have infinite proliferative potential in vitro [1]. Human iPS (hiPS) cells are expected to have various applications, including for studying hepatic drug metabolism and toxicity [2]. Hepatic differentiation methods that use a combination of cytokines and overexpression of transcriptional factors by viral vectors or coculture with other cells have been reported [7,8,9,10]. These methods enhance hepatic functions in differentiated cells, they require considerable technical skills and specialized materials such as modified adenoviruses. Large-scale production of hiPS cellderived hepatocytes is needed for drug development studies and cell transplantation. It is difficult to prepare the reagents required for differentiation of these cells in sufficient quantities using the methods reported previously, and product validation is required

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