Efficient Differentiation of Human Pluripotent Stem Cells into Liver Cells

Summary

This protocol details a monolayer, serum-free method to efficiently generate hepatocyte-like cells from human pluripotent stem cells (hPSCs) in 18 days. This entails six steps as hPSCs sequentially differentiate into intermediate cell-types such as the primitive streak, definitive endoderm, posterior foregut and liver bud progenitors before forming hepatocyte-like cells.

Abstract

The liver detoxifies harmful substances, secretes vital proteins, and executes key metabolic activities, thus sustaining life. Consequently, liver failure—which can be caused by chronic alcohol intake, hepatitis, acute poisoning, or other insults—is a severe condition that can culminate in bleeding, jaundice, coma, and eventually death. However, approaches to treat liver failure, as well as studies of liver function and disease, have been stymied in part by the lack of a plentiful supply of human liver cells. To this end, this protocol details the efficient differentiation of human pluripotent stem cells (hPSCs) into hepatocyte-like cells, guided by a developmental roadmap that describes how liver fate is specified across six consecutive differentiation steps. By manipulating developmental signaling pathways to promote liver differentiation and to explicitly suppress the formation of unwanted cell fates, this method efficiently generates populations of human liver bud progenitors and hepatocyte-like cells by days 6 and 18 of PSC differentiation, respectively. This is achieved through the temporally-precise control of developmental signaling pathways, exerted by small molecules and growth factors in a serum-free culture medium. Differentiation in this system occurs in monolayers and yields hepatocyte-like cells that express characteristic hepatocyte enzymes and have the ability to engraft a mouse model of chronic liver failure. The ability to efficiently generate large numbers of human liver cells in vitro has ramifications for treatment of liver failure, for drug screening, and for mechanistic studies of liver disease.

Introduction

The purpose of this protocol is to efficiently differentiate human pluripotent stem cells (hPSCs) into enriched populations of liver bud progenitors and hepatocyte-like cells². Access to a ready supply of human liver progenitors and hepatocyte-like cells will accelerate efforts to investigate liver function and disease and could enable new cellular transplantation therapies for liver failure^3,4,5. This has proven challenging in the past since hPSCs (which include embryonic and induced pluripotent stem cells) can differentiate into all the cell-types of....

Protocol

1. Preparation of Differentiation Media

NOTE: Refer to the Table of Materials for manufacturer information regarding the materials and reagents used.

1. Preparation of base chemically defined media (CDM)
   NOTE: CDM2, CDM3, CDM4 and CDM5 are chemically defined media that are used as base medias for differentiating hPSCs to liver cells at various stages. The composition of these medias can be found in Table 1.
   1. To make CDM2 or CDM3, prepare a stock solution containing polyvinyl alcohol (PVA). Dissolve 0.5 g of PVA powder in 50 mL of Iscove’s Mo....

Results

After 24 h of APS differentiation, colonies will generally adopt a different morphology than undifferentiated colonies concomitant with a loss of the bright border that typically circumscribes hPSC colonies. Morphologically, primitive streak cells generally have ragged borders and are more spread and less compact than hPSCs-this is evocative of an epithelial-to-mesenchymal transition as pluripotent epiblast cells differentiate and ingress into the primitive streak in vivo. If the colony s.......

Discussion

This method enables the generation of enriched populations of liver bud progenitors, and subsequently hepatocyte-like cells, from hPSCs. The ability to generate enriched populations of human liver cells is important for the practical utilization of such cells. Previous methods to generate hepatocytes from hPSCs yielded impure cell populations containing both liver and non-liver cells that, upon transplantation into rodents, yielded bone and cartilage in addition to liver tissue¹⁵. Hence the explic.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Geltrex	Thermofisher Scientific	A1569601
1:1 DMEM/F12	Gibco	11320033
0.2 μm pore membrane filter	Millipore	GTTP02500
mTeSR1	Stem Cell Technologies	5850
Thiazovivin	Tocris Bioscience	3845
Accutase	Gibco or Millipore	Gibco A11105, Millipore  SCR005
IMDM, GlutaMAX™ Supplement	Thermofisher Scientific	31980030
Ham's F-12 Nutrient Mix, GlutaMAX™ Supplement	Thermofisher Scientific	31765035
KOSR, Knockout serum replacement	Thermofisher Scientific	10828028
Poly(vinyl alcohol)	Sigma-Aldrich	P8136
Transferrin	Sigma-Aldrich	10652202001
Chemically Defined Lipid Concentrate	Thermofisher Scientific	11905031
Human Activin	R&D	338-AC
CHIR99201	Tocris	4423
PI103	Tocris	2930/1
Human FGF2	R&D	233-FB
DM3189	Tocris	6053/10
A83-01	Tocris	2939/10
Human BMP4	R&D	314-BP
C59	Tocris	5148
TTNPB	Tocris	0761/10
Forskolin	Tocris	1099/10
Oncostatin M	R&D	295-OM
Dexamethasone	Tocris	1126
Ro4929097	Selleck Chem	S1575
AA2P	Cayman chemicals	16457
Human recombinant Insulin	Sigma-Aldrich	11061-68-0