Exploring the role of HNF4α in hepatic differentiation from pluripotent stem cells

Abstract

Pluripotent stem cells can give rise to all cell types found in the human body. Directed hepatic differentiation of pluripotent stem cells offers a great model for studying hepatocyte biology.

A transcription factor named hepatocyte nuclear factor 4 alpha (HNF4a) governs the differentiation and function of human hepatocytes. This thesis explores the role of HNF4a in hepatic differentiation from human pluripotent stem cells. The genome editing tool CRISPR-Cas9 was employed to generate human pluripotent stem cell lines with different forms of HNF4a. Cells with the mutated form of HNF4a without the DNA-binding domain failed in hepatic specification. Meanwhile, cells with a mutated SUMOylation consensus motif in the C-terminus of HNF4a reached the hepatic progenitor stage, but failed in hepatocyte specification. Genome-wide microarray, metabolomics and proteomics analysis identified a large number of dysregulated targets in cells with modified HNF4a. We propose that HNF4a plays an important role in tricarboxylic acid cycle flux and mitochondria function, and those are essential to hepatic specification and differentiation from pluripotent stem cells.