FOXM1 inhibition primes terminal differentiation of human iPSC-derived hepatocytes

Human iPSC-derived hepatocytes are widely used in disease modeling. However, late embryonic development in the human liver remains elusive, which hinders differentiation. During late liver embryonic development, Topoisomerase II (TOP2) is downregulated; however, its role in differentiation is unclear. We replicated the TOP2 silencing at birth and identified a transcription factor crucial for hepatocyte differentiation in vitro. Subtoxic inhibition of TOP2 reduces nuclear chromatin condensation without causing DNA damage. RNA-seq analysis revealed that TOP2 inhibition induced cell cycle arrest, accompanied by FOXM1 downregulation. ATAC-seq confirmed that TOP2A inhibition decreased chromatin accessibility and modulated the Wnt/β-catenin pathway. Proteomic analysis demonstrated that FOXM1 inhibition mimicked TOP2A-mediated cell cycle arrest and reduced the levels of fetal hepatocyte proteins. Prolonged FOXM1 inhibition results in increased hepatocyte polyploidization, enhanced CYP450 activity, and improved lipid metabolism. Our findings suggest that FOXM1 inhibition promotes terminal differentiation of human iPSC-derived hepatocytes, potentially paving the way for understanding late embryonic development in the human liver.