Human-induced pluripotent Stem Cell-Derived Hepatic Stellate Cells in Liver Organoids: Maturation Promotion and Essential Role in Vascularization

Human-induced pluripotent stem cell (hiPSC)-derived liver organoids (LOs) are valuable for studying human liver organogenesis but face challenges in faithfully recapitulating certain processes, like vasculogenesis, due to the lack of specific cell components. Hepatic stellate cells (HSCs), which are liver-specific pericytes and might be crucial for liver vasculogenesis, remain underutilized in developmental studies because of their disease-related "activated" status and inefficient generation process. Here, we present an efficient method for generating hiPSC-derived HSCs (hiPSC-HSCs) resembling non-activated HSCs in the healthy human liver. These hiPSC-HSCs exhibit exceptional expandability (>105-fold) while maintaining essential cellular features. Additionally, in entirely hiPSC-derived LOs consisting of HSCs, hepatic endoderm, and endothelial cells, hiPSC-HSCs play a vital role in LO maturation and vascularization, both in vitro and in vivo. This work represents a significant advancement in understanding HSC roles in human liver development, and LOs containing non-activated hiPSC-HSCs hold potential in modeling congenital human liver diseases.