Generation of 3D Liver Microtissues from Induced Pluripotent Stem Cells

The liver is a multifunctional organ essential for detoxification, protein synthesis, glucose regulation, bile secretion, and drug metabolism. However, persistent damage leads to chronic inflammation, excessive extracellular matrix deposition, and progressive fibrosis culminating in cirrhosis, for which liver transplantation remains the only curative option. Yet, the scarcity of donor organs and risks of immune rejection underscore the urgent need for physiologically relevant <i>in vitro</i> liver models to investigate pathogenesis and facilitate therapeutic discovery. Current two-dimensional cultures and animal models fail to recapitulate the multicellular interactions that govern liver homeostasis and disease progression. Hepatocytes (Heps) constitute the primary parenchymal population, while hepatic stellate cells (HSCs) and liver sinusoidal endothelial cells (LSECs) coordinate fibrogenic, angiogenic, and regenerative responses. Dysregulation of this crosstalk drives fibrosis and architectural collapse, highlighting the necessity for multicellular systems that mimic native liver complexity. In this study, we established a three-dimensional (3D) microtissue platform that recapitulates both the structural and functional characteristics of the human liver. Human-induced pluripotent stem cells (hiPSCs) were differentiated into Heps, HSCs, and LSECs, which were subsequently cocultured within a self-organizing 3D microenvironment. We successfully reconstructed a miniaturized liver model that maintains hepatic functionality and exhibits steatogenic responses to alcohol exposure. This hiPSC-derived microtissue enables the modeling of chronic liver diseases, intercellular signaling, and fibrogenic pathways, thereby providing a translationally relevant system for mechanistic studies, drug toxicity testing, and personalized therapeutic development.