Figure 1.

Methods for generating liver organoids for disease modeling. Liver organoids can be broadly classified into adult stem cell (ASC)-derived liver organoids and pluripotent stem cell (PSC)-derived liver organoids. ASC-derived liver organoids are generated by stem-like cells derived from tissue biopsies. Bipotent intrahepatic cholangiocyte organoids (ICOs) can be derived from EPCAM+ biliary cell populations isolated from diseased or healthy liver biopsies. Such cells tend to be refractory toward hepatocyte differentiation. The hepatocyte population from a liver biopsy can be dedifferentiated into proliferating hepatocyte organoids that can be stably propagated and subsequently induced to form functional hepatocytes. Patient-derived iPSCs can generate different organoid types via a stepwise differentiation strategy along the endoderm lineage (DE, definitive endoderm; PFG, posterior foregut; HE, hepatic endoderm). This includes multi-tissue hepato-biliary-pancreatic (HBP) organoids, multi-cellular organoids containing both liver parenchymal (hepatocytes) and non-parenchymal (hepatic stellate cells [HSCs] and Kupffer cells [KCs]) cell types, hepatobiliary organoids containing parenchymal hepatocytes and cholangiocytes, and single cell type hepatocyte or cholangiocyte organoids. HE can also be co-cultured with endothelial cells (ECs) and mesenchymal cells (MCs) to form a liver bud that generates vascularized tissue when engrafted. Fibroblast over-expressing (OE) SV40 large T antigen (SV40LT) can be directly transdifferentiated into hepatocyte organoids with a combination of hepatocyte-inducing factors. The organoids can be subsequently manipulated in culture to model various liver diseases.